Patent Description:
A gerotor pump may be used as a positive displacement pump. Typically, a gerotor includes an inner gear (or rotor) that meshes with an outer gear (rotor). The outer gear has greater number of teeth than the inner gear. The axis of the inner gear is offset from the axis of the outer gear and both gears rotate on their respective axes. The offset creates a changing-volume space between them. During a rotation cycle, fluid may enter a suction side of the gerotor, get pressurized due to the changing-volume space and the pressurized fluid is discharged at a discharge port of the gerotor. Such gerotors can experience several mechanical and frictional losses, and may be bulky.

<CIT> describes a multi-drive pump that may include a pump housing, an inlet port, an outlet port, a primary pump gear, a secondary pump gear, a first internal mechanical drive mechanism coupled to the primary pump gear and a second internal mechanical drive mechanism and an internal electro-magnetic drive mechanism coupled to the secondary pump gear. The pump housing may define an internal volume fluidly coupled to the inlet port and the outlet port. The primary pump gear and the secondary pump gear may be positioned in the pump housing and coupled to one another. Rotation of the primary pump gear and the secondary pump gear draws fluid into the inlet port and expels fluid from the outlet port. The primary pump gear may be rotated by the first internal mechanical drive mechanism and the secondary pump gear may be rotated by the second internal mechanical drive mechanism and the internal electro-magnetic drive mechanism.

<CIT> describes an electric pump that comprises a case in which a core being enwound by a coil is embedded, a permanent magnet formed in a cylindrical shape, having a central axis being identical to that of the core, and positioned so as to face an inner peripheral side of the core, an outer rotor fixed to an inner peripheral side of the permanent magnet, a rotor unit including the permanent magnet and the outer rotor, an inner rotor having a central axis, which is eccentric from a central axis of the core, so as to rotate; and an inscribed-type pump for carrying out, by means of rotation of the inner rotor, which is engaged with the outer rotor so as to rotate in accordance with rotation of the outer rotor, intake and exhaust of fluids, characterized in that the rotor unit includes a slide surface extending in an axial direction; the case includes a convex portion having an identical central axis to that of the core, and the rotor unit is rotatably supported by the peripheral surface of the convex portion at the slide surface.

An aspect of this invention provides a gerotor pump according to the appended claims.

Another aspect of this invention includes a system having the above-noted gerotor pump along with an engine or transmission.

The accompanying drawings have not necessarily been drawn to scale. Any values dimensions illustrated in the accompanying graphs and figures are for illustration purposes only and may or may not represent actual or preferred values or dimensions. Where applicable, some or all features may not be illustrated to assist in the description of underlying features. In the drawings:.

The description set forth below in connection with the appended drawings is intended as a description of various embodiments of the disclosed subject matter and is not necessarily intended to represent the only embodiment(s). In certain instances, the description includes specific details for the purpose of providing an understanding of the disclosed embodiment(s). However, it will be apparent to those skilled in the art that the disclosed embodiment(s) may be practiced without those specific details. In some instances, well-known structures and components may be shown in block diagram form in order to avoid obscuring the concepts of the disclosed subject matter.

Reference throughout the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. Further, it is intended that embodiments of the disclosed subject matter cover modifications and variations thereof.

It is to be understood that terms such as "top," "bottom," "side," "height," "upper," "lower," "interior," "exterior," "inner," "outer," and the like that may be used herein merely describe points of reference and do not necessarily limit embodiments of the present disclosure to any particular orientation or configuration. Furthermore, terms such as "first," "second," "third," etc., merely identify one of a number of portions, components, steps, operations, functions, and/or points of reference as disclosed herein, and likewise do not necessarily limit embodiments of the present disclosure to any particular configuration or orientation, or any requirement that each number must be included.

Also, the terms "fluid" and "lubricant" are used interchangeably throughout this disclosure and not intended to limit this disclosure in any way. In some embodiments, fluid or lubricant may refer to oil, e.g., such as engine oil. In other embodiments, fluid or lubricant may refer to transmission fluid.

<FIG> illustrate different perspective views of a gerotor pump <NUM> in accordance with an embodiment. The gerotor pump <NUM> includes a top cover <NUM> mounted to a bottom casing <NUM> to form a housing assembly <NUM> (also referred as a housing <NUM> or a gerotor housing <NUM> herein). The gerotor pump <NUM> also includes a set <NUM> of gerotor gears (e.g., an inner gear <NUM> and an outer gear <NUM> shown in <FIG>) enclosed in the housing <NUM>. The bottom casing <NUM> includes an input (or entry) port <NUM> through which fluid (e.g., oil or lubricant) may enter from a source and into the housing assembly <NUM>, and a discharge or outlet port <NUM> through which pressurized fluid may exit for delivery to a system. In operation, the gerotor gears <NUM> create suction at an input port <NUM> causing a fluid to enter the housing assembly <NUM>, and the gerotor gears compress or pressurize the fluid as they rotate, and discharge or output the pressurized fluid through the discharge or outlet port <NUM>. The pump outlet port <NUM> is used for discharging or delivering the pressurized fluid or lubricant to a system such as a transmission or engine, for example.

In an embodiment, the gerotor pump <NUM> may be electrically driven or mechanically driven. For example, the gerotor pump may include a set of electric coils configured to rotate one of the gerotor gears (e.g., the outer gear <NUM>, in accordance with the invention). The electrical power supply may be provided through electrical wires passed through a spout <NUM> of the top cover <NUM>. Hereinafter, the discussion includes electrical drive to illustrate the concepts and working of the gerotor pump <NUM> and does not limit the scope of the present disclosure. The gerotor pump <NUM> may be modified to include mechanical drive as can be understood by a person skilled in the art. For example, in case of mechanically driven gerotor, an input shaft (not shown) may be coupled to one of the gerotor gear (e.g., the inner gear <NUM>, in accordance with the invention) through the bottom casing <NUM> of the housing to drive the gerotor pump <NUM>.

<FIG> is an exploded view of the gerotor pump <NUM> illustrating a controller having an electric circuit board <NUM> that may be part of the electrically driven gerotor pump <NUM>. The electric circuit board <NUM> may receive power or other communication/control signals through the electric wires passed through the spout <NUM>. The electric circuit board may include several electrical components such as resistors, capacitors (e.g., <NUM>, <NUM>, <NUM>), power circuit <NUM>, and/or other electrical components configured to control, for example, current and voltage, to operate the gerotor pump <NUM>. In an embodiment, the electrical circuit board <NUM> may be configured to control current or voltage through electric coils (discussed below) that create magnetic field which may be used to drive a gear (e.g. the outer gear <NUM>) of the gerotor. The electric circuit board <NUM> may be referred to herein as printed circuit board (PCB), or a controller, as may be understood by a person skilled in the art. The PCB <NUM> or controller may be provided in the form of a bus bar, in accordance with an embodiment.

<FIG> and <FIG> are different exploded views of the gerotor pump <NUM> illustrating components of the gerotor pump in a first orientation and a second orientation, respectively. The gerotor pump <NUM> includes the top cover <NUM>, the PCB <NUM>, an intermediate cover or separator <NUM>, the set of gerotor gears <NUM> (including an inner gear <NUM> and an outer gear <NUM>), a spindle <NUM>, a bearing <NUM>, a pin <NUM>, a motor stator <NUM>, and the bottom casing <NUM>. Alternatively or in addition, a pressure plate <NUM> included, for example, in the bottom casing <NUM> of the housing <NUM> to compensate for axial tolerances of the gerotor pump unit. The components of the gerotor pump <NUM> may be coupled together to form a compact assembly within the housing.

In an embodiment, the intermediate separator <NUM> may support the PCB/controller <NUM> on a first side (i.e., between the top cover <NUM> and a top side of the separator <NUM>; see, e.g., <FIG>) and may cover and enclose the gerotor gears <NUM> (<NUM> and <NUM>) and the motor stator <NUM> under the second side (i.e., between the bottom casing <NUM> and a bottom side of the separator <NUM>; e.g., such as shown in <FIG>). In an embodiment, the separator <NUM> may be configured such that the first side does not include any fluid and the second side includes fluid, and thus the separator <NUM> serves as a wall preventing fluid to flow from the second side to the first side. That is, the side with the PCB/controller <NUM> is dry and devoid of fluid, and the side with the pump elements contains fluid. Hence, the separator <NUM> may have a dual functionality of supporting the components on either side, and also serving as a fluid obstruction or a partition.

On the first side (e.g., top side) of the separator <NUM>, the PCB <NUM> may be supported or coupled to the separator <NUM> in a removable manner, according to an embodiment. Referring to <FIG> and <FIG>, the separator <NUM> includes an annular pocket <NUM>, a flange <NUM>, and a bearing support <NUM> on its first side. The bearing support <NUM> may be a hollow shaft-like portion located at a center of the separator <NUM>. When viewed from a top side of the separator <NUM>, the shaft-like portion projects upwards towards the first side (i.e., towards the top cover <NUM>) along the axial direction, and when viewed from a bottom side of the separator <NUM> (see <FIG> and <FIG>), the hollow portion may be formed and accessible from a bottom side. The hollow portion of the bearing support <NUM> may be configured to support or receive a bearing <NUM> (further discussed below with respect to the second side of the separator <NUM>).

Around the shaft-like portion, the annular pocket <NUM> may be formed to accommodate the PCB <NUM> and its components (e.g., the electrical components <NUM>, <NUM>, <NUM>, <NUM>, etc.), thus forming a compact sub-assembly on the first side of the separator <NUM>. Furthermore, upon assembly of the gerotor pump <NUM> and during its operation, the separator <NUM> prevents the PCB <NUM> from contacting the fluid on its opposite side where the pump elements are located. Preferably, electrical components include capacitors, resistors, and other heat generating elements that are in direct contact with the separator <NUM>, and the separator <NUM> is made of thermally conductive material. This enables the heat to be transferred to the fluid on the other side via conduction (i.e., it is transferred through the wall of the separator <NUM>), thus effectively cooling the controller <NUM> and its components.

The flange <NUM> may be formed around the perimeter of the intermediate separator <NUM> and may be used to connect to the top cover <NUM> on one side and the bottom casing <NUM> on the second side. The shape of the flange <NUM> may correspond to a shape, for example, at the perimeter, of the top cover <NUM> and the bottom casing <NUM> to form a seamless assembly of the gerotor pump <NUM>. In the exemplary illustrated embodiment, with the exception of protrusions that are provided in each of the top cover <NUM>, separator <NUM>, and bottom casing <NUM>, the edges of the top cover <NUM>, separator <NUM>, and bottom casing <NUM> may be substantially rounded and/or substantially circular (between the protrusions). While this configuration is not intended to be limiting, it should be understood that the shapes of the perimeters / outer surfaces of the flange <NUM> / separator <NUM>, top cover <NUM>, and bottom casing <NUM> may correspond to each other, such that these parts may be aligned and joined to form the housing <NUM>. Furthermore, in an embodiment, the protrusions are provided in each of the top cover <NUM>, separator <NUM>, and bottom casing <NUM> such that these parts may be aligned for securement together. In one embodiment, the protrusions provided in each of these parts include receiving openings that are designed to be aligned (see, e.g., <FIG> and <FIG>) with each other such that the top cover <NUM>, separator <NUM>, and bottom casing <NUM> may be stacked together and the aligned receiving openings may receive fasteners (e.g., bolts) (not shown) therein, in order to secure these housing parts of the pump together to form the housing assembly <NUM>.

On the second side (e.g., bottom side) of the separator <NUM> may be the hollow shaft-like portion which may be provided to accommodate the bearing <NUM>, such as shown in <FIG>. In an embodiment, the bearing <NUM> may be a ball bearing, a journal bearing or other type of bearing(s). According to the bearing type, the hollow portion of the bearing support <NUM> may be configured to axially fit the bearing <NUM>. The bearing <NUM> may be positioned between the spindle <NUM> and the separator <NUM> (or, more specifically, between the spindle <NUM> and the hollow shaft-like portion of the separator <NUM>). Furthermore, a spindle shaft <NUM> of the spindle <NUM> axially passes into the bearing <NUM>, and, in one embodiment, the spindle shaft <NUM> may further extend beyond the bearing <NUM> to touch or contact the bearing support <NUM>. As such, during operation, the spindle <NUM> may rotate relative to the bearing <NUM> and the intermediate separator <NUM>, while the separator <NUM> is stationary. Also, such arrangement of the spindle <NUM> within the bearing <NUM> enables the spindle <NUM> to be mounted rotatably / for rotation within the housing without the need for extra radial clearance in that region. Typically, in prior art solutions, there is need for, or there tends to be, extra radial clearance for movement of these parts, and this contributes to either a reduced ability to maintain a tight motor air gap between the fixed stator coils of stator <NUM> and rotor coils <NUM> provided on the gerotor outer gear <NUM> (described below), or misalignment during the operation or at the assembly of the gerotor pump <NUM>, or both. This disclosed design, however, does not need or leave any extra radial clearance in the spindle <NUM> / bearing <NUM> region. Instead, a radial position of the magnetic rotor may be fixed (i.e., with a tight motor air gap, or a radial gap <NUM>), or substantially fixed, thereby substantially eliminating or eliminating any influence of the eccentricity of the motor performance. Thus, via the spindle <NUM>, a radial gap <NUM> (see <FIG>) between the rotor coils <NUM>, gerotor gears <NUM>, and the motor stator <NUM> may be maintained with tight tolerance during operation of the pump. This provides, among other things, stable magnetic flux gap and improves noise and vibration performance of the gerotor pump <NUM>. In addition, such configuration of the intermediate separator <NUM> provides for a compact assembly of the gerotor pump <NUM>. For example, upon assembly of the components of the gerotor pump <NUM> on the second side of the intermediate separator <NUM>, a chamber <NUM> (see <FIG>) may be formed between the intermediate separator <NUM> and the bottom casing <NUM>. The chamber <NUM> may be configured to accommodate the gerotor gears <NUM> and the motor stator <NUM> to form a compact assembly.

The spindle <NUM> may be any component configured to hold the set of gerotor gears <NUM> such that the radial movement of the gerotor gears <NUM> may be controlled or maintained with respect to the motor stator <NUM>. In an embodiment, the spindle <NUM> may be a unitary construction of the spindle shaft <NUM>, a flange portion <NUM>, a top surface <NUM> (see <FIG>), and a through hole <NUM> (see <FIG>) in the top surface <NUM>. In an embodiment, the spindle <NUM> may be substantially circular or rounded with the spindle shaft <NUM> at the center of top surface <NUM> and axially projecting upwards or towards a first side (i.e., where the top cover <NUM> is located) from the top surface <NUM>. The flange portion <NUM> may be formed at the perimeter of the top surface <NUM> and projecting downwards or towards a second side (i.e., where the bottom casing <NUM> is located). The flange portion <NUM> may be configured to grip a portion of an outer surface <NUM> of the outer gear <NUM> of the gerotor gears <NUM>. Furthermore, the spindle <NUM> may be fixedly coupled to the outer gear <NUM> via the pin <NUM> passed through the holes <NUM> and <NUM> (when spindle <NUM> and set of gears are stacked together; e.g., see <FIG>). The holes <NUM> and <NUM> are axially aligned with each other to allow the pin <NUM> to pass through the holes, as shown in <FIG>, thus preventing a relative rotation between the spindle <NUM> and the outer gear <NUM> of the gerotor gears <NUM>. In an embodiment, the holes <NUM> and <NUM> may be offset or formed away from an axis of rotation (axis 405a) of the spindle <NUM>; e.g., the holes <NUM> and <NUM> may be formed between the perimeters of the flange portion <NUM> and the outer gear <NUM> (e.g., outer surface <NUM>) and the spindle shaft <NUM>. For example, the hole <NUM> may be formed approximately midway between the spindle shaft <NUM> and the flange <NUM>. Similarly, hole <NUM> may be formed at a corresponding distance to hole <NUM> in through the body of the outer gear <NUM>. In an embodiment, the hole <NUM> may be located offset from the axis of rotation 405a and between the outer surface <NUM> and internal teeth of the outer gear <NUM>. The present disclosure is not limited by a dimension, number of holes, or location of the hole <NUM> (and corresponding hole <NUM> of the outer gear <NUM>). In an embodiment, the diameter of the holes <NUM> and <NUM> may be less than or substantially equal to the pin <NUM> to limit (or prevent) an interplay between the pin <NUM> and the holes <NUM> and <NUM>.

Thus, the spindle <NUM> may be fixed (e.g., via pin <NUM>) to the outer gear <NUM> and configured to rotate together about a first axis 405a within the bearing <NUM>. According to an embodiment, the spindle <NUM> and the outer gear <NUM> (as-is conventionally known of gerotors) may rotate about axis 405a, while the inner gear <NUM> may rotate about a second axis 401a. The first axis 405a and the second axis 401a are offset from each other, allowing the internal gear <NUM> to rotate in an eccentric manner relative to the outer gear <NUM>.

In an embodiment, as mentioned, the set of gerotor gears <NUM> includes the inner gear <NUM> and the outer gear <NUM>. The inner gear <NUM> meshes with the outer gear <NUM> (also illustrated in <FIG>, <FIG>, <FIG>, <FIG>, <FIG> and <FIG>). In an embodiment, the inner gear <NUM> may be coupled within an internal hollow portion of the outer gear <NUM> in an offset manner. In accordance with the invention, the inner gear <NUM> is mounted on a shaft <NUM> (i.e., a drive shaft, such as shown in <FIG>), which may be extending through the bottom casing <NUM>, that rotates about axis 401a, which is offset from the axis of rotation 405a of the spindle <NUM> (and the outer gear <NUM>). The offset arrangement of the gears <NUM> and <NUM> creates a varying volume space between the inner gear <NUM> and the outer gear <NUM> that enable the pumping of fluid. In an embodiment, the inner gear <NUM> may rotate about the axis of the shaft <NUM> (i.e., the second axis 401a) and the outer gear <NUM> may rotate about the spindle <NUM> (i.e., a first axis 405a). In an embodiment, the shaft <NUM> may be an input shaft that may be mechanically driven which may cause rotation of the inner gear <NUM> (i.e., the shaft <NUM> drives the inner gear <NUM>), which further drives the outer gear <NUM>, creating a pumping effect. The drive shaft <NUM> may be configured to be driven by a driver (not shown) such that it rotates about its axis (401a) to drive the gerotor pump <NUM>. Such a driver may include a drive pulley, drive shaft, engine crank, gear, or electric motor, for example. One or more support bearings may support the drive shaft.

The inner gear <NUM> has external teeth (i.e., formed on an outer side of the inner gear <NUM>, as shown in <FIG>, for example) which meshes with internal teeth (i.e., formed on an inner side of the outer gear <NUM>, as shown in <FIG>) of the outer gear <NUM>. As the inner gear <NUM> rotates / meshes with outer gear <NUM>, crescent-like shape(s) may be formed between the teeth of the gears <NUM> and <NUM>. Within these shapes, the (input) fluid is compressed or pressurized as the gears rotate. Furthermore, in one embodiment, the outer gear <NUM> may have greater number of teeth than the inner gear <NUM>, thus the inner gear <NUM> may rotate at a slower speed compared to the outer gear <NUM>. For example, the outer gear <NUM> may have six (<NUM>) internal teeth and the inner gear <NUM> may have five (<NUM>) external teeth. In an embodiment, the gerotor pump <NUM> may be a crescent internal pump, for example, having involute gear and in which the number of teeth on the inner gear differs from the outer gear by more than one. In an embodiment, the gerotor pump <NUM> may not include crescent-like shape(s) between the inner gear <NUM> and the outer gear <NUM> during rotation. The shapes or areas formed between the gears, that receive and pressurize the fluid during rotation, are not intended to be limiting. The type, number, and shape of teeth of the inner gear <NUM>, outer gear <NUM>, the gears themselves, and parts used therewith, are also not intended to be limited.

<FIG> and <FIG> also show the (optional) pressure plate <NUM>, which may be provided in the bottom casing <NUM> (see also, e.g., <FIG>). The inner gear <NUM> may be placed against the pressure plate <NUM> to compensate for any clearance between the inner gear <NUM> and the ports. In accordance with an embodiment, the drive shaft <NUM> may extend through the pressure plate <NUM> and into the housing assembly <NUM>. Furthermore, the pressure plate <NUM> may include two radial slots partially extending in a radial direction and separated from each other. In an embodiment, one radial slot may provide a fluid path from the entry port <NUM> to the gerotor gears <NUM> and a second radial slot may provide a fluid path from the gerotor gears <NUM> to the discharge port <NUM>.

In accordance with the invention, the set of gerotor gears <NUM> may be electromagnetically driven via the outer gear <NUM>. The outer gear <NUM> may include a series of magnets that may be magnetically coupled to the motor stator <NUM> thus forming an electromagnetic motor configuration. In such configuration, the rotor <NUM> may be referred as a motor rotor and the motor stator <NUM> may be referred to as a stator, or vice-versa depending on a relative rotation of the gears <NUM> and the motor stator <NUM>. The rotor <NUM> may be disposed on an outer surface of the outer gear <NUM>, as shown. In an embodiment, a rotor (i.e., the outer gear <NUM>) may be four-pole-rotor, a six-pole-rotor, an eight-pole-rotor, etc. which corresponds to similar number of poles on the stator (i.e., the motor stator <NUM>). For example, the rotor coils <NUM> may be configured to form at least two magnetic poles (a north pole and a south pole), where a first pole may be diametrically opposite to the second pole. In an embodiment, the rotor <NUM> may be permanent magnets having poles corresponding to the motor stator <NUM>. In an embodiment, the motor configuration may correspond to any other type of motors such as a reluctance motor. For example, a reluctance motor configuration where non-permanent magnetic poles on the ferromagnetic rotor may be formed on the outer gear <NUM>.

In an embodiment, the outer gear <NUM> may be disposed internal to the motor stator <NUM> with the radial gap <NUM> (illustrated in <FIG> and <FIG>) in a radial direction, therebetween. In <FIG> and <FIG>, the radial gap <NUM> may be formed between magnets and the poles of the motor stator <NUM>. The radial gap <NUM> is desired to be small (e.g., less than approximately <NUM>) and must be maintained or substantially maintained such that its size/dimension is approximately and relatively consistent during operation of the pump, in order to maintain a relatively high amount of magnetic flux between the motor stator <NUM> and the outer gear <NUM>, with minimal variation, for smooth and efficient operation of the gerotor pump <NUM>. For example, a tolerance or variance of ± <NUM>% of a selected gap or a desired gap (<NUM>) may be maintained in the disclosed pump. If the gap <NUM> increases, the magnetic flux may drop exponentially, thus reducing the efficiency of the gerotor pump <NUM>. According to an embodiment, such radial gap <NUM> may be tightly maintained or controlled due to the coupling between the outer gear <NUM> and the spindle <NUM>. For example, as discussed earlier and as shown in <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, <FIG>, and <FIG>) the outer gear <NUM> may be fixedly coupled to the spindle <NUM> via the pin <NUM>, in accordance with an embodiment. More than one pin may be used in an alternate embodiment.

The motor stator <NUM> is mounted in the casing <NUM> and designed for rotation relative to the gerotor gears <NUM>. The motor stator <NUM> may be coupled to PCB <NUM>, which may be configured to activate the motor stator <NUM> causing the outer gear <NUM> to rotate. In an embodiment, the motor stator <NUM> may be manufactured as an overmolded stator that is supported or mounted in the casing <NUM>, a stator having a core with winding placed in the casing <NUM>, or another type of stator placed therein. An overmolded motor stator <NUM> may include a lamination stack held together via an overmolded resin, for example. The overmolded motor stator <NUM> may also help reduce vibrations during the operation of the gerotor.

According to an embodiment, in operation, the motor stator <NUM> when activated causes the outer gear <NUM> (and the spindle <NUM>) to rotate about the axis 405a. The rotation of the outer gear <NUM> further rotates the inner gear <NUM> about the axis 401a in an eccentric manner. Further, the crescent-like shape(s) between the gears <NUM> and <NUM> causes a suction when the gear teeth disengage, for example, at the suction end <NUM> of the housing, and a compression when the gear teeth engage at a discharge end <NUM> of the housing.

In an embodiment, one or more components of the gerotor may be manufactured from powdered material to limit frictional losses during the operation of the gerotor, thus increasing the efficiency of the gerotor.

The gerotor pump <NUM> according to the present disclosure has several non-limiting advantages, some of which have been noted previously. For example, a gap (e.g., radial gap <NUM>) may be maintained approximately consistent during assembly and operation of the gerotor pump, thus providing a relatively consistent flux throughout the radial gap <NUM> thereby increasing operational efficiency and operating speed. According to an embodiment, by using the spindle <NUM> and the bearing <NUM> without extra radial clearances (and/or by limiting their radial clearance and/or movement, while still effectively maintaining the gap <NUM>), the less-sensitive issue of radial clearance between the gear teeth tips can be managed by tolerances between the inner gear bore and the shaft <NUM> received in it. Furthermore, the spindle <NUM> and bearing <NUM> arrangement may reduce vibrations, for example, between the outer gear <NUM> and the inner gear <NUM>, thereby maintaining a tight gap between the motor stator <NUM> and the electric coils of the outer gear <NUM>. Also, reduced vibration enables maintaining a consistent gap <NUM>, allowing the gerotor gears <NUM> to be rotated at increased speed. The spindle <NUM> enables self-alignment during assembly and when the gerotor is operating. The spindle <NUM> (with the bearing <NUM>) and the pin <NUM> connection with the gear set reduces the requirement of a high precise gear tip tolerances (e.g., between the engaging gear teeth) between the inner gear <NUM> and the outer gear <NUM>.

Furthermore, the complexity of field orientation control (FOC) may be reduced (e.g., due to reduced vibration), thus allowing driving the pump at high speeds.

Using the pressure plate <NUM> in combination with the spindle <NUM> also allows for compensation with regards to tolerances of the pump unit, and overcome issues with regards to integration. The frictional impact between rotating parts is dramatically reduced with the used of, for example, bearing <NUM> compared to use of bushings.

Active cooling of the controller may be implemented via the construction of the separator <NUM> and fluid in the housing assembly, thereby enabling better thermal measurement and control for the controller (e.g., PCB <NUM>). Also, use of a PCB bus bar to replaces a conventional bus bar, in accordance with an embodiment, may further reduce the cost associated with the pump.

An overmolded motor stator <NUM> may be used to overcome seal issues. In accordance with an embodiment, the stator may be formed using a powder metal. Furthermore, in an embodiment, an overmolded rotor may be formed, e.g., by a powder metal. In an embodiment, both the stator and rotor may be overmolded. In one embodiment, a sheet mounting compound (or composite) process (SMC) may be utilized, e.g., to manufacture the outer gear <NUM> with the rotor coil <NUM>, thereby reducing the cost of manufacturing, as well as to eliminate laminations from the stator.

Furthermore, the gerotor pump <NUM> has improved overall motor (or pump) efficiency based on consistent air gap and corresponding magnetic flux, and improved pump's mechanical efficiency based on reduced friction between rotating parts. In accordance with an embodiment, up to fifty (<NUM>) percent (%) of existing friction between parts may be eliminated in the disclosed design as compared to prior art solutions. Furthermore, motor integration may be established, in accordance with an embodiment, by using sheet molding compound (SMC) material for outer rotor (e.g., rotor coils <NUM>) and magnets, in accordance with an embodiment. The electric oil pump assembly process may be more robust. An intermediate ring may be used to improve hydrodynamic lubrication between the spindle and bearing.

As previously noted, the gerotor pump <NUM> may be associated with a system in accordance with an embodiment of the present disclosure. The system may be a vehicle or part of a vehicle, for example. Such a system may include a mechanical system such as an engine (e.g., internal combustion engine) and/or a transmission of an automotive vehicle for receiving pressurized lubricant from the pump <NUM>. The pump <NUM> receives (input via pump inlet) fluid / lubricant (e.g., oil) from a lubricant source and pressurizes and delivers it to the engine or transmission (output via outlet). A sump or tank may be the lubricant source that inlets to the pump <NUM>. The controller in the pump <NUM> may be designed for implementing actuation of the system and/or pump <NUM>.

While the principles of the disclosure have been made clear in the illustrative embodiments set forth above, it will be apparent to those skilled in the art that various modifications may be made to the structure, arrangement, proportion, elements, materials, and components used in the practice of the disclosure.

Claim 1:
A gerotor pump (<NUM>) comprising:
an inlet (<NUM>) for receiving fluid from a source;
an outlet (<NUM>) for delivering pressurized fluid to a mechanical system therefrom;
an outer gear (<NUM>) mounted relative to a first axis (405a);
an inner gear (<NUM>) mounted on a second axis (401a) for rotation, the outer gear meshing internally with the inner gear in an offset manner;
a drive shaft (<NUM>) coupled to the inner gear, the drive shaft being configured to be driven by a driver, to mechanically drive the inner gear about the second axis in order to pressurize the received fluid for output as the pressurized fluid;
an electrical motor including a rotor (<NUM>) and a stator (<NUM>) having a radial gap (<NUM>) therebetween in a radial direction, the rotor being disposed on an outer surface of the outer gear, and the electrical motor configured to electromagnetically drive the outer gear to rotate and thus further rotate the inner gear about the second axis in an eccentric manner, characterized by:
a spindle (<NUM>) fixedly coupled to the outer gear to facilitate substantially maintaining the radial gap between the rotor and the stator in the radial direction, and configured for rotation about the first axis;
a bearing support (<NUM>); and
a bearing (<NUM>) accommodated by the bearing support (<NUM>),
the spindle (<NUM>) having a spindle shaft (<NUM>) axially received in the bearing (<NUM>) to rotationally mount the spindle (<NUM>) and fix or substantially fix a radial position of the rotor (<NUM>) to substantially maintain the radial gap (<NUM>).