Analysis And Research On Dimension Deviation Of Engine Room Compartment

Engine room compartment is an important assembly of BIW (Body in White), the quality of engine room compartment directly impacts the quality of BIW. Research on the deviation of engine room is of great significance. However, the engine room welding assembly is a multi-station and multi-level assembly, the dimension chain of the assembly process is three dimensional, its accumulate rule is complex. Under this background, the software3DCS is used to analyze engine room compartment assembly error. The engine room compartment variation is calculated by means of virtual simulation. Fault diagnosis theory is used to analyze the root cause. The main contents of this article are shown as follows:(1) Space state method is used to represent the assembly process in3-D space. The assembly process in3-D space is more complex than in1-D space, and the deviation propagation paths are more complex, the traditional1-D formula does not fit3-D calculation. Therefore, a new formula should be established to express3-D assembly. The state space model shows the relationship between assembly deviation and component deviation accurately,(2) The assembly quality evaluation method is shown. There are many important mounting holes on the engine room compartment. The quality of these mounting holes determines the welding quality of the compartment. The quality of the compartment is evaluated by measuring the false ratio,6a value, PP and Ppk values of the dimensions of these holes.(3) Assembly deviation is calculated and verified. The software3DCS is used to calculate the assembly deviation, and the result is verified by measuring result.(4) Deviation source diagnosis of the engine compartment is promoted. Deviation source diagnosis is an important part of deviation analysis. It’s easy to identify the root cause of the assembly deviation. Results of deviation diagnosis are the important references in optimization.