Patent ID: 9424972
Filing Date: 2016-08-23
CPC Classification: F02N,H01F,H02K

Claim Text:
1. A solenoid for a vehicle starter, the solenoid comprising: at least one coil with a passage extending through the coil in an axial direction, the at least one coil configured to generate a magnetic circuit; and a ferromagnetic plunger configured to move in the axial direction within the passage when a magnetic force related to the magnetic circuit is applied to the plunger, the plunger including a cylindrical outer surface with a substantially uniform diameter and a circumferential notch, the cylindrical outer surface defining a first portion with a first diameter on one side of the circumferential notch, and a second portion with the first diameter on an opposite side of the circumferential notch, the circumferential notch defining a portion with a second diameter that is less than the first diameter, the first portion having an axial length that is greater than an axial length of the at least one coil, wherein the plunger does not include a permanent magnet, and wherein a reluctance of the magnetic circuit and the related magnetic force applied to the plunger varies based on a position of the circumferential notch as the plunger moves in the axial direction within the passage, the plunger configured to move in the axial direction between a first position where the first portion of the plunger is removed from a plunger stop and a second position where the first portion of the plunger engages the plunger stop.