EP3616224A1

EP3616224A1 - Relay

Info

Publication number: EP3616224A1
Application number: EP18719562.3A
Authority: EP
Inventors: Peter Bobert
Original assignee: TDK Electronics AG
Current assignee: TDK Electronics AG
Priority date: 2017-04-28
Filing date: 2018-04-23
Publication date: 2020-03-04
Also published as: JP6877579B2; US20200251292A1; US11004621B2; JP2020518112A; DE102017109210B4; DE102017109210A1; CN110770866B; CN110770866A; WO2018197430A1

Abstract

The invention relates to a relay (1) which has a first contact (2), a second contact (3), and a movable element (4), which can be arranged in a closed position and in an open position, wherein, in the closed position, the movable element (4) connects the first contact (2) electrically to the second contact (3), wherein the first contact (2) and the second contact (3) are isolated electrically from each other when the movable element (4) is arranged in the open position, and wherein the relay (1) has at least one bimetallic strip (13) which is configured so as to deform in the event of a temperature increase and which is arranged in such a way that, after the bimetallic strip is deformed, the at least one bimetallic strip (13) forces the movable element (4) against the first and the second contact (2, 3).

Description

Description Relay The present invention relates to a relay. A relay is an electromagnetically operated switch operated by electric current with at least two switch positions.

Is the relay in a closed position?

Switch position, an electrical circuit is closed between fixed contacts and a movable element and it can flow a current. At the contact points between the fixed contacts and the movable element of the contact resistance is increased compared to the remaining lines. Accordingly, it comes at the contact points to high losses and as a result, heat loss and a considerable heat can form. In particular, when using a relay in a closed housing or at high ambient temperatures may be such

Heat loss disturbing effect, since under certain circumstances, a complex cooling may be required.

Object of the present invention is therefore, a

specify improved relay, in which, for example, the generation of heat loss can be limited. In particular, the emergence of heat loss should be avoided or at least reduced without having to use a cooling system. This object is achieved by a relay according to claim 1.

A relay is proposed which has a first contact, a second contact and a movable element. The movable element can be in a closed

Position and in an open position. In the closed position, the movable member electrically connects the first contact to the second contact. The first contact and the second contact are electrically isolated from each other when the movable element in the open

Position is arranged. The relay has at least one bimetallic strip, which is designed to deform at a temperature increase and the like

is arranged that the bimetal strip after his

Deformation presses the movable member against the first and the second contact. In this case, the bimetal strip can particularly preferably press the movable element against the first and second contact without deforming the movable element in the process. In other words, only the bimetallic strip deforms, not the movable element.

Will the movable element through the at least one

Bimetallic strip pressed against the first and the second contact, thereby the contact pressure between the movable member and the contacts can be increased. An increased contact pressure has a reduction of

Contact resistance between the contacts and the

result in a mobile element. Accordingly, you can

lower losses occur when the movable member is pressed by the at least one bimetallic strip against the contacts. Lower losses can lead to crossovers between the contacts and the

less heat is generated in the moving element and thus excessive heating of the relay can be avoided.

Otherwise, prolonged excessive heating could cause the surfaces of the contacts to burn off the relay would be damaged and the life of the relay would be limited. The use of at least one

Bimetallic strip and thus enabling increased contact force can thus extend the life of the relay

improve.

A bimetal strip may have two layers of different metals, which are connected to one another in a material-locking or form-fitting manner. Bimetallic strips are designed to change shape as the temperature changes. Cause for the change of shape

different thermal expansion coefficients of

used metals.

The bimetallic strip may have a rest state, which may also be referred to as a non-deformed state. The bimetallic strip may be in its quiescent state when the temperature of the bimetallic strip is below its activation temperature. The bimetal strip may also have an active state, which may also be referred to as a deformed state. The bimetallic strip may be in the active state when the temperature of the bimetallic strip is above its activation temperature. In the active state, the bimetallic strip due to the

Temperature increase to be deformed. The activation temperature may be higher than a normal room temperature of 21 ° C. The activation temperature of the bimetallic strip can

for example, between 45 ° C and 55 ° C. The at least one bimetal strip is configured to deform after a temperature increase. The deformation can occur when the temperature of the

Bimetal strip the above activation temperature exceeds. The temperature increase can be caused by heat loss, which generates a current flowing through the relay at the contact points of the movable element with the contacts.

The movable element may be relative to the contacts

be mobile. The movable element may be a bridge. The movable element may be mechanically connected to an armature which can be moved by a magnet.

The relay may have a magnet to do so

is configured to move the movable member from the open position to the closed position when the magnet is turned on. The magnet may be further configured to move the movable member from the

closed position to move to the open position when the magnet is turned off.

The magnet may be an electromagnet. The magnet may be a lifting magnet. If the magnet is turned on, it can exert a force on the movable element, due to the

moving element is moved to the closed position. The magnet can exert a force on an armature which is mechanically connected, for example via a spring-loaded connection, to the movable element. If the magnet is switched off, the movable element of the

closed position to be moved to the open position.

The magnet may be designed to be movable

Element in its closed position as long as the magnet is on. After deformation of the at least one bimetallic strip in consequence of the

Increasing the temperature, the bimetal strip can exert an additional force on the movable element, which also contributes to the movable element in the closed

Hold position and ensures that the contact force with which the movable element is pressed against the contacts, is increased.

A first end of the at least one bimetallic strip may be attached to the movable member. Accordingly, the bimetal strip can apply a force directly to the

exercise movable element.

The movable member may have an upper surface facing the first and second contacts and a lower surface facing the upper side. On the

Top may be arranged a contact element which is adapted to, in the closed position of the

movable member to be electrically contacted directly with the first contact, wherein the first end of the at least one bimetallic strip is arranged on the underside of the movable element below the contact element. For example, a surface normal, perpendicular to the top and to the bottom of the movable

Elements stands, cutting both the contact element and the first contact. If the first end of the at least one bimetallic strip is arranged in the immediate vicinity of the contact element, the heat loss arising between the contact element and the first contact rapidly reaches the at least one bimetallic strip and thus leads to an increase in the temperature of the at least one bimetallic strip. The closer the bimetallic strip at the contact point of the first Contact is attached to the contact element, the more

he can react more sensitively to the resulting heat loss.

A second end of the at least one bimetallic strip may be free-standing. Accordingly, the second end can not be fixedly attached to another element. Upon deformation of the bimetallic strip, the position of the second end may change relative to the first end. The relay can have a mechanical stop. The at least one bimetallic strip may be arranged such that when the movable element is arranged in the closed position and after the deformation of the movable element

Bimetal strip as a result of the temperature increase, the second end of the at least one bimetallic strip rests against the stop. A concern with the stop may in this case mean that the bimetal strip is clamped between the stop and the movable element. It can the

Bimetallic strip exert a force on the movable member, by which the contact force between the movable member and the contacts is increased.

The mechanical stop may be arranged on an armature which is spring-loaded with the movable element

Connection is connected. The armature may be configured to be moved by the magnet. In this case, the armature and thus the mechanical stop can be moved by a greater distance than the movable element. A contact force with which the movable element in the closed position against the first and the second

Contact can be determined by a spring constant of the spring-loaded connection when moving Element is in the closed position and the at least one bimetallic strip is not due to a

Temperature increase is deformed. The contact force can be determined by a contact pressure of the at least one bimetallic strip, when the movable element is in the closed position and the at least one

Bimetallic strip is deformed as a result of a temperature increase. In this case, the contact force, which is determined by the contact pressure of the at least one bimetallic strip, be greater than the contact force, the spring constant

is determined. Accordingly, a contact resistance between the contacts and the movable member may be reduced due to the higher contact force when the at least one bimetallic strip has deformed. A reduced contact resistance leads to lower losses and thus less heating due to heat loss.

The at least one bimetal strip may be arranged to increase, after deformation, a contact force with which the movable member is pressed in the closed position against the first and second contacts.

Accordingly, after the deformation of the

Bimetallic strip, the contact force between the movable element and the contacts be increased, so that the

Heat losses are reduced and excessive heating of the relay can be avoided.

The at least one bimetallic strip may have a layer comprising MnCul8NilO and a layer comprising FeNi36 or consist of these two layers. The layer comprising MnCul8NilO can be an active

Form component of the bimetallic strip. The relay can have two bimetallic strips. In this case, a first bimetal strip in the immediate vicinity of the first contact and a second bimetallic strip may be arranged in the immediate vicinity of the second contact. All in the

Connection with the at least one bimetallic strip

disclosed features may also apply to both bimetallic strips. In a further alternative embodiment, the relay may comprise more than two bimetal strips, each of which may be attached to the movable element.

In the following, the present invention is based on the

Figures explained in more detail.

FIG. 1 shows a relay in an open position.

Figure 2 shows the relay in a closed position with the bimetallic strips in an idle state.

Figure 3 shows the relay in its closed position with the bimetallic strips in an activated state.

FIG. 1 shows a relay 1 in an open position.

If the relay 1 is in its open position, no current can flow through the relay 1.

The relay 1 has a first contact 2 and a second contact 3. Furthermore, the relay 1 has a movable element 4, which may be in an open position or in a closed position. Figure 1 shows the movable element 4 in the open position. In the open position, the movable element 4 does not electrically connect the first contact 2 with the second contact 3. In the open position of the relay 1, this is located movable element 4 in its open position. In the closed position of the relay 1 is the

movable element 4 in its closed position. The movable element 4 has an upper side 5, which faces the first contact 2 and the second contact 3. On the upper side 5 of the movable element 4, a first contact element 6 and a second contact element 7 are arranged. When the movable member 4 is in its open position, the first contact 2 and the first one are

Contact element 6 of the movable element 4 separated by a gap 8 from each other. Furthermore, the second contact 3 and the second contact element 7 are also separated from each other by a gap 8. Accordingly, the first contact 2 and the second contact 3 are electrically isolated from each other.

The relay 1 further comprises an armature 9 and a magnet 10 which is adapted to move the armature 9. The magnet 10 is an electromagnet that can be turned on and off. The magnet 10 is a lifting magnet.

The armature 9 can assume a first position and a second position. Figure 1 shows the armature 9 in its first

Position. Is the anchor 9 in its first

Position, the relay 1 is in the open position.

If the armature 9, as shown in Figure 2, in the second position, the relay 1 is in the closed position

Position .

The armature 9 comprises a metallic material. If the magnet 10 is turned on, the field generated by the magnet 10 exerts a force on the armature 9, the armature 9 from the In the first position shown in Figure 1 in the second position shown in Figure 2 moves.

The armature 9 is mechanically connected to the movable element 4 via a spring-loaded connection 11, which has a mechanical spring. If the armature 9 due to a

When the magnet 10 is moved to its second position, the movable element 4 also moves. The spring-loaded connection 11 is compressed and thus absorbs part of the movement of the armature 9, so that the movable element 4 moves by a smaller distance than the armature 9. When the magnet 10 is turned on, the armature 9 and the movable element 4 move into one

Direction to the first and the second contact 2, 3 to.

On an underside 12 of the movable element 4, which is opposite to the upper side 5, two bimetallic strips 13, 13 a are arranged. Each of the two bimetal strips 13, 13 a has a layer comprising a first material and a layer comprising a second material, wherein the

Layers are connected together. The first and the second material differ in theirs

Thermal expansion coefficient. For example, the first material may be MnCul8MilO and the second material may be FeNi36. If the bimetallic strips 13, 13a are subjected to a temperature change, they deform as a result of the different ones

Thermal expansion coefficients of the two layers. Each of the two bimetal strips 13, 13a can be in a rest state and an active state. By a

Temperature change, the bimetallic strip 13, 13 a transferred from its idle state to the active state. At a usual room temperature of 21 ° C are the

Bimetallic strip 13, 13a in their respective resting state. If the temperature rises and exceeds one

Activation temperature, the bimetallic strips 13, 13a deform and thereby assume their active state. If the temperature decreases and falls below the activation temperature, the bimetallic strips 13, 13a return to their idle state. The active state of the bimetallic strip 13, 13a

differs from the idle state in that the

Bimetallic strip 13, 13a are deformed. In particular, the extent of the bimetallic strip 13, 13a in a direction perpendicular to the bottom 12 of the movable element 4 in the active state is greater than in the idle state.

A first end 14, 14a of each of the two bimetal strips 13, 13a is fixed to the underside 12 of the movable element 4. In this case, the first end 14 of the first

Bimetallstreifens 13 below the first contact element 6, which is arranged on the upper side 5 of the movable member 4, attached. The first end 14a of the second

Bimetal strip 13a is disposed immediately below the second contact element 7. Accordingly, when the contact elements 6, 7 are heated, the resulting heat may well reach the bimetallic strips 13, 13a and heat the bimetal strips 13, 13a.

A second end 15, 15a of the two bimetal strips 13 is free-standing. The second end 15, 15a of the two

Accordingly, bimetallic strip 13, 13a is not fixed and can move relative to the first end 14, 14a. In particular, the second end 15, 15a of the two

Bimetallic strip 13, 13 a is not fixed to the movable element 4. Furthermore, the second end 15, 15 a of the two Bimetallic strip 13, 13a as shown in Figure 1 recognizable from

be spaced apart from the movable element 4 and thus be further away from the movable element 4 than the first end 14, 14 a.

The relay 1 has a mechanical stop 16. The mechanical stop 16 is formed by a sleeve which is fixed to the armature 9. In the open state of the relay 1, the second end 15, 15 a of the two

Bimetallic strip 13, 13a each of the mechanical

Stop 16 separated by a gap.

Figure 2 shows the relay 1 in its closed position, wherein the bimetallic strip 13, 13a are each in their undeformed states of rest. In the closed position of the relay 1, a current can flow through the relay 1. When the magnet 10 is turned on, it moves the armature 9 and thus the movable element 4 toward the contacts 2, 3. The movable element 4 is transferred to its closed position. In the closed position, the first and the second contact 2, 3 on the on the

movable element 4 arranged contact elements 6, 7 electrically connected to each other. Accordingly, a current can flow through the relay 1. Immediately after the

Closing the relay 1, this is not yet heated.

Accordingly, the bimetal strips 13, 13a undergo no deformation and initially remain in their quiescent states.

If the relay 1 is now closed and a current flows through the first contact 2 and the movable element 4 to the second contact 3, so arise at the point of contact between the first contact 2 and the first contact element. 6

or between the second contact 3 and the second contact element 7 losses resulting from the

limited contact force between the contacts 2, 3 and the contact elements 6, 7 result. These losses cause heat, which leads to heating of the relay 1.

In particular, the contacts 2, 3, the contact elements 6, 7 and their respective immediate environment are strongly heated. Accordingly, the first ends 14, 14a of the bimetallic strip 13, 13a and thus the entire

Bimetallic strip 13, 13 a heated.

The contact force between the movable element 4 and the contacts 2, 3 is determined essentially by the spring constant of the sprung connection 11 when the movable element 4 is in its closed position and the bimetal strips 13, 13a, as shown in FIG their respective resting state.

Figure 3 shows the relay 1 in its closed state, wherein the bimetallic strips 13, 13a have deformed. If the bimetal strips 13, 13a have been heated beyond the activation temperature, deformation of the bimetallic strips 13, 13a occurs. In the deformation of

Bimetallic strip 13, 13 a, the second end 15, 15 a of the respective bimetallic strip 13, 13 a from the bottom 12 of the movable member 4 moves away. The second end 15, 15a of the bimetallic strip 13, 13a strikes against the mechanical stop 16 of the relay 1, which prevents further deformation of the bimetallic strip 13, 13a. As a result, the bimetallic strip 13, 13 a is pressed between the mechanical stop 16 and the movable element 4. The bimetal strips 13, 13a now exert a force on the movable element 4, which presses the movable element 4 in the direction of the first and the second contact 2, 3. By this force exerted by the bimetallic strip 13, 13a, the contact force on the contacts 2, 3 is increased. As shown in Fig. 3, the bimetallic strips 13, 13a push the movable member 4 against the first and second contacts 2, 3 without deforming the movable member 4 thereby. Thus, despite the deformation of the bimetallic strips 13, 13a, the movable element 4 is not deformed as shown.

By increasing the contact force is for a better connection between the contacts 2, 3 and the

Contact elements 6, 7 taken care, so that the losses can be reduced. Accordingly arises at the transitions between the first contact 2 to the first contact element 6 and between the second contact 3 to the second

Contact element 7 now less heat. The bimetallic strips 13, 13a thus make it possible to increase the contact pressure between the movable element 4 and the contacts 2, 3 at a too high heating of the contacts 2, 3 and in this way to reduce the losses at the crossing points and thereby excessive heating to restrict.

Now, if the relay 1 is turned off by the magnet 10 is turned off, first the anchor 9 in his

moved back open position. In this case, the movable element 4 is moved to its open position.

Now no current flows between the contacts 2, 3 and the movable element 4. Accordingly, no further heat is generated due to losses. There is therefore a cooling of the bimetallic strip 13, 13a, so that they are deformed back into their resting state after a short time.

This again results in the one shown in FIG

Configuration of relay 1. Reference sign list

1 relay

2 first contact

3 second contact

4 movable element

5 top

6 first contact element

7 second contact element

8 gap

9 anchors

10 magnet

11 spring-loaded connection

12 bottom

13, 13a bimetallic strip

14, 14a first end

15, 15a second end

16 stop

Claims

Relay (1),

comprising a first contact (2), a second one

Contact (3) and a movable element (4), which can be arranged in a closed position and in an open position,

the movable element (4) electrically connecting the first contact (2) to the second contact (3) in the closed position,

wherein the first contact (2) and the second contact (3) are electrically isolated from each other when the

movable element (4) is arranged in the open position, and

wherein the relay (1) comprises at least one bimetallic strip (13) which is adapted to engage in a

Temperature increase to deform and the like

arranged that the at least one bimetallic strip (13) after its deformation, the movable element (4) against the first and the second contact (2, 3) presses.

Relay (1) according to claim 1,

the relay (1) having a magnet (10) adapted to move the movable member (4) from the open position to the closed position when the magnet (10) is turned on.

Relay (1) according to one of the preceding claims, wherein a first end (14) of the at least one

Bimetal strip (13) is attached to the movable element (4). Relay (1) according to the previous claim,

wherein the movable element (4) has an upper side (5) which faces the first and the second contact (2, 3) and a lower side (12) which is the upper side (5)

opposite,

wherein on the upper side (5) a contact element (6) is arranged which is configured to be in direct contact with the first contact (2) in the closed position of the movable element (4),

wherein the first end of the at least one

Bimetallic strip (13) on the bottom of the

movable element (4) below the contact element (6) is arranged.

Relay (1) according to one of the preceding claims,

wherein a second end (15) of the at least one

Bimetal strip (13) is free-standing.

Relay (1) according to the previous claim,

wherein the relay (1) has a mechanical stop (16), and

wherein the at least one bimetallic strip (13) is arranged such that when the movable element (4) is arranged in the closed position and after deformation of the at least one bimetallic strip (13) as a result of the temperature increase, the second end of the at least one bimetallic strip (13 ) abuts against the stop (16). Relay (1) according to the previous claim,

wherein the mechanical stop (16) is arranged on an armature (9) which is connected to the movable element (4) via a spring-loaded connection (11).

Relay (1) according to the previous claim,

wherein a contact force with which the movable element (4) is pressed in the closed position against the first and the second contact (2, 3) is determined by a spring constant of the sprung connection (11) when the movable element (4) is in the closed position and the at least one bimetallic strip (13) not in consequence of

Temperature increase is deformed,

and

wherein the contact force of a contact pressure of the at least one bimetallic strip (13) is determined when the movable member (4) in the

is closed position and the at least one bimetallic strip (13) is deformed as a result of a temperature increase.

Relay (1) according to one of the preceding claims, wherein the at least one bimetal strip (13) is arranged such that it after the deformation of a

Increases contact force with which the movable member (4) in the closed position against the first and the second contact (2, 3) is pressed.

Relay (1) according to one of the preceding claims, wherein the at least one bimetallic strip (13) has a layer comprising MnCul8NilO and a layer

having FeNi36. Relay (1) according to one of the preceding claims, wherein the relay (1) comprises two bimetal strips (13, 13a).