ELECTRICAL SWITCHING DEVICE WITH LOCKING

Description

[0001] The present invention relates to a switching device according to the preamble of independent claim 1.

[0002] A switching device of this type has at least one fixed contact and a movable contact interacting with it. Furthermore, the switching device of this type comprises an electromagnetic actuating device for driving the movable contact, wherein the electromagnetic actuating device has an excitation coil for generating a magnetic field, a magnetic yoke for amplifying the flux density of the magnetic field, and a magnet armature connected to the movable contact that can be attracted by the magnetic field from an initial position to an attracted position. The electromagnetic actuating device further comprises a locking element that can be moved from a locking position, in which the locking element prevents movement of the magnet armature and / or the movable contact, to an unlocking position, in which the locking element permits movement of the magnet armature and / or the movable contact.The locking element consists at least partially of a ferromagnetic material and is arranged such that it is moved from the unlocking position to the locking position due to the effect of the magnetic field of the drive.

[0003] Typically, conventional electromagnetically actuated switching devices have at least one fixed contact and one movable contact, with the movable contact being moved to the fixed contact by a magnetic armature when the excitation coil of the switching device's electromagnetic actuation device is energized. If the switching device is used in vehicle construction, there is a risk, for example, in the event of an accident, that such large forces may occur that the contacts are inadvertently closed without activating the electromagnetic actuation device. Accidental closing of the contacts must be reliably prevented. This can be achieved, for example, by using a very strong return spring that preloads the magnetic armature into its initial position.The disadvantage of this solution is that the electromagnetic actuator must be sufficiently powerful to overcome the high spring force of the return spring.

[0004] To address this problem, DE 10 2014 211 735 A1 proposes locking the magnet armature in its initial position. A ferromagnetic ball, for example, can be used as the locking element. This ball is accommodated in corresponding recesses of the magnet armature and the magnetic yoke of the excitation coil and, in a locking position, creates a positive connection between the magnet armature and the magnetic yoke. When the excitation coil is energized, the resulting magnetic flux draws the ferromagnetic ball out of the recess of the armature and slightly further into the recess of the magnetic yoke, thus releasing the movement of the magnet armature. DE 10 2014 211 735 A1 thus discloses a switching device according to the preamble of independent claim 1.

[0005] Furthermore, WO 2012 / 033262 A1 discloses a switching device with fixed contacts and interacting movable contacts, wherein the movable contacts are arranged on a movable contact arrangement. The movable contact arrangement is movable by means of an electromagnetic actuating device having a coil and an element for forming a magnetic path. For this purpose, a permanent magnet is arranged on the movable contact arrangement. Furthermore, an armature is provided, which is pivotally connected to the element for forming a magnetic path and engages in a locking part to lock the contacts in the open position. For this purpose, a projection is provided on the armature, which interacts with a stop on the locking part. The armature is preloaded in the locking position by a spring. To close the contacts, the coil is energized. The armature is attracted toward the coil against the force of the spring.This releases the projection of the armature, the movable contact assembly is moved downwards by the force acting from the coil on the permanent magnet and the contacts are closed.

[0006] DE 196 25 657 A1 discloses an electric lifting armature magnet with a magnetic coil arranged on a coil body, with a lifting armature displaceably arranged in the magnetic coil, and with a return spring that loads the lifting armature in the axial direction. In addition, the electric lifting armature magnet comprises a hinged armature to secure the lifting armature against axial displacement. For this purpose, a circumferential groove is provided on the lifting armature, into which the edge of a bore formed in the hinged armature or an arm formed on the hinged armature engages. When current is applied to the magnetic coil, the hinged armature is attracted against the force of a spring, thereby releasing the magnetic armature. The object of the present invention is to further improve the generic switching device. The switching device according to the invention should be particularly simple in design and inexpensive to manufacture, and should ensure reliable unlocking.

[0007] The problem is solved by the features of independent claim 1. Accordingly, the problem is solved according to the invention if the magnetic yoke is designed such that the magnetic yoke has an interruption when the locking element is in the locking position, wherein the interruption in the magnetic yoke is closed by the locking element when the locking element is in the unlocking position, and wherein the magnetic yoke comprises an upper yoke plate and a lower yoke plate which are arranged parallel and spaced from one another and substantially perpendicular to the magnet armature, and between which the excitation coil is arranged, wherein the locking element is arranged on the two yoke plates such that the two yoke plates are completed to form a U-shaped section when the locking element is in the unlocking position.

[0008] According to the invention, the locking element is thus part of the magnetic yoke. The magnetic flux acting on the magnetic armature is amplified when the magnetic yoke is closed. This results in the advantage that the magnetic armature and / or the movable contact can be unlocked reliably and without the risk of jamming the magnetic armature, since no significant forces are initially exerted on the magnetic armature. Only once the magnetic armature and / or the movable contact have been unlocked and the magnetic yoke has been closed by the ferromagnetic locking element is the magnetic flux acting on the magnetic armature amplified, so that the full attractive force is applied. The magnetic yoke is therefore formed by the two yoke plates and the locking element.In the locked position of the locking element, the interruption in the magnetic yoke is formed by an air gap between the locking element and one of the two yoke plates. In the unlocked position of the locking element, the interruption is closed, the locking element rests against both yoke plates, and the magnetic yoke is closed in a U-shape. This results in a simple and lightweight design of the magnetic yoke.

[0009] Advantageous embodiments of the present invention are the subject of the subclaims.

[0010] According to a particularly preferred embodiment of the present invention, it is provided that the electromagnetic actuating device is designed such that the magnet armature is attracted against the force of a return spring of the electromagnetic actuating device when the magnet yoke is closed, whereas the magnetic flux acting on the magnet armature is not sufficient to attract the magnet armature against the force of the return spring when the magnet yoke is interrupted.

[0011] According to another particularly preferred embodiment of the present invention, the locking element is designed in the manner of a hinged anchor. This embodiment offers a particularly simple yet reliable construction.

[0012] According to a further preferred embodiment of the present invention, the locking element is preloaded into the locking position by a return element, preferably in the form of a biasing spring. This securely holds the locking element in the locking position. Thus, the magnet armature is also securely locked, preferably in its initial position. The return element can preferably be implemented in the form of a tension spring or a compression spring.

[0013] According to a further particularly preferred embodiment of the present invention, a direction of movement of the locking element runs transversely to a direction of movement of the magnet armature and preferably encloses an angle of at least 70° to ideally 90° to the direction of movement of the magnet armature. This ensures that a force occurring, for example, in an accident and acting in the direction of movement of the magnet armature has little or no effect on the locking element. If the locking element is designed as a hinged armature, the direction of movement of the locking element is to be understood as the direction of movement of the pivoted end of the locking element - which may change along the path of movement under certain circumstances. This direction can, for example, move along a circular path, provided the hinged armature is rotatably hinged to the magnet yoke.

[0014] According to a further preferred embodiment of the present invention, the magnet armature is designed as a tension rod extending through the excitation coil. This results in a particularly simple and compact design.

[0015] According to another example, the magnetic yoke has a U-shaped section enclosing the excitation coil, wherein the locking element is arranged on the open side of the U-shaped section such that the U-shaped section is completed by the locking element to form a closed yoke when the locking element is in the unlocking position. This embodiment also contributes to a particularly simple design.

[0016] Advantageously, the locking element can furthermore have a projection that interacts with an undercut formed on the magnet armature or the movable contact to lock or release the magnet armature and / or the movable contact. This ensures simple and secure locking or unlocking of the magnet armature or the movable contact.

[0017] It can also be provided that the projection is formed on the magnet armature or on the movable contact and the undercut on the locking element.

[0018] According to a further example, the projection of the locking element is in the form of a protruding nose which cooperates with the undercut in the form of a hook to lock the magnet armature and / or the movable contact, wherein the hook is formed on the magnet armature or the movable contact or is connected to the magnet armature or the movable contact. The hook is preferably designed such that the nose automatically re-engages with the hook when the armature moves from the attracted position to the starting position. The hook is preferably formed on a component rigidly connected to the magnet armature, for example on a contact carrier connected to the magnet armature. However, the hook can also be formed, for example, on the movable contact, which can be connected to the contact carrier not rigidly but via one or more contact pressure springs.In this case, the locking element primarily prevents the movable contact from moving. The magnetic armature is also prevented from moving by the locking element, but only after the contact pressure spring(s) have exhausted their travel. Instead of a protruding nose, the locking element can alternatively have a corresponding recess that engages with the hook.

[0019] Advantageously, it can further be provided that the projection in the locking element is designed in the form of an elongated hole extending substantially perpendicular to the magnet armature, wherein the magnet armature extends through the elongated hole and the magnet armature has an annular groove that forms the undercut and cooperates with the elongated hole in the locking element to lock or unlock the magnet armature. This also ensures simple and secure locking or unlocking of the magnet armature.

[0020] The locking element is preferably designed as a single piece and preferably consists entirely of a ferromagnetic material. However, it can also be designed in multiple parts. For example, the locking element can have a ferromagnetic part, which completes the magnetic yoke in the unlocked position, and a part attached to it that is responsible for the actual locking. In particular, the locking element can have an activation part and a locking part, wherein the locking part and the activation part are connected to one another in an articulated manner.

[0021] Yet another embodiment can provide for the activation part and the locking part to form an angle of 80° to 100° with each other, with the locking part being arranged substantially parallel to the two yoke plates and the elongated hole being formed in the locking part. This also enables a simple and stable design.

[0022] Further preferably, the locking element locks the magnet armature in the initial position when it is in the locking position. In this case, the at least one fixed contact and the at least one movable contact cooperating therewith are preferably open when the magnet armature is in the initial position.

[0023] The switching device is preferably a contactor.

[0024] An embodiment of the present invention is explained in more detail below with reference to drawings.

[0025] They show: Figure 1: a schematic section through a switching device with the magnet armature in the initial position and the locking element in the locking position, Figure 2: the switching device according to Figure 1 with the magnet armature still in the initial position and the locking element in the unlocking position, Figure 3: the switching device from the Figures 1 and 2 after unlocking the magnet armature with the magnet armature in the attracted position, Figure 4: side view of a switching device according to the invention with the magnet armature in the initial position and the locking element in the locking position, and Figure 5: perspective view of the switching device from Figure 4 after unlocking the magnet armature with the magnet armature in the attracted position.

[0026] In the following explanations, identical parts are designated by identical reference numerals. Where a figure contains reference numerals that are not further explained in the corresponding figure description, reference is made to preceding or subsequent figure descriptions.

[0027] The Figure 1 shows a schematic section through a switching device 1. The switching device 1 has two fixed contacts 2 and a movable contact in the form of a contact bridge 3. In the illustration from Figure 1 the electrical contacts are open.

[0028] The switching device 1 further comprises an electromagnetic actuating device for driving the movable contact 3. The electromagnetic actuating device has an excitation coil 4 for generating a magnetic field that acts on a magnet armature 6 designed as a tension rod. The excitation coil 4 is wound on a coil carrier 14. The tension rod 6 is connected at its upper end to a contact carrier 11, which in turn is connected to the contact bridge via corresponding contact pressure springs 13.

[0029] The electromagnetic actuating device further comprises a magnetic yoke for amplifying the magnetic flux acting on the magnetic armature 6. The magnetic yoke has a U-shaped section 5 that surrounds the excitation coil on three sides. The two legs of the U-shaped section 5 cover the two end faces of the hollow cylindrical coil carrier 14. The two legs have corresponding bores 15 through which the magnetic armature 6 extends. At the open end of the U-shaped section, a locking element 7, also ferromagnetic, is hinged to the lower leg of the U-shaped section. The locking element 7 is designed like a hinged armature and is pivotably mounted on the U-shaped section 5 of the magnetic yoke via the joint 8.

[0030] In the Figure 1In the initial position of the magnet armature 6 shown, the locking element 7 is initially in a locking position when the excitation coil is deactivated. For this purpose, the locking element 7 has an outwardly projecting lug 10 at its free end, which is engaged with a hook 12 projecting from the contact carrier 11. A biasing spring 9, which in the illustrated embodiment is designed as a tension spring and is attached to a housing element (not shown), reliably holds the locking element 7 in the locking position when the actuating device is deactivated.

[0031] If the excitation coil 4 is now energized, the locking element 7, designed as a hinged armature, is attracted by the magnetic flux from the U-shaped section 5 of the magnetic yoke, so that the free end of the locking element 7 moves towards the free end of the upper leg of the U-shaped section 5. The hook 12 is thereby released, unlocking the magnetic armature. The locking element 7 is now in an unlocking position. At the same time, the locking element 7 closes the magnetic yoke of the excitation coil ( Figure 2 ), so that the magnetic flux acting on the magnet armature is amplified and the magnet armature is moved from the initial position to the attracted position ( Figure 3 ) so that the electrical contacts are closed.

[0032] Figure 4shows a side view of a further embodiment of a switching device 1 according to the invention in the locking position of the locking element 7. In this position, the contact points of the switching device 1 are open (OFF position). The structure of the switching device 1 according to the second embodiment essentially corresponds to the structure of the Figures 1 to 3 shown switching device. Therefore, only the differences are pointed out below. For elements of the switching device 1 according to the second embodiment that are not described, reference is made to the previous description of the Figures 1 to 3 referred to.

[0033] According to the Fig. 4In the embodiment shown, the magnetic yoke comprises two yoke plates, an upper yoke plate 5.1 and a lower yoke plate 5.2. The two yoke plates 5.1, 5.2 are arranged parallel to one another. Between the two yoke plates 5.1, 5.2, bolts 17 are arranged, running perpendicular to the yoke plates 5.1, 5.2, which hold the yoke plates 5.1, 5.1 at a distance from one another. The bolts 17 are connected to the two yoke plates 5.1, 5.2. The bolts 17 are preferably made of non-magnetic steel or plastic. Tests have shown that bolts made of magnetic materials also produce good results. The two yoke plates 5.1, 5.2 extend essentially perpendicular to the longitudinal axis of the magnet armature 6. The excitation coil 4 is arranged between the two yoke plates 5.1, 5.2.

[0034] The locking element 7 is constructed in two parts and comprises an activation part 7.1 and a locking part 7.2. The activation part 7.1 is preferably made of a ferromagnetic material and is also a component of the magnetic yoke. Furthermore, the activation part 7.1 is designed in the manner of a hinged armature and is pivotally connected to the lower yoke plate 5.2 of the magnetic yoke, i.e., the yoke plate 5.2 facing away from the contact points, via a first joint 8. The locking part 7.2 is pivotally connected to the activation part 7.1 via a second joint 16. The locking part 7.2 is constructed in the manner of a slider. The locking part 7.2 extends approximately at a right angle to the activation part 7.1. Depending on the position of the activation part 7.1, the locking part 7.2 forms an angle of approximately 80° to 100°, preferably approximately 85° to 95°, with the activation part 7.1. The locking part 7.2 extends essentially parallel to the upper yoke plate 5.1 of the magnetic yoke, i.e., the plate facing the contact points. The locking part 7.2 thus extends essentially perpendicular to the direction of movement of the magnetic tank 6.

[0035] The locking part 7.2 can be guided on the upper yoke plate 5.1. Furthermore, the locking part 7.2 has a pin 19 extending in the longitudinal direction of the locking part 7.2. The pin 19 extends from the end face of the locking part 7.2 facing away from the activation part 7.1 in the longitudinal direction of the locking part 7.2 in extension of the locking part 7.2. The upper yoke plate 5.1 has a groove (see Figure 5) which extends essentially perpendicular to the direction of movement of the magnet armature 6 in the upper yoke plate 5.1. The pin 19 of the locking part 7.2 is guided in the groove 20 of the upper yoke plate 5.1. A preload spring 9 is arranged between the pin 19 of the locking part 7.2 and the opposite end of the groove 20 in the upper yoke plate 5.1. One end of the preload spring 9 is plugged onto the pin 19, the other end of the preload spring is fastened to the locking part 7.2. The locking part 7.2 is movable relative to the magnet armature 6 parallel to the yoke plates 5.1, 5.2.

[0036] Furthermore, the locking part 7.2 has an elongated hole 21 that extends in the longitudinal direction of the locking part 7.2. The elongated hole 21 is in Figure 5can be clearly seen. The magnet armature 6 has an armature rod 6.1 which extends from a part of the magnet armature 6 arranged in the excitation coil 4 upwards to the contact carrier 11. The armature rod 6.1 of the magnet armature 6 is essentially cylindrical and passes through the elongated hole 21 of the locking part 7.2. In the area in which the armature rod 6.1 passes through the elongated hole 21 of the locking part 7.2, the armature rod 6.1 has an annular groove 22. In the area of the annular groove 22, the diameter of the armature rod 6.1 is therefore smaller than in the areas of the armature rod 6.1 lying above and below the locking part 7.2. The width of the annular groove 22 in the armature rod 6.1 is slightly greater than the thickness of the locking part 7.2. The width of the elongated hole 21 in the locking part 7.2 is slightly larger than the diameter of the armature rod 6.1 of the magnet armature 6 below the annular groove 21.The magnet armature 6 or the armature rod 6.1 can therefore move upwards and downwards perpendicular to the locking part 7.2 through the elongated hole 21 in the locking part 7.2 when the locking part 7.2 is not in engagement with the annular groove 22 in the armature rod 6.1.

[0037] In Fig. 4 The switching device 1 is shown in the locking position. The activation part 7.1 is pivoted outwards about the joint 8, ie away from the excitation coil 4, so that an air gap 23 is formed between the upper yoke plate 5.1 of the magnetic yoke and the upper end of the activation part 7.1. This air gap 23 forms the interruption of the magnetic yoke in the locking position. The locking part 7.2 is thus pivoted outwards, in Figure 4i.e., to the right, so that one end of the elongated hole 21 in the locking part 7.2 rests against the base of the annular groove 22 in the armature rod 6.1 of the magnet armature 6. The locking part 7.2 thus engages in the annular groove 22 of the armature rod 6.1 of the magnet armature 6 and locks the magnet armature 6 in the axial direction. The magnet armature 6 can therefore not be moved either upwards or downwards, and the contact points of the switching device 1 are locked in the open position. In order to reliably hold the locking element 7, i.e., in particular the locking part 7.2, in the locking position when the actuating device is switched off, the preload spring 9 is provided. As already described, the preload spring 19 is inserted into the groove 20 in the upper yoke plate 5.1 of the magnetic yoke and is fastened to the yoke plate 5.1 and to the locking part 7.2 and presses the locking part 7.2 into the locking position.

[0038] Figure 5 shows the second embodiment of the switching device 1 from Figure 4 After unlocking the magnet armature, the magnet armature is in the attracted position. In this position, the contact points of switching device 1 are closed (ON position).

[0039] To unlock the magnetic armature 6, the excitation coil 4 is energized. As a result, the activation part 7.1 of the locking element 7, designed as a hinged armature, is attracted by the two yoke plates 5.1, 5.2 due to the magnetic flux. The free upper end of the activation part 7.1 is moved towards the free end of the upper yoke plate 5.1 and the air gap 23, and thus also the magnetic yoke, is closed. At the same time, the locking part 7.2 is also displaced essentially perpendicular to the direction of movement of the magnetic armature 6. The end of the elongated hole 21 of the locking part 7.2 is pushed out of the annular groove 22 of the armature rod 6.1 of the magnetic armature 6. The locking part 7.2 is now in an unlocking position. This releases or unlocks the magnetic armature 6. The magnet armature 6 or the armature rod 6.1 can move up and down through the elongated hole 21 in the locking part 7.2.

[0040] As described, the air gap 23 is closed simultaneously. The activation part 7.1 then closes the magnetic yoke of the excitation coil 4. In this second embodiment, the magnetic yoke is formed by the two yoke plates 5.1, 5.2 and the locking element, or in particular the activation part 7.1 of the locking element 7. This increases the magnetic flux acting on the magnet armature 6, and the magnet armature 6 is moved from its initial position to an attracted position against the force of a return spring (not shown). As a result, the contact carrier 11 with the contact bridge 3 arranged thereon is moved toward the fixed contacts 2, and the electrical contacts are closed. List of reference symbols

[0041] 1Switching device 2Fixed contact 3Contact bridge (movable contact) 4Excitation coil 5U-shaped section of the magnetic yoke 5.1Upper yoke plate 5.2Lower yoke plate 6Magnetic armature 6.1Armature rod 7Locking element 7.1Activation part 7.2Locking part 8Joint 9Preload spring 10Nose 11Contact carrier 12Hook 13Contact pressure spring 14Coil carrier 15Bore 16Second joint 17Bolt 19Pin 20Groove 21Elongated hole 22Annular groove 23Air gap

Claims

1. Switching device (1) comprising at least one stationary contact (2) and a movable contact (3) cooperating therewith, and comprising an electromagnetic actuation device for driving the movable contact (3), wherein the electromagnetic actuation device comprises an excitation coil (4) for generating a magnetic field, a magnetic yoke (5.1, 5.2, 7) for amplifying the flux density of the magnetic field, and a magnet armature (6) configured to be pulled by the magnetic field from an starting position to a pulled position and connected to the movable contact (3), wherein the electromagnetic actuation device further comprises a locking element (7) movable from a locking position, in which the locking element (7) prevents movement of the magnet armature (6) and / or the movable contact (3), into an unlocking position, in which the locking element (7) releases a movement of the magnet armature (6) and / or of the movable contact (3), and wherein the locking element (7) consists at least partially of a ferromagnetic material and is configured so as to be transferred from the unlocking position into the locking position due to the action of the magnetic field, characterized in that the magnetic yoke (5.1, 5.2, 7) is configured such that the magnetic yoke has a discontinuity when the locking element (7) is in the locking position, the discontinuity of the magnetic yoke being closed by the locking element (7) when the locking element (7) is in the unlocking position and wherein the magnetic yoke (5) comprises an upper yoke plate (5.1) and a lower yoke plate (5.2) that are arranged parallel to and spaced apart from one another and substantially perpendicular to the magnet armature (6) and between which the excitation coil (4) is arranged, the locking element (7) being arranged on the two yoke plates (5.1, 5.2) such that locking element (7) completes the two yoke plates (5.1, 5.2) to form a U-shaped section when the locking element (7) is in the unlocking position..

2. Switching device (1) according to claim 1, characterized in that the electromagnetic actuation device is configured to amplify the magnetic flux acting on the magnet armature (6) when the discontinuity of the magnetic yoke (5.1, 5.2, 7) is closed by the locking element (7).

3. Switching device (1) according to claim 2, characterized in that the electromagnetic actuation device is configured to pull the magnet armature (6) against the force of a return spring of the electromagnetic actuation device when the magnetic yoke (5.1, 5. 2, 7) is closed, whereas the magnetic flux acting on the magnet armature (6) is insufficient to pull the magnet armature (6) against the force of the return spring when the magnetic yoke is interrupted.

4. Switching device (1) according to any one of claims 1 to 3, characterized in that the locking element (7) is configured in the manner of a swivel armature.

5. Switching device (1) according to any one of claims 1 to 4, characterized in that the locking element (7) is biased into the locking position by a resetting element, preferably in the form of a pretensioning spring (9).

6. Switching device (1) according to any one of claims 1 to 5, characterized in that a direction of movement of the locking element (7) extends transversely to a direction of movement of the magnet armature (6) and preferably forms an angle of 70° to 90° with the direction of movement of the magnet armature (6).

7. Switching device (1) according to any one of claims 1 to 6, characterized in that the locking element (7) has a projection that cooperates with a back taper formed on the magnet armature (6) or on the movable contact to lock or release the magnet armature (6) and / or the movable contact.

8. Switching device (1) according to claim 7, characterized in that the projection in the locking element (7) is configured in the form of an elongated hole (21) extending essentially perpendicular to the magnet armature (6), the magnet armature (6) extending through the elongated hole (21) and the magnet armature (6) having an annular groove (22) that forms the back taper and cooperates with the elongated hole (21) in the locking element (7) for locking or unlocking the magnet armature (6).

9. Switching device (1) according to any one of claims 1 to 8, characterized in that the locking element (7) is formed in several parts and has an activating part (7.1) and a locking part (7.2), the locking part (7.1) and the activating part (7.2) being hingedly connected to one another.

10. Switching device (1) according to claim 9, characterized in that the activating part (7.1) and the locking part (7.2) form an angle of 80° to 100° with one another, the locking part (7.2) being arranged essentially parallel to the two yoke plates (5.1, 5.2) and the elongated hole (21) being formed in the locking part (7.2).

11. Switching device (1) according to any one of claims 1 to 10, characterized in that the locking element (7) in its locking position locks the magnet armature (6) in the starting position.

12. Switching device (1) according to claim 11, characterized in that the at least one stationary contact (2) and the at least one movable contact (3) cooperating therewith are open when the magnet armature (6) is in the starting position.