System and method for multi-stable solenoids

Abstract

Systems and methods for a multi-stable solenoid are disclosed. The present disclosure provides a multi-stable solenoid with one or more magnetic dampening rings. Generally, the magnetic dampening rings provide increased dampening force to the armature of the multi-stable solenoid to ensure efficient operation, reduce over-shoot of detent positions, and reduce impact forces at end positions.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based upon and claims priority from U.S. Provisional Patent Application No. 62 / 890,300, filed on August 22, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0003] This application relates to solenoids. Background Art

[0004] Generally, a solenoid may include an armature that is movable in response to an electromagnetic field generated by energizing a coil of wire. Summary of the Invention

[0005] The present disclosure relates generally to solenoids, and more particularly to multistable solenoids having a magnetic damping ring. Typically, the magnetic damping ring provides stability to the solenoid by reducing end stop kick forces or mid-position overshoot as the solenoid's armature travels between stable positions.

[0006] In one aspect, the present disclosure provides a solenoid comprising a wire coil and an armature having a permanent magnet. The armature is movable between two or more stable positions in response to selective energization of the wire coil. The solenoid further comprises one or more magnetic dampers arranged along a travel path of the armature. The one or more magnetic dampers are configured to generate a magnetic damping force in a direction opposite to the movement of the armature.

[0007] In one aspect, the present disclosure provides a solenoid comprising one or more wire coils axially spaced from one another and an armature having a permanent magnet. The armature is movable between stable positions in response to selective energization of one or more of the one or more wire coils. The solenoid further comprises one or more magnetic dampers disposed along a travel path of the armature. The one or more magnetic dampers are configured to generate a magnetic damping force in response to relative movement between the armature and at least one of the one or more magnetic dampers. The direction of the magnetic damping force is opposite to the direction of movement of the armature.

[0008] The foregoing and other aspects and advantages of the present disclosure will become apparent from the following description. In the specification, reference is made to the accompanying drawings which form a part thereof and which illustrate preferred configurations of the present disclosure by way of illustration. Such configurations do not necessarily represent the full scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present application will be better understood in connection with the following detailed description and with reference to the following drawings, of which:

[0010] Figure 1 is a schematic diagram of a conventional multi-stable solenoid according to an aspect of the present disclosure.

[0011] Figure 2 is a schematic diagram of a portion of a multi-stable solenoid of Figure 1 , and a graph showing force as a function of stroke of the solenoid of the multi-stable solenoid with no current applied to the solenoid.

[0012] Figure 3 is a schematic diagram of a portion of a multi-stable solenoid of Figure 1 , and a graph showing force as a function of stroke for a given coil configuration under various firing conditions.

[0013] Figure 4 is a graph showing force as a function of stroke under a given firing condition for the multi-stable solenoid of Figure 1 .

[0014] Figure 5 is a schematic diagram of a multi-stable solenoid including a magnetic damping component according to an aspect of the present disclosure.

[0015] Figure 6 is a graph showing magnetic damping force as a function of stroke with and without a magnetic damping component for various armature speeds.

[0016] Figure 7 is a graph showing armature position as a function of time for a configuration of the solenoid of Figure 6 with and without a damping component. DETAILED DESCRIPTION

[0017] Before any aspects of the disclosure are explained in detail, it is to be understood that the disclosure is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The disclosure is capable of other configurations or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. In this document, "including" "comprising" or "having," and variations thereof, mean encompassing the listed items and their equivalents as well as additional items. Unless specified or limited otherwise, the terms "mounting," "connected," "supported," and "coupled," and variations thereof, are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

[0018] The following discussion is presented to enable a person skilled in the art to make and use aspects of the disclosure. Various modifications to the configurations shown will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other configurations and applications without departing from the aspects of the disclosure. Thus, the aspects of the disclosure are not intended to be limited to the configurations shown, but are to be accorded the widest scope consistent with the principles and features disclosed herein. The following detailed description is to be read with reference to the figures, in which like reference numerals in different figures represent like elements throughout. The figures depict selected configurations and are not necessarily drawn to scale. One skilled in the art will recognize that the illustrative examples provided herein have many useful alternatives and fall within the scope of the present disclosure.

[0019] The term "axial" and variations thereof as used herein refer to a direction that generally extends along a symmetry axis, a center axis, or an elongation direction of a particular component or system. For example, an axially extending structure of a component can generally extend along a direction parallel to a symmetry axis or an elongation direction of the component. Similarly, the term "radial" and variations thereof as used herein refer to a direction that is generally perpendicular to a corresponding axial direction. For example, a radially extending structure of a component can generally extend at least partially along a direction perpendicular to a longitudinal axis or a center axis of the component. The term "circumferential" and variations thereof as used herein refer to a direction that generally extends around a circumference or a periphery of an object, around a symmetry axis, around a center axis, or around an elongation direction of a particular component or system.

[0020] Generally, a multi-stable solenoid can include an armature movable between one or more stable positions. For example, a multi-stable solenoid can define two or more stable positions for the armature. Selective movement of the armature between the stable positions (e.g., a position in which the armature remains in place while the coil is de-energized) can facilitate engagement or disengagement between the armature and one or more end positions. For example, the armature can be movable between two end positions and a center position (i.e., a tri-stable solenoid having three stable positions).

[0021] Conventional multi-stable solenoids often suffer from overshoot when the armature is moved from an end position to a center magnetic detent position. That is, the armature can overshoot and displace beyond the center position, or in some cases, beyond and away from the desired detent position. This overshoot can result in inefficient operation or render the solenoid inoperable in its given application. In some non-limiting examples, a magnetic dampening component can be used to slow and / or reduce the impact force of the armature when it reaches an end position.

[0022] The present disclosure provides systems and methods for dampening or controlling the amount of overshoot when a multi-stable solenoid is moved to a detent position. In some aspects, the present disclosure provides a toroidal solenoid including one or more magnetic dampening components that prevent or limit overshoot travel of the armature when traveling to a detent position. The magnetic dampening components can be toroidal and disposed along the travel path of the armature. In this manner, for example, overshoot beyond the detent position and engagement to an undesirable position can be prevented during operation.

[0023] Figure 1 A non-limiting example of a conventional multi-stable solenoid 100 is shown. In some non-limiting examples, the multi-stable solenoid 100 can be toroidal (i.e., extending circumferentially about a central axis 108).

[0024] In the illustrated, non-limiting example, the multi-stable solenoid 100 can include a housing 116. In some non-limiting examples, the housing 116 can be made of a ferromagnetic material. Generally, the multi-stable solenoid 100 can include a wire coil configured to selectively generate an electromagnetic force in response to an electrical current applied thereto. In some non-limiting examples, the multi-stable solenoid 100 can include a first wire coil 118, a second wire coil 120, a third wire coil 122, and an armature 124. In some non-limiting examples, the first wire coil 118, the second wire coil 120, and the third wire coil 122 can be formed from a single wire coil that is separated into a plurality of coil bays that define the first wire coil 118, the second wire coil 120, and the third wire coil 122. In some non-limiting examples, the first wire coil 118, the second wire coil 120, and the third wire coil 122 can be separate wire coils that are routed separately. In any case, the first wire coil 118, the second wire coil 120, and the third wire coil 122 can be disposed within the housing 116 and can be axially separated (i.e., spaced apart in a direction along the central axis 108), with the second wire coil 120 being axially disposed between the first wire coil 118 and the third wire coil 122. In some non-limiting examples, the multi-stable solenoid can include more or less than three wire coils or coil bays.

[0025] The armature 124 can include a permanent magnet 126 disposed at least partially within the armature 124. In some non-limiting examples, in addition to the permanent magnet 126, the armature 124 can include one or more ferromagnetic components. The armature 124 can be disposed within the housing 116 such that a radial air gap exists between a radial end of the housing 116 and the annular armature 124 (i.e., the radial air gap is defined between an outer diameter of the armature 124 and an inner diameter of the housing 116). In the illustrated, non-limiting example, the permanent magnet 126 can be axially magnetized. That is, the north and south poles of the permanent magnet 126 can be aligned along the central axis 108, or disposed parallel to the central axis 108.

[0026] Reference is made to Figure 2In the illustrated non-limiting example, the armature 124 can be axially movable along the pivot axis 114 between three different stable positions in response to selective activation of one or more of the first wire coil 118, the second wire coil 120, and the third wire coil 122. For example, the armature 124 can be movable between a first end position 128, a center detent position 130 (e.g., a magnetic detent position), and a second end position 132. The center detent position 130 can be disposed axially between the first end position 128 and the second end position 132. In some non-limiting examples, the multi-stable solenoid 100 can define two or more (e.g., 2, 4, 5, 6, etc.) stable positions for the armature 124.

[0027] As shown in the graph of FIG. 4, the magnetic components within the multi-stable solenoid 100 (e.g., the housing 116) can generate varying forces on the armature 124 due to the magnetic interaction between the permanent magnet 126 and these magnetic components. Figure 2 The illustrated passive force versus stroke curve depicts the amount of force acting on the armature 124 as a function of position between the first end position 128 and the second end position 132 with the first wire coil 118, the second wire coil 120, and the third wire coil 122 all de-energized. In the illustrated non-limiting example, the passive force versus stroke curve is a sinusoidal curve. Figure 2 In the graph of FIG. 4, a positive force is acting to move the armature 124 to the right (from the perspective of FIG. 4). For example, the first end position 128 can be located at -4 mm on the x-axis of FIG. 4, the center detent position 130 can be located at the origin of FIG. 4, and the second end position 132 can be located at +4 mm on the x-axis of FIG. 4. In the illustrated non-limiting example, when the armature 124 is at the first end position 128, a negative force (i.e., a force that, from the perspective of FIG. 4, forces the armature 124 to the left) acts on the armature 124, and a positive force greater than this inherent static force is required to move the annular armature 124 toward the center detent position 130. Figure 2 Figure 2 In the graph of FIG. 4, a positive force is acting to move the armature 124 to the right (from the perspective of FIG. 4). For example, the first end position 128 can be located at -4 mm on the x-axis of FIG. 4, the center detent position 130 can be located at the origin of FIG. 4, and the second end position 132 can be located at +4 mm on the x-axis of FIG. 4. In the illustrated non-limiting example, when the armature 124 is at the first end position 128, a negative force (i.e., a force that, from the perspective of FIG. 4, forces the armature 124 to the left) acts on the armature 124, and a positive force greater than this inherent static force is required to move the annular armature 124 toward the center detent position 130. Figure 2 Figure 2 In the graph of FIG. 4, a positive force is acting to move the armature 124 to the right (from the perspective of FIG. 4). For example, the first end position 128 can be located at -4 mm on the x-axis of FIG. 4, the center detent position 130 can be located at the origin of FIG. 4, and the second end position 132 can be located at +4 mm on the x-axis of FIG. 4. In the illustrated non-limiting example, when the armature 124 is at the first end position 128, a negative force (i.e., a force that, from the perspective of FIG. 4, forces the armature 124 to the left) acts on the armature 124, and a positive force greater than this inherent static force is required to move the annular armature 124 toward the center detent position 130. Figure 2 Figure 3 In the graph of FIG. 4, a positive force is acting to move the armature 124 to the right (from the perspective of FIG. 4). For example, the first end position 128 can be located at -4 mm on the x-axis of FIG. 4, the center detent position 130 can be located at the origin of FIG. 4, and the second end position 132 can be located at +4 mm on the x-axis of FIG. 4. In the illustrated non-limiting example, when the armature 124 is at the first end position 128, a negative force (i.e., a force that, from the perspective of FIG. 4, forces the armature 124 to the left) acts on the armature 124, and a positive force greater than this inherent static force is required to move the annular armature 124 toward the center detent position 130.

[0028] To facilitate movement of the armature 124 along its path between the first end position 128 and the second end position 132, various combinations of the first wire coil 118, the second wire coil 120, and the third wire coil 122 can be selectively energized (i.e., have current applied in a desired direction). For example, one, two, or all of the first wire coil 118, the second wire coil 120, and the third wire coil 122 can be energized at different times to provide a predetermined force in a desired direction on the armature 124 and move the armature 124 to one of the first end position 128, the center detent position 130, or the second end position 132. ​​​

[0029] Figure 3 Two non-limiting examples of force versus stroke curves for two firing conditions (i.e., moving the armature 124 between two positions) for a given configuration of the first wire coil 118, the second wire coil 120, and the third wire coil 122 are shown. The configuration of the first wire coil 118, the second wire coil 120, and the third wire coil 122 and the current applied thereto can change the shape and position of the force versus stroke curve on the y-axis.

[0030] In the non-limiting example shown, curve 134 (firing) shows a configuration for firing from the center detent position 130 to the second end position 132. As Figure 3 shown, the force generated is always positive, indicating that the armature 124 is forced toward the second end position 132. Curve 136 (extinguishing) shows a configuration for firing from the second end position 132 to the center detent position 130. As Figure 4 shown, the force generated is always negative until the center detent position 130. The force versus stroke characteristics of the firing conditions from the first end position 128 or the second end position 132 to the center detent position 130 can result in unwanted overshoot (i.e., the armature travels beyond the desired center detent position 130).

[0031] In general, the movement of the ring-shaped armature 124 is governed by the conservation of energy. For example, as Figure 5 shown, for curve 136, the amount of work done on the armature 124 to accelerate from the second end position 132 to the center detent position 130 is much greater than the amount of work done on the armature 124 to decelerate. Thus, physics will dictate that the armature 124 can possess enough momentum upon reaching the center detent position 130 to travel beyond the center detent position 130 and, in some cases, undesirably to the next stable position.

[0032] Figure 6One non-limiting example of a multi-stable solenoid 100 is shown that is designed to resist or substantially prevent overshoot of the armature 124 upon firing from one of a first end position 128 and a second end position 132 to a center detent position 130. Generally, the multi-stable solenoid 100 can include one or more magnetic dampers 138 disposed along a travel path of the armature 124. In the non-limiting example shown, the multi-stable solenoid 100 can include a first damping ring 140, a second damping ring 142, and a third damping ring 144. The first damping ring 140, the second damping ring 142, and the third damping ring 144 can be disposed at least partially within the housing 116. In the non-limiting example shown, the first damping ring 140, the second damping ring 142, and the third damping ring 144 can be disposed at an end of the housing 116 radially adjacent to the armature 124, with the housing 116 including a radially extending arm or finger 146 that axially separates the first damping ring 140, the second damping ring 142, and the third damping ring 144. The first wire coil 118 can be enclosed by the housing 116 and the first damping ring 140, the second wire coil 120 can be enclosed by the housing 116 and the second damping ring 142, and the third wire coil 122 can be enclosed by the housing 116 and the third damping ring 144.

[0033] In some non-limiting examples, the first damping ring 140, the second damping ring 142, and the third damping ring 144 can be made of an electrically conductive, non-ferromagnetic material. In some non-limiting examples, the first damping ring 140, the second damping ring 142, and the third damping ring 144 can be electrically conductive circumferentially to form a closed conductive path (e.g., electrically conductive in a closed path that travels circumferentially around the central axis 108).

[0034] Generally, a speed-dependent magnetic damping force can be generated on the annular armature 124 as the annular armature 124 travels between a first end position 128, a center stop position 130, and a second end position 132. As the armature 124 and the permanent magnets 126 move between stable positions, a changing magnetic field is generated relative to the one or more magnetic dampers 138. This changing magnetic field induces currents within the one or more magnetic dampers 138, generating a resulting opposing magnetic damping force. By adding the first, second, and third damping rings 140, 142, and 144 along the travel path of the armature 124, the magnetic damping force generated on the armature 124 can be increased (when compared to a configuration that does not include the damping rings), and the magnitude and direction of the damping force can help to inhibit or substantially prevent the annular armature 124 from overshooting when firing toward the center stop position 130. Additionally, as the armature 124 travels to the first end position 128 or the second end position 132 , the magnitude and direction of the damping force provided by the combined effect of the first damping ring 140 , the second damping ring 142 , and the third damping ring 144 may also help to mitigate or reduce impact forces.

[0035] like Figure 6 As shown, the use of the first damping ring 140, the second damping ring 142, and the third damping ring 144 can significantly change the magnetic damping force characteristics of the multistable solenoid 100. For example, for a given firing condition, the first damping ring 140, the second damping ring 142, and the third damping ring 144 can change the damping force to a generally parabolic shape. For example, when firing from the first end position 128 toward the center stop position 130 (i.e., curve 148), the magnetic damping force can initially increase (in absolute value) and then decrease as the annular armature 124 reaches the center stop position 130. As shown in FIG. Figure 6 As shown, the damping force of curve 148 is negative, corresponding to acting in an axial direction from right to left. When the armature 124 moves from the first end position 128 to the center stop position 130, the armature 124 is displaced in an axial direction from left to right. Therefore, the damping force generated by the one or more magnetic dampers 138 (e.g., one or more damping rings) acts in a direction opposite to the direction of movement of the armature 124.

[0036] Similarly, when firing from the second end position 132 toward the center stop position 130 (ie, curve 150), the magnetic damping force may initially increase (in absolute value) and then decrease as the annular armature 124 reaches the center stop position 130. Figure 6As shown, the damping force of curve 150 is positive, corresponding to acting axially from left to right. As the armature 124 moves from the second end position 132 to the center stop position 130, the armature 124 is displaced in the axial direction from right to left. Once again, the damping force generated by the one or more magnetic dampers 138 (e.g., one or more damping rings) acts in a direction opposite to the direction of movement of the armature 124. In this manner, for example, the magnetic damping force generated by using the first damping ring 140, the second damping ring 142, and the third damping ring 144 can act to limit the momentum of the armature 124 as it travels from one of the first end position 128 and the second end position 132 to the center stop position 130. Thus, the armature 124 can be prevented or substantially prevented from excessively overshooting past the center stop position 130, ensuring efficient and accurate operation of the multistable solenoid 100.

[0037] As described herein, the damping force generated by the one or more magnetic dampers 138 (e.g., one or more damping rings) can be the result of a changing magnetic field generated by the movement of the armature 124 relative to the one or more magnetic dampers 138 (e.g., one or more damping rings). Thus, the generation of the damping force can be initiated by the movement of the armature 124 relative to at least one of the first damping ring 140, the second damping ring 142, and the third damping ring 144, as described herein. Figure 7 For example, the magnitude of the damping force of curve 148 at the first end position 128 may be zero, and once the armature 124 begins to move toward the center stop position 130, an increase in the damping force (in absolute value) may occur. Similarly, the magnitude of the damping force of curve 150 at the second end position 132 may be zero, and once the armature 124 begins to move toward the center stop position 130, an increase in the damping force (in absolute value) may occur. Therefore, the magnitude of the damping force generated by the one or more magnetic dampers 138 (e.g., one or more damping rings) may be speed- or velocity-dependent. That is, if the armature 124 is not moving (e.g., at zero velocity), no damping force may be generated. Once the armature 124 begins to move (i.e., the absolute value of the velocity is greater than zero), the one or more magnetic dampers 138 (e.g., one or more damping rings) may generate a damping force in a direction opposite to the direction of movement of the armature 124, with the magnitude of the damping force being related to the absolute value of the velocity of the armature 124.

[0038] Figure 7 The benefits of one or more magnetic dampers 138 are further illustrated. ​As shown, without the use of one or more magnetic dampers 138 (curve 149), the overshoot (i.e., travel beyond the center stop position 130) is greater, and the annular armature 124 takes longer to reach a stable condition at the center stop position 130. In other words, including one or more magnetic dampers 138 (curve 151) reduces the overshoot beyond the center stop position 130 and becomes stable at the center stop position 130 more quickly.

[0039] In addition to the desired effect related to the overshoot of the armature 124, the use of the first damping ring 140, the second damping ring 142, and the third damping ring 144 also provides a solution that is largely independent of the magnetic saturation of the housing (i.e., the damping force is not affected by magnetic saturation). Furthermore, no other ferromagnetic components of the multistable solenoid 100 need to be changed to accommodate the first damping ring 140, the second damping ring 142, and the third damping ring 144. For example, the shape and size of the housing 116 and the other magnetic components within the multistable solenoid 100 can remain unchanged, which results in unchanged static magnetostatic characteristics. Therefore, for a given application, the static magnetostatic requirements of the multistable solenoid 100 can be decoupled from the dynamic requirements, which greatly reduces the complexity of the design process. Furthermore, by using the first damping ring 140, the second damping ring 142, and the third damping ring 144, the efficiency of the magnetic material of the design can be maintained.

[0040] In this specification, the embodiments of the present invention have been described in a manner that enables a clear and concise description to be written, but it is intended and will be understood that the embodiments may be combined or separated in different ways without departing from the present invention. For example, it should be understood that all preferred features described herein are applicable to all aspects of the invention described herein.

[0041] Therefore, although the invention has been described in conjunction with particular embodiments and examples, the invention is not necessarily so limited, and many other embodiments, examples, uses, modifications, and departures from the described embodiments, examples, and uses are intended to be covered by the appended claims. The entire disclosure of each patent and publication cited herein is incorporated herein by reference as if each such patent or publication were individually incorporated herein by reference.

[0042] Various features and advantages of the invention are set forth in the following claims.

Claims

1. A solenoid comprising: Wire coil; an armature comprising a permanent magnet, wherein the armature is movable between two or more stable positions in response to selective energization of the wire coil; as well as one or more magnetic dampers, arranged along the travel path of the armature, The one or more magnetic dampers are configured to generate a magnetic damping force in a direction opposite to the movement of the armature to limit overshoot when the armature travels to one of the two or more stable positions, wherein the one or more magnetic dampers are electrically conductive and non-ferromagnetic.

2. The solenoid of claim 1, further comprising a housing.

3. The solenoid according to claim 2, wherein: The wire coil is disposed within the housing.

4. The solenoid according to claim 3, wherein The wire coil is formed from a single continuous coil that is divided into one or more wire coil bays that are axially separated from each other.

5. The solenoid according to claim 4, wherein The housing includes one or more fingers axially separating the one or more wire coil bays.

6. The solenoid according to claim 3, wherein The wire coil includes one or more individual wire coils axially separated from each other.

7. The solenoid according to claim 6, wherein The housing includes one or more fingers that axially separate the one or more individual wire coils.

8. The solenoid according to claim 2, wherein: The shell is made of ferromagnetic material.

9. The solenoid according to claim 2, wherein: The one or more magnetic dampers are at least partially disposed within the housing.

10. The solenoid according to claim 1, wherein The two or more stable positions include three or more stable positions including a first end position, a center stop position, and a second end position.

11. The solenoid according to claim 10, wherein With the wire coil de-energized, the armature is stable in at least one of the first end position, the center stop position, and the second end position.

12. The solenoid according to claim 1, wherein The one or more magnetic dampers are circumferentially electrically conductive to form a closed electrically conductive path.

13. The solenoid of claim 1, wherein: In addition to the permanent magnets, the armature also comprises one or more ferromagnetic components.

14. The solenoid of claim 1, wherein: The magnitude of the magnetic damping force depends on the speed of the armature.

15. A solenoid comprising: Wire coil; an armature comprising a permanent magnet, wherein the armature is movable between two or more stable positions in response to selective energization of the wire coil; as well as two or more magnetic dampers; each of the two or more magnetic dampers is arranged at a corresponding one of the two or more stable positions along the travel path of the armature, wherein the two or more magnetic dampers are configured to generate a magnetic damping force in response to relative movement between the armature and at least one of the two or more magnetic dampers, and The direction of the magnetic damping force is opposite to the direction of movement of the armature to limit overshoot when the armature moves to one of the two or more stable positions.

16. The solenoid of claim 15, wherein: The magnitude of the magnetic damping force depends on the speed of the armature.

17. The solenoid of claim 15, wherein: The two or more stable positions include three or more stable positions including a first end position, a center stop position, and a second end position.

18. The solenoid of claim 17, wherein: With the wire coil de-energized, the armature is stable in at least one of the first end position, the center stop position, and the second end position.

19. The solenoid of claim 15, wherein: The two or more magnetic dampers are electrically conductive and non-ferromagnetic, and wherein the two or more magnetic dampers are circumferentially electrically conductive to form a closed electrically conductive path.

Images