Analysis And Control Research On Contact Welding Bonding For TO-5 Relay

Relay contact bond failure is a conventional failure mode of relay.In the use of electromagnetic relay,the failure of control function is usually caused by the failure of contact bonding.According to the failure phenomenon statistics of electromagnetic relays used on military complete machines such as spaceflight,aviation,weapons and ships,the welding and bonding of contact points is one of the main problems leading to the failure of relays,accounting for more than 30% of all the bonding problems.In order to improve the reliability of the relay and ensure the military application requirements,this thesis studies the mechanism and conditions of the contact resistance variation of the relay contacts,and intends to find out the effective methods and measures to control the welding and bonding of the contacts.In this thesis,studying the influence of the movable parts of the TO-5 electromagnetic relay on the welding and bonding of the contacts in depth,and by improving the coil assembly ampere turn to improve retention,optimize the quality of armature magnetic system reduce the armature rebound,set the armature main pole face and improve the electromagnetic suction magnetic system and optimization of dynamic and static contact spring and moving contact spring stiffness matching optimization improvement measures,such as a significant reduction in the armature jumped and contact bounce to back,reduce the probability of relay contact welding bonding,improve the reliability of the product.Aiming at the influence of contact pair of TO-5 electromagnetic relay on welding and bonding of contact,this thesis carried out research on contact form of the contact,coating of the contact and vibration electroplating process control technology to improve the coating of the contact to gilt cobalt and adopt vibration electroplating technology,and the arc ablative resistance of the contact can also be improved.In this thesis the TO-5 electromagnetic relay internal seals internal gas composition of cavity,the technical research,through analyzing the composition of the contact materials contact material of zinc and oxygen under the condition of high temperature oxidation with high melting point,arc corrosion resistance of zinc oxide,it can improve the contact arc corrosion resistance ability,so as to reduce the probability of contact welding products,and ensure product life performance.Finally,the optimized control measures were adopted to install and verify the relay products in test batch and batch production,and the screening and example test of group A and group B were carried out according to the detailed specifications of the products,and the pulling test was carried out for the product life.The life load current and life times were both increased by one time compared with those before the improvement.It is proved that it is necessary to reduce contact bounce,improve coating of the contact and optimize internal gas composition in relay to improve the welding and bonding resistance of contact.