Emission control valve having a robust solenoid actuator
AssigneeSiemens VDO Automotive Corporation
InventorRussell Modien
Life of this patent
Estimating the term…
Abstract
An automotive emission control valve, an EGR valve in particular, has a solenoid for operating a valve element. The solenoid has a stator and an armature. A shaft is pressed into a through-hole in the armature. Ends of the shaft that protrude from the armature are guided by bearings that are fit to upper and lower pole pieces of the stator.
Claims11
An emission control valve for controlling flow of gases with respect to combustion chamber space of an internal combustion engine comprising:
- a valve body comprising a passageway having an inlet port for receiving gases and an outlet port for delivering gases to the combustion chamber space;
- a valve element that is selectively positioned to selectively restrict the passage;
- and
- a mechanism for selectively positioning the valve element comprising a solenoid having an electromagnet coil bounding an interior space, a stator that is associated with the coil and that has a magnetic circuit for conducting magnetic flux generated in the stator when electric current flows in the coil, including an air gap disposed within the interior space bounded by the coil, and an armature that is disposed at the air gap and displaced along an imaginary centerline by the magnetic flux to position the valve element;
- a shaft that is pressed into a central axial through-hole in the armature to create a shaft-armature assembly wherein opposite end portions of the shaft protrude from opposite ends of the through-hole;
- and bearings for guiding displacement of the shaft-armature assembly along the centerline comprising an annular lower bearing that is fit to a lower pole piece of the stator and an annular upper bearing that is fit to an upper pole piece of the stator;
- wherein the shaft-armature assembly, the upper pole piece, the lower pole piece, and the electromagnet coil are arranged in an assembled relationship to dispose the armature within the interior space bounded by the coil with the end portions of the shaft passing through respective central through-holes in the bearings concentric with the imaginary centerline and with the pole pieces disposed at opposite ends of the coil to create the air gap within the coil interior space and to associate the pole pieces with additional stator structure that conducts magnetic flux between the pole pieces external to the coil interior space.
A method of making an emission control valve that has a valve body comprising a passageway having an inlet port for receiving gases and an outlet port for delivering gases to the combustion chamber space, a valve element that is selectively positioned to selectively restrict the passage, and a mechanism for selectively positioning the valve element comprising a solenoid having an electromagnet coil bounding an interior space, a stator that is associated with the coil and that has a magnetic circuit comprising an air gap for conducting magnetic flux generated in the stator when electric current flows in the coil, and an armature that is disposed in the air gap to be displaced along an imaginary centerline by the magnetic flux for positioning the valve element, the method comprising:
- pressing a shaft into a central axial through-hole in the armature to create a shaft-armature assembly wherein opposite end portions of the shaft protrude from opposite ends of the through-hole;
- fitting an annular lower bearing having a central through-hole to a lower pole piece of the stator to create a lower bearing-pole piece assembly;
- fitting an annular upper bearing having a central through-hole to an upper pole piece of the stator to create an upper bearing-pole piece assembly;
- assembling the shaft-armature assembly, the upper bearing-pole piece assembly, the lower bearing-pole piece assembly, and the electromagnet coil to dispose the armature within the interior space bounded by the coil with the end portions of the shaft passing through the bearing through-holes concentric with the imaginary centerline and with the bearing-pole piece assemblies disposed at opposite ends of the coil to create the air gap within the coil interior space and to associate the pole pieces with additional stator structure that conducts magnetic flux between the pole pieces external to the coil interior space.
Dependencies are inferred from the claim text.