Low contact resistance electromechanical switch
By designing textured features on the contact surface of electromechanical switches to form multiple contact points, the problem of high resistance caused by contaminants is solved, achieving the effect of low resistance and high current conduction.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- AMPOMOMAX
- Filing Date
- 2025-11-05
- Publication Date
- 2026-05-08
AI Technical Summary
Contaminants deposited on the contact surface of electromechanical switches can cause a lack of continuity or high resistance, affecting the contact's closing performance.
The interface between the fixed and movable contacts is designed with textured surface features to form multiple contact points, ensuring direct metal-to-metal low-resistance contact even in the presence of contaminants.
It effectively reduces contact resistance, improves the current conduction capability of the contacts, and ensures that an efficient electrical connection can still be maintained in the presence of contaminants.
Smart Images
Figure CN122000244A_ABST
Abstract
Description
Technical Field
[0001] The main topic of this article is electromechanical switches. Background Technology
[0002] Certain electrical applications, such as HVAC, power supply, locomotive, elevator control, motor control, aerospace applications, hybrid electric vehicles, fuel cell vehicles, and charging systems, utilize electromechanical switches, also known as electrical contactors, which have normally open (or open) contacts. The contacts close (or engage) to supply power to a specific device. When the contactor receives an electrical signal, it is energized to introduce a magnetic field that drives the movable contact to engage with the stationary contact. In some cases, contaminants may deposit on one or more of the mating surfaces of the contacts, potentially leading to a "no-contact" (non-functional) or high-resistance condition. Contaminants can also impede contact closure. Contaminants may be generated during assembly, such as being trapped inside the contactor during assembly, or may be generated over time by the degradation of the housing material, resulting in foreign object debris (FOD) deposits potentially settling on the contacts. Summary of the Invention
[0003] In one embodiment, an electromechanical switch is provided, comprising a switch housing having a body forming a chamber. The electromechanical switch includes fixed contacts coupled to the switch housing. Each fixed contact has a mating end located within the chamber and a terminating end outside the switch housing. The fixed contacts have a fixed mating surface at their respective mating ends. The electromechanical switch includes a movable contact within the chamber and movable between an open position and a closed position. The movable contact includes a movable mating surface configured to engage with the fixed mating surface at the mating end of the fixed contact in the closed position. The movable contact is separated from the fixed contact in the open position. The electromechanical switch includes an actuator within the chamber. The actuator includes an armature operably coupled to the movable contact to move the movable contact during operation of the actuator. At least one of the fixed mating surface and the movable mating surface includes a textured surface feature such that the mating interface between the fixed contact and the movable contact each has a plurality of contact points. Attached Figure Description
[0004] The invention will be described by way of example with reference to the accompanying drawings, in which:
[0005] Figure 1 An electromechanical switch according to an exemplary embodiment is shown.
[0006] Figure 2 This is a cross-sectional view of an electromechanical switch according to an exemplary embodiment, showing the internal components of the electromechanical switch.
[0007] Figure 3 A fixed contact according to an exemplary embodiment is shown.
[0008] Figure 4 A movable contact according to an exemplary embodiment is shown.
[0009] Figure 5 A portion of a movable contact according to an exemplary embodiment is shown.
[0010] Figure 6 A portion of an electromechanical switch according to an exemplary embodiment is shown, illustrating a movable contact in the off position.
[0011] Figure 7 A portion of an electromechanical switch according to an exemplary embodiment is shown, illustrating a movable contact in a closed position.
[0012] Figure 8 A portion of an electromechanical switch according to an exemplary embodiment is shown, illustrating contaminants on a movable contact.
[0013] Figure 9 This is a cross-sectional view of a portion of an electromechanical switch in the closed position according to an exemplary embodiment. Detailed Implementation
[0014] Figure 1 An electromechanical switch 100 according to an exemplary embodiment is shown. Figure 2 This is a cross-sectional view of an electromechanical switch 100 according to an exemplary embodiment, showing the internal components of the electromechanical switch 100. The electromechanical switch 100 may be a switch or relay that safely connects and disconnects one or more circuits to protect the electrical flow through the system. The electromechanical switch 100 can be used in a variety of applications, such as HVAC, power supply, locomotive, elevator control, motor control, aerospace applications, hybrid electric vehicles, fuel cell vehicles, charging systems, etc.
[0015] The electromechanical switch 100 includes a housing 110 (in Figure 2 (The internal components of the electromechanical switch 100 are removed to show the internal components of the electromechanical switch 100). The housing 110 has an outer wall 111 surrounding the chamber 112. In various embodiments, the housing 110 may be a multi-piece housing. The housing 110 includes a base 114 and a head 116 extending from the base 114. Optionally, the base 114 may be configured to be coupled to another component. For example, the base 114 may include a mounting bracket for securing the electromechanical switch 100 to another component. In the illustrated embodiment, the base 114 is located at the bottom of the electromechanical switch 100, and the head 116 is located above the base 114; however, in alternative embodiments, the housing 110 may have other orientations. The housing 110 includes a cover 118 for closing the chamber 112. Figure 1For example, a cover 118 may be attached to the top of a head 116. Alternatively, the cover 118 may be sealed to the head 116. In various embodiments, the outer wall 111 of the head 116 may be cylindrical, thereby defining a cylindrical chamber 112. The chamber 112 may be at least partially filled with epoxy resin for sealing the housing 110 and internal components.
[0016] The electromechanical switch 100 includes a first fixed contact 120 and a second fixed contact 122 received in a chamber 112, and a movable contact 124 movable within the chamber 112 between a closed or engaged position and an open or unengaged position. The movable contact 124 is electrically connected to the fixed contacts 120 and 122 in the closed / engaged position. The fixed contacts 120 and 122 are fixed to a housing 110. For example, the fixed contacts 120 and 122 may be coupled to a head 116 and / or a cover 118. In an exemplary embodiment, a contact retainer 126 is used to retain the fixed contacts 120 and 122. The contact retainer 126 is received in the chamber 112 and coupled to the housing 110. The contact retainer 126 can be removed from the chamber 112 when the cover 118 is removed from the head 116. The contact retainer 126 defines a cover 128. The fixed contacts 120 and 122 extend into the cover 128. The movable contact 124 is located within the housing 128. The outer wall 111 surrounds the housing 128.
[0017] The fixed contacts 120 and 122 each include an outer end defining a terminating end 130 and an inner end defining a mating end 132. Each of the fixed contacts 120 and 122 has a transition portion 134 between its ends, which transitions between the interior and exterior of the chamber 112. In the illustrated embodiment, the fixed contacts 120 and 122 are generally cylindrical, for example, comprising one or more cylindrical segments. The terminating end 130 and the mating end 132 may extend along a common longitudinal axis of the fixed contacts 120 and 122. In alternative embodiments, other shapes are possible.
[0018] Termination terminal 130 is configured to terminate to another component, such as a wire or terminal, such as a line input or line output wire. In an exemplary embodiment, termination terminal 130 is exposed outside the electromechanical switch 100 for termination to another component. Termination terminal 130 may be threaded to receive a nut. For example, termination terminal 130 may include a threaded post 136. In the illustrated embodiment, termination terminal 130 extends through and over cover 118. However, termination terminal 130 may have other features for termination to a cable or busbar, such as solder pads.
[0019] The mating end 132 is located within the chamber 112 and is used to connect with the movable contact 124, for example, when the electromechanical switch 100 is energized. In an exemplary embodiment, the mating end 132 includes a mating post 138 having a mating pad at the distal end of the fixed contacts 120, 122. The mating pad may be oriented generally horizontally. The first fixed contact 120 and the second fixed contact 122 respectively include a first fixed mating surface 140 and a second fixed mating surface 142 at their mating ends 132. The movable contact 124 is configured to connect to the fixed contacts 120, 122 at the fixed mating surfaces 140, 142. The fixed mating surfaces 140, 142 of the fixed contacts 120, 122 may be coplanar with each other for mating with the movable contact 124.
[0020] The movable contact 124 includes a contact body 148 extending between a first end 150 and a second end 152. The first end 150 and the second end 152 are configured to mate with a first fixed contact 120 and a second fixed contact 122. The contact body 148 has a central portion 154 between the first end 150 and the second end 152. The movable contact 124 includes a first movable mating surface 160 and a second movable mating surface 162 at the first end 150 and the second end 152. The first movable mating surface 160 and the second movable mating surface 162 are configured to engage with the first fixed mating surface 140 and the second fixed mating surface 142 in a closed position.
[0021] In an exemplary embodiment, the fixed mating surfaces 140, 142 and / or the movable mating surfaces 160, 162 include textured surface features. Figure 3-5 (As shown in the example), to form a mating interface with multiple contact points between fixed contacts 120, 122 and movable contact 124. Textured surface features include surface roughening features such as protrusions, projections, cuts, grooves, peaks, valleys, or other features to roughen, texture, or otherwise non-uniform the surface. Textured surface features form non-planar mating interfaces. For example, textured surface features include protrusions forming peaks defining contact points and grooves between the peaks. Grooves form spaces to receive any contaminants (e.g., plastic particles) and position the contaminants away from the peaks. Peaks protrude beyond (e.g., stand proudly) the contaminants to ensure direct metal-to-metal contact at the contact points of the low-resistance, high-current interface between movable contact 124 and fixed contacts 120, 122. In various embodiments, textured surface features include knurling formed by a knurling process. Textured surface features may be rhomboid. However, textured surface features may have other shapes. Textured surface features have a height above the average grain size. For example, for a grain size of about 40 micrometers, a textured surface feature can have a height of at least 100 micrometers.
[0022] In an exemplary embodiment, the fixed contacts 120 and 122 include textured surface features, while the movable contact 124 does not have textured surface features. For example, the movable contact 124 has a planar surface at the movable mating surfaces 160 and 162. In another exemplary embodiment, the movable contact 124 includes textured surface features, while the fixed contacts 120 and 122 do not have textured surface features. For example, the fixed contacts 120 and 122 may be planar at the fixed mating surfaces 140 and 142. In another exemplary embodiment, the movable contact 124 includes textured surface features at the movable mating surfaces 160 and 162, and the fixed contacts 120 and 122 include textured surface features at the fixed mating surfaces 140 and 142.
[0023] In an exemplary embodiment, the fixed contacts 120 and 122 are made of a first metallic material, and the movable contact 124 is made of a second metallic material different from the first metallic material. The fixed contacts 120 and 122 are made of a material having a first material hardness, and the movable contact 124 is made of a material having a second material hardness different from the first material hardness. In an exemplary embodiment, the first material hardness is harder than the second material hardness.
[0024] In an exemplary embodiment, the first metallic material is copper (or a copper alloy), and the second metallic material is a different copper (or copper alloy). For example, the first metallic material may be a harder copper material, and the second metallic material may be a softer copper material. The softer copper material provides lower resistance at the mating interface compared to the harder copper material. The softer copper material may be more malleable or malleable at the mating interface to conform to the shape of the harder copper material, thereby enhancing the fit (e.g., increasing the contact area and thus reducing contact resistance). The first metallic material may be hard copper, and the second metallic material may be soft copper. In various embodiments, the first metallic material may be one of H04 copper, H03 copper, H02 copper, H01 copper, or H00 copper, which is harder than the second metallic material. The second metallic material may be one of H03 copper, H02 copper, H01 copper, H00 copper, or soft copper, which is softer than the first metallic material. The first metallic material may be tempered copper, and the second metallic material may be tempered copper. The first metal material can be tempered more than the second metal material to form a copper material that is harder than the second metal material.
[0025] The electromechanical switch 100 includes a coil assembly 190 in a chamber 112, which is operated to move a movable contact 124 between an unengaged position and an engaged position. The coil assembly 190 includes a winding or coil 192 wound around a magnetic core 194 to form an electromagnetic field. The coil assembly 190 includes an armature 196 coupled to the core 194. The movable contact 124 is coupled to the armature 196 and is movable with the armature 196 when the coil assembly 190 is operated. The armature 196 may be a plunger movable in a vertical direction. The coil assembly 190 includes a spring 198 for returning the movable contact 124 to the unengaged position when the coil assembly 190 is de-energized. Optionally, the electromechanical switch 100 may include an arc suppressor (not shown) for suppressing arcing in the circuit. The arc suppressor may be located in the chamber 112 of the housing 110. In an exemplary embodiment, the contact holder 126 may be sealed, for example using epoxy resin, and may be filled with an inert gas to suppress electric arc.
[0026] Figure 3 A fixed contact 120 according to an exemplary embodiment is shown. The fixed contact 120 includes an terminating end 130 and a mating end 132. In an exemplary embodiment, the fixed contact 120 includes a textured surface feature 170 at the mating end 132, for example at a fixed mating surface 140.
[0027] The mating end 132 includes a mating post 138, which has a mating pad 139 at the distal end of the fixed contact 120. The mating pad 139 includes a fixed mating surface 140. A textured surface feature 170 is disposed at the mating pad 139. The textured surface feature 170 may substantially or completely cover the mating pad 139. The textured surface feature 170 is formed for contact with the movable contact 124 (in... Figure 2 (As shown in the diagram) a mating interface. Textured surface feature 170 defines a plurality of contact points at the fixed mating surface 140. In an exemplary embodiment, textured surface feature 170 forms a non-planar mating interface.
[0028] In an exemplary embodiment, the textured surface feature 170 includes protrusions 172 forming peaks 174 that define contact points and grooves 176 between the peaks 174. The grooves 176 form spaces to receive any contaminants (e.g., plastic particles) and position the contaminants away from the peaks. The peaks 174 protrude beyond (e.g., protrude from) the contaminants to ensure direct metal-to-metal contact at the contact point of the low-resistance, high-current interface between the movable contact 124 and the fixed contact 120.
[0029] In an exemplary embodiment, the textured surface feature 170 includes knurling 178 formed by a knurling process. The textured surface feature 170 may be rhomboid. However, the textured surface feature 170 may have other shapes. The textured surface feature 170 has a height higher than the average grain size.
[0030] Figure 4 A movable contact 124 according to an exemplary embodiment is shown. The movable contact 124 includes a first mating end 150 and a second mating end 152, the first mating end 150 and the second mating end 152 being configured to respectively engage with a first fixed contact 120 and a second fixed contact 122 (e.g., ...). Figure 2 (As shown) The movable contact 124 includes movable mating surfaces 160, 162 at the first and second mating ends 150, 152.
[0031] In an exemplary embodiment, the movable contact 124 includes a textured surface feature 180 at a first mating end 150 and a second mating end 152 (e.g., at movable mating surfaces 160, 162). The textured surface feature 180 may substantially or completely cover the mating ends 150, 152. The textured surface feature 180 may substantially or completely cover the central portion 154 between the mating ends 150, 152. The textured surface feature 180 forms a mating interface for mating with the fixed contacts 120, 122. The textured surface feature 180 defines a plurality of contact points at the movable mating surfaces 160, 162. In an exemplary embodiment, the textured surface feature 180 forms a non-planar mating interface.
[0032] In an exemplary embodiment, the textured surface feature 180 includes protrusions 182 forming peaks 184 that define contact points and grooves 186 between the peaks 184. The grooves 186 form spaces to receive any contaminants (e.g., plastic particles) and position the contaminants away from the peaks. The peaks 184 protrude beyond (e.g., protrude from) the contaminants to ensure direct metal-to-metal contact at the contact points of the low-resistance, high-current interface between the movable contact 124 and the fixed contacts 120, 122.
[0033] In an exemplary embodiment, the textured surface feature 180 includes knurling 188 formed by a knurling process. The textured surface feature 180 may be rhomboid. However, the textured surface feature 180 may have other shapes. The height of the textured surface feature 180 is greater than the average grain size.
[0034] Figure 5 A portion of a movable contact 124 according to an exemplary embodiment is shown. The movable contact 124 includes a textured surface feature 180. In the illustrated embodiment, the textured surface feature 180 includes ridges 189 formed on the surface, rather than knurling 188 (as shown). Figure 4 (As shown). The protrusion 189 forms a mating interface for engaging with the fixed contacts 120, 122.
[0035] Figure 6 A portion of an electromechanical switch 100 is shown, illustrating a movable contact in the off position. Figure 7 A portion of an electromechanical switch 100 is shown, illustrating a movable contact in the closed position. Figure 8 A portion of an electromechanical switch 100 is shown, which shows contaminants 200 (e.g., plastic particles) on a movable contact.
[0036] By activating coil assembly 190, movable contact 124 can move between an open and closed position. For example, coil 192 is energized to create an electromagnetic field around magnetic core 194, which drives armature 196 in the activation direction (e.g., upward). Armature 196 drives movable contact 124 to the closed position. When coil 192 is de-energized, return spring 198 returns movable contact 124 and armature 196 to the unengaged / open position. Figure 8 As shown, when contaminant 200 is generated in the chamber, contaminant 200 may contaminate the surfaces of the fixed contacts 120, 122 and / or the movable contact 124. Textured surface features (e.g., Figure 3-5 The textured surface features 170, 180 shown can accommodate contaminant 200 by providing contact points that protrude beyond contaminant 200, thereby allowing direct metal-to-metal contact between movable contact 124 and fixed contact 120, 122 even in the presence of contaminant 200.
[0037] Figure 9 This is a cross-sectional view of a portion of the electromechanical switch 100 in the closed position. Figure 9 This demonstrates direct metal-to-metal contact between the movable contact 124 and the fixed contact 120, even in the presence of contaminant 200.
[0038] In the illustrated embodiment, the stationary contact 120 includes a textured surface feature 170 that forms a contact point with the movable contact 124. The textured surface feature 170 includes protrusions 172 forming peaks 174 and grooves 176 between the peaks 174. The grooves 176 form spaces to receive any contaminants 200 (e.g., plastic particles). The peaks 174 protrude beyond the contaminants 200 (e.g., protrude beyond the contaminants 200) to ensure direct metal-to-metal contact at the contact point of the low-resistance, high-current interface between the movable contact 124 and the stationary contact 120. Figure 9 The diagram shows a current flow line 300 to illustrate the flow of current through the textured surface feature 170.
[0039] In an exemplary embodiment, the movable contact 124 is made of a softer metallic material than the fixed contact 120. For example, the movable contact 124 may be soft copper, while the fixed contact 120 may be hard copper. The metallic material of the movable contact 124 has a lower resistance than the metallic material of the fixed contact 120, allowing more current to flow through the interface (e.g., compared to embodiments using contacts made entirely of hard copper). The metallic material of the movable contact 124 can be partially deformed during mating to conform to the shape of the fixed contact 120, which can increase the amount of surface area in direct contact at the mating interface, thereby reducing resistance to allow more current to flow through the interface (e.g., compared to embodiments using contacts made entirely of hard copper).
Claims
1. An electromechanical switch (100), comprising: A switch housing (110) having a body forming a chamber (112); Fixed contacts (120, 122) are connected to the switch housing, each fixed contact having a mating end (132) located in the chamber and an terminating end (130) outside the switch housing, and each fixed contact having a fixed mating surface (140, 142) at the mating end of the corresponding fixed contact. A movable contact (124) is in the chamber and movable between an open position and a closed position, the movable contact including movable mating surfaces (160, 162) configured to engage with the mating end of the fixed contact at the fixed contact in the closed position, the movable contact being separated from the fixed contact in the open position; and An actuator in the chamber, the actuator including an armature (196) operably coupled to the movable contact to move the movable contact during operation of the actuator; At least one of the fixed mating surface and the movable mating surface includes a textured surface feature (170) such that the mating interface between the fixed contact and the movable contact each has a plurality of contact points.
2. The electromechanical switch (100) according to claim 1, wherein at least one of the fixed mating surface (140, 142) and the movable mating surface (160, 162) of the textured surface feature (170) is non-planar.
3. The electromechanical switch (100) according to claim 1, wherein the textured surface feature (170) includes knurling (178).
4. The electromechanical switch (100) according to claim 1, wherein the textured surface feature (170) includes a protrusion forming a peak (174) defining the contact point; and a groove (176) between the peaks.
5. The electromechanical switch (100) according to claim 1, wherein the textured surface feature (170) is rhomboid.
6. The electromechanical switch (100) according to claim 1, wherein the textured surface feature (170) has a height of at least 100 micrometers.
7. The electromechanical switch (100) according to claim 1, wherein the fixed contact (120, 122) includes the textured surface feature (170), and the movable contact (124) does not have a textured surface feature that is planar at the movable mating surface (160, 162).
8. The electromechanical switch (100) according to claim 1, wherein the movable contact (124) includes the textured surface feature (170), and the fixed contact (120, 122) does not have a planar textured surface feature at the fixed mating surface (140, 142).
9. The electromechanical switch (100) according to claim 1, wherein the fixed contacts (120, 122) are made of a first metal material having a first material hardness, and the movable contact (124) is made of a second metal material different from the first metal material having a second material hardness different from the first material hardness.
10. The electromechanical switch (100) according to claim 9, wherein the hardness of the first material is harder than that of the second material.
11. The electromechanical switch (100) according to claim 9, wherein the first metal material is hard copper and the second metal material is soft copper.
12. The electromechanical switch (100) according to claim 9, wherein the first metal material is one of H04 copper, H03 copper, H02 copper, H01 copper or H00 copper, and wherein the second metal material is one of H03 copper, H02 copper, H01 copper, H00 copper or soft copper.
13. The electromechanical switch (100) according to claim 9, wherein the first metal material is tempered copper and the second metal material is tempered copper, wherein the first metal material has a higher degree of tempering than the second metal material.
14. An electromechanical switch (100), comprising: A switch housing (110) having a body forming a chamber (112); Fixed contacts (120, 122) are connected to the switch housing, each fixed contact having a mating end (132) located in the chamber and an terminating end (130) outside the switch housing, the fixed contacts having fixed mating surfaces (140, 142) at the mating ends of the respective fixed contacts, the fixed contacts being made of a first metallic material having a first material hardness; A movable contact (124) is located in the chamber and is movable between an open position and a closed position. The movable contact includes movable mating surfaces (160, 162) configured to engage with the mating end of the fixed contact at the fixed mating surface in the closed position, and to separate from the fixed contact in the open position. The movable contact is made of a second metal material different from the first metal material of the fixed contact, and the second metal material has a second material hardness different from the first material hardness. and An actuator in the chamber, the actuator including an armature (196) operatively coupled to the movable contact to move the movable contact during operation of the actuator.
15. The electromechanical switch (100) according to claim 14, wherein the first material is harder than the second material.
16. The electromechanical switch (100) according to claim 14, wherein the first metal material is hard copper and the second metal material is soft copper.
17. The electromechanical switch (100) according to claim 14, wherein the first metal material is one of H04 copper, H03 copper, H02 copper, H01 copper or H00 copper, and wherein the second metal material is one of H03 copper, H02 copper, H01 copper, H00 copper or soft copper.
18. The electromechanical switch (100) according to claim 14, wherein the first metal material is tempered copper and the second metal material is tempered copper, wherein the first metal material has a higher degree of tempering than the second metal material.
19. The electromechanical switch (100) according to claim 14, wherein at least one of the fixed mating surfaces (140, 142) and the movable mating surfaces (160, 162) includes a textured surface feature (170) such that the mating interface between the fixed contact (120, 122) and the movable contact (124) each has a plurality of contact points.
20. An electromechanical switch (100), comprising: A switch housing (110) having a body forming a chamber (112); Fixed contacts (120, 122) are connected to the switch housing, each fixed contact having a mating end (132) located in the chamber and an terminating end (130) outside the switch housing, the fixed contacts having fixed mating surfaces (140, 142) at the mating ends of the respective fixed contacts, the fixed contacts being made of a first metallic material having a first material hardness; A movable contact (124) is located in the chamber and is movable between an open position and a closed position. The movable contact includes movable mating surfaces (160, 162) configured to engage with the mating end of the fixed contact (140, 142) at the closed position. The movable contact is separated from the fixed contact at the open position. The movable contact is made of a second metal material different from the first metal material of the fixed contact, and the second metal material has a second material hardness different from the hardness of the first material. and An actuator in the chamber, the actuator including an armature (196) operably coupled to the movable contact to move the movable contact during operation of the actuator; At least one of the fixed mating surface and the movable mating surface includes a textured surface feature, such that the mating interface between the fixed contact and the movable contact each has a plurality of contact points.