Patent Grant
8581682
The subject matter described and/or illustrated herein relates generally to electrical switches, and more particularly, to solenoids for electrical switches.
Electrical switches (e.g., contactors, relays, and the like) exist today for opening and closing an electrical circuit between various electrical devices. For example, electrical switches are sometimes used to electrically connect and disconnect an electrical device from an electrical power source. Typical electrical switches include an actuator and one or more movable contacts connected to the actuator. Electrical current is applied to the actuator to move the movable contact into or out of engagement with stationary contacts that are electrically connected to corresponding ones of the electrical devices. The electrical circuit between the electrical devices is thereby completed or broken depending on whether the movable contact is engaged or disengaged with the stationary contacts.
The actuator of some known electrical switches is a solenoid, which may include a coil that surrounds a movable core. A ferromagnetic coil shell typically extends around the coil. Energization of the coil with electrical power generates a magnetic flux that moves the movable core within the coil. The movable core is connected to an actuator rod that is connected to the movable contact of the electrical switch. As the movable core moves within the coil, the actuator rod and movable contact move along with the movable core to engage or disengage the movable contact from the stationary contacts.
The coil, coil shell, and/or other components of the solenoid and/or switch are selected to provide a predetermined amount of magnetic flux. The predetermined magnetic flux provides a predetermined movement force for moving the movable contact into or out of engagement with the stationary contacts. The movement force may need to be high enough to overcome the friction and/or inertia of the movable core and/or other components of the solenoid and/or switch, such as the actuator rod. The predetermined magnetic flux also provides a predetermined contact force for holding the movable contact in engagement with or disengagement from the stationary contacts. The movement force and/or the contact force may also need to be high enough to overcome the bias of a spring that biases the movable contact to be disengaged from or engaged with the stationary contacts. But, to provide even relatively small increases to the predetermined magnetic flux, a size of the coil, the coil shell, and/or other ferromagnetic components of the solenoid and/or the switch may need to be increased more than is desired. As the size of the coil, coil shell, and/or other ferromagnetic components increases, the solenoid and/or the switch may become undesirably bulky and/or heavy. Moreover, the increased amount of ferromagnetic material used to fabricate the coil, the coil shell, and/or the other ferromagnetic components may increase a cost of the solenoid and/or the switch. Further, at least some of the increased magnetic flux may be wasted because the physical coupling between the coil and the movable core may decrease as the size of the coil increases.
In one embodiment, a solenoid is provided for an electrical switch. The solenoid includes a coil having a passageway extending therethrough along a central longitudinal axis. The solenoid also includes a movable core having a coil segment and a magnet segment. The coil segment is received within the passageway of the coil such that the coil extends around the coil segment. The magnet segment includes a radially outer surface relative to the central longitudinal axis of the passageway of the coil. The movable core is movable relative to the coil along the central longitudinal axis such that the coil segment is movable within the passageway of the coil along the central longitudinal axis. A permanent magnet extends around at least a portion of the radially outer surface of the magnet segment of the movable core. The movable core is movable along the central longitudinal axis relative to the permanent magnet.
In another embodiment, an electrical switch includes an electrical contact, an actuator rod connected to the electrical contact, and a solenoid. The solenoid includes a coil having a passageway extending therethrough along a central longitudinal axis, and a movable core having a coil segment and a magnet segment. The coil segment is received within the passageway of the coil such that the coil extends around the coil segment. The magnet segment includes a radially outer surface relative to the central longitudinal axis of the passageway of the coil. The movable core is movable relative to the coil along the central longitudinal axis. The movable core is connected to the actuator rod such that the actuator rod is movable with the movable core along the central longitudinal axis. Movement of the movable core moves the electrical contact into and out of engagement with a mating contact. The solenoid also includes a permanent magnet extending around at least a portion of the radially outer surface of the magnet segment of the movable core.
Referring again to
The spring 38 allows the moveable contact 14 to move with, and also relative to, the actuator rod 16. Specifically, and beginning in the open position shown in
In the exemplary embodiment, the solenoid 12 includes the auxiliary rod 56, which extends a length from an end 80 to an opposite end 82. The auxiliary rod 56 extends through the channel 72 of the stationary core 48 such that a portion of the length of the auxiliary rod 56 is received within the channel 72. The auxiliary rod 56 is configured to slidably move along the central longitudinal axis 58 relative to the stationary core 48. An optional bushing 84 surrounds the auxiliary rod 56 adjacent the end 60 of the stationary core 48. The bushing 84 extends between the auxiliary rod 56 and a surface of the stationary core 48 that defines the channel 72 for guiding and facilitating movement of the auxiliary rod 56 relative to the stationary core 48. The end 82 of the auxiliary rod 56 may be connected to one or more auxiliary movable contacts (not shown) for selectively engaging and disengaging the auxiliary movable contact with auxiliary stationary contacts (not shown). In other words, when the auxiliary movable contact is engaged with the auxiliary stationary contacts, the auxiliary movable contact completes an auxiliary electrical circuit between auxiliary electrical devices (not shown). Although shown as having a generally cylindrical shape, in addition or alternative the auxiliary rod 56 may include any other shape, such as, but not limited to, a rectangular shape and/or the like.
In some alternative embodiments, the stationary core 48 does not include the channel 72 and/or the spring perch 74. The channel 72 may alternatively only extend partially through the length of the stationary core 48. For example, the stationary core 48 may not include the channel 72 and/or the channel 72 may extend only partially through the length of the stationary core 48 in embodiments wherein the solenoid 12 does not include the auxiliary rod 56. Moreover, and for example, the stationary core 48 may not include the spring perch 74 in embodiments wherein the return spring 78 does not extend within the channel 72, but rather abuts the engagement surface 64 of the stationary core 48.
The movable core 46 extends a length along a central longitudinal axis 86 from an end 88 to an opposite end 90. In the exemplary embodiment, the central longitudinal axis 86 of the movable core 46 is aligned with the central longitudinal axis 58 of the stationary core 48. The end 90 of the movable core 46 includes an engagement surface 92 that engages the engagement surface 64 of the stationary core 48 during operation of the solenoid 12. The end 88 of the movable core 46 includes a flange 94 extending radially outward relative to the central longitudinal axis 86 of the movable core 46 (and radially outward relative to a central longitudinal axis 96 of the coil 50). The flange 94 includes a ledge 98. The movable core 46 includes a coil segment 100 and a magnet segment 102. Specifically, the magnet segment 102 includes the end 88 and the flange 94, and the coil segment 100 extends outwardly from the magnet segment 102 and includes the end 90. The magnet segment 102 includes a radially outer surface 103 relative to the central longitudinal axis 96 of the coil 50. A channel 104 extends through the length of the movable core 46. The channel 104 includes an optional spring perch 106 (not visible in
In the exemplary embodiment, the auxiliary rod 56 extends partially through the channel 104 of the movable core 46 such that a portion of the lens of the auxiliary rod 56 is received within the channel 104. The auxiliary rod 56 is connected to the movable core 46 for movement therewith along the central longitudinal axes 96 and 24 of the coil 50 and switch 10, respectively. The actuator rod 16 also extends partially through the channel 104 of the movable core 46 in the exemplary embodiment. Specifically, an end 110 of the actuator rod 16 that is opposite the end 36 is received within the channel 104. The end 110 of the actuator rod 16 abuts the end 80 of the auxiliary rod 56. The actuator rod 16 is connected to the movable core 46 for movement therewith along the central longitudinal axes 96 and 24 of the coil 50 and switch 10, respectively.
In alternative to the arrangement shown in
The coil 50 includes a passageway 112 extending through the coil 50 along the central longitudinal axis 96. In the exemplary embodiment, the central longitudinal axis 96 is aligned with the central longitudinal axis 24 of the switch 10. Moreover, in the exemplary embodiment, the central longitudinal axis 96 of the coil passageway 112 is aligned with the central longitudinal axes 58 and 86 of the stationary and movable cores 48 and 46, respectively. As can be seen in
The movable core 46 is movable relative to the coil 50 along the central longitudinal axis 96 of the coil passageway 112 such that the coil segment 100 of the movable core 46 is movable within the coil passageway 112 along the central longitudinal axis 96. The movable core 46 is movable along the central longitudinal axis 96 of the coil passageway 112 between an open position, shown in
The coil 50 is electrically connected to the electrical power source 18 (
Energization of the coil 50 with electrical power generates a magnetic flux that moves the movable core 46 along the central longitudinal axis 96 of the coil passageway 112. The magnetic flux of the coil 50 may be referred to herein as “coil flux”. In the exemplary embodiment, the magnetic flux of the coil 50 moves the movable core 46 along the central longitudinal axis 96 in the direction of the arrow B, against the bias of the return spring 78. In other words, in the exemplary embodiment, the magnetic flux of the coil 50 moves the movable core 46 from the open position to the closed position. In the exemplary embodiment, the switch 10 is a “normally open” switch because the movable core 46 is biased by the return spring 78 to the open position, because the open position of the movable core 46 corresponds to the open position of the movable contact 14, and because energization of the coil 50 with electrical power moves the movable core 46 to the closed position. Alternatively, the switch 10 is a “normally closed” switch. For example, in some alternative embodiments, the return spring 78 biases the movable core 46 to a position wherein the movable contact 14 is engaged with the stationary contacts 26 and 28 and energization of the coil 50 with electrical power generates a magnetic flux that moves the movable core 46, against the bias of the return spring 78, to a position wherein the movable contact 14 is disengaged from the stationary contacts 26 and 28. In such alternative embodiments wherein the switch 10 is a normally closed switch, the movable core 46 may be either engaged or disengaged with the stationary core 48 in the position of the movable core 46 wherein the movable contact 14 is engaged with the stationary contacts 26 and 28.
The coil shell 52 extends a length from an end 114 to an opposite end 116. The end 114 of the coil shell includes a recess 118 (not visible in
The permanent magnet 54 includes a body 127 extending from an end surface 128 to an opposite end surface 130. The body 127 of the permanent magnet 54 extends around at least a portion of the radially outer surface 103 of the magnet segment 102 of the movable core 46. In the exemplary embodiment, the permanent magnet 54 extends continuously around the radially outer surface 103 of the magnet segment 102 of the movable core 46. The permanent magnet 54 is positioned such that the end surface 128 faces the ledge 98 of the flange 94 of the movable core 46, and such that the end surface 128 is spaced apart from the ledge 98 of the flange 94 by a gap. Optionally, the permanent magnet 54 is held at least partially within the recess 124 within the coil lid 120.
As will be described below, the movable core 46 is movable along the central longitudinal axis 96 relative to the permanent magnet 54. The permanent magnet 54 generates a magnetic flux that applies a force to the movable core 46 that moves the movable core 46 along the central longitudinal axis 96. The magnetic flux of the permanent magnet 54 increases the amount of force applied to the movable core 46 by the magnetic flux of the coil 50. In other words, the force of the magnetic flux generated by the permanent magnet 54 is additive with the force of the magnetic flux generated by the coil 50. The magnetic flux of the coil 50 and the magnetic flux of the permanent magnet 54 thereby combine to move the movable core 46 along the central longitudinal axis 96 of the coil 50 in the direction of the arrow B. In some embodiments, the magnetic flux exerted on the movable core 46 by the permanent magnet 54 increases as the flange 94 of the movable core 46 moves toward the end surface 128 of the permanent magnet 54. The permanent magnet 54 may be selected to provide any level of magnetic flux to the movable core 46. The magnetic flux of the permanent magnet 54 may be referred to herein as “magnet flux”.
As best seen in
In the exemplary embodiment, the permanent magnet 54 is defined by a single body 127. Alternatively, the permanent magnet 54 is defined by at least two separate and distinct bodies 127 that each extend around a different portion of the radially outer surface 103 of the magnet segment 102 of the movable core 46. For example,
The permanent magnet 254 includes two separate and distinct bodies 327a and 327b. Each body 327a and 327b extends from a respective end surface 328a and 328b to an opposite end surface 330a and 330b, respectively. Each body 327a and 327b of the permanent magnet 254 extends around a different portion of the radially outer surface 303 of the magnet segment 302 of the movable core 246. The bodies 327a and 327b are positioned such that the respective end surfaces 328a and 328b face the ledge 298 of the flange 294 of the movable core 246, and such that the end surfaces 328a and 328b are spaced apart from the ledge 298 of the flange 294 by a gap. Optionally, the bodies 327a and 327b are held at least partially within the respective recesses 328a and 328b within the coil lid 320. Although two bodies 327a and 327b are shown and described herein, the permanent magnet 254 may include any number of the bodies 327. Moreover, although each body 327a and 327b is shown as extending around approximately half of the radially outer surface 303 of the movable core 246, each body 327a and 327b may alternatively extend around less than half of the radially outer surface 303.
In operation, and referring now to
Referring now to
Referring again to
The embodiments described and/or illustrated herein may provide a solenoid and/or a switch having a smaller and/or lighter coil, coil shell, and/or other ferromagnetic components for a given magnetic flux as compared with at least some known solenoids and/or switches. The embodiments described and/or illustrated herein may provide, for a given magnetic flux, a solenoid and/or a switch that is less expensive than at least some known solenoids and/or switches. The embodiments described and/or illustrated herein may provide a solenoid and/or a switch having a greater magnetic flux as compared with at least some known solenoids and/or switches of the same size and/or weight.
It is to be understood that the above description and the figures are intended to be illustrative, and not restrictive. For example, the above-described and/or illustrated embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the subject matter described and/or illustrated herein without departing from its scope. Dimensions, types of materials, orientations of the various components (including the terms “upper”, “lower”, “vertical”, and “lateral”), and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description and the figures. The scope of the subject matter described and/or illustrated herein should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means—plus-function format and are not intended to be interpreted based on 35 U.S.C. §112, sixth paragraph, unless and until such claim limitations expressly use the phrase “means for” followed by a statement of function void of further structure.
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| Number | Date | Country | |
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