Patent Grant
8188817
The present invention relates to relays. More specifically, the present invention relates to double-pole-double-throw (DPDT) and other multi-pole-multi-throw (MPDT) electromechanical relays and to methods of making DPDT and other MPDT electromechanical relays.
Relays are electromechanical switches operated by a flow of electricity in one circuit and controlling the flow of electricity in another circuit. A typical relay consists basically of an electromagnet with a soft iron bar, called an armature, held close to it. A movable contact is connected to the armature in such a way that the contact is held in its normal position by a spring. When the electromagnet is energized, it exerts a force on the armature that overcomes the pull of the spring and moves the contact so as to either complete or break a circuit. When the electromagnet is de-energized, the contact returns to its original position. Variations on this mechanism are possible: some relays have multiple contacts; some are encapsulated; some have built-in circuits that delay contact closure after actuation; some, as in early telephone circuits, advance through a series of positions step by step as they are energized and de-energized, and some relays are of latching type.
Relays are classified by their number of poles and number of throws. The pole of a relay is the terminal common to every path. Each position that the pole can connect to is called a throw. A relay can be made of n poles and m throws. For example, a single-pole-single-throw relay (SPST) has one pole and one throw. A single-pole-double-throw (SPDT) relay has one pole and two throws. A double-pole-double-throw (DPDT) relay has two poles, each with two simultaneously controlled throws.
Relays are then classified into forms. Relay forms are categorized by the number of poles and throws as well as the default position of the relay. Three common relay forms are: A, B, and C. Form A relays are SPST with a default state of normally open. Form B relays are SPST with a default state of normally closed. Form C relays are SPDT and break the connection with one throw before making contact with the other (break-before-make).
Latching relays are the types of relays which can maintain closed and open contact positions without energizing an electromagnet. Short current pulses are used to temporally energize the electromagnet and switch the relay from one contact position to the other. An important advantage of latching relays is that they do not consume power (actually they do not need a power supply) in the quiescent state.
A recent U.S. patent (U.S. Pat. No. 7,482,899 B2) describes a new type of electromechanical relay which employs a movable first magnet and a nearby third electromagnet. The movable first magnet is permanently magnetized with a magnetic moment and has a first end and a second end. The third electromagnet, when energized, produces a third magnetic field which is primarily perpendicular to the magnetization direction of the first movable magnet and exerts a magnetic torque on the first magnet to force the first magnet to rotate and closes an electrical conduction path at the first end. Changing the direction of the electrical current in the third electromagnet changes the direction of the third magnetic field and thus the direction of the magnetic torque on the first magnet, and causes the first magnet to rotate in an opposite direction and opens the electrical conduction path at the first end and closes an electrical conduction path at the second end. A second magnet is provided to hold the first magnet in a stable position.
A purpose of the present invention is to provide a new and improved electromechanical relay which is in the form of double-pole-double-throw.
A double-pole-double-throw electromechanical relay comprises a movable first magnet and a nearby third electromagnet (e.g., a coil or solenoid). The movable first magnet is permanently magnetized and has a first end and a second end. The third electromagnet, when energized, produces a third magnetic field which is primarily perpendicular to the magnetization direction of the first movable magnet and exerts a magnetic torque on the first magnet to force the first magnet to rotate and closes two independent electrical conduction paths at the first end. Changing the direction of the electrical current in the third electromagnet changes the direction of the third magnetic field and thus the direction of the magnetic torque on the first magnet, and causes the first magnet to rotate in an opposite direction and opens the two electrical conduction paths at the first end and closes two other independent electrical conduction paths at the second end. Latching and non-latching types of relays in various forms (A, B, and C) can be formed by appropriately using soft and permanent magnets as various components.
The above and other features and advantages of the present invention are hereinafter described in the following detailed description of illustrative embodiments to be read in conjunction with the accompanying figures, wherein like reference numerals are used to identify the same or similar parts in the similar views, and:
It should be appreciated that the particular implementations shown and described herein are examples of the invention and are not intended to otherwise limit the scope of the present invention in any way. Indeed, for the sake of brevity, conventional electronics, manufacturing, and other functional aspects of the systems (and components of the individual operating components of the systems) may not be described in detail herein. Furthermore, for purposes of brevity, the invention is frequently described herein as pertaining to an electromagnetic relay for use in electrical or electronic systems. It should be appreciated that many other manufacturing techniques could be used to create the relays described herein, and that the techniques described herein could be used in mechanical relays, optical switches, fluidic control systems, or any other switching devices. Further, the techniques would be suitable for application in electrical systems, optical systems, consumer electronics, industrial electronics, wireless systems, space applications, fluidic control systems, medical systems, or any other application. Moreover, it should be understood that the spatial descriptions made herein are for purposes of illustration only, and that practical latching relays may be spatially arranged in any orientation or manner. Arrays of these relays can also be formed by connecting them in appropriate ways and with appropriate devices.
Movable body 10 comprises a magnetic body 11 (first magnet), flexure spring and support 12, a pivot 15, and electrical contacts 13 and 14. Magnetic body 11 (first magnet) comprises permanent (hard) magnetic material and is permanently magnetized primarily along the positive x-axis when said first magnet 11 lies leveled. Other magnetization orientation of magnetic layer 11 is also possible as long as it achieves the function and purpose of this invention. Movable body 10 has a first (right) end associated with the first (right) end of first magnet 11 and contact 13, and has a second (left) end associated with the second (left) end of first magnet 11 and contact 14. The permanent (hard) magnetic material in first magnet 11 can be any type of hard magnetic material that can retain a remnant magnetization in the absence of an external magnetic field and its remnant magnetization cannot be easily demagnetized. In an exemplary embodiment, the permanent (hard) magnetic material is SmCo with an approximate remnant magnetization (Br=μ0M) of about 1 T predominantly along the positive x-axis when it lies leveled. Other possible hard magnetic materials are, for example, NdFeB, AlNiCo, Ceramic magnets (made of Barium and Strontium Ferrite), CoPtP alloy, and others, that can maintain a remnant magnetization (Br=μ0M) from about 0.001 T (10 Gauss) to above 1 T (104 Gauss), with coercivity (Hc) from about 7.96×102 A/m (10 Oe) to above 7.96×105 A/m (104 Oe). First magnet 11 has a magnetic moment m predominantly along the positive x-axis when first magnet 11 lies leveled. Flexure spring and support 12 can be any flexible material that on one hand supports movable body 10 and on the other allows body 10 to be able to move and rotate. Flexure spring and support can be made of metal layers (such as Beryllium Copper, Ni, stainless steel, etc.), or non-metal layers (such as polyimide, Si, Si3Ni4, etc.). The flexibility of the flexure spring can be adjusted by its thickness, width, length, shape, and elasticity, etc. Pivot 15 further supports movable body 10 to maintain a gap between body 10 and soft magnetic layer 31. Pivot 15 can be placed on the top of body 10 to maintain a gap between body 10 and soft magnetic layer 32. Electrical contacts 13 and 14 can be any electrically conducting layer such as Au, Ag, Rh, Ru, Pd, AgCdO, Tungsten, etc., or suitable alloys. Electrical contacts 13 and 14 can be formed onto the tips (ends) of body 10 by electroplating, deposition, welding, lamination, or any other suitable means. Flexure spring and support 12 and electrical contacts 13 and 14 can be formed by either using one process and the same material, or by using multiple processes, multiple layers, and different materials. When body 10 rotates and its two ends move up or down, electrical contact 13 (or 14) either makes or breaks the electrical connection with the bottom contact 41 (or 42). Optional insulating layers (not shown) can be placed between the conducting layers to isolate electrical signals in some cases.
Coil 20 (third electromagnet) is formed by having multiple windings of conducting wires around body 10. The conducting wires can be any conducting materials such as Cu, Al, Au, or others. The windings can be formed by either winding the conducting wires around a bobbin, or by electroplating, deposition, screen printing, etching, laser forming, or other means used in electronics industry (e.g., semiconductor integrated circuits, printed circuit boards, etc.). One purpose of coil 20 in relay 100, when energized, is to provide a third vertical (along y-axis) magnetic field (Hs) so that a magnetic torque (τ=μ0m×Hs) can be created on body 10. Because the magnetic moment m in first magnet 11 is fixed, the direction and magnitude of the torque depends on the direction and magnitude of the current in coil 20. This arrangement provides a means for external electronic control of the relay switching between different states, as to be explained in detail below.
Soft magnetic layers 31 (second magnet) and 32 can be any magnetic material which has high permeability (e.g., from about 100 to above 105) and can easily be magnetized by the influence of an external magnetic field. Examples of these soft magnetic materials include permalloy (NiFe alloys), Iron, Silicon Steels, FeCo alloys, soft ferrites, etc. One purpose of soft magnetic layers 31 and 32 is to form a closed magnetic circuit (indicated by dashed lines with arrows in
Electrical contacts 41 and 42 can be any electrically conducting layer such as Au, Ag, Rh, Ru, Pd, AgCdO, Tungsten, etc., or suitable alloys. Electrical contacts 41 and 42 can be formed on a substrate 33 by electroplating, deposition, screen printing, welding, lamination, or any other suitable means. Optional insulating layers (not shown) can be placed between the conducting layers to isolate electrical signals in some cases. Transmission-line types of contacts and metal traces can also be suitably designed and formed for high performance radio-frequency applications.
Substrate 33 can be any suitable structural material (plastic, ceramics, semiconductors, metal coated with thin films, etc.).
In a broad aspect of the invention, an electromagnet 20, when energized, produces a third magnetic field which is primarily perpendicular to the magnetization direction of first movable magnet 11 and exerts a magnetic torque on first magnet 11 to force first magnet 11 and body 10 to rotate and close an electrical conduction path at one end (e.g., first end) of body 10. Changing the direction of the electrical current in third electromagnet 20 changes the direction of the third magnetic field and thus the direction of the magnetic torque on first magnet 11, and causes first magnet 11 and body 10 to rotate in an opposite direction and opens the electrical conduction path at the end (e.g., first end) of body 10 and closes the electrical conduction path at the other end (e.g., second end).
With continued reference to
Some of the aforementioned advantages of the disclosed invention can be evidenced by the following exemplary analysis.
Assuming the first magnet having the following characteristics: length=4 mm (along long axis), width=4 mm, thickness=0.2 mm, volume V=length×width×thickness, remnant magnetization Br=μ0M=1 T, the magnetic moment μ0m=μ0M×V=3.2×10−9 T·m3. For a coil-induced magnetic field μ0Hs=0.05 T (Hs=500 Oe), the induced magnetic torque about the length center is τ=μ0m×Hs=1.27×10−4 m·N (assuming m is perpendicular to Hs) which corresponds to a force of Fm=τ/(length/2)=6.4×10−2 N at the end of the first magnet. The above exemplary parameters show that for a relatively small coil-induced magnetic field (Hs=500 Oe), a significantly large torque and force can be generated. The torque and force can continue to increase with larger Hs (correspondingly larger coil current). Another point worth noting is that when the angle between m and Hs changes from perfectly perpendicular (90°) to 80°, the change in the magnitude of the torque (and force) is only 1.5%=1−98.5%=1−sin(80°), which gives a larger tolerance in production variations, simplifies the production process, and reduces costs.
Movable body 10 comprises a magnetic body 11 (first magnet), springs s1 and s2, top (movable) electrical contacts (not shown), and an over-mold 16. A pivot 15 is placed below movable body 10 for further support.
Magnetic body 11 (first magnet) comprises permanent (hard) magnetic material and is permanently magnetized primarily along the positive x-axis when said first magnet 11 lies leveled.
Springs s1 and s2 can be made from metal (e.g., BeCu, Ni, NiFe, etc.). Spring s1 is electrically connected to terminal p1 at w1 by spot welding, soldering, or other means. Spring s2 is electrically connected to terminal p2 at w2 by spot welding, soldering, or other means. Other locations for spring and terminal welding are also possible. Electrical contacts (not shown) are affixed (by spot welding, etc.) to the ends of springs s1 and s2 for making electrical contact to the bottom electrical contacts. The electrical contacts can be any electrically conducting layer such as Au, Ag, Rh, Ru, Pd, AgCdO, Tungsten, etc., or suitable alloys. Springs s1 and s2 are flexible so that they can bend (near their ends) and twist (in the section toward w1 and w2).
Over-mold 16 affixes magnetic body 11 and springs s1 and s2 together to form a unified body (movable body 10). Over-mold 16 can be made from plastic material such as liquid crystal polymers (LCP), or any other suitable molding material.
Pivot 15 can be formed by molding from the same substrate 33 or by shaping of soft magnet layer 31.
Movable Body 10 has a first (right) end associated with the first (right) end of first magnet 11 and contacts b11 and b21, and has a second (left) end associated with the second (left) end of first magnet 11 and contacts b12 and b22.
Coil 20 (third electromagnet) is formed by having multiple windings of conducting wires around body 10. The conducting wires can be any conducting materials such as Cu, Al, Au, or others. The windings can be formed by either winding the conducting wires around a bobbin, or by electroplating, deposition, screen printing, etching, laser forming, or other means used in electronics industry (e.g., semiconductor integrated circuits, printed circuit boards, etc.). One end of coil 20 is connected to terminal c1 and the other end of coil 20 is connected to terminal c2. Coil 20 is over-molded (molding 21) with a plastic material (LCP) or other suitable molding material. A cavity 22 is formed in molding 21 to allow movable body 20 (including springs s1 and s2) to rotate or move. One purpose of coil 20 in relay 200, when energized, is to provide a third vertical (along y-axis) magnetic field (Hs) so that a magnetic torque (τ=μ0m×Hs) can be created on first magnet 11 to cause movable body 10 to rotate.
Soft magnetic layers 31 (second magnet) and 32 can be any magnetic material which has high permeability (e.g., from about 100 to above 105) and can easily be magnetized by the influence of an external magnetic field. Examples of these soft magnetic materials include permalloy (NiFe alloys), Iron, Silicon Steels, FeCo alloys, soft ferrites, etc. In this embodiment, soft magnetic layer 31 is placed below first magnet 11 and soft magnetic layer 32 is placed above first magnet 11.
Electrical terminals p1, t11, t12, p2, t21, t22, c1, and c2 can be any electrically conducting material such as Copper, NiFe, Ni, Steel, etc. All or part of the electrical terminals can be molded with substrate 33. Various patterns can be formed on the layer that forms the electrical terminals so that each terminal can extend from the outside edges of relay 200 into the inside to form electrical contact pads and conduction paths.
Bottom (stationary) electrical contacts b11, b12, b21, b22 can be any electrically conducting layer such as Au, Ag, Rh, Ru, Pd, AgCdO, Tungsten, etc., or suitable alloys. Bottom electrical contact b11 is connected to terminal t11 and bottom electrical contact b12 is electrically connected to terminal t12. Bottom electrical contact b21 is connected to terminal t21 and bottom electrical contact b22 is electrically connected to terminal t22.
Substrate 33 can be any suitable structural material (plastic, ceramics, metal coated with thin films, etc.).
Upper body 200A and lower body 200B are assembled together to form relay 200. Epoxy or other types of glues can be applied at the bottom to seal relay 200. A small hole can be formed in substrate 33 or molding 21 and later sealed. Additional capping covers (made of metal or plastic material, etc.) can be added for magnetic and electronic screening or for encapsulation purposes.
In a broad aspect of the invention, coli 20, when energized, produces a third magnetic field which is primarily perpendicular to the magnetization direction of first movable magnet 11 and exerts a magnetic torque on first magnet 11 to force first magnet 11 and body 10 to rotate and close electrical conduction paths at one end (e.g., first end) of body 10. Changing the direction of the electrical current in third electromagnet 20 changes the direction of the third magnetic field and thus the direction of the magnetic torque on first magnet 11, and causes first magnet 11 and body 10 to rotate in an opposite direction and opens the electrical conduction path at one end (e.g., first end) of body 10 and closes the electrical conduction paths at the other end (e.g., second end).
When electromagnet 20 is not energized, body 10 can be in the neutral (leveled) position and maintained in that position by the restoring spring force of the springs (s1 and s2) and pivot 15, or remains in one of the tilted states (one end down) when the magnetic attraction between that end of first magnet 11 and soft magnetic layer 31 (and/or soft magnetic layer 32) is strong enough to hold it there.
When movable body 10 is rotated clockwise and its first end (right end) touches down, the electrical conduction path from terminal p1 to terminal t11 is closed through top contacts at the right end of spring s1 and contact b11, and the electrical conduction path from terminal p2 to terminal t21 is closed through top contacts at the right end of spring s2 and contact b21. Electrical conduction paths between terminal p1 and t12 and electrical conduction paths between terminal p2 and t22 are open.
When movable body 10 is rotated counterclockwise and its second end (left end) touches down, the electrical conduction path from terminal p1 to terminal t12 is closed through top contacts at the left end of spring s1 and contact b12, and the electrical conduction path from terminal p2 to terminal t22 is closed through top contacts at the left end of spring s2 and contact b22. Electrical conduction paths between terminal p1 and t11 and electrical conduction paths between terminal p2 and t21 are open.
Movable body 10 comprises a magnetic body 11 (first magnet), springs s1 and s2, top (movable) electrical contacts (not shown), and an over-mold 16. A pivot 15 is placed below movable body 10 for further support.
Magnetic body 11 (first magnet) comprises permanent (hard) magnetic material and is permanently magnetized primarily along the positive x-axis when said first magnet 11 lies leveled.
Springs s1 and s2 can be made from metal (e.g., BeCu, Ni, NiFe, etc.). Spring s1 is electrically connected to terminal p1 at w1 by spot welding, soldering, or other means. Spring s2 is electrically connected to terminal p2 at w2 by spot welding, soldering, or other means. Other locations for spring and terminal welding are also possible. Electrical contacts (not shown) are affixed (by spot welding, etc.) to the ends of springs s1 and s2 for making electrical contact to the bottom electrical contacts. The electrical contacts can be any electrically conducting layer such as Au, Ag, Rh, Ru, Pd, AgCdO, Tungsten, etc., or suitable alloys. Springs s1 and s2 are flexible so that they can bend (near their ends) and twist (in the section toward w1 and w2).
Over-mold 16 affixes magnetic body 11 and springs s1 and s2 together to form a unified body (movable body 10). Over-mold 16 can be made from plastic material such as liquid crystal polymers (LCP), or any other suitable molding material.
Pivot 15 can be formed by molding from the same substrate 33 or by shaping of soft magnet layer 31.
Movable Body 10 has a first (right) end associated with the first (right) end of first magnet 11 and contacts b11 and b21, and has a second (left) end associated with the second (left) end of first magnet 11 and contacts b12 and b22.
Coil 20 (third electromagnet) is formed by having multiple windings of conducting wires around body 10. The conducting wires can be any conducting materials such as Cu, Al, Au, or others. The windings can be formed by either winding the conducting wires around a bobbin, or by electroplating, deposition, screen printing, etching, laser forming, or other means used in electronics industry (e.g., semiconductor integrated circuits, printed circuit boards, etc.). One end of coil 20 is connected to terminal c1 and the other end of coil 20 is connected to terminal c2. Coil 20 is placed or over-molded in substrate 33. One purpose of coil 20 in relay 300, when energized, is to provide a third vertical (along y-axis) magnetic field (Hs) so that a magnetic torque (τ=μ0m×Hs) can be created on first magnet 11 to cause movable body 10 to rotate.
Soft magnetic layers 31 (second magnet) and 32 can be any magnetic material which has high permeability (e.g., from about 100 to above 105) and can easily be magnetized by the influence of an external magnetic field. Examples of these soft magnetic materials include permalloy (NiFe alloys), Iron, Silicon Steels, FeCo alloys, soft ferrites, etc. In this embodiment, soft magnetic layer 31 is placed below first magnet 11 and soft magnetic layer 32 is placed above first magnet 11.
Electrical terminals p1, t11, t12, p2, t21, t22, c1, and c2 can be any electrically conducting material such as Copper, NiFe, Ni, Steel, etc. All or part of the electrical terminals can be molded with substrate 33. Various patterns can be formed on the layer that forms the electrical terminals so that each terminal can extend from the outside edges of relay 200 into the inside to form electrical contact pads and conduction paths.
Bottom (stationary) electrical contacts b11, b12, b21, b22 can be any electrically conducting layer such as Au, Ag, Rh, Ru, Pd, AgCdO, Tungsten, etc., or suitable alloys. Bottom electrical contact b11 is connected to terminal t11 and bottom electrical contact b12 is electrically connected to terminal t12. Bottom electrical contact b21 is connected to terminal t21 and bottom electrical contact b22 is electrically connected to terminal t22.
Substrate 33 can be any suitable structural material (plastic, ceramics, metal coated with thin films, etc.).
Upper part 300A and lower part 300B are assembled together to form relay 300. Epoxy or other types of glues can be applied at the bottom to seal relay 300. A small hole can be formed in substrate 33 or molding 61 and later sealed. Additional capping covers (made of metal or plastic material, etc.) can be added for magnetic and electronic screening or for encapsulation purposes.
In a broad aspect of the invention, coli 20, when energized, produces a third magnetic field which is primarily perpendicular to the magnetization direction of first movable magnet 11 and exerts a magnetic torque on first magnet 11 to force first magnet 11 and body 10 to rotate and close electrical conduction paths at one end (e.g., first end) of body 10. Changing the direction of the electrical current in third electromagnet 20 changes the direction of the third magnetic field and thus the direction of the magnetic torque on first magnet 11, and causes first magnet 11 and body 10 to rotate in an opposite direction and opens the electrical conduction path at one end (e.g., first end) of body 10 and closes the electrical conduction paths at the other end (e.g., second end).
When electromagnet 20 is not energized, body 10 can be in the neutral (leveled) position and maintained in that position by the restoring spring force of the springs (s1 and s2) and pivot 15, or remains in one of the tilted states (one end down) when the magnetic attraction between that end of first magnet 11 and soft magnetic layer 31 (and/or soft magnetic layer 32) is strong enough to hold it there.
When movable body 10 is rotated clockwise and its first end (right end) touches down, the electrical conduction path from terminal p1 to terminal t11 is closed through top contacts at the right end of spring s1 and contact b11, and the electrical conduction path from terminal p2 to terminal t21 is closed through top contacts at the right end of spring s2 and contact b21. Electrical conduction paths between terminal p1 and t12 and electrical conduction paths between terminal p2 and t22 are open.
When movable body 10 is rotated counterclockwise and its second end (left end) touches down, the electrical conduction path from terminal p1 to terminal t12 is closed through top contacts at the left end of spring s1 and contact b12, and the electrical conduction path from terminal p2 to terminal t22 is closed through top contacts at the left end of spring s2 and contact b22. Electrical conduction paths between terminal p1 and t11 and electrical conduction paths between terminal p2 and t21 are open.
It is understood that a variety of methods can be used to fabricate the DPDT electromechanical relay. It will be understood that many other embodiments and combinations of different choices of materials and arrangements could be formulated without departing from the scope of the invention. Similarly, various topographies and geometries of the electromechanical relay could be formulated by varying the layout of the various components.
The corresponding structures, materials, acts and equivalents of all elements in the claims below are intended to include any structure, material or acts for performing the functions in combination with other claimed elements as specifically claimed. Moreover, the steps recited in any method claims may be executed in any order. The scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given above.
This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/159,169, filed on Mar. 11, 2009, which is hereby incorporated by reference. This application is related to application Ser. No. 11/534,655, filed on Sep. 24, 2006, now U.S. Pat. No. 7,482,899 B2, issued on Jan. 27, 2009.
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| Number | Date | Country | |
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