Actuator having a permanent magnet

Details Actuator having a permanent magnet Actuator having a permanent magnet

2002-09-24

2004-09-07

Nguyen, Tran (Department: 2834)

Electrical generator or motor structure

Dynamoelectric

Linear

C335S222000, C335S229000, C310S012060

Reexamination Certificate

active

06787946

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to evaporative emission control systems for internal combustion engines, and more particularly, to an actuator having a permanent magnet for increasing armature force and displacement.
BACKGROUND OF THE INVENTION
Many motor vehicles utilize actuators such as solenoids to operate several types of devices. This includes devices such as a fuel cell valve or an exhaust gas recirculation (EGR) valve used in an EGR system. In such systems, the EGR valve is controlled by a circuit in accordance with various engine operating conditions to regulate the amount of engine exhaust gas that is recirculated back into the engine for combustion. This serves to limit the combustion temperature and hence reduce the formation of oxides of nitrogen.
Solenoids typically utilize an electromagnet coil to generate a magnetic force which causes an armature to move along an axis. The armature may be part of a mechanism for operating a valve, such as an EGR valve. Referring to
FIG. 1
, an enlarged view of a first magnetic flux density
10
located near portions of a lower stator
12
, upper stator
46
, gap
36
, first armature
14
and coil
16
of a conventional solenoid is shown. It is noted that the configuration shown is substantially symmetrical about an axis of the solenoid and that only one side of the axis is shown for purposes of clarity. The lower stator
12
has a frusto-conical shape having a predetermined geometry and is separated from the upper stator
46
by a gap
36
. The shape of the lower stator
12
along with the size of the gap
36
and other parameters are selected so as to optimize a flux path that forms a part of a magnetic circuit. This provides a desired solenoid characteristic in that the armature force is substantially constant with respect to armature displacement. Referring to
FIG. 1
, the magnetic flux density vectors are oriented in a substantially clockwise configuration in a lower portion
18
of the first armature
14
adjacent to the lower stator
12
. In addition, the magnetic flux density vectors are relatively dispersed along an edge
20
of the lower portion
18
. In this configuration, the magnetic flux density in an upper section
22
of the lower stator
12
ranges from approximately 1597 to 2195 kiloGauss (kGauss).
It is desirable that solenoids used in motor vehicles provide increased armature force and increased travel so as to improve controllability and increase flow. However, this would require larger solenoids and the amount of space available in current vehicle engine compartments is limited.
SUMMARY OF THE INVENTION
A solenoid which includes a housing having a coil for generating a first magnetic field. An armature is slidably mounted in the housing. The solenoid further includes a permanent magnet having a second magnetic field, wherein the magnet is located adjacent the armature. In addition, a stator is affixed in the housing for cooperation with the armature and the magnet to form a third magnetic field.
The features of the invention believed to be novel are set forth with particularity in the appended claims. The invention itself, however, both as to organization and method of operation, may be best understood by reference to the following description taken in conjunction with accompanying drawings.


REFERENCES:
patent: 3772540 (1973-11-01), Benson
patent: 4677327 (1987-06-01), Kushida et al.
patent: 5734209 (1998-03-01), Hallidy
patent: 6051896 (2000-04-01), Shibuya et al.
patent: 6280124 (2001-08-01), Ammann

Affiliated with

Also associated with

Rating

Actuator having a permanent magnet does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Actuator having a permanent magnet, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Actuator having a permanent magnet will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3229804