Moving iron unit, hearing aid and assembly method of moving iron unit

Abstract

The invention discloses a moving iron unit, a hearing aid and an assembling method of the moving iron unit. The moving iron unit comprises a magnet yoke, a first magnet, a second magnet, a driving assembly, an induction coil, a vibration unit and a support. A cavity is defined by the magnet yoke, the first magnet and the second magnet are arranged in the cavity, and a gap is formed between the first magnet and the second magnet; the induction coil has a central hole; the driving assembly comprises a balance armature and a driving rod, the balance armature penetrates through the center hole and the interval in a suspended mode, and the driving rod is connected with the balance armature and the vibration unit. The driving assembly drives the vibration unit to vibrate under the condition that the induction coil is electrified; the magnet yoke and the induction coil are limited on the bracket, so that the connection condition of the driving rod and the vibration unit / balance armature can be conveniently checked in the assembling process of the moving iron unit; and meanwhile, the magnet yoke and the induction coil are respectively isolated from the shell of the moving iron unit by the bracket, so that noise and squeal can be reduced from the source.

Description

Assembly method of balanced armature driver, hearing aid and balanced armature driver Technical Field

[0001] This invention relates to the field of acoustic technology, and more particularly to a balanced armature driver, a hearing aid, and a method for assembling the balanced armature driver. Background Technology

[0002] Balanced armature drivers offer advantages such as excellent sound isolation, small size, and high sensitivity, and are widely used in headphones, speakers, and hearing aids. The core components of a balanced armature driver include a housing, diaphragm assembly, balanced armature (armature), pins, and components that generate a magnetic field. The pins connect to the balanced armature and diaphragm assembly, causing the diaphragm assembly to vibrate and produce sound. Typically, a balanced armature driver also includes a housing that encloses all the core components. For ease of installation, the housing usually consists of an upper shell and a lower shell. During installation, the upper shell and diaphragm assembly are mounted together; the components that generate the magnetic field (including the induction coil and yoke) are glued or soldered to the inside of the lower shell, and then the upper and lower shells are connected together to complete the assembly. The drawbacks of this design are twofold: First, the guide pin's diameter is extremely small, making it prone to misalignment. During assembly, it's impossible to inspect the connection between the guide pin and the diaphragm assembly, as well as the connection between the guide pin and the balance armature. Second, the components generating the magnetic field are often made of metal, and the lower casing is also typically metal. This direct contact between the magnetic field-generating components and the lower casing easily leads to resonance, causing intense vibrations in the entire balanced armature driver and affecting sound quality. This is particularly problematic in hearing aids, where the balanced armature driver and microphone are very close together. The vibrations of the balanced armature driver are easily picked up by the microphone, resulting in noise and feedback. Currently, the industry typically uses software algorithms to address noise reduction, but this undoubtedly increases design complexity and cost, and its reliability is questionable. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide an improved method for assembling a balanced armature driver, a hearing aid, and a balanced armature driver, addressing at least one of the deficiencies mentioned in the background art.

[0004] The technical solution adopted by the present invention to solve its technical problem is as follows: a moving iron unit is provided, which includes a magnetic yoke, a first magnet, a second magnet, a driving assembly, an induction coil, a vibration unit, and a support; the magnetic yoke encloses a cavity, the first magnet and the second magnet are disposed in the cavity, and a gap is formed between the first magnet and the second magnet; the induction coil has a central hole; the driving assembly includes a balancing armature and a driving rod, the balancing armature is suspended through the central hole and the gap respectively, and the driving rod is connected to the balancing armature and the vibration unit respectively; the driving assembly drives the vibration unit to vibrate when the induction coil is energized; the magnetic yoke and the induction coil are confined on the support.

[0005] Preferably, the bracket includes a base and a partition wall connected to each other, the magnetic yoke and the induction coil are limited on the base, and the magnetic yoke and the induction coil are separated on opposite sides of the partition wall; the partition wall is provided with a through hole, the through hole is connected to the spacer and the center hole respectively, and the balance armature also passes through the through hole.

[0006] Preferably, the longitudinal dimension of the through hole is smaller than the longitudinal dimension of the interval.

[0007] Preferably, the balance armature abuts against the top of the partition wall.

[0008] Preferably, the partition wall has at least one limiting groove, the magnetic yoke has at least one limiting protrusion, and the limiting protrusion and the limiting groove are engaged.

[0009] Preferably, the bracket is provided with a first mounting groove, and the magnetic yoke is at least partially embedded in the first mounting groove for positioning. And / or, the bracket is provided with a second mounting groove, and the induction coil is at least partially embedded in the second mounting groove for positioning.

[0010] Preferably, the vibration unit is also positioned on the support.

[0011] Preferably, the support includes a base, a partition wall, and a top seat, the partition wall being connected to the base and the top seat respectively; the magnetic yoke and the induction coil are limited on the base, and the magnetic yoke and the induction coil are separated on opposite sides of the partition wall; the vibration unit is connected to the top seat.

[0012] Preferably, the moving iron unit further includes at least two conductive elements, the induction coil has at least two wire ends, the wire ends and the conductive elements are connected in a one-to-one correspondence, and the conductive elements are limited on the bracket.

[0013] Preferably, the moving iron unit further includes a housing, which includes an upper shell and a lower shell. The upper shell and the lower shell are connected and together enclose a receiving space. The magnetic yoke, the first magnet, the second magnet, the drive assembly, the induction coil, the vibration unit, and the support are all disposed within the receiving space. The vibration unit is connected to the upper shell, and the support is connected to the lower shell. The vibration frequency of the support is different from the vibration frequency of the lower shell.

[0014] The present invention also provides a hearing aid comprising the moving iron unit described in any of the above claims.

[0015] The present invention also provides a method for assembling a moving iron unit, comprising the following steps: connecting an upper shell and a vibration unit; fixing a first magnet and a second magnet respectively into the cavity formed by the magnetic yoke, with a gap between the first magnet and the second magnet; mounting an induction coil and the magnetic yoke respectively on a bracket; passing a balancing armature through the central hole of the induction coil and the gap; connecting one end of a drive rod to the balancing armature and the other end of the drive rod to the vibration unit; checking the connection between the drive rod and the vibration unit; and / or checking the connection between the drive rod and the balancing armature; after confirming that the connection is correct, connecting the lower shell to the upper shell and the bracket respectively.

[0016] The present invention has at least the following beneficial effects: the magnetic yoke and the induction coil are confined on the bracket. Therefore, on the one hand, it facilitates the inspection of the connection between the drive rod and the vibration unit, as well as the connection between the drive rod and the balance armature, during the assembly of the moving iron unit; on the other hand, the bracket isolates the magnetic yoke and the induction coil from the outer shell of the moving iron unit, preventing direct contact between the magnetic yoke and the induction coil and the outer shell of the moving iron unit, thus avoiding resonance and reducing noise and howling at the source. Furthermore, it eliminates the need for software algorithms to filter noise, resulting in better reliability and reduced design difficulty and cost. Attached Figure Description

[0017] To more clearly illustrate the technical solution of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. In the drawings: Figure 1 is a three-dimensional structural schematic diagram of the moving iron unit in some embodiments of the present invention; Figure 2 is a longitudinal cross-sectional structural schematic diagram of the moving iron unit shown in Figure 1; Figure 3 is a structural schematic diagram of the moving iron unit shown in Figure 1 after the outer shell is hidden; Figure 4 is an exploded structural schematic diagram of the moving iron unit shown in Figure 3; Figure 5 is a structural schematic diagram of the moving iron unit in some embodiments of the present invention in an intermediate state during the assembly process; Figure 6 is a structural schematic diagram of the components shown in Figure 5 after they are connected together; Figure 7 is a three-dimensional structural schematic diagram of the support of the moving iron unit in some embodiments of the present invention; Figure 8 is an enlarged structural schematic diagram of part A in Figure 2; Figure 9 is an exploded structural schematic diagram of the moving iron unit and circuit board not connected in some embodiments of the present invention; Figure 10 is a structural schematic diagram of the moving iron unit and circuit board connected together in Figure 9; Figure 11 is a structural schematic diagram of the moving iron unit shown in Figure 9 after the outer shell is hidden; Figure 12 is a partially exploded structural schematic diagram of the moving iron unit after the outer shell is hidden in other embodiments of the present invention. Detailed Implementation

[0018] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the invention are now described in detail with reference to the accompanying drawings. In the following description, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "linking," "fixing," and "setting" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements or an interaction between two elements. When an element is referred to as being "on" or "below" another element, the element can be located "directly" or "indirectly" on the other element, or there may be one or more intermediary elements. The terms "first," "second," "third," etc., are used only for the convenience of describing the technical solution and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features.

[0019] Please refer to Figures 1 to 4. This invention illustrates a moving iron unit, which includes a magnetic yoke 1, a first magnet 21, a second magnet 22, a drive assembly 3, an induction coil 4, a vibration unit 5, and a support 7. This moving iron unit can be applied to sound-producing devices such as headphones, speakers, and hearing aids.

[0020] The magnetic yoke 1 encloses a closed annular cavity, within which a first magnet 21 and a second magnet 22 are disposed. The first magnet 21 and the second magnet 22 are respectively attached to the upper and lower surfaces inside the cavity of the magnetic yoke 1. A gap 20 is formed between the first magnet 21 and the second magnet 22. Figures 2 and 3 illustrate the longitudinal direction Y, which refers to the vertical direction of the moving iron unit in its normal placement state. The first magnet 21 and the second magnet 22 are spaced 20 along the longitudinal direction Y.

[0021] The induction coil 4 has a central hole 40. The induction coil 4 is formed by winding wires, and the central hole 40 is located inside all the wires. The drive assembly 3 includes a balancing armature 31 and a drive rod 32. The balancing armature 31 passes through the central hole 40 and the gap 20 in a suspended state; that is, the balancing armature 31 is in a "suspended" state in both the central hole 40 and the gap 20, and the induction coil 4, the first magnet 21, and the second magnet 22 are not in contact with the balancing armature 31. The drive rod 32 is connected to the balancing armature 31 and the vibration unit 5. The drive rod 32 acts as a connecting bridge between the balancing armature 31 and the vibration unit 5 and can transmit force.

[0022] When the induction coil 4 is energized, the drive component 3 drives the vibration unit 5 to vibrate. Specifically, the sound generation principle of the moving iron unit mainly adopts the basic principle of electromagnetic conversion. When the moving iron unit is working, the induction coil 4 is connected to the power supply, and the alternating current signal passes through the induction coil 4. The induction coil 4 is magnetized, which magnetizes the balance armature 31 placed in the middle of the induction coil 4. The magnetized balance armature 31 vibrates up and down along the longitudinal direction Y in the interval 20 between the first magnet 21 and the second magnet 22 according to the principle that like poles repel and unlike poles attract. This drives the drive rod 32 to vibrate up and down along the longitudinal direction Y. At the same time, the drive rod 32 also drives the vibration unit 5 to vibrate up and down, which in turn agitates the air in the cavity, thereby producing sound.

[0023] The magnetic yoke 1 and the induction coil 4 are positioned on the bracket 7. This serves two purposes: firstly, it facilitates inspection of the connection between the drive rod 32 and the vibration unit 5, as well as the connection between the drive rod 32 and the balance armature 31, during the assembly of the moving iron unit; secondly, the bracket 7 isolates the magnetic yoke 1 and the induction coil 4 from the housing 6 of the moving iron unit, preventing direct contact and resonance. This reduces noise and howling at the source, eliminates the need for software algorithms to filter noise, improves reliability, and lowers design complexity and cost.

[0024] Specifically, as shown in Figures 1, 2, 5, and 6, in some embodiments, the moving iron unit further includes a housing 6. The housing 6 includes an upper housing 61 and a lower housing 62. When the moving iron unit is assembled, the upper housing 61 and the lower housing 62 are connected and together enclose a receiving space. The magnetic yoke 1, the first magnet 21, the second magnet 22, the drive assembly 3, the induction coil 4, the vibration unit 5, and the support 7 are all disposed within the receiving space. The vibration unit 5 is connected to the upper housing 61, and the support 7 is connected to the lower housing 62.

[0025] Please refer to Figures 5, 6, and 1. The assembly method of the moving iron unit includes at least the following steps: As shown in Figure 5, the upper shell 61 and the vibration unit 5 are connected. After the upper shell 61 and the vibration unit 5 are assembled together, a first assembly 81 is formed. The first magnet 21 and the second magnet 22 are respectively installed and fixed into the cavity formed by the magnetic yoke 1; a gap 20 is formed between the first magnet 21 and the second magnet 22. The induction coil 4 and the magnetic yoke 1 are respectively mounted on the bracket 7, and the balance armature 31 is passed through the center hole 40 of the induction coil 4 and the gap 20. After the first magnet 21, the second magnet 22, the magnetic yoke 1, the induction coil 4, the balance armature 31, the drive rod 32, and the bracket 7 are assembled, a second assembly 82 is formed. Subsequently, the first assembly 81 and the second assembly 82 are assembled together, that is, one end of the drive rod 32 is connected to the balance armature 31, and the other end of the drive rod 32 is connected to the vibration unit 5. The assembled shape is shown in Figure 6.

[0026] As shown in Figure 6, the position of the drive rod 32 can be clearly seen, thus allowing for the inspection of the connection between the drive rod 32 and the vibration unit 5. And / or, the connection between the drive rod 32 and the balance armature 31 can also be inspected. That is, in this step, the connections between the drive rod 32 and the vibration unit 5, and between the drive rod 32 and the balance armature 31, can be inspected simultaneously; or, only one connection (between the drive rod 32 and the vibration unit 5 or between the drive rod 32 and the balance armature 31) can be inspected.

[0027] After verifying that everything is correct, connect the lower shell 62 to the upper shell 61 and the bracket 7 respectively, forming the shape shown in Figure 1.

[0028] In this design, the vibration frequencies of the support 7 and the lower shell 62 are different to avoid resonance between them. That is, the natural frequencies of the support 7 and the lower shell 62 are different. For example, the materials used in their construction can be differentiated in terms of stiffness and mass. The stiffness of the support 7 and the lower shell 62 are different. And / or, the mass of the support 7 and the lower shell 62 can also be different. In some embodiments, the support 7 is made of plastic, and the lower shell 62 is made of metal. Because the vibration frequencies of plastic and metal are different, resonance between the support 7 and the lower shell 62 can be effectively avoided. Furthermore, the magnetic yoke 1 and the lower shell 62 are isolated by the support 7, thereby reducing the overall vibration of the moving iron unit from the physical structure level, reducing noise, which is particularly suitable for hearing aids.

[0029] The present invention also provides a hearing aid, which includes a balanced armature unit according to any embodiment. Other specific structures of the hearing aid adopt mature existing technologies and will not be described in detail here. Since the distance between the balanced armature unit and the microphone (pickup unit) in the hearing aid is very small, setting a bracket 7 in the balanced armature unit of the hearing aid as an isolation component can reduce unnecessary vibrations (vibrations other than the vibration of the vibration unit 5 and the drive unit), thereby reducing noise and improving sound quality.

[0030] As shown in Figures 2 to 7, in some embodiments, the support 7 includes a connected base 71 and a partition wall 72. The yoke 1 and the induction coil 4 are positioned on the base 71. The yoke 1 and the induction coil 4 are separated on opposite sides of the partition wall 72, thereby preventing physical contact interference between the yoke 1 and the induction coil 4. The partition wall 72 is provided with a through hole 720, which extends laterally through the partition wall 72. The through hole 720 connects the spacer 20 and the center hole 40, respectively, and the balance armature 31 also passes through the through hole 720. That is, the balance armature 31 passes through the center hole 40, the through hole 720, and the spacer 20 sequentially in the lateral direction (perpendicular to the longitudinal direction Y). Specifically, the base 71 extends laterally, and the partition wall 72 extends longitudinally, making the support 7 generally inverted T-shaped. The balance armature 31 is generally U-shaped, with its lower half suspended through the central hole 40, through hole 720 and spacer 20, and connected to the drive rod 32; the upper half of the balance armature 31 can abut against the upper surface of the yoke 1 and / or the support 7.

[0031] As shown in Figures 2 and 8, in some embodiments, the dimension of the through hole 720 along the longitudinal direction Y is smaller than the dimension of the interval 20 along the longitudinal direction Y. Simultaneously, the dimension of the through hole 720 along the longitudinal direction Y is also smaller than the dimension of the central hole 40 of the induction coil 4 along the longitudinal direction Y. Therefore, the through hole 720 restricts the vertical displacement of the balance armature 31 along the longitudinal direction Y, and the maximum vertical displacement of the balance armature 31 along the longitudinal direction Y is equal to the dimension of the through hole 720 along the longitudinal direction Y. When the sound-generating device is dropped or bumped, the force is transmitted to the components inside the moving iron unit, especially the balance armature 31, which will vibrate significantly. If the balance armature 31 touches the induction coil 4, the first magnet 21, or the second magnet 22 during vibration, it will cause damage or even destruction to the components. Because the through hole 720 restricts the vertical displacement of the balance armature 31 along the longitudinal direction Y, even if the balance armature 31 vibrates significantly when the sound-generating device is dropped or bumped, it will not collide with or come into contact with the induction coil 4, the first magnet 21, or the second magnet 22, thus providing excellent drop protection. To further enhance its anti-drop properties, the bracket 7 can be made of soft / elastic materials such as rubber or silicone, which can buffer the force exerted when the balance armature 31 contacts the inner wall of the through hole 720 under large-amplitude vibration, thereby reducing the risk of vibration wear on the balance armature 31.

[0032] As shown in Figures 2 to 7, in some embodiments, the balance armature 31 abuts against the top of the partition wall 72. That is, the bracket 7 also provides a support surface for the balance armature 31. Specifically, as shown in Figure 7, in some embodiments, the top surface of the partition wall 72 is recessed downward along the longitudinal direction Y to form a first slot 701. The first slot 701 has the same transverse dimension as the balance armature 31, so that the balance armature 31 can be embedded in the first slot 701 for positioning, and the bottom surface of the first slot 701 contacts the balance armature 31 as a support surface.

[0033] As shown in Figures 4 to 7, in some embodiments, the partition wall 72 has at least one limiting groove 703, and the magnetic yoke 1 has at least one limiting protrusion 11, which engages with the limiting groove 703. That is, the magnetic yoke 1 and the bracket 7 are fixed by the cooperation of the limiting protrusion 11 and the limiting groove 703. Specifically, as shown in Figure 7, in some embodiments, there are four limiting grooves 703, each of which extends laterally through the partition wall 72. The corresponding number of limiting protrusions 11 is also four. It can be understood that the number of limiting grooves 703 and limiting protrusions 11 is the same, or it can be one, two, three, five, etc., without limitation. Further, as shown in Figure 7, in some embodiments, at least one limiting groove 703 is connected to the first card slot 701. Therefore, as shown in Figure 5, after the balance armature 31 is engaged in the first slot 701 and the limiting protrusion 11 of the magnetic yoke 1 is engaged in the limiting groove 703, the balance armature 31 can still be in contact with the upper surface of the magnetic yoke 1. Alternatively, in some other embodiments, the limiting groove 703 and the first slot 701 may not be connected.

[0034] As shown in Figure 7, in some embodiments, the bracket 7 has a first mounting groove 74, and the magnetic yoke 1 is at least partially embedded in the first mounting groove 74 for positioning. The bracket 7 has a second mounting groove 75, and the induction coil 4 is at least partially embedded in the second mounting groove 75 for positioning. Specifically, the first mounting groove 74 and the second mounting groove 75 each penetrate the base 71 along the longitudinal direction Y, making the base 71 have a hollowed-out frame shape. Alternatively, in some other embodiments, the first mounting groove 74 and the second mounting groove 75 may not penetrate the base 71.

[0035] As shown in Figures 9 to 11, in some embodiments, the moving iron unit further includes at least two conductive elements 90. The induction coil 4 has at least two wire ends 41, which are connected to the conductive elements 90 in a one-to-one correspondence. The conductive elements 90 are positioned on the bracket 7. The conductive elements 90 are used to connect the wires of the induction coil 4 to the external circuit board 91, so that the induction coil 4 and the circuit board 91 are electrically connected. Therefore, at least one surface of the conductive element 90 faces the outside of the housing 6 for connecting the circuit board 91. The circuit board 91 and the conductive element 90 can be connected by soldering. The conductive element 90 and the wires of the induction coil 4 can be connected by soldering. Correspondingly, in the third step of the method of assembling the moving iron unit, after connecting the lower housing 62 to the upper housing 61 and the bracket 7 respectively to form the shape shown in Figure 1, it may further include: connecting the circuit board 91 and the conductive element 90 together.

[0036] Further, as shown in Figures 7 and 11, in some embodiments, the base 71 of the bracket 7 has at least two second slots 702 formed on the side near the induction coil 4. The number of second slots 702 is the same as the number of conductive elements 90. The conductive elements 90 and the second slots 702 are fitted together in a one-to-one correspondence. Specifically, the second slot 702 can be an L-shaped slot. Correspondingly, each conductive element 90 is also L-shaped. That is, the second slot 702 includes a first region 702A with an opening facing the vibration unit 5 (i.e., upward) and a second region 702B with an opening facing the circuit board 91 (i.e., laterally outward). Correspondingly, each conductive element 90 includes a first surface facing the vibration unit 5 (i.e., upward) and a second surface facing the circuit board 91 (i.e., laterally outward). The first surface is adapted to the first region 702A; the second surface is adapted to the second region 702B. The wire end 41 of the induction coil 4 is welded to the first surface to form a solder joint. The circuit board 91 and the second surface are welded together. That is, the solder joints of the circuit board 91 and the conductive component 90 avoid the solder joints of the induction coil 4 and the conductive component 90. This avoids the solder joints of the induction coil 4 being affected during the soldering of the circuit board 91 and the conductive component 90, such as causing the solder joints of the induction coil 4 to melt and resulting in electrical connection failure.

[0037] As shown in Figure 12, in some embodiments, the vibration unit 5 is also positioned on the bracket 7. That is, the bracket 7 also provides a support surface for the vibration unit 5. This facilitates assembly and allows for more precise positioning of the vibration unit 5, thereby ensuring a correct connection between the vibration unit 5 and the drive rod 32. Further, in some embodiments, the bracket 7 also includes a top seat 73, located above the partition wall 72, which is connected to both the base 71 and the top seat 73. The vibration unit 5 is connected to the top seat 73. The top seat 73 can be a hollow frame structure. The top seat 73, partition wall 72, and base 71 can be an integrally formed structure or a separate structure (formed separately and then connected as one unit).

[0038] In some embodiments, the vibration unit 5 includes a diaphragm 51 and a diaphragm support 52, the diaphragm support 52 being used to fix the diaphragm 51. The diaphragm support 52 includes a frame structure, the diaphragm 51 is connected to the inner side of the frame structure, and the diaphragm 51 is tautly fixed to the diaphragm support 52 around its perimeter. The drive rod 32 is connected to the diaphragm 51. When the induction coil 4 is energized, the balance armature 31 vibrates up and down, driving the drive rod 32 to vibrate up and down. The drive rod 32 drives the diaphragm 51 to vibrate up and down. When the diaphragm 51 vibrates up and down, it agitates the air in the cavity, thereby producing sound. The diaphragm support 52 is connected to the top seat 73 of the support 7.

[0039] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A moving iron unit, characterized in that, The assembly includes a magnetic yoke (1), a first magnet (21), a second magnet (22), a drive assembly (3), an induction coil (4), a vibration unit (5), and a support (7). The magnetic yoke (1) forms a cavity, in which the first magnet (21) and the second magnet (22) are disposed, and a gap (20) is formed between the first magnet (21) and the second magnet (22). The induction coil (4) has a central hole (40). The drive assembly (3) includes a balance armature (31) and a drive rod (32). The balance armature (31) passes through the central hole (40) and the gap (20) respectively, and the drive rod (32) is connected to the balance armature (31) and the vibration unit (5) respectively. When the induction coil (4) is energized, the drive assembly (3) drives the vibration unit (5) to vibrate. The magnetic yoke (1) and the induction coil (4) are confined on the support (7).

2. The moving iron unit according to claim 1, characterized in that, The bracket (7) includes a base (71) and a partition wall (72) connected to each other. The magnetic yoke (1) and the induction coil (4) are limited on the base (71). The magnetic yoke (1) and the induction coil (4) are separated on opposite sides of the partition wall (72). The partition wall (72) is provided with a through hole (720). The through hole (720) connects the interval (20) and the center hole (40) respectively. The balance armature (31) also passes through the through hole (720).

3. The moving iron unit according to claim 2, characterized in that, The longitudinal dimension of the through hole (720) is smaller than the longitudinal dimension of the interval (20).

4. The moving iron unit according to claim 2, characterized in that, The balance armature (31) abuts against the top of the partition wall (72).

5. The moving iron unit according to claim 2, characterized in that, The partition wall (72) has at least one limiting groove (703), and the magnetic yoke (1) has at least one limiting protrusion (11), which is engaged with the limiting groove (703).

6. The moving iron unit according to claim 1, characterized in that, The bracket (7) is provided with a first mounting groove (74), and the magnetic yoke (1) is at least partially embedded in the first mounting groove (74) for limiting; and / or, the bracket (7) is provided with a second mounting groove (75), and the induction coil (4) is at least partially embedded in the second mounting groove (75) for limiting.

7. The moving iron unit according to claim 1, characterized in that, The vibration unit (5) is also positioned on the bracket (7).

8. The moving iron unit according to claim 7, characterized in that, The support (7) includes a base (71), a partition wall (72) and a top seat (73), the partition wall (72) being connected to the base (71) and the top seat (73) respectively; the magnetic yoke (1) and the induction coil (4) are limited on the base (71), the magnetic yoke (1) and the induction coil (4) are separated on opposite sides of the partition wall (72); the vibration unit (5) is connected to the top seat (73).

9. The moving iron unit according to claim 1, characterized in that, The moving iron unit also includes at least two conductive elements (90), the induction coil (4) has at least two wire ends (41), the wire ends (41) and the conductive elements (90) are connected one-to-one, and the conductive elements (90) are limited on the bracket (7).

10. The moving iron unit according to claim 1, characterized in that, The moving iron unit also includes a housing (6), which includes an upper shell (61) and a lower shell (62). The upper shell (61) and the lower shell (62) are connected and together enclose a receiving space. The magnetic yoke (1), the first magnet (21), the second magnet (22), the drive assembly (3), the induction coil (4), the vibration unit (5), and the bracket (7) are all disposed in the receiving space. The vibration unit (5) is connected to the upper shell (61), and the bracket (7) is connected to the lower shell (62). The vibration frequency of the bracket (7) is different from that of the lower shell (62).

11. A hearing aid, characterized in that, Includes the moving iron unit as described in any one of claims 1 to 10.

12. A method for assembling a moving iron unit, characterized in that, Includes the following steps: Connect the upper shell (61) and the vibration unit (5); fix the first magnet (21) and the second magnet (22) into the cavity formed by the yoke (1), with a gap (20) between the first magnet (21) and the second magnet (22); install the induction coil (4) and the yoke (1) on the bracket (7); pass the balance armature (31) through the center hole (40) of the induction coil (4) and the gap (20); connect one end of the drive rod (32) to the balance armature (31) and the other end of the drive rod (32) to the vibration unit (5); check the connection between the drive rod (32) and the vibration unit (5); and / or check the connection between the drive rod (32) and the balance armature (31); after checking that there are no errors, connect the lower shell (62) to the upper shell (61) and the bracket (7).

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