Electricity: measuring and testing – Magnetic – Displacement
Reexamination Certificate
2000-06-19
2002-03-12
Patidar, Jay (Department: 2862)
Electricity: measuring and testing
Magnetic
Displacement
C324S207250, C324S207220
Reexamination Certificate
active
06356073
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATION
This application is based upon Japanese Patent Application No. Hei. 11-182454 filed on Jun. 28, 1999, No. Hei. 11-298997 filed on Oct. 21, 1999, and No. 2000-55923 filed on Feb. 28, 2000, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an angular position detecting apparatus, and in particular to an angular position detecting apparatus having an improved stator core arrangement.
2. Related Art
The angular position detecting apparatus having a rotor supporting a magnet and a stator supporting a detecting element is disclosed in JP-B2-2842482, JP-A-8-35809, WO 98/08060, U.S. Pat. No. 5,861,745 and DE 19634281 A1. For example, the angular position detecting apparatus detects an opening degree of a throttle valve (an opening degree of a throttle) of an internal combustion engine.
SUMMARY OF THE INVENTION
FIG. 22
shows a prior work by the inventor. As shown in
FIG. 22
, a stator core
12
is concentrically arranged at an inner side of a cylindrical rotor core
11
, which integrally rotates with a throttle valve (not-shown). Two permanent magnets
13
having a circular arc shape are fixed to the inner side of the rotor core
11
so as to confront each other and sandwich the stator core
12
. Each of the permanent magnets
13
is radially magnetized so that all of lines of magnetic force in the permanent magnets
13
are set to a radial direction. Incidentally, a gap portion
14
having a constant width for detecting a magnetic flux is formed at a center portion of the stator core
12
so as to open along a diametric direction. A detecting element
15
such as a Hall IC is provided in the gap portion
14
. According to this structure, since a magnetic flux density passing through the gap portion
14
of the stator
12
(magnetic flux density passing through the detecting element
15
) changes in proportion to the angular position of the rotor core
11
, and since output of the detecting element
15
changes in proportion to the magnetic flux density, the angular position of the rotor core
11
(angular position of the throttle valve) is detected based on the output of the detecting element
15
. As shown in
FIG. 22
, the gap portion
14
has a constant width and the detecting element
15
occupies only a part of the gap portion
14
. Therefore, the detecting element
15
only detects a part of the magnetic flux which passes through the gap portion
14
. Therefore, a powerful or large magnet, or a signal processing circuit having a high gain amplifier is required to achieve a sufficient signal indicating an output of the detecting element
15
.
This invention has been conceived in view of the background thus far described and its first object is to provide an improved angular position detecting apparatus.
Its second object is to provide an improved angular position detecting apparatus out putting a sufficient level of signal from a detecting element.
Its third object is to provide an improved angular position detecting apparatus having a stator core for concentrating a magnetic flux into the detecting element.
Its fourth object is to provide a stator core arrangement for concentrating the magnetic flux into the detecting element without decreasing a detecting range.
According to one aspect of the present invention, a gap portion formed in a stator has a detecting portion which is a gap having a small distance and a large gap portion having a distance wider than the detecting portion for concentrating the magnetic flux into the detecting portion. Therefore, a detecting element arranged in the gap portion detects a concentrated magnetic flux and outputs a sufficient signal.
REFERENCES:
patent: 5528139 (1996-06-01), Oudet et al.
patent: 5789917 (1998-08-01), Outdet et al.
patent: 5861745 (1999-01-01), Herden
patent: 6043645 (2000-03-01), Outdet et al.
patent: 196 34 281 (1998-02-01), None
patent: 196 34 282 (1998-02-01), None
Hamaoka Takashi
Kono Yoshiyuki
Kubota Takamitsu
Denso Corporation
Nixon & Vanderhye PC
Patidar Jay
Zaveri Subhash
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