Patent ID: 6652790
Filing Date: 2003-11-25
Classification: H01R

Abstract:
A method of fabricating brushes which are used in an armature provided with a commutator and that slide in contact with a plurality of segments of the commutator, a commutator surface having each of the segments being nearly orthogonal to an axis of rotation of the armature, each of the segments being inclined in relation to a direction of rotation of the armature, a plurality of the brushes having a projected form of their plane on the commutator surface that conforms to a shape of the segments, each of the brushes being formed of a first brush material produced of a first brush powder on a second brush material produced of a second brush powder, the first brush powder material being placed on a front side in a direction of rotation of the armature and the second brush material positioned on a rear side, the second brush material being set at nearly fixed values in thickness, the front end face of the first brush material being inclined to a predetermined angle in relation to the rear end face of the second brush material, method comprising:molding in a first molding process by charging a first brush onto a pressure receiving face of a lower punch; feeding down an upper punch to press the first brush powder to mold a first brush material; and molding in a second molding process by charging a second brush powder onto a top of the first brush material after the upper punch is elevated, feeding down the upper punch to mold the second brush material; wherein a molding die is used in the molding processes which has a lower die provided with a slide groove formed in an obliquely up-and-down direction, a lower punch slidably movable in an obliquely up-and-down direction along the slide groove, an upper punch slidably movable in an obliquely up-and-down direction in relation to the lower punch, and an upper die slidably movably holding the upper punch; wherein the upper punch has a pressure surface provided nearly horizontally, and the lower punch has a pressure receiving face inclined at a predetermined angle in relation to the pressure surface of the upper punch.