Analytic geometry-based steering pull rod mechanism design method and steering pull rod mechanism

Abstract

The invention belongs to the technical field of steering pull rod design, and particularly relates to a steering pull rod mechanism design method based on analytic geometry and a steering pull rod mechanism. The steering pull rod mechanism is simplified into a plane connecting rod mechanism, and four key hinge points are marked; establishing a coordinate system by taking P1 as an original point; the length, the initial angle and the P4 coordinate of the front steering swing arm are obtained; calculating two coordinates of a P2 point when the front steering swing arm rotates to a limit position; generating P2 ''and P2'' ''points by rotating P2 'P4 and P2'' P4 line segments; and connecting the line segments and constructing perpendicular bisectors, and determining the position of a P3 point by solving the intersection point of the perpendicular bisectors. According to the method, the steering pull rod mechanism is designed through analytic geometry and coordinate transformation, the accuracy of hinge point positioning is improved, and structural deviation caused by empirical estimation is reduced; the design complexity is reduced through standardization steps, the development period is shortened, the motion coordination of the steering system is optimized, and the method is suitable for the field of automobile chassis and the like needing high-precision motion control.

Description

Technical Field

[0001] This invention belongs to the field of steering tie rod design technology, specifically relating to a steering tie rod mechanism design method and steering tie rod mechanism based on analytical geometry. Background Technology

[0002] The steering tie rod mechanism is a key component of the vehicle steering system. Its main function is to transmit the steering commands input by the driver through the steering wheel to the wheels, thereby turning the wheels and completing the vehicle's steering action. Traditional steering tie rod mechanisms are often designed using empirical analogy or trial-and-error methods, requiring extensive physical prototype testing and repeated adjustments. This not only results in a long development cycle but also makes it difficult to ensure that the left and right wheels meet the Ackermann geometry during steering, which can easily lead to problems such as abnormal tire wear, sluggish steering response, or decreased handling stability.

[0003] When analyzing the spatial mechanism of steering tie rods, related technologies need to handle multiple rotational degrees of freedom, resulting in high computational complexity and susceptibility to interference from non-core motion parameters, leading to deviations in the calculation of key points. The synchronization of the front and rear steering arms lacks quantitative design basis; related technologies approximate matching through mechanical transmission ratios, failing to accurately guarantee the fit between tie rod length and arm rotation angle during steering. This leads to a mismatch in steering angles between the front and rear wheels, affecting steering accuracy and subjecting the tie rod to additional bending or tensile stress, thus shortening the mechanism's lifespan. Summary of the Invention

[0004] The analytical geometry-based design method for steering tie rod mechanisms provided by this invention transforms the design of complex steering tie rod mechanisms into a computable geometric problem, and uses analytical geometry methods to accurately solve for the position of the key point P3, thereby improving design accuracy and efficiency.

[0005] The methods include: S1: Simplify the steering tie rod mechanism into a planar linkage mechanism; S2: Mark four hinge points in the planar linkage mechanism, namely the hinge point P1 between the front swing arm support and the front steering swing arm, the hinge point P2 between the front steering swing arm and the steering tie rod, the hinge point P3 between the steering tie rod and the rear steering swing arm, and the hinge point P4 between the rear steering swing arm and the rear swing arm support, where P3 is the point to be determined. S3: Establish a Cartesian coordinate system with point P1 as the origin; S4: Obtain the length and initial angle of the front steering arm, and obtain the coordinates of point P4; S5: Obtain the front and rear steering angles of the front steering arm, and obtain the front and rear steering angles of the rear steering arm; S6: Based on the established coordinate system and the parameters obtained in S4, determine the coordinates of point P2; S7: Based on the obtained front and rear steering angles of the front steering arm, determine the two position coordinates of point P2 when the front steering arm rotates to the front and rear limit positions, respectively denoted as P2' and P2''. S8: Calculate the distance between point P2' and point P4, and calculate the distance between point P2'' and point P4; S9: Rotate line segment P2'P4 around point P4 in a first direction to obtain point P2'''; rotate line segment P2''P4 around point P4 in a second direction to obtain point P2''''; S10: Connect point P2' and point P2''' to form the first line segment, and connect point P2'' and point P2'''' to form the second line segment; S11: Confirm Point and The coordinates of the point; S12: Determine the midpoint and slope of the first line segment, and determine the midpoint and slope of the second line segment; S13: Construct the perpendicular bisectors of the first and second line segments respectively; S14: Calculate the intersection of the two perpendicular bisectors. The intersection is the location of point P3.

[0006] It should be further explained that S5 specifically includes the following steps: S51: Based on the vehicle's steering performance requirements, determine the maximum clockwise rotation angle and the maximum counterclockwise rotation angle of the front steering arm relative to its initial installation position, and record them as the front steering angle. and back corner ; S52: Based on forward steering angle The counterclockwise rotation angle of the rear steering arm under steering conditions is determined and recorded as the forward steering angle of the rear steering arm. ; S53: Based on back angle The required clockwise rotation angle of the rear steering arm under steering conditions is determined and recorded as the rear steering angle of the rear steering arm. .

[0007] It should be further explained that S6 specifically includes the following steps: S61: Based on the Cartesian coordinate system established in step S3, lock the hinge point P1 between the front swing arm support and the front steering arm as the origin of the coordinate system, and determine the coordinates of P1 as (0,0), which will serve as the reference for calculating the coordinates of the key points. S62: Extract the length L and initial angle of the front steering arm from the design parameters obtained in step S4. Two types of parameters were determined as input parameters for calculating the coordinates of hinge point P2; S63: Extract the front steering arm length L and initial angle. Substitute the coordinates into the calculation formula, and then... , The coordinates (x2, y2) of the hinge point P2 between the front steering arm and the steering tie rod are calculated, i.e. .

[0008] It should be further explained that S7 specifically includes the following steps: S71: Lock the rotation reference of the front steering arm, and with the hinge point P1 marked in step S2 as the rotation center, retrieve the front steering arm front angle obtained in step S5. Back corner The length L of the front steering arm and the initial angle obtained in step S4; S72: Drives the front steering arm to rotate clockwise around P1. The length L of the front steering arm after rotation and the combined angle Substitute the coordinates into the calculation formula, and then... , The corresponding position of P2 in the rotational state is calculated and denoted as... ; S73: Drive the front steering arm to rotate counterclockwise around P1. The length L of the front steering arm after rotation and the combined angle Substitute the coordinates into the calculation formula, and then... , The corresponding position of P2 in the rotational state is calculated and denoted as... .

[0009] It should be further explained that S8 specifically includes the following steps: S81: Retrieve coordinate parameters from the previous step to determine the data required for calculation: Extract , ,as well as Confirm that all coordinate parameters are based on the same Cartesian coordinate system established in step S3; S82: Based on P2' coordinates and P4 coordinates The straight-line distance between P2' and P4 can be calculated using formula (1). ; Formula (1) S83: Based on P2'' coordinates The straight-line distance between P2'' and P4 is calculated using the coordinate formula (2) for P4. ; Formula (2).

[0010] It should be further explained that S10 specifically includes the following steps: S101: Extract P2' coordinates P2''' coordinates P2'''' coordinates P2'' coordinates Confirm that all coordinates are in the same Cartesian coordinate system; S102: Connect P2' and P2''' to form the first line segment, and connect P2'' and P2'''' to form the second line segment, thus completing the geometric connection between the two target line segments; S103: Substitute the geometric parameters corresponding to the first and second line segments into formula (3) to calculate the length of the first line segment P2'P2''. The length of the second line segment P2' is calculated using formula (4). ; Formula (3) Formula (4).

[0011] It should be further explained that S11 specifically includes the following steps: S111: Targeting Solve for the coordinates of the point and establish a system of two quadratic equations in two variables: The distance to P4 is equal to , The distance to P2' is equal to As constraints, construct the system of equations shown in formula (5), and solve the system of equations to obtain the results. ; Formula (5) S112: Targeting Solve for the coordinates of the point and establish a system of two quadratic equations in two variables; The distance to P4 is equal to , The distance to P2'' is equal to As constraints, construct the system of equations shown in formula (6), and solve the system of equations to obtain the results. ; , formula (6).

[0012] It should be further explained that S12 specifically includes the following steps: S121: Based on , , , Ensure that all coordinates are in the same Cartesian coordinate system. S122: For the first line segment Calculate the slope and midpoint of the first line segment; Will and Substituting the coordinates into the slope formula and the midpoint coordinate formula, the slope of the first line segment can be obtained by solving formula (7). k Coordinates of point 1 and midpoint M ; Formula (7) S123: For the second line segment (P2''P2''''), calculate its slope and midpoint; and Substituting the coordinates into the slope formula and the midpoint coordinate formula, the slope of the second line segment can be obtained by solving formula (8). k 2 and the coordinates of the midpoint N ; Formula (8).

[0013] It should be further explained that S13 specifically includes the following steps: S131: Based on the slope relationship of perpendicular lines, the slope of the first line segment is... k 1 Substitute Solving for its corresponding perpendicular bisector yields the solution. l The slope of line segment 1; the slope of the second line segment. k 2 Substitute Solving for its corresponding perpendicular bisector yields the solution. l The slope of 2; S132: Extracted midpoint The perpendicular bisector is obtained by combining the points through which the line passes. l 1. Slope, substituting into the point-slope form equation, yields formula (11). l 1. Equation of the straight line; with the midpoint The point through which the line passes, combined with the perpendicular bisector. l 2. Slope, substituting into the point-slope form equation, yields formula (12). l 2. Equations of the straight lines; Formula (11) Formula (12).

[0014] According to another embodiment of this application, a steering tie rod mechanism is provided, the steering tie rod mechanism including: a front swing arm support, a front steering swing arm, a steering tie rod, a rear steering swing arm, and a rear swing arm support; The front steering arm and the front steering arm support, as well as the rear steering arm and the rear steering arm support, are connected by pins. The steering tie rods are hinged to the front and rear steering arms, respectively. Mark the hinge point between the front control arm support and the front steering control arm as P1, the hinge point between the front steering control arm and the steering tie rod as P2, the hinge point between the steering tie rod and the rear steering control arm as P3, and the hinge point between the rear steering control arm and the rear control arm support as P4.

[0015] As can be seen from the above technical solutions, the present invention has the following advantages: The analytical geometry-based steering tie rod mechanism design method provided by this invention adopts a planar linkage mechanism simplification strategy, eliminating the minimal spatial rotational degrees of freedom in the steering tie rod mechanism. The front and rear swing arm supports are simplified to fixed hinge supports, and the front and rear steering arms and steering tie rods are simplified to planar links, retaining only the core planar rotational degrees of freedom. A planar rectangular coordinate system is established, converting the positions of all hinge points into quantifiable coordinate data. Analytical geometric tools such as trigonometric functions, distances between two points, and perpendicular bisector equations are used to transform the mechanism's motion relationships into algebraic operations, achieving accurate solutions for the positions of key points. Based on the full-stroke rotation angle parameters of the front and rear steering arms, the front and rear rotation angles of the front and rear steering arms are determined, and the corresponding points (P2', P2'') of P2 at the extreme steering positions are calculated. Then, the extreme motion positions of the front and rear swing arms are associated by rotating a line segment around a fixed point. By connecting line segments and constructing a perpendicular bisector, the motion matching relationship between the front and rear control arms is transformed into solving for the intersection of the perpendicular bisectors. The geometric property that any point on the perpendicular bisector is equidistant from both ends of the line segment ensures a fixed tie rod length during steering, achieving synchronous adaptation of the front and rear control arm movements. A fully parametric design process is adopted, using the front steering arm length, initial angle, and P4 point coordinates as input parameters. A fixed algebraic operation logic outputs the P3 point position, forming a reusable design framework.

[0016] This invention replaces empirical estimation with coordinate quantization and algebraic solving, significantly improving the accuracy of the P3 point position calculation. This improves the consistency of mechanism motion during mass production, effectively reducing problems such as uneven steering feel and abnormal wear of tie rods. The introduction of full-stroke angle parameters and limit position calculations ensure that the design covers complete steering conditions, improving the reliability and passability of vehicle steering. The simultaneous solution of the perpendicular bisectors establishes a quantitative matching relationship for the front and rear swing arm movements, ensuring synchronous steering of the front and rear wheels during steering, reducing additional stress on the tie rods, and extending the service life of the mechanism. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the steering tie rod mechanism; Figure 2 A simplified schematic diagram of the steering tie rod mechanism; Figure 3 A schematic diagram of the marked key points; Figure 4 A schematic diagram of the established coordinate system. Detailed Implementation

[0019] The analytical geometry-based design method for steering tie rod mechanisms provided by this invention simplifies spatial steering tie rod mechanisms into planar linkage mechanisms, marking key hinge points and establishing a Cartesian coordinate system. By obtaining the initial angles, swing angle ranges, and installation position parameters of the front and rear steering arms, a corresponding set of equations is established based on geometric relationships. Utilizing the positional relationship of the arms before and after rotation and the rotation operation, the equation of the perpendicular bisector is constructed and its intersection point is determined, thereby determining the position of the hinge point between the steering tie rod and the rear steering arm. This invention replaces the traditional graphical method with analytical calculation, offering advantages such as accurate solutions, high efficiency, and ease of parametric design and optimization, effectively improving the design accuracy and efficiency of steering tie rod mechanisms.

[0020] The following describes in detail the analytical geometry-based steering tie rod mechanism design method of this application. Specific details, such as particular system structures and techniques, are presented for illustrative purposes rather than limiting, to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application can also be implemented in other embodiments without these specific details.

[0021] It should be understood that, when used in this specification, the term "comprising" indicates the presence of the described feature, integral, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof. The terms "comprising," "including," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0022] The terms "one embodiment" or "some embodiments" used in this application mean that one or more embodiments of this application include the specific features, structures, or characteristics described in that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this application do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized.

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Please see Figures 1 to 4 The diagram shown is a structural schematic of a steering tie rod mechanism in a specific embodiment. The steering tie rod mechanism mainly includes: a front control arm support 1, a front steering control arm 2, a steering tie rod 3, a rear steering control arm 4, and a rear control arm support 5.

[0025] The front steering arm 2 is connected to the front steering arm support 1, the rear steering arm 4 and the rear steering arm support 5 by a pin, and there is one degree of rotational freedom in one direction between them. The front steering arm support 1 and the rear steering arm support 5 can be simplified as fixed hinge supports, and the front steering arm 2 and the rear steering arm 4 can be simplified as connecting rods, and connected to the fixed hinge supports by hinges.

[0026] The steering tie rod 3 is connected to the front steering control arm 2 and the rear steering control arm 4 via ball joints, and has three rotational degrees of freedom in space. When designing the steering tie rod mechanism, considering only its rotational degree of freedom in one plane, the steering tie rod 3 can be simplified into a link, connected to the front steering control arm 2 and the rear steering control arm 4 via hinges. The simplified planar link mechanism is as follows: Figure 2 As shown.

[0027] For ease of subsequent calculations, the hinge point between the front control arm support 1 and the front steering arm 2 is marked as... P 1. Mark the hinge point between the front steering arm 2 and the steering tie rod 3 as... P 2. Mark the hinge point between the steering tie rod 3 and the rear steering control arm 4 as... P 3. Mark the hinge point of the rear steering arm 4 and the rear steering arm support 5 as... P 4, such as Figure 3 As shown. Solving for the steering tie rod mechanism involves solving... P The position of 3.

[0028] The steering tie rod mechanism design method in this embodiment includes the following steps: S1: Simplify the steering tie rod mechanism into a planar linkage mechanism.

[0029] In some embodiments, the steering tie rod mechanism includes: a front control arm support 1, a front steering control arm 2, a steering tie rod 3, a rear steering control arm 4, and a rear control arm support 5. The front steering control arm and its support, and the rear steering control arm and its support, each have one degree of rotational freedom in one direction. The steering tie rod is connected to the front and rear steering control arms via ball joints, and has three degrees of rotational freedom in space.

[0030] Considering that when the steering mechanism is working, the motion is concentrated in the same plane perpendicular to the vehicle's direction of travel, and the motion amplitude in other directions is extremely small and has a negligible impact on steering performance, the front and rear swing arm supports are simplified to fixed hinge supports, and the front and rear steering swing arms and steering tie rods are simplified to connecting rods. All connections are equivalent to hinge connections in the plane, ultimately forming a planar linkage mechanism with only planar rotational degrees of freedom.

[0031] S2: Mark four hinge points in the planar linkage mechanism, namely the hinge point P1 between the front swing arm support 1 and the front steering swing arm 2, the hinge point P2 between the front steering swing arm 2 and the steering tie rod 3, the hinge point P3 between the steering tie rod 3 and the rear steering swing arm 4, and the hinge point P4 between the rear steering swing arm 4 and the rear swing arm support 5, where P3 is the point to be determined.

[0032] In some embodiments, the marking process needs to accurately correspond to the main hinge positions of the simplified planar linkage mechanism: P1 is the fixed rotation center of the front steering arm, and its position is determined by the installation position of the front steering arm support. P2 is the force transmission node between the steering tie rod and the front steering arm, and it moves with the rotation of the front steering arm; P4 is the fixed rotation center of the rear steering arm, and its position is determined by the installation position of the rear steering arm support. P3 is the force transmission node between the steering tie rod and the rear steering arm. Its position directly determines the length and installation angle of the steering tie rod, which in turn affects the motion coordination of the entire steering mechanism. Therefore, it has become the main target of the design method.

[0033] Thus, the main design objective is determined to be solving P3, and all design steps revolve around the positional relationships of key points, establishing a unified geometric analysis benchmark to ensure that the analysis objects of each step are consistent.

[0034] S3: Establish a Cartesian coordinate system with point P1 as the origin.

[0035] In some embodiments, the axis directions of the coordinate system need to be determined in conjunction with the actual driving posture of the vehicle: the positive x-axis is set horizontally forward, consistent with the vehicle's driving direction. The positive y-axis is set vertically downward, perpendicular to the ground. The main reason for choosing P1 as the origin is that P1 is a fixed hinge support, and its position remains unchanged, thus the coordinate system established based on it has strong stability.

[0036] P1 serves as the rotation center of the front steering arm, with its coordinates fixed at (0,0), which simplifies the coordinate calculation of subsequent associated points of the front steering arm.

[0037] S4: Obtain the length and initial angle of the front steering arm 2, and obtain the coordinates of point P4.

[0038] In some embodiments, the length of the front steering arm specifically refers to the straight-line distance between P1 and P2, a parameter determined by the structural design dimensions of the front steering arm. The initial angle refers to the angle between the front steering arm and the vertically downward direction of the y-axis of the coordinate system when the vehicle is traveling in a straight line, and is determined by the initial installation posture of the vehicle steering system.

[0039] The coordinates of point P4 need to be obtained based on the coordinate system established by S3. The specific values ​​are determined by the installation position of the rear swing arm support and the overall chassis layout parameters. During the acquisition process, it is necessary to ensure that the coordinate data matches the coordinate system reference.

[0040] S5: Obtain the front and rear steering angles of the front steering arm 2, and obtain the front and rear steering angles of the rear steering arm 4.

[0041] In some embodiments, based on the synchronization requirements of steering motion, the rotation angle range of the front and rear steering arms under extreme steering conditions is determined, providing angle parameters for simulating extreme steering positions and calculating the extreme positions of key points.

[0042] S5 specifically includes the following steps: S51: Based on the vehicle steering performance requirements adapted to the steering tie rod mechanism, determine the steering limit travel of the front steering arm; taking the hinge point P1 between the steering arm and the front steering arm support as the center of rotation, and combining the length L of the front steering arm, convert the arc length corresponding to the limit travel of the front steering arm's forward rotation into its initial angle. The clockwise deflection angle is recorded as the forward steering angle of the front steering arm. ; Convert the arc length corresponding to the limit travel of the rearward rotation of the front steering control arm into its initial angle. The counterclockwise deflection angle is recorded as the rear steering angle of the front steering arm. .

[0043] In some embodiments, the maximum travel of the front steering arm is determined from the overall vehicle steering performance requirements. Then, with the hinge point P1 as the center, the travel is converted into the rotation angle of the front steering arm using the correspondence between the central angle and the arc length in circular motion, thereby obtaining the front steering angle. and back corner .

[0044] S52: For the forward steering angle of the front steering arm For the corresponding steering conditions, determine the steering action that the rear steering arm needs to complete. Using the hinge point P4 between the rear steering arm and the rear control arm support as the center of rotation, and combining the design dimensions of the rear steering arm, convert the arc length corresponding to the steering action into a counterclockwise deflection angle relative to the initial position of the rear steering arm. Record this angle as the forward steering angle of the rear steering arm. .

[0045] In some embodiments, based on the forward turning condition of the front steering arm and in accordance with the synchronization requirements of the steering action, the rotation direction and angle of the rear steering arm are determined to ensure that the front and rear steering arms are linked through the steering tie rod. This ensures that the movement of the rear steering arm corresponds to the forward turning condition of the front steering arm, avoiding tie rod jamming or transmission failure during steering.

[0046] S53: Rear steering angle for the front steering arm For the corresponding steering conditions, determine the steering action that the rear steering arm needs to complete. Using the hinge point P4 between the rear steering arm and the rear control arm support as the center of rotation, convert the arc length corresponding to the steering action into a clockwise deflection angle relative to the initial position of the rear steering arm. Record this angle as the rear steering angle of the rear steering arm. .

[0047] Based on the rearward steering condition of the front steering arm, the corresponding rotation direction and angle of the rear steering arm are determined to ensure that the front and rear steering arms can still be linked through the steering tie rod when steering in opposite directions. This covers the two-way steering conditions of the steering system, allowing the designed steering tie rod mechanism to adapt to complete steering actions.

[0048] S6: Based on the established coordinate system and the parameters obtained in S4, determine the coordinates of point P2.

[0049] In some embodiments, the coordinate decomposition logic of trigonometric functions is used to convert the length and initial angle of the front steering arm into specific coordinate data of P2, thereby realizing the conversion of the component's geometric features into algebraic values ​​and providing an initial reference point for calculating the motion position.

[0050] S6 specifically includes the following steps: S61: Based on the Cartesian coordinate system established in step S3, lock the hinge point P1 between the front swing arm support and the front steering arm as the origin of the coordinate system, and determine the coordinates of P1 as (0,0), which will serve as the reference for calculating the coordinates of the key points.

[0051] S62: Extract the length L and initial angle of the front steering arm from the design parameters obtained in step S4. Two types of parameters are determined as input parameters for calculating the coordinates of hinge point P2.

[0052] In step S4 of this embodiment, the length L and initial angle of the front steering arm have been obtained. Where the length L of the front steering arm refers to the straight-line distance between hinge points P1 and P2, and the initial angle... This refers to the angle between the front steering arm and the y-axis of the coordinate system when the front steering arm is initially stationary. This step extracts these two parameters to ensure that the parameter values ​​are consistent with the design parameters obtained in step S4.

[0053] S63: Extract the front steering arm length L and initial angle. Substitute the coordinates into the calculation formula, and then... , The coordinates (x2, y2) of the hinge point P2 between the front steering arm and the steering tie rod are calculated, i.e. .

[0054] This embodiment, based on the coordinate decomposition rules of a Cartesian coordinate system, considers the front steering arm in its initial state as a line segment pointing from P1(0,0) to P2. This line segment is then decomposed along the x-axis and y-axis of the coordinate system. Since... It is the angle between the front steering arm and the y-axis. According to trigonometric relationships, the coordinate components of P2 in the x-axis direction are: The coordinate components in the y-axis direction are . L and Substituting the above two equations, the specific coordinates of P2 can be directly calculated. This coordinate accurately reflects the position of P2 in the entire planar linkage mechanism in the initial state.

[0055] S7: Based on the obtained front and rear turning angles of the front steering arm (2), determine the two position coordinates corresponding to point P2 when the front steering arm (2) rotates to the front and rear limit positions, respectively denoted as P2' and P2''.

[0056] In some embodiments, based on the invariant length characteristic of circular motion, combined with angle superposition logic, the coordinates of P2 under the limit rotation angle are calculated using trigonometric functions to simulate the motion position of the front steering arm under extreme conditions.

[0057] S7 specifically includes the following steps: S71: Lock the rotation reference of the front steering arm, and with the hinge point P1 marked in step S2 as the rotation center, retrieve the front steering arm front angle obtained in step S5. Back corner And the front steering arm length L and initial angle obtained in step S4 The above parameters are the main basis for calculating the position of P2 after rotation.

[0058] S72: Drives the front steering arm to rotate clockwise around P1. The length L of the front steering arm after rotation and the combined angle Substitute the coordinates into the calculation formula, and then... , The corresponding position of P2 in this rotational state is calculated and denoted as . .

[0059] S73: Drive the front steering arm to rotate counterclockwise around P1. The length L of the front steering arm after rotation and the combined angle Substitute the coordinates into the calculation formula, and then... , The corresponding position of P2 in this rotational state is calculated and denoted as . .

[0060] In some embodiments, based on the geometric characteristics of circular arc motion, the trajectory of P2 when the front steering arm rotates is a circular arc with a fixed radius. Trigonometric functions are used to convert the rotation angle and component length into planar coordinates, which quantifies the mechanical rotational motion of the component into calculable coordinate data.

[0061] This embodiment covers the two extreme steering conditions of the front steering arm, and the obtained P2'' coordinates are complementary to the P2' coordinates of S72, providing data for the mechanism design under the bidirectional steering condition in the method, and avoiding insufficient adaptability of the steering tie rod mechanism due to the lack of data on the latter extreme condition.

[0062] S8: Calculate the distance between point P2' and point P4, and calculate the distance between point P2'' and point P4.

[0063] In some embodiments, the coordinates of two key points are transformed into measurable distance parameters using an algebraic formula for the distance between two points in a Cartesian coordinate system, providing basic data for analyzing line segment rotation and length constraints.

[0064] S8 specifically includes the following steps: S81: Retrieve coordinate parameters from the previous step to determine the data required for calculation: Extract , ,as well as Confirm that all coordinate parameters are based on the same Cartesian coordinate system established in step S3.

[0065] S82: Based on P2' coordinates and P4 coordinates The straight-line distance between P2' and P4 can be calculated using formula (1). ; Formula (1).

[0066] In some embodiments, it has been confirmed that the coordinates of P2' and P4 are both within the coordinate system established in step S3, satisfying the application conditions of the distance formula between two points. The main function of the distance formula between two points is to quantify the straight-line distance between two points by taking the square root of the sum of the squares of the coordinate differences. Formula (1) is constructed based on this logic. Substituting the x-coordinate x2' and y-coordinate y2' of P2' and the x-coordinate x4 and y-coordinate y4 of P4 into formula (1), the coordinate differences (x2'-x4) and (y2'-y4) are calculated, and then the square root of the sum of the squares of the differences is taken to obtain the straight-line distance between P2' and P4. This distance reflects the spatial span between P2' and P4 under the front limit steering condition.

[0067] S83: Based on P2'' coordinates The straight-line distance between P2'' and P4 is calculated using the coordinate formula (2) for P4. ; Formula (2).

[0068] In some embodiments, a geometric quantization method based on the distance formula between two points is used, changing only the input coordinate parameters to adapt to the distance calculation requirements of the rear extreme steering condition. This allows for the acquisition of key distance parameters under the rear extreme steering condition. , and obtained from S82 A two-way working condition distance dataset is generated to ensure that the line segment rotation operation under the later extreme working condition in step S9 has a corresponding length parameter.

[0069] S9: Connecting line segment , line segment by P 4 is the center of rotation, rotating counterclockwise. And note the key points. exist Rotate counterclockwise The position after is denoted as ; to line segment by P Rotate clockwise around the center of rotation. And note the key points. exist Rotate clockwise The position after is denoted as .

[0070] In some embodiments, based on the invariance of the length of the rigid body rotation and the synchronicity of the steering motion, the rotation state of the rear steering arm under extreme steering conditions is simulated by rotating a line segment around a fixed point, thereby obtaining the position of the rear steering arm associated point corresponding to the extreme position of the front steering arm.

[0071] S10: Connect points P2' and P2''' to form the first line segment, and connect points P2'' and P2'''' to form the second line segment.

[0072] In some embodiments, the basic rule of two points determining a straight line in plane geometry is used to connect corresponding key points under extreme working conditions to form a line segment, transforming the scattered point relationships into the overall geometric relationship of the line segment, and providing a specific geometric object for the construction of the perpendicular bisector.

[0073] S10 specifically includes the following steps: S101: Extract P2' coordinates P2''' coordinates P2'''' coordinates P2'' coordinates Confirm that all coordinates are in the same Cartesian coordinate system.

[0074] This embodiment mainly completes the preliminary data preparation for line segment construction and length calculation. All retrieved coordinate parameters are the main calculation results of the preliminary steps, and their sources and consistency are checked one by one. Among them, P2' is the P2 point corresponding to the extreme position of the front steering arm, and P2''' is the line segment P2'P4 rotated counterclockwise around P4. The point corresponding to P2' is P2'', which is the P2 point corresponding to the extreme position of the front steering arm's rearward rotation. P2'''' is the line segment P2''P4 rotated clockwise around P4. The point corresponding to P2'' after that.

[0075] S102: Connect P2' and P2''' to form the first line segment, and connect P2'' and P2'''' to form the second line segment, thus completing the geometric connection between the two target line segments.

[0076] S103: Substitute the geometric parameters corresponding to the first and second line segments into formula (3) to calculate the length of the first line segment P2'P2''. The length of the second line segment P2' is calculated using formula (4). ; Formula (3) Formula (4).

[0077] This embodiment utilizes the cosine theorem to calculate the length of the third side from two known sides and their included angle of a triangle using geometric quantification logic. The known side length obtained in step S8 is then used... , The rotation angle obtained in step S5 ( , The angle and the geometric features of the known length are converted into the length features of the target line segment. Here, the geometric features of the angle and the known length are quantified into the length features of the target line segment.

[0078] S11: Confirm Point and The coordinates of the point.

[0079] In some embodiments, the distance is transformed into a system of algebraic equations, and the coordinates of key points are uniquely determined using algebraic solution methods, thereby achieving precise quantification of geometric relationships and providing accurate coordinate data for line segment feature analysis.

[0080] S11 specifically includes the following steps: S111: Targeting Solve for the coordinates of the point and establish a system of two quadratic equations in two variables: The distance to P4 is equal to , The distance to P2' is equal to As constraints, construct the system of equations shown in formula (5), and solve the system of equations to obtain the results. .

[0081] Formula (5) S112: Targeting Solve for the coordinates of the point and establish a system of two quadratic equations in two variables: The distance to P4 is equal to , The distance to P2'' is equal to As constraints, construct the system of equations shown in formula (6), and solve the system of equations to obtain the results. ; , formula (6).

[0082] S12: Determine the midpoint and slope of the first line segment, and determine the midpoint and slope of the second line segment.

[0083] In some embodiments, the coordinate data of the endpoints of a line segment are converted into the center position and inclination of the line segment using the quantification formulas of the midpoint and slope in plane geometry, providing direct parameter support for the construction of the perpendicular bisector.

[0084] S12 specifically includes the following steps: S121: Based on , , , Confirm that all coordinates are in the same Cartesian coordinate system.

[0085] In some embodiments, the preliminary data preparation for calculating the slope and midpoint of the line segment involves verifying the source and consistency of all retrieved coordinates, which are the main calculation results of the preceding steps. Specifically, P2' is the coordinate of the hinge point corresponding to the forward turning limit position of the front steering arm. P2''' is the coordinate of the corresponding point after line segment P2'P4 rotates around P4. P2'' is the coordinate of the hinge point corresponding to the backward turning limit position of the front steering arm. P2'''' is the coordinate of the corresponding point after line segment P2''P4 rotates around P4. It is confirmed that all coordinates remain within the coordinate system reference established in step S3 to avoid deviations in slope and midpoint calculations due to reference misalignment, and the numerical integrity of the coordinate parameters is checked.

[0086] S122: For the first line segment Calculate the slope and midpoint of the first line segment; Will and Substituting the coordinates into the slope formula and the midpoint coordinate formula, the slope of the first line segment can be obtained by solving formula (7). k Coordinates of point 1 and midpoint M ; Formula (7) In this embodiment, the first line segment is the geometric carrier formed by connecting P2' and P2'''. The slope and midpoint are the main parameters for constructing the perpendicular bisector in the subsequent process. The slope formula quantifies the inclination of the line segment by the ratio of the difference between the ordinates and the abscissas of the two points. The midpoint coordinate formula determines the center position of the line segment by the average of the coordinates of the two points. Together, they constitute the main logic of formula (7).

[0087] The collection in step S121 and Substituting the coordinates into formula (7), first calculate the difference between the ordinates (y2'''-y2') and the difference between the abscissas (x2'''-x2'), and then obtain the slope by comparing the values. k 1. Take the average of the x and y coordinates of the two points to obtain the coordinates of the midpoint M, thus completing the quantification of the key feature parameters of the first line segment.

[0088] S123: For the second line segment (P2''P2''''), calculate its slope and midpoint: and Substituting the coordinates into the slope formula and the midpoint coordinate formula, the slope of the second line segment can be obtained by solving formula (8). k 2 and the coordinates of the midpoint N ; Formula (8).

[0089] In some embodiments, the second line segment is a geometrical carrier connecting P2'' and P2'''', with a slopek The coordinates of point 2 and midpoint N are obtained using formula (8). The aggregated... and Substitute the coordinates into formula (8), calculate the difference between the ordinate (y2''''-y2'') and the difference between the abscissa (x2''''-x2''), and obtain the slope by the ratio. k 2. Take the average of the x and y coordinates of the two points to obtain the coordinates of the midpoint N. Ensure that the construction of the perpendicular bisector can cover both extreme steering conditions to avoid insufficient completeness of the P3 solution due to missing parameters of a single condition, which would affect the design adaptability of the steering tie rod mechanism.

[0090] S13: Construct the perpendicular bisectors of the first and second line segments respectively.

[0091] In some embodiments, based on the geometric properties of the perpendicular bisector and the rules for constructing the equation of a straight line, the midpoint and slope of a line segment are transformed into a quantifiable equation of a straight line, realizing the algebraic expression of the geometric perpendicular bisector and providing algebraic operation objects for subsequent solving of the intersection point.

[0092] S13 specifically includes the following steps: S131: Based on the slope relationship of perpendicular lines, the slope of the first line segment is... k 1 Substitute Solving for its corresponding perpendicular bisector yields the solution. l The slope of line segment 1; the slope of the second line segment. k 2 Substitute Solving for its corresponding perpendicular bisector yields the solution. l The slope of 2.

[0093] S132: Extracted midpoint The perpendicular bisector is obtained by combining the points through which the line passes. l 1. Slope, substituting into the point-slope form equation, yields formula (11). l 1. Equation of the straight line; with the midpoint The point through which the line passes, combined with the perpendicular bisector. l 2. Slope, substituting into the point-slope form equation, yields formula (12). l 2. Equations of the straight lines; Formula (11) Formula (12).

[0094] In some embodiments, based on the geometric construction logic of the point-slope line equation, and constrained by the two main attributes of the perpendicular bisector passing through the midpoint of the original line segment and being perpendicular to the original line segment, the midpoint coordinates and the slope of the perpendicular bisector are transformed into specific line equations, realizing the algebraic quantification of the geometric characteristics of the perpendicular bisector. The quantification of the equation transforms the solution of P3 from geometric construction to precise algebraic operations, improving the reliability of the solution.

[0095] S14: Calculate the intersection of the two perpendicular bisectors. The intersection is the location of point P3.

[0096] In some embodiments, the solution process involves solving the equations of the two perpendicular bisectors obtained by S13 simultaneously, and then solving the system of equations using algebraic operations to find the unique solution. The coordinates corresponding to this solution are the coordinates of the intersection point of the two perpendicular bisectors.

[0097] The reason for choosing P3 as the intersection point is that any point on the perpendicular bisector is equidistant from the two endpoints of the line segment. Therefore, the intersection point is equidistant from P2' and P2''', and equidistant from P2'' and P2'''', which perfectly satisfies the constraint of fixed steering tie rod length, ensuring that P3 is the only connection point that meets the motion coordination requirements of the steering mechanism.

[0098] In this way, the hinge point P3 between the steering tie rod and the rear steering arm is obtained, which completes the main goal of the entire design method: to ensure that the designed P3 position enables the steering tie rod mechanism to move in a coordinated manner throughout the entire steering stroke, and to avoid problems such as tie rod length mismatch and movement jamming.

[0099] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0100] It should be understood that when an element or layer is referred to as being "connected" or "coupled" to another element or layer "on" it may be directly connected or coupled to said other element or layer, or there may be intermediate elements or layers. Conversely, when an element is referred to as being "directly connected" or "directly coupled" to another element or layer "on" it is not an intermediate element or layer. Similar figures in all figures indicate similar elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0101] Spatially relative terms such as “below,” “under,” “lower,” “above,” “above,” etc., may be used here to describe the relationship between one element or feature and another, as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation other than those shown in the figure. For example, if the device in the figure were flipped over, the element described as “below” or “under” other elements or features would be facing “above” other elements or features. Thus, the exemplary term “below” can include both above and below orientations. Other orientations (rotation 90 degrees or other orientations) may be adopted, and the spatially relative terms used herein will be interpreted accordingly.

[0102] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the expression herein. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that, when used in this specification, the term “comprising” means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0103] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A design method for a steering tie rod mechanism based on analytical geometry, characterized in that, The methods include: S1: Simplify the steering tie rod mechanism into a planar linkage mechanism; S2: Mark four hinge points in the planar linkage mechanism, namely the hinge point P1 between the front swing arm support (1) and the front steering swing arm (2), the hinge point P2 between the front steering swing arm (2) and the steering tie rod (3), the hinge point P3 between the steering tie rod (3) and the rear steering swing arm (4), and the hinge point P4 between the rear steering swing arm (4) and the rear swing arm support (5), where P3 is the point to be determined; S3: Establish a Cartesian coordinate system with point P1 as the origin; S4: Obtain the length and initial angle of the front steering arm (2), and obtain the coordinates of point P4; S5: Obtain the front and rear steering angles of the front steering arm (2) and the front and rear steering angles of the rear steering arm (4); S6: Based on the established coordinate system and the parameters obtained in S4, determine the coordinates of point P2; S7: Based on the obtained front and rear turning angles of the front steering arm (2), determine the two position coordinates of point P2 when the front steering arm (2) rotates to the front and rear limit positions, respectively denoted as P2' and P2''. S8: Calculate the distance between point P2' and point P4, and calculate the distance between point P2'' and point P4; S9: Rotate line segment P2'P4 around point P4 in a first direction to obtain point P2'''; rotate line segment P2''P4 around point P4 in a second direction to obtain point P2''''; S10: Connect point P2' and point P2''' to form the first line segment, and connect point P2'' and point P2'''' to form the second line segment; S11: Confirm Point and The coordinates of the point; S12: Determine the midpoint and slope of the first line segment, and determine the midpoint and slope of the second line segment; S13: Construct the perpendicular bisectors of the first and second line segments respectively; S14: Calculate the intersection of the two perpendicular bisectors. The intersection is the location of point P3.

2. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S5 specifically includes the following steps: S51: Based on the overall vehicle steering performance requirements, determine the maximum clockwise rotation angle and the maximum counterclockwise rotation angle of the front steering arm (2) relative to its initial installation position, and record them as the front steering angle. and back corner ; S52: Based on forward steering angle The counterclockwise rotation angle of the rear steering arm (4) under steering conditions is determined and recorded as the forward steering angle of the rear steering arm. ; S53: Based on back angle The clockwise rotation angle that the rear steering arm (4) needs to cooperate with under steering conditions is determined and recorded as the rear steering angle of the rear steering arm. .

3. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S6 specifically includes the following steps: S61: Based on the Cartesian coordinate system established in step S3, lock the hinge point P1 between the front swing arm support and the front steering arm as the origin of the coordinate system, and determine the coordinates of P1 as (0,0), which will serve as the reference for calculating the coordinates of the key points. S62: Extract the length L and initial angle of the front steering arm from the design parameters obtained in step S4. Two types of parameters were determined as input parameters for calculating the coordinates of hinge point P2; S63: Extract the front steering arm length L and initial angle. Substitute the coordinates into the calculation formula, and then... , The coordinates (x2, y2) of the hinge point P2 between the front steering arm and the steering tie rod are calculated, i.e. .

4. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S7 specifically includes the following steps: S71: Lock the rotation reference of the front steering arm, and with the hinge point P1 marked in step S2 as the rotation center, retrieve the front steering arm front angle obtained in step S5. Back corner The length L of the front steering arm and the initial angle obtained in step S4; S72: Drive the front steering arm to rotate clockwise around P1. The length L of the front steering arm after rotation and the combined angle Substitute the coordinates into the calculation formula, and then... , The position of P2 under the rotational state is calculated and denoted as... ; S73: Drive the front steering arm to rotate counterclockwise around P1. The length L of the front steering arm after rotation and the combined angle Substitute the coordinates into the calculation formula, and then... , The position of P2 under the rotational state is calculated and denoted as... .

5. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S8 specifically includes the following steps: S81: Retrieve coordinate parameters from the previous step to determine the data required for calculation: Extract , ,as well as Confirm that all coordinate parameters are based on the same Cartesian coordinate system established in step S3; S82: Based on P2' coordinates and P4 coordinates The straight-line distance between P2' and P4 can be calculated using formula (1). ; Official (1) S83: Based on P2'' coordinates The straight-line distance between P2'' and P4 is calculated using the coordinate formula (2) for P4. ; Official (2).

6. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S10 specifically includes the following steps: S101: Extract P2' coordinates P2''' coordinates P2'''' coordinates P2'' coordinates Confirm that all coordinates are in the same Cartesian coordinate system; S102: Connect P2' and P2''' to form the first line segment, and connect P2'' and P2'''' to form the second line segment, thus completing the geometric connection between the two target line segments; S103: Substitute the geometric parameters corresponding to the first and second line segments into formula (3) to calculate the length of the first line segment P2'P2''. The length of the second line segment P2' is calculated using formula (4). ; Official (3) Official (4).

7. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S11 specifically includes the following steps: S111: Targeting Solve for the coordinates of the point and establish a system of two quadratic equations in two variables: The distance to P4 is equal to , The distance to P2' is equal to As constraints, construct the system of equations shown in formula (5), and solve the system of equations to obtain the results. ; Official (5) S112: Targeting Solve for the coordinates of the point and establish a system of two quadratic equations in two variables; The distance to P4 is equal to , The distance to P2'' is equal to As constraints, construct the system of equations shown in formula (6), and solve the system of equations to obtain the results. ; , Official (6).

8. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S12 specifically includes the following steps: S121: Based on , , , Ensure that all coordinates are in the same Cartesian coordinate system. S122: For the first line segment Calculate the slope and midpoint of the first line segment; Will and Substituting the coordinates into the slope formula and the midpoint coordinate formula, the slope of the first line segment can be obtained by solving formula (7). k Coordinates of point 1 and midpoint M ; Official (7) S123: For the second line segment (P2''P2''''), calculate its slope and midpoint; and Substituting the coordinates into the slope formula and the midpoint coordinate formula, the slope of the second line segment can be obtained by solving formula (8). k 2 and the coordinates of the midpoint N ; Official (8).

9. The design method for a steering tie rod mechanism based on analytical geometry according to claim 1, characterized in that, S13 specifically includes the following steps: S131: Based on the slope relationship of perpendicular lines, the slope of the first line segment is... k 1 Substitute Solving for its corresponding perpendicular bisector yields the solution. l The slope of line segment 1; the slope of the second line segment. k 2 Substitute Solving for its corresponding perpendicular bisector yields the solution. l The slope of 2; S132: Extracted midpoint The perpendicular bisector is obtained by combining the points through which the line passes. l 1. Slope, substituting into the point-slope form equation, yields formula (11). l 1. Equation of the straight line; with the midpoint The point through which the line passes, combined with the perpendicular bisector. l 2. Slope, substituting into the point-slope form equation, yields formula (12). l 2. Equations of the straight lines; Official (11) Official (12).

10. A steering tie rod mechanism, characterized in that, The steering tie rod mechanism is designed based on the analytical geometry-based steering tie rod mechanism design method according to any one of claims 1 to 9; the steering tie rod mechanism includes: front swing arm support (1), front steering swing arm (2), steering tie rod (3), rear steering swing arm (4), and rear swing arm support (5). The front steering arm (2) and the front steering arm support (1) are connected by pins as are the rear steering arm (4) and the rear steering arm support (5). The steering tie rod (3) is hinged to the front steering arm (2) and the rear steering arm (4) respectively; The hinge point between the front swing arm support (1) and the front steering swing arm (2) is marked as P1, the hinge point between the front steering swing arm (2) and the steering tie rod (3) is marked as P2, the hinge point between the steering tie rod (3) and the rear steering swing arm (4) is marked as P3, and the hinge point between the rear steering swing arm (4) and the rear swing arm support (5) is marked as P4.

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