US3583371A

US3583371A - Pump for rotary machine

Info

Publication number: US3583371A
Application number: US813891A
Authority: US
Inventors: Robert W King
Original assignee: Copeland Refrigeration Corp
Current assignee: Copeland Refrigeration Corp
Priority date: 1969-04-07
Filing date: 1969-04-07
Publication date: 1971-06-08
Anticipated expiration: 1988-06-08

Abstract

An oil pump and lubricating system for a rotary piston machine such as a four cycle internal combustion engine. The timing gears that correlate the relative rotation of the rotor and outer housing are used as an oil pump for forcing lubricating oil to certain bearing surfaces of the engine. In an embodiment of the invention a bypass is provided in the pump to prevent excess oil from being delivered to the lubricated surface of the engine. In this embodiment, a valve is provided that closes off the bypass when the engine is not being operated and which opens when the engine is restarted for insuring the immediate delivery of oil to the lubricated surfaces.

Description

United States Patent [72] inventor Robert W. King Sidney, Ohio [21] Appl. No. 813,891 [22] Filed Apr. 7, 1969 [45] Patented June 8, 1971 [73] Assignee Copeland Refrigeration Corporation [54] PUMP FOR ROTARY MACHINE 25 Claims, 9 Drawing Figs.

[52] US. Cl 123/8.45, 417/310, 418/61, 418/87, 418/88 [51] int. Cl ..F02b 53/00, FOlc 1/08 [50] Field of Search 123/8 LL, 8 GOK, 8 CC, 8 PH, 8.45; 103/130; 230/145; 91/56; 418/61, 87, 88; 417/310 [56] References Cited UNITED STATES PATENTS 969,478 9/1910 Humphreys 103/130 Primary Examiner-Allan D. Hermann Attorney-Harness, Dickey & Pierce ABSTRACT: An oil pump and lubricating system for a rotary piston machine such as a four cycle internal combustion engine. The timing gears that correlate the relative rotation of the rotor and outer housing are used as an oil pump for forcing lubricating oil to certain bearing surfaces of the engine. In an embodiment of the invention a bypass is provided in the pump to prevent excess oil from being delivered to the lubricated surface of the engine. In this embodiment, a valve is provided that closes off the bypass when the engine is not being operated and which opens when the engine is restarted for insuring the immediate delivery of oil to the lubricated surfaces.

PATENTEnJun 8l97l 3583371 sum u 0F 5 PUMP FOR ROTARY MACHINE BACKGROUND OF THE INVENTION This invention relates to a pump for a rotary machine and more particularly to a lubricant pump for a rotating piston machine.

Various types of rotary machines have been proposed wherein a piston and outer housing undergo relative rotation and cooperate to define at least one chamber the volume of which varies upon such relative rotation. Although these machines generally have the common advantage that they have fewer moving parts than comparable reciprocating piston machines, the previously proposed machines of this type require additional auxiliary mechanisms which increase their complexity and cost. For example, the moving parts of this type of mechanism, as all mechanisms, require lubrication and it has been common practice to employ a separate lubricant pump for lubricating these parts. When these mechanisms are used as internal combustion engines, their high and localized heat generation has necessitated the use of the lubricant for a considerable portion of the cooling. Thus, high volumes of lubricant are required necessitating large oil pumps.

It is, therefore, a principal object of this invention to provide an improved pump for a rotary machine.

It is another object to provide an improved oil pump for a rotating piston machine.

It is a further object of this invention to provide an oil pump for a rotary machine that utilizes some of the existing components of the machine, thus simplifying the overall construction.

In many types of pumps, the pump output is greater than the amount of fluid required. For this and other reasons, it has been proposed to provide a bypass for returning a portion of the fluid pumped back to the inlet side. The use of such a bypass arrangement is well known in positive displacement gear-type pumps. Under some conditions, such as at start up, the bypassing of the pumped fluid is either unnecessary or is undesirable. For example, an open bypass passage might require priming of the pump to start it. For this reason, it has been proposed to valve such bypass passages. The valves heretofore proposed for this purpose are relatively expensive, however. It is, therefore, another object of this invention to provide an improved simplified bypass valve for a positive displacement pump.

It is a further object of this invention to provide an improved low cost bypass valve for a gear-type pump.

SUMMARY OF THE INVENTION A lubricant pump embodying this invention is particularly adapted for use in a rotary mechanism having first and second relatively movable members cooperating to define at least one chamber of a volume that varies as the members undergo such relative movement. Timing gear means are provided for interrelating the relative movement between the members. The timing gear means comprises at least two timing gears having intermeshing teeth. The lubricant pumping means includes the timing gears and functions to deliver lubricant under pressure to the parts of the machine for lubricating the parts. The pumping means includes lubricant conduit means for delivering lubricant into the spaces between the teeth of the timing gears when the teeth move out of mesh and for receiving lubricant trapped between the teeth as the teeth move into mesh thereby using the meshing of the timing gear teeth as a means for pressurizing and pumping the lubricant.

Another feature of the invention is adapted to be embodied in a gear pump comprised of an internal gear and an external gear enmeshed with the internal gear and wherein the gears are supported for relative planetary movement. A fluid inlet is defined in the area where the gears are moving out of mesh for drawing a fluid into that area and a fluid outlet is defined in the area where the gears are moving into mesh for receiving the pumped fluid. Means are interposed between the gears in the area where they are out of mesh and between the inlet and outlet areas for precluding any substantial back flow of fluid from the outlet to the inlet. A bypass passage extends between the fluid outlet and the fluid inlet for returning an excess of fluid pumped to the inlet. Valve means are provided for controlling the flow through the bypass passage. The valve means is movable between an opened position wherein flow is permitted through the bypass passage and a closed position wherein fluid is substantially precluded. The valve means is engageable with at least one of the gears and responsive to relative rotation for tending to move the valve means to its closed position. The valve means has a portion exposed to the fluid pressure in the fluid outlet area for moving the valve means to its opened position when sufficient pressure is generated in the outlet area.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of a rotary piston internal combustion engine embodying this invention with certain of the auxiliary components of the engine removed.

FIG. 2 is a side elevational view of the engine shown in FIG. 1.

FIG. 3 is an enlarged cross-sectional view taken along the line 3-3 of FIG. 2 showing the rotor and its coaction with the housing.

FIG. 4 is a further enlarged cross-sectional view, with parts broken away, taken generally along the line 4-4 of FIG. 3 and shows the piston rotated from the position in FIG. 3.

FIG. 5 is an even further enlarged cross-sectional view taken along the line 5-5 of FIG. 4.

FIG. 6 is an enlarged cross-sectional view taken along the line 6-6 of FIG. 4.

FIG. 7 is an enlarged view taken along the line 7-7 of FIG. 4 with a portion broken away.

FIG. 8 is a cross-sectional view, in part similar to FIG. 5, and shows another embodiment of the invention.

FIG. 9 is a cross-sectional view taken along the line 9-9 of FIG. 8.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the invention is described in conjunction with a rotating piston, four cycle, internal combustion engine, the invention is susceptible of use in other rotating machines and particularly those in which timing gears are embodied for correlating the motion between two relatively movable members, as will become more apparent as this description proceeds. An engine embodying this invention is identified generally by the reference numeral 11 and is depicted in FIGS. 1 and 2 with certain supporting equipment such as a fuel tank, carburetor and muffler removed for sake of illustration. The engine 11 includes an outer housing assembly 12 in which an output shaft 13 is supported for rotation. The engine 11 is designed so that the output shaft 13 may be disposed vertically, as shown in the drawings, or horizontally. To assist in the vertical mounting, mounting bosses or lugs 14 are formed upon the lower portion of the outer housing assembly 12 and particularly at the base of an oil sump casting, indicated generally by the reference numeral 15. Side mounting bosses 16 are also formed in the outer housing 12 and sump casting 15 so that the engine 11 may be mounted with the output shaft 13 extending in a horizontal direction.

Referring now primarily to FIGS. 3 and 4, the outer housing 12 is formed with a cavity 17 in which a rotor, indicated generally by the reference numeral 18, is supported. The opposite ends of cavity 17 are closed by upper and lower end walls 19 and 21, which end walls are affixed to the outer housing 12 in any known manner. The rotor 18 has a shape which, as will become more apparent as this description proceeds, generally resembles a triangle having apex portions 22, 23 and 24. Apex seals 25, 26 and 27 are carried in complementary grooves formed in the apex portions 22, 23 and 24 and engage the inner surface of the outer housing 12 that defines the cavity 17 to divide the cavity 17 into three chambers 28, 29 and 31. Compression and oil seals 32 and 33 are received in circular grooves formed in opposite faces of the rotor 18 and engage the upper and lower face plates 19 and 21, respectively, to complete the sealing of the chambers 28, 29 and 31.

The rotor 18 is formed with a cylindrical bore 34 that forms a bearing surface which engages a complementary bearing surface 35 formed on an eccentric 36. The eccentric 36 is, in turn, affixed to the output shaft 13 with its surface 35 being eccentrically disposed with respect to the axis of rotation of the output shaft 13. The output shaft 13 is journaled in spaced cylindrical bores 37 and 38 formed by the top plate 19 and oil sump casting 15, respectively.

Referring now additionally to FIGS. through 7, adjacent the bottom end plate 21, rotor 18 is formed with an internal gear 41. The gear 41, which is formed adjacent one end of the bearing surface 34, engages an external gear 42 that is fixed relative to the bottom end plate 21 and, in the depicted embodiment, is formed integrally with this end plate. As is well known with this type of mechanism, the gears 41 and 42 act as timing gears to relate the movement of the rotor 18 relative to the outer housing 12 as these elements undergo relative rotation. During such relative rotation, the rotor apex seals 25, 26 and 27 sweep across the surface 17 of the housing 12 and the volumes of the chambers 28, 29 and 31 alternately increase and decrease in volume.

In this type of mechanism, it has been proposed to embody a generated shape for the cavity 17 with the rotor 18 having an external configuration that constitutes the inner envelope of this generated shape. The use of such geometry is described in the British Pat. to Millard, No. 583,035, accepted Dec. 5, I946. The shape of the surface 17 is, however, not a truly generated shape since such true shapes are difficult to form. As is noted in the British Millard patent, the shape of the cavity in the outer housing is generated by a point on a line that extends tangentially to an eccentric circle and which revolves around this circle. It has been found that if the ratio of the length or radius of the generating line to the radius of the eccentric circle is approximately equal to 8.5, the generated shape may be closely approximated by an oval shape. Such a configuration, therefore, is incorporated in the disclosed engme.

The outer housing 12 is formed with an exhaust port 45 from which an exhaust flange 46 extends to accommodate a muffler (not shown). One of the end walls, for example the upper end wall 19, is formed with an inlet port 47 through which a combustible mixture is delivered in any known manner. For example, the mixture may be introduced through the port 47 in a manner as disclosed in my copending patent application entitled Air Cooling System for a Rotary Machine, Ser. No. 813,891, filed Apr. 7, 1969, assigned to the assignee of this invention. As is well known with this type of mechanism, relative rotation of the rotor 18 with respect to the outer housing 12 will cause a charge to be sequentially delivered to the chambers 28, 29 and 31, subsequently compressed for firing by a spark plug 48, permitted to expand driving the output shaft 13 and eventually exhausted through the exhaust port 45. As is well known, such mechanisms generate a rather substantial amount of heat during their operation. The thus generated heat is dissipated in the disclosed engine 11 by a form of air cooling incorporating the formation of fins 51 on the outer housing 12 and through intake charge cooling as disclosed in my aforenoted copending patent application. In addition, the lubricant contained within the sump is employed as a cooling medium in part as well as a lubricant, the lubrication being achieved in the manner now to be described.

Referring specifically to FIG. 4, the sump 15 is fixed to the lower plate 21 in any known manner and a plurality of cooling fins 52 formed on the lower plate 21 extend into the sump casting and partially the lubricant cavity 53 formed thereby. Upstanding projections 54 formed on the base of the sump casting 15 serve to transmit heat from the oil in the sump cavity 53 to the atmosphere. The meshing of the timing gears 41 and 42 is utilized for pumping lubricant from the sump to at least some of the bearing surfaces. For this purpose, an inlet conduit 55 depends beneath the liquid level in the sump cavity 53. A fitting 56 at one end of the conduit 55 is received in a tapped hole 57 formed in a central boss 58 of the sump 15. Intersecting passages 59 and 61 carry the lubricant from the conduit 55 upwardly through the boss 58 to an annular recess 62 formed at the upper end of the boss 58 around the upper termination of the cylindrical bore 38.

Referring now additionally to FIGS. 5 through 7, the recess 62 is in communication with a relieved axially extending passage 63 formed adjacent a bore 64 formed in the end plate 21, which bore also journals the output shaft 13. The axially extending passage 63 terminates adjacent a second relieved area 65 formed at the opposite end of the bore 64. This relieved area is formed adjacent a generally relieved end surface 66 of the eccentric 36. A pump inlet passage 67 is formed in the surface 66 and extends outwardly from the main portion of the output shaft 13 to a point that is disposed in an area where the gears 41 and 42 are out of mesh and where the gears 41 and 42 are moving away from each other. This condition exists, as shown in FIG. 5, when the rotor 18 and eccentric 36 are turning in a counterclockwise direction relative to the outer housing 12. Thus, the movement of the teeth of the gears 41 and 42 away from each other causes a low pressure area so that lubricant will be drawn through the conduit 55, passages 59, 61, annular groove 62, recess 63, annular groove 65 and inlet port 67 from the sump cavity 53.

A generally crescent-shaped section 69 formed integrally with the eccentric 36 extends between the teeth of the gears 41 and 42 in the area where these gears are out of mesh and adjacent to the inlet passage 67. The section 69 is juxtaposed to the crests of the teeth of the gears 41 and 42 to provide an effective seal in this area and has a height substantially the same as the face width of the gears 41 and 42. The oil drawn into the space between the teeth of the gears 41 and 42 will be carried around between the teeth and past the crescent shaped section 69 into a pumping chamber 71 formed in the area adjacent the area where the teeth of the gears 41 and 42 are in mesh. The pumping chamber 71 lies on a side of the axis of shaft 13 diametrically opposite to the inlet passage 67. The pumping chamber 71 lies in an area where the timing gears 41 and 42 are moving into mesh. Thus, the lubricant trapped in this chamber will be pressurized by this relative movement of the timing gears 41 and 42.

A pair of discharge ports 72 and 73 extend into the pumping chamber 71. The ports 72 and 73 are formed at the termination of the pressure passages 74 and 75, respectively, formed in the eccentric 36. The other end of the passage 75 terminates in the outer surface 35 of the eccentric 36 so that lubricant forced through this passage will lubricate the

surfaces

34 and 35 of the rotor 18 and eccentric 36. The passage 74 extends the length of the eccentric 36 and terminates at its other end at a relief 78 formed in the end plate 19 adjacent the cylindrical bore 37. The lubricant delivered to this area will pass into the clearance between the bore 37 and shaft 13, which clearance is exaggerated in FIG. 4 for the sake of illustration, to lubricate these parts. Any known type of seal 79 is provided at the upper end of the bore 37 in a counterbore 81 to preclude against the escape of lubricant. Lubricant is returned to the sump cavity 13 from the counterbore 81 by means of a conduit 82.

A vent passage 83 is provided in the sump casting 15 at a point above the lubricant level. This vent passage provides for the relief of any pressure build up which may occur in the sump. If desired, the vent 83 may be connected by means of a conduit (not shown) or induction system so that the sump gases will not be discharged directly to the atmosphere.

The portion of the output shaft 13 that is journaled in the bore 38 is lubricated by means of a pair of helical passages 84 and 85 formed either in the shaft 13 or in the bore 38, the former construction being illustrated in the drawings. The

passage 84 is of such a hand that lubricant will be conveyed from the recess 62 axially down the shaft 38 to a point adjacent a seal 86. The groove 85 is of an opposite hand from the groove 84 and returns the oil from adjacent the seal 86 along the length of the shaft 13..

In the previous embodiment, substantially all of the lubricant delivered by the pump was transmitted to the lubricated parts of the engine. Since the ratio between the gears 41 and 42 is fixed by the geometry of the engine and the size of these gears is also dictated generally by the engine, it may be found that this type of pump will move more oil than is required for the lubricating and cooling functions. Although it would be possible to provide a simple bypass passage for returning the excess lubricant to the inlet side of the pump or the sump, an open bypass passage might tend to cause the pump to be drained of lubricant when the engine is shut down resulting in lack of lubrication when the engine is again started. In addition, in such an instance it might be necessary to prime the pump in order for it to operate.

FIGS. 8 and 9 show an embodiment wherein a simplified valve bypass arrangement is employed. Although this bypass and valve arrangement is described in conjunction with a machine of the type previously described, it should be readily apparent that this arrangement may be used in conjunction with other types of pumps and particularly with an internal-external gear-type pump.

Referring now in detail to FIGS. 8 and 9, P16. 8 is a crosssectional view which may be considered to be taken through the same plane as FIG. 5. As has been noted, this embodiment is particularly adapted for use in a mechanism of the type previously described and, for this reason, the mechanism as a will not be described again and identical parts have been identified by the same reference numerals as used in the description of the preceeding embodiment. In this embodiment, the internal gear 41 is formed on the rotor 18 and meshes with an external gear 42 that is fixed to or formed integrally with the end plate and which encircles the output shaft 13. The pump inlet passage 67 is disposed in an area where the gears 41 and 42 are out of mesh and where these gears are moving away from each other. The eccentric 36 is formed with a generally crescent-shaped section 69 that extends circumferentially around from the inlet passage 67 to the discharge ports 72 and 73. This much of the mechanism is the same as in the previously described embodiment and its operation will not be repeated.

The inner surface of the crescent-shaped section 69 adjacent the ports 72 and 73 is formed with a generally circumferentially extending cutout 101 that extends substantially the full depth of the section 69 and which opens into the area where the ports 72 and 73 are disposed. The eccentric 36 is formed with a bypass passage 102 that extends adjacent the cutout 101 and passes radially inwardly toward and terminates at the annular groove 65.

A generally arcuately shaped bypass valve member 103 is received in the cutout 101 and is shorter in length than this cutout. The valve member 103 has an upstanding projection 104 that is received in a smaller and narrower cutout 105 formed in the crescent-shaped section 69. The valve member 103 is also in frictional contact with the teeth of the external gear 42.

In operation, when the engine 11 is running, the pressure generated by the action of the pump will be exerted against an end face 106 of the valve member 103 causing it to move to an opened position as shown in FIG. 8. This pressure must overcome the viscous and frictional forces acting on the valve member 103 tending to cause it to move in an opposite or closed direction. The reason for these frictional forces is that the eccentric 36 is rotating in the direction of the arrow 107 while the rotor 18 is also rotating in this direction, as indicated by the arrow 108. Of course, the eccentric 36 is rotating at a slower speed than the rotor 18 as is well known with this type of engine considering the gear 42 as being fixed. Due to this relative rotation, the valve member 103 will tend to move to a closed position, as has been previously noted. The pressure acting on the face 106 is, however, sufficient to cause this valve to be opened so that a certain portion of the oil is bypassed through the recess 101 and passage 102 back to the annular groove 65. This excess oil is, therefore, available at the pump inlet side.

When the engine is stopped, and pressure on the outlet side of the pump will decrease even though the rotor 18 and eccen tric 36 continue to rotate. At a point shortly before the engine ceases rotation, the valve member 103 will be slid to its closed position as shown in the dotted line view of FIG. 8 thus precluding the bypassing of oil when the engine is restarted. In addition, the closing of this bypass passage will insure that the oil will not be drained from the pump through the bypass passage. As soon as the engine is started and sufficient pressure is developed by the pump, the valve 103 will again open.

The described lubricant pump is capable of delivering a high volume of lubricant to the engine and thus assist in its cooling. Although the lubricant pump has been described in conjunction with a machine wherein the outer housing is stationary and the rotor rotates, it should be readily apparent that, as is typical with this type of machine, both the outer housing and the rotor can undergo relative rotation or the rotor could be fixed and the outer housing can rotate.

What I claim is:

l. A rotary machine having first and second relatively movable members having interengaging surfaces cooperating to define at least one chamber of varying volume as said members undergo such relative movement, timing gear means for interrelating the relative movement between said members, said timing gear means comprising at least two timing gears having intermeshing teeth, and lubricant pumping means including said timing gears for delivering lubricant under pressure to parts of said machine for lubricating such parts, said lubricant pumping means comprising lubricant conduit means for delivering lubricant into the spaces between the teeth of said timing gears when said teeth are out of mesh and for receiving lubricant trapped between said teeth as said teeth move into mesh, said lubricant pumping means thereby using the meshing of said timing gear teeth as a means for pressurizing and pumping the lubricant.

2. A rotary machine as set forth in claim 1 further including bypass means for returning a portion of the pressurized and pumped lubricant directly back to the input side of said lubricant pumping means for limiting the amount of lubricant delivered to the lubricated parts.

3. A rotary machine as set forth in claim 2 further including valve means in said bypass means for closing off said bypass means when the members cease relative movement and for opening said bypass means when said members commence relative movement.

4. A rotary machine having first and second relatively movable members cooperating to define at least one chamber of varyingvolume as said members undergo such relative movement, timing gear means for interrelating the relative movement between said members, said timing gear means comprising at least two timing gears having intermeshing teeth, and lubricant pumping means including said timing gears for delivering lubricant under pressure to parts of said machine for lubricating such parts, said lubricant pumping means comprising lubricant conduit means for delivering lubricant into the spaces between the teeth of said timing gears when said teeth are out of mesh and for receiving lubricant trapped between said teeth as said teeth move into mesh, said lubricant pumping means thereby using the meshing of said timing gear teeth as a means for pressurizing and pumping the lubricant, bypass means for returning a portion of the pressurized and pumped lubricant directly back to the input side of said lubricant pumping means for limiting the amount of lubricant delivered to the lubricated parts, and valve means in said bypass means for closing off said bypass means when the members cease relative movement and for opening said bypass means when said members commence relative movement, said valve means is frictionally engaged with at least one of said timing gears for exerting a closing force upon said valve means, a portion of said valve means being exposed to the pressure on the outlet side of the lubricant pumping means for opening said valvemeans when said lubricant pumping means generates sufficient pressure.

5. A rotary machine having first and second relatively movable members cooperating to define at least one chamber of varying volume as said members undergo such relative movement, timing gear means for interrelating the relative movement between said members, said timing gear means comprising at least two timing gears having intermeshing teeth, said rotary machine comprising an internal combustion engine, means for introducing a charge to said chamber, means for firing the charge within said chamber, and means for exhausting the burnt charge from said chamber, and lubricant pumping means including said timing gears for delivering lubricant under pressure to parts of said machine for lubricating such parts, said lubricant pumping means comprising lubricant conduit means for delivering lubricant into the spaces between the teeth of said timing gears when said teeth are out of mesh and for receiving lubricant trapped between said teeth as said teeth move into mesh, said lubricant pumping means thereby using the meshing of said timing gear teeth as a means for pressurizing and pumping the lubricant.

6. A rotary machine as set forth in claim 1 wherein the first relatively movable member comprises an outer housing defining a cavity and the second member comprises a rotor received within the cavity.

7. A rotary machine as set forth in claim 6 wherein the rotor comprises a lobed rotor that substantially traces the cavity of the outer housing and which defines a plurality of variable volume chambers with the outer housing.

8. A rotary machine as set forth in claim 7 wherein the rotary machine comprises an internal combustion engine and further includes means for successively introducing a charge to the chambers, means for firing the charge within the chambers and means for exhausting the burnt charge from the chambers.

9. A rotary machine as set forth in claim 7 wherein the traced path of the cavity has a substantially oval configuration.

10. A rotary machine as set forth in claim 7 wherein the tim ing gears comprise an external gear and an internal gear.

11. In a rotary machine having an outer housing defining a cavity, a rotor supported within said cavity and having means thereon engaging said outer housing to define therewith at least one chamber, means for supporting said outer housing and said rotor for relative movement whereby said chamber alternately contracts and expands in volume, said rotor performing a planetating motion relative to said outer housing upon said relative movement, and timing gears from interrelating such relative movement of said outer housing and said rotor, said timing gear means comprising an internal gear fixed relative to said rotor and an external gear fixed relative to said outer housing and intermeshing with said internal gear, the improvement comprising means for employing the intermeshing action of said timing gears for a pump for delivering a fluid to components of the machine, said last named means comprising a fluid inlet passage communicating with a space between said timing gears where said gears are moving out of mesh for introducing a fluid into said space and between the teeth of said timing gears, and a fluid outlet passage communicating with an area where said timing gears are approaching meshing relation for receiving fluid-under pressure trapped between the teeth of said gears as said gears move into mesh and for transmitting the pressurized fluid to the machine component.

12. A rotary machine as set forth in claim 11 wherein the fluid pumped comprises a lubricant, the fluid outlet passage including conduit means for extending to parts of the machine to be lubricated.

13. A rotary machine as set forth in claim 11 wherein the machine further includes an eccentric for supporting the rotor and rotatable about an axis eccentrically disposed with respect to said rotor, the fluid inlet passage being in communication with the space between the ti ing gears on one side of a plane containing the axis of said gears and the point where said gears are in mesh, the fluid outlet passage communicating with the space between the gears on the other side of said plane, and means on said eccentric extending into the area wherein said timing gears are out of mesh and between said inlet and outlet passages for substantially precluding back flow between said passages.

M. A rotary machine as set forth in claim 13 further including a bypass passage interconnecting the fluid outlet passage with the fluid inlet passage for returning a portion of the fluid pumped back to the fluid inlet passage.

15. A rotary machine as set forth in claim 14 further including valve means for controlling the flow through the bypass passage.

16. A rotary machine as set forth in claim 15 wherein the valve means comprises a movable valve member carried by the eccentric and engageable with the external gear for tending to close said valve means upon relative rotation of said external gear and said eccentric, the fluid pressure generated by the pump acting on said valve member in a direction for tending to open said valve member.

17. A lubricating system for a rotary machine having an outer housing defining a cavity, a rotor received in said cavity, means on said rotor engaging said outer housing for dividing said cavity into at least two chambers, an eccentric shaft journaled in said outer housing and extending through said cavity, said rotor and said eccentric shaft having cooperating bearing surfaces defining an axis offset from the axis of rotation of said eccentric shaft for supporting said rotor for rotation relative to said eccentric shaft about the axis of said bearing surfaces and for relative rotation of said outer housing and said rotor, an internal gear affixed to said rotor, an external gear affixed to said outer housing and enmeshed with said internal gear for correlating the relative movement, a fluid inlet passage formed at least in part in said eccentric shaft in communication with the area where said internal gear and said external gear are out of mesh and on one side of a plane containing the axes of said gears and the point where said gears are in mesh, a fluid outlet passage formed in said eccentric shaft on the other side of said plane, said inlet passage opening into the side of said plane where said gears are moving out of mesh and away from each other for drawing fluid into the space between the teeth of said gears, said outlet passage being located on the side of said plane where said gears are moving into mesh for receiving fluid under pressure from between said teeth, and means for substantially precluding flow from said outlet passage to said inlet passage.

1%. A lubricating system as set forth in claim 17 wherein the last named means comprises a crescent-shaped member fixed to the eccentric shaft and extending into the area where the gears are out of mesh.

19. A lubricating system as set forth in claim 17 wherein the internal gear is formed adjacent one end face of the rotor and the external gear is formed on an end wall of the outer housmg.

20. A lubricating system as set forth in claim 18 wherein the fluid outlet passage extends to the bearing surfaces of the eccentric shaft and the rotor for delivering lubricant to said bearing surfaces.

21. A gear pump comprising an internal gear, an external gear enmeshed with said internal gear, means for supporting said gears for relative planetary movement, means defining a fluid inlet to the area where said gears are moving out of mesh for drawing a fluid into said area, means defining a fluid outlet in the area where said gears are moving into mesh for receiving fluid under pressure, means interposed between said gears in the area where said gears are out of mesh and between said inlet and said outlet areas for precluding any substantial back flow of fluid from said fluid outlet and said fluid inlet, a bypass passage extending between said fluid outlet and said fluid inlet for returning a portion of the fluid under pressure from said fluid outlet area to said fluid inlet area, valve means for controlling the flow through said bypass passage, said valve means being movable between an opened position wherein flow through said bypass passage is permitted and a closed position wherein flow through said bypass passage is substantially restricted, said valve means being engageable with one of said gears and responsive to relative movement between said gears for tending to move said valve means to its closed position, said valve means having an area exposed to the pressure in said fluid outlet area for moving said valve means to its opened position against the closing forces thereon when sufficient fluid pressure is generated in said fluid outlet area.

22. A gear pump as set forth in claim 21 wherein the means interposed between the gears comprises a crescent-shaped segment fixed to an eccentric, the fluid inlet and the fluid outlet being defined by said eccentric adjacent the respective ends of said crescent-shaped segment, said valve means being carried by said segment and engaged with the internal gear.

23. A pump comprising a plurality of members supported for relative movement, said members defining at least one chamber adapted to vary in volume for effecting a pumping action, an inlet to said chamber, an outlet from said chamber, a bypass passage for bypassing at least a portion of the fluid displaced from said chamber by said pumping action, and a valve for controlling the flow through said bypass passage, said valve comprising a valve element engageable with at least one of said members and responsive to relative movement of said one member for tending to move said valve element to its closed position, said valve element having an area exposed to the pressure of said pumping action for moving said valve element to its opened position against the closing forces thereon when sufficient pressure is generated.

24. A pump as set forth in claim 23 wherein at least certain of the members comprise interengaging lobed members.

25. A pump as set forth in claim 24 wherein the valve element is engaged with one of the lobed members.

Claims

1. A rotary machine having first and second relatively movable members having interengaging surfaces cooperating to define at least one chamber of varying volume as said members undergo such relative movement, timing gear means for interrelating the relative movement between said members, said timing gear means comprising at least two timing gears having intermeshing teeth, and lubricant pumping means including said timing gears for delivering lubricant under pressure to parts of said machine for lubricating such parts, said lubricant pumping means comprising lubricant conduit means for delivering lubricant into the spaces between the teeth of said timing gears when said teeth are out of mesh and for receiving lubricant trapped between said teeth as said teeth move into mesh, said lubricant pumping means thereby using the meshing of said timing gear teeth as a means for pressurizing and pumping the lubricant.

4. A rotary machine having first and second relatively movable members cooperating to define at least one chamber of varying volume as said members undergo such relative movement, timing gear means for interrelating the relative movement between said members, said timing gear means comprising at least two timing gears having intermeshing teeth, and lubricant pumping means including said timing gears for delivering lubricant under pressure to parts of said machine for lubricating such parts, said lubricant pumping means comprising lubricant conduit means for delivering lubricant into the spaces between the teeth of said timing gears when said teeth are out of mesh and for receiving lubricant trapped between said teeth as said teeth move into mesh, said lubricant pumping means thereby using the meshing of said timing gear teeth as a means for pressurizing and pumping the lubricant, bypass means for returning a portion of the pressurized and pumped lubricant directly back to the input side of said lubricant pumping means for limiting the amount of lubricant delivered to the lubricated parts, and valve means in said bypass means for closing off said bypass means when the members cease relative movement and for opening said bypass means when said members commence relative movement, said valve means is frictionally engaged with at least one of said timing gears for exerting a closing force upon said valve means, a portion of said valve means being exposed to the pressure on the outlet side of the lubricant pumping means for opening said valve means when said lubricant pumping means generates sufficient pressure.

10. A rotary machine as set forth in claim 7 wherein the timing gears comprise an external gear and an internal gear.

11. In a rotary machine having an outer housing defining a cavity, a rotor supported within said cavity and having means thereon engaging said outer housing to define therewith at least one chamber, means for supporting said outer housing and said rotor for relative movement whereby said chamber alternately contracts and expands in volume, said rotor performing a planetating motion relative to said outer housing upon said relative movement, and timing gears from interrelating such relative movement of said outer housing and said rotor, said timing gear means comprising an internal gear fixed relative to said rotor and an external gear fixed relative to said outer housing and intermeshing with said internal gear, the improvement comprising means for employing the intermeshing action of said timing gears for a pump for delivering a fluid to components of the machine, said last named means comprising a fluid inlet passage communicating with a space between said timing gears where said gears are moving out of mesh for introducing a fluid into said space and between the teeth of said timing gears, and a fluid outlet passage communicating with an area where said timing gears are approaching meshing relation for receiving fluid under pressure trapped between the teeth of said gears as said gears move into mesh and for transmitting the pressurized fluid to the machine component.

13. A rotary machine as set forth in claim 11 wherein the machine further includes an eccentric for supporting the rotor and rotatable about an axis eccentrically disposed with respect to said rotor, the fluid inlet passage being in communication with the space between the timing gears on one side of a plane containing the axis of said gears and the point where said gears are in mesh, the fluid outlet passage communicating with the space between the gears on the other side of said plane, and means on said eccentric extending into the area wherein said timing gears are out of mesh and between said inlet and outlet passages for substantially precluding back flow between said passages.

14. A rotary machine as set forth in claim 13 further including a bypass passage interconnecting the fluid outlet passage with the fluid inlet passage for returning a portion of the fluid pumped back to the fluid inlet passage.

18. A lubricating system as set forth in claim 17 wherein the last named means comprises a crescent-shaped member fixed to the eccentric shaft and extending into the area where the gears are out of mesh.

19. A lubricating system as set forth in claim 17 wherein the internal gear is formed adjacent one end face of the rotor and the external gear is formed on an end wall of the outer housing.