High-voltage contactor or high-voltage relay

Abstract

The present application relates to a high voltage contactor (10) or a high voltage relay, comprising: an electromagnetic actuator (112) having a coil (114) disposed on a bobbin (116) and a movable armature (122); a housing (58) having an actuator housing part (60) and an actuator housing cover (80), the actuator (112) being arranged in the housing (58); a contact bridge (44) drivable by the electromagnetic actuator (112) to displace within the contact cavity (42), the first contact element (54) being electrically connected through the contact bridge (44) to the second contact element (56) when displaced to a first position, and the electrical contact between the first contact element (54) and the second contact element (56) being interrupted when displaced to a second position. Wherein the armature (122) is slidably guided in a ferromagnetic guide sleeve (34), the guide sleeve (34) being provided with an axial groove (341) and being arranged inside the electromagnetic actuator (112); the coil framework (116) is provided with a first axial stop piece (32), and the guide sleeve (34) abuts against the first axial stop piece (32) at the first limit position. The actuator housing cover (80) is provided with a second axial stop (36) against which the guide sleeve (34) abuts in a second limit position. The axial stops (32, 36) can prevent excessive axial movement of the guide sleeve (34) after unexpected loosening.

Description

Technical Field

[0001] This application relates to an electromagnetic switching device, and more particularly to a high-voltage contactor or high-voltage relay with an electromagnetic actuator. Background Technology

[0002] These high-voltage contactors are used to connect and disconnect electrical connections under no-load or load conditions, where the voltage may exceed 1000 V and the current may exceed 1000 A under load conditions. For example, this may occur between the traction battery and the drive motor of a battery-powered electric vehicle, or between a charging station and the traction battery.

[0003] Such high-voltage contactors are typically equipped with electromagnetic actuators, for example, as described in DE 10 2018 222 610 A1. The actuator disclosed in this document is part of a hydraulic valve and is typically equipped with an armature that is axially moved from a first non-operating position to a second operating position by means of an excitation coil. For this purpose, the armature is supported and guided in a guide sleeve disposed within a through-hole in the coil frame. The guide sleeve has an axially extending groove that forms a fluid connection between the two end faces of the sleeve. Due to the presence of this groove, the guide sleeve, which is typically pressed into the coil frame or yoke, may loosen and unexpectedly slip axially relative to the core in the coil frame, leading to magnetic circuit failure.

[0004] Therefore, the purpose of this application is to provide a high-voltage contactor or high-voltage relay that is suitable for applications with slotted guide sleeves, and which requires a relatively small number of components in terms of actuator design, thus being particularly cost-effective to manufacture and easy to assemble, while avoiding magnetic circuit failure. Summary of the Invention

[0005] This objective is achieved by a high-voltage contactor or high-voltage relay having the features described in claim 1.

[0006] The high-voltage contactor or high-voltage relay according to this application is equipped with an electromagnetic actuator by which the contactor can be switched. The term "electromagnetic actuator" refers to all actuators that generate motion based on electromagnetic force. Therefore, the electromagnetic actuator particularly includes a coil—which comprises a coil frame and windings wound thereon, a magnetic circuit around the coil, and an armature movable by electromagnetic force, the armature being arranged inside the coil and the magnetic circuit.

[0007] For the sake of brevity, the term "high-voltage contactor" will be used only below, but it also refers to "high-voltage relay".

[0008] In addition, the terms radial, axial, and diametrical directions refer to the central axis of the high-voltage contactor, along which the armature of the actuator is movable.

[0009] The high-voltage contactor includes a housing with an internal contact cavity, which may be multi-piece and is preferably made of plastic. The housing includes an actuator housing component and an actuator housing cover that encloses the actuator housing component. An electromagnetic actuator is arranged within and protected by the actuator housing component from the intrusion of dust or moisture from the environment.

[0010] The high-voltage contactor is also equipped with a first contact element and a second contact element fixedly connected to the housing. These extend into the contact cavity and are connected to two busbars outside the high-voltage contactor, one of which is connected to the battery, and the other, for example, to a drive motor, or to a charging station and vehicle battery. An electrical connection between these two contact elements is established via a contact bridge, which is driven to displacement within the contact cavity by an actuator. Through an excitation winding, the contact bridge (which may have electrical contacts at both ends) typically moves axially and abuts against the two contact elements on the housing, thereby placing the contact bridge in a first position, through which an electrical connection is formed between the first and second contact elements. For this purpose, the contact bridge is functionally connected to the armature (e.g., via a push rod), and the movement of the armature under electromagnetic force is pressed against the contact elements. To disconnect this electrical connection, the contact bridge is biased in the opposite direction, typically by a spring force acting on the armature, rotor, or contact bridge in the opposite direction to the electromagnetic force, thereby displacing the contact bridge to a second position, at which point the electrical connection between the first and second contact elements is severed.

[0011] The armature is supported and guided within a guide sleeve. The guide sleeve is arranged such that energizing the coil surrounding the armature allows axial movement of the armature, thereby driving a contact bridge connected to a push rod against a contact element on the housing side. The guide sleeve is made of a ferromagnetic material and has an axial groove extending axially from a first axial end face to a second axial end face. The guide sleeve is disposed inside the actuator, for example, axially fixed by pressing it into the actuator's mounting base. Due to the presence of this groove, the diameter of the guide sleeve may vary slightly, and it may accidentally loosen due to thermal or mechanical effects, resulting in axial slippage.

[0012] To avoid this, the coil frame is provided with a first axial stop, against which the guide sleeve abuts at a first extreme position. The first axial stop is arranged on the axial side of the guide sleeve facing the contact cavity, thus limiting the displacement of the guide sleeve toward the contact cavity. Furthermore, the actuator housing cover is provided with a second axial stop, against which the guide sleeve abuts at a second extreme position. The second axial stop is arranged on the axial side of the guide sleeve facing away from the contact cavity, thus limiting the displacement of the guide sleeve away from the contact cavity. In the fixed state, the guide sleeve will be positioned between the two axial stops without contacting them. However, if the guide sleeve becomes loose, its movement will be limited by the housing cover (made of non-magnetic plastic) and the axial stops on the coil frame, thus reliably preventing any interference with the magnetic circuit. Similarly, the guide sleeve can also be positioned in the fixed state, abutting against one of the two axial stops.

[0013] Therefore, the axial stop ensures that the guide sleeve can only be displaced by a few millimeters after loosening. In addition, the ferromagnetic guide sleeve has relatively low magnetic reluctance, so that the magnetic field is only slightly weakened when penetrating the guide sleeve, thus the actuator has particularly high performance.

[0014] In a particularly preferred embodiment of this application, the coil bobbin has a central opening in which a guide sleeve is disposed, wherein a first axial stop is formed by a tapered reduction in the inner diameter of the opening. The central opening can be formed, for example, by a cylindrical hole extending axially through the coil bobbin. Due to the tapering of the inner diameter, a step is formed on the inner wall, which the guide sleeve axially contacts when it becomes loose, thereby restricting its movement in the axial direction. Therefore, the first axial stop is particularly easy to manufacture. Preferably, the tapering is located on the axial side of the guide sleeve facing the contact cavity.

[0015] Preferably, the electromagnetic actuator includes a coil, a magnetic circuit surrounding the coil, and an armature. This allows for the manufacture of an actuator capable of strictly translating motion, eliminating the need for motion conversion. Such an actuator can be manufactured in a particularly compact and cost-effective manner.

[0016] Furthermore, it is advantageous that the magnetic path consists of a back magnetic plate and a U-shaped magnetic yoke, with the free end of the yoke abutting against the back magnetic plate. The magnetic yoke can be made by simple bending, while the flat back magnetic plate acts as a support surface during the overmolding process to form an axial contact cavity wall.

[0017] In another particularly preferred embodiment of this application, the guide sleeve is pressed into a mounting base of the yoke, preferably cylindrical. This ensures direct magnetic contact between the yoke and the guide sleeve, which facilitates the generation of a relatively strong magnetic field for moving the armature. Due to thermal or mechanical shock, the guide sleeve may accidentally loosen from its press-fit in the yoke mounting base and slide axially. This can occur, for example, when the frictional force between the armature and the guide sleeve is greater than that between the yoke and the guide sleeve. The diameter of the coil frame is a few tenths of a millimeter larger than the guide sleeve to facilitate press-fitting and ensure that the press-fit is formed only between the yoke and the guide sleeve. Upon loosening, the guide sleeve can therefore move relatively easily within the coil frame. An axial stop reliably restricts this axial movement and allows only slight movement of the guide sleeve.

[0018] In another particularly preferred embodiment of this application, the actuator housing cover has an annular protrusion that forms a second axial stop. This protrusion is a wall segment that projects axially toward the guide sleeve relative to the main body of the actuator housing cover, wherein the outer diameter of the wall segment is greater than or equal to the outer diameter of the guide sleeve, and the inner diameter of the wall segment is less than or equal to the inner diameter of the guide sleeve. This stop prevents the guide sleeve from moving too far and dislodging from the coil bobbin.

[0019] In another advantageous embodiment of this application, the axial movement of the armature is restricted in the second axial direction by the second axial stop. Therefore, the second axial stop (e.g., it can be defined as an annular protrusion on the actuator housing cover) not only restricts the axial displacement of the guide sleeve but also restricts the axial displacement of the armature in the direction away from the contact cavity. For this purpose, the outer diameter of the annular protrusion is greater than or equal to the outer diameter of the guide sleeve, and the inner diameter of the protrusion is smaller than the outer diameter of the armature. Therefore, a single axial stop can be used for both the guide sleeve and the armature, resulting in a cost advantage.

[0020] In a further embodiment of this application, the armature is biased against a second axial stop by a return spring in the non-switching state. The non-switching state is defined as the armature being in its non-operating position and the contact bridge not in contact with the contact element. In this state, the coil is not energized, and therefore no electromagnetic force acts on the armature. After the electromagnetic actuator is turned off, the return spring moves the armature from the switching position (the position where the contact bridge contacts the contact element) back to the non-operating position and holds the armature in its non-operating position. Tensing the armature against the stop in particular prevents accidental movement of the armature in the guide sleeve, which, under strong mechanical impact (e.g., when a vehicle drives over a cobblestone road), could cause unintended contact between the contact bridge and the contact element, resulting in unintended circuit closure. Furthermore, noise emissions are avoided.

[0021] In another particularly advantageous embodiment of this application, the actuator housing component is manufactured using a plastic overmolded actuator. This design completely shields the actuator from the contact cavity and the environment, except for a small opening into the contact cavity through which the push rod extends. Due to the overmolding, the manufacturing process is significantly simplified, as fewer individual components need to be assembled and manufactured. Simultaneously, the required space is reduced by eliminating the gaps that would otherwise be necessary between housing components, and by reducing manufacturing costs compared to conventional designs. Furthermore, a robust system is created in which the actuator cannot move within the housing. Additionally, acoustic emissions are reduced by avoiding a resonant cavity between the actuator and the housing.

[0022] Preferably, during overmolding, the magnetic circuit of the electromagnetic actuator is completely covered radially inside and outside, while the magnetic circuit is defined axially by the axial contact cavity wall of the actuator housing component in the axial direction toward the contact cavity. Thus, the actuator is defined radially outward toward the contact cavity on one side, and the magnetic circuit is defined radially relative to the coil by the plastic. The plastic fills the gap between the coil winding and the magnetic circuit, thus preventing relative movement between them. Any contact between the magnetic circuit and the winding is prevented because the plastic of the actuator housing is radially arranged between the magnetic circuit and the coil, and axially arranged in the coil frame between the winding and the magnetic circuit. This produces a virtually gapless actuator housing with high strength and a small wall thickness, thus reliably preventing leakage.

[0023] Accordingly, the back magnet is axially arranged between the coil or coil frame and the axial contact cavity wall, and contacts the axial contact cavity wall, thus eliminating the need for additional components. Furthermore, the back magnet, preferably made of metal, further reinforces the axial contact cavity wall.

[0024] Furthermore, advantageously, the actuator housing component extends at least radially outward, covering the outermost portion of the actuator, on its axially outer side facing away from the contact cavity, and has an opening on its radially inner portion, which is completely closed by an actuator housing cover, preferably made of plastic. Therefore, after overmolding, the guide sleeve can still be axially inserted into the coil frame from this outer side, and the armature can be inserted into the sleeve. However, this provides high strength and complete sealing towards the outside of the housing, thus preventing contamination from the outside or outward venting.

[0025] In a further embodiment, the actuator housing cover is circumferentially attached to the actuator housing component in a material bonding manner, particularly by adhesive bonding, laser welding, ultrasonic welding, or rotational vibration welding. This attachment is highly durable and completely sealant, requiring no additional seals.

[0026] In another advantageous embodiment of this application, the guide sleeve is made of sheet metal material by rolling. This allows the guide sleeve to be inexpensively manufactured from simple metal strips.

[0027] An embodiment of the high-voltage contactor or high-voltage relay according to this application is shown in the accompanying drawings and described below. Attached Figure Description

[0028] Figure 1 A side sectional view of a high-voltage contactor according to an embodiment of this application is shown.

[0029] Figure 2 This application shows the Figure 1 Enlarged cross-sectional view of the actuator section of a medium- and high-voltage contactor.

[0030] Figure 3 This application shows the Figure 1 Perspective view of the guide sleeve used in medium and high voltage contactors. Detailed Implementation

[0031] Figure 1 The high-voltage contactor 10 or high-voltage relay shown includes an electromagnetic actuator 112 equipped with a coil 114 (consisting of a coil frame 116 and a coil winding 118 wound thereon), a ferromagnetic circuit 120, and an armature 122. The ferromagnetic circuit 120 includes a U-shaped magnetic yoke 124, the end 126 of which abuts against or is attached to a back magnetic plate 128, thereby defining a closed magnetic circuit 120.

[0032] The yoke 124 has a central opening 132 in its base portion 130, the diameter of which substantially corresponds to the inner diameter of the coil frame 116. A guide sleeve 34 is fixedly mounted in this opening 132 or inside the coil frame 116, and the armature 122 is displaceably arranged and guided in the guide sleeve 34. When current flows through the coil 114, the armature 122 is pulled toward the back magnet 128 against the force of the return spring 136 in a known manner.

[0033] A push rod 12 abuts axially against an armature 122, the push rod 12 extending into a contact cavity 42 through another central opening 40 on a back magnet plate 128.

[0034] The push rod 12 is pushed against the armature 122 of the actuator 112 by a return spring 136, which is designed as a helical compression spring and located in the contact cavity 42. The return spring 136 axially abuts against a shoulder flange 13 of the push rod 12 and is supported on the axially opposite side by a contact cavity cover 88, which axially closes the contact cavity 42. The first contact element 24 of the contact bridge 20 is axially arranged opposite to the first housing-side contact element 54, which can be connected to a high-voltage battery (particularly via a busbar not shown). The second contact element 26 of the contact bridge 20 is arranged opposite to the second housing-side contact element 56, which can be connected, for example, to the drive motor of a motor vehicle via a busbar.

[0035] The contact bridge 20 abuts against the flange 13 in the axial direction with its first axial end face facing the flange 13. A contact spring 30 is arranged on the end face of the contact bridge 20 facing the actuator 112, and the contact spring 30 abuts against the end face of the contact bridge 20 facing the actuator 112.

[0036] On the axial side of the contact spring 30 facing away from the contact bridge 20, the contact spring 30 abuts against a disc-shaped retaining element 16, which is fixedly connected to the push rod 12. Therefore, the contact spring 30 is axially arranged between the retaining element 16 and the contact bridge 20, and biases the contact bridge 20 in the axial direction. The contact spring 30 also has a central cylindrical opening 39 through which it is mounted on the push rod 12. Therefore, the push rod 12 axially passes through the contact bridge 20, the contact spring 30, and the retaining element 16.

[0037] The entire high-voltage contactor 10 is housed in a housing 58, which comprises three parts. The actuator 112 is overmolded with plastic to form the housing component 60. This plastic completely radially surrounds the coil 114 to define a radial boundary wall 66 and also fills the space 68 between the coil 114 and the yoke 124. Furthermore, the yoke 124 itself is completely radially encased by this plastic, thus shielding it from the environment. Additionally, the back magnet 128 (which abuts against the coil frame 116 on the coil frame side) is axially covered by this plastic in the direction toward the contact cavity 42, thereby defining an axial contact cavity wall 69.

[0038] Furthermore, a circumferential radial contact cavity wall 86 extends from the back magnet plate 128 in the extension of the plastic surrounding the actuator 112, and this radial contact cavity wall 86 radially defines the contact cavity 42. The radial contact cavity wall 86 is also integrally defined with the axial contact cavity wall 69 and is manufactured during the overmolding process of the actuator 112, thereby forming the four sidewalls of the contact cavity 42 in this embodiment.

[0039] On the axially outer side 72 of the actuator housing component 60 opposite to the contact cavity 42, the plastic extends further radially inward along the radially outer portion 74 of the yoke 124 or actuator 112, leaving an opening 78 only in the central radially inner region 76. This opening 78 is concentrically defined with the cylindrical mounting base 132 of the yoke 124, but with a slightly larger diameter to allow sufficient space for the insertion of the guide sleeve 34.

[0040] The opening 78 is closed by an actuator housing cover 80, which is attached to the opening 78 of the actuator housing component 60 by means of material bonding (particularly by laser welding, ultrasonic welding or rotary vibration welding).

[0041] The slotted guide sleeve 34 is made of ferromagnetic material and is pressed into the mounting base 132 of the yoke 124. Due to thermal and / or mechanical stress, the guide sleeve 34 may accidentally loosen from its press fit in the mounting base 132 of the yoke 124. To prevent damage caused by such loosening, the coil frame 116 is provided with a first axial stop 32 against which the guide sleeve 34 abuts at a first extreme position. The stop is formed by a stepped tapering of the internal opening 117 of the coil frame 116. The first axial stop 32 is arranged on the side of the guide sleeve 34 facing the contact cavity 42 axially and restricts the axial displacement of the guide sleeve 34 toward the contact cavity 42. The actuator housing cover 80 is provided with a second axial stop 36 against which the guide sleeve 34 abuts at a second extreme position. The second axial stop 36 is formed by an annular protrusion 82 that extends axially from the body 81 of the actuator housing cover 80 toward the guide sleeve 34 and restricts the axial displacement of the guide sleeve 34 in the direction opposite to the contact cavity 42. Furthermore, in the non-operating state (when the coil 114 is not energized), the armature 122 abuts against the second axial stop 36 and is pressed against it by the return spring 136. For this purpose, the annular protrusion 82 extends radially inward beyond the inner diameter of the guide sleeve 34.

[0042] Furthermore, the housing component 60 manufactured by overmolding the actuator 12 defines a structure in the form of a plug housing 82 through which the connecting wire 84 of the winding 18 of the coil 14 is guided to the outside, thereby providing an electrical connection of the coil 14 to a voltage source through a plug counterpart.

[0043] The contact cavity 42 is closed by a contact cavity cover 88 on its axial side opposite to the axial contact cavity wall 69. Two axial openings 90 are defined on the contact cavity cover 88, in which two contact elements 54, 56 are received and fixed, for example by ultrasonic welding or overmolding. An outer wall 92 extends circumferentially from the contact cavity cover 88, surrounding the radial contact cavity wall 86 of the actuator housing component 60, such that the two walls 86, 92 can be circumferentially connected to each other, for example by laser welding, ultrasonic welding, or rotational vibration welding, thereby producing a high-strength housing 58.

[0044] To activate the current flow between the motor or charging station and the battery, coil 114 is energized, causing armature 122 to be pulled towards back magnet 128 by the electromagnetic force acting upon it. This switches the high-voltage contactor 10 to the ON state, in which push rod 12, along with contact bridge 20 and contact bridge-side contact elements 24, 26, are pushed towards housing-side contact elements 54, 56, allowing current to flow through contact bridge 20 from first contact element 54 to second contact element 56, and thus from the battery to the motor or from the charging station to the battery. The travel dimension of armature 122 is designed such that, in the ON state, the contact bridge is lifted from end stop 13 on push rod 12, causing the spring force of contact spring 30 to press contact bridge-side contact elements 24, 26 against housing-side contact elements 54, 56. If coil 114 is not energized, push rod 12 and armature 122 are biased in opposite directions by spring 136, causing contact bridge 20 to lift from contact elements 54, 56, and the circuit is broken.

[0045] Due to this movement of the armature 122 and any possible vibration or thermal effects, the guide sleeve 34 may become loose. However, its movement is restricted by the plastic actuator housing cover 80 and the plastic coil frame 116, which ensures that the contactor function is fully maintained and prevents any impact on the electromagnetic circuit despite the use of the ferromagnetic guide sleeve 34.

Claims

1. A high-voltage contactor (10) or high-voltage relay, comprising: - an electromagnetic actuator (112) having a coil (114) arranged on a coil former (116) and a movable armature (122), - a housing (58) having an actuator housing part (60) and an actuator housing cover (80), the actuator (112) being arranged in the housing (58), - a contact bridge (44) which can be driven by the actuator (112) to be displaced within a contact chamber (42), when displaced into a first position a first contact element (54) is electrically connected to a second contact element (56) by the contact bridge (44), when displaced into a second position the electrical contact between the first contact element (54) and the second contact element (56) is interrupted, characterized in that - the armature (122) is slidably guided in a ferromagnetic guide sleeve (34), the guide sleeve (34) is provided with an axial slot (341) and is arranged inside the actuator (112), and - the coil former (116) is provided with a first axial stop (32), against which the guide sleeve (34) abuts in a first limit position, the actuator housing cover (80) is provided with a second axial stop (36), against which the guide sleeve (34) abuts in a second limit position.

2. The high voltage contactor (10) or high voltage relay according to claim 1, characterized in that - the coil former (116) is provided with a central opening (117), in which the guide sleeve (34) is arranged, wherein the first axial stop (32) is formed by a tapering of the inner diameter of the opening (117).

3. The high voltage contactor (10) or high voltage relay according to claim 1 or 2, characterized in that - the electromagnetic actuator (112) is provided with a magnetic circuit (120) surrounding the coil (114).

4. The high voltage contactor (10) or high voltage relay according to claim 3, characterized in that - the magnetic circuit (120) is composed of a back yoke (128) and a U-shaped yoke (124), the free end (126) of the yoke (124) abutting against the back yoke (128).

5. The high voltage contactor (10) or high voltage relay according to claim 4, characterized in that - the guide sleeve (34) is pressed into a mounting seat (132) of the yoke (124).

6. The high voltage contactor (10) or high voltage relay according to any of the preceding claims, characterized in that - the actuator housing cover (80) is provided with an annular protrusion (82), by which the second axial stop (36) is formed.

7. The high voltage contactor (10) or high voltage relay according to any of the preceding claims, characterized in that - the movement of the armature (122) in the second axial direction of the contact chamber (42) is limited by the second axial stop (36).

8. The high voltage contactor (10) or high voltage relay according to claim 7, characterized in that - in a non-switching state the armature (122) is biased against the second axial stop (36) by a return spring (136).

9. High voltage contactor (10) or high voltage relay according to any of the preceding claims, characterized in that - the actuator housing part (60) is manufactured by overmolding the actuator (112) using plastic.

10. The high voltage contactor (10) or high voltage relay according to any one of claims 3 to 9, characterized in that - the magnetic circuit (120) is completely wrapped by the actuator housing part (60) manufactured by overmolding radially inside and outside and is delimited in the axial direction towards the contact chamber (42) by an axial contact chamber wall (69).

11. The high voltage contactor (10) or high voltage relay according to claim 10, characterized in that - the back yoke (128) is arranged axially between the coil (114) and the axial contact chamber wall (69) and abuts against the axial contact chamber wall (69).

12. High voltage contactor (10) or high voltage relay according to any of the preceding claims, characterized in that The actuator housing part (60) extends at least over a radially outer portion (74) of the actuator (112) on its axial outer side (72) facing away from the contact chamber (42) and is provided with an opening (78) in its radially inner portion (76), which opening (78) is completely closed by the actuator housing cover (80).

13. High voltage contactor (10) or high voltage relay according to any of the preceding claims, characterized in that The actuator housing cover (80) is attached to the actuator housing part (60) in a materially bonded manner in the circumferential direction.

14. High voltage contactor (10) or high voltage relay according to any of the preceding claims, characterized in that The guide sleeve (34) is made of sheet metal material by means of rolling.

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