Machine element or mechanism – Engine starters
Reexamination Certificate
2001-10-16
2003-11-18
Bucci, David A. (Department: 3682)
Machine element or mechanism
Engine starters
Reexamination Certificate
active
06647812
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATION
This application is based upon and claims benefit of priority of Japanese Patent Application No. 2000-373758 filed on Dec. 8, 2000, the content of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a starter motor having an intermediate gear, in which a rotational torque of an output shaft of a motor is transferred to an internal combustion engine through an intermediate gear.
2. Description of Related Art
An example of the starter motors of this kind is disclosed in JP-U-50-91643. The intermediate gear structure disclosed in this publication is briefly shown in
FIGS. 4A and 4B
attached to this specification. As shown in
FIG. 4A
, an intermediate shaft
110
is disposed in parallel to an output shaft
100
of a motor. The intermediate shaft
110
rotatably supports an intermediate gear
130
that engages with a pinion
120
supported on the output shaft
100
and rotated by the motor. A coupler
140
that connects the pinion
120
to the intermediate gear
130
to slidably drive the intermediate gear
130
in an axial direction of the intermediate shaft
110
together with the pinion
120
is disposed in circular grooves
121
,
131
formed on both the pinion
120
and the intermediate gear
130
.
To start up the internal combustion engine, the pinion
120
is shifted rightward in
FIG. 4A
, and the intermediate gear
130
is also shifted rightward together with the pinion
120
, thereby engaging with a ring gear
150
of the engine. The rotational torque of the motor is transferred to the ring gear
150
of the engine through the pinion
120
and the intermediate gear
130
. When the pinion
120
and the intermediate gear
130
rotate, the coupler
140
does not rotate because its arcuate arms
141
,
142
(shown in
FIG. 4B
) stay in the circular grooves
121
,
131
, respectively.
However, in the conventional structure, there has been a problem in assembling the intermediate gear
130
to the pinion
120
. The coupler
140
easily drops off from the circular grooves
121
,
131
in the assembling process because it is only loosely positioned in the circular grooves. Accordingly, it has been difficult to keep the coupler
140
in the position in the assembling process. Further, there has been another problem that it is difficult to give a sufficient mechanical strength to the coupler
140
because it must be positioned in thin circular grooves
121
,
131
formed on the pinion
120
and the intermediate gear
130
. Especially, it has been difficult to secure a sufficient bending strength of the coupler
140
, because the coupler
140
must be made thin to be accommodated in the circular grooves
121
,
131
.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an improved starter motor having an intermediate gear, in which a pinion and the intermediate gear is coupled with an easily mountable retainer having a sufficient mechanical strength.
A starter motor for cranking an internal combustion engine includes a pinion driven by an electrical motor and an intermediate gear engaged with the pinion. The intermediate gear engages with a ring gear of the internal combustion engine to crank up the engine. The pinion is slidably and rotatably supported on an output shaft of the motor, while the intermediate gear is slidably and rotatably supported on an intermediate shaft disposed in parallel to the output shaft. The pinion and the intermediate gear are coupled with a retainer, so that the intermediate gear is shifted in its axial direction together with the pinion when the pinion is shifted to crank up the engine.
The retainer has a first groove engaging with a pinion boss formed integrally with the pinion and a second groove positioned to partly cover an outer periphery of a cylindrical boss formed integrally with the intermediate gear. The first groove has a resilient opening, a width of which is smaller than a diameter of the pinion boss. To connect the retainer to the pinion boss, the resilient opening is forcibly opened and recovers its original position after the retainer is connected to the pinion boss. Since the retainer is connected to the pinion boss in this manner, the retainer is prevented from dropping off during a process of assembling the intermediate gear to the starter motor. The positions of the first and the second grooves of the retainer may be reversed so that the retainer engages with the cylindrical boss of the intermediate gear in place of the pinion boss. Since the retainer is positioned outside the pinion boss and the cylindrical boss of the intermediate gear, the retainer can be made thick enough to secure a sufficient mechanical strength.
The retainer coupling the pinion and the intermediate gear does not rotate, while components contacting the retainer rotate. Convex surfaces are formed on the side surfaces of the retainer contacting the rotating components to alleviate friction between the retainer and the components.
According to the present invention, the retainer having a sufficient mechanical strength can be easily mounted on the starter motor without disturbing the assembling process. Further, friction between the retainer and rotating components is effectively alleviated.
Other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiment described below with reference to the following drawings.
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patent: 5165293 (1992-11-01), Kittaka et al.
patent: 5244104 (1993-09-01), Green et al.
patent: 5271285 (1993-12-01), Silliman et al.
patent: 5277075 (1994-01-01), Sakamoto et al.
patent: 5423156 (1995-06-01), Nellessen, Jr.
patent: 5706699 (1998-01-01), Moribayashi
patent: 5731638 (1998-03-01), Niimi
patent: 5844336 (1998-12-01), Ohya et al.
patent: 5987709 (1999-11-01), Chou
patent: 6089112 (2000-07-01), Kelly et al.
patent: 6257602 (2001-07-01), Joerg et al.
patent: U-50-91643 (1975-08-01), None
Ando Shinji
Nito Kuniaki
Wakahara Yasuyuki
Bucci David A.
Denso Corporation
Posz & Bethards, PLC
Smith Julie K.
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