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CN-122020844-A - Design method of steering pull rod mechanism based on analytical geometry and steering pull rod mechanism

CN122020844ACN 122020844 ACN122020844 ACN 122020844ACN-122020844-A

Abstract

The invention belongs to the technical field of steering pull rod design, and particularly relates to a steering pull rod mechanism design method and a steering pull rod mechanism based on analytic geometry, wherein the steering pull rod mechanism is simplified into a planar connecting rod mechanism and four key hinge points are marked, a coordinate system is established by taking P 1 as an origin, the length, an initial angle and P 4 coordinates of a front steering swing arm are obtained, two coordinates of a P 2 point when the front steering swing arm rotates to a limit position are calculated, a P 2 '''、P 2 '' '' point is generated by rotating a P 2 'P 4 、P 2 ''P 4 line segment, a line segment is connected, a perpendicular-to-the-middle line is constructed, and the position of the P 3 point is determined by solving the intersection point of the perpendicular-to-middle line. The method realizes the design of the steering pull rod mechanism by analyzing geometric and coordinate transformation, improves the positioning accuracy of a hinge point, reduces structural deviation caused by experience estimation, reduces design complexity by a standardization step, shortens development period, optimizes the motion coordination of a steering system, and is suitable for the fields of automobile chassis and the like which need high-precision motion control.

Inventors

  • LI JUNXI

Assignees

  • 中国重汽集团泰安五岳专用汽车有限公司

Dates

Publication Date
20260512
Application Date
20251229

Claims (10)

  1. 1. The design method of the steering pull rod mechanism based on the analytical geometry is characterized by comprising the following steps of: s1, simplifying a steering pull rod mechanism into a plane connecting rod mechanism; S2, marking four hinge points in a plane connecting rod mechanism, namely a hinge point P 1 of a front swing arm support (1) and a front steering swing arm (2), a hinge point P 2 of the front steering swing arm (2) and a steering pull rod (3), a hinge point P 3 of the steering pull rod (3) and a rear steering swing arm (4) and a hinge point P 4 of the rear steering swing arm (4) and a rear swing arm support (5), wherein P 3 is a point to be solved; s3, establishing a plane rectangular coordinate system by taking the P 1 point as an origin; s4, acquiring the length and the initial angle of the front steering swing arm (2), and acquiring the coordinate of a point P 4 ; S5, acquiring a front corner and a rear corner of a front steering swing arm (2), and acquiring a front corner and a rear corner of a rear steering swing arm (4); s6, determining the coordinates of the point P 2 based on the established coordinate system and the parameters acquired in the S4; S7, determining two position coordinates corresponding to a point P 2 when the front steering swing arm (2) rotates to a front limit position and a rear limit position based on the acquired front rotation angle and rear rotation angle of the front steering swing arm (2), and respectively marking as P 2 ' and P 2 ' '; S8, calculating the distance between the P 2 'point and the P 4 point, and calculating the distance between the P 2 ' point and the P 4 point; S9, rotating the line segment P 2 'P 4 around the point P 4 in a first direction to obtain a point P 2 '' ', and rotating the line segment P 2 ''P 4 around the point P 4 in a second direction to obtain a point P 2 ' ''; S10, respectively connecting the P 2 ' point and the P 2 ' ' ' point to form a first line segment, and connecting the P 2 ' ' point and the P 2 ' ' ' point to form a second line segment; S11, determining Dots and dots Coordinates of the points; s12, determining the midpoint and the slope of the first line segment, and determining the midpoint and the slope of the second line segment; s13, respectively constructing a perpendicular bisector of the first line segment and the second line segment; and S14, calculating an intersection point of the two perpendicular bisectors, wherein the intersection point is the position of the P 3 point.
  2. 2. The analytical geometry-based steering linkage design method according to claim 1, wherein S5 specifically comprises the steps of: S51, determining the maximum clockwise rotation angle and the maximum anticlockwise rotation angle of the front steering swing arm (2) relative to the initial installation position based on the steering performance requirement of the whole vehicle, and recording the maximum clockwise rotation angle and the maximum anticlockwise rotation angle as the front rotation angles respectively And rear corner ; S52 based on the front rotation angle Determining the counter-clockwise rotation angle of the rear steering swing arm (4) under the steering working condition, and recording the counter-clockwise rotation angle as the front rotation angle of the rear steering swing arm ; S53 based on the rear rotation angle Determining the clockwise rotation angle of the rear steering swing arm (4) to be matched under the steering working condition, and recording the clockwise rotation angle as the rear rotation angle of the rear steering swing arm 。
  3. 3. The analytical geometry-based steering linkage design method according to claim 1, wherein S6 specifically comprises the steps of: S61, based on the plane rectangular coordinate system established in the step S3, locking a hinging point P 1 of the front swing arm support and the front steering swing arm as a coordinate system origin, determining the coordinate of P 1 as (0, 0), and taking the coordinate as a reference for calculating the key point coordinate; s62, extracting the length L and the initial angle of the front steering swing arm from the design parameters obtained in the step S4 Two types of parameters are determined as input parameters for calculating the coordinates of the hinge point P 2 ; s63, extracting the length L and the initial angle of the front steering swing arm Substituting into the coordinate calculation formula by 、 The coordinate (x 2 ,y 2 ) of the hinge point P 2 of the front steering swing arm and the steering pull rod is calculated 。
  4. 4. The analytical geometry-based steering linkage design method according to claim 1, wherein S7 specifically comprises the steps of: S71, locking a rotation reference of the front steering swing arm, taking the hinge point P 1 marked in the step S2 as a rotation center, and calling the front rotation angle of the front steering swing arm obtained in the step S5 Rear corner S4, obtaining the length L and the initial angle of the front steering swing arm; S72, driving the front steering swing arm to rotate around the P 1 in the clockwise direction The length L and the synthetic angle of the front steering swing arm after rotation Substituting into the coordinate calculation formula by 、 Calculating the corresponding position of P 2 in the rotating state, and marking as ; S73, driving the front steering swing arm to rotate around the P 1 in the anticlockwise direction The length L and the synthetic angle of the front steering swing arm after rotation Substituting into the coordinate calculation formula by 、 Calculating the corresponding position of P 2 in the rotating state, and marking as 。
  5. 5. The analytical geometry-based steering linkage design method according to claim 1, wherein S8 specifically comprises the steps of: S81, retrieving the coordinate parameters in the pre-step, determining the data required by calculation, extracting 、 A kind of electronic device Confirming that all coordinate parameters are based on the same plane rectangular coordinate system established in the step S3; S82 based on P 2 ' coordinates And P 4 coordinates The straight line distance between P 2 ' and P 4 is calculated by the formula (1) ; Formula (1) S83 based on P 2 ' coordinates Calculating the linear distance between P 2 ' and P 4 according to the coordinate formula (2) of P 4 ; Equation (2).
  6. 6. The analytical geometry-based steering linkage design method according to claim 1, wherein S10 specifically comprises the steps of: S101, extracting P 2 ' coordinates P 2 ' "coordinates P 2 '' '' coordinates P 2 '' coordinates Confirming that all coordinates are in a rectangular coordinate system of the same plane; S102, connecting P 2 ' with P 2 ' ' ' to form a first line segment, and connecting P 2 ' ' with P 2 ' ' ' to form a second line segment, so as to complete the geometric association construction of the two target line segments; S103, substituting the geometric parameters corresponding to the first line segment and the second line segment into the formula (3) respectively to calculate the length of the first line segment P 2 'P 2 ' The length of the second line segment P 2 ''P 2 '' '' is calculated by equation (4) ; Formula (3) Equation (4).
  7. 7. The analytical geometry-based steering linkage design method according to claim 1, wherein S11 specifically comprises the steps of: s111 for Solving the coordinates of the points to establish a binary quadratic equation set Distance to P 4 is equal to 、 Distance to P 2 ' is equal to Constructing an equation set shown in a formula (5) as constraint conditions, and solving the equation set to obtain ; Formula (5) S112 for Solving the coordinates of the points to establish a binary quadratic equation set Distance to P 4 is equal to 、 The distance to P 2 '' is equal to Constructing an equation set shown in a formula (6) as constraint conditions, and solving the equation set to obtain ; Equation (6).
  8. 8. The analytical geometry-based steering linkage design method according to claim 1, wherein S12 specifically comprises the steps of: S121 based on 、 、 、 Confirming that all coordinates are in a rectangular coordinate system of the same plane; s122 for the first line segment Calculating the slope and the midpoint of the first line segment; Will be And Substituting the coordinates of the first line segment into a slope formula and a midpoint coordinate formula, and respectively solving the coordinates of the slope k 1 and the midpoint M of the first line segment through a formula (7) ; Formula (7) S123, for the second line segment (P 2 ''P 2 ' ' '), calculating the slope and the midpoint of the second line segment And (3) with Substituting the coordinates of the second line segment into a slope formula and a midpoint coordinate formula, and respectively solving the coordinates of the slope k 2 and the midpoint N of the second line segment through a formula (8) ; Equation (8).
  9. 9. The analytical geometry-based steering linkage design method according to claim 1, wherein S13 specifically comprises the steps of: S131, substituting the slope k 1 of the first line segment into the slope relation based on the vertical slope of the straight line Solving to obtain the slope of the corresponding perpendicular bisector l 1 , substituting the slope k 2 of the second line segment into Solving to obtain the slope of the corresponding perpendicular bisector l 2 ; s132, using the extracted midpoint Substituting the slope of the perpendicular bisector I 1 obtained by combining the straight line passing points into the point oblique equation to obtain a I 1 straight line equation shown in the formula (11) and taking the midpoint as the midpoint Substituting a slope of a perpendicular bisector l 2 into a point oblique equation to obtain a l 2 linear equation shown in a formula (12) for a straight line passing point; Formula (11) Equation (12).
  10. 10. The steering pull rod mechanism is characterized by being designed based on the design method of the steering pull rod mechanism based on the analytic geometry, which is described in any one of claims 1 to 9, and comprises a front swing arm support (1), a front steering swing arm (2), a steering pull rod (3), a rear steering swing arm (4) and a rear swing arm support (5); The front steering swing arm (2) is connected with the front swing arm support (1) and the rear steering swing arm (4) is connected with the rear swing arm support (5) through a pin shaft; The steering pull rod (3) is hinged with the front steering swing arm (2) and the rear steering swing arm (4) respectively; The hinge points of the front swing arm support (1) and the front steering swing arm (2) are marked as P 1 , the hinge points of the front steering swing arm (2) and the steering pull rod (3) are marked as P 2 , the hinge points of the steering pull rod (3) and the rear steering swing arm (4) are marked as P 3 , and the hinge points of the rear steering swing arm (4) and the rear swing arm support (5) are marked as P4.

Description

Design method of steering pull rod mechanism based on analytical geometry and steering pull rod mechanism Technical Field 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. Background The steering pull rod mechanism is a key component part in a vehicle steering system, and has the main functions of transmitting a steering instruction input by a driver through a steering wheel to wheels, realizing wheel deflection and completing the steering action of the vehicle. The traditional steering pull rod mechanism is designed by adopting an empirical analogy method or a trial and error method, a large number of physical prototype tests and repeated adjustment are needed, the development period is long, the left and right wheels are difficult to meet the Ackerman geometric relationship in the steering process, and the problems of abnormal abrasion of tires, steering response delay or control stability reduction are easily caused. In the related art, when the space mechanism of the steering pull rod is analyzed, the multi-directional rotation degree of freedom needs to be processed, the calculation complexity is high, and the calculation of key points is easy to deviate due to the interference of non-core motion parameters. The motion synchronicity of the front steering swing arm and the rear steering swing arm lacks quantitative design basis, and the related art is approximately matched through mechanical transmission ratio, so that the adaptation relation between the length of the pull rod and the rotation angle of the swing arm in the steering process can not be accurately ensured. This can lead to front and back wheel steering angle mismatch when turning to, not only influence steering accuracy, can also let the pull rod bear extra bending or tensile stress, shorten mechanism life. Disclosure of Invention According to the analytical geometry-based steering pull rod mechanism design method, the complex steering pull rod mechanism design is converted into the computable geometric problem, the position of the key point P3 is accurately solved by using the analytical geometry method, and the design accuracy and efficiency are improved. The method comprises the following steps: s1, simplifying a steering pull rod mechanism into a plane connecting rod mechanism; S2, marking four hinge points in a plane connecting rod mechanism, wherein the four hinge points are respectively a hinge point P 1 of a front swing arm support and a front steering swing arm, a hinge point P 2 of the front steering swing arm and a steering pull rod, a hinge point P 3 of the steering pull rod and a rear steering swing arm and a hinge point P 4 of the rear steering swing arm and a rear swing arm support, and P 3 is a point to be solved; s3, establishing a plane rectangular coordinate system by taking the P 1 point as an origin; s4, acquiring the length and the initial angle of a front steering swing arm, and acquiring the coordinate of a P 4 point; S5, acquiring a front corner and a rear corner of a front steering swing arm, and acquiring the front corner and the rear corner of the rear steering swing arm; s6, determining the coordinates of the point P 2 based on the established coordinate system and the parameters acquired in the S4; S7, determining two position coordinates corresponding to a point P 2 when the front steering swing arm rotates to a front limit position and a rear limit position based on the acquired front rotation angle and rear rotation angle of the front steering swing arm, wherein the two position coordinates are respectively marked as P 2 ' and P 2 ' '; S8, calculating the distance between the P 2 'point and the P 4 point, and calculating the distance between the P 2' point and the P 4 point; S9, rotating the line segment P 2'P4 around the point P 4 in a first direction to obtain a point P 2 '' ', and rotating the line segment P 2''P4 around the point P 4 in a second direction to obtain a point P 2' ''; S10, respectively connecting the P 2 ' point and the P 2 ' ' ' point to form a first line segment, and connecting the P 2 ' ' point and the P 2 ' ' ' point to form a second line segment; S11, determining Dots and dotsCoordinates of the points; s12, determining the midpoint and the slope of the first line segment, and determining the midpoint and the slope of the second line segment; s13, respectively constructing a perpendicular bisector of the first line segment and the second line segment; and S14, calculating an intersection point of the two perpendicular bisectors, wherein the intersection point is the position of the P 3 point. It should be further noted that S5 specifically includes the following steps: s51, determining the maximum clockwise rotation angle and the maximum anticlockwise rotation angle of the front steering swing arm relative to the initial installat