The present disclosure relates generally to a gerotor pump, and more specifically to a split power gerotor pump.
Gerotor pumps with integrated motors are shown in United States Patent Application Publication Nos. 2017/328,362 titled INTEGRATED ECCENTRIC MOTOR AND PUMP and 2019/301,456 titled INTEGRATED MOTOR AND PUMP INCLUDING RADIALLY MOVABLE OUTER GERATOR, both of which are hereby incorporated by reference as if set forth fully herein.
Example aspects broadly comprise a gerotor pump including an inner gerotor, a wobble cancellation element, and an outer gerotor disposed radially between the inner gerotor and the wobble cancellation element. The inner gerotor includes a first rotational axis and a first outer peripheral surface. The first outer peripheral surface includes n first lobes equally spaced from one another in a circumferential direction, and n first depressions, each disposed between an adjacent pair of first lobes. The wobble cancellation element includes a second rotational axis aligned with the first rotational axis such that the inner gerotor and the wobble cancellation element are coaxial, and a first inner peripheral surface. The first inner peripheral surface includes n+1 second lobes equally spaced from one another in the circumferential direction, and n+1 arcuate surfaces, each arranged between an adjacent pair of second lobes. The outer gerotor includes a second outer peripheral surface including n+1 outer depressions complementary to and arranged to engage the second lobes, and a second inner peripheral surface comprising n+1 inner depressions complementary to and arranged to engage the first lobes.
In an example embodiment, each of the outer depressions of the outer gerotor remains aligned with a same second lobe of the wobble cancellation element when the inner gerotor is rotated relative to the wobble cancellation element. In an example embodiment, each of the inner depressions of the outer gerotor translates between different first lobes of the inner gerotor when the inner gerotor is rotated relative to the wobble cancellation element. In an example embodiment, the outer gerotor is free to float between the inner gerotor and the wobble cancellation element. In an example embodiment, during operation of the gerotor pump, the outer gerotor translates rotationally when the wobble cancellation element is rotated and the inner gerotor is fixed, and the outer gerotor moves but does not translate rotationally when the inner gerotor is rotated and the wobble cancellation element is fixed.
In some example embodiments, the inner gerotor includes a first swash plate with a first radial wall that radially overlaps the second lobes and the arcuate surfaces of the wobble cancellation element, and n first fluid ports disposed in the first radial wall, each one of the n first fluid ports radially aligned with a one of the first lobes. In some example embodiments, the inner gerotor includes a second swash plate with a second radial wall that radially overlaps the second lobes and the arcuate surfaces of the wobble cancellation element, and n second fluid ports each radially aligned with a one of the first depressions. In an example embodiment, the outer gerotor has n+1 third lobes, each aligned with an outer depression, and, when an adjacent pair of first depressions is aligned with an adjacent pair of third lobes, the outer gerotor entirely covers a one of the first fluid ports.
In some example embodiments, the first swash plate is disposed on a first axial side of the outer gerotor and the wobble cancellation element, and the second swash plate is disposed on a second axial side of the outer gerotor and the wobble cancellation element, opposite the first axial side. In an example embodiment, the gerotor pump is arranged to pump a fluid from the first fluid ports to the second fluid ports, or vice versa, when the outer gerotor is displaced relative to the inner gerotor.
In some example embodiments, the inner gerotor includes a first gear for driving engagement by a one of an internal combustion engine or an electric motor. In an example embodiment, the wobble cancellation element includes a second gear arranged for driving engagement by the other of the internal combustion engine or the electric motor. In an example embodiment, the gerotor pump includes a first bearing disposed radially between the inner gerotor and the wobble cancellation element. In an example embodiment, the gerotor pump includes a housing enclosing the inner gerotor, the wobble cancellation element, and the outer gerotor, a second bearing disposed radially between the inner gerotor and the outer gerotor, and a third bearing, axially offset from the second bearing and disposed radially between the housing and the inner gerotor.
In some example embodiments, the inner gerotor includes a first hollow shaft. In some example embodiments, the wobble cancellation element includes a distributor, and the distributor includes a second hollow shaft coaxial with the first hollow shaft. In an example embodiment, the gerotor pump includes a housing enclosing the inner gerotor, the wobble cancellation element, and the outer gerotor, and a fourth bearing disposed radially between the housing and the distributor.
In some example embodiments, the inner gerotor includes a first hollow shaft and a first swash plate. The first swash plate has a first radial wall that radially overlaps the second lobes and the arcuate surfaces of the wobble cancellation element, and n first fluid ports disposed in the first radial wall, each one of the n first fluid ports radially aligned with a one of the first lobes. The wobble cancellation element includes a distributor with a second hollow shaft coaxial with the first hollow shaft, and a second radial wall. The inner gerotor and the wobble cancellation element form at least a portion of a chamber for receiving a fluid, the distributor includes a plurality of radial holes fluidly connecting the second hollow shaft to the chamber, and the chamber is fluidly connected to the first fluid ports.
In some example embodiments, the gerotor pump includes a housing enclosing the inner gerotor, the wobble cancellation element, and the outer gerotor. The inner gerotor includes a second swash plate with a second radial wall that axially overlaps the second lobes and the arcuate surfaces of the wobble cancellation element, and n second fluid ports each radially aligned with a one of the first depressions. The housing includes a plurality of circumferential slots at least partially aligned with the second fluid ports. In an example embodiment, the housing includes a cover with a radial groove at least partially aligned with the first hollow shaft, and a circumferential groove at least partially aligned with the plurality of circumferential slots.
Embodiments of the present disclosure are described herein. It should be appreciated that like drawing numbers appearing in different drawing views identify identical, or functionally similar, structural elements. Also, it is to be understood that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
The terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the following example methods, devices, and materials are now described.
The following description is made with reference to
The wobble cancellation element includes rotational axis 26 aligned with rotational axis 18 such that the inner gerotor and the wobble cancellation element are coaxial. The wobble cancellation element also includes inner peripheral surface 28 including six lobes 30 equally spaced from one another in the circumferential direction and six arcuate surfaces 32, each arranged between an adjacent pair of lobes 30. Although six lobes and arcuate surfaces are shown, other numbers of lobes and arcuate surfaces are possible. For example, wobble cancellation element 16 may include five or seven lobes and arcuate surfaces. It should be noted that the number of lobes 22 is exactly one less than the number of lobes 30. In other words, if inner gerotor 12 has n lobes 22 then wobble cancellation element includes n+1 lobes 30.
The outer gerotor includes outer peripheral surface 34 including six outer depressions 36 complementary to and arranged to engage the lobes 30, inner peripheral surface 38 including six inner depressions 40 complementary to and arranged to engage lobes 22. Although six outer depressions and inner depressions are shown, other numbers are possible. For example, outer gerotor 16 may include five or seven outer depressions and inner depressions. For the example used above, the outer gerotor would have n+1 outer depressions and inner depressions, the same as the number of lobes 30 and arcuate surfaces for wobble cancellation element 14.
Each of the outer depressions of the outer gerotor remains aligned with a same lobe 30 of the wobble cancellation element when the inner gerotor is rotated relative to the wobble cancellation element. Each of the inner depressions of the outer gerotor translates between different lobes 22 of the inner gerotor when the inner gerotor is rotated relative to the wobble cancellation element. The outer gerotor is free to float between the inner gerotor and the wobble cancellation element. During operation of the gerotor pump, the outer gerotor translates rotationally when the wobble cancellation element is rotated and the inner gerotor is fixed, and the outer gerotor moves but does not translate rotationally when the inner gerotor is rotated and the wobble cancellation element is fixed.
The following description is made with reference to
Inner gerotor 110 includes swash plate 144 with radial wall 150 that radially overlaps lobes 130 and arcuate surfaces 132 of the wobble cancellation element, and five fluid ports 152 each radially aligned with a one of depressions 124. Swash plates 142 and 144 include respective bores 154 and 156 for receiving pins 158 (ref.
As best viewed in
The following description is made with reference to
Gerotor pump 110 includes bearing 168 is disposed radially between the inner gerotor and the wobble cancellation element. Gerotor pump 110 also includes housing 170 enclosing the inner gerotor, the wobble cancellation element, and the outer gerotor, bearing 172 disposed radially between the inner gerotor and the wobble cancellation element, and bearing 174, axially offset from bearing 172 and disposed radially between the housing and the inner gerotor.
Inner gerotor 112 includes hollow shaft 176. Wobble cancellation element 114 includes distributor 178 with hollow shaft 180 coaxial with hollow shaft 176. Bearing 182 is disposed radially between the housing and the distributor. Inner gerotor 112 and wobble cancellation element 114 form a portion of a chamber 184 for receiving a fluid. Distributor 178 includes radial holes 186 fluidly connecting hollow shaft 180 to the chamber. Chamber 184 is fluidly connected to fluid ports 148.
The following description is made with reference to
The following description is made with reference to
For useful, unidirectional flow to emerge, each volume must be exposed to only one of either the inlet or the outlet fluid. Swash plates provide a method for accomplishing this end. Each swash plate has holes cut through it so that fluid may enter or exit the corresponding expanding or contracting volumes. The geometry of the holes is such that the relative motion between the inner gerotor and outer gerotor uncovers or covers the ports so that either suction or pumping action can be formed. At any given time, all expanding volumes will be open to the inlet fluid, and all contracting volumes will be open to the outlet fluid. To keep the relative motion consistent between the inner and outer gerotors, ensuring proper porting, both swash plates rotate together.
The second mode of operation is similar to the first. Suction and pumping action is created through the same mechanism of expanding and contracting volumes created by the relative motion of the inner gerotor and the outer gerotor. However, for the second mode, the lobed ring rotates while the inner gerotor is held fixed. Again, the outer gerotor floats and is constrained axially and radially by the geometry of the inner gerotor and the lobed ring. As the lobed ring rotates, the outer gerotor is geometrically forced in a precession around the inner gerotor. Similar to the first mode, the outer gerotor translates in a circular path around the inner gerotor's rotational axis. However, this mode of operation also introduces a rotation of the outer gerotor about its own rotational axis equal to the same angular velocity as the lobed ring.
The third mode of operation is a superposition of the first two modes. In this mode, both the inner gerotor and the lobed ring are rotated while the outer gerotor floats. If the inner gerotor and lobed ring are rotated in opposite directions, the relative velocity between the outer gerotor and the inner gerotor increases, providing an increased fluid flow rate and a pump boost. Rotation of the inner gerotor and the lobed ring in the same direction, has the opposite effect.
Independent of operation mode, fluid enters and exits through separated channels in a cover adapted to the particular application. The cover's inlet channel connects to another channel cut through the inner gerotor's center. Eventually, the fluid runs into the distributor portion of the lobed ring. Holes in the distributor allow the fluid to enter the sealed suction chamber formed by the distributor, inner gerotor and lobed ring. Fluid is then drawn into and pumped through the gerotor section. The fluid then ends up in the sealed pressure chamber formed by the outlet swash plate and the housing. Holes in the housing permits fluid flow into the outlet channel of the cover for its final exit. The housing surrounds all of the moving components for safety and provides support for the structure.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the disclosure that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.
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Number | Date | Country | |
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20210048022 A1 | Feb 2021 | US |
Number | Date | Country | |
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62887750 | Aug 2019 | US |