Electromagnetic relay, method of adjusting the same, and method of assembling the same

A method of adjusting an electromagnetic relay having

• a spool having a hollow portion,
• a coil wound on said spool,
• a U-shaped yoke having a magnetic pole surface on one end thereof and fixed to two end portions of said spool,
• an armature movably connected to one end of said yoke and positioned to extend through said hollow portion of said spool,
• a movable contact attached to move in an interlocked manner with said armature, and
• a pair of stationary contacts arranged to sandwich said movable contact and including a making contact,
• comprising the steps of:
• pushing said yoke into said spool until reaching a temporary fixing position,
• exciting said coil at said temporary fixing position, thereby maintaining a predetermined gap between said armature and said magnetic pole surface of said yoke, and
• determining a press-fit position of said yoke, while said predetermined gap is maintained, in accordance with presence/absence of contact between said movable contact and said making contact, thereby adjusting a contact follow.

A method of assembling an electromagnetic relay, comprising the steps of:

• temporarily fixing a U-shaped yoke to two end portions of a spool, having a coil, by press fitting;
• forming an integral structure in which a proximal end portion of an armature extending through a hollow portion of said spool is connected to one end of said yoke and a spring member, which biases said armature in such a direction that a distal end portion thereof opens from the other end of said yoke, is fixed to said yoke and said armature;
• press-fitting one end of said yoke into a first flange portion of said spool, and temporarily fixing said yoke such that the other end of said yoke pivots about one end of said yoke as a rotation center;
• and
• after temporary fixing, with a distance between the other end of said yoke and a distal end portion of said armature being maintained to a predetermined value, press-fitting said yoke into said second flange of said spool while adjusting the other end of said yoke.