Calculation method for testing the input shaft rotation angle of a gearbox in new energy vehicles.

Abstract

This invention discloses a calculation method for testing the input shaft rotation angle of a gearbox in a new energy vehicle, comprising the following steps: 1) determining the front-wheel-drive new energy vehicle structure; 2) calculating the input shaft rotation angle θ1 caused by the normal backlash of the first-stage gear, the rotation angle θ2 caused by the normal backlash of the second-stage gear, the input shaft rotation angle θ3 caused by the center distance deviation of the first-stage gear, the input shaft rotation angle θ4 caused by the center distance deviation of the second-stage gear, the rotation angle θ5 caused by the axial movement of the half-shaft gear, the rotation angle θ6 caused by the spline backlash of the half-shaft spline, and the rotation angle θ7 caused by the input shaft spline; 3) theoretically calculating the total input shaft rotation angle: fixing the output shaft with a tooling fixture and applying positive and negative torques to the input shaft end. This invention, by fixing both ends of the differential, controls the theoretical backlash of the input shaft to be consistent with the actual test, thereby achieving the target of the OEM.

Description

Technical Field

[0001] This invention relates to the field of automotive gearbox technology, and in particular to a calculation method for testing the input shaft rotation angle of a gearbox in a new energy vehicle. Background Technology

[0002] With the development of new energy technologies, the rapid acceleration and deceleration of the input shaft of new energy gearboxes has become the norm. The restrictions on the rotation angle at the fixed output shaft and input shaft are increasing. Meeting the input shaft rotation angle requirements proposed by the OEM at the initial design stage has become a common practice.

[0003] In practical applications, due to numerous influencing factors, there is currently no complete set of theoretical calculation methods to judge the indicators proposed by the OEM at the beginning of the design project. The only way is to fix two output half-shaft gears on the test bench after the prototype is made, so as to apply torque at the input end and judge the corresponding interval formed by the curve displayed on the oscilloscope. This greatly affects the project cycle or makes the promised indicators of the project incorrect, causing complaints from the OEM or project failure.

[0004] When working with the new OEM, it was proposed that when the pure electric vehicle is accelerating or decelerating rapidly and switching between the active and passive gear surfaces, the gear clearance in the reducer should not exceed the OEM's standard. This would control the risk of slight vibration and noise in the vehicle caused by poor gear meshing when changing the direction of gear rotation. Summary of the Invention

[0005] This invention provides a calculation method for testing the input shaft rotation angle of a new energy vehicle gearbox. After fixing both ends of the differential, the theoretical backlash of the input shaft is controlled to be consistent with the actual test, thereby achieving the goal of the OEM.

[0006] The technical solution to the above problem is as follows:

[0007] A method for calculating the input shaft rotation angle of a gearbox in a new energy vehicle, characterized by the following steps:

[0008] 1) Determine the front-wheel-drive new energy structure;

[0009] 2) Calculate the input shaft rotation angle θ1 caused by the normal backlash of the first-stage gear, calculate the rotation angle θ2 of the second-stage driving gear caused by the normal backlash of the second-stage gear, calculate the input shaft rotation angle θ3 caused by the center distance deviation of the first-stage gear, calculate the input shaft rotation angle θ4 caused by the center distance deviation of the second-stage gear, calculate the rotation angle θ5 caused by the axial movement of the half-shaft gear, calculate the rotation angle θ6 caused by the spline backlash of the half-shaft spline, and calculate the rotation angle θ7 caused by the spline of the input shaft.

[0010] 3) Theoretical calculation of the total rotation angle of the input shaft: Fix the output shaft with a fixture, and apply positive and negative torques to the end of the input shaft. The formula for the total rotation angle formed at the input shaft is as follows:

[0011]

[0012] Among them, Z2 and Z4 are the number of teeth of the first and second stage passive teeth, respectively; Z1 and Z3 are the number of teeth of the first and second stage active teeth, respectively.

[0013] This invention, after fixing both ends of the differential, controls the theoretical backlash of the input shaft to be consistent with the actual test. At the same time, it considers the influence of applied positive and negative torque, thereby making an accurate judgment on the distance between the product and the target. Taking into account the main relevant factors, it uses theoretical calculation methods to transform the relevant backlash factors at each level into the rotation angle of the input shaft, thereby controlling the relevant factors with significant influence at the beginning of the design, and thus making an accurate judgment on the target of the OEM, thereby achieving the OEM's goal. Attached Figure Description

[0014] Figure 1 This is a flowchart of the present invention;

[0015] Figure 2 This is a schematic diagram of the various corners inside the gearbox;

[0016] Figure 3 The theoretical test results for the input shaft rotation angle at ±10 Nm;

[0017] Figure 4 The theoretical test results for the input shaft rotation angle at ±15 Nm;

[0018] Figure 5 The theoretical test results are for the input shaft rotation angle at ±30 Nm. Detailed Implementation

[0019] like Figure 1 and Figure 2 As shown, the calculation method for the input shaft rotation angle test of the new energy vehicle gearbox of the present invention includes the following steps:

[0020] 1) Determine the front-wheel drive new energy vehicle structure. The common front-wheel drive new energy vehicle structure consists of two pairs of meshing gears and a differential.

[0021] 2) Calculate the input shaft rotation angle θ1 caused by the normal backlash of the first-stage gear; calculate the rotation angle θ2 of the second-stage driving gear caused by the normal backlash of the second-stage gear; calculate the input shaft rotation angle θ3 caused by the center distance deviation of the first-stage gear; calculate the input shaft rotation angle θ4 caused by the center distance deviation of the second-stage gear; calculate the rotation angle θ5 caused by the axial movement of the half-shaft gear; calculate the rotation angle θ6 caused by the spline backlash of the half-shaft spline; and calculate the rotation angle θ7 caused by the spline of the input shaft. Additionally, the purpose of applying force at the input shaft is to eliminate various design clearances. If a large force is applied at the input shaft, the impact of deformation on the actual results must be considered. Therefore, when evaluating the results, it is necessary to pay attention to whether the applied force is excessive.

[0022] 3) Theoretical calculation of the total rotation angle of the input shaft: Fix the output shaft with a fixture, and apply positive and negative torques to the end of the input shaft. The formula for the total rotation angle formed at the input shaft is as follows:

[0023]

[0024] Among them, Z2 and Z4 are the number of teeth of the first and second stage passive teeth, respectively; Z1 and Z3 are the number of teeth of the first and second stage active teeth, respectively.

[0025] Preferably, the input shaft rotation angle θ1 caused by the normal backlash of the first-stage gear is calculated using the following formula:

[0026]

[0027] Where: j bn1 The normal backlash of the first-stage gear is the minimum distance between the non-working tooth surfaces when the gear pair is working. θ1 is the angle at which the driving gear can rotate when the first-stage driven gear is fixed. m n1 Z1 is the module of the first-stage gear, Z1 is the number of teeth of the driving tooth in the first-stage gear, and α is the number of teeth of the driving tooth in the first-stage gear. n1 This is the normal pressure angle of the first-stage gear.

[0028] Preferably, the rotation angle θ2 of the second-stage driving tooth caused by the normal backlash of the second-stage gear is calculated using the following formula (3). At the same time, if it is to be converted to the input shaft rotation angle, it is also necessary to multiply it by the speed ratio of the first-stage gear.

[0029]

[0030] Where: j bn2 For the normal backlash of the second-stage gear, m n2 Z3 is the module of the second-stage gear, Z3 is the number of teeth of the driving tooth in the second-stage gear, and α is the number of teeth of the driving tooth in the second-stage gear. n2 This is the normal pressure angle of the second-stage gear.

[0031] Preferably, the calculation of the input shaft rotation angle θ3 caused by the deviation of the center distance of the first-stage gear takes into account the following factors:

[0032] The center distance tolerance of the housing adopts positive and negative tolerances. Through this tolerance, the ideal center distance will be increased or decreased, and thus the side clearance will increase or decrease. When calculating the maximum value of the input shaft rotation angle, the maximum value is selected for verification.

[0033] The center distance position tolerance of the bearing bore is 0.06, assuming the center distance tolerance A... a1 The backlash correction Δj for the first-stage gear caused by the center distance tolerance of the gearbox housing is 0.05 mm. a1 Calculate using the following formula:

[0034]

[0035] Where A a1 Center distance of the first-stage gear, β1; Helix angle of the first-stage gear, α. n1 Normal pressure angle of the first-stage gear;

[0036] The input shaft rotation angle θ3 caused by the center distance deviation is calculated using the following formula:

[0037]

[0038] Where D11 is the pitch circle diameter of the driving tooth of the first-stage gear, and its calculation formula is as follows:

[0039]

[0040] Z1 is the number of teeth on the driving gear in the first stage, and Z2 is the number of teeth on the driven gear.

[0041] Preferably, according to formula (4), the secondary gear generates a clearance correction amount Δj through the center distance of the gearbox. a2 Calculate using the following formula:

[0042]

[0043] Among them: A a2 β2 is the center distance of the second-stage gear; α is the helix angle of the second-stage gear. n2 The normal pressure angle of the second-stage gear;

[0044] The input shaft rotation angle θ4 caused by the center distance deviation of the second-stage gear is calculated as follows:

[0045] Perform the following formula:

[0046]

[0047] Where D21 is the pitch circle diameter of the driving tooth of the second-stage gear, and its calculation formula is as follows:

[0048]

[0049] Where Z4 is the number of teeth of the driven teeth in the second-stage gear;

[0050] When converted to the input shaft rotation angle, the input shaft rotation angle θ4 caused by the deviation of the center distance of the second-stage gear is multiplied by the speed ratio of the first-stage gear.

[0051] Preferably, to enhance the strength of the bevel gear, improve the tooth surface fit, and reduce noise, flat shims are typically used to control the axial movement of the bevel gear. The axial movement Δ1 of the bevel gear will cause a corresponding normal backlash J on the bevel gear tooth surface. bn3 The change in axial movement of the bevel gear. To eliminate the normal backlash on the bevel gear tooth surface, the half-shaft gear needs to rotate by a certain angle θ5. The calculation of the rotation angle θ5 caused by the axial movement of the half-shaft gear is as follows:

[0052] (a) Normal backlash J caused by cross movement of the axle gear end face bn3 Perform the following formula:

[0053] J bn3 =2*Δ1*sinδ*tanΦ.............................(10)

[0054] Where: b n3 Δ1 is the normal backlash of the bevel gear, Δ1 is the axial movement of the half-shaft gear, δ is the pitch cone angle of the half-shaft gear, which is equal to the ratio of the number of teeth of the half-shaft gear to the number of teeth of the planetary gear, and Φ is the pressure angle of the half-shaft gear.

[0055] (b) Normal backlash of the half-shaft gear J bn3 Circumferential clearance J w3 Relationship between them:

[0056]

[0057] (c) Circumferential backlash of the half-shaft gear J w3 The relationship between the angle θ5 caused by the rotation:

[0058]

[0059] J w3 R is the circumferential backlash of the half-shaft gear, and R is the circumferential radius of the bevel gear.

[0060] The rotation angle caused by the axial movement of the half-shaft gear is converted to the input shaft and then multiplied by the product of the first-stage speed ratio and the second-stage speed ratio.

[0061] Preferably, (a) the rotation angle θ6 caused by the spline backlash of the half-shaft spline, and the rotation angle θ7 caused by the input shaft spline are calculated according to the following formula:

[0062]

[0063]

[0064] Where: θ6 is the rotation angle caused by the half-shaft spline, θ7 is the rotation angle caused by the input shaft spline, Δ1 is the side clearance value of the half-shaft spline, Δ3 is the side clearance value of the input shaft spline, and D6 and D7 are the pitch circle diameters of the half-shaft spline and the input shaft spline, respectively;

[0065] (b) When converting the rotation angle θ6 caused by the spline backlash of the half shaft to the input shaft rotation angle, multiply it by the product of the first-stage speed ratio and the second-stage speed ratio.

[0066] The following examples illustrate this point:

[0067] Theoretical calculations. In a certain new energy project, the OEM requires that the rotation angle of the input shaft be adjusted under a certain positive and negative symmetrical torque with two fixed half-shaft gears. The relevant input parameters are shown in Table 1:

[0068] Table 1 Input Parameters

[0069]

[0070] After verifying the relevant input parameters using all the formulas in step 3), the theoretical results of the shaft rotation angle calculation are shown in Table 2 below:

[0071] Table 2. Example of Calculation of Axial Backlash Caused by Axial End Clearance of Half-Shaft Gear

[0072]

[0073] Table 3 Theoretical results of input shaft rotation angle calculation

[0074]

[0075] Considering factors related to the reducer's own backlash, the theoretically designed maximum input shaft rotation angle of this gearbox is 11.2746°. The top three influencing factors are: half-shaft spline backlash, bevel gear axial movement, and secondary gear backlash, with the speed ratio having the most significant impact. If the force applied to the input end is too large, the deformation at the half-shaft gear will also increase, ultimately affecting the actual magnitude of the input shaft rotation angle.

[0076] Actual test results

[0077] A bench test was conducted for a certain project. The motor torque was connected to the input shaft through a sensor, universal joint, base, and the sensor signal included torque signal and angle signal.

[0078] Actual test results: Under various torques, the measured sample's theoretical backlash-induced rotation angle was 8.5°-9.5°, within the calculated theoretical input shaft rotation angle range of 5.5377-11.2746 degrees. Furthermore, under actual torques of ±10NM, ±15NM, and ±30NM, the final input shaft rotation angles were approximately 14°, 17°, and 22°, respectively, indicating that the influence of torque deformation on the input shaft rotation angle gradually increases with increasing torque.

[0079] Therefore, at the beginning of this project, it was combined with Figures 3 to 5 Before the prototype was developed, the OEM's requirement that the backlash angle at the input shaft positions of the fixed differential be 15° under ±30 N·m was unreasonable, because the actual design clearance inside the reducer had already been eliminated under ±10 N·m. Therefore, based on this theoretical verification method, the OEM agreed to adjust its development requirements to: fix the half-shaft gears on both sides of the differential with external splines of the tooling, thereby applying a torque of ±10 N·m at the input shaft, requiring that the input shaft angle change range be 15° from -10 N·m to +10 N·m.

[0080] In the later stages of project development, due to the similar structure, the requirements put forward by the OEM can be pre-calculated and judged according to the method specified in this patent.

[0081] The embodiments described in this invention are some, but not all, of the embodiments of this invention. The embodiments described with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be simply construed as limiting the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention.

Claims

1. A calculation method for testing the input shaft rotation angle of a gearbox in a new energy vehicle, characterized in that, The following steps are involved: 1) Determine the front-wheel-drive new energy structure; 2) Calculate the input shaft rotation angle θ1 caused by the normal backlash of the first-stage gear, calculate the rotation angle θ2 of the second-stage driving gear caused by the normal backlash of the second-stage gear, calculate the input shaft rotation angle θ3 caused by the center distance deviation of the first-stage gear, calculate the input shaft rotation angle θ4 caused by the center distance deviation of the second-stage gear, calculate the rotation angle θ5 caused by the axial movement of the half-shaft gear, calculate the rotation angle θ6 caused by the spline backlash of the half-shaft spline, and calculate the rotation angle θ7 caused by the spline of the input shaft. 3) Theoretical calculation of the total rotation angle of the input shaft: Fix the output shaft with a fixture, and apply positive and negative torques to the end of the input shaft. The formula for the total rotation angle formed at the input shaft is as follows: Among them, Z2 and Z4 are the number of teeth of the first and second stage passive teeth, respectively; Z1 and Z3 are the number of teeth of the first and second stage active teeth, respectively. The calculation of the input shaft rotation angle θ3 caused by the center distance deviation of the first-stage gear takes the following factors into consideration: The center distance tolerance of the housing adopts positive and negative tolerances. Through this tolerance, the ideal center distance will be increased or decreased, and thus the side clearance will increase or decrease. When calculating the maximum value of the input shaft rotation angle, the maximum value is selected for verification. The center distance positional tolerance of the bearing bore is 0.06 mm. Assuming the center distance tolerance is 0.05 mm, the backlash correction Δj of the first-stage gear caused by the center distance tolerance of the housing is calculated. a1 Calculate using the following formula: Where A a1 β1 is the center distance of the first-stage gear, β1 is the helix angle of the first-stage gear, and α is the center distance of the first-stage gear. n1 The normal pressure angle of the first-stage gear; The input shaft rotation angle θ3 caused by the deviation in the center distance of the first-stage gear is calculated using the following formula: Where D 11 The formula for calculating the pitch circle diameter of the primary gear's driving tooth is as follows: Z1 is the number of teeth of the driving teeth in the first-stage gear, and Z2 is the number of teeth of the driven teeth in the second-stage gear; The calculation of the rotation angle θ5 caused by the axial movement of the half-shaft gear is performed as follows: Normal backlash J caused by end face movement of half-shaft gear bn3 Perform the following formula: J bn3 =2*Δ1*sinδ*tanΦ...............................(10) Where: bn3 is the normal backlash of the bevel gear, △1 is the axial movement of the half-shaft gear, δ is the pitch cone angle of the half-shaft gear, which is equal to the ratio of the number of teeth of the half-shaft gear to the number of teeth of the planetary gear, and Φ is the pressure angle of the half-shaft gear; Half-shaft gear normal backlash J bn3 Circumferential clearance J w3 Relationship between them: Circumferential backlash J of half-shaft gear w3 The relationship between the angle θ5 caused by the rotation: J w3 R is the circumferential backlash of the half-shaft gear, and R is the circumferential radius of the bevel gear; The rotation angle caused by the axial movement of the half-shaft gear is converted to the input shaft and then multiplied by the product of the first-stage speed ratio and the second-stage speed ratio.

2. The calculation method for the input shaft rotation angle test of the new energy vehicle gearbox according to claim 1, characterized in that, The input shaft rotation angle θ1 caused by the normal backlash of the first-stage gear is calculated using the following formula: Where: j bn1 The normal backlash of the first-stage gear is the minimum distance between the non-working tooth surfaces when the gear pair is working. θ1 is the angle at which the driving gear can rotate when the first-stage driven gear is fixed. m n1 Z1 is the module of the first-stage gear, Z1 is the number of teeth of the driving tooth in the first-stage gear, and α is the number of teeth of the driving tooth in the first-stage gear. n1 This is the normal pressure angle of the first-stage gear.

3. The calculation method for the input shaft rotation angle test of the new energy vehicle gearbox according to claim 1, characterized in that, The rotation angle θ2 of the second-stage active tooth caused by the normal backlash of the second-stage gear is calculated using the following formula (3). At the same time, if it is to be converted to the input shaft rotation angle, it is also necessary to multiply it by the speed ratio of the first-stage gear. Where: j bn2 For the normal backlash of the second-stage gear, m n2 Z3 is the module of the second-stage gear, Z3 is the number of teeth of the driving tooth in the second-stage gear, and α is the number of teeth of the driving tooth in the second-stage gear. n2 This is the normal pressure angle of the second-stage gear.

4. The calculation method for the input shaft rotation angle test of the new energy vehicle gearbox according to claim 1, characterized in that, According to formula (4), the clearance correction amount Δj of the secondary gear is generated by the center distance of the gearbox. a2 Calculate using the following formula: Among them: A a2 β2 is the center distance of the second-stage gear; α is the helix angle of the second-stage gear. n2 The normal pressure angle of the second-stage gear; The input shaft rotation angle θ4 caused by the center distance deviation of the second-stage gear is calculated as follows: Perform the following formula: Where D 21 The formula for calculating the pitch circle diameter of the driving tooth of the second-stage gear is as follows: Where Z4 is the number of teeth of the driven teeth in the second-stage gear; When converted to the input shaft rotation angle, the input shaft rotation angle θ4 caused by the deviation of the center distance of the second-stage gear is multiplied by the speed ratio of the first-stage gear.

5. The calculation method for the input shaft rotation angle test of the new energy vehicle gearbox according to claim 1, characterized in that, (a) The rotation angle θ6 caused by the spline backlash of the half-shaft spline, and the rotation angle θ7 caused by the input shaft spline are calculated according to the following formula: Where: θ6 is the rotation angle caused by the half-shaft spline, θ7 is the rotation angle caused by the input shaft spline, Δ2 is the side clearance value of the half-shaft spline, Δ3 is the side clearance value of the input shaft spline, and D6 and D7 are the pitch circle diameters of the half-shaft spline and the input shaft spline, respectively; (b) When converting the rotation angle θ6 caused by the spline backlash of the half shaft to the input shaft rotation angle, multiply it by the product of the first-stage speed ratio and the second-stage speed ratio.

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