GB1442601A - Starter motors - Google Patents

Abstract

1442601 Electric starters for internal combustion engines LUCAS ELECTRICAL Ltd 19 Oct 1973 [10 Nov 1972] 51994/72 Heading F1K A starter for an internal-combustion engine comprises an electric motor 11, a shaft 12 rotatable by the motor and carrying a starter pinion 15, the starter pinion being rotatable with the shaft and being movable axially relative to the shaft between a rest position and an operative position and an electromagnet including an armature 17 coupled to the starter pinion, the armature and the starter pinion being movable axially relative to the shaft, a plurality of electromagnetic poles 21 equi-angularly spaced around the axis of the shaft in a plane at right angles to the axis and spaced apart radially by an amount such that the armature can enter between the poles during its axial movement, the poles being spaced from the armature in the rest position thereof in the direction of movement of the armature, each pole being shaped so that the surface of each pole presented to the armature in the rest position of the armature includes regions spaced from the armature by different distances in the direction of movement of the armature and equally spaced from the shaft in a radial direction, a member 13 magnetically inter-connecting the poles and an electromagnet winding 20 associated with the poles so that when energized the winding induces a flow of magnetic flux between the poles and the armature within the armature at right angles to its direction of movement and between the poles by way of the member so that the armature is attracted to the poles, the arrangement of the regions of the pole surfaces being chosen to achieve a predetermined attraction between the poles and the armature during the movement of the armature towards the poles. A number of different pole shoes are described with reference to Figs. 4 to 11 (not shown). As shown a winding 20 is associated with each pole. The windings 20 will normally be energized by way of a manually controlled switch which simultaneously or after a short delay energizes the motor fit Alternatively the motor 11 can be energized by a further switch dependent on movement of the armature to a position corresponding to the operative position of the pinion 15. More than two equi-angularly spaced poles may be utilized.