Patent Application
20200251267
The present disclosure relates to a solenoid including a compressible or displaceable ferromagnetic member within the air gap.
This section provides background information related to the present disclosure, which is not necessarily prior art.
Solenoids include an “air gap” (a break in the material) so that force will be generated to pull a plunger, and so the plunger has space to move. The gap naturally adds a large reluctance to the system. The air gap can be considered as having radial and axial components. Many conventional solenoid designs generate force on the plunger by utilizing only the radial air gap or only the axial air gap to provide the primary axial force on the plunger. Other designs use both the radial and axial air gaps to provide axial force on the plunger. The axial air gap is typically large as compared to the radial air gap because the plunger moves axially. This large axial air gap has a large reluctance (due to the air) and therefore decreases the overall efficiency of the magnetic circuit.
In many solenoid applications, it is desirable to maximize magnetic force, while minimizing the size of the solenoid. To achieve high force in a small package size, tolerances can be reduced, thus reducing air gaps that act as large magnetic resistances or reluctances. However, such a solution is typically cost prohibitive. Another potential solution is to use materials having very high magnetic permeability. But this is also costly. Moreover, there are limits to the amount of magnetic force that can be achieved by reducing tolerances and optimizing material. The present disclosure overcomes these issues in the art and provides for numerous advantages and unexpected results, as explained in detail herein and as one skilled in the art will recognize.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
The present disclosure includes a solenoid having a first magnetic core and a second magnetic core defining an air gap between. A ferromagnetic member is within the air gap. The ferromagnetic member magnetically connects the first magnetic core and the second magnetic core to create a magnetic flux path between them. This flux results in an increased pull between the two cores. A solenoid coil surrounds at least one of the first magnetic core and the second magnetic core.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
With initial reference to
Seated within the axial air gap 24 is any suitable ferromagnetic member, such as the ferromagnetic member 30A illustrated in
The ferromagnetic member 30A (as well as any of the other ferromagnetic members 30B-30H set forth herein) has a low reluctance (such as lower than low carbon steel for example). The ferromagnetic member 30A (as well as any of the other ferromagnetic members 30B-30H set forth herein) is made of ferromagnetic material with exceptional magnetic properties (such as pure iron, amorphous steel, nanocrystalline steel, Mu Metal, Permalloy, and Permendur, for example) having a low spring constant.
The ferromagnetic member 30A creates a magnetic flux path by creating a direct connection between a top portion of the first magnetic core 20 and a bottom portion of the second magnetic core 22. This flux path results in an increased pull between the two cores 20 and 22. The ferromagnetic member 30A (as well as the other ferromagnetic members 30B-30H described herein) increases solenoid force by short circuiting the axial air gap 24 of the magnetic circuit between the first magnetic core 20 and the second magnetic core 22 with a (e.g. compressible) ferromagnetic medium. The ferromagnetic member 30A increases the axial force on the moving first magnetic core 20 (or both the first and second magnetic cores 20 and 22 when both cores 20 and 22 are movable) by reducing the reluctance in the axial air gap. The ferromagnetic member 30A does not have to directly touch the cores 20 and 22, as any of the components (first core 20, second core 22, ferromagnetic member 30A) may be treated with a thin, non-magnetic layer. Additionally, the ferromagnetic member 30A could be free-floating and never compress.
With additional reference to
With reference to
The shapes of the ferromagnetic materials 30A-30H advantageously maximize surface contact area and cross sectional area between the ferromagnetic materials 30A-30H and the first and second magnetic cores 20 and 22. This is in contrast to, for example, single start, round wire coil springs that have a small cross-sectional area that magnetically saturates quickly and limits flux flow.
With reference to
The present disclosure thus advantageously increases solenoid force by short circuiting the axial air gap 24 of the magnetic circuit between the first magnetic core 20 and the second magnetic core 22 with a ferromagnetic member 30A-30H (many of which are compressible ferromagnetic members). This advantageously increases the axial force on the moving first magnetic core 20 (and the second magnetic core 22 when movable) by reducing the reluctance in the axial air gap 24. Although the solenoid 10 is illustrated as including a single ferromagnetic member 30A-30H, multiple ferromagnetic members may be arranged in parallel or series.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
