Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Reexamination Certificate
2001-12-05
2004-05-25
Gimie, Mahmoud (Department: 3747)
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
C251S305000, C251S129110
Reexamination Certificate
active
06739315
ABSTRACT:
This application is based on Application No. 2001-162100, filed in Japan on May 30, 2001, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a throttle valve control device for an internal combustion engine in which the rotation of a motor corresponding to an amount of operation of an accelerator pedal is transmitted through a gear mechanism to a shaft of a throttle valve, which adjusts the amount of intake air sucked into the internal combustion engine.
2. Description of the Related Art
FIG. 7
is a cross sectional side view of a known throttle valve control device for an internal combustion engine. This throttle valve control device for an internal combustion engine includes a housing
1
, a motor
2
provided in the housing
1
, a small gear wheel
4
fixed to a rotating shaft
3
of the motor
2
, an intermediate gear wheel
5
in mesh with the small gear wheel
4
, a sector gear
6
in mesh with the intermediate gear wheel
5
, a shaft
7
rotatably mounted on the housing
1
across an intake passage formed therein with the sector gear
6
fixedly attached thereto at its one end, a throttle valve
8
fixedly mounted on the shaft
7
for rotation therewith, a return spring
9
for urging the throttle valve
8
in its closing direction at all times through the shaft
7
, and an opening sensor
10
fixedly attached to the shaft
7
on one side of the sector gear
6
opposite the throttle valve
8
for detecting the opening of the throttle valve
8
.
FIG. 8
is a front elevation of the sector gear
6
, and
FIG. 9
is a cross sectional view along line IX—IX of the sector gear
6
of FIG.
8
. The sector gear
6
is comprised of a generally sector-shaped core member
11
and a resin molded portion
13
with teeth
12
formed on the core member
11
by means of insert molding. The core member
11
is formed by pressing a metal sheet. The metal sheet is used for ensuring the proper strength of the sector gear
6
.
FIG. 10
is a front elevation of a sector gear
15
of another example, and
FIG. 11
is a cross sectional view along line XI—XI of the sector gear
15
of FIG.
10
. This sector gear
15
is formed on the whole by sinter molding a ferrous material.
With the known sector gear
6
as described above, the resin molded portion
13
having the teeth
12
is formed on the core member
11
by means of insert molding, but in this case, there arises a problem that a molding sink
16
as shown by a dotted line in
FIG. 12
is caused on the tooth surfaces
12
a
of the teeth
12
under the action of shrinkage occurring upon hardening of the resin, whereby the tooth surfaces or crest surfaces
12
a
are caused to incline in a diametral or radial direction from a horizontal line, as illustrated in
FIGS. 13A and 13B
.
In addition, with the sector gear
15
which on the whole is molded by sintering, inclinations of the tooth surfaces of the teeth
12
can be avoided, and hence the sector gear
15
is improved in accuracy and reliability, but gives rise to another problem that the weight of the sector gear
15
is substantially increased.
SUMMARY OF THE INVENTION
The present invention is intended to obviate the problems as referred to above, and has for its object to provide a throttle valve control device for an internal combustion engine which has a sector gear with improved teeth accuracy by preventing inclinations of the teeth surfaces.
Bearing the above object in mind, the present invention resides in a throttle valve control device for an internal combustion engine comprising a motor and a sector gear operatively connected with the motor for driving a shaft having a throttle valve fixedly mounted thereon, the sector gear including a sector-shaped core member and a resin molded portion with teeth formed on the core member by insert molding. The throttle valve control device is characterized in that the core member has a support portion with a curved surface formed to extend along bottoms of the teeth and project in an axial direction.
The above and other objects, features and advantages of the present invention will become more readily apparent to those skilled in the art from the following detailed description of preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 6092506 (2000-07-01), Takagi et al.
patent: 6173939 (2001-01-01), Dottavio et al.
patent: 2000-282898 (2000-10-01), None
“Gears from Scratch” by Paul Sharke; Dec. 2001, Mechanical Engineering.*
Palomar Integral Field Spectrograph (PIFS) webpage dated Aug. 18, 1998 by Tom Murphy et al. at California Institute of Technology.
Kurita Kazuhisa
Moriguchi Teruhiko
Nakao Kenji
Castro Arnold
Gimie Mahmoud
Mitsubishi Denki & Kabushiki Kaisha
Sughrue & Mion, PLLC
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