EP3114350B1 - Three-gear pump system for low viscosity fluids - Google Patents
Three-gear pump system for low viscosity fluids Download PDFInfo
- Publication number
- EP3114350B1 EP3114350B1 EP15707497.2A EP15707497A EP3114350B1 EP 3114350 B1 EP3114350 B1 EP 3114350B1 EP 15707497 A EP15707497 A EP 15707497A EP 3114350 B1 EP3114350 B1 EP 3114350B1
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- EP
- European Patent Office
- Prior art keywords
- gear
- driven gears
- pump system
- drive
- drive gear
- Prior art date
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- 230000008878 coupling Effects 0.000 claims description 9
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- 238000005859 coupling reaction Methods 0.000 claims description 9
- 239000000463 material Substances 0.000 description 6
- 230000008901 benefit Effects 0.000 description 5
- 238000006073 displacement reaction Methods 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 239000000446 fuel Substances 0.000 description 3
- 230000003993 interaction Effects 0.000 description 3
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C2/14—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2/00—Rotary-piston machines or pumps
- F04C2/08—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C2/12—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C2/14—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
- F04C2/20—Rotary-piston machines or pumps of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with dissimilar tooth forms
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2240/00—Components
- F04C2240/50—Bearings
Definitions
- the present application relates generally to fluid pump systems, and more particularly to fluid pump systems and multi-gear configurations for fluid pump systems configured for use with low viscosity fluids.
- Pump systems for low viscosity fluids are used in numerous applications.
- low viscosity oils are commonly used in various diesel engine systems for construction and transportation vehicles.
- Methanol or ethanol based fuel systems including for example jet fuel systems and high performance vehicle systems, also incorporate pumps in their fuel systems.
- Pump efficiency is particularly significant for low viscosity fluids such as those utilized in the referenced exemplary applications.
- Low viscosity fluids tend to flow more readily, and thus can leak or otherwise flow into undesirable areas of the system if not pumped efficiently.
- the advantage of the three-gear pump in improving volumetric efficiency by reducing leakage is described in US2008/0056926 A1 . This problem is exacerbated when high outlet pressure is required of the pump.
- Low-viscosity fluid pump systems commonly are used in vehicle and transportation systems. Pumps in such applications therefore must be compact. It is difficult to design a pump that is sufficiently compact, and yet still handle the loads associated with the high pressures and flows particularly required for low-viscosity fluid applications.
- Multi-gear pumps may be utilized in such systems, which have an advantage of reduced gear facewidth per unit of displacement, so as to permit a lower shaft load per gear at a given pump displacement and running speed.
- Many conventional configurations use a two-gear pump, including a drive gear and a driven gear.
- Three-gear pumps have been employed, in which a center or drive gear drives two opposite driven gears to pump the fluid.
- Such three-gear pumps have an advantage in that the drive gear load tends to be balanced by two high-pressure and two low-pressure ports located diagonally opposite to each other adjacent the driven gears. This configuration enhances the load carrying capability of the pump, but supporting loads on the two driven gears is still of concern.
- EP 2055954 A1 discloses a double gear pump having a drive gear, two driven gears, a first bearing that supports a drive shaft of the drive gear and a second and a third bearings that support rotating shafts of the two driven gears, wherein the bearing length of the first bearing is shorter than the bearing lengths of the second and third bearings.
- the present invention is a three-gear pump system in which the driven gears have an enhanced bearing structure, and the center or drive gear need not have a robust bearing support structure.
- the bearing structures supporting the driven gears can be enlarged relative to conventional configurations, which permits higher bearing loads to be carried.
- the three-gear pump system includes a housing and a three-gear configuration within the housing that pumps fluid from one or two fluid inlets to one or two fluid outlets.
- the three-gear configuration includes a center drive gear, a first driven gear and a second driven gear positioned on opposite sides of the drive gear.
- the drive gear meshes with the driven gears to drive the driven gears, and the driven gears are radially supported within the housing by a bearing structure for rotation of the driven gears about respective axes.
- the balanced radial loads on the drive gear eliminate the need for bearing support of the drive gear, which is free to float relative to the driven gears.
- the drive gear may have a larger diameter and a greater number of gear teeth as compared to the driven gears.
- the pump system may include a pump head that houses the three-gear configuration, a motor, and a magnetic coupling that transmits torque from the motor to a drive shaft that drives the drive gear.
- the three-gear pump system particularly is suitable for pumping a low viscosity fluids at high pressures and running speeds.
- Fig. 1 is a drawing that depicts an exemplary conventional two-gear arrangement 10 of gears for a two-gear pump system.
- Fig. 1 depicts the limitations of a two-gear configuration with respect to bearing size and the resultant bearing load capability.
- a first gear 12 may be a drive gear that drives a second or driven gear 14.
- the gears may be spur gears by which the drive gear drives the driven gear via interacting or meshing gear teeth as is known in the art.
- a center distance is deemed to be the distance between the rotating axes of the gears.
- Fig. 1 is a drawing that depicts an exemplary conventional two-gear arrangement 10 of gears for a two-gear pump system.
- Fig. 1 depicts the limitations of a two-gear configuration with respect to bearing size and the resultant bearing load capability.
- a first gear 12 may be a drive gear that drives a second or driven gear 14.
- the gears may be spur gears by which the drive gear drives the driven gear via
- a wall thickness is a distance between the bearing pockets of the two gears.
- a maximum thickness of a bearing to support the gear shafts or journals is the difference between the center distance and the wall thickness. If ball bearings are employed as the bearing structure, the maximum distance would correspond to a maximum outer diameter of the ball bearings. The resultant maximum distance or outer ball bearing diameter is less than the pitch diameter of the gears in the two-gear arrangement of Fig. 1 .
- Fig. 2 is a drawing that depicts an exemplary three-gear arrangement 20 of gears for a three-gear pump system in accordance with embodiments of the present invention.
- Fig. 2 demonstrates that an enlarged bearing size can be utilized with a three-gear arrangement as compared to a two-gear arrangement. With the enlarged bearing size, bearings are capable of carrying higher loads.
- the three-gear arrangement 20 includes a center drive gear 22 that drives a first driven gear 24 and a second driven gear 26.
- the two driven gears are positioned on opposite sides of the drive gear such that the axes of rotation of the three gears are aligned.
- the gears in the three-gear configuration may be spur gears by which the drive gear drives the driven gears via interacting or meshing gear teeth as is known in the art.
- Equation (1) is that the maximum bearing thickness, or in the case of ball bearings the maximum ball bearing outer diameter, is slightly larger than the outer diameter of the driven gears, which also is significantly larger than the maximum bearing thickness calculated for the two-gear configuration of Fig. 1 .
- a three-gear pump system configuration in which the driven gears are each supported by a bearing structure having a thickness up to the maximum as determined by Equation (1).
- the load on the center or drive gear is balanced to near zero by the positioning of the two driven gears.
- the drive gear acts as an overhung load driven by a drive shaft mechanism, such as for example a keyway or spline. Accordingly, the drive gear can rotate freely between the driven gears without any separate bearing structure for the drive gear.
- the drive gear is free to float radially relative to the driven gears without a separate or independent bearing structure, it is said to be a "floating drive gear" between the driven gears.
- the thicknesses of the bearing structures for the driven gears can be increased to the maximum permitted by Equation (1), without any potential interference by a separate bearing structure for the drive gear.
- the bearing structures for the driven gears are further enhanced as compared to conventional configurations in which the drive gear typically is provided with its own support bearing.
- a three-gear pump system includes a housing and a three-gear configuration within the housing that pumps fluid from a fluid inlet to a fluid outlet.
- the three-gear configuration includes a center drive gear, and a first driven gear and a second driven gear positioned on opposite sides of the drive gear.
- the drive gear meshes with the driven gears to drive the driven gears, and the driven gears are radially supported within the housing by a bearing structure for rotation of the driven gears about respective axes.
- the drive gear is free to float radially relative to the driven gears.
- Fig. 3 is a drawing that depicts a first exemplary three-gear configuration 30 for a three-gear pump system in accordance with embodiments of the present invention.
- Fig. 3 is taken at a side view of the three-gear configuration.
- the three-gear configuration 30 includes a center drive gear 32 that drives a first driven gear 34 and a second driven gear 36.
- the two driven gears are positioned on opposite sides of the drive gear such that the axes of rotation of the three gears are parallel and aligned.
- the drive gear 32 is driven by a drive shaft 38 that ultimately is driven by a motor (not shown).
- the drive gear 32 in turn drives the driven gears 34 and 36, which rotate respectively in conjunction with gear shafts 40 and 42.
- the rotation of the gears causes displacement of the fluid so as to pump fluid from an inlet side 44 to an outlet side 46.
- the three-gear configuration 30 further has a bearing structure that includes bearings 48 and 50 positioned respectively adjacent to the driven gears 34 and 36.
- the bearing structures 48 and 50 are configured as a plurality of sleeve bearings that radially support the journals or gear shafts of the driven gears for rotation of the driven gears about respective axes.
- the plurality of sleeve bearings may be configured as sleeve bearing pairs, in which one sleeve bearing is positioned on portions of the gear shafts 40 and 42 on opposite sides of the driven gears.
- the sleeve bearings may be pressed into a surrounding pump housing of the pump system. In such embodiment, therefore, the sleeve bearings remain fixed and thus do not rotate, with the shafts of the driven gears rotating relative to the sleeve bearings.
- the gears may be formed of a rigid metallic material, such as stainless steel or other suitable metals.
- the sleeve bearings may be formed of a rigid polymer or any suitable bearing grade plastic material as are known in the art. As such, the bearings tend to be softer than the gears, and bearing wear is a concern. Bearing wear changes the shape of the bearing edges to more of an oval curvature.
- the drive gear 32 is configured as a floating drive gear as it rotates to drive the driven gears.
- the drive gear is free to float radially relative to the driven gears.
- Such configuration permits the thickness of the sleeve bearings to be increased up to the maximum permitted by Equation (1), as the spaces between the drive shaft 38 and gear shafts 40 and 42 need not be allotted to providing a separate bearing structure for the drive gear.
- Figs. 4-6 are drawings depicting alternative configurations of the three-gear configuration 30 of Fig. 3 . Accordingly, like structures are afforded the same reference numerals in Figs. 4-6 as in Fig. 3 .
- Fig. 4 is a drawing that depicts a second exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention.
- the embodiment of Fig. 4 differs in the nature of the bearing structures provided for radially supporting the driven gears 34 and 36 for rotation of the driven gears about respective axes.
- the three-gear configuration of Fig. 4 includes bearing structures 52 and 54 positioned respectively adjacent to the driven gears 34 and 36.
- the bearing structures 52 and 54 are configured as sleeve bearing pairs, in which one sleeve bearing is provided on portions of the gear shafts 40 and 42 on opposite sides of the driven gear.
- the sleeve bearings 52 and 54 are fixed to the gears shafts 40 and 42. In such embodiment, therefore, the sleeve bearings rotate with the gears shafts as a unit relative to the pump housing structure.
- the configuration of Fig. 4 may be particularly suitable in applications when the housing is made of a non-metallic or other material that would tend to be softer than the gear material. With such configuration, the bearings rotate relative to the softer housing material, which results in less bearing wear than would tend to occur if the harder gear material rotated relative to the softer bearing material, as in the configuration of Fig. 3 .
- Fig. 5 is a drawing that depicts a third exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention.
- the embodiment of Fig. 5 differs in the nature of the bearing structure provided for radially supporting the driven gears 34 and 36.
- the bearing structure has bearings 56 and 58 positioned respectively adjacent to the driven gears 34 and 36.
- the bearing structures 56 and 58 are configured as a plurality of ball bearings that radially support the journals or gear shafts of the driven gears for rotation of the driven gears about respective axes.
- the ball bearings may be configured as ball bearing pairs, in which one ball bearing is provided on portions of the gear shafts 40 and 42 on opposite sides of the driven gear. Each ball bearing rotates within a ball bearing housing 60 or 61.
- the drive gear 32 of Fig. 5 also has a balanced load and is configured as a floating drive gear as it rotates to drive the driven gears. With such configuration, the outer diameters of the ball bearings may extend into spaces adjacent the drive gear 32 in accordance with Equation (1) to permit greater bearing loads.
- Fig. 6 is a drawing that depicts an exemplary assembly of a three-gear configuration and drive shaft for a three-gear pump system, in accordance with an embodiment of the present invention.
- the assembly of Fig. 6 include bearing structures adjacent to or associated with the driven gears, and a balanced load drive gear with no independent bearing structure. Accordingly, like structures are afforded the same reference numerals in Fig. 6 as in Figs. 3-5 .
- the assembly of Fig. 6 is depicted with bearing structures comparable to those of Fig. 3 . It will be appreciated, however, that any of the bearing structures of Figs. 3-5 may be employed in the assembly of Fig. 6 .
- Fig. 6 is a drawing that depicts an exemplary assembly of a three-gear configuration and drive shaft for a three-gear pump system, in accordance with embodiments of the present invention.
- the drive shaft 38 has a first end portion 62 that extends in a direction of a motor (not shown) that drives the drive shaft, and a driving portion 64 that extends into and drives the drive gear 32.
- the driving portion 64 is a spline portion that drives the drive gear, although alternative driving mechanisms, such as a keyway, may be employed.
- the driving or spline portion 64 cooperates with a reciprocal portion of the drive gear 32 to drive the drive gear.
- the driving portion 64 has a step configuration relative to the first end portion 62, such that the driving portion has a smaller outer diameter than the first end portion.
- the drive gear 32 has a reciprocal reverse step configuration for receiving the step configuration of the drive shaft. In this manner, the step configurations of the drive shaft and the drive gear act as a locator for easier positioning of the drive shaft properly with respect to the drive gear.
- Fig. 7 is a drawing that depicts an exemplary three-gear configuration 70 for a three-gear pump system in accordance with embodiments of the present invention, in which the drive gear has a larger diameter than a diameter of the driven gears.
- the three-gear configuration of Fig. 7 includes bearing structures adjacent to or associated with the driven gears, and a floating drive gear having a balanced load with no independent bearing structure. Accordingly, like structures are afforded the same reference numerals in Fig. 7 as in the previous figures.
- the three-gear configuration of Fig. 7 is depicted with bearing structures comparable to those of Fig. 3 . It will be appreciated, however, that any of the bearing structures of Figs. 3-5 may be employed in the three-gear configuration of Fig. 7 .
- Fig. 7 is taken at a side view of the three-gear configuration 70.
- the three-gear configuration 70 includes a center drive gear 72 that drives a first driven gear 34 and a second driven gear 36.
- the two driven gears are positioned on opposite sides of the drive gear 72 such that the axes of rotation of the three gears are parallel and aligned.
- the drive gear 72 is driven by the input shaft 38 that ultimately is driven by a motor (not shown).
- the drive gear 72 in turn drives the driven gears 34 and 36, which rotate respectively in conjunction with gear shafts 40 and 42.
- the rotation of the gears causes displacement of the fluid so as to pump fluid from an inlet side 44 to an outlet side 46.
- the drive gear 72 has an outer diameter that is greater than an outer diameter of the driven gears 34 and 36, as indicated by the lines/arrow in Fig. 7 .
- This configuration may be contrasted with the configuration of the previous embodiments, in which the drive gear 32 has the same outer diameter as the driven gears.
- An advantage of the greater drive gear diameter is that the permissible thickness or diameter of the bearings for the driven gears is increased. Specifically, the larger outer diameter of the center drive gear 72 in the embodiment of Fig. 7 increases the center distance value in Equation (1) above, which results in a greater maximum thickness of the bearings.
- the drive gear 72 also may have a greater number of gear teeth than the driven gears 34 and 36.
- the gear teeth of the drive gear are subject to more wear than the gear teeth of the driven gears.
- the number of gear teeth on the drive gear equals the number of teeth on the driven gears
- there are twice as many interactions by the drive gear teeth so the drive gear teeth may wear twice as much as the driven gear teeth.
- the number of interactions of the drive gear teeth is reduced, which commensurately reduces the amount of wear of the drive gear teeth relative to the amount of wear of the driven gear teeth.
- Fig. 8 is a drawing that depicts an exemplary three-gear arrangement that can be employed in the three-gear configuration of 70 of Fig. 7 .
- the center gear 72 has twelve gear teeth as compared to the nine gear teeth of the driven gears 34 and 36.
- Fig. 8 illustrates one non-limiting example, and the precise number of gear teeth in the drive and/or driven gears may be varied.
- the drive gear has twice as many gear teeth as the driven gears. Such configuration tends to equalize the gear teeth wear in the drive gear versus the driven gears by equalizing the number of gear teeth interactions.
- Another advantage of the increased drive gear diameter is in control of the running speed.
- a larger diameter drive gear will drive the driven gears at a higher running speed as compared to a smaller diameter drive gear.
- the higher speeds may result in an increased likelihood of building a hydrodynamic film to support loads on the driven gears.
- a drive gear running speed may be reduced for a larger diameter drive gear as compared to a smaller diameter drive gear. Reducing the running speed of the drive gear is particularly suitable for pump systems employing a brushless direct current (DC) electric motor as is known in the art, which are common in automotive and similar vehicle applications. Accordingly, the three-gear configuration in which the drive gear has a greater outer diameter than the driven gears provides a degree of flexibility in the control of the gear running speeds.
- DC direct current
- Fig. 9 is drawing that depicts an isometric view of an exemplary three-gear pump system 80 in accordance with embodiments of the present invention.
- Fig. 10 is a drawing that depicts a cross-sectional view of the exemplary three-gear pump system 80 of Fig. 9 .
- the pump system 80 includes a motor 82, a magnetic coupling 84, and a pump head 86 that includes or acts as a housing for the three-gear configurations.
- the motor may be a brushless DC electric motor as referenced above, although any suitable motor may be employed.
- the magnetic coupling 84 couples the pump head 86 to the motor 82, and the magnetic coupling further provides a barrier that prevents fluid from flowing from the pump head into the motor components.
- the pump head 86 includes an inlet 88 for receiving fluid being pumped, and an outlet 90 through which the pump fluid exits the pump head.
- the components of the three-gear configurations described above are housed within the pump head 86.
- the cross-sectional view of Fig. 10 further depicts components of the pump system 80, including the motor 82, magnetic coupling 84, and pump head 86.
- An exemplary three-gear configuration is shown as being enclosed within and/or housed within a housing 92 of the pump head 86.
- the pump head includes a center or drive gear 94 that is driven by a drive shaft 96 that drives the drive gear. At an end opposite the drive gear, the drive shaft 96 extends into the magnetic coupling 84.
- the magnetic coupling 84 is located between the motor 82 and the pump head 86, and transmits torque from the motor to the drive shaft 96 so as to drive the drive gear 94.
- the drive gear 94 in turn drives the driven gears 98 and 100.
- the drive gear and driven gears have essentially the same outer diameter, configurations comparable to the embodiments of Figs. 7 and 8 may be employed, in which the drive gear has a greater diameter than the driven gears.
- Journal bearing structures 102 and 104 are provided adjacent to or otherwise associated with the journals or shafts of the driven gears 98 and 100.
- the bearing structure configuration is shown to have a sleeve bearing configuration. It will be appreciated that the configuration of Fig. 10 is an example, and any of the bearing structure configurations comparable to any of the embodiments of Figs. 3-5 may be employed.
- the drive shaft 96 may be located and positioned relative to the drive gear 94 utilizing any of the structural components and configurations comparable to the embodiment of the assembly of Fig. 6 .
- the pump head 86 also may include a plate 106 located between the gears and the outlet 90, and enclosed by the housing 92. The plate 106 operates to provide axial pressure balance across the gears.
- an aspect of the invention is a three-gear pump system.
- the three-gear pump system includes a housing, and a three-gear configuration within the housing that pumps fluid from a fluid inlet to a fluid outlet.
- the three-gear configuration includes a center drive gear, a first driven gear, and a second driven gear positioned on opposite sides of the drive gear, and the drive gear meshes with the driven gears to drive the driven gears.
- the driven gears are radially supported within the housing by a bearing structure for rotation of the driven gears about respective axes, wherein the drive gear is free to float radially relative to the driven gears.
- the bearing structure comprises a plurality of sleeve bearings that support gear shafts of the driven gears.
- the plurality of sleeve bearings comprises sleeve bearing pairs positioned on portions of the gear shafts on opposite sides of the driven gears.
- the sleeve bearings are pressed into a pump housing and the driven gear shafts rotate relative to the sleeve bearings.
- the sleeve bearings are fixed to the gear shafts of the driven gears and the gear shafts and sleeve bearings rotate as a unit.
- the bearing structure comprises a plurality of ball bearings that support gear shafts of the driven gears.
- the plurality of ball bearings comprises ball bearing pairs positioned on portions of the gear shafts on opposite sides of the driven gears.
- each ball bearing rotates within a ball bearing housing.
- each ball bearing has an outer diameter that extends into a space adjacent the drive gear.
- the system further includes a drive shaft that has a driving portion that drives the drive gear.
- the driving portion of the drive shaft has a step configuration that acts as a locator to position the drive shaft relative to a reciprocal reverse step configuration of the drive gear.
- the system further includes a pin that is pressed into a housing of the pump system and extends into the reverse step configuration of the drive gear to locate the drive gear within the pump housing, and the drive shaft is inserted through the pin to locate the drive shaft relative to the drive gear.
- the system further includes a pin that is pressed into a housing of the pump system, and the pin extends into a reverse step configuration of the drive gear to locate the drive gear within the pump housing.
- the drive gear has a larger diameter than a diameter of the driven gears.
- the drive gear has a greater number of gear teeth than the driven gears.
- the drive gear has twice as many gear teeth as the driven gears.
- the system includes a pump head including the housing that houses the three-gear configuration and includes the fluid inlet and the fluid outlet, a drive shaft that drives the drive gear, a motor, and a magnetic coupling that is located between the motor and the pump head and transmits torque from the motor to the drive shaft.
- the system includes a housing, and a three-gear configuration within the housing that pumps fluid from a fluid inlet to a fluid outlet.
- the three-gear configuration includes a center drive gear, a first driven gear, and a second driven gear positioned on opposite sides of the drive gear, and the drive gear meshes with the driven gears to drive the driven gears.
- the driven gears are radially supported within the housing by a bearing for rotation of the driven gears about respective axes, wherein the drive gear has a larger diameter than a diameter of the driven gears.
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Description
- This application claims priority to
U.S. Provisional Patent Application Serial No. 61/949,414, filed on March 7, 2014 - The present application relates generally to fluid pump systems, and more particularly to fluid pump systems and multi-gear configurations for fluid pump systems configured for use with low viscosity fluids.
- Pump systems for low viscosity fluids are used in numerous applications. For example, low viscosity oils are commonly used in various diesel engine systems for construction and transportation vehicles. Methanol or ethanol based fuel systems, including for example jet fuel systems and high performance vehicle systems, also incorporate pumps in their fuel systems. Pump efficiency is particularly significant for low viscosity fluids such as those utilized in the referenced exemplary applications. Low viscosity fluids tend to flow more readily, and thus can leak or otherwise flow into undesirable areas of the system if not pumped efficiently. The advantage of the three-gear pump in improving volumetric efficiency by reducing leakage is described in
US2008/0056926 A1 . This problem is exacerbated when high outlet pressure is required of the pump. - Low-viscosity fluid pump systems, as referenced above, commonly are used in vehicle and transportation systems. Pumps in such applications therefore must be compact. It is difficult to design a pump that is sufficiently compact, and yet still handle the loads associated with the high pressures and flows particularly required for low-viscosity fluid applications.
- Multi-gear pumps may be utilized in such systems, which have an advantage of reduced gear facewidth per unit of displacement, so as to permit a lower shaft load per gear at a given pump displacement and running speed. Many conventional configurations use a two-gear pump, including a drive gear and a driven gear. Three-gear pumps have been employed, in which a center or drive gear drives two opposite driven gears to pump the fluid. Such three-gear pumps have an advantage in that the drive gear load tends to be balanced by two high-pressure and two low-pressure ports located diagonally opposite to each other adjacent the driven gears. This configuration enhances the load carrying capability of the pump, but supporting loads on the two driven gears is still of concern.
- In addition, for efficient operation it is required to build up a hydrodynamic journal film over the journals or shafts of the pump gears at the running conditions of the pump. The film results in minimal direct surface-to-surface contact of the pump components, and particularly the gear journals against the corresponding bearings, which reduces friction and wear. Maintaining a hydrodynamic journal film is more difficult for low viscosity fluids, which flow more readily out of the journal areas of the pump. Increasing the running speeds of the driven gear or gears can enhance the creation of the hydrodynamic journal film.
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EP 2055954 A1 discloses a double gear pump having a drive gear, two driven gears, a first bearing that supports a drive shaft of the drive gear and a second and a third bearings that support rotating shafts of the two driven gears, wherein the bearing length of the first bearing is shorter than the bearing lengths of the second and third bearings. - In view of the deficiencies of conventional low viscosity fluid pump systems, a need exists in the art for an improved three-gear pump system that is compact, while accommodating the requisite bearing structures. The present invention is a three-gear pump system in which the driven gears have an enhanced bearing structure, and the center or drive gear need not have a robust bearing support structure. As a result, the bearing structures supporting the driven gears can be enlarged relative to conventional configurations, which permits higher bearing loads to be carried.
- An aspect of the invention, therefore, is a three-gear pump system. In exemplary embodiments, the three-gear pump system includes a housing and a three-gear configuration within the housing that pumps fluid from one or two fluid inlets to one or two fluid outlets. The three-gear configuration includes a center drive gear, a first driven gear and a second driven gear positioned on opposite sides of the drive gear. The drive gear meshes with the driven gears to drive the driven gears, and the driven gears are radially supported within the housing by a bearing structure for rotation of the driven gears about respective axes. The balanced radial loads on the drive gear eliminate the need for bearing support of the drive gear, which is free to float relative to the driven gears.
- The drive gear may have a larger diameter and a greater number of gear teeth as compared to the driven gears. The pump system may include a pump head that houses the three-gear configuration, a motor, and a magnetic coupling that transmits torque from the motor to a drive shaft that drives the drive gear. The three-gear pump system particularly is suitable for pumping a low viscosity fluids at high pressures and running speeds.
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Fig. 1 is a drawing that depicts an exemplary conventional two-gear arrangement of gears for a two-gear pump system. -
Fig. 2 is a drawing that depicts an exemplary three-gear arrangement of gears for a three-gear pump system in accordance with embodiments of the present invention. -
Fig. 3 is a drawing that depicts a first exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention. -
Fig. 4 is a drawing that depicts a second exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention. -
Fig. 5 is a drawing that depicts a third exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention. -
Fig. 6 is a drawing that depicts an exemplary assembly of a three-gear configuration and drive shaft for a three-gear pump system, in accordance with embodiments of the present invention. -
Fig. 7 is a drawing that depicts an exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention, in which the drive gear has a larger outer diameter than the driven gears. -
Fig. 8 is a drawing that depicts an exemplary three-gear arrangement of gears for a three-gear pump system from a gear facing view in accordance with embodiments of the present invention, in which the drive gear has a larger outer diameter than the outer diameters of the driven gears. -
Fig. 9 is drawing that depicts an isometric view of an exemplary three-gear pump system in accordance with embodiments of the present invention. -
Fig. 10 is a drawing that depicts a cross-sectional view of the exemplary three-gear pump system ofFig. 9 . - Embodiments of the present invention will now be described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. It will be understood that the figures are not necessarily to scale.
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Fig. 1 is a drawing that depicts an exemplary conventional two-gear arrangement 10 of gears for a two-gear pump system.Fig. 1 depicts the limitations of a two-gear configuration with respect to bearing size and the resultant bearing load capability. As seen inFig. 1 , afirst gear 12 may be a drive gear that drives a second or drivengear 14. The gears may be spur gears by which the drive gear drives the driven gear via interacting or meshing gear teeth as is known in the art. As is commonly referred to in the art, a center distance is deemed to be the distance between the rotating axes of the gears. In addition, as denoted inFig. 1 by the parallel lines and arrows, a wall thickness is a distance between the bearing pockets of the two gears. With such a configuration, a maximum thickness of a bearing to support the gear shafts or journals is the difference between the center distance and the wall thickness. If ball bearings are employed as the bearing structure, the maximum distance would correspond to a maximum outer diameter of the ball bearings. The resultant maximum distance or outer ball bearing diameter is less than the pitch diameter of the gears in the two-gear arrangement ofFig. 1 . -
Fig. 2 is a drawing that depicts an exemplary three-gear arrangement 20 of gears for a three-gear pump system in accordance with embodiments of the present invention.Fig. 2 demonstrates that an enlarged bearing size can be utilized with a three-gear arrangement as compared to a two-gear arrangement. With the enlarged bearing size, bearings are capable of carrying higher loads. Referring toFig. 2 , the three-gear arrangement 20 includes acenter drive gear 22 that drives a first drivengear 24 and a second drivengear 26. The two driven gears are positioned on opposite sides of the drive gear such that the axes of rotation of the three gears are aligned. As in the two-gear configuration, the gears in the three-gear configuration may be spur gears by which the drive gear drives the driven gears via interacting or meshing gear teeth as is known in the art. In the case of a three-gear arrangement, the maximum thickness of the bearings for the driven gears (the maximum thickness being the maximum outer diameter when ball bears are employed) is equal to twice the difference of the center distance between the axes of rotation of the drive gear and the driven gears, minus the drive shaft outer diameter and the wall thickness (again denoted by the parallel lines and arrows inFig. 2 ), as set forth in Equation (1):Fig. 1 . - In accordance with the present invention, therefore, a three-gear pump system configuration is provided in which the driven gears are each supported by a bearing structure having a thickness up to the maximum as determined by Equation (1). In addition, the load on the center or drive gear is balanced to near zero by the positioning of the two driven gears. The drive gear acts as an overhung load driven by a drive shaft mechanism, such as for example a keyway or spline. Accordingly, the drive gear can rotate freely between the driven gears without any separate bearing structure for the drive gear. As referred to herein, because the drive gear is free to float radially relative to the driven gears without a separate or independent bearing structure, it is said to be a "floating drive gear" between the driven gears. With a floating drive gear, the thicknesses of the bearing structures for the driven gears can be increased to the maximum permitted by Equation (1), without any potential interference by a separate bearing structure for the drive gear. In the present invention, therefore, the bearing structures for the driven gears are further enhanced as compared to conventional configurations in which the drive gear typically is provided with its own support bearing.
- In exemplary embodiments, a three-gear pump system includes a housing and a three-gear configuration within the housing that pumps fluid from a fluid inlet to a fluid outlet. The three-gear configuration includes a center drive gear, and a first driven gear and a second driven gear positioned on opposite sides of the drive gear. The drive gear meshes with the driven gears to drive the driven gears, and the driven gears are radially supported within the housing by a bearing structure for rotation of the driven gears about respective axes. The drive gear is free to float radially relative to the driven gears.
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Fig. 3 is a drawing that depicts a first exemplary three-gear configuration 30 for a three-gear pump system in accordance with embodiments of the present invention.Fig. 3 is taken at a side view of the three-gear configuration. Similarly to the configuration depicted inFig. 2 , the three-gear configuration 30 includes acenter drive gear 32 that drives a first drivengear 34 and a second drivengear 36. The two driven gears are positioned on opposite sides of the drive gear such that the axes of rotation of the three gears are parallel and aligned. Thedrive gear 32 is driven by adrive shaft 38 that ultimately is driven by a motor (not shown). Thedrive gear 32 in turn drives the driven gears 34 and 36, which rotate respectively in conjunction withgear shafts inlet side 44 to anoutlet side 46. - The three-
gear configuration 30 further has a bearing structure that includesbearings Fig. 3 , the bearingstructures gear shafts Fig. 3 , the sleeve bearings may be pressed into a surrounding pump housing of the pump system. In such embodiment, therefore, the sleeve bearings remain fixed and thus do not rotate, with the shafts of the driven gears rotating relative to the sleeve bearings. - In exemplary embodiments, the gears may be formed of a rigid metallic material, such as stainless steel or other suitable metals. The sleeve bearings may be formed of a rigid polymer or any suitable bearing grade plastic material as are known in the art. As such, the bearings tend to be softer than the gears, and bearing wear is a concern. Bearing wear changes the shape of the bearing edges to more of an oval curvature.
- In addition, as referenced above, the
drive gear 32 is configured as a floating drive gear as it rotates to drive the driven gears. In other words, because the load on the drive gear is balanced by the positioning of the drive gear between the driven gears, the drive gear is free to float radially relative to the driven gears. There is no separate or independent bearing structure associated with radially supporting the drive gear. Such configuration permits the thickness of the sleeve bearings to be increased up to the maximum permitted by Equation (1), as the spaces between thedrive shaft 38 andgear shafts -
Figs. 4-6 are drawings depicting alternative configurations of the three-gear configuration 30 ofFig. 3 . Accordingly, like structures are afforded the same reference numerals inFigs. 4-6 as inFig. 3 . -
Fig. 4 is a drawing that depicts a second exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention. The embodiment ofFig. 4 differs in the nature of the bearing structures provided for radially supporting the driven gears 34 and 36 for rotation of the driven gears about respective axes. In particular, the three-gear configuration ofFig. 4 includes bearingstructures Fig. 4 , the bearingstructures gear shafts - In the embodiment of
Fig. 4 , in contrast to the embodiment ofFig. 3 , thesleeve bearings gears shafts Fig. 4 may be particularly suitable in applications when the housing is made of a non-metallic or other material that would tend to be softer than the gear material. With such configuration, the bearings rotate relative to the softer housing material, which results in less bearing wear than would tend to occur if the harder gear material rotated relative to the softer bearing material, as in the configuration ofFig. 3 . Thedrive gear 32 ofFig. 4 also is configured as a floating drive gear as it rotates to drive the driven gears. In other words, the load on the drive gear is balanced and the drive gear is free to float radially relative to the driven gears. There again is no separate or independent bearing structure associated with radially supporting the drive gear. -
Fig. 5 is a drawing that depicts a third exemplary three-gear configuration for a three-gear pump system in accordance with embodiments of the present invention. The embodiment ofFig. 5 differs in the nature of the bearing structure provided for radially supporting the driven gears 34 and 36. In particular, in the three-gear configuration ofFig. 5 , the bearing structure hasbearings Fig. 5 , the bearingstructures gear shafts ball bearing housing drive gear 32 ofFig. 5 also has a balanced load and is configured as a floating drive gear as it rotates to drive the driven gears. With such configuration, the outer diameters of the ball bearings may extend into spaces adjacent thedrive gear 32 in accordance with Equation (1) to permit greater bearing loads. -
Fig. 6 is a drawing that depicts an exemplary assembly of a three-gear configuration and drive shaft for a three-gear pump system, in accordance with an embodiment of the present invention. As in the previous embodiments, the assembly ofFig. 6 include bearing structures adjacent to or associated with the driven gears, and a balanced load drive gear with no independent bearing structure. Accordingly, like structures are afforded the same reference numerals inFig. 6 as inFigs. 3-5 . In addition, for illustrative purposes, the assembly ofFig. 6 is depicted with bearing structures comparable to those ofFig. 3 . It will be appreciated, however, that any of the bearing structures ofFigs. 3-5 may be employed in the assembly ofFig. 6 . -
Fig. 6 is a drawing that depicts an exemplary assembly of a three-gear configuration and drive shaft for a three-gear pump system, in accordance with embodiments of the present invention. Thedrive shaft 38 has afirst end portion 62 that extends in a direction of a motor (not shown) that drives the drive shaft, and a drivingportion 64 that extends into and drives thedrive gear 32. In exemplary embodiments, the drivingportion 64 is a spline portion that drives the drive gear, although alternative driving mechanisms, such as a keyway, may be employed. The driving orspline portion 64 cooperates with a reciprocal portion of thedrive gear 32 to drive the drive gear. The drivingportion 64 has a step configuration relative to thefirst end portion 62, such that the driving portion has a smaller outer diameter than the first end portion. Thedrive gear 32 has a reciprocal reverse step configuration for receiving the step configuration of the drive shaft. In this manner, the step configurations of the drive shaft and the drive gear act as a locator for easier positioning of the drive shaft properly with respect to the drive gear. -
Fig. 7 is a drawing that depicts an exemplary three-gear configuration 70 for a three-gear pump system in accordance with embodiments of the present invention, in which the drive gear has a larger diameter than a diameter of the driven gears. As in the previous embodiments, the three-gear configuration ofFig. 7 includes bearing structures adjacent to or associated with the driven gears, and a floating drive gear having a balanced load with no independent bearing structure. Accordingly, like structures are afforded the same reference numerals inFig. 7 as in the previous figures. In addition, for illustrative purposes, the three-gear configuration ofFig. 7 is depicted with bearing structures comparable to those ofFig. 3 . It will be appreciated, however, that any of the bearing structures ofFigs. 3-5 may be employed in the three-gear configuration ofFig. 7 . -
Fig. 7 is taken at a side view of the three-gear configuration 70. Similarly to the configuration depicted in the previous figures the three-gear configuration 70 includes acenter drive gear 72 that drives a first drivengear 34 and a second drivengear 36. The two driven gears are positioned on opposite sides of thedrive gear 72 such that the axes of rotation of the three gears are parallel and aligned. Thedrive gear 72 is driven by theinput shaft 38 that ultimately is driven by a motor (not shown). Thedrive gear 72 in turn drives the driven gears 34 and 36, which rotate respectively in conjunction withgear shafts inlet side 44 to anoutlet side 46. - In the embodiment of
Fig. 7 , thedrive gear 72 has an outer diameter that is greater than an outer diameter of the driven gears 34 and 36, as indicated by the lines/arrow inFig. 7 . This configuration may be contrasted with the configuration of the previous embodiments, in which thedrive gear 32 has the same outer diameter as the driven gears. An advantage of the greater drive gear diameter is that the permissible thickness or diameter of the bearings for the driven gears is increased. Specifically, the larger outer diameter of thecenter drive gear 72 in the embodiment ofFig. 7 increases the center distance value in Equation (1) above, which results in a greater maximum thickness of the bearings. - Relatedly, in view of the greater outer diameter, the
drive gear 72 also may have a greater number of gear teeth than the driven gears 34 and 36. In general, because the center drive gear teeth interact with the gear teeth of both driven gears, the gear teeth of the drive gear are subject to more wear than the gear teeth of the driven gears. For example, when the number of gear teeth on the drive gear equals the number of teeth on the driven gears, there are twice as many interactions by the drive gear teeth so the drive gear teeth may wear twice as much as the driven gear teeth. By increasing the outer diameter and number of teeth of the drive gear, the number of interactions of the drive gear teeth is reduced, which commensurately reduces the amount of wear of the drive gear teeth relative to the amount of wear of the driven gear teeth. -
Fig. 8 is a drawing that depicts an exemplary three-gear arrangement that can be employed in the three-gear configuration of 70 ofFig. 7 . In the example ofFig. 8 , thecenter gear 72 has twelve gear teeth as compared to the nine gear teeth of the driven gears 34 and 36. It will be appreciated thatFig. 8 illustrates one non-limiting example, and the precise number of gear teeth in the drive and/or driven gears may be varied. In one embodiment, the drive gear has twice as many gear teeth as the driven gears. Such configuration tends to equalize the gear teeth wear in the drive gear versus the driven gears by equalizing the number of gear teeth interactions. - Another advantage of the increased drive gear diameter is in control of the running speed. For a given drive gear running speed, a larger diameter drive gear will drive the driven gears at a higher running speed as compared to a smaller diameter drive gear. The higher speeds may result in an increased likelihood of building a hydrodynamic film to support loads on the driven gears. Stated in another way, to maintain a given running speed of the driven gears, a drive gear running speed may be reduced for a larger diameter drive gear as compared to a smaller diameter drive gear. Reducing the running speed of the drive gear is particularly suitable for pump systems employing a brushless direct current (DC) electric motor as is known in the art, which are common in automotive and similar vehicle applications. Accordingly, the three-gear configuration in which the drive gear has a greater outer diameter than the driven gears provides a degree of flexibility in the control of the gear running speeds.
- The various embodiments of the three-gear configurations described above may be employed in a pump system, and a low-viscosity fluid pump system in particular.
Fig. 9 is drawing that depicts an isometric view of an exemplary three-gear pump system 80 in accordance with embodiments of the present invention.Fig. 10 is a drawing that depicts a cross-sectional view of the exemplary three-gear pump system 80 ofFig. 9 . - Referring first to
Fig. 9 , thepump system 80 includes amotor 82, amagnetic coupling 84, and apump head 86 that includes or acts as a housing for the three-gear configurations. The motor may be a brushless DC electric motor as referenced above, although any suitable motor may be employed. Themagnetic coupling 84 couples thepump head 86 to themotor 82, and the magnetic coupling further provides a barrier that prevents fluid from flowing from the pump head into the motor components. Thepump head 86 includes aninlet 88 for receiving fluid being pumped, and anoutlet 90 through which the pump fluid exits the pump head. The components of the three-gear configurations described above are housed within thepump head 86. - The cross-sectional view of
Fig. 10 further depicts components of thepump system 80, including themotor 82,magnetic coupling 84, and pumphead 86. An exemplary three-gear configuration is shown as being enclosed within and/or housed within ahousing 92 of thepump head 86. The pump head includes a center or drivegear 94 that is driven by adrive shaft 96 that drives the drive gear. At an end opposite the drive gear, thedrive shaft 96 extends into themagnetic coupling 84. Themagnetic coupling 84 is located between themotor 82 and thepump head 86, and transmits torque from the motor to thedrive shaft 96 so as to drive thedrive gear 94. Thedrive gear 94 in turn drives the driven gears 98 and 100. Although in the example ofFig. 10 the drive gear and driven gears have essentially the same outer diameter, configurations comparable to the embodiments ofFigs. 7 and 8 may be employed, in which the drive gear has a greater diameter than the driven gears. -
Journal bearing structures Fig. 10 , the bearing structure configuration is shown to have a sleeve bearing configuration. It will be appreciated that the configuration ofFig. 10 is an example, and any of the bearing structure configurations comparable to any of the embodiments ofFigs. 3-5 may be employed. Similarly, thedrive shaft 96 may be located and positioned relative to thedrive gear 94 utilizing any of the structural components and configurations comparable to the embodiment of the assembly ofFig. 6 . Thepump head 86 also may include aplate 106 located between the gears and theoutlet 90, and enclosed by thehousing 92. Theplate 106 operates to provide axial pressure balance across the gears. - In accordance with the above, an aspect of the invention is a three-gear pump system. In exemplary embodiments, the three-gear pump system includes a housing, and a three-gear configuration within the housing that pumps fluid from a fluid inlet to a fluid outlet. The three-gear configuration includes a center drive gear, a first driven gear, and a second driven gear positioned on opposite sides of the drive gear, and the drive gear meshes with the driven gears to drive the driven gears. The driven gears are radially supported within the housing by a bearing structure for rotation of the driven gears about respective axes, wherein the drive gear is free to float radially relative to the driven gears.
- In an exemplary embodiment of the three-gear pump system, the bearing structure comprises a plurality of sleeve bearings that support gear shafts of the driven gears.
- In an exemplary embodiment of the three-gear pump system, the plurality of sleeve bearings comprises sleeve bearing pairs positioned on portions of the gear shafts on opposite sides of the driven gears.
- In an exemplary embodiment of the three-gear pump system, the sleeve bearings are pressed into a pump housing and the driven gear shafts rotate relative to the sleeve bearings.
- In an exemplary embodiment of the three-gear pump system, the sleeve bearings are fixed to the gear shafts of the driven gears and the gear shafts and sleeve bearings rotate as a unit.
- In an exemplary embodiment of the three-gear pump system, a maximum thickness of each sleeve bearing is set forth by the equation:
- In an exemplary embodiment of the three-gear pump system, the bearing structure comprises a plurality of ball bearings that support gear shafts of the driven gears.
- In an exemplary embodiment of the three-gear pump system, the plurality of ball bearings comprises ball bearing pairs positioned on portions of the gear shafts on opposite sides of the driven gears.
- In an exemplary embodiment of the three-gear pump system, each ball bearing rotates within a ball bearing housing.
- In an exemplary embodiment of the three-gear pump system, each ball bearing has an outer diameter that extends into a space adjacent the drive gear.
- In an exemplary embodiment of the three-gear pump system, a maximum outer diameter of each ball bearing is set forth by the equation:
- In an exemplary embodiment of the three-gear pump system, the system further includes a drive shaft that has a driving portion that drives the drive gear.
- In an exemplary embodiment of the three-gear pump system, the driving portion of the drive shaft has a step configuration that acts as a locator to position the drive shaft relative to a reciprocal reverse step configuration of the drive gear.
- In an exemplary embodiment of the three-gear pump system, the system further includes a pin that is pressed into a housing of the pump system and extends into the reverse step configuration of the drive gear to locate the drive gear within the pump housing, and the drive shaft is inserted through the pin to locate the drive shaft relative to the drive gear.
- In an exemplary embodiment of the three-gear pump system, the system further includes a pin that is pressed into a housing of the pump system, and the pin extends into a reverse step configuration of the drive gear to locate the drive gear within the pump housing.
- In an exemplary embodiment of the three-gear pump system, the drive gear has a larger diameter than a diameter of the driven gears.
- In an exemplary embodiment of the three-gear pump system, the drive gear has a greater number of gear teeth than the driven gears.
- In an exemplary embodiment of the three-gear pump system, the drive gear has twice as many gear teeth as the driven gears.
- In an exemplary embodiment of the three-gear pump system, the system includes a pump head including the housing that houses the three-gear configuration and includes the fluid inlet and the fluid outlet, a drive shaft that drives the drive gear, a motor, and a magnetic coupling that is located between the motor and the pump head and transmits torque from the motor to the drive shaft.
- In an exemplary embodiment of the three-gear pump system, the system includes a housing, and a three-gear configuration within the housing that pumps fluid from a fluid inlet to a fluid outlet. The three-gear configuration includes a center drive gear, a first driven gear, and a second driven gear positioned on opposite sides of the drive gear, and the drive gear meshes with the driven gears to drive the driven gears. The driven gears are radially supported within the housing by a bearing for rotation of the driven gears about respective axes, wherein the drive gear has a larger diameter than a diameter of the driven gears.
Claims (17)
- A three-gear pump system comprising:a housing;a three-gear configuration (20) within the housing that pumps fluid from a fluid inlet to a fluid outlet, the three-gear configuration comprising:a center drive gear (22);a first driven gear (24) and a second driven gear (26) positioned on opposite sides of the drive gear, and the drive gear meshes with the driven gears to drive the driven gears; andthe driven gears are radially supported within the housing by a bearing structure for rotation of the driven gears about respective axes; and characterised in that the drive gear is free to float radially relative to the driven gears.
- The three-gear pump system of claim 1, wherein the bearing structure comprises a plurality of sleeve bearings(48, 50) that support gear shafts (40, 42) of the driven gears.
- The three-gear pump system of claim 2, wherein the plurality of sleeve bearings comprises sleeve bearing pairs (52, 54) positioned on portions of the gear shafts (40, 42) on opposite sides of the driven gears.
- The three-gear pump system of any of claims 2-3, wherein the sleeve bearings are pressed into a pump housing and the driven gear shafts rotate relative to the sleeve bearings.
- The three-gear pump system of any of claims 2-3, wherein the sleeve bearings are fixed to the gear shafts of the driven gears and the gear shafts and sleeve bearings rotate as a unit.
- The three-gear system of any of claims 2-5, wherein a maximum thickness of each sleeve bearing is set forth by the equation:
- The three-gear pump system of claim 1, wherein the bearing structure comprises a plurality of ball bearings (56, 58) that support gear shafts of the driven gears.
- The three-gear pump system of claim 7, wherein the plurality of ball bearings comprises ball bearing pairs positioned on portions of the gear shafts on opposite sides of the driven gears.
- The three-gear pump system of any of claims 7-8, wherein each ball bearing (56, 58) rotates within a ball bearing housing (60, 61).
- The three-gear pump system of any of claims 7-9, wherein each ball bearing has an outer diameter that extends into a space adjacent the drive gear.
- The three-gear pump system of any of claims 7-10, wherein a maximum outer diameter of each ball bearing is set forth by the equation:
- The three-gear pump system of any of claims 1-11, further comprising a drive shaft (38) that has a driving portion (64) that drives the drive gear.
- The three-gear pump system of claim 12, wherein the driving portion of the drive shaft has a step configuration that acts as a locator to position the drive shaft relative to a reciprocal reverse step configuration of the drive gear (32).
- The three-gear pump system of any of claims 1 - 13, wherein the drive gear has a larger diameter than a diameter of the driven gears.
- The three-gear pump system of claim 14, wherein the drive gear (72) has a greater number of gear teeth than the driven gears (34, 36).
- The three-gear pump system of claim 15, wherein the drive gear has twice as many gear teeth as the driven gears.
- The three-gear pump system (80) of any of claims 11 - 16 comprising:a pump head (86) including the housing (92) that houses the three-gear configuration and includes the fluid inlet and the fluid outlet;a drive shaft (96) that drives the drive gear (94);a motor (82); anda magnetic coupling (84) that is located between the motor and the pump head and transmits torque from the motor to the drive shaft.
Applications Claiming Priority (2)
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US201461949414P | 2014-03-07 | 2014-03-07 | |
PCT/US2015/016530 WO2015134194A1 (en) | 2014-03-07 | 2015-02-19 | Three-gear pump system for low viscosity fluids |
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EP3114350A1 EP3114350A1 (en) | 2017-01-11 |
EP3114350B1 true EP3114350B1 (en) | 2021-06-30 |
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EP15707497.2A Active EP3114350B1 (en) | 2014-03-07 | 2015-02-19 | Three-gear pump system for low viscosity fluids |
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WO (1) | WO2015134194A1 (en) |
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DE102016216159A1 (en) * | 2016-08-29 | 2018-03-01 | Robert Bosch Gmbh | External gear pump for a waste heat recovery system |
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US4184808A (en) * | 1977-11-09 | 1980-01-22 | Caterpillar Tractor Co. | Fluid driven pump |
US4386893A (en) * | 1981-05-04 | 1983-06-07 | Deere & Company | Gear pump or motor with a shaftless gear |
US6205779B1 (en) * | 1999-03-31 | 2001-03-27 | Daimlerchrysler Corporation | Integral hub driven gears |
JP5040214B2 (en) * | 2006-08-23 | 2012-10-03 | 株式会社Ihi | Triple gear pump |
US7591640B2 (en) | 2006-08-30 | 2009-09-22 | Ishikawajima-Harima Heavy Industries Co., Ltd. | Three gear type gear pump of a fuel supply system |
-
2015
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