US2451767A

US2451767A - Combined starter and generator

Info

Publication number: US2451767A
Application number: US674546A
Authority: US
Inventors: Romeo M Nardone
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-06-05
Filing date: 1946-06-05
Publication date: 1948-10-19
Anticipated expiration: 1965-10-19

Description

0a. 19, 1948. M RD N Y 2,451,767

COMBINED STARTER AND GENERATOR Filed June 5, 1946 2 Sheets-Sheet 1 f1 'I'TORNE Y5,

Oct. 19,1948. NARDQNE 2,451,767

COMBINED STARTER AND GENERATOR Filed June 5, 1946 2 Sheets-Sheet 2 ATTOR NE Y5,

Patented Oct. '19, 1948 2,451,767 COMBINED STARTER AND GENERATOR Romeo M. Nardone, Teaneck, N. J., assignor to Joseph J.

Mascuch, Milburn, N. J.

Application June 5, 1946, Serial No. 674,546

6 Claims.

This invention relates to a, combined starter for cranking an aviation engine and a generator run by the said engine.

An object of this invention is to provide a compact starting mechanism which may be attached directly to the engine shaft.

Another object of this invention is to provide an engine starter which shall operate as a generator once the engine is running under its own power. I

A feature of this invention is its novel friction clutch mechanism which co-operate with sprags to transmit the motor torque to the engine.

Another feature of this invention is the novel drive whereby a second set of sprags enables the engine to turn the motor directly so that it may perform the function of a generator.

The invention consists of the construction, combination and arrangement of parts, as herein illustrated, described and claimed.

In the accompanying drawings, forming a part hereof, is illustrated a complete embodiment of the invention, in which drawings similar reference characters designate corresponding parts, and in which:

Figure 1 is a vertical section of a complete embodiment of the starter generator.

Figure 2 is a cross-sectional view, taken on line 22 of Figure 1.

Figure 3 is a cross-sectional view, taken on line 33 of Figure 1, looking in the direction indicated by the arrows.

Figure 4 is a view in perspective of two sprags showing their construction.

Referring to the drawings, and particularly to Figure 1, I is a cylindrical housing surrounding the electrical portion of the mechanism. One end of the housing I0 is closed by a cup-shaped end plate II to which are attached four brush box insulators l2. Brush boxes I3 and brush rests I4 are rigidly secured to the insulator blocks l2. A terminal post l5, located between two of the brush box insulators l2 projects through the end plate The commutator brushes I6 are held in position by four brush spring assemblies l1. Each brush spring I! is inserted within a rectangular opening IS in the side of the end member The end member H is centrally bored at I9 to receive a ball bearing 20 within which the right hand end of the armature shaft 2| is 1'0- tatably held. A nut 22 is attached to this end of the armature shaft 2| to retain it in place. The retaining nut 22 is prevented from becoming loosened as a result of the rotation of the armaturn is held by a stud 4|.

ture by the use of a locking washer 23. A hub 24, secured to the end member II by a screw 25, covers the said nut 22. End motion of the armature shaft 2| is prevented by an inner nut 26 which cooperates with the outer nut 22 to hold the shaft 2| firmly to the bearing 20.

Four field coils 27, connected in series parallel, are held to the pole shoes 28 which are secured to the housing Ill by means of flat head screws 29. Two terminals 30, iii, soldered to the ends of the coils are connected, one to the inner extension of the terminal post l5 and the other to a positive brush box 3.

The left hand end of the armature shaft 2| is threaded to receive a nut 32 which holds it within a ball bearing 33. The said bearing 33 is pressed into the central bore 34 of the drive housing 35 and rotatably supports the end of the shaft 2|. A quill shaft 36 is driven by the armature 2| and is pinned to it at 31.

The engine end of the quill shaft 36 is formed into a pinion 38. Said pinion is in mesh with three planetary gears 39. Each planetary gear 39 is mounted upon a ball bearing 45, which in Snap rings 42, inserted in grooves 43 on the studs 4|, prevent the gears 39 from moving axially in the direction of the armature.

Stepped washers 44 are provided on studs 4! which keep the planetary gears from drifting toward the engine end of the studs, and serve a hereinafter described purpose.

The drive end of the starter generator is enclosed in a housing 35 which is attached to the motor housing H] by screws 48. The said drive housing 35 is somewhat cup-shaped and its transverse member 49 divides the motor portion of the mechanism from the drive chamber. A tubular support member 50 having an outwardly extending flange 5| is attached to a flange 52 on the housing 35. The support member and its flange 5| serve to partially seal the open end of the drive housing 35. The inside diameter of the tubular support member is counterbored to receive two ball bearings 53, 5-5, and an oil seal 55. The bearings 53, 54 and oil seal 55 are prevented from moving laterally by a snap ring 56, inserted in a. groove in the support member 5i), and the internal shoulder 51 of the support member 50. A retainer 58 presses the oil seal 55 into contact with the shaft 59 of a spider B5. The said shaft 59 is rotatably supported by the bearings A barrel member 6| is located within the drive housing 35. Counterbores in the barrel member the clutch plates 66, 61

6! form three steps therein. The right hand step is machined to form an internal gear 62. This gear 62 is in mesh with the three planetary gears 39 at all times. The middle step 63 receives a ball bearing 64 which rotatably supports the barrel member El upon the spider 55. Since the spider 45 holds the studs M upon which the planetary gears 39 are mounted, it is possible for the gears to move while the barrel 6| remains stationary. The stepped washers M prevent the barrel bearing 64 from step of the barrel is splined at B and receives a plurality of external clutch plates 66. The clutch plates 65 are notched to engage the splines 65 of the barrel 6|. between the external discs 66. All the clutch plates are pressed together by a wavy spring 69. Spacer plates 68, 81, 82, and lock ring 10 back up this assembly. I

The inside diameters of the inner clutch plates ETserve as cam surfaces for a plurality of sprags H, best shown in Figure 2, which surround the outside diameter 12 of the tubular support plate 50. Garter springs it are slipped into lateral grooves M in the sprags H and hold them in position. A second setof sprags 15, best shown in Figure 3, is locatedbetween the inside diameter T6 of the spider 45 and a cylinder Ti which is splined to. the end of the quill shaft 36. Garter springs 18 are provided to retain these sprags in place, and the aforementioned stepped washers 5'4 hold the said springs 18.

The inside diameter of the spider 4.5 is also used to hold aball bearing 19' which supports the left hand end of the quill shaft 35. An output shaft 80, pinned within the inside diameter 16 of the spider 45 completes the construction of the starter generator. The said shaft 88 is externally splined to engage the engine shaft (not shown).

The operation of the starter generator becomes apparent from the foregoing and by reference to the drawings. When it is being used as a starter current is fed to terminal l5 which causes the armature shaft 2i to rotate and turn quill shaft 36. The pinion 38 on the quill shaft 36 thereupon turns the planetary gears 39. The torque upon the output shaft 80 would cause the barrel 6| to rotate in a direction opposite to that of the pinion, except for the action of the sprags ii and the clutch plates 65, 61. However, if-an overload occurs on the output" shaft 80, the clutch plates 66, 51 will slip and damage tothe unit will be avoided. I

The Wave spring 69 gives the clutch plates 66, 5'5 the desired amount of resistance. When the barrel 6| is held stationary by the sprags H and the spider E5 is driven at a considerable reduction in speed and with great torque. The spider 45 in turn drives the output shaft 813 which is connected to the engine shaft and rotates the. crankshaft to start the engine.

Once the engine starts and runs under its own power the unit operates as a generator. The output shaft 80 turns the spider 35 which translates its motion to the quill shaft 36 through the sprags 15 and the cylinder TI. This constitutes a direct drive from the engine to the armature. While the unit is being used as a generator the barrel 6! is forced to rotate together with the output shaft 80, and the quill shaft pinion 38.

This revolution of the barrel member 6| is possible by the over-running at the sprags ll'which rotate. together with the clutch plates t6, 5?.

Having thus fully described the invention, what Internal plates 61 are'positioned shifting. The left hand is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a combined starter and generator, an electric motor, a starter unit attached thereto and directly coupledto the engine, a gear train comprising a plurality of planetary gears rotated by the electric motor, means within the starter unit consisting of an internally geared barrel member in mesh with the said gears, and means comprising a plurality of clutch discs mounted upon sprags, said sprags being journaled upon a tubular support member within the said starter unit to prevent the said barrel from rotating, to transmit the torque from the said gear train to the engine and means to drive the electric motor from the'engine once said engine is operating under its own power.

2. In a combined starter and generator, an electric motor, a starter unit attached thereto and directly coupled to the engine, a gear train rotated by the electric motor, means within the starter unit to transmit the torque from the said gear train to the engine and means comprising an output shaft attached to a spider, said spider retaining within its bore a plurality of sprags disposed around a cylinder in such manner as to rotate the said cylinder which in turn is adapted to drive the electric motor from the engine once said engine is operating under its own power.

3. In a combined starter and generator, an electric motor, a starter unit attached thereto and directly coupled to the engine, a gear train com-- prising a plurality of planetary gears rotated by the electric motor, means within the starter unit consisting of an internally geared barrel memher in mesh with the said gears, and means comprising a plurality of clutch discs mounted upon sprags, said sprags being journaled upon a tubular support member within the said starter unit to transmit the torque from the engine and means comprising an output shaft attached to a spider, said spider retaining within its bore a plurality of sprags disposed around a cylinder in such manner as to rotatethe said cylinder which in :turn is adapted to' drive the electric motor as a generator from the engine once said engine is operating under its own'ppwer.

In a starter generator, in combination, an electric motor, a starter unit attached; thereto, a plurality of planetary gears therein, a spidersupporting said gears, an internally toothed barrel member in mesh with the planetary gears, a plurality of clutch plates tofrictionallyhold the said barrel, a plurality of sprags supporting said clutch plates, a support member upon which the said sprags. are journaled, a. wave spring to maintain pressure on the clutch platesand an engine, said engine being coupled directly to thesaid starter unit to operate the said motor as a generator.

5., In a starter generator, .in combination, an electric motor, a starter ,un-it attached thereto, a plurality of planetary gears therein, a spider supporting said gears, an internally toothed barrel member in mesh with the planetary gears, a plurality of clutch plates to frictionally hold the said barrel, a plurality of sprags supporting said clutch plates, garter springs adapted to-retai-n the said sprags in place, a support member upon which the said sprags are journaled a wave spring to maintain pressure on the clutch plates, and an engine,- said engine being coupled directly-to. the said starter unit to operate the said motor as. a generator. 7 r 3 -6. In a starter generator, in combination, an

the said gear train to ator, an output shaft in contact with the engine, a plurality of sprags retained within the bore of springs adapted to hold the the said spider, garter sprags in inder engageabl position, and an internally splined cyle by said sprags.

ROMEO M. NARDONE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Jones et al Knapp Koch Date Feb. 24, 1914 Oct. 27, 1925 June 17, 1930