A method for determining the position of the groove of a transmission bearing seat

Abstract

The present invention relates to a method for determining the position of a groove in a transmission bearing seat, including building a finite element model of the transmission housing assembly based on a bearing seat without a groove; defining the material properties of the finite element model; applying the boundary conditions of the finite element model; defining the initial temperature of the finite element model; applying Load 1, Load 2, Load 3 and Load 4; defining the calculation conditions; performing finite element analysis; determining the position of the groove in the bearing seat; building a finite element model of the transmission housing assembly based on a bearing seat with a groove and performing finite element analysis. The present invention effectively improves the reliability of the bearing seat, with accurate position determination and high efficiency; simplifies the process of determining the groove position, enabling different engineers to objectively determine the groove position; the contact pressure distribution of the obtained bearing seat is more consistent with the actual situation, and the determined groove position of the bearing seat is also more effective; it realizes saving the calculation time of the finite element model and shortening the product development cycle without affecting the accurate determination of the groove position in the bearing seat.

Description

Technical Field

[0001] The present invention belongs to the technical field of transmissions, and particularly relates to a method for determining the position of a groove in a transmission bearing seat. Background Art

[0002] In a passenger vehicle transmission assembly, the thermal expansion coefficient of the cast aluminum bearing seat material is about twice that of the bearing steel. When the temperature rises, the expansion amount of the bearing seat is greater than that of the outer ring of the bearing. When a gap appears between the bearing seat and the outer ring of the bearing and the frictional force alone is not sufficient to fix the outer ring of the bearing, under the action of the rolling torque of the bearing rollers, the outer ring of the bearing will rotate circumferentially within the bearing seat, resulting in mutual wear between the outer ring of the bearing and the bearing seat and affecting the positioning accuracy of the gear shaft.

[0003] In order to effectively prevent relative rotation between the outer ring of the bearing and the bearing seat, a groove needs to be opened on the bearing seat. The groove is used to place a spring pin for positioning the rotation of the outer ring of the bearing. The shape of the groove changes drastically and has a large stress concentration coefficient. If the opening position is incorrect, the groove will be at a high stress level, leading to cracking and failure of the bearing seat. Therefore, on the premise of fully considering the stress state of the bearing seat, the groove should be opened at a position with lower stress to ensure the reliability of the bearing seat.

[0004] Currently, in textbooks, for example, "Mechanical Design" edited by Li Liangjun only gives the axial positioning method of the outer ring of the bearing, but does not give the method for positioning the circumferential movement of the outer ring of the bearing. The prior art discloses a transmission mechanism, a bearing transmission structure and a bearing seat. However, it does not rely on the groove of the bearing seat and the spring pin to position the outer ring of the bearing, but uses an interference fit to fix the outer ring of the bearing in the bearing seat. When the temperature of the transmission rises, it uses the deformation of the isolation groove opened on the side wall of the bearing seat to compensate for the gap between the outer ring of the bearing and the bearing seat to prevent the circumferential rotation of the outer ring of the bearing. It has the following disadvantages: 1. The amount of gap compensated by the isolation groove is limited, and the outer ring can still rotate circumferentially when the temperature rises; 2. If the interference amount between the outer ring and the bearing seat is increased, it is easy to cause a large bearing frictional torque, reducing the transmission efficiency, and there is a high risk of cracking of the isolation groove at low temperature; 3. Arranging the isolation groove requires a large space, and the local space of the bearing seat in the transmission is small, and the isolation groove cannot be arranged. Therefore, it is considered that this structure cannot be applied to passenger vehicle transmission products. The prior art also discloses a method for optimizing the design of a wind turbine bearing seat structure based on finite element, which uses the finite element method to optimize the bearing seat. It does not carry out optimization and corresponding technical research on positioning the circumferential rotation of the outer ring of the bearing, nor does it involve opening a groove on the bearing seat. The prior art also discloses a new type of bearing seat with an anti-rotation structure, and a hole for placing an oil injection pile is opened on the bearing seat. This hole does not have the function of restricting the circumferential rotation of the components inside the bearing seat, and it also does not explain what factors should be considered when opening the hole and accordingly where to specifically open the hole.

[0005] In summary, none of the existing technologies provides a technical solution for determining the position of the bearing housing groove in order to prevent the rotation of the outer ring of the bearing by using the cooperation between the bearing housing groove and the spring pin. Summary of the Invention

[0006] The object of the present invention is to provide a method for determining the position of the bearing housing groove of a transmission, so as to solve the problem of determining the position of the bearing housing groove, ensuring the reliability of the bearing housing while preventing relative rotation between the outer ring of the bearing and the bearing housing.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] A method for determining the position of the bearing housing groove of a transmission includes the following steps:

[0009] S1. Build a finite element model for the assembly of the transmission housing based on the bearing housing without a groove: Mesh the two split housings, input shaft, intermediate shaft, differential housing, bearings, snap rings, gaskets, gears, bolts, side covers, and hydraulic control modules respectively, and assemble them together by defining the contact relationship between the contacting components.

[0010] S2. Define the material properties of the finite element model: Define the elastic modulus E, Poisson's ratio μ, and coefficient of thermal expansion α of the materials of the finite element models of each component.

[0011] S3. Apply the boundary conditions of the finite element model: The boundary conditions include two types. One is to fix the bolt holes of the split housing connected to the engine flywheel housing to simulate the support of the flywheel housing to the transmission. The other is to fix the rotational degrees of freedom of each gear shaft and differential housing around their respective axis lines.

[0012] S4. Define the initial temperature of the finite element model: Apply the initial temperature to the split housing, input shaft, intermediate shaft, differential housing, bearings, snap rings, gaskets, gears, bolts, side covers, and hydraulic control modules, and the initial temperature is defined as room temperature.

[0013] S5. Apply Load 1: Load 1 is the bolt pre-tightening force, which is obtained from the relationship between the bolt pre-tightening force and the bolt tightening torque, and then applied to the bolts.

[0014] S6. Apply Load 2: Load 2 is the temperature load, that is, apply a high temperature load to the split housing, input shaft, intermediate shaft, differential housing, bearings, snap rings, gaskets, gears, bolts, side covers, and hydraulic control modules.

[0015] S7. Apply Load 3: Load 3 is the gear meshing force when the transmission is in any forward gear. The gear meshing force is obtained according to the torque M transmitted by the gear shaft, the gear meshing parameters, and the gear load calculation formula, and then applied to the gears through which the forward gear torque passes;

[0016] S8. Apply Load 4: Load 4 is the gear meshing force when the transmission is in reverse gear. The gear meshing force is obtained according to the torque M transmitted by the gear shaft, the gear meshing parameters, and the gear load calculation formula, and then applied to the gears through which the reverse gear torque passes;

[0017] S9. Define the calculation conditions

[0018] Calculation Condition 1: Includes the boundary conditions in Step S3, the initial temperature in Step S4, Load 1 in Step S5, Load 2 in Step S6, and Load 3 in Step S7;

[0019] Calculation Condition 2: Includes the boundary conditions in Step S3, the initial temperature in Step S4, Load 1 in Step S5, Load 2 in Step S6, and Load 4 in Step S8;

[0020] S10. Conduct finite element analysis: According to the sequence of Calculation Condition 1 and Calculation Condition 2 defined in Step S9, calculate the contact pressure on the bearing seat surface in contact with the outer bearing ring in turn;

[0021] S11. Determine the position of the bearing seat groove: Linearly superimpose the bearing seat surface contact pressure obtained from Calculation Condition 1 in Step S10 and the bearing seat surface contact pressure obtained from Calculation Condition 2 to obtain the overall distribution of the bearing seat surface contact pressure, and select the area with a smaller contact pressure to open the bearing seat groove;

[0022] S12. Build a finite element model of the transmission housing assembly based on the bearing seat with a groove and conduct finite element analysis: Repeat Steps S1 - S10 to calculate the stress of the bearing seat. If the stress of the bearing seat groove is less than the allowable stress, it indicates that the position of the opened groove has a good effect; otherwise, it is necessary to repeat Step S11 and re - select the position with a smaller bearing seat contact pressure to open the groove until the stress of the bearing seat groove is less than the allowable stress.

[0023] Furthermore, in Step S1, the mesh nodes on the outer surface of the outer bearing ring correspond one - to - one with the mesh nodes on the inner surface of the split - type housing bearing seat in contact with it. The gears supported by the input shaft are connected to the input shaft, the gears supported by the intermediate shaft are connected to the intermediate shaft, and the gears supported by the differential housing are connected to the differential housing by the co - node method. There is a zero - clearance fit between the bearing and the bearing seat.

[0024] Furthermore, in step S3, the rotational degrees of freedom of the gear shaft and differential case need to be fixed with the help of RBE3 units. The RBE3 unit slave point is defined on the axis centerline, and the master point is selected as a node on a cross section on the gear shaft and differential case. The cross section is located between the bearing and the gear. The rotational degrees of freedom of the RBE3 unit slave point about the axis centerline are constrained. An RBE3 unit needs to be established between each gear and the bearing, and the rotational degrees of freedom of all RBE3 unit slave points about the axis centerline are fixed.

[0025] Furthermore, in step S5, the bolt preload force is calculated using formula (1), and the action direction is along the axial direction of the bolt;

[0026]

[0027] Where F is the bolt preload, T is the bolt tightening torque, k is the bolt tightening torque coefficient, and D is the bolt diameter.

[0028] Furthermore, in step S6, the temperature applied to the split housing, input shaft, intermediate shaft, differential housing, bearings, snap rings, gaskets, gears, bolts, side covers, and hydraulic control module is the same, and the temperature value is greater than the normal operating temperature value of the transmission.

[0029] Furthermore, in step S7, the forward gear should include the least number of gears to shorten the calculation cycle, and the included gears should allow the input shaft assembly, the intermediate shaft assembly, and the differential assembly to transmit torque at least once. The forward gears should be determined in sequence from the first gear to the highest gear.

[0030] Furthermore, the method for determining the position of a transmission bearing seat groove according to claim 1 is characterized in that, in steps S7 to S8, the meshing force of each gear can be decomposed into circumferential force, radial force and axial force, which are calculated using formula (2) and applied with the help of a local cylindrical coordinate system defined on the axis of each gear shaft, wherein the Z axis of the coordinate system is along the axis of the gear shaft, R is along the radial direction of the gear shaft, and t is determined by Z and R according to the right-hand rule;

[0031]

[0032] Where, F t 、F r 、F a They are the circumferential force, radial force and axial force of the gear respectively, M is the torque transmitted by the gear, d is the pitch diameter of the gear, a n is the gear normal pressure angle, β is the helix angle at the gear pitch circle;

[0033] Gear circumferential force F t , radial force F r and axial force F aIt is applied to the gear meshing nodes by means of RBE3 elements. The slave points of the RBE3 elements select the gear meshing nodes, and the master points of the RBE3 elements select the tooth surface unit nodes of at least 2 teeth near the gear meshing nodes.

[0034] Further, in the step S9, the calculation condition 1 calculates according to the number of gears determined in the step S7, and the calculation condition 2 calculates according to the number of gears determined in the step S8, and can be further divided into sub-calculation conditions, that is, one gear corresponds to one sub-calculation condition.

[0035] Further, in the step S11, the area with zero contact pressure in the overall distribution of the bearing seat surface contact pressure is determined as the bearing seat groove position.

[0036] Further, in the step S12, the allowable stress is the yield strength of the material.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. The present invention details the steps for determining the bearing seat groove position from aspects such as finite element model construction, calculation condition selection, and result analysis. By calculating and linearly superposing the bearing seat contact pressures under typical conditions, the overall distribution of the bearing seat contact pressure is obtained, and the bearing seat groove position is directly determined in the area with lower bearing seat contact pressure, effectively improving the reliability of the bearing seat. Its position is accurately determined and the efficiency is high; by directly analyzing the overall distribution of the bearing seat pressure, it avoids the cumbersome process of manually repeatedly analyzing and judging the bearing seat contact pressure distribution under numerous typical conditions, simplifies the process of determining the groove position, and enables different engineers to objectively determine the groove position;

[0039] 2. When calculating the bearing seat contact pressure distribution for typical gears, the influence of the temperature of the transmission components is considered, which is more consistent with the actual working state of the transmission. The obtained bearing seat contact pressure distribution is more consistent with the actual situation, and the determined bearing seat groove position is also more effective.

[0040] 3. Typical gears are reasonably selected from all gears of the transmission for calculating the bearing seat contact pressure, achieving the saving of the finite element model calculation time and shortening of the product development cycle without affecting the accurate determination of the bearing seat groove position. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0042] Figure 1 It is a schematic diagram of the transmission assembly structure (angle 1);

[0043] Figure 2 It is a schematic diagram of the transmission assembly structure (angle 2);

[0044] Figure 3 It is a schematic diagram of the internal gear transmission mechanism of the transmission (angle 1);

[0045] Figure 4 It is a schematic diagram of the internal gear transmission mechanism of the transmission (angle 2);

[0046] Figure 5 It is a schematic diagram of the internal gear transmission mechanism of the transmission (angle 3);

[0047] Figure 6 It is a schematic diagram of the split housing;

[0048] Figure 7 It is a schematic diagram of the grid on the outer surface of the bearing and the inner surface of the bearing seat;

[0049] Figure 8 It is a schematic diagram of the differential assembly;

[0050] Figure 9 It is a schematic diagram of the RBE3 element established on the differential housing;

[0051] Figure 10 It is at Figure 9 A schematic diagram of the RBE3 element established by locally magnifying area A in;

[0052] Figure 11 It is the contact pressure distribution on the inner surface of the bearing seat when the transmission is in the first gear;

[0053] Figure 12 It is the contact pressure distribution on the inner surface of the bearing seat when the transmission is in the third gear;

[0054] Figure 13 It is the contact pressure distribution on the inner surface of the bearing seat when the transmission is in reverse gear;

[0055] Figure 14 It is Figures 11 to 13 The linear superposition distribution diagram of the contact pressure on the inner surface of the bearing seat;

[0056] Figure 15 It is a schematic diagram of the position of the groove in the bearing seat;

[0057] Figure 16 It is Figure 15 The local enlarged view of area C in;

[0058] Figure 17 It is the stress distribution of the bearing seat when the transmission is in the first gear;

[0059] Figure 18 It is the stress distribution of the bearing seat when the transmission is in the third gear;

[0060] Figure 19 It is the stress distribution of the bearing seat when the transmission is in reverse gear.

[0061] In the figure, 1. Bolt 2. Side cover 3. Hydraulic control module 11. Split housing I 12. Split housing II 21. Input shaft 22. Intermediate shaft I 23. Intermediate shaft II 24. Differential housing 31. Bearing I 32. Bearing II 33. Bearing III 34. Bearing IV 35. Bearing V 36. Bearing VI 37. Bearing VII 38. Bearing VIII 41. Snap ring I 42. Snap ring II 43. Snap ring III 44. Snap ring IV 51. Gasket 61. Gear I 62. Gear II 63. Gear III 64. Gear IV 71. Gear V 72. Gear VI 73. Gear VII 81. Gear VIII 82. Gear IX 83. Gear X 111. Bearing seat 112. Bearing seat groove 113. Spring pin 240. Section I 241. Section II 242. RBE3 element I 243. From point 244. Axis line 245. Local cylindrical coordinate system 246. RBE3 element II 247. From point 248. Tooth surface I 249. Tooth surface II. Specific implementation manner

[0062] The present invention will be further described below in conjunction with embodiments:

[0063] In order to effectively prevent relative rotation between the outer ring of the bearing and the bearing seat, a groove needs to be opened on the bearing seat, and the groove is used to place a spring pin for positioning the rotation of the outer ring of the bearing. The shape of the groove changes violently and has a large stress concentration coefficient. If the opening position is incorrect, the groove will be at a high stress level, leading to cracking failure of the bearing seat. Therefore, on the premise of fully considering various stress states of the bearing seat, the groove should be opened at a position with a lower stress level to ensure the reliability of the bearing seat.

[0064] A method for determining the position of the groove of a transmission bearing seat, characterized by comprising the following steps,

[0065] S1. Build a finite element model of the transmission housing assembly based on the bearing seat without a groove:

[0066] As Figures 1 to 5As shown, mesh generation is performed on the split housing I 11, split housing II 12, input shaft 21, intermediate shaft 22, intermediate shaft 23, differential housing 24, bearings I 31 to bearings VIII 38, snap rings I 41 to snap rings IV 44, gaskets 51, gears I 61 to gears IV 64, gears V 71 to gears VII 73, gears VIII 81 to gears X 83, bolts 1, side covers 2, and hydraulic control modules 3. Then, they are assembled together by defining the contact relationship between the contacting components. The contacting components have a zero-clearance fit, and interference is not considered.

[0067] In step S1, the mesh nodes on the outer surface of the bearing outer ring correspond one-to-one with the mesh nodes on the inner surface of the bearing seat of the split housing they contact, so as to improve the calculation accuracy of the contact pressure of the bearing hole and the stress of the bearing seat. Taking bearing 31 and bearing seat 111 as an example, as Figures 6 to 7 shown, the mesh nodes on the outer surface of the outer ring of bearing 31 correspond one-to-one with the mesh nodes on the inner surface of the corresponding part of bearing seat 111. For the convenience of display, the two parts of mesh nodes are shown separately.

[0068] In step S1, the gears I 61, gears V 71, and gears VIII 81 supported by the input shaft 21 are connected to the input shaft 21 in a co-node manner. The gears VI 72, gears VII 73, and gears IX 82 supported by the intermediate shaft I 22 are connected to the intermediate shaft I 22 in a co-node manner. The gears II 62, gears III 63, and gears X 83 supported by the intermediate shaft II 23 are connected to the intermediate shaft II 23 in a co-node manner. The gear IV 64 supported by the differential housing 24 is connected to the differential housing 24 in a co-node manner. Using this connection method can effectively reduce the scale of the finite element model and improve the calculation efficiency without affecting the calculation accuracy.

[0069] In step S1, interference is not considered between the bearing and the bearing seat, and it has a zero-clearance fit.

[0070] S2. Define the material properties of the finite element model:

[0071] The materials of the split housing I 11, split housing II 12, side cover 2, and hydraulic control module 3 are aluminum alloy AlSi9Cu3, with elastic modulus E = 71000 MPa, Poisson's ratio μ = 0.33, and α = 0.0000212 / °C; the material of the differential housing 24 is ductile iron QT600, E = 17500 MPa, Poisson's ratio μ = 0.3, and α = 0.0000118 / °C; the others are ferroalloys, E = 210000 MPa, Poisson's ratio μ = 0.3, and α = 0.0000127 / °C.

[0072] S3. Apply the boundary conditions of the finite element model:

[0073] The boundary conditions include two categories. One is to fix the bolt holes 4 on the split housing Ⅰ11 connected to the engine flywheel housing ( Figure 2 ), to simulate the support of the flywheel housing for the transmission; the other is to fix the rotational degrees of freedom of each gear shaft and the differential housing around their respective axis lines. Taking the differential housing 24 as an example ( Figures 8 to 9 ), at the cross-section 241 between the bearing Ⅷ38 and the gear Ⅳ64, an RBE3 element 242 is established. The RBE3 element 242 is defined from point Ⅰ243 on the axis line 244 of the differential housing 24, and the master point selects the node on the cross-section Ⅱ241. The six degrees of freedom of the slave points are constrained in the cylindrical coordinate system 245; at the cross-section Ⅰ240 between the bearing 34 and the gear Ⅳ64, a new RBE3 element is established in the same way as the RBE3 element Ⅰ242, and the six degrees of freedom of its slave points are constrained; for the input shaft 21, the intermediate shaft 22, and the intermediate shaft 23, new RBE3 elements need to be established in the same way as the RBE3 element Ⅰ242, and the rotational degrees of freedom of their slave points around their own axis lines are constrained.

[0074] S4. Define the initial temperature of the finite element model:

[0075] Apply the initial temperature to the split housing, input shaft, intermediate shaft, differential housing, bearings, snap rings, gaskets, gears, bolts, side covers, and hydraulic control modules. The temperature value is equal to the room temperature of 25°C.

[0076] S5. Apply load 1:

[0077] Load 1 is the bolt pre-tightening force, which is obtained from the relationship between the bolt pre-tightening force and the bolt tightening torque, and then applied to the bolts; the bolt pre-tightening force is calculated using formula (1), and the acting direction is along the axial direction of the bolts;

[0078]

[0079] In the formula, F is the bolt pre-tightening force, T is the bolt tightening torque, k is the bolt tightening torque coefficient, D is the bolt diameter, and k is recommended to be taken as 0.2.

[0080] S6. Apply load 2:

[0081] Load 2 is the temperature load, that is, the same temperature is applied to the split housing, input shaft, intermediate shaft, differential housing, bearings, snap rings, gaskets, gears, bolts, side covers, and hydraulic control modules. The temperature value is greater than the normal operating temperature value of the transmission. In this embodiment, the temperature is equal to 120°C.

[0082] S7. Apply load 3:

[0083] The load 3 is the gear meshing force when the transmission is in any forward gear. The gear meshing force is obtained according to the torque M transmitted by the gear shaft, the gear meshing parameters and the gear load calculation formula (2), and then applied to the gears through which the forward gear torque passes;

[0084] The forward gears should include the fewest number of gears to shorten the calculation cycle. The included gears should at least enable the input shaft assembly, the intermediate shaft assembly and the differential assembly to all transmit torque once.

[0085] In the embodiment, the forward gear calculation gears include the first gear and the third gear. When in the first gear, the gear load 31 is applied, and when in the third gear, the gear load 33 is applied. These two gears are representative. The first gear is the lowest gear on the intermediate shaft II 23, and the third gear is the lowest gear on the intermediate shaft I 22. The two speed ratios are relatively large, and the gear meshing force during the torque transmission process is relatively large. Calculating the transmission housing stress according to these two gears can effectively ensure the strength of the transmission housing bearing seat and improve the structural reliability; The torque of the first gear passes through the input shaft 21, the intermediate shaft II 23 and the differential housing 24, and the torque of the third gear passes through the input shaft 21, the intermediate shaft I 22, and the differential housing 24. As Figures 3 to 5 shown, the gears through which the torque of the first gear passes include the gear I 61 on the input shaft 21, the gear II 62 and the gear III 63 on the intermediate shaft II 23, and the gear IV 64 on the differential housing 24. The gears through which the torque of the third gear passes include the gear V 71 on the input shaft 21, the gear VI 72 and the gear VII 73 on the intermediate shaft I 22, and the gear IV 64 on the differential housing 24.

[0086] Each gear meshing force can be decomposed into a circumferential force, a radial force and an axial force, which are calculated using formula (2) and applied by means of the local cylindrical coordinate system 245 defined on the axis of each gear shaft. As Figure 9 shown, the Z-axis of the coordinate system is along the axis direction, R is along the radial direction, and t is determined by Z and R according to the right-hand rule;

[0087]

[0088] In the formula, F t 、F r 、F a are the circumferential force, the radial force and the axial force of the gear respectively, M is the torque transmitted by the gear, d is the pitch circle diameter of the gear, a n is the normal pressure angle of the gear, and β is the helix angle at the pitch circle of the gear;

[0089] As Figures 9 to 10As shown, taking gear Ⅳ64 as an example, the process of applying the gear meshing force is described. The process of applying the gear meshing force for other gears is the same as that of gear Ⅳ64. The gear meshing force of gear Ⅳ64 is applied by means of RBE3 element Ⅱ246. The slave point Ⅱ247 of RBE3 element Ⅱ246 selects the gear meshing node, and the master point of RBE3 element Ⅱ246 selects the element nodes on tooth surface Ⅰ248 and tooth surface Ⅱ249 near the gear meshing node.

[0090] S8. Apply Load 4:

[0091] Load 4 is the gear meshing force when the transmission is in reverse gear. The gear meshing force is obtained according to the torque M transmitted by the gear shaft, the gear meshing parameters and the gear load calculation formula (2), and then applied to the gears that the reverse gear torque passes through, such as Figures 3 to 5 As shown, the gears that the reverse gear torque passes through include gear Ⅷ81 on the input shaft 21, gear Ⅸ82 on the intermediate shaft Ⅰ22, gear Ⅹ83 and gear Ⅲ63 on the intermediate shaft Ⅱ23, and gear Ⅳ64 on the differential housing 24. The gears included in the reverse gear are gears with a relatively large speed ratio.

[0092] S9. Define the calculation conditions:

[0093] Calculation condition 1 is based on the number of gears determined in step S7, and calculation condition 2 is based on the number of gears determined in step S8. It can be further divided into sub-calculation conditions, that is, one gear corresponds to one sub-calculation condition.

[0094] Calculation condition 11: includes the boundary conditions in step S3, the initial temperature in step S4, load 1 in step S5, load 2 in step S6, and load 31 in the first gear in step S7;

[0095] Calculation condition 12: includes the boundary conditions in step S3, the initial temperature in step S4, load 1 in step S5, load 2 in step S6, and load 33 in the third gear in step S7;

[0096] Calculation condition 2: includes the boundary conditions in step S3, the initial temperature in step S4, load 1 in step S5, load 2 in step S6, and load 4 in step S8.

[0097] S10. Conduct finite element analysis:

[0098] According to the sequence of calculation condition 11, calculation condition 12, and calculation condition 2 defined in step S9, calculate the contact pressure on the bearing seat surface in contact with the outer ring of the bearing in turn. Taking the bearing seat 111 as an example, the internal surface contact pressure distributions corresponding to condition 11, condition 12, and condition 2 are respectively as Figures 11 to 13 shown.

[0099] S11. Determine the position of the bearing seat groove:

[0100] Determine the position of the bearing housing groove as the area where the contact pressure is zero in the overall distribution of the bearing housing surface contact pressure. Linearly superimpose the bearing housing surface contact pressures obtained in calculation condition 11, calculation condition 12, and calculation condition 2 in step S10 to obtain the overall distribution of the bearing housing surface contact pressure as shown in Figure 14 shown. Select area B with a relatively small contact pressure to open the bearing housing groove 112, as shown in Figures 15 to 16 shown. A spring pin 113 for preventing the outer ring of bearing Ⅰ31 from rotating is placed in the groove 112. When the temperature of the transmission is relatively high, the spring pin 113 can still effectively prevent the outer ring of bearing 31 from rotating.

[0101] S12. Build a finite element model of the transmission housing assembly based on the bearing housing with a groove and perform finite element analysis:

[0102] Repeat steps S1 to S10. The stress distributions of the bearing housing corresponding to the three working conditions in step S9 are as shown in Figures 17 to 19 shown. It can be seen from the figure that the stresses at the groove positions are all less than the material yield strength limit of 140 MPa, and the stresses are relatively small, meeting the strength requirements, and the effect of the groove opening position is good. If the stress of the bearing housing groove is less than the allowable stress, it indicates that the effect of the groove opening position is good; otherwise, step S11 needs to be repeated to re-select the position with a relatively small contact pressure of the bearing housing to open the groove until the stress of the bearing housing groove is less than the allowable stress. The allowable stress is the yield strength of the material.

[0103] Note that the above is only the preferred embodiment of the present invention and the applied technical principle. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described here, and various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A method for determining the position of a groove in a transmission bearing seat, characterized in that, It includes the following steps: S1. Build a finite element model for the transmission housing assembly based on the bearing housing without grooves: Mesh the two split housings, the input shaft (21), the two intermediate shafts, the differential housing (24), multiple bearings, multiple snap rings, the gasket (51), multiple gears, the bolts (1), the side cover (2), and the hydraulic control module (3) respectively, and assemble them together by defining the contact relationship between the contacting components; S2. Define the material properties of the finite element model: Define the elastic modulus E, Poisson's ratio μ, and thermal expansion coefficient α of the materials of the finite element models of each component; S3. Apply the boundary conditions of the finite element model: The boundary conditions include two types. One is to fix the bolt holes of the split housing connected to the engine flywheel housing to simulate the support of the flywheel housing to the transmission. The other is to fix the rotational degrees of freedom of each gear shaft and the differential housing (24) around their respective axis lines; S4. Define the initial temperature of the finite element model: Apply the initial temperature to the split housing, the input shaft (21), the intermediate shafts, the differential housing (24), the bearings, the snap rings, the gasket (51), the gears, the bolts (1), the side cover (2), and the hydraulic control module (3). The initial temperature is defined as the room temperature; S5. Apply Load 1: Load 1 is the bolt pre-tightening force, which is obtained from the relationship between the bolt pre-tightening force and the bolt tightening torque, and then applied to the bolts (1); S6. Apply Load 2: Load 2 is the temperature load, that is, apply a high temperature load to the split housing, the input shaft (21), the intermediate shafts, the differential housing (24), the bearings, the snap rings, the gasket (51), the gears, the bolts (1), the side cover (2), and the hydraulic control module (3). The applied temperatures are the same, and the temperature value is greater than the normal operating temperature value of the transmission; S7. Apply Load 3: Load 3 is the gear meshing force when the transmission is in any forward gear. The gear meshing force is obtained according to the torque M transmitted by the gear shaft, the gear meshing parameters, and the gear load calculation formula, and then applied to the gears that the forward gear torque passes through; S8. Apply Load 4: Load 4 is the gear meshing force when the transmission is in reverse. The gear meshing force is obtained according to the torque M transmitted by the gear shaft, the gear meshing parameters, and the gear load calculation formula, and then applied to the gears that the reverse gear torque passes through; S9. Define the calculation conditions Calculation condition 1: It includes the boundary conditions in step S3, the initial temperature in step S4, Load 1 in step S5, Load 2 in step S6, and Load 3 in step S7; Calculation condition 2: It includes the boundary conditions in step S3, the initial temperature in step S4, Load 1 in step S5, Load 2 in step S6, and Load 4 in step S8; S10. Conduct finite element analysis: According to the order of Calculation condition 1 and Calculation condition 2 defined in step S9, calculate the contact pressure on the surface of the bearing housing (111) in contact with the outer ring of the bearing in sequence; S11. Determination of the position of the bearing housing groove: Linearly superpose the surface contact pressure of the bearing housing (111) obtained in calculation condition 1 in step S10 and the surface contact pressure of the bearing housing (111) obtained in calculation condition 2 to obtain the overall distribution of the surface contact pressure of the bearing housing (111), and select the area with a smaller contact pressure to open the groove of the bearing housing (111). S12. Build a finite element model of the transmission housing assembly based on the bearing housing with a groove and perform finite element analysis: Repeat steps S1 - S10 to calculate the stress magnitude of the bearing housing (111). If the stress of the groove of the bearing housing (111) is less than the allowable stress, it indicates that the position of the opened groove has a good effect; otherwise, it is necessary to repeat step S11 and re - select the position with a smaller contact pressure of the bearing housing (111) to open the groove until the stress of the groove of the bearing housing (111) is less than the allowable stress.

2. The method for determining the groove position of a transmission bearing seat according to claim 1, wherein: In step S1, the mesh nodes on the outer surface of the bearing outer ring correspond one - to - one with the mesh nodes on the inner surface of the split - type housing bearing seat in contact with it. The gears supported by the input shaft and the input shaft (21), the gears supported by the intermediate shaft and the intermediate shaft, and the gears supported by the differential housing (24) and the differential housing (24) are connected together by the co - node method. The bearing and the bearing housing (111) have a zero - clearance fit.

3. A method for determining the groove position of a transmission bearing seat according to claim 1, characterized in that: In step S3, to fix the rotational degrees of freedom of the gear shaft and the differential housing, the RBE3 element is needed. The from - point of the RBE3 element is defined on the axis line. The master - point is selected as the nodes on a cross - section of the gear shaft and the differential housing (24). This cross - section is located between the bearing and the gear. The rotational degree of freedom of the from - point of the RBE3 element around the axis line is constrained. An RBE3 element needs to be established between each gear and the bearing, and the rotational degrees of freedom of all from - points of the RBE3 elements around the axis line are fixed.

4. A method for determining the groove position of a transmission bearing seat according to claim 1, characterized in that: In step S5, the bolt pre - tightening force is calculated using formula (1), and the acting direction is along the axial direction of the bolt. In the formula, F is the bolt pre - tightening force, T is the bolt tightening torque, k is the bolt tightening torque coefficient, and D is the bolt diameter.

5. The method for determining the position of the groove of the transmission bearing seat according to claim 1, characterized in that: In step S7, the number of forward gears included should be the least to shorten the calculation cycle. The number of forward gears included should at least enable the input shaft assembly, the intermediate shaft assembly, and the differential assembly to transmit torque once. The number of forward gears included should be determined in sequence from the first gear to the highest gear.

6. A method for determining the groove position of a transmission bearing seat according to claim 1, characterized in that: According to the method for determining the position of the groove of the transmission bearing housing according to claim 1, characterized in that in steps S7 - S8, the meshing forces of each gear are decomposed into circumferential force, radial force, and axial force, which are calculated using formula (2), and are applied by means of a local cylindrical coordinate system defined on the axis line of each gear shaft. The Z - axis of the coordinate system is along the axis line of the gear shaft, R is along the radial direction of the gear shaft, and t is determined by the right - hand rule according to Z and R. In the formula, F t , F r , F a are respectively the circumferential force, radial force and axial force of the gear, M is the torque transmitted by the gear, d is the pitch circle diameter of the gear, α n is the normal pressure angle of the gear, and β is the helix angle at the pitch circle of the gear; Circumferential force F of the gear t , Radial force F r and Axial force F a are applied to the gear meshing nodes by means of RBE3 elements. The slave points of the RBE3 elements select the gear meshing nodes, and the master points of the RBE3 elements select the tooth surface unit nodes of at least 2 teeth near the gear meshing nodes.

7. A method for determining the position of a groove in a transmission bearing seat according to claim 1, characterized in that: In step S9, calculation condition 1 is based on the number of gears determined in step S7, and calculation condition 2 is based on the number of gears determined in step S8, and is further divided into sub - calculation conditions, that is, one gear corresponds to one sub - calculation condition.

8. A method for determining the groove position of a transmission bearing seat according to claim 1, characterized in that: In step S11, the area with zero contact pressure in the overall distribution of the surface contact pressure of the bearing housing (111) is determined as the position of the groove of the bearing housing (111).

9. The method for determining the position of the groove of the transmission bearing seat according to claim 1, wherein: In the step S12, the allowable stress is the yield strength of the material.

Images