Integrated electro-hydraulic actuator

Abstract

An exemplary electro-hydraulic actuator includes: a housing; a hydraulic cylinder actuator disposed within the housing, including a cylinder and a piston, where the piston divides an internal space of the cylinder into a first chamber and a second chamber, and the hydraulic cylinder actuator is unbalanced; an accumulator disposed within the housing, including an annular fluid chamber surrounding a cylinder of the hydraulic cylinder actuator, where the accumulator is configured to provide a pressurized fluid flow or to receive an excess fluid flow, the excess fluid flow including a difference between a first fluid flow rate and a second fluid flow rate; and an assembly disposed within the housing, comprising: (i) a pump configured as a flow source; and (ii) a motor configured to drive the pump to provide fluid flow to the first or second chamber of the hydraulic cylinder actuator to drive the piston.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 493,002, filed March 30, 2023, the entire contents of which are incorporated herein by reference as if fully set forth in this specification. Background Technology

[0003] Operating machines such as hydraulic excavators, wheel loaders, loading shovels, backhoes, mining equipment, and industrial machinery may have one or more actuators, such as lifting and / or tilting booms, booms, buckets, steering and tipping functions (devices), and traveling means. Typically, in such machines, a prime mover drives a hydraulic pump to supply fluid to the actuators. Opening or closing a center valve controls the flow of fluid to the actuators. These valves are characterized by significant power losses due to throttling. Furthermore, such conventional systems may involve supplying a constant flow from the pump, regardless of the number of actuators used. Therefore, such systems are relatively inefficient.

[0004] Therefore, hydraulic systems that improve the efficiency of operating machines are desired. With the increasing trend of electrification due to emission regulations, some hydraulic systems have been configured to include distributed or decentralized electro-hydraulic actuators (EHAs), which reduce throttling losses and are capable of energy recovery from overloads.

[0005] Example EHAs may include an electro-hydraulic power unit with a motor to drive a pump to provide fluid flow to an actuator, such as a linear hydraulic actuator cylinder or a hydraulic motor. Typically, standard components are arranged and connected together to form the EHA. For example, the motor is coupled to the pump such that the motor is axially spaced from the pump and connected to the pump via a shaft. For example, the motor and pump may be positioned next to the hydraulic cylinder.

[0006] In addition, a reservoir can be placed next to the pump. Separate valve modules or manifolds are also connected to the pump, reservoir, and hydraulic cylinder via fluid lines (such as pipes, hoses, etc.).

[0007] While this structure involves the use of standard components, it may not be suitable for many applications such as construction equipment (e.g., excavators, wheel loaders, etc.) that are subjected to impacts, rocks, debris, etc. Especially in environments where rocks and debris may continuously impact the components of the EHA, this structure may not provide adequate structural integrity. Furthermore, due to its larger footprint, this structure has a lower power volume density. Additionally, the multiple fluid couplings connecting the various components present potential leakage points, thus reducing system reliability.

[0008] Therefore, to improve the performance and reliability of the EHA, it is desirable to integrate the EHA components into a compact (self-contained) structure that requires no or very few external connections. This paper presents its disclosure based on these and other considerations. Summary of the Invention

[0009] This disclosure describes implementation methods related to integrated electro-hydraulic actuators.

[0010] Specifically, this disclosure describes an electro-hydraulic actuator in which an accumulator is integrated with a hydraulic cylinder actuator, such that a fluid chamber of the accumulator is formed within a housing of the electro-hydraulic actuator and surrounds a cylinder of the hydraulic cylinder actuator disposed within the housing.

[0011] The present invention also describes a method for assembling an electro-hydraulic actuator.

[0012] The above overview is for illustrative purposes only and is not intended to limit the invention in any way. Other aspects, embodiments, and features, besides the exemplary aspects, implementations, and features described above, will become apparent from the accompanying drawings and the following detailed description. Attached Figure Description

[0013] The appended claims set forth novel features of the illustrative embodiments. However, the illustrative embodiments, their preferred uses, further objects, and descriptions will be better understood in conjunction with the accompanying drawings and the following detailed description of the disclosure.

[0014] Figure 1 A schematic diagram of a hydraulic system according to an example embodiment is shown.

[0015] Figure 2 A perspective view of an electro-hydraulic actuator according to an example embodiment is shown, which integrates an electro-hydraulic power unit, an accumulator, a valve, and a hydraulic actuator cylinder in a single assembly.

[0016] Figure 3 An example embodiment is shown. Figure 2 A cross-sectional side view of an electro-hydraulic actuator.

[0017] Figure 4 An example embodiment is shown. Figure 2 A perspective cross-sectional view of an electro-hydraulic actuator.

[0018] Figure 5 A perspective view of a first housing portion and a motor and pump assembly disposed therein, according to an example embodiment, is shown.

[0019] Figure 6A cross-sectional side view of a first housing portion and components disposed therein, according to an example embodiment, is shown.

[0020] Figure 7 An example embodiment is shown. Figure 2 A perspective cross-sectional view of the electro-hydraulic actuator, showing the connector module mounted to the manifold.

[0021] Figure 8 An example embodiment is shown. Figure 7 Rear view of the connector module.

[0022] Figure 9 An example embodiment is shown. Figure 2 A perspective cross-sectional view of the electro-hydraulic actuator, showing the manifold.

[0023] Figure 10 An example embodiment is shown. Figure 9 Rear view of the manifold.

[0024] Figure 11 An example embodiment is shown. Figure 9 Side view of the manifold.

[0025] Figure 12 An example embodiment is shown. Figure 9 A front view of the manifold.

[0026] Figure 13 Assembly according to the example embodiment Figure 2-4 A flowchart of a method for using an electro-hydraulic actuator. Detailed Implementation

[0027] Taking excavators as an example, hydraulic machines can use multiple hydraulic actuators to accomplish various tasks. Many electric hybrid and battery-powered machines use multiple hydraulic cylinders and motors to perform various tasks. Improving machine efficiency is desirable, enabling a reduction in the size of hybrid internal combustion engines and / or batteries while lowering battery thermal management costs.

[0028] Example system approaches to improve efficiency include on-demand, closed-circuit systems, which have dedicated hydrostatic pumps and motors for each actuator in the machine. This approach improves efficiency by addressing valve metering, pressure excess, and standby losses common in conventional systems, while also enabling electrical energy recovery from the hydraulic fluid.

[0029] The combination of a hydrostatic pump and an electric motor can be referred to as an electro-hydraulic power unit. As described in more detail below, when such an electro-hydraulic power unit is used to operate unbalanced actuators (e.g., hydraulic cylinder actuators comprising chambers with different volumes), a variable-capacity reservoir (e.g., an accumulator) can serve as a fluid source, providing pressurized fluid to the unbalanced actuator. Thus, such a reservoir can compensate for the difference in fluid velocity / flow rate between the fluid supplied to the actuator and the fluid discharged from the actuator. The reservoir can also absorb excess flow when the fluid velocity / flow rate discharged from the actuator is greater than the fluid velocity / flow rate supplied to the actuator.

[0030] Furthermore, various valves can be used for wiring between the reservoir, electro-hydraulic power unit, and hydraulic actuator. Therefore, an electro-hydraulic actuator can include hydraulic cylinder actuators, reservoirs (e.g., accumulators), valve modules or manifolds, and various connections between these components.

[0031] This document discloses a component that integrates parts of an electro-hydraulic actuator to improve the power volume density and reliability of the system. As an example, the disclosed component includes a housing in which a compact electro-hydraulic power unit (e.g., a motor and pump) is housed. A valve module or manifold integrating various valves of the electro-hydraulic actuator is also housed within the housing. In one example, a connector module for guiding fluid between the parts of the electro-hydraulic actuator is also integrated within the housing. A variable-capacity reservoir (e.g., an accumulator) is disposed around a hydraulic cylinder such that the reservoir surrounds at least a portion of the hydraulic cylinder. This configuration provides a compact, efficient, and reliable component.

[0032] Figure 1 A schematic diagram of a hydraulic system 100 using an accumulator 102 as a source of pressurized fluid, according to an example embodiment, is shown. The hydraulic system 100 includes a hydraulic cylinder actuator 104 having a cylinder 106 and a piston 108 slidably housed within the cylinder 106 and configured to move therein in a linear direction.

[0033] The piston 108 includes a piston head 110 and a rod 112 extending from the piston head 110 along the central longitudinal axis of the cylinder 106. The rod 112 can be coupled to a load, which represents, for example, a machine action (e.g., boom, arm, or bucket) and the force applied thereto. The piston head 110 divides the internal space of the cylinder 106 into a first chamber 116 and a second chamber 118.

[0034] The first chamber 116 may be referred to as the head-side chamber because the fluid therein interacts with the piston head 110; the second chamber 118 may be referred to as the rod-side chamber because the rod 112 is partially located therein. Fluid can flow into and out of the first chamber 116 through the working port 117, and can also flow into and out of the second chamber 118 through the working port 119.

[0035] Piston head 110 can have a diameter of D H The piston rod 112 can have a diameter of D. R Therefore, the fluid in the first chamber 116 interacts with the cross-sectional area of ​​the piston head 110, which can be called the piston head area and is equal to... On the other hand, the fluid in the second chamber 118 interacts with the annular surface area of ​​the piston 108, which can be referred to as the piston annular area.

[0036] Area A annular Smaller than piston head area A H Therefore, when the piston 108 extends within the cylinder 106 (e.g., in...), Figure 1 Move to the right (from center) or withdraw (e.g., in Figure 1 When the fluid moves from center to left, the amount Q of fluid entering or exiting the first chamber 116 is... A The amount Q of fluid flow that is greater than the amount of fluid discharged from or entering the second chamber 118 a .

[0037] Specifically, if piston 108 moves at a specific speed V, then Q A =A H V is greater than Q a =A Annular The difference in flow can be determined as Q. A -Q a =A R V, where A R It is the cross-sectional area of ​​rod 112 and equal to With this configuration, the hydraulic cylinder actuator 104 can be called an unbalanced actuator because the fluid velocity / flow rate flowing into / out of the first chamber 116 is not equal to the fluid velocity / flow rate flowing into / out of the second chamber 118.

[0038] The hydraulic system 100 includes an electro-hydraulic power unit 120, which contains a motor that drives a pump. The electro-hydraulic power unit 120 is configured to control the speed and direction of hydraulic fluid flow into and out of the hydraulic cylinder actuator 104. This control is achieved by controlling the speed and direction of the motor and pump, which are configured as bidirectional fluid flow sources.

[0039] The electro-hydraulic power unit 120 has a first pump port 122 connected to a first chamber 116 of the hydraulic cylinder actuator 104 via a first fluid line 124, and a second pump port 126 connected to a second chamber 118 of the hydraulic cylinder actuator 104 via a second fluid line 128. The term "fluid line" is used herein to refer to one or more fluid passages, pipes, etc., providing explicit connectivity.

[0040] The first pump port 122 and the second pump port 126 are configured as inlet and outlet ports, respectively, depending on the rotation direction of the motor rotor driving the pump. When the motor rotor rotates in the first rotation direction, the pump draws fluid from the first pump port 122 (the inlet port in this example) and discharges the fluid to the second pump port 126 (the outlet port in this example). Conversely, when the rotor rotates in the second rotation direction, the pump draws fluid from the second pump port 126 (the inlet port in this example) and discharges the fluid to the first pump port 122 (the outlet port in this example).

[0041] Furthermore, as described in more detail below, the electro-hydraulic power unit 120 is configured to operate in both a pumping mode and a motor mode. In the pumping mode, the motor drives the pump to supply fluid, thereby driving the piston 108 to overcome resistance loads.

[0042] In motor mode (e.g., regenerative mode), the hydraulic cylinder actuator 104 bears an auxiliary load (e.g., the direction of the force acting on piston 108 is the same as the direction of movement of piston 108). Therefore, in motor mode, the fluid driven pump discharged from and returned to the electro-hydraulic power unit 120 from the hydraulic cylinder actuator 104, which in turn drives the motor. In this case, the motor acts as a generator, where the fluid energy received at the electro-hydraulic power unit 120 is converted into electrical energy by the motor. The electrical energy generated in this mode can be stored, for example, in a battery. Therefore, the motor can generally be referred to as a motor configured to operate as both a motor and a generator.

[0043] like Figure 1 As shown, the pump and hydraulic cylinder actuator 104 of the electro-hydraulic power unit 120 are configured in a closed loop, i.e., a closed-loop hydraulic circuit. As used herein, the term "closed loop" refers to a circuit in which fluid circulates between the pump and the hydraulic cylinder actuator 104. Specifically, in the hydraulic system 100, the pump supplies fluid to the working port 117 via a first pump port 122 or to the working port 119 via a second pump port 126, and fluid discharged from the other working port returns to the corresponding port of the pump. Thus, fluid circulates between the pump and the hydraulic cylinder actuator 104.

[0044] In one example, the pump may be a fixed displacement pump, and the amount of fluid flow provided by the pump is controlled by the speed of the motor (i.e., the rotational speed of the rotor of the motor coupled to the pump). For example, the pump may be configured to have a specific pump displacement P. D The displacement determines the amount of fluid produced or supplied by the pump, such as cubic inches per revolution (in). 3 / rev). The motor can operate at a commanded speed (which has units of revolutions per minute (RPM)). Therefore, multiply the motor speed by P. DThe fluid flow rate / flow rate Q supplied by the pump to the hydraulic cylinder actuator 104 can be determined (which is in cubic inches per minute). 3 ( / min)

[0045] The flow rate / flow velocity Q, in turn, determines the linear velocity of piston 108. For example, if the motor-driven pump is in the first direction of rotation to supply fluid to the first chamber 116, piston 108 can achieve a velocity... Operation. On the other hand, if the motor-driven pump is in the second rotational direction to supply fluid to the second chamber 118, the piston 108 can operate at a speed withdraw.

[0046] As described above, the hydraulic cylinder actuator 104 is unbalanced, resulting in a greater amount of fluid flow supplied to or discharged from the first chamber 116 than to the second chamber 118. Consequently, the fluid flow rate at the first pump port 122 (to or out of the first chamber 116) is greater than the fluid flow rate at the second pump port 126 (to or out of the second chamber 118). This difference between the fluid flow rate supplied and received by the pump can lead to cavitation, causing the pump to malfunction.

[0047] The hydraulic system 100 includes a variable-capacity reservoir, such as an accumulator 102, configured to increase fluid flow rate or receive any excess flow to compensate for differences in fluid flow rate. The accumulator 102 may be configured to provide fluid flow within a specific pressure range, such as 0 to 15 bar. As a specific example, the accumulator 102 may provide fluid at a pressure level of 4-5 bar.

[0048] Accumulator 102 is configured to provide boosted flow or receive excess flow through boosted flow line 132. In one example, accumulator 102 may provide or receive fluid directly from boosted flow line 132. In another example, accumulator 102 provides boosted flow to or receives excess flow from boosted flow line 132 via electro-hydraulic power unit 120. Specifically, as described in more detail below, the motor and pump of electro-hydraulic power unit 120 may be integrated into an assembly having an internal chamber through which boosted flow or excess flow flows to or out of accumulator 102 to cool the motor, rather than using a separate cooling configuration.

[0049] In one example, accumulator 102 is configured as a pressure storage container in which incompressible hydraulic fluid is held under pressure applied by an external source of mechanical energy. The external source can be an engine, a spring, a raised weight, or compressed gas. For example, accumulator 102 can have a cylindrical chamber with a piston inside. The piston can be spring-loaded or pressurized by gas located on one side of the piston.

[0050] When fluid enters the accumulator 102 (which operates as a sealed container with a fixed volume), the fluid volume within the accumulator 102 increases, and the fluid pressure also increases due to the spring or gas pressure acting on the other side of the piston. In this way, the accumulator 102 can supply pressurized fluid to the booster flow line 132.

[0051] Other types of accumulators can be used. For example, accumulator 102 can be a bladder accumulator. Such an accumulator may include a bladder filled with nitrogen and assembled in a welded or forged steel pressure vessel. The bladder is made of an elastic material (e.g., rubber). The gas pre-charge pressure can be adjusted by a gas inlet / outlet valve on top of the bladder accumulator. When the pressure level of the hydraulic fluid within the accumulator decreases, the compressed gas in the bladder expands and pushes the stored fluid into the hydraulic circuit. Conversely, when hydraulic fluid is supplied to the accumulator, the hydraulic fluid compresses the bladder, thereby increasing the pressure level of the fluid within the accumulator. In other examples, accumulator 102 can be a diaphragm accumulator or a spring accumulator, wherein a diaphragm or spring replaces the compressed gas.

[0052] The booster flow line 132 is connected to a reverse shuttle valve 130, which is configured to fluidly couple chambers 116 and 118 of cylinder 106 to the booster flow line 132 in response to a pressure difference across the pump (i.e., the pressure difference between the first fluid line 124 and the second fluid line 128). In one example, the reverse shuttle valve 130 may be configured as a pilot-operated three-position shuttle valve having a shuttle element (e.g., a lift valve or slide valve) whose position is determined by the pressure difference across the pump.

[0053] The reverse shuttle valve 130 may have a first pilot port 134 fluidly coupled to a first fluid line 124 and a second pilot port 136 fluidly coupled to a second fluid line 128. The reverse shuttle valve 130 also has a booster port 138 fluidly coupled to a booster flow line 132. The reverse shuttle valve 130 is operated by the pressure difference between the fluid lines 124 and 128 such that: (i) when the pressure in the first fluid line 124 exceeds the pressure level in the second fluid line 128, the second fluid line 128 is connected to the booster flow line 132, or (ii) when the pressure in the second fluid line 128 exceeds the pressure level in the first fluid line 124, the first fluid line 124 is connected to the booster flow line 132.

[0054] For example, if the pump is driven by an electric motor to supply fluid to the first fluid line 124, causing the piston 108 to extend, the pressure difference across the pump will displace the shuttle element of the reverse shuttle valve 130, thereby connecting the booster port 138 to the second pilot port 136, thus fluidly coupling the second fluid line 128 to the booster flow line 132, while blocking flow from the first fluid line 124 to the booster flow line 132. In this way, the reverse shuttle valve 130 provides a fluid flow path from the booster flow line 132 to the second pump port 126 to compensate for the difference between the fluid velocity / rate supplied to the first chamber 116 and the fluid velocity / rate returning from the second chamber 118 through the second fluid line 128.

[0055] Conversely, when the pump is driven in the opposite direction to retract piston 108, the pressure difference across the pump displaces the shuttle element of the reverse shuttle valve 130 to connect the first pilot port 134 to the booster port 138, thereby fluidly coupling the first fluid line 124 to the booster flow line 132 while blocking flow from the second fluid line 128 to the booster flow line 132. In this way, the reverse shuttle valve 130 provides a fluid flow path for excess fluid flow returning from the first chamber 116 through the first fluid line 124 to the booster flow line. The different operating modes of the hydraulic system 100 and the reverse shuttle valve 130 are described below.

[0056] The term "reverse" refers to the reverse shuttle valve 130 because it differs from a conventional shuttle valve. A conventional shuttle valve may have a first inlet, a second inlet, and an outlet. In such a conventional shuttle valve, the valve spool moves freely within it such that when pressure from the fluid is applied through a particular inlet, it pushes the spool towards the opposite inlet. This movement blocks the opposite inlet while allowing fluid to flow from the particular inlet to the outlet. In this way, two different fluid sources can supply pressurized fluid to the outlet without backflow from one source to another. The reverse shuttle valve 130 does not have a designated outlet port; instead, it provides fluid flow from a pressurized port 138 to a second pilot port 136 or from a first pilot port 134 to a pressurized port 138.

[0057] In the example configuration described above, the reverse shuttle valve 130 is a pilot-operated valve, wherein the shuttle element moves in response to a pressure differential between fluid lines 124, 128. In other examples, the reverse shuttle valve 130 may be electrically actuated, such that an electronic controller of the hydraulic system 100 can provide an electrical signal that moves the shuttle element based on a sensed pressure level in the fluid lines 124, 128.

[0058] In one example, the hydraulic system 100 also includes a filter 140 for filtering the fluid to remove any contaminants. In this example, a check valve 142 may be used to prevent backflow from the second fluid line 128 to the filter 140 or the booster flow line 132.

[0059] In one example, the hydraulic system also includes a shuttle valve 144, a metering valve 146, and a pressure relief valve 148. The metering valve 146 is configured as a throttle valve to meter or throttle the fluid flow discharged from the hydraulic cylinder actuator 104 to achieve a low speed for the piston 108, as described below. For example, the metering valve 146 may be a proportional valve, which is electronically actuated by a solenoid valve 150. Electrical command signals from the controller of the hydraulic system 100 to the solenoid valve 150 control the fluid flow through the metering valve 146.

[0060] The shuttle valve 144 has a first inlet port 152 fluidly coupled to a first fluid line 124 and a first chamber 116, and a second inlet port 154 fluidly coupled to a second fluid line 128 and a second chamber 118. The shuttle valve 144 also has an outlet port 156 fluidly coupled to an inlet 158 ​​of a metering valve 146. The outlet 160 of the metering valve 146 is fluidly coupled to a booster flow line 132.

[0061] When the fluid pressure level in the first chamber 116 is higher than the fluid pressure level in the second chamber 118, the shuttle valve 144 provides a fluid path from the first inlet port 152 (and the first chamber 116) to the outlet port 156. Conversely, when the fluid pressure level in the second chamber 118 is higher than the fluid pressure level in the first chamber 116, the shuttle valve 144 provides a fluid path from the second inlet port 154 (and the second chamber 118) to the outlet port 156.

[0062] In certain situations, the hydraulic cylinder actuator 104 may be subjected to large forces, which could cause overpressure in either of the chambers 116 or 118. To protect the hydraulic cylinder actuator 104 from the possibility of overpressure, the hydraulic system 100 includes a pressure relief valve 148.

[0063] Pressure relief valve 148 is configured to protect chambers 116 and 118. Fluid with a higher pressure level between chambers 116 and 118 flows to pressure relief valve 148 through shuttle valve 144. If the pressure level exceeds a threshold (e.g., 300 bar or 4350 psi), pressure relief valve 148 opens when metering valve 146 is closed (not activated), releasing this high-pressure fluid to booster flow line 132.

[0064] Other types of valves can be added to the hydraulic system 100. For example, a load-holding valve can be added. Such load-holding valves can be configured as pilot-operated check valves, balance valves, electrically controlled on / off valves, etc.

[0065] The hydraulic system 100 is configured to operate in at least four operating modes. The first operating mode involves extending the piston 108 while it is subjected to a resistance load (e.g., in...). Figure 1(The piston 108 moves to the right). The term "resistance" means that the direction of the force exerted on the piston 108 by the load is opposite to the direction of movement of the piston 108. The second operating mode involves extending the piston 108 while it is subjected to an auxiliary load. The term "auxiliary" means that the direction of the force exerted on the piston 108 by the load is the same as the direction of movement of the piston 108. This may occur, for example, if the movement of the piston 108 is assisted by gravity.

[0066] In the first and second operating modes, the accumulator 102 is configured to provide a pressurized flow to the pressurized flow line 132 via a motor. In other words, the accumulator 102 operates in a discharge mode, in which fluid is discharged from the accumulator 102.

[0067] The third operating mode involves retracting piston 108 when it is subjected to a resistance load (e.g., in...). Figure 1 (The piston 108 moves to the left). The fourth operating mode involves retracting the piston 108 when it is under an auxiliary load. In the third and fourth operating modes, the accumulator 102 is configured to receive excess flow from the booster flow line 132 via a motor. In other words, the accumulator 102 operates in a charging mode, where excess fluid is used to charge the accumulator 102.

[0068] Specifically, in order to extend piston 108 under resistance load (first operating mode), the controller of hydraulic system 100 can send a command signal to the power electronics module to operate the motor and drive the pump of electro-hydraulic power unit 120 in a first rotational direction. Fluid velocity / flow rate Q A Therefore, fluid is supplied from the first pump port 122 through the first fluid line 124 to the first chamber 116 to extend the piston 108. When the piston 108 extends, fluid is supplied at a fluid flow rate Q. a It is discharged from the second chamber 118 to the second fluid line 128.

[0069] Meanwhile, the accumulator 102 can provide supplementary or boosted flow Q. acc The pressure flow is directed to the booster flow line 132. Specifically, the high-pressure fluid in the first fluid line 124 causes the reverse shuttle valve 130 to switch to a state where it couples the fluid from the booster flow line 132 to the second fluid line 128. Therefore, the reverse shuttle valve 130 operates in a state where the second pilot port 136 is fluidly coupled to the booster port 138, and thus the boosted flow provided by the accumulator 102 merges with the fluid discharged from the second chamber 118 in the second fluid line 128. The supplemental or booster flow Q provided by the accumulator 102... acc It was identified as Q acc =A R V, where A RV is the cross-sectional area of ​​rod 112, and V is the velocity of piston 108, as described above. The combined flow rate / flow rate Q... A =Q a +Q acc It flows from the second chamber 118 and the accumulator 102, and then to the second pump port 126.

[0070] Therefore, the amount of flow velocity / rate received at the second pump port 126 is equal to the amount of flow velocity / rate supplied by the pump to the first chamber 116 through the first pump port 122 and the first fluid line 124. It is worth noting that the fluid returning from the second chamber 118 to the second pump port 126 through the second fluid line 128 has a low pressure level, and therefore, the boosted flow Q provided by the accumulator 102... acc It can be provided at a low pressure level that matches the low pressure level of the flow returning to the second pump port 126. For example, the booster flow can have a pressure level in the range of 0-15 bar, which is compared to a high pressure level of, for example, 300 bar that can be provided by the pump to the first chamber 116, so that the piston 108 can extend over the resistance load.

[0071] In this mode, the electro-hydraulic power unit 120 (i.e., the motor and pump) provides hydraulic power P to the hydraulic cylinder actuator 104. EHU This allows the piston 108 to move against the resistance load at a specific speed.

[0072] The second operating mode involves extending piston 108 while subjected to an auxiliary load (extending piston 108 at a specific speed while the auxiliary load acts in the same direction). In this mode, the fluid in the first fluid line 124 is a low-pressure fluid, while the fluid discharged from the second chamber 118 to the second fluid line 128 can be a high-pressure fluid. The pump operates at the second pump port 126 at a flow rate Q. a It receives the fluid discharged from the second chamber 118, and thus at the same flow rate Q. a Fluid is supplied to the first fluid line 124. In this case, the high-pressure fluid received at the second pump port 126 drives the pump, which in turn drives the motor in regenerative mode, thereby generating electricity P. EHU Instead of consuming electricity.

[0073] Furthermore, the high-pressure fluid in the second fluid line 128 causes the reverse shuttle valve 130 to switch to a state where it couples the booster flow line 132 to the first fluid line 124. Specifically, the reverse shuttle valve 130 operates in a state where the first pilot port 134 is fluidly coupled to the booster port 138, and thus the booster flow Q provided by the accumulator 102... accThe fluid flows through the booster flow line 132 to the booster port 138, and then to the first pilot port 134, to meet the fluid flow Q supplied by the pump in the first fluid line 124. a Convergence. Combined fluid flow Q A =Q a +Q acc The first chamber 116 is provided to the hydraulic cylinder actuator 104.

[0074] It is worth noting that the fluid supplied by the pump to the first fluid line 124 has a low pressure level. Therefore, the boosted flow Q provided by the accumulator 102 acc It can be provided at a low pressure level (e.g., between 0 and 15 bar), which matches the low pressure level of the flow provided via the first pump port 122.

[0075] The third operating mode involves retracting piston 108 under resistance load conditions. To retract piston 108 (e.g., in...) Figure 1 As piston 108 moves to the left, the controller of hydraulic system 100 can send a command signal to the power electronics module to operate the motor and drive the pump in a second rotational direction (opposite to the first rotational direction associated with piston 108 extension). The fluid velocity / flow rate Q of the high-pressure fluid... a Therefore, fluid is supplied from the second pump port 126 to the second chamber 118 through the second fluid line 128 to retract the piston 108. When the piston 108 retracts, fluid flows at a fluid velocity / rate Q. A It is discharged from the first chamber 116 to the first fluid line 124.

[0076] Since the pump provides a fluid flow rate Qa at the second pump port 126, the pump receives the same amount of fluid flow rate Qa at the first pump port 122. A and Q a The flow difference (excess flow) branches to the first pilot port 134 of the reverse shuttle valve 130 and is used as the flow rate / flow velocity Q. acc It is supplied to the accumulator 102 to charge the accumulator 102.

[0077] Specifically, the high-pressure fluid in the second fluid line 128 causes the reverse shuttle valve 130 to switch to a state where it couples the fluid in the booster flow line 132 to the first fluid line 124. Specifically, the reverse shuttle valve 130 operates in a state where the fluid in the first pilot port 134 is fluidly coupled to the booster port 138, and therefore differential pressure or excessive flow Q... acc =Q A -Q aThe fluid flows from the first oil passage 124 to the first pilot port 134, then to the booster port 138, then to the booster flow line 132 (through the motor and pump housing), and finally to the accumulator 102 for charging. In this mode, the electro-hydraulic power unit 120 (i.e., the motor and pump) provides hydraulic power P to the hydraulic cylinder actuator 104. EHU This causes piston 108 to overcome the resistance load and retract at a specific speed.

[0078] The fourth operating mode involves retracting piston 108 when subjected to an auxiliary load. In this operating mode, piston 108 can retract at a specific speed when the auxiliary load acts in the same direction.

[0079] When piston 108 retracts with the aid of a load, the pump supplies low-pressure fluid to the second fluid line 128 through the second pump port 126, while the fluid discharged from the first chamber 116 to the first fluid line 124 can be a high-pressure fluid. The pump operates at a flow rate Q at the first pump port 122. A Receives fluid discharged from the first chamber 116, and thus at the same flow rate Q. A Fluid is supplied to the first fluid line 124. In this case, the high-pressure fluid received through the first fluid line 124 drives a pump, which in turn drives a motor in regenerative mode, thereby generating electricity P. EHU Instead of consuming electricity.

[0080] When the pump provides fluid flow rate / flow rate Q A Upon reaching the second fluid line 128, the second chamber 118 receives the fluid velocity / rate Q. a Differential flow or excessive flow Q A -Q a Provided as accumulator flow Q acc This is to charge the storage battery 102.

[0081] Specifically, the high-pressure fluid in the first fluid line 124 causes the reverse shuttle valve 130 to switch to a state where it couples the fluid in the booster flow line 132 to the second fluid line 128. Specifically, the reverse shuttle valve 130 operates in a state where the fluid in the second pilot port 136 is fluidly coupled to the booster port 138, thus excess flow Q... acc =Q A -Q a The fluid flows from the second fluid line 128 to the second pilot port 136, to the booster port 138, then to the booster flow line 132 (through the motor and pump housing or casing), and then to the accumulator 102 to charge it.

[0082] In the four modes described above, metering valve 146 may not be used (i.e., metering valve 146 remains closed in the inactive state). However, in some examples, it is desirable to operate metering valve 146 at a low speed (e.g., extend or retract piston 108), but the pump and motor may be configured to operate at a minimum speed, which may not be suitable for moving piston 108 at such a low speed. In these cases, metering valve 146 can be used to throttle the fluid to achieve a lower piston speed.

[0083] For example, if piston 108 needs to extend at a low speed to overcome resistance load, the motor can operate at a minimum speed. Metering valve 146 can then be activated to allow a portion Q of the fluid flowing through the first fluid line 124 to... t The flow passes through shuttle valve 144 to metering valve 146, then to booster flow line 132, and combines with accumulator flow Q. acc By controlling the opening of the metering valve 146 (e.g., by controlling the magnitude of the voltage or current supplied to the solenoid valve 150 of the metering valve 146), the metering valve 146 can be throttled to reduce the speed of the piston 108 to the desired speed.

[0084] To extend piston 108 under auxiliary load, the motor can be stopped (i.e., the motor and pump are not commanded to provide flow). Fluid discharged at high pressure from second chamber 118 flows through second fluid line 128, and then a portion of that flow Q t The fluid is supplied to metering valve 146 via shuttle valve 144, which throttles the flow to control the speed of piston 108. Fluid flow Q t Then combine the accumulator current Q acc The combined fluid flows through the reverse shuttle valve 130 to the first fluid line 124, and then to the first chamber 116. In this way, the pump does not supply fluid, and the metering valve 146 controls the speed of the piston 108.

[0085] However, if it is desired to increase the speed of piston 108 while subjected to auxiliary load, the motor can operate at its maximum speed to provide a large flow of fluid to the first chamber 116 and extend piston 108 at high speed.

[0086] To overcome the resistance load and retract the piston 108 at a low speed, the motor can operate at minimum speed. Therefore, the pump supplies fluid to the second fluid line 128, and a portion of that fluid, Q... t The fluid is supplied through shuttle valve 144, then through metering valve 146, which throttles the flow, before supplying it to booster line 132. Flow Q t It merges with a portion of the fluid discharged from the first chamber 116, which flows through the reverse shuttle valve 130 to the booster flow line 132, and the combined flow is Q. accIt is supplied to the accumulator for charging.

[0087] To retract piston 108 using an auxiliary load, the motor can be stopped (i.e., the motor and pump are not commanded to provide flow). Fluid flow Q is discharged from the first chamber 116 at high pressure. A The fluid flows through the first fluid line 124 and then through the shuttle valve 144 to the metering valve 146, where the metering valve 146 throttles the flow to control the speed of the piston 108. In this case, Q t =Q A And fluid flow Qt is supplied to the booster flow line 132. Flow Q t Part of Q acc Provided to the accumulator 102 as Q acc And another part Q a The fluid is supplied to the second fluid line 128 via the reverse shuttle valve 130, so as to be supplied to the second chamber 118.

[0088] However, if it is desired to increase the retraction speed of piston 108 under auxiliary load, the motor can operate at its maximum speed to provide a large fluid flow to the second chamber 118 and retract piston 108 at high speed.

[0089] The desired approach is to integrate the components of the hydraulic system 100 into a separate electro-hydraulic actuator (EHA) unit, where the hydraulic cylinder actuator 104, accumulator 102, various valves, and electro-hydraulic power unit 120 are integrated into a single unit or assembly to improve the power-to-volume ratio. This configuration can further eliminate the need for joints and hoses, thereby improving the reliability of the hydraulic system 100.

[0090] Figure 2 A perspective view of EHA 200 is shown, which integrates the electro-hydraulic power unit 120, accumulator 102, valves and hydraulic cylinder actuators 104 of hydraulic system 100 into a single assembly. Figure 3 A cross-sectional side view of the EHA 200 is shown, and Figure 4 A perspective cross-sectional view of the EHA 200 according to an example embodiment is shown. Figure 2-4 They were described together.

[0091] The EHA 200 has a housing 202, which includes a first housing portion 204 (e.g., a rear housing cover) and a second housing portion 206 (e.g., a front housing cover) coupled to the first housing portion 204. For example, the first housing portion 204 may be screwed into the second housing portion 206. The first housing portion 204 and the second housing portion 206 together serve for the housing 202, which defines a enclosure in which the electro-hydraulic power unit 120, valves of the hydraulic system 100, hydraulic cylinder actuators 104, and accumulator 102 are disposed.

[0092] The first housing portion 204 is configured to house or contain the electro-hydraulic power unit 120, which includes the motor and pump assembly 205 described below. The second housing portion 206 is configured to house or contain the hydraulic cylinder actuator 104, the accumulator 102, and the manifold 208 of the valves of the integrated hydraulic system 100.

[0093] For example, the hydraulic cylinder actuator 104 may include an end cap or gland 209, and the cylinder 106 of the hydraulic cylinder actuator 104 may be screwed to the gland 209 to mount the hydraulic cylinder actuator 104 within the second housing portion 206. The gland 209 may be generally annular and may have a seal on its inner circumferential surface such that the seal is arranged around the rod 112 of the piston 108 to seal the second chamber 118 and prevent fluid leakage into the environment of EHA 200. The cylinder 106 of the hydraulic cylinder actuator 104 is at least partially disposed within the second housing portion 206.

[0094] The EHA 200 may also include a connector module 210 that fluidly couples the electro-hydraulic power unit 120 to the manifold 208. For example... Figure 3-4 As shown, the connector module 210 is partially disposed within the first housing portion 204 and partially disposed within the second housing portion 206, and is located between the manifold 208 and the assembly 205.

[0095] exist Figure 2-4 In this embodiment, the second housing portion 206 operates as the housing or outer wall of the accumulator 102. The accumulator 102 has an annular fluid chamber 212 that surrounds or encloses the cylinder 106 of the hydraulic cylinder actuator 104, such that the annular fluid chamber 212 is radially interposed or formed between the inner surface of the second housing portion 206 and the outer surface of the cylinder 106. With this configuration, the hydraulic cylinder actuator 104 is fitted within the accumulator 102. In other words, the annular fluid chamber 212 is formed between the outer peripheral surface of the cylinder 106 and the inner peripheral surface of the second housing portion 206.

[0096] An annular fluid chamber 212 is configured to contain hydraulic fluid. The volume of the annular fluid chamber 212 can be determined and related to the dimensions of the piston 108 (e.g., D). H D R The configuration and stroke of piston 108 are related to the volume of pressurized fluid that needs to flow into or out of the first chamber 116, and thus determine the volume of the annular fluid chamber 212.

[0097] exist Figure 3-4In one embodiment, the accumulator 102 is configured as a piston-type accumulator, which includes an annular gas chamber 214 that also surrounds or encloses the cylinder 106 of the hydraulic cylinder actuator 104. The annular gas chamber 214 is configured to contain a gas (e.g., nitrogen) for the accumulator 102. An accumulator gas valve 215 can be used to precharge the annular gas chamber 214 with gas.

[0098] The annular gas chamber 214 is separated from and sealed to the annular fluid chamber 212 by the annular piston 216 of the accumulator 102. The annular piston 216 surrounds or encloses the cylinder 106 of the hydraulic cylinder actuator 104 and is slidably accommodated in the annular space formed between the second housing portion 206 and the cylinder 106. The annular piston 216 may have one or more seals disposed in annular grooves formed on its outer surface to seal the annular gas chamber 214 relative to the annular fluid chamber 212.

[0099] As shown in the figure, the annular gas chamber 214 is axially located between the annular piston 216 and the accumulator head 217. The accumulator head 217 may have external threads configured to engage with the internal threads of the second housing portion 206 to mount the second housing portion 206 to the accumulator head 217.

[0100] During the charging phase of the accumulator 102, when fluid is supplied to the annular fluid chamber 212, the annular piston 216 moves in the distal direction (e.g., Figure 3 (From center to left), thereby compressing the gas in the annular gas chamber 214. During the discharge phase, the compressed gas propels the annular piston 216 along the proximal direction (e.g., from center to left). Figure 3 (From the center to the right) pushes the fluid out of the annular fluid chamber 212 to the manifold 208.

[0101] In other examples, different types of accumulators can be used. For example, in addition to the annular piston 216 and the annular gas chamber 214, a bladder or diaphragm can be used to store pressurized fluid in the annular fluid chamber 212 and facilitate the discharge of fluid from it.

[0102] like Figure 2-3 As shown, EHA 200 may include an external fluid line 218 (e.g., an external conduit) that fluidly couples manifold 208 to the second chamber 118 of hydraulic cylinder actuator 104. For example, external fluid line 218 can connect ports in manifold 208 (as described below) Figure 11The manifold 208 is coupled to a corresponding port in the accumulator head 217, and the port of the accumulator head 217 is fluidly coupled to the second chamber 118 through fluid passages in the accumulator head 217 and the hydraulic cylinder 106. In other example embodiments, in addition to using an external fluid line 218, a passage may be formed within the housing 202 (e.g., in the second housing portion 206) to fluidly couple the manifold 208 to the second chamber 118.

[0103] In one example, manifold 208 may include an electro-hydraulic valve (e.g., metering valve 146) mounted therein. Such an electro-hydraulic valve is electrically actuated, for example, by a solenoid / solenoid valve. In some solenoid valves, the solenoid / solenoid valve coil is encapsulated in a sealed housing, which is pressurized or filled with a fluid such as air or oil. When the solenoid / solenoid valve coil is energized, it generates heat, which causes the fluid or air within the solenoid / solenoid valve housing to expand. This expansion generates pressure that can affect valve operation and potentially damage the solenoid / solenoid valve coil. In this example, to provide air ventilation for the solenoid / solenoid valve and prevent these problems, housing 202 (e.g., second housing portion 206) may include one or more vents 220, formed in a circular array around housing 202. The vents 220 allow any excessive pressure or fluid to escape. This venting / venting function ensures that the solenoid / solenoid valve coil remains at a safe operating temperature and ensures reliable, continuous valve operation. In addition, exhaust / ventilation can help prevent contamination of the fluids or gases controlled by the valve by preventing any fluid or gas from entering the solenoid valve housing.

[0104] According to the example implementation, Figure 5 A perspective view of the first housing portion 204 and the component 205 disposed therein is shown. Figure 6 A cross-sectional side view of the first housing portion 204 and the components 204 disposed therein is shown. Figure 5-6 They were described together.

[0105] The first housing portion 204 may include a lug mount 300 having a hole 302. The lug mount 300 is configured to protrude to facilitate mounting the EHA 200 to the machine frame, for example, via fasteners provided through the hole 302. Other mounting configurations may be used, such as clevis clips, trunnion mounts, or flange mounts.

[0106] like Figure 6 As shown, the first housing portion 204 may have an internal thread 304. The second housing portion 206 may have an external thread configured to engage with the internal thread 304 to couple the second housing portion 206 to the first housing portion 204.

[0107] Component 205 is disposed within an inner cavity of the first housing portion 204. Component 205 includes a pump-motor housing 306 disposed or received within the first housing portion 204. The first housing portion 204 and the pump-motor housing 306 define an inner cavity 307 in which a motor 308 is integrated with a pump 310.

[0108] The pump 310 described herein is an internal gear pump, used as an example for illustration. However, other types of pumps, such as piston pumps, cycloidal pumps, external gear pumps, or vane pumps, may be used.

[0109] The motor 308 includes a stator 312, which is fixedly positioned within the inner cavity 307 of the pump-motor housing 306. The stator 312 may have a wire winding 314 wound with respect to the body of the stator 312 (e.g., a lamination assembly), which generates a magnetic field when current is supplied through the wire winding 314. For example, as... Figure 4 As shown, the EHA 200 includes an electrical connector 222 that is mounted to the first housing portion 204 and configured to be connected to a power source (e.g., a battery or generator). The electrical connector 222 is also electrically coupled to a wire winding 314 to provide power thereto.

[0110] review Figure 6 The motor 308 also includes a rotor 316 positioned within the stator 312. The motor 308 may further include a magnet 318 mounted to the rotor 316, the magnet being located within an annular space between the stator 312 and the rotor 316. The magnet 318 is configured to interact with a magnetic field generated by the wire windings 314 of the stator 312, thereby causing the rotor 316 to rotate and generate torque. In other example embodiments, different types of motors that do not include permanent magnets may be used. Examples of motor types that may be used include induction motors, surface-mount permanent magnet motors, built-in permanent magnet motors, brushless DC motors, wound rotor motors, and switched reluctance motors.

[0111] Pump 310 is at least partially mounted within the rotor 316 and stator 312 of motor 308. Pump 310 has a cylindrical protrusion 320 formed as part of pump-motor housing 306 and extending axially or longitudinally within assembly 205. Pump 310 also includes a cylindrical protrusion 322 formed as part of first housing portion 204 and extending axially or longitudinally within assembly 205 toward the cylindrical protrusion 320 of pump-motor housing 306.

[0112] The cylindrical protrusions 320 and 322 face each other and form a space between them, in which components of the pump 310 are disposed such that the cylindrical protrusions 320 and 322 surround or clamp the components of the pump 310. Thus, the cylindrical protrusions 320 and 322 are configured as the pump housing 323.

[0113] The cylindrical protrusion 322 has an annular groove or recess that accommodates the outer bushing 324. The cylindrical protrusion 320 may similarly have an annular groove or recess that accommodates other outer bushings similar to the outer bushing 324.

[0114] Component 205 includes a generally cylindrical drive flange 328. The drive flange 328 is rotatably coupled to the rotor 316 of the motor 308 such that when the rotor 316 rotates, the drive flange 328 also rotates. For example, the drive flange 328 can be press-fitted into the rotor 316. Other structures such as keyway structures, spline structures, self-retaining tapered structures, etc., can also be used alternatively to couple the rotor 316 to the drive flange 328.

[0115] Pump 310 also includes an annular gear 330, which is axially clamped between cylindrical protrusions 320 and 322. The annular gear 330 has internal teeth formed on its inner circumferential surface. In one example, the annular gear 330 is integrated with a drive flange 328, such that the annular gear 330 and the drive flange 328 form a single component. In another example, the annular gear 330 may be a separate component coupled to the drive flange 328 (e.g., via a key-keyway structure, spline structure, self-retaining tapered structure, etc.).

[0116] like Figure 6 As shown, the outer bushing 324 is radially positioned between the outer peripheral surface of the cylindrical protrusion 322 and the inner peripheral surface of the drive flange 328. The outer bushing 324 serves as a bearing to support the rotation of the drive flange 328 and the ring gear 330 with minimal friction.

[0117] Pump 310 has a pump shaft 332 on which a pump pinion 334 (e.g., a spur gear with external teeth formed on its outer circumferential surface) is mounted or integrated. The external teeth of the pump pinion 334 engage with the internal teeth of the ring gear 330. Furthermore, the pump pinion 334 is offset relative to the ring gear 330, that is, the center of rotation of the pump pinion 334 is eccentric or offset relative to the corresponding center of rotation of the ring gear 330.

[0118] The cylindrical protrusion 320 has a cavity for receiving the pump shaft 332, and a first inner bushing 336 is radially located between the outer peripheral surface of the pump shaft 332 and the inner peripheral surface of the cylindrical protrusion 320. Similarly, the cylindrical protrusion 322 has a hole or cavity for receiving the other end of the pump shaft 332, and a second inner bushing 338 is radially located between the outer peripheral surface of the pump shaft 332 and the inner peripheral surface of the cylindrical protrusion 322.

[0119] The inner bushings 336 and 338 act as bearings, supporting the rotation of the pump shaft 332 with minimal friction. Since the pump shaft 332 is eccentrically positioned from the ring gear 330, the inner bushings 336 and 338 (which support the pump shaft 332) are also eccentrically positioned relative to the outer bushing 324 (which supports the drive flange 328).

[0120] The ring gear 330 and the pump pinion 334 are axially supported inside by a thrust plate 340 disposed on one side of the ring gear 330 and the pump pinion 334. In this way, the pump pinion 334 and the ring gear 330 are located or sandwiched between the thrust plate 340 and the cylindrical protrusion 322.

[0121] The thrust plate 340 is supported by the cylindrical protrusion 320. Specifically, the thrust plate 340 intersects with the cylindrical protrusion 320. The thrust plate 340 is configured as a floating component, which can move axially to compensate for any axial clearance and reduce internal leakage within the pump 310.

[0122] like Figure 5 As shown, pump 310 has a first pump port 342 (e.g., representing first pump port 122) and a second pump port 344 (e.g., representing second pump port 126). Pump 310 can be configured as a bidirectional pump. Specifically, the first pump port 342 can operate as an inlet port configured to receive fluid from hydraulic cylinder actuator 104, and the second pump port 344 can operate as an outlet or discharge port for supplying fluid discharged from pump 310 to hydraulic cylinder actuator 104. In this operating mode, pump pinion 334 and ring gear 330 rotate in a first rotational direction, and piston 108 can move in the first direction.

[0123] In another operating mode, the first pump port 342 is operable as a discharge port for supplying fluid discharged from the pump 310 to the hydraulic cylinder actuator 104, while the second pump port 344 is operable as an inlet port for receiving fluid from the hydraulic cylinder actuator 104. In this operating mode, the pump pinion 334 and the ring gear 330 rotate in a second rotational direction opposite to the first rotational direction, and the piston 108 can move in the second direction opposite to the first direction.

[0124] Furthermore, pump 310 can operate in either pumping mode or motor mode. In pumping mode, pump 310 supplies pressurized fluid to hydraulic cylinder actuator 104 to drive piston 108 against resistance load. In motor mode, the fluid returning from hydraulic cylinder actuator 104 is high-pressure fluid, which can drive pump 310 and motor 308 in regenerative mode.

[0125] In one example, component 205 may also include a first cooling port 346 and a second cooling port 348. Fluid supplied by accumulator 102 (when accumulator 102 is in discharge mode) may first flow through one of the cooling ports 346, 348 to the inner chamber 307 to cool motor 308, and then through the other cooling port 346, 348 to the hydraulic cylinder actuator 104.

[0126] Similarly, fluid returning from the hydraulic cylinder actuator 104 to the accumulator 102 (when the accumulator 102 is in charging mode) can first flow through one of the cooling ports 346 and 348 to the inner chamber 307 to cool the motor 308, and then flow through the other cooling port 346 and 348 to the accumulator 102. As described in more detail below, Figure 3-4 The connector module 210 shown includes corresponding ports to pump ports 342, 344 and cooling ports 346, 348 to facilitate guiding or routing fluid flow to and out of the motor 308 and pump 310 assembly 205.

[0127] Next, assuming pump 310 rotates in a given direction, its operation will be described. However, it should be understood that pump 310 can also operate in other directions, in which case the operation of the ports and fluid volume will be reversed.

[0128] During operation, the rotor 316 of the motor 308 drives the ring gear 330 via the drive flange 328, causing the ring gear 330 to rotate, which in turn causes the pump pinion 334 to rotate. As described above, the pump pinion 334 rotates eccentrically relative to the ring gear 330. In other words, the longitudinal axis around which the pump pinion 334 rotates is offset from the corresponding longitudinal axis around which the ring gear 330 rotates.

[0129] When the external teeth of the pump pinion 334 separate or disengage from the internal teeth of the ring gear 330, they form an expansion volume (i.e., an expansion chamber). This expansion volume generally represents multiple pockets formed between the separating teeth. This expansion volume acts as the suction cavity formed between the separating teeth on the suction side of the pump 310, which is fluidly coupled to the inlet port (e.g., the first pump port 342). Therefore, fluid from the inlet port fills the expansion volume between the teeth.

[0130] The fluid is then conveyed by the external teeth of the pump pinion 334 and the internal teeth of the ring gear 330 to another chamber or volume on the discharge side of the pump 310, which is fluidly coupled to the outlet port (e.g., the second pump port 344). The meshing of the gear teeth of the pump pinion 334 and the ring gear 330 discharges the fluid, and the fluid is then supplied to the outlet port. Thus, when the teeth of the pump pinion 334 and the ring gear 330 interlock on the discharge side of the pump 310, the volume is reduced and the fluid is squeezed out under pressure.

[0131] When the external teeth of the pump pinion 334 mesh with the internal teeth of the ring gear 330, they form a seal between the expansion volume of the low-pressure fluid received from the inlet port and the volume between the teeth that are meshing or about to mesh at the outlet. The seal created by the meshing teeth forces the fluid out of the discharge port and prevents the fluid from flowing back towards the inlet port.

[0132] In addition, such as Figure 6 As shown, pump 310 includes a crescent-shaped sealing assembly comprising an inner crescent portion 350 and an upper or outer crescent portion 352. The terms "inner" and "outer" refer to the radial positioning of the crescent, wherein the inner crescent portion 350 is disposed radially inward relative to the outer crescent portion 352.

[0133] The inner crescent portion 350 and the outer crescent portion 352 are axially supported within the internal space between the ring gear 330 and the pump pinion 334 by a pivot or locating pin 354. See also Figure 6 The positioning pin 354 is partially disposed in the blind hole formed in the columnar protrusions 320 and 322 and extends through the positioning pin through hole and the crescent portion 350 and 352 in the thrust plate 340.

[0134] With this configuration, the inner crescent portion 350 and the outer crescent portion 352 are axially held in place by the locating pin 354, which also maintains the orientation of the crescent portions 350 and 352. In this way, the locating pin 354 axially supports the crescent-shaped sealing assembly (inner crescent portion 350 and outer crescent portion 352).

[0135] During operation of pump 310, as the pump pinion 334 and ring gear 330 rotate, the crescent sections 350 and 352 divide the fluid as it is drawn from the low-pressure intake expansion volume and transported to the volume coupled to the discharge port. Therefore, the crescent sections 350 and 352 can form a seal between the low-pressure and high-pressure volumes.

[0136] Specifically, the outer surface (i.e., the radially outward surface) of the outer crescent portion 352 intersects with the inner teeth of the ring gear 330, thereby forming a seal between them. This effective seal between the outer surface of the outer crescent portion 352 and the inner teeth of the ring gear 330 prevents leakage from the high-pressure volume to the low-pressure volume. The term "stop" or "block" fluid flow as used herein refers to essentially stopping fluid flow except for, for example, a very small number of drops per minute.

[0137] Similarly, the inner surface of the inner crescent portion 350 (i.e., the radially inward surface) intersects with the outer teeth of the pump pinion 334, thereby forming a seal between them. The effective seal between the inner surface of the inner crescent portion 350 and the outer teeth of the pump pinion 334 prevents leakage from the high-pressure volume to the low-pressure volume.

[0138] As described above, the connector module 210 of the EHA 200 fluidly couples the components 205 (motor 308 and pump 310) to the manifold 208. Therefore, the connector module 210 is configured to guide fluid between the pump ports 342, 344 (e.g., inlet and outlet ports) of the pump 310 and the manifold 208, and also to guide cooling fluid (e.g., fluid supplied by or provided to the accumulator 102) between the components 205 and the manifold 208 (which is fluidly coupled to the annular fluid chamber 212 of the accumulator 102).

[0139] According to the example embodiment, Figure 7 A partial perspective cross-sectional view of the EHA 200 is shown, showing the connector module 210 mounted to the manifold 208; Figure 8 A rear view of connector module 210 is shown. Figure 7 Component 205 is not shown to show details of connector module 210. Figure 8 The rear or proximal end of connector module 210 is shown, which intersects with component 205 disposed within the first housing portion 204.

[0140] Connector module 210 includes a first port 400 aligned with and in fluid communication with a first pump port 342, and a second port 402 aligned with and in fluid communication with a second pump port 344. Furthermore, connector module 210 may also include a first cooling port 404 aligned with and in fluid communication with a first cooling port 346 of assembly 205. For example, the first cooling port 404 can fluidly couple a reverse shuttle valve 130 (located in manifold 208) to the inner chamber 307 of assembly 205. This connection between the reverse shuttle valve 130 and the first cooling port 404 represents, for example, the combination described above. Figure 1 The described booster flow line 132.

[0141] The connector module 210 may also include a second cooling port 406, which is aligned with and in fluid communication with the second cooling port 348 of the assembly 205. For example, the second cooling port 406 may fluidly couple the annular fluid chamber of the accumulator 102 to the inner chamber 307 of the assembly 205.

[0142] Manifold 208 integrates various valves of hydraulic system 100. Manifold 208 is configured to supply fluid to and receive fluid from hydraulic cylinder actuator 104 and accumulator 102, and also to supply fluid to and receive fluid from assembly 205 via connector module 210.

[0143] According to the example embodiment, Figure 9 A partial perspective cross-sectional view of the EHA 200 is shown, revealing manifold 208; Figure 10 The rear view of manifold 208 is shown; Figure 11 A side view of manifold 208 is shown. Figure 9 Component 205 or connector module 210 is not shown in order to show details of manifold 208. Figure 10 The rear or proximal end of connector module 210 is shown, which intersects with connector module 210. Manifold 208 may have external threads that engage with internal threads in second housing portion 206 to mount manifold 208 within second housing portion 206.

[0144] Manifold 208 includes a cavity in which valves of hydraulic system 100 are mounted, and also includes a fluid passage connecting the cavity. Manifold 208 also includes ports and fluid passages that deliver fluid to and from hydraulic cylinder actuator 104 and accumulator 102 on one side of manifold 208 and connector module 210 (fluidly coupled to assembly 205) on the other side of manifold 208.

[0145] refer to Figure 10 Manifold 208 includes a first manifold port 500 and a second manifold port 502, which are aligned and in fluid communication with ports 400, 402 of connector module 210 (which are fluidly coupled to pump ports 342, 344 of assembly 205). Manifold 208 also includes a first manifold cooling port 504, which allows fluid from accumulator 102 to the inner chamber 307 of assembly 205 to cool motor 308. Manifold 208 also includes a second manifold cooling port 506, which allows fluid already supplied from accumulator 102 to the inner chamber 307 to flow back from the inner chamber 307 to a reverse shuttle valve 130, which is positioned... Figure 11 In the cavity 508 shown on one side of the manifold 208.

[0146] refer to Figure 10The manifold 208 also includes a cavity 510 for receiving a pressure relief valve 148 of the hydraulic system 100, and a cavity 512 for receiving a shuttle valve 144 of the hydraulic system 100. The manifold 208 also includes a cavity 514 for receiving a metering valve 146 of the hydraulic system 100.

[0147] Manifold 208 also receives and supplies fluid into and out of chambers 116, 118 of the hydraulic cylinder actuator 104. (Reference) Figure 11 The manifold includes a rod-side chamber port 516, which is connected via... Figure 2-3 The external fluid line 218 shown is fluidly coupled to the second chamber 118 of the hydraulic cylinder actuator 104. Figure 11 It is also shown that the manifold 208 includes a first annular groove 518 and a second annular groove 520, in which corresponding seals (e.g., O-rings) can be provided to seal the manifold 208 relative to the inner surface of the second housing portion 206.

[0148] Figure 12 A front view of manifold 208 according to an example embodiment is shown. As shown, manifold 208 includes an accumulator port 522 that is fluidly coupled to an annular fluid chamber 212 of accumulator 102. With this configuration, accumulator port 522 can deliver fluid to and from the annular fluid chamber 212 of accumulator 102. Manifold 208 also includes a head-side chamber port 524 that is fluidly coupled to a first chamber 116 of hydraulic cylinder actuator 104.

[0149] As an example of how fluid flows through EHA 200, during piston 108 retraction, fluid is discharged from the first chamber 116 and then flows through the head-side chamber port 524 of manifold 208. A portion of the fluid flows through the second manifold port 502, through the second port 402 of connector module 210 to the second pump port 344.

[0150] Another portion of the fluid flows to the reverse shuttle valve 130, and then through the second manifold cooling port 506, through the second cooling port 406 of the connector module 210, through the second cooling port 348 of the assembly 205 to the inner chamber 307 of the assembly 205 to cool the motor 308. The fluid then returns from the inner chamber 307, through the first cooling port 346 of the assembly 205, through the first cooling port 404 of the connector module 210, to the first manifold cooling port 504, through the accumulator port 522, and then to the annular fluid chamber 212 of the accumulator 102 to charge the accumulator 102.

[0151] Fluid from the first pump port 342 is supplied to the first port 400 of the connector module 210, and then through the rod-side chamber port 516 of the manifold 208. The fluid then... Figure 2-3The external fluid line 218 shown is supplied to the second chamber 118 of the hydraulic cylinder actuator 104.

[0152] This fluid flow path can be reversed during piston 108 extension.

[0153] The configuration of the EHA 200 offers several advantages. The accumulator 102 is integrated within the housing 202 of the EHA 200 and surrounds the cylinder 106 of the hydraulic cylinder actuator 104. Compared to conventional EHAs, this configuration reduces the overall size and length of the EHA 200, where the accumulator is a separate component mounted near the hydraulic cylinder and connected to it via fluid lines.

[0154] Furthermore, by utilizing this configuration of the EHA200, in which the manifold 208, electro-hydraulic power unit 120 (e.g., assembly 205 of motor 308 and pump 310), hydraulic cylinder actuator 104 and accumulator 102 are integrated into a single housing (e.g., housing 202), many connections (fluid lines, fittings, couplings, etc.) are eliminated, thereby improving the reliability of the EHA 200.

[0155] Furthermore, as mentioned above, the accumulator 102 provides a low-pressure fluid, so the wall of the second housing portion 206 does not need to be thickened because it does not need to withstand high pressure. However, by embedding the accumulator 102 within the housing 202, it can be protected from debris or impacts that the EHA 200 may encounter.

[0156] In addition, integrating the valve of the EHA200 into the manifold 208 (which is also embedded in the housing 202) protects the valve from debris, impacts or collisions that the EHA200 may be subjected to.

[0157] Figure 13 This is a flowchart of an assembly method 600 for an EHA 200 according to an example embodiment. Method 600 may include one or more operations, functions, or actions, as shown in one or more of steps 602-614.

[0158] Although these steps are shown sequentially, they can also be executed in parallel and / or in a different order than that described herein. Furthermore, individual steps can be combined into fewer steps, split into more steps, and / or removed, depending on the desired implementation. It should be understood that, for the processes and methods disclosed herein, as well as other processes and methods disclosed herein, the flowchart illustrates one possible implementation of the functionality and operations of this example. Those skilled in the art will understand that other implementations are also included within the scope of this disclosure, where functionality can be executed in a different order than that shown or described, including substantially concurrent or reverse execution, depending on the functionality involved.

[0159] At block 602, method 600 includes mounting a component 205 of motor 308 and pump 310 in a first housing portion 204.

[0160] At block 604, method 600 includes providing a piston 108 for a hydraulic cylinder actuator 104, wherein the piston includes a rod 112, a piston head 110, and a gland 209. The term “provide” as used herein, and for example with respect to piston 108 or other components, includes any action that makes piston 108 or any other component available, such as bringing piston 108 or other components into the equipment or working environment for further processing (e.g., installing other components, etc.).

[0161] For example, at block 604, method 600 may include providing rod 112, attaching cap 209 to rod 112, attaching piston head 110 to rod 112, and then locking piston head 110 to rod 112 with a nut.

[0162] At block 606, method 600 includes coupling cylinder 106 of hydraulic cylinder actuator 104 to gland 209 such that piston head 110 is slidably received within cylinder 106. For example, gland 209 may have external threads and cylinder 106 may have corresponding internal threads to allow cylinder 106 to be screwed onto gland 209.

[0163] At block 608, method 600 includes mounting accumulator head 217 around cylinder 106.

[0164] At block 610, method 600 includes coupling a second housing portion 206 to an accumulator head 217 such that an annular space is formed between the second housing portion 206 and the cylinder 106 of the hydraulic cylinder actuator 104. For example, the accumulator head 217 may have external threads, and the second housing portion 206 may have corresponding internal threads, thereby allowing the second housing portion 206 to be screwed onto the accumulator head 217.

[0165] At block 612, method 600 includes inserting an annular piston 216 of accumulator 102 into an annular space such that the annular piston 216 divides the annular space into an annular fluid chamber 212 and an annular gas chamber 214.

[0166] At block 614, method 600 includes coupling a first housing portion 204 with a component 205 disposed therein to a second housing portion 206. For example, the first housing portion 204 may have an internal thread 304, and the second housing portion 206 may have an external thread configured to engage with the internal thread 304 to couple the second housing portion 206 to the first housing portion 204.

[0167] Method 600 may also include additional steps for assembling the EHA 200 described herein.

[0168] The above detailed description, taken in conjunction with the accompanying drawings, illustrates various features and operations of the disclosed system. The exemplary embodiments described herein are not intended to limit the invention. Certain aspects of the disclosed system can be arranged and combined in a variety of different configurations, all of which are contemplated herein.

[0169] Furthermore, unless the context otherwise requires, the features shown in each diagram can be used in combination with each other. Therefore, these diagrams should generally be considered as components of one or more overall implementations, but it should be understood that not all features shown are required for every implementation.

[0170] Furthermore, any enumeration of elements, blocks, or steps in this specification or claims is for clarity purposes. Therefore, such enumeration should not be construed as requiring or implying that these elements, blocks, or steps must follow a specific arrangement or be performed in a specific order.

[0171] Furthermore, the device or system may be used or configured to perform the functions shown in the figure. In some cases, components of the device and / or system may be configured to perform these functions such that the actual configuration and structure of these components (including hardware and / or software) enable such performance. In other examples, components of the device and / or system may be arranged to adapt to, be able to, or be suited to perform these functions, for example, when operating in a particular manner.

[0172] The terms “substantially” or “approximately” indicate that the described characteristic, parameter, or value does not need to be precisely achieved, but may vary or differ, including, for example, tolerances, measurement errors, measurement accuracy limitations, and other factors known to those skilled in the art, but these variations or differences will not prevent the characteristic from providing the desired effect.

[0173] The arrangements described herein are for illustrative purposes only. Therefore, those skilled in the art will understand that other arrangements and other elements (e.g., machines, interfaces, operations, commands, and operation groups) can be used, and certain elements may be omitted entirely depending on the desired outcome. Furthermore, many of the elements described herein are functional entities that can be implemented as discrete or distributed components, or combined with other components, in any suitable combination and location.

[0174] While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for illustrative purposes only and are not limiting, and their true scope is indicated by the full scope of the following claims and their equivalents. Furthermore, the terminology used herein is for describing particular embodiments only and is not limiting.

[0175] Therefore, embodiments of this disclosure may relate to one of the exemplary embodiments (EEEs) listed below.

[0176] EEE1 is an electro-hydraulic actuator comprising: a housing; a hydraulic cylinder actuator disposed within the housing and including a cylinder and a piston, wherein the piston divides the internal space of the cylinder into a first chamber and a second chamber, and wherein the hydraulic cylinder actuator is unbalanced such that a first fluid flow rate of fluid supplied to the first chamber or the second chamber to drive the piston in a given direction differs from a second fluid flow rate of fluid discharged from the other chamber as the piston moves; an accumulator disposed within the housing and including an annular fluid chamber surrounding the cylinder of the hydraulic cylinder actuator, wherein the accumulator is configured to provide a pressurized fluid flow from the annular fluid chamber or to receive an excess fluid flow at the annular fluid chamber, wherein the pressurized fluid flow or the excess fluid flow includes a difference between the first fluid flow rate and the second fluid flow rate; and an assembly disposed within the housing comprising: (i) a pump configured as a bidirectional fluid flow source, and (ii) a motor configured to drive the pump in opposite directions of rotation to provide fluid flow to the first chamber or the second chamber of the hydraulic cylinder actuator, thereby driving the piston.

[0177] EEE2 is an electro-hydraulic actuator of EEE1, wherein the accumulator further includes: an annular piston disposed around the cylinder of the hydraulic cylinder actuator, wherein the annular piston is slidably accommodated within an annular space formed between the housing of the hydraulic cylinder actuator and the cylinder; and an annular gas chamber surrounding the cylinder, wherein the annular piston separates the annular fluid chamber from the annular gas chamber.

[0178] EEE3 is an electro-hydraulic actuator of any one of EEE1-2, wherein the assembly includes an internal chamber, a motor and a pump disposed in the internal chamber, wherein a pressurized fluid flow supplied from an annular fluid chamber of an accumulator flows through the internal chamber to cool the motor before flowing to the hydraulic cylinder actuator, and wherein excess fluid flow from the hydraulic cylinder actuator flows through the internal chamber to cool the motor before flowing to the annular fluid chamber of the accumulator.

[0179] EEE4 is an electro-hydraulic actuator of any of EEE1-3, wherein the accumulator further includes an accumulator head with external threads, and wherein the housing includes an internal thread that engages with the external threads of the accumulator head to mount the housing to the accumulator head.

[0180] EEE 5 is an electro-hydraulic actuator of any one of EEE1-4, wherein the housing includes: a first housing portion in which an assembly of a motor and a pump is disposed; and a second housing portion coupled to the first housing portion, wherein the second housing portion includes an accumulator and a hydraulic cylinder actuator such that the cylinder of the hydraulic cylinder actuator is disposed within the second housing portion, and the accumulator is disposed in an annular space between the cylinder and the second housing portion.

[0181] EEE 6 is an electro-hydraulic actuator of any one of EEE 1-5, wherein the motor includes: (i) a stator fixedly positioned within a housing, and (ii) a rotor positioned within the stator and rotatable relative to the stator, and wherein the pump is a gear pump at least partially positioned within the rotor of the motor, wherein the gear pump includes: (i) a drive flange rotatably coupled to the rotor of the motor, (ii) an annular gear coupled to the drive flange and configured to rotate therewith, (iii) a pump pinion disposed within the annular gear such that the external teeth of the pump pinion engage with the internal teeth of the annular gear, and (iv) a plurality of ports including: a first pump port and a second pump port, wherein when the rotor rotates, the drive flange and the annular gear rotate accordingly, causing the pump pinion to rotate within the annular gear, such that fluid is drawn in through the first pump port and discharged to the second pump port for discharge.

[0182] The EEE7 is an electro-hydraulic actuator of the EEE6, and also includes: a pump-motor housing including a first cylindrical protrusion, wherein the housing includes a second cylindrical protrusion facing the first cylindrical protrusion, such that a ring gear and a pump pinion are located between the first cylindrical protrusion and the second cylindrical protrusion.

[0183] EEE8 is an electro-hydraulic actuator of any of EEE1-7, and further includes: a manifold disposed within a housing and fluidly coupled to a pump, an accumulator and a hydraulic cylinder actuator, wherein the manifold includes multiple ports, a cavity configured to receive a respective valve therein, and a fluid passage.

[0184] EEE 9 is an electro-hydraulic actuator of EEE8, wherein the manifold includes: a head-side chamber port fluidly coupled to a first chamber of a hydraulic cylinder actuator; and a rod-side chamber port fluidly coupled to a second chamber of a hydraulic cylinder actuator.

[0185] The EEE10 is an electro-hydraulic actuator of the EEE9, in which the rod-side chamber port is fluidly coupled to a second chamber via an external fluid line located outside the housing.

[0186] EEE11 is an electro-hydraulic actuator of any of EEE8-10, wherein the manifold includes an accumulator port fluidly coupled to an annular fluid chamber of an accumulator.

[0187] EEE12 is an electro-hydraulic actuator of any of EEE8-11, wherein the pump includes a first pump port and a second pump port, wherein the pump is configured to draw in fluid through the first pump port and discharge fluid to the second pump port, wherein the manifold further includes: a first manifold port fluidly coupled to the first pump port; and a second manifold port fluidly coupled to the second pump port.

[0188] EEE 13 is an electro-hydraulic actuator of EEE 12, wherein the assembly includes a first cooling port and a second cooling port in fluid communication with an inner chamber of the assembly in which a motor is disposed, wherein the manifold includes: a first manifold cooling port fluidly coupled to the first cooling port of the assembly; and a second manifold cooling port fluidly coupled to the second cooling port of the assembly, wherein pressurized fluid supplied from the annular fluid chamber of the accumulator flows through the first manifold cooling port to the first cooling port of the assembly, and then through the inner chamber to cool the motor before being discharged from the inner chamber to the second manifold cooling port via the second cooling port of the assembly.

[0189] The EEE 14 is an electro-hydraulic actuator of the EEE 13, and also includes a connector module between the manifold and the assembly, wherein the connector module is configured to fluidly couple the assembly to the manifold.

[0190] EEE 15 is an electro-hydraulic actuator of EEE 14, wherein the connector module includes: a first port fluidly coupled to a first pump port and a first manifold port; a second port fluidly coupled to a second pump port and a second manifold port; a first cooling port fluidly coupled to a first cooling port of the component and a first manifold cooling port; and a second cooling port fluidly coupled to a second cooling port of the component and a second manifold cooling port.

[0191] EEE 16 is an electro-hydraulic actuator of any of EEE 8-15, wherein the manifold includes at least one valve electrically actuated by a solenoid valve, and wherein the housing includes one or more vent holes that allow expansion air generated by the operation of the solenoid valve to be vented into the environment of the housing.

[0192] EEE 17 is an electro-hydraulic actuator of any of EEE 8-16, wherein the manifold includes: at least one annular groove in which a seal is provided to seal the manifold to the inner surface of the housing.

[0193] EEE 18 is a method of assembling an electro-hydraulic actuator according to any one of EEE 1-17. The method includes: mounting an assembly of a motor and a pump in a first housing portion; providing a piston for a hydraulic cylinder actuator, wherein the piston includes a rod, a piston head, and a gland; connecting a cylinder of the hydraulic cylinder actuator to the gland such that the piston head is slidably received within the cylinder; mounting an accumulator head around the cylinder; coupling a second housing portion to the accumulator head such that an annular space is formed between the second housing portion and the cylinder of the hydraulic cylinder actuator; inserting an annular piston of the accumulator into the annular space such that the annular piston divides the annular space into an annular fluid chamber and an annular gas chamber; and coupling the first housing portion, together with the assembly disposed therein, to the second housing portion.

[0194] EEE 19 is a method of EEE 18, further comprising: mounting a manifold to a second housing portion for fluid coupling to an annular fluid chamber of the accumulator and a hydraulic cylinder actuator; and mounting a connector module to the manifold prior to coupling the first housing portion to the second housing portion.

[0195] EEE 20 is a method of EEE 19, wherein a piston head divides the internal space of a cylinder into a first chamber and a second chamber, and wherein the method further includes: attaching an external conduit to a second housing portion to fluidly couple the second chamber to a manifold.

Claims

1. An electro-hydraulic actuator, comprising: case; A hydraulic cylinder actuator is disposed within a housing and includes a cylinder and a piston, wherein the piston divides the internal space of the cylinder into a first chamber and a second chamber, and wherein the hydraulic cylinder actuator is unbalanced such that a first fluid flow rate supplied to the first chamber or the second chamber to drive the piston in a given direction is different from a second fluid flow rate of fluid discharged from the other chamber when the piston moves. An accumulator disposed within a housing and including an annular fluid chamber surrounding a cylinder of a hydraulic cylinder actuator, wherein the accumulator is configured to provide a pressurized fluid flow from the annular fluid chamber or receive an excess fluid flow at the annular fluid chamber, wherein the pressurized fluid flow or the excess fluid flow includes a difference between a first fluid flow rate and a second fluid flow rate; and An assembly disposed within a housing, the assembly comprising: (i) a pump configured as a bidirectional fluid flow source, and (ii) an electric motor configured to drive the pump in opposite directions of rotation to provide fluid flow to a first or second chamber of a hydraulic cylinder actuator to drive a piston.

2. The electro-hydraulic actuator according to claim 1, wherein, The energy storage device also includes: An annular piston is arranged around the cylinder of a hydraulic cylinder actuator, wherein the annular piston is slidably accommodated within an annular space formed between the housing of the hydraulic cylinder actuator and the cylinder; and The annular gas chamber surrounds the cylinder, wherein the annular piston separates the annular fluid chamber from the annular gas chamber.

3. The electro-hydraulic actuator according to claim 1, wherein, The component includes an internal chamber in which a motor and a pump are disposed, wherein a pressurized fluid flow from an annular fluid chamber of an accumulator flows through the internal chamber to cool the motor before flowing to the hydraulic cylinder actuator, and wherein excess fluid flow from the hydraulic cylinder actuator flows through the internal chamber to cool the motor before flowing to the annular fluid chamber of the accumulator.

4. The electro-hydraulic actuator according to claim 1, wherein, The accumulator also includes an accumulator head with external threads, wherein the housing includes an internal thread that engages with the external threads of the accumulator head to mount the housing to the accumulator head.

5. The electro-hydraulic actuator according to claim 1, wherein, The housing includes: The first housing section houses the motor and pump assembly; and A second housing portion is coupled to the first housing portion, wherein the second housing portion includes the accumulator and the hydraulic cylinder actuator, such that the cylinder of the hydraulic cylinder actuator is disposed within the second housing portion, and the accumulator is disposed within the annular space between the cylinder and the second housing portion.

6. The electro-hydraulic actuator according to claim 1, wherein, The motor includes (i) a stator fixedly positioned within a housing, and (ii) a rotor positioned within the stator and rotatable relative to the stator, wherein the pump is a gear pump, the gear pump being at least partially positioned within the rotor of the motor, wherein the gear pump includes: (i) a drive flange rotatably coupled to the rotor of the motor, (ii) an annular gear coupled to the drive flange and configured to rotate therewith, (iii) a pump pinion disposed within the annular gear such that the external teeth of the pump pinion engage with the internal teeth of the annular gear, and (iv) a plurality of ports including: a first pump port and a second pump port, wherein, when the rotor rotates, the drive flange and the annular gear rotate accordingly, causing the pump pinion to rotate within the annular gear, such that fluid is drawn in through the first pump port and discharged to the second pump port for discharge.

7. The electro-hydraulic actuator according to claim 6, further comprising: A pump-motor housing includes a first cylindrical protrusion, wherein the housing includes a second cylindrical protrusion facing the first cylindrical protrusion, such that the ring gear and the pump pinion are located between the first cylindrical protrusion and the second cylindrical protrusion.

8. The electro-hydraulic actuator according to claim 1, further comprising: A manifold disposed within a housing and fluidly coupled to a pump, accumulator, and hydraulic cylinder actuator, wherein the manifold includes multiple ports, a cavity configured to receive a corresponding valve therein, and a fluid passage.

9. The electro-hydraulic actuator according to claim 8, wherein, Manifolds include: The head-side chamber port, fluidly coupled to the first chamber of the hydraulic cylinder actuator; and The rod-side chamber port is fluidly coupled to the second chamber of the hydraulic cylinder actuator.

10. The electro-hydraulic actuator according to claim 9, wherein, The rod-side chamber port is fluidly coupled to the second chamber via an external fluid line located outside the housing.

11. The electro-hydraulic actuator of claim 8, wherein the manifold comprises: The accumulator port is fluidly coupled to the annular fluid chamber of the accumulator.

12. The electro-hydraulic actuator of claim 8, wherein the pump includes a first pump port and a second pump port, wherein the pump is configured to draw in fluid through the first pump port and discharge the fluid to the second pump port for discharge, wherein the manifold further includes: A first manifold port that is fluidly coupled to the first pump port; as well as A second manifold port that is fluidly coupled to the second pump port.

13. The electro-hydraulic actuator according to claim 12, wherein, The component includes a first cooling port and a second cooling port, the first cooling port and the second cooling port being in fluid communication with an internal cavity of the component in which the motor is disposed, wherein the manifold includes: A first manifold cooling port, which is fluidly coupled to a first cooling port of the component; and The second manifold cooling port is fluidly coupled to the second cooling port of the assembly, wherein a pressurized fluid flow from the annular fluid chamber of the accumulator flows through the first manifold cooling port to the first cooling port of the assembly, and then through the inner chamber to cool the motor before being discharged from the inner chamber through the second cooling port of the assembly to the second manifold cooling port.

14. The electro-hydraulic actuator according to claim 13, further comprising: A connector module located between a manifold and a component, wherein the connector module is configured to fluidly couple the component to the manifold.

15. The electro-hydraulic actuator according to claim 14, wherein, The connector module includes: The fluid is coupled to the first port of the first pump port and the first manifold port; Fluid coupling is connected to the second port of the second pump port and the second manifold port; The first cooling port is fluidly coupled to the first cooling port of the component and the first manifold cooling port; and The fluid is coupled to the second cooling port of the component and the second cooling port of the second manifold.

16. The electro-hydraulic actuator of claim 8, wherein the manifold includes at least one valve electrically actuated via a solenoid valve, and wherein the housing includes one or more vent holes allowing expansion air generated by the operation of the solenoid valve to be vented into the environment of the housing.

17. The electro-hydraulic actuator of claim 8, wherein the manifold comprises: At least one annular groove in which a seal is provided to seal the manifold relative to the inner surface of the housing.

18. A method for assembling an electro-hydraulic actuator, the method comprising: The motor and pump components are installed in the first housing section; A piston for a hydraulic cylinder actuator is provided, wherein the piston includes a rod, a piston head, and a gland; The cylinder of the hydraulic cylinder actuator is coupled to the gland so that the piston head can be slidably accommodated in the cylinder; Install the accumulator head around the cylinder; The second housing portion is coupled to the accumulator head, such that an annular space is formed between the second housing portion and the cylinder of the hydraulic cylinder actuator. The annular piston of the accumulator is inserted into the annular space, dividing the annular space into an annular fluid chamber and an annular gas chamber; and The first housing portion, together with the components disposed therein, is coupled to the second housing portion.

19. The method of claim 18, further comprising: The manifold is installed into the second housing section to fluidly couple the accumulator’s annular fluid chamber and the hydraulic cylinder actuator; as well as The connector module is installed into the manifold before the first housing portion is coupled to the second housing portion.

20. The method of claim 19, wherein the piston head divides the internal space of the cylinder into a first chamber and a second chamber, and wherein the method further comprises: An external pipe is installed into the second housing section to couple the fluid of the second chamber to the manifold.

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