CN112911469B - Electromagnetic transducer - Google Patents

Abstract

The invention provides an electromagnetic transducer, which comprises a cylinder, a fixed seat, a radiation piece, a tension structure and K permanent magnets, wherein the fixed seat is arranged on the cylinder; one side or two sides of the fixed seat are provided with radiation pieces; the radiation piece is fixedly provided with an armature towards one side of the fixed seat, the fixed seat is fixedly provided with an excitation structure towards each side of the radiation piece, the excitation structure is provided with an E-shaped structure or is integrally in an E-shaped structure, the opening of the E-shaped structure faces the armature and is formed by a base, a first bulge part, a second bulge part and a third bulge part, and a driving coil is wound on the second bulge part; the K permanent magnets are symmetrically distributed about the axis of the E-shaped structure, each permanent magnet is arranged on a path through which a first magnetic line of force passes passing through the permanent magnet, and the height direction of each permanent magnet is parallel to the first magnetic line of force passing through the permanent magnet. By arranging the permanent magnet, the coil current does not need to establish a bias magnetic field any more, the number of turns of the electromagnet is greatly reduced, the loss is reduced, and the energy conversion efficiency is improved.

Description

Electromagnetic transducer

Technical Field

The invention relates to an electromagnetic transducer, in particular to a hybrid excitation high-power low-frequency electromagnetic transducer used in the fields of underwater remote communication, deep sea resource exploration, underwater acoustic tomography and the like.

Background

There are extremely abundant resources in the ocean and full exploitation of ocean resources relies on effective surveying measures. Compared with light waves and radio waves, the energy attenuation of sound waves is small when the sound waves propagate in water (the attenuation rate is one thousandth of the electromagnetic waves), and the lower the frequency of the sound waves is, the longer the propagation distance in water is, so that the low-frequency electromagnetic transducer is widely applied to the fields of ocean research, deep sea resource exploration, underwater acoustic tomography and the like.

An electroacoustic transducer is a device capable of converting electrical energy into acoustic energy. In the low frequency range, the magnetostrictive transducer and the piezoelectric transducer which meet the requirement of high-power transmission are necessarily limited by factors of high manufacturing cost, large volume, large mass and the like, and moving-coil type and explosive type ultralow frequency sound sources have a series of problems of poor stability, low power, poor continuity and the like. The electromagnetic transducer has the advantages of simple structure and stable performance, and can realize larger volume displacement on the premise of smaller volume and lighter weight, thereby realizing low-frequency high-power transmission. Existing electromagnetic transducers typically take the form of alternating current excitation. In such an excitation mode, the frequency of the acoustic wave output by the transducer is twice the electrical end frequency, regardless of the magnitude of the ac excitation current, as determined by the nonlinear transduction mechanism inherent in the excitation mode. The nonlinearity caused by the frequency doubling transduction characteristic can cause the output sound wave to contain larger harmonic components, and the transduction efficiency is lower.

Disclosure of Invention

The invention provides an electromagnetic transducer aiming at the problems of high output harmonic content and low transduction efficiency of the traditional frequency multiplication excitation electromagnetic transducer.

The technical scheme of the invention is as follows: an electromagnetic transducer comprises a cylinder body, wherein the cylinder body is of a rotating body structure, a first direction is defined as the length direction of the cylinder body, the electromagnetic transducer further comprises a fixed seat fixedly connected with the cylinder body and a radiation piece arranged opposite to the fixed seat in the first direction, and a first sealing piece is connected between the radiation piece and the cylinder body;

the radiation part is arranged on one side of the fixed seat in the first direction, and the fixed seat, the cylinder body, the first sealing part and the radiation part enclose a closed cavity, or the radiation part is arranged on both sides of the fixed seat in the first direction, and the two radiation parts, the cylinder body and the first sealing part enclose a closed cavity;

defining an initial distance between the fixed seat and the radiation piece as a first distance, wherein the electromagnetic transducer further comprises a tension structure which drives the radiation piece to move towards a direction close to the fixed seat when the distance between the fixed seat and the radiation piece is greater than the first distance and/or drives the radiation piece to move towards a direction far away from the fixed seat when the distance between the fixed seat and the radiation piece is less than the first distance;

each radiation piece is fixedly provided with an armature towards one side of the fixed seat, each side of the fixed seat towards the radiation piece is fixedly provided with an excitation structure, each excitation structure is provided with an E-shaped structure or is integrally in an E-shaped structure, an opening of each E-shaped structure faces the armature, each E-shaped structure is formed by a base, a first protruding part, a second protruding part and a third protruding part, the first protruding parts, the second protruding parts and the third protruding parts are positioned on the base and are sequentially arranged at intervals, a driving coil is wound on each second protruding part, and the first direction is perpendicular to the coil plane of the driving coil; the electromagnetic transducer also comprises K permanent magnets fixedly connected with the excitation structure or the armature, wherein K is more than or equal to 1, and the K permanent magnets are symmetrically distributed around the axis of the E-shaped structure;

the first magnetic force line is defined as the magnetic force line generated when the driving coil is electrified, the two magnetic poles of the permanent magnets are defined to be positioned at the two ends of the permanent magnets in the height direction, each permanent magnet is arranged on the path through which the first magnetic force line passes, and the height direction of each permanent magnet is parallel to the first magnetic force line passing through the permanent magnet.

According to the principle that like poles repel and opposite poles attract, the armature can move towards the direction close to the excitation structure under the action of electromagnetic force, and the tension structure generates reaction force after being compressed to drive the radiation piece to move towards the direction far away from the fixed seat, so that the armature can drive the radiation piece to reciprocate under the action of the electromagnetic force and the tension of the tension structure under the action of an alternating magnetic field to generate vibration. In the present invention, the permanent magnet may provide a bias magnetic field to eliminate the frequency doubling effect. The addition of the permanent magnet enables the coil current to be free from establishing a direct current bias magnetic field, namely only the driving coil is required to provide an alternating current magnetic field, so that the transduction link is reduced, the number of turns of the electromagnet of the transducer is greatly reduced, the loss of the transducer is reduced, and the transduction efficiency is improved. In the invention, a permanent magnet embedded in a magnetic circuit is used for generating a constant bias magnetic field, an alternating current coil is used for generating an alternating driving magnetic field, the constant bias magnetic field and the alternating driving magnetic field are superposed to form an alternating magnetic field containing direct current bias, under the action of the alternating magnetic field, dynamic electromagnetic force is generated between an excitation structure and an armature, and then a radiation piece is excited to vibrate in a reciprocating manner in a first direction, so that sound waves are generated in a medium (such as water) where a transducer is located and radiate outwards. The mixed excitation mode is adopted to effectively improve the output harmonic problem and the performance evaluation problem under the conventional frequency multiplication excitation.

Furthermore, a first area is defined to be composed of an area formed by contour lines of the outer wall surface of the excitation structure, an area formed by contour lines of the outer wall surface of the armature and a gap area between the excitation structure and the armature, the K permanent magnets are all located in the first area, and at least one end face of each permanent magnet is located at the edge of the gap between the excitation structure and the armature.

According to the invention, through the arrangement, the permanent magnet is only affected by the unavoidable air gap magnetic resistance, and the leakage magnetic resistance is reduced, so that the air magnetic resistance is reduced as far as possible, the problem that the size of the permanent magnet is increased due to large magnetic field loss is avoided, the whole weight and the size of the device are reduced as far as possible, and the requirements of underwater work can be met.

Further, a second direction is defined as the length direction of the armature, and two grooves formed by the E-shaped structure are respectively a first groove and a second groove;

the K permanent magnets include: at least 1 first permanent magnet, and/or at least 1 second permanent magnet, and/or the same number of third permanent magnets and fourth permanent magnets, and/or the same number of fifth permanent magnets and sixth permanent magnets, and/or the same number of seventh permanent magnets and eighth permanent magnets;

the first permanent magnet penetrates through the second convex part in the second direction;

the second permanent magnet is positioned on the end face, facing the armature, of the second convex part;

the third permanent magnet and the fourth permanent magnet are symmetrically distributed about the axis of the E-shaped structure and penetrate through the first convex part and the third convex part in the second direction respectively;

the fifth permanent magnet and the sixth permanent magnet are symmetrically distributed about the axis of the E-shaped structure and are respectively positioned on the end face, facing the armature, of the first bulge part and on the end face, facing the armature, of the third bulge part;

the seventh permanent magnet and the eighth permanent magnet are symmetrically distributed about the axis of the E-shaped structure and penetrate through the base in the first direction respectively, one end face of the seventh permanent magnet in the first direction is located at the edge of the first groove, and one end face of the eighth permanent magnet in the first direction is located at the edge of the second groove.

Further, the first seal is an annular elastic seal; the inner side and the outer side of the first sealing element are respectively and correspondingly fixedly connected with the radiation element and the cylinder body; the electromagnetic transducer also comprises at least three springs which are arranged along the circumferential direction of the radiation piece at intervals, and two ends of each spring are fixedly connected with the radiation piece and the fixed seat respectively; the first sealing element and the spring form the tension structure.

In a preferred embodiment, the spring is a helical compression spring.

Furthermore, a first annular flange is arranged on the end face of the cylinder in the first direction, and the electromagnetic transducer further comprises a second annular flange and a third annular flange;

a sunken step is formed in the periphery of the radiation piece, and the part, close to the inner side, of the first sealing piece is clamped between the sunken step and the second annular flange plate and is fixedly connected with the sunken step and the second annular flange plate;

and the part of the first sealing element close to the outer side is clamped between the first annular flange plate and the third annular flange plate and is fixedly connected with the first annular flange plate and the third annular flange plate.

Furthermore, the radiation member is a film radiation member, and the film radiation member forms a tension structure;

the film type radiation part is of an integrated structure formed by connecting a cylindrical part and a circular ring part positioned on the outer side of the cylindrical part, and the axial direction of the cylindrical part and the axial direction of the circular ring part are overlapped with the axial direction of the cylinder body; the height of the cylindrical part is greater than that of the circular part; the maximum size of the film type radiation piece in the axial direction of the cylinder body is not more than half of the outer diameter of the circular ring part;

the end face, facing the fixed seat, of the cylindrical part is fixedly provided with the armature;

the film type electromagnetic transducer further comprises M first fastening pieces which are arranged along the circumference of the film type radiation piece at intervals and fixedly connect the edge part of the film type radiation piece with the cylinder, wherein M is more than or equal to 3.

In a preferred embodiment, the material of the membrane type radiation member is any one of titanium alloy, stainless steel and 40 CrNiMoA.

According to the principle that like poles repel and opposite poles attract, the armature is acted by electromagnetic force, and the membrane radiation piece is acted by tension of the membrane radiation piece, so that the armature drives the membrane radiation piece to reciprocate under the action of the alternating magnetic field and the action of the electromagnetic force and the tension of the membrane radiation piece to generate vibration. The membrane type radiation member is fixedly connected with the barrel through the first fastening piece, so that outer edge fixing constraint can be provided for membrane type radiation member vibration, namely vibration displacement of the outer edge is zero. The reinforcement is integral with the membrane radiator and both move up and down simultaneously. Because the height of cylinder portion is greater than the height of ring portion, and armature fixes on the terminal surface of cylinder portion, therefore the film type radiation piece is close to the cylinder portion of its center thicker, and peripheral ring region is thinner, has following benefit like this: (A) under the pushing of the armature, the thicker cylindrical part is in translation in the vibration process, namely, each point of the cylindrical part has the same vibration displacement, so that the volume displacement is increased; (B) the thickness of the cylindrical part is larger, so that the armature is convenient to fix, install and prevent water; (C) providing an inner boundary condition for the film radiator.

Furthermore, a reinforcing piece protruding in the direction away from the fixed seat is arranged on the outer end face of each film type radiation piece, the reinforcing piece is of a symmetrical structure taking the circle center of the outer end face of the film type radiation piece as the center, and the reinforcing piece and the film type radiation piece are fixedly connected or are of an integral structure.

In a preferred embodiment, the thickness of the reinforcement member gradually decreases from a position close to the cylinder axis to a position away from the cylinder axis.

The reinforcing member may be of a rigid construction and may be capable of some degree of bending deformation. The reinforcement can be made of the same material as the membrane type radiator. Because the reinforcing part has certain rigidity, the required rigidity can be obtained by adding the rigidity of the reinforcing part and the rigidity of the film type radiation part body. Because the sum of the volumes of the reinforcing member and the film type radiation member is smaller than the volume of the structure only after the thickness of the film type radiation member is increased, the invention can not only reach the target of high sound source level, but also obviously reduce the whole quality of the transducer.

In the present invention, the central region of the reinforcement is thicker and gradually decreases in thickness in the radial direction toward the outer periphery. The applicant found that, in the research, because the edge of the film type radiation member is fixedly connected with the cylinder body through the first fastening member, namely the edge of the film type radiation member is fixedly restrained, the displacement of the film type radiation member close to the edge is small relative to the center displacement of the outer end surface of the film type radiation member. According to the invention, the thickness of the reinforcing part is gradually reduced from the position close to the axis of the cylinder to the position far away from the axis of the cylinder, so that the thickness of the integral structure formed by the reinforcing part and the film type radiation part can be gradually reduced from the position close to the axis of the cylinder to the position far away from the axis of the cylinder, namely, the thickness of the edge part of the integral structure formed by the reinforcing part and the film type radiation part is reduced, so that the rigidity of the edge part is reduced, the vibration displacement of the edge part during the working of the transducer is increased, a flexible boundary can be provided for the vibration of the film type radiation part, and a larger sound radiation power is obtained.

In a more preferred embodiment, the reinforcing member is an auxiliary film type radiation member, the auxiliary film type radiation member is a rotator structure and has a first circular end face and a second circular end face which are oppositely arranged, and the axis of the auxiliary film type radiation member is coincident with the axis of the cylinder body;

the radius of the first circular end face is smaller than that of the second circular end face; the thickness of the auxiliary film type radiation piece is gradually reduced from the position of the circumference of the first circular end face to the position of the circumference of the second circular end face; the second circular end face is connected with the outer end face of the film type radiation piece, so that the auxiliary film type radiation piece and the film type radiation piece form an integrated structure; the auxiliary film type radiation piece and the film type radiation piece are made of the same material; the sum of the maximum sizes of the film type radiation piece and the auxiliary film type radiation piece in the axial direction of the cylinder body is not more than half of the outer diameter of the circular ring part.

According to the invention, the auxiliary film type radiation member is arranged, so that the thickness of the combined structure of the film type radiation member and the auxiliary film type radiation member serving as the radiation member is gradually reduced along the radial direction, namely the central area of the film is thicker and the edge of the film is thin, the rigidity of the transducer is increased, the thickness of the film is effectively reduced, the weight of the transducer is further reduced, and the transducer is favorable for achieving a high sound source level target.

Further, a second sealing element is connected between the fixed seat and the barrel.

Furthermore, an acceleration sensor for measuring the acceleration of the film type radiation piece in the axial direction of the cylinder body is arranged on the radiation piece.

Further, a temperature sensor is arranged on the excitation structure.

Has the advantages that: the hybrid excitation high-power low-frequency electromagnetic transducer provided by the invention has a series of advantages:

1) after the high-performance permanent magnet is added into the excitation stack, the current of the driving coil only provides an alternating current magnetic field, a bias magnetic field is not required to be established, the number of turns of the electromagnet of the transducer is reduced, the loss of the transducer is reduced, and the efficiency is improved. By reasonably configuring the direct-current bias magnetic field and the alternating-current magnetic field, the electromagnetic force characteristic acting on the radiation piece approaches to a linear function, the transducer is not limited by the nonlinear characteristic under the conventional frequency multiplication excitation, and the analysis modeling and the performance evaluation of the transducer are simplified to a great extent.

2) The electromagnetic transducer is suitable for the equivalent circuit theory in the field of underwater acoustic transducers, and is convenient for designers to perform modeling analysis and evaluate the relevant performance indexes of the transducer.

3) The electromagnetic transducer can effectively reduce the power consumption of the matched power amplifier.

Drawings

FIG. 1 is a schematic view of the internal structure of an electromagnetic transducer of embodiment 1 of the invention;

FIG. 2 is a schematic diagram of the structure of the armature, the excitation structure and the permanent magnet in FIG. 1;

fig. 3(a) and 3(b) are schematic partial perspective structures of the first permanent magnet and the second convex part in fig. 1 in two embodiments;

FIG. 4 is a schematic view of the internal structure of an electromagnetic transducer of embodiment 2 of the invention;

FIG. 5 is a schematic view of the internal structure of an electromagnetic transducer of embodiment 3 of the invention;

FIG. 6 is a schematic view of the structure of the radiating element of FIG. 4;

fig. 7(a) and 7(b) are schematic structural views of an armature, an excitation structure, and a permanent magnet according to embodiment 4 of the present invention;

fig. 8(a) and 8(b) are schematic structural views of an armature, an excitation structure, and a permanent magnet according to embodiment 5 of the present invention;

fig. 9(a) and 9(b) are schematic structural views of an armature, an excitation structure, and a permanent magnet according to embodiment 6 of the present invention;

fig. 10 is a schematic structural view of an armature, an excitation structure, and a permanent magnet of embodiment 7 of the invention;

fig. 11(a) and 11(b) are schematic diagrams of a first permanent magnet according to an embodiment of the present invention in a slicing mode and a slitting mode, respectively;

in the above drawings, 1, an armature, 2, an excitation structure, 21, a first convex portion, 22, a second convex portion, 23, a third convex portion, 24, a base, 251, a first groove, 252, a second groove, 3, a driving coil, 31, a first magnetic line of force, 4, a radiation member, 41, a cylindrical portion, 42, a ring portion, 43, an auxiliary film type radiation member, 43a, a first circular end face, 43b, a second circular end face, 51, a first permanent magnet, 52, a second permanent magnet, 53, a third permanent magnet, 54, a fourth permanent magnet, 55, a fifth permanent magnet, 56, a sixth permanent magnet, 57, a seventh permanent magnet, 58, an eighth permanent magnet, 6, a fixed seat, 71, a first seal, 72, a second seal, 81, a first fastener, 82, a second fastener, 83, a third fastener, 84, a fourth fastener, 9, a watertight cable head, 10, a cylinder, 11. the device comprises a first annular flange plate, 12, a second annular flange plate, 13, a third annular flange plate, 20, a spring, 101, an acceleration sensor, 102 and a temperature sensor.

Detailed Description

Example 1

As shown in fig. 1 to 3, the present invention provides an electromagnetic transducer including a cylinder 10, the cylinder 10 being a rotary body structure. The first direction is defined as a length direction of the cylinder 10. When the transducer of the present application is used in water, the cylinder 10 may be fixed to a hull or a buoy.

The electromagnetic transducer further comprises a fixed seat 6 fixedly connected with the cylinder 10 and a radiation piece 4 arranged opposite to the fixed seat 6 in the first direction, and a first sealing element 71 is connected between the radiation piece 4 and the cylinder 10. In the first direction, the radiation part 4 is arranged on one side of the fixed seat 6, and the fixed seat 6, the cylinder 10, the first sealing part 71 and the radiation part 4 enclose a closed cavity. The shape of the surface of the radiating element 4 is preferably circular or elliptical.

Defining the initial distance between the fixed seat 6 and the radiating element 4 as a first distance, said electromagnetic transducer further comprising a tensioning structure. The tension structure is used for: when the distance between the fixed seat 6 and the radiation part 4 is larger than the first distance, the radiation part 4 is driven to move towards the direction close to the fixed seat 6, and/or when the distance between the fixed seat 6 and the radiation part 4 is smaller than the first distance, the radiation part 4 is driven to move towards the direction far away from the fixed seat 6. The side of the radiation piece 4 facing the fixed seat 6 is fixedly provided with an armature 1. The second direction is defined as the length direction of the armature 1. The tension structure provides a force close to the fixation seat 6 when the distance between the fixation seat 6 and the radiation element 4 is larger than the first distance and/or a force away from the fixation seat 6 when the distance between the fixation seat 6 and the radiation element 4 is smaller than the first distance. The tension structure generates a force in an extension direction when compressed in a longitudinal direction, and generates a force in a compression direction when extended in the longitudinal direction.

The fixed seat 6 is fixedly provided with an excitation structure 2 towards one side of the radiation piece 4, the excitation structure 2 is provided with an E-shaped structure or is integrally of an E-shaped structure, the opening of the E-shaped structure faces the armature 1, the E-shaped structure is formed by a base 24, a first protruding portion 21, a second protruding portion 22 and a third protruding portion 23, the first protruding portion 21, the second protruding portion 22 and the third protruding portion 23 are located on the base 24 and are sequentially arranged at intervals, the driving coil 3 is wound on the second protruding portion 22, and the first direction is perpendicular to the coil plane of the driving coil 3.

The armature 1 can be fixed in the central position of the radiator 4, always facing the E-shaped excitation structure 2. The E-shaped excitation structure 2 can be fixed at the central position of the fixed seat 6 and forms a magnetic circuit together with the armature 1 and the air gap. The drive coil 3 is preferably an ac drive coil that provides an ac magnetic field. The alternating current driving coil is wound by a high-temperature enameled wire, can be electrified with short-time heavy current and is fixed on the E-shaped excitation structure 2.

The electromagnetic transducer also comprises K permanent magnets fixedly connected with the excitation structure 2 or the armature 1, wherein K is more than or equal to 1, and the shape defined by the K permanent magnets is symmetrically distributed around the axis of the E-shaped structure. The first magnetic force lines 31 are defined as magnetic force lines generated when the driving coils 3 are electrified, two magnetic poles of the permanent magnets are defined to be positioned at two ends of the permanent magnets in the height direction, each permanent magnet is arranged on a path through which the first magnetic force lines 31 pass, and the height direction of each permanent magnet is parallel to the first magnetic force lines 31 passing through the permanent magnets. The first area is defined to be composed of an area formed by the contour lines of the outer wall surfaces of the excitation structure 2, an area formed by the contour lines of the outer wall surfaces of the armature 1 and a gap area between the excitation structure 2 and the armature 1. In the present application, the portions between the surface of the excitation structure 2 facing the armature 1 and the surface of the armature 1 facing the excitation structure 2 both belong to the gap between the excitation structure 2 and the armature 1, i.e., the first groove 251 and the second groove 252 also belong to the gap between the excitation structure 2 and the armature 1.

For example, in fig. 2, a rectangular parallelepiped surrounding the armature 1 and the field structure 2 is a first region. K permanent magnets are located in the first area, at least one end face of each permanent magnet is located at the edge of a gap between the excitation structure 2 and the armature 1, and each permanent magnet is arranged towards the gap between the excitation structure 2 and the armature 1. The two grooves formed by defining the E-shaped structure are the first groove 251 and the second groove 252, respectively. The gap between the excitation structure 2 and the armature 1 includes a first groove 251 and a second groove 252.

As shown in fig. 2, in the present embodiment, the K permanent magnets are 1 first permanent magnet 51. The first permanent magnet 51 penetrates the second convex portion 22 in the second direction. In the invention, the structure A "penetrates through the structure B, which means that the structure B is composed of parts positioned at two sides of the structure A, the two parts of the structure B are mutually independent, and the structure A is arranged between the two parts; "through" may also mean that the a-structure is disposed in a via or through hole that runs through the B-structure. Two end faces of the first permanent magnet 51 respectively face the first groove 251 and the second groove 252 in the second direction, and are respectively located at the edges of the first groove 251 and the second groove 252. More preferably, the first permanent magnet 51 and the second convex portion 22 have the same sectional area.

As shown in fig. 3(a) and 3(b), the permanent magnet 51 may be formed by stacking sheet-shaped permanent magnets to reduce eddy current loss. The cutting patterns of fig. 3(a) and 3(b) are possible, and can be understood as different "putting" directions of the permanent magnet of fig. 11.

The first sealing member 71 is an annular elastic sealing member for sealing and waterproofing, and the material may be rubber having a watertight function. And the outer circumference is fixedly connected with the cylinder 10 by a third fastening member 83. When the radiation member 4 reciprocates in the first direction, the first seal member 71 is extended or compressed accordingly.

The electromagnetic transducer further comprises at least three springs 20 arranged circumferentially spaced along the radiator 4. Two ends of the spring 20 are respectively fixedly connected with the radiation piece 4 and the fixed seat 6; the first seal 71 and the spring 20 constitute the tension structure. Preferably, the spring 20 is a helical compression spring, the helical compression spring 20 providing stiffness. The springs 20 may be arranged evenly circumferentially on the surface of the fixing base 6 facing the armature 1.

The end face of the cylinder 10 in the first direction is provided with a first annular flange 11, and the electromagnetic transducer further comprises a second annular flange 12 and a third annular flange 13.

And notches with rectangular longitudinal sections can be formed in the periphery of the radiation piece 4 to form sunken steps.

The portion of the first sealing element 71 near the inside is clamped between the step and the second annular flange 12 and can be fixedly connected to the step and the second annular flange 12 by means of the second fastening element 82, and thus to the radiator element 4.

The portion of the first seal 71 near the outside is sandwiched between the first ring flange 11 and the third ring flange 13, and is fixedly connected to the first ring flange 11 and the third ring flange 13 by the third fastening member 83.

The first sealing element 71 is fixedly connected to the cylinder 10 via a first annular flange 11. The first annular flange 11 may be of annular configuration. In a preferred embodiment, a first annular flange 11 is mounted at each opening location of the cartridge body 10. The shape of the surface of the radiating element 4 is preferably circular or elliptical.

And a second sealing element 72 is connected between the fixed seat 6 and the cylinder 10 and is used for sealing and preventing water. The fourth fastener 84 passes through the fixing base 6, the second sealing element 72 and the cylinder 10 in sequence, so that the three are fixedly connected.

The second fastener 82, the third fastener 83, and the fourth fastener 84 may be attachment bolts.

The radiation member 4 is provided with an acceleration sensor 101 for measuring the acceleration of the film radiation member in the axial direction of the cylinder. The excitation structure 2 is provided with a temperature sensor 102. The acceleration sensor 101 is used to measure the vibrational displacement of the radiating element 4. The temperature sensor 102 is used to monitor the temperature change of the transducer core.

The fixing base 6 is used for fixing the excitation structure 2 and the spring 20, is connected with the radiation member 4 through the spring 20, and is connected with the cylinder 10 through the fourth fastening member 84. The piston-type radiating element 4 may be a cylinder. The piston-type radiation element 4 is connected to the holder 6 via a spring 20 and is axially (also considered to be a direction coinciding or parallel with the first direction) reciprocatingly movable.

The permanent magnet is used for providing a bias magnetic field to eliminate frequency doubling transduction characteristics, and the shape of the permanent magnet can be a cuboid. The cross section area of the permanent magnet perpendicular to the magnetizing direction can be consistent with the cross section area of the magnetic circuit perpendicular to the magnetizing direction. The permanent magnets may be sliced or slit to reduce eddy current losses. In the present application, the permanent magnet is not arranged so long as the magnetization direction is parallel to the magnetic lines of force generated by the ac coil, and the air reluctance is reduced as much as possible in addition to the unavoidable air gap reluctance.

Fig. 11(a) and 11(b) are schematic diagrams of a first permanent magnet slicing method and a slitting method, respectively, according to an embodiment of the present invention, where solid arrows indicate a permanent magnet magnetizing direction, and dotted lines indicate an eddy current effect when an exciter stack is energized.

The cylinder 10 has a watertight cable head 9 (preferably on the side wall). The watertight cable head 9 is electrically connected to the ac driving coil 4 through a wire.

The armature 1 can be formed by laminating I-shaped silicon steel sheets so as to reduce eddy current loss. The E-shaped excitation structure 2 can be formed by laminating E-shaped silicon steel sheets to reduce eddy current loss. The material of the radiant member 4 can be any one of aluminum, stainless steel, high-strength alloy steel and the like. The spring 20 material may be a silicon manganese alloy. The permanent magnet material is any one of neodymium iron boron and samarium cobalt.

When the transducer works, the permanent magnet provides a bias magnetic field, the magnetic field provides a static bias working point for the electromagnetic transducer, alternating current is simultaneously introduced into the alternating current driving coil 4 to excite the alternating current magnetic field to be superposed on the constant bias magnetic field, and the two magnetic fields flow in a closed magnetic circuit formed by the E-shaped excitation structure 2, the armature 1 and the air gap. In this case, the field structure 2 is equivalent to an electromagnet, and the armature 1 is subjected to an electromagnetic force directed from the armature 1 to the field structure 2. The alternating magnetic field only affects the magnitude of the electromagnetic force acting on the armature 1, and does not change the direction of the electromagnetic force. The radiation member 4 is integral with the armature 1, and the radiation member 4 reciprocates in a first direction under the combined action of the spring 20 and the armature 1, thereby radiating sound waves outwards.

In this application, for further reducing the transduction link, reduce the loss of transducer, raise the efficiency, direct embedding permanent magnet is in order to provide bias magnetic field cooperation alternating current excitation coil in the excitation of transducer pile magnetic circuit. Under the combined action of the permanent magnet and the alternating current excitation, the harmonic distortion rate of the sound wave output by the transducer is reduced, the electromagnetic force can be approximated to a linear function of alternating current and displacement alternating variable, and the performance evaluation of the transducer is simplified by the linearization of the transduction mechanism. The permanent magnets are used to provide a bias field to eliminate the frequency doubling effect and are sliced or lanced to reduce eddy current losses. The addition of the permanent magnet enables the coil current not to need to establish a bias magnetic field any more, but only needs to provide an alternating magnetic field, further reduces the transduction link, greatly reduces the number of turns of the electromagnet of the transducer, reduces the loss of the transducer and improves the transduction efficiency. The permanent magnet is arranged in a closed magnetic circuit formed by the excitation stack, the air gap and the armature and connected with the E-shaped excitation structure, and the permanent magnet has the function of reducing the frequency doubling effect under alternating current excitation. After the permanent magnet is used, the current required to be introduced into the coil of the transducer is reduced, and the power consumption of a matched power amplifier is reduced.

The permanent magnet of the electromagnetic transducer generates a direct-current bias magnetic field in a magnetic circuit, the frequency doubling effect is greatly reduced due to the existence of the direct-current bias magnetic field, the transducer is not limited by the nonlinear characteristic under the conventional frequency doubling excitation, and the analysis modeling and performance evaluation of the transducer are simplified to a great extent. If the nonlinearity caused by factors such as magnetic hysteresis loss, eddy current loss, magnetic saturation, magnetic leakage, edge effect and the like in the transduction process of the electromagnetic transducer is ignored, electromagnetic force exists

Wherein

Is an alternating magnetic flux. If an alternating current with frequency f is directly applied, then

The expression of (2) is approximate to Asin (2 pi ft), and the frequency of the electromagnetic force is 2f, so that the frequency of the obtained displacement waveform is also 2f, which is the origin of frequency doubling effect. After applying a suitable dc bias (setting the permanent magnet) and an ac excitation of frequency f,

is approximately B + Asin (2 π ft), and

at this time, the frequency of the displacement waveform is f, and the frequency doubling effect is greatly reduced by the direct current offset. Further, if the relationship between a and B satisfies that a is much smaller than B, the electromagnetic force can be approximately considered as a linear function of the alternating current and the displacement alternating quantity.

Example 2

As shown in fig. 4, the present embodiment 2 is different from embodiment 1 in that: the radiation pieces 4 are arranged on two sides of the fixed seat 6 in the first direction, the two radiation pieces 4, the cylinder 10 and the first sealing element 71 form a closed cavity, an armature 1 is fixedly arranged on one side, facing the fixed seat 6, of each radiation piece 4, and an excitation structure 2 is fixedly arranged on each side, facing the radiation pieces 4, of the fixed seat 6; at least three springs 20 arranged along the circumferential direction of the radiation member 4 at intervals are arranged between each radiation member 4 and the corresponding side of the fixed seat 6. Two ends of the spring 20 are respectively fixedly connected with corresponding sides of the radiation piece 4 and the fixed seat 6. The fixed seat 6 divides the closed cavity into two regions, the excitation structure 2 in each region is arranged opposite to the armature 1, and the opening of the E-shaped structure in each region is arranged towards the armature 1.

Fixing base 6 and barrel 10 internal wall fixed connection (for example welding) of electromagnetic transducer in this embodiment, fixing base 6 will the watertight space divide into two subspaces along the adjacent setting of first direction, fixing base 6 all is fixed on two terminal surfaces on the first direction and is provided with excitation structure 2, excitation structure 2 is last around being equipped with drive coil 3, cylinder portion 41 is fixed armature 1 that is provided with on the terminal surface towards fixing base 6. The armature 1 and the excitation structure 2 which are positioned in the same subspace are oppositely arranged in the first direction.

Preferably, the electromagnetic transducer takes the fixed seat 6 as a central axis, the watertight cable head 9 is removed and placed outside the upper side of the fixed seat 6, and the upper side and the lower side of the fixed seat 6 have completely identical structures. The electromagnetic transducer has the characteristic of double-sided radiation, and the sound source level of the transducer is effectively improved. The rest of this example is the same as example 1.

Example 3

The present embodiment 3 differs from embodiment 1 in that: the radiation member 4 is a film radiation member, and the film radiation member forms a tension structure; the film type radiation part is an integral structure formed by mutually connecting a cylindrical part 41 and a circular ring part 42 positioned outside the cylindrical part 41, and the axial direction of the cylindrical part 41 and the axial direction of the circular ring part 42 are superposed with the axial direction of the cylinder 10; the height of the cylindrical part 41 is greater than that of the circular part 42; the maximum size of the film type radiation piece in the axial direction of the cylinder 10 is not more than half of the outer diameter of the circular ring part 42; the end face, facing the fixed seat 6, of the cylindrical part 41 is fixedly provided with the armature 1; the outer end face of each film type radiation piece is provided with a reinforcing piece protruding towards the direction far away from the fixed seat 6, the reinforcing piece is of a symmetrical structure taking the circle center of the outer end face of the film type radiation piece as the center, and the reinforcing piece and the film type radiation piece are fixedly connected or are of an integral structure.

The material of the radiant part 4 is any one of titanium alloy, stainless steel and 40 CrNiMoA.

The film type electromagnetic transducer further comprises M first fasteners 81 which are arranged along the circumference of the film type radiation piece at intervals and fixedly connect the edge part of the film type radiation piece with the cylinder body (10), wherein M is more than or equal to 3. The first fastener 81 may be a connection bolt.

In a preferred embodiment, the thickness of the reinforcement member gradually decreases from a position close to the axis of the can 10 to a position away from the axis of the can 10.

In a more preferred embodiment, as shown in fig. 5 to 6, the reinforcing member is an auxiliary film type radiation member 43, the auxiliary film type radiation member 43 is of a rotating body structure and has a first circular end surface 43a and a second circular end surface 43b which are oppositely arranged, and the axis of the auxiliary film type radiation member 43 is coincident with the axis of the cylinder 10; the radius of the first circular end surface 43a is smaller than that of the second circular end surface 43 b; the thickness of the auxiliary film type radiation member 43 is gradually reduced from the position of the circumference of the first circular end surface 43a to the position of the circumference of the second circular end surface 43 b; the second circular end surface 43b is connected with the outer end surface of the film type radiation piece, so that the auxiliary film type radiation piece 43 and the film type radiation piece form an integral structure; the auxiliary film type radiation piece 43 and the film type radiation piece are made of the same material; the sum of the maximum sizes of the film radiation member and the auxiliary film radiation member 43 in the axial direction of the cylinder 10 is not more than half of the outer diameter of the circular ring part 42.

The reinforcing member is an auxiliary film type radiation member 43, the auxiliary film type radiation member 43 is of a rotator structure and is provided with a first circular end surface 43a and a second circular end surface 43b which are oppositely arranged, and the axis of the auxiliary film type radiation member 43 is superposed with the axis of the cylinder 10; the radius of the first circular end surface 43a is smaller than that of the second circular end surface 43 b; the thickness of the auxiliary film type radiation member 43 is gradually reduced from the position of the circumference of the first circular end surface 43a to the position of the circumference of the second circular end surface 43 b; the second circular end surface 43b is connected (attached to) the outer end surface of the film type radiation member, so that the auxiliary film type radiation member 43 and the film type radiation member form an integral structure. The auxiliary film radiator 43 and the film radiator are preferably made of the same material. The sum of the maximum sizes of the film radiation member and the auxiliary film radiation member 43 in the axial direction of the cylinder 10 is not more than half of the outer diameter of the circular ring part 42. The auxiliary film type radiator 43 may be in the form of a circular truncated cone, or may be in the form similar to a circular truncated cone, i.e., the side of the longitudinal section thereof is arc-shaped. The thickness of the auxiliary film type radiation member 43 is the dimension of the auxiliary film type radiation member 43 in the axial direction of the cylinder 10. The cylinder 10 axis is perpendicular to the first circular end face 43a and perpendicular to the second circular end face 43 b.

In the embodiment, the center area of the membrane is thicker, the edge of the membrane is thin, the thickness of the membrane is gradually reduced along the radial direction, and the radiation piece adopts the variable-thickness membrane, so that the rigidity of the transducer is improved, the thickness of the membrane is effectively reduced, the weight of the transducer is further reduced, and the transducer is favorable for achieving a high sound source level target.

The radiator 4 of the electromagnetic transducer is a film tension structure. The radiation part 4 does not need the spiral compression spring 20 to provide rigidity, has light weight, large deformation after stress, larger volume compared with a piston type radiation part, larger volume displacement during working and easier realization of a high sound source level target.

The membrane type radiation part is formed into an integral structure by mutually connecting a cylindrical part 41 and a circular ring part 42 positioned outside the cylindrical part 41, and the axial direction of the cylindrical part 41 and the axial direction of the circular ring part 42 are superposed with the axial direction of the cylinder 10; the height of the cylindrical portion 41 is greater than the height of the circular portion 42. The membrane type radiation piece has the advantages that the inner circular area is thicker (the height of the cylindrical part 41 is larger), the peripheral circular area is thinner (the height of the circular part 42 is smaller), and the functions of the membrane type radiation piece comprise: for mounting a block of magnetically conductive material (i.e. armature 1); providing an inner boundary condition for the toroidal membrane to vibrate.

The first fastener 81 may be a connection bolt. The tie bolts are used to secure the membrane radiator and the housing together, forming a sealed space to be water tight, while providing an outer edge securement constraint for membrane vibration. The first fasteners 81 may be evenly circumferentially disposed about the outer end face of the membrane radiator.

A first seal 71 may be placed at the connection of the membrane radiator to the cylinder 10 for sealing against water. In a preferred embodiment, a first annular flange 11 is mounted at each opening location of the cartridge body 10. The first fastening member 81 passes through the edge portion of the outer end face of the membrane type radiator, the first sealing member 71 and the first annular flange 11 in this order, thereby fixedly connecting the three.

The first and second seals 71 and 72 may be made of an annular elastic material such as rubber. The seal is used to seal the transducer against water.

The membrane type radiation piece is used as a vibration part, and the membrane structure is used as a tension structure form, so that the membrane type radiation piece has the advantages of small rigidity, light weight and large deformation after stress. Therefore, when the electromagnetic radiation-proof energy converter is applied to the electromagnetic energy converter, the low-frequency high-power radiation of the energy converter can be effectively realized. In order to ensure the normal work of the transducer in water, a gas or liquid pressure compensation device can be connected outside the transducer to change the compensation pressure inside the transducer, so that the invention is suitable for the work in deeper water.

In the present invention, a driving current (e.g. an alternating current) with a given frequency is applied to the driving coil 3, and an alternating magnetic field is generated by the magnetic effect of the current, and the alternating magnetic field further generates an alternating electromagnetic force on the film type radiation member, and under the action of the electromagnetic force, the vibration of the film type radiation member is excited, so that sound waves are generated in the medium and radiated outwards. The magnetic field passes through the excitation structure, the armature 1 and the air gap to form a closed magnetic circuit. In this case, the field stack is equivalent to a magnet, and the magnetic field strength at the air gap is enhanced by the front and rear magnetic conductive materials. According to the principle that like poles repel and opposite poles attract, the armature 1 and the excitation structure 2 are acted by electromagnetic force; meanwhile, the film type radiation piece is under the action of self tension, and the armature iron drives the film type radiation piece to reciprocate under the action of electromagnetic force and self tension under the action of an alternating magnetic field by controlling the driving current to generate vibration. The film type radiation member is used as a tension structure form, so that the film type electromagnetic transducer does not need an additional compression spring. As the radiation piece, the membrane type radiation piece has large deformation after being stressed and large radiation area, and is beneficial to improving the sound source level. In addition, the surface of the film type radiation part is provided with an acceleration sensor, and the inside of the film type radiation part is provided with a pressure sensor and a temperature sensor, so that the stable and reliable use of the transducer is ensured. Under the action of an alternating magnetic field generated by the driving coil 3, the armature 1 vibrates upwards and downwards along the axial direction of the cylinder 10 under the combined action of alternating electromagnetic force and tension of the film type radiation member, so that the vibration of the film type radiation member is excited, and sound waves are radiated outwards. By adopting the membrane structure, the volume of the radiation element is increased, and further the volume displacement is increased, thereby realizing the high-power sound wave emission.

The direction of the force between the armature and the excitation structure 2 can be kept constant, in this structure, the attraction force exists between the armature and the excitation structure, the back vibration of the armature is caused by the fact that the electromagnetic force is reduced along with the reduction of the current in one period, and the tension of the membrane pulls the armature back.

The radiating member is largely deformed by vibration because the radiating member is formed as a "membrane". The same force is applied and the deformation is certainly large for a thin thickness. However, the thickness is reduced, the deformation is large, and simultaneously, the film is required to have large yield strength and tensile strength, so that plastic deformation is avoided when vibration occurs. These titanium alloys, stainless steels, and high strength alloy steels have high yield and tensile strengths and can be made into "membrane" type radiating elements.

Example 4

As shown in fig. 7(a) and 7(b), the present embodiment 5 differs from embodiment 1 in that: the K permanent magnets consist of 1 third permanent magnet 53, 1 fourth permanent magnet 54.

The third permanent magnet 53 and the fourth permanent magnet 54 are symmetrically distributed about the axis of the E-shaped structure and penetrate through the first convex portion 21 and the third convex portion 23 in the second direction, respectively. One end face of the third permanent magnet 53 and one end face of the fourth permanent magnet 54 respectively face the first groove 251 and the second groove 252 in the second direction, and are respectively located at the edge of the first groove 251 and the edge of the second groove 252. Preferably, the first convex portion 21 is formed of portions located on both sides of the third permanent magnet 51 in the first direction, and the third convex portion 23 is formed of portions located on both sides of the fourth permanent magnet 54 in the first direction. More preferably, the third permanent magnet 53 has the same cross-sectional area as the first convex portion 21, and the fourth permanent magnet 54 has the same cross-sectional area as the third convex portion 23.

The N pole of the third permanent magnet 53 is positioned at one end of the third permanent magnet 53 close to the armature 1, and the N pole of the fourth permanent magnet 54 is positioned at one end of the fourth permanent magnet 54 close to the armature 1; or the N pole of the third permanent magnet 53 is located at the end of the third permanent magnet 53 away from the armature 1, and the N pole of the fourth permanent magnet 54 is located at the end of the fourth permanent magnet 54 away from the armature 1.

Example 5

As shown in fig. 8(a) and 8(b), the present embodiment 5 differs from embodiment 1 in that: the K permanent magnets consist of 1 second permanent magnet 52, 1 fifth permanent magnet 55, and 1 sixth permanent magnet 56.

The second permanent magnet 52 is located on the end face of the second projecting portion 22 facing the armature 1. The second permanent magnet 52 may be disposed in a second direction.

The fifth permanent magnet 55 and the sixth permanent magnet 56 are symmetrically distributed about the axis of the E-shaped structure and are respectively located on the end face of the first convex portion 21 facing the armature 1 and the end face of the third convex portion 23 facing the armature 1. The fifth permanent magnet 55 and the sixth permanent magnet 56 may be disposed along the second direction.

Preferably, the fifth permanent magnet 55 has the same cross-sectional area as the first convex portion 21, and the sixth permanent magnet 56 has the same cross-sectional area as the third convex portion 23.

The N pole of the second permanent magnet 52 is positioned at one end of the second permanent magnet 52 far away from the armature 1, the N pole of the fifth permanent magnet 55 is positioned at one end of the fifth permanent magnet 55 close to the armature 1, and the N pole of the sixth permanent magnet 56 is positioned at one end of the sixth permanent magnet 56 close to the armature 1; or the N pole of the second permanent magnet 52 is located at one end of the second permanent magnet 52 close to the armature 1, the N pole of the fifth permanent magnet 55 is located at one end of the fifth permanent magnet 55 far from the armature 1, and the N pole of the sixth permanent magnet 56 is located at one end of the sixth permanent magnet 56 far from the armature 1.

Example 6

As shown in fig. 9(a) and 9(b), the present embodiment 6 differs from embodiment 1 in that: the K permanent magnets are composed of 1 seventh permanent magnet 57 and 1 eighth permanent magnet 58.

The seventh permanent magnet 57 and the eighth permanent magnet 58 are symmetrically distributed about the axis of the E-shaped structure and penetrate the base 24 in the first direction respectively. One end face of the seventh permanent magnet 57 faces the first groove 251 in the first direction and is located at the edge of the first groove 251, and one end face of the eighth permanent magnet 58 faces the second groove 252 in the first direction and is located at the edge of the second groove 252.

Preferably, the base 24 is constituted by a portion located on the side of the seventh permanent magnet 57 away from the eighth permanent magnet 58 in the second direction, a portion located between the seventh permanent magnet 57 and the eighth permanent magnet 58, and a portion located on the side of the eighth permanent magnet 58 away from the seventh permanent magnet 57 in the second direction. More preferably, the base 24, the seventh permanent magnet 57, and the eighth permanent magnet 58 are equal in longitudinal sectional area.

The S pole of the seventh permanent magnet 57 is located at one end of the seventh permanent magnet 57 close to the eighth permanent magnet 58, and the S pole of the eighth permanent magnet 58 is located at one end of the eighth permanent magnet 58 close to the seventh permanent magnet 57; or the S-pole of the seventh permanent magnet 57 is located at the end of the seventh permanent magnet 57 away from the eighth permanent magnet 58, and the S-pole of the eighth permanent magnet 58 is located at the end of the eighth permanent magnet 58 away from the seventh permanent magnet 57.

Example 7

As shown in fig. 10, the present embodiment 7 differs from embodiment 1 in that: the K permanent magnets consist of 1 ninth permanent magnet 591, 1 tenth permanent magnet 592 and 1 eleventh permanent magnet 593. The K permanent magnets are all fixed on one side of the armature 1 facing the excitation structure 2. The ninth permanent magnet 591, the tenth permanent magnet 592 and the eleventh permanent magnet 593 are respectively and correspondingly oriented towards the first convex portion 21, the second convex portion 22 and the third convex portion 23.

The N pole of the ninth permanent magnet 591 is located at one end of the ninth permanent magnet 591 far away from the excitation structure 2, the N pole of the tenth permanent magnet 592 is located at one end of the tenth permanent magnet 592 close to the excitation structure 2, and the N pole of the eleventh permanent magnet 593 is located at one end of the eleventh permanent magnet 593 far away from the excitation structure 2; the N pole of the ninth permanent magnet 591 is located at one end of the ninth permanent magnet 591 close to the excitation structure 2, the N pole of the tenth permanent magnet 592 is located at one end of the tenth permanent magnet 592 far from the excitation structure 2, and the N pole of the eleventh permanent magnet 593 is located at one end of the eleventh permanent magnet 593 close to the excitation structure 2.

The embodiment only shows an embodiment in which the permanent magnet is disposed in the armature, and those skilled in the art may also refer to other embodiments to dispose the permanent magnet at other positions of the armature 1, and need to satisfy the condition that "each permanent magnet is disposed on the path through which the first magnetic force lines 31 pass, and the height direction of each permanent magnet is parallel to the first magnetic force lines 31 passing through the permanent magnet".

It should be noted that, in the present specification, the embodiments are all described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments may be referred to each other.

The embodiments of the present invention have been described in detail, but the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention should be covered by the present patent. After reading this disclosure, modifications of various equivalent forms of the present invention by those skilled in the art will fall within the scope of the present application, as defined in the appended claims. The embodiments and features of the embodiments of the present invention may be combined with each other without conflict.

Claims (12)

1. An electromagnetic transducer comprising a cylinder (10), said cylinder (10) being of a rotary structure defining a first direction being the length direction of the cylinder (10), characterized in that:

the electromagnetic transducer further comprises a fixed seat (6) fixedly connected with the cylinder (10) and a radiation piece (4) arranged opposite to the fixed seat (6) in the first direction, and a first sealing element (71) is connected between the radiation piece (4) and the cylinder (10);

the radiation part (4) is arranged on one side of the fixed seat (6) in the first direction, and the fixed seat (6), the cylinder (10), the first sealing element (71) and the radiation part (4) enclose a closed cavity, or the radiation part (4) is arranged on both sides of the fixed seat (6) in the first direction, and the two radiation parts (4), the cylinder (10) and the first sealing element (71) enclose a closed cavity;

defining the initial distance between the fixed seat (6) and the radiation piece (4) as a first distance, wherein the electromagnetic transducer further comprises a tension structure which drives the radiation piece (4) to move towards the direction close to the fixed seat (6) when the distance between the fixed seat (6) and the radiation piece (4) is greater than the first distance and/or drives the radiation piece (4) to move towards the direction far away from the fixed seat (6) when the distance between the fixed seat (6) and the radiation piece (4) is less than the first distance;

each radiation piece (4) is fixedly provided with an armature (1) towards one side of the fixed seat (6), the fixed seat (6) is fixedly provided with an excitation structure (2) towards each side of the radiation piece (4), the excitation structure (2) is provided with an E-shaped structure or is integrally in the E-shaped structure, the opening of the E-shaped structure faces the armature (1), the E-shaped structure is formed by a base (24), a first protruding part (21), a second protruding part (22) and a third protruding part (23), the first protruding part (21), the second protruding part (22) and the third protruding part are sequentially arranged on the base (24) at intervals, a driving coil (3) is wound on the second protruding part (22), and the first direction is perpendicular to the coil plane of the driving coil (3);

the electromagnetic transducer also comprises K permanent magnets fixedly connected with the excitation structure (2), wherein K is more than or equal to 1, and the K permanent magnets are symmetrically distributed around the axis of the E-shaped structure;

defining a first magnetic line (31) as a magnetic line generated when the driving coil (3) is electrified, defining two magnetic poles of the permanent magnets to be positioned at two ends of the permanent magnets in the height direction, wherein each permanent magnet is arranged on a path through which the first magnetic line (31) passes, and the height direction of each permanent magnet is parallel to the first magnetic line (31) passing through the permanent magnet;

defining a first area consisting of an area surrounded by an outer wall contour line of an excitation structure (2), an area surrounded by an outer wall contour line of an armature (1) and a gap area between the excitation structure (2) and the armature (1), wherein K permanent magnets are all positioned in the first area, and at least one end surface of each permanent magnet is positioned at the edge of the gap between the excitation structure (2) and the armature (1);

the second direction is defined as the length direction of the armature (1), and two grooves formed by the E-shaped structure are respectively a first groove (251) and a second groove (252);

the K permanent magnets include: at least 1 first permanent magnet (51), and/or the same number of third permanent magnets (53) and fourth permanent magnets (54), and/or the same number of seventh permanent magnets (57) and eighth permanent magnets (58);

the first permanent magnet (51) is disposed in a through hole penetrating the second convex portion (22) so as to penetrate the second convex portion (22) in the second direction;

the third permanent magnet (53) and the fourth permanent magnet (54) are symmetrically distributed about the axis of the E-shaped structure, the third permanent magnet (53) is arranged in a through hole penetrating through the first convex part (21) so as to penetrate through the first convex part (21) in the second direction, and the fourth permanent magnet (54) is arranged in a through hole penetrating through the third convex part (23) so as to penetrate through the third convex part (23) in the second direction;

the seventh permanent magnet (57) and the eighth permanent magnet (58) are symmetrically distributed about an axis of the E-shaped structure, the seventh permanent magnet (57) is arranged in a through hole penetrating through the base (24) so as to penetrate through the base (24) in the first direction, the eighth permanent magnet (58) is arranged in a through hole penetrating through the base (24) so as to penetrate through the base (24) in the first direction, one end face of the seventh permanent magnet (57) in the first direction is located at the edge of the first groove (251), and one end face of the eighth permanent magnet (58) in the first direction is located at the edge of the second groove (252).

2. An electromagnetic transducer according to claim 1, wherein:

the first seal (71) is an annular elastic seal; the inner side and the outer side of the first sealing element (71) are respectively and correspondingly fixedly connected with the radiation element (4) and the cylinder body (10);

the electromagnetic transducer also comprises at least three springs (20) which are arranged along the circumferential direction of the radiation piece (4) at intervals, and two ends of each spring (20) are respectively fixedly connected with the radiation piece (4) and the fixed seat (6);

the first sealing piece (71) and the spring (20) form the tension structure.

3. An electromagnetic transducer according to claim 2, wherein: the spring (20) is a helical compression spring.

4. An electromagnetic transducer according to claim 2, wherein: a first annular flange (11) is arranged on the end face of the cylinder (10) in the first direction, and the electromagnetic transducer further comprises a second annular flange (12) and a third annular flange (13);

a sunken step is formed in the periphery of the radiation piece (4), and the part, close to the inner side, of the first sealing piece (71) is clamped between the sunken step and the second annular flange plate (12) and is fixedly connected with the sunken step and the second annular flange plate (12);

the part of the first sealing element (71) close to the outer side is clamped between the first annular flange plate (11) and the third annular flange plate (13) and is fixedly connected with the first annular flange plate (11) and the third annular flange plate (13).

5. An electromagnetic transducer according to claim 1, wherein: the radiation piece (4) is a film radiation piece, and the film radiation piece forms a tension structure;

the film type radiation part is an integral structure formed by mutually connecting a cylindrical part (41) and a circular part (42) positioned on the outer side of the cylindrical part (41), and the axial direction of the cylindrical part (41) and the axial direction of the circular part (42) are superposed with the axial direction of the cylinder body (10); the height of the cylindrical part (41) is greater than that of the circular part (42); the maximum size of the film type radiation piece in the axial direction of the cylinder (10) is not more than half of the outer diameter of the circular ring part (42);

the end face, facing the fixed seat (6), of the cylindrical part (41) is fixedly provided with the armature (1);

the electromagnetic transducer further comprises M first fasteners (81) which are arranged along the circumference of the film type radiation piece at intervals and fixedly connect the edge part of the film type radiation piece with the cylinder body (10), wherein M is more than or equal to 3.

6. An electromagnetic transducer according to claim 5, wherein: the membrane type radiation piece is made of any one of titanium alloy, stainless steel and 40 CrNiMoA.

7. The electromagnetic transducer of claim 5, characterized in that a reinforcing member protruding away from the fixed base (6) is provided on the outer end face of each film-type radiator, the reinforcing member is a symmetrical structure centered on the center of the circle of the outer end face of the film-type radiator, and the reinforcing member is fixedly connected with the film-type radiator or is an integral structure.

8. An electromagnetic transducer according to claim 7, wherein: the thickness of the reinforcing piece is gradually reduced from a position close to the axis of the cylinder body (10) to a position far away from the axis of the cylinder body (10).

9. An electromagnetic transducer according to claim 8, wherein: the reinforcing part is an auxiliary film type radiation part (43), the auxiliary film type radiation part (43) is of a rotator structure and is provided with a first circular end face (43 a) and a second circular end face (43 b) which are oppositely arranged, and the axis of the auxiliary film type radiation part (43) is superposed with the axis of the cylinder body (10); the radius of the first circular end surface (43 a) is smaller than that of the second circular end surface (43 b); the thickness of the auxiliary film type radiation piece (43) is gradually reduced from the position of the circumference of the first circular end face (43 a) to the position of the circumference of the second circular end face (43 b); the second circular end face (43 b) is connected with the outer end face of the film type radiation piece, so that the auxiliary film type radiation piece (43) and the film type radiation piece form an integral structure; the auxiliary film type radiation piece (43) and the film type radiation piece are made of the same material; the sum of the maximum sizes of the film radiation piece and the auxiliary film radiation piece (43) in the axial direction of the cylinder (10) is not more than half of the outer diameter of the circular ring part (42).

10. An electromagnetic transducer according to claim 1, wherein: and a second sealing element (72) is connected between the fixed seat (6) and the barrel (10).

11. An electromagnetic transducer according to any one of claims 1-10, wherein: and an acceleration sensor (101) for measuring the acceleration of the radiation piece (4) in the axial direction of the cylinder body is arranged on the radiation piece (4).

12. An electromagnetic transducer according to any one of claims 1-10, wherein: and a temperature sensor (102) is arranged on the excitation structure (2).

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