Built-in main fixture

Abstract

The invention relates to a built-in main fixture. The built-in main fixture consists of a lower vehicle body positioning fixture, a built-in fixture body, a lifting system and a switching system. The built-in main fixture is characterized in that: a four-point positioning mode is adopted between the built-in fixture body and the lower vehicle body positioning fixture, and the centers of four positioning points are positioned in the center of gravity of the built-in fixture body so as to ensure that the positioning error is furthest eliminated in the positioning process; and two round hook pins and two rhombic hook pins are arranged on the four positioning points, and achieve a guiding effect in the descending process of the built-in fixture body so as to eliminate the positional deviation generated in the descending process. When the built-in fixture body descends to the appropriate position, the hook pins position the built-in fixture body, so that the fit precision between the built-in fixture body and the lower vehicle body fixture is ensured to be within + / -0.05mm. The built-in main fixture can stably and quickly ascend and descend, and can better ensure the dimensional accuracy of a vehicle body; meanwhile, a complete set of built-in fixture switching mechanism can also realize the multi-vehicle-type mixed flow production, and the switching time between vehicle types is short, so that the production beat is promoted. The cost and period of the retrofit of a production line during the replacement of new and old vehicle types are reduced; and a split structure of the built-in main fixture can better control the dimensional accuracy of the vehicle body, so that the aim of producing C class high-end cars is fulfilled.

Description

technical field [0001] The invention relates to a built-in main fixture, which is used for the main assembly fixture system of an automatic production line with mixed flow of multiple models. Background technique [0002] Along with economic development, automobile has increasingly become a means of transportation for people to travel. In the domestic automobile market, with the rise of China's automobile industry and the development trend of more models and less batches, especially the boom in the domestic automobile market in the past two years, various automobile companies are scrambling to build new production lines to expand production capacity. [0003] Production capacity and quality are the two major indicators of the production line. Similarly, as the most important controller of dimensional accuracy in the body-in-white welding assembly - the main assembly fixture has become a key factor to increase production capacity and ensure body quality. [0004] The main fi...

AI Technical Summary

Problems solved by technology

[0005] The current external fixtures mainly have the following disadvantages: the reusability of the external fixtures is poor when the product is modified, and in terms of cost and project cycle, it is generally chosen to manufacture a new set of main assembly fixtures to correspond to new models; It is divided into left and right parts, and the body is clamped from the side translation. The relative accuracy between the left and right parts is difficult to measure and guarantee; Combining workstations requires a large area and takes a long time to switch between models

[0006] The current built-in clamps are mainly adopted by Toyota Corporation of Japan, which mainly has the following disadvantages: the overall positioning surface is on the upper part of the body, and the size control of the lower part of the body is poor; the ordinary SMC cylinder is used, which has no self-locking function and cannot be better controlled. Body precision and avoiding the risk of fixture damage due to sudden air cut-off in the production line

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