US2547709A - Motor-generator gearing - Google Patents

Description

E. P. LARSH April 3, 1951 -GENERATOR GEARI NG MOTOR Filed Sept. 24, 1945 4 Sheets-Sheet 2 m w l V. W

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Aprifi 3, 1951 E. P. LARSH MOTOR-GENERATOR GEARING 4 sheaths-Sheet 3 Filed Sept. 24, 1945 INVENTOR.

April 3, 1951 E. P. LARSH 2,547,709

MOTOR-GENERATOR GEARING Filed Sept. 24, 1945 4 Sheets-Sheet 4 W agNVgTOR.

Patented Apr. 3, 1951 UNITED STATES PATENT OFFICE 2,547,709 MOTOR-GENERATOR GEARIN G Everett P. Larsh, Dayton, Ohio Application September 24, 1945, Serial No. 618,221

This invention relates to an electrodynamic device and more dynamic device that may be used either as a motor or as a generator.

It is well known in electrical theory that a dynamo or generator may be used as a motor and vice versa. However, for some purposes it has not been considered feasible to use one unit both as a generator and as a motor, in spite of the fact that the two may not be used simultaneously. An illustration of this is the generator and starter motor used in starting an internal combustion engine, whether the engine be a low compression engine or a high compression engine. In the automobile industry a generator separate and distinct from the starter is generally used. This applies to larger types of engines, as for example, Diesel engines. The use of a gener ator separate from the starter motor obviously increases the cost of production, adds weight and also multiplies the parts that may get out of order and require repairs.

, An object of this invention is to provide an electrodynamic device that functions as a motor when starting an internal combustion engine and functions as a generator after the engine starts.

Another object of this invention is to provide an electrodynamic device that functions both as a motor and as a generator for starting an engine and for charging a storage battery et cetera, which electrodynamic device rotates at a relatively high speed as compared with the speed of the engine when starting the engine and rotates at the same speed as the engine when functioning as a generator.

Another object of this invention is to provide an electrodynamic device that functions as a generator and as a motor, wherein the relative speed of the electrodynamic device with respect to the speed of the motor changes when the electrodynamic device shifts its function from that of a starter to that of a generator.

Another object of this invention is to provide a planetary gear system for interconnecting an electrodynamic device to a motor, which planetary gear system automatically changes the relative speed between the electrodynamic device and the motor when the electrodynamic device ceases to function as a starter motor and changes over r to a generator.

Another object of this invention is to provide an electrodynamic device with conductors that extend beyond the rotor, which conductors func-' tion as commutator segments.

7 Claims. (o1. 74 s10) particularly to an electro- Another object of this invention is to provide a commutator wherein the centrifugal force exerted upon the commutator segments is counteraeted by a force pushing against the commutator segments so as to prevent a radialdisplacement thereof.

Another object of this invention is to provide a commutator wherein the commutating surface is positioned inwardly to permit the brush holders and the brushes to be located within the commutator. 7

Another object of this invention is to provide an annular member into which the commutator segments are press-fitted, the annular member surrounding the commutator segments, thereby preventing radial displacement thereof when the commutator segments are subjected to the influence of centrifugal force.

Another object of this invention is to pro-- vide a generator and a starter motor in a single unit, thereby eliminatingexpensive duplication of parts such as shafts, bearings, rotors, stators, commutators, housings and other parts.

Another object of this invention is to provide means for alternating the usage of a rotor both as a driving member and as a driven member or as a starter and as a generator.

Another object of this invention is to provide mechanical operating means for multiplying and transmitting the armature torque to an engine crankshaft.

Another object of this invention is to provide a variable speed changing mechanism wherein the same gears are utilized in transmitting power at more than one speed ratio without shifting gears.

Another object of this invention is to provide a commutator wherein the commutator bars are formed from extensions of the armature conductors.

Another object of this invention is to provide sealing means for a lubricant wherein the gasket is squeezed so as to force it against the surface to be sealed to seal the opening.

Another object of this invention is to provide an electrodynamic device functioning both as a generator and starter motor incorporated into a single unit, having the rotor mounted upon the crankshaft of the engine to be started, so that the rotor may transmit power to the" crankshaft or the crankshaft may transmit power to the rotor. 5

Another object of thi invention is to provide an electrodynamio device functioning as a generator and as a starter motor having the armature mounted on the shaft of the engine to be started and connected thereto by an overrunning clutch or ratchet, so as to allow the armature to drive said shaft for starting purposes and to be driven by said shaft for generating purposes.

Other objects and advantages reside in the construction of parts, the combination thereof and the mode of operation, as will become more apparent from the following description.

Referring to the drawings, Figure 1. is a cross sectional View taken substantially on the line ll of Figure 2.

Figure 2 is a fragmentary cross sectional view taken substantially on the line 22 of Figure 1.

Figure 3 is an enlarged fragmentary cross sectional view disclosing the pawl for governing the movement of the planetary gear system.

Figure 4 is a fragmentary cross sectional view taken substantially on the line 5-4 of Figure 1.

Figure 5 is a fragmentary cross sectional view of aportion of a commutator taken substantially on the line 5--5 of Figure 1.

Figure 6 is a schematic showing of a. modification. disclosing, a. planetary gear system wherein the orbital gears are. provided with radially disposed weights.

In. the drawings, the referencecharacter 29 indicates the end of the crankshaft of an internal combustion engine. The internal combustion engine may be a Diesel type engine or ignition type engine or any other suitable internal combustion engine. The end of the shaft 26 is mounted in a suitable-bearing 22, having mounted thereon a tubular sleeve 2d. The sleeve 25 is 50 mounted that it may rotat with respect to the shaft 20. Thesleeve 2 has-mounted thereon an armature or rotor 2?: that includes a collar 28, having mounted thereon an annular ring 28 providing a support for armature laminations 36, held in. position by upset edges 32 of. the annular ring 28. Each slot inthe laminations 35; supports two windings 7 ii]. Each Winding consists of a copper bar and has a substantially U-shaped contour. One leg of each U-shaped member is seated in the bottom of a slot and the other leg is seated in. another slot and positioned on top of a corresponding winding. In the trade these windings are oftentimes referred to as hairpin windings. The loop ends 42- of the windings id are all positioned on one side of the armature or rotor. In the past, it has been common practice tosolder or fuse the free ends of the hairpin windings to commutator segments. This is the practice that is followed by at least some 'of the automobile manufacturers in connection with starters.

In the device disclosed herein, the ends of the hairpin windings project outwardly from the slots in a substantially straight line. As may best be seen by referring to Figure 5, the ends 40d and 40b of the windings are mounted contiguous to a tapering copper bar or segment ill contacting a strip of insulating material 46, functioning as a spacer member. A ring of insulating material 50, such as mica, surrounds the ends of the windings 40, the copper segments M and the insulating spacer members 48. A suitablesteel ring 52surrounds the ring of insulating material 50.

In order to secure a rigid assembly, the armature, together with the ends of the hairpin windings, the copper bar M and the insulating material, are subjected to a sub-zero temperature, so as to shrink or contract the parts. The ring 52, on the other hand, is heated, so as to cause it to expand. The commutator bar are held in a pi that may be displaced by suitable increments from time to time while the steel ring 52 is press-fitted into position. By this arrangement, the commutator segments and the steel l'lllg constitute a rigid press-fitted assembly, wherein the commutator se ments, consisting of the ends 40a and $51) and the copper bars M, cannot spread outwardly in response to centrifugal force.

The interior of the commutator segments are trimmed or machined, so as to form a smooth internally located commutating surface. The insulating spacer members 26 may be undercut, so as to provide the conventional grooves found between commutator segments.

A reenforcing and centering ring 53, having an L-shaped cross sectional area, is fixedly attached to rotor and has one leg 58a contacting a suitable ring of insulating material abutting the interior of the commutator segments, so as to hold the commutator segments concentrically with respect to the center of rotation of the armature. Instead of L-shaped cross; sectional area, the reenforcing and centering ring may have any other suitable cross sectional area.

Brush holders supporting suitable brushes G2, urged radially and outwardly by springs 64, mounted upon brackets 66-, contact the inner sur face of the commutator segments. The brush holders 68 are secured by suitable screws 68 to annularly mounted insulating segments 10 attached to a suitable end frame or end bell l2 fixedly attached to a stator housing i i, carrying pole pieces I 5, shown schematically.

When the electromagnetic device is used as a motor in starting an internal combustion engine or supplying power to any other suitable device, the rotor of the motor rotates at a much higher speed than the crankshaft of the engine to be started. When the electrodynamic device functions as a generator, it rotates at the same speed as the crankshaft. This variation in speed ratios has been accomplished by the use of a planetary gear system wherein. the spider is held stationary when the electrodynarnic device functions as a motor and wherein the orbital gears are locked so as to cause the spider to rotate at the same speed as the crankshaft and the rotor when the electrodynamic device is used as a generator. The details of the planetary gear system will now be described.

The planetary gear mechanism is mounted between the end frame !8 and the frame 83 of the internal combustion engine. The planetary gear system includes a pinion 82 fixedly attached to the tubular sleeve 24 for rotation with the rotor. The pinion 8'2 meshes with orbital gears 8d, each attached to a flanged sleeve portion 86 integral with a pinion tilt journalled on a bearing- 88 mounted on av pintle 9i) and held in position by a washer 92 seated in a suitable groove in the end of the pintle 9B. The pintle 90 is attached to a thimble S4 welded to a spider 96. The function of the spider 9 5 will be described more fully later. The pinion 13E} meshes with a gear H12 fixedly attached to the hub of a cogged wheel 36 keyed to the shaft. 26. The relative speed ratio between the rotor 25 and the shaft 2!} is dependent upon whether or not this spider 9G is locked for nonrotary movement or is free to rotate when the gears are locked.

As may best be seen. by referring to Figure 3, the spider control mechanism includes a dog or a pawl Ht! mounted upon a pivot H2 mounted in lugs H15. fixedly attached to the periphery of the spider 9.5.. The end l-lfla of the dog or pawl l I?! is heavier than the end Hflb. A suitable spring l l l is used to rotate or bias the dog or pawl H0 in a counterclockwise direction, as viewed in Figure 3. When this dog or pawl is in the horizontal position shown in Figure 1, the end I la is seated in a suitable notch I I 6 in a ring I I3 welded to tongues or projections I20 formed from the end frame I8. As may best be seen in Figures 1, 3 and 4, a ring I22 is mounted between the ring I I8 and the end frame 18. This ring I 22 is provided with inclined extensions or projections I22a that function to eject the end IIIla from the notch IIt whenever power is supplied from the engine to the armature. When the end MM is in contact with the notch I I6 in ring member II8, ring members I I8 and I22, together with the spider 96, rotate in unison. This takes place when the starter drives the engine. When the engine starts it soon accelerates, causing a relative movement between the spider 96 and the ring I22. This causes the rings H8 and I22 to move in a counterclockwise direction relative to members IIOa, as viewed in Figure 4, causing the inclined surface I220 to ac tuate the weighted ends IIIla outwardly against the force of the spring I I I. When the end I Illa is forced outwardly, this spider will begin to spin, causing the end IIOa of the dog or pawl to be thrown outwardly by centrifugal force, so as to cause the end IIIlb of the pawl to engage teeth I30 located inthe side of the gear 8 3. When the end IISbof the pawl is seated in these notches, the gear 84 cannot rotate with respect to the spider and when the gear 84 cannot rotate with respect to the spider, this spider must of necessity rotate in unison with the shaft 20. In so doing, the armature 25 rotates at the same speed as the crankshaft. lhe ring I22 may be adjusted relative to the ring H8 so as to cause the end I Ifla to drop into engagement with the opposite side of the notch.

The adjustment of the ring I22 is moved in unison with a suitable switching mechanism that has not been shown, f6r reversing the direction of rotation of the armature 25. Thus, by this arrangement, it it possible to crank the engine in either direction. By reversing the relative direction of the flux generated by the stator field and that generated by the armature, the direction of rotation of the armature may be reversed, as is well known to those skilled in the art. One of these magnetic fields may be reversed by reversing the current through one of the windings. The switching mechanism for reversing the current from one of the windings is preferably connected to the actuating mechanism connected to the ring I22 for actuating this ring from one position to the other.

In order to confine the lubricants to the proper cavities, a ring I3I is located between the hub of the spider and the bearing I32 in the end frame I8. A. grease seal or oil seal is attached to the end of the shaft 20 and includes a pair of disc-like members I 4!] and I 42 clamping a resilient member I l l, made of neoprene or other suitable material, that may be used as an oil seal. The discs I40 and I42 are held in position by a suitable screw I40 that may be tightened to squeeze the ring I44 against the wall of the cylindrical cavity I48 in the end of the tubular member 24.

In the modification disclosed in Figure 6., a schematic illustration of the orbital gears in the planetary gear system has been shown. A pinion 200 is driven by the armature and meshes with a plurality of orbital gears 202 mounted for rotation on pintles 204 attached to a suitable spider that has not been shown. Each of the gears 202 has been provided with a weight 206, the weights at all times being equally spaced from the axis of rotation of the pinion 200, the axis of the orbit of the orbital gears. By this arrangement, the weights 2% do not tend to produce an unbalanced condition as far as the orbital center is concerned. When the electrodynamic device functions as a starter, the spider stands still while the orbital gears rotate about their respective axis 204.

As soon as the engine starts, so as to transmit power, the spider begins to rotate in a manner similar to that described in connection with the preferred embodiment. As soon as the spider begins to rotate, the weights 205 have a tendency to retard the rotary movement of the orbital gears 202, in that the weights 206 will tend to move outwardly radially with respect to the spider supporting the orbital gears 202 into the position shown in Figure 6. As soon as the centrifugal force exerted upon the weights 206, by virtue of the rotation of the spider about the shaft 20, is greater than the torque tending to rotate these gears, the gears 202 will remain stationary with respect to the spider, thereby causing the spider to rotate in unison with the pinion 200 and with the crankshaft of the engine.

The spider may be locked in position when starting the motor in a manner similar to that disclosed in connection with the preferred embodiment. Instead thereof, an overrunning clutch arrangement may be used to hold the spider stationary while starting the generator. When starting the generator, the spider tends to rotate in one direction. When the engine starts holding the bars in position.

and the engine begins to drive the electrodynamic device, the force exerted upon the spider is in the opposite direction, thereby releasing an overrunnning clutch. Instead of one overrunning clutch, a pair of overrunning clutches may be used, one for locking the spider when starting the engine in one direction and the other for locking the spider when starting the engine in the opposite direction. Whenever the engine is to be started, only one of the clutches is engaged, the other remaining disengaged until the time arrives for starting the engine in the opposite direction.

The two legs of the windings located in the same slot are separated by insulating material throughout their entire length within the slot. The ends 40a and 40b, projecting beyond the slots, need not be separated by insulation. The insulation between the ends sea. and 40b is preferably eliminated, so as to insure a better electrical contact.

Although the preferred embodiment discloses an internal commutating surface, the external surface could be used as a commutating surface by merely rearranging the insulating ring 50 and the iron ring 52, so as to provide a clearance for the brushes. Instead of one external ring, it might be feasible to use two external rings for The commutating surface could then be between the two rings.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. An electrodynamic device adapted to function as a generator and as a starter for an internal combustion engine having a crankshaft, the combination including a bearing mounted on the end of the crankshaft, a rotor journalled on the bearing, a planetary gear system including gears for interconnecting the rotor to the crankshaft so that the planetary gear system interconnects the rotor to the crankshaft, said planetary gear system including a spider mounted for rotation, and means for arresting the rotation of the gears when the crankshaft attains a predetermined speed so as to cause the electrodynamic device to function as a generator.

2. A duo functional electrodynamic device used as a starter and as a generator for an internal combustion engine having a crankshaft, the combination including a stator, a rotor, the rotor being concentrically mounted with respect to the crankshaft, a change speed gear mechanismfor interconnecting the rotor to the crankshaft, said change speed gear mechanism including a planetary gear system having gears for transmitting motion from the rotor to the crankshaft and vice versa, said planetary gear system including a rotatably mounted spider, and means 3 for arresting the rotation of the gears when the crankshaft of the engine attains a predetermined speed so as to cause the electrodynamic device to function as a generator.

3. A duo-functional electrodynamic device used as a starter and as a generator for an internal combustion engine having a crankshaft, the combination including a stator, a rotor, the rotor being concentrically'mounted with respect to the crankshaft, and a planetary gear system for interconnecting the rotor to the crankshaft, said planetary gear systemincluding a pair of solar gears one of which is larger than the other, one of the solar gears being connected to the rotor and the other to the crankshaft, a plurality of sets of orbital gears, each set including two interconnected gears one of which meshes with one solar gear and the other meshes with the other solar gear, a spider rotatably mounted on an axis concentric with the axis of rotation of the rotor, said orbital gears being mounted for rotation on the spider, means for locking the spider in stationary position when the electrodynamic device functions as a starter, and means for locking the orbital gears with respect to the spider when the electrodynamic device functions as a generator.

4. A duo-functional electrodynamic device used as a starter and as a generator for an internal combustion engine having a crankshaft, the combination including a stator, a rotor, the rotor being concentrically mounted with respect. to the crankshaft, and a planetary gear system for interconnecting the rotor to the crankshaft, said planetary gear system including a pinion rigidly connected to the rotor, a second pinion keyed to the crankshaft, orbital gears having one gear meshing with the first pinion and a second gear meshing with the second pinion, said orbital gears being interconnected, a spider mounted for rotation about an axis concentric with the axis of rotation of the rotor, said spider supporting the orbital gears, means for locking the spider so as to hold it stationary when the electrodynamic device functions as a starter, and means for releasing the spider and locking the orbital gears with respect to the spider when the, electrodynamic device functions as a generator so as to cause the rotor to rotate in unison with the crankshaft.

5.v A duo-functional electrodynamicdevice used as a starter and as a generator for an internal combustion engine having a crankshaft, the com,- hination including a stator, a rotor, the rotor being concentrically mounted with respectv to the crankshaft, and a planetary gear system for interconnecting the rotor to the crankshaft, said planetary gear system including a pinion rigidly connected to the rotor, a second pinion keyed to the crankshaft, orbital gears having one gear meshing with the first, pinion and a second gear meshing, with the second pinion, said orbital gears being interconnected, a spider mounted for rotation about. an axis concentric with the axis of rotation of the rotor, said spider supporting the orbital gears, spring-urged means for locking the spider in stationary position when the electrodynamic device functions as a starter, and centrifugal means for releasing the spring-urged means to release the spider so as to permit it to rotate with the rotor when the electrodynamic device. functions as a generator.

6. A duo-functional electrodynamic device used as a starter and as a generator for an internal combustion enginehaving a crankshaft, the com,- hination including a stator, a rotor, therotor being concentrically mounted with respect to the crankshaft, and a planetary gear system for interconnecting the rotor to the crankshaft, said planetary gear system including a pinion rigidly connected to the rotor, a second pinion keyed to the crankshaft, orbital gears having one gear meshing with the first pinion and a second gear meshing with the second pinion, said orbital gears being interconnected, a spider mounted for rotation about an axis concentric with the axis of rotation of the rotor, said spider supporting the orbital gears, and means responsive to centrifugal force for arresting therotation of the orbital gears with respect to the spider when the electrodynamic device functions as a generator.

7. A duo-functional electrodynamic deviceused as a starter and as a, generator for an internal combustion engine having a crankshaft, the combination including a stator, a rotor, the rotor being concentrically mounted with respect to the crankshaft, and a planetary gear system for interconnecting the rotor to the crankshaft, said planetary gear system including a pinion rigidly connected to the rotor, a second pinion keyed to the crankshaft, orbital gears having one gear meshing with the first pinion and a second gear meshing with the second pinion, said orbital gears being interconnected, a spider mounted for rotation about an axis concentric with the axis of rotation of the rotor, said spider supporting the orbital gears, and means for locking the spider so as to hold it stationary when the electrodynamic device functions as a starter, said last mentioned means including a ratchet mechanism having a pair of rings one of which is notched andthe other having inclined teeth, said rings having a relative movement so as to reverse the direction of the ratchet mechanism.

EVERETT P. LARSH.

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

UNITED STATES PATENTS Number Name Date 1,235,046 Nikonow July 31, 1917 1,580,636 Barengi Apr. 13, 1926 2 041,125 Geisse May 19, 1936 2,354,874 Myer Aug. 1, 1944 2,371,193 Sigmund et al., Mar... 13, 1945

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