High-voltage contactor or high-voltage relay

Abstract

The invention relates to a high-voltage contactor (10) or high-voltage relay comprising: an electromagnetic actuator (112) having a coil (114) arranged on a coil carrier (116) and a movable armature (112); a housing (58) having an actuator housing part (60) and an actuator housing cover (80) in which the actuator (112) is arranged; a contact bridge (44) which can be displaced in a contact chamber (42) by means of the actuator (112) at least into a first position in which a first contact element (54) is electrically connected to a second contact element (56) via the contact bridge (44), and into a second position in which electrical contact between the first contact element (54) and the second contact element (56) is interrupted, wherein the armature (120) is slidingly guided in a ferromagnetic guiding sleeve (34) that has an axial slot (341) and is arranged inside the actuator (112), and the coil carrier (116) has a first axial stop (32) against which the guiding sleeve (34) rests in a first end position, and the actuator housing cover (80) has a second axial stop (36) against which the guiding sleeve (34) rests in a second end position. The axial stops (32, 36) prevent the guiding sleeve (34) from moving excessively in the axial direction in the event of unintended loosening.

Description

[0001] DESCRIPTION

[0002] High-voltage contactor or high-voltage relay

[0003] The invention relates to a high-voltage contactor or high-voltage relay with an electromagnetic actuator.

[0004] Such high-performance switching devices are required to be able to establish and disconnect electrical connections in no-load conditions and under load conditions, where voltages of over 1000 V and currents of over 1000 A may be present, for example, in electrically powered vehicles between the battery and the drive motor or between a charging station and the battery.

[0005] Such a high-voltage contactor frequently comprises an electromagnetic actuator, as disclosed, for example, in DE 10 2018 222 610 A1. The actuator disclosed in this document is part of a hydraulic valve and typically comprises an armature that is axially moved from a first rest position to a second switched-on position by energizing a coil. For this purpose, the armature is mounted and guided in a guide bushing arranged within a through-opening of the coil carrier. The guide bushing has an axially extending slot that creates a fluidic connection between the two end faces of the bushing. Due to the gap, the guide bushing, which is typically pressed into the coil carrier or yoke, can become loose and unintentionally slip axially against the core in the coil carrier, disrupting the function of the magnetic circuit.The present invention is therefore based on the object of creating a high-voltage contactor or high-voltage relay that is suitable for use with a slotted guide bushing and that, with regard to the structural design of the actuator, requires a relatively small number of components and is therefore particularly cost-effective to manufacture and easy to install. Malfunctions of the magnetic iron circuit are to be avoided.

[0006] This object is achieved by a high-voltage contactor or high-voltage relay having the features of claim 1.

[0007] The high-voltage contactor or high-voltage relay according to the invention has an electromagnetic actuator via which the contactor can be switched. An electromagnetic actuator is understood to mean all actuators that generate movement due to a force caused by electromagnetism. The electromagnetic actuator thus consists in particular of a coil consisting of a coil carrier and a winding wound thereon, as well as an armature arranged within the coil that can be moved due to the electromagnetic force.

[0008] For the sake of simplicity, only the term high-voltage contactor is used below, which also includes the term high-voltage relay.

[0009] Furthermore, the terms radial, axial and diametrical refer to the central axis of the high-voltage contactor along which the armature of the actuator can be moved.

[0010] The high-voltage contactor comprises a housing with an internal contact chamber, which can be constructed in several parts and is preferably made of plastic. The housing comprises an actuator housing part and an actuator housing cover that closes the actuator housing part. The actuator is arranged in the actuator housing part and is protected by it from the ingress of dirt or moisture from the environment.

[0011] The high-voltage contactor further comprises a first and second contact element fixedly mounted on the housing. These contact elements protrude into the contact chamber and are connected outside the high-voltage contactor to two busbars, one of which leads to the battery and the other, for example, to the drive motor or which is connected to a charging station and the vehicle's battery. An electrical connection between these two contact elements can be established via a contact bridge connected to an actuating element that is moved along a motion axis in the contact chamber by the actuator.Typically, by applying current to the winding, the contact bridge, at the ends of which two electrical contacts may be formed, is axially displaced toward the two contact elements attached to the housing, in order to establish an electrical connection between the first contact element and the second contact element via the contact bridge in a first position. The actuating element is operatively connected to the armature of the actuator and is pressed against the contact elements by the movement of the armature due to the electromagnetic force.To open this electrical connection, the contact bridge is loaded in the opposite direction, which is usually achieved by means of a spring force acting on the armature or the contact bridge opposite to the electromagnetic force, so that the contact bridge is moved to a second position in which electrical contact between the first contact element and the second contact element is interrupted.

[0012] The armature is slidably guided in a guide bushing which is arranged in such a way that the armature can be moved in the axial direction by energizing the coil surrounding the armature in order to move the contact bridge connected to the actuating element against the contact elements on the housing. The guide bushing is made of a ferromagnetic material and has an axial slot which runs in the axial direction from the first axial end face to the second axial end face of the guide bushing. The guide bushing is arranged inside the actuator and is pressed into a receptacle in the actuator for axial fixation, for example. Due to the slot, the diameter of the guide bushing can vary slightly and can become unintentionally loose due to thermal or mechanical influences, which can cause the guide bushing to slip in the axial direction.

[0013] To prevent this, the coil carrier has a first axial stop against which the guide bush rests in a first end position. The first axial stop is arranged on the axial side of the guide bush facing the contact chamber, such that the first axial stop limits displacement of the guide bush in the direction of the contact chamber. Furthermore, the actuator housing cover has a second axial stop against which the guide bush rests in a second end position. The second axial stop is arranged on the axial side of the guide bush facing away from the contact chamber, such that the second axial stop limits displacement of the guide bush away from the contact chamber. In the fixed state, the guide bush is arranged between the two axial stops without touching them.However, if the guide bushing becomes loose, its movement is restricted by the axial stops on the housing cover, made of non-magnetic plastic, and on the coil carrier to such an extent that disruption of the magnetic circuit is reliably prevented. The guide bushing can also be positioned in a fixed position so that it rests against one of the two axial stops.

[0014] The axial stops ensure that the guide bushing can only be moved a few millimeters after loosening. Furthermore, a ferromagnetic guide bushing has a relatively low magnetic resistance, which means that the magnetic field is only slightly weakened when passing through the guide bushing, thus ensuring particularly high performance.

[0015] In a particularly preferred embodiment of the invention, the coil carrier has a central opening in which the guide bushing is arranged, wherein the first axial stop is formed by a taper of the inner diameter of the opening. The central opening can, for example, be formed by a cylindrical bore axially penetrating the coil carrier. The taper of the inner diameter forms a step on the inner wall against which the guide bushing axially abuts when it is released, so that its movement in the axial direction is limited. The first axial stop is therefore particularly easy to manufacture. The taper is preferably located on the axial side of the guide bushing facing the contact chamber.

[0016] The electromagnetic actuator advantageously has an iron circuit surrounding the coil. This creates a purely translational actuator that eliminates the need for motion conversion. Such an actuator can be manufactured particularly small and cost-effectively.

[0017] Furthermore, it is advantageous if the iron circuit is formed from a return plate and a U-shaped yoke, the free legs of which rest on the return plate. The yoke can be manufactured accordingly by simple bending, while the straight return plate serves as a support surface during overmolding to form an axial contact chamber wall that separates the actuator from the contact chamber. In another particularly preferred embodiment of the invention, the guide bushing is pressed into a receptacle of the yoke, which is preferably cylindrical. This ensures direct magnetic contact between the yoke and the guide bushing, which promotes the generation of a relatively strong magnetic field for moving the armature. Due to thermal or mechanical influences, the guide bushing can unintentionally become detached from the press fit in the yoke receptacle and slip axially.This occurs, for example, when the frictional force between the armature and the guide bushing is greater than the frictional force between the yoke and the guide bushing. The coil carrier has a diameter a few tenths of a millimeter larger than the guide bushing to facilitate pressing in and ensure that the press connection exists only between the yoke and the guide bushing. Consequently, once loosened, the guide bushing can move relatively easily within the coil carrier. The aforementioned axial stops reliably limit this axial movement and allow only minimal movement of the guide bushing.

[0018] In another particularly preferred embodiment of the invention, the actuator housing cover has an annular projection forming the second axial stop. The projection is a wall section raised axially in the direction of the guide bushing relative to the base body of the actuator housing cover, whose outer diameter is greater than or equal to the outer diameter of the guide bushing and whose inner diameter is less than or equal to the inner diameter of the guide bushing. This stop prevents the guide bushing from disengaging too far from the coil carrier.

[0019] In a further advantageous embodiment of the invention, the axial movement of the armature is limited in the second axial direction by the second axial stop. The second axial stop, which can be designed, for example, as an annular projection on the actuator housing cover, thus serves, in addition to limiting the axial displacement of the guide bush, to limit the axial displacement of the armature in the direction opposite to the contact chamber. For this purpose, the outer diameter of the annular projection is greater than or equal to the outer diameter of the guide bush, and the inner diameter of the projection is smaller than the outer diameter of the armature. Thus, one axial stop can be used for both the guide bush and the armature, resulting in a cost advantage.

[0020] In a further embodiment of the invention, the armature is biased against the second axial stop by a return spring in a non-switched state. The non-switched state describes the state in which the armature is in its rest position and in which the contact bridge is not in contact with the contact elements. In this state, the coil is not energized, so no electromagnetic force acts on the armature. After the electromagnetic actuator is switched off, the return spring moves the armature from the switched position, in which the contact bridge rests against the contact elements, back to the rest position and holds the armature in its rest position.By clamping the armature against the stop, it is prevented from accidentally moving in the guide bushing, which, under strong mechanical influences, such as driving over cobblestones, can lead to unwanted contact between the contact bridge and the contact elements, thus closing the circuit. Furthermore, noise is avoided.

[0021] In a further particularly advantageous embodiment of the invention, the actuator housing part is manufactured by overmolding the actuator with plastic. This design completely shields the actuator from the contact chamber and the environment, with the exception of the small opening through which the actuating element protrudes into the contact chamber. Overmolding significantly simplifies production, as fewer individual parts are required and must be assembled. Furthermore, the space requirement is reduced by eliminating the otherwise necessary clearance between the housing parts, as well as the manufacturing costs compared to known designs. In addition, a stable system is created in which the actuator cannot move within the housing. Furthermore, acoustic emissions are reduced by avoiding resonance cavities between the actuator and the housing.

[0022] Preferably, the iron circuit of the electromagnetic actuator is also completely overmolded radially inside and out during the overmolding, while the iron circuit is axially limited in the direction of the contact chamber by the axial contact chamber wall of the actuator housing part. This means that the actuator is radially outwardly limited to the contact chamber on the one hand, and the iron circuit is radially limited opposite the coil by the plastic. The plastic fills the gap between the coil winding and the iron circuit, so that relative movement to each other is also excluded here. Contact between the iron circuit and the winding is prevented because the plastic of the actuator housing is arranged radially between the iron circuit and the coil, and the coil carrier is arranged axially between the winding and the iron circuit. This creates an almost gap-free actuator housing with high strength and low wall thickness. Leaks are thus reliably prevented.

[0023] The return plate is preferably arranged axially between the coil or coil carrier and the axial contact chamber wall and rests against the axial contact chamber wall, eliminating the need for additional components. Furthermore, the return plate, which is preferably metallic, further reinforces the axial contact chamber wall.

[0024] Furthermore, it is advantageous if the actuator housing part, on its axial outer side opposite the contact chamber, extends at least over a radially outer region of the actuator and has an opening in the radially inner region that is completely closed by the actuator housing cover, which is preferably made of plastic. Accordingly, after overmolding, the guide bushing can still be inserted into the coil carrier and the armature inserted into the bushing in the axial direction from this outer side. Nevertheless, high strength and complete sealing of the housing to the outside are achieved, thus preventing external contamination or outgassing.

[0025] In a further embodiment, the actuator housing cover is attached to the actuator housing part all the way around, particularly by adhesive bonding, laser welding, ultrasonic welding, or rotational vibration welding. This attachment is highly durable and completely leak-proof, without the need for additional seals.

[0026] In a further advantageous embodiment of the invention, the guide bushing is made of sheet metal by means of rollers. This allows the guide bushing to be manufactured cost-effectively from a simple sheet metal strip.

[0027] An embodiment of a high-voltage contactor or high-voltage relay according to the invention is shown in the figures and is described below.

[0028] Figure 1 shows a side view of a high-voltage contactor according to the invention according to a first embodiment in a sectional view.

[0029] Figure 2 shows an enlarged view of the actuator of the high-voltage contactor according to the invention in Figure 1. Figure 3 shows a perspective view of the guide bushing of the high-voltage contactor according to the invention in Figure 1.

[0030] The high-voltage contactor 10 shown in Figure 1 comprises an electromagnetic actuator 112 having a coil 114 consisting of a coil carrier 116 and a winding 118 wound thereon, a ferromagnetic iron circuit 120, and an armature 122. The ferromagnetic iron circuit 120 has a U-shaped yoke 124, the legs 126 of which rest on a return plate 128 or are attached to the return plate 128, thus forming the closed iron circuit 120.

[0031] The yoke 124 has a central opening 132 at its base portion 130, the diameter of which essentially corresponds to the inner diameter of the coil carrier 116. A guide bushing 34 is arranged in this opening 117, or rather, inside the coil carrier 116, in which the armature 122 is slidably mounted and guided. When current is applied to the coil 114, the armature 122 is drawn toward the return plate 128 in a known manner against the force of a return spring 136.

[0032] The actuating element 12 rests axially on the armature 122 and projects through a central opening 40 in the return plate 128 into a contact chamber 42. The actuating element 12 is pressed against the armature 122 of the actuator 112 by the return spring 136, which is designed as a helical compression spring and is arranged in the contact chamber 42. The return spring 136 rests axially on a collar-like flange 13 of the actuating element 12 and is supported on the axially opposite side on a contact chamber cover 88 which axially closes the contact chamber 42. The first contact element 24 of the contact bridge 20 is arranged axially opposite a first housing-side contact element 54, which can be connected to a high-voltage battery, in particular via a busbar (not shown).The second contact element 26 of the contact bridge 20 is arranged opposite a second housing-side contact element 56, which can be connected, for example, via a busbar to a drive motor of a motor vehicle.

[0033] The contact bridge 20 rests against the flange 13 in the axial direction with a 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, which contact spring rests against the end face of the contact bridge 20 facing the actuator 112.

[0034] On the axial side of the contact spring 30 opposite the contact bridge 20, the contact spring 30 rests against a disk-like retaining element 16, which is firmly connected to the actuating element 12. The contact spring 30 is thus arranged axially between the retaining element 16 and the contact bridge 20 and prestresses the contact bridge 20 in the axial direction. The contact spring 30 further has a central cylindrical opening 39, by means of which the contact spring 30 is plugged onto the actuating element 12. The actuating element 12 thus extends axially through the contact bridge 20, the contact spring 30, and through the retaining element 16.

[0035] The entire high-voltage contactor 10 is arranged in a housing 58, which is composed of a total of three parts. The actuator 112 is overmolded with a plastic to form an actuator housing part 60. This plastic completely surrounds the coil 114 radially to form a radial boundary wall 66 and also fills a gap 68 radially between the coil 114 and the yoke 124. In addition, the yoke 124 itself is completely surrounded radially by this plastic and is thus shielded from the environment. Furthermore, the return plate 128, which bears against the coil carrier 116 on its side facing the coil carrier 116, is covered axially by this plastic in the direction of the contact chamber 42 and forms an axial contact chamber wall 69.

[0036] In addition, a circumferential radial contact chamber wall 86 extends from the return plate 128 as an extension of the plastic surrounding the actuator 112, radially delimiting the contact chamber 42. The radial contact chamber wall 86 is also formed integrally with the axial contact chamber wall 69 and is manufactured during the overmolding of the actuator 112, thus forming four side walls of the contact chamber 42 in the present embodiment.

[0037] On the axial outer side 72 of the actuator housing part 60 opposite the contact chamber 42, the plastic extends further radially inward along a radially outer region 74 of the base part 130 of the yoke 124 or of the actuator 112 and leaves an opening 78 free only in the central, radially inner region 76, which opening is concentric to the cylindrical receptacle 132 of the yoke 124, but has a somewhat larger diameter so that there is sufficient space for inserting the guide bush 34.

[0038] This opening 78 is closed by an actuator housing cover 80, which is fastened to the actuator housing part 60 in the opening 78 in a material-to-material manner, in particular by laser welding, ultrasonic welding or rotational vibration welding.

[0039] The slotted guide bushing 34 is made of a ferromagnetic material and pressed into the receptacle 132 of the yoke 124. Due to thermal and / or mechanical stress, the guide bushing 34 can unintentionally become detached from the press fit in the receptacle 132 of the yoke 124. To prevent damage caused by this loosening, the coil carrier 116 has a first axial stop 32, against which the guide bushing 34 rests in a first end position and which is formed by a stepped taper of the opening 117 inside the coil carrier 116. The first axial stop 32 is arranged on the side of the guide bush 34 axially facing the contact chamber 42 and limits the axial displacement of the guide bush 34 in the direction of the contact chamber 42. The actuator housing cover 80 has a second axial stop 36 against which the guide bush 34 rests in a second end position.The second axial stop 36 is formed by an annular projection 82, which extends axially from the base body 81 of the actuator housing cover 80 toward the guide bushing 34 and limits the axial displacement of the guide bushing 34 in the direction opposite to the contact chamber 42. In addition, in the rest state, in which the coil 114 is not energized, the armature 122 rests against the second axial stop 36 and is pressed against the second axial stop 36 by the return spring 136. For this purpose, the annular projection 82 extends radially inward beyond the inner diameter of the guide bushing 34.

[0040] Furthermore, the actuator housing part 60 produced by overmolding the actuator 112 forms a molding 82 in the form of a plug housing 82, through which the connecting lines to the winding 118 of the coil 114 are led outwards, so that the electrical connection of the coil 114 to a voltage source can be established via a plug counterpart.

[0041] The contact chamber 42 is axially closed on the axial side opposite the axial contact chamber wall 69 by the contact chamber cover 88. Two axial openings 90 are formed on the contact chamber cover 88, in which the two contact elements 54, 56 are received and secured, for example, by ultrasonic welding or overmolding. An outer wall 92 extends circumferentially in the axial direction from this contact chamber cover 88 and encloses the radial contact chamber wall 86 of the actuator housing part 60, so that these two walls 86, 92 can be joined together circumferentially in a materially bonded manner, for example, by laser welding, ultrasonic welding, or rotational vibration welding, thereby creating a high-strength housing 58.

[0042] If the current flow between the electric motor or the charging station and the battery is to be enabled, the coil 114 is energized, pulling the armature 122 toward the return plate 128 due to the acting electromagnetic forces. This causes the high-voltage contactor 10 to switch to the switched state, in which the actuating element 12 with the contact bridge 20 and the contact elements 24, 26 on the contact bridge side is pushed against the housing-side contact elements 54, 56, so that a current can flow via the contact bridge 20 from the first contact element 54 to the second contact element 56 and thus from the battery to the electric motor or from the charging station to the battery.The stroke of the armature 122 is dimensioned such that, in the switched state, the contact bridge lifts off the end stop 13 on the actuating element 12, so that the spring force of the contact spring 30 presses the contact bridge-side contact elements 24, 26 against the housing-side contact elements 54, 56. If the coil 114 is not energized, the actuating element 12 and the armature 122 are loaded in the opposite direction by the spring 136, so that the contact bridge 20 is lifted off the contact elements 54, 56 and the circuit is interrupted.

[0043] Due to this movement of the armature 122 and any vibrations or thermal influences that may occur, the guide bushing 34 may become loose. However, its movement is restricted by the plastic actuator housing cover 80 and the plastic coil carrier 116 to such an extent that the function of the contactor is fully maintained and, despite the use of a ferromagnetic guide bushing 34, any influence on the electromagnetic circuit is prevented.

Claims

P A T E N T A N S P R Ü C H E 1. High-voltage contactor (10) or high-voltage relay with an electromagnetic actuator (112) with a coil (114) arranged on a coil carrier (116) and a movable armature (122), a housing (58) with an actuator housing part (60) and an actuator housing cover (80) in which the actuator (112) is arranged, a contact bridge (44) which is displaceable by means of the actuator (112) in a contact chamber (42) at least into a first position in which a first contact element (54) is electrically connected to a second contact element (56) via the contact bridge (44), and is displaceable into a second position in which an electrical contact between the first contact element (54) and the second contact element (56) is interrupted, wherein the armature (120) is slidably guided in a ferromagnetic guide bushing (34) having an axial slot (341) which is arranged within the actuator (112), and the coil carrier (116) has a first axial stop (32),against which the guide bush (34) rests in a first end position and the actuator housing cover (80) has a second axial stop (36) against which the guide bush (34) rests in a second end position., 2. High-voltage contactor (10) or high-voltage relay according to claim 1, characterized in that the coil carrier (116) has a central opening (117) in which the guide bush (34) is arranged, wherein the first axial stop (32) is formed by a taper of the inner diameter (d) of the opening (32).

3. High-voltage contactor (10) or high-voltage relay according to claim 1 or 2, characterized in that the electromagnetic actuator (112) has an iron circuit (120) surrounding the coil (114).

4. High-voltage contactor (10) or high-voltage relay according to claim 3, characterized in that the iron circuit (120) is formed from a return plate (128) and an I-shaped yoke (124), the free legs (126) of which rest on the return plate (128).

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

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

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

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

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

10. High-voltage contactor (10) or high-voltage relay according to one of claims 3-9, characterized in that the iron circuit (120) of the electromagnetic actuator (112) is completely surrounded radially inside and outside by the actuator housing part (60) produced by overmolding and is surrounded axially in the direction of the contact chamber (42) by an axial contact chamber wall (69).

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

12. High-voltage contactor (10) or high-voltage relay according to one of the preceding claims, characterized in that the actuator housing part (60) extends on its axial outer side (72) opposite the contact chamber (42) at least over a radially outer region (74) of the actuator (112) and in the radial inner region (76) has an opening (78) which is completely closed by the actuator housing cover (80).

13. High-voltage contactor (10) or high-voltage relay according to one of the preceding claims, characterized in that the actuator housing cover (80) is circumferentially secured to the actuator housing part (60) in a materially bonded manner.

14. High-voltage contactor (10) or high-voltage relay according to one of the preceding claims, characterized in that the guide bushing (34) is made of sheet metal by means of rollers.

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