WO2020007743A1

WO2020007743A1 - Relay comprising shock-compensated contact bridge

Info

Publication number: WO2020007743A1
Application number: PCT/EP2019/067391
Authority: WO
Inventors: Rainer Schmelz
Original assignee: Gruner Ag
Priority date: 2018-07-04
Filing date: 2019-06-28
Publication date: 2020-01-09
Also published as: EP3591684A1

Abstract

The invention relates to a relay (1) for closing or interrupting the electric circuit between two relay contacts (2₁, 2₂), comprising: an electroconductive contact bridge (5) that can be moved between two relay positions in the relay housing (4) and which rests on the two relay contacts (2₁, 2₂) in the one, closed relay position and is lifted off the two relay contacts (2₁, 2₂) in the other, open relay position, a magnet drive (7) comprising a magnet coil (8) and an armature (9) which is movably guided parallel or approximately parallel to the direction of movement (6) of the contact bridge (5) and can be moved by pole changing of the magnet coil (8), and a double-armed lever (12) mounted in the relay housing (4) such that it can be rotated about a shaft (13) extending at a right angle to the direction of movement (6), the contact bridge (5) being coupled to one lever arm (12a) of the lever and the armature (9) being coupled to the other lever arm (12b) of the lever.

Description

Relay with shock-compensated contact bridge

The present invention relates to a relay for closing or interrupting the circuit between two relay contacts.

Such relays are well known and are used, for example, as disconnectors in the vehicle sector for 48V applications or in a battery management system for Li-ion batteries. In situations in which the battery cells can no longer be balanced, such as in critical thermal states of the battery or in dangerous situations (crash), the relay disconnects the vehicle electrical system (+ pole) from vehicle consumers. This protects the cells and the vehicle from critical situations. The requirements in a vehicle make it necessary to withstand extreme shock situations, for example in the event of a crash: the relay has opened and must remain in this state even after the crash; Here acceleration values of approx. 150 g occur for 10 ms. In decentralized battery storage systems such as solar energy stores up to 50VDC, these relays are also integrated as disconnectors in battery management systems. The relay must also be able to switch off overcurrent situations, ie avoid short circuits in the battery.

It is therefore the object of the present invention to ensure, in the case of a relay, that the relay, once opened, is not fired again by a crash.

This object is achieved according to the invention by a relay for closing or interrupting the circuit between two relay contacts, comprising:

an electrically conductive contact bridge that can be moved between two relay positions, which is in contact with the two relay contacts in one, closed relay position and is lifted off the two relay contacts in the other, open relay position,

a magnet drive with a magnet coil and an armature displaceably guided parallel or almost parallel to the direction of displacement of the contact bridge, which armature can be displaced by reversing the polarity of the magnet coil, and

one in the relay housing rotatable about an axis running perpendicular to the direction of displacement, double-armed lever, on one lever arm the contact bridge and on the other lever arm the armature.

According to the invention, the signs of acceleration acting on the armature and on the contact bridge are reversed in the event of a shock, so that the total torque acting on the armature and on the contact bridge is mutually reduced by the lever deflection and the relay therefore remains in its previous state despite the shock. The relay can be designed in a monostable version as normal open or in a bistable version. For the mass M1 and the lever length L1 of the contact bridge and for the mass M2 and the lever length L2 of the armature, the following preferably applies: 0.5 <(M1 * L1) / (M2 * L2) <2, particularly preferably: 0.95 <(M1 * L1) / (M2 * L2) <1.05. The more the torques acting on the armature and on the contact bridge are compensated for, the smaller the resulting total torque, and the relay remains in its previous state despite the shock. Ideally, the torques acting on the armature and the contact bridge in the event of an impact are completely compensated, ie the following applies: M1 * L1 = M2 * L2. If additional parts are attached to the contact bridge, via which the contract bridge is articulated on one lever arm, then the mass M1 is defined by the total mass of all moving parts on the contact bridge side and the lever arm L1 by the articulation point on the double-armed lever.

For a compact design of the relay, it is advantageous if the contact bridge and the armature are arranged on the same side of the double-armed lever. Alternatively, the contact bridge and the armature can also be arranged on different sides of the double-armed lever.

The contact bridge is preferably resiliently mounted in the displacement direction in a bridge cage which is displaceably guided in the relay housing in the displacement direction and on which a lever arm is articulated. With this spring suspension bridge suspension, the mass M1 is given by the total mass of the contact bridge and bridge cage. The contact bridge is advantageously biased in the bridge cage in the direction of the relay contacts, which on the one hand specifies the contact pressure with which the contact bridge is in contact with the relay contacts in the closed relay position, and on the other hand causes the relay to close with less bounce.

The contact bridge can be formed by a single wide bridge or, which is preferred, by a plurality of parallel, narrow individual bridges, each with two contact heads.

The two electrical relay contacts are preferably arranged on the free ends of two mutually facing, U-shaped relay connection contacts. This reduces the dynamic lifting of the contact bridge at high short-circuit currents, since the magnetic field, which is generated by the current flowing through the U-shaped relay connection contacts, also pushes the contact bridge in the contact closing direction.

Further advantages and advantageous configurations of the subject matter of the invention can be found in the description, the drawing and the claims. Likewise, the features mentioned above and those listed further can be used individually or in combination in any combination. The embodiment shown and described is not to be understood as an exhaustive list, but rather has an exemplary character for the description of the invention.

Show it:

1 shows the relay according to the invention with a displaceable contact bridge and with a magnetic drive;

FIGS. 2a-2c a Hebeium deflection between the magnetic drive and the contact bridge in a side view (Fig. 2a), in a perspective view (Fig. 2b) and in a view from below (Fig. 2c); and

FIGS. 3a, 3b a spring-loaded mounting of the contact bridge in a bridge cage in a perspective view obliquely from above (FIG. 3a) and in a perspective view from below (FIG. 3b).

The in fig. 1 and 2 shown relay (disconnector) 1 is used to close or interrupt the circuit between two electrical relay contacts 2i, 2 ₂ , which are arranged as contact heads on the free ends of two mutually facing, U-shaped relay connection contacts 3i, 3 ₂ . As shown in Fig. 2b, each relay contact 2-i, 2z is formed by a series of three contact heads.

In the space between the two U-shaped relay connection contacts 3i, 3 ₂ , an electrically conductive contact bridge 5 (for example made of copper) is guided in the direction of the double arrow 6 between two relay positions in the relay housing 4. In the one, closed relay position, the contact bridge 5 is in each case with three contact buttons 5-i or 5 ₂ on the two relay contacts 2-j, 2 ₂ and is in the other, opened rice position, which is shown in FIGS. 1 and 2 is shown, of the two relay contacts 2 _1; 2 ₂ lifted off.

To move the contact bridge 5, the relay 1 has a magnetic drive 7 with a magnet coil 8 and a parallel to the direction of displacement 6 of the contact bridge 5 displaceably guided armature 9, which poles the solenoid 8 against the restoring force of a compression spring 10 in its one end position other end position is displaceable. In the relay housing 4, a double-armed lever 12 is also rotatably mounted about an axis 13 extending at right angles to the direction of displacement 6, on one lever arm 12a of which the armature 9 at 14a and on the other arm 12b of which the contact bridge 5 at 14b are articulated in the exemplary embodiment shown are the magnetic drive 7 as a monostable solenoid and the armature 9 as a plunger (plunger) guided linearly in the magnet coil 8.

As in fig. 3a, 3b, the contact bridge 5 can be resiliently mounted in a bridge cage 15 (for example made of steel) which carries the axis 14b and is in turn guided in the relay housing 4 in the direction of displacement 6 between the two two relay positions. The contact bridge 5 consists of several (here three examples) parallel single bridges 5a, 5b, 5c, each with two contact heads 5 · i, 5 ₂ , which are guided independently of one another in the back cage 15 in the direction of displacement 6. In Fig. 3a, the left single bridge 5a is omitted for reasons of clarity.

The individual bridges 5a, 5b, 5c are each prestressed by a compression spring 17 supported on the cage ceiling 16 in contact with an intermediate floor 18 of the bridge cage 15. The intermediate floor 18 is designed as a separate steel sheet and has a plurality of bent guide fingers 19 in order to separate the individual bridges 5a, 5b, 5b from one another and to guide them against tilting in the direction of displacement 6. The bridge cage 15 carries a guide cap 20 which overlaps the cage cover 16 and by means of which the bridge cage 15 is displaceably guided in a plastic holder 21 of the relay housing 4. For minimal contact with the plastic holder 21- sen the guided side winch of the bridge cage 15 each only a selective guide projection 22 and the guided sides of the guide cap 20 a plurality of guide ribs 23, so that in operation, despite hot individual bridges 5a, 5b, 5b, the bridge cage 15 and the guide cap 20 preferably not with the plastic holder 21 in Come into contact and can melt on it or if possible the individual bridges 5a, 5b, 5b cannot move or block against each other.

To switch relay 1, the magnetic field of magnet coil 8 is switched on or off. The anchor 9 is, as in FIGS. 1 and 2, when the magnetic field is switched off, pressed down by the compression spring 10 and, as a result, the bridge cage 15, together with the individual bridges 5a, 5b, 5b, is also pressed up via the lever 10 until the individual bridges 5a, 5b, 5b of in the open relay position the relay contacts 2i, 2 _{2 are} lifted off. When the magnetic field is switched on, the armature 9 is drawn upward into the magnet coil 8 against the action of the compression spring 10 and, as a result, the bridge cage 15 together with individual bridges 5a, 5b, 5c is also pulled down via the lever 10 until the individual bridges 5a, 5b, 5b on the relay contacts 2i, 2 ₂ . The contact pressure of the contact buttons 5i, 5z on the two relay contacts 2i, 2 ₂ is given by the compressive force of the compressed compression spring 17. In the closed relay position, the compression springs 17 also counteract the deflection of the individual bridges 5a, 5b, 5b in the opening direction of the relay 1 , which leads to reduced bounce closing of relay 1.

The mutually facing, U-shaped relay connection contacts 3i, 3 ₂ also reduces dynamic lifting at high short-circuit currents, since the magnetic field generated by the current flowing through the U-shaped relay connection contacts 3i, 3 ₂ , the individual bridges 5a, 5b , 5b additionally presses in the contact closing direction.

In order to keep the relay 1 in the desired state even in the event of an impact, the moving parts of the magnet drive 7, i.e. the magnet armature 9, and the contact bridge 5 (including the bridge cage 15) are designed such that for the mass M1 (including a bridge cage 15) and the lever length 11 of the contact bridge 5 and for the mass M2 and the lever length L2 of the armature 9 applies: M1 * L1 ~ M2 * L2. In this In the event of an impact, the torques acting on the armature 9 and on the contact bridge 5 cancel each other out, which is achieved by the lever deflection. The signs of acceleration and torque are therefore inverse.

Claims

SP12626PCT Rk / sh 28.06.2019 claims

1. Relay (1) for closing or interrupting the circuit between two relay contacts (2i, 2 ₂ ), having

an electrically conductive contact bridge (5) which can be moved between two relay positions in the relay housing (4) and which is in one closed relay position against the two relay contacts (2i, 2 ₂ ) and in the other, open relay position of the two relay contacts ( 2 · i, 2 ₂ ) is lifted off,

a magnet drive (7) with a magnet coil (8) and an armature (9) which is displaceably guided parallel or almost parallel to the direction of displacement (6) of the contact bridge (5) and which can be displaced by reversing the polarity of the magnet coil (8), and

a double-armed lever (12) mounted in the relay housing (4) rotatable about an axis (13) extending at right angles to the direction of displacement (6), on one lever arm (12a) the contact bridge (5) and on the other lever arm (12b) the armature (9) are articulated.

2. Relay according to claim 1, characterized in that for the mass M1 and the lever length L1 of the contact bridge (5) and the mass M2 and the lever length L2 of the armature (9) applies: 0.5 <(M1 * L1) / ( M2 ^* L2) <2.

3. Relay according to claim 2, characterized in that for the mass M1 and the lever length L1 of the contact bridge (5) and the mass M2 and the lever length L2 of the armature (9) applies: 0.95 <(M1 * L1) / ( M2 * L2) <1.05, in particular the following applies: M1 * L1 = M2 * L2.

4. Relay according to one of the preceding claims, characterized in that the contact bridge (5) and the armature (9) are arranged on the same side of the double-armed lever (12).

5. Relay according to one of the preceding claims, characterized in that the relay contacts (2 ₁ 2 ₂ ) are each formed by at least one contact button, in particular by a number of several contact heads.

6. Relay according to one of the preceding claims, characterized in that the contact bridge (5) is guided in a bridge cage (15) which is displaceably guided in the relay housing (4) in the direction of displacement (6) and on the one lever arm (12b) is articulated, is spring-mounted in the direction of displacement (6).

7. Relay according to claim 6, characterized in that the contact bridge (5) in the bridge cage (15) in the direction of the relay contacts (2i, 2 ₂ ) is biased.

8. Relay according to one of the preceding claims, characterized in that the contact bridge (5) is formed by at least two parallel individual bridges (5a, 5b, 5c), each with two contact heads (5i, 5 ₂ ).

9. Relay according to one of the preceding claims, characterized in that the two electrical relay contacts (2i, 2 ₂ ) are arranged at the free ends of two mutually facing, U-shaped relay connection contacts (3i, 3 ₂ ).