electromagnetic mechanism

Abstract

The electromagnetic mechanism comprises a coil, a core arranged in the coil, an outer magnetic yoke and an inner magnetic yoke, the inner magnetic yoke is located between the coil and the outer magnetic yoke, a permanent magnet is arranged on the inner magnetic yoke, the inner magnetic yoke is provided with an inner bending foot which is bent towards the core on the side close to the core, the inner bending foot is provided with an avoiding slot for avoiding the core, a first air gap is formed between the four sides of the core and the inner bending foot, the avoiding slot for avoiding the core is arranged on the inner bending foot of the inner magnetic yoke, the four sides of the core form the first air gap which is in contact with the inner magnetic yoke, the outer side of the inner magnetic yoke forms a new magnetic circuit through the first air gap, and the new magnetic circuit is attracted by the permanent magnet, so that the attraction and release characteristics can be ensured, the gasket is not needed, and the problems of increased assembly difficulty, difficult size control and large assembly error caused by the gasket can be avoided.

Description

Technical Field

[0001] This invention relates to the field of low-voltage electrical appliances, and more specifically to an electromagnetic mechanism. Background Technology

[0002] Electromagnetic mechanisms are widely used as driving components in various control electrical appliances. They typically include a support, moving parts, stationary parts, coils, and elastic elements. The coils can generate electromagnetic force between the moving and stationary parts, driving the moving parts to move against the force of the elastic elements. After the electromagnetic force generated by the coils disappears, the moving parts can move in the opposite direction under the restoring force of the elastic elements.

[0003] When a DC electromagnetic mechanism uses a permanent magnet, in order to reduce magnetic leakage, a shim is usually used to form an air gap between the moving and stationary parts in order to achieve reliable attraction and release characteristics. However, since the shim is usually thin, not only is the shim itself prone to deformation, which increases the assembly difficulty of the electromagnetic mechanism, but the shim also has the problems of difficult size control and large assembly error, which in turn affects the stability of the electromagnetic mechanism. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide an electromagnetic mechanism that does not require the use of shims, has low precision requirements, and has reliable engagement and release characteristics.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] An electromagnetic mechanism includes a coil, an iron core disposed within the coil, an outer magnetic yoke, and an inner magnetic yoke. The inner magnetic yoke is located between the coil and the outer magnetic yoke. A permanent magnet is disposed on the inner magnetic yoke. The inner magnetic yoke has an inwardly bent foot on its side near the iron core, which bends towards the iron core. The inwardly bent foot has a clearance groove for avoiding the iron core. A first air gap is formed between the iron core and the inwardly bent foot.

[0007] Preferably, the iron core is provided with a bushing around its perimeter, the distance 'a' from the sidewall of the clearance groove to the iron core is greater than the thickness of the bushing, and the bushing extends into the first air gap and is spaced apart from the sidewall of the clearance groove.

[0008] Preferably, the outer magnetic yoke has an outer bent leg that bends towards the iron core. The outer bent leg is arranged opposite to the inner bent leg. An armature connected to the iron core is provided between the outer bent leg and the inner bent leg in the axial direction of the iron core. The distance D1 from the inner bent leg to the outer bent leg of the outer magnetic yoke minus the thickness D2 of the armature is greater than the distance a from the sidewall of the clearance groove to the iron core in the radial direction of the iron core.

[0009] Preferably, the sidewall of the clearance groove is an arc-shaped clearance surface, and the distance from each position on the clearance surface to the corresponding surface of the iron core is equal and is 'a'.

[0010] Preferably, the outer magnetic yoke includes a side plate and an outer bent foot, and the permanent magnet is disposed between the side plate and the inner magnetic yoke. In the axial direction of the iron core, the farthest distance from the armature to the outer bent foot is b, and the farthest distance from the armature to the inner bent foot is c, wherein b = c > a.

[0011] Preferably, the minimum distance from the armature to the side plate along the axial direction of the core is d, where d > b = c; and the length of the contact between one end of the armature and the outer bent foot is less than or equal to 6 mm.

[0012] Preferably, the permanent magnet generates a first electromagnetic path, a second electromagnetic path, and a third electromagnetic path respectively when the coil is energized;

[0013] The first electromagnetic path passes sequentially through the permanent magnet, the outer yoke, the iron core, the first air gap, and the inner yoke before returning to the permanent magnet;

[0014] The second electromagnetic path passes sequentially through the permanent magnet, the outer yoke, the armature, the moving iron core, and the inner yoke before returning to the permanent magnet;

[0015] The third electromagnetic path passes through the outer yoke, the iron core, the armature, and the outer yoke in sequence.

[0016] Preferably, a second magnetic conductor is provided at the end of the iron core away from the first air gap, and a sleeve is provided between the second magnetic conductor and the iron core.

[0017] Preferably, the magnetic field includes two outer yokes and two inner yokes. The two outer yokes are arranged opposite each other, and the two inner yokes are arranged opposite each other between the two outer yokes. The outer yokes include side plates, with upper and outer bent feet respectively provided at both ends of the side plates. The permanent magnet is disposed between the side plates and the inner yokes. The outer and inner bent feet are arranged opposite each other. An armature is disposed between the outer and inner bent feet. One side of the armature is connected to one end of the iron core. The armature has a partition on the side away from the iron core, and a support plate on the side of the partition away from the armature. The support plate, partition, and armature are connected to the iron core by screws or rivets.

[0018] Preferably, the coil is mounted on a coil frame, which includes a cylinder and a base and a cover plate integrally formed at both ends of the cylinder. The iron core is mounted on the inner side of the cylinder, and the coil is mounted on the outer side of the cylinder, located between the base and the cover plate. The base is provided with an inner mounting groove and an outer mounting groove, which are respectively matched with the inner magnetic yoke and the outer magnetic yoke for limiting.

[0019] The electromagnetic mechanism invented in this invention provides a clearance groove on the inner bent foot of the inner magnetic yoke to avoid the iron core, thereby forming a first air gap around the iron core that contacts the inner magnetic yoke. A new magnetic circuit is formed on the outer side of the inner magnetic yoke through the first air gap, and then the new magnetic circuit is attracted by a permanent magnet. This not only ensures the attraction and release characteristics, but also eliminates the need for shims, thus avoiding the problems of increased assembly difficulty, difficulty in controlling dimensions, and large assembly errors caused by shims.

[0020] In addition, the first air gap prevents the main magnetic circuit from going directly from the iron core to the inner yoke, but instead requires it to go through the armature. This causes the permanent magnet to generate an upward attraction on the armature, ensuring the upward force on the iron core and guaranteeing reliable resetting. Attached Figure Description

[0021] Figure 1 This is an exploded view of the electromagnetic mechanism created in this invention;

[0022] Figure 2 This is a schematic diagram of the structure of the inner magnetic yoke 13 created in this invention;

[0023] Figure 3 This is a schematic diagram of the cooperation between the inner magnetic yoke 13 and the iron core 16 created in this invention;

[0024] Figure 4 This is a cross-sectional view of the electromagnetic mechanism created by this invention when it is de-energized;

[0025] Figure 5 This is a cross-sectional view of the electromagnetic mechanism created in this invention when it is energized;

[0026] Figure 6 This is a schematic diagram of the structure of the external magnetic yoke 11 created in this invention;

[0027] Figure 7 This is another structural schematic diagram of the inner magnetic yoke 13 created in this invention;

[0028] Figure 8 This is another cross-sectional view of the electromagnetic mechanism created in this invention;

[0029] Figure 9 This is a schematic diagram of the structure of the coil frame 15 created in this invention;

[0030] Figure 10 This is a cross-sectional view of the coil frame 15 created in this invention. Detailed Implementation

[0031] The specific embodiments of the electromagnetic mechanism created by the present invention are further illustrated below with reference to the accompanying drawings. The electromagnetic mechanism created by the present invention is not limited to the descriptions of the following embodiments.

[0032] like Figure 1-3As shown, the electromagnetic mechanism created by the present invention includes a coil 14, an iron core 16 disposed within the coil 14, an outer magnetic yoke 11, and an inner magnetic yoke 13. The inner magnetic yoke 13 is located between the coil 14 and the outer magnetic yoke 11. A permanent magnet 12 is provided on the inner magnetic yoke 13. The inner magnetic yoke 13 has an inwardly bent foot 131 on its side near the iron core 16, which bends toward the iron core 16. The inwardly bent foot 131 has a clearance groove 132 for avoiding the iron core 16. A first air gap 100 is formed between the iron core 16 and the side wall of the clearance groove 132.

[0033] The electromagnetic mechanism created by this invention provides a clearance groove 132 on the inner bent foot 131 of the inner magnetic yoke 13 to avoid the iron core 16, thereby forming a first air gap 100 between the side walls of the clearance groove 132 around the iron core 16. A new magnetic circuit is formed on the outer side of the inner magnetic yoke 13 through the first air gap 100, and the new magnetic circuit is attracted by the permanent magnet 12. This not only ensures the attraction and release characteristics, but also eliminates the need for shims, thus avoiding the problems of increased assembly difficulty, difficulty in controlling dimensions, and large assembly errors caused by shims.

[0034] like Figure 1-3 As shown, the electromagnetic mechanism of this embodiment includes two outer magnetic yokes 11 and two inner magnetic yokes 13. The two outer magnetic yokes 11 are arranged opposite each other, and the two inner magnetic yokes 13 are arranged opposite each other between the two outer magnetic yokes 11. Permanent magnets 12 are respectively provided on the two inner magnetic yokes 13, and the permanent magnets 12 are located between the outer magnetic yokes 11 and the inner magnetic yokes 13. A coil 14 is provided between the two inner magnetic yokes 13, and an iron core 16 is provided inside the coil 14. The two inner magnetic yokes 13 are respectively bent on the side near the iron core 16. The inner bend 131 has a plane perpendicular to the axial direction of the iron core 16. The inner bend 131 is provided with a relief groove 132 for avoiding the iron core 16. A first air gap 100 is formed around the iron core 16 to contact the inner magnetic yoke 13. The relief groove 132 is semi-circular. Two inner bends 131 are spaced apart. The two relief grooves 132 form an approximately circular hole around one end surface of the iron core 16. The sidewall of the relief groove 132 is an arc-shaped relief surface.

[0035] like Figure 1-3 The iron core 16 is provided with bushings 8 around its perimeter. The distance a from the side wall of the clearance groove 132 to the iron core 16 is greater than the thickness of the bushing 8. The bushing 8 can extend into the first air gap 100 and is spaced apart from the side wall of the clearance groove 132.

[0036] like Figure 3 Preferably, the clearance groove 132 has an arc-shaped clearance surface, and the distance from each position on the clearance surface to the axis of the iron core 16 is equal, that is, in the direction of the plane where the inner bend foot 131 is located, the distance from each position on the clearance surface to the corresponding surface of the iron core 16 is equal and all are 'a'.

[0037] Furthermore, an armature 7 connected to the iron core 16 is provided between the outer magnetic yoke 11 and the inner bent leg 131. The outer magnetic yoke 11 has an outer bent leg 111 that bends towards the iron core 16. The outer bent leg 111 is arranged opposite to the inner bent leg 131. An armature 7 connected to the iron core 16 is provided between the outer bent leg 111 and the inner bent leg 131. A second air gap is provided between the outer bent leg 111 and the inner bent leg 131. In the axial direction of the iron core 16, i.e., in the direction of movement of the iron core 16, the distance from the inner bent leg 131 to the outer bent leg 111 is D1. D1 minus the thickness D2 of the armature 7 is greater than the distance a from the clearance groove 132 to the iron core 16 in the radial direction of the iron core 16, i.e., D1-D2>a.

[0038] Since the magnitude of the electromagnetic force is determined by the magnitude of the magnetic flux density at the air gap on the surface of the armature 7, and the direction is in the direction of the decreasing air gap, the direction of the electromagnetic force is in the direction of the decreasing air gap that produces the maximum electromagnetic force. The first air gap 100 enables the main magnetic circuit to not go directly from the iron core 16 to the inner yoke 13, but must go through the armature 7. Thus, the permanent magnet 12 generates an upward attraction on the armature 7, ensuring the upward force of the iron core 16 and ensuring reliable reset.

[0039] Specifically, the outer magnetic yoke 11 includes a side plate 113, with an upper bent foot 112 and an outer bent foot 111 at each end of the side plate 113. Two inner magnetic yokes 13 are disposed on the inner side of the two side plates 113, and the two side plates 113 and the two inner magnetic yokes 13 are respectively disposed opposite to each other. The permanent magnet 12 is disposed between the side plate 113 and the inner magnetic yokes 13. The outer bent foot 111 and the two inner bent feet 131 are respectively disposed opposite to each other. The armature 7 is disposed between the outer bent foot 111 and the inner bent foot 131. The distance from the inner bent foot 131 to the outer bent foot 111 is D1.

[0040] The second air gap includes an upper air gap and a lower air gap located on both sides of the armature 7. That is, in the axial direction of the iron core 16, the upper air gap is located between the armature 7 and the inner bent leg 131, and the lower air gap is located between the armature 7 and the outer bent leg 111 of the outer magnetic yoke 11. The size of the upper and lower air gaps changes with the movement of the armature 7. When the armature 7 is in contact with the inner bent leg 131, it is the farthest distance from the armature 7 to the outer bent leg 111, which is b. When the armature 7 is in contact with the outer bent leg 111, it is the farthest distance from the armature 7 to the inner bent leg 131, which is c. The distance between b and c is greater than a.

[0041] During the product attraction process, the magnetic force generated by coil 14 is downward. Initially, the force generated by permanent magnet 12 is kept in the open state. As the attraction force of coil 14 increases and the downward stroke changes, the air gap changes accordingly. The direction of the magnetic force always points in the direction of decreasing air gap. After reaching the equilibrium point of air gap, the magnetic force of permanent magnet 12 will change. When the closed state is reached, coil 14 and permanent magnet 12 work together to keep it in the connected state.

[0042] like Figure 5 As shown, in the radial direction of the iron core 16, the minimum distances from the two ends of the armature 7 to the two side plates 113 of the outer magnetic yoke 11 are d, where d>b=c. The lengths of the contact between the side of the armature 7 and the two outer bent feet 111 of the outer magnetic yoke 11 are e, that is, the length of contact between any end of the armature 7 and the outer bent foot 111 is e, where e≤6mm.

[0043] like Figure 4 As shown, after the power is cut off, there is no current in coil 14, and coil 14 does not generate magnetic force; the iron core 16 and armature 7 move upward under the reaction force of spring 1, and armature 7 contacts the inner bent foot 131. At this time, only the first electromagnetic circuit 101 and the second electromagnetic circuit 102 when the permanent magnet 12 is excited are present.

[0044] The first broken electromagnetic path 101 passes through the permanent magnet 12, the outer yoke 11, the iron core 16, the armature 7 and the inner yoke 13 in sequence and then returns to the permanent magnet 12. The first broken electromagnetic path 101 is the path through which the main magnetic flux flows.

[0045] The second broken electromagnetic path 102 passes through the permanent magnet 12, the outer magnetic yoke 11, the second air gap and the inner magnetic yoke 13 in sequence and then returns to the permanent magnet 12. The second broken electromagnetic path 102 is the path through which the leakage flux flows, and the magnetic force is very small relative to the main magnetic path.

[0046] like Figure 5 As shown, after the coil 14 is energized, it overcomes the force of the spring 1 and the magnetic force generated by the permanent magnet 12. The iron core 16 and the armature 7 move downward and push towards the outer yoke 11. During the process of pushing towards the outer yoke 11, the air gap changes. The downward air gap becomes smaller and the direction of the magnetic force of the permanent magnet 12 points in the direction of the decreasing air gap. This becomes the combined effect of the attraction generated by the coil 14 and the attraction generated by the permanent magnet 12, which pushes and holds the outer yoke 11, thus completing the attraction.

[0047] like Figure 5 As shown, after the product is attracted, the coil 14 is continuously energized, and the coil 14 generates a downward magnetic force on the armature 7, compressing the spring 1 and maintaining a stable state of energized attraction; at the same time, the permanent magnet 12 is excited to generate three magnetic circuits, which also generate a downward force on the armature 7, sharing the force of the coil 14 and saving energy. The three magnetic circuits are the first electromagnetic circuit 201, the second electromagnetic circuit 202 and the third electromagnetic circuit 203.

[0048] The first electromagnetic path 201 passes through the permanent magnet 12, the outer yoke 11, the iron core 16, the first air gap 100 and the inner yoke 13 in sequence and then returns to the permanent magnet 12.

[0049] The second electromagnetic path 202 passes through the permanent magnet 12, the outer yoke 11, the armature 7, the moving iron core 16 and the inner yoke 13 in sequence and then returns to the permanent magnet 12.

[0050] The third electromagnetic path 203 passes through the outer magnetic yoke 11, the iron core 16, the armature 7 and the outer magnetic yoke 11 in sequence.

[0051] The main magnetic circuit generated by coil 14 is as follows Figure 5 The third electromagnetic path 203 plays a dominant role, while the second electromagnetic path 202 is its leakage flux. It has the same path as the magnetic flux generated by the permanent magnet 12, but in the opposite direction, thus canceling each other out and producing no additional effect. The effective part of the magnetic circuit generated by the permanent magnet 12 is the second electromagnetic path 202, which remains in a closed state, forming a closed loop and strengthening the attraction state.

[0052] After the coil 14 is de-energized, the force generated by the spring 1 resets and overcomes the force generated by the permanent magnet 12 to start moving. During the reset process, the permanent magnet 12 changes from resistance to attraction as the air gap changes. Together with the force generated by the spring 1, it causes the armature 7 to push against the inward magnetic yoke 13, and the product is released.

[0053] like Figure 1 As shown, the armature 7 is in the shape of a flat plate. The armature 7 is connected to the iron core 16 by screws 3 or rivets. The armature 7 does not need to be connected to the iron core 16 by high-temperature assembly, which can significantly reduce the assembly difficulty.

[0054] Furthermore, the armature 7 is provided with a partition 5 on the side away from the iron core 16, and a support plate 4 is provided on the side of the partition 5 away from the armature 7. The support plate 4, the partition 5 and the armature 7 are connected to the iron core 16 by screws 3 or rivets. The screws 3 or rivets pass through the support plate 4, the partition 5 and the armature 7 in sequence and are then connected to the iron core 16. This not only has the characteristics of convenient assembly, but also the partition 5 can adjust the force of the spring 1, and the support plate 4 can serve as the power source of the mechanism.

[0055] like Figure 1 , 8As shown in Figure -10, the coil frame 15 includes a cylinder 141 and a base 142 and a cover plate 143 integrally formed at both ends of the cylinder 141. A second spring 17 is provided on the cover plate 143. The iron core 16 is installed inside the cylinder 141, and the coil 14 is installed outside the cylinder 141 and located between the base 142 and the cover plate 143. The iron core 16 can move up and down inside the cylinder 141. In this embodiment, the coil frame 15 does not need to be assembled from two independent parts, making it more convenient to use.

[0056] Furthermore, the base 142 is provided with an inner mounting groove 154 and an outer mounting groove 155, which are respectively matched with the inner magnetic yoke 13 and the outer magnetic yoke 11 for limiting cooperation. The base 142 installs the inner magnetic yoke 13 and the outer magnetic yoke 11 through the inner mounting groove 154 and the outer mounting groove 155, which has the advantages of stability and reliability.

[0057] like Figure 1-7 The specific embodiment shown includes an iron core 16, a coil frame 15 for mounting and defining the iron core 16, a coil 14 wound on the coil frame 15, a bracket 2 supporting the coil frame 15, an armature 7 connected to the iron core 16, a spring 1 disposed between the armature 7 and the bracket 2, and a yoke assembly positioned corresponding to the armature 7 and the iron core 16 and fixed on the coil frame 15. The spring 1 drives the armature 7 to move upward when the coil 14 is de-energized.

[0058] The yoke assembly includes a pair of identical C-shaped (or U-shaped) outer yokes 11 facing each other on both sides of the aforementioned iron core 16. On the inner side of each pair of outer yokes 11, there is a permanent magnet 12 and a pair of L-shaped inner yokes 13. The pair of outer yokes 11 form a working space. The iron core 16, armature 7, coil 14, permanent magnet 12, and inner yokes 13 are arranged in the cavity they surround. The permanent magnet 12 is located slightly below the cavity wall of the outer yoke 11 and between it and the inner yoke 13, and is limited by the inner yoke 13.

[0059] The iron core 16 is installed in the coil frame 15 and connected to the armature 7 at the bottom, generally by screws 3, but riveting or other methods can also be used. Below the armature 7, partitions 5, support plates 4, and another partition 5 are installed in sequence and fixed to the iron core 16 with screws 3. The support plate 4 can serve as a power source to drive other mechanisms to move with the iron core 16 (not shown in the figure). The size and structure of the head of the support plate 4 can be designed as needed. The thickness can be adjusted by changing the number of partitions 5, thereby adjusting the reaction force of the screws 3, the vertical position of the support plate 4, and its stroke.

[0060] The armature 7 is installed between the outer bent feet 111 of a pair of outer magnetic yokes 11 and the inner bent feet 131 of a pair of inner magnetic yokes 13. When the coil 14 is released, it resets under the action of the spring 1 and the permanent magnet 12, and contacts the pair of inner magnetic yokes 13. When the coil 14 is engaged, it overcomes the force of the spring 1 and is engaged on the upper bent feet 112 of a pair of outer magnetic yokes 11, remaining stable under the attraction of the coil 14 and the force of the permanent magnet 12. The contact length between the armature 7 and the outer magnetic yoke 11 is e. The smaller the size of e, the greater the magnetic induction intensity, the greater the holding force, and the more reliable the product engagement.

[0061] The iron core 16, armature 7, a pair of inner and outer magnetic yokes 11, and a pair of inner magnetic yokes 13 are all made of magnetically conductive material. That is, magnetically conductive material is used as the iron core 16, armature 7, pair of inner and outer magnetic yokes 11, and pair of inner magnetic yokes 13. In this embodiment, the magnetically conductive material is electrical pure iron or iron, or steel, or silicon steel sheets can also be used.

[0062] The longitudinal cross-section of the iron core 16 is circular or square, and the iron core 16 is directly installed in the coil frame 15 with the coil 14 wound around it. The iron core 16 includes a lower column 161, a middle column 162, and an upper column 163. The lower column 161 is smaller than the middle column 162, and a bushing 8 is installed on its outside. The bushing 8 is made of plastic material such as PBT and is used to change the magnetic permeability and reduce the number of magnetic lines of force passing through it. The upper column 163 of the iron core 16 is used to connect a mechanism (not shown in the figure) that moves under the drive of the iron core. The mechanism drives other parts or contacts to move, such as contactor support. It is connected to the iron core using screws or slotted structures. The movement of the iron core drives the connected parts to move, which in turn drives other parts or the contacts of the parts mounted on them to move, realizing the motion function or the connection and disconnection of the contacts. The upper column 163 of the iron core 16 generally has threaded holes, V-shaped or I-shaped slots to facilitate connection and installation. The upper end of the spring 1 is supported on the armature 7 or the partition 5 below the armature 7, and the lower end is supported on the bracket 2. The bracket 2 is assembled with the coil frame 15 in the form of a snap-fit. Of course, a screw structure is also feasible. A pair of buffers 6 are placed between the outer yoke 11 and the bracket 2. The buffers 6 generate a preload on the bracket 2 to ensure the stability of the position of the bracket 2 and to ensure that the position of the spring 1 does not change, thereby improving the stability of the spring 1.

[0063] like Figure 1 As shown, a pair of C-shaped outer magnetic yokes 11 have an upper bent leg 112 with a length greater than the lower outer bent leg 111. The upper bent leg 112 and the outer bent leg 111 are respectively installed in the corresponding slots of the coil frame 15. The upper bent leg 112 has a concave groove with the same shape as the central column 162. The size of the groove maintains a reliable movement clearance with the central column 162 to ensure that the up and down movement of the iron core 16 is flexible and reliable. The lower outer bent leg 111 is smaller in size and forms a magnetic circuit with the armature 7 in the closed state.

[0064] A pair of inner magnetic yokes 13, which is the biggest difference from conventional magnets, form a new magnetic circuit through the inner bent feet 131. The inner bent feet 131 are provided with concave relief grooves 132, and the relief grooves 132 are provided with relief surfaces corresponding to the shape of the lower column 161, forming a first air gap 100 with a constant distance a. Bosses are stamped on the longitudinal plane of the inner magnetic yokes 13, including an upper limit boss 135, a lower limit boss 133, and left and right limit bosses 134, which are used to limit the installation of the permanent magnet 12.

[0065] like Figure 8 The second specific embodiment shown, Figure 6 exist Figure 2 Based on the above, a second magnetic conductor 18 is added to the end of the iron core 16 away from the first air gap 100, and a sleeve 19 is set between the second magnetic conductor 18 and the iron core 16. The structure of the coil frame 15 and the horizontal shape and structure above the outer magnetic yoke 11 are adjusted accordingly to make the air gap between the outer magnetic yoke 11, the magnetic conductor 18 and the iron core 16 as small as possible while ensuring flexible movement. The magnetic conductor 18 is made of magnetic material. The use of the magnetic conductor increases the longitudinal contact direction with the iron core 16 and improves the stability of the magnetic circuit.

[0066] like Figure 9-10 As shown, the coil frame 15 has a through hole 151 in the middle, through which the iron core 16 can move freely. The coil frame 15 has two sections of different thicknesses in the middle, with the thicker section accommodating the magnetic conductor 18. The coil frame 15 has mounting slots at the top and bottom for mounting the outer yoke 11 and the yoke 13. The upper slot 153 of the coil frame 15 mounts the upper bent foot 112 above the outer yoke 11, the outer mounting slot 155 mounts the lower bent foot 111 below the outer yoke 11, and the inner mounting slot 154 mounts the inner bent foot 131 of the yoke 13, thus limiting, positioning, and fixing the yoke. The lower boss 156 is used for mounting on the bracket 2.

[0067] It should be noted that in the description of this invention, the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship conventionally placed during use. They are used only for ease of description and do not indicate that the device or element referred to must have a specific orientation. Therefore, they should not be construed as limiting this invention. Furthermore, the terms "first," "second," and "third," etc., are used only to distinguish descriptions and should not be construed as indicating relative importance.

[0068] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An electromagnetic mechanism comprising a coil (14), an iron core (16) disposed within the coil (14), two outer magnetic yokes (11) and two inner magnetic yokes (13), wherein the two outer magnetic yokes (11) are disposed opposite to each other, and the two inner magnetic yokes (13) are disposed opposite to each other between the two outer magnetic yokes (11), and permanent magnets (12) are respectively disposed on the two inner magnetic yokes (13), the permanent magnets (12) being located between the outer magnetic yokes (11) and the inner magnetic yokes (13), the coil (14) is disposed between the two inner magnetic yokes (13), and an iron core (16) is disposed inside the coil (14), wherein the two inner magnetic yokes (13) are provided with inwardly bent feet (131) on the side near the iron core (16) and bent toward the iron core (16). Its features are: The inner bend (131) is provided with a relief groove (132) for avoiding the iron core (16), and the two inner bends (131) are spaced apart, forming a first air gap (100) between the iron core (16) and the inner bends (131). The outer magnetic yoke (11) includes a side plate (113), with an upper bent foot (112) and an outer bent foot (111) respectively at both ends of the side plate (113). The permanent magnet (12) is disposed between the side plate (113) and the inner magnetic yoke (13). The outer bent foot (111) and the inner bent foot (131) are disposed opposite to each other. An armature (7) connected to the iron core (16) is disposed between the outer bent foot (111) and the inner bent foot (131). A second air gap is provided between the outer bend (111) and the inner bend (131). The second air gap includes an upper air gap and a lower air gap located on both sides of the armature (7). That is, in the axial direction of the iron core (16), the upper air gap is located between the armature (7) and the inner bend (131), and the lower air gap is located between the armature (7) and the outer bend (111) of the outer magnetic yoke (11). The armature (7) and the inner bend (131) are connected... When in contact, the armature (7) is the farthest distance from the outer bent foot (111), the farthest distance from the armature (7) to the outer bent foot (111) is b, when the armature (7) contacts the outer bent foot (111), the armature (7) is the farthest distance from the inner bent foot (131), the farthest distance from the armature (7) to the inner bent foot (131) is c, the distance from the side wall of the clearance groove (132) to the iron core (16) is a, and b = c > a; The length of the upper bent leg (112) is greater than the length of the outer bent leg (111). The lengths of the contact between the side of the armature (7) and the two outer bent legs (111) of the outer magnetic yoke (11) are respectively e. In the radial direction of the iron core (16), the minimum distances from the two ends of the armature (7) to the two side plates (113) of the outer magnetic yoke (11) are respectively d, where d>b=c; When the coil (14) is energized and attracted, the armature (7) overcomes the force of the spring (1) and is attracted to the upper bent feet (112) of the two outer magnetic yokes (11). When the coil (14) is de-energized and released, the armature (7) is reset under the action of the spring (1) and the permanent magnet (12) and comes into contact with the two inner magnetic yokes (13).

2. The electromagnetic mechanism according to claim 1, characterized in that: The iron core (16) is provided with bushings (8) around its perimeter. The distance a from the side wall of the clearance groove (132) to the iron core (16) is greater than the thickness of the bushing (8). The bushing (8) extends into the first air gap (100) and is spaced apart from the side wall of the clearance groove (132).

3. The electromagnetic mechanism according to claim 1, characterized in that: The sidewall of the clearance groove (132) is an arc-shaped clearance surface, and the distance from each position on the clearance surface to the corresponding surface of the iron core (16) is equal and is a.

4. The electromagnetic mechanism according to claim 1, characterized in that: The length e of the contact between one end of the armature (7) and the outer bent foot (111) is less than or equal to 6 mm.

5. The electromagnetic mechanism according to claim 1, characterized in that: When the coil (14) is energized, the permanent magnet (12) generates a first electromagnetic path (201), a second electromagnetic path (202) and a third electromagnetic path (203) respectively; The first electromagnetic path (201) passes through the permanent magnet (12), the outer yoke (11), the iron core (16), the first air gap (100) and the inner yoke (13) in sequence and then returns to the permanent magnet (12); The second electromagnetic path (202) passes through the permanent magnet (12), the outer yoke (11), the armature (7), the moving iron core (16) and the inner yoke (13) in sequence and then returns to the permanent magnet (12); The third electromagnetic path (203) passes through the outer magnetic yoke (11), the iron core (16), the armature (7), and the outer magnetic yoke (11) in sequence.

6. The electromagnetic mechanism according to claim 1, characterized in that: The iron core (16) is provided with a second magnetic conductor (18) at one end away from the first air gap (100), and a sleeve (19) is provided between the second magnetic conductor (18) and the iron core (16).

7. The electromagnetic mechanism according to claim 1, characterized in that: One side of the armature (7) is connected to one end of the iron core (16). The armature (7) has a partition (5) on the side away from the iron core (16). The partition (5) has a support plate (4) on the side away from the armature (7). The support plate (4), the partition (5) and the armature (7) are connected to the iron core (16) by screws (3) or rivets.

8. The electromagnetic mechanism according to claim 1, characterized in that: The coil (14) is mounted on the coil frame (15), which includes a cylinder (141) and a base (142) and a cover plate (143) integrally formed at both ends of the cylinder (141). The iron core (16) is mounted inside the cylinder (141), and the coil (14) is mounted outside the cylinder (141) and located between the base (142) and the cover plate (143). The base (142) is provided with an inner mounting groove (154) and an outer mounting groove (155), which are respectively matched with the inner magnetic yoke (13) and the outer magnetic yoke (11).

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