US2043215A - Unitary motor-pump assembly - Google Patents

Description

June 2, 1936.V R. T. SMITH ET A1.

V UNITARY MOTOR PUMP ASSEMBLYV Filed May 20, 1955 5 Sheets-Sheet l INVEIXTOR. .5m z t Il 2V# viii .assell mi. @w

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5 Sheets-Sheet 2 Filed May 20, 1933 R. T. SMITH ET AL UNITARY MOTOR PUMP ASSEMBLY June 2, 1936.

. INVENToR. g/Yzzfisell mzfh Jfder L Tarleton l dwf/,W VWM/u1? ATToRls/EYSl June 2, 1936. R, T. SMITH ET AL 2,043,215

UNITARY MOTOR PUMP ASSEMBLY Filed May 20, 1933 5 Sheets-Sheet 3 ATTORNEY.

Patented June 2, 1936 NITED STATES PATENT OFFICE UNITY MTR-P l Application May 20. 1933, Serial No. 671,984

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This invention relates to pumps, compressors `and the like, and driving means therefor, and

more particularly to an improved motor-compressor unit so constructed that it may be hermetically sealed, and adapted especially for use in refrigerating systems.

An important object of the invention is the incorporation in such an hermetically sealed motor-compressor unit of improved means for lubricating the working parts, for controlling and guidingthe flow of oil or other lubricant, and for maintaining the lubricant in and returning it to a desired portion of the housing orenclosure.

A further object is the provision of improved means for supporting and journaling the moving parts.

Still another object is the provision of an improved casing construction for such a unitary motor-compressor.

Still further objects will readily occur to those skilled in the art upon reference to the following description and the accompanying drawings in which Figure 1 is a vertical longitudinal section taken substantially thru a motor compressor unit incorporating the principles of this invention.

Figure 2 is a section taken substantially on the l line 2-2 of Figure 1 and looking in the direction of the arrows;

unit shown in Figures 1 and 2,

Figure 4 is a vertical section taken substantially on the line 4-4 of Figure 1 and looking in the direction of the arrows.

Figure 5 is a schematic diaggm of the motor connections.

Referring now to the drawings, reference characters I8 and Il designate the two main sections of a casing which houses the entire unit. The section I0 may be termed the motor casing section, and the part I I the compressor casing section, since the indicated portions of the housed apparatus are principally contained in the sections stated. The two casing sections are substantially cylindrical and provided with threadedly intertting portions (l2) enabling their being screwed together to form a single housing, as shown in Figures 1 and 2. 'Ihe threads may be tapered, and solder may be applied to the joint as well, as at I4, to insure hermetic sealing. i

Axially thru the substantially cylindrical housing so formed extends a xed shaft I6 supported at one end by a boss I1 cast in casing section I8 and at the other by a support integral with the (iCl. 230--58) casing section Il, the bore in which the shaft is fixed at this end communicating withatrough-like oil channel 28 to which oil is delivered when the machine is in operation, in a manner presently to be described. Shaft I6 is axially drilled as at I8 to provide an oil channel which communicates with the trough 20, into which the end of the shaft projects, so that oil is conducted through the entire length of the shaft.

Journalled on the fixed shaft i6 is a hollow shaft 2l, carrying at one end and within the motor casing section the rotor 22 of an electric m'otor, shown as of the squirrel cage induction e type. As shown in Figure 5, the motor is connected for condenser starting in a manner which eliminates from the housing all sparking contacts and all moving electrical parts except the rotor. The windings of the motor comprise a running winding 15, a starting winding 16, and a control winding 11. The control winding is energized only by counter electromotive force. In a series with the starting winding is a condenser 18 of relatively large capacity. The 115 microfarad size indicated seems correct for a motor of about one-rifth horse power. The switch 19 which controls the current to the starting Winding is actuated by and forms part of a differential relay, one winding (80) of which tends to close the switch and is in series with the supply to the main or running winding. When the switch 8l is closed, relay winding 8U is energized and Switch 19 thereby closed. This energizes the starting winding 16, the current in which leads the voltage by reason of the presence of condensers 18, while this split-phase eiect starts the motor reliably on single phase supply in a manner which will be readily understood.

It will be appreciated that the current induced in the auxiliary control winding 11 will be at a minimum when the motor is first started but builds up with the counter electromotive force as the current drops off in windings 15-16. At the start the current in relay winding 82, which tends when energized to open switch 19, will also be light. As the motor gathers speed the counter electromotive force builds up; the current in windings 15, 16, and 80 falls away, and concurtrently increases in winding 11 and so in relay solenoid 82, which when fully energized overcomes the force exerted by the now weaker solenoid 88, thereby opening the switch 18 and cutting out the starting winding 15.

- The motor terminals 85 extend through the end of the casing, as best shown in Figs. 1 and 2, and a fan motor 81 carried by and upon the outside of the same end of the casing is supported by a plate 88 which also serves as a terminal cover. The same terminals may be used for making connections to the fan motor, the shaft 89 of which is adapted to carry a cooling fan (not shown).

The construction of the compressor generally follows that disclosed in the patent to Russell T. and Charles H. Smith, No. 1,890,238, issued December 6, 1932. Upon its end Within the compressor casing section the hollow shaft carries an eccentric encircled by a strap 3|', which is formed as an integral end of a connecting rod 3I coupled as by means of a Wrist pin 32 to a double piston unit comprising opposed outwardly facing pistons 33-34 rigidly connected as by means of a rib 35 integral with both, and slotted as at 36 to clear the shaft I6. The opposed cylinders 3'I-38 in which the pistons may travel may be formed integrally with casing section II. Suitable cylinder heads as 40-4I are secured as by means of cap screws 42 over the open ends of the cylinders, and carried by the heads are outlet nap valves 43-44 caged in enlarged bores in the heads and held seated against the valve orifices (undesignatcd) in valve plates 45-46 by means of compression springs 41-48, The outlets are connected as by means of channels 49-50-5I to a bore 52 opening in the end of casing II and in which the outlet coupling 53 is tightly secured as shown in Figures 1 and 3.

The inlet ports 55-55 opening in the side walls of the cylinders are arranged to be uncovered by the pistons as the latter approach the bottoms of their strokes to admit a charge in the well known manner. Ports 55-56 are connected by means of a channel 51 formed in casing section I I, to which channel the inlet pipe 58 is connected. The inlet pipe opens directly into the interior of casing II, its upstanding open end being angled in a manner adapted to prevent the splashing of oil thereinto, as will subsequently become apparent, and the inlet to the unit as a whole is directly thru the wall of casing section I I, an inlet coupling 54 being shown attached t0 and over an inlet opening (not shown) in the wall (Fig. 3).

The bottom of casing section I I forms an oil pan which may be drained by means of plug 59 and into which dips an oil splash-er 60 formed integrally with and projecting downwardly from the connecting rod strap 3l.

Also carried by the shaft 2I is a counterbalance weight 62. An oiling disc 6I, rotatable with the shaft is mounted thereupon adjacent the counterweight and fastened to the latter, as shown in Figure 2. The disc 6I also dips into the oil in the bottom of the casing and during operation of the compressor serves to throw against the walls by centrifugal force the oil it picks up. A certain amount of such oil is thrown into a channel I9 cast integrally upon the side wall of casing II as best shown in Figure 4. The channel I9 is inclined downwardly toward and communicates with the transversely extending trough 20, so that oil thrown into channel I9 by the disc 6I is conducted to trough 20, whence by reason of the previously mentioned communication between channel 20 and the bore I8 in the xcd central shaft, by reason of the intersection of the shaft-supporting aperture and the trough, the oil is led to bore Ill and ows along the entire length of the xed shaft therethrough. At desired points along the xed shaft radially extending passages, as I8. are formed extending through its walls and connecting the central oil channel I 8 with the bearing surfaces of shafts I6 and 2I. Spirally cut exterior oil grooves may be formed upon the bearing surface of shaft I6 and communicating radial and spiral grooves are 5 arranged at both the compressor and motor ends of journaled shaft 2 I. Escape channels 23 extend through the wall of shaft 2I between the rotor 22 and boss I'I, opening into the interior of casing section IIJ, and with these one or more of the 10 radial channels I8 may communicate. Through apertures 23 oil in properly limited quantities may escape into the interior of the motor casing section, being also forced thereinto and flow through the central channel assisted by centrifu- 15 the space between such shaft and the aperture 25 in partition through which it extends, is prevented by a sleeve-like sealing ring 66 frictionally held against the partition at its one end and against the rotor 22 at the other, such friction being supplied by a compression spring 61 trapped between the motor end of tubular shaft 2| and the head of casing section I0, and positioned, as best shown in Figure 2, by' the boss I1. It will be seen that the spring imposes end thrust upon the shaft urging it to the right as viewed in the 35 drawings.

As above stated, the escape of a certain amount of oil in the motor section of the casing is provided for, in order that the motor may perform the valuable function of warming the oil. Pref- 40 erably, however, means are provided for preventing the oil level in this casing section from rising to such height that oil occupies the gap between the rotor and stator of the motor, and for returning the excess oil to casing section II. this purpose a channel 'III (Figure 1) extends through partition 65, opening at its lower end upon the motor side and closer to the oor of the casing than the bottom of such annular gap.

At its upper end the channel 'I0 opens upon the 50 compressor side near shaft 2|. Since the compressor inlet opens, as above stated, directly in casing section II, the pressure is reduced in such section as soon as the compressor is started, and

any oil in casing section ID above the mouth of 55 channel I0 is accordingly quickly drawn through such channel into the compressor section of the casing whenever the unit is started, since the only other passage connecting the casing sections y(that through the oil bore I8 and connected 60 channels) is relatively very restricted. A circulation will be seen to be so maintained, oil being constantly delivered to the casing section I0 through apertures 23 when the unit is running and withdrawn thru passage 10.

By reason of the unitary enclosure of both compressor and motor in a common housing, and the provision of a common lubricant circulation system, in the manner disclosed, the unit when used 70 in a refrigerating system may be provided with a generous supply of oil without danger of harmful effects resulting from interaction of the oil and refrigerant at low temperatures. There is no necessity, as in other arrangements, of pro- For 45 aotaara vidlng a special heater to prevent the oil from being cooled by the refrigerant to an undesirably low temperature, as the heat generated by the motor is sumcient for the purpose. The current saving thus effected is considerable, as even a small heater is wasteful of current.

Now having described the invention and the preferred embodiment thereof, it is to be under'- stood that said invention is to be limited, not to the specific details herein set forth, but only by the scope of the claim which follows.

What we claim is:

lin an enclosed motor-compressor unit, a casing, a partition therewithin dividing'the casing into separate sections, a motor within one of said sections and including a portion which generates heat when the motor is running, a compressor within another section, a common shaft assembly extending into both such sections and supporting parts of both the motor and compressor, said shaft having a longitudinal oil channel therein, and also having an inlet communicating with said oil channel within the compressor section,

and an outwardly extending outlet formed in a rotatable portion of the shaft within the motor section and terminating in an exposed surface of the shaft, the compressor section having an oil reservoir therein, means for feeding oil from said reservoir to the channel inlet, whereby upon rotation of the shaft portion having said outlets therein centrifugal force tends to draw oil through the channel from the inlet and discharge it into the motor section, the compressor having an inlet opening into the section in. which it is housed, and the partition having an opening therethrough connecting said sections and opening in the motor section at a height allowing the maintenance of a desired quantity of oil in the motor section to be heated by said portion which generates heat, whereby the compressor tends to draw all oil above the level of the inlet opening into the section in which it is' housed by reducing the pressure therein.

RUSSELL T. SMITH. FREDERIC L. TARLETON.

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