US2720357A - Air compressor and oil pump therefor - Google Patents

Description

Oct. 11, 1955 R. J. BUSH AIR COMPRESSOR AND OIL. PUMP THEREFOR 2 Sheets-Sheet 1 Filed March 8, 1951 INVENTOR. Rankin J Bash A T TORNEY Oct. 11, 1955 R. J. BUSH 2,720,357

AIR COMPRESSOR AND OIL. PUMP THEREFOR Filed March a, 1951 2 Sheets-Sheet 2 to LO "Q:

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J. Bush A T TORNE Y United States Patent AIR COMPRESSOR AND OIL PUMP THEREFOR Rankin J. Bush, Greensburg, Pa., assignor to Westinghouse Air Brake Company, a corporation of Pennsyl- Vania Application March 8, 1951, Serial No. 214,512

10 Claims. (Cl. 230206) This invention relates to air compressors and particularly to oil pumps therefor. This invention is particularly concerned with air compressors of the type used for diesel locomotives wherein said compressor is coupled between a driving diesel engine and a driven auxiliary device such as a fan or an electric generator with a shaft of said compressor serving as a driving connection between the engine and an auxiliary device. Acompressor of this type is the 3-CD air compressor shown and described in DescriptiveLeaflet No. 2459 published by The Westinghouse Air Brake Company, Pittsburgh, Pa. Heretofore, when it was desired to service the oil pump on the 3-CD compressor it was necessary to remove the end cover of the compressor and in so doing to disconnect the shaft coupling and thus disturb the bearings.

It is an object of this invention, therefore, to eliminate the necessity of disturbing either the end cover or shaft coupler when servicing the oil pump of the compressor.

Another object is to provide a valve assemblage associated with the oil pump which assemblage may be removed and returned as a unit.

Other objects and advantages will appear in the following more detailed description of the invention.

In the accompanying drawing; Fig. 1 is a side elevation View, mainly in outline and partly in section, of a compressor having an oil pump embodying the invention; Fig. 2 is an enlarged sectional View of a portion of Fig. l; and, Fig. 3 is a sectional view of said oil pump taken on the lines 3-3 of Fig. 2.

Referring now to the drawings, the compressor comprises a sectional casing 1 which is provided with a crank chamber 2 in opposite walls of which anti-friction bearings 3 are secured for supporting a rotatable crank shaft 4 which extends exteriorly of said casing through two opposite openings, one of which is designated at 5 in an end cover 6 which is secured to the casing by means of bolts 7 and which carries one of said bearings. A packing ring 8 serves to seal the space between end cover 6 and crank shaft 4 and prevent lubricant from flowing exteriorly of the casing 1.

The crank shaft 4 is provided with a counter-balanced crank arm 9 having a crank pin 10, to which is connected in a usual manner three connecting rods 11 for reciprocating, respectively, two low stage pistons (not shown) and one high stage piston (not shown) in their respec tive cylinders, 71 and 72 (Fig. 1), to eifect two stage compression of air as the crank shaft is rotated.

Connecting rods llare provided with individual bearings 13 engaging crank pin 10, to which bearings fluid lubricant is adapted to be supplied from crank chamber 2 by means of a reciprocating pump 15 operated by the crank shaft 4 upon rotation thereof.

Pump 15 comprises a tubular piston 16 pivotally mounted on a cam portion .17 of the crank shaft 4 at one side of the crank arm 9, which portion is eccentric to the center of rotation of crank shaft 4. Thus, rotation of crank shaft4 causes piston 16 to be reciprocated within a piston chamber 18 formed in a cylinder or casing member 19 which is rockably mounted by means of a trunnion portion 20 within a bore 21 formed in the casing 1 near the bottom of the crank chamber 2 to permit angular movement of piston 16 in following the movement of the crank pin 10.

The piston 16 is further provided with a longitudinal bore 23 which is open at its upper end to an internal annular groove 24 surrounding the crank pin 10. The groove 24 connects to a passage 25 in crank shaft 4 which passage leads to rod bearings 13 and thence through ports 26 in bearings 13 and passages 27 in connecting rods 11 to respective wrist pins (not shown). The bore 23 is also open at its lower end by way of radially extending ports 28 in the piston member 16 and registering ports 29 in the cylinder member 19 to a pair of cushion chambers 31 formed in the cylinder member 19 on opposite sides of piston 16. The bore 23 also is constantly connected through ports 32 in piston 16 to a lubricant supply passage 33 formed in the cylinder or housing member 19.

Snugly fitted in a bore 34 in the trunnion portion 20 and in coaxial alignment with bore 21 is a valve assemblage 35 which comprises a body portion 36 having operably mounted therein an inlet valve 37, a discharge valve 38 and a release valve 39.

The inlet valve 37 is a poppet type valve contained in a chamber 40 which is connected through a passage 41 to a chamber 42 open to chamber 18 through a port 43 and is arranged to normally close communication between chamber 40 and a chamber 44, the latter chamber being connected to a strainer assemblage 45 through connecting passages 46 formed in body portion 36, casing 1 and a body portion 47 of the strainer assemblage. The inlet valve 37 is provided with a stem 43 which extends downwardly through a bore 49 formed in the body portion 36 into crank chamber 2. A spring seat 50 is mounted by means of a snap ring 51 on the lower end of stem 48 and supports a spring 52 which engages body portion 36 so as to constantly urge inlet valve 37 toward a closed position.

The strainer body portion 47 has a cylindrical end portion which is received in the bore 21 and is locked therein by means of a headed bolt 53 screwed into a tapped bore (not shown) in the casing 1 and passing through registering slots in the wall of bore 21 and the strainer body portion 47. The entrance to passage 46 from chamber 2 is covered by a screen 54 which is secured in place by a retainer ring 55.

The discharge valve 38 is of'the disk type arranged to engage an annular seat rib 56 surrounding a passage 57 and thereby to normally close communication between chamber 42 and a discharge chamber 58 in response to pressure of a spring 59 which constantly urges valve 38 toward its seated position. The discharge chamber 58is in permanent communication with passage 33,

which, in addition to being constantly open to various bearing surfaces via lubricant conveying passages 23, 25, etc., as previously described, also leads to the seating surface of release valve 39.

The release valve 39 is a disk type valve arranged to normally engage an annular seat rib 60 surrounding the mouth of a branch of passage 33 in response to pressure of a spring 61 operatively engaging the opposite face of valve 39 and a spring seat 62 held in place by a snap ring 62a. The spring side of release valve 39 is open tocrank chamber 2 through passage 65 in seat 62 and a passage 20a in trunnion 20.

A dowel pin 63 is provided in the end of body portion 36 adjacent release valve 39 for insertion in a suitable bore 64 in trunnion portion 20 to insure the proper align- Patented Oct. 11, 1955 3 ment'and registration of the passageways and chambers above mentioned in the associated parts when assembled.

It should be noted that the inlet, discharge and release valves are all mounted in the body portion 36 so as to be well within the clearance limits of said body portion.

In operation, the crank shaft 4 is rotated to operate the pistons (not shown) in the cylinders 71 and 72 and thereby the inlet and discharge valves (not shown) of the compressor to supply compressed air to any suitable receiver (not shown) in the usual manner. As the crank shaft 4 is rotated, the piston 16 is reciprccated in substantially a vertical direction in the cylinder member 19. Upon effecting an up-stroke of the piston 16 from the position in which it is shown in the drawing, fluid lubri: cant is drawn from crank case chamber 2 through screen 54 and passage 46, past the inlet valve 37 into chamber 42, whence it flows through port 43 to chamber 18. Upon effecting a down-stroke of piston 16 fluid lubricant is forced from chamber 18 through port 43, passage 57, past valve 38 into chamber 58, whence it is driven through outlet passage 33 and slotted port 32 to bore 23. From bore 23 the fluid lubricant flows to groove 24 for lubricating the bearing contact between piston 16 and cam portion 17. From groove 24 fluid lubricant is conducted through passage 25, the three ports 26 in connecting rod bearings 13, and passages 27 in connecting rods 11 to the wrist pin bearings (not shown) for lubricating same.

During the latter part of the down-stroke, ports 28, 28 in the piston 16 register respectively with ports 29, 29 leading to their respective air cushion chambers 31, 31. Fluid lubricant flows by this route into chambers 31 until blocked by the opposing pressures of air trapped in said chambers. As the up-stroke of the piston is started oil returns from the said chambers as the pressure in bore 23 reduces, thereby smoothing out pulsating in oil pressure.

Fluid lubricant thus supplied to outlet passage 33 is also conducted to the seating side of release valve 39. When the fluid pressure of lubricant becomes great enough to overcome the opposing force of spring 61, release valve 39 will unseat to permit excess lubricant to flow back to the crank case chamber 2 by way of port 65 in spring seat 62 and port 20a.

Now, if for any reason such as for servicing, it is desired to remove the valve assemblage 35, it is necessary to first drain the crank chamber 2 of fluid lubricant in the usual manner and then remove screw-thread means 66 (Fig. 3) so that a cover plate 67 may be removed from one side of the compressor casing to gain access to the crank chamber 2. The bolt 53 should then be re: moved so the filter assemblage may be removed through an opening 68 formerly closed by the cover plate 67.

The bolt 53 is provided on one end with screw-threads (not shown) which correspond to screw-threads 70 pro-. vided in a recess 71 formed in the adjacent end of body as a unit and with disturbing but few other parts in so doing.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In an air compressor having an air compressing piston, a crank chamber, a crank shaft mounted in said crank chamber operatively connected to said piston for reciprocation thereby, and a pump comprising a casing having oil inlet and outlet passages and an oil pumping piston for drawing oil through the inlet passage and discharging same through the outlet passage to wearing friction parts of the compressor and a valve assemblage for controlling flow of oil through said passages and also the pressure of oil delivered by said pump mounted in and removable from said casing as a unit, said assemblage comprising a body portion slidably mounted in a bore in said casing and having inlet and outlet ports registering, respectively, with said inlet and outlet passages, inlet valve means mounted within the limits of said body portion controlling communication between said inlet passage and said pumping piston, discharge valve m ans m un d thin h lim s 9 d ody p tio controlling communication from said pumping piston to said outlet passage, and release valve means mounted within the limits of said body portion operative in re sponse to an increase in Pressure of oil flowing from said pumping piston above a certain degree to open communication from said pumping piston to said crank chamber.

2. In an air compressor having an air compressing piston, a crank chamber, a crank shaft mounted in said crank chamber operatively connected to said piston for reciprocation thereby, and a pump comprising a casing having oil inlet and outlet passages and an oil pumping piston for drawing oil through the inlet passage and discharging same through the outlet passage for lubricating friction surfaces of said piston and crank shaft, and a valve assemblage for controlling the flow of oil through said passages and also the pressure of oil delivered by said portion 36. Thus the valve assemblage 35 may be re-.

moved by inserting the bolt 53 into the recess 70 and advancing said bolt until sufficient connection is obtained between the two to enable one to withdraw the valve assemblage 35 from the bore 34, then to remove the assemblage through opening 68 to the exterior of the casing 1.

Upon replacing the valve assemblage 35 in its operative position, the order of procedure is reversed, taking care, however, that the dowel pin 63 is inserted in the bore 64 so that the proper port and passage registration is obtained.

From the foregoing, it is apparent that a simple and effective valve assemblage is provided for controlling the flow of fluid lubricant to the oil pump and from the pump to various friction services at the proper desired pressures and said assemblage may be removed and replaced easily pumping piston mounted in and removable from said pump as a unit, said assemblage comprising, a body portion slidably mounted in a bore in said casing and having inlet and outlet ports registering, respectively, with said inlet and outlet passages, inlet valve means mounted wholly within said body portion controlling communication between said inlet passages and said pumping Piston, discharge valve means mounted wholly within said body portion controlling communication between said pumping piston and said outlet passage, and release valve means mounted wholly within said body portionoperative in response to an increase in pressure of oil flowing from said pumping piston above a certain degree to open communication from said pumping piston to said crank chamber and operative upon a decrease in pressure of oil supplied ,by said pumping piston below said certain degree to close such communication.

3. In an air compressor having an air compressing piston, a crank chamber, a crank shaft mounted in said crank chamber operatively connected to said piston for reciprocation thereby, and a pump comprising a casing having oil inlet and outlet passages and an oil pumping piston for drawing oil through said inlet passage and dish gi g it through said outlet passage for lubricating friction surfaces of said piston and crank shaft with oil under pressure, a valve assemblage removable from said crank chamber laterally of said crank shaft as a unit, said assemblage comprising I a body portion slidably mounted in a bore wholly within the limits of said casing and removable therefrom in a direction parallel to the axis of rotation of said crank shaft and having inlet and outlet ports adapted to register, respectively, with said inlet and outlet passages, inlet valve means mounted wholly within the limits of said body portion controlling cnmmunication from said inlet passage to said pumping pi on, disch rge al e me s "mounted W l y thin the limits of said body portion controlling communication from said pumping piston to said outlet passage, and release valve means mounted in said body portion operative in response to an increase inoil pressure delivered by said pumping piston above a certain degree to open communication from said pumping piston to said crank chamber.

4. In an air compressor having an air compressing piston, a crank chamber, a crank shaft operatively connected to said piston for reciprocation thereby, and an oil pump comprising a casing having oil inlet and outlet passages for flow of oil from said crank chamber to friction surfaces of said piston and crank shaft, said crank chamber having an opening in its side adjacent said oil pump, a removable cover plate effecting closure of said opening, a valve assemblage mounted in said pump for controlling the flow of oil to and from said pump and also the pressure of oil flowing from said pump, said valve assemblage being removable as a unit lengthwise from said casing and sidewise from said crank chamber through said opening, and comprising, a body portion slidably mounted in a bore in said casing and having oil inlet and outlet ports for registry, respectively, with said inlet and outlet passages, inlet valve means for said pump mounted within said body portion controlling communication through said inlet passage and port, discharge valve means for said pump mounted within said body controlling communication through said outlet port and passage, and release valve means for said pump mounted within said body portion controlling communication from said pump to said crank chamber.

5. In an air compressor having a crank chamber, an air compressing piston, a lubricant pump comprising a pumping piston for pumping lubricant from said crank case to friction parts of said compressor, and a crank shaft mounted in said crank chamber for operating said pistons, a valve assemblage for controlling flow of lubricant from said crank chamber to said lubricant pumping piston and discharge of lubricant by said pumping piston, a strainer assemblage for conducting and filtering lubricant from said crank chamber to said valve assemblage, and screw-thread means for mounting said strainer assemblage in said crank chamber for cooperation with said valve assemblage, said valve assemblage comprising a body portion slidably mounted in a bore in said pump and removable therefrom as a unit by the use of said screw-thread means, inlet valve means mounted within the limits of said body portion in an inlet communication from said strainer assemblage to said pumping piston, and discharge valve means mounted in said body portion in a discharge communication from said pumping piston to said friction parts.

6. In an air compressor having a crank chamber, an air compressing piston, a lubricant pump comprising a casing and a pumping piston therein for pumping lubricant from said crank case to friction parts of said compressor, and a crank shaft mounted in said crank chamber for operating said pistons, a valve assemblage for controlling flow of lubricant from said crank chamber to said lubricant pumping piston and discharge of lubricant by said pumping piston, a strainer assemblage for conducting and filtering lubricant from said crank chamber to said valve assemblage, and screw-thread means for mounting said strainer in said crank chamber for cooperation with said valve assemblage, said valve assemblage comprising a body portion slidably mounted in a bore in said casing and removable therefrom as a unit by the use of said screwthread means, inlet valve means mounted Within the limits of said body portion in an inlet communication from said strainer assemblage to said pumping piston, discharge valve means mounted in said body portion in a discharge communication from said pumping piston to said friction parts, and release valve means mounted in said body portion in a communication from said pumping piston to said crank chamber.

7. In an air compressor having an air compressing piston, a crank chamber, an oil pump having an oil pumping piston for lubricating friction parts of said compressor with oil from said crank chamber, a valve assemblage for controlling the flow of oil to and from said pumping piston and also the pressure of oil supplied from said pumping piston, a crank shaft operatively connected to said piston for reciprocation thereby, said crank chamber having an opening in its side adjacent said oil pump, a removable cover plate effecting closure of said opening, a strainer assemblage for filtering and conducting oil from said crank chamber to said valve assemblage, and screw-thread means for mounting said strainer in said crank chamber in registration with said valve assemblage, said valve assemblage comprising a body portion slidably mounted in a bore in said pump open to said crank chamber and removable therefrom by the use of said screw-thread means lengthwise from said pump and sidewise from said crank chamber through said opening, inlet valve means mounted Within the limits of said body portion and operative in re sponse to suction by said pump piston to connect oil in said'crank chamber to said pumping piston, and discharge valve means mounted within the limits of said body portion and operative in response to oil pressure exerted by said pumping piston to connect said pumping piston to said friction parts.

8. In an air compressor having an air compressing piston, a crank chamber, an oil pump having an oil pumping piston for lubricating friction parts of said compressor with oil from said crank chamber, a valve: assemblage for controlling the flow of oil to and from said pumping piston and also the pressure of oil supplied from said pumping piston, a crank shaft operatively connected to said piston for reciprocation thereby, said crank chamber having an opening in its side adjacent said oil pump, a removable cover plate effecting closure of said opening, a strainer assemblage for filtering and conducting oil from said crank chamber to said valve assemblage, and screwthread means for mounting said strainer in said crank chamber in registration with said valve assemblage, said valve assemblage comprising a body portion slidably mounted in a bore in said pump open to said crank chamber and removable therefrom by the use of said screw-thread means lengthwise from said pump and sidewise from said crank chamber through said opening, inlet valve means mounted within the limits of said body portion and operative in response to suction by said pump piston to connect oil in said crank chamber to said pumping piston, discharge valve means mounted within the limits of said body portion and operative in response to oil pressure exerted by said pumping piston to connect said pumping piston to said friction parts, and release valve means mounted within the limits of said body portion operative in response to an increase in pressure of lubricant flowing from said pumping piston above a cer tain degree to connect said piston to said crank chamber.

9. A lubricating pump assemblage for a compressor or the like of the type comprising a casing having an oil carrying crank chamber and a crank shaft extending through said chamber and supported in bearings in opposite end walls of said casing, said pump comprising in combination with said casing and crank shaft, a pump housing rockably mounted in said casing in a bearing disposed parallel to but to one side of said crank shaft bearings and having a piston bore at right angles to said bearings and a valve assemblage bore parallel to said bearing and open at one end to said crank chamber, a piston in said piston bore reciprocable by rotation of said crank shaft, an inlet, discharge and relief valve assemblage for said piston slidably mounted in said valve assemblage bore, and a cover removably secured over an opening in a side Wall of said casing for providing access to said crank chamber for applying and removing said valve assemblage to and from its bore through the open end thereof.

10. A lubricating pump assemblage for a compressor or 7 the like vi the ype o p s a i having an Oil sat ying c ank chamb r a a cran h ft e ng thmugli said shamber and s pper e in be i P- pos end a ls f a c i g; said pump comprising n eog binatign with said casing and crank shaft, a casing hearing at one side of said crank shaft bearings and arranged wi h ts axi p le th re o, a ubr t p mp housing rockably mounted in said casing bearing and having a valve assemblage bo 'e arranged in coaxial relation t9 said as ng bearing and p a n n to s crank chambe; and also having a piston bore arranged at right angles to s id eari g .a p s on ns id P n o e pr able by eta ion' said ra k s ft, an inlet, d sha e an el ef valve assemb a r said pi n li blyfmeuntecl i sa al ass m lag bore emo abl h eu h the open end ther f a ner nted over of sa d bolt, sai e mpx r ea having n Opening in a side wall thereof providing access to the open end of said valve assemblage bore, and a cover removably se u d to aid asing ov r s d pen ng- References Cited in the file of this patent UNITED STATES PATENTS 1,781,416 Sundstrand Nov. 11, 1930 2,017,684 Crittenden Oct. 15, 1935 2,065,204 Aikman Dec. 22, 1936

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