Relay

Abstract

The invention relates to a relay. At least one of the outer side part of a first contact part and the outer side part of a second contact part is provided with a first avoiding part for avoiding each other. When the first contact part and the second contact part are separated from each other or are in contact with each other so that an electric arc is generated at the contact unit, a magnetic field formed by the first permanent magnet can play a traction role on the electric arc, and arc blowing and arc discharge effects are achieved. The electric arc moves along the contact surface of the contact unit, when the electric arc moves to the first avoiding part, the first avoiding part can play a role in separating, lengthening and blocking the electric arc, and the arcing time is shortened. Besides, the first avoiding part is arranged according to the magnetic blow-out path, so that the positions of the first contact part and the second contact part are relatively controllable, meanwhile, the contact area is relatively small, the position of an arcing point is more controlled, and the arc isolation effect is obvious. Besides, the defects that the inner cavity is ablated by an electric arc and the relay explodes and the like can be effectively avoided, the product performance can still be ensured even under the condition of high load, and the failure probability of the product can be reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electric control devices, and in particular to a relay. Background Art

[0002] A relay is an electronic control device with a control system (also known as an input circuit) and a controlled system (also known as an output circuit). It is commonly used in automatic control circuits. A relay is essentially an "automatic switch" that uses a smaller current to control a larger current. Therefore, it performs functions such as automatic regulation, safety protection, and circuit switching in circuits. A high-voltage DC relay is a type of relay. It consists of a pair of stationary contacts and a moving contact. The moving contact's ends, along its length, mate with a pair of stationary contacts to connect and disconnect the load.

[0003] The principle of disconnecting the load of the high-voltage DC relay is to generate a directional magnetic blowing magnetic field by setting a permanent magnet. When the moving and static contacts separate and an arc is generated, the arc is rapidly elongated by the magnetic blowing magnetic field until the arc is disconnected. The disconnection of the arc realizes the disconnection of the load and the extinguishing of the arc at the same time.

[0004] In the related art, the inner cavity of the relay is made of arc-resistant plastic parts. The plastic parts can prevent the arc from contacting the permanent magnet, thereby protecting the permanent magnet. However, when the inner cavity space of the relay is limited, especially when the load is higher, the arcing time is longer, and the arc is more likely to contact the plastic parts and burn the inner cavity, causing serious carbon deposits in the inner cavity, which in turn leads to various problems such as contact non-conduction and poor voltage resistance of the push component card, resulting in low product performance. In addition, when the inner cavity is burned through, the arc contacts the permanent magnet, causing the permanent magnet to demagnetize, increasing the arcing time and causing problems such as relay explosion. The product has a high risk of failure. Summary of the Invention

[0005] Based on this, it is necessary to overcome the defects of the existing technology and provide a relay that can effectively realize arc blowing, arc stretching, arc isolation and arc breaking, and can reduce the arcing time to meet high load capacity requirements.

[0006] A relay comprising:

[0007] A contact assembly, the contact assembly comprising a stationary contact lead-out terminal and a movable spring, the stationary contact lead-out terminal being provided with a first contact portion, the movable spring being provided with a second contact portion corresponding in position to the first contact portion; at least one of the first contact portion and the second contact portion being provided with a first avoidance portion for avoiding each other; and

[0008] A first permanent magnet is disposed around the movable spring.

[0009] In one embodiment, the first avoidance portion includes one or more combinations of avoidance grooves, avoidance holes, and avoidance gaps.

[0010] In one embodiment, the avoidance groove is a blind groove or a through groove.

[0011] In one embodiment, the avoidance groove is a groove body with four sides closed; or the avoidance groove is a groove body with four sides not closed.

[0012] In one embodiment, the outline of the first avoidance portion is rectangular, trapezoidal, triangular, circular, semicircular, U-shaped or Ω-shaped.

[0013] In one embodiment, the first avoidance portion is disposed at an outer portion of the first contact portion; and / or the first avoidance portion is disposed at an outer portion of the second contact portion.

[0014] In one embodiment, a plurality of first avoidance portions are provided at an outer portion of the first contact portion, and the plurality of first avoidance portions are arranged in sequence along the width direction of the first contact portion; and / or a plurality of first avoidance portions are provided at an outer portion of the second contact portion, and the plurality of first avoidance portions are arranged in sequence along the width direction of the second contact portion.

[0015] In one embodiment, one first avoidance portion is provided at the outer portion of the first contact portion, and the first avoidance portion is provided at the middle portion or any one end of the first contact portion in the width direction of the movable spring piece; and / or one first avoidance portion is provided at the outer portion of the second contact portion, and the first avoidance portion is provided at the middle portion or any one end of the second contact portion in the width direction of the movable spring piece.

[0016] In one embodiment, a second avoidance portion is provided on the movable spring piece, and the second avoidance portion is arranged on a side of the second contact portion close to the central axis of the movable spring piece.

[0017] In one embodiment, opposite ends of the second avoidance portion extend to two opposite sides of the movable spring along the width direction thereof.

[0018] In one embodiment, the second avoidance portion is configured as a avoidance groove, and the depth of the second avoidance portion increases from its middle position to a position at either end.

[0019] In one embodiment, the second avoidance portion is configured as a avoidance groove, a avoidance hole, or a avoidance gap; and the contour shape of the second avoidance portion is arc-shaped, rectangular, trapezoidal, triangular, circular, semicircular, U-shaped, or Ω-shaped.

[0020] In one embodiment, at least one of the first contact portion and the second contact portion is provided with a third avoidance portion for avoiding each other, and the third avoidance portion is located on a side of the first avoidance portion away from the magnetic field direction of the first permanent magnet.

[0021] In one embodiment, the opposite ends of the third avoidance portion on the first contact portion extend to two opposite sides in the width direction of the first contact portion respectively; and / or the opposite ends of the third avoidance portion on the second contact portion extend to two opposite sides in the width direction of the second contact portion respectively.

[0022] In one embodiment, the third avoidance portion is configured as a avoidance groove, a avoidance hole, or a avoidance gap; and the contour shape of the third avoidance portion is arc-shaped, rectangular, trapezoidal, triangular, circular, semicircular, U-shaped, or Ω-shaped.

[0023] In one embodiment, there are two static contact lead terminals, one movable spring, and each of the two opposite ends of the movable spring along the length direction is provided with a second contact portion; there are two groups of first permanent magnets, and the two groups of first permanent magnets are respectively arranged on the outer sides of the opposite ends of the movable spring along the length direction, and the two groups of first permanent magnets are respectively provided with a one-to-one correspondence with the two second contact portions.

[0024] In one embodiment, the relay further includes a second permanent magnet, which is disposed between the two static contact leads, and the second permanent magnet and the first permanent magnet have opposite magnetic properties on two surfaces facing each other.

[0025] In one embodiment, the number of the first permanent magnets is adjustable; and / or the magnetic force of the first permanent magnets is stronger than the magnetic force of the second permanent magnets.

[0026] In the above-mentioned relay, when the first contact portion and the second contact portion are separated from each other or an arc is generated at the contact point, the magnetic field formed by the first permanent magnet can pull the arc, achieving the effect of blowing and stretching the arc. The arc moves along the contact surface, and when the arc moves to the first avoidance portion, the first avoidance portion can separate, lengthen and block the arc, thereby reducing the arc burning time. In addition, since the first avoidance portion is set according to the magnetic blowing path, the positions of the first contact portion and the second contact portion are relatively controllable, and the contact area is relatively small, so that the position of the arc starting point is more controlled, and the arc isolation effect is obvious. In addition, it can effectively avoid defects such as arc burning the inner cavity and causing the relay to explode. Even under high load conditions, the product performance can still be guaranteed and the probability of product failure can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a structural diagram of a relay according to an embodiment of the present application.

[0028] Figure 2 This is a structural diagram of a relay according to another embodiment of the present application.

[0029] Figure 3 for Figure 1 The direction diagram of the arc in one embodiment of the relay is shown.

[0030] Figure 4 for Figure 1 The direction diagram of the arc in another embodiment of the relay is shown.

[0031] Figure 5 for Figure 1 The direction diagram of the arc in another embodiment of the relay is shown.

[0032] Figure 6 for Figure 1 The direction diagram of the arc in another embodiment of the relay is shown.

[0033] Figure 7 for Figure 2 Direction diagram of the arc in one embodiment of the relay shown.

[0034] Figure 8 This is a structural diagram of the movable spring of the first embodiment of the present application.

[0035] Figure 9 This is a structural diagram of the movable spring according to the second embodiment of the present application.

[0036] Figure 10 This is a structural diagram of the movable spring according to the third embodiment of the present application.

[0037] Figure 11 This is a structural diagram of the movable spring according to the fourth embodiment of the present application.

[0038] Figure 12 for Figure 11 Another perspective structural diagram of the dynamic reed shown.

[0039] Figure 13 for Figure 12 Cross-sectional structural diagram at EE.

[0040] Figure 14 for Figure 12 Cross-sectional structural diagram at FF.

[0041] Figure 15 This is a structural diagram of the movable spring according to the fifth embodiment of the present application.

[0042] Figure 16 This is a structural diagram of the movable spring according to the sixth embodiment of the present application.

[0043] Figure 17This is a structural diagram of the movable spring according to the seventh embodiment of the present application.

[0044] Figure 18 This is a structural diagram of the movable spring according to the eighth embodiment of the present application.

[0045] Figure 19 This is a structural diagram of the movable spring according to the ninth embodiment of the present application.

[0046] Figure 20 This is a structural diagram of the movable spring according to the tenth embodiment of the present application.

[0047] Figure 21 This is a structural diagram of the movable spring according to the eleventh embodiment of the present application.

[0048] Figure 22 This is a structural diagram of the movable spring according to the twelfth embodiment of the present application.

[0049] Figure 23 This is a structural diagram of the movable spring according to the thirteenth embodiment of the present application.

[0050] Figure 24 This is a structural diagram of the movable spring according to the fourteenth embodiment of the present application.

[0051] Figure 25 This is a structural diagram of the movable spring according to the fifteenth embodiment of the present application.

[0052] Figure 26 This is a structural diagram of the movable spring according to the sixteenth embodiment of the present application.

[0053] Figure 27 This is a structural diagram of the movable spring according to the seventeenth embodiment of the present application.

[0054] Figure 28 This is a structural diagram of the movable spring according to the eighteenth embodiment of the present application.

[0055] Figure 29 This is a structural diagram of the movable spring according to the nineteenth embodiment of the present application.

[0056] Figure 30 This is a structural diagram of the movable spring of the twentieth embodiment of the present application.

[0057] Figure 31 This is a structural diagram of the movable spring according to the twenty-first embodiment of the present application.

[0058] Figure 32 This is a structural diagram of the movable spring according to the twenty-second embodiment of the present application.

[0059] Figure 33 This is a structural diagram of a relay according to another embodiment of the present application.

[0060] Figure 34 for Figure 33Another perspective structural diagram of the relay shown.

[0061] Figure 35 for Figure 33 Another perspective structural diagram of the relay shown.

[0062] Figure 36 for Figure 33 Bottom view of the static contact terminals in the relay shown.

[0063] Figure 37 This is a structural diagram of a relay according to another embodiment of the present application.

[0064] Figure 38 for Figure 37 Another perspective structural diagram of the relay shown.

[0065] Figure 39 for Figure 37 Another perspective structural diagram of the relay shown.

[0066] Figure 40 This is a structural diagram of the arrangement of the first permanent magnet according to an embodiment of the present application.

[0067] Figure 41 This is a structural diagram of the arrangement of the first permanent magnet according to another embodiment of the present application.

[0068] Figure 42 This is a cross-sectional structural diagram of a relay according to an embodiment of the present application.

[0069] 10. Contact assembly; 11. Static contact lead-out terminal; 111. First contact portion; 12. Moving spring; 121. Second contact portion; 1211. Second protruding portion; 1212. Abutting unit portion; 13. First avoidance portion; 131. Notch side; 14. Second avoidance portion; 15. Third avoidance portion; 20. Pushing assembly; 21. Coil; 22. Pushing rod; 30. First permanent magnet; 40. Second permanent magnet; 50. Inner cavity; 60. Base. DETAILED DESCRIPTION

[0070] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0071] This embodiment provides a relay, such as Figure 1 or Figure 2 and Figure 42 As shown, Figure 1and Figure 2 The schematic diagrams of the structures of the relays in two different embodiments of the present application are shown respectively. Figure 42 The cross-sectional structure diagram of the relay is shown. The relay of one embodiment includes a contact assembly 10 and a pushing assembly 20. The contact assembly 10 includes a static contact lead-out terminal 11 and a movable reed 12. The pushing assembly 20 is connected to the movable reed 12, and the pushing assembly 20 is used to push the movable reed 12 to move so that the static contact lead-out terminal 11 and the movable reed 12 contact or separate with each other. Optionally, the pushing assembly 20 includes a coil 21 and a pushing rod 22, etc. The magnetic field generated when the coil 21 is energized can drive the pushing rod 22 to move, and the pushing rod 22 correspondingly drives the movable reed 12 to contact or separate with the static contact lead-out terminal 11. Among them, the pushing assembly 20 can also be various other structural forms, as long as it can achieve the purpose of pushing the movable reed 12, which is not limited here. In addition, the specific structure of the pushing assembly 20 is prior art, which is recorded in detail in the prior art and will not be repeated here.

[0072] When the movable spring 12 and the static contact lead-out terminal 11 are in contact, the movable spring 12, the static contact lead-out terminal 11 and the load are connected to form a path, thereby achieving connection with the load; conversely, when the movable spring 12 and the static contact lead-out terminal 11 are separated, the movable spring 12 and the static contact lead-out terminal 11 are disconnected from each other.

[0073] See also Figure 1 and Figure 3 For example, the static contact lead-out terminal 11 is provided with a first contact portion 111, and the movable spring piece 12 is provided with a second contact portion 121 corresponding to the position of the first contact portion 111. The first contact portion 111 and the second contact portion 121 cooperate with each other to form a contact unit. In other words, the contact unit includes a first contact portion 111 and a second contact portion 121 that contact and cooperate with each other. The number of contact units depends on the number of the first contact portion 111 and the second contact portion 121, and can be one group, two groups, three groups or more groups, and the specific number is not limited. In order to facilitate the description and understanding of the present invention, this embodiment is specifically expanded by taking the number of two contact units as an example. Of course, the number of contact units can also be flexibly adjusted and set according to actual production needs.

[0074] It should be noted that the "positional correspondence" in the positional correspondence between the first contact portion 111 and the second contact portion 121 means that the first contact portion 111 and the second contact portion 121 are positioned relative to each other along the movement direction of the movable spring 12; in other words, along the movement direction of the movable spring 12, at least a portion of the projection area of the first contact portion 111 on the movable spring 12 overlaps with the second contact portion 121.

[0075] It should be noted that the "first contact portion 111" can be a "part of the static contact lead-out terminal 11", that is, the "first contact portion 111" and the "other parts of the static contact lead-out terminal 11" are integrally formed; it can also be an independent component that can be separated from the "other parts of the static contact lead-out terminal 11", that is, the "first contact portion 111" can be manufactured independently and then combined with the "other parts of the static contact lead-out terminal 11" into a whole.

[0076] Similarly, the "second contact portion 121" can be "a part of the movable reed 12", that is, the "second contact portion 121" is integrally formed with the "other parts of the movable reed 12"; or it can be an independent component that is separable from the "other parts of the movable reed 12", that is, the "second contact portion 121" can be manufactured independently and then combined with the "other parts of the movable reed 12" to form a whole.

[0077] Define the arrangement direction of the two contact units as the first direction. Figure 1 As shown by the double arrow x in the second direction Figure 1 As shown by the double arrow y; the direction of movement of the dynamic spring 12 relative to the static contact lead end 11 is the third direction, the third direction is as shown Figure 1 As shown by the double arrow z in the figure; the first direction, the second direction and the third direction are perpendicular to each other, wherein the first direction, the second direction and the third direction only represent spatial directions and have no practical meaning.

[0078] Specifically, the movable spring piece 12 in this embodiment is in the shape of a sheet. The movable spring piece 12 includes, but is not limited to, straight sheets, curved sheets, straight strips, curved strips or other regular and irregular shapes, which can be adjusted and set according to actual needs. Under the premise that the movable spring piece 12 is a straight sheet, the length direction of the movable spring piece 12 is also as shown in FIG. Figure 1 As shown by the double arrow x in the figure, the width direction of the dynamic spring 12 is also as shown in FIG. Figure 1 As shown by the double arrow y in FIG, the thickness direction of the movable spring 12 is also as shown in FIG. Figure 1 In addition, when the movable spring piece 12 is set as a curved piece, it is specifically a U-shaped curved piece, such as Figure 32 As shown, the opposite ends of the movable spring 12 protrude toward the two first contact portions 111 , respectively, and the portion between the opposite ends of the movable spring 12 , that is, the middle portion of the movable spring 12 , is recessed in a direction away from the static contact lead-out terminal 11 .

[0079] When the movable spring 12 and the static contact lead-out terminal 11 are separated, an arc will be generated between the first contact portion 111 and the second contact portion 121 due to the separation. If the arc cannot be disconnected or extinguished in time, under the condition that the space of the inner cavity 50 of the relay is limited, especially when the load is higher, the arcing time is longer, and the arc is likely to contact the plastic parts and burn the inner cavity 50, causing serious carbon deposits in the inner cavity 50, thereby leading to various problems such as contact non-conduction, pushing component 20 jamming and poor voltage resistance, and low product performance; in addition, when the inner cavity 50 is burned through, the arc contacts the permanent magnet, causing the permanent magnet to demagnetize, aggravating the arcing time, and causing problems such as relay explosion, and the product has a high risk of failure.

[0080] Based on the above reasons, the present application provides a relay that can effectively realize arc blowing, arc pulling, arc isolation and arc breaking, and can reduce the arc burning time to meet the technical solution of high load capacity requirements.

[0081] Please refer to Figure 1 or Figure 2 The relay provided by one embodiment of the present application further includes a first permanent magnet 30 . The first permanent magnet 30 is disposed around the movable reed 12 .

[0082] Optionally, a polar side of the first permanent magnet 30 faces the contact unit, that is, the first contact portion 111 and the second contact portion 121 , so as to achieve arc extinguishing by utilizing the magnetic field formed by the first permanent magnet 30 .

[0083] Wherein, the movable spring piece 12 is provided with a second contact portion 121 at both ends along the length direction. The first permanent magnet 30 is provided in two groups. Figure 1 or Figure 2 The two groups of first permanent magnets 30 can be respectively arranged on the outer sides of the opposite ends of the movable spring 12 along the length direction, and the two groups of first permanent magnets 30 are respectively arranged in a one-to-one correspondence with the two contact units. The contact units and the corresponding first permanent magnets 30 are arranged close to each other. Of course, the two groups of first permanent magnets 30 can also be arranged in other ways, for example, see Figure 40 and Figure 41 The two groups of first permanent magnets 30 are respectively arranged on any diagonal line of the movable spring 12 .

[0084] In addition, at least one of the first contact portion 111 and the second contact portion 121 is provided with a first avoidance portion 13. Thus, the first avoidance portion 13 is located on the magnetic blowing path, which can facilitate isolating, lengthening and interrupting the arc and reducing the arcing time.

[0085] For example, see Figures 37 to 39 When the first contact portion 111 is provided with a first avoidance portion 13, the first avoidance portion 13 is, for example, provided at an outer portion of the first contact portion 111; Figures 1 to 3 When the second contact portion 121 is provided with a first avoidance portion 13, the first avoidance portion 13 is, for example, provided at an outer portion of the second contact portion 121; Figures 33 to 36 When the first contact portion 111 and the second contact portion 121 are both provided with the first avoidance portion 13 , the first avoidance portion 13 of the first contact portion 111 and the second contact portion 121 are both located at their respective outer portions.

[0086] It should be noted that, in this embodiment, the outer portion of the first contact portion 111 refers to the side of the first contact portion 111 away from the central axis of the movable spring piece 12; conversely, the inner portion of the first contact portion 111 refers to the side of the first contact portion 111 close to the central axis of the movable spring piece 12. Similarly, the outer portion of the second contact portion 121 refers to the side of the second contact portion 121 away from the central axis of the movable spring piece 12; conversely, the inner portion of the second contact portion 121 refers to the side of the second contact portion 121 close to the central axis of the movable spring piece 12. The central axis of the movable spring piece is as shown in FIG. Figure 1 As shown by the dotted line O in FIG.

[0087] It should be noted that, for each contact unit, when the first contact portion 111 and the second contact portion 121 contact each other, it can be point contact, and the number of contact points is not limited to one, for example, it can be two, three or four or more; it can also be line contact or surface contact; it can also be any combination of point contact, line contact and surface contact, which is not limited here and can be set according to actual needs.

[0088] The contact surface of the first contact portion 111 facing the second contact portion 121 can be configured as an arc surface, a plane or other irregular shapes, and can be adjusted and configured according to actual needs.

[0089] It should be noted that when there are two contact units, the shapes and sizes of the first avoidance portions 13 on the two first contact portions 111 can be consistent with each other or different from each other; the shapes and sizes of the first avoidance portions 13 on the two second contact portions 121 can be consistent with each other or different from each other, which are not limited here and can be flexibly adjusted and set according to actual needs.

[0090] In the above-mentioned relay, when the first contact portion 111 and the second contact portion 121 are separated from each other or contact each other so that an arc is generated at the contact unit, the magnetic field formed by the first permanent magnet 30 can pull the arc, achieving the effect of blowing and stretching the arc. The arc moves along the contact surface of the contact unit. When the arc moves to the first avoidance portion 13, the first avoidance portion 13 can separate, stretch and block the arc, thereby reducing the arc burning time. In addition, since the first avoidance portion 13 is set according to the magnetic blowing path, the positions of the first contact portion 111 and the second contact portion 121 are relatively controllable, and the contact area is relatively small, so that the position of the arc starting point is more controlled, and the position of the arc starting point can be controlled, so that the arc isolation effect is obvious. In addition, it can effectively avoid defects such as arc burning the inner cavity 50 and causing the relay to explode. Even under high load conditions, product performance can still be guaranteed and the probability of product failure can be reduced.

[0091] For example, the first avoidance portion 13 includes but is not limited to one or more combinations of avoidance grooves, avoidance holes, and avoidance notches, as long as it can avoid the first contact portion 111 and the second contact portion 121 from contacting each other at the position of the first avoidance portion 13. Specifically, this embodiment takes the first avoidance portion 13 as an example of an avoidance groove, see Figures 8 to 32 Optionally, the avoidance slot can be a blind slot, such as Figures 8 to 10 and Figures 15 to 23 Of course, the avoidance groove can also be set as a through groove, such as Figures 26 to 30 As shown, the avoidance groove penetrates the movable spring piece 12 along the thickness direction of the movable spring piece 12.

[0092] Based on any of the above embodiments, the avoidance groove can be a groove body with four sides closed, such as Figure 31 Of course, the avoidance groove can also be a non-enclosed groove body on all sides.

[0093] It should be noted that the "all-around closed" in the all-around closed trough body means that a point is selected on the side wall of the trough body as the starting point, and the movement is made circumferentially along the side wall of the trough body from the starting point, and eventually it can return to the starting point; conversely, the "all-around non-closed" in the all-around non-closed trough body means that a point is selected on the side wall of the trough body as the starting point, and the movement is made circumferentially along the side wall of the trough body from the starting point, and eventually it cannot return to the starting point.

[0094] When the avoidance groove is configured as a non-enclosed groove body, the notch side 131 of the avoidance groove may be located at the outer edge of the contact unit. Figures 8 to 10 、 Figures 15 to 23 and Figures 26 to 30 Of course, the notch side 131 of the avoidance groove can also be provided at other edge positions of the contact unit, which is not specifically limited here.

[0095] The outer edge of the contact unit refers to the edge of the contact unit that faces away from the central axis of the movable spring 12. Correspondingly, the outer edge of the first contact portion 111 refers to the edge of the first contact portion 111 that faces away from the central axis of the movable spring 12, and the outer edge of the second contact portion 121 refers to the edge of the second contact portion 121 that faces away from the central axis of the movable spring 12.

[0096] Based on any of the above embodiments, the contour shape of the first avoiding portion 13 includes but is not limited to regular shapes such as polygon, circle, semicircle, U-shape or Ω-shape, and other irregular shapes. Among them, polygon includes but is not limited to rectangle, trapezoid or triangle, etc.

[0097] For example, when a first avoidance portion 13 is provided on the outer portion of the first contact portion 111, a plurality of first avoidance portions 13 are provided on the outer portion of the first contact portion 111. The plurality of first avoidance portions 13 are arranged in sequence along the width direction of the movable spring piece 12. The shapes and sizes of the various first avoidance portions 13 can be consistent or different from each other. With this arrangement, the first contact portion 111 has multiple arc-breaking and arc-isolating functions along the width direction of the movable spring piece 12, thereby improving the arc-isolating effect. In addition, the first avoidance portion 13 segments the contact portion in which it is located, which inevitably results in multiple groups of contact points. The multiple groups of contact points have a shunting effect, which can reduce the contact resistance and thus reduce the temperature rise.

[0098] On the basis of the aforementioned embodiment, the number of the first avoidance portions 13 is specifically two, and the two first avoidance portions 13 are arranged on two opposite sides of the movable spring piece 12 in the width direction. In this way, a first protrusion protruding toward the first permanent magnet 30 is provided in the middle position of the outer portion of the first contact portion 111. The two first avoidance portions 13 are respectively located on opposite sides of the first protrusion in the width direction. In this way, when the contact unit is closed, the first protrusion is in electrical contact with the second contact portion 121, and the two first avoidance portions 13 can avoid the second contact portion 121, so that the arc generated by the first protrusion will quickly enter the air, thereby achieving a rapid arc breaking and arc isolation effect.

[0099] For example, when the outer portion of the second contact portion 121 is provided with a first avoidance portion 13, the outer portion of the second contact portion 121 is provided with a plurality of first avoidance portions 13. The plurality of first avoidance portions 13 are arranged in sequence along the width direction of the movable spring piece 12, as shown in FIG. Figure 29 The arrangement shown can of course also be as follows Figure 24 With such arrangement, the second contact portion 121 has multiple arc breaking and arc isolating functions along its width direction, thereby improving the arc isolating effect.

[0100] See also Figure 24 and Figure 25On the basis of the above-mentioned embodiment, the number of the first avoidance portions 13 is specifically two, and the two first avoidance portions 13 are arranged on two opposite sides of the second contact portion 121 along the width direction of the movable spring piece 12. In this way, a second protrusion 1211 protruding toward the first permanent magnet 30 is provided in the middle position of the outer portion of the second contact portion 121. The two first avoidance portions 13 are respectively located on both sides of the second protrusion 1211 along the width direction. In this way, when the contact unit is closed, the second protrusion 1211 is in electrical contact with the first contact portion 111, and the two first avoidance portions 13 can avoid the first contact portion 111, so that the arc generated by the second protrusion 1211 will quickly enter the air, thereby achieving the effect of quickly breaking the arc and isolating the arc.

[0101] For example, the first relief portion 13 on the outer side of the first contact portion 111 is not limited to the multiple portions as described in the above embodiment; it can also be provided as a single portion. Furthermore, when a single first relief portion 13 is provided on the outer side of the first contact portion 111, the specific location of the first relief portion 13 on the outer side of the first contact portion 111 is not limited and can be flexibly adjusted and positioned according to actual needs. Alternatively, the first relief portion 13 can be positioned in the middle or at either end of the first contact portion 111 along the width of the movable spring 12, thereby achieving arc interruption, arc isolation, and arc extinguishing functions.

[0102] Similarly, the first avoidance portion 13 on the outer side of the second contact portion 121 is not limited to being multiple as in the above embodiment, and may also be set to one. In addition, when the first avoidance portion 13 on the outer side of the second contact portion 121 is set to one, the specific setting position of the first avoidance portion 13 on the outer side of the second contact portion 121 is not limited and can be flexibly adjusted and set according to actual needs. Optionally, as Figures 8 to 10 and Figures 15 to 21 , the first avoidance portion 13 can be provided at the middle portion of the second contact portion 121 along the width direction. Of course, the first avoidance portion 13 can also be provided at any end of the second contact portion 121 along the width direction, such as Figure 22 and Figure 23 As shown, the arc breaking, arc isolation and arc extinguishing functions can be realized.

[0103] Among them, such as Figures 8 to 10 and Figures 15 to 21When the first avoidance portion 13 is provided in the middle portion of the second contact portion 121 along the width direction, that is, the first avoidance portion 13 is provided in the middle portion of the outer portion of the second contact portion 121 along the width direction, and the two side portions along the width direction are respectively two abutting unit portions 1212, and the first avoidance portion 13 is located between the two abutting unit portions 1212. The surfaces of the two abutting unit portions 1212 can be provided flush, so that when the contact unit is conductive, the two abutting unit portions 1212 can both be electrically contacted and conductive with the first contact portion 111, playing the role of reducing the contact resistance in parallel. Of course, the surfaces of the two abutting unit portions 1212 can also have a height difference along the thickness direction of the movable spring piece 12, and the height difference can be, for example, 0.1mm to 0.3mm, specifically, for example, 0.1mm, 0.2mm or 0.3mm, etc. Thus, when the contact unit is closed, one of the contact unit portions 1212 is in electrical contact with the first contact portion 111 , while the other contact unit portion 1212 is not in electrical contact with the first contact portion 111 , thereby achieving control over the position of the arc starting point.

[0104] See also Figure 1 、 Figure 3 and Figure 4 In order to make the principle of the first avoidance portion 13 clearer, this embodiment takes two contact units as an example, and the two arc starting points are respectively at point B and point C as an example to explain the specific arc breaking and arc isolation principles. When the two contact units are disconnected synchronously, the arcs at the two arc starting points will be blown away in the diagonal direction under the guidance of the first permanent magnet 30. Figure 3 , the arc at point B extends into the air along the lower left, as shown in Figure 3 The arc at point C extends into the air in an upward and right-hand direction, as shown in FIG. Figure 3 The arc generated at point B and point C enters the air, thus achieving arc breaking and arc extinguishing. Figure 4 When the current direction is changed, that is, the current direction is reversed, the arc direction at point B changes accordingly, for example, extending obliquely to the upper left, as shown in FIG. Figure 4 The arc generated at point B needs to cross the first avoidance portion 13 and will be interrupted by the first avoidance portion 13. In addition, the arc direction at point C changes accordingly, for example, extending obliquely to the lower right, as shown in FIG. Figure 4 In the direction indicated by the dotted arrow at point C, the arc generated at point C needs to cross the first avoidance portion 13 and will be interrupted and isolated by the first avoidance portion 13.

[0105] See also Figure 1 、 Figure 5 and Figure 6 The two arc starting points can also be, for example, point A and point D. When the two contact units are disconnected synchronously, similarly, the arcs at the two arc starting points will be blown away in the diagonal direction under the guidance of the first permanent magnet 30. Figure 5 , the arc at point A extends into the air along the upper left angle, as shown in Figure 5 The arc at point D extends into the air in a downward and right-hand direction, as shown in FIG. Figure 5 The arcs generated at point A and point D enter the air, thus achieving arc breaking and arc extinguishing. Figure 6 When the current direction is changed, that is, the current direction is reversed, the arc direction at point A changes accordingly, for example, extending obliquely to the lower left, as shown in Figure 6 The arc generated at point A needs to cross the first avoidance portion 13 and will be interrupted by the first avoidance portion 13. In addition, the direction of the arc at point D changes accordingly, for example, extending obliquely to the upper right, as shown in FIG. Figure 6 In the direction indicated by the dotted arrow at point D, the arc generated at point D needs to cross the first avoidance portion 13 and will be interrupted and isolated by the first avoidance portion 13.

[0106] It can be seen that the first avoidance portion 13 is located close to the arc starting point, and can promptly and quickly break, isolate and extinguish the arc generated at the arc starting point, thereby preventing the arc from burning the inner cavity 50 or even burning through the inner cavity 50, and preventing the arc from contacting the first permanent magnet 30 and causing demagnetization defects.

[0107] In the case where the arc is not controlled, or when the second permanent magnet 40 is provided, or when the contact is worn, the arc blowing direction is irregular, and may not only blow toward the outer part of the second contact portion 121, but also toward the inner part of the second contact portion 121, for example, Figure 7 Arcs are generated at points ABCD, and all arcs blow toward the inner side of the second contact portion 121. To address this, a second relief portion 14 is optionally provided on the movable spring 12. The second relief portion 14 is located inner side of the second contact portion 121. This provides the same arc isolation and rapid arc extinguishing properties, significantly reducing arcing time.

[0108] Optionally, the number of second avoidance portions 14 includes, but is not limited to, one, two, three, or more, and can be flexibly adjusted and set according to actual needs, and is not limited here. In this embodiment, the second avoidance portion 14 is specifically set to one, for example. In this way, although the arc may blow toward the inner portion of the second contact portion 121 in some cases, the length of the arc blowing toward the inner portion of the second contact portion 121 is not large. Therefore, providing a single second avoidance portion 14 can achieve the arc breaking and arc isolation functions, without the need to provide a larger number of second avoidance portions 14, thereby avoiding the defect of excessive current-carrying temperature rise caused by an excessive number of second avoidance portions 14.

[0109] Of course, as some optional solutions, the second avoidance portion 14 in this embodiment is not limited to the single one in the above embodiment, and can also be provided in multiples. Compared with providing a single second avoidance portion 14, providing multiple second avoidance portions 14 can interrupt and isolate the arc layer by layer, further improving the arc interruption and isolation effect, but it will affect the current carrying capacity and cause the temperature to increase.

[0110] For example, the opposite ends of the second avoidance portion 14 extend to two opposite sides of the movable spring piece 12 along its width direction. In this way, the second avoidance portion 14 is longer, the arc breaking and arc isolating area is larger, and the arc breaking and arc isolating effect is better.

[0111] After research, it was found that the arc is relatively easy to blow to the end portion of the second avoidance portion 14, and the arc blowing to the middle portion of the second avoidance portion 14 is relatively rare. Figures 11 to 14 Based on this, the second relief portion 14 is configured as a relief groove, with the depth of the second relief portion 14 increasing from its middle position to either end. In other words, the depth is greatest at the opposite ends of the second relief portion 14. Thus, the opposite ends of the second relief portion 14 effectively interrupt and isolate the arc. Furthermore, the depth of the middle portion of the second relief portion 14 is minimal, specifically, it can be flush with the surface of the movable spring 12. Thus, the arc-interrupting and arc-isolating effects of the middle portion of the second relief portion 14 are less pronounced, but due to the larger current-carrying cross-sectional area, it does not affect current carrying, that is, it does not affect temperature rise.

[0112] For example, similar to the first avoidance portion 13, the second avoidance portion 14 includes but is not limited to being set as an avoidance groove, an avoidance hole or an avoidance gap, etc., and can be flexibly adjusted and set according to actual needs.

[0113] Based on any of the aforementioned embodiments, the contour shape of the second avoiding portion 14 includes but is not limited to regular shapes such as arc, rectangle, trapezoid, triangle, circle, semicircle, U-shape or Ω-shape, and other various irregular shapes.

[0114] See also Figure 11 、 Figure 12 、 Figure 23 and Figure 25 For example, at least one of the first contact portion 111 and the second contact portion 121 is provided with a third avoidance portion 15 for avoiding each other. The third avoidance portion 15 is located on the side of the first avoidance portion 13 away from the magnetic field direction of the first permanent magnet 30. In this way, on the one hand, the arc can be disconnected, thereby playing the role of arc isolation and rapid arc extinguishing, reducing the arc burning time; on the other hand, since the second avoidance portion 14 is further provided, the contact area between the first contact portion 111 and the second contact portion 121 is further reduced, and the position of the arc starting point is more controlled, and the arc can be controlled to start at a certain point, so that the arc isolation effect is obvious; in addition, it can effectively prevent the arc from flowing toward the inner part of the second contact portion 121, even under high load conditions, it can still ensure product performance and reduce the probability of product failure.

[0115] For example, the opposite ends of the third relief portion 15 on the first contact portion 111 extend to opposite sides of the first contact portion 111 in the width direction; and / or the opposite ends of the third relief portion 15 on the second contact portion 121 extend to opposite sides of the second contact portion 121 in the width direction. In this way, the third relief portion 15 is longer, the arc-breaking and arc-isolating area is larger, and the arc-breaking and arc-isolating effects are improved.

[0116] When both the first contact portion 111 and the second contact portion 121 are provided with the first avoidance portion 13, the first avoidance portion 13 on the first contact portion 111 and the first avoidance portion 13 on the second contact portion 121 are, for example, offset from each other so as to avoid each other, thereby achieving a better arc breaking and arc isolation effect. Of course, the first avoidance portion 13 on the first contact portion 111 and the first avoidance portion 13 on the second contact portion 121 can also be arranged in alignment with each other and in communication.

[0117] Similarly, when both the first contact portion 111 and the second contact portion 121 are provided with a third avoidance portion 15, the third avoidance portion 15 on the first contact portion 111 and the third avoidance portion 15 on the second contact portion 121 can be offset from each other, thereby avoiding each other and achieving a better arc interruption and arc isolation effect. Of course, the third avoidance portion 15 on the first contact portion 111 and the third avoidance portion 15 on the second contact portion 121 can also be arranged in an aligned and connected manner.

[0118] For example, similar to the first avoidance portion 13 , the third avoidance portion 15 includes but is not limited to being set as an avoidance groove, an avoidance hole, or an avoidance gap.

[0119] Based on any of the aforementioned embodiments, the contour shape of the second avoiding portion 14 includes but is not limited to regular shapes such as arc, rectangle, trapezoid, triangle, circle, semicircle, U-shape or Ω-shape, and other various irregular shapes.

[0120] Based on the above embodiment, the third avoidance portion 15 is specifically located between the first avoidance portion 13 and the second avoidance portion 14. The number of third avoidance portions 15 can be flexibly adjusted and set according to actual needs, including but not limited to one or more. For example, "more" means two, three, or other numbers.

[0121] Optionally, the third avoidance portion 15 may be interconnected with the first avoidance portion 13 , or may be independently provided with respect to each other, which is not limited here.

[0122] See also Figure 1 or Figure 2 In one embodiment, two static contact terminals 11 are provided, and one movable spring 12 is provided. A second contact portion 121 is provided at each of the two opposite ends of the movable spring 12 along its length. Two groups of first permanent magnets 30 are provided, and the two groups of first permanent magnets 30 are respectively arranged on the outer sides of the opposite ends of the movable spring 12 along its length.

[0123] See also Figure 2 For example, the relay further includes a second permanent magnet 40. The second permanent magnet 40 is arranged corresponding to the contact unit, and the second permanent magnet 40 is located on the side of the contact unit facing away from the first permanent magnet 30. Optionally, the polarized side of the second permanent magnet 40 faces the corresponding contact unit. The polarity of the side of the second permanent magnet 40 facing the contact unit is opposite to the polarity of the side of the first permanent magnet 30 facing the contact unit. In this way, arc extinguishing is achieved by utilizing the magnetic field formed at the contact unit by the first permanent magnet 30 and the second permanent magnet 40. The magnetic field strength is relatively large, thereby achieving a better arc extinguishing effect.

[0124] Please refer to Figure 2 The second permanent magnet 40 is disposed between the two static contact lead-out terminals 11 , and the second permanent magnet 40 and the first permanent magnet 30 have opposite magnetic properties on two surfaces relative to each other.

[0125] The second permanent magnet 40 can be one, two, or another number. In this embodiment, the second permanent magnet 40 is, for example, two, and the two second permanent magnets 40 are arranged in a one-to-one correspondence with the two first permanent magnets 30 .

[0126] Optionally, when the polarity of the side of the first permanent magnet 30 facing the second permanent magnet 40 is N level, the polarity of the side of the second permanent magnet 40 facing the first permanent magnet 30 is correspondingly S level; conversely, when the polarity of the side of the first permanent magnet 30 facing the second permanent magnet 40 is S level, the polarity of the side of the second permanent magnet 40 facing the first permanent magnet 30 is correspondingly N level.

[0127] For example, in a set of first permanent magnets 30 corresponding to the contact unit, the number of first permanent magnets 30 includes, but is not limited to, one, two, three, or more. The specific number can be flexibly adjusted and set according to actual needs. When the load is low, one first permanent magnet 30 is sufficient; when the load is high, the number of first permanent magnets 30 may be increased, for example, by using two first permanent magnets 30 stacked together to increase the magnetic induction intensity.

[0128] For example, the magnetic force of the first permanent magnet 30 is stronger than the magnetic force of the second permanent magnet 40 .

[0129] To accommodate loads of varying sizes, the number of first permanent magnets 30 can be adjusted, and magnetic materials with varying magnetic strengths can be selected to design the first permanent magnets 30 based on the actual load requirements. Specifically, when the load is low, the first permanent magnets 30 are made of magnetic materials with weaker magnetic strengths; when the load is high, the first permanent magnets 30 are made of magnetic materials with stronger magnetic strengths, thereby increasing the magnetic induction strength.

[0130] It should be noted that the arrangement position, number, shape and arrangement of the first avoidance portion 13 and the third avoidance portion 15 on the movable spring 12 can be specifically referred to, for example, Figures 8 to 32 , can be copied to the first contact portion 111 of the static contact lead-out terminal 11; in other words, the arrangement position, number, shape and arrangement of the first avoidance portion 13 and the third avoidance portion 15 on the first contact portion 111 of the static contact lead-out terminal 11 can be similar to the arrangement position, number, shape and arrangement on the dynamic spring piece 12, and this application will not go into details here, and no additional information will be provided. Figure 1 In addition, the technical effects that the first avoidance portion 13 and the third avoidance portion 15 can bring about on the first contact portion 111 of the static contact lead-out terminal 11 refer to the technical effects that can be embodied on the second contact portion 121 and are not repeated here.

[0131] See also Figure 42In some embodiments, the relay further includes an inner cavity 50 and a base 60. The inner cavity 50 and the base 60 are connected and enclose a chamber. The inner cavity 50 may be made of, but is not limited to, plastic. An electrostatic lead is mounted on the top wall of the inner cavity 50 and extends into the chamber. A movable spring 12 is movably disposed within the chamber. A push assembly 20 is connected to the base 60, and a push rod 22 of the push assembly 20 extends into the chamber and connects to the movable spring 12. A first permanent magnet 30 is mounted within the inner cavity 50 wall, and a second permanent magnet 40 is connected to the inner cavity 50 wall. In this way, the inner cavity 50 wall encases the first permanent magnet 30 and the second permanent magnet 40, effectively protecting them from arc contact and demagnetization defects. The relay further includes a housing (not shown in the figure), which is mounted outside the inner cavity 50 and connected to the base 60. A potting compound may be provided between the outer shell and the inner cavity 50 .

[0132] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0133] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0134] In this application, unless otherwise expressly specified or limited, if a first feature is described as being "above" or "below" a second feature, or similar descriptions, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0135] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0136] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0137] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A relay, characterized in that: include: A contact assembly, the contact assembly comprising a stationary contact lead-out terminal and a movable spring, the stationary contact lead-out terminal being provided with a first contact portion, the movable spring being provided with a second contact portion corresponding in position to the first contact portion; at least one of the first contact portion and the second contact portion being provided with a first avoidance portion for avoiding the other; and A first permanent magnet is disposed around the movable spring.

2. The relay according to claim 1, wherein: The first avoidance portion includes one or more combinations of avoidance grooves, avoidance holes and avoidance gaps.

3. The relay according to claim 2, characterized in that The avoidance groove is a blind groove or a through groove.

4. The relay according to claim 2, characterized in that The avoidance groove is a groove body with closed sides; or the avoidance groove is a groove body with non-closed sides.

5. The relay according to claim 1, wherein: The outline shape of the first avoiding portion is rectangular, trapezoidal, triangular, circular, semicircular, U-shaped or Ω-shaped.

6. The relay according to claim 1, wherein: The first avoidance portion is provided at an outer portion of the first contact portion; and / or the first avoidance portion is provided at an outer portion of the second contact portion.

7. The relay according to claim 6, characterized in that There are multiple first avoidance portions at the outer portion of the first contact portion, and the multiple first avoidance portions are arranged in sequence along the width direction of the first contact portion; and / or there are multiple first avoidance portions at the outer portion of the second contact portion, and the multiple first avoidance portions are arranged in sequence along the width direction of the second contact portion.

8. The relay according to claim 6, characterized in that The first avoidance portion is provided as one on the outer side of the first contact portion, and the first avoidance portion is provided at the middle portion or any one end of the first contact portion in the width direction of the movable spring piece; and / or the first avoidance portion is provided as one on the outer side of the second contact portion, and the first avoidance portion is provided at the middle portion or any one end of the second contact portion in the width direction of the movable spring piece.

9. The relay according to claim 1, wherein: The movable spring piece is provided with a second avoidance portion, and the second avoidance portion is arranged on one side of the second contact portion close to the central axis of the movable spring piece.

10. The relay according to claim 9, characterized in that The opposite ends of the second avoidance portion extend to two opposite sides of the movable spring along the width direction of the movable spring.

11. The relay according to claim 10, characterized in that The second avoidance portion is configured as an avoidance groove, and the depth of the second avoidance portion increases from a middle position to a position at either end thereof.

12. The relay according to claim 9, characterized in that The second avoidance portion is configured as an avoidance groove, an avoidance hole or an avoidance notch; the contour shape of the second avoidance portion is arc, rectangle, trapezoid, triangle, circle, semicircle, U-shape or Ω-shape.

13. The relay according to claim 1, wherein: At least one of the first contact portion and the second contact portion is provided with a third avoidance portion for avoiding each other, and the third avoidance portion is located on a side of the first avoidance portion away from the magnetic field direction of the first permanent magnet.

14. The relay according to claim 13, characterized in that The opposite ends of the third avoidance portion on the first contact portion extend to two opposite sides in the width direction of the first contact portion respectively; and / or the opposite ends of the third avoidance portion on the second contact portion extend to two opposite sides in the width direction of the second contact portion respectively.

15. The relay according to claim 13, wherein: The third avoidance portion is configured as an avoidance groove, an avoidance hole or an avoidance gap; the contour shape of the third avoidance portion is arc, rectangle, trapezoid, triangle, circle, semicircle, U-shape or Ω-shape.

16. The relay according to claim 1, wherein: There are two static contact lead-out terminals, one movable spring, and a second contact portion is provided at each of the opposite ends of the movable spring along the length direction; there are two groups of first permanent magnets, and the two groups of first permanent magnets are respectively arranged on the outer sides of the opposite ends of the movable spring along the length direction, and the two groups of first permanent magnets are respectively arranged in a one-to-one correspondence with the two second contact portions.

17. The relay according to claim 16, characterized in that The relay further includes a second permanent magnet, which is disposed between the two static contact lead-out terminals. The second permanent magnet and the first permanent magnet have opposite magnetic properties on two surfaces facing each other.

18. The relay according to claim 17, wherein: The number of the first permanent magnets is adjustable; and / or the magnetic force of the first permanent magnets is stronger than the magnetic force of the second permanent magnets.

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