CA1119226A - Unified generator-compressor assembly - Google Patents

ABSTRACT OF THE DISCLOSURE

A pump such as a vehicle air conditioner compressor has a compressor shaft, a continuously engine-driven flywheel and means such as an electromagnetic clutch for selectively coup-ling the flywheel to the shaft to operate the pump. The fly-wheel also provides a permanent magnet field which field rot-ates with the flywheel and induces in the windings of a rela-tively stationary annular stator assembly an electric voltage in response to the rotating magnetic field. The pump shaft, annular clutch actuating coil, annular stator assembly and permanent magnet flywheel are all generally concentrically disposed and in the order stated. The flywheel is driven any time that the engine is running thereby inducing a volt-age in the stator windings and that flywheel also drives the exemplary compressor when the clutch is actuated.

il~9Z26 The present invention relates ~enerally to a multi-purpose electromechanical device which provides a ~umping function such as might be required in an air conditioning system as well as an electrical energy generating function to obviate the need for, for example, a separately driven vehicle alternator.
This application is related to my United States Patent No. 4,097,754, issued June 27, 1978, for "Short Pitch Alternator", assigned to the assignee of the present invention.
In the past, vehicles have included a prime mover, such as an internal combustion engine, which in addition to supplying energy to drive the vehicle, also provides energy to a number of other devices through a maze of V-belts, pulleys and the like. Specifically, such an engine drives an electrical generator or alternator, a r water pump, a power steering pump, an air conditioner pump or compressor, various anti-pollution devices and perhaps other devices.
The typical alternator will be engine-driven by way of a V-belt and a relatively small diameter pulley, for example, of the order of 2-1/2 inches in diameter.
The alternator typically therefor revolves at a relatively high speed generating a relatively high frequency alter-nating current voltage. With such a relatively high frequency alternating current voltage, stator core losses are relatively high and with such a small diameter pulley, belt slippage is a substantial problem. From at least a size standpoint, larger pulleys and lower frequencies have hereto~ore not been practical.
Compressors for vehicle air conditioning systems are typically also belt-driven from the enyine by way of a cbr/ ~

~1192;~6 pulley, which is selectively coupled to the compressor shaft by an electromagnetic clutch arrangement. Much of the time this electromagnetic clutch is not actuated and the compressor pulley and V-belt are "free wheeling", contributing nothing to the system except frictional losses. As compared to an alternator, the current com-pressor design is of a lesser number of revolutions per minute, greater pulley diameter (a six inch diameter pulley would not be uncommon) and a somewhat larger overall structure. The larger pulley diameter and slower speed reduces belt slippage and related problems.
It is also known in the prior art, for example, in United States Patent No. 2,660,865 to provide a common shaft for a pump and an electrical generator, however, such prior art approaches amounted to little more than placing the two machines end to end with the overall axial length, weight and cost being substantially the sum of those traits for the respective individual components.
Among the several objects of the present invention may be noted the provision of a single electromechanical device which will supplant the typical vehicle generatox and pump; the provision of a space, weight and cost saving arrangement wherein an alternator rotor is rotatably sup-ported on the bearings required for a pump and the stator assembl~ is supported on the pump housing; the provision of an alternator function of reduced frictional and eddy current losses as compared to the above-mentioned alter-~; nator systems; and the provision of an electromechanical divice which provides an alternator function while lessening t,he noise associated with prior art alternators due tobelt slippage and high speed of operation or rapid accel-eration.

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~19Z26 According to the present invention there is provided a unified pump generator for a vehicle engine, the pump generator including a pump having a housing with a face, pump bearing supported in the housing and a rotatable drive journaled in the pumP bearings and extending from the housing face. A rotatable hub member is supported for rotation about the shaft, and a generator stator is mounted on and supported solely by the housing face, the stator positioned in close proximity to the housing face. A generator rotor is fixedly secured to the hub member, the hub member and generator rotor heing rotatably supported by the pump. The rotor is positioned in close proximity to the housing face radially outward of the stator and concentric with the shaft.
Also in general, and in one form of the invention, ; ~ ' cbr/ws - 3 -ll~9Z26 a vehicle air conditioner compressor has a compressor shaft, a continuously driven flywheel which is selectively coupleable to the shaft to operate the compressor, and is capable of generating electrical energy in response to the flywheel rotation due to the provision of a permanent magnet field which rotates with the flywheel, and a relatively stationary annular stator assembly having windings for providing the electric voltage in response ~o the rotating magnetic field.
The exact nature of the present invention will become more clearly apparent upon reference to the following detailed specification taken in connection with the accompanying drawings in which: .
Fig. 1 is a perspective view of an electromechanical device which embodies the present invention in one pre-ferred form;
Fig. 2 is an exploded view of the electromechanical ': :
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~ cbr/,--1~9226 device of ~ig. l;
Fig. 3 is a side view partially in cross-section of the electromechanical device of Fig. l;
Fig. 4 is an electrical schematic diagram par~ially in block fonm illus.rating one electrical arrangement for the al-texnator of the present invention; and Fig. 5 is a side view partially in cross-section of a variation on the electromechanical device o the present invention.
In the several drawing views like reference numerals identify like parts. The following is illustrative of the inven~ion in one form and is not to be construed as limiting in any manner.
In a vehicle the prime mover, such as an internal co~-bustion engine, has pulley 11 dri~en, for example, by the engine cran~ shaft, and in Fig. 1 that pulley is coupled by way of V-belt 13 to drive another pulley 1~ whenever the engine is running. Pulley 15 drives the alternator of the present invention whene~er the engine is running, and when clutch arrangement 17 is actuated, also drives an air con-ditioner co~pressor 19. Three leads 20, 22 and 24 extend from Delta connected alternator phase windings and a dutch energizing or control lead 26 extends from a clutch act-uating elect~omagnet to a the~mostat or control switch 32 for clutch control. Tha other clutch energizing lead may be grounded. ~hus, Fig. 1 illustrates a unified pump-gener-ator structure and such a combined arrangement provides a - compressor func~ion for a vehicle air conditioning system as well as a generator or alternator function fox supplying the vehicle electrical needs. The detailed construc~ion and operation of such a combined arrangement will be most easily understood by considering Figs. 2 and 3 together.
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~ ~ ~9Z26 The pump or compressor 19 ha~ a housing 21 from which there is axially extending a drivable compre~sor actuating ~haft 23, rotation of whi~h actuates the compre~30r in a eonventional manner. Housing 21 also has fixedly at~ached thereto an annular generator ~tator a~sembly 25 which com-prises a slotted laminated magnetic core 27 having winding~
29 disposed in the core 810ts. Still further housing 21 has affixed thereto annular coil 31 which when energized creates a magnet$c field to actuate clutch 17. Shaft 23 may be thought of as rotating about imaginary axis 33 and the annular coil 31 as well as the generator ~tntor a~Rembly 25 are attached to housing 21 concentric to one another and to axi8 33. S~milarly, these last two annular ~mbers are eoneentric with ¢o~pressor erank shaft 23.
Shaft 23 is fixed, for example, by key 35 ~n keyway 37, by threading, or both, to member 39. Such threaded ~ttaehment may be facilitated by nut 41 and threads 43 on the co~pre890r crank shaft. Still further, fixedly conn~cted to member 39 and spaced therefrom i8 clutch support plato 45. Clutch support plate 45 may be ~onnectod to member 39, for example, by bolts or rivets 47, and this bolt or rivet 47 may al80 affix one end of spring 49 to the clutch support plate. A~
illustrated three 8uch ~pring~ 49 have thelr ends re~ote from the bolts or rivet~ 47 connected to clutch plate 51. If ~haft 23 is rotationally motionles~ ~o are member 39, clutch ~upport plate 45, leaf springs 49 and clutch pla~e 51.
However, clut¢h pl~te 51 may move axially somewhat due to the flexin~ of springs 49 when the annular coil or clutch actuating coil 31 i~ energized. Energizing zoil 31 draws clutch plate 51 axially toward ~ide ~urf~ee 53 of pulley 15 frictionally to engage surface 53 thereby connectlng rot-atable member 55 ~0 compres~or crank shaft 23. When coil 31 is deenergized, for example, by a manual or thermo~taticcontrol (not shown), clutch plate 51 under the influence of springs 49 return~ to it~ rest po~ition and no longer frictionally engages surface 53. In thi rest position compressor 19 is inactive, however, rotatable member 55 free wheels about the axis 33 on a bearing 57.
Rotatable member 55 include~ no~ only pulley 15, but also bearing retainer spring 59, and generator rotor portion 63, which includes flywheel 65 and a series of permanent magnet~ 67, which together form a multi-pole rotor for the alternator. Flywheel 65 may have the perma~nt magnet~ 67 adhe3ively bonded to it~ interior r~m. Flywheel 65 and its permanent magnets 67 are again concentric wi~hin reasonable limits with axis 33. Flywheel 65 may be provided with a pluxality of air passing apertures 69 for cooling the gen-erator stator portion. A cooling fan may be mounted on member 65 to force air through holes 69 for applications in which the vehicles main cooling fan is not favorably located with re3pec~ to this alternator. The air pas~ing apertures have web~ lying therebetween and these web portion~ may be bent to form a fan type structure.
When the fixed annular coil 31 is not energ~zed to cr~ate a magnetic field, clutch 17 is motionless and the compres~or 19 i~ quleseent, even though the engine i8 oper-ating and driving belt 13, to cause pulley 15, retainer 59, flywheel 65, and its associa~ed permanent magnets 67 to ro-tate about the ~tator 25 and indu~e a voltage in the windings thereof. Bnergization of the coil 31 cau~e3 clutch plate 51 to engage ~urface 53 of pulley lS and additlonally, fric-tionally to drive clutch 17 and compressor crank ~haft 23.
Axial space ~aving i~ acco~pli~hed by the nesting ofgenerator and compressor portions which is most readily seen in Fig. 3. Thu~ generator elements, such as the permanent magnets 67 and stator 25, including stator lamination~ 27 and windings 29, are nested wi~h and overlap somewhat mag-netic clutch actuating coil 31 as well as bearing 57 and ~haft engaging member 39. A substantial space saving and weight ~aving over merely an end to end connection of a generator and compressor i~ thereby achieved. It will be understood that electromagnets energized through slip rings on member 39 may be substituted for permanent magnets 67.
While many winding arrangements c~uld be employed i~
the annular stator as~embly 25, typical known alternators employ windings connected in a three-phase wye or star con-figuration with an ungrounded center point of that wye. ~ix diodes are employed to couple such a wye connection ~o, for example, a vehicle storage battery with three of those diodes conducting current from one terminal of the battery to each of the three re~pective winding leads while three other diodes couple those same three re~pectiYe winding leads to the other side of the battery. Such a known winding connec-tion would be perfectly suitable for u~e in the present in-vention, however, Fig. 4 illustrates another manner in which the winding~ may be connected and which connection may be pref~rred ln ~ome vehicle environments.
In Fig. ~, the three windings 29 are Delta connected with eaoh winding junct~on, such a~ 71 coupled by way of a diode 73 to the pos~tive terminal of storage battery 75.
Voltage x~gulating circuit 77 may ~ense the voltage across ~he battery and provide appropriate gating signals to silico~
controlled rectifi2r~, such as 79, 30 as to pass or block charging current, depending upon the state of charge of the battery 75.
In Fig. 5 a fan blade 80 i~ supported on a shaf~ 82 1~1!3ZZ6 oonnected to a pump 84 such as a vehicle water pump having an impeller 87. Frame 84 of the water pump suppor~s ~tator laminations 86 having windings 88 disposed therein. A
pulley 90 i8 engine driven and in turn drive~ a flywheel 92 s~pporting permanent magnet3 94 to provide a generator or alternator operating ~ub-Qtantially as previously described.
Mounting tha alternator directly ~ehind the vehicle cooling fan in th~s manner allows excellent cooling of the alternator winding~, silicon controlled rectifier~ and diode~. The alternator rotor ~ con~on with the vehicle ~an and water pump ~haft.
ffl us, while the present invention has been described with respect to a specific preferred embodiment, numerous modification~ will suggest themselves to thD~e of ordinary skill in the art. For example, the illustrated preferred embodiment is of an alternator-compre~sor, however, pumps found in vehicles other than an air conditioner cGmpre~sor pu~p might equ~lly well be integrated w~th an alternator, ~r other type generator advantageously according to the principles of the pre~ent invention. Al~o a bracket may support the alternator when no compre~sor i8 pre~ent.
Aocordingly, the ~cope of the pre~ent invention 18 to be m~asured only by that of the appended claim~.

1. A unified pump-generator for a vehicle engine comprising:
a pump including a housing having a face, pump bearings supported in the housing and a rotatable driving shaft journaled in the pump bearings and extending from said housing face;
a rotatable hub member supported for rotation about said shaft;
a generator stator mounted on and supported solely by said housing face, said stator positioned in close proximity to said housing face; and a generator rotor fixedly secured to said hub member, the hub member and generator rotor rotatably supported by the pump, said rotor positioned in close proximity to said housing face, radially outward of the stator and concentric with said shaft.

2. The assembly of claim 1 wherein said driving shaft includes clutch means for starting said pump independently of said generator.

3. The assembly of claim 2 wherein said rotor surrounds said stator assembly, said clutch means including an operating coil concentrically surrounding said shaft, said stator assembly concentrically surrounding said coil.

4. The assembly of claim 3 wherein said clutch means includes clutch plate means for drivingly engaging said rotatable hub in response to energization of said coil, said clutch plate means being connected to said shaft and rotatable therewith.

5. The assembly of claim 1 wherein the pump comprises a water pump.

6. The assembly of claim 1 further comprising a vehicle fan supported on the driving shaft for rotation therewith.