Electromechanical switch with movable contact and damper

Abstract

An electromechanical switch (101) includes a housing (106), first and second fixed contacts (108, 109) mounted to the housing, a movable contact (124), and a carrier subassembly (126). The housing has a partition wall (156). The carrier subassembly includes a support bar (134) extending through an aperture (150) in the partition wall and coupled to the movable contact. The carrier subassembly is configured to move the movable contact relative to the first fixed contact and the second fixed contact. The carrier subassembly includes a contact spring (130) surrounding the support bar between the partition wall and the movable contact. The carrier subassembly also includes a damper (138) engaged with the contact spring. The damper is configured to absorb vibrations along one or more of the contact spring or the movable contact.

Description

[0001] This application is a divisional application of the invention patent application with the application number 2019800349244, the application date of April 9, 2019, and the invention title of "Electromechanical Switch with Movable Contact and Damper". Technical Field

[0002] The subject matter herein generally relates to electromechanical switches (e.g., contactors or relays) that control the flow of electrical power through a circuit. Background Art

[0003] Electromechanical switches can be used in a variety of applications where it is desired to selectively control the flow of electrical power (e.g., current). Electromechanical switches (e.g., contactors or relays) can include a movable contact and a plurality of fixed contacts. The movable contact selectively moves to engage or disengage the fixed contacts. When the movable contact engages the fixed contacts, electrical power can flow through the contacts. When the movable contact is spaced apart from the fixed contacts, electrical power does not flow through the contacts.

[0004] In certain applications, audible noise is generated along the interface between the movable contact and the fixed contacts. For example, electric vehicles use an electric vehicle battery (EVB) or a traction battery to power the vehicle. Such a battery can include a single battery cell having one or more contactors. When a person presses the accelerator pedal, the movable contact of at least one contactor moves to engage the fixed contacts. If the person quickly and / or deeply presses the accelerator pedal to rapidly accelerate the vehicle, a surge of current flows through the movable contact and the fixed contacts. This surge of current can cause the movable contact to oscillate and vibrate, thereby generating audible noise. The audible noise can distract or annoy the occupants of the vehicle as well as people near the vehicle. The problem to be solved is to provide an electromechanical switch that prevents or at least reduces audible noise caused by the oscillation of the contacts at the contact interface. Summary of the Invention

[0005] This problem is solved by an electromechanical switch that includes a housing, a first fixed contact and a second fixed contact mounted to the housing, a movable contact, and a carrier subassembly. The housing has a partition wall. The carrier subassembly includes a support rod that extends through an aperture in the partition wall and is connected to the movable contact. The carrier subassembly is configured to move the movable contact relative to the first fixed contact and the second fixed contact. The carrier subassembly includes a contact spring that surrounds the support rod between the partition wall and the movable contact. The carrier subassembly further includes a damper that engages the contact spring. The damper is configured to absorb vibrations along one or more of the contact spring or the movable contact. Brief Description of the Drawings

[0006] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0007] Figure 1 is a schematic diagram of a power circuit formed according to an exemplary embodiment, showing a cross-sectional view of an electromechanical switch of the power circuit in an open state.

[0008] Figure 2 is a schematic diagram of a power circuit in which the electromechanical switch is in a closed state, where the movable contact engages the fixed contact.

[0009] Figure 3 is Figure 1 an enlarged view of a part of the electromechanical switch shown in the open state.

[0010] Figure 4 is a perspective view of a damper of an electromechanical switch according to an embodiment.

[0011] Figure 5 is an enlarged view of a part of an electromechanical switch in an open state according to an alternative embodiment.

[0012] Figure 6 is a cross-sectional perspective view of a damper of an electromechanical switch according to an alternative embodiment.

[0013] Figure 7 is an enlarged view of a part of an electromechanical switch in an open state according to another alternative embodiment.

[0014] Figure 8 is according to Figure 7 a perspective view of a damper of an electromechanical switch according to the embodiment shown. DETAILED DESCRIPTION

[0015] Embodiments of the present disclosure provide an electromechanical switch, such as a relay or a contactor, configured to selectively establish and disconnect an electrical connection between a power source and an electrical device. The electromechanical switch can be configured to withstand high currents, such as 500 amperes (A) or higher.

[0016] When such a high level of power is transmitted across the mating interface between the mating contacts, the mating contacts of known electromechanical switches are prone to oscillation and / or vibration, which may generate audible noise. An observer may interpret the audible noise as a high-pitched squeal, which may distract the observer. The electromechanical switch according to the embodiments disclosed herein is configured to eliminate the audible noise, or at least reduce the occurrence and magnitude of the noise. For example, the electromechanical switch includes a damper engaged with a spring that applies a biasing force on the movable contact. The damper is configured to absorb the oscillation and vibration of the spring and / or the movable contact.

[0017] Figure 1FIG. 0 is a schematic diagram of a power circuit 100 formed according to an embodiment, showing a cross-sectional view of an electromechanical switch 101 of the power circuit 100 in an open state. The power circuit 100 has a number of components, including an electromechanical switch 101, a load power supply 102, an electrical load 104, and a switching power supply 112, as well as conductive elements 105, such as wires, traces, etc., to interconnect the components.

[0018] The electromechanical switch 101 is an electrically operated switch for selectively controlling the presence or absence of current flowing through the power circuit 100 from the load power supply 102 to the electrical load 104. The electromechanical switch 101 closes (or makes) the circuit to allow current to flow from the load power supply 102 to the electrical load 104 through the power circuit 100 to power the load 104. The electromechanical switch 101 opens (or breaks) the circuit to stop the flow of current to the electrical load 104 through the power circuit 100. The electromechanical switch 101 can be a relay device or a contactor device.

[0019] In a non-limiting example application, the power circuit 100 can be installed in a vehicle such as a hybrid or all-electric vehicle. The load power supply 102 can represent or include a battery. The electrical load 104 can represent or include an electric motor, a heating and / or cooling system, a lighting system, vehicle electronics, etc. The electromechanical switch 101 can also be used, for example, to transfer current from the electrical load 104 to the load power supply 102 in the reverse direction during regenerative braking of the vehicle to charge the load power supply 102. In other applications, the power circuit 100 can be used in other types of vehicles, such as railway vehicles and ships, appliances, industrial machinery, etc.

[0020] The electromechanical switch 101 includes a housing 106, a first fixed contact 108 and a second fixed contact 109, and a movable contact 124. The first fixed contact 108 and the second fixed contact 109 are mounted to the housing 106 and are fixed in a fixed position relative to the housing 106. The first fixed contact 108 is spaced apart from the second fixed contact 109. The first fixed contact 108 is electrically connected to the load power supply 102, and the second fixed contact 109 is electrically connected to the electrical load 104. The electromechanical switch 101 is Figure 1 shown in an open state, in which the movable contact 124 does not engage the fixed contacts 108, 109, thus no electrical connection is established. In the open state, the load power supply 102 is disconnected from the electrical load 104.

[0021] The movable contact 124 includes a mating side 202 and a mounting side 204 opposite the mating side 202. The mating side 202 faces the first fixed contact 108 and the second fixed contact 109. When the electromechanical switch 101 is in the closed position (as Figure 2As shown, the movable contact 124 engages both the first fixed contact 108 and the second fixed contact 109.

[0022] The electromechanical switch 101 also includes a coil 110 of wires (referred to herein as the wire coil 110) within the housing 106. The wire coil 110 is electrically connected to a switch power supply 112 via one or more conductive elements 107. The switch power supply 112 supplies current to the wire coil 110 to induce a magnetic field. The switch power supply 112 can be operated to selectively control the magnetic field induced by the wire coil 110.

[0023] The movable contact 124 is coupled to a carrier subassembly 126. The movable contact 124 and the carrier subassembly 126 together define the armature assembly 122 of the electromechanical switch 101. The armature assembly 122 moves bidirectionally along the actuation axis 128 relative to the fixed contacts 108, 109. In an embodiment, the movement of the armature assembly 122 can be based on the presence or absence of a magnetic field induced by the wire coil 110. For example, in response to the switch power supply 112 supplying current to the wire coil 110, the induced magnetic field acts on the carrier subassembly 126 and causes the carrier subassembly 126 and the movable contact 124 coupled thereto to move along the actuation axis 128 towards the fixed contacts 108, 109. In response to the switch power supply 112 stopping the current, the armature assembly 122 can axially return to the starting position due to a biasing force (such as gravity and / or spring force). Alternatively, the magnetic field induced by the coil 110 can force the armature assembly 122 to move in a direction away from the fixed contacts 108, 109, which disconnects the movable contact 124 from the fixed contacts 108, 109.

[0024] The carrier subassembly 126 includes a support rod 134, a plunger 132, a contact spring 130, and a damper 138. The support rod 134 extends between a first end 142 and an opposite second end 144 of the support rod 134. The support rod 134 is coupled to the movable contact 124 at or near the first end 142. For example, the first end 142 may extend through an opening 212 in the movable contact 124 that extends from the mating side 202 to the mounting side 204. The first end 142 may be coupled to the movable contact 124 via a clip 210 that engages the mating side 202 of the movable contact 124. In an alternative embodiment, the first end 142 of the support rod 134 may include a deflectable fork that latches onto the movable contact 124, instead of using the clip 210. The support rod 134 is coupled to the plunger 132 at or near the second end 144. For example, the second end 144 may extend into a channel 136 of the plunger 132 to secure the support rod 134 to the plunger 132 via a clip 214. Alternatively, the support rod 134 may be fixed to the plunger 132 via an interference fit, one or more deflectable latch features, an adhesive, and / or the like. The plunger 132 is securely fixed to the support rod 134. The movable contact 124 may be movably coupled to the support rod 134 such that the movable contact 124 is capable of moving axially relative to the support rod 134 toward the second end 144. The movable contact 124 and the plunger 132 are spaced apart from each other along the length of the support rod 134.

[0025] The housing 106 includes a partition wall 156 located between the movable contact 124 and the wire coil 110. The housing 106 is a container that defines an internal chamber 174 in the illustrated embodiment. The partition wall 156 segments the chamber 174 into a contact region 120 and an electromagnetic region 116. The fixed contacts 108, 109 and the movable contact 124 are at least partially located within the contact region 120. For example, the fixed contacts 108, 109 project from the chamber 174 of the housing 106 to electrically connect to the conductive elements 105. The wire coil 110 is disposed within the electromagnetic region 116.

[0026] The armature assembly 122 extends into both the contact region 120 and the electromagnetic region 116. For example, the partition wall 156 defines an aperture 150 that extends from the top side 158 of the partition wall 156 through the bottom side 160 of the partition wall 156. As used herein, relative or spatial terms such as "top", "bottom", "inner", "outer", "upper", and "lower" are used only to distinguish the referenced elements and do not necessarily require a specific position or orientation in the surrounding environment of the electromechanical switch 101. The support rod 134 extends through the aperture 150. The movable contact 124 and the plunger 132 are positioned on opposite sides of the partition wall 156. The movable contact 124 is located within the contact region 120, and the plunger 132 is located within the electromagnetic region 116. The armature assembly 122 moves relative to the partition wall 156 along the actuation axis 128.

[0027] The plunger 132 within the electromagnetic region 116 is circumferentially surrounded by the wire coil 110. The plunger 132 may be formed of a ferromagnetic material. For example, the plunger 132 may be formed of iron, nickel, cobalt, and / or an alloy containing one or more of iron, nickel, and cobalt. The plunger 132 has magnetism, which allows the plunger 132 to translate in the presence of a magnetic field induced by the wire coil 110. The movement of the plunger 132 causes the entire armature assembly 122 to move along the actuation axis 128.

[0028] The contact spring 130 surrounds the support rod 134. The contact spring 130 is located within the contact region 120 between the movable contact 124 and the partition wall 156. In the illustrated embodiment, the contact spring 130 is a coil spring. The contact spring 130 may be compressed between the movable contact 124 and the partition wall 156 to force the movable contact 124 into continuous engagement with the clip 210. The contact spring 130 may directly or indirectly engage the mounting side 204 of the movable contact 124 and may directly or indirectly engage the top side 158 of the partition wall 156. In the illustrated embodiment, the contact spring 130 directly engages the top side 158 of the partition wall 156 and indirectly engages the mounting side 204 of the movable contact 124 via the damper 138. The damper 138 is clamped between the contact spring 130 and the movable contact 124. As described in more detail herein, when the electromechanical switch 101 is Figure 2 in the closed state shown, the damper 138 absorbs and / or dissipates the vibrations and oscillations of the movable contact 124 and / or the contact spring 130 to eliminate or at least suppress the generation of audible noise.

[0029] Figure 2 when the electromechanical switch 101 is in the closed state Figure 1 is a schematic diagram of the power circuit 100 in which the movable contact 124 engages the fixed contacts 108, 109. The closed state is achieved by the armature assembly 122 moving along the actuation axis 128 toward the fixed contacts 108, 109 fromFigure 1 the position movement shown

[0030] The movable contact 124 is conductively coupled to both the fixed contacts 108, 109. The movable contact 124 provides a closed circuit path between the fixed contacts 108, 109. For example, current is allowed to flow between the fixed contacts 108, 109 through the movable contact 124 that forms a conductive bridge. In the illustrated embodiment, in the closed state of the electromechanical switch 101, current from the system power supply 102 is transmitted through the contacts 108, 124, 109 to the electrical load 104 to power the load 104. In response to the armature assembly 122 moving away from the fixed contacts 108, 109, the electromechanical switch 101 can transition to Figure 1 the open state shown, such that the movable contact 124 disengages from the fixed contact 108. This disengagement breaks the circuit and stops the flow of current between the system power supply 102 and the electrical load 104.

[0031] Although two fixed contacts 108, 109 and one movable contact 124 are shown in Figure 1 and Figure 2 , it should be recognized that the electromechanical switch 101 can have a different number of fixed contacts and / or a different number of movable contacts in other embodiments. Additionally, in other embodiments, the electromechanical switch 101 can have a different configuration of fixed contacts and movable contacts. For example, a single movable contact can be permanently fixed to a first fixed contact and can be configured to move relative to a second fixed contact to close and open a circuit between the first fixed contact and the second fixed contact.

[0032] Figure 3 is Figure 1 an enlarged view of a portion of the electromechanical switch 101 in the open state shown. The mating side 202 of the movable contact 124 includes a first contact area 206 and a second contact area 208. The first contact area 206 is aligned with the first fixed contact 108, and the second contact area 208 is aligned with the second fixed contact 109. In the illustrated embodiment, the first contact area 206 is disposed below the first fixed contact 108, and the second contact area 208 is disposed below the second fixed contact 109. To achieve Figure 2 the closed state shown, the armature assembly 122 moves along the actuation axis 128 until the first contact area 206 engages the first fixed contact 108 and the second contact area 208 engages the second fixed contact 109. The first contact area 206 and the second contact area 208 are spaced apart from each other along the width of the movable contact 124. The support bar 134 can be coupled to the movable contact 124 between the first contact area 206 and the second contact area 208. For example, the opening 212 that receives the support bar 134 can be located between the first contact area 206 and the second contact area 208.

[0033] The contact spring 130 is configured to control the spacing between the movable contact 124 and the partition wall 156. For example, the contact spring 130 can force the movable contact 124 to continuously engage between the clip 210 and the mating side 202 of the movable contact 124. The contact spring 130 is engaged by the damper 138. The contact spring 130 extends between the contact end 220 of the spring 130 and the structural end 222 of the spring 130. The contact end 220 is at or near the movable contact 124, and the structural end 222 is at or near the top side 158 of the partition wall 156. In the illustrated embodiment, the contact spring 130 is a helical coil spring that surrounds a section of the support rod 134 between the movable contact 124 and the partition bridge 156.

[0034] The damper 138 has a first side 224 and a second side 226 opposite the first side 224. In the illustrated embodiment, the damper 138 is disposed between the contact spring 130 and the movable contact 124. For example, the first side 224 of the damper 138 engages the contact end 220 of the contact spring 130, and the second side 226 engages the mounting side 204 of the movable contact 124. The damper 138 is sandwiched between the contact spring 130 and the movable contact 124. Due to the forces exerted on the damper 138 by the spring 130 and the movable contact 124, the damper 138 can be at least partially compressed or deformed. The damper 138 absorbs and / or dissipates the vibrations and oscillations of the spring 130 and / or the movable contact 124. In the illustrated embodiment, the damper 138 circumferentially surrounds the support rod 134.

[0035] In the illustrated embodiment, the structural end 222 of the contact spring 130 engages the partition wall 156, and the contact end 220 indirectly engages the movable contact 124 via the damper 138.

[0036] Figure 4 is a perspective view of the damper 138 of the electromechanical switch 101 according to an embodiment. The damper 138 is an O-ring such that the damper 138 has an annular body 230 that defines a central cavity 232. The damper 138 can be loaded onto the support rod 134 (as Figure 3 shown) such that the support rod 134 extends through the central cavity 232. The annular body 230 can have a circular cross-sectional shape (e.g., like a donut), as Figure 4 shown. The damper 138 can be configured to compress and / or deform to assume a flattened state when installed in the electromechanical switch 101. For example, the damper 138 can be in the Figure 3 flattened state shown. In an alternative embodiment, when in the compressed state, the body 230 of the damper 138 can include one or more flat surfaces (e.g., flat surfaces along its first side 224 and second side 226) and curved surfaces between the flat surfaces.

[0037] The damper 138 may include one or more elastic materials. For example, the damper 138 may include thermoplastic elastomers, natural rubber, synthetic rubber, silicone, etc. In a non-limiting example, the elastic material may be or include perfluoroether rubber (FFKM). The elastic material provides the damper 138 with compressible and / or deformable properties, which allows the damper 138 to reduce the vibration and / or oscillation of the contact spring 130 and / or the movable contact 124.

[0038] Figure 5 is an enlarged view of a part of the electromechanical switch 101 in the open state according to an alternative embodiment. The illustrated embodiment is different from Figure 3 the illustrated embodiment in the arrangement of the contact spring 130 and the damper 138 between the movable contact 124 and the partition wall 156. In Figure 5 it, the damper 138 is sandwiched between the contact spring 130 and the partition wall 156. The first side 224 of the damper 138 engages the structural end 222 of the contact spring 130, and the second side 226 of the damper 138 engages the partition wall 156. The damper 138 can absorb the vibration and / or oscillation of the contact spring 130. The damper 138 is spaced apart from the movable contact 124. The contact end 220 of the contact spring 130 can engage the mounting side 204 of the movable contact 124. Optionally, Figure 5 the illustrated damper 138 may be similar in size and / or shape to Figure 3 and Figure 4 the illustrated damper 138.

[0039] In another alternative embodiment, the electromechanical switch 101 may have multiple dampers, including Figure 3 a first damper 130 at the position shown in Figure 5 and a second damper 130 at the position shown in

[0040] Figure 6 is a cross-sectional perspective view of the damper 138 of the electromechanical switch 101 according to an alternative embodiment. In the illustrated embodiment, in the illustrated embodiment, the damper 138 includes an inner lip 302 and an outer lip 304 that protrude beyond the first side 224. The inner lip 302 and the outer lip 304 extend circumferentially along the annular body 230. The outer lip 304 is located at the periphery of the damper 138. The inner lip 302 is radially spaced from the outer lip 304 to define a radial gap 306 therebetween. In an embodiment, an end segment of the contact spring 130 (as Figure 5 shown) is received in the radial gap 306 and engages at least one of the inner lip 302 and the outer lip 304. For example, according to Figure 5 the arrangement shown, the outer lip 304 may engage and surround the structural end 222 of the contact spring 130, or according to Figure 3In the arrangement shown, the outer lip 304 can engage and surround the contact end 220 of the contact spring 130. The lips 302, 304 can enable the damper 138 to be fixed to the contact spring 130 and can enhance the vibration and oscillation of the contact spring 130 and / or the movable contact 124.

[0041] The second side 226 of the damper 138 can be lip-less and can be similar to Figure 4 the second side 226 shown. Although the damper 138 includes an inner lip 302 and an outer lip 304 in the embodiment shown, in an alternative embodiment, the damper 138 can have only the outer lip 304 or only the inner lip 302 instead of both.

[0042] Figure 7 is an enlarged view of a portion of the electromechanical switch 101 in the open state according to another alternative embodiment. Figure 8 is according to Figure 7 the embodiment shown of a perspective view of the damper 138 of the electromechanical switch 101. The damper 138 is Figure 7 and Figure 8 in a hollow tube 310 or sleeve. The hollow tube 310 circumferentially surrounds both the support rod 134 and the contact spring 130. The hollow tube 310 surrounds the contact spring 130 along at least a section of the contact spring 130 between the movable contact 124 and the partition wall 156. In an embodiment where the hollow tube 310 extends the entire length of the contact spring 130, the first end 312 and the second end 314 of the hollow tube 310 can engage the movable contact 124 and the partition wall 156, respectively. Alternatively, one or both of the ends 312, 314 can be spaced apart from the movable contact 124 and / or the partition wall 156. The hollow tube 310 attenuates vibration and / or oscillation along the length of the contact spring 130.

Claims

1. An armature assembly for an electromechanical switch, comprising: A movable contact having a mating side and a mounting side opposite the mating side, the movable contact defining an opening therethrough; A support rod extending through the opening and coupled to the movable contact, the support rod extending through an aperture in a partition wall of the electromechanical switch; A ferromagnetic plunger coupled to the support rod from the movable contact along an opposite side of the partition wall; A contact spring surrounding the support rod between the movable contact and the partition wall; And A damper surrounding the support rod between the movable contact and the partition wall, the damper engaging the contact spring to absorb vibrations along one or more of the contact spring or the movable contact.

2. The armature assembly according to claim 1, wherein the contact spring has a contact end at the movable contact and a structural end at the partition wall, and the damper is clamped between the contact end of the contact spring and the mounting side of the movable contact.

3. The armature assembly according to claim 1, wherein the contact spring has a contact end at the movable contact and a structural end at the partition wall, and the damper is clamped between the structural end of the contact spring and the partition wall.

4. The armature assembly according to claim 1, wherein the damper comprises an elastic material and is compressible.

5. The armature assembly according to claim 1, wherein the damper is a hollow tube and circumferentially surrounds the contact spring along at least a portion thereof between the movable contact and the partition wall.

6. The armature assembly according to claim 1, wherein the damper is an O-ring.

7. The armature assembly according to claim 1, wherein the damper has a first side that engages an end of the contact spring, and the damper includes an outer lip that protrudes beyond the first side along a perimeter of the damper, the outer lip engaging and at least partially surrounding the end of the contact spring.

8. An electromechanical switch, comprising: A housing having a partition wall; A first fixed contact and a second fixed contact mounted to the housing; A movable contact having a mating side facing the first fixed contact and the second fixed contact and a mounting side opposite the mating side; And A carrier sub-assembly configured to move the movable contact relative to the first fixed contact and the second fixed contact, the carrier sub-assembly including: A support rod extending through an aperture in the partition wall and coupled to the movable contact; A contact spring surrounding the support rod between the partition wall and the mounting side of the movable contact; and A damper in the form of an O-ring surrounding the support rod, the damper having a first side that engages an end of the contact spring and a second side opposite the first side that engages the mounting side of the movable contact, wherein the damper comprises an elastic material and is compressible to absorb vibrations along one or more of the contact spring or the movable contact.

9. The electromechanical switch according to claim 8, wherein the carrier subassembly further includes a ferromagnetic plunger that is coupled from the movable contact along opposite sides of the partition wall to the support rod, the ferromagnetic plunger configured to move the carrier subassembly and the movable contact relative to the first fixed contact and the second fixed contact based on the presence or absence of a magnetic field induced by a current through a wire coil surrounding the ferromagnetic plunger.

10. The electromechanical switch according to claim 8, wherein mating sides of the movable contact define first and second contact regions spaced from each other, and in response to the carrier subassembly moving the movable contact into engagement with the first fixed contact and the second fixed contact, the first contact region engages the first fixed contact and the second contact region engages the second fixed contact, wherein the support rod is coupled to the movable contact between the first contact region and the second contact region.

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