Microelectromechanical System (MEMS) actuator with magnetic latch and method for manufacturing and using the same

Abstract

The electromechanical actuator introduced herein includes a stator assembly comprising a chamber partially defined along a central longitudinal axis through which a stator assembly is located, and a plunger assembly located within the chamber and moving along the central longitudinal axis between different positions during operation. The stator assembly may include a pair of contacts having an opening between them, and a triple ferromagnetic layer comprising a coil located between the triple ferromagnetic layers. The plunger assembly may include a magnet. When an electric current is applied to the coil, the triple ferromagnetic layer becomes magnetically polarized, thereby determining the motion of the plunger assembly by magnetically attracting or repelling the magnet contained within the plunger assembly.

Description

Technical Field

[0001] Various embodiments relate to electromechanical actuators, and more specifically, actuators designed for applications that require rapid movement, bistable latches, large latch forces relative to size, and / or large movement distances, and approaches to manufacturing and using such electromechanical actuators.

Background Art

[0002] An electromechanical actuator is a device that converts an electric current into mechanical movement. A solenoid actuator is a specific type of electromechanical actuator that provides linear movement between two positions. Solenoid actuators are used in a wide variety of applications including opening and closing of electrical contacts in relays, opening and closing of valves, latching and unlatching of doors or hatches. A solenoid actuator is constructed using a coil of wire wound around an open cavity or ferromagnetic core. A ferromagnetic armature (also called a "plunger" or "piston") can be positioned inside the coil or axially at one end of the coil. The current flowing through the coil produces a magnetic field that "draws in" the armature of the solenoid actuator. When the current flow is stopped, a spring returns the armature to its non-energized position. Some solenoid actuators are bistable (or "latch-type"). In such solenoid actuators, the plunger will be held at both ends of the movement distance using magnets or mechanical constraints. In the case of a bistable solenoid actuator, the current through the coil can be delivered in either direction to move the plunger from one end of the solenoid actuator to the other.

Summary of the Invention

Means for Solving the Problems

[0003] Overview of Electromechanical Actuators Generally speaking, the electromechanical actuators described herein are generally laminated devices manufactured by cutting thin sheets of material and then joining those thin sheets together in a stack, as will be discussed further below. Using successive cut / join iterations, the structures comprising the electromechanical actuators can be arranged in the same plane as each other in almost any arbitrary configuration. [Brief explanation of the drawing]

[0004] This patent or application includes at least one drawing made in color. A copy of this publication of the patent or application, accompanied by the color drawing, will be provided by the Secretariat upon request and payment of the required fees.

[0005] [Figure 1] Figure 1 includes a schematic illustration of a solenoid or actuator having a conventional electromagnetic configuration.

[0006] [Figure 2-1] Figure 2A includes cross-sectional views of various layers of an actuator according to various embodiments of the present disclosure.

[0007] [Figure 2-2] Figures 2B-C illustrate how the various layers of the electromechanical actuator shown in Figure 2A generally correspond to one of two “stacks,” namely, a static stack (also called the “stator assembly”) or an actuable stack (also called the “rotor assembly”) or a plunger assembly.

[0008] [Figure 3] Figure 3 includes a simplified schematic illustration of the latching behavior of the electromechanical actuator caused by the magnetic circuit in the "open position" and the "closed position".

[0009] [Figure 4]Figure 4 includes a schematic illustration showing how the current passing through the coil will result in a substantially constant magnetic force being applied to the plunger.

[0010] [Figure 5-1] Figures 5A-E illustrate the magnetic flux in the plunger assembly as it moves from a first position to a second position and then back to the first position. [Figure 5-2] Figures 5A-E illustrate the magnetic flux in the plunger assembly as it moves from a first position to a second position and then back to the first position.

[0011] [Figure 6] Figure 6 includes a perspective cross-sectional view illustrating how a flexible portion connected to the plunger assembly can restrict the movement of the plunger assembly relative to the stator assembly.

[0012] [Figure 7] Figure 7 includes schematic illustrations of cross-sectional views of the plunger assembly, contact assembly, and stator assembly.

[0013] [Figure 8] Figure 8 includes a cross-sectional view of the electromechanical actuator, as well as a schematic illustration of a possible assembly sequence.

[0014] [Figure 9] Figure 9 includes a high-level diagram of the process for fabricating an electromechanical actuator.

[0015] Embodiments are illustrated in the drawings as examples, not as limitations. While the drawings depict various embodiments for illustrative purposes, those skilled in the art will recognize that alternative embodiments can be adopted without departing from the principles of the present art. Therefore, although specific embodiments are shown in the drawings, the present art is adaptable to various modifications. [Modes for carrying out the invention]

[0016] Detailed Description Electromechanical actuators have been used historically in many contexts. Many devices that require electrically controlled motion can be driven by electromechanical actuators. Examples of such devices include valves, tactile feedback devices, and electromechanical relays. Low-power devices such as microprocessors can drive such actuators, activate switches (relays), and control electrical loads beyond their direct drive capabilities. Electromechanical actuators can also be used to drive many other useful loads in other applications, such as valves, optical elements such as mirrors or lenses, mechanical or electrical adjustment elements, fluid pressure modulators, or pumps.

[0017] FIG. 1 includes a schematic illustration of a solenoid or actuator having a conventional electromagnetic form. The conventional electromagnetic form includes a control coil 102 wound around a ferromagnetic core 104. Application of a current through the control coil 102 generates a magnetic field with a general orientation parallel to the axis of the coil 102. This magnetic field attracts the upper side of two contacts 108. The upper contact moves downward until it touches the lower contact 108. This closes the switch and allows current to flow from the power source to the load. When the current through the control coil 102 is interrupted by opening the control switch 106, the upper contact 108 is restored to its natural open position by the spring force.

[0018] Typically, conventional electromechanical actuators are at least several centimeters in both length and width. Their structures require coils of wire, which must be formed using bobbin winding machinery. The winding of the coils increases the complexity and thus the cost of producing such actuators. In contrast, the electromechanical actuators introduced here enable the use of planar circuit networks, reducing the complexity of forming coils and allowing the resulting device to be much smaller with dimensions of 1 millimeter (mm) × 6 mm × 6 mm or less. This enables the resulting device to be used in applications that require a small size.

[0019] Conventional solenoid actuators are typically not latched at the end positions of the stroke, and even in implementations where latching is considered a possibility, the latching is typically achieved using mechanical means. Mechanical latches add moving parts to the design, which increases their cost and reduces their reliability. The electromechanical actuators introduced here provide magnetic latches at each end of the stroke as a function of their design and do not require any additional components. The magnetic latches are completely passive and do not require any external energy to hold the plunger at both ends of the stroke.

[0020] Terminology A concise definition of the terms, abbreviations, and phrases used throughout this application is provided below.

[0021] The mention of "an embodiment" or "some embodiments" in this description means that the features described are included in at least one embodiment of the technology. Such expressions do not necessarily refer to the same embodiment, nor do they necessarily refer to alternative embodiments that are mutually exclusive of each other.

[0022] The terms "comprise," "comprising," and "comprised of" are not interpreted in an exclusive or exhaustive sense, but in an inclusive sense (i.e., "including but not limited to"). The term "based on" is also interpreted in an inclusive sense, not in an exclusive or exhaustive sense. Therefore, unless otherwise stated, the term "based on" is intended to mean "based at least in part on."

[0023] The terms “connected,” “coupled,” and any variations thereof are intended to include any direct or indirect connection or coupling between two or more elements. The connection or coupling may be physical, logical, or a combination thereof. For example, objects may be electrically or communicatively connected to one another without sharing a physical connection.

[0024] Figure 2A includes cross-sectional views of various layers of the electromechanical actuator 200 according to various embodiments of the present disclosure. Figures 2B-C, on the other hand, illustrate how the various layers of the electromechanical actuator 200 correspond to one of two “stacks,” namely, a static stack 232 (also called the “static assembly,” “stator assembly,” or simply the “stator”) or an actuated stack 234 (also called the “actuated assembly,” “rotor assembly,” “plunger assembly,” or “plunger”). As will be further discussed below, the plunger assembly 234 can be displaced vertically within the stator assembly 232 to controllably move the load 218.

[0025] Referring again to Figure 2A, the stator assembly 232 represents a group of layers, each having a chamber 236 partially defined along a central longitudinal axis 238. The central longitudinal axis 238 can roughly bisect the width of the electromechanical actuator 200. The substrate 202 may be the bottommost layer of the stator assembly 232. The substrate 202 may be a small block of insulating material on which functional components, such as relays or valves, are fabricated to complete the electromechanical device. The insulating material may be, for example, ceramic or glass. Insulation is not always necessary (for example, insulation may be useful if the electromechanical actuator 200 forms part of an electrical switch). Therefore, the substrate 202 may, as an alternative, consist of a non-insulating material on which functional components are fabricated to complete the electromechanical device. Some embodiments may not include the substrate 202 at all, in which case the load stop section 204A-B may be the bottommost layer of the electromechanical actuator 200.

[0026] From the perspective of "occupied area," it is generally desirable to make the electromechanical actuator 200 as small as possible, within the limits set by the current density. Cost and magnetic performance tend to scale favorably as the size decreases. For example, the actuation force may be proportional to the square root of the movable magnet mass of the electromechanical actuator 200 and the square root of the power consumed. Generally, the substrate 202 may be less than 4 mm thick (preferably less than 3 mm thick). The thickness of the substrate 202 may be fundamental to the operation of the electromechanical device and therefore may not depend much on the intended application of the electromechanical actuator 200. The shape, length, and width of the substrate 202 may vary depending on the intended application of the electromechanical device 200. However, in some embodiments, the length may not exceed 10 mm, 20 mm, 25 mm, or 50 mm, and the width may not exceed 10 mm, 20 mm, 25 mm, or 50 mm. Thus, the surface area of ​​the substrate 202 is 100 mm². 2 (i.e., 10mm x 10mm), 400mm 2(i.e., 20mm x 20mm), 625mm 2 (i.e., 25mm x 25mm), or 2,500mm 2 (i.e., less than 50 mm × 50 mm) In other embodiments, since there are no basic size constraints on the electromechanical actuator 200, the length and / or width may exceed 50 mm, and therefore the surface area of ​​the substrate 202 may be 625 mm². 2 It is acceptable to exceed this limit.

[0027] The stator assembly 232 and the plunger assembly 234 can be connected to each other by one or more flexures, which are intended to restrict the lateral movement of the plunger assembly 234 and control, suppress, or limit its tilt as the plunger assembly 234 moves vertically within the chamber of the stator assembly 232. Specifically, the flexures may be designed to provide a desired axial force when the plunger assembly 234 is latched, such that the axial force provided by the flexures counteracts the latching force and allows and assists faster movement of the plunger assembly 234 when current is applied to the coils in the stator assembly 232. In some embodiments, multiple flexures are used to restrict the torsional movement ("tilt") and horizontal movement of the plunger assembly 234, while in other embodiments, a single flexure is used to restrict the horizontal movement of the plunger assembly 234, generally with less torsional constraint.

[0028] The flexures 208 and 222 are compliant mechanisms that require relatively little force to deflect in the direction of operation (i.e., along the central longitudinal axis 238), but require a much larger amount of force to deflect in any other direction. As will be discussed further below, the flexures 208 and 222 may represent different parts of the same flexure that flexibly connect the stator assembly 232 and the plunger assembly 234. This property greatly restricts the plunger assembly 234 to follow the same path through the center of the stator assembly 232 during all operation. This property also greatly or completely eliminates friction between the stator assembly 232 and the plunger assembly 234 and limits the rotation of the plunger assembly 234 inside the chamber 236 of the stator assembly 232. In the embodiment shown in Figure 2A, the flexures 208, 222, which again may represent different components of a single flexure, can apply a “biasing force” to the plunger assembly 234 in either direction, and the “biasing force” allows for a higher initial acting force (and consequently, faster displacement) during operation. Generally, the flexures 208, 222 are made of metal, metal alloy, or polymer.

[0029] As shown in Figure 2A, the stator assembly may include a series of ferromagnetic layers with coils positioned between them. During operation, current is applied to the coils, magnetically polarizing the series of ferromagnetic layers as will be discussed further below. In the embodiment shown in Figure 2A, the stator assembly 232 includes a triad of ferromagnetic layers, namely a first ferromagnetic layer 210 (also called the “bottom ferromagnetic layer”), a second ferromagnetic layer 214 (also called the “intermediate ferromagnetic layer”), and a third ferromagnetic layer 216 (also called the “top ferromagnetic layer”). Generally, the bottom and intermediate ferromagnetic layers 210, 214 may extend circumferentially around the chamber 236 and thus have an annular shape. On the other hand, the top ferromagnetic layer 216 may extend across the entire width of the stator assembly 232 such that its bottom surface defines the upper end of the chamber 236. The upper ferromagnetic layer 216 shown in Figure 2A has a disk shape, but the upper ferromagnetic layer 216, like the intermediate and bottom ferromagnetic layers 214, 210, may have an annular shape. In such embodiments, an opening in the upper ferromagnetic layer 216 may allow observation and / or measurement of the motion of the plunger assembly 234 and / or connection of additional loads on the plunger. It should be noted that the opening may be sized so that its diameter is smaller than the diameter of the upper ferromagnetic plate 230, so as to ensure that the plunger assembly 234 remains fully confined within the chamber of the stator assembly 232.

[0030] The bottom, middle, and top ferromagnetic layers 210, 214, and 216 are generally only the thickness necessary to prevent magnetic saturation while the plunger assembly 234 is operating within the chamber 236 of the stator assembly 232. Generally, the thickness of the bottom, middle, and top ferromagnetic layers 210, 214, and 216 is 0.4 mm or less (preferably 0.3 mm). Most of the other layers included within the stator assembly 232 are less constrained and may therefore be determined based on the intended application of the electromechanical device 200. For example, the thickness of the "coil stack" may vary depending on the number of coils, and the thickness of the spacer 206 may depend on the plunger assembly 234, since the bottom portion of the plunger assembly 234 must be able to move within the chamber 236, i.e., between the upper surface of the load stop portion 204A-B and the bottom surface of the bottom ferromagnetic layer 210. The load stop portion 204A-B is the surface with which it and the load come into contact at the "closed" end of its stroke. The load stoppers 204A-B may serve different purposes depending on the device in which the actuator is incorporated. For example, in a relay, the load stoppers 204A-B may be conductive elements that are short-circuited together with the load 218 when the load 218 is in the closed position. In a MEMS valve, the load stoppers 204A-B (or a single load stopper) may be the valve seat. In this situation, the load 218 will be the valve itself, sealing against the valve seat in the closed position. Therefore, the load stoppers 204A-B are shown in Figure 2A to illustrate the surface with which the plunger contacts. Note that various intermediate layers (e.g., flexures and spacers) are not shown in Figure 2A for the sake of simplification. These various intermediate layers generally have a thickness of 25 to 375 micrometers (μm) and a width of 1.5 to 6 mm. Generally, all the layers shown in Figure 2A have a thickness of 25–375 μm and a width of 1.5–6 mm, although the dimensions may depend on the intended application of the electromechanical actuator 200.

[0031] One or more coils can be positioned between each set of ferromagnetic layers. In the embodiment shown in Figure 2A, for example, a first set of coils is positioned between the bottom ferromagnetic layer 210 and the intermediate ferromagnetic layer 214, while a second set of coils is positioned between the intermediate ferromagnetic layer 214 and the upper ferromagnetic layer 216. Such a design results in the bottom ferromagnetic layer 210 being positioned adjacent to the load stop section 204A-B, the first set of coils being positioned adjacent to the bottom ferromagnetic layer 210, the intermediate ferromagnetic layer 214 being positioned adjacent to the first set of coils, the second set of coils being positioned adjacent to the intermediate ferromagnetic layer 214, and the upper ferromagnetic layer 216 being positioned adjacent to the second set of coils. Note that the term “adjacent” as used herein can generally be used to refer to the spatial relationship between two components. A first component may be “adjacent” to a second component without individual sides being adjacent to each other. Therefore, one or more intermediate components may exist between components that are "adjacent" to each other. Conversely, the term "directly adjacent" is generally used to refer to components that are adjacent to each other without any intermediate components between them, except for adhesives or other materials that may be required to join them together.

[0032] In the embodiment shown in Figure 2A, the first plurality of coils includes a pair of coils 212A-B, while the second plurality of coils also includes a pair of coils 212C-D. Although the first and second plurality of coils include the same number of coils in Figure 2A, they may include different numbers of coils. For example, a single coil may be positioned between a pair of ferromagnetic layers. The required number of coils may depend on the force required to operate assuming a latching force, the desired drive voltage and current, and the acceleration required to satisfy the desired open time requirements and / or closed time requirements.

[0033] During operation, current is applied to coils 212A-D, as will be further discussed below. When this occurs, coils 212A-D produce magnetic fields in opposite directions such that the bottom, middle, and top ferromagnetic layers 210, 214, and 216 in the stator assembly 232 have inner poles in a north-south-north ("NSN") configuration or a south-north-south ("SNS") configuration from top to bottom, depending on the direction of the current. Note that the term "inner pole" is used to describe the radial end of each ferromagnetic layer located in the nearest neighbor of the plunger assembly 234. Since the plunger assembly 234 has two fixed poles (i.e., either a north-south configuration or a south-north configuration, which is defined during the manufacture of the plunger assembly 234 by the orientation of the permanent magnet 228), all adjacent poles between the stator assembly 232 and the plunger assembly 234 will push or pull in the same direction, and reversing the direction of the current will reverse the direction in which the stator assembly 232 and the plunger assembly 234 are pushed or pulled.

[0034] The plunger assembly 234 is located within the chamber 236 of the stator assembly 232 and represents another group of layers that move along the central longitudinal axis 238 between a first position and a second position during operation.

[0035] As mentioned above, the stator assembly 232 and the plunger assembly 234 can be connected to each other by one or more flexible sections. In the embodiment shown in Figure 2A, schematic features 208 and 222 represent different regions of a single flexible section layer. Thus, the inner flexible section region 222 may be directly connected to the outer flexible section region 208, and the inner flexible section region 222 may move vertically with the plunger assembly 234 due to the elastic deformation of the flexible section layer, while the outer flexible section region 208 may remain static, i.e., embedded within the layer of the stator assembly 232, despite being connected to the inner flexible section region 222. The flexible sections may be designed to allow vertical displacements in the range of 0-25 microns, 25-100 microns, 100-150 microns, 150-200 microns, 200-250 microns, or above 250 microns. The flexible sections can have various forms. For example, the flexure portion may be in the form of a disk with a circular ring, or the flexure portion may have a central circular portion connected by three flexible interconnected sections (also called "arms") and a hexagonal ring. In Figure 2A, the outer flexure region 208 is the hexagonal ring, while the inner flexure region 222 is the central circular portion. Thus, the outer flexure region 208 and the inner flexure region 222 are part of the same layer. In embodiments in which the electromechanical device 200 includes multiple flexure portions, the flexure portions may be arranged at different heights along a "stack". Having multiple flexure portions will provide better (i.e., stiffer) angular control of the motion of the plunger assembly 234 and will prevent the plunger assembly 234 from "tilting" when it moves vertically. Additional flexure portions may also allow stress to be distributed among them, enabling a longer fatigue life and / or additional material options.

[0036] As shown in Figure 2A, the spacer 224 may be positioned along the upper surface of the flexure 222 such that the bottom portion of the spacer 224 is horizontally aligned with the bottom ferromagnetic layer 210 of the stator assembly 232 when the plunger assembly 234 is in a first position. When the plunger assembly 234 is in a second position, the upper portion of the spacer 224 may be horizontally aligned with the bottom ferromagnetic layer 210 of the stator assembly 232. Generally speaking, the thickness of the spacer 224 may be selected to accommodate the controlled movement of the plunger assembly 234.

[0037] A plunger element (or simply "plunger") can be positioned along the upper surface of the spacer 224. The plunger element may include a permanent magnet 228 to which ferromagnetic plates are bonded, laminated, or otherwise fixed along its upper and bottom poles. Specifically, a bottom ferromagnetic plate 226 may be connected along the bottom pole of the permanent magnet 228, and an upper ferromagnetic plate 230 may be connected along the upper pole of the permanent magnet 228. As shown in Figure 2A, the bottom ferromagnetic plate 226 and the upper ferromagnetic plate 230 can be seated between the ferromagnetic layers in the stator assembly 232. Specifically, the bottom ferromagnetic plate 226 may be positioned between the bottom ferromagnetic layer 210 and the intermediate ferromagnetic layer 214, while the upper ferromagnetic plate 230 may be positioned between the intermediate ferromagnetic layer 214 and the upper ferromagnetic layer 216. During operation, the upper ferromagnetic plate 230 and the lower ferromagnetic plate 226 provide a low magnetoresistance path for the magnetic field generated by the coils 212A-D to follow, thereby enabling the permanent magnet 228 to be coupled to the lower ferromagnetic layer 210, the intermediate ferromagnetic layer 214, and the upper ferromagnetic layer 216.

[0038] Therefore, the plunger assembly 234 may include (i) a load 218 which is an actuator-driven component that performs a certain function when moved, (ii) a flexible portion 222 for controlling vertical movement along the central longitudinal axis 238, (iii) a spacer 224, and (iv) a permanent magnet 228 to which an upper ferromagnetic plate 230 and a bottom ferromagnetic plate 226 are fixed along its poles. The upper ferromagnetic plate 230 may be positioned between the upper ferromagnetic layer 216 and the intermediate ferromagnetic layer 214 of the stator assembly 232, while the bottom ferromagnetic plate 226 may be positioned between the intermediate ferromagnetic layer 214 and the bottom ferromagnetic layer 210.

[0039] The thickness of the permanent magnet 228 is generally maximized, both mechanically and magnetically, within the constraints set by the application of the surrounding layers and the electromechanical actuator 200. For example, the magnet thickness may be selected so as not to exceed the saturation magnetic flux density of the ferromagnetic plates 226 and 230. Similarly, the magnet thickness may also be selected so that the total magnetic flux is sufficient to produce a proper latching force for the intended application of a particular embodiment. Mechanical constraints on the magnet thickness may include ensuring that the vertical distance between the top surface of the bottom ferromagnetic plate 226 and the bottom surface of the upper ferromagnetic plate 230 does not exceed the difference between the thickness of the intermediate ferromagnetic layer 214 and the intended stroke length. The thickness of the permanent magnet 228 may typically be sized such that the upper ferromagnetic plate 230 contacts the upper ferromagnetic layer 216 while the bottom ferromagnetic plate 226 touches the intermediate ferromagnetic layer 214 at the top of the stroke, and the upper ferromagnetic plate 230 contacts the intermediate ferromagnetic layer 214 while the bottom ferromagnetic plate 226 touches the bottom ferromagnetic layer 210 at the bottom of the stroke (i.e., the gap is equal on both sides). This may tend to maximize the magnetic force in both latching and acting by minimizing the gap in the magnetic circuit at both ends of the stroke.

[0040] Similar to the stator assembly 232, the dimensions of the layers within the plunger assembly 234 are generally unconstrained and may therefore be determined based on the intended application of the electromechanical actuator 200. However, the permanent magnet 228, the bottom ferromagnetic plate 226, and the top ferromagnetic plate 230 may be designed with the stator assembly 232 in mind. For example, the permanent magnet 228, the bottom ferromagnetic plate 226, and the top ferromagnetic plate 230 should be designed such that (i) the top ferromagnetic plate 230 is able to move within the gap between the top surface of the intermediate ferromagnetic layer 214 and the bottom surface of the top ferromagnetic layer 216, and (ii) the bottom ferromagnetic plate 226 is able to move within the gap between the top surface of the bottom ferromagnetic layer 210 and the bottom surface of the intermediate ferromagnetic layer 214.

[0041] As can be seen in Figures 2A-C, the chamber 236 may not be purely cylindrical. Instead, the layers of the stator assembly 232 and / or plunger assembly 234 may be sized and arranged such that the chamber 236 has structural features along its longitudinal side that allow for improved control of the plunger assembly 234. For example, consider the embodiment shown in Figure 2A. In this embodiment, the upper ferromagnetic layer 216 extends across the entire circumference of the stator assembly 232. The intermediate ferromagnetic layer 214 and the bottom ferromagnetic layer 210, on the other hand, have the form of annular cylinders (also called “coaxial cylinders”), with a central opening corresponding to the chamber 236. These annular cylinders are defined by an inner radius extending from the central longitudinal axis 238 to the inner circumference and an outer radius extending from the central longitudinal axis 238 to the outer circumference. Similarly, each “coil stack” may have the form of an annular cylinder. However, the inner radius of the "coil stack" may not be the same as the inner radius of the intermediate ferromagnetic layer 214 and the bottom ferromagnetic layer 210. When the inner radius of the "coil stack" is larger than the inner radii of the intermediate ferromagnetic layer 214 and the bottom ferromagnetic layer 210, structural features generally called "notches" or "shelf sections" are formed, and these structural features can accommodate the upper ferromagnetic plate 230 and the bottom ferromagnetic plate 226, as discussed above.

[0042] Overview of the operating principle As mentioned above, the electromechanical actuator 200 can be driven by applying a fixed pulse current through coils 212A-D.

[0043] To move the plunger assembly 234 from a first position to a second position, current is applied to coils 212A-D such that the current flows in a first direction. When the plunger assembly 234 moves from the first position to the second position, downward movement may be hindered by any of the following: (i) mechanical resistance of the flexures 208, 222; (ii) the upper ferromagnetic plate 230 contacting the upper surface of the intermediate ferromagnetic layer 214; (iii) the bottom ferromagnetic plate 226 contacting the upper surface of the bottom ferromagnetic layer 210; or (iv) the load 218 contacting its components at the end of its stroke.

[0044] To move the plunger assembly 234 from a second position to a first position, current is applied to coils 212A-D such that the current flows in a second direction opposite to the first direction. When the plunger assembly 234 moves from the second position to the first position, upward movement may be hindered by (i) the mechanical resistance of the outer flexure region 208 and the inner flexure region 222, (ii) the upper ferromagnetic plate 230 contacting the bottom surface of the upper ferromagnetic layer 216, or (iii) the bottom ferromagnetic plate 226 contacting the bottom surface of the intermediate ferromagnetic layer 214. Thus, upward movement may be hindered by the flexure reaching its limit of expansion so that its restoring force prevents further axial movement, or upward movement may be hindered by the upper ferromagnetic layer 230 or the intermediate ferromagnetic layer acting as a physical barrier.

[0045] Therefore, in order to actuate the plunger assembly 234, a fixed pulse current obtained from a power source (not shown) can be applied to the coils 212A-D of the stator assembly 232, such action magnetically polarizes the upper ferromagnetic layer 216, the intermediate ferromagnetic layer 214, and the bottom ferromagnetic layer 210. A positive current can move the plunger assembly 234 to a first position, thereby moving the load 218 to the "open" position. Conversely, a negative current can move the actuator assembly 234 to a second position, thereby moving the load 218 to the "closed" position. Figure 3 includes a simplified schematic illustration of the latching behavior of the electromechanical actuator caused by the magnetic circuits in the "open" and "closed" positions. In Figure 3, dashed lines indicate magnetic flux in one magnetic circuit, while dotted lines indicate magnetic flux in another magnetic circuit. A magnetic flux in one direction, indicated by a dashed line, "opens" the electromechanical actuator, while a magnetic flux in the opposite direction, indicated by a dotted line, "closes" the electromechanical actuator. Note that Figure 3 shows a portion of the plunger assembly.

[0046] The load 218 may be described as being in an “open” position or a “closed” position, but it should be noted that a person skilled in the art will recognize that these positions may simply be opposite end positions. Thus, the “open” position may also be called the “first end position” or simply the “first position,” while the “closed” position may also be called the “second end position” or simply the “second position.”

[0047] A. Magnetic latch A crucial aspect of electromechanical actuators is their approach to operation. Conventional electromechanical actuators may require a continuous current to be applied to maintain a given state (e.g., closed state). To avoid requiring a continuous current to remain open or closed, electromechanical actuators can instead be designed to "latch" into a fixed position whenever the state is switched. This is achieved by designing the actuator to be magnetically bistable.

[0048] Referring to Figure 2A, the spacing between the upper ferromagnetic layer 216, the intermediate ferromagnetic layer 214, and the bottom ferromagnetic layer 210 in the stator assembly 232 can be matched to the spacing between the upper ferromagnetic plate 230 and the bottom ferromagnetic plate 226 (and the permanent magnets 228 and spacers 224) of the plunger assembly 234. The distance that the magnetic field lines generated by coils 212A-D travel through the non-ferrous material is minimized when the plunger is at its highest and lowest positions, and this effect is maximized when the spacing is matched. This generates two minimums of magnetoresistance (and therefore potential energy) at these positions, causing the plunger to "latch" at its highest and lowest positions, and the magnetic "latching force" is maximized when the spacing is matched.

[0049] The size of the permanent magnet 228, the thickness of the upper ferromagnetic plate 230 and the bottom ferromagnetic plate 226, the vertical spring constants of the outer flexure region 208 and the inner flexure region 222, and the distance between the highest and lowest positions can affect the latching force. To maximize the operating speed, the net latching force (including magnetic and flexure contributions) can be minimized within the constraints set by vibration and shock resistance. Since the operating force, which should be maximized to optimize the switching speed, is determined primarily based on the sum of the magnetic latching force and the vertical flexure force, the geometry of the flexure tends to be the parameter that is easiest to manipulate. Therefore, selecting the flexure spring constant to set the “net latching force” to an appropriate value is typically preferable to redesigning or re-selecting the permanent magnet 228 or the upper ferromagnetic plate 230 and the bottom ferromagnetic plate 226, or using a larger distance (also called “gap size”).

[0050] B. Magnetic operation Figure 4 includes a schematic illustration showing how the current passing through coils 406A-N and 410A-N would result in a constant magnetic force being applied to plunger 402. To better illustrate the magnetic force, the electromechanical actuator 400 is “decomposed” so that the various layers are separated and “enlarged” so that the various layers are not drawn to scale.

[0051] As discussed above, the stator assembly 420 may include a set of three ferromagnetic layers, the set of three ferromagnetic layers having coils positioned between them, so that (i) at least one coil is positioned between the bottom ferromagnetic layer 404 and the intermediate ferromagnetic layer 408, and (ii) at least one coil is positioned between the intermediate ferromagnetic layer 408 and the upper ferromagnetic layer 412. For example, a set of coils 406A-N may be positioned between the bottom ferromagnetic layer 404 and the intermediate ferromagnetic layer 408, and another set of coils 410A-N may be positioned between the intermediate ferromagnetic layer 408 and the upper ferromagnetic layer 412. The first and second sets of coils 406A-N, 410A-N may include the same number of coils, or the first and second sets of coils 406A-N, 410A-N may include different numbers of coils. Typically, each of the coils 406A-N, 410A-N contains at least two coils, but any number of coils can be positioned between the bottom ferromagnetic layer 404 and the intermediate ferromagnetic layer 408, or between the intermediate ferromagnetic layer 408 and the upper ferromagnetic layer 412. The thickness of each "coil stack" may depend, for example, on the size of the plunger 402. The thickness of each "coil stack" tends to be proportional to the number of coils it contains.

[0052] As shown in Figure 3, only the plunger 402 of the operating assembly is shown in Figure 4. The plunger 402 may include a permanent magnet 414, to which ferromagnetic plates 416, 418 are fixed along its upper and lower poles. Here, for example, the lower ferromagnetic plate 416 is connected along the lower pole (i.e., the south pole) of the permanent magnet 414, and the upper ferromagnetic plate 418 is connected along the upper pole (i.e., the north pole) of the permanent magnet 414.

[0053] The upper ferromagnetic layer 412, the intermediate ferromagnetic layer 408, and the bottom ferromagnetic layer 404 can be sandwiched between the upper ferromagnetic plate 416 and the bottom ferromagnetic plate 418, as shown in Figure 4. The upper ferromagnetic plate 418 can be positioned between the upper ferromagnetic layer 412 and the intermediate ferromagnetic layer 408, and the bottom ferromagnetic plate 416 can be positioned between the intermediate ferromagnetic layer 408 and the bottom ferromagnetic layer 404.

[0054] As mentioned above, the current passing through coils 406A-N and 410A-N causes a constant magnetic force to be applied to the plunger 402 (more specifically, to the upper ferromagnetic plate 418 and the lower ferromagnetic plate 416). This constant magnetic force is generally proportional to the current and the number of turns in coils 406A-N and 410A-N. Once this constant magnetic force overcomes the "latching force" of the plunger 402 (more specifically, the permanent magnet 414), the plunger 402 will begin to move downward (for example, towards the lower ferromagnetic layer 404) or upward (for example, towards the upper ferromagnetic layer 412).

[0055] By applying a positive current to coils 406A-N and 410A-N, movement in one direction (e.g., upward) can be achieved. Applying a negative current to coils 406A-N and 410A-N can result in movement in the other direction (e.g., downward). For example, a positive current can move the plunger 402 upward until the upper ferromagnetic plate 418 contacts the bottom surface of the upper ferromagnetic layer 412 and / or the bottom ferromagnetic plate 416 contacts the bottom surface of the intermediate ferromagnetic layer 408. When the plunger 402 is in this position, the electromechanical actuator 400 can be described as "open". Conversely, a negative current can move the plunger 402 downward until the upper ferromagnetic plate 418 contacts the top surface of the intermediate ferromagnetic layer 408 and / or the bottom ferromagnetic plate 416 contacts the top surface of the bottom ferromagnetic layer 404. When the plunger 402 is in this position, the electromechanical actuator 400 can be described as "closed".

[0056] Various parameters can affect this constant magnetic force, as well as the speed at which the plunger 402 can move between positions. These parameters include the following: • Thickness and composition of the upper ferromagnetic layer 412, the intermediate ferromagnetic layer 408, and the bottom ferromagnetic layer 404 For example, the thickness of the upper ferromagnetic layer, the intermediate ferromagnetic layer, and the bottom ferromagnetic layer may be 25 to 325 μm. • Thickness and grade of permanent magnet 414 For example, the thickness of the permanent magnet 414 may be 0.2 to 0.5 mm. • Number of turns for coils 406A-N and 410A-N • Magnitude of the current applied to coils 406A-N and 410A-N • Diameters of coils 406A-N, 410A-N, and permanent magnet 414 • Because spatial relationships affect the direction of the magnetic field gradient, the spacing between the upper ferromagnetic layer 412, the intermediate ferromagnetic layer 408, and the bottom ferromagnetic layer 404, and the overlap between the upper ferromagnetic layer 412, the intermediate ferromagnetic layer 408, and the bottom ferromagnetic layer 404

[0057] During operation, current is applied to coils 406A-N and 410A-N. When this occurs, coils 406A-N and 410A-N produce magnetic fields in opposite directions to induce poles in the upper ferromagnetic layer 412, the intermediate ferromagnetic layer 408, and the bottom ferromagnetic layer 404. Depending on the direction of the current, the inner poles of the upper ferromagnetic layer 412, the intermediate ferromagnetic layer 408, and the bottom ferromagnetic layer 404 may be in an NSN configuration or an SNS configuration. The permanent magnet 414 has two fixed poles. Here, for example, the permanent magnet has an NS configuration. Thus, when the upper ferromagnetic layer 412, the intermediate ferromagnetic layer 408, and the bottom ferromagnetic layer 404 are magnetically polarized, all the inner poles of the stator assembly 420 will push or pull the plunger 402 in the same direction. Reversing the direction of the current would reverse the direction in which the inner poles of the stator assembly 420 push or pull the plunger 402. Figure 4 illustrates how applying current to coils 406A-N and 410A-N can induce magnetic polarization that applies a magnetic force to the plunger 402.

[0058] Figures 5A–E include visualizations illustrating the magnetic field strength and direction as the plunger assembly is moved between a first and a second position. Specifically, Figure 5A illustrates the plunger assembly in the first position. To move the plunger assembly to the second position, a fixed pulse of positive current can be applied to the coil to magnetically attract the plunger assembly downward. Figure 5B illustrates the plunger assembly as it is moving toward the second position, while Figure 5C illustrates the plunger assembly in the second position. To move the plunger assembly back to the first position, a fixed pulse of negative current can be applied to the coil to magnetically attract the plunger assembly upward. Figure 5D illustrates the plunger assembly as it is moving toward the first position, while Figure 5E illustrates the plunger assembly returning to the first position.

[0059] C. Constrained motion and flexibility Flexible sections (e.g., flexible sections 208 and 222 in Figure 2A) can be used to keep the plunger assembly centered within the chamber of the stator assembly to ensure that the movement is, if not perfectly, primarily perpendicular along the central longitudinal axis. Furthermore, these flexible sections can suppress or prevent friction between the various layers of the plunger assembly and the stator assembly. To accomplish this, the flexible sections may need to have a stiffness against lateral motion of at least the maximum lateral magnetic force divided by the worst-case clearance within the manufacturing tolerance, assuming the worst-case geometry within the manufacturing tolerance.

[0060] To ensure that the load (e.g., load 218 in Figure 2A) can seat flat along the upper surface of the load-stopping section (e.g., load-stopping section 204A-B in Figure 2A), the maximum lateral asymmetry in the flexural force can be less than the remaining closing latch force after considering any force applied by the flexural section.

[0061] Figure 6 includes a perspective cross-sectional view illustrating how a flexible portion 602 connected to the plunger assembly 604 can restrict the movement of the plunger assembly 604 relative to the stator assembly 606. To ensure that the flexible portion 602 is properly positioned, it may be "sandwiched" between layers in the plunger assembly 604 and / or the stator assembly 606. For example, the flexible portion 602 may be interposed between ceramic layers.

[0062] For simplicity, only some components of the plunger assembly 604 and stator assembly 606 are shown in Figure 6. Specifically, Figure 6 shows how the flexure 602 can ensure that the movement of the load 608 is substantially vertical or longitudinal, i.e., along the longitudinal axis 610. Some degree of inclination may occur, but the plunger assembly 604 will not be subjected to any meaningful horizontal or lateral movement, nor will the plunger assembly 604 be subjected to any meaningful rotation about the longitudinal axis.

[0063] As can be seen in Figure 6, such an approach to guiding the movement of the plunger assembly 604 not only allows for repeated movement with a high degree of agreement, but also avoids any friction from the plunger assembly 604 contacting the inner wall of the stator assembly 606. This friction can lead to poor and / or unreliable performance, and therefore, avoiding this friction is important.

[0064] Packaging and internal environment Embodiments of electromechanical actuators can benefit from being sealed to prevent fluids (e.g., gases and liquids) from entering or leaving the chamber of the stator assembly from the ambient environment.

[0065] In addition to being sealed, embodiments of electromechanical actuators may have an insulating fluid that can be left empty or deposited or injected therein. For example, a chamber defined within a stator assembly may be filled with a chemically inert electroinsulating gas at a pressure above or below 1 atmosphere, or the chamber may be filled with a chemically inert electroinsulating liquid at a pressure above or below 1 atmosphere. When used in an electromechanical relay, the chamber may be filled with an insulating fluid to provide sufficient dielectric standoff with respect to a given stroke length of the plunger assembly. Having atmospheric pressure above 1 atmosphere would also result in a pressure bias being applied across any leakage paths through the sealed envelope, thereby suppressing or preventing the entry of air into the chamber. The liquid in the chamber may be electrically insulating or conductive, depending on the application. The liquid may serve as a means of transmitting liquid pressure or provide dielectric breakdown resistance.

[0066] Generally, insulating fluids are chemically inert electrical insulating gases consisting entirely or primarily of nitrogen. However, nitrogen may be mixed with one or more other electrical insulating gases to improve arc resistance, for example (so that it may be useful for electromechanical relays). However, other fluids may also be used. For example, the insulating fluid may be another chemically inert electrical insulating gas such as argon, or the insulating fluid may be a chemically inert electrical insulating liquid such as hexamethyldisiloxane or octamethyltrisiloxane, which are low molecular weight, low viscosity silicones.

[0067] Design Selection Since the actuation force is proportional to acceleration, the total initial force at the start of the "stroke" disproportionately determines the time required to switch from one state to another. Note that the total initial force can be broadly characterized by the sum of the latching force, actuation force, and flexural force. To maximize the force at the start of the "stroke," the flexural part can be used like a spring to counteract the latching force. If the latching force is partially, if not completely, counteracted, the total initial force can instead be characterized by the sum of the actuation force and flexural force.

[0068] Approach to the design and manufacture of electromechanical actuators For designing an electromechanical actuator according to the embodiments disclosed herein, it is most convenient to consider the electromechanical actuator as a combination of two components: (i) a stator assembly having a chamber partially defined therethrough along a central longitudinal axis, and (ii) a plunger assembly positioned within the chamber of the stator assembly and moving along the central longitudinal axis between a first position and a second position during operation. Generally speaking, the stator assembly includes two partial components: (i) a contact assembly and (ii) a drive electromagnetic assembly. Figure 7 includes schematic illustrations of the plunger assembly 702 of the stator assembly 704 and the stator assembly 708. As discussed above, the stator assembly 708 facilitates the operation of the plunger assembly 702 by generating a magnetic field when current is applied thereto. The operation of the plunger assembly 702 results in its bottom surface either engaging with or disengaging from the load stop 706.

[0069] The machining of the electromechanical actuator requires the separate machining of its partial components. Figure 8 includes an illustration of a set of steps that may be used to assemble the relay 200 as a group of layers. Note that, for convenience, components discussed with reference to Figure 2A may be referenced. The order of assembly is important because the flexural layers, represented by flexural regions 208 and 222, which are part of the same flexural section, are contained within both subassemblies. Furthermore, since the plunger assembly 234 cannot be inserted through the opening in the intermediate ferromagnetic layer 214 after it has been assembled, the interlocking sides of the ferromagnetic layers require that the plunger assembly be assembled in position. For illustrative purposes, one possible order of assembly, as illustrated in Figure 8, is as follows:

[0070] Step 1: Start with spacer 1, which is rigidly connected between plunger assembly 234 and stator assembly 232 by a removable tab marked with an "X".

[0071] Step 2: Load 2 is stacked on spacer 1.

[0072] Step 3: The bottom ferromagnetic layer 210 is laminated onto the assembly produced in Step 2.

[0073] Step 4: The spacer 224, bottom ferromagnetic plate 226, and magnet 228 of the plunger assembly 234 are stacked in the opening left inside the bottom ferromagnetic layer 210.

[0074] Step 5: The first set of coils 212A-B and the intermediate ferromagnetic layer 214 are laminated onto the assembly produced in Step 4.

[0075] Step 6: The upper ferromagnetic plate 230 is stacked on top of the magnet 228.

[0076] Step 7: A second set of coils 212C-D and the upper ferromagnetic layer 216 are laminated on top of the assembly produced in Step 6.

[0077] Step 8: The spacer layer 206 is stacked on the bottom of the assembly produced in Step 7. The tabs (×) applied in Step 1 are then removed, freeing the movement of the plunger assembly 234 such that it is constrained by the flexures represented collectively by 208 and 222.

[0078] Step 9: The assembly produced in Step 8 is placed on top of the load stopper 204A-B. The load stopper 204A-B may be stacked or clamped in a fixed position below the assembly.

[0079] Those skilled in the art will recognize that other assembly sequences are also possible and may be desirable in some embodiments, depending on the speed or precision to which the electromechanical actuator 200 should be assembled.

[0080] Figure 9 includes a high-level diagram of process 900 for fabricating an electromechanical actuator. Again, for convenience, components discussed with reference to Figure 2A may be referenced. However, Figure 9 is specific to the design of an electromechanical actuator that does not include a flexible section connecting the stator assembly and the plunger assembly. First, the manufacturer may fabricate the upper ferromagnetic layer by cutting a single layer from a piece of ferromagnetic material (e.g., steel) (step 901). The manufacturer may then fabricate the plunger (step 902). For example, the manufacturer may create or obtain a permanent magnet and then layer ferromagnetic plates along its upper and bottom poles. These ferromagnetic plates may be called the “upper ferromagnetic plate” and the “bottom ferromagnetic plate,” respectively. The manufacturer may then fabricate the plunger assembly by laminating, bonding, or otherwise connecting spacers and loads to the bottom ferromagnetic plate (step 903). Note that additional layers may be included within the plunger assembly.

[0081] To fabricate the stator assembly, the manufacturer may obtain a substrate (step 904), bond the components (with which the load interacts) to the upper surface of the substrate (step 905), and then laminate ferromagnetic layers and coils to the upper surface of a pair of contacts in an alternating manner (step 906). Generally, the ferromagnetic layers and coils are laminated such that the resulting electromechanical actuator includes triplicate ferromagnetic layers with one or more coils positioned between the first and second ferromagnetic layers and another one or more coils positioned between the second and third ferromagnetic layers. In some embodiments, the bottommost ferromagnetic layer is laminated directly adjacent to the pair of contacts, while in other embodiments, one or more intervening layers are present, as shown in Figure 2A.

[0082] To create an electromechanical actuator, the manufacturer can position the plunger assembly within a cavity defined through the stator assembly, and then bond the upper ferromagnetic layer to the stator assembly (step 907). Bonding the upper ferromagnetic layer to the stator assembly defines a fully enclosed chamber inside the stator assembly. As discussed above, during operation, the plunger assembly is capable of moving between different positions inside the fully enclosed chamber.

[0083] remarks The foregoing description of various embodiments of the claimed subject matter is provided for illustrative and explanatory purposes only. It is not intended to be exhaustive or to limit the claimed subject matter to the precise form disclosed. Many modifications and variations will be obvious to those skilled in the art. The embodiments have been selected and described to illustrate the principles of the invention and its practical applications in the most detail, thereby enabling those skilled in the art to understand the claimed subject matter, the various embodiments, and the various modifications suitable for specific intended uses.

[0084] While the detailed description illustrates certain embodiments and assumed best modes, the Art can be practiced in many ways, no matter how detailed the detailed description may seem. Embodiments, while still encompassed by this Specification, can vary considerably in their implementation details. Certain technical terms used when describing certain features or aspects of various embodiments should not be taken as implying that the terms are redefined herein to be limited to any specific characteristic, feature, or aspect of the Art to which the terms relate. In general, terms used in the following claims should not be construed as limiting the Art to the specific embodiments disclosed herein unless those terms are expressly defined herein. Thus, the actual scope of the Art encompasses not only the disclosed embodiments but also all equivalent methods of practicing or implementing those embodiments.

[0085] The language used herein has been selected primarily for readability and instructional purposes. It may not have been selected to delineate or limit the subject matter. Therefore, the scope of this Art is not intended to be limited by this detailed description, but rather by any claims issued relating to the uses described herein. Accordingly, the disclosure of various embodiments is intended to be illustrative rather than limiting the scope of this Art as set forth in the following claims.

[0086] This application claims the benefit of priority from U.S. Application No. 63 / 497,361, filed on April 20, 2023, which is incorporated herein by reference in its entirety.

Claims

1. An electromechanical actuator, A stator assembly, the stator assembly having a chamber partially defined therethrough along a central longitudinal axis, The stator assembly is, A nonconductive substrate having an upper surface, A layer or a plurality of layers containing a component, wherein the load interacts mechanically or electrically with the component and the layer or a plurality of layers. A first ferromagnetic layer adjacent to the spacer, A plurality of first coils adjacent to the first ferromagnetic layer, A second ferromagnetic layer adjacent to the first plurality of coils, A second set of coils adjacent to the second ferromagnetic layer, A third ferromagnetic layer adjacent to the second plurality of coils, wherein the bottom surface of the third ferromagnetic layer is defined by the upper end of the chamber, and including, Stator assembly and A plunger assembly positioned within the chamber of the stator assembly, which moves along the central longitudinal axis between a first position and a second position during operation, The plunger assembly is A plunger comprising a pair of ferromagnetic plates, with a magnet positioned between them, (i) The first ferromagnetic plate of the pair of ferromagnetic plates is positioned between the first ferromagnetic layer and the second ferromagnetic layer, and (ii) The second ferromagnetic plate of the pair of ferromagnetic plates is positioned between the second ferromagnetic layer and the third ferromagnetic layer. Including plungers, Plunger assembly and An electromechanical actuator equipped with the following features.

2. The electromechanical actuator according to claim 1, wherein when the plunger assembly is in the first position, the lower opening of the plunger assembly is naturally filled with insulating gas.

3. The electromechanical actuator according to claim 1, wherein a current is applied to the first and second coils such that the current flows in a first direction in order to move the plunger assembly from the first position to the second position.

4. When the plunger assembly moves from the first position to the second position, the movement is as follows: (i) The first ferromagnetic plate is in contact with the upper surface of the first ferromagnetic layer, or (ii) The second ferromagnetic plate is in contact with the upper surface of the second ferromagnetic layer. The electromechanical actuator according to claim 1, which is obstructed by...

5. The electromechanical actuator according to claim 4, wherein a current is applied to the first and second plurality of coils such that the current flows in a second direction opposite to the first direction in order to move the plunger assembly from the second position to the first position.

6. When the plunger assembly moves from the second position to the first position, the movement is as follows: (i) The bending portion reaches its limit of expansion, and as a result, the restoring force prevents further axial movement. (ii) The first ferromagnetic plate is in contact with the bottom surface of the second ferromagnetic layer, or (iii) The second ferromagnetic plate is in contact with the bottom surface of the third ferromagnetic layer. An electromechanical actuator according to claim 1, which is interrupted by...

7. An electromechanical actuator, A stator assembly, the stator assembly having a chamber partially defined therethrough along a central longitudinal axis, The stator assembly is, A set of three ferromagnetic layers, the set of three ferromagnetic layers includes coils positioned between them, and as a result, (i) at least one coil is positioned between the first and second ferromagnetic layers of the set of three ferromagnetic layers, and (ii) at least one coil is positioned between the second and third ferromagnetic layers of the set of three ferromagnetic layers. Stator assembly and A plunger assembly positioned within the chamber of the stator assembly, which moves along the central longitudinal axis between a first position and a second position during operation, The plunger assembly is A plunger comprising a pair of ferromagnetic plates and a magnet positioned between them, Plunger assembly and Equipped with, To move the plunger assembly from the first position to the second position, a current is applied to the coil such that the current flows in the first direction, thereby moving the plunger along the central longitudinal axis toward the pair of contacts. To move the plunger assembly from the second position to the first position, a current is applied to the coil such that the current flows in a second direction opposite to the first direction, thereby moving the plunger along the central longitudinal axis away from the pair of contacts. Electromechanical actuator.

8. (i) The first ferromagnetic plate of the pair of ferromagnetic plates is positioned between the first ferromagnetic layer and the second ferromagnetic layer, and (ii) The second ferromagnetic plate of the pair of ferromagnetic plates is positioned between the second ferromagnetic layer and the third ferromagnetic layer, as described in claim 7.

9. When the plunger assembly moves from the first position to the second position, the movement is as follows: (i) The first ferromagnetic plate is in contact with the upper surface of the first ferromagnetic layer, or (ii) The second ferromagnetic plate is in contact with the upper surface of the second ferromagnetic layer. It was hindered by, When the plunger assembly moves from the second position to the first position, the movement is as follows: (i) The first ferromagnetic plate is in contact with the bottom surface of the second ferromagnetic layer, or (ii) The second ferromagnetic plate is in contact with the bottom surface of the third ferromagnetic layer. It is hindered by The electromechanical actuator according to claim 8.

10. The electromechanical actuator according to claim 7, wherein the pair of ferromagnetic plates are stacked along the upper and bottom poles of the magnet.

11. The electromechanical actuator according to claim 7, wherein a plurality of first coils are positioned between the first ferromagnetic layer and the second ferromagnetic layer, and a plurality of second coils are positioned between the second ferromagnetic layer and the third ferromagnetic layer.

12. The electromechanical actuator according to claim 11, wherein the first plurality of coils have the same number of coils as the second plurality of coils.

13. The electromechanical actuator according to claim 7, wherein each of the three ferromagnetic layers has an annular shape so as to completely enclose the chamber.

14. The electromechanical actuator according to claim 7, wherein the amount of current required to move the plunger assembly depends on (i) the thickness of the triple ferromagnetic layer, (ii) the grade and thickness of the magnet, (iii) the number of coil turns, or (iv) the size and thickness of the coil.

15. The electromechanical actuator according to claim 7, wherein the spacing between the three sets of ferromagnetic layers is complementary to the spacing between the pair of ferromagnetic plates, so that when the plunger assembly is positioned at the first and second positions, the distance over which the magnetic field extends through the non-ferrous material is minimized, and as a result, the first and second positions represent a minimum of potential energy.

16. The electromechanical actuator according to claim 7, wherein the chamber is filled with a chemically inert electrical insulating gas at a pressure exceeding 1 atmosphere.

17. The electromechanical actuator according to claim 7, wherein the chamber is filled with a chemically inert electrical insulating gas at a pressure of less than 1 atmosphere.

18. The electromechanical actuator according to claim 7, wherein the chamber is filled with a chemically inert electroinsulating liquid at a pressure exceeding 1 atmosphere.

19. The electromechanical actuator according to claim 7, wherein the chamber is filled with a chemically inert electroinsulating liquid at a pressure of less than 1 atmosphere.

20. An electromechanical actuator, A stator assembly, the stator assembly having a chamber partially defined therethrough along a central longitudinal axis, The stator assembly is, It includes a triple set of ferromagnetic layers with a coil, the coil being positioned between the triple set of ferromagnetic layers and electrically connected to a power source. Stator assembly and A plunger assembly positioned within the chamber of the stator assembly, which moves along the central longitudinal axis between a first position and a second position during operation, The plunger assembly is The device includes a plunger, the plunger including at least one ferromagnetic plate and at least one magnet. Plunger assembly and Equipped with, When an electric current is applied to the coil, the three ferromagnetic layers become magnetically polarized to have either a north-south-north (N-S-N) configuration or a south-north-south (S-N-S) configuration, depending on the direction of the current. The movement of the plunger assembly is determined by the current configuration of the three ferromagnetic layers. Electromechanical actuator.

21. An electromechanical actuator comprising (i) a stator assembly and (ii) a plunger assembly, wherein the layers of the stator and plunger assembly are arranged such that the actuator magnetically latches at each end of its range of motion.

22. An electromechanical actuator, A stator assembly, the stator assembly having a chamber partially defined therethrough along a central longitudinal axis, The stator assembly is, A set of three ferromagnetic layers, the set of three ferromagnetic layers is accompanied by coils positioned between them, and as a result, (i) at least one coil is positioned between the first ferromagnetic layer and the second ferromagnetic layer of the set of three ferromagnetic layers, and (ii) at least one coil is positioned between the second ferromagnetic layer and the third ferromagnetic layer of the set of three ferromagnetic layers, The first part of the flexible section and including, Stator assembly and A plunger assembly positioned within the chamber of the stator assembly, which moves along the central longitudinal axis between a first position and a second position during operation, The plunger assembly is A plunger containing a magnet, The second portion of the aforementioned flexible part and including, Plunger assembly and Equipped with, In order to move the plunger assembly between the first position and the second position, a current is applied to the coil. The second portion is configured to move with the plunger assembly, while the first portion is configured to remain in a fixed position with the stator assembly; therefore, the movement of the plunger assembly is constrained by the flexible portion. Electromechanical actuator.

23. The electromechanical actuator according to claim 22, wherein the flexible portion flexibly connects both the stator assembly and the plunger assembly such that the plunger assembly follows the same path through the chamber during each operation between the first position and the second position.

24. The electromechanical actuator according to claim 22, wherein the flexible portion is designed to suspend the plunger assembly within the chamber such that friction between the plunger assembly and the stator assembly is largely or completely eliminated.

25. The electromechanical actuator according to claim 22, wherein the flexible portion is made of metal, a metal alloy, or a polymer.

26. The electromechanical actuator according to claim 22, wherein the flexural portion is designed to allow vertical displacement of 0 to 25 microns, 25 to 100 microns, 100 to 150 microns, 150 to 200 microns, 200 to 250 microns, or greater than 250 microns.

27. The electromechanical actuator according to claim 22, wherein the flexible portion is in the form of a disk having a circular portion representing the second portion and an annular portion representing the first portion, and the circular portion is connected to the annular portion by a plurality of interconnecting sections configured to be flexible.

28. The electromechanical actuator according to claim 22, wherein the flexible portion is designed to provide the desired axial force when the actuator is latched, such that the axial force provided by the flexible portion counteracts the latching force and enables and assists faster movement of the rotor when current is applied to the coil.

Images