CN104217047A - Method for manufacturing envelope face of automobile front steering wheel - Google Patents

Abstract

The invention provides a method for making the envelope surface of the front steering wheel of the automobile, comprising: generating the motion trajectory file of the front steering wheel according to the wheel jump and steering final coupling relationship curve of the front steering wheel of the automobile; Wheel tire model, make the static model of tire profile; Set up a motion simulation model that only contains described wheel profile, make the corresponding coordinate value on the described wheel tire profile change according to the track curve in the motion track file of described front steering wheel, The wheel is simulated to move, and the envelope volume sweep is performed on its motion space to obtain the motion envelope surface of the wheel. The envelope surface obtained by the invention has high reliability and safety, can improve design efficiency, and reduces design risk and development cost.

Description

A method for making the envelope surface of the front steering wheel of the automobile

technical field

The invention relates to the technical field of automobiles, in particular to a method for manufacturing an envelope surface of an automobile front steering wheel.

Background technique

The vehicle's wheel motion envelope refers to the movement space occupied by the wheel tires during the process of the wheels bouncing up and down with the suspension and turning to each limit position under various driving conditions of the vehicle. It determines the opening shape of the wheel cover and the fender, and can also be used to check the dynamic clearance and motion interference between the wheel and the surrounding subsystems and components, and may even drive the wheel track, Adjustment of the minimum turning radius of the vehicle, etc. Therefore, in the development stage of the vehicle project, analyzing and designing a more accurate wheel package at an appropriate development node plays an important role and significance in reducing design risks, reducing later design changes, shortening the development cycle, and reducing development costs.

The motion envelope of the wheel is determined by the motion mechanism of the wheel, and its influencing factors include: suspension system topology (suspension type), geometry (suspension system hard point), wheel jump and steering relationship, wheel alignment parameters, tire type, tire static profile standard and snow chain application strategy, etc.

At present, automotive engineers usually use simulation software to simulate and analyze the motion of the suspension system in the development and design stage, and simulate and calculate the space occupied by the wheel jumping motion in the vertical direction and the steering motion rotating around the kingpin axis. This will make the wheel envelope. However, in the suspension system, the upper part of the shock absorber, the lower control arm and the body are connected by rubber bushings, which is a multi-flexible body system. However, in the general suspension motion simulation, a simple rigid body kinematics model is often used, ignoring the mechanism displacement caused by the force deformation of flexible components such as rubber bushings in the system, and the motion trajectory of the wheel cannot be accurately simulated. The wheel pack results don't map very well to reality.

Therefore, there is currently no method for generating an envelope of wheel motion that can accurately simulate wheel motion trajectories.

Contents of the invention

The technical problem to be solved by the present invention is that the present invention proposes a method for manufacturing the envelope surface of the front steering wheel of the automobile, which can reflect the precise movement trajectory of the wheel and make the generated wheel envelope surface smooth and complete.

In order to solve the above-mentioned technical problems, an aspect of the embodiments of the present invention provides a method for making an envelope surface of a front steering wheel of an automobile, comprising the following steps:

According to the wheel jump and steering final coupling relationship curve of the front steering wheel of the automobile, the tire envelope surface simulation analysis is carried out by the first dynamic simulation software, and the motion track file of the front steering wheel is generated;

Make a static model of the tire profile according to the selected wheel tire model;

According to the static model of the wheel and tire profile made, in the second kinematics simulation software, a motion simulation model containing only the wheel profile is established, and a fixed coordinate system is established according to the design requirements of the whole vehicle, and the origin and coordinates of the coordinate system are The axis direction is the same as that of the whole vehicle;

Create appropriate kinematic pairs and drives on the wheel, so that the pose of the wheel is completely determined by the coordinates of the center point of the wheel and the fixed point on the central axis;

Edit the law of motion curve to make the corresponding coordinate values on the tire contour of the wheel change according to the trajectory curve in the motion trajectory file of the front steering wheel, so that the wheel performs simulated motion, and sweeps the envelope of its motion space, The envelope of motion of the wheel is obtained.

Wherein, the final coupling relationship curve includes a plurality of coordinate points, and each coordinate point includes a wheel jump travel parameter and a steering rack travel parameter.

Wherein, the movement trajectory file of the front steering wheel at least includes: at each moment in the simulation experiment process, the movement trajectory of the x, y, z coordinates of the wheel center point of the front steering wheel, and the relationship between the center axis of the wheel and the wheel The trajectory of the x, y, z coordinates of a point whose center distance is a fixed value.

Wherein, the step of making a static model of the tire profile further includes:

Making a static model of the tire profile of the tire under normal working conditions, braking working conditions and accelerating working conditions.

Wherein, the static model of making the tire profile of the tire under general working conditions is specifically:

According to the ETRTO standard, the cross-sectional shape diagram of a certain type of tire is obtained, and the cross-sectional shape of the tire is rotated around the center line to obtain the static model of the tire profile.

Wherein, the static model of making the tire profile of the tire under braking conditions is specifically:

According to the ETRTO standard, obtain the cross-sectional shape diagram of a certain type of tire;

Taking the centerline of the wheel as the axis, rotating the cross-sectional shape of the tire by 180° from the positive direction of the Y-axis to the negative direction of the Y-axis to form the first part of the final size of the tire model;

Translate the centerline of the wheel along the positive direction of the X coordinate by a radial deformation amount to form the axis P, and use P as the axis to rotate the tire section from the positive direction of the Y axis to the negative direction of the Y axis by 180° to form the second part of the final size of the tire model;

Translate the tire section from the centerline to P to form the third part of the final size of the tire model;

Combining the three parts, a static model of the tire profile under braking conditions is obtained.

Wherein, the static model of making the tire profile of the tire under accelerated working conditions is specifically:

According to the ETRTO standard, obtain the cross-sectional shape diagram of a certain type of tire;

Taking the centerline of the wheel as the axis, rotating the cross-sectional shape of the tire by 180° from the positive direction of the Y-axis to the negative direction of the Y-axis to form the first part of the final size of the tire model;

Translate the centerline of the wheel along the negative direction of the X-axis by a radial deformation amount to form the axis P, and use P as the axis to rotate the tire section from the positive direction of the Y-axis to the negative direction of the Y-axis by 180° to form the second part of the final size of the tire model;

Translate the tire section from the centerline to P to form the third part of the final size of the tire model;

Combining the three parts, a static model of the tire profile under braking conditions is obtained.

Wherein, the step of changing the corresponding coordinate values on the wheel tire contour according to the trajectory curve in the motion trajectory file of the front steering wheel is specifically:

At least make the x, y, z coordinate values of the center point of the static model of the wheel profile and the x, z coordinate values of a point on the central axis with a fixed distance from the center point according to the motion track file of the front steering wheel The corresponding trajectory movement in .

Among them, further include:

According to the manufactured tire enveloping surface of the front steering wheel of the automobile, the interference relationship between it and the surrounding parts of the tire is simulated.

Wherein, the first kinematics simulation software is ADAMS/Car software; the second kinematics simulation software is CATIA/DMU software.

Implement the present invention, have following beneficial effect:

In the embodiment of the present invention, the motion of the wheel is only determined by the coordinates of the center of the wheel and the coordinate motion trajectory of a point on the central axis. Compared with the prior art, the motion of the wheel no longer depends on the motion of the suspension and the steering mechanism. Therefore, using this technical solution to make the wheel envelope surface, only one kinematic model of the wheel needs to be established, which can be applied to all models, and there is no need to input the suspension geometric topology and hard point information of the model, which greatly improves the work efficiency;

The motion enveloping surface obtained by this method takes into account factors such as the elastic deformation of the vehicle under complex working conditions, the manufacturing and use errors of the tire, and the like. Using the wheel envelope surface obtained by this method, the gap between the wheel and surrounding components, especially the wheel cover, can be measured and checked. The obtained results have high reliability and safety, and solve the problem of simple rigid body model simulation and real vehicle test. The problem of large errors reduces the design risk, shortens the development cycle of the vehicle project, and reduces the development cost of the vehicle.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the main flow chart of a kind of method that makes the envelope surface of steering wheel before automobile provided by the present invention;

Fig. 2 is a schematic diagram of the motion trajectory of the front steering wheel center point X coordinate obtained in a method for making the envelope surface of the front steering wheel of an automobile provided by the present invention;

Fig. 3 is a schematic diagram of the trajectory of the Y coordinates of the center point of the front steering wheel obtained in a method for making the envelope surface of the front steering wheel of an automobile provided by the present invention;

Fig. 4 is a schematic diagram of the trajectory of the Z coordinate of the center point of the front steering wheel obtained in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 5 is a schematic diagram of the movement track of a fixed point X coordinate on the central axis of the front steering wheel obtained in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 6 is a schematic diagram of the movement track of a fixed point Y coordinate on the central axis of the front steering wheel obtained in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 7 is a schematic diagram of the movement track of a fixed point Z coordinate on the central axis of the front steering wheel obtained in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 8 is a sectional view of the first tire CAD model adopted in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 9 is a sectional view of the second tire CAD model adopted in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 10 is a schematic diagram of the outline of the wheel under special working conditions obtained by using the tire CAD model sectional view of Fig. 9 in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 11 is a flow chart of obtaining the final coupling relationship curve in an embodiment of the method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 12 is a schematic diagram of the suspension Roof figure of an embodiment in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 13 is the schematic diagram of the front wheel Roof of a vehicle in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 14 is the Roof diagram of the front steering wheel of a vehicle under special working conditions in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Fig. 15 is a schematic diagram of the envelope surface of the front steering wheel obtained in a method for manufacturing the envelope surface of the front steering wheel of an automobile provided by the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

As shown in Figure 1, it is a kind of main flowchart of the method for making the front steering wheel envelope surface of automobile provided by the present invention; It comprises the following steps:

Step S10: According to the pre-acquired wheel jump and steering final coupling relationship curve of the front steering wheel of the car, the tire envelope surface simulation analysis is performed through the first dynamic simulation software, and the motion track file of the front steering wheel is generated, wherein the final The coupling relationship curve includes a plurality of coordinate points, wherein each coordinate point includes a wheel jump stroke parameter and a steering rack stroke parameter. Fig. 13 shows a final coupling relationship curve, and how to obtain the final coupling relationship curve will be described in the following Describe in detail in the text.

According to the final coupling relationship curve between wheel jump and steering of the automobile, the motion track file of the front steering tire can be output through the dynamics simulation software. Carry out the tire envelope (Wheel Envelope) simulation analysis in dynamic simulation software (such as Adams/Car). Through this simulation, the motion trajectory file of the wheel can be generated. These motion trajectory files include the x, y, z coordinates of the center point of the wheel and the x, y, z coordinates of a point on the central axis of the wheel at a fixed distance from the wheel center at each moment during the simulation experiment , an example of the movement track of the six coordinates can be seen in Fig. 2 to Fig. 7 .

Step S12: making a tire CAD model according to the model of the selected wheel tire;

Specifically, it includes: selecting a suitable wheel and tire model according to the needs of the vehicle; making a CAD model of the tire.

Specifically, in one embodiment, the CAD model of the tire is made using the European Tire and Rim Technical Organization (TRTO European Tire and Rim Technical Organization, ETRTO) standard. Among them, each size parameter is obtained by referring to the ETRTO-2010 standard according to the selected tire model. In this standard, the maximum external dimension of the tire model section is the maximum use size, which includes the deformation of the wheel during normal use and the maximum tolerance value of the tire, which not only ensures full consideration of factors such as manufacturing errors of various suppliers, No redundant design. For the specific modeling method, refer to the ETRTO-2010 standard. Figure 8 and Figure 9 show the cross-sectional shapes of two kinds of tires, where the parameters in the tire cross-section in Figure 8 satisfy A+2(B _max +4)>=s _G , while the parameters in the tire cross-section in Figure 9 satisfy The parameters satisfy A+2(B _max +4) <= s _G . The CAD model of the tire is obtained by rotating the cross-sectional shape of the tire in Fig. 8 or Fig. 9 around the center line.

In addition, under special working conditions such as braking or acceleration, it is necessary to consider the radial deformation of the wheel under braking and acceleration. Among them, the radial deformation refers to the displacement of the center point of the wheel in the radial direction under the influence of the ground force and the force deformation of the suspension elastic element, that is, the displacement along the positive direction of the X axis or the negative direction of the X axis quantity. As shown in Figure 10, it is a schematic diagram of the outline of the wheel under special working conditions obtained by using the tire CAD model sectional view of Figure 9 in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention; the outline of the wheel The CAD model is obtained by:

Taking the centerline of the wheel (C.R.) as the axis, rotate the tire section shown in Figure 9 from point A (from the positive direction of the Y axis) to point B (the negative direction of the Y axis) by 180° to form the first part of the final size of the tire model; Under the braking condition, the center line of the wheel (C.R.) is translated along the positive direction of the X-axis by a radial deformation amount (n mm) to form the axis P. Taking P as the axis, the tire section is drawn from point C (from the positive direction of the Y-axis) ) to point D (the negative direction of the Y axis) to rotate 180° to form the second part of the final size of the tire model; under acceleration conditions, the axis P is formed by the radial deformation of the center axis of the wheel along the negative direction of the X axis, and the same Taking P as the axis, rotate the tire section from point C (from the positive direction of the Y axis) to point D (the negative direction of the Y axis) by 180° to form the second part of the final size of the tire model; Translate to P to form the third part of the final size of the tire model; finally, combine these three parts to obtain the wheel CAD model under braking (or acceleration) conditions. Wherein, in one embodiment, the radial deformation of the tire is 10 mm, which is an empirical value. It can be understood that the deformation can also be determined according to CAE simulation results.

Step S14: According to the static model of the wheel profile and combined with the trajectory file of the front steering wheel, the motion envelope surface of the wheel is made:

Since the static CAD model of the wheel profile has been obtained in step S12, in the kinematics simulation software (such as CATIA/DMU) module, a kinematic simulation model containing only the wheel profile is established, and a fixed coordinate system is established according to the vehicle design requirements , the origin of the coordinate system and the direction of the coordinate axes are the same as those set for the vehicle. In the space kinematics analysis, the wheel has 6 degrees of freedom of space movement. Since the rotation of the wheel tire around its central axis does not affect the spatial position it occupies, the position and attitude of the wheel at a certain moment can be determined by an array of 5 independent parameters, which are composed of the steps S10 obtains the x, y, z coordinate values of the center point of the wheel and the x, z coordinate values of a point on the central axis whose distance from the center point is a fixed value. In the kinematics simulation software (such as CATIA/DMU) module, create appropriate kinematic pairs and drives on the wheel, so that the pose of the wheel is completely determined by the coordinates of the center point of the wheel and the fixed point on the central axis. Edit the law of motion curve to make the corresponding coordinates on the static CAD model of the wheel profile change according to the track curve obtained in step S10, so that the wheel can be moved according to the space track in the simulation test in step S10, specifically, make The x, y, and z coordinates of the center point of the static CAD model of the wheel profile and the x, z coordinates of a point on the central axis with a fixed distance from the center point are respectively in accordance with the aforementioned motion trajectory file (Fig. 2-Fig. 7) Trajectory movement in. Sweep the envelope volume (Swept Volume) on the motion space of the wheel outline to obtain a detailed and smooth wheel motion envelope surface, as shown in Figure 15.

In this technical solution, the movement of the wheel is only determined by the coordinate track of the center of the wheel and a point on the central axis. Compared with the prior art, the motion of the wheel no longer depends on the motion of the suspension and the steering mechanism. Therefore, applying this technical scheme to make the wheel envelope surface only needs to establish a kinematic model of the wheel, which can be applied to all models, and does not need to input the suspension geometric topology and hard point information of the model, which greatly improves the work efficiency.

After the wheel motion envelope surface is obtained, the tire motion envelope surface can be used to check the clearance between the wheel and surrounding components.

The flow chart of obtaining the final coupling relationship curve in the above step S10 in one embodiment of the present invention is illustrated below with reference to FIG. 11-FIG. 14 .

As shown in Figure 11, it shows a kind of flow chart that obtains the final coupling relationship curve in an embodiment of the method for making the envelope surface of the front steering wheel of the automobile provided by the present invention; as can be seen therefrom, it comprises the following steps:

Step S110: Obtain the first coupling relationship curve of wheel jump and steering of the front steering wheel of the car, the first coupling relationship curve includes a plurality of coordinate points, and each coordinate point includes a shock absorber travel parameter and a first steering rack travel parameter , wherein, the stroke parameter of the shock absorber at each coordinate point in the first coupling relationship curve is the percentage of the current stroke of the shock absorber to the limit stroke of the shock absorber, and the stroke parameter of the first steering rack is the steering gear The percentage of the current stroke of the bar and the limit stroke of the steering rack, wherein the stroke parameter of the shock absorber is taken as the ordinate note, and the stroke parameter of the first steering rack is taken as the abscissa, wherein the wheel jump of the front steering wheel of the automobile and the first coupling of the steering The relationship curve can be obtained by testing a large number of prototype vehicles in advance;

Step S111: Obtain the second coupling relationship curve of the wheel jump and steering of the front steering wheel considering the deformation of the elastic member through the dynamics simulation software, and the second coupling relationship curve includes coordinate points corresponding to the first coupling relationship curve , and each coordinate point includes wheel jump travel parameters and second steering rack travel parameters, specifically, including:

Establishing the simulation model of the front suspension system of the automobile through dynamics simulation software, including the geometric topology of the suspension system, and bush connections and stiffness characteristics, the connections including ball joints or rubber bushes;

Carry out motion simulation to the front suspension system of the automobile, and make the motion path of the suspension include a plurality of coordinate points, which correspond to the coordinate points in the first coupling relationship curve one by one. During the simulation motion, measure each The distance between the wheel center at the coordinate point and the wheel center along the vertical direction of the ground in the design state is taken as the current wheel jump stroke, and the wheel center at the limit position of the wheel jump up and down when the rigid suspension system is not turning and the design state The distance between the center of the wheel along the vertical direction of the ground is taken as the upper and lower wheel hop limit travel, and the percentage of the current wheel hop travel and the wheel hop limit travel at each coordinate point is calculated and used as the ordinate value, and the current steering rack travel and the steering rack The percentage of the limit stroke is used as the abscissa value to form the second coupling relationship curve;

In addition, in some embodiments, it is necessary to obtain the coupling relationship curve of the wheel jump and steering of the front steering wheels under special working conditions such as braking or acceleration through dynamics simulation software;

Step S112: Combine the first coupling relationship curve and the second coupling relationship curve to obtain the wheel jump and steering final coupling relationship curve of the front steering wheel of the car, wherein each coordinate point on the final coupling relationship curve The wheel jump travel parameter is the larger value of the damping travel parameter of the corresponding coordinate point in the first coupling relationship curve and the wheel jump travel parameter of the corresponding coordinate point in the second coupling relationship curve.

The following description will be made in conjunction with FIG. 12 to FIG. 14 to facilitate a further understanding of the above steps.

As shown in FIG. 12 , it is a schematic diagram of a suspension Roof diagram of an embodiment of a method for manufacturing an envelope surface of an automobile front steering wheel provided by the present invention.

During the running of the car, due to the constraints of the suspension system, the front steering wheel of the car can not only jump up and down, but also turn around the kingpin to achieve steering. Therefore, the motion of the wheel appears as a coupling of wheel hopping and steering. In general, when the car is running, its wheels will not reach the wheel jump limit and the steering limit at the same time. In order to describe the limit position that the wheels of a model may reach, it is necessary to obtain the relationship curve between wheel jump and steering coupling (that is, the so-called first coupling relationship curve mentioned above), and the wheel jump can be calculated by the axial travel of the shock absorber to reflect. Figure 12 shows the first coupling relationship curve between the steering rack stroke and the shock absorber stroke of a certain car, because its shape is similar to the roof shape, so it is also called the roof (Roof) diagram, we put the first The coupling relationship curve is called the suspension Roof diagram. Among them, the axis of abscissa represents the percentage of the current stroke of the steering rack and the limit stroke of the steering rack, reflecting the steering of the wheel; the axis of ordinate represents the percentage of the current stroke of the shock absorber and the limit stroke of the shock absorber, reflecting the up and down beating of the wheel. As can be seen from Figure 12, during the driving of this car, when the steering stroke reaches 100% of the limit stroke, the wheel jump up and down stroke will not exceed 80% of the limit stroke.

Specifically, the suspension Roof diagram can be obtained through a large number of prototype vehicle tests. In the test, the wheel cover is first filled with foam, and the most severe test conditions such as passing through pits, braking, maximum steering and climbing are used on the proving ground to reflect the sports limit of the tire. After the test is completed, the motion profile of the tire is obtained by measuring or doing reverse calculation. On the basis of a large number of test data, combined with the adjustment of simulation analysis and design experience, the Roof diagram of the suspension is finally obtained. In the Roof diagram of the suspension, each coordinate point is composed of two parameters, the two parameters are the shock absorber stroke parameter and the first steering rack stroke parameter, wherein, each coordinate point in the first coupling relationship curve The stroke parameter of the shock absorber is the percentage of the current stroke of the shock absorber and the limit stroke of the shock absorber, and the stroke parameter of the first steering rack is the percentage of the current stroke of the steering rack and the limit stroke of the steering rack.

As shown in Figure 13, it is the front wheel Roof intention of a kind of vehicle in the method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

With the help of dynamic simulation software, considering the motion characteristics of the geometric mechanism of the chassis system and the motion characteristics of elastic parts, the suspension Roof diagram obtained in Figure 12 is adjusted and corrected to obtain the wheel Roof diagram.

The suspension Roof diagram determined in Fig. 12 reflects the coupling relationship between the steering rack stroke and the shock absorber stroke, which does not consider the kinematic characteristics of the elastic parts of the chassis system. In order to design a more accurate front wheel tire envelope, it is also necessary to calculate the wheel jump-steering relationship curve considering the deformation of the elastic parts ( That is, the second coupling relationship curve), and defined as the wheel Roof diagram. The implementation process is specifically:

In the module of dynamic simulation software (eg, ADAMS/Car), establish the simulation model of the front suspension system of the vehicle. The simulation model includes the geometric topology of the suspension system, and the structural parts of the suspension are connected by ball joints or rubber bushes according to the actual vehicle conditions. Among them, the stiffness characteristics of the rubber bushing can be simulated by modifying its attribute file according to the actual measurement results. The simulation based on the dynamics simulation software simulates the geometric motion characteristics of the suspension system and the motion characteristics of the elastic parts, which can be closer to the actual vehicle motion;

The motion simulation of the front suspension system of the vehicle is carried out, and the motion path of the suspension includes multiple coordinate points, and each coordinate point is composed of two parameters of the stroke of the shock absorber and the stroke of the rack. The coordinate points of the simulated motion path need to correspond one-to-one with the coordinate points of the suspension Roof diagram in Figure 12, and the steering rack strokes of the two corresponding coordinate points are consistent. In the simulation motion, measure the distance between the wheel center of each coordinate point and the wheel center in the design state along the vertical direction (z direction) as the current wheel jump stroke. The distance between the wheel center of the rigid suspension system at the limit position of the wheel up and down jump when not turning and the wheel center in the design state along the direction vertical to the ground (z direction) is taken as the limit stroke of the up and down wheel jump. Calculate the percentage of the current wheel jump travel and the wheel jump limit travel of each coordinate point (that is, the wheel jump travel parameter) and use it as the vertical coordinate value, and use the percentage of the steering rack travel and the limit travel (that is, the second steering rack travel parameter) as the horizontal axis. Coordinate values form the simulated wheel Roof diagram as shown in Figure 3.

Finally, integrate the suspension Roof diagram and the simulated wheel Roof diagram, and take the one with the larger absolute value at each coordinate point of the two to generate the final wheel Roof diagram (that is, the final coupling relationship curve). The wheel hopping stroke parameter of each coordinate point on the curve is the shock absorber stroke parameter of the coordinate point in the first coupling relationship curve and the wheel hopping stroke parameter of the corresponding coordinate point in the second coupling relationship curve The larger value of the steering rack stroke parameter of each coordinate point on the final coupling relationship curve is the first steering rack stroke parameter of the corresponding coordinate point of the first coupling relationship curve or the second steering rack stroke parameter of the corresponding coordinate point of the second coupling relationship curve. For the steering rack stroke parameter, it can be understood that the first steering rack stroke parameter and the second steering rack stroke parameter are equal at the corresponding coordinate points.

Since the dynamics simulation performed in the dynamics simulation software includes the properties of elastic elements such as rubber bushings, the final wheel Roof diagram obtained combines the kinematic characteristics of its rigid mechanism and the elastic mechanical characteristics of elastic components. Make the simulated movement closer to the real condition of the car.

As shown in Figure 14, it is the Roof intention of the front steering wheel of a vehicle under special working conditions in a method for making the envelope surface of the front steering wheel of the automobile provided by the present invention;

Under special working conditions such as braking or accelerating, the movement space of the wheels will change. Figure 14 shows the special Roof diagram of the car under braking or accelerating working conditions (that is, the wheel of the front steering wheel under special working conditions). Jump and steering coupling relationship curve), this special Roof diagram can be obtained by combining simulation analysis and experience on the basis of prototype test data under special working conditions.

It can be understood that, in other embodiments of the present invention, other methods may be used to obtain the final coupling relationship curve, for example, the second coupling relationship curve may be directly used as the final coupling relationship curve. Or it can be obtained directly through simulation through multiple experiments, or it can be obtained through other existing methods.

In summary, the present invention uses two kinds of kinematics simulation software CATIA and ADAMS software in combination, considers the performance of the elastic elements such as rubber bushing in the setting-up of suspension dynamic model and simulation, considers due to elasticity in motion simulation test The influence of component stress deformation and special working conditions on wheel motion. Therefore, compared with the commonly used rigid body model simulation, the wheel motion envelope obtained in the embodiment of the present invention can reflect a more accurate wheel motion trajectory. In addition, by using the CATIA/DMU module, the present invention proposes a convenient, quick and accurate method for making the tire motion envelope surface, and the obtained motion envelope surface is smooth and complete.

The wheel motion envelope obtained by the embodiment of the present invention is used to check the clearance between the wheel and the surrounding parts. The results comprehensively consider factors such as the elastic deformation of the car under complex working conditions, the manufacturing and use errors of the tire, and the obtained results It is closer to the actual situation and has high reliability and safety.

In addition, in the embodiment of the present invention, the movement of the wheel is only determined by the coordinate track of the center of the wheel and a point on the central axis. Compared with the prior art, the motion of the wheel no longer depends on the motion of the suspension and the steering mechanism. Therefore, applying this technical scheme to make the wheel envelope surface only needs to establish a kinematic model of the wheel, which can be applied to all models, and does not need to input the suspension geometric topology and hard point information of the model, which greatly improves the work efficiency.

It can be understood that those skilled in the art can understand that all or part of the processes in the methods of the above embodiments can be implemented through computer programs to instruct related hardware, and the programs can be stored in a computer-readable memory In the medium, when the program is executed, it may include the processes of the embodiments of the above-mentioned methods. Wherein, the storage medium may be a magnetic disk, an optical disk, a read-only memory (Read-Only Memory, ROM) or a random access memory (Random Access Memory, RAM), etc.

The above disclosure is only a preferred embodiment of the present invention, which certainly cannot limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope of the present invention.

Claims (10)

1. a method for making the front steering wheel envelope surface of an automobile, is characterized in that, comprises the steps: According to the wheel jump and steering final coupling relationship curve of the front steering wheel of the automobile, the tire envelope surface simulation analysis is carried out by the first dynamic simulation software, and the motion track file of the front steering wheel is generated; Make a static model of the tire profile according to the selected wheel tire model; According to the static model of the wheel and tire profile made, in the second kinematics simulation software, a motion simulation model containing only the wheel profile is established, and a fixed coordinate system is established according to the design requirements of the whole vehicle, and the origin and coordinates of the coordinate system are The axis direction is the same as that of the whole vehicle; Create appropriate kinematic pairs and drives on the wheel, so that the pose of the wheel is completely determined by the coordinates of the center point of the wheel and the fixed point on the central axis, and edit the law of motion curve to make the corresponding coordinates on the tire contour of the wheel according to the specified The trajectory curve in the motion trajectory file of the front steering wheel changes, so that the wheel performs a simulated motion, and the motion space of the wheel is swept by an envelope body to obtain the motion envelope surface of the wheel. 2. The method for making the envelope surface of the front steering wheel of an automobile as claimed in claim 1, wherein the final coupling relationship curve includes a plurality of coordinate points, and each coordinate point includes a wheel jump travel parameter and a steering gear The stroke parameters. 3. The method for making the envelope surface of the front steering wheel of an automobile as claimed in claim 2, wherein the motion track file of the front steering wheel at least includes: at each moment in the simulation experiment process, the front steering wheel The trajectory of the x, y, z coordinates of the center point of the wheel, and the trajectory of the x, y, z coordinates of a point on the central axis of the wheel that is a fixed distance from the wheel center. 4. the method for making the envelope surface of the front steering wheel of the automobile as claimed in claim 3, is characterized in that, the described formulating wheel tire model according to the selection, the step of making the static model of tire profile further comprises: Making a static model of the tire profile of the tire under normal working conditions, braking working conditions and accelerating working conditions. 5. the method for making the front steering wheel envelope surface of the automobile as claimed in claim 4, is characterized in that, the static model of the tire profile of described tire under normal operating conditions is specifically: According to the ETRTO standard, the cross-sectional shape diagram of a certain type of tire is obtained, and the cross-sectional shape of the tire is rotated around the center line to obtain the static model of the tire profile. 6. the method for making automobile front steering wheel envelope surface as claimed in claim 4, is characterized in that, the static model of the tire profile of described making described tire under braking working condition is specifically: According to the ETRTO standard, obtain the cross-sectional shape diagram of a certain type of tire; Taking the centerline of the wheel as the axis, rotating the cross-sectional shape of the tire by 180° from the positive direction of the Y-axis to the negative direction of the Y-axis to form the first part of the final size of the tire model; Translate the centerline of the wheel along the positive direction of the X coordinate by a radial deformation amount to form the axis P, and use P as the axis to rotate the tire section from the positive direction of the Y axis to the negative direction of the Y axis by 180° to form the second part of the final size of the tire model; Translate the tire section from the centerline to P to form the third part of the final size of the tire model; Combining the three parts to obtain a static model of the tire profile under the braking conditions. 7. The method for making the envelope surface of the front steering wheel of the automobile as claimed in claim 4, wherein the static model of the tire profile of the described tire under accelerated working conditions is specifically: According to the ETRTO standard, obtain the cross-sectional shape diagram of a certain type of tire; Taking the centerline of the wheel as the axis, rotating the cross-sectional shape of the tire by 180° from the positive direction of the Y-axis to the negative direction of the Y-axis to form the first part of the final size of the tire model; Translate the centerline of the wheel along the negative direction of the X-axis by a radial deformation amount to form the axis P, and use P as the axis to rotate the tire section from the positive direction of the Y-axis to the negative direction of the Y-axis by 180° to form the second part of the final size of the tire model; Translate the tire section from the centerline to P to form the third part of the final size of the tire model; Combining the three parts to obtain a static model of the tire profile under the braking conditions. 8. The method for making the envelope surface of the front steering wheel of an automobile as claimed in any one of claims 3-7, wherein the corresponding coordinate values on the tire profile of the wheel are made according to the movement of the front steering wheel The steps to change the trajectory curve in the trajectory file are as follows: At least make the x, y, z coordinate values of the center point of the static model of the wheel profile and the x, z coordinate values of a point on the central axis with a fixed distance from the center point according to the motion track file of the front steering wheel The corresponding trajectory movement in . 9. the method for making automobile front steering wheel envelope surface as claimed in claim 8, is characterized in that, further comprises: According to the manufactured tire enveloping surface of the front steering wheel of the automobile, the interference relationship between it and the surrounding parts of the tire is simulated. 10. the method for making automobile front steering wheel envelope as claimed in claim 8, is characterized in that, described first kinematics simulation software is ADAMS/Car software; Described second kinematics simulation software is CATIA/DMU software.