Patent Application
20110002798
The present disclosure relates generally to a fluid tank and a pump for pumping fluid out of the tank.
Fuel tanks for vehicles typically include a fuel pump disposed entirely within the fuel tank. The fuel pumps are mounted in the fuel tank through a hole in the tank which must subsequently be closed and sealed. The fuel pumps typically include a motor and a pumping element driven by the motor with both the motor and pumping element carried as a single unit within a casing. To access the fuel pump, the seal must be broken and the entire fuel pump removed from the tank through the hole. This is true even if only part of the fuel pump, for example the motor, needs to be serviced or replaced.
A fluid tank assembly may include a fluid tank having a wall defining an internal volume in which a fluid is received and a fluid pump. The fluid pump may have a motor including an electrically driven motor, a pumping element driven to rotate by the motor, a dividing wall disposed between and separating the motor and the pumping element, and a magnetic coupling between the motor and the pumping element and operative through the dividing wall to couple the motor with the pumping element. The motor may be located outside of the internal volume of the fluid tank and the pumping element may be located inside of the internal volume of the fluid tank.
A fluid pump may include a motor, a pumping element, a dividing wall and a magnetic coupling. The pumping element may be driven to rotate by the motor. The dividing wall may be disposed between and separating the motor and the pumping element. And the magnetic coupling may be provided between the motor and the pumping element and operative through the dividing wall to couple the motor with the pumping element, wherein the motor is carried separately from the pumping element so that the motor and pumping element can be installed and removed separately from each other.
The following detailed description of preferred embodiments and best mode will be set forth with reference to the accompanying drawings, in which:
Referring in more detail to the drawings,
The fuel tank may include one or more walls 14 defining an internal volume 16 in which the fluid is contained. The fuel tank wall(s) 14 may be formed of any suitable metal or non-metallic material. In one form, the fuel tank 10 may be formed from several layers of polymeric materials, in a so-called “multi-layer” fuel tank. As shown in
In one implementation, the fuel tank 10 may include a recess 24 or other area in or on which the pump 12 may be mounted. In the implementation shown in
In at least one implementation, the pump 12 may include a housing 40 that may be coupled directly to a tank wall 14, a pump assembly 42 carried in the housing 40 to extract, pressurize, and discharge liquid from the pump 12, and a motor assembly 44 coupled to the pump assembly 42 to drive the pump assembly 42. The motor assembly 44 and pump assembly may be separated by a dividing wall 46. In one form, the dividing wall 46 is a portion of the fuel tank wall 14, and as more specifically shown in
The motor assembly 44 may include a motor 50 and an output shaft 52 that rotates with or is rotated by the motor 50. The motor 50 may be of any suitable construction including, for example without limitation, brush-type and brushless DC motors. For example, the motor 50 may provide about 30 m-Nm of torque at 13 Volts and 1.6 Amps at about 4,500 RPM, and may be an HC series motor available from Johnson Electric Industrial Manufactory Ltd., of Hong Kong. Another exemplary motor is provided by Minebea Co., Ltd., of Japan, under the model number BLDC36. The motor 50 may have a casing 54 surrounding its internal components and the motor casing 54 may be closely received in the first skirt 30. The first skirt 30 may both hold the motor 50 and damp vibrations and noise from the motor. The output shaft 52 may have a drive feature or otherwise be coupled to a drive member 56. Exemplary drive features or couplings may include a set screw (not shown), a spline connection, mating non-circular drive features, or the like. A bearing and/or support 58 may be provided on or adjacent to the bottom wall 26 to support an end of the output shaft 52 and prevent wear of the bottom wall 26.
The drive member 56 may include a housing 60 coupled to the output shaft 52 and one or more magnetic field producing members such as the magnets 62 carried by the housing 60, circumferentially disposed around the shaft 52. The housing 60 may be formed of any suitable material, including various plastics. Because the housing 60 is not exposed to the liquid being pumped, the housing 60 need not be formed of a material that is impervious to or otherwise compatible for use in contact with the liquid. The housing 60 may be retained or supported on the output shaft 52 by, for example, a press fit or a washer and clip, such as a spring clip 64 coupled to the output shaft 52. As shown, the housing 60 includes one or more pockets 66 in which the magnets 62 are received. The pockets 66 could completely enclose the magnets 62 such as by overmolding the housing 60 on the magnets 62, or the pockets 66 could be open at one face so that, when the magnets are disposed within the pockets 66, one face of the magnets is exposed along one face of the housing. In that arrangement, the face of the housing 60 may be disposed adjacent to the bottom wall 26 of recess 24. In general, the magnets 62 provide a magnetic field onto and through the bottom wall 26. Of course, the magnet(s) 62 could be provided in any desired shape, configuration or arrangement including, but not limited to, a ring-shaped magnet, a flat disc magnet, or a plurality of magnetic segments or pieces spaced apart around the shaft 52. The drive member 56 may be constructed and composed of one or more rare-earth magnets carried by a stainless steel housing, or overmolded with phenolic or polyphenylene sulfide (PPS) resin. The magnets 62 may be composed, for example, of neodymium, iron, and boron (Nd2Fe14B). In another example, the drive member 56 may be commercially available from Magnetic Technologies, Ltd. of Oxford, Mass. An exemplary coupling is an MTD-0.2 ASSY having 0.2 Nm of slip torque and constructed with an aluminum housing 60 and six magnets 62. The housing 60 and magnets 62 rotate with the output shaft 52 when electrical power is provided to the motor 50.
The pumping assembly 42 may include the pump housing 40, a driven member 70 disposed within the housing 40 and a pumping element 72 coupled to and driven by the driven member 70. The driven member 70 may include a housing 74 and a member responsive to the magnetic field of the drive member 56, such as one or more magnets 76 or other member(s) that may be driven by the magnetic field provided from the magnets 62 of the drive member 56. The housing 74 may be constructed substantially similarly to the drive member housing 60 and the magnets 76 may likewise be of the same construction and material(s). The driven member housing 74 may include one or more fingers 78 adapted to be coupled to the pumping element 72 to couple the driven member 70 and pumping element 72 for co-rotation. The housing 74 may also include a central passage 80 in which a shaft 82 is received. Further, because the housing 74 may be exposed to the liquid being pumped, it may be formed of a different material than the drive member housing 60, if desired, and in particular, of a material suitable for use in the liquid being pumped. The magnets 76 may also be sealed within the housing 74 and isolated from the liquid, if desired or required in a particular application. The shaft 82 may be stationary and may support and maintain the position of the housing 74 and other components in the pumping assembly 42. A bearing 84 may be disposed between the housing 74 and the shaft 82 to facilitate rotation of the housing 74 relative to the shaft 82. The pump housing 40 may be crimped, rolled or otherwise formed around or adapted to receive the housing 74.
The pumping element 72 may be of the gerotor-type including inner and outer rotors or gears as is known in the art, a turbine type with an impeller, or any other suitable pumping element. In the implementation shown in
The pumping channels 88 may be defined in first and second plates 94, 96 which may be disposed on opposed sides of the impeller 72. The first plate 94 may include a central passage 98 through which a portion of the driven member 70 and the shaft 82 extend. The second plate 96 may include a blind bore 100 adapted to receive and support an end of the shaft 82. A guide ring 102 may be disposed around the impeller 72 and between the plates 94, 96. The guide ring 102 may ensure proper spacing between the plates 94, 96 to permit the impeller 72 to rotate relatively freely between the plates. Instead of the guide ring 102, one or both plates 94, 96 may include, in one piece, a flange adapted to engage the other plate and define a suitable gap between the plates in which the impeller 72 is received. That is, a guide ring or spacer could be formed in one-piece with one or both plates 94, 96 rather than being provided as a separate component. An inlet 104 through which liquid enters the pumping assembly 42 and an outlet 106 through which liquid is discharged under pressure from the pumping assembly 42 may be formed in one or both of the plates 94, 96. The inlet 104 may be a port formed in one plate, and the inlet port may be coupled to a filter 108 via an adapter 110, extension or conduit. The outlet 106 may communicate with an outlet nipple 112 to which a hose or other conduit may be coupled to route the pressurized liquid as desired. In the implementation shown in
The pump housing 40 may be formed to, received, crimped or rolled around the first and second plates 94, 96 to hold the pumping assembly 42 together and prevent or reduce leaking of the liquid from the pump 12. The pump housing 40 may be relatively loosely received around the driven member 70 to prevent interference with the rotation of the driven member 70. In this regard, a clip may be connected to the shaft 82 (perhaps with a thrust washer) to limit or otherwise restrain axial movement of the driven member 70 that might cause engagement or interference with the pump housing 40. A portion of the pump housing 40 may be received and retained in the second skirt 36, such as by a press-fit and/or a clip, fastener or other retention feature.
In operation, the motor 50 is energized with electrical power so as to rotate the output shaft 52 and the drive member 56 coupled to the shaft 52. Because of the magnetic attraction therebetween, rotation of the drive member 56 causes the driven member 70 to rotate about the stationary shaft 82 and within the pump housing 40. Because of the mechanical connection therebetween, rotation of the driven member 70 causes rotation of the impeller 72. Accordingly, operation of the motor 50 causes operation of the pumping assembly 42 through the wall 46 disposed therebetween.
With the pump 12 operating through the wall 46 disposed between the motor assembly 44 and the pump assembly 42, the motor assembly 44 can be isolated from the liquid being pumped. The motor assembly 44 can also be removed from the tank 10 for service or replacement without having to access the internal volume 16 of the tank 10 which prevents having to break any seals and having to reseal any openings or flanges of the tank 10. Further, the pump assembly 42 can be provided within the tank 10 without a separate opening required in the tank 10. For example, the pumping assembly 42 could be installed into the tank 10 through an opening provided for another component (e.g. a vent valve or a fill pipe through which fluid is added to the tank). As another example, in a tank 10 formed from two halves that are welded are otherwise sealed together, the pumping assembly 42 may be mounted in one half of the tank prior to connecting the two halves together. As yet another example, the pumping assembly 42 could be mounted on a support structure about which a tank 10 is blow molded (or otherwise molded) with the support structure locating and retaining the position of the pumping assembly. Not providing a separate opening through the fuel tank 10 for the pump 12 can reduce vapor permeation through the tank 10 and the likelihood of liquid leaking from the tank. It can also prevent a reduction in the structural integrity of the tank 10 by reducing the number of openings formed in the tank 10.
The tank wall 14, or the dividing wall 46 across or through which the pump 12 operates, may be composed of a nonmagnetic material or a material that is not significantly magnetically susceptible, yet permits the magnetic field to permeate therethrough. For example, the wall across or through which the pump 12 operates may be composed of any suitable polymeric material, for example, polyamide or NYLON 6/6, or a metal such as a stainless steel that is sufficiently non-magnetic or is sufficiently magnetically permeable, for example austenitic or nickel containing stainless steel. In at least some implementations, the dividing wall (which may be a portion of the tank wall as previously set forth) may be up to about 5 mm in total thickness, and in some implementations, the dividing wall may be between about 2 mm to 4 mm in total thickness.
Another implementation of a tank 200 and pump 202 is shown in
To locate and hold the pump components relative to the tank 200, and to close and seal the opening 204, a flange housing 210 may be provided. The flange housing 210 may include a radially outwardly extending mounting flange 212 that overlies a portion of the tank wall 206 surrounding the opening 204 and is sealed thereto. The seal may be temporary, such as by one or more clips of clamping devices, or the seal may be permanent, such as may be formed by welding the flange to the tank wall 206. The flange housing 210 may also include a skirt 214 defining a first receptacle in which the motor 50 and drive member 56 are received, and a second skirt 216 defining a second receptacle in which the driven member 70, impeller 72 and related components are received. This may facilitate manufacture of the tank 200 as no first skirt 30 or second skirt 36 needs to be formed on the tank 200 in this implementation. The flange housing 210 may further include a dividing wall 46 extending between and separating the drive member 56 and the driven member 70. Accordingly, in this implementation of the pump 202, the dividing wall 46 is defined by the flange housing 210 and not the tank wall 206. The dividing wall 46 may be provided in the area of the opening 204, or inside or outside of the internal volume 16 of the tank 202 which may greatly increase the ability to locate the pump 202 in a desired location or orientation relative to the tank 200. The flange housing 210 can be formed of any suitable material(s) for use with the magnetic coupling between the drive and driven members 56, 70, and for use in the particular liquid contained in the tank, including, for example, the same material(s) from which the tank 200 is made. The flange housing 210 may be formed as a single piece to reduce or eliminate vapor or fluid leak paths, and for improved structural integrity. Also, because the dividing wall 46 is not part of the tank 200, and the drive and driven members 56, 70 are spaced from the tank 200, the tank 200 need not be formed of a material suitable for use with the magnetic coupling.
As shown in
Accordingly, the pump 12, 202 may be provided in a wide range of locations and orientations relative to the tank 10, 200. The motor 50 and drive member 56 can be removed from the tank 10, 200 without having to access the internal volume 16 of the tank 10, 200 or break any seals of the tank. And the motor 50 and drive member 56 can be serviced or replaced, without having to move, replace or disturb the pumping assembly 42. This greatly improves the in-service life of the pump 12, 202 and tank 10, 200, and can greatly reduce the repair and maintenance costs of the pump and tank.
While the forms of the invention herein disclosed constitute presently preferred embodiments, many others are possible. It is not intended herein to mention all the possible equivalent forms or ramifications of the invention. It is understood that the terms used herein are merely descriptive, rather than limiting, and that various changes may be made without departing from the spirit or scope of the invention.
This is a nonprovisional application that claims the benefit of, and incorporates by reference in its entirety, U.S. Provisional Application Ser. No. 61/222,517, filed on Jul. 2, 2009.
| Number | Date | Country | |
|---|---|---|---|
| 61222517 | Jul 2009 | US |
