Modeling method for variable-ratio racks in thickened-sector rack pair of variable-ratio steering gear

Abstract

The invention discloses a modeling method for variable-ratio racks in a thicken-sector pair of a variable-ratio steering gear. The modeling method comprises the steps that in radial cross sections atequal intervals in a involute thickened sector from a large end to a small end, between tangent lines which are on a gear sector gear side and parallel to the length direction of the racks of a gear sector base circle and an addendum circle, a straight line set which is formed by straight lines at equal intervals and parallel to the length direction of the racks is generated; an intersected spot calculation equation is built; a gear sector steering angle step length is preset; after displacement of each rack is calculated according to a variable ratio curve, intersected spots of the straight lines in the straight line set and a gear sector gear contour when the straight lines and the racks are fixedly connected for moving are calculated; among the intersected spots of the same straight line and the same gear contour, a spot on which coordinate values in the length direction of the racks are extremal is selected as an initial value of a variable ratio gear contour spot; a variable ratiogear contour spot solving mathematical model is built, and optimum solutions of variable ratio gear contour spots in each radial cross section are solved; and a variable ratio gear contour spot cloudis matched, and a variable ratio rack solid model is built. By adopting the modeling method, multiple defects of a traditional modeling method are avoided, and modeling precision is higher.

Description

technical field [0001] The invention belongs to the technical field of mechanical transmission, and in particular relates to a modeling method for a variable ratio rack in a variable ratio steering gear thickened sector rack pair. Background technique [0002] The steering transmission ratio determined by the steering gear of the car is an important factor affecting the steering performance of the car. Generally speaking, when the car is running straight at high speed, in order to ensure the driving stability, the expected steering transmission is relatively large; The common requirement of steering is "variable gear ratio". The mechanical variable ratio steering gear is based on the traditional mechanical fixed ratio steering gear, changing the shape of the tooth profile of the steering rack (gear), and through the meshing of the variable ratio rack (gear) and the involute gear (rack) It realizes variable ratio steering without changing the original structure and control ...

AI Technical Summary

Problems solved by technology

Based on the machining principle of gears, the variable-ratio rack (gear) solid model established by Boolean subtraction algorithm has obvious cutting marks on the tooth profile, which is a discontinuous surface, and the modeling accuracy is very poor; the meshing principle is used to solve the variable-ratio rack (Gear) tooth profile, when the overlap ratio of the variable ratio gear and rack pair is greater than 1, the solution to the established meshing equation is not unique, and the real variable ratio tooth profile points are difficult to identify and determine

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