US20020102166A1

US20020102166A1 - Electric pump end cap with integrated electrical connection

Info

Publication number: US20020102166A1
Application number: US10/044,411
Authority: US
Inventors: Eric Keyster; James Blass; Terry Miller; Phil Hall; Paul Meyer
Original assignee: Caterpillar Inc
Current assignee: Caterpillar Inc
Priority date: 2001-01-31
Filing date: 2002-01-10
Publication date: 2002-08-01

Abstract

A pump end cap preferably includes a plastic molding that is shaped to include an external electrical socket and is internally shaped to include electric motor brush placement holders. Electric motor brushes are mounted on the holders. The electric motor portion of the electronic pump assembly is completed when the end cap is mated to an appropriate housing. By integrating a portion of the electric motor into the pump end cap, the need for wires extending from an electric motor terminal to the outside of the pump housing is eliminated. The present invention preferably finds application in fuel pump and filter assemblies used in conjunction with diesel type internal combustion engines.

Description

RELATION TO OTHER APPLICATION

This application claims priority to provisional application number 60/265,371, filed Jan. 31, 2001, and entitled Electric Pump End Cap With Integrated Electrical Connection.[0001]

TECHNICAL FIELD

The present invention relates generally to electric pump assemblies, and more particularly to a plastic molded end cap for a pump assembly that includes an integrated electric motor component.

BACKGROUND

Although electric fuel pump and filter assemblies have long been known in the art, engineers continue to seek ways to improve their designs. For instance, there is almost always room to improve reliability and decrease cost. One area in which reliability can generally be improved is by reducing part count and reducing the number of electrical connections and associated wiring necessary to bring electric power to an electric motor that is often positioned deep inside a housing at a relatively inaccessible location. In some instances, it is desirable that such assemblies not be serviceable in order to further reduce reliability concerns that can occur due to improper servicing of a nonserviceable component. Thus, there are often several conflicting problems when there is a desire to simultaneously reduce costs, improve reliability and include design features that render a nonserviceable component difficult to impossible to dismantle.

The present invention is directed to these and other problems associated with electric pump assemblies.

SUMMARY OF THE INVENTION

In one aspect, an electric pump end cap includes a plastic molding with an external face separated from an internal face by a circumferential side surface. The external face includes an electrical connector socket shape. The internal face includes at least one electric motor brush placement holder and defines a portion of a fluid passage.

In another aspect, an electric pump assembly includes an end cap attached to a housing to define an internal cavity. The end cap includes a plastic molding with an external face separated from an internal face by a circumferential side surface. The external face includes an electrical connector socket, and the internal face has mounted thereon first and second electric motor brushes. First and second conductors are at least partially positioned in the plastic molding and extend between the brushes and the electrical connector socket. A partial electric motor is positioned in the internal cavity in contact with the first and second electric motor brushes. A fluid pump is positioned in the internal cavity and operably coupled to the electric motor. At least one of the housing and the end cap define an inlet and an outlet.

In still another aspect, a method of assembling an electric pump includes a step of attaching electric motor brushes to a plastic end cap. Electrical conductors are extended from an external face of the end cap to the electric motor brushes. Next, a pump and a partial electric motor are positioned in a housing. The electric motor is completed by mating the end cap to the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1[0008] a-1 b are isometric and front views, respectively, of a fuel pump and filter assembly for an internal combustion engine according to one aspect of present invention;
FIG. 2[0009] a is a left side view of a pump assembly according to the present invention;
FIG. 2[0010] b is a sectioned side diagrammatic view of the pump assembly as viewed along section lines A-A of FIG. 2a;
FIG. 2[0011] c is a right side view of the pump assembly;
FIG. 2[0012] d is a partial sectioned side view of a pump housing/end cap deformation attachment according to one aspect of the present invention;
FIGS. 3[0013] a-3 b are isometric and bottom views, respectively, of an end cap assembly according to a preferred embodiment of the present invention;
FIGS. 4[0014] a-4 b are a pair of isometric views of a plastic molding according to another aspect of the present invention;
FIG. 5 is an isometric view of a conductor and brush assembly according to the present invention; and [0015]
FIGS. 6[0016] a-6 b are a pair of isometric views of a plastic molding according to another embodiment of the present invention.

DETAILED DESCRIPTION

Referring to FIGS. 1[0017] a and 1 b, a fuel pump and filter assembly 1 includes a housing 2 within which is positioned an electric pump 10 and a filter 3. This design is preferably not serviceable, meaning that it is preferable that the housing include features that prevent the electric pump assembly 10 from being removed, serviced and then replaced in housing 2. However, it might be desirable to allow a portion of the housing 2 open in order to replace filter 3 with a fresh filter during regular scheduled maintenance. The housing 2 defines an air vent 4, a fuel inlet 6 and a fuel outlet 7, all of which preferably include quick connect shapes in order to ease in the installation of the pump and filter assembly 1 between a fuel tank and an internal combustion engine. Housing 2 also defines a pump opening 5 within which electric pump 10 is installed, preferably irreversibly. Finally, pump 10 includes an electrical connector socket 42 to also ease in the installation in connecting the pump to an appropriate electrical power source. While the present invention has and is being illustrated in the context of a fuel pump and filter assembly, those skilled in the art will appreciate that the present invention could find potential application in processing other fluids besides fuel, and could find potential application outside of pumps used in conjunction with internal combustion engines.
Referring now in addition to FIGS. 2[0018] a-2 d, the structure of electric pump 10 will be described. Electric pump 10 includes a partial electric motor/pump assembly 12 a metallic can shaped housing 14 and an end cap 16. In order to make the pump and filter assembly 1 less serviceable, end cap 16 preferably includes a snap ring groove 40 that mates with a snap ring to a receiving groove defined by housing 2 in a conventional manner. Furthermore, the snap ring is preferably concealed from view at least in part by the inclusion of cover tabs 49 that tend to keep the snap ring concealed when pump assembly 10 is installed as shown in FIGS. 1a and 1 b. Also, tabs 49 also provide orientation, as the two are not the same size.
Can shaped [0019] housing 14 is preferably made from a suitable sheet metal material that can be deformed to provide a suitable and relatively irreversible attachment to end cap 16. When mated as shown in FIG. 2b, housing 14 and end cap 16 define an internal cavity 26 that includes a fluid passage 22 defined in part by plastic molding 15, which makes up the bulk of end cap 16. Housing 14 defines an inlet opening 20 and an outlet opening 18 that both open to internal cavity 26. Thus, when in operation, fuel is drawn into inlet opening 20 and exits pump assembly 10 via outlet 18 under the action of the electric motor and pump assembly 11/12. Those skilled in the art will appreciate that inlet 20 and outlet 18 could be relocated to any suitable location, including but not limited to the possibility of plastic molding 15 defining one or both of the inlet and outlet.
In this preferred embodiment, [0020] housing 14 includes a flared end 24 that facilitates the mating of housing 14 with end cap 16. The attachment is preferably completed by deforming a portion of housing 14 into at least one retention recess 36 defined by plastic molding 15. In the preferred embodiment illustrated, retention recess 36 includes an annular groove and the annular end portion 24 of housing 14 is deformed in a conventional manner, such as by use of a roller, into annular retention groove 36 as shown in FIG. 2d. This attachment strategy renders pump assembly 10 relatively unserviceable by making it difficult to impossible to disengage housing 14 from end cap 16 without damaging one or both components.
Referring in addition to FIGS. 3[0021] a and 3 b, end cap 16 includes a plastic molding 15 that includes an electrical socket 42 that is electrically connected to a pair of motor brushes 46 via a suitable conductor 43 (FIG. 5). When end cap 16 is mated to housing 14, a cylindrical portion 31 comes in contact with inner surface 13 of housing 14. Furthermore, end cap 16 includes at least one motor alignment guide surface 39 that mates into a recess in partial electric motor/pump assembly 12 in order to insure that brushes 46 are appropriately located on the armature of electric motor 11. In addition, motor alignment guide 39 helps to insure that a flow passage 35 defined by plastic molding 15 aligns with outlet 18 so that fluid passage 22 can communicate with outlet 18. In addition, plastic molding 15 includes a shaft support recess 38 that receives a portion of rotatable shaft 21 and also acts as a journal bearing for the same. Recess 38 could house a brass or other material journal bearing for increased run dry protection.
Referring to FIGS. 4[0022] a and 4 b, plastic molding 15 is shaped to include an external surface 30 separated from an internal surface 32 by a circumferential side surface 34. Side surface 34 is preferably shaped to include cylindrical portion 31 that closely matches the inside diameter of can shaped housing 14 (FIG. 2) and an annular retention groove 36 into which a flared end 24 of housing 14 is deformed in order to secure end cap 16 to housing 14. External face 30 is preferably molded to include a suitable electrical connector socket shape 42, which can be any type known in the art. Internal face 32 is preferably formed to include shaft support recess 38, a pair of brush placement holders 17 and a pair of inductor holders 33 (FIG. 3). Preferably, a conductor and motor brush assembly 43 of the type shown in FIG. 5 is attached to plastic molding 15 in a suitable manner, such as by the use of shunts, to produce an assembled end cap as shown in FIGS. 3a and 3 b. Conductors 43 are preferably positioned so that a pin portion 44 is exposed through external face 30 in socket 42, and brushes 46 are supported by brush holders 17. Preferably, conductors 43 include a conductor pin 41 that is attached to a wire 48, which is wound around an inductor core 45 and electrically connected to electric motor brush 46 by a brush support 47. Brush support 47 and inductor core 45 are received in and supported by brush placement holders 17 and inductor holders 33, respectively. Thus, end cap 16 carries at least one essential electric component necessary to complete an electric motor. In addition, the electrical connection made to socket 42 is done without having to connect wire between a separate motor terminal and a socket, and thus the integrated design eliminates the need for terminals on the electric motor.
Referring to FIGS. 6[0023] a and 6 b, a plastic molding 115 according to an alternative embodiment of the present invention is much like the plastic molding 15 described earlier except that it defines a flow passage 35 extending between its external face 130 and its internal face 132. This is an alternative to the side port openings 18 and 35 defined by housing 14 and end cap 16, respectively. The flow passage 135 preferably includes a quick connect shape 137 that is similar to that shown in relation to FIGS. 1a and 1 b. Like the earlier embodiment, plastic molding 115 is shaped to include brush placement holders 117 on the internal face and an electrical connector socket shape 142 on its external face. Inductor holders can also be part of this style connector. Like the earlier embodiment, external face 130 is separated from internal face 132 by a circumferential side surface 134 which includes at least one cylindrical portion 131 and preferably includes an annular retention groove 136. This embodiment also can include additional grooves for placement of O rings if it is desired to make the connection between the end cap and the housing fluid tight. Finally, like the earlier embodiment, internal face 132 includes a shaft support recess that receives and supports the rotatable shaft of the electric motor. It might also be desirable to insert a brass or other type of journal bearing for improved life running without fuel. If plastic molding 115 were substituted for plastic molding 15 described earlier and installed to create a complete pump assembly 10, flow passage 135 would open directly into, and define a portion of, flow fluid passage 22. In all other aspects, plastic molding 115 and plastic molding 15 are substantially similar.
Industrial Applicability [0024]
The [0025] pump assembly 10 preferably utilizes a partial electric motor/pump assembly 12 of a type manufactured by Airtex Products of Fairfield, Ill. This subassembly is then positioned within housing 14 as shown in FIG. 2b. Next, the plastic molding 15 or 115 is formed and electrical conductors are extended between the external face and electric motor brushes 46 that are attached to the end cap 16. Next, the electric motor 11 is completed by mating the end cap to the housing 14 as shown in FIG. 2b. In order to insure that complete mating as shown in FIG. 2b, it is preferably necessary to mate alignment guide surface 39 with an appropriate mating surface on the partial electric motor/pump assembly 12. This feature insures that electric brushes 46 will be properly located in the complete assembly and that flow passage 35 will align with outlet 18. In addition, the mating of the end cap 16 with housing 14 includes having shaft support recess 38 receive an end portion of rotatable shaft 21. This preferably is accomplished by making the centerline of shaft support recess 38 concentric with the centerline of cylindrical portion 34 that comes in contact with the inner surface 13 of housing 14. The end cap 16 is attached to housing 14 preferably by deforming an annular end portion 24 into an annular retention recess 36 formed on this side surface 34 of plastic molding 15. Those skilled in the art will appreciate that, in the event that plastic molding 115 is substituted for plastic molding 15, the assembly procedure is substantially identical.
The present invention has the potential advantage of integrating the electrical connections for the electric motor into the pump end cap in a way that reduces the need to extend wires or other conductors between electric motor terminals and the outside of the pump assembly. This is accomplished by mounting at least one electric motor component, such as brushes, on the pump end cap. In addition, by including appropriate geometry, one can be assured that the electric motor will be properly assembled when the appropriate mating surfaces come in contact with one another as illustrated in FIG. 2[0026] b. This structural strategy can allow for a reduction in part count and a substantial increase in reliability by eliminating electrical connections (between a terminal and an electric socket) that can eventually be problematic and/or lead to pump failure. By integrating some of the electric motor components into the end cap, cost can be reduced. Those skilled in the art will appreciate that other aspects, objects and advantages of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.

Claims

What is claimed is:

1. An electric pump end cap comprising:

a plastic molding with an external face separated from an internal face by a circumferential side surface, and said external face including an electrical connector socket shape, and said internal face including at least one electric motor brush placement holder and defining a portion of a fluid passage.

2. The electric pump end cap of claim 1 wherein said side surface of said plastic molding includes at least one housing retention recess.

3. The electric pump end cap of claim 2 including a first conductor partially positioned in said plastic molding and being exposed through said external face within said socket shape and through said internal face; and

a second conductor partially positioned in said plastic molding and being exposed through said external face within said socket shape and through said internal face.

4. The electric pump end cap of claim 3 including first and second electric motor brushes supported by said first and second brush placement holders, respectively.

5. The electric pump end cap of claim 4 wherein said fluid passage includes said plastic molding defining a flow passage extending between said internal face and one of said side surface and said external face.

6. The electric pump end cap of claim 5 wherein said side surface includes a cylindrical portion through which said flow passage opens; and

said at least one housing retention recess includes an annular groove positioned between said external face and said cylindrical portion.

7. The electric pump end cap of claim 6 wherein said internal face includes a motor shaft support recess.

8. The electric pump end cap of claim 7 wherein said internal face includes at least one motor alignment guide surface.

9. An electric pump assembly comprising:

a housing;

an end cap attached to said housing to define an internal cavity and including a plastic molding with an external face separated from an internal face by a circumferential side surface, and said external face including an electrical connector socket, and said internal face having mounted thereon first and second electric motor brushes, and first and second conductors at least partially positioned in said plastic molding and extending between said brushes and said electrical connector socket;

a partial electric motor positioned in said internal cavity in contact with said first and second electric motor brushes;

a fluid pump positioned in said internal cavity and being operably coupled to said electric motor; and

at least one of said housing and said end cap defining an inlet and an outlet.

10. The electric pump assembly of claim 9 wherein said end cap defines at least one housing retention recess; and

a portion of said housing being deformed into said housing retention recess.

11. The electric pump assembly of claim 10 wherein said at least one housing retention recess includes an annular groove; and

an annular end portion of said housing being deformed into said annular groove.

12. The electric pump assembly of claim 10 wherein said plastic molding defines a flow passage extending between said internal face and one of said side surface and said external face.

13. The electric pump assembly of claim 5 wherein said side surface includes a cylindrical portion in contact with an inner surface of said housing and through which said flow passage opens.

14. The electric pump assembly of claim 13 wherein said partial electric motor includes a rotating shaft received in a motor shaft support recess that is a portion of said internal face.

15. The electric pump assembly of claim 14 wherein said internal face includes at least one motor alignment guide surface mated to said partial electric motor.

16. The electric pump assembly of claim 15 wherein at least one of said housing and said end cap define an exposed snap ring groove.

17. A method of assembling an electric pump comprising the steps of:

attaching electric motor brushes to a plastic end cap;

extending electrical conductors from an external face of said end cap to said electric motor brushes;

positioning a pump and a partial electric motor in a housing; and

completing an electric motor by mating said end cap to said housing.

18. The method of claim 17 including a step of attaching said housing to said end cap at least in part by deforming a portion of said housing.

19. The method of claim 18 wherein said mating step includes a step of aligning a guide surface on said end cap with a mating surface on said partial electric motor.

20. The method of claim 18 wherein said mating step includes inserting a rotatable shaft of said partial electric motor into motor shaft support recess defined by said end cap.