US3775024A

US3775024A - Submersible fuel pump

Info

Publication number: US3775024A
Application number: US00225330A
Authority: US
Inventors: R Ulm; C Phillips; M Sullivan; L Collins; W Parrent
Original assignee: AIRTEX PROD DIVISION OF UNITED
Current assignee: AIRTEX PROD DIVISION OF UNITED; AIRTEX PROD DIVISION OF UNITED IND SYNDICATE US; UIS Inc
Priority date: 1970-05-20
Filing date: 1972-02-10
Publication date: 1973-11-27
Anticipated expiration: 1990-11-27

Abstract

A rotary electric fuel pump using a permanent magnet motor is constructed of parts having a simple geometric pattern for mass production by sheet metal stamping and plastic molding. The construction provides for housing a cylindrical magnet stator for a motor field and a high-speed armature. The fuel medium being pumped flows over the magnet effecting cooling, with some diverting of flow through the armature for cooling. A further feature resides in the construction of an impeller having flow passage to the stator slots phased in such a manner that peak flow pressure at the slots is evened out around the impeller. Thus, the impeller vane spacing is related to that of the stator slots that only one flow pressure peak occurs at a time, and such peaks occur sequentually at widely spaced points around the rotary axis. This minimizes electric current peaks and brush sparking as well as bearing wear. The construction is fully sealed for submerged use in fuel tanks.

Description

nited States Patent [191 lJlm et al.

[ Nov. 27, 1973 SUBMERSIBLE FUEL PUMP [75] inventors: Ralph E. Ulm; Claude F. Phillips;

" Michael J. Sullivan; Larry C.

Collins; William Russell Parrent, all of Fairfield, Ill.

[73] Assignee: V Airtex Products, Division of United Industrial Syndicate, New York, NY.

22 Filed: Feb. 10, 1972 211 App]. No.: 225,330

Related US. Application Data [62] Division of Ser. No. 37,951, May 20, 1970, Pat. No.

Primary Examiner-C. J Husar Attorney-Albert M. Zalkind [57] ABSTRACT A rotary electric fuel pump using a permanent magnet motor is constructed of parts having a simple geometric pattern for mass production by sheet metal stamping and plastic molding. The construction provides for housing a cylindrical magnet stator for a motor field and a high-speed armature. The fuel medium being pumped flows over the magnet effecting cooling, with some diverting of flow through the armature for cooling. A further feature resides in the construction of an impeller having flow passage to the stator slots phased in such a manner that peak flow pressure at the slots is evened out around the impeller. Thus, the impeller vane spacing is related to that of the stator slots that only one flow pressure peak occurs at a time, and such peaks occur sequentually at widely spaced points around the rotary axis. This minimizes electric current peaks and brush sparking as well as bearing wear. The construction is fully sealed for submerged use in fuel tanks.

3 Claims, 11 Drawing Figures SUBMERSIBLE FUEL PUMP This is a division, of application Ser. No. 37,951 filed May 20, 1970, now US Pat. No. 3,666,381.

Briefly, the invention in a preferred form comprises a steel housing or shell of generally cylindrical shape but formed with radial depressions. A cylindrical ceramic magnet of known type is used as a DC. motor field carried within the shell and an armature rotates within the magnet. Current to'the armature is brought in via a commutator and radially disposed brushes. The construction permits of inlet and outlet body members formed of molded plastic locked within the steel housing and providing bearing support for the armature, as well as support for the brushes. The cylindrical magnet is radially supported by the sleeve depressions, radially spaced within the sleeve, and longitudinally locked by the body members in conjunction with an intermediate pump stator. A complete flux trap, or substantially so, is provided for the magnet by the sleeve whereby all flux is confined within the sleeve and only minimum stray magnetic leakage may occur.

A centrifugal pump impeller of molded plastic is keyed to the armature shaft, being of conical shape having equally spaced radial vanes, the periphery of which is surrounded by a collar formed of the pump stator. The stator collar is slotted to take flow radially outward of the vanes and direct it longitudinally through the radial spacing between the outer sleeve and magnet.

The flow passes longitudinally over the outer surface of the cylindrical magnet to an annular outlet channel which connects to an outlet conduit integrally molded with the outlet body member.

The stator slots are numerically unequal to the impeller vanes and at such ratio numerically thereto that although equiangularly spaced, the output flow from the vanes through the slots occurs in a predetermined time order of flow peaks so that flow through each slot has a discharge peak to the output channel at a specific time in each rotation of the impeller. Accordingly, flow pulsation at maximum pressure occurring simultaneously from a plurality of slots is avoided and thus the pump operates with a minimum of shock and vibration.

The time pressure pulsations are spaced to apply the torque load through equally spaced increments, reducing the magnitude of the peak to peak electric current pulses of the electric motor driving the impeller and reducing sparking of the brushes. Also, due to the angular spacing of the impeller passage means in respect to the stator passage means, the relative orientation around the impeller shaft of radial reaction forces at peak pressures is widely distributed which minimizes bearing wear.

A detailed description of the invention now follows in conjunction with the appended drawing in which:

FIG. 1 is a section through a preferred form of the invention taken longitudinally;

FIG. 2 is a radial section through 2-2 of FIG. 1 showing the impeller and stator relationship;

FIG. 3 is a section through 3-3 of FIG. 1, omitting the armature;

FIG. 4 is a radial fragmentary section of modified construction of the impeller;

FIG. 5 is an exploded section of an impeller and stator in partial assembly;

FIG. 6 is a detail shown fragmentarily of the commutator brush construction in partial cross section, taken at right angles to FIG. 1;

FIG. 7 is an exterior view of one end of the pump;

FIG. 8 is a longitudinal exterior view;

FIG. 9 is an exterior view of the other end of the FIG. 10 is a longitudinal section of a modified pump and construction;

FIG. 11 is a fragmentary radial section through 1l11 of FIG. 10.

Referring to FIGS. 1 thru 9, the preferred form of the invention comprises a generally cylindrical steel sleeve or shell 10 closed at both ends by body member means such as the plastic body member 15 at the inlet end and plastic body member at the outlet end. The inlet end of the shell is radially deformed to fit tightly and sealingly against a conical shoulder 23 of a molded plastic body member 15 which abuts a pump stator 27, the stator in turn abutting a ceramic magnet of cylindrical shape. The oher end of the magnet is abutted by molded plastic body member 20 in turn sealingly locked within sleeve 10 by the inwardly directive radial flange 34. Accordingly, magnet 30 is longitudinally locked in the shell 10 by the body members and prevented from rotating by a tongue of body member 20 protruding into a notch 36 of the magnet.

Shell 10 is provided with arcuate depressions 38, a pair of such depressions being diametrically opposed as seen in FIG. 3, and the magnet 30 is radially disposed and located concetrically within shell 10 by being contiguous within the inner surfaces or walls of the depressions 38. Accordingly, the construction thus far described looks magnet 30 radially and longitudinally and affords large arcuate flow recesses intermediate the depressions 38 which recesses or passages extend longitudinally over magnet 30.

Inlet body member 15 has an entrance collar 47 around which is seated a filter tube 50 (fragmentarily shown) which tube which is understood to be made of any suitable filter material. When the pump is submerged in a fuel tank, fuel can pass thru the filter tube into collar 47 and inlet ports 55 to the hub of an impeller 60, there being three inlet ports such ports 55 as noted on FIG. 9.

A molded plastic impeller of conical form is provided having a plurality of vanes 64 equiangularly disposed and conically slanted as shown, being disposed in radial planes. As seen in FIG. 2, the specific embodiment being described has seven such vanes peripherally surrounded by a collar 68 of stator 27 which collar is essentially cylindrical but provided with twelve equiangular disposed slots 72 separated by fingers 74. The slots provide longitudinally flow passages for centrifugal flow induced by the impeller and directs such flow to the recesses 44. It will be understood that collar 68 is thus longitudinally open at the beginning and end of each slot 72 and that the fingers 74 of the collar abut at their upstream ends with body member 15.

The stator 27 has a dowstream collar 76 extending into engagement with magnet 30. Accordingly, as heretofore mentioned, the stator is an abutment member between body member 15 and magnet 30 at the upstream end of the magnet. At the downstream end of the magnet, body member 20 is formed with a continuous wall 76 effecting a radial edge 79 abutting the magnet. Body member 20 is also suitably formed with a radial flange 80 which seats against shell flange 34 and the molding which forms body member 20 is provided with an internal annular outlet channel 82 circumferentially surrounding wall 78 and from which channel extends an outlet conduit 84 all integrally molded therewith. Any suitable tubing can be connected to conduit 84 for fuel discharge from the pump leading out of the fuel tank to an engine carburetor, in a well understood manner.

Referring to the foregoing it will be understood that ingress of fuel via filter 50 can be centrifugally pumped by rotation of impeller 60 whence fuel discharge is directed through slots 72 of stator 27 longitudinally to recesses 44, over most of the exterior areas of magnet 30 and thence to outlet channel 82 and conduit 84.

It will be appreciated that the radial spacing between the magnet and shell although not completely about the periphery of the magnet is sufficient to permit flow without undue restriction.

Rotation of the impeller is effected by an armature 88 of a DC permanent magnet motor, the magnet 30 being the flux field therefore. The armature has a commutator 92 and a shaft 96 extending thru the construction, in a conventional manner, and to which the impeller is keyed, wherein one end of the shaft has suitable bearing in body member and the other end has similar bearing in body member 20. The bearing surfaces are, of course, coaxial with the shaft and are provided by the

hubs

100 and 103 molded into the respective body members as shown. In the case of the downstream end of the shaft 96, the hub 100 is elongated for purposes of accomodating a ball and spring whereby the ball is pressed against the respective shaft end to bias the armature into a predetermined position wherein the other end of the shaft has its end abuting the closed end of hub 103.

As seen in FIG. 6 a radial brush arrangement is preferred and suitable bosses 108 are integrally molded with the body member to accomodate commutator brushes 112 spring biased and retained by capa 115 which secure connection terminals 118 all in a conventional manner wherein the caps may be welded to the body member 20, as shown.

In order to provide for internal cooling of the motor a small passageway 120 is slotted through collar 76 whence flow from the stator can to any desired extent be diverted into the armature region to flow through the armature within the housing therefore provided by the body members and the magnet, such flow having egress via a slot 125 at edge 79 in body member 20 into outlet conduit 84. Thus any desired amount of cooling flow would be provided which flow is continuous for cooling the armature, whereas general cooling of the motor is afforded by the longitudinal flow over the magnet. The magnet is thus kept cool while absorbing heat from fuel passing through the armature chamber thereby augmenting the cooling effect on the armature.

An important feature of the invention resides in the fact that the numerical ratio of impeller vanes to stator slots is such as to permit phasing of vane progression passing the slots in a timed order so that flow peaks occur in a predetermined sequence and never simultaneously from any two slots. Thus, as seen in FIG. 2 the progression of flow peaks will be in accordance with numerals 1-7 noted on the vanes, the direction of rotation of the impeller being counterclockwise as indicated by the arrow. By providing 7 vanes and 12 slots there are 12 flow peaks per rotation of the impeller for each vane occurring in the numerical order l-2-3-4-5-6-7, shown on FIG. 2. It will be noted that flow peaks occurring through the slots are separated as to respective slots by a wide angle, about as seen on FIG. 2. This geometrically distributes the flow peaks about the periphery of the stator to minimize reactive forces. In other words, peak flow caused by vane l is followed by peak flow caused by vane 2 and then peak flow caused by vane 3, etc., all such peak flows being timed so as to occur at widely separated points around the stator, wherein the timing is effected by a suitably selected ratio of the number of impeller vanes to the number of stator slots 72. In this instance seven vanes and twelve slots are shown but it will be apparent that other ratios are usable for peak flow distribution effect at wide angles.

Referring to FIG. 4, a modification of the impeller is shown wherein grooves 2 and 4' are molded between raised wedges such as W. The grooves perform the function of the vanes of FIG. 2 and merely represent an alternate form of an injection molded impeller. The stator would be the same as heretofore described.

Referring now to FIG. 5, a detail of assembly is shown in an exploded view to illustrate the keying ribs, knurls, or flutes F milled or pressed into armature shaft 96 with impeller 60 being shown partially forced thereon so as to be keyed thereto, whereby a complete sub-assembly comprises the armature, the stator and impeller.

Referring to FIGS. 10 and 11 a modification using essentially all molded plastic components is illustrated wherein the body member means comprises an integral molding 200 having the cylindrical shell portion 205, the outlet annular channel 210 and outlet conduit 215. The molding has cavity 220 forming a part of the housing for the armature 225 and terminating in a lip or edge 230 which abuts the cylindrical field magnet 235. A second molded body member 240 is formed so as to effect the stator for the pump by providing the longitudinal slots 245 with spaced fingers 247, surrounding the periphery of impeller 250. The slots communicate with arcuate grooves 255 molded into the wall of shell portion 205 (FIG. 11) and which grooves are recesses corresponding to the longitudinal flow passages 44 of FIG. 3, However, any number of such grooves 255 may be provided. The lands 260 between grooves support the magnet 235 with an intermediate steel ring 265 fitting tightly over the magnet and force fitted against the inner surfaces of the lands. Accordingly, the magnet is radially located by the lands but secured longitudinally by press fitting with longitudinal location being determined by the peripheral edge 230. The impeller may have seven vanes and the stator twelve slots as in FIG. 2.

The body member 240, which integrally combines the stator is longitudinally locked by virtue of the ends of the stator fingers 247 abutting the ends of various lands 260 and by the deformation radially of the end of housing portion 205, as by heat and pressure, into sealing engagement at 270 with the conically shaped flange of body member 240.

The body member is provided with the inlet ports 275 and accordingly it will be apparent that flow takes place through the pump in essentially the same manner as heretofore described for FIG. 1, i.e., from ports 275 to the impeller and thence to stator slots 245, grooves 255, annular channel 210 and outlet conduit 215.

The armature is mounted in a manner similar to that heretofore described, having shaft ends with bearing rotation in respective body members and spring pressed ball bias in body member 200. However, the other body member may likewise be provided with a ball 260 as an anti-friction bearing. Metallic bushings such as 285 may be used for bearing support within the body members, if desired.

We claim:

1. A centrifugal pump comprising a rotary impeller having a plurality of vanes and a stator comprising a plurality of longitudinally directed flow passages arranged peripherally about said impeller, wherein the number of vanes is unequal to the number of stator flow passages; an electric motor of the brush and commutator type for driving said impeller; said vanes being equally angularly spaced and said flow passages being equally angularly spaced, and wherein the number of vanes is related to the number of flow passages so as to effect a maximum pressure peak occurring in said passages in a predetermined sequence in order to avoid occurrence of simultaneous maximum pressure peaks in any two passages and wherein maximum pressure peaks occur in said sequence through non-adjacent passages.

2. A centrifugal pump as set forth in claim 1, wherein the numerical ratio of vanes and flow passages effects separation of sequential maximum pressure peaks through passages separated angularly approximately 3. A centrifugal pump as set forth in claim ll, wherein there are seven vanes on said impeller and twelve passages in said stator.

Claims

2. A centrifugal pump as set forth in claim 1, wherein the numerical ratio of vanes and flow passages effects separation of sequential maximum pressure peaks through passages separated angularly approximately 150*.

3. A centrifugal pump as set forth in claim 1, wherein there are seven vanes on said impeller and twelve passages in said stator.