Insulated Push Rod Contact Structure for Coil-to-Contact Isolation
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Solution Overview
Problem
Conventional electromagnetic switches in electric vehicles lack adequate insulation between high-voltage and low-voltage components, posing a significant safety risk due to electrical spacing and creepage distance inadequacies, which can lead to safety accidents during switching of large-current and high-voltage loads.
Innovation Solution
A contact apparatus with a fixed and moving contact component, featuring an insulated sleeve on a push rod and a contact spring, ensures electrical isolation between the high-voltage and low-voltage coils by fully insulating the push rod from the moving contact, preventing damage to the low-voltage coil part during high-voltage switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional epoxy package and ceramic packages are used for electromagnetic switch, then the device complexity is reduced, but the electrical spacing and creepage distance between high-voltage contact system and low-voltage coil system are insufficient, leading to safety risks
Solution Approach 1:
The push rod is segmented into multiple parts: a first push rod portion (conductive, connected to high-voltage contact), a second push rod portion (insulating, connected to low-voltage coil), and a connecting portion. This segmentation physically separates the high-voltage and low-voltage pathways, ensuring adequate electrical spacing and creepage distance while maintaining the mechanical pushing function, thereby resolving the safety risk without significantly increasing device complexity
Solution Approach 2:
An insulating sleeve is introduced as an intermediary component between the first push rod portion (high-voltage side) and the second push rod portion (low-voltage side). This insulating sleeve acts as a mediator that prevents direct electrical contact between high-voltage and low-voltage systems, ensuring proper electrical spacing and creepage distance while allowing mechanical force transmission, thus improving safety reliability without major complexity increase
2Reliability
If insulation measures are added to isolate high-voltage and low-voltage systems, then the safety reliability is improved, but the device complexity increases
Solution Approach 1:
The insulating function is merged with the existing push rod structure by making the second push rod portion itself insulating, rather than adding a separate insulating component. The connecting portion integrates both mechanical connection and electrical insulation functions. This merging approach achieves the required electrical isolation while minimizing the increase in device complexity
Solution Approach 2:
The second push rod portion serves multiple functions: it transmits mechanical force from the first push rod portion, provides electrical insulation between high-voltage and low-voltage systems, and maintains the structural integrity of the push rod assembly. This multi-functionality reduces the need for additional dedicated insulating components, thereby improving safety reliability without proportionally increasing device complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively isolates the low-voltage coils from high-voltage and large-current impacts, enhancing the safety reliability of the electromagnetic switch by preventing breakdowns between high and low voltages, thus reducing the risk of safety accidents.
Implementation Method 1
The contact spring elastically abuts between the moving contact and the contact bracket
Implementation Method 2
the insulated sleeve can insulate the push rod from the moving contact
Implementation Method 3
a current flows through coils to generate a magnetic field to switch on/off a contact, thereby controlling a load
Data Source
AI summary
A contact apparatus includes a fixed contact and a moving contact component. The moving contact component includes a push rod, a contact bracket, an insulated sleeve, a moving contact, and a contact spring. The insulated sleeve is fixedly sleeved on a first end of the push rod, a second end of the push rod is configured to connect a drive apparatus, the contact bracket is fixedly sleeved on the insulated sleeve, the moving contact and the contact spring are both flexibly sleeved on the insulated sleeve, the contact spring elastically abuts between the moving contact and the contact bracket, the moving contact and the fixed contact are disposed relative to each other in an extension direction of the push rod, and the moving contact can be driven by the push rod to be connected to the fixed contact.