Electro-hydraulic actuators and related systems and methods

Abstract

Systems and methods related to electrically driven hydraulic pumps and electro- hydraulic actuators are disclosed. In some embodiments, an electrically driven hydraulic pump may include an electrical unit with a support plate that is configured to form an interior surface of a sealed hydraulic volume of a hydraulic module and / or radially support a bearing of a rotor shaft configured to radially support a driveshaft of the hydraulic module. In other embodiments, an electrical unit may include a rotor disposed at least partially within a sealing cup and a potting compound may be disposed within a gap between the sealing cup and one or more portions of a stator housing and / or stator. In yet another embodiment, an electro- hydraulic actuator may include a snap ring compressed between first and second grooves formed in a first portion of a housing and an electrically driven hydraulic pump to prevent separation of the electro-hydraulic actuator.

Description

L0710.70106WQ00- 1 - ELECTRO-HYDRAULIC ACTUATORS AND RELATED SYSTEMS AND METHODSCROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119(e) of U.S. provisional application serial number 63 / 738,097 filed December 23, 2024, the disclosure of which is incorporated by reference in its entirety.FIELD

[0002] Disclosed embodiments are related to electro-hydraulic actuators and related systems and methods.BACKGROUND

[0003] Electro-hydraulic actuators are electrically driven self-contained hydraulic systems that may be commanded to apply forces in various applications such as automotive (e.g. active suspension systems), aeronautics (e.g. control surface actuation), and robotics. The primary subsystems of an electro-hydraulic actuator are typically a hydraulically driven piston assembly (that includes a piston attached to a piston rod and slidably received in an internal volume of a cylindrical housing) and an electrically driven hydraulic pump. In such systems, typically the electrically driven hydraulic pump is either attached directly to the hydraulically driven piston assembly or to an intervening manifold. Typically multiple fasteners are distributed around the periphery of the connection point and are made of highgrade materials and are of a suitable size to withstand the large separating forces between the electrically driven hydraulic pump and the hydraulically driven piston assembly.SUMMARY

[0004] In some embodiments, an electrical unit comprises: a rotor shaft with a first rotor shaft end portion and a second rotor shaft end portion; a bearing configured to radially support the rotor shaft at the second rotor shaft end portion; and a support plate with a first surface and a second surface opposite the first surface, wherein the support plate is configured to radially support the bearing, wherein the first surface of the support plate is configured to form an interior surface of a volume of a hydraulic module that is exposed to hydraulic fluid during operation when the hydraulic module is attached to the electrical unit,#14746377vlL0710.70106WQ00- 2 -and wherein the electrical unit is configured to operate as an electrical motor in a first mode of operation.

[0005] In some embodiments, an electrically driven hydraulic pump comprises: an electrical unit configured to be operated as an electrical motor in a first mode of operation, the electrical unit comprising: a rotor shaft having a first rotor shaft end portion and a second rotor shaft end portion; a first bearing configured to radially support the first end portion of the rotor shaft; a second bearing configured to radially support the second end portion of the rotor shaft; and a support plate configured to support the second bearing. The electrically driven hydraulic pump further comprises a hydraulic module that is configured to be operated as a pump in the first mode of operation, the hydraulic module comprising: a driveshaft including a first driveshaft end portion and a second driveshaft end portion; and a third bearing configured to radially support the second driveshaft end portion, wherein the first driveshaft end portion is operatively torsionally coupled to the second rotor shaft end portion and wherein the first driveshaft end portion is radially supported by the second end portion of the rotor shaft.

[0006] In some embodiments, a method of operating an electrically driven hydraulic pump comprises: supporting a rotor shaft of an electrical unit with a bearing; supporting the bearing with a support plate; and driving a driveshaft of a hydraulic module with the rotor shaft in a first mode of operation, wherein the support plate forms an interior surface of a hydraulically sealed volume of the hydraulic module that is exposed to hydraulic fluid during operation of the electrically driven hydraulic pump.

[0007] In some embodiments, a method of operating an electrically driven hydraulic pump comprises: radially supporting a first rotor shaft end portion of a rotor shaft of an electrical unit, with a first bearing; radially supporting a second end portion of the rotor shaft with a second bearing; radially supporting and torsionally coupling a first end portion of a driveshaft of a hydraulic module with the second end portion of the rotor shaft; and in a first mode of operation torsionally driving the driveshaft of the hydraulic module with the rotor shaft.

[0008] In some embodiments, an electrical unit comprises: a stator housing; a stator disposed in the stator housing; a sealing cup closed at a distal end portion and open at a proximal end portion, wherein the sealing cup is disposed within the stator housing in a cylindrical cavity extending axially through the stator such that a gap is formed between a#14746377vlL0710.70106WQ00- 3 -portion of the stator housing and the distal end portion of the sealing cup and an interior surface of the cylindrical cavity of the stator and the sealing cup; a potting compound disposed in the gap between the portion of the stator housing and the distal end portion of the sealing cup and the interior surface of the cylindrical cavity of the stator and the sealing cup; and a rotor disposed at least partially within an interior volume of the sealing cup.

[0009] In some embodiments, a method for manufacturing an electrical unit comprises: positioning a sealing cup into a cylindrical cavity extending axially through a stator to form a gap between a closed distal end potion of the sealing cup and a stator housing of the stator and between the sealing cup and the internal surface of the cylindrical cavity; and filling the gap with a potting compound.

[0010] In some embodiments, an electro-hydraulic actuator comprises: an electrically driven hydraulic pump; a housing; a first at least partially continuous annular groove associated with the electrically driven hydraulic pump; a second at least partially continuous annular groove associated with a first portion of the housing, wherein a first opening of the first groove is oriented towards and is located in at least a partially overlapping axial position with a second opening of the second groove when the electrically driven hydraulic pump is fully inserted in the housing; and a snap ring disposed between and at least partially received in the first and second openings of the first at least partially continuous annular groove and the second at least partially continuous annular groove, wherein when assembled in the electro-hydraulic actuator, the snap ring prevents relative movement between the housing and the electrically driven hydraulic pump along an of axis insertion of the electrically driven hydraulic pump into the housing.

[0011] In some embodiments, a method for assembling an electro-hydraulic actuator comprises: moving one or both of a first portion of a housing and an electrically driven hydraulic pump along an axis of insertion to assemble the first portion of the housing and the electrically driven hydraulic pump; camming a snap ring into one of a first at least partially continuous annular groove associated with the electrically driven hydraulic pump and a second at least partially continuous annular groove associated with the first portion of the housing during assembly of the first housing portion and the electrically driven hydraulic pump; and moving the first housing portion, the electrically driven hydraulic pump, and the snap ring to a locked configuration, wherein the snap ring is disposed between and captured within axially overlapping portions of the first at least partially continuous annular groove#14746377vlL0710.70106WQ00- 4 -and the second at least partially continuous annular groove to prevent relative movement of the housing and the electrically driven hydraulic pump along the axis of insertion.

[0012] In some embodiments, an electrically driven hydraulic pump comprises: an electrical unit that includes: a controller housing that includes: one or more circuit boards, at least one processor, and a position sensor; the electrical unit further includes a stator housing that includes: a stator rigidly held within the stator housing with at least one pin connection protruding from the stator housing, a rotor shaft having a first rotor shaft end portion and a second rotor shaft end portion, wherein a target magnet with a north-south axis is positioned substantially perpendicular to an axis of rotation of the rotor shaft and located at the first rotor shaft end, a first bearing configured to radially support the first rotor shaft end portion, a second bearing configured to radially support the second rotor shaft end portion, and a support plate configured to support the second bearing; the electrical unit further includes at least one tab and at least one corresponding groove; wherein the at least one tab is configured and positioned to engage the at least one groove and: secure the stator housing axially and rotationally relative to the controller housing when the stator housing is inserted into the controller housing during assembly, place the at least one pin connection in contact with a receiving electrical contact on the at least one circuit board, and align the target magnet with the position sensor.

[0013] It should be appreciated that the foregoing concepts, and additional concepts discussed below, may be arranged in any suitable combination, as the present disclosure is not limited in this respect. Further, other advantages and novel features of the present disclosure will become apparent from the following detailed description of various nonlimiting embodiments when considered in conjunction with the accompanying figures.BRIEF DESCRIPTION OF DRAWINGS

[0014] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

[0015] Fig. 1 shows a schematic view of an electro-hydraulic actuator according to some embodiments;#14746377vlL0710.70106WQ00- 5 -

[0016] Fig. 2 shows an isometric view of an electrical unit subassembly according to some embodiments;

[0017] Fig. 3 shows a close-up isometric view of a portion of an electrical unit subassembly according to some embodiments;

[0018] Fig. 4 shows a close-up cross-sectional view of a portion of an electrical unit subassembly according to some embodiments;

[0019] Fig. 5 shows another close-up cross-sectional view of a portion of an electrical unit subassembly according to some embodiments;

[0020] Fig. 6 shows an exploded isometric view of an electrical unit subassembly according to some embodiments;

[0021] Fig. 7 shows another close-up cross-sectional view of an electrical unit subassembly according to some embodiments;

[0022] Fig. 8 shows a cross-sectional view of an electrical unit subassembly according to some embodiments;

[0023] Fig. 9 shows an isometric view of a first portion of a coupling according to some embodiments;

[0024] Fig. 10 shows an isometric view of a second portion of a coupling according to some embodiments;

[0025] Fig. 11 shows a cross-sectional view of an electrical unit subassembly including a sealing cup according to some embodiments;

[0026] Fig. 12 shows an exploded isometric view of an electrical unit subassembly including a sealing cup according to some embodiments;

[0027] Figs. 13A-13B shows a cross-sectional view of an electrical unit subassembly during an overmolding process according to some embodiments;

[0028] Fig. 14 shows a close-up cross-sectional view of an electrical unit subassembly in with a potting compound present between the sealing cup and other portions of the subassembly according to some embodiments;

[0029] Fig. 15 shows a perspective view of an electrically driven hydraulic pump including an electrical unit, a hydraulic module, and a differential buffer according to some embodiments;#14746377vlL0710.70106WQ00- 6 -

[0030] Fig. 16 shows an exploded perspective view of an electrically driven hydraulic pump including of an electrical unit, a hydraulic module, and a differential buffer according to some embodiments;

[0031] Fig. 17 shows a close-up perspective view of an electrical unit subassembly including a tab according to some embodiments;

[0032] Fig. 18 shows a perspective view of an electrically driven hydraulic pump being assembled with a manifold according to some embodiments;

[0033] Fig. 19 shows yet another perspective view of an electrically driven hydraulic pump being assembled with a manifold according to some embodiments;

[0034] Fig. 20 shows a perspective view of an electrically driven hydraulic pump including with a manifold coupled thereto according to some embodiments;

[0035] Fig. 21 shows a cross-sectional view of an electrically driven hydraulic pump with a manifold coupled thereto according to some embodiments;

[0036] Fig. 22 shows a cross-sectional isometric view of a second portion of a coupling attached to a driveshaft of a hydraulic module according to some embodiments;

[0037] Fig. 23 shows a cross-sectional isometric view of a coupling between a rotor shaft and a driveshaft of a hydraulic module according to some embodiments;

[0038] Fig. 24 shows an exploded cross-sectional isometric view of a coupling between a rotor shaft and a driveshaft of a hydraulic module according to some embodiments;

[0039] Fig. 25 shows a cross-sectional view of an electrically driven hydraulic pump according to some embodiments;

[0040] Fig. 26A shows a first close-up cross-sectional view of a snap ring in an electrical unit subassembly according to some embodiments;

[0041] Fig. 26B shows a second close-up cross sectional view of a snap ring in an electrical unit subassembly according to some embodiments;

[0042] Fig. 26C shows a third close-up cross-sectional view of a snap ring in an electrical unit subassembly according to some embodiments;

[0043] Fig. 27A shows a fourth close-up cross-sectional view of a snap ring in an electrical unit subassembly according to some embodiments;

[0044] Fig. 27B shows a fifth close-up cross-sectional view of a snap ring in an electrical unit subassembly according to some embodiments;#14746377vlL0710.70106WQ00- 7 -

[0045] Fig. 27C shows a sixth close-up cross-sectional view of a snap ring in an electrical unit subassembly according to some embodiments; and

[0046] Fig. 27D shows a seventh close-up cross-sectional view of a snap ring in an electrical unit subassembly according to some embodiments.DETAILED DESCRIPTION

[0047] Electrically driven hydraulic pumps often include a hydraulic module and an electrical unit both of which include portions of the electrically driven hydraulic pump that may be needed to test the functionality of the other. For example, the hydraulic module may include a hydrostatic pump / motor connected to a driveshaft with a rotor for use with a brushless DC motor (e.g., of a corresponding electrical unit), as well as bearings to support the driveshaft and a driveshaft position sensor magnet. The electrical unit may correspondingly include the stator portion of the brushless DC motor and the motor controller, which also may include the driveshaft position sensor. As such, to test the functionality of the electrical unit, for example, the rotor, the hydraulic module (including the rotor) must be operatively coupled to the electrical unit. Accordingly, the electrical unit in most cases may not be tested separately from the hydraulic module as supports, drive components, and / or other components needed to support and test the functionality of the electrical unit may be missing. Therefore, in order to test an electrical unit it is assembled with a corresponding hydraulic module. This increases the time and cost associated with the assembly process due to the time needed to assemble and disassemble electrical units and hydraulic modules when, for example, a defective electrical unit is discovered after being assembled to perform the desired testing.

[0048] In addition to the above, calibration of the electrically driven hydraulic pump is often desirable for accurate operation of the motor. Calibrating the electrically driven hydraulic pump may include determining the relative positioning of the position sensor magnet to the rotor magnets to enable the controller to accurately commutate windings of the motor, thereby enabling accurate control of the motor. Similar to the above issues regarding typical electrical units of an electrically driven hydraulic pump only being able to be tested after assembly with a hydraulic module, calibration in typical systems is also performed after the hydraulic module and the electrical unit are assembled to form the electrically driven hydraulic pump. This presents the same challenges and inefficiencies when defective#14746377vlL0710.70106WQ00- 8 -electrical units are only discovered after being assembled with a corresponding hydraulic module. Additionally, in some cases, e.g. during endurance testing, when failure or faulty performance is detected in an assembly comprising an electrical unit and the corresponding hydraulic module, it may be difficult, time consuming, or impossible to determine if the electrical unit or the hydraulic module is at fault. Furthermore, when testing an assembly comprising both an electrical unit and a hydraulic module, both hydraulic and electrical equipment may be required in the same test facility. This would add complexity and cost to the testing processes.

[0049] In view of the above, the inventors have recognized that an inability to test an electrical unit separately from the hydraulic module of an electrically driven hydraulic pump reduces the detectability of defects, thereby increasing a risk of assembling a defective system, which may result in increased cost as well as wasted time and materials. Further, in some situations, one or more suppliers may manufacture and assemble components of the hydraulic module which are different than the supplier of the electrical unit, which is often due to the different manufacturing, assembly processes, and expertise associated with these different components. Therefore, a combined rotor and driveshaft assembly is often transported to the hydraulic module supplier which presents challenges due at least in part to the relatively strong magnets included on the rotor and driveshaft assembly. These challenges may include increased time and cost in preventing contamination (e.g., steel contamination) of the assembly as well as excess costs associated with additional shipping of components between different manufacturers. Further, shipping may present logistical challenges such as managing inventory and delivery schedules, which may be especially burdensome in mass production.

[0050] In view of these challenges, the inventors have recognized that it may be desirable for an electrical unit of an electrically driven hydraulic pump to be designed to provide a complete self-contained electrical unit which may enable calibration, testing and / or verification of the electrical unit prior to assembly with a separate hydraulic module of an electrically driven hydraulic pump. However, such an electrical unit may still desirably permit easy assembly with the hydraulic module.

[0051] In some embodiments, the inventors have recognized the benefits associated with implementing an intermediate bearing supported by a support plate of an electrical unit that may be used to radially support a rotor shaft of the electrical unit. In some cases, a#14746377vlL0710.70106WQ00- 9 -separate driveshaft of a hydraulic module may be connected to the rotor shaft by an appropriate coupling that provides both rotational coupling and radial support to the connected portion of the driveshaft of the hydraulic module. Thus, the support plate and associated bearing may be used to support both an end portion of the rotor shaft, and when assembled and coupled thereto, a corresponding end portion of a driveshaft of the hydraulic module. This is in contrast to other electrical unit and hydraulic module designs where a combined rotor shaft and driveshaft are supported by common bearings or separate rotor shafts and driveshafts supported by two separate sets of bearings and bearing supports are used. This latter option may add to the cost, weight, and size of the assembly.

[0052] The inventors have also recognized that it may be desirable for the support plate of the electrical unit to form a functional portion of the hydraulic module. For example, the support plate or a bearing of the electrical unit may be configured to form an interior surface that at least partially defines an internal volume of the hydraulic module that is exposed to hydraulic fluid during normal operation of the electrically driven hydraulic pump. In one exemplary embodiment, the support plate may function as a cap (e.g., an end cap) of a hydraulic module. Since the support plate may be exposed to the internal volume of the hydraulic module, the support plate may also include one or more functional features formed therein such as one or more false ports of a gerotor or other functional portion of the hydraulic module in some embodiments. By forming a portion of the hydraulic module with the support plate, this may beneficially help to limit an overall length of the assembled electrically driven hydraulic pump which may be desirable in size limited applications such as active suspension system actuators located within a wheel well of a vehicle.

[0053] In some cases, an electrical unit may include a brushless DC motor rotor, a stator, a, position sensor magnet, and a position sensor. In some cases, a magnet may be coupled to an end portion of a rotor shaft of the electrical unit such that the magnet is configured to rotate with the rotor shaft during operation of the electrical unit. In some embodiments, and as elaborated on further below, the magnet may be disposed within a sealed volume formed by a sealing cup disposed within the stator housing in a cylindrical cavity extending axially through the stator. In some embodiments, the magnet may be configured such that the position of the magnet is indicative of the position of the rotor. For example, in some cases, the magnet (e.g., target magnet) may be attached to the rotor shaft with a north-south axis that is substantially perpendicular to an axis of rotation of the rotor#14746377vlL0710.70106WQ00- 10 -shaft. A sealing cup may be used in some embodiments where it is desirable to avoid partially or fully submerging the stator of the electrical unity in high pressure hydraulic fluid that the rotor may be exposed to.

[0054] As previously mentioned, a stand-alone electrical unit may permit testing of the electrical unit prior to assembly / testing with the hydraulic module and other components of an electro-hydraulic actuator. After testing, the disclosed electrical units may be assembled with a hydraulic module to function as an electrically driven hydraulic pump of an electro-hydraulic actuator. Such separate manufacturing and potential testing of these systems may increase manufacturing efficiency and improve system quality while also potentially minimizing the quantity, weight, and cost of the components. Reducing the quantity of the components may also offer benefits such as simplified manufacturing, reduced complexity, and reduced size of one or more portions of the electro-hydraulic actuator. This may offer logistical benefits including easier and / or simplified assembly into a system.

[0055] In cases where an electrical unit is formed separately, the electrical unit may include any combination of basic components included in an electrical unit. For example, this may include one or more (e.g., all) of the following components: a motor stator and stator housing; a rotor shaft assembly which may contain the motor rotor and a position sensor magnet; a position sensor; one or more bearings (e.g., a bearing arrangement) to locate and / or support the rotor shaft assembly; and a controller including one or more processors configured to operate the electrical unit. In some embodiments, it may also be desirable for the electrical unit controller housing to not be integrally formed into the stator housing, which may allow the controller assembly (which may include the position sensor) to be manufactured as a separate sub-assembly that may be coupled to the stator housing. Using a separate (e.g., not integrally formed with the stator housing) controller housing may enable the controller housing to be formed with lighter and in some cases less expensive materials, such as polymer (e.g., plastic). Forming the controller housing out of polymer may enable more efficient and, in some cases, less expensive manufacturing and / or assembling processes, such as injection molding. Forming the controller housing out of polymer may also offer the logistical benefit of additional options for suppliers / manufacturers using a separate controller supplier from that of the electrical unit supplier, therefore increasing the potential for time and cost savings, and in some cases increased quality where suppliers specializing in each component / assembly may be sourced. In some embodiments, the pressure sensor of the#14746377vlL0710.70106WQ00- 11 -electrically driven hydraulic pump may be connected with the controller, and as such it may be desirable for the pressure sensor to be integrated into the stator housing of the electrical unit, for example, such that when the controller is assembled, the pressure sensor may be able to communicate with the controller assembly (e.g., a PCB of a controller assembly). In some embodiments, the pressure sensor may also be configured to be in fluid communication with a sensing port formed in the above noted support plate that is in fluid communication with an internal volume of the hydraulic module when assembled therewith.

[0056] As elaborated on in further detail relative to the figures, the various housings may be connected to each other in any appropriate fashion. For example, in some embodiments, the controller assembly (which may include the position sensor) may be a separate sub-assembly that comprises one or more controller housings (e.g., injection molded and / or polymer housings) that may be positioned relative to the stator housing of the electrical unit. In some cases, one or more fasteners may be used to secure the one or more controller housings relative to the stator housing. However, in some instances, it may be desirable to connect the various housings to each other using snap connections formed in the housings without additional separate threaded fasteners. For example, a controller housing may optionally include one or more snap connections for securing the controller housing relative to the stator housing. Similarly, snap connections may be used to connect the stator housing to an external housing of an electrically driven hydraulic pump. However, it should be understood that the various components and housings may be connected to one another in any appropriate manner using any appropriate type of connection as the disclosure is not so limited. Also, it should be noted that although some depicted embodiments herein show a separate controller sub-assembly, the controller housing and the controller sub-assembly may be integrated with the electrical unit motor housing as the disclosure is not limited by the formation of the controller housing.

[0057] The inventors have recognized that it is desirable to avoid leakage of hydraulic fluid from an interior volume containing (e.g., flooded with) hydraulic fluid which the rotor is disposed in to other portions of the electrical unit. Thus, a sealing cup may be positioned between the rotor and a cylindrical cavity extending through a corresponding stator the rotor is disposed within. However, in many cases, regardless of manufacturing processes and tolerances, an air gap may be present between the sealing cup and the cavity the rotor is disposed within. The inventors have recognized that rapid duty cycles, pulsations, and other#14746377vlL0710.70106WQ00- 12 -cyclic loads applied to the system during operation may result in fatigue fracturing of the unsupported sealing cup over time due to the presence of this air gap which may result in corresponding undesirable leakage of hydraulic fluid from the sealed interior volume into one or more other portions of the electrical unit through the fractured sealing cup.

[0058] In view of the above, the inventors have recognized the benefits associated with creating an intentionally sized gap that is sized and shaped to permit a potting compound to be injected into the gap to support the sealing cup. It is noted that the intentional gap does not necessarily need to be uniform in thickness. In one such embodiment, the sealing cup is sized and shaped to form a gap between a distal end portion of the sealing cup and an adjacent portion of a stator housing as well as between the sealing cup and an interior surface of the channel (e.g., a cylindrical cavity) extending through the stator. The gap may be filled with any appropriate potting compound. In some embodiments, at least a portion of the sealing cup may be tapered about an axis of rotation of the rotor shaft. In some cases, the tapered portion of the sealing cup may form a surface of the gap between the stator housing and the sealing cup. To facilitate assembly with a hydraulic unit, and as elaborated on further below, in some embodiments, a hydraulic seal may also be positioned such that the hydraulic seal may be disposed between the sealing cup and an end cap of a hydraulic unit when the hydraulic unit is attached thereto. In either case, the use of such a gap and the potting compound may help to prevent leakage from the interior volume containing the hydraulic fluid during operation. Specifically, the use of such a potting compound in the gap may help to support the sealing cup during cyclic loading which may help to mitigate possible fatigue fracture of the sealing cup. As noted above, any appropriate type of potting compound may be used to fill the gap between a sealing cup and one or more other surrounding portions of the stator.

[0059] The thickness of a gap between a sealing cup and adjacent portion of a stator may be selected to permit a desired potting compound to flow into the gap. This may be based on appropriate design parameters such as injection pressure, injection temperature, viscosity, curing time, and / or any other appropriate design parameter. The thickness may be uniform or variable, and at any appropriate location, e.g. measured between a location on a sealing cup and the closest adjacent portion of the stator. In some embodiments the sealing cup may touch the stator housing at one or more locations.#14746377vlL0710.70106WQ00- 13 -

[0060] In addition to the above, the inventors have recognized that implementing connections between different components and / or housings which reduce or eliminate the use of treaded fasteners and / or connectors (e.g. bolts, screws), which are often used to secure an electrically driven hydraulic pump and a hydraulically driven piston assembly, may offer several benefits. For example, reducing or eliminating the quantity of threaded fasteners may reduce the size and weight of the interface, providing the benefit of simplified and / or less costly assembly and shipping, among other benefits. Reducing or eliminating the threaded fasteners from the interface may also enable forming other portions of the interface with lighter materials, including but not limited to cast or forged aluminum. Further, in cases where the threaded fasteners are formed of steel and other components of the assembly are formed of other materials, differences in the coefficient of thermal expansion within the assembly may be present, which may complicate and / or limit design and manufacturing processes, thereby increasing cost and / or decreasing efficiency. Additionally, the operating temperature range of the actuator may present challenges related to providing a sufficient preload at or around a minimum operating temperature to provide a connection capable of resisting disturbing forces applied to the threaded fasteners, while avoiding over stressing the threaded fastener at a maximum operating temperature. These limitations associated with typical threaded fasteners may therefore complicate and / or limit design and manufacturing processes for electro-hydraulic actuators.

[0061] In addition to the above, threaded fasteners are often coated to avoid corrosion and, in some cases, so the system may not be easily taken apart without special tooling to prevent an untrained end user from mistakenly disassembling the system while the system is pressurized. Coating the fasteners may be costly and further complicate manufacturing processes in some cases. Further, the inventors have recognized that threaded interfaces included in electro -hydraulic actuators often include a separate pressure seal (that seals from both internal and external pressure differentials) and an environmental seal that protects the pressure seal (and any associated sealing surfaces) from a corrosive environment that it may be subjected to. This type of sealing arrangement may increase the cost and complexity of the system and / or negatively impact durability. Additionally, the geometry in existing interfacing structures with threaded fasteners and the various orientations of interfacing structures relative to one another, e.g., in comers of an automotive active suspension system, may result in fasteners that are accessed from different directions, which may present manufacturing and#14746377vlL0710.70106WQ00- 14 -assembly, and or installation challenges, including increased complexity and cost for automated insertion and securing of such the threaded fasteners in mass production.

[0062] Based on the forgoing, the inventors have recognized that threaded fasteners used to hold and maintain the pressurized components of an electro-hydraulic actuator in a desired position relative to one another complicate the design, manufacture, assembly, and / or installation of the system. This may be especially applicable for the pressurized interface between an electrically driven hydraulic pump and a hydraulically driven piston assembly of an electro-hydraulic actuator. Thus, it may be desirable to reduce or eliminate threaded fasteners from an interface between the electrically driven hydraulic pump and a hydraulically driven piston assembly. Further, the inventors have recognized the benefits associated with a simplified mechanical and fluidic connection that may be configured so that the electrically driven hydraulic pump and hydraulically driven piston assembly may be securely attached, via an intervening manifold, to form a structurally robust connection that may simultaneously resist the disturbing forces applied to the system (for example, resulting from separating forces generated by hydraulic pressures, shock and vibration and acceleration forces and exposure to temperature extremes), provide hydraulic fluid flow paths and sealing of the fluidic connections (both from internal pressure cavity sealing and sealing against bidirectional pressure differences from internal to external pressures), provide protection from the corrosive environment, properly locate the electrically driven hydraulic pump relative to the hydraulically driven piston assembly, and / or result in a sufficiently tamper proof connection. In some embodiments, the simplified mechanical and fluidic connection may include one or more of the aforementioned benefits though other benefits may be provided as the current disclosure is not so limited.

[0063] In view of the above, the inventors have recognized the benefits associated with a connection formed using one or more snap rings, that are engaged as a portion of a housing that may be operatively coupled to a hydraulically driven piston assembly is moved into a locked configuration with an electrically driven hydraulic pump. This may form a connection that locks the housing and the electrically driven hydraulic pump in a desired assembled configuration. In some embodiments, the housing portion of the hydraulically driven piston assembly and the hydraulic module may include one or more pairs of corresponding at least partially continuous, or continuous, annular grooves. Each groove may include an opening, and the openings of the grooves may be oriented towards each other and#14746377vlL0710.70106WQ00- 15 -may be located in at least partially overlapping axial positions with each other when the housing and the electrically driven hydraulic pump are in the assembled configuration. A snap ring may be disposed on either the electrically driven hydraulic pump or the housing and may be aligned with the corresponding groove.

[0064] During assembly, one or more camming surfaces formed on the housing and / or the electrically driven hydraulic pump may be configured to displace the snap ring out of a path of movement of the housing and / or electrically driven hydraulic pump. In some embodiments, the grooves, cams, and snap ring may be configured to allow the snap ring to cam out of the path of insertion of the housing and electrically driven hydraulic pump. For example, the snap ring may be cammed into one of the grooves during assembly. The snap ring may be biased towards a locked configuration. Thus, once sufficiently displaced towards an engaged configuration, the snap ring may be biased into a locked configuration that is captured between the two opposing grooves which may prevent relative motion of the housing associated with the hydraulically driven piston assembly and the electrically driven hydraulic pump along an axis of insertion corresponding to a direction in which the electrically driven hydraulic pump and / or housing are displaced during assembly. This may correspondingly prevent relative motion of the electrically driven hydraulic pump and the hydraulically driven piston assembly.

[0065] In some embodiments, the housing may include a manifold that when assembled with the electrically driven hydraulic pump may place the electrically driven hydraulic pump in fluid communication with the hydraulically driven piston assembly. In such an embodiment, the manifold may be considered to be part of the housing. Depending on the embodiment, the manifold may be directly connected to the electrically driven hydraulic pump with the above noted snap ring connection and the remaining portions of the housing may be connected to the manifold using any appropriate type of connection.However, embodiments in which a connection is formed with a different portion of the housing and the manifold is indirectly held in a desired assembled configuration with the electrically driven hydraulic pump to provide an indirect connection with the manifold are also contemplated. Additionally, in some embodiments, a manifold and / or the hydraulically driven piston assembly may be integrated or may be integrally formed with the housing. Thus, it should be understood that the disclosed snap ring connections may be used to provide a connection between any appropriate portions of an associated housing including, in some#14746377vlL0710.70106WQ00- 16 -embodiments, direct and / or indirect connections with a manifold and / or the hydraulically driven piston assembly.

[0066] In addition to the above, in some embodiments, an electrically driven hydraulic pump of an electro-hydraulic actuator may include: a stator housing; an electrical unit at least partially located in a cavity in the stator housing and that includes a stator, an electric motor rotor shaft, with an axis of rotation, that has a first end portion and a second end portion, where the first end portion is radially supported by a first bearing and the second end portion is radially supported by a second bearing; a support plate that supports the second bearing; and a target magnet optionally attached to the first end portion of the rotor shaft, with a north- south axis that is effectively perpendicular to the axis of rotation of the rotor shaft. In some embodiments an electrically driven hydraulic pump of the electro-hydraulic actuator may optionally include a pressure sensor that is configured and located to measure a hydraulic pressure in the electro-hydraulic actuator. The pressure measured may be a variable pressure of a variable pressure volume in the electro-hydraulic actuator. In some embodiments, an electrically driven hydraulic pump of the electro -hydraulic actuator may include one or more processors (e.g., a microprocessor-based controller sub-assembly) attached to the stator housing and in electrical communication with the stator and the pressure sensor. In some embodiments, the electrical unit may optionally be configured to be tested in combination with the microprocessor-based controller sub-assembly but independently from the associated hydraulic module. Such testing may optionally be conducted before the hydraulic module is incorporated in the electrically driven hydraulic pump. In some embodiments, the assembled electrical unit may include a hydraulic module, that is configured to be driven as a pump and / or a hydraulic motor in at least one mode of operation, where the hydraulic module includes a second shaft with a first end portion and the second end portion, where the first end portion of the second shaft is radially supported by a third bearing and the second end portion of the second shaft is radially supported by the second end portion of the rotor shaft, and where the support plate may optionally serve as the hydraulic end cap of the hydraulic module.

[0067] In some embodiments, a hydraulically sealed electro-hydraulic actuator may include an electrically driven hydraulic pump; and a hydraulically driven piston assembly; where the electrically driven hydraulic pump may be configured to be securely attached to the hydraulically driven piston assembly during operation with at least one snap ring. In some#14746377vlL0710.70106WQ00- 17 -embodiments only one snap ring may be used. In some embodiments the attachment via the one or more snap rings may be tamper proof or effectively tamper proof so that the hydraulically driven piston assembly and the electrically driven hydraulic pump may not be separated or decoupled non-destructively. Some embodiments may include an intervening manifold between the hydraulically driven piston assembly and the electrically driven hydraulic pump. In some embodiments the attachment may be achieved when the snap ring simultaneously engages a first groove in the electrically driven hydraulic pump and a second groove in the hydraulically driven piston assembly or an intervening manifold. In some embodiments, when the snap ring engages both the first and second grooves, a structurally robust, effectively tamper proof, connection is established at the same time between the hydraulically driven piston assembly and the electrically driven hydraulic pump, either directly or via the intervening manifold, which also provides properly aligned, sealed, hydraulic fluid communication channels between the hydraulically driven piston assembly and the electrically driven hydraulic pump via internal flow paths.

[0068] In one possible embodiment of the above concept, the electrically driven hydraulic pump to hydraulically driven piston assembly connection disclosed herein includes a snap-ring that is contained within a groove in the electrically driven hydraulic pump, that may engage one or more grooves (e.g., two grooves) formed in a body of a hydraulically driven piston assembly and / or in an intervening manifold, such that the axial insertion of the electrically driven hydraulic pump directly into the hydraulically driven piston assembly or into the intervening manifold allows the snap-ring to be securely constrained between the grooves, providing robust axial location and orientation. The electrically driven hydraulic pump angular location and orientation may be secured by a tab on the electrically driven hydraulic pump housing locating in a slot formed in the hydraulically driven piston assembly body or the intervening manifold, whereby, all the required hydraulic sealing interfaces -including internal pressure cavity sealing, sealing against bi-directional pressure differences from internal to external pressures and sealing from the corrosive environment are created by, for example, one or more radial sealing O-ring type seals. Any appropriate seals may be used as the disclosure is not limited in this fashion. The resulting electrically driven hydraulic pump environmental seal may advantageously block access to the snap ring and tab and slot to make the assembly tamper proof, or effectively tamper proof in some embodiments. For example, the assembly may be tamper-proof in that a user may not easily disassemble or#14746377vlL0710.70106WQ00- 18 -cause damage to the assembly. Whereby, the electrically driven hydraulic pump main subassemblies, comprising the electrical unit, the hydraulic module, and the differential buffer assembly are formed such that the electrical unit sub-assembly is a self-contained electrical unit. For example, the electrical unit may comprise components for the electrical unit to be a stand-alone and testable brushless DC motor and controller, it also may comprise part of the hydraulic module sub-assembly in as much as the electrical unit cap that locates and supports one bearing of the electrical unit sub-assembly may be configured to form a portion of the hydraulic module.

[0069] The simplified connection described herein may also result in a reduced size and weight compared to other assembly methods where, for example, threaded fasteners are used as attachment devices. The electrically driven hydraulic pump sub-assemblies, such as the electrical unit, the hydraulic module and the differential buffer assembly, may in some cases be formed to be easily and inexpensively assembled to create the electrically driven hydraulic pump, so that the electrically driven hydraulic pump may be formed to benefit from the design advantages of the electrically driven hydraulic pump, as described above. The construction of the electrically driven hydraulic pump main sub-assemblies may accommodate and facilitate each sub-assembly step, such as aligning one or more bearings of the hydraulic module, while minimizing the components and complexity to complete the subassembly steps.

[0070] In some embodiments, the electro-hydraulic actuators disclosed herein may be used as part of an automotive active suspension system. Automotive active suspension systems may include a hydraulically sealed combination of an electrically driven hydraulic pump and hydraulically driven piston assembly. Fluidic connections allow the exchange of hydraulic fluid between these two subsystems. In a hydraulically driven piston assembly, a volume on a first side of a piston, e.g. the compression side or the extension side, may be maintained at a substantially constant pressure relative to a pressure on a second side of the piston. In some cases, the first side of the piston with substantially constant pressure may be referred to as the constant pressure side of the piston while the second side may be referred to as the variable pressure side. The volume in the hydraulically driven piston assembly on the constant pressure side of the piston may have a compliance greater than that of the volume on the variable pressure side, e.g. because it is fluidly connected to an accumulator or reservoir that stabilizes the pressure.#14746377vlL0710.70106WQ00- 19 -

[0071] As used herein, an electrical unit of an electro-hydraulic actuator may be used in one or more operating modes. For example, in a first mode of operation, the electrical unit may be configured to operate as a portion of a pump to actively drive the associated hydraulic module. In such a mode of operation, the electrical unit may be configured to drive a driveshaft of any associated load coupled thereto. For example, the electrical unit may be configured to apply a current to drive a rotor and a load associated with the rotor, such as a driveshaft of a hydraulic module connected to the rotor. Thus, the rotor may be actively driven to apply a torque to the driveshaft of the attached load. The electrical unit may also be configured to operate as a generator to generate electricity in a second mode of operation when a torque is applied to the rotor by, for example, a driveshaft of the hydraulic module such that the hydraulic module of the electro-hydraulic actuator may function as a hydraulic motor. The electrical unit may include any appropriate motor, including but not limited to a brushless DC motor, stepper motor, servomotor, permanent magnet motor, brushed DC motor, synchronous motor, and any other appropriate motor as the disclosure is not limited in this fashion.

[0072] Similar to the above, a hydraulic module as used herein may be used in one or more operating modes. For example, in a first mode of operation, the hydraulic module may be configured to operate as a portion of a pump where an associated electrical unit applies a torque to drive the hydraulic module. The hydraulic module may also be operated in a second mode of operation as a portion of a hydraulic motor and may be configured to drive a driveshaft and any associated load, such as the electrical unit being operated as a generator, coupled thereto. The hydraulic module may include any appropriate pump, including but not limited to a gerotor, crescent pump, gear pump, and any other appropriate pump as the disclosure is not limited in this fashion. In some preferred embodiments, the hydraulic module may be a gerotor. The hydraulic module may be configured to be backdrivable according to some embodiments.

[0073] In view of the above, the electrical unit and the hydraulic module may be configured to operate together in the different possible modes of operation. For example, in the first mode of operation, the hydraulic module may function as a pump driven by the electrical unit. In the second mode of operation, the hydraulic module may function as a hydraulic motor that drives the electrical unit, which may function as a generator. In some cases, the electrical unit and the hydraulic motor may be configured to operate in a single#14746377vlL0710.70106WQ00- 20 -mode of operation, for example only in the first mode of operation or only in the second mode of operation. In some embodiments, the electrical unit and the hydraulic module may operate in the first and second modes of operation, or any other appropriate quantity of modes of operation.

[0074] The electro-hydraulic actuators disclosed herein may be formed from a number of subassemblies. For example, an electro-hydraulic actuator may include an electrically driven hydraulic pump fluidly coupled to a hydraulically driven piston assembly either directly or indirectly. The electrically driven hydraulic pump and the piston assembly may be coupled indirectly via a manifold or rigid tubing and / or flexible hoses. The electrically driven hydraulic pump may include an electrical unit, a hydraulic module, and optionally a differential buffer. The hydraulically driven piston assembly may include a body including a cylindrical internal volume with a piston moveably disposed in the cylindrical internal volume and a piston rod attached to the piston and extending out from at least one side of the piston and through an associated portion of the body. The volumes on either side of the piston may be fluidly coupled to the hydraulic module as elaborated on further below in relation to the figures.

[0075] Turning to the figures, specific non-limiting embodiments are described in further detail. It should be understood that the various systems, components, features, and methods described relative to these embodiments may be used either individually and / or in any functional combination as the disclosure is not limited to only the specific embodiments described herein.

[0076] A schematic representation of an exemplary embodiment of an electro-hydraulic actuator 100 is shown in Fig. 1. The electro-hydraulic actuator 100 may include a hydraulically driven piston assembly 110 having a piston 114 coupled to a piston rod 112 and slidably disposed within a cylindrical internal volume of a piston assembly body 118. The piston 114 divides the internal volume of the piston assembly body 118 into an extension volume 113 and a compression volume 116. Depending on the specific embodiment, either the compression or the extension volume may be a substantially constant pressure volume and the other of the compression and extension volume may be a variable pressure volume, though embodiments in which both volumes exhibit variable pressures are also contemplated. In some such embodiments, the electro-hydraulic actuator may include one or more pressurized accumulators Illa and / or 11 lb in fluid communication with a flow path#14746377vlL0710.70106WQ00- 21 -associated with the compression and / or extension volumes, respectively. The one or more accumulators may be configured to maintain a pressure greater than an external environmental pressure within the electro-hydraulic actuator.

[0077] The hydraulically driven piston assembly 110 may be fluidly coupled to a hydraulic module 120, as described herein. For example, the extension volume 113 may be fluidly coupled to a first hydraulic module port 122 of the hydraulic module 120 via a compression volume port 117 and the compression volume 116 may be fluidly coupled to a second hydraulic module port 124 of the hydraulic module 120 via a compression volume port 117. The ports of the electro-hydraulic actuator, including the extension volume port 115 and the first hydraulic module port 122, and the compression volume port 117 and the second hydraulic port 124 may be fluidly coupled with any appropriate type of fluid connection including but not limited to one or more hoses, rigid tubes, manifolds, direct connections, and / or any other appropriate type of connection and may include any appropriate intervening types of components such as valves, accumulators, and other fluidic components as the disclosure is not limited in this manner.

[0078] The hydraulic module 120 may be operatively coupled to an electrical unit 126 in the depicted embodiment of Fig. 1. For example, a rotor of the hydraulic module 120 may be operatively coupled to a driveshaft 128 of the electrical unit 126. As described elsewhere herein, the electrical unit 126 may form a portion of the hydraulic unit 120 of the electro-hydraulic actuator 100. During at least one or more operating modes, fluid may flow between the compression volume 116 and the extension volume 113 through the hydraulic module 120 as the piston 114 moves through the internal volume of the piston assembly body 118. As noted above, the coupled hydraulic module 120 and electrical unit 126 may be operated by an associated controller 130 including one or more processors as a pump and / or hydraulic motor depending on the specific operating mode.

[0079] An example embodiment of a stand-alone electrical unit 226 with a separate controller assembly is described in relation to Fig. 2. An electrical unit 226 may include a motor stator and a stator housing, a rotor shaft assembly, a motor rotor and a position sensor magnet, a bearing arrangement to locate and support the driveshaft assembly, a pressure sensor located in the stator housing and a separate controller (which may include the position sensor) coupled to the stator housing in some embodiments and as shown in Fig. 2. For example, as shown in the figure, a stator housing 200 may support and / or locate a support#14746377vlL0710.70106WQ00- 22 -plate 202, which may be an electrical unit cap in some embodiments. Correspondingly, the support plate 202 may radially support and locate a drive end portion of a rotor shaft 204, e.g., via a bearing radially supported in an opening formed in the support plate 202 that is sized and shaped to receive the bearing. The support plate 202 may be coupled to the stator housing 200 optionally with one or more fasteners 206. However, the support plate 202 may be coupled to the stator housing 200 in any appropriate fashion as the disclosure is not limited in this sense.

[0080] An end portion (e.g., a drive end) of the rotor shaft 204 of the electrical unit 226 may include drive features 210 that may be configured to transmit torque to and from a driveshaft of a pump element of the hydraulic module (not shown) in both clockwise and counterclockwise directions relative to an axis of rotation of the rotor shaft 204. It is noted that the only visible portion of the rotor shaft 204 in Fig. 2 is the end portion including drive features 210, and the driveshaft may be seen more clearly in the depicted embodiment of Fig.8. For example, in the depicted embodiment of Fig. 2, the drive features 210 may be keyed coupling formed as crenellations that may be configured to interlock with another keyed portion of a driveshaft associated with a hydraulic module as detailed further below. As elaborated on further below, the illustrated support plate 202, the associated bearing, and the keyed end portion of the rotor shaft 204 may be used to radially support the connected end portion of the hydraulic module driveshaft when the hydraulic module is attached.

[0081] In some embodiments, the support plate 202 may be configured to serve multiple purposes. For example, the support plate 202 may, additionally and simultaneously, form a portion (e.g., one half) of the hydraulic module (e.g., sealing plates of the hydraulic module) when the hydraulic module is assembled and attached to the electrical unit 226. For example, the support plate 202 may include a first surface 216 oriented towards the hydraulic module and a second surface opposite the first surface that is oriented away from the hydraulic module when the hydraulic module is attached to the electrical unit. The first surface of the support plate 202 may form an interior surface of a volume of the hydraulic module that is exposed to hydraulic fluid during operation of the overall electrically driven hydraulic pump. For example, in the depicted embodiment, the support plate 202 may include one or more pump port features 212 and 214 formed in the first surface 216, which may be blind ports of a gerotor, that may be configured to interface with a pump element of the hydraulic module to provide porting and pressure balancing of the pump element.#14746377vlL0710.70106WQ00- 23 -

[0082] The first surface 216 of the support plate 202 may also provide a sealing surface that one side of the pump element faces and / or seals against and may be properly shaped, positioned, and constructed (e.g., with appropriate flatness, surface finish, material, hardness, etc.) to serve as a suitable sealing plate for the hydraulic module. The support plate 202 may also include one or more piloting features 218 that may be configured to help locate the electrical unit cap 202 in and relative to the stator housing bore 220. For example, in the depicted embodiments of Figs. 2-3, the depicted protrusion corresponding to a piloting feature 218 may extend outwards from the support plate 202 and may include a curved or angled surface that is configured to help pilot (e.g., guide) the support plate 202 into a desired pose relative to the stator housing bore 220. The one or more piloting features 218 may be accessible when positioned in the stator housing bore 220 and may also be configured to help position the pump element of the hydraulic module and the hydraulic module itself, e.g., when the hydraulic module is being attached to the electrical unit. The support plate 202 may also include one or more threaded fastener holes 222 that may be used to secure the rest of the hydraulic module (not shown) to the electrical unit in some embodiments.

[0083] The stator housing 200 may also be used to support, position and / or locate one or more controller sub-assemblies 224 via any appropriate connection including, for example, a snap-fit type protrusions (not shown in Fig. 2) formed between the stator housing 200 and a controller housing 205. The snap-fit connection may be constructed so that a controller housing of an associated controller sub-assembly 224 is properly secured and located on the stator housing 200 of the electrical unit 226 when connected thereto. In some embodiments, the snap-fit connection may provide a structurally robust connection so that the controller sub-assembly 224 may be rigidly connected to the stator housing 200 to bring opposing portions of an electrical connection into contact and maintain them in contact with one another to form a functioning electrical connection between the controller and the stator (e.g., contact pads, pin connections, insulation displacement connectors). Thus, the snap-fit connection may be configured to form and maintain an appropriate electrical connection between the controller circuitry and the electrical unit, e.g., stator coils, over the life of the electrically driven hydraulic pump and anticipated forces and vibration that the electrical unit may be exposed to (e.g., during operation).

[0084] An example embodiment of a snap fit connection is shown in Fig. 4. The snap fit connection may include a first plurality of tabs 430 formed on the stator housing 200,#14746377vlL0710.70106WQ00- 24 -which may interlock into receiving notches 432 that may be formed in a second plurality of tabs 434 that may optionally be formed on the controller sub-assembly 224. Optional lead-in chamfers 436 may enable the controller sub-assembly 224 to expand over the first tabs 430 as the controller sub-assembly 224 is assembled onto the stator housing 200. An outside diameter 438 of the first tabs 430 and a bore 440 of the notches 432 may be constructed so that when the controller sub-assembly 224 is fully assembled onto the stator housing 200 and the second tabs 434 snap into place over the tabs 430, some interference may exist between the outside diameter 438 of the tabs 430 and the bore 440 of the notches 432 to provide some spring preload between the controller sub-assembly 224 and the stator housing 200. This may help to radially locate and secure the controller sub-assembly 224 onto the stator housing 200. Optionally, a first lip 442 may be formed on the tabs 430 and a second lip 444 may be formed on the notches 432 such that when the controller sub-assembly 124 is fully assembled onto the stator housing 200 and the second tabs 434 snap into place over the first tabs 430, the lips 442 and 444, may engage one another thereby axially securing and retaining the controller sub-assembly 224 relative to the stator housing 200 (e.g., in a direction which is opposite to a direction of assembly). In the depicted embodiment shown in Fig. 5, a plurality of grooves 548 formed on the stator housing 200 may axially engage with a third plurality of tabs 550 formed on the controller sub-assembly 224, for example when the controller subassembly 224 is fully assembled onto the stator housing 200, thereby axially securing and retaining the controller sub-assembly 224 relative to the stator housing 200 in the direction of assembly. As such, the controller sub-assembly 224 may be axially and radially secured and located relative to the stator housing 200.

[0085] The depicted embodiment of Fig. 6 shows an exploded view of a controller sub-assembly 224 and the electrical unit sub-assembly 226 before the controller subassembly 224 and the electrical unit sub-assembly 226 are attached according to some embodiments. As described herein, the controller sub-assembly 224 may be connected to the electrical unit sub-assembly 226 via a snap fit connection, whereby, one or more snap-fit connections may be constructed such that the one or more snap fit connection self-secure, locate, and support the controller assembly 224 relative to the stator housing 200 of the electrical unit 226. In some embodiments, this may provide a robust connection so that the controller sub-assembly 224 may be rigidly connected to the stator housing 200 without the use of separate and / or additional fasteners, e.g. threaded fasteners. In the depicted#14746377vlL0710.70106WQ00- 25 -embodiment, a snap-fit connection may be formed by the third plurality of tabs 550 formed in the controller housing 205 that may be disposed in the third plurality of slots 548 formed in the stator housing 200. The third tabs 550 may be sized and shaped to engage with the slots 548 such that the controller housing 205 is radially secured against (e.g., engaged with) the stator housing 200. This may prevent the stator housing 200 from moving in a retraction direction which is away from the controller housing 205, which may prevent the stator housing 200 from retracted away from the controller housing in the retraction direction (e.g. without deconstructing or damaging at least a portion of the assembly). The third tabs 550 and the slots 548 may also be configured to radially locate, position, and support the second tabs 434, and hence the controller sub-assembly 224, relative to the electrical unit subassembly 226, to ensure proper alignment of electrical connections between controller subassembly 224, and the electrical unit sub-assembly 226. The third tabs 550 may also be configured to align or help to align the position sensor located in the controller sub-assembly 224 relative to the position sensor target magnet located in the electrical unit sub-assembly 226 according to some embodiments.

[0086] The second tabs 434 may be formed in the controller housing 205 and may be configured to be engaged with and disposed in one or more of the same, similar, or different slots than the slots 548 formed in the stator housing 200 and may be configured such that engagement of the one or more tabs 434 with the one or more slots 548 prevents further axial insertion of the controller housing 205 onto the stator housing 200. For example, the second tabs may abut against a surface of the corresponding slots to prevent further insertion in a manner similar to that described above relative to the third tabs being configured to prevent retraction of the assembly. The second tabs 434 may also be configured to engage with one or more of the slots 548 in the same manner as (e.g., simultaneously with) the third tabs 550 engage in the slots 548, thereby axially securing the controller housing 205 onto the stator housing 200 while preventing relative movement of the controller housing 205 and stator housing 200 in both the insertion and retraction directions.

[0087] In some embodiments one or more protrusions 614 may be formed on the stator housing 200 that are received by and / or engaged with slot(s) 616 formed in the controller housing 205. The protrusion(s) 614 and the slot(s) 616 may be configured to allow the tabs 430, 434 to be engaged with the slots 548 and rotationally secure the controller housing 205 relative to the stator housing 200 in both clockwise and counterclockwise#14746377vlL0710.70106WQ00- 26 -directions. In some embodiments of an electrical unit subassembly, tabs on the stator housing and / or the controller housing engage with corresponding grooves on the other housing. This engagement may secure the stator housing axially along its insertion path into the controller housing during assembly. Additionally, protrusions on the stator housing 200 and / or the controller housing may engage with slots on the other housing to ensure the correct angular positioning of the stator housing relative to the controller housing. In some embodiments, the same element on either the controller housing or the stator housing can function both as a protrusion for angular positioning and as a tab for axial positioning. As illustrated in Fig. 21, by maintaining the appropriate angular and axial positioning of the stator housing relative to the controller housing, proper electrical contact can be made between components in the stator housing, such as for example the stator coils 551, and components in the controller housing, such as for example the printed circuit board 552, by means of one or more connectors or pins 553. For example, the stator may be rigidly held within the stator housing 200 with at least one pin connection protruding from the stator housing 200. Additionally or alternatively, by maintaining the appropriate angular and axial positioning of the stator housing relative to the controller housing, the angular position sensor magnet 820, attached to the rotor shaft 204, may be properly aligned with the position sensor which is located in controller housing and attached to, for example, the printed circuit board 552.

[0088] Therefore, once tabs 550 engage with the slots 548 the controller housing 205 may be constrained in one or more degrees of freedom relative to the stator housing 200. One or more of the protrusion, slot, tabs, and grooves may be configured and constructed to take advantage of the spring like properties of the polymer material (e.g., injection molded plastic) of the controller housing 205 to provide an interference fit when engaged according to some embodiments. The interference fit may help to provide a sufficient preload at the junctions among the protrusion, slot, tabs, and grooves which may help to secure the controller housing 205 to the stator housing 200 to resist any loads applied on the controller housing 205 relative to the stator housing 200 during operation of the electrically driven hydraulic pump. The depicted embodiment of Fig. 7 shows a close-up view of the depicted embodiment of Fig. 6 in an assembled state, which shows the protrusion 614 formed on the stator housing 200 engaged in the slot 616 formed in the controller housing 205. It should be appreciated that any snap-fit connections may be provided between two components as discussed herein and that the disclosed embodiments are not limited to any particular snap-fit connection, as any#14746377vlL0710.70106WQ00- 27 -appropriate snap-fit connection may be used, including but not limited to annular, cantilever, and / or torsional snap-fit connections as the disclosure is not so limited. Accordingly, by using one or more tabs located on the controller housing or the stator housing that engage corresponding one or more slots on the other of the controller housing and the stator housing, these housings may be easily assembled and fixed in a desired configuration relative to each other.

[0089] The depicted embodiment of Fig. 8 shows a cross-sectional view of an electrical unit sub-assembly that includes, but is not limited to, a stator housing 200, stator 804 (e.g., a brushless DC stator or other appropriate stator), a support plate (e.g., an electrical unit cap or other appropriate structure), a first bearing 830 (e.g., a roller bearing or other appropriate bearing capable of supporting a rotating shaft disposed therein), a rotor shaft assembly 808, a second bearing, a pressure sensor 812, a sealing cup 814 and a seal 844. The rotor shaft assembly 808 may include a rotor shaft 204, a rotor 818 (e.g., a brushless DC rotor), and an angular position sensor magnet 820.

[0090] The stator 804 may be rigidly and securely connected to the stator housing 200 according to some embodiments disclosed herein. There are several methods to rigidly and securely connect a brushless DC stator in a housing which enable the brushless DC stator to withstand the axial, radial and torsional loads applied to it during operation including, but not limited to: a press fit connection between an outside diameter of a stator to a bore of a housing capable of withstanding all radial and axial loads applied to the unit during operation; bonding methods with a suitable adhesive; a plurality of protrusions on the outside diameter of the stator that drivingly engage with slots in the bore of the housing; or a combination of these. It should be appreciated that the stator 804 may be coupled to the stator housing 200 in any appropriate fashion, including the aforementioned existing methods, as the disclosure is not limited in this sense.

[0091] The rotor 818 may be rigidly and securely connected to the rotor shaft 204 according to some embodiments disclosed herein. Several existing methods to rigidly and securely (e.g., substantially avoiding backlash) connect a rotor to a driveshaft may include, but are not limited to: a plurality of knurled protrusions on the driveshaft that form corresponding slots in the rotor when the rotor is pressed onto the driveshaft; thereby forming a rigid and secure connection between the rotor and driveshaft; bonding methods using a suitable adhesive; or a press fit that exists between the bore of the rotor and the outside#14746377vlL0710.70106WQ00- 28 -diameter of the driveshaft, as well as appropriate combinations thereof. It should be appreciated that the rotor 818 may be coupled to the rotor shaft 204 in any appropriate fashion, including the aforementioned existing methods, as the disclosure is not limited in this sense.

[0092] As described previously, support plate 202 (e.g., the depicted electrical unit cap or other appropriate structure) may include one or more protrusions 614 that may help to locate the support plate 202 in the stator housing bore 220. In either case, the support plate may be appropriately connected to the electrical unit to appropriately locate the bearing 830 relative to the bearing 810 as well as relative to the bore 220 of the stator 804, thereby positioning and aligning the rotor 818 relative to the stator 804. The bearing 830 may be configured to radially support a first end portion of the rotor shaft 204 configured to be coupled to a driveshaft of a hydraulic module. The bearing 810 may be configured to radially support an opposing second end portion of the rotor shaft 204. For example, in the depicted embodiment, the electrical unit may include a rotor shaft 204 with a first rotor shaft end portion radially supported by bearing 810 and a second rotor shaft end portion radially supported by bearing 830 which is connected to support plate 202. As described further below, a hydraulic module may be operatively coupled to the electrical unit such that a driveshaft 1000 of the hydraulic module is coupled to the rotor shaft 204 by an appropriate keyed connection that is configured to both radially support and rotationally couple the adjacent end portion of the driveshaft 1000 to the rotor shaft 204, see Figs. 9 and 10 detailed below. The driveshaft may also include another end portion 2362 located opposite from the coupling with the rotor shaft 204, see Fig. 21. The hydraulic module may include a third bearing 835 that is configured to radially support this second driveshaft end portion 2362. Thus, the opposing end portions of the driveshaft may be radially supported by a bearing 835 contained in the hydraulic module and the rotor shaft 204 which is radially supported by the bearing 830 connected to the support plate 202 of the electrical unit.

[0093] As described previously, the first end portion of the rotor shaft 204 may be configured to drive and / or be driven by a hydraulic motor. Accordingly, the rotor shaft 204 may include drive features 210 disposed on the first end portion that are configured to positively transmit torque to and from the pump element of the hydraulic module (not shown) in both the clockwise and counterclockwise directions relative to an axis of rotation of the rotor shaft 204 and may also include a driveshaft bore 834 that may be configured and#14746377vlL0710.70106WQ00- 29 -constructed to radially locate and support a connected end portion of a driveshaft of the pump element of the hydraulic module (not shown), and support the radial load applied by the pump element of the hydraulic module. The driveshaft drive features 210 and driveshaft bore 834 may also be configured and constructed to allow the appropriate motion and compliance between the pump element of the hydraulic module and the driveshaft assembly 808 to ensure the correct and smooth operation of the hydraulic module. The rotor shaft 204 may be formed so that the radial load applied to the driveshaft assembly 808 via the driveshaft bore 834 may be applied to the bearing 830. Therefore, the bearing 830 may be configured to have the radial load capacity to take the radial load and have sufficient life when exposed to the expected loads placed on the electrically driven hydraulic pump.

[0094] The bearing 830 and support plate 202 may be configured to axially locate and support the rotor shaft assembly 808 in a desired pose relative to the overall electrical unit. Thus, the bearing 830 may be configured to have an axial and radial load capacity to provide a desired lifespan when exposed to the expected axial and radial loads placed on the electrically driven hydraulic pump. The respective bearing fits between the bearing 830, the bearing 810, the rotor shaft assembly 808, and the respective bearing support structures may be appropriately selected such that all of the components on the driveshaft assembly 808 are axially constrained to the rotor shaft assembly 808, and the rotor shaft assembly 808 may be subsequently axially constrained to the support plate 202 and hence the electrical unit sub assembly.

[0095] The rotor shaft assembly 808 may also include an angular position sensor magnet 820 disposed on an end portion of the rotor shaft 204 opposite from the hydraulic module when the hydraulic module is attached to the electric unit. The electric unit may be configured such that the rotor shaft assembly 808 locates the angular position sensor magnet 820 in an appropriate position and angular orientation due to the corresponding locations and poses of the first and second bearings 830 and 810. Thus, the angular position sensor magnet 820 may be appropriately positioned and oriented to provide a magnetic signal related to an angular position of the driveshaft assembly 808 to a position sensor mounted in the controller sub assembly when assembled in the electrical unit.

[0096] The depicted embodiment of Fig. 9 shows a first portion of a coupling that may be used to couple a rotor shaft and driveshaft. Fig. 10 shows a second portion of the coupling that may be interlocked with the first portion of the coupling to transmit both radial#14746377vlL0710.70106WQ00- 30 -loads and rotational torques through the coupling. Specifically, Fig. 9 shows a keyed end portion of a rotor shaft 204 and Fig. 10 shows a keyed portion of a hydraulic module driveshaft 1000 that is sized and shaped to be engaged with the end portion of the rotor shaft 204 shown in Fig. 9. These portions of the coupling may be configured differently as the disclosure is not limited specifically to the details of the illustrated coupling. In the depicted embodiment, the end portion of the rotor shaft 204 may include one or more drive features 210 which may be configured to transmit torque to and from the driveshaft 1000 of the hydraulic module, in one or both of a clockwise and counterclockwise direction relative to the axis of rotation of the rotor shaft 204. For example, the one or more of the drive features 210 may be a plurality of crenelations or other protrusions extending axially from the rotor shaft 204 towards the coupled driveshaft 1000 that are sized and shaped to be received in corresponding cavities 1002 formed on a corresponding end portion of the driveshaft 1000 of the hydraulic module. The rotor shaft 204 may also include a bore 834 that extends partially through the rotor shaft 204. The bore 834, and optionally the interior faces of the drive features 210, may be sized and shaped to support an axial protrusion 1006 disposed in the bore 834. The axial protrusion 1006 may extend axially out from an end portion of the driveshaft 1000 towards the rotor shaft 204 when connected thereto. This insertion of the axial protrusion 1006 into the bore 834 may help to improve a radial load capacity of the coupling between the rotor shaft 204 and driveshaft 1000. Clearances (e.g., spaces between the components when assembled) between the drive features 210 and the cavities 1002 and between the bore 834 and the journal 1006, may be configured such that the drive shaft 1000 of the hydraulic module may move axially, radially, and articulate within an expected range relative to the rotor shaft 204. This may help accommodate radial, axial, and / or articular misalignment that may exist between the driveshaft 1000 and the rotor shaft 204. In some cases, the amount of clearance may be 0.75 mm or less, although the misalignment may be any appropriate amount as the disclosure is not limited in this manner. While a specific coupling is shown, it should be understood that other couplings for drivingly connecting a driveshaft to a rotor shaft to carry a torque and a radial load between a driveshaft and a rotor shaft, while accommodating radial and axial loads, and / or articular misalignment may be used as the disclosure is not limited in this fashion.

[0097] Referring again to Fig. 8, in some embodiments, an automotive active suspension systems may include a hydraulically sealed combination of an electrically driven#14746377vlL0710.70106WQ00- 31 -hydraulic pump and hydraulically driven piston assembly. Fluidic connections may allow the exchange of hydraulic fluid between these two subsystems. In a hydraulically driven piston assembly, the pressure on one side of the piston may be constant or relatively constant compared to the pressure on the opposite side of the piston. The side of the piston where the pressure is relatively constant may be referred to as the constant pressure side of the piston while the opposite side may be referred to as the variable pressure side. Typically, the volume in the hydraulically driven piston assembly on the constant pressure side of the piston has higher compliance than the volume on the variable pressure side, e.g. because it is fluidly connected to an accumulator that is configured to maintain a pressure in that volume within a desired range of pressures.

[0098] A pressure sensor 812 may be mounted, located, and / or secured in the stator housing 200 and may be in fluidic communication with the volume of the electrically driven hydraulic pump exposed to variable pressure via a flow path including one or more fluid passages, for example via the illustrated serially connected first fluid passage 836, second fluid passage 838 and third fluid passage 840 formed in the stator housing 200. Accordingly, the pressure sensor 812 mounted on or in the stator housing 200 may be configured to sense the variable pressure in the electrically driven hydraulic pump. The pressure sensor 812 may be rigidly and securely connected to the stator housing 200 using any appropriate type of connection. In some embodiments, when the pressure sensor 812 is connected to the stator housing 200, the pressure sensor may form an appropriate electronic connection with the controller sub-assembly in the electrical unit via electrical connections 842 which may be brought into contact with corresponding connections formed on the controller housing when the controller sub-assembly is connected to the stator.

[0099] As also shown in Fig. 8, an electrical unit sub-assembly may include a sealing cup 814 which may enclose one or more exposed surfaces (e.g., an exposed interior surface) of the stator 804 and may be sealed to the stator housing 200 by seal 844 according to some embodiments. A suitable potting compound may be injected into a gap or other cavity that is formed between the sealing cup 814 and one or both of the stator 804 and the stator housing 200. The sealing cup 814 may be configured to form a gap (e.g., a clearance gap) of an appropriate size and geometry between the sealing cup 814 and one or both of the stator 804 and the stator housing 200 so that the potting compound that may be injected into the cavity, and partially fill, effectively fill all, or fill one or more of the clearance gaps that may be#14746377vlL0710.70106WQ00- 32 -formed by (e.g., within an interior volume formed in boundaries of) the sealing cup 814, the stator 804, and / or the stator housing 200. The potting compound may be configured such that the potting compound is in contact with and supports loads applied to at least a portion of the sealing cup 814 (e.g., surfaces of the sealing cup 814 that are facing the cavity) during operation.

[0100] In the depicted embodiment, the sealing cup 814 may be closed at a distal end portion and open at a proximal end portion. The sealing cup 814 may be disposed within the stator housing 200 in a channel, such as the illustrated cylindrical cavity, extending axially at least partially through the stator 200. A gap is formed between a portion of the stator housing 200 proximate to the distal end portion of the sealing cup 814. As noted above, a potting compound may be disposed in the gap between the sealing cup 814 and the adjacent portion of the stator housing 200. Additionally, in some embodiments, the gap and associated potting compound may be present between at least a portion, and in some instances all, of an interior surface of the channel extending through the stator 804 and the adjacent portion of the sealing cup 814 extending therethrough. In some cases, a rotor assembly 808 may be disposed at least partially within, and a portion of the rotor shaft 204 may extend axially out of, an interior volume of the sealing cup 814.

[0101] As described in further detail below, the stator housing 200 may be configured and constructed with one or more appropriate injection points 1334, see Fig. 11, and air egress points 1340 to enable the potting compound to be injected into the cavity that may be formed by the sealing cup 814, the stator 804 and the stator housing 200, such that air may escape the appropriately escape cavity, for example during injection of the potting compound. For example, in some embodiments, the one or more inlets 1334 may be configured to receive and direct the potting compound into the gap between the stator housing 200 and the distal end portion of the sealing cup 814 and / or between the channel extending through the stator 804 and the sealing cup 814. In some cases, one or more outlets may be formed on the stator housing 200 and may be configured to allow air to escape from the stator housing 200 as the potting compound is directed into the stator housing. In some embodiments, the outlet may be formed on a portion of the stator housing 200 such that an orifice of the outlet is in fluid communication with the gap formed between the stator housing 200 and the distal end of the sealing cup 814. According to some embodiments, the outlet is formed such that a central axis of the outlet which is parallel to the direction of air flowing out of the stator#14746377vlL0710.70106WQ00- 33 -housing through the outlet during injection of the potting compound is parallel to an axis of rotation of the rotor shaft.

[0102] The depicted embodiment of Fig. 11 shows a close-up cross-sectional view of an embodiment of the electrical unit sub-assembly showing the bearing 810, the sealing cup 814, the stator housing 200, an air egress point 1340, and the potting compound 1102 that may penetrate into the clearance gaps formed between the sealing cup 814 and one or both of the stator housing 200 and a channel extending at least partially through the stator 804 the sealing cup 814 is disposed in as described above. As noted previously, the bearing 810 may be configured to support an end portion of the rotor shaft 204 located opposite from a driveshaft of a hydraulic module when connected thereto. Fig. 11 further illustrates how the bearing 810 may be radially located and supported by the stator housing 200 via the potting compound 1102 within the clearance formed between the stator housing 200 and the sealing cup 814. Specifically, the bearing 810 may be disposed in the sealing cup 814 in a desired position and orientation relative to the stator housing. As the gap formed between the sealing cup 814 and the stator housing 200 is filled with the potting compound 1102, the potting compound 1102 may function to maintain the bearing 810 in the desired location and orientation and radial loads applied to the support bearing 810 may pass through the sealing cup 814 to the potting compound 1102 and hence to the stator housing 200. The potting compound 1102 may be selected to have appropriate mechanical properties to support and / or transmit (e.g., disperse or absorb) radial loads applied to the sealing cup 814 from the support bearing 810.

[0103] The depicted embodiment of Fig. 12 shows an exploded view of an embodiment of a stator assembly 1200. The stator assembly 1200 may include the stator housing 200, the stator 804, the sealing cup 814, a hydraulic seal 844 and the pressure sensor 812. In some embodiments, the pressure sensor 812 may be configured to sense a pressure associated with the electrically driven hydraulic pump, including but not limited to one or more volumes with constant or variable pressures. In the embodiment shown, the stator 804 outer surface 1212 is radially supported and located in the bore 220 of the stator housing 200. For example, a plurality of axially extending protrusions 1216 on the stator 804 outer surface 1212 may be sized and shaped to be received in a plurality of receiving slots 1218 formed in the bore 220 of the stator housing 200. The receiving slots 1218 and the protrusions 1216 may be configured to maintain the stator 804 in a rotationally fixed position and orientation#14746377vlL0710.70106WQ00- 34 -within the stator housing 200. Additionally, the stator 804 may be maintained in a desired axial position due to contact between surface 1220 on the stator 804 and the surface 1222 of the stator housing 200. A press fit may exist between the stator 804 outside diameter 1212 and the bore 220 of the stator housing 200 so that the stator 804 is axially retained in the stator housing 200 both prior to and after the sealing cup 814 is assembled and the stator assembly 1200 is overmolded with the potting compound to constrain the sealing cup 814 and the stator 804 in the stator housing 200. After the stator assembly 1200 is overmolded, the hydraulic seal 844 may be assembled between the stator housing 200 and the sealing cup 814 to provide a seal therebetween. The overmolding process and sealing process are illustrated in more detail in Figs. 13A and 13B. It is noted that in some embodiments the sealing cup may be eliminated such that both the stator 804 and the rotor assembly 808 are immersed in hydraulic fluid.

[0104] The depicted embodiment of Fig. 13A shows the stator assembly 1200 with the stator 804 installed and the sealing cup 814 inserted into the stator 804, prior to an overmolding process. The stator 804 is axially located and constrained in a desired position and orientation within the stator housing 200 by corresponding surfaces 1220 formed on the stator 804 and 1222 formed on the stator housing 200 as discussed above. In some embodiments, the sealing cup 814 may be located in a desired axial position and orientation relative to the stator assembly 1200 by an overmolding fixture to form a gap 1424 between the sealing cup 814 and one or both of the stator housing 200 and an internal surface of a cylindrical cavity extending at least partially through the stator 804 as shown in the depicted embodiment of Fig. 14. The sealing cup 814 may be axially located in a desired axial position relative to the stator assembly 1200 in the overmolding fixture by supporting and locating a surface 1326 of the sealing cup 814 relative to a corresponding support surface formed in the stator housing 200 using suitable fixture constraints (e.g., clamps), as illustrated by arrows 1330 and 1332 according to some embodiments. With the stator 804 and the sealing cup 814 assembled into the stator housing 200, the stator assembly 1200 may be overmolded using a suitable potting compound 1102.

[0105] In some embodiments, the overmolding can be achieved by injecting the potting compound 1102 through one or more injection points, for example, the annual gap formed between stator electrical pins 553 and receiving holes 1336 in the stator housing 200, so that the potting compound 1102 flows into the cavity that is formed between the sealing#14746377vlL0710.70106WQ00- 35 -cup 814, the stator 804 and the stator housing 200 and the small gap 1424, in the inlet direction indicated by arrow 1338, so that the potting compound 1102 may be injected into the cavity to at least partially, and in some embodiments completely, fill the gaps formed between the sealing cup 814 and the stator 804 and / or the stator housing 200. The potting compound 1102 may flow, for example, through one or more inlets 1334. The potting compound 1102 may be in contact with and support at least a portion, all, or effectively all sealing cup surfaces facing the gap. As the potting compound 1102 is injected into the stator assembly 1200 in the direction of flow 1338, air trapped in the cavity formed between the sealing cup 814, the stator 804, and the stator housing 200 within the gap 1424, may escape via one or more air egress points 1340 that are formed in the stator housing 200 to allow entrapped air in the stator assembly 1200 to exit in the outlet direction shown by arrow 1342.

[0106] The depicted embodiment in Fig. 13B shows the stator assembly 1200 overmolded with the potting compound 1102 and with the hydraulic seal 844 installed, to show that the seal 844 in contact with a first sealing surface 1336 of the sealing cup 814 and a second sealing surface on the stator housing 200, thereby sealing any hydraulic fluid under pressure that may exist within the stator assembly 1200 from leaking along a boundary that may exist between the potting compound 1102 and the stator housing 200. Therefore, any hydraulic medium under pressure that may exist within the stator assembly 1200, as indicated by the arrows 1342, may be contained within a sealed internal volume at least partially formed by the sealing cup 814 such that the hydraulic fluid may not migrate from the cavity where the rotor assembly is located into the stator 804, or any of its sub components (which may include but not limited to, its windings, laminations, electrical connections etc.) or exit from the stator assembly 1200 via the receiving holes 1336 for the stator pins. Fig. 14 illustrates in detail the small gap 1424 that exists between the stator housing 200 and the sealing cup 814 that is filled with the potting compound 1102 after over molding of the stator assembly 1200.

[0107] As noted previously, according to some embodiments, an electrically driven hydraulic pump may be assembled with a hydraulically driven piston assembly, or an intervening portion of a housing which may include a manifold disposed between the electrically driven hydraulic pump and the hydraulically driven piston assembly. The connection between the electrically driven hydraulic pump and the hydraulically driven piston assembly may be a snap ring-based connection configured to provide a structurally#14746377vlL0710.70106WQ00- 36 -robust connection which may be restrained in a desired position and orientation in one or more (e.g., all) degrees of freedom. This connection may thus resist disturbing forces applied to it, for example, from separating forces generated by hydraulic pressures, shock, vibration, acceleration, and thermal mismatch. The connection may also provide one or more hydraulic sealing which may correspond to: internal pressure cavity sealing; sealing against bidirectional pressure differences from internal to external pressures; and / or sealing from a corrosive environment. The connection may also locate the electrically driven hydraulic pump relative to the actuator body of the hydraulically driven piston assembly and may provide a substantially tamper-proof connection as described herein. In some embodiments, the electrically driven hydraulic pump sub-assemblies may include the electrical unit, the hydraulic module, and a differential buffer assembly. In some embodiments, and as described previously above, the electrical unit sub-assembly may be a self-contained electrical unit which may include the components needed to be a stand-alone and testable brushless DC motor and controller.

[0108] The depicted embodiment of Fig. 15 shows an electrically driven hydraulic pump 1500 with associated sub-assemblies in an assembled state. The electrically driven hydraulic pump 1500 may include an electrical unit 1502 coupled to a hydraulic module 1504 and a differential buffer assembly 1506 coupled to the hydraulic module 1504. Optionally, one or more fasteners 1508 may be used to secure the hydraulic module 1504 to the electrical unit 1502. Also optionally, one or more fasteners 1510 may be used to secure the differential buffer assembly 1506 and hydraulic module 1504 to the electrical unit 1502. In some embodiments, fasteners 1508 may help to support the separating and disturbing forces which in some cases may be generated by the various hydraulic pressures and the acceleration and torque reaction forces between the electrical unit 1502 and the hydraulic module 1504. In some embodiments, the fasteners 1510 may help to support the separating and disturbing forces which may be generated by the various hydraulic pressures and the acceleration and torque reaction forces between the differential buffer assembly 1504 and the hydraulic module 1502 and their associated components.

[0109] In some embodiments, a snap-ring 1512 (or in some embodiments multiple snap rings) may be assembled to and contained within the electrical unit 1502 and may help to axially locate and retain the electrically driven hydraulic pump 1500 to a hydraulically driven piston assembly, as described further below. The snap-ring 1512 in the depicted#14746377vlL0710.70106WQ00- 37 -embodiment of Fig. 15 extends in a semi-circular arc and is circular in cross section, however the snap-ring 1512 may be formed with any appropriate cross sectional shape, such as ovular, rectangular, and any other appropriate shape and may extend along any desired path with a suitable shape that extends at least partially around and may be maintained on a portion of the electrically driven hydraulic pump 1500 as the disclosure is not limited by the shape or geometry of the snap ring 1512. The differential buffer manifold 1514 may include a seal groove 1518 formed on an outside diameter 1516 of the differential buffer manifold 1514 which may house and / or support a seal that may form a seal between variable pressure and constant pressure cavities within the actuator. For example, a seal, which may be supported and / or housed within the seal groove 1518 on an outer surface 1516 of the differential buffer manifold 1514 and may form a seal between a cavity having a constant pressure and a cavity having a variable pressure within a housing surrounding and extending along a length of the differential buffer.

[0110] In some embodiments, the stator housing 1520 may include a piloting surface 1522 that decreases in diameter in a direction extending into the stator housing. The piloting surface may provide radial support and help to accurately position the electrically driven hydraulic pump 1500 relative to the hydraulically driven piston assembly during assembly. In some cases, the piloting surface 1522 and the outer surface 1516 of the differential buffer manifold 1514 may provide support and optionally may help to locate the electrically driven hydraulic pump 1500 relative to the hydraulically driven piston assembly when subjected to acceleration loads and / or shock and vibration associated with the actuator (e.g., during operation of the actuator). The piloting surface 1522 may also serve as a sealing surface for a pressure seal of the electro-hydraulic actuator that may seal internal hydraulic pressure from the atmosphere according to some embodiments. The seal may also seal the internal pressure from the atmosphere, in instances of the internal pressure being below an atmospheric ambient pressure, for example in vacuum filling and bleeding of the electro-hydraulic actuator (see also Fig. 21).

[0111] The electrical unit 1502 may include a controller assembly 1524 with a controller housing 1526 configured to house and / or support one or more processors configured to control the electrical unit 1502 according to some embodiments. The controller housing 1526 may include an internal surface 1528 that may serve as a sealing surface for a seal located in the actuator according to some embodiments. The seal that may be associated#14746377vlL0710.70106WQ00- 38 -with (e.g., supported by) the internal surface 1528 may provide sealing from an external environmental, which may prevent moisture, corrosive elements, and / or contamination from entering a space in which the snap-ring 1512 and / or the pressure seal may be located, thereby helping to prevent damage to (e.g., corrosion of) the components (also see Fig. 21).

[0112] The internal surface 1528 on the controller housing 1526 may also provide radial support to the controller assembly 1524 relative to the actuator when subjected to acceleration loads and shock and vibration according to some embodiments. For example, the internal surface 1528 may assist in radially locating a journal diameter of a housing associated with the hydraulically driven piston assembly. In some embodiments, the controller housing 1526 may be constructed of any appropriate polymer (e.g., an injection molded plastic) which may be sufficiently deformable and / or elastic to allow a press-fit connection between the internal surface 1528 and the journal diameter of the housing associated with the hydraulically driven piston assembly. The press-fit connection may provide a structurally rigid and robust connection between the controller assembly 1524 and the actuator which may resist acceleration loads and shock and vibration loads to help maintain electrical connections between the controller assembly 1524 and the electrical unit sub-assembly. This may, for example, help to extend the lifetime of the controller assembly 1524 and / or the electro-hydraulic actuator by reducing potential for electrical failures. In some embodiments, one or more tabs 1530 may be appropriately size, shaped, and located on the stator housing 1520 such that they may be configured to be engaged with one or more receiving slots of a housing associated with the hydraulically driven piston assembly (not shown). The one or more tabs 1530 may help to angularly locate and / or retain the electrically driven hydraulic pump 1500 relative to the housing connecting the electrically driven hydraulic pump with the hydraulically driven piston assembly. Therefore, upon insertion of the electrically driven hydraulic pump 1500 into the housing axial the snap-ring 1512 may axially fix the electrically driven hydraulic pump 1500 and the housing, and the electrically driven hydraulic pump 1500 may be located and retained in one or more (e.g., all) degrees of freedom relative to the housing. The depicted embodiment of Fig. 17 shows a close-up view of the electrical unit 1502 illustrating in further detail the one or more (e.g., a plurality) tabs 1530 that may be formed in the stator housing 1520 according to some embodiments.

[0113] The depicted embodiment of Fig. 16 shows an exploded view of the electrically driven hydraulic pump 1500, illustrating the arrangement of the electrically#14746377vlL0710.70106WQ00- 39 -driven hydraulic pump 1500 sub-assemblies according to some embodiments. Again, the electrically driven hydraulic pump 1500 may include the electrical unit 1502 which may be coupled to the hydraulic module 1504, and the hydraulic module 1504 may be coupled to the differential buffer assembly 1506, optionally via the differential buffer manifold 1514. The snap-ring may be coupled to the differential buffer manifold 1514 though embodiments in which the snap-ring is engaged with another portion of the electrically driven hydraulic pump 1500 are also contemplated.

[0114] The depicted embodiment of Fig. 18 shows the electrically driven hydraulic pump 1500 prior to assembly with a housing 1800 which may include a manifold that is assembled, integrally formed, and / or otherwise associated with the housing 1800. Thus, assembly of the electrically driven hydraulic pump 1500 with the housing 1800 may place the electrically driven hydraulic pump 1500 in fluid communication with a hydraulically driven piston assembly assembled or otherwise associated with the housing 1800. A direction of insertion of the electrically driven hydraulic pump 1500 and the snap-ring 1512 constrained in the electrically driven hydraulic pump 1500 into the housing 1800 is shown by arrow 1806. It should be appreciated, as described herein, that one or both of the electrically driven hydraulic pump 1500 and the housing 1800 may be moved in any appropriate directions to assemble the electrically driven hydraulic pump 1500 with the housing 1800. For example, the housing 1800 may be moved towards the electrically driven hydraulic pump 1500 in a direction opposite to the direction 1806 shown in the depicted embodiment of Fig. 18 to assemble the housing 1800 and the electrically driven hydraulic pump 1500 together. As such, the disclosure is not limited to any particular direction of relative movement to assemble the electrically driven hydraulic pump 1500 with the housing 1800.

[0115] The depicted embodiment of Fig. 19 shows the electrically driven hydraulic pump 1500 (with the controller housing not shown) prior to assembly to the housing 1800, showing the one or more tabs 1530 formed on the stator housing 1520 that may be received by and / or engage with one or more receiving slots 1932 formed in the housing 1800 to angularly locate and / or retain the electrically driven hydraulic pump 1500 relative to the housing 1800. It should be appreciated that both the one or more tabs 1530 and the corresponding one or more receiving slots 1932 may be formed in any appropriate geometry, including curved and / or straight edges and / or surfaces. For example, the tabs and / or slots may be formed with a cylindrical or rectangular geometry. The depicted embodiment of Fig.#14746377vlL0710.70106WQ00- 40 - 20 shows the electrically driven hydraulic pump 1500 after assembly with the housing 1800 which may also include one or more openings configured to receive a hydraulically driven piston assembly, accumulator, or other appropriate hydraulic component to be fluidly coupled to the electrically driven hydraulic pump 1500 according to some embodiments.

[0116] The depicted embodiment of Fig. 21 shows a cross-sectional view of the electrically driven hydraulic pump 1500 assembled with the housing 1800. The electrically driven hydraulic pump 1500 may be axially retained to housing 1800 by the snap ring 1512 which may be engaged in one or more grooves 2106 formed in the housing 1800 and one or more corresponding grooves 2108 formed in the stator housing 1520. The grooves may be at least partially continuous, and in some embodiments continuous, annular grooves that extend at least partially, and in some embodiments completely, around the corresponding surfaces of the electrically driven pump 1500 and housing 1800 oriented towards each other. Thus, the openings of the grooves 2106 and 2108 may be oriented towards and may be located in at least partially overlapping axial positions with each other when the electrically driven hydraulic pump 1500 and housing 1800 are fully assembled. Thus, the snap ring 1512 may be disposed between an exterior surface of the electrically driven hydraulic pump 1500 and an interior surface of a portion of the housing 1800 in the depicted grooves 2106 and 2108.

[0117] The housing 1800 may include a manifold piloting bore 2103 in the housing 1800 which may help to radially locate and support the electrically driven hydraulic pump 1500 by locating a manifold piloting surface 2118 on the stator housing 1520. A variable pressure chamber 2112 may have a variable pressure and may be sealed to the atmosphere by a variable pressure seal 2114 which may be located in a groove 2116 extending around an internal a perimeter of the housing 1800 that seals on the manifold piloting surface 2118 on the stator housing 1520 according to some embodiments. A constant pressure chamber 2120 may have a constant pressure and may be sealed from the variable pressure chamber 2112, for example, by a constant pressure seal 2122, located in a groove 2124 extending around a perimeter of the differential buffer manifold 1506 that may seal on a manifold locating bore 2128 of the housing 1800 according to some embodiments.

[0118] As elaborated on further below, the snap-ring 1512 may be disposed between and partially received in the openings of both grooves 2106 and 2108 which may axially retain the electrically driven hydraulic pump 1500 against loading generated by the constant pressure acting on the area formed by the constant pressure seal 2122 and by the loading#14746377vlL0710.70106WQ00- 41 -generated by the variable pressure acting on the area formed between the constant pressure seal 2122 and the variable pressure seal 2114 according to some embodiments. The loading generated by the constant pressure acting on the area formed by the constant pressure seal 2122 and the loading generated by the variable pressure acting on the area formed between the constant pressure seal 2122 and the variable pressure seal 2114 may act in a separating direction indicated by arrow 2130 according to some embodiments. In some embodiments, the snap-ring 1512 and grooves 2106, 2108 may enable some (e.g., free / unrestricted) movement of the electrically driven hydraulic pump 1500 in the direction of the housing 1800 indicated by arrow 2132 that may be restricted due to the force from the constant pressure volume biasing the electrically driven hydraulic pump 1500 and housing 1800 towards a predetermined locked configuration. Thus, in some embodiments, an internal volume may be formed between the housing portion and the electrically driven hydraulic pump and may be configured to be pressurized. In some cases, when pressure is applied to this internal volume the first housing portion may be biased towards a predetermined locked configuration relative to the snap ring and the electrically driven hydraulic pump.

[0119] In some embodiments, an electrically driven hydraulic pump 1500 may include a hydraulically driven piston assembly operatively received in a first housing portion and a first radially extending at least partially continuous annular groove associated with the electrically driven hydraulic pump. According to some embodiments, the electro-hydraulic actuator may further include a second radially extending at least partially continuous annular groove associated with the first housing portion and a first opening of the first groove may be oriented towards and located in an at least partially overlapping axial position with a second opening of the second groove. A snap ring may be disposed between and received in the first and second openings of the first groove and the second groove according to some embodiments. In some cases, when assembled in the electro-hydraulic actuator, the snap ring may prevent movement of the first housing portion and the electrically driven hydraulic pump along an axis of insertion. In some cases, one or both of the first and second radially extending at least partially continuous annular grooves may be entirely continuous.

[0120] In some embodiments, such as the depicted embodiment of Fig. 21, an environmental seal 2134 may be located in a groove 2136 in the housing 1800 that seals on the controller housing locating bore 2138 of the controller housing 1526 to reduce or prevent the ingress of external elements (e.g., moisture) to prevent corrosion and contamination. Also#14746377vlL0710.70106WQ00- 42 -shown in the depicted embodiment of Fig. 21 are one or more fasteners 1508 which may optionally be included to secure the electrical unit 1500 to the stator housing 1520. The fasteners 1508 may also secure one or more components of the hydraulic module 1500, including a hydraulic module spacer 2148 and the differential buffer manifold 1514 to retain their position relative to the support plate 2152 (e.g., an electrical unit cap) of the electrical unit 1500 after tip- set and the bearing-to-bearing assembly operations have been carried out according to some embodiments. The fasteners 1508 may also help secure the hydraulic module subcomponents and the support plate 2152 to the electrical unit 1500 to resist the loads placed upon the hydraulic module and the electrical unit from forces generated by the various hydraulic pressures acting on their effective areas as well as acceleration, shock, and vibration forces.

[0121] The depicted embodiment of Fig. 21 also shows a pump element 2154 (shown in greater detail in Fig. 22) which may be operatively coupled to (e.g., torsionally connected to) the electrical unit rotor shaft by one or more drive features 210 which may be configured to form a keyed connection between an end portion of a rotor shaft 204 (shown in greater detail in Fig. 9) and cavities 2160 located in the pump element 2154 (e.g., inner gerotor pump element). The keyed connection may also be configured to radially locate and constrain the inner gerotor pump element 2154 relative to the electrical unit driveshaft 204 using a portion of the driveshaft, such as the illustrated axial projection 2162 extending out from a driveshaft of the inner gerotor pump element 2154, received in a bore 834 formed in the electrical unit rotor shaft 2158. The other opposing end portion of the drive shaft of the pump element 2154 may radially constrained in a bearing located in the hydraulic module manifold. The keyed fit between the drive features 210 and cavities 2160 and the projection 2362 extending from an end portion of the driveshaft and bore 834 and the opposing end portion 2362 of the drive shaft journal and the bearing may allow for freedom of motion for the pump element 2154 to axially float so that it is axially located between the hydraulic module manifold and the electrical unit cap 2152 and to allow enough compliance in the connection of the between the electrical unit driveshaft 204 and the inner gerotor pump element 2154 to allow for any misalignment from the natural dimensional and assembly tolerances that exist within the hydraulic module and electrical unit assemblies.

[0122] The depicted embodiment of Fig. 9 shows an end portion of the rotor shaft 204 of Fig. 21 according to some embodiments. Fig. 23 shows the pump element 2154 of Fig. 21#14746377vlL0710.70106WQ00- 43 -according to some embodiments, which in some cases may be formed as an inner gerotor pump element and may correspond to and be configured to engage with the end portion of the driveshaft 204 shown in Fig. 9. The depicted connection formed by opposing portions of the rotor shaft 204 and drive shaft of the pump element 2154 is similar to that described above relative to Figs. 9 and 10. In the depicted embodiment, the end portion of the driveshaft of the pump element 2154 may include one or more axial protrusions 2362 and one or more cavities 2360. In some embodiments, the pump element 2154 may include an overmolded portion 2372, which in the depicted embodiment of Fig. 23 is shaped to form the lobes of a gerotor or other rotary portion of a hydraulic module. The rotor shaft end portion 204 may include one or more (e.g., four) drive features 2256, such as the depicted axially extending protrusions, and a bore 834 extending partially into the rotor shaft 204. The bore 834 and drive features 210 may be configured to be engaged with the axial protrusion 2362 and the one or more cavities 2360 of the driveshaft of the pump element 2154. The depicted embodiments of Figs.23-24 show cross-sectional views of an end portion of the rotor shaft 204 and an adjacent end portion of the drive shaft of the pump element 2154 coupled to one another. Thus, in the depicted embodiment, the rotor shaft 204 may include a first rotor shaft end portion and a second rotor shaft end portion which may include a keyed portion configured to interlock with and radially support a corresponding keyed portion of a driveshaft of the hydraulic module (e.g., the coupling formed between the rotor shaft 204 and the driveshaft of the pump element 2154). In some cases, the keyed portion of the first driveshaft may be configured to be at least partially received within the second rotor shaft end portion.

[0123] The depicted embodiment of Fig. 25 shows a constant pressure area 2572 of a constant pressure chamber 2520 that may be formed by the constant pressure seal 2122 as well as a variable pressure annular area 2574 of the variable pressure chamber 2512 that may be formed between a variable pressure seal 2514 and the constant pressure seal 2122. During operation of the actuator, there may be a constant pressure and a variable pressure generated which may act upon the constant pressure area 2572 and variable pressure annular area 2574, respectively. The constant pressure and variable pressure pressures acting over the constant pressure area 2572 and variable pressure annular area 2574 respectively may generate axial forces on the electrically driven hydraulic pump 1500 in a direction parallel to arrow 2530 in relation to the housing 1800. The magnitude of the axial force may in some cases be the sum of the constant pressure acting over the constant pressure area 2572 with the variable pressure#14746377vlL0710.70106WQ00- 44 -acting over variable pressure annular area 2574. The resulting axial force applied between the electrically driven hydraulic pump 1500 and the housing 1800 may hold the snap ring 1512 in a locked configuration against the grooves formed in the stator housing 1520 and in the housing 1800.

[0124] The depicted embodiments of Figs. 26A-27D show various views and stages of an example assembly sequence of an electrically driven hydraulic pump 1500 into a housing 1800 according to some embodiments. The snap-ring 1512 may be constrained within the electrically driven hydraulic pump 1500 prior to, during and after assembly of the electrically driven hydraulic pump 1500 into the housing 1800.

[0125] The depicted embodiment of Fig. 26A-26C show a snap-ring 1512 constrained within the electrically driven hydraulic pump 1500 (e.g., within a controller assembly housing 1526 on a stator housing 1520) prior to assembly with the housing 1800. The snapring 1512 may be axially constrained within the electrically driven hydraulic pump 1500 prior to assembly into the housing 1800 by a plurality of tabs 2608 that may be formed on the controller housing 1526 of electrically driven hydraulic pump 1500 and a groove 2610 that may be an at least partially continuous annular groove that extends at least partially, and in some embodiments completely, around a perimeter of the stator housing 1520. The snap-ring 1512 may be biased towards a predetermined radial configuration around the stator housing 1520 prior to assembly into housing 1800 by a plurality of flexible fingers 2614 that may be coupled to the controller housing 406 of the electrically driven hydraulic pump 1500. The plurality of flexible fingers 2614 may also be configured to contact the snap ring and bias the snap ring towards a locked configuration. In some cases, the plurality of flexible fingers 2614 may be configured to contact an interior surface of the snap ring 1512 to bias the snap ring 1512 in an outward radial direction as illustrated in the figure, but embodiments in which the flexible figures or another appropriate construction is used to bias the snap ring 1512 in an inward direction are also contemplated. The flexible fingers 2614 may also be constructed so they will radially support and locate the snap ring 1512 in a desired pose when it is in its free state (e.g., before assembly of the electrically driven hydraulic pump 1500 into housing 1800) and may flex radially inward when the snap ring 1512 is being radially compressed during assembly into the housing 1800.

[0126] Figs. 27A-27D illustrate show one embodiment of an assembly process of an electrically driven hydraulic pump 1500 and a housing 1800. In the depicted embodiment the#14746377vlL0710.70106WQ00- 45 -snap-ring 1512 is radially compressed by a camming surface such as the depicted chamfer 2616 on the bore of the housing 1800 as the electrically driven hydraulic pump 1500 is assembled into housing 1800 along an axis of insertion aligned with the direction of arrow 2618. In some embodiments, the tabs 2608 may axially retain the snap ring 1512 relative to the electrically driven hydraulic pump 1500 during insertion. Accordingly, the camming surface forces the snap ring 1512 to radially compress as the electrically driven hydraulic pump 1500 is assembled into housing 1800. The tabs 2608 may keep the snap ring 1512 axially aligned with the snap ring groove 2610 formed in the stator housing 1520 or another appropriate portion of the electrically driven hydraulic pump 1500. Therefore, the snap ring 1512 may be radially compressed into the snap ring groove 2610 and out of a path of movement of the portion of the housing 1800 being inserted into the electrically driven hydraulic pump 1500. Correspondingly, the flexible fingers 2614 (not shown in this figure) may flex inward as described previously as the snap ring 1512 is being radially compressed inwards.

[0127] Fig. 27B shows the electrically driven hydraulic pump 1500 assembled into the housing 1800 so that an opening of another snap ring groove 2620 formed in the housing 1800 is axially aligned with the snap ring 1512 and is located in an at least partially overlapping axial position with an opening of the snap ring groove 2610 formed in the stator housing 1520. Fig. 27C shows the snap ring 1512 expanding radially (under its own snap ring spring force and / or in response to a biasing force applied by the one or more flexible fingers 2614 or other appropriate biasing component as described above). This causes the snap ring 1512 to expand partially out of the snap ring groove 2610 and partially into the snap ring groove 2620 once the electrically driven hydraulic pump 1500 is assembled into housing 1800 so that the snap ring 1512 is axially aligned with an opening of the snap ring groove 2620 that is formed into the housing 1800 and oriented towards an opening of the groove 2610 formed in the stator housing 1520.

[0128] As noted previously, a pressure applied to one or more internal volumes contained between the housing 1800 and electrically driven hydraulic pump 1500 may result in a separation force that biases these subassemblies away from one another. Fig. 27D shows the electrically driven hydraulic pump 1500 has been partially retracted out of the housing 1800 in the direction of the arrow 2622 as might occur in response to this separation force. This may bring the snap ring 1512 into axial engagement with one or more correspondingly#14746377vlL0710.70106WQ00- 46 -shaped portions of the snap ring groove 2610 and the snap ring groove 2620 located on opposing sides of the snap ring. This may compress the snap ring between the two grooves which may maintain the electrically driven hydraulic pump 1500 in a desired axial location relative to the housing 1800 by preventing further separation of the electrically driven hydraulic pump 1500 and the housing 1800 in an axial direction aligned with the direction of insertion. As most electro-hydraulic actuators are maintained with a minimum operating pressure within a constant pressure volume, this may maintain the electrically driven hydraulic pump 1500 and the housing 1800 in a predetermined locked configuration with a predetermined axial location of these subassemblies relative to one another.

[0129] Exemplary Embodiments

[0130] Embodiment 1 : An electrically driven hydraulic pump of an electro-hydraulic actuator, comprising: a stator housing; an electrical unit, located in a cavity in the stator housing, that includes a stator, an electric motor rotor shaft, with an axis of rotation, that has a first end and a second end, wherein the first end is radially supported by a first bearing and the second end is radially supported by a second bearing; a support plate that supports the second bearing; and a target magnet, attached to the first end of the rotor shaft, with a northsouth axis that is effectively perpendicular to the axis of rotation of the rotor shaft.

[0131] Embodiment 2: The electrically driven hydraulic pump of embodiment 1, further comprising a pressure sensor configured and located to measure a hydraulic pressure in the electro-hydraulic actuator.

[0132] Embodiment 3: The electrically driven hydraulic pump of embodiment 2, further comprising a microprocessor-based controller sub-assembly attached to the stator housing and in electrical communication with the stator.

[0133] Embodiment 4: The electrically driven hydraulic pump of embodiment 3, wherein the microprocessor-based controller sub-assembly is also in electrical communication with the pressure sensor.

[0134] Embodiment 5: The electrically driven hydraulic pump of embodiment 4, wherein the electrical unit is configured to be tested in combination with the microprocessorbased controller sub-assembly but independently from a hydraulic module.

[0135] Embodiment 6: An apparatus according to embodiments 1-4, further comprising a hydraulic module that is configured to be operated as a pump, wherein the hydraulic module includes a second shaft with a first end and the second end, wherein the#14746377vlL0710.70106WQ00- 47 -first end of the second shaft is radially supported by a third bearing and the second end of the second shaft is radially supported by the second end of the rotor shaft, and wherein the support plate also serves as the hydraulic end cap of the hydraulic module.

[0136] Embodiment 7: A hydraulically sealed electro-hydraulic actuator, comprising: an electrically driven hydraulic pump; and a hydraulically driven piston assembly; wherein the electrically driven hydraulic pump is configured to be securely attached to the hydraulically driven piston assembly, during a first mode of operation, with at least one snap ring.

[0137] Embodiment 8: The hydraulically sealed electro -hydraulic actuator of embodiment 7, wherein the at least one snap ring is a single snap ring.

[0138] Embodiment 9: A hydraulically sealed electro-hydraulic actuator according to embodiments 7-8, wherein the electrically driven hydraulic pump and the hydraulically driven piston assembly cannot be non-destructively decoupled.

[0139] Embodiment 10: A hydraulically sealed electro-hydraulic actuator according to embodiments 7-9, further comprising an intervening manifold located between the electrically driven hydraulic pump and the hydraulically driven piston assembly.

[0140] Embodiment 11 : The hydraulically sealed electro-hydraulic actuator of embodiment 10, further comprising at least a first groove that is incorporated in the electrically driven hydraulic pump and at least a second groove that is incorporated in the manifold, wherein snap ring is configured and positioned to engage the first groove and the second groove during at least one mode of operation.

[0141] Embodiment 12: The hydraulically sealed electro-hydraulic actuator of embodiment 11, wherein the electrically driven hydraulic pump and the hydraulically driven piston assembly are configured and position such that when the snap ring has engaged both the first groove and the second groove, a structurally robust, effectively tamper proof, connection is established between the electrically driven hydraulic pump and the hydraulically driven piston assembly via the intervening manifold that provides sealed, hydraulic fluid communication, via flow paths in the intervening manifold, between the electrically driven hydraulic pump and the hydraulically driven piston assembly.

[0142] While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various#14746377vlL0710.70106WQ00- 48 -alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art. Accordingly, the foregoing description and drawings are by way of example only.

[0143] The above-described embodiments of the technology described herein may be implemented in any of numerous ways. For example, the embodiments may be implemented using hardware, software or a combination thereof. When implemented in software, the software code may be executed on any suitable processor or collection of processors, whether provided in a single computing device or distributed among multiple computing devices. Such processors may be implemented as integrated circuits, with one or more processors in an integrated circuit component, including commercially available integrated circuit components known in the art by names such as CPU chips, GPU chips, microprocessor, microcontroller, or co-processor. Alternatively, a processor may be implemented in custom circuitry, such as an ASIC, or semicustom circuitry resulting from configuring a programmable logic device. As yet a further alternative, a processor may be a portion of a larger circuit or semiconductor device, whether commercially available, semi-custom or custom. As a specific example, some commercially available microprocessors have multiple cores such that one or a subset of those cores may constitute a processor. Though, a processor may be implemented using circuitry in any suitable format. It should also be understood that any reference to a controller in the current disclosure may be understood to reference the use of one or more processors configured to implement the one or more methods disclosed herein.

[0144] Further, it should be appreciated that a computing device including one or more processors may be embodied in any of a number of forms, such as a rack-mounted computer, a desktop computer, a laptop computer, or a tablet computer. Additionally, a computing device may be embedded in a device not generally regarded as a computing device but with suitable processing capabilities, including a Personal Digital Assistant (PDA), a smart phone, tablet, or any other suitable portable or fixed electronic device.

[0145] Also, a computing device may have one or more input and output devices. These devices may be used, among other things, to present a user interface. Examples of output devices that may be used to provide a user interface include display screens for visual presentation of output and speakers or other sound generating devices for audible presentation of output. Examples of input devices that may be used for a user interface include keyboards, individual buttons, and pointing devices, such as mice, touch pads, and#14746377vlL0710.70106WQ00- 49 -digitizing tablets. As another example, a computing device may receive input information through speech recognition or in other audible format.

[0146] Such computing devices may be interconnected by one or more networks in any suitable form, including as a local area network or a wide area network, such as an enterprise network or the Internet. Such networks may be based on any suitable technology and may operate according to any suitable protocol and may include wireless networks, wired networks or fiber optic networks. Also, the various methods or processes outlined herein may be coded as software that is executable on one or more processors that employ any one of a variety of operating systems or platforms. These methods may be embodied as processor executable instructions stored on associated non-transitory computer readable media that when executed by the one or more processors perform any of the methods disclosed herein. Additionally, such software may be written using any of a number of suitable programming languages and / or programming or scripting tools, and also may be compiled as executable machine language code or intermediate code that is executed on a framework or virtual machine.

[0147] In this respect, the embodiments described herein may be embodied as a computer readable storage medium (or multiple computer readable media) (e.g., a computer memory, one or more floppy discs, compact discs (CD), optical discs, digital video disks (DVD), magnetic tapes, flash memories, RAM, ROM, EEPROM, circuit configurations in Field Programmable Gate Arrays or other semiconductor devices, or other tangible computer storage medium) encoded with one or more programs that, when executed on one or more computers or other processors, perform methods that implement the various embodiments discussed above. As is apparent from the foregoing examples, a computer readable storage medium may retain information for a sufficient time to provide computer-executable instructions in a non-transitory form. Such a computer readable storage medium or media may be transportable, such that the program or programs stored thereon may be loaded onto one or more different computing devices or other processors to implement various aspects of the present disclosure as discussed above. As used herein, the term "computer-readable storage medium" encompasses only a non- transitory computer-readable medium that may be considered to be a manufacture (i.e., article of manufacture) or a machine. Alternatively or additionally, the disclosure may be embodied as a computer readable medium other than a computer-readable storage medium, such as a propagating signal.#14746377vlL0710.70106WQ00- 50 -

[0148] The terms “program” or “software” are used herein in a generic sense to refer to any type of computer code or set of computer-executable instructions that may be employed to program a computing device or other processor to implement various aspects of the present disclosure as discussed above. Additionally, it should be appreciated that according to one aspect of this embodiment, one or more computer programs that when executed perform methods of the present disclosure need not reside on a single computing device or processor but may be distributed in a modular fashion amongst a number of different computers or processors to implement various aspects of the present disclosure.

[0149] Computer-executable instructions may be in many forms, such as program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Typically, the functionality of the program modules may be combined or distributed as desired in various embodiments.

[0150] The embodiments described herein may be embodied as a method, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[0151] While the present teachings have been described in conjunction with various embodiments and examples, it is not intended that the present teachings be limited to such embodiments or examples. On the contrary, the present teachings encompass various alternatives, modifications, and equivalents, as will be appreciated by those of skill in the art. Accordingly, the foregoing description and drawings are by way of example only.#14746377vl

Claims

1. L0710.70106WQ00- 51 - CLAIMS1. An electrical unit comprising:a rotor shaft with a first rotor shaft end portion and a second rotor shaft end portion;a bearing configured to radially support the rotor shaft at the second rotor shaft end portion; anda support plate with a first surface and a second surface opposite the first surface, wherein the support plate is configured to radially support the bearing, wherein the first surface of the support plate is configured to form an interior surface of a volume of a hydraulic module that is exposed to hydraulic fluid during operation when the hydraulic module is attached to the electrical unit, and wherein the electrical unit is configured to operate as an electrical motor in a first mode of operation.

2. The electrical unit of claim 1, wherein the electrical unit is configured to operate as a generator in a second mode of operation.

3. The electrical unit of any one of claims 1-2, wherein the support plate includes one or more blind ports of the hydraulic module formed therein.

4. The electrical unit of any one of claims 1-3, wherein the second rotor shaft end portion includes a keyed portion, and wherein the keyed portion is configured to interlock with and radially support a corresponding keyed portion of a driveshaft of the hydraulic module.

5. The electrical unit of claim 4, wherein the keyed portion of the second rotor shaft end portion is configured to receive at least a portion of an end portion of the driveshaft therein.

6. The electrical unit of any one of claims 1-5, wherein the support plate is configured to form an end cap of the hydraulic module.#14746377vlL0710.70106WQ00- 52 - 7. The electrical unit of any one of claims 1-6, further comprising a target magnet attached to the first rotor shaft end portion with a north-south axis that is substantially perpendicular to an axis of rotation of the rotor shaft.

8. The electrical unit of any one of claims 1-7, wherein the support plate is a cap of the hydraulic module.

9. The electrical unit of any one of claims 1-8, further comprising an opening in the support plate sized and shaped to receive the bearing.

10. The electrical unit of any one of claims 1-9, wherein the electrical unit is an electric motor.

11. The electrical unit of any one of claims 1-10, wherein the electrical unit is configured to be operated as an electric motor independently of the hydraulic module prior to assembly.

12. An electrically driven hydraulic pump comprising:the electrical unit of any one of claims 1-11; andthe hydraulic module operatively coupled to the electrical unit, wherein the hydraulic module is configured to operate as a pump in the first mode of operation.

13. The electrically driven hydraulic pump of claim 12, wherein the hydraulic module is configured to operate as a hydraulic motor in a second mode of operation.

14. The electrically driven hydraulic pump of any one of claims 12-13, wherein the hydraulic module includes a gerotor.

15. An electro-hydraulic actuator comprising:a body including an internal volume;a piston slidably received in the internal volume of the body, wherein the piston divides the internal volume into a first volume and a second volume; and#14746377vlL0710.70106WQ00- 53 - the electrically driven hydraulic pump of any one of claims A9-A11, wherein a first port of the electrically driven hydraulic pump is in fluid communication with the first volume and a second port of the electrically driven hydraulic pump is in fluid communication with the second volume.

16. An electrically driven hydraulic pump comprising:an electrical unit configured to be operated as an electrical motor in a first mode of operation, the electrical unit comprising:a rotor shaft having a first rotor shaft end portion and a second rotor shaft end portion;a first bearing configured to radially support the first end portion of the rotor shaft;a second bearing configured to radially support the second end portion of the rotor shaft; anda support plate configured to support the second bearing;a hydraulic module that is configured to be operated as a pump in the first mode of operation, the hydraulic module comprising:a driveshaft including a first driveshaft end portion and a second driveshaft end portion; anda third bearing configured to radially support the second driveshaft end portion, wherein the first driveshaft end portion is operatively torsionally coupled to the second rotor shaft end portion and wherein the first driveshaft end portion is radially supported by the second end portion of the rotor shaft.

17. The electrically driven hydraulic pump of claim 16, wherein the electrical unit is configured to operate as a generator and the hydraulic module is configured to operate as a hydraulic motor in a second mode of operation.

18. The electrically driven hydraulic pump of any one of claims 16-17, wherein the support plate includes one or more blind ports of the hydraulic module formed therein.#14746377vlL0710.70106WQ00- 54 - 19. The electrically driven hydraulic pump of any one of claims 16-18, wherein the hydraulic module is a gerotor.

20. The electrically driven hydraulic pump of any one of claims 16-19, wherein the second end portion of the rotor shaft includes a keyed portion, and wherein the keyed portion is configured to torsionally interlock with and radially support a corresponding keyed portion of the first driveshaft end portion.

21. The electrically driven hydraulic pump of any one of claims 16-20, wherein the first driveshaft end portion is configured to be at least partially received within the second rotor shaft end portion.

22. The electrically driven hydraulic pump of any one of claims 16-21, wherein the support plate is configured to form a cap of the hydraulic module.

23. The electrically driven hydraulic pump of any one of claims 16-22, further comprising a pressure sensor configured to sense a pressure associated with the electrically driven hydraulic pump.

24. The electrically driven hydraulic pump of any one of claims 16-23, further comprising a target magnet attached to the first end rotor shaft end portion with a north- south axis that is substantially perpendicular to an axis of rotation of the rotor shaft.

25. An electro-hydraulic actuator comprising:a body including an internal volume;a piston slidably received in the internal volume of the body, wherein the piston divides the internal volume into a first volume and a second volume; andthe electrically driven hydraulic pump of any one of claims 16-24, wherein a first port of the electrically driven hydraulic pump is in fluid communication with the first volume and a second port of the electrically driven hydraulic pump is in fluid communication with the second volume.#14746377vlL0710.70106WQ00- 55 - 26. A method of operating an electrically driven hydraulic pump, the method comprising:supporting a rotor shaft of an electrical unit with a bearing;supporting the bearing with a support plate; anddriving a driveshaft of a hydraulic module with the rotor shaft in a first mode of operation, wherein the support plate forms an interior surface of a hydraulically sealed volume of the hydraulic module that is exposed to hydraulic fluid during operation of the electrically driven hydraulic pump.

27. The method of claim 26, further comprising operating the electrical unit as a generator and the hydraulic module as a hydraulic motor in a second mode of operation.

28. The method of any one of claims 26-27, wherein the support plate includes one or more blind ports of the hydraulic module formed therein.

29. The method of any one of claims 26-28, wherein the hydraulic module is a gerotor.

30. The method of any one of claims 26-29, furthering comprising torsionally interlocking and radially supporting a keyed portion of the driveshaft with a keyed portion of the second rotor shaft end portion.

31. The method of claim 30, further comprising at least partially receiving a portion of the driveshaft within the second rotor shaft end portion.

32. The method of any one of claims 26-31, further comprising forming a cap of the hydraulic module with the support plate.

33. The method of any one of claims 26-32, further comprising sensing a pressure associated with the electrically driven hydraulic pump.

34. The method of any one of claims 26-33, further comprising sensing a signal from a target magnet disposed on the rotor shaft with a north-south axis that is substantially perpendicular to an axis of rotation of the rotor shaft.#14746377vlL0710.70106WQ00- 56 -35. The method of any one of claims 26-34, further comprising:flowing a hydraulic fluid between a first volume disposed on a first side of a piston and a second volume disposed on a second side of a piston through the electrically driven hydraulic pump.

36. A method of operating an electrically driven hydraulic pump, the method comprising:radially supporting a first rotor shaft end portion of a rotor shaft of an electrical unit, with a first bearing;radially supporting a second end portion of the rotor shaft with a second bearing; radially supporting and torsionally coupling a first end portion of a driveshaft of a hydraulic module with the second end portion of the rotor shaft; andin a first mode of operation torsionally driving the driveshaft of the hydraulic module with the rotor shaft.

37. The method of claim 36, further comprising operating the electrical unit as a generator and the hydraulic module as a hydraulic motor in a second mode of operation.

38. The method of any one of claims 36-37, furthering comprising interlocking and radially supporting a keyed portion of the driveshaft with a keyed portion of the rotor shaft.

39. The method of any one of claims 36-38, further comprising at least partially receiving a portion of the driveshaft within the second end portion of the rotor shaft.

40. The method of any one of claims 36-39, further comprising sensing a pressure associated with the electrically driven hydraulic pump.

41. The method of any one of claims 36-40, further comprising sensing a signal from a target magnet attached to the first end portion of the rotor shaft with a north- south axis that is substantially perpendicular to an axis of rotation of the rotor shaft.#14746377vlL0710.70106WQ00- 57 - 42. The method of any one of claims 36-41, further comprising forming a cap of the hydraulic module with the support plate.

43. The method of any one of claims 36-41, further comprising:flowing a hydraulic fluid between a first volume disposed on a first side of a piston and a second volume disposed on a second side of a piston through the electrically driven hydraulic pump.

44. The method of any one of claims 36-43, further comprising radially supporting the second bearing with a support plate of the electrical unit.

45. The method of any one of claims 36-44, further comprising driving the rotor shaft with the driveshaft in a second mode of operation.

46. An electrical unit comprising:a stator housing;a stator disposed in the stator housing;a sealing cup closed at a distal end portion and open at a proximal end portion, wherein the sealing cup is disposed within the stator housing in a cylindrical cavity extending axially through the stator such that a gap is formed between a portion of the stator housing and the distal end portion of the sealing cup and an interior surface of the cylindrical cavity of the stator and the sealing cup;a potting compound disposed in the gap between the portion of the stator housing and the distal end portion of the sealing cup and the interior surface of the cylindrical cavity of the stator and the sealing cup; anda rotor disposed at least partially within an interior volume of the sealing cup.

47. The electrical unit of claim 46, further comprising at least one inlet formed on the stator housing configured to receive and direct the potting compound into the gap between the stator housing and the distal end of the sealing cup.#14746377vlL0710.70106WQ00- 58 - 48. The electrical unit of any one of claims 46-47, wherein a portion of the gap is formed between the stator and the sealing cup, and the potting compound is disposed in the gap between the stator and the sealing cup.

49. The electrical unit of any one of claims 46-48, further comprising an outlet formed on the stator housing configured to allow air to escape from the stator housing as the potting compound is directed into the stator housing.

50. The electrical unit of claim 49, wherein the outlet is formed on a portion of the stator housing such that an orifice of the outlet is coupled to the gap formed between the stator housing and the distal end of the sealing cup.

51. The electrical unit of any one of claims 49-50, wherein the outlet is formed such that a central axis of the outlet which is parallel to the direction of air flowing out of the stator housing through the outlet is parallel to an axis of rotation of the rotor shaft.

52. The electrical unit of any one of claims 46-51, further comprising a rotor shaft of the rotor disposed in and extending out of the sealing cup.

53. The electrical unit of claim 52, further comprising a first bearing configured to support a first end portion of the rotor shaft, wherein the first bearing is disposed in the sealing cup.

54. The electrical unit of claim 53, further comprising a second bearing configured to support a second end portion of the rotor shaft, wherein the second bearing is radially supported by a support plate coupled to the stator housing.

55. An electrically driven hydraulic pump comprising:a hydraulic module that is configured to be operated as a pump in the first mode of operation; andthe electrical unit of any one of claims 46-54.#14746377vlL0710.70106WQ00- 59 - 56. An electro-hydraulic actuator comprising:a body including an internal volume;a piston slidably received in the internal volume of the body, wherein the piston divides the internal volume into a first volume and a second volume; andthe electrically driven hydraulic pump of claim 55, wherein a first port of the electrically driven hydraulic pump is in fluid communication with the first volume and a second port of the electrically driven hydraulic pump is in fluid communication with the second volume.

57. A method for manufacturing an electrical unit, the method comprising:positioning a sealing cup into a cylindrical cavity extending axially through a stator to form a gap between a closed distal end potion of the sealing cup and a stator housing of the stator and between the sealing cup and the internal surface of the cylindrical cavity; and filling the gap with a potting compound.

58. The method of claim 57, further comprising receiving and directing the potting compound into the gap via an inlet formed on the stator housing.

59. The method of any one of claims 57-58, further comprising flowing air from the gap through an outlet formed on the stator housing as the gap is filled with the potting compound.

60. The method of claim 59, wherein the outlet is formed on a portion of the stator housing such that an orifice of the outlet is coupled with the gap.

61. The method of any one of claims 59-60, wherein flowing the air through the outlet includes flowing the air out of the outlet in a direction parallel to an axis of rotation of the rotor shaft.

62. The method of any one of claims 57-61, further comprising positioning a rotor at least partially within the sealing cup.#14746377vlL0710.70106WQ00- 60 - 63. The method of claim 62, further comprising radially supporting a first end portion of a rotor shaft of the rotor with a first bearing disposed in the sealing cup.

64. The method of claim 63, further comprising radially supporting a second end portion of the rotor shaft with a second bearing radially supported by a support plate of the electrical unit.

65. An electro-hydraulic actuator comprising:an electrically driven hydraulic pump;a housing;a first at least partially continuous annular groove associated with the electrically driven hydraulic pump;a second at least partially continuous annular groove associated with a first portion of the housing, wherein a first opening of the first groove is oriented towards and is located in at least a partially overlapping axial position with a second opening of the second groove when the electrically driven hydraulic pump is fully inserted in the housing; anda snap ring disposed between and at least partially received in the first and second openings of the first at least partially continuous annular groove and the second at least partially continuous annular groove, wherein when assembled in the electro-hydraulic actuator, the snap ring prevents relative movement between the housing and the electrically driven hydraulic pump along an of axis insertion of the electrically driven hydraulic pump into the housing.

66. The electro-hydraulic actuator of claim 65, further comprising a hydraulically driven piston assembly operatively coupled to the housing.

67. The electro-hydraulic actuator of claim 66, wherein the housing is configured to fluidly couple the electrically driven hydraulic pump and the hydraulically driven piston assembly.

68. The electro-hydraulic actuator of any one of claims 65-67, wherein one or both of the first and second at least partially continuous annular grooves are continuous.#14746377vlL0710.70106WQ00- 61 -69. The electro-hydraulic actuator of any one of claims 65-68, wherein the first at least partially continuous annular groove is formed in the electrically driven hydraulic pump.

70. The electro-hydraulic actuator of any one of claims 65-68, wherein the first at least partially continuous annular groove is formed in a stator housing of the electrically driven hydraulic pump.

71. The electro-hydraulic actuator of any one of claims 65-70, wherein the second at least partially continuous annular groove is formed in the first portion of the housing.

72. The electro-hydraulic actuator of any one of claims 65-71, wherein the snap ring is disposed between an exterior surface of the electrically driven hydraulic pump and an interior surface of the first portion of the housing.

73. The electro-hydraulic actuator of any one of claims 65-72, wherein an internal volume formed between the housing and the electrically driven hydraulic pump is configured to be pressurized, and wherein when pressure is applied to the internal volume the first housing portion is biased towards a predetermined locked configuration, and the snap ring biases the housing and the electrically driven hydraulic pump towards the predetermined locked configuration.

74. The electro-hydraulic actuator of any one of claims 65-73, further comprising one or more biasing elements configured to bias the snap ring towards a locked configuration.

75. The electro-hydraulic actuator of claim 74, wherein the one or more biasing elements comprise a plurality of resilient fingers configured to contact the snap ring and bias the snap ring to the locked configuration.

76. The electro-hydraulic actuator of claim 75, wherein the plurality of flexible fingers is configured to contact a surface of the snap ring and bias the snap ring in an outward radial direction.#14746377vlL0710.70106WQ00- 62 -77. The electro-hydraulic actuator of any one of claims 65-76, further comprising at least one seal positioned between the first portion of the housing and the electrically driven hydraulic pump.

78. The electro-hydraulic actuator of any one of claims 65-77, wherein the first portion of the housing is a manifold.

79. The electro-hydraulic actuator of any one of claims 65-77, wherein the housing is at least a part of an integrally formed manifold.

80. The electro-hydraulic actuator of any one of claims 65-77 wherein the first portion of the housing is operatively coupled to a manifold.

81. A method for assembling an electro -hydraulic actuator, the method comprising:moving one or both of a first portion of a housing and an electrically driven hydraulic pump along an axis of insertion to assemble the first portion of the housing and the electrically driven hydraulic pump;camming a snap ring into one of a first at least partially continuous annular groove associated with the electrically driven hydraulic pump and a second at least partially continuous annular groove associated with the first portion of the housing during assembly of the first housing portion and the electrically driven hydraulic pump; andmoving the first housing portion, the electrically driven hydraulic pump, and the snap ring to a locked configuration, wherein the snap ring is disposed between and captured within axially overlapping portions of the first at least partially continuous annular groove and the second at least partially continuous annular groove to prevent relative movement of the housing and the electrically driven hydraulic pump along the axis of insertion.

82. The method of claim 81, further comprising pressurizing an interior volume of the electro-hydraulic actuator, wherein pressurizing the interior volume biases the housing towards a predetermined locked configuration relative to the snap ring and the electrically driven hydraulic pump.#14746377vlL0710.70106WQ00- 63 -83. The method of any one of claims 81-82, further comprising retaining the snap ring between an exterior surface of the electrically driven hydraulic pump and an interior surface of the first housing portion.

84. The method of any one of claims 81-83, further comprising aligning the snap ring with the controller housing receptacle using one or more tabs.

85. The method of any one of claims 81-84, further comprising biasing the snap ring towards a locked configuration.

86. The method of claim 85, wherein biasing the snap ring towards a locked configuration includes biasing the snap ring with a plurality of resilient fingers towards the locked configuration.

87. The method of any one of claims 81-86, further comprising forming a seal between the first portion of the housing and the electrically driven hydraulic pump.

88. The method of any one of claims 81-87, wherein moving one or both of the electrically driven hydraulic pump and the first housing portion along the axis of insertion to assemble the controller housing and the first housing portion includes inserting the electrically driven hydraulic pump into the first portion of the housing.

89. The method of any one of claims 81-88, wherein camming the snap ring includes flexing the snap ring radially inward during assembly of the first portion of the housing with the electrically driven hydraulic pump.

90. The method of any one of claims 81-89, wherein moving the first housing portion, the electrically driven hydraulic pump, and the snap ring to the locked configuration hydraulically couples the electrically driven hydraulic pump to a hydraulically driven piston assembly via the first portion of the housing.#14746377vlL0710.70106WQ00- 64 - 91. The method of claim 90, wherein the first portion of the housing is a manifold.

92. The method of claim 90, wherein the housing is at least a part of an integrally formed manifold.

93. The method of claim 90, wherein the first portion of the housing is operatively coupled to a manifold.

94. An electrically driven hydraulic pump comprising:an electrical unit that includes:a controller housing that includes:one or more circuit boards, at least one processor, and a position sensor;a stator housing that includes:a stator rigidly held within the stator housing with at least one pin connection protruding from the stator housing,a rotor shaft having a first rotor shaft end portion and a second rotor shaft end portion, wherein a target magnet with a north-south axis is positioned substantially perpendicular to an axis of rotation of the rotor shaft and located at the first rotor shaft end portion, a first bearing configured to radially support the first rotor shaft end portion,a second bearing configured to radially support the second rotor shaft end portion, anda support plate configured to support the second bearing;at least one tab and at least one corresponding groove; wherein the at least one tab is configured and positioned to engage the at least one groove and:secure the stator housing axially and rotationally relative to the controller housing when the stator housing is inserted into the controller housing during assembly,place the at least one pin connection in contact with a receiving electrical contact on the at least one circuit board, and#14746377vlL0710.70106WQ00- 65 - align the target magnet with the position sensor.

95. The electrically driven hydraulic pump of claim 94, further comprising:a hydraulic module including:a driveshaft including a first driveshaft end portion and a second driveshaft end portion; anda third bearing configured to radially support the second driveshaft end portion, wherein the first driveshaft end portion is operatively torsionally coupled to the second rotor shaft end portion and wherein the first driveshaft end portion is radially supported by the second end portion of the rotor shaft.

96. The electrically driven hydraulic pump of any one of claims 94-95, wherein the support plate includes one or more blind ports of the hydraulic module formed therein.

97. The electrically driven hydraulic pump of any one of claims 94-96, wherein the hydraulic module is a gerotor.

98. The electrically driven hydraulic pump of any one of claims 94-97, wherein the second end portion of the rotor shaft includes a keyed portion, and wherein the keyed portion is configured to torsionally interlock with and radially support a corresponding keyed portion of the first driveshaft end portion.

99. The electrically driven hydraulic pump of any one of claims 94-98, wherein the first driveshaft end portion is configured to be at least partially received within the second rotor shaft end portion.

100. The electrically driven hydraulic pump of any one of claims 94-99, wherein the support plate is configured to form a cap of the hydraulic module.

101. The electrically driven hydraulic pump of any one of claims 94-100, further comprising a pressure sensor configured to sense a pressure associated with the electrically driven hydraulic pump.#14746377vlL0710.70106WQ00- 66 -102. An electro-hydraulic actuator comprising:a body including an internal volume;a piston slidably received in the internal volume of the body, wherein the piston divides the internal volume into a first volume and a second volume; andthe electrically driven hydraulic pump of any one of claims 94-101, wherein a first port of the electrically driven hydraulic pump is in fluid communication with the first volume and a second port of the electrically driven hydraulic pump is in fluid communication with the second volume.#14746377vl

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