US2653549A - Eccentric pump - Google Patents

Description

Sept. 29, 1953 L. F. KNIGHT ECCENTRIC PUMP 3 Sheets-Sheet 1 Filed March 25, 1949 IIIIIIIIIIIIIIII Ta .SUMP

ECCENTRIC PUMP Filed March 23, 1949 3 Sheets-Sheet 2 Jivenior Zoe/v5 f7 kmal/ L. F. KNIGHT ECCENTRIC PUMP Sept. 29, 1953 Filed March 23, 1949 3 Sheets-Sheet 3 Patented Sept. 29, 1953 UNITED ECCENTRIC PUMP Lorne F. Knight, Toronto, Ontario, Canada, assignor to Massey-Harris Co. Ltd., Toronto, On-

tario, Canada Application March 23, 1949, Serial No. 83,077

1 Claim.

This invention relates to improvements in eccentric pumps.

Various types of eccentric pump are known and attempts have been made to provide a pumping device of this class wherein the output is delivered through the rotor shaft. In such prior types of pump, however, difliculties are encountered in manufacture in providing the necessary tolerances to insure against leakage, thus resulting in high costs in production. Further with prior pumps of this class it has been necessary to float the outer casing so that axial movement of the rotor shaft would not cause binding of the pump components. Usually a disadvantage of this character has previousl precluded the use of a pump of this class for many purposes.

In oil feeding systems in general for various types of engines such as gasoline and diesel engines, it has been necessary to provide separate pumps for supplying oil to various points of the engine at different pressures.

By way of distinction the present invention has for its object the provision of a pump of the class referred to which requires only rough tolerance machining with the exception of the machining operations relevant to the structure directly associated with the pumping action.

Another object of the invention is to provide an eccentric pump of simplified structure which is characterized by the inclusion of means whereby various quantities of oil or pumped fluid may be drawn from the pump by including output taps associated with the casing and arranged in spaced apart relation with respect to the radial movement of the rotor to tap off various wedges of oil at different pressures for service to various points in an engine in combination with the main supply through the rotor shaft.

Other objects of the invention will be appreciated by a study of the following specification taken in conjunction with the accompanying drawings, wherein:

Figur 1 is a view of an eccentric pump according to the present invention with one-half portion of the housing removed corresponding to view il of Figure 2.

Figure 2 is a sectional View of the pump of Figure 1 on the line 2-2 thereof but showing the complete housing.

Figure 3 is a cut-away perspective view of the rotor arrangement of the pump of the present invention.

Figure 4 is a sectional view of an improved type of valve according to the invention.

Figure 5 is a volume diagram of the quantity 2 of fluid delivered by each vane of the rotor in the pumping action.

Figure 6 is a sectional view of relevant portions of an engine of generally conventional construction illustrating the manner of use of a pump of the present invention in delivering oil under various pressures to various points in the engine.

Referring now more specifically to the drawings and particularly to Figures 1, 2 and 3, the pump of the invention is comprised of a rotor l having a shaft I l extending therefrom which may be driven by a suitable driving component (not shown) such as the crank shaft of an engine, the same forming a portion of the crank shaft if desired. The rotor includes an output shaft l2 carrying a threaded portion 13 and bored axially as indicated by numeral M. In the specific form of pump illustrated in Figures 1, 2 and 3, which is designed to serve as a general utility pump, the shaft 1 I is supported in bearing I carried by the casing it which forms essentially a half portion of the general housing H. The remaining half of the housing is in the form of a cover 18 bolted". to the casing by suitable bolts [9 and which car-- ries the shaft l2 and includes a communicating bore 20 carrying the fitting 2| from which the: pump delivers its main output of fluid.

The rotor assembly is designed to float axially in the housing I! and therefore, clearances are provided so that the sub rotor 22 is left undisturbed by such axial play in the rotor. The sub rotor includes a, vane carrier 23 which is cut away at spaced apart intervals to carry vanes 24 in the slots 25 thereof. Between each pair of vanes a communicating duct 25 is provided which at the inner ends are normally closable by a leaf valve 21. Each leaf valve 21 is mounted in a common annular chamber 28 formed in the interior of the sub rotor 22 which in turn communicates with a plurality of ports 29 in a communicating ring 30 which in turn in its inner face has a communicating channel 3| which communicates to a single bore 32 in the main rotor l0 terminating in the bore 14 thereof. In assembly, the main rotor component It! has placed thereon the communicating ring 30 and the sub rotor 22 is slid thereover and moved radially until the driving pin 33 thereof slips into the socket 34 in the driving ring 35 of the rotor. The assembly plate 36 is then assembled onto the threaded portion l3 of the shaft l2 and tightened down by employing the sockets 31 and a suitable wrench until either the width dimensions of the communicating ring 30 or the dimensions of the main rotor body limit the tightening action. At this point it will be realized that the tolerances with regard to the machining of the width dimension of the communicating ring 30 or the body of the rotor do not materially affect the operation of the rotor since it is only essential that the sub rotor 22 be of a width or thickness dimension materially less than the distance between the driving ring 35 and the assembly plate 36. In this connection it will be noted that the cavities 38 and 39 formed in the casing l6 and cover l8 respectively are of enlarged dimension as compared with the dimensions of the rotor to avoid any fine tolerance requirements since these are unnecessary. How-- ever, the one factor requiringattention as regards tolerance of machining is the thickness of the vane carrier 23 and the width of the vanes and the adjacent surfaces of the casing and cover, Thus the surfaces 40 and 4| of the casing and cover respectively should closely engage the surfaces of the vane carrier and the vanes carried thereby, but in this respect the tolerances adopted need not be finer than those required in normal careful machining practice, that is to say, plus or minus 53 of an inch is a suflicient degree of exactness for a pump to be used in pumpingfluids such as oil of the generally recognized medium grade for automobile services.

The vanes 2 are hot spring urged but move outwardly toward the-eccentric surface 42 under centrifugal force. Preferably the outer surfaces of the vane carrier 23 carry a trough 43 so that communication ofoil will be assured to the communicating duct 26 when an adjacent vane 24 is pressed furthest into its slot 25. In this connection it may be noted that it is not necessary for the outer surfacesofthe vane carrier to engage the eccentric surfaces" at any point. In fact, this is definitely to be avoided to obviate the necessity of tolerance with respect to the degree of eccentricity as between the rotor and the housing. By allowing a reasonable depth of vane carrier substantially as shown, the leakage path of oil down the sides of the-vane carrier and the vanes associated therewith isof suflicient length that fine tolerance requirements need not be resorted to. There is a certain degree of proportionality involved here which should be appreciated and it is not intended that the present disclosure should be construed as limiting the invention to the proportions shown here for purposes of description, since for fluids oflow viscosity and-light body an extended leakage path to provide increased resistance to leakage would be accordingly desired involving a greater height or depth to the vane carrier 23 in order to avoid costly machining which would ordinarily be demanded by very fine-tolerances in such instance.

Although I have found that a simple leaf spring member 2! preferably formed of springy brass is satisfactory and much more simple'and as effective as most ball type'valves for this purpose, I also have provided'a valve of this nature which by virtue of specific materials employed providesdistinct advantages over prior valves for this pur pose. The sectional form of such a leaf valve is illustrated in Figure! and comprises a central spring-like body 44 which maybe dipped in'o'r otherwise covered by a suitable adhering plastic material 45"or other deformable smooth coating which is substantially unaffected by the chemical nature of the fluid being pumped. In the pumping of fluids as medium oils for engine lubrication, I prefer to usea coating of a thermoplastic such as plasticized vinyl chloride, or vinyl chloride and vinyl acetate types generally known under the trade name Vinylite. In general, the rubber-like type of plastic material is preferred such as normally used for wire coating, tubing, and the like. By reason of the smooth surface provided, the leaf valve of this composite nature adheres very closely to the surfaces 46 of the annular chamber 28; Particles of foreign matter do not adhere to the coating material due to its smooth surface and rubber-like nature which assists in clearing during the pumping action.

Oil or fluid to be pumped is fed into the input chamber Hthrough a fitting 43 mounted in the casing t6, the input chamber being of slotted nature and extending arcuately and outwardly toward the fitting substantially as indicated by the dotted lines 48'a illustrating the terminal surface of the input chamber, which is of lesser width than the pumping vanes. The vanes 24 in sweeping in clockwise relation in Figure 1 over the surface 42 pick up oil or fluid lying in the eccentric space 46 between the subrotor vane carrier 23 and surfaces 480. and carry this fluid to a point 50 after which the eccentric relation decreases and the fluid begins to be compressed progressively.

As the pressure builds up before any one vane the leaf valve associated therewith opens at a predetermined pressure to allow the fluid to flow through the associated communicating duct to the chamber 28 of the sub rotor 22 thence through ports 29 of communicating ring 30, about the communicating channel 3| to the bore 32 and thence to the output fitting 2|. The mere pumping of the fluid in this manner, that is according to the principle just outlined, is known but according to the present invention means are provided in combination therewith whereby various outputs may be taken from the pump.

Referring to Figure 1, an output fitting 5| is provided which communicates by the bore 52 to the output chamber 53 in the form of the eccentric space illustrated which extends substantially from the point 50 to the point 54. The fitting 5| connects by means of suitable tubing 55 to an output point as indicated and at some point along the tubing a pressure control device 55 may be provided. 7

Referring also to Figure 5, the volume diagram shown illustrates by the bounds of the triangle ate the total volume of oil or pump fluid available from the discharge chamber 53 by reason of the pumping action of any one vane during its traverse from the point 50 in the clockwise direction to the point 54. In accordance with prior types of pumps of the present class wherein the pump fluid'was only drawn off through the central bore I4 of the pump the complete volume abc would be delivered through this central bore or port. The present invention, however, contemplates tapping off quantities from the volume diagram abc and in this connection it will be noted that the amount of fiuid drawn by the fitting 51 is represented by the shaded area 57. h

The pressure control device 55 of Figure 1 may be utilized where oil is being pumped for lubrication purposes. Thus, the device 56 includes a ball check valve 58 acting under spring pressure 59 which may be adjusted by the adjusting screw 60. This relief valve assembly determines the maximum pressure in the line 55', excess pressures causing a portion of the pump fluid to return through the line 61 to the sump or oil reservoir (not shown).

By employing relief valve arrangements in conjunction with the points to which pump fluid is supplied by the pump of the present invention, predetermined maximum pressures at various points can be provided. So long as the maximum pressure in the central bore I 4 is greater than the maximum pressures of any of the exterior outlets such as the outlet 5|, various combinations of pressures may be provided. In this connection also various output points of exterior nature such as an output fitting 5| are located clockwise in increasing pressure arrangement. That is to say, an output fitting located at the point 62 will deliver the residuum of the volume between the fitting 5! and the point 62 at a pressure greater than the pressure in the line 55 and at fitting 5|. It is obvious, however, that where fluid pressure is of no consideration, pressure control devices need not be employed, the volume diagram in Figure 5 being substantially independent of the pressures involved. Thus, a fitting at the point 62 will deliver a volume of fluid corresponding to the area 63 of the diagram. The central bore I I will deliver the remainder or the portion 64 of the diagram if two output fittings are employed. It will be appreciated that the number of output fittings is limited by the spacing of the vanes in that the radial distance between output fittings must be greater than the distance between any two vanes.

It will, therefore, be appreciated that the eccentric pump of the present invention, aside from being a simple device to manufacture, provides great flexibility in that it may be adapted to serve various points of an engine with supplies of oil for lubrication purposes or cooling purposes and at various pressures if desired. Thus, in Figure 6, a slightly modified type of pump 65 according to the invention has a large rotor shaft 66 wherein the bore 6! corresponds to the bore I4 of the previous description. In this case the bore 67 communicates to the oil duct '68 in a crank shaft assembly 69 whereby oil may be supplied through the ducts 10 to the bearings H of a connecting rod 12. An exterior type of output according to the invention may be taken from the outer region of the rotor 65 in a manner previously described with respect to the fitting 51 of Figure 1 by supplying a duct 13 which communicates by the passageways 14 and T5 to a reservoir U '55 which may serve to lubricate portions of a valve arrangement 1! in the head structure of an engine.

It is thus apparent that the pump of the pres ent invention may take various forms dependthe rotor with respect to the sub rotor without particular regard to tolerances except with respect to the vane carrier and the components surrounding it. Also the output fittings described with respect to Figure 1 may take various forms, it being only essential that in providing a plurality of outputs from the one pumping device it be appreciated that the quantity of of fluid drawn off is dependent upon the radial location of the output point.

It is therefore intended that the present disclosure should not be construed in any limiting sense other than that indicated by the scope of the following claim.

What I claim as my invention is:

An eccentric pump comprising in combination: a housing, a pump rotor having an axial bore, bearing means in said housing rotatably supporting said rotor therein and permitting axial movement of said rotor relative to said housing; a vane carrier supported for axial slidable movement over said rotor and rotatable therewith; pumping vanes projectable beyond the periphery of said vane carrier and supported for radial slidable movement therein; an annular recess in said housing having side Walls enclosing the sides of said vanes and vane carrier in close tolerance relationship and having an inner surface defining in conjunction with said carrier a crescent shaped cavity forming input and output pumping chambers; an annular chamber in said vane carrier adjacent said rotor; a radial passage in said carrier between each adjacent pair of pumping vanes extending from said annular chamber to the outer periphery of said carrier; a check valve in said annular chamber, extending over each of said radial passages; and a radial passage in said rotor communicating between said bore and said annular chamber.

LORNE F. KNIGHT.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,988,213 Ott Jan. 15, 1935 2,035,465 Erskine et al Mar. 31, 1936 2,065,008 Madle Dec. 22, 1936 2,266,191 Granberg Dec. 16, 1941 2,403,532 Hoover July 9, 1946 2,418,412 Kucher Apr. 1, 1947 2,462,214 Namur Feb. 22, 1949 2,462,732 Dusevoir Feb. 22, 1949 2,471,915 Thacher May 31, 1949 2,487,721 Minshall Nov. 8, 1949 2,491,670 Lipman Dec, 20, 1949 2,510,609 Tingle June 6, 1950 2,517,862 Frederick Aug. 8, 1950 2,558,970 Lipfert July 3, 1951

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