US2230008A

US2230008A - Magnetogenerator

Info

Publication number: US2230008A
Application number: US192781A
Authority: US
Inventors: Edward B Nowosielski
Original assignee: Bendix Aviation Corp
Current assignee: Bendix Aviation Corp
Priority date: 1938-02-26
Filing date: 1938-02-26
Publication date: 1941-01-28
Anticipated expiration: 1958-01-28

Description

1941 E. B. NOWOSIELSKI 0 MAGNETOGENERATOR Filed Feb. 26. 1938 3 Sheets-Sheet 1 ATTORNEY 1941- E. B. NOWOSIELSKI MAGNETOGENERATOR Filed Feb. 26.. 1938 3 Sheets-Sheet 2 Bil/W ATTORNEY Jan. 28, 1941. 0

ATTORNEY Patented Jan. 28, 1941 UNITED STATES.

PATENT OFFICE 2,230,008 MAGNETOGENERATOB Application February 26, 1938, Serial No. 192,781

2 Claims.

The present invention relates to a magnetogenerator and more particularly to a high tension generator adapted to furnish ignition current for internal combustion engines.

It is an object of the present invention to provide a magnetogenerator which is eflicient and reliable in operation, simple in construction and easily assembled and adjusted.

It is another object of the invention to provide a magneto that is to be utilized with a two cylinder opposed firing internal combustion enime.

A further object of the invention is to provide a magneto that supplies two high tension sparks simultaneously. a

A still further object of the invention is to provide a simultaneous firing magneto that utilizes two separate ignition coils.

Another object of the invention is to provide a double firing magneto having only a single condenser and a single breaker mechanism.

It is another object of the invention to provide a magneto which is incorporated with the internal combustion engine to be ignited and having the rotor of the magneto mounted directly on the shaft of the engine.

A further object of the invention is to provide a magneto in which the induction coils and cores are detachably mounted on the frame of the magneto.

A still further object of the present invention is to provide a flywheel magneto in which the flywheel is readily removable.

The above and further objects and novel features of the invention will more fully appear from the following detailed description taken in connection with the accompanying drawings. One embodiment of the invention has been illustrated in the accompanying drawings, but it is to be expressly understood that the said drawings are for purposes of illustration only and are not to be construed as a definition of the limits of the invention, reference being had primarily to the appended claims for this purpose.

Fig. 1 is substantially a midsectional view through the axis of a magneto illustrating a preferred embodiment of the present invention.

Fig. 2 is a plan view showing the structure of of the stator and one embodiment of the rotor.

Fig. 3 is a plan view showing the structure of the stator and another embodiment of the rotor.

Fig. 4 is a sectional view taken substantially on line 4-4 of Fig. 3.

Fig. 5 is a top plan view of the magneto with the flywheel removed.

Referring first to Fig. 1 of the drawings, there is illustrated a magnetogenerator comprising a casing i of generally cylindrical shape adapted to be received on the casing of the engine 2 for which the generator is adapted to supply the ig- 6 nition current. A rotor generally indicated at 3 is rotatably mounted within casing I and is mounted on a shaft 4 which may be the shaft of the engine or a stub shaft coupled therewith. A flywheel hub member 5 in the form of a cupped l0 disc having an extended hub 6 is suitably keyed on the end of shaft 4 and is formed at its periphery with a shoulder 1 arranged to substantially enclose the breaker mechanism}.

Permanent magnets in the form of arcuate l5 bars H are arranged in pairs as indicated in Fig. 2 on opposite sides of the axis of the rotor and are arranged to interflt between pole pieces l2 and I3 of suitable magnetic material. Pole pieces l2 and I3 are of unequal angular length for the reasons to be hereinafter more fully explained and are retained in assembled relation with arou- -ate magnets II by means of plates [4 and I5 of suitable non-magnetic material. Suitable rivet means ll are employed to hold the rotor in assembled relation. Plate l4 has a shoulder l6 which abuts against plate I5 and. also is adapted to be placed upon shaft 4 and is held non-rotatably on said shaft by a suitable key means 20. Rotor 3 is held in a locked position on shaft 4 by means of lock nut 18. Tapped holes l9 are placed in shoulder ii of plate l4 to facilitate the withdrawal of rotor 3 from shaft 4 by means of a suitable tool. a

In the embodiment illustrated in Fig. 3 the magnetic circuit of the rotor is strengthened since the length of the arcuate magnets II is longer.

As illustrated in Figs. 2 and 3 the inductor circuit is rectangular with laminated inductor ele ments 2| and 22 having

poles

23 and 24 unsymmetrically arranged so that the distance between the poles is greater at one end than it is at the other end. The purpose of this will be set forth more fully hereinafter.

Parallel end cores

25 and 26 are detachably mounted on laminations 2| and 22, and adapted to be mounted thereon are

ignition coils

21 and 28 shown in Figs. 1 and 3. Clamps 29 securably attach

coils

21 and 28 with so their

respective cores

25 and 26 to inductor elements 2| and 22.

Laminations

23 and 24 are rigidly held together by means of rivets 3| passing through the lami nations and being anchored to the top plate 5 acts as the cam for operating breaker mechanism 8. The cam and flywheel may be removed from shaft 4 very readily simply by loosening nut 31 which will pull the cam and flywheel 01f shaft 4.

The electrical circuit of the magneto is such that the two primary windings of

ignition coils

28 and 21 are connected in series with the wire 38 connecting the two primary windings. One end of each of the secondary windings is grounded while the other end of each winding isvconnected to one of terminals 4| and 42, to which are connected the ignition cables such as 43 leading to the spark plugs of the engine.

In the operation of the structure it will be noted that the rotation of the rotor 3 will cause rotor pole shoes I2 and I3 to be presented alternately to

stator poles

24 and 23 during each revolution of the rotor so that there will be two reversals of flux for each revolution. When this magneto is used for the ignition of a two cycle twin cylinder engine, the cam 6 and breaker mechanism 8 are so arranged that the primary circuit of the induction coils will be closed during one of the reversals of flux up to the time when the stored primary energy is at its maximum. The breaker mechanism is then opened by the cam, thus allowing a rapid change of flux in the primaries of the coils and thereby generating a high voltage in each secondary of the coils to be used for ignition purposes in the usual manner.

According to the present invention, means are provided for quenching the second reversal of flux so that it will not produce a significant amount of voltage in the secondary of the coils. Referring to Fig. 1, it will be seen that this is accomplished by spacing the magnets I I- of the rotor 3 at less than 180 degrees from each other so that the rotor pole shoe I3 subtends an arc considerably greater than the pole shoe I2. The

stator pole shoes

23 and 24 are also arranged in substantially the same angular relationship to each other as the magnets II whereby in the position illustrated and with the rotor turning in the direction of the arrow a, rotor pole shoe I3 is moved out of cooperative relation with stator pole shoe 24 and into such relation with the stator pole shoe 23 at the same time that the rotor pole shoe I2 is being transferred from stator pole shoe 23 to stator pole shoe 24. A rapid reversal of flux through the external magnetic circuit is thus secured, and it is this rever sal which is utilized to generate the ignition voltage in the

induction coils

21 and 28. When,

however, the rotor has turned through substantially 180 degrees from its position shown in Fig. 1 the reversal of flux will be comparatively gradual since the long rotor pole shoe I3 continues to bridge the short lower gap between

stator pole shoes

23 and 24 for a considerable length of time. after the rotorpole shoe I-2 has left the stator pole shoe 24.

Cam 6 is preferably formed as illustrated to maintain the breaker 8 open until after the unused reversal of flux has taken place. This, however, has been found not to be strictly necessary since with the rotor and stator constructed as herein disclosed, the unused reversal oi. fluxis so gradual that it is substantially inefiecti've to produce undesired impulses in the coil at any normal operating speeds of the device.

Although only two embodiments of the invention are illustrated and described, it is to be expressly understood that the same is not limited thereto but that various changes may be made in the design and arrangement of parts illustrated without departing from the spirit and scope of the invention as will now be apparent to those skilled in the art. Reference will be primarily had to the appended nition of the limits of the invention.

What is claimed is:

1. In a high tension magneto, a two pole magnetic rotor having pole shoes of unequal circumferential extent, a stator. comprising two pole shoes which are so spaced circumferentially of the-rotor that in one position of the latter said stator pole shoes bridge the spaces between said rotor pole shoes and two ignition coils having primary and secondary windings wound on metallic cores which join adjacent ends of said stator pole shoes on opposite sides of said rotor, the primary windings of said coils being connected in series and the secondary windings thereof being independent of each other, and a single circuit breaker mechanism for periodically interrupting the circuit containing said primary windings.

2. In a high tension magneto, a two pole magnetic rotor having pole shoes of unequal circumferential extent, a stator comprising a pair of pole pieces having pole shoes of substantially equal angular extent and separated circumferentially of the rotor by unequal spaces which correspond approximately to the angular extent of said unequal rotor pole shoes, the latter being adapted to bridge said spaces when the rotor is in one angular position, metallic cores joining adjacent ends of said pole pieces on opp site sides of said rotor and an ignition coil on each of said cores having primary and secondary windings, the primary windings of said coils being connected'in series and the secondary windings thereof being independent of each other, and a single circuit breaker means for interrupting the circuit containing said primary windings.

EDWARD B. NOWOSIELSKI.

25 claims for a defi-