EV High-Voltage Junction Box Tolerance Compensation Assembly
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Solution Overview
Problem
High-voltage junction boxes in electric vehicles face challenges with large tolerances between components, leading to mechanical and electrical stress during assembly and potential damage during contactor replacement, as these tolerances cannot be balanced without applying tension to the connector and bus bar.
Innovation Solution
Incorporating a tolerance compensation element in the mounting hole between the housing and contactor, allowing for size variation compensation, ensuring a fixed position of the contactor and bus bar independent of original dimensions, thus preventing stress on the connector and bus bar during replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the contactor is fixed to the housing by screws directly, then the assembly is simple, but large tolerances cause considerable gaps and high tensions applied to the connector and bus bar
Solution Approach 1:
A tolerance compensation element is introduced as an intermediary component between the housing and the contactor. This element absorbs the tolerance variations and prevents direct transmission of mechanical stresses to the connector and bus bar, thereby maintaining reliable electrical connections while keeping the assembly relatively simple.
Solution Approach 2:
The tolerance compensation element allows for adjustments in the mounting distance between the housing and the contactor. By changing the effective mounting parameter (distance), the system can accommodate tolerance variations in the contactor dimensions without creating excessive gaps or tensions in the electrical connections.
2Manufacturing precision
If tolerance balancing is attempted during assembly, then some tolerances may be compensated, but replacement contactors with different dimensions cannot be balanced without applying tension to the contactor, bus bar and connector
Solution Approach 1:
The tolerance compensation element serves as a mediator that decouples the replacement contactor from the housing. This allows the contactor to be replaced without requiring precise tolerance balancing, as the compensation element absorbs the dimensional differences between replacement contactors and the original component.
Solution Approach 2:
The tolerance compensation element provides dynamic adjustment capability, allowing the mounting distance to be optimized for each specific contactor instance. This dynamic adaptation enables easy replacement of contactors with varying dimensions without creating mechanical or electrical stress.
3Ease of operation
If the contactor position is not fixed relative to the housing, then assembly is easier, but the position of the bus bar and connector varies with contactor tolerances causing electrical and mechanical stress
Solution Approach 1:
The tolerance compensation element acts as a mediator that enables easy assembly while simultaneously maintaining a fixed position of the contactor relative to the housing. This fixed positioning ensures that the bus bar and connector connections remain stable and free from stress, preserving electrical and mechanical integrity.
Solution Approach 2:
The tolerance compensation element provides beforehand cushioning against position variations. By pre-absorbing the tolerance variations in the contactor dimensions, it prevents the transmission of positional variations to the bus bar and connector, thereby maintaining reliable connections during assembly and operation.
Data Source
AI summary
A high-voltage junction box for an electrically driven vehicle includes a housing part with at least one mounting hole, a contactor mechanically connected to the housing part by at least one fastening element extending through a through hole in the contactor into the mounting hole, and a bus bar having a first contact area and a second contact area. The first contact area is electrically and mechanically connected to the contactor and the second contact area is electrically and mechanically connected to a connector. A tolerance compensation element suitable to compensate for tolerance variations in a distance or space between the housing part and the contactor is mounted in the at least one mounting hole. An electrically driven vehicle with a charging unit including a high-voltage junction box is also provided.