US3435265A - Housing and mounting for ignition trigger circuit - Google Patents

Description

f) F M. MINKS {March 25, 1969 Z'IOUSING AND MOUNTING FOR IGNITION TRIGGER CJTR CIJI'I Sheet Z 01"? Filed an. 5, 1967 INVENTOR 20m M BY Afforne F. M. MINKS March 25, 1969 HOUSING AND MOUNTING FOR IGNITION TRIGGER CIRCUIT Sheet Filed Jan.

INVENTOR flora M Mums Bwcxmc OSCILLATER CHARGING CIRCUIT Patented Mar. 25, 1969 3,435,265 HOUSING AND MOUNTING FOR IGNITION 'I'RIGGER CIRCUIT Floyd M. Minks, Kissimmee, Fla., assignor, by mesne assignments, to Brunswick Corporation, Chicago, 111., a corporation of Delaware Filed Jan. 3, 1967, Ser. No. 606,609 Int. 'Cl. H02k 11/00 US. Cl. 310-70 13 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a breaker-less ignition system for an automobile. The distributor has a vane that includes a plurality of circumferentially distributed apertures that control the pulse forming trigger circuit for the spark plugs.

This invention relates to a trigger circuit for a breakerless semi conductor ignition system and particularly to the mounting of the trigger as a part of the distributor of an internal-combustion engine.

Capacitor discharge ignition systems for internal-combustion engines and the like have recently been suggested wherein a capacitor is alternately charged from a battery and/ or the generator system and rapidly discharged through an induction transformer to fire the spark plugs. A highly satisfactory switching means for controlling the charging and discharging of the capacitor is a silicon controlled rectifier or the like. As disclosed in applicants copending application entitled, Pulse Forming Circuit and Capacitor Discharge Ignition Systems Therewith, filed on Nov. 3, 1966, Ser. No. 591,835 and assigned to the same assignee herewith, a highly satisfactory means for triggering of the various elements of the charging and the discharging circuit employs a vane controlled oscillator as a part of a trigger or pulse forming circuit. The vane control oscillator includes a rotating vane to couple and decouple the windings of the oscillator and to thereby turn on and off a trigger means. The system avoids the usual contacts employed in conventional and ignition systems and provides a very reliable firing means over long periods of operation.

The present invention is particularly directed to the structure for mounting and housing such a vane controlled pulse forming system and to a special construction of the several components forming a part of such a system.

Generally, in accordance with the present invention, a rotating vane is secured to the distributor shaft and includes alternately conductive and nonconductive portions. The several circuit components are potted within a generally horseshoe unitwhich is releasably secured within the housing of a distributor. The housing includes a small support member secured to one edge and projecting inwardly to define a gap through which the vane passes. The windings of the oscillator are disposed to the opposite sides of the gap within the basic housing and the support member. The U-shaped construction permits mounting about the distributor drive shaft which is connected to the internal-combustion engine without removal or disassembly of the vane support constructon. This system also permits complete potting and encapsulation of all of the components while maintaining economical method of manufacturing.

The windings of the oscillator circuit which include the winding in the output circuit and the feedback winding connected in the input circuit are specially wound on similarly formed ferrite cores having a central cylindrical portion terminating in enlarged rectangular end portions. They are mounted within the housing and potted therein to provide physical support for the components while providing close spacing therebetween. The rotating apertured vane passes therebetween to alternately align the conductive and nonconductive portions therewith.

It has been found that the present invention provides a highly unusual and reliable means particularly adapted for ignition systems employed in outboard motors and the like.

The drawings furnished herewith illustrate a preferred construction of the present invention in which the above advantages and features as well as others will be clear from the following description.

In the drawings:

FIG. 1 is a partial elevational view of an outboard motor with parts broken away to show an engine and distributor;

FIG. 2 is an enlarged vertical section through a distributor such as shown in FIG. 1 and constructed in accordance with the present invention:

FIG. 3 is a view taken generally on line 33 of FIG. 2;

FIG. 4 is a section taken on line 44 of FIG. 3;

FIG. 5 is a pictorial view showing one winding unit. of an oscillator;

FIG. 6 is a fragmentary view showing certain components of the oscillator in a separated arrangement to show details of construction; and

FIG. 7 is a schematic circuit diagram of a preferred oscillator circuit, the components of which may be mounted in accordance with the showings of FIGS. 25.

Referring to the drawings, and particularly to FIG. 1, a portion of an outboard motor is shown including an internal-combustion engine I mounted to the upper end of the lower drive shaft unit 2. The lower end, not shown, of the drive shaft housing 2 carries the propeller, not shown, which is coupled to the engine 1 through a suitable drive shaft mechanism in accordance with any known or desired construction. A protective and decorative cowling 3 is provided encircling the upper portion of the engine 1.

The engine 1 is the usual internal-combustion engine having a plurality of spark plugs 4 for sequentially firing of the various cylinders and a distributor 5 mounted to the engine and coupled through a flywheel assembly 6 to be driven in synchronism with the engine. The distributor 5 is connected by a lead 7 to the output of a transformer 8, shown only in FIG. 7, and by a plurality of leads 9 to the several spark plugs 4 for sequential firing thereof.

Referring particularly to FIG. 2 an enlarged sectional view of the lower portion of the distributor 5 is shown constructed in accordance with the present invention. Generally, the distributor includes a drive shaft housing assembly 10 which is supported on the engine block and to which is secured a trigger pulse forming assembly 11 and a high voltage distributing assembly 12.

The housing assembly 10 includes an inner housing 13 through which a shaft 14 extends and is suitably connected to be driven at its upper end from the assembly 6 by a drive chain or the like, not shown. The shaft 14 terminates within the lower end of the housing 13 and is connected to a distributor shaft 15 by contact between protruding sections 16 on the shafts.

The lower end of housing 13 is formed as an inverted annular U-shaped mounting flange having inner and outer walls 17 and 18. A bearing housing 19 is mounted within the inner wall 17 and includes a pair of axially spaced ball bearings 20 and 21 to which the distributor shaft 15 is secured. The bearing housing 19 includes an annular flange 22 extending outwardly beyond the outer edge of the outer wall 18 of the drive shaft housing and a pair of attachment screws 23 attach it to the trigger assembly 11 which in turn is secured to the outerwall 18 by a plurality of clamping screws 24.

The trigger assembly 11 includes a horseshoe-shaped housing 25 formed of a cast aluminum or other suitable material and secured in place by the plurality of clamping screws 24 which extend through appropriate aligned openinlgs in the outer wall 18 of the drive shaft housing and the bearing flange 22 and thread into appropriately tapped openings in the trigger housing.

An outer distributor cap 26 of high voltage distributing assembly 12 and an annular adaptor member 27 are secured in stacked relation to the outermost peripherey of the bearing flange 22. The adaptor member 27 is ringshaped and encircles the trigger housing 25. A pair of attachment nut and bolt assemblies 28 passes through the member 27 and the bearing flange 22. The cap 26 is a cup-shaped member having its periphery edge mating with the outer edge of the adaptor member 27. A pluraliay of nut and bolt assemblies 30 passes through appropriate openings in the cap 26, the adaptor member 27 and the flange 22 to releasably interlock the cap in place. Appropriate gaskets 31 and 32 are provided between the outer faces to the opposite peripheral end edges of the adaptor and the adjacent surfaces to provide a fluid tight type joint.

The distributor cap 26 includes a plurality of outer circumferentially distributed towers 33 within which terminals 34 are provided to receive the leads 9 from the several spark plugs 4. The distributor cap 2.6 also includes a central terminal 35 having a threaded outer portion 36 to receive lead 7 from the transformer 8 and an inner portion 37 projecting into the cap 26.

The distributor shaft extends through the trigger assembly 11 and into the cap 26. A plastic rotor 38 is secured to the lowermost end of the shaft. Thus, in the illustrated embodiment of the invention, the lower end of the shaft is provided with a knurled, reduced portion 39 to which the plastic cap 38 is cast to provide a firm and strong physical connection therebetween. A high tension contact plate 40 is embedded within the rotor 38 and projects horizontally outwardly from the central portion beyond the outer periphery of the rotor and sequentially moves past the spark plug terminals 34 which are imbedded within the towers in the cap 26.

The contact plate 40 is connected to the high tension lead by the threaded terminals 36 and particular portion 37 which projects inwardly to the inner portion of plate 40 in the assembled relation of the cap 26 to the housing assembly.

The distributor shaft 15 is further formed with a central stepped portion including a flange 41 immediately adjacent an enlarged portion 42. A thin metal disc 43 forming a control vane is assembled on the enlarged portion 42 and abutting the flange 41. It is fixed thereto by a pressfitted clamping ring 44 which is forced over the enlarged portion 42 into abutting engagement with the opposite face of the disc 43. The assembly is arranged and constructed to dispose the vane in closely spaced relation to the outer face of the trigger housing.

The disc or vane 43 includes a plurality of circumferentially distributed apertures or slots 45 one for each of the spark plugs 4 and forms an operating part of the trigger assembly to provide a breaker-less ignition system.

Before describing the structural details of the trigger assembly, a highly satisfactory trigger circuit is shown in FIG. 7 and is briefly described to clearly relate the structural arrangement of FIGS. 1-6.

lRefering particularly to FIG. 7, the illutrated ignition system is of a capacitor discharge system similar to that disclosed in applicants previously referred to copending application. Consequently, it is only briefly described here- Generally, it includes a main capacitor connected to a blocking oscillator 47 to be charged to a preselected level. The capacitor 46 is connected in an output circuit with a silicon controlled rectifier 48 and the output transformer 8 which in turn is connected to the high tension terminal 36 of the distributor 5 by lead 7. By alternatively charging of the capacitor 46 and firing the silicon controlled rectifier 48 to discharge the capacitor, in timed relation to the movement of the rotor 38, high voltage firing pulses are applied to the several spark plugs 4 in appropriate sequence. The pulse to fire the silicon controlled rectifier 48 as well as to initiate a cycle of the blocking oscillator 47 is obtained from the trigger assembly 11 which is housed within housing 25, as presently described.

Generally, the illustrated trigger assembly includes a trigger capacitor 49 connected to the battery 50 or other D.C. source forming a part of the internalcombustion engine through a voltage dividing network 51 and to the gate of the silicon controlled rectifier 48 as well as to the trigger elements of the blocking oscillator 47, not shown, by a switching transistor 52. The capacitor 49 is charged from the battery 50. A triggered oscillator 53 operating in the current mode is connected across a portion of the voltage dividing network 51 and the capacitor 49 and functions as a selectively triggered switch means. The triggered oscillators 53 in turn is controlled by a gated oscillator 54 including an output winding 55 and a feedback winding 56 selectively coupled and decoupled by the rotating vane disc 43.

When the aperture 45 is aligned with the magnetic circuit of the windings 55 and 56, the windings are coupled to form a free-running oscillator which begins to oscillate. However, when the continuous portion of the disc 43 is aligned with the magnetic circuit, the windings are decoupled and the circuit will not oscillate. Therefore, each alignment of an aperture 45 with the magnetic circuit of the windings provides an output signal which triggers the triggered oscillator 53 and, as more fully described in the previously referred to copending application, provides a discharge path for the capacitor 49. The oscillator 53 includes a coupling transformer having a winding 57 in the discharge path and a winding 58 in the feedback path to derive sustaining power from the capacitor 49 and also provides a turn-on bias to the transistor 52. The energy of the capacitor 49 is primarily discharged through the low resistance path of transistor 52 to turn on the blockingtoscillator 47 and the silicon controlled rectifier 48.

In the illustrated embodiment of the invention shown in FIGS. 2-6, each of the windings 55 and 56 is similarly wound on a separate similar core, most clearly shown in FIG. 5. Generally, the core is an integral member having a central winding rod 58 terminating at its opposite ends in enlarged rectangularly shaped blocks 59 and 60. The winding 55 is wound on the cylindrical rod 58 between the two blocks 59 and 60 with the winding lying completely within the outer projected surfaces of the blocks.

The trigger housing 25 is generally a horseshoe-shaped member having a horseshoe cavity 61 opening from a principal face. The base of the cavity 61 is stepped to define a supporting ledge 62 for a plastic horseshoe-shaped supporting plate 63 upon which the several components of the trigger assembly shown in FIG. 7 are mounted. The one end of the horseshoe cavity is provided with a recess through which the connecting leads 64 are secured with a suitable insulating grommet 65.

As most clearly shown in FIG. 6, the opposite end of cavity 61 terminates in spaced relation to the end wall of housing 25 and a small rectangular cavity 66, substantially corresponding to the outer configuration of the winding unit shown in FIG. 5, is provided to receive the one prewound unit. The prewound unit is secured within the small cavity 66 by a suitable epoxy or other sealing and supporting material 67, as most clearly shown in FIG. 4. The cavity 66 and particularly the end blocks 59 and 60 are arranged on a radius of the disc 43 such that the radial apertures or slots 45 are sequentially disposed in overlying relationship with respect to the winding and the associated core.

A small rectangular support plate 68 includes an outer mounting lip 69 secured to housing 25 and a main support body 70 which projects inwardly over the disc 43 and cavity 61. A cavity 71 corresponding to cavity 61 is formed on the inner surface of the body 70 in accurate alignment with the first cavity 66. The second winding unit, similar to FIG. 5 is disposed Within the outer cavity 71 and thus is aligned with the first winding. The unit is held within the cavity 71 by a suitable potting material 72. The rotating vane 43 moves between the two core units and alternately provides a conductive and nonconductive portion therebetween. When the conducting portion of the disc 43 is interposed between the two cores it provides a short circuit condition establishing an opposing flux to that established by energization of the one Winding and thereby prevents coupling therebetween. When the aperture 45 is aligned therewith, the flux can readily move therebetween to provide a desired coupling and oscillatory operation of the circuit. If the portion of either or both housings encircling the cores is a metal, eddy current shielding is provided. a

The leads 72 for the outer Winding extend through small aligned recesses in the cap body 70 and housing 25 into cavity 61 for interconnection into the circuit, as shown in FIG. 7.

Further, after assembly of the circuit board 63 to the housing 25 and the support body 70 to the housing, the cavity 61 is filled with an epoxy or other suitable material 73 to completely encapsulate the assembly. This not only protects the components from adverse surroundings but physically supports the components and the several connections.

In the assembly of the distributor components, the bearing unit and shaft are interconnected. The trigger housing 25 with the several circuit components potted therein is installed with the housing rotated slightly to move the vane Within the gap between the housing 25 and the adjacent support. The subassembly is connected to the drive shaft housing 13 by the attachment screws 24. The adaptor 27 is secured to the flange 22 by the nut and bolt assembly 28 and the cap 26 secured to the flange 22 by the nut and bolt assemblies 30 to complete the distributor.

If repairs are ever necessary the trigger housing can be readily assemblied without disruption or movement of the rotating vane. The vane is thus locked in place with respect to the distributor rotor 38 and contact plate 40 to maintain precise actuation of the trigger assembly with respect to the connection of the transformer 8 to the several spark plugs 4.

The mounting of the vane and the separate housing of the trigger has been found to provide a very reliable and long life breaker-less ignition system for internal-combustion engines and particularly suitable for outboard marine operation. If desired certain of the internal components could be separately mounted in any desired manner and further a completely potted type arrangement could be employed.

It has been found however that the illustrated embodiment of the invention provides a very satisfactory and reliable unit for outboard motors and the like.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. A distributor comprising:

a support member,

a shaft rotatably journaled in the support member,

said support member including a housing with the shaft passing adjacent the housing,

a plurality of electrical elements within said housing,

a support member disposed in spaced relation to the housing and defining a control gap therebetween,

a first winding secured within the second named support member,

a second winding secured within the housing in alignment with said first winding,

said elements and windings forming at least a part of a pulse forming circuit with said windings connected to control the output of the pulse forming circuit in accordance with the coupling of the windings, and

a member secured to the shaft in spaced relation to the support member in alignment with said gap and having alternate portions to vary the coupling of said windings.

2. The distributor of claim 1 wherein said housing is a generally horseshoe-shaped housing having the shaft passing through the center thereof.

3. The distributor of claim 1 having a pair of magnetic cores each including a central rod portion and outer enlarged end portions, said windings being wound one each on the central rod portions of the cores, and said cores being mounted within the housing and support member with the cores in alignment.

4. The distributor of claim 3 wherein said enlarged end portions are block-shaped and are mounted with the outer faces parallel to each other and to the member, said member being a disc.

5. The distributor of claim 4 wherein said disc includes alternate conductive and nonconductive portions and each of said cores is encircled by a conductive member on all sides not facing the disc.

6. The distributor of claim 4 wherein said disc is a thin metal member having a series of circumferentially spaced radial apertures, and said cores are disposed in metallic members having cavities substantially corresponding to the configuration of said cores.

7. The distributor of claim 1 wherein said housing includes a body portion having a cavity therein opening toward the member, said elements being mounted and interconnected within said cavity, a potting material filling said cavity, a small cavity in said body portion, said second Winding being secured in hte small cavity, said second named support member being a plate including an inner cavity aligned with said small cavity, and said first winding being disposed within said inner cavity.

8. The distributor of claim 7 having a pair of magnetic cores, each including a central rod portion and outer enlarged end portions, said small and inner cavities being formed to conform to the outer dimensions of the enlarged ends, and a potting compound within said cavities securing the cores and windings therein.

9. The distributor of claim 1 wherein said first support member includes a central bearing hub and a support flange, bearing means secured Within the hub and to said shaft to rotatably support said shaft, said housing being secured to said flange, said shaft being formed with a flange aligned with said gap and an enlarged portion immediately adjacent said flange, said member secured to the shaft being a disc member having a central opening and being disposed over the enlarged portion in abutting engagement with the flange, a clamp ring secured over the enlarged portion to fix said disc member to said shaft, a rotor secured to the end of the shaft and having a common contact arranged in selected angular orientation with respect 0t said alternate portions of said disc member, and a disributor cap mounted in fixed overlying relation to said rotor and having fixed contacts whereby said windings are coupled to produce an output pulse Whenever said common contact is aligned with a fixed contact.

10. A subassembly forming a part of a breaker-less ignition system for forming firing pulses in response to a rotating disc member in a distributor having alternate portions adapted to control the coupling of aligned windings disposed to oposite sides thereof, comprising:

a horseshoe-shaped housing,

a winding mounted within the horseshoe-shaped housing and disposed in alignment with the alternate portions of said disc member, and

electrical components secured to said housing and connected in circuit with said winding to form at least a part of a pulse forming circuit.

11. The distributor subassembly of claim 10 having a support member secured to the outer edge of the horseshoe-shaped housing and projecting thereover to define a gap therebetween greater than the thickness of said disc member, and a winding mounted within said support member in alignment with said first winding, the coupling of said windings being responsive to the alternate portions of said disc member.

12. The distributor subassernbly of claim 10 having a magnetic core for said winding including a central rodlike portion and enlarged end blocks, said winding being wound on the rod-like portion and said core having an outer surface parallel to the rotating disc member.

13. The distributor of claim 1 wherein the member secured to the shaft is nonmagnetic.

References Cited UNITED STATES PATENTS 2,792,821 5/1957 Kiekhaefer 310-70 3,254,247 5/1966 Falge 20019 3,258,551 6/ 1966 Sawyer 200-19 3,328,614 6/1967 Falge 310-70 3,370,190 2/1968 Neapolitakis 310-70 3,375,812 4/1968 Koda 200-19 J D MILLER, Primary Examiner.

US. Cl. X.R.

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