CN220341135U - Movable contact spring, contact unit and relay - Google Patents

Abstract

The utility model provides a movable reed, a contact unit and a relay, and relates to the technical field of electric power. The movable reed is used for contacting with or separating from a pair of stationary contact leading-out ends; the movable reed is arranged on one side of the movable reed towards the leading-out end of the fixed contact, the top surface of the movable reed is provided with a first arc isolation groove, and the first arc isolation groove is used for preventing an arc from moving towards the direction of approaching the leading-out ends of the fixed contact. The movable reed is provided with the first arc isolation groove towards one side of the fixed contact leading-out end, namely the first arc isolation groove is arranged on the top surface of the movable reed to prevent the electric arc from moving, thereby isolating and cutting off the transfer path of the electric arc, preventing the electric arc from being transferred to the central line of the length direction of the movable reed, avoiding the occurrence of arc short circuit generated by two groups of movable and static contacts between the movable reed and a pair of fixed contact leading-out ends, enabling the electric arc to be efficiently extinguished on the originally set magnetic field arc extinguishing path, and improving the arc extinguishing capability.

Description

Movable contact spring, contact unit and relay

Technical Field

The utility model relates to the technical field of electric power, in particular to a movable reed, a contact unit and a relay.

Background

A relay is an electronic control device applied to an automatic control circuit, and the relay is provided with a control system (also called an input loop) and a controlled system (also called an output loop), and is actually an 'automatic switch' for controlling larger current by smaller current. Therefore, the circuit plays roles of automatic adjustment, safety protection, circuit switching and the like. The existing high-voltage direct-current relay adopts a movable reed direct-acting structure as one of the relays, namely, the two fixed contacts are matched with one movable reed to realize the functions of switching on and switching off loads.

The principle of breaking load of the high-voltage direct current relay is that a permanent magnet is arranged to generate a directional magnetic blowing magnetic field, when the moving contact and the fixed contact are separated to generate an electric arc, the electric arc is rapidly elongated under the action of the magnetic blowing magnetic field until the electric arc is broken, and the breaking of the load is realized. The most severe breaking is called limit breaking, the load of limit breaking is several times of rated load, if the electric arc is not stable enough at the moving contact and the moving contact, the electric arc is transferred on the surface of the moving contact, the electric arc can not be extinguished mainly along a magnetic arc-pulling path, and finally the electric arc can not be broken, and the product can be burnt out by explosion due to overload overheat.

In addition, in order to meet the short-circuit resistance requirement, the existing high-voltage direct-current relay is generally provided with a soft magnet, namely a short-circuit resistance ring, near the internal dynamic and static contacts so as to generate electromagnetic attraction force for resisting electric repulsive force when short-circuit current passes. However, the soft magnetic body is magnetized in the vicinity of the current-carrying conductor, and thus has an attractive effect on the arc.

Because of the arrangement of the soft magnet, namely the anti-short circuit ring, when the relay is in limit breaking, the electric arc is not only influenced by the magnetic blowing field, but also influenced by the magnetized soft magnet, so that the electric arc is disordered, and the limit breaking capacity of the high-voltage direct current relay is reduced. Meanwhile, the short circuit ring is burnt out, the short circuit resistance effect is affected, and if an auxiliary contact is arranged above the short circuit ring, the auxiliary contact is burnt out by an electric arc.

Disclosure of Invention

The movable reed, the contact unit and the relay provided by the utility model have the advantages that the reliability of arc breaking is improved, and the safety is good.

According to a first aspect of the present utility model, there is provided a movable contact spring for contacting or separating from a pair of stationary contact terminals;

the movable reed is arranged on one side of the movable reed, which faces the leading-out end of the fixed contact, and is arranged on the top surface of the movable reed, and the first arc isolation groove is used for preventing an electric arc from moving towards the direction of approaching the pair of leading-out ends of the fixed contact.

In some embodiments, the first arc isolation groove comprises a first groove wall and a first groove bottom which are connected with each other, and the extending direction of the first groove wall and the length direction of the movable reed form an included angle;

the arc moves to the connection part between the first groove wall and the top surface of the movable contact spring to form an arc-gathering, and the height difference between the top surface of the movable contact spring facing to one side of the fixed contact leading-out end and the bottom of the first groove is used for preventing the arc from moving towards the direction of approaching to the fixed contact leading-out ends.

In some embodiments, the contact part of the movable reed and the pair of stationary contact leading ends is a first contact part, and the first arc isolation groove is arranged between the inner edges of the first contact part.

In some embodiments, the first arc isolation groove is a through groove along the width direction of the movable reed.

In some embodiments, the number of the first arc isolation grooves is one, and the parts of the movable reed, which are positioned at two sides of the first arc isolation groove along the length direction of the movable reed, are respectively and correspondingly abutted against a pair of stationary contact leading-out ends; the distance between the two side edges of the first arc isolation groove along the length direction of the movable reed is smaller than or equal to the distance between the inner edges of the first contact part.

In some embodiments, the number of the first arc-isolating grooves is two, the two first arc-isolating grooves are arranged corresponding to the pair of stationary contact leading-out ends, and the distance between the outer edges of the two first arc-isolating grooves along the length direction of the movable reed is smaller than or equal to the distance between the inner edges of the first contact part.

In some embodiments, the first arc isolating slot is at least one of a linear structure, a convex structure and an X-shaped structure.

In some embodiments, the first arc isolation groove is of an arc structure, and the first arc isolation groove is annularly arranged around the leading-out end of the stationary contact.

In some embodiments, the side wall of the movable contact spring is provided with an arc-isolating structure for preventing the arc from moving toward the direction in which the pair of stationary contact terminals approach each other.

In some embodiments, the contact part of the movable reed and the pair of stationary contact leading ends is a first contact part, and the arc isolation structure is arranged between the inner edges of the first contact part.

In some embodiments, the arc isolation structure is a second arc isolation groove arranged on the side wall of the movable reed; and/or the number of the groups of groups,

The arc isolation structure is an arc isolation protrusion arranged on the side wall of the movable reed.

In some embodiments, the second arc-isolating slot includes a second slot wall and a second slot bottom that are connected to each other;

the electric arc moves to the connection position between the second groove wall and the movable reed side wall to form an arc aggregation, and the height difference between the movable reed side wall and the second groove bottom is used for preventing the electric arc from moving towards the direction that the pair of fixed contact leading-out ends are close to each other.

In some embodiments, the second arc separation groove is a through groove along the axial direction of the stationary contact leading-out end.

In some embodiments, the number of the arc isolation structures is plural, and the plurality of the arc isolation structures are arranged at two sides of the movable reed along the length direction of the movable reed; and/or the number of the groups of groups,

the number of the arc isolation structures is multiple, and the arc isolation structures are arranged on two sides of the movable reed along the width direction of the movable reed.

According to a second aspect of the present utility model, a contact unit according to an embodiment of the present utility model includes a pair of stationary contact terminals and the movable contact spring described above for contacting or separating from the pair of stationary contact terminals.

In some embodiments, the anti-short circuit assembly is at least arranged on one side of the movable reed facing the fixed contact leading-out end, and generates suction force when the movable reed breaks down and generates high current so as to resist electric repulsive force between the movable reed and the fixed contact leading-out end.

According to a third aspect of the present utility model, a relay according to an embodiment of the present utility model includes the above-described contact unit.

One embodiment of the present utility model has the following advantages or benefits:

according to the movable reed, the contact unit and the relay, the movable reed is contacted with or separated from the pair of stationary contact leading-out ends, when the movable reed is contacted with the stationary contacts at the bottoms of the pair of stationary contact leading-out ends, current flows in from one stationary contact leading-out end, and flows out from the other stationary contact leading-out end after passing through the movable reed, so that a communication load is realized. The movable reed is provided with the first arc isolation groove towards one side of the fixed contact leading-out end, namely the first arc isolation groove is arranged on the top surface of the movable reed, and the arc is prevented from moving along the top surface of the movable reed, so that the arc is isolated and cut off on the top surface transfer path of the movable reed, the arc is prevented from being transferred to the central line of the length direction of the movable reed, the arc short circuit generated by two groups of movable and static contacts between the movable reed and a pair of fixed contact leading-out ends is avoided, the arc can be efficiently extinguished on the original set magnetic blowing magnetic field arc extinguishing path, and the arc extinguishing capability is improved.

Drawings

For a better understanding of the utility model, reference may be made to the embodiments illustrated in the following drawings. The components in the drawings are not necessarily to scale and related elements may be omitted in order to emphasize and clearly illustrate the technical features of the present utility model. In addition, the relevant elements or components may have different arrangements as known in the art. Furthermore, in the drawings, like reference numerals designate identical or similar parts throughout the several views. The above and other features and advantages of the present utility model will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings.

Wherein:

fig. 1 is a schematic diagram showing the cooperation of a movable contact and a stationary contact leading-out terminal according to a first embodiment of the present utility model;

fig. 2 is a schematic diagram showing an explosion structure of a movable contact and a stationary contact lead-out terminal according to a first embodiment of the present utility model;

fig. 3 is a schematic structural view of a movable contact spring and a stationary contact lead-out terminal according to a first embodiment of the present utility model;

FIG. 4 shows a cross-sectional view of FIG. 3 at A-A;

fig. 5 is a schematic structural view of a movable spring according to a first embodiment of the present utility model;

fig. 6 is a schematic structural diagram of a relay according to a first embodiment of the present utility model;

Fig. 7 shows a second schematic structural diagram of the relay according to the first embodiment of the present utility model;

FIG. 8 shows a cross-sectional view of FIG. 7 at B-B;

fig. 9 is an exploded view of a relay according to a first embodiment of the present utility model;

fig. 10 shows a first schematic diagram of the cooperation of the movable reed and the fixed contact lead-out terminal provided in the second embodiment of the present utility model;

fig. 11 shows a schematic diagram of an explosion structure of a movable contact and a stationary contact lead-out terminal according to a second embodiment of the present utility model;

fig. 12 is a schematic diagram showing a first structure of a movable contact and a stationary contact lead-out terminal according to a second embodiment of the present utility model;

FIG. 13 shows a cross-sectional view I of FIG. 12 at C-C;

fig. 14 shows a second schematic diagram of the cooperation of the movable contact spring and the fixed contact lead-out terminal provided in the second embodiment of the present utility model;

fig. 15 shows a schematic diagram of an explosion structure of a movable contact and a stationary contact lead-out terminal according to a second embodiment of the present utility model;

fig. 16 shows a second schematic structural view of a movable contact spring and a stationary contact lead-out terminal according to a second embodiment of the present utility model;

FIG. 17 shows a second cross-sectional view of FIG. 16 at D-D;

fig. 18 shows a third schematic diagram of the cooperation of the movable contact spring and the fixed contact lead-out terminal provided in the second embodiment of the present utility model;

Fig. 19 shows an exploded view of a movable contact and a stationary contact according to a third embodiment of the present utility model;

fig. 20 shows a third schematic structural diagram of the movable contact spring and the stationary contact lead-out terminal according to the second embodiment of the present utility model;

FIG. 21 shows a third cross-sectional view of FIG. 20 at E-E;

fig. 22 is a schematic diagram showing the matching of the movable contact spring and the fixed contact lead-out terminal according to the third embodiment of the present utility model;

fig. 23 is a schematic diagram showing an explosion structure of a movable contact and a stationary contact terminal according to a third embodiment of the present utility model;

fig. 24 is a schematic view showing the structures of a movable contact and a stationary contact leading-out terminal according to a third embodiment of the present utility model;

FIG. 25 shows a cross-sectional view of FIG. 24 at F-F;

fig. 26 is a schematic diagram showing the matching of the movable contact spring and the fixed contact lead-out terminal according to the fourth embodiment of the present utility model;

FIG. 27 shows a cross-sectional view of FIG. 26 at G-G;

fig. 28 is a schematic diagram showing an explosion structure of a movable contact and a stationary contact terminal according to a fourth embodiment of the present utility model;

fig. 29 is a cross-sectional view showing a movable contact and a stationary contact terminal provided in a fourth embodiment of the present utility model;

fig. 30 is a schematic structural view of a movable contact spring according to a fourth embodiment of the present utility model;

FIG. 31 shows a cross-sectional view of FIG. 30 at I-I;

fig. 32 shows a second schematic structural diagram of a movable contact spring according to a fourth embodiment of the present utility model;

FIG. 33 shows a cross-sectional view of FIG. 32 at J-J;

fig. 34 is a schematic diagram showing the cooperation of the movable contact spring and the stationary contact lead-out terminal provided in the fifth embodiment of the present utility model;

fig. 35 is a schematic diagram showing an explosion structure of a movable contact and a stationary contact terminal according to a fifth embodiment of the present utility model;

fig. 36 is a schematic view showing the structures of a movable contact and a stationary contact leading-out terminal provided in the fifth embodiment of the present utility model;

FIG. 37 shows a cross-sectional view of FIG. 36 at K-K;

fig. 38 is a schematic diagram showing the cooperation of the movable contact spring and the stationary contact terminal provided in the sixth embodiment of the present utility model;

fig. 39 is a schematic diagram showing an explosion structure of a movable contact and a stationary contact terminal provided in a sixth embodiment of the present utility model;

fig. 40 is a schematic structural view of a movable contact spring and a stationary contact lead-out terminal according to a sixth embodiment of the present utility model;

FIG. 41 shows a cross-sectional view of FIG. 40 at L-L;

wherein reference numerals are as follows:

1. a contact vessel; 2. a contact assembly; 3. an anti-short circuit component; 4. a pushing assembly; 5. an arc extinguishing unit;

11. An insulating cover; 12. a frame piece;

21. a stationary contact lead-out end;

22. a movable reed; 220. a first contact portion; 221. a thrust section; 2211. a through hole;

222. a first arc isolation groove; 223. a second arc isolation groove; 224. arc isolation bulges;

31. an upper magnetizer; 32. a lower magnetizer;

41. a push rod unit; 411. a push rod; 412. a fixing piece; 412. a limit protrusion; 413. a base;

42. a U-shaped bracket; 421. a limiting hole;

43. an elastic member;

44. an electromagnet unit; 441. a coil former; 442. a coil; 443. a movable iron core; 444. a stationary core; 445. a U-shaped yoke; 446. a magnetic conduction cylinder; 447. a spring;

51. an arc extinguishing magnet; 52. and (5) a yoke iron clip.

Detailed Description

The technical solutions in the exemplary embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the exemplary embodiments of the present utility model. The example embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the present utility model, and it should be understood that various modifications and changes can be made to the example embodiments without departing from the scope of the utility model.

In the description of the present utility model, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance unless explicitly specified or limited otherwise; the term "plurality" refers to two or more than two; the term "and/or" includes any and all combinations of one or more of the associated listed items. In particular, references to "the/the" object or "an" object are likewise intended to mean one of a possible plurality of such objects.

Unless specified or indicated otherwise, the terms "connected," "fixed," and the like are to be construed broadly and are, for example, capable of being fixedly connected, detachably connected, or integrally connected, electrically connected, or signally connected; "coupled" may be directly coupled or indirectly coupled through intermediaries. The specific meaning of the above terms in the present utility model can be understood by those skilled in the art according to the specific circumstances.

Further, in the description of the present utility model, it should be understood that the terms "upper", "lower", "inner", "outer", and the like in the exemplary embodiments of the present utility model are described in terms of the drawings, and should not be construed as limiting the exemplary embodiments of the present utility model. It will also be understood that in the context of an element or feature being connected to another element(s) "upper," "lower," or "inner," "outer," it can be directly connected to the other element(s) "upper," "lower," or "inner," "outer," or indirectly connected to the other element(s) "upper," "lower," or "inner," "outer" via intervening elements.

Example embodiments will now be described more fully with reference to the accompanying drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus detailed descriptions thereof will be omitted.

Example 1

As shown in fig. 1 to 4, the present embodiment provides a movable contact spring 22, which is suitable for the relay technical field, and the movable contact spring 22 is used for contacting with or separating from a pair of stationary contact terminals 21.

The movable reed 22 provided in this embodiment is in contact with or separated from the pair of stationary contact terminals 21, and when the movable reed 22 is in contact with the stationary contacts at the bottoms of the pair of stationary contact terminals 21, current is allowed to flow in from one stationary contact terminal 21, and after passing through the movable reed 22, current flows out from the other stationary contact terminal 21, thereby realizing load communication.

When the movable reed 22 is separated from the fixed contacts at the bottoms of the pair of fixed contact leading-out ends 21, the electric arc is automatically disconnected along with the separation of the movable reed 22 and the fixed contacts between the fixed contact leading-out ends 21 and the magnetic blow-out arc if the electric arc is elongated to a certain extent; if the electric arc is not stable enough at the moving contact point, the electric arc is transferred on the surface of the moving reed 22 or the static contact point leading-out end 21, the electric arc can not be extinguished mainly along the magnetic blow-out arc path, and finally the electric arc can not be broken, and even the relay is burnt out by explosion.

To solve this problem, as shown in fig. 1 to 4, the movable contact 22 provided in the present embodiment has a top surface of the movable contact 22 on a side facing the stationary contact leading-out ends 21, and the top surface of the movable contact 22 is provided with a first arc-isolating groove 222, and the first arc-isolating groove 222 is used for preventing the arc from moving toward the direction in which the pair of stationary contact leading-out ends 21 approach each other.

The movable reed 22 provided in this embodiment, the first arc isolation groove 222 is disposed on the top surface of the movable reed 22, and blocks the electric arc from moving along the top surface of the movable reed 22, so as to isolate and cut off the transfer path of the electric arc on the top surface of the movable reed 22, and block the electric arc from transferring to the center line of the length direction of the movable reed 22, so as to avoid the occurrence of arc short circuit generated by two sets of movable contacts between the movable reed 22 and the pair of stationary contact leading-out ends 21, and enable the electric arc to be efficiently extinguished on the originally set magnetic field extinction path, thereby improving the extinction capability.

In one embodiment, as shown in fig. 1-5, the first arc isolating groove 222 includes a first groove wall and a first groove bottom that are connected to each other, and an extending direction of the first groove wall forms an included angle with a length direction of the movable reed 22. Wherein the arc moves to a junction between the first groove wall and the top surface of the movable contact spring 22 to form an arc-gathering, and a height difference between the top surface of the movable contact spring 22 and the first groove bottom serves to hinder the movement of the arc toward the direction in which the pair of stationary contact terminals 21 approach each other.

When the extending direction of the first groove wall is set at an angle to the longitudinal direction of the movable contact spring 22, the extending direction of the first groove wall is different from the longitudinal direction of the movable contact spring 22, so that the moving path of the arc along the longitudinal direction of the movable contact spring 22 and toward the direction in which the pair of stationary contact lead-out ends 21 approach each other can be cut off to a certain extent. Because the first arc isolation groove 222 has the first groove wall and the first groove bottom which are connected with each other, the connection part between the first groove wall and the top surface of the movable reed 22 is an edge, the arc moves to the edge to form an arc gathering, meanwhile, the height difference between the top surface of the movable reed 22 and the first groove bottom is a drop on the arc transfer path, the drop makes the arc not easy to move towards the central line of the length direction of the movable reed 22, and the arc extinguishing effect is improved by utilizing the combination of the edge and the drop.

In one embodiment, the contact portion of the movable contact spring 22 with the pair of stationary contact terminals 21 is a first contact portion 220, and the first arc separating groove 222 is disposed between inner edges of the first contact portion 220.

In other words, the first contact portion 220 is specifically two sets of moving contacts, and because the moving reed 22 and the pair of stationary contact terminals 21 contact each other to generate an arc, the first arc isolation groove 222 is disposed between the inner edges of the first contact portion 220 to cut off the path of the arc transferred to the inner side direction of the stationary contact terminals 21, so as to avoid the arc short circuit generated by the two sets of moving contacts between the moving reed 22 and the pair of stationary contact terminals 21, and ensure the high efficiency and the thoroughness of arc extinction.

The inner side specifically means a side where the pair of stationary contact terminals 21 are close to each other (Q is a direction where the pair of stationary contact terminals 21 are close to each other as shown in fig. 1), or a side close to a center line in a longitudinal direction of the movable reed 22 (L is a longitudinal direction of the movable reed 22 as shown in fig. 1, and T is a width direction of the movable reed 22). Accordingly, the first arc separating groove 222 is provided on the side of the first contact portion 220 facing the inside, or alternatively, the first arc separating groove 222 is provided between the center lines of the two stationary contact terminals 21 (M is the center line of the stationary contact terminal 21 as shown in fig. 1).

In one embodiment, as shown in fig. 1-5, the first arc isolating slot 222 is a through slot along the width of the movable reed 22.

If the first arc-separating groove 222 extends in the length direction of the movable reed 22, the arc can be transferred along a portion of the top surface of the movable reed 22 where the first arc-separating groove 222 is not provided, with a risk of arc shorting. For this reason, the first arc-separating groove 222 is provided as a through groove extending in the width direction of the movable contact 22, and since the through groove is provided so as to extend through the width direction of the movable contact 22, after the arc enters the first arc-separating groove 222, the transfer path of the arc toward the direction in which the pair of stationary contact terminals 21 approach each other is completely cut off.

In one embodiment, the number of the first arc-isolating grooves 222 is two, the two first arc-isolating grooves 222 are disposed corresponding to the pair of stationary contact terminals 21, and the distance between the outer edges of the two first arc-isolating grooves 222 along the length direction of the movable contact 22 is less than or equal to the distance between the inner edges of the first contact portion 220.

In other words, the first arc isolating grooves 222 are disposed on one side of the pair of stationary contact leading-out ends 21, or the two first arc isolating grooves 222 are disposed corresponding to the two stationary contact leading-out ends 21 and disposed on the inner side of the first contact portion 220, so that the arc generated by separating the two sets of moving contacts is isolated correspondingly by the two first arc isolating grooves 222, and the arc isolating effect is further improved.

In one embodiment, as shown in fig. 1-5, the first arc-isolating slot 222 has an arc-shaped structure, and the first arc-isolating slot 222 is disposed around the stationary contact leading-out end 21.

Since the bottom of the stationary contact terminal 21 is similar to a cylindrical structure, the shape of the first arc-isolating groove 222 is adapted to the shape of the bottom of the stationary contact terminal 21, and the arc-isolating groove 222 of the arc structure is disposed along the shape of the stationary contact terminal 21 and around the stationary contact terminal 21, thereby impeding the transfer path of the arc in all directions.

It will be appreciated that the first arc-isolating grooves 222 of the arc structure extend from one side to the other side of the movable contact 22 in the width direction, and then contact portions are formed at both ends of the movable contact 22 in the length direction of the movable contact 22 and at portions where the first arc-isolating grooves 222 are not provided, the contact portions being for contact with the stationary contact terminal 21.

The present embodiment also provides a contact unit including a contact assembly 2, the contact assembly 2 including a pair of stationary contact terminals 21 and the movable contact 22 described above, the movable contact 22 being adapted to contact or separate from the pair of stationary contact terminals 21.

The movable contact spring 22 provided in this embodiment is used for contacting with or separating from a pair of stationary contact terminals 21, and when the movable contact spring 22 contacts with the stationary contacts at the bottoms of the pair of stationary contact terminals 21, current is enabled to flow in from one stationary contact terminal 21, and current flows out from the other stationary contact terminal 21 after passing through the movable contact spring 22, so that load communication is achieved.

In one embodiment, as shown in fig. 6-9, the contact unit includes an insulating cover 11, both of which are connected by a frame piece 12, the insulating cover 11 and the yoke plate defining a contact chamber. The contact chamber provides an insulating environment for contact between the movable spring 22 and the stationary contact lead-out 21.

The embodiment also provides a relay, which comprises the contact unit.

In the relay provided in this embodiment, the movable reed 22 of the contact unit is in contact with or separated from the pair of stationary contact terminals 21, and when the movable reed 22 is in contact with the stationary contacts at the bottoms of the pair of stationary contact terminals 21, current is enabled to flow in from one stationary contact terminal 21, and current flows out from the other stationary contact terminal 21 after passing through the movable reed 22, so that load communication is achieved.

In one embodiment, as shown in fig. 8-9, the relay further includes a push assembly 4, the push assembly 4 including a push rod unit 41, an elastic member 43, and a U-shaped bracket 42. Wherein the push rod unit 41 includes a base 413 and a push rod 411, and upper portions of the base 413 and the push rod 411 may be integrally injection-molded. The U-shaped bracket 42 and the base 413 enclose a frame structure, the movable spring 22 and the elastic piece 43 are arranged in the frame structure enclosed by the U-shaped bracket 42 and the base 413, one end of the elastic piece 43 is abutted against the base 413, the other end is abutted against the movable spring 22, and the elastic piece 43 can provide elastic force, so that the movable spring 22 has a trend of being far away from the base 413 and approaching the stationary contact leading-out end 21.

Specifically, the push rod unit 41 and the U-shaped bracket 42 are engaged with each other through the stopper protrusion 412 and the stopper hole 421, and the movement force of the push rod unit 41 can be transmitted to the U-shaped bracket 42 for driving the movable contact spring 22 to move, so that the movable contact spring 22 is conveniently used to contact or separate from the pair of stationary contact lead-out terminals 21.

As shown in fig. 8-9, the push assembly 4 of the relay further includes an electromagnet unit 44, the electromagnet unit 44 being disposed on a side of the yoke plate facing away from the insulating cover 11. The push rod unit 41 is in driving connection with the electromagnet unit 44, and the push rod unit 41 is movably arranged in a driving cavity enclosed by the metal cover and the yoke plate and is abutted against the movable reed 22 through a via hole of the yoke plate. When the electromagnet unit 44 is energized, the push rod unit 41 can be driven to move, and the movable reed 22 is driven to move so as to contact with or separate from the stationary contact leading-out end 21.

The electromagnet unit 44 includes a bobbin 441, a coil 442, a stationary core 444, a movable core 443, a U-shaped yoke 445, a magnetic cylinder 446, and a spring 447. The bobbin 441 is disposed in the U-shaped yoke 445, and the bobbin 441 has a hollow cylindrical shape and is formed of an insulating material. The magnetic conductive tube 446 is inserted into the bobbin 441, and the coil 442 surrounds the bobbin 441. The stationary core 444 has a first through hole provided corresponding to the through hole of the yoke plate for the push rod unit 41 to pass therethrough. The movable iron core 443 is movably disposed in the magnetic cylinder 446 and disposed opposite to the stationary iron core 444, and the springs 447 are disposed between the stationary iron core 444 and the movable iron core 443 and can be respectively abutted thereto, and the movable iron core 443 is connected to the push rod unit 41 for being attracted by the stationary iron core 444 when the coil 442 is energized. The plunger 443 and the pushrod unit 41 may be screw-coupled, riveted, welded, or otherwise connected.

The working process of the relay provided by the embodiment is as follows:

when the coil 442 is energized, the stationary iron core 444 attracts the movable iron core 443, the movable iron core 443 drives the push rod unit 41 to move upward, the spring 447 between the stationary iron core 444 and the movable iron core 443 is compressed, and the push rod unit 41 pushes the movable reed 22 to move through the U-shaped bracket 42 and the elastic member 43, so that two ends of the movable reed 22 are respectively contacted with the two stationary contact leading-out ends 21, and the process of closing the movable contact is completed.

When the coil 442 is disconnected from the current, the stationary iron core 444 releases the attraction to the movable iron core 443, and under the elastic force of the compressed spring 447, the movable iron core 443 drives the push rod unit 41 to move downward, so that the movable contacts at both ends of the movable reed 22 are separated from the two stationary contact lead-out terminals 21, thereby completing the process of moving and stationary contact separation.

In one embodiment, as shown in fig. 8-9, the relay further comprises an arc extinguishing unit 5, the arc extinguishing unit 5 being disposed in the hollow chamber of the housing for extinguishing an arc of the contact assembly 2. The arc extinguishing unit 5 includes two arc extinguishing magnets 51. The quenching magnets 51 may be permanent magnets, and each quenching magnet 51 may be substantially rectangular parallelepiped. The two arc extinguishing magnets 51 are provided on both sides of the insulating cover 11, respectively, and are disposed opposite to each other along the longitudinal direction of the movable reed 22.

In the present embodiment, two arc extinguishing magnets 51 are respectively located on the left and right sides of the insulating cover 11. The polarities of the faces of the two quenching magnets 51 facing each other are opposite. That is, the left side of the arc extinguishing magnet 51 located on the left side of the insulating cover 11 is an S-pole and the right side is an N-pole, and the left side of the arc extinguishing magnet 51 located on the right side of the insulating cover 11 is an S-pole and the right side is an N-pole.

Of course, the polarities of the surfaces of the two arc extinguishing magnets 51 facing each other may be designed to be identical, for example, the left surface of the arc extinguishing magnet 51 located on the left side of the insulating cover 11 is an S-pole and the right surface is an N-pole, and the left surface of the arc extinguishing magnet 51 located on the right side of the insulating cover 11 is an N-pole and the right surface is an S-pole.

Thus, by providing two opposing arc extinguishing magnets 51, a magnetic field can be formed around the contact assembly 2. Therefore, the arc generated between the stationary contact terminal 21 and the movable contact 22 is elongated in a direction away from each other by the magnetic field, and arc extinction is achieved.

As shown in fig. 8 to 9, the arc extinguishing unit 5 further includes two yoke clips 52, and the two yoke clips 52 are provided corresponding to the positions of the two arc extinguishing magnets 51. And, two yoke clips 52 surround the insulating cover 11 and the two arc extinguishing magnets 51. Through the design that yoke iron clamp 52 encircles arc extinguishing magnet 51, can avoid the magnetic field that arc extinguishing magnet 51 produced to outwards spread, influence the arc extinguishing effect. The yoke iron clips 52 are made of a soft magnetic material. Soft magnetic materials may include, but are not limited to, iron, cobalt, nickel, alloys thereof, and the like.

Example two

The present embodiment is similar to the embodiment, and differs only in the structure of the first arc separating groove 222.

The first arc isolation groove 222 provided in this embodiment is at least one of a linear structure, a convex structure and an X-shaped structure.

Specifically, as shown in fig. 10-13, the first arc isolation groove 222 has a linear structure, so that the first arc isolation groove 222 has a groove structure, the structure is simple, the production and the processing are convenient, and the overall structural strength of the movable reed 22 is relatively high because the groove width of the first arc isolation groove 222 along the length direction of the movable reed 22 is relatively narrow.

As shown in fig. 14 to 17, the first arc isolation groove 222 has a convex structure, so that the first arc isolation groove 222 has a fold line groove structure, and the bending degree of the arc transmission path is increased, thereby improving the arc extinguishing effect.

As shown in fig. 18-21, the first arc isolation groove 222 has an X-shaped structure, and the X-shaped structure includes two slots disposed in a crossing manner, so that the electric arcs on a single side can be isolated from a transmission path through the two slots, and the dual arc isolation effect is achieved, and the isolation and arc extinguishing effects are good.

It is to be understood that the shapes of the two first arc separation grooves 222 in this embodiment may be the same or different, for example: one of the first arc isolating grooves 222 is of a convex structure, and the other first arc isolating groove 222 is of a linear structure.

It is to be understood that the first arc isolation groove 222 provided in this embodiment includes, but is not limited to, a linear structure, a convex structure, an X-shaped structure, an S-shaped structure, a conical structure, etc., and the specific shape thereof may be adjusted according to actual production conditions.

Example III

This embodiment is similar to the embodiment, and differs only in the number and structure of the first arc separating grooves 222.

As shown in fig. 22-25, the number of the first arc-isolating grooves 222 provided in the present embodiment is one, and the portions of the movable reed 22 located at two sides of the first arc-isolating groove 222 along the length direction of the movable reed 22 are respectively abutted against a pair of stationary contact leading-out ends 21 correspondingly.

Because a first arc isolating slot 222 is arranged between a pair of stationary contact leading-out ends 21, the slot width of the first arc isolating slot 222 along the length direction of the movable reed 22 is relatively wide, the part of the movable reed 22, which is not provided with the first arc isolating slot 222, is respectively provided with two contact parts at the two ends of the movable reed 22 along the length direction of the movable reed 22, the two contact parts are correspondingly abutted against the pair of stationary contact leading-out ends 21, the arc isolating process of two groups of movable and stationary contacts can be realized by utilizing the first arc isolating slot 222, the structure is simple, and the production cost is relatively low.

In one embodiment, as shown in fig. 22-25, the distance between the two edges of the first arc isolating slot 222 along the length direction of the movable contact 22 is less than or equal to the distance between the inner edges of the first contact portion 220.

Specifically, the first arc-isolating slot 222 extends along the slot width of the movable reed 22 in the length direction to near the inner edge of the bottom of the fixed contact lead-out end 21 or is flush with the inner edge of the bottom of the fixed contact lead-out end 21, so that the edge between the first slot wall of the first arc-isolating slot 222 and the top surface of the movable reed 22 is as close to the bottom of the fixed contact lead-out end 21 as possible, the arc can be concentrated on the edge as soon as possible, and the risk of the arc transferring to the center line direction of the movable reed 22 is reduced by utilizing the drop between the top surface of the movable reed 22 and the first slot bottom of the first arc-isolating slot 222.

Example IV

This embodiment is similar to the first embodiment, except that the movable spring 22 is added to the first or second embodiment.

As shown in fig. 26 to 29, the movable contact 22 according to the present embodiment is provided with an arc-shielding structure provided on a side wall of the movable contact 22 for shielding movement of an arc toward a direction in which the pair of stationary contact terminals 21 approach each other.

The movable reed 22 provided in this embodiment sets up the arc isolation structure in movable reed 22 lateral wall, blocks that the electric arc shifts to movable reed 22 length direction's central line to the isolated and transfer route of cutting off electric arc at movable reed 22 lateral wall avoids appearing the electric arc short circuit that two sets of movable contacts between movable reed 22 and a pair of stationary contact leading-out terminal 21 produced, makes the electric arc can high-efficient arc extinction on the magnetic field arc extinction route of original settlement, has improved the extinction ability.

In one embodiment, the arc isolation structure is disposed between the inner edges of the two first contact portions 220.

In other words, the arc isolation structure is arranged at the inner side of the mutual contact part of the fixed contact leading-out end 21 and the movable contact spring 22 so as to cut off the path of the arc transferring to the inner side direction of the fixed contact leading-out end 21, and avoid the arc short circuit generated by two groups of movable contacts between the movable contact spring 22 and the pair of fixed contact leading-out ends 21 so as to ensure the high efficiency and the thoroughness of arc extinction.

In one embodiment, the number of the arc isolation structures is plural, and the plurality of the arc isolation structures are arranged at two sides of the movable reed 22 along the length direction of the movable reed 22; and/or the number of the arc isolating structures is plural, and the plurality of the arc isolating structures are arranged at two sides of the movable reed 22 along the width direction of the movable reed 22.

Specifically, the number of the arc isolating structures is four, each side of the movable reed 22 along the length direction of the movable reed is provided with two arc isolating structures, each side of the movable reed 22 along the width direction of the movable reed is provided with two arc isolating structures, and the four arc isolating structures are arranged at four corners of the thrust part 221 of the movable reed 22, so that the electric arc can be isolated by the arc isolating structures no matter the electric arc is transferred along any direction along the side wall of the movable reed 22, and the arc isolating effect is further improved.

In one embodiment, as shown in fig. 26-29, the arc isolation structure is a second arc isolation groove 223 disposed on the side wall of the movable contact 22; the second arc-isolating groove 223 includes a second groove wall and a second groove bottom connected to each other; wherein the arc moves to the junction between the second groove wall and the side wall of the movable contact spring 22 to form an arc-gathering, and the difference in height between the side wall of the movable contact spring 22 and the second groove bottom serves to hinder the movement of the arc toward the direction in which the pair of stationary contact terminals 21 approach each other.

Because the second arc isolation groove 223 has the second groove wall and the second groove bottom which are connected with each other, the joint between the second groove wall and the side wall of the movable reed 22 is an edge, the arc moves to the edge to form an arc gathering, meanwhile, the height difference between the side wall of the movable reed 22 and the second groove bottom is a drop of the arc along the transfer path of the side wall of the movable reed 22, the drop makes the arc not easy to move towards the central line of the length direction of the movable reed 22, and the arc extinguishing effect is improved by utilizing the combination of the edge and the drop.

In one embodiment, the second arc separation groove 223 is a through groove along the axial direction of the stationary contact terminal 21.

If the second arc-separating groove 223 extends along the length direction of the movable contact spring 22, the arc can be transferred along the portion of the side wall of the movable contact spring 22 where the second arc-separating groove 223 is not provided, and there is a risk of arc shorting. For this reason, the second arc separation groove 223 is provided as a through groove in the axial direction of the stationary contact leading-out terminals 21, and since the through groove is provided in the height direction penetrating the movable contact spring 22, after the arc enters the second arc separation groove 223, the transfer path of the arc toward the direction in which the pair of stationary contact leading-out terminals 21 approach each other is completely cut off.

In one embodiment, as shown in fig. 30-33, the arc isolating structure is an arc isolating protrusion 224 provided on the side wall of the movable contact 22.

The connection part between the arc isolation protrusion 224 and the side wall of the movable reed 22 is an edge, the arc moves to the edge to form an arc aggregation, meanwhile, the side wall of the movable reed 22 and the arc isolation protrusion 224 have a height difference, and the height difference enables the arc not to easily cross the height difference and reduce the risk of moving towards the central line of the length direction of the movable reed 22, so that the arc extinguishing effect is improved.

It will be appreciated that the arc isolation structure provided in this embodiment is a second arc isolation groove 223 or an arc isolation protrusion 224, and in some other embodiments, the arc isolation structure may also have both a second arc isolation groove 223 and an arc isolation protrusion 224, for example, one part of the arc isolation structures is the second arc isolation groove 223, and the other part is the arc isolation protrusion 224, and its specific form may be adjusted according to actual production situations.

Example five

This embodiment is similar to the first embodiment, and differs only in the specific structure of the movable contact spring 22 and further in the function of improving the short circuit resistance.

When the short-circuit load is large, under the action of the short-circuit current, an electric repulsive force is generated between the movable reed 22 and the stationary contact leading-out end 21 to cause the contact to spring open, so that the contact is drawn and burned violently, and even explosion can possibly occur.

For this reason, as shown in fig. 34 to 37, the relay provided in this embodiment further includes a short circuit resisting assembly 3, and the short circuit resisting assembly 3 is disposed at least on a side of the movable reed 22 facing the stationary contact leading end 21, and generates a suction force for resisting an electric repulsive force between the movable reed 22 and the stationary contact leading end 21 when a large fault current occurs to the movable reed 22.

The anti-short circuit assembly 3 may also be referred to as a short circuit ring disposed between the pair of stationary contact terminals 21, and for a high voltage dc relay, the first arc-isolating member 7 may prevent the arc from being attracted by the anti-short circuit assembly 3 to attract the arc in a direction in which the pair of stationary contact terminals 21 approach each other, thereby preventing insulation between the contacts from being reduced or arc shorting.

The axial direction of the stationary contact lead-out terminal 21, the length direction of the movable reed 22, and the width direction of the movable reed 22 are perpendicular to each other, and the axial direction of the stationary contact lead-out terminal 21, the length direction of the movable reed 22, and the width direction of the movable reed 22 are only representative spatial directions.

Specifically, the thrust portion 221 of the movable reed 22 is disposed between the two contact portions, the anti-short-circuit assembly 3 is disposed on the thrust portion 221 of the movable reed 22, two sides of the thrust portion 221 are planar structures, and the bilateral planes of the thrust portion 221 provide convenience and reliability for mounting the anti-short-circuit assembly 3, and the anti-short-circuit assembly 3 is used for resisting electric repulsive force between the movable reed 22 and the stationary contact leading end 21.

In one embodiment, as shown in fig. 34 to 38, the short circuit prevention assembly 3 includes an upper magnetizer 31 and a lower magnetizer 32, and the upper magnetizer 31 is disposed on a side of the movable contact 22 facing the stationary contact terminal 21. The lower magnetizer 32 is at least partially arranged on one side of the movable reed 22 away from the stationary contact leading-out end 21, and a magnetic conduction loop is formed between the upper magnetizer 31 and the lower magnetizer 32. The upper magnetizer 31 and the lower magnetizer 32 can be made of materials such as iron, cobalt, nickel, alloys thereof and the like.

The upper magnetizer 31 is disposed at a side of the thrust portion 221 facing the stationary contact lead-out end 21, the lower magnetizer 32 is disposed at a side of the thrust portion 221 facing away from the stationary contact lead-out end 21, that is, the lower magnetizer 32 is fixed below the thrust portion 221 of the movable reed 22, a magnetic conductive loop can be formed between the upper magnetizer 31 and the lower magnetizer 32, and the lower magnetizer 32 can move together with the movable reed 22 in a direction facing the stationary contact lead-out end 21. When the movable reed 22 has a large fault current, because the upper magnetizer 31 is positioned above the movable reed 22, the lower magnetizer 32 is positioned below the movable reed 22, which is equivalent to that the movable reed 22 is clamped between the upper magnetizer 31 and the lower magnetizer 32, when the upper magnetizer 31 generates suction force to the lower magnetizer 32, the suction force plays a role in attracting and pulling the movable reed 22 and is used for resisting electric repulsive force generated between the movable reed 22 and the fixed contact leading-out end 21 due to fault current, so that the condition of arc explosion caused by mutual disconnection between the movable reed 22 and the fixed contact leading-out end 21 is avoided, and the contact reliability and safety of the movable reed 22 and the fixed contact leading-out end 21 are ensured.

In one embodiment, the upper magnetizer 31 may have a linear structure, the upper magnetizer 31 is correspondingly disposed at a position between two contact portions of the movable reed 22, and the upper magnetizer 31 may extend along the width direction of the movable reed 22 for matching and correspondence of the upper magnetizer 31 and the lower magnetizer 32. The lower magnetizer 32 has a U-shaped structure, and an opening of the lower magnetizer 32 is arranged towards the movable reed 22, so that two side arms of the lower magnetizer 32 extend towards the direction of the upper magnetizer 31, and thus the two side arms of the lower magnetizer 32 can be respectively close to or contact with two ends of the upper magnetizer 31, so as to form a surrounding magnetic conductive ring on the movable reed 22 along the width thereof. Since the contact portions of both ends of the movable reed 22 in the length direction thereof are movable contacts, the surrounding magnetic ring formed in the width direction of the movable reed 22 does not interfere, and when a large fault current occurs in the movable reed 22, electromagnetic attraction force in the pressure direction of the movable contacts is generated so as to resist electric repulsive force generated between the movable reed 22 and the stationary contact leading-out end 21 due to the fault current.

It should be noted that, the U-shaped bracket 42 may be fixedly connected to the upper magnetizer 31, the lower magnetizer 32 is connected to the bottom of the movable reed 22, the movable reed 22 and the lower magnetizer 32 form a movable member, and the short-circuit resisting assembly 3 and the movable reed 22 are disposed between the U-shaped bracket 42 and the push rod unit 41. Of course, in other embodiments, this may be the case.

Example six

This embodiment is similar to the fifth embodiment except for the detailed structures of the movable contact spring 22 and the short circuit prevention member 3.

As shown in fig. 39-41, the thrust portion 221 of the movable spring 22 provided in this embodiment is provided with a through hole 2211, and the lower magnetizer 32 is at least partially inserted into the through hole 2211.

In this way, the thrust portion 221 of the movable reed 22 provides a mounting and fixing position for the lower magnetizer 32 to enhance the fixing effect between the movable reed 22 and the lower magnetizer 32. Because the lower magnetizer 32 has a U-shaped structure, the opening of the lower magnetizer 32 is arranged towards the thrust part 221 of the movable reed 22, one side arm of the lower magnetizer 32 is wrapped on the long side of the movable reed 22, and the other side arm is penetrated through the through hole 2211.

In one embodiment, the number of the upper magnetizers 31 and the lower magnetizers 32 is plural, the plural upper magnetizers 31 and the plural lower magnetizers 32 are correspondingly arranged, and one side, close to each other, of each adjacent two lower magnetizers 32 is penetrated through the through hole 2211.

The upper magnetizers 31 and the lower magnetizers 32 are correspondingly arranged to increase the magnetic attraction effect between the upper magnetizers 31 and the lower magnetizers 32, further improve the attraction and pulling action of the movable reed 22 and resist the electric repulsive force generated between the movable reed 22 and the fixed contact leading-out end 21 due to fault current.

For example, the number of the upper magnetizers 31 and the lower magnetizers 32 is two, the side walls of the two lower magnetizers 32 close to each other are simultaneously penetrated in the through holes 2211, and the two lower magnetizers 32 are installed by using the same through hole 2211, so that the production cost and the assembly difficulty are reduced. Of course, in other embodiments, this may be the case.

It should be noted herein that the movable reed shown in the drawings and described in the present specification is merely one example of the principles of the present utility model. It will be clearly understood by those of ordinary skill in the art that the principles of the present utility model are not limited to any details or any components of the devices shown in the drawings or described in the specification.

Claims (17)

1. The movable reed is characterized in that the movable reed is used for contacting with or separating from a pair of stationary contact leading-out ends;

the movable reed is arranged on one side of the movable reed, which faces the leading-out end of the fixed contact, and is arranged on the top surface of the movable reed, and the first arc isolation groove is used for preventing an electric arc from moving towards the direction of approaching the pair of leading-out ends of the fixed contact.

2. The movable reed according to claim 1, wherein the first arc isolation groove comprises a first groove wall and a first groove bottom which are connected with each other, and the extending direction of the first groove wall is arranged at an included angle with the length direction of the movable reed;

The arc moves to the connection part between the first groove wall and the top surface of the movable reed to form an arc-gathering, and the height difference between the top surface of the movable reed and the bottom of the first groove is used for preventing the arc from moving towards the direction that the pair of fixed contact leading-out ends are close to each other.

3. The movable contact spring according to claim 1, wherein a portion of the movable contact spring contacting the pair of stationary contact leading-out ends is a first contact portion, and the first arc-isolating groove is provided between inner edges of the first contact portion.

4. A movable contact spring according to claim 3, wherein said first arc-isolating groove is a through groove along a width direction of said movable contact spring.

5. The movable contact spring according to claim 3, wherein the number of the first arc isolating grooves is one, and the parts of the movable contact spring on two sides of the first arc isolating grooves along the length direction of the movable contact spring are respectively correspondingly abutted against a pair of stationary contact leading-out ends; the distance between the two side edges of the first arc isolation groove along the length direction of the movable reed is smaller than or equal to the distance between the inner edges of the first contact part.

6. The movable contact spring according to claim 3, wherein the number of the first arc-isolating grooves is two, the two first arc-isolating grooves are arranged corresponding to the pair of stationary contact leading-out ends, and the distance between the outer edges of the two first arc-isolating grooves along the length direction of the movable contact spring is smaller than or equal to the distance between the inner edges of the first contact portions.

7. The movable contact spring according to claim 6, wherein the first arc isolating slot is at least one of a linear structure, a convex structure and an X-shaped structure.

8. The movable contact spring according to claim 6, wherein the first arc-isolating slot has an arc-shaped structure, and the first arc-isolating slot is annularly arranged around the leading-out end of the stationary contact.

9. The movable contact spring according to any one of claims 1 to 8, wherein a side wall of the movable contact spring is provided with an arc-shielding structure for blocking movement of the arc toward a direction in which a pair of the stationary contact terminals approach each other.

10. The movable contact spring according to claim 9, wherein a portion of the movable contact spring contacting the pair of stationary contact leading-out ends is a first contact portion, and the arc-isolating structure is disposed between inner edges of the first contact portion.

11. The movable contact spring according to claim 9, wherein the arc isolation structure is a second arc isolation groove arranged on the side wall of the movable contact spring; and/or the number of the groups of groups,

the arc isolation structure is an arc isolation protrusion arranged on the side wall of the movable reed.

12. The movable contact spring according to claim 11, wherein said second arc-isolating groove comprises a second groove wall and a second groove bottom connected to each other;

The electric arc moves to the connection position between the second groove wall and the movable reed side wall to form an arc aggregation, and the height difference between the movable reed side wall and the second groove bottom is used for preventing the electric arc from moving towards the direction that the pair of fixed contact leading-out ends are close to each other.

13. The movable contact spring according to claim 11, wherein said second arc-isolating groove is a through groove along an axial direction of said stationary contact leading-out end.

14. The movable contact spring according to claim 10, wherein the number of the arc isolating structures is plural, and the plurality of the arc isolating structures are arranged on two sides of the movable contact spring along the length direction of the movable contact spring; and/or the number of the groups of groups,

the number of the arc isolation structures is multiple, and the arc isolation structures are arranged on two sides of the movable reed along the width direction of the movable reed.

15. A contact unit comprising a pair of stationary contact terminals and the movable contact spring according to any one of claims 1 to 14 for contacting or separating from the pair of stationary contact terminals.

16. The contact unit of claim 15, further comprising a short circuit prevention member disposed at least on a side of the movable contact spring toward the stationary contact lead-out end, the movable contact spring generating a suction force for resisting an electromotive repulsive force between the movable contact spring and the stationary contact lead-out end when a large current is failed.

17. A relay comprising a contact unit according to any one of claims 15-16.