High-voltage contactor or high-voltage relay

Abstract

High-voltage contactors (10) or high-voltage relays are known which comprise: an electromagnetic actuator (12) which has a movable armature (22); a housing (58) which delimits an internal contact chamber (42); a first contact element (54) which projects into the contact chamber (42); a second contact element (56) which projects into the contact chamber (42); an actuating rod (38); a contact bridge (44) which is arranged on the actuating rod (38), said contact bridge being movable together with the armature (22) and the actuating rod (38), by means of the actuator (12), at least into a first position in which the first contact element (54) is electrically connected to the second contact element (56) via the contact bridge (44), and being movable together with the armature (22) and the actuating rod (38), by means of a spring element (36), into a second position in which electrical contact between the first contact element (54) and the second contact element (56) is interrupted; and a rod head (48), which is formed on the opposite end of the actuating rod (38) in relation to the armature (22). In order to avoid a hard impact between the rod head (48) and the contact bridge (44) upon separation of the electrical contacts, it is proposed that the actuating rod (38) is loaded against the armature (22) by means of the spring element (36), and an elastic element (76) is arranged between the contact bridge (44) and the rod head (48).

Description

[0001] DESCRIPTION

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

[0003] The invention relates to a high-voltage contactor or high-voltage relay with an electromagnetic actuator having a movable armature, a housing which defines an inner contact chamber, a first contact element which projects into the contact chamber, a second contact element which projects into the contact chamber, an actuating rod, a contact bridge which is arranged on the actuating rod and which is displaceable with the armature and the actuating rod by means of the actuator at least into a first position in which the first contact element is electrically connected to the second contact element via the contact bridge, and which is displaceable with the actuating rod and the armature via a spring element into a second position in which an electrical contact between the first contact element and the second contact element is interrupted, and a rod head which is formed on the side of the actuating rod opposite the armature.

[0004] Such high-performance switching devices are needed to establish and disconnect electrical connections in both no-load and load situations, where voltages exceeding 1000 V and currents exceeding 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 is known, for example, from EP 3 157 038 Bl. Contact is established by transferring the switching force generated by the electromagnetic actuator via the armature to the actuating rod and from there to the contact bridge. In this state, the contact force is transferred from the actuating rod to the contact bridge via a spring. In the closed state, where the contact bridge rests on the contact elements, an air gap of a few tenths of a millimeter is created between the rod head and the contact bridge.

[0006] When the contactor is switched off and the contacts subsequently open, the actuating rod is pushed back into its starting position by the leaf spring and the additional spring element. Since this separation must occur as quickly as possible, requiring high accelerations of the actuating rod and the contact bridge, high forces are generated when the contact points are reached. This high-force separation is also necessary because, when the contact bridge makes contact with the contact elements, the armature should ideally be in contact with the core or the backplate to generate a high holding force. However, this leads to the armature sticking, which in turn results in a high release force and thus high accelerations. Consequently, after passing through the air gap, the rod head strikes the contact bridge. Since both parts are made of metal, this impact is very hard, resulting in very high contact forces.

[0007] This can result in the drive pin breaking in the area of ​​the spring element's support, the connection between the actuating rod and the spring element's support tearing, the contact bridge being bent by up to a few tenths of a millimeter over time, or the rod head digging into the contact bridge, causing copper abrasion, which can reduce the required leaf spring preload to the point of total failure.

[0008] The challenge therefore lies in reducing the forces occurring in the area of ​​the bearing surfaces between the axial holding elements during separation. At the same time, the axial installation space should be as small as possible and the guard should be designed to be insensitive to wear.

[0009] This problem is solved by a high-voltage contactor or high-voltage relay having the features of main claim 1.

[0010] The high-voltage contactor or high-voltage relay according to the invention comprises an electromagnetic actuator by means of which the contactor can be switched. An electromagnetic actuator is understood to be any actuator that generates movement due to a force caused by electromagnetism. The electromagnetic actuator thus consists, in particular, of either a coil comprising a coil former and a winding wound thereon, an iron core surrounding the coil, and an armature movable by virtue of the electromagnetic force, which is arranged within the coil and the iron core. The high-voltage contactor further comprises a multi-part housing that delimits an inner contact chamber. This housing can, for example, include an actuator housing section with a radial boundary wall that completely surrounds the coil of the electromagnetic actuator radially, so that the coil is radially completely enclosed.The terms radial and axial refer to the central axis of the actuator.

[0011] The high-voltage contactor also has a first and second contact element fixed to the housing, which 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 are connected to a charging station and the vehicle's battery.

[0012] Furthermore, the high-voltage contactor has an actuating rod which is designed to be motion-coupled to the armature and thus moves with it. A rod head is formed at the end opposite the armature.

[0013] An electrical connection between the two contact elements can be established via a contact bridge mounted on the actuating rod, which is moved within the contact chamber by the actuator. Typically, energizing the winding of the armature causes the actuating rod, and consequently the contact bridge, to move axially. Two electrical contacts can be formed at the ends of the contact bridge. The contact bridge, or rather its contacts, are moved axially against the two contact elements attached to the housing by the movement, thus establishing an electrical connection between the first and second contact elements via the contact bridge in a first position.To open this electrical connection and separate the contact bridge from the contact elements, the contact bridge, and with it the armature and the actuating rod, is loaded in the opposite direction, which is achieved by means of a spring force of a spring element that acts on the armature, the actuating rod, the rod head or the contact bridge opposite to the electromagnetic force, so that the contact bridge is moved into a second position in which an electrical contact between the first contact element and the second contact element is interrupted.

[0014] According to the invention, the actuating rod is biased against the anchor via the spring element, thus eliminating the need for a rigid connection at this position and significantly simplifying valve assembly. Furthermore, an elastic element is arranged between the contact bridge and the rod head. This elastic element dampens the pressure surge between the rod head and the contact bridge. This reduces the forces occurring at the contact surface between the rod head and the contact bridge, as well as at the contact surface of the spring element that biases the contact bridge towards the contact elements, since the acceleration of the rod head towards the contact bridge, and thus the impact force acting there, is significantly reduced. In this way, damage or wear to the contact bridge and the actuating rod can be almost completely eliminated.

[0015] Preferably, the elastic element is a spring. Such springs can be designed with any desired spring characteristic, so that the acting braking force can be precisely adjusted.

[0016] In a further embodiment, the spring is designed as a spring disc, which allows the required axial installation space to be kept very small while still generating sufficient spring force.

[0017] The spring washer is advantageously made from spring steel. This provides excellent spring action and durability despite its extremely low thickness.

[0018] It is particularly preferred if the spring washer has a radially outer bearing surface arranged opposite the contact bridge, a radially inner bearing surface arranged opposite the contact bridge, and a central bearing surface arranged radially between the radially outer and inner bearing surfaces, and opposite the rod head. This grooved design of the spring washer allows for the generation of various non-linear spring characteristics.

[0019] In a further embodiment, the axial distance between the radially inner contact surface and the central contact surface is smaller than the distance between the radially outer contact surface and the central contact surface. This means that the spring plate initially rests only on the outer surface of the contact bridge. As a result, upon contact with the rod end of the actuating rod, the spring characteristic is initially relatively soft. Only after this axial spring height is reduced by, for example, about half the spring travel, does the inner contour of the spring plate also contact the upper surface of the contact bridge, thereby significantly increasing the spring rate. This allows the initial force impulse to be absorbed very smoothly. Larger force impulses are absorbed by the second stage at the latest. A non-linear spring characteristic is created, resulting in a gentle deceleration at first.A harsh impact that still occurs is prevented by the second part of the spring travel, even under very high accelerations.

[0020] In a further embodiment, the absolute angle between a radially outer spring section, extending from the radially outer contact surface to the central contact surface, and a line parallel to the axis of symmetry of the spring disc is smaller than the absolute angle between a radially inner spring section, extending from the radially inner contact surface to the central contact surface, and a line parallel to the axis of symmetry of the spring disc. Accordingly, the spring resistance during deformation as the spring passes through the radially outer section and before the second contact surface makes contact with the contact bridge is significantly lower than when passing through the second section. Thus, a gentle deceleration occurs initially, while in the second section, the high spring resistance reliably prevents a hard impact.

[0021] Preferably, the spring element is arranged in the contact chamber and biases the rod end in the direction of the armature. This allows the electromagnet to be made relatively small. Attaching the actuating rod to the armature is unnecessary. In a further advantageous embodiment, a clamping disc is arranged axially on the actuating rod between the contact bridge and the armature, and a shaped leaf spring is clamped axially between the clamping disc and the contact bridge. The outwardly pointing spring arms of the leaf spring are biased against the contact bridge, and its radially inner section rests against the clamping disc. The contact bridge is biased in the direction of the rod end by the leaf spring. This arrangement of the leaf spring allows the force to act directly on the area of ​​the contact bridge opposite the contact elements, thus increasing the contact force in this area.Such a high-voltage contactor can be manufactured with large tolerances due to the generation of the contact force by the leaf spring, while reducing wear.

[0022] The contact chamber is preferably bounded by the housing in the direction of the actuator and has a central guide section in which the actuating rod is guided. Such complete encapsulation of the contact chamber allows the arc generated during opening to be extinguished without any gas escaping. Furthermore, the actuating rod, although not directly connected to the armature, is reliably guided without the need for additional components.

[0023] The armature of such a high-voltage contactor advantageously rests against a core or a backplate of the electromagnetic actuator in the first position, thus generating a very high holding force. Consequently, very high contact forces are also achieved, reliably preventing unintentional opening of the electrical circuit.

[0024] Such a high-voltage contactor or high-voltage relay therefore has a long service life, as damage from impact forces is prevented. At the same time, high holding forces are achieved. The additional elastic element reduces the impact of the rod head on the contact bridge when opening, thus preventing potential breakage of the actuating rod or cracks in the weld seam between the actuating rod and the clamping disc, as well as deformation of the contact bridge and reducing copper abrasion between the rod head and the contact bridge.

[0025] An embodiment of a high-voltage contactor or high-voltage relay according to the invention is shown in the figures and is described below.

[0026] Figure 1 shows a side view of a high-voltage contactor according to the invention in a cutaway view.

[0027] Figure 2 shows a perspective view of the elastic element according to the invention from Figure 1.

[0028] Figure 3 shows a cutaway side view of the elastic element according to the invention from Figure 2.

[0029] Figure 4 shows a resulting spring characteristic curve of the elastic element according to the invention from Figure 2.

[0030] The high-voltage contactor 10 shown in Figure 1 consists of an electromagnetic actuator 12 comprising a coil 14, which in turn consists of a coil carrier 16 and a winding 18 wound on it, a ferromagnetic iron circuit 20, and an armature 22. The ferromagnetic iron circuit 20 has a U-shaped yoke 24, the legs 26 of which rest on or are attached to a backplate 28, thus forming the closed iron circuit 20. The yoke 24 has a central opening 32 at its base 30, the diameter of which corresponds essentially to the inner diameter of the coil carrier 16. A bushing 34 is mounted in this opening 32, or inside the coil carrier 16, in which the armature 22 is slidably arranged and guided. When current is applied to the coil 14, the armature 22 is pulled towards the return plate 28 in a known manner.If the current is interrupted, the armature is pushed away from the return plate 28 by means of the force of a spring element 36.

[0031] An actuating rod 38 rests against the armature 22 and projects through a further central opening 40 in the return plate 28 into a contact chamber 42. A contact bridge 44 is arranged at the end of the actuating rod 38 opposite the armature 22. This bridge is preferably pressed against a rod head 48 at the end of the actuating rod 38 by means of a leaf spring 46. The rod head 48 is supported by a clamping disc 50, which is attached to the actuating rod 38 and is thus arranged to be axially and tiltably movable on the actuating rod 38. A contact plate 52, 53, made of a particularly conductive material, is attached to each end of the contact bridge 44. The first contact plate 52 is arranged axially opposite a first contact element 54, which can be connected to a high-voltage battery, in particular via a busbar (not shown).The second contact plate 53 is arranged opposite a second contact element 56, which can be connected, for example, to a drive motor of a motor vehicle via a busbar. The contact bridge 44 is tensioned in the direction of the contact elements 54 and 56, or in the direction of the rod end 48, by means of spring arms 55 of the leaf spring 46.

[0032] The entire high-voltage contactor 10 is arranged in a housing 58, which is composed of three parts, as can be seen particularly in Figure 1. The actuator 12 is overmolded with a plastic to form an actuator housing part 60. This plastic completely surrounds the coil 14 radially and also fills a radial gap between the coil 14 and the yoke 24. Additionally, the yoke 24 itself is completely surrounded radially by this plastic and is thus shielded from the environment. Furthermore, the backplate 28, which rests against the coil carrier 16 on its side facing the coil carrier 16, is axially covered by this plastic in the direction of the contact chamber 42 and forms an axial boundary wall 62.From this boundary wall 62, a central guide section 64 extends into the contact chamber 42 and into the opening 40 of the backplate 28, so that the latter is covered radially inwards by the plastic, forming a central guide opening inside in which the actuating rod 38 is guided.

[0033] On the axial outer side of the actuator housing part 60 opposite the contact chamber 42, the plastic extends further radially inwards in a radially outer area of ​​the base part 30 of the yoke 24 or of the actuator 12, leaving only an opening in the central, radially inner area, which is symmetrical to the opening 32, but has a slightly larger diameter to provide sufficient space for pressing in the bushing 34.

[0034] This opening is closed by a plastic cover 65, which is attached to the actuator housing part 60 in the opening by means of a material bond, in particular by laser welding, ultrasonic welding or rotary vibration welding.

[0035] In addition, a circumferential housing wall 66 extends from the backplate 28 in extension of the plastic surrounding the actuator 12, which radially limits the contact chamber 42 and is also manufactured in one piece during the overmolding of the actuator 12 and thus forms four side walls of the contact chamber 42 in the present embodiment.

[0036] The contact chamber 42 is closed axially on the axial side opposite the axial boundary wall 62 by a switching housing part 68. Two axial openings are formed in the switching housing part 68, in which the two contact elements 54, 56 are received and attached, for example, by ultrasonic welding or overmolding. An outer wall 70 extends circumferentially in the axial direction from this lid-shaped switching housing part 68, enclosing the circumferential housing wall 66 of the actuator housing part 60, so that these two walls 66, 70 are joined circumferentially, for example, by welding.

[0037] laser welding, ultrasonic welding or rotary vibration welding can be combined to create a high-strength housing 58.

[0038] The spring element 36 is supported on the switch housing part 68 and is centrally located between the two contact elements 54, 56. The opposite end of the spring element 36 is biased against the rod head 48, so that the actuating rod 38 is pressed towards the armature 22, thus ensuring that it bears constant contact against the armature 22. An inner annular projection 72 is formed on the rod head 48, extending into the interior of the spring element 36, thereby securing the spring element 36 radially to the rod head 48.

[0039] To enable current flow between the electric motor or charging station and the battery, the coil 14 is energized, causing the armature 22 to be pulled towards the return plate 28 by the electromagnetic forces. This pushes the actuating rod 38, and via the tension disc 50 and the leaf spring 46, also the contact bridge 44 with the contact plates 52, 53, against the contact elements 54, 56, so that current can flow via the contact bridge 44 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. In this state, a gap of a few tenths of a millimeter is created between the contact bridge 44 and a surface 74 of the rod head 48 facing the contact bridge 44.

[0040] When the current to coil 14 is interrupted, the actuating rod 38 and the armature 22 are biased in opposite directions by the spring element 36. This not only pushes the actuating rod 38 against the armature 22, causing it to detach from the return plate 28 and move towards the plastic cover 65, thus lifting the contact bridge 44 from the contact elements 54, 56 and interrupting the circuit, but also accelerates the rod head 48 towards the contact bridge 44. This typically results in a hard stop after passing through the gap between the contact bridge 44 and the surface 74 of the rod head 48 facing the contact bridge 44, which can lead to damage.

[0041] For this reason, an elastic element 76 in the form of a spring washer 78 is arranged axially between the surface 74 of the rod head 48 facing the contact bridge 44 and the contact bridge 44, radially surrounding the actuating rod 38.

[0042] This spring washer 78, made from a thin sheet of spring steel, is shown in Figures 2 and 3. It has a radially outer bearing surface 80, with which the spring washer 78 rests on the contact bridge 44. From this surface, a radially outer spring section 82 extends radially inwards, forming an angle of more than 45°, in particular approximately 60°, with a line parallel to the axis of symmetry. This means that the radial extent of this radially outer spring section 82 is greater than its axial extent. The radially outer spring section 82 extends to a radially central bearing surface 84, with which the spring washer 78 bears against the surface 74 of the rod head 48 facing the contact bridge 44. From here, the spring washer 78 extends again in a radially inner spring section 86 in the opposite direction, i.e., towards the contact bridge 44, to a radially inner bearing surface 88.The angle of this radially inner spring section 86 to a line parallel to the axis of symmetry can be chosen to be somewhat smaller than its axial extent, so that, compared to the radially outer spring section 82, it has a smaller radial extent for the same axial extent. In particular, the axial extent of this radially inner spring section 86 is smaller than the axial extent of the radially outer spring section 82, so that in the relaxed state, the spring washer 78 rests only on the radially outer contact surface 80 on the contact bridge 44 and on the surface 74 of the rod head 48 facing the contact bridge 44 with its radially central contact surface 84, while the radially inner contact surface 88 is arranged at a distance from the contact bridge.

[0043] This results in the following: when the coil 14 is energized and the rod head 48 moves towards the contact bridge 44, the spring disc 78 is initially compressed in its radially outer spring section 82, in which the spring disc 78 exhibits a relatively flat spring characteristic 90 with a spring rate of, for example, 1200 N / mm, as can be seen in Figure 4. As soon as the spring disc 78 is compressed to the point that the radially inner contact surface 88 also comes into contact with the contact bridge 44, both spring sections 82, 86 begin to act, and the compression resistance of the spring disc increases considerably, resulting in a significantly steeper spring characteristic 92 with a spring rate of, for example, 3600 N / mm.The smaller the radial extent of the radially inner spring section 86 is compared to its radial extent, the steeper this spring characteristic curve 92 becomes, which, however, also becomes significantly steeper through the engagement of the radially inner spring section 86 if both spring sections 82, 86 are designed with the same slope.

[0044] Accordingly, the relative speed between the contact bridge 44 and the rod end 48 is initially gently decelerated, and this deceleration is subsequently significantly increased by the steeper spring characteristic 92, thus reliably preventing the rod end 48 from impacting the contact bridge 44 with a hard stop. This reliably reduces damage or wear to the actuating rod, the clamping disc, the rod end, and the contact bridge, thereby preventing the high-voltage contactor from failing due to this force impulse.

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 (12) having a movable armature (22), a housing (58) which defines an inner contact chamber (42), a first contact element (54) which projects into the contact chamber (42), a second contact element (56) which projects into the contact chamber (42), an actuating rod (38), a contact bridge (44) which is arranged on the actuating rod (38) and which is displaceable with the armature (22) and the actuating rod (38) by means of the actuator (12) at least into a first position in which the first contact element (54) is electrically connected to the second contact element (56) via the contact bridge (44), and which is displaceable with the actuating rod (38) and the armature (22) via a spring element (36) into a second position in which an electrical contact between the first contact element (54) and the second contact element (56) is interrupted is, a rod head (48),which is formed on the side of the actuating rod (38) opposite the anchor (22), characterized in that the actuating rod (38) is loaded against the anchor (22) via the spring element (36), wherein an elastic element (76) is arranged between the contact bridge (44) and the rod head (48).

2. High-voltage contactor (10) or high-voltage relay according to claim 1, characterized in that the elastic element (76) is a spring.

3. High-voltage contactor (10) or high-voltage relay according to claim 2, characterized in that the spring is designed as a spring washer (78).

4. High-voltage contactor (10) or high-voltage relay according to claim 3, characterized in that the spring disc (78) is made of a spring sheet.

5. High-voltage contactor (10) or high-voltage relay according to claim 3 or 4, characterized in that the spring disc (78) has a radially outer bearing surface (80) which is arranged opposite the contact bridge (44), a radially inner bearing surface (88) which is arranged opposite the contact bridge (44) and a central bearing surface (84) arranged radially between the radially outer bearing surface (80) and the radially inner bearing surface (88), which is arranged opposite the rod head (48).

6. High-voltage contactor (10) or high-voltage relay according to claim 5, characterized in that the axial distance of the radially inner support surface (88) to the central support surface (84) is smaller than the distance of the radially outer support surface (80) to the central support surface (84).

7. High-voltage contactor (10) or high-voltage relay according to claim 5 or 6, characterized in that an absolute angle between a radially outer spring section (82), extending from the radially outer bearing surface (80) to the central bearing surface (84) and a parallel to the axis of symmetry of the spring disk (78) is smaller than an absolute angle between a radially inner spring section (86) extending from the radially inner support surface (88) to the central support surface (84), parallel to the axis of symmetry of the spring disc (78).

8. High-voltage contactor (10) or high-voltage relay according to one of the preceding claims, characterized in that the spring element (36) is arranged in the contact chamber (42) and loads the rod head (48) in the direction of the armature (22).

9. High-voltage contactor (10) or high-voltage relay according to one of the preceding claims, characterized in that a clamping disk (50) is arranged axially between the contact bridge (44) and the armature (22) on the actuating rod (38), and a shaped leaf spring (46) is clamped axially between the clamping disk (50) and the contact bridge (44), the outwardly pointing spring arms (55) of which are biased against the contact bridge (44) and the radially inner area of ​​which rests against the clamping disk (50), wherein the contact bridge (44) is loaded by the leaf spring (46) in the direction of the rod head (48).

10. High-voltage contactor (10) or high-voltage relay according to one of the preceding claims, characterized in that the contact chamber (42) is limited by the housing (58) in the direction of the actuator (12) and has a central guide section (64) in which the actuating rod (38) is guided.

11. High-voltage contactor (10) or high-voltage relay according to one of the preceding claims, characterized in that the armature (22) in the first position rests against a core or a return plate (28) of the electromagnetic actuator (12).

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