A trip unit, an electromagnetic trip unit, and an electrical protection device

Abstract

The application discloses a tripping assembly, wherein a permanent magnet assembly is arranged in a U-shaped cavity of a magnetic yoke, the overall volume of the tripping assembly is reduced, the permanent magnet and a magnetic conducting sheet are respectively connected to a horizontal arm and a second vertical arm of the magnetic yoke, the magnetic resistance of the permanent magnet magnetic circuit is minimized and stabilized, meanwhile, the magnetic flux generated by the permanent magnet is divided into two magnetic flux branches with different sizes, and the magnetic flux branch with smaller magnetic flux is used to provide magnetic force for an armature, the tripping assembly has stable magnetic flux and long service life, and can meet the working conditions of small current and low power consumption. The application further discloses an electromagnetic tripping device provided with the tripping assembly, and an electrical protection device provided with the electromagnetic tripping device.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic tripping devices, and more particularly to a tripping assembly, an electromagnetic tripping device, and electrical protection equipment. Background Technology

[0002] In existing electromagnetic trip device technology, one polar face of the magnet is directly below the armature, and the magnetic flux generated by the magnet acts directly on the armature through this polar face. In this type of solution, a certain gap is often required between the polar face of the magnet and the armature, as shown in Chinese Patent No. CN1763884B. However, this technology has the following problems: Due to unavoidable assembly errors during the assembly process, the gap between the blade plate (i.e., the armature) and the magnet in actual use of this electromagnetic trip device will deviate from the designed gap; in addition, after tripping, the blade plate is reset by pushing it against the reset pin. When the reset force applied by the reset pin to the blade plate is too large, or after multiple resets, the blade plate will deform and warp, causing the gap between the blade plate and the magnet to change; if the gap between the blade plate and the magnet is uncontrollable, the attraction force of the magnet on the blade plate will not be constant. Under the same current applied to the coil, the electromagnetic trip device may trip or may not trip, resulting in unstable operation of the electromagnetic trip device, which will seriously affect its use.

[0003] Although there are some design schemes that prevent the polar face of the magnet from directly acting on the armature, such as Chinese patents with announcement number CN203386689U and CN108281332A.

[0004] In the Chinese patent CN203386689U, the magnet is located outside the yoke, resulting in an excessively large overall volume. Furthermore, the two magnetic fluxes generated by the magnet are almost entirely applied to the magnet through the support component, making it unsuitable for low-current, low-power applications. Additionally, the magnetic flux is affected by the cross-sectional size of the support component.

[0005] In the Chinese patent CN108281332A, although the magnet is located inside the yoke, its structure is relatively complex, and the magnetic flux generated by the magnet is almost entirely applied to the magnet, which is also not suitable for low current and low power consumption conditions.

[0006] Therefore, it is necessary to design a new electromagnetic trip unit that is suitable for low current, low power consumption, and stable operation. Summary of the Invention

[0007] In order to overcome at least one of the defects described in the prior art, the present invention provides a tripping component, an electromagnetic trip unit, and an electrical protection device, thereby solving the problem of unstable use of existing electromagnetic trip units, and enabling application in low-current, low-power conditions, with strong overall performance.

[0008] The technical solution adopted by this invention to solve its problem is:

[0009] A tripping assembly, comprising:

[0010] The magnetic yoke is U-shaped and includes a first vertical arm, a second vertical arm, and a horizontal arm. The first and second vertical arms are arranged in parallel, and the horizontal arm connects the first and second vertical arms. Both the first and second vertical arms have abutting surfaces.

[0011] The armature, which is movable relative to the yoke, can come into contact with the two abutting surfaces to form a closed magnetic circuit;

[0012] The reset elastic element is connected to the armature and provides elastic force for the armature to disengage from the contact surface;

[0013] The permanent magnet assembly is located in the U-shaped cavity of the yoke. The permanent magnet assembly includes a permanent magnet and a magnetic sheet connected in phase. One of the permanent magnet and the magnetic sheet is connected to a horizontal arm, and the other is connected to a second vertical arm. The permanent magnet, the first part of the second vertical arm, the first part of the horizontal arm, and the magnetic sheet constitute a first permanent magnet flux shunt. The permanent magnet, the second part of the second vertical arm, the armature, the first vertical arm, the second part of the horizontal arm, and the magnetic sheet constitute a second permanent magnet flux shunt. The flux of the first permanent magnet flux shunt is greater than the flux of the second permanent magnet flux shunt. The second permanent magnet flux shunt provides magnetic force for the armature to maintain contact with the two abutting surfaces.

[0014] Furthermore, an excitation coil is provided on the first vertical arm, and the armature is rotatably connected to the second vertical arm, with the armature being movable relative to the yoke along the normal direction of the contact surface.

[0015] Furthermore, the magnetic conductive sheet is fixedly connected to the horizontal arm, one end of the permanent magnet abuts against the second vertical arm, and the other end of the permanent magnet abuts against the magnetic conductive sheet.

[0016] Furthermore, a magnetic shielding sheet is provided between the permanent magnet and the magnetic conductive sheet, and / or a magnetic shielding sheet is provided between the permanent magnet and the second vertical arm.

[0017] Furthermore, the second vertical arm is equipped with a fixing device for mounting permanent magnets.

[0018] Furthermore, a support is fixedly connected to the second vertical arm, and the fixing device includes two clamping plates fixedly connected to the support and arranged opposite to each other. One end of the permanent magnet is inserted into the mounting cavity formed by the two clamping plates and abuts against the second vertical arm. The clamping plates are provided with claws for limiting the permanent magnet.

[0019] Furthermore, the support is installed on the outside of the second vertical arm and is rotatably connected to the armature and to the reset elastic element; the two clamping plates are bent from opposite sides of the support toward the first vertical arm and clamped on both sides of the second vertical arm in the width direction.

[0020] Furthermore, the end of the magnetic sheet away from the horizontal arm is close to the armature and maintains a gap. The permanent magnet, the second part of the second vertical arm, a part of the armature, and a part of the magnetic sheet constitute the third permanent magnet flux shunt, and the flux of the first permanent magnet flux shunt is greater than the flux of the third permanent magnet flux shunt.

[0021] Based on the same inventive concept, a second objective of the present invention is to provide an electromagnetic trip device, which includes the tripping components described above.

[0022] Furthermore, the electromagnetic trip unit also includes an upper housing, a lower housing, and a protective cover. The upper housing and the lower housing are interlocked and used to install the trip assembly. The protective cover is fitted over the outside of the upper housing and the lower housing, and the installation direction of the protective cover is perpendicular to the arrangement direction of the upper housing and the lower housing. The upper housing is provided with a connecting boss and a reset post for connecting with the armature. The connecting boss is provided with a reset hole for the reset post to pass through. The protective cover is provided with a limiting groove that opens along its installation direction and is limited and matched with the connecting boss.

[0023] Based on the same inventive concept, a third objective of this invention is to provide an electrical protection device that includes the aforementioned electromagnetic trip unit.

[0024] In summary, the tripping assembly, electromagnetic trip unit, and electrical protection device provided by this invention have the following technical effects:

[0025] (1) The permanent magnet assembly is located in the U-shaped cavity of the yoke, which reduces the overall volume of the tripping assembly. The permanent magnet and the magnetic conductive sheet are connected to the horizontal arm and the second vertical arm of the yoke respectively, so that the magnetic resistance of the permanent magnet flux circuit is minimized and stabilized. At the same time, the magnetic flux generated by the permanent magnet is divided into two magnetic flux branches of different magnitudes, and the magnetic flux branch with smaller magnetic flux is used to provide magnetic force for the armature. The tripping assembly has stable magnetic flux, long service life, and can meet the working conditions of low current and low power consumption.

[0026] (2) A magnetic shielding sheet is installed in the permanent magnet flux shunt. The magnetic shielding sheet prevents the flux in the permanent magnet flux shunt from becoming unstable due to component and assembly errors.

[0027] (3) The position of the permanent magnet can be fixed by the fixing device on the second vertical arm, which can further improve the stability of the magnetic flux.

[0028] (4) The fixing device is combined with the support, which reduces the number of parts, and the structure is simple and easy to assemble. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the electromagnetic trip unit according to Embodiment 1 of the present invention;

[0030] Figure 2This is an exploded view of the electromagnetic trip device according to Embodiment 1 of the present invention;

[0031] Figure 3 This is a schematic diagram of the tripping assembly and reset post according to Embodiment 1 of the present invention;

[0032] Figure 4 This is an exploded view of the tripping assembly of Embodiment 1 of the present invention;

[0033] Figure 5 This is a schematic diagram of the support structure of Embodiment 1 of the present invention;

[0034] Figure 6 This is a schematic diagram of the principle of the three magnetic circuits in Embodiment 1 of the present invention;

[0035] Figure 7 This is a schematic diagram of the tripping assembly and reset post according to Embodiment 2 of the present invention;

[0036] Figure 8 This is a schematic diagram of the principle of the four magnetic circuits in Embodiment 2 of the present invention.

[0037] The meanings of the reference numerals in the attached figures are as follows:

[0038] 1. Tripping assembly; 11. Magnetic yoke; 111. First vertical arm; 112. Second vertical arm; 113. Horizontal arm; 114. Pin; 12. Armature; 13. Reset elastic element; 14. Permanent magnet assembly; 141. Permanent magnet; 142. Magnetic conductive sheet; 143. Magnetic shielding sheet; 15. Excitation coil; 16. Buffer spring; 17. Support; 171. First hook; 172. Pin hole; 173. Clamping piece; 174. Claw; 175. Mounting cavity; 18. Connector; 181. Second hook; 2. Upper housing; 21. Connecting boss; 22. Reset post; 23. Reset hole; 3. Lower housing; 4. Protective cover; 41. Limiting groove. Detailed Implementation

[0039] To better understand and implement this invention, the technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings.

[0040] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0042] Example 1

[0043] See Figure 1 and Figure 2 The present invention discloses an electromagnetic trip device, including a trip assembly 1, an upper housing 2, a lower housing 3, and a protective cover 4. The trip assembly 1 is installed in the cavity formed after the upper housing 2 and the lower housing 3 are fastened together, and the protective cover 4 is sleeved on the outside of the upper housing 2 and the lower housing 3 to provide protection.

[0044] Preferably, in order to better protect and prevent the upper housing 2 and the lower housing 3 from loosening, the installation direction of the protective cover 4 is perpendicular to the arrangement direction of the upper housing 2 and the lower housing 3.

[0045] More preferably, the upper housing 2 is provided with a connecting boss 21 and a reset post 22 for connecting with the armature 12. The connecting boss 21 is provided with a reset hole 23 for the reset post 22 to pass through. The protective cover 4 is provided with a limiting groove 41 that opens along its installation direction and is limited and matched with the connecting boss 21, so that after the protective cover 4 is fitted onto the upper housing 2 and the lower housing 3, the cooperation between the limiting groove 41 and the connecting boss 21 prevents the protective cover 4 from accidentally falling off.

[0046] See Figure 2 , Figure 3 and Figure 4 In this embodiment, the tripping assembly 1 includes a U-shaped magnetic yoke 11, an armature 12, a permanent magnet assembly 14, a reset elastic element 13, and an excitation coil 15. The magnetic yoke 11 includes a first vertical arm 111 and a second vertical arm 112 arranged in parallel, and a horizontal arm 113 connecting the first vertical arm 111 and the second vertical arm 112. Both vertical arms 111 and 112 of the magnetic yoke 11 have abutting surfaces. The excitation coil 15 is disposed on the first vertical arm 111 of the magnetic yoke 11. The permanent magnet assembly 14 is located in the U-shaped cavity of the magnetic yoke 11 and is specifically connected between the second vertical arm 112 and the horizontal arm 113. This avoids interference between components and makes full use of space. The tripping assembly 1 has a compact structure and a small overall size.

[0047] The armature 12 is movably positioned relative to the yoke 11, and can be attached to the two contact surfaces to form a closed magnetic circuit.

[0048] The reset elastic element 13 is connected to the armature 12, and the reset elastic element 13 provides elastic force for the armature 12 to disengage from the two abutting surfaces.

[0049] In this embodiment, the reset elastic element 13 is a spring. In other embodiments, it can also be a torsion spring, a rubber band, or other elastic material.

[0050] The permanent magnet assembly 14 provides magnetic force to keep the armature 12 in contact with the two abutting surfaces.

[0051] Importantly, the permanent magnet assembly 14 includes a permanent magnet 141 and a magnetic sheet 142 connected in phase. Specifically, the magnetic sheet is fixedly connected to the horizontal arm 113, one end of the permanent magnet 141 abuts against the magnetic sheet 142, and the other end of the permanent magnet 141 abuts against the second vertical arm 112.

[0052] Combination Figure 6 The above scheme can form the following three magnetic circuits:

[0053] The first permanent magnet flux branch S1 consists of a permanent magnet 141, the first part of the second vertical arm 112, the first part of the horizontal arm 113, and a magnetic sheet 142. Regardless of whether the armature 12 is in contact with the two contact surfaces, most of the permanent magnet flux generated by the permanent magnet 141 starts from the permanent magnet 141, passes through the first part of the second vertical arm 112, the first part of the horizontal arm 113, and the magnetic sheet 142 in sequence, and then returns to the permanent magnet 141. In the first permanent magnet flux branch S1, there is no air gap, the path is short, the magnetic resistance is minimal, and the magnetic efficiency is the highest. Therefore, most of the permanent magnet flux generated by the permanent magnet 141 can pass through.

[0054] The second permanent magnet flux branch S2 is composed of a permanent magnet 141, the second part of the second vertical arm 112, an armature 12, the first vertical arm 111, the second part of the horizontal arm 113, and a magnetic conductive sheet 142. When the armature 12 is in contact with the two contact surfaces, a small portion of the permanent magnet flux generated by the permanent magnet 141 starts from the permanent magnet 141, passes through the second part of the second vertical arm 112, the armature 12, the first vertical arm 111, the second part of the horizontal arm 113, and the magnetic conductive sheet 142 in sequence, and then returns to the permanent magnet 141. In the second permanent magnet flux branch S2, there is only an air gap on the surface where the armature 12 contacts the yoke 11, and its path through the first permanent magnet flux branch S1 is long, with low magnetic resistance and is not affected by the deformation of the armature 12, resulting in high magnetic efficiency. Therefore, a small portion of the permanent magnet flux generated by the permanent magnet 141 can pass through.

[0055] Electromagnetic path S3: Composed of armature 12 and yoke 11. When armature 12 is in contact with the two contact surfaces, excitation coil 15 is energized. Electromagnetic flux starts from the first vertical arm 111, passes through armature 12, second vertical arm 112 and horizontal arm 113 in sequence, and then returns to the first vertical arm 111.

[0056] In the three magnetic circuits mentioned above, the first permanent magnet flux branch S1 and the second permanent magnet flux branch S2 are in the same direction, while the second permanent magnet flux branch S2 and the electromagnetic path S3 are in opposite directions. The first permanent magnet flux branch S1 does not pass through the armature 12, while only the second permanent magnet flux branch S2 and the electromagnetic path S3 pass through the armature 12. Therefore, the second permanent magnet flux branch S2 provides magnetic force to keep the armature 12 in contact with the two abutting surfaces, and the electromagnetic path S3 provides magnetic force to separate the armature 12 from the two abutting surfaces.

[0057] It is understandable that in the three magnetic circuits mentioned above, the magnetic flux can also flow in the opposite direction as a whole, which can achieve the same purpose and effect.

[0058] It is understandable that the positions of the permanent magnet 141 and the magnetic conductive sheet 142 can be interchanged, that is, the permanent magnet 141 abuts against the horizontal arm 113 and the magnetic conductive sheet 142 is fixedly connected to the second vertical arm 112, which can also achieve the above purpose and effect.

[0059] When there is no electromagnetic flux, the armature 12 relies on the second permanent magnet flux branch S2 to form a closed state between the armature 12 and the yoke 11. When leakage occurs, the excitation coil 15 will receive the CT signal and generate electromagnetic flux, which will break the balance between the flux of the second permanent magnet flux branch S2 and the reset elastic element 13 through the electromagnetic path S3. At this time, the armature 12 will open and the tripping action will occur.

[0060] By combining the above schemes, the permanent magnet assembly 14 is located in the U-shaped cavity of the yoke 11, reducing the overall volume of the tripping assembly 1. The permanent magnet 141 and the magnetic conductive sheet 142 are respectively connected to the horizontal arm 113 and the second vertical arm 112 of the yoke 11, minimizing and stabilizing the magnetic resistance of the permanent magnet flux circuit. At the same time, the magnetic flux generated by the permanent magnet 141 is divided into two magnetic flux branches of different magnitudes, and the magnetic flux branch with smaller magnetic flux is used to provide magnetic force for the armature 12. The tripping assembly 1 has stable magnetic flux, long service life, and can meet the working conditions of low current and low power consumption.

[0061] See Figure 3 and Figure 4 Preferably, in this embodiment, the armature 12 is rotatably connected to the second vertical arm 112, and the armature 12 is movable relative to the magnetic yoke 11 along the normal direction of the abutment surface, thereby increasing the tightness of the abutment surface between the armature 12 and the second vertical arm 112 and reducing the possibility of magnetic leakage.

[0062] More preferably, in this embodiment, a non-magnetic support 17 is fixedly provided on the second vertical arm 112. Specifically, the support 17 is provided with a pin hole 172, and a pin 114 is provided on the outer side wall of the second vertical arm 112. The support 17 is installed on the outer side of the second vertical arm 112 by the interference fit between the pin hole 172 and the pin 114. Of course, the connection between the support 17 and the second vertical arm 112 can also be achieved by pasting, welding, or fastening. The armature 12 is rotatably connected to the support 17, and the armature 12 rotates around the support 17. The rotating shaft is slidably connected to the support 17. The rotating shaft slides relative to the support 17 along the normal direction of the abutting surface, so that the armature 12 can both rotate relative to the magnetic yoke 11 and move relative to the magnetic yoke 11 along the normal direction of the abutting surface. When the trip is triggered, the armature 12 swings relative to the support 17 under the pull of the reset elastic element 13, and the trip is quick. In the normal state when the trip is not triggered, since the armature 12 can slide relative to the support 17, the fit between the armature 12 and the abutting surface is better, reducing the possibility of magnetic leakage.

[0063] See Figure 4 In this embodiment, a non-magnetic connector 18 is fixed on the armature 12. The connector 18 abuts against the support 17 and can rotate relative to it, thereby enabling the armature 12 to rotate relative to the support 17, reducing the processing difficulty of each component and reducing the wear of the armature 12, which would affect its service life.

[0064] Combination Figure 5 Specifically, one end of the reset elastic member 13 is connected to the support 17 and the other end is connected to the connector 18, thereby indirectly providing elasticity to the armature 12. Specifically, the support 17 is provided with a first hook 171 and the connector 18 is provided with a second hook 181. The two ends of the reset elastic member 13 are respectively hooked onto the first hook 171 and the second hook 181.

[0065] Specifically, in this embodiment, a buffer spring 16 is also provided on the armature 12, and the buffer spring 16 is located on the side of the armature 12 away from the contact surface; the buffer spring 16 buffers the restoring force applied to the armature 12 by the reset post 22, reducing the deformation of the armature 12. Preferably, the buffer spring 16 is made of a non-magnetic material; in addition, the buffer spring 16 can also be integrally formed with the connector 18, which is beneficial for saving materials and is more economical.

[0066] See Figure 3 and Figure 4 A magnetic shielding sheet 143 is provided between the permanent magnet 141 and the magnetic conductive sheet 142, and / or a magnetic shielding sheet 143 is provided between the permanent magnet 141 and the second vertical arm 112. The magnetic shielding sheet 143 is provided in the permanent magnet flux branches S1 and S2. The magnetic shielding sheet 143 prevents the magnetic flux in the permanent magnet flux branches S1 and S2 from becoming unstable due to component and assembly errors.

[0067] See Figure 3 and Figure 4 In particular, in this embodiment, a fixing device is provided on the second vertical arm 112. The fixing device is used to install the permanent magnet 141 to fix the position of the permanent magnet 141 and ensure the stability of the magnetic flux in the magnetic circuit.

[0068] Specifically, the fixing device includes two clamping pieces 173 that are fixedly connected to the support 17 and arranged opposite each other. The two clamping pieces 173 form a mounting cavity 175. One end of the permanent magnet 141 is inserted into the mounting cavity 175 and abuts against the second vertical arm 112.

[0069] Preferably, the clamping plate 173 is provided with a claw 174 for limiting the permanent magnet 141, which can effectively prevent the permanent magnet 141 from loosening and detaching. The claw 174 is specifically located at the free end of the clamping plate 173.

[0070] More preferably, the two clamping pieces 173 are bent from opposite sides of the support 17 toward the first vertical arm 111, and the two clamping pieces 173 are clamped on both sides of the second vertical arm 112 in the width direction to avoid relative rotation between the support 17 and the second vertical arm 112.

[0071] By combining the above solutions, the functions of connecting the armature 12, connecting the reset elastic element 13, and fixing the permanent magnet 141 are all integrated into the support 17, which greatly reduces the number of parts, and the structure is simple and easy to assemble.

[0072] When assembling the tripping assembly 1 of this scheme, the support 17 can be installed on the second vertical arm 112 first, then the permanent magnet 141 can be installed on the support 17, the magnetic shielding sheet 143 can be installed at the end of the permanent magnet 141, the magnetic conductive sheet can be welded on the horizontal arm 113, and finally the excitation coil 15, armature 12, reset elastic element 13 and other components can be assembled.

[0073] Example 2

[0074] See Figure 7 and Figure 8 The only difference between this embodiment and embodiment 1 is that the magnetic conductive sheet 14 in this embodiment is longer. Specifically, the end of the magnetic conductive sheet 14 away from the horizontal arm 13 is close to the armature 12 and maintains a gap. The permanent magnet 141, the second part of the second vertical arm 112, a part of the armature 12 and a part of the magnetic conductive sheet 142 constitute the third permanent magnet flux branch S4, and the flux of the first permanent magnet flux branch S1 is greater than the flux of the third permanent magnet flux branch S4.

[0075] Understandably, with Figure 8The direction shown is for reference. Since there is a gap between the upper end of the magnetic sheet 14 and the lower surface of the armature 12 (which can be understood as an air gap or magnetic gap), its magnetic resistance is large and its magnetic efficiency is low. Therefore, it can ensure that the magnetic flux of the first permanent magnet flux branch S1 is greater than the magnetic flux of the third permanent magnet flux branch S4.

[0076] Since the magnetic flux of the first permanent magnet flux branch S1 and the magnetic flux of the electromagnetic path S3 both pass through the second vertical arm 112 and the horizontal arm 113, and the saturation magnetic induction intensity of the material is limited, when the magnetic flux of the first permanent magnet flux branch S1 is large, it will occupy all or most of the magnetic channel formed by the second vertical arm 112 and the horizontal arm 113. This makes it difficult for the magnetic flux generated by the electromagnetic path S3 to enter the second vertical arm 112 and the horizontal arm 113, thus rendering the magnetic force provided by the electromagnetic path S3 for the armature 12 to disengage from the two contact surfaces ineffective. Therefore, through the action of the third permanent magnet flux branch S4, the magnetic flux generated by the permanent magnet 141 can be shared, preventing the electromagnetic path S3 from malfunctioning due to the large magnetic flux of the first permanent magnet flux branch S1.

[0077] The other technical features of this embodiment are the same as those of Embodiment 1, and the technical problems solved and the technical effects achieved are also the same, so they will not be repeated here.

[0078] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications are also considered within the scope of protection of this invention.

Claims

1. A trip unit, comprising: The application relates to a magnetic latching assembly, comprising: a U-shaped yoke, which comprises a first vertical arm, a second vertical arm and a horizontal arm, the first vertical arm and the second vertical arm are arranged in parallel, and the horizontal arm is connected between the first vertical arm and the second vertical arm, and the first vertical arm and the second vertical arm each have an abutting surface; an armature, which is movably arranged relative to the yoke and can be in close contact with the two abutting surfaces to form a closed magnetic loop; a reset elastic member, which is connected to the armature and provides elastic force for the armature to be separated from the abutting surfaces; a permanent magnet assembly, which is arranged in a U-shaped cavity of the yoke, and the permanent magnet assembly comprises a permanent magnet and a magnetic conducting sheet which are connected in a magnetic conducting mode, one of the permanent magnet and the magnetic conducting sheet is connected to the horizontal arm, and the other is connected to the second vertical arm, the permanent magnet, a first part of the second vertical arm, a first part of the horizontal arm and the magnetic conducting sheet form a first permanent magnetic flux branch, the permanent magnet, a second part of the second vertical arm, the armature, the first vertical arm, a second part of the horizontal arm and the magnetic conducting sheet form a second permanent magnetic flux branch, the magnetic flux of the first permanent magnetic flux branch is greater than that of the second permanent magnetic flux branch, and the second permanent magnetic flux branch provides magnetic force for the armature to keep in close contact with the two abutting surfaces.

2. The trip unit of claim 1, wherein, The first vertical arm is provided with an exciting coil, the armature is rotatably connected to the second vertical arm, and the armature is movably arranged relative to the yoke along the normal direction of the abutting surfaces.

3. The trip unit of claim 1, wherein, The magnetic conducting sheet is fixedly connected to the horizontal arm, one end of the permanent magnet is in abutment with the second vertical arm, and the other end of the permanent magnet is in abutment with the magnetic conducting sheet.

4. The trip unit of claim 3, wherein, The permanent magnet and the magnetic conducting sheet are provided with a magnetic separation sheet, and / or the permanent magnet and the second vertical arm are provided with a magnetic separation sheet.

5. The trip unit of claim 3, wherein, The second vertical arm is provided with a fixing device for mounting the permanent magnet.

6. The trip unit of claim 5, wherein, The second vertical arm is fixedly connected with a support, the fixing device comprises two clamping sheets which are fixedly connected to the support and oppositely arranged, one end of the permanent magnet is inserted into a mounting cavity surrounded by the two clamping sheets and is in abutment with the second vertical arm, and the clamping sheets are provided with pawls for limiting the permanent magnet.

7. The trip unit of claim 6, wherein, The support is mounted on the outer side of the second vertical arm, the support is rotatably connected with the armature and connected with the reset elastic member, the two clamping sheets are bent and formed from the opposite sides of the support towards the first vertical arm, and the two clamping sheets are clamped on both sides of the second vertical arm in the width direction.

8. The trip unit of any of claims 3 to 7, wherein, One end of the magnetic conducting sheet away from the horizontal arm is close to the armature and keeps a gap, the permanent magnet, the second part of the second vertical arm, a part of the armature and a part of the magnetic conducting sheet form a third permanent magnetic flux branch, and the magnetic flux of the first permanent magnetic flux branch is greater than that of the third permanent magnetic flux branch.

9. An electromagnetic trip unit characterized by, The application further relates to a tripping assembly comprising the magnetic latching assembly according to any one of claims 1 to 8.

10. The electromagnetic trip unit of claim 9, wherein, The upper shell and the lower shell are buckled to each other and used for mounting the tripping assembly, a protective cover is sleeved outside the upper shell and the lower shell, and the mounting direction of the protective cover is perpendicular to the arrangement direction of the upper shell and the lower shell; a connecting boss is arranged on the upper shell, and a reset column for connecting with the armature is arranged on the connecting boss, a reset hole for the reset column to pass through is arranged on the connecting boss, and a limiting groove opening along the mounting direction of the protective cover and limitedly matched with the connecting boss is arranged on the protective cover.

11. Electrical protection device, characterized in that it comprises an electromagnetic release according to claim 9 or 10.

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