Machine element or mechanism – Engine starters – Automatic
Reexamination Certificate
1999-12-15
2001-08-07
Herrmann, Allan D. (Department: 3682)
Machine element or mechanism
Engine starters
Automatic
C074S00700R, C074S00700R, C029S596000, C335S131000
Reexamination Certificate
active
06269706
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a starter for starting an engine.
2. Description of the Prior Art
FIG. 9
is a sectional view showing one example of a conventional starter disclosed in Japanese laid-Open Patent Application (Kokai) No. Hei 10-159692.
In
FIG. 9
,
1
A is an output shaft. Coaxially arranged on this output shaft
1
A are an electromagnet
2
A, an overrunning clutch
30
A provided with a pinion
30
P adapted to engage with a ring gear
50
A, a plunger
40
A consisting of an inner plunger
4
A and an outer plunger
4
B, etc. A starter with this structure is generally called a coaxial type starter.
Reference numeral
12
A is an armature of a DC motor and
16
A is a shaft (a motor shaft). Numeral
18
A is a deceleration mechanism for decelerating the torque of the shaft
16
A and transmitting it to the output shaft
1
A.
8
A is a contact shaft which is supported by an internal gear member
17
A of the deceleration mechanism
18
A substantially parallel with the plunger
40
A through a supporting hole
17
m.
100
is a front bracket,
130
is a yoke,
400
is a rear bracket, and
800
is a shift plate which connects the outer plunger
4
B to the contact shaft
8
A.
The upper side from the central axis in
FIG. 9
shows the state of a starter not in operation and the lower side from the central axis in
FIG. 9
shows the state where the starter is in operation with an electromagnet turned ON and the pinion engages the ring gear.
In this starter, when an ignition switch is turned ON and an electric current flows to an exciting coil of the electromagnet
2
A, the outer plunger
4
B is attracted by an exciting core
2
C of the electromagnet
2
A. This conventional starter has such a structure that the outer plunger
4
B is directly connected to the contact shaft
8
A through the shift plate
800
and the contact shaft
8
A also moves at the same time when the outer plunger
4
B is attracted and moved by the exciting coil
2
B. A coil spring
401
is disposed between the outer plunger
4
B and the inner plunger
4
A through a spring bearing member
401
S. The inner plunger
4
A is kept in the resting state because the coil spring
401
bends at the initial stage even when the outer plunger
4
B starts the movement by attraction. Disposed in front of the inner plunger
4
A through a shifter member
402
is an inner clutch
30
B, which is also kept in the resting state while the inner plunger
4
A is kept in the resting state. After a short interval when the outer plunger
4
B starts the movement by attraction, a moving contact
80
A mounted on the contact shaft
8
A comes into contact with a stationary contact
80
B disposed in a contact chamber ZA. When the moving contact
80
A contacts with the stationary contact
80
B, electric power is supplied from an external power source through a contact bolt
11
A to start rotation of the armature
12
A. When the output shaft
1
A starts to turn through the deceleration mechanism
18
A, the pinion
30
P starts to move toward the ring gear
50
A by the thrust generated in a helical spline portion
1
B. Then, the crest and root of the pinion
30
P agree and engage with those of the ring gear
50
A. Thereafter, when the engine starts, the output shaft
1
A is separated from the pinion
30
P by the action of the overrunning clutch
30
A and the pinion
30
p runs idle. When the power supply to the exciting coil
2
B is stopped, the pinion
30
P is disengaged from the ring gear
50
A by return springs
403
,
404
.
Further, the conventional electromagnet is assembled as shown in Japanese Laid-Open patent Application (Kokai) No. Hei 10-159692 etc. This is explained by taking the conventional starter as shown in
FIG. 9
for instance. When the electromagnet
2
A is mounted on the front bracket
100
, a switch case
2
k
enclosing the exciting coil
2
B is press-fitted direct or through another member such as rubber and resin to an electromagnet housing portion
110
of the front bracket
100
.
As described above, the conventional electromagnet
2
A of the starter is press-fitted to the electromagnet-housing portion
110
of the front bracket
1005
and assembled to control the radial movement, but since no axial control is provided, there is the possibility that the electromagnet
2
A is caused to axially move by some vibration etc. and as a result, it gets out of the normal position (the switch-housing portion
110
).
To prevent this problem, when the electromagnet
2
A is mounted on the front bracket
100
according to a method as shown in
FIGS. 10 and 11
, the switch case
2
K enclosing the exciting coil
2
B is first inserted into the electromagnet housing portion
110
. It is then fixed by crimping the open end G (the side of the deceleration mechanism
18
A) of the front bracket
100
as shown by a mark F. According to this method, it is possible to prevent the electromagnet
2
A from axially getting out of the normal position (the switch-housing portion
110
) by crimping the open end G of the front bracket
100
. However, in this case, there is added a process of crimping, and manufacturing costs are higher.
Also, when the inner components are assembled in the conventional starter as shown in
FIG. 10
, the overrunning switch
30
A and a shaft section
1
AK of the output shaft
1
A on which the sliding surface (a helical spline) for the overrunning switch
30
A is formed are first installed in the front bracket
100
. Then, the electromagnet
2
A is inserted into the switch-housing portion
110
of the front bracket
100
and secured in place by crimping. After this, it was necessary for a group of components pre-installing the plunger
4
a,
the deceleration mechanism
18
A including a flange section
1
AF of the output shaft
1
A, and a contact chamber ZA including the contact shaft
8
A to be assembled as a unit (The starter of
FIG. 9
is also assembled in the same manner as this).
Namely, in this case, it is necessary to use the shaft section
1
AK and the flange section which are separated in advance for the output shaft
1
A (Namely, as shown in
FIG. 6
, once the output shaft integrally provided with a shaft section and a flange section is assembled first, it is impossible to coaxially mount the overrunning clutch
30
A, the electromagnet
2
A, the plunger
4
a
, etc. on the output shaft
1
A).
In this case, when the output shaft
1
A is formed by combining the shaft section
1
AK with the flange section
2
AF, press fitting or crimping is the only way to combine them each other. Since this causes the eccentricity of the shaft by deformation, it is difficult to secure the accuracy of squareness etc. of the shaft portion lAK and the flange portion
1
AF. There is also a problem that the accuracy around the output shaft of the starter cannot be secured.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to solve such problems as mentioned above and to provide a starter which does not require any extra process (a crimping process) and can reduce manufacturing costs as well.
It is another object to provide a starter in which the precision around an output shaft is fully secured and further provide a manufacturing method of the starter which can realize the objects as described above.
According to the present invention, a starter is provided in which an electromagnet is axially held in position between a center bracket and a front bracket which serve as an enclosing member for the starter.
Also, a starter installation method according to the present invention comprises the steps of:
(1) mounting an output shaft integrally formed with the shaft section and the flange section on a motor through a deceleration mechanism which is combined with the flange section;
(2) coaxially mounting a plunger on the output shaft;
(3) mounting a center bracket with an electromagnet built-in;
(4) spline-connecting an overrunning clutch to the output shaft;
(5) fitting a front bracket into a center bracket in such a condition
where the electromagnet is held between the
Kamei Koichiro
Katayama Hidekazu
Kuragaki Akira
Shiroyama Shigeru
Herrmann Allan D.
Mitsubishi Denki & Kabushiki Kaisha
Sughrue Mion Zinn Macpeak & Seas, PLLC
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