Prime-mover dynamo plants – Miscellaneous – Drive gearing
Reexamination Certificate
2000-10-30
2003-03-18
Waks, Joseph (Department: 2834)
Prime-mover dynamo plants
Miscellaneous
Drive gearing
C310S153000
Reexamination Certificate
active
06534880
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a magneto generator for an internal combustion engine and more particularly to an improved and simplified manner of forming such a construction and attaching it to the crankshaft of the associated engine.
Conventionally with a wide variety of types of engines, particularly but not limited to those of the small displacement type, a projecting end of the crankshaft has attached to it a flywheel, a starter mechanism and magneto generator assembly. These mechanisms comprise a number of component parts that are connected to each other by a plurality of different types of fasteners. In addition, it is also the common practice to provide a protective coating over the permanent magnets of the magneto generator to protect them. These structures have a number of defects, which may be best understood by reference to
FIG. 1
which is a figure showing a conventional prior art type of construction.
An associated engine has a crankshaft, indicated generally by the reference numeral
11
, which protrudes through an end face of the associated crankcase in which the crankshaft
11
is journalled in a well known manner. A flywheel magneto starter assembly, indicated generally by the reference numeral
12
, is affixed to the crankshaft
11
in a manner that will be described. This flywheel magneto starter assembly
12
includes a number of components including a mounting boss member, indicated generally by the reference numeral
13
and which has a flange portion
14
that is generally cylindrical in shape. The flange portion
14
is integrally formed with a cylindrical sleeve part
15
and which has an internal bore
16
that is received over a tapered end of the crankshaft
11
. A key
17
is positioned in a key groove
18
formed in the crankshaft
11
and in a slot formed in the sleeve bore
16
so as to non-rotatably affix the mounting boss member
13
to the crankshaft
11
.
A flywheel magneto member
19
is affixed, in a manner to be described, to the mounting boss member
13
and cooperates with a stator
21
that is fixed to the engine body. The flywheel magneto assembly
12
generates electrical power for, among other things, the ignition of the associated engine.
The flywheel magneto member
19
has a generally cup-shape comprised of a cylindrical flange
22
and an end wall
23
. Carried on the inner periphery of the cylindrical portion
22
are a plurality of permanent magnets
24
that cooperate with the stator
21
so as to generate an electrical current therethrough on rotation of the flywheel magneto assembly
12
with the crankshaft
11
.
The flywheel magneto member
19
is affixed to the mounting boss member
13
by means of a plurality of rivets, indicated by the reference numeral
25
. These rivets
25
have headed portions that are disposed on one side of the end wall
23
and conical portions that are received in correspondingly machined openings
26
formed in the mounting boss member
13
. The conical portions
26
are required in order to clear a one-way clutch assembly, indicated generally by the reference numeral
27
which is associated with a starter gear
28
that is journalled on the crankshaft
11
and has teeth on its outer periphery. A starter motor is engaged with these teeth for rotating the starter gear
28
.
The one-way clutch
27
includes an inner race that is formed by a hub
29
of the starter gear
28
and which drives a plurality of sprags
31
and retainers
32
for driving an outer race
33
. The outer race
33
has tapped openings that receive threaded fasteners
34
. The threaded fasteners
34
are socket headed screws and pass through enlarged openings in the flywheel end wall
23
so as to affix the outer race
33
to the mounting boss member
13
.
Finally, spacers
35
are positioned internally of the permanent magnets
28
to space them at a fixed distance from the end wall
23
and a protective covering
36
covers the surfaces of the permanent magnets
24
so as to protect them. The protective casing
36
is made from a non-magnetic material such as stainless steel and is adhesively bonded to the permanent magnets
24
.
It should be readily apparent from the foregoing description that the prior art type construction is rather time consuming to manufacturer and assemble. The problems associated with the use of the fastening rivets
25
have already been touched upon. In addition, the use of the separate threaded fasteners for securing the hub portion
13
to the one-way clutch outer race
33
adds to the number of fasteners in the area and thus, weakens the overall assembly. The use of the relatively large number of fasteners and the associated holes through which they pass requires thickening of these members which adds weight in an area where it aids little to the flywheel effect. It would be better to have the added material on the outer periphery where the effect would be greater.
Furthermore, the adhesive bonding of the protective cover
36
to the permanent magnets
24
gives rise to not only a messy operation but also requires time for setting before the assembly can be completed and used.
It, therefore, a principal object to this invention to provide an improved flywheel magneto for an internal combustion engine.
It is a further object to this invention to provide an improved, simplified lower cost and better performing flywheel magneto that offsets the disadvantages noted.
SUMMARY OF THE INVENTION
A first feature of the invention is embodied in a flywheel rotor of a magneto generator for an internal combustion engine for rotating together with a crankshaft of the engine. The flywheel rotor comprises a mounting member having a sleeve portion adapted to be nonrotatably secured on the crankshaft and a flange portion formed integrally with the sleeve portion. The flange portion is generally in the shape of a disc. An engine starter component is disposed on one side of the flange portion and a flywheel member generally in the shape of a cup is disposed on the other side of the flange portion. A plurality of circumferentially spaced permanent magnets are affixed on the inner surface of the flywheel member. A plurality of threaded fasteners, each having portions extending axially through each of the flange portion, the engine starter component and the flywheel forming the sole connection between the mounting member, the engine starter component and the flywheel member.
Another feature of the invention is also embodied in a flywheel rotor of a magneto generator for an internal combustion engine for rotating together with a crankshaft of the engine. In accordance with this feature, the flywheel rotor also comprises a mounting member having a sleeve portion adapted to be nonrotatably secured on the crankshaft and a flange portion formed integrally with the sleeve portion. The flange portion is generally in the shape of a disc. An engine starter component is disposed on one side of the flange portion and a flywheel member generally in the shape of a cup is disposed on the other side of the flange portion. A plurality of circumferentially spaced permanent magnets are affixed on the inner surface of the flywheel member. A permanent magnet protection casing generally in the shape of a cup is received within the flywheel member in close contact with inner surfaces of the permanent magnets. A plurality of fasteners affix the engine starter component, the flywheel, the boss member and the permanent magnet protection casing to each other.
REFERENCES:
patent: 3781137 (1973-12-01), Engstrom
patent: 4137884 (1979-02-01), Odazima et al.
patent: 4218193 (1980-08-01), Mehne
patent: 4317435 (1982-03-01), Kohlhage
patent: 4433473 (1984-02-01), Benedetti
patent: 4735299 (1988-04-01), Ohuchi
patent: 4754859 (1988-07-01), Ouchi et al.
patent: 4877986 (1989-10-01), Shimizu
patent: 4918323 (1990-04-01), Aso
patent: 5495833 (1996-03-01), Ishizaka et al.
patent: 5524597 (1996-06-01), Hiki et al.
patent: 6053155 (2000-04-01), Kashima
patent: 56074098 (1982-11-01), None
patent: 2-248651 (1990-04-01), None
Sone Kazuya
Takagi Kazuyoshi
Beutler Ernest A.
Kabushiki Kaisha Moric
Waks Joseph
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