The principle and application of positioning of automobile modification parts
With the development of the economy and the improvement of people's living standards, automobiles have been widely used in people's daily life, which has driven the development of the automobile industry and the improvement of related technologies, and people have put forward higher requirements for the functions and quality of automobiles . In order to improve the quality and performance of the car, we must pay attention to the positioning of titanium modified car parts. The assembly positioning of auto parts affects the stability and service life of the car, and is an important link in the automobile manufacturing process. The positioning principle should be followed when the parts are assembled.
1. The principle of space rectangular coordinates Auto parts are designed in the three-dimensional space coordinate system, so as a free rigid body, the titanium modified car parts manufacturers move along the X, Y, and Z coordinate axes in the three-dimensional rectangular coordinate system and decompose them into translational degrees of freedom. , the rotation around the X, Y, Z coordinate axes is decomposed into rotational degrees of freedom, that is, any auto part has six degrees of freedom. If the auto parts want to be firmly positioned, they need the mutual cooperation between the auto parts to limit these six freedoms. degree to achieve the positioning of auto parts. The six-point positioning principle is an important principle in the assembly and positioning of automobile parts, that is, points are used to limit the spatial degrees of freedom of parts, followed by lines to limit the spatial degrees of freedom of parts, and finally surfaces can be considered. When applying the positioning principle, attention should be paid to the wear and deformation of automobile parts. When using positioning points to limit the parts, there should be no zero distance limit, but a distance of 0.1~0.2 mm. In addition, the strength of the parts needs to be considered when assembling and positioning automobile parts, and the number of positioning points is determined according to the strength of the parts. Not all parts must be positioned with 6 positioning points, which is the principle of incomplete positioning and over-positioning. Incomplete positioning means that the limit points are less than six and do not affect the function and performance of the parts. For example, parts such as armrest boxes and glove boxes of automobiles are commonly used in this positioning method. Over-positioning refers to positioning with multiple limit points in order to strengthen the positioning effect, which is suitable for positioning of large-sized and easily deformed parts. For example, the matching structure of the high-position brake light and the rear wing adopts two parts for Z-direction positioning and one part for Y-direction positioning, which is to prevent the deformation of the high-position brake light from causing uneven positioning of the left and right endpoints.
2. Design principle of datum plane and datum hole The datum is the point, line or surface used to determine the geometric relationship of auto parts. The datum surface of automobile parts is required to be flat, large, and dimensionally stable, and certain deviations are allowed. The accuracy of the datum surface must be able to match the function of the applied parts. Face the accuracy requirements, such as the mating surface of the assembly and the gap level difference to form the face datum surface The precision requirements are different, and the manufacturing process cost is also saved. There are H2S and H2H design schemes for the design of the reference hole. The H2S scheme has a circular reference hole, which controls 4 orientations and limits two plane degrees of freedom. A long datum hole, limited to two orientations, 1 rotational degree of freedom. H2H has two reference holes for circles with different position tolerances and controls 4 orientations, which is essentially an over-positioning. The H2S solution is often applied to parts with strong rigidity and large dimensional deviations such as interior and exterior parts such as beams, sheet metal assembly parts, subframes, and front skins. H2H is often used in single thin sheet metal parts such as side wall outer panels and B-pillar inner panels. Both of these schemes are aimed at reducing the deviation of the production of titanium modified cars.
Company: Baoji Dynamic Trading Co., Ltd
Country:China
Add:Baoti road,Jintai,Baoji city,Shaanxi,China
Cel:+86 18391896637(WHATSAPP)
Gmail:alisa@jmyunti.com
Website:www.jm-titanium.com
