A new type of miniaturized moving coil movement

Abstract

The present invention discloses a novel miniaturized moving coil movement, belonging to the technical field of electromagnetic detection sensors. The movement is composed of an upper yoke, an upper spring piece, an upper aluminum frame, an upper wire blocking rib, a middle non-metal frame, a housing, a lower wire blocking rib, a lower aluminum frame, a lower spring piece, a magnet, and a lower yoke. This solution uses a composite of non-metal materials and aluminum material parts. The composite structure removes all metal wire blocking rib structures made of aluminum parts and changes them into non-metal wire blocking ribs and a middle non-metal frame. Compared with the prior art, the present invention realizes the feasibility of replacing the traditional seismic prospecting technology system with a nodal instrument, solves the chronic problem of the contradiction between the sensitivity and miniaturization of a single magnet detector movement, breaks through the sensitivity upper limit given by the new national standard implemented on October 1, 2020, and can greatly reduce the manufacturing cost and the field construction operation cost. At the same time, it facilitates the construction operation in various complex environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of electromagnetic detection sensors, and particularly relates to a novel miniaturized moving coil movement. Background Art

[0002] Traditional seismic exploration acquisition systems mainly consist of three parts: geophones, acquisition stations, and seismographs. Among them, after the geophone converts the seismic reflection signal into an analog electrical signal, it is transmitted to the acquisition station. The acquisition station converts the analog electrical signal into a digital electrical signal and then transmits it to the seismograph. The seismograph stores these digital electrical signals, thus completing the acquisition of seismic signals. With the further improvement of the requirements for cost control in oil and gas exploration, the shortcomings of traditional seismic exploration acquisition systems, such as complex construction operations, high labor costs, low efficiency, and being restricted by terrain, have become increasingly prominent. Therefore, the latest seismic exploration acquisition system - node instrument - has emerged internationally.

[0003] The node instrument integrates the functions of geophones, acquisition stations, and seismographs in traditional seismic acquisition systems to form a miniature independent seismic exploration acquisition system. This system has many advantages such as simple construction operations, low labor costs, high efficiency, and being unrestricted by terrain, and is favored by industry personnel. In traditional seismic exploration acquisition systems, geophones, acquisition stations, and seismographs are in a discrete state. Geophones can be a series combination of 12 units or single units, while only single geophones are allowed in node instruments. Therefore, there are certain restrictions on the external dimensions of the geophone movement. The following is a comparison table (see Table 1) of the geophones currently used in node instruments and the main items of concern with the corresponding items in traditional seismic exploration acquisition systems. Comparison Table 1 of the Main Items of Geophones Used in Node Instruments and Traditional Systems:

[0004]

[0005] From the comparison in Table 1, it can be clearly seen that the geophones used in node instruments are significantly inferior to those used in traditional systems in terms of sensitivity and internal resistance. The working principle of moving coil geophones is similar to that of generators, and their transmission load-bearing and anti-interference capabilities depend on the power they generate. According to the formula N = V 2 / R - Equation ①, it can be known that V in the formula is equivalent to the sensitivity of the geophone, and R is equivalent to the internal resistance of the geophone. Therefore, the higher the sensitivity V, the greater the generated power N, and the smaller the internal resistance R, the greater the generated power N. Obviously, the geophones currently used in node instruments are not ideal. So, what about the various single geophone movements currently introduced? We list two representative single geophone movements for comparison with the geophone movement desired by node instruments (see Table 2). Comparison Table 2 of the Geophone Movement Desired by Node Instruments and Two Typical Movements.

[0006]

[0007] It can be clearly seen from Table 2 that these two typical movement cores cannot meet the requirements of the nodal seismograph for the movement core. Therefore, it seems that the current single geophone movement cores cannot meet all the requirements of the nodal seismograph for the movement core.

[0008] The following analyzes the reasons why the above-mentioned movement cores cannot meet the requirements of the nodal seismograph: First, analyze smart solo. Solo belongs to the type with a small volume and relatively low sensitivity. According to the total damping coefficient formula: h = h1 + h2 = G 2 / 4πfM (R1 + R2)+δbHG / p*w —② In formula ②, h1 is the electromagnetic damping coefficient, and h2 is the eddy current damping coefficient. When the geophone movement core is small, the mass M of the inertial body will inevitably become lighter. If the sensitivity is in a relatively high state, the electromagnetic damping h1 will increase sharply. At the same time, due to the adoption of an all-aluminum coil frame structure, such as Figure 1As shown, when the wire frame moves up and down, the winding wall thickness δ of the all-aluminum coil frame and the wire blocking rib b2 have a sufficient relationship of cutting magnetic lines of force with the magnetic conduction width b, maximizing the area s = 2δb + 4δ1b2 of the aluminum material cutting the magnetic lines of force. This causes a sharp increase in the eddy current damping h2. The sharp increase in these two parts of the damping ultimately makes the total damping coefficient h exceed the range of the special detector testing instrument. This has become an inherent defect in improving the sensitivity of the small-volume all-aluminum coil frame movement, and it is also the fundamental reason why the sensitivity of the smart solo small-volume detector movement can only reach 80 v / m / s. However, Hebei Yongcheng [Patent Go1v1 / 18(2006.01)] achieved the result of an all-aluminum coil frame with high sensitivity. The specific method is to reduce the axial dimension of the winding window and supplement the reduced area to the radial direction to ensure that the number of winding turns remains unchanged. Thus, ensuring that the influence of the number of winding turns on the sensitivity remains unchanged. At the same time, the radial area is appropriately increased and the wire diameter is thickened to ensure that its resistance value does not exceed the requirements of the node instrument. At this time, the mass M of the inertial body has a relatively large increase. It can be known from formula ② that when the inertial body M increases, the electromagnetic damping coefficient h1 decreases, achieving the effect of reducing electromagnetic damping and basically balancing the increase in electromagnetic damping caused by the increase in sensitivity. Moreover, when the axial dimension of the winding window decreases, the magnetic conduction width can also be reduced, which also has the effect of reducing the eddy current damping h2. Thus, the total damping coefficient h can not exceed the range of the special detector testing instrument, meeting the requirements of the node instrument for the damping coefficient. However, the cost of doing this is that the volume of the movement becomes much larger, and the increase in the radial dimension will also make the magnetic circuit length l2 longer. According to the magnetomotive force equation H2 = H1l1 / 2l2 - In formula ③, H2 is the magnetic field strength in the air gap, H1 is the magnetic field strength of the magnet, l1 is the height of the magnet, and l2 is the length of the air gap. It can be seen from formula ③ that when l2 increases, H2 decreases, and the strength of H2 determines the magnetoelectric conversion efficiency, which also determines the strength of the sensitivity. Therefore, the stronger H2 is, the stronger the sensitivity is, and the weaker H2 is, the weaker the sensitivity is. So when l2 becomes longer, the sensitivity decreases sharply. In order to ensure that the sensitivity does not decrease, the performance of the magnet is increased desperately, almost using the current highest magnet performance to make up for the reduced sensitivity, which makes the cost of the magnet increase by 10 times, and the volume still cannot meet the requirements of the node instrument.

[0009] To sum up, the common feature of all the moving coil detectors available on the market is that they all adopt a single-magnet magnetic circuit structure, as shown in Figure 1 and Figure 2, its magnetic circuit consists of an inner magnetic circuit and an outer magnetic circuit. The inner magnetic circuit is composed of an upper yoke and three lower yokes and a magnet 2, and the outer magnetic circuit is borne by the outer shell 4. In order to better meet the requirements of the node instrument for the size of the geophone core body, it is necessary to reasonably control the radial size of the geophone core body. At the same time, in order to ensure a sufficient number of turns of the winding, therefore, the winding window size of a single magnet should be: larger in the axial dimension and smaller in the radial dimension. When the coil makes the maximum displacement movement, the coil package should be in a uniform magnetic field. The magnetic permeability width of the yoke should be greater than the axial dimension of the coil package. In this case, the following situation will occur: if the height of the magnet is reduced, the source energy of the magnet will decrease, resulting in a sharp decrease in sensitivity; if the height of the magnet is increased, obvious axial and radial magnetic leakage phenomena will occur. This magnetic leakage phenomenon causes a large loss of the magnetoelectric conversion efficiency, resulting in a great discount in the increase of sensitivity. This has become a key point in improving the sensitivity of single-magnet geophones. Due to the adoption of the structure of an all-aluminum frame coil skeleton with a coil package, when the coil makes the maximum displacement movement, in order to ensure that the coil package is in a uniform magnetic field, the magnetic permeability width of the yoke should be greater than the axial winding dimension of the coil package. At this time, the amount of magnetic force lines cut by the aluminum skeleton of the coil reaches the maximum, resulting in the maximum eddy current on the coil skeleton, causing the eddy current damping to reach the maximum. Coupled with the pursuit of high sensitivity, the electromagnetic damping h1 also reaches the maximum, ultimately resulting in the total damping h exceeding the range of the detection instrument. Moreover, this high-damping state will also make the geophone react sluggishly, which is another bottleneck of the current single-magnet geophone. Some technical personnel have also tried to adopt the composite coil frame movement technology to change the existing problems. The specific technical idea is to make the coil frame by the combination of non-metallic materials and aluminum materials, such as Figure 3As shown, the proportion of aluminum material is reduced, resulting in a significant reduction in eddy current damping, so that the total damping coefficient does not exceed the range of the detection instrument. The price of doing this is that since the composite material is stacked on the wall thickness δ of the aluminum material winding, occupying the radial space of the winding, the area of the winding window is reduced, which also causes the number of winding turns to decrease. The decrease in the number of winding turns directly leads to a decrease in sensitivity, resulting in a situation where one thing is gained while another is lost. If the area of the winding window is increased, the magnetic path length l2 increases. When l2 increases, the magnetic field strength H2 will necessarily decrease sharply, leading to a decrease in sensitivity. Eventually, the result is the same as that of Hebei Yongcheng. With further comparison of data, it is found that the volume size, sensitivity, internal resistance, damping coefficient, and anti-drop ability required by the movement are all closely related to the magnetic conduction width b and the corresponding winding window width b1. This is because when the magnetic conduction width b of the yoke iron < the winding width b1, the magnetic lines of force in the annular air gap of the geophone are prone to be non-uniform. The magnetic flux density in the middle part is relatively large, and the parts near both ends are relatively small. The most uneven part is in the upper and lower end regions of the annular air gap. The uneven distribution of the magnetic lines of force intensifies as its magnetic induction intensity increases. At the same time, due to structural influence, the distribution of the leakage magnetic lines of force at the upper and lower outer ends of the air gap is also inconsistent. This non-uniform distribution causes a non-linear relationship between the current or terminal voltage generated in the coil when the coil moves up and down to cut the magnetic lines of force, that is, when the coil is at its maximum displacement, the magnetic flux Φ swept through must have a uniform intensity, otherwise the generated voltage is not proportional to the movement speed of the coil. It changes according to the instantaneous density of the magnetic flux it cuts, resulting in an increase in harmonic distortion. When the magnetic conduction width b = the winding width b1, after the movement is subjected to a drop impact, the spring piece has a certain amount of collapse. At this time, when the coil is at its maximum displacement, the magnetic flux swept through by both ends of the coil is also in a non-linear state, resulting in an increase in harmonic distortion. When the magnetic conduction width b > the winding width b1, the magnetic lines of force in the annular air gap of the movement are prone to form uniformity. Even after the movement is subjected to a drop impact, the coil will still be covered by a uniform magnetic field, enabling the movement to maintain a good non-distorted voltage. However, this structure is prone to an increase in eddy current damping. Increasing the magnetic conduction width will also cause a decrease in the magnetic field strength in the annular air gap, resulting in a decrease in sensitivity. These mutually influencing and contradictory results have been formed. So far, the problems existing in the single-magnet steel geophone are obvious. One is the over-range damping and volume problems brought about by adopting an all-aluminum frame structure in pursuit of high-sensitivity miniaturization; the second is the serious axial and radial magnetic leakage problems in pursuit of high sensitivity; the third is the problem of reducing the number of winding turns when using a composite coil to reduce eddy current damping, which has become a bottleneck for the single-magnet steel geophone to meet the requirements of the node instrument for small volume, high sensitivity, and appropriate damping. Whether these bottleneck restrictions can be broken also determines the survival and fate of this type of geophone. Innovation is difficult, and innovation for a highly mature product like a moving coil geophone is even more difficult. Summary of the Invention

[0010] In view of this, the present invention provides a new type of miniaturized moving coil movement, which uses non-metallic materials and aluminum material parts to compound the coil bobbin. The composite structure removes all metal wire retaining rib structures made of aluminum parts and changes them into non-metallic wire retaining ribs and a non-metallic frame in the middle. At the same time, aiming at the problems of axial and radial magnetic leakage, axial magnetic isolation attenuation technology and radial magnetic focusing technology are respectively adopted for treatment, and good results have been achieved. The specific approach is as follows: for the problem of axial magnetic leakage, a magnetic isolation attenuation gasket is provided between the top of the magnet and the bottom of the upper yoke, and another magnetic isolation attenuation gasket is provided between the bottom of the magnet and the top of the lower yoke. Through the magnetic isolation attenuation effect, the axial magnetic leakage is greatly suppressed. The magnetic isolation materials used can be non-magnetic materials such as bismuth, copper, and aluminum; for the problem of radial magnetic leakage, a material compounding technology is carried out on the outer shell. By using the good magnetic focusing effect of permalloy or microcrystalline materials, the radial magnetic leakage is well suppressed. Compared with the prior art, the present invention realizes the feasibility of replacing the traditional seismic geophysical exploration technology system with a nodal instrument, breaks through the chronic problem of the contradiction between the sensitivity and miniaturization of a single geophone movement, saves the field construction operation cost, and facilitates the construction operation in various complex environments.

[0011] The present invention solves the above problems through the following technical means:

[0012] A new type of miniaturized moving coil movement, characterized in that it includes an upper yoke, an upper spring piece, an upper aluminum frame, an upper wire retaining rib, a middle non-metallic frame, a composite outer shell, a lower wire retaining rib, a lower aluminum frame, a lower spring piece, a magnet, and a lower yoke, wherein: the outer shell is a composite material and consists of a shell and a cover body, and the shell and the two end cover bodies form a sealed cavity; the magnet is installed between the upper yoke and the lower yoke and fixed in the middle of the outer shell; the upper aluminum frame, the upper wire retaining rib, the middle non-metallic frame, the lower wire retaining rib, and the lower aluminum frame form a coil bobbin. The upper aluminum frame and the lower aluminum frame are respectively arranged on both sides of the middle non-metallic frame. The upper wire retaining rib is arranged closely on the horizontal plane of the upper aluminum frame, and the lower wire retaining rib is arranged closely on the horizontal plane of the lower aluminum frame. The wire coils are respectively arranged in the annular grooves formed by the upper wire retaining rib and the middle non-metallic frame, and the annular grooves formed by the middle non-metallic frame and the lower wire retaining rib. The wire coils are coupled and matched with the yoke and are connected to the external conductive posts through conductive metal hairsprings; the upper and lower ends of the coil bobbin are elastically connected to both ends of the yoke through the upper spring piece and the lower spring piece respectively.

[0013] Preferably, the middle non-metallic frame is of a ring-shaped open groove structure, and a counterweight is arranged in the ring-shaped open groove structure.

[0014] Preferably, a compensation ring is also arranged in the gap between the upper yoke and the lower yoke, and the compensation ring is sleeved on the magnet.

[0015] Preferably, installation grooves are opened on the upper and lower sides of the back surface of the middle non-metallic frame, and the installation grooves are used to connect the upper aluminum frame and the lower aluminum frame.

[0016] Preferably, a magnetic isolation gasket is further provided between the top of the permanent magnet and the bottom of the upper yoke, and a magnetic isolation gasket is also provided between the bottom of the permanent magnet and the top of the lower yoke. The magnetic isolation material is not only metallic bismuth, but also non-magnetic materials such as copper and aluminum.

[0017] Preferably, it further includes a coil bobbin skeleton, which is composed of an upper aluminum frame, a middle non-metallic frame, and a lower aluminum frame. Among them, the upper aluminum frame, the middle non-metallic frame, and the lower aluminum frame are assembled through a tight fit relationship of shaft holes, and the upper aluminum frame and the lower aluminum frame are respectively fixedly installed at the upper and lower ends of the middle non-metallic frame.

[0018] Preferably, the permanent magnet is made of neodymium iron boron material or aluminum nickel cobalt material. When the permanent magnet is made of aluminum nickel cobalt material, the compensation ring in the magnetic circuit can be omitted.

[0019] Preferably, the upper yoke and the lower yoke are made of industrial pure iron, low-carbon steel, permalloy or high-permeability microcrystalline material.

[0020] Preferably, the outer shell is a composite material outer shell, and a fixing groove is provided on the outer shell, and a permalloy or microcrystalline material strip is wound in the fixing groove.

[0021] Preferably, the upper aluminum frame and the lower aluminum frame are made of aluminum alloy material.

[0022] Preferably, the middle non-metallic frame is made of polycarbonate, polysulfone or reinforced nylon material.

[0023] Preferably, the upper wire blocking rib and the lower wire blocking rib are made of polycarbonate, polysulfone or reinforced nylon material.

[0024] A novel miniaturized moving coil movement of the present invention has the following beneficial effects:

[0025] The movement includes an upper yoke, an upper spring piece, an upper aluminum frame, upper wire blocking ribs, a middle non-metal frame, a composite housing, lower wire blocking ribs, a lower aluminum frame, a lower spring piece, a magnet, and a lower yoke. This solution uses a composite of non-metal materials and aluminum parts. The composite structure removes all metal wire blocking rib structures made of aluminum parts and changes them into non-metal wire blocking ribs and a middle non-metal frame. And it maintains the characteristics of the winding wall of the all-aluminum frame coil holder, enabling the maximum number of winding turns to be obtained when the radial dimension of the winding window does not increase, thus solving the problem of miniaturization of the movement. Thus, the problems of over-range damping caused by the high sensitivity, all-aluminum frame, and miniaturized structure of the current single-magnet geophone; the axial and radial magnetic leakage problems caused by high sensitivity; and the problem of reduced number of winding turns caused by the composite wire holder are all solved. Compared with the prior art, the present invention truly realizes the feasibility of replacing the traditional seismic geophysical exploration technology system with a nodal instrument. At the same time, it breaks through the chronic problem of the contradiction between the sensitivity and miniaturization of the single-magnet geophone movement. In addition, it saves the field construction operation cost, facilitates the construction operation in various complex environments, and accelerates the pace of technological progress in the industry. Secondly, after the volume of the movement is reduced, it saves the material costs of the main precious materials such as magnets and enameled wires used in the manufacture of geophones. Further, it provides a good platform for the technological upgrading of other industries. Finally, this movement breaks through the highest value set for sensitivity in the new national standard GB / T24260—2420 implemented on October 1, 2020. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for the implementation will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 is a schematic diagram of the structure of an existing all-aluminum coil holder;

[0028] Figure 2 is a schematic diagram of the magnetic circuit structure of an existing single magnet;

[0029] Figure 3 is the structure of an existing composite coil holder;

[0030] Figure 4 is a schematic diagram of the overall structure of the present invention;

[0031] Figure 5 is a schematic diagram of the magnetic circuit structure of the single magnet of the present invention.

[0032] Among them, 1 - upper yoke iron, 2 - upper spring piece, 3 - upper aluminum frame, 4 - upper wire blocking rib, 5 - middle non - metal frame, 6 - counterweight, 7 - housing, 8 - lower wire blocking rib, 9 - lower aluminum frame, 10 - lower spring piece, 11 - magnet, 12 - lower yoke iron, 13 - compensation ring, 14 - magnetic isolation gasket, 15 - magnetic concentrating material. Detailed implementation mode

[0033] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present invention. The terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality" is two or more.

[0034] The present invention will be described in detail below with reference to the drawings.

[0035] As Figure 4 and Figure 5 shown, the miniaturized moving - coil movement includes an upper yoke iron 1, an upper spring piece 2, an upper aluminum frame 3, an upper wire blocking rib 4, a middle non - metal frame 5, a housing 7, a lower wire blocking rib 8, a lower aluminum frame 9, a lower spring piece 10, a magnet 11 and a lower yoke iron 12, wherein: The housing 7 is composed of a shell and a cover body. The shell and the two end cover bodies form a sealed cavity. The magnet 11 is installed between the upper yoke iron 1 and the lower yoke iron 12 and fixed in the middle of the housing 7. Concave platforms for installing the magnet 11 are provided at the bottom of the upper yoke iron 1 and the top of the lower yoke iron 12. The upper yoke iron 1 and the lower yoke iron 12 are fixedly installed by the cover body. In the figure, the upper aluminum frame 3, the upper wire blocking rib 4, the middle non - metal frame 5, the lower wire blocking rib 8 and the lower aluminum frame 9 form a coil holder. The upper aluminum frame 3 and the lower aluminum frame 9 are respectively arranged on both sides of the middle non - metal frame 5. The upper wire blocking rib 4 is arranged closely along the horizontal plane of the upper aluminum frame 3, and the lower wire blocking rib 8 is arranged closely along the horizontal plane of the lower aluminum frame 9. The wire coils are respectively arranged in the annular grooves formed by the upper wire blocking rib 4 and the middle non - metal frame 5, and in the annular grooves formed by the middle non - metal frame 5 and the lower wire blocking rib 8. The wire coils are coupled and matched with the yoke iron and connected to the external conductive posts through conductive metal wires. The upper and lower ends of the coil holder are elastically connected to the two ends of the yoke iron through the upper spring piece 2 and the lower spring piece 10 respectively.

[0036] In this example, the non-metallic frame 5 is a ring-shaped open groove structure, and a counterweight 6 is arranged inside the ring-shaped open groove structure. The non-metallic frame 5 is made of polycarbonate, polysulfone or reinforced nylon material. A compensation ring 13 is also arranged in the gap between the upper yoke 1 and the lower yoke 12. The compensation ring 13 is sleeved on the permanent magnet 11. The permanent magnet 11 is made of neodymium iron boron material or alnico material. When the permanent magnet is made of alnico material, the compensation ring in the magnetic circuit can be omitted. Figure 4 In the coil frame skeleton, it consists of three parts: the upper aluminum frame 3, the non-metallic middle frame 5, and the lower aluminum frame 9. Among them, the upper aluminum frame 3, the non-metallic middle frame 5, and the lower aluminum frame 9 are fixedly installed at the upper and lower ends of the non-metallic middle frame 5 through the interference fit relationship of the shaft holes. In order to enhance the connection strength between them, an appropriate adhesive can be applied to the mating surface to form an integral coil frame skeleton. In addition, the upper yoke 1 and the lower yoke 12 are made of industrial pure iron, low-carbon steel, permalloy or high-permeability microcrystalline material. The upper aluminum frame 3 and the lower aluminum frame 9 are made of aluminum alloy material. The upper wire retaining rib 4 and the lower wire retaining rib 8 are made of polycarbonate, polysulfone or reinforced nylon material.

[0037] It should be noted that a magnetic isolation gasket 14 is also arranged between the top of the permanent magnet 11 and the bottom of the upper yoke 1, and a magnetic isolation gasket 14 is also arranged between the bottom of the permanent magnet 11 and the top of the lower yoke 12. The magnetic isolation material is not only bismuth metal, but also non-magnetic materials such as copper and aluminum.

[0038] In this embodiment, a composite of non-metallic materials and aluminum parts is adopted. All the wire retaining structures made of aluminum parts are removed from this part of the composite structure and changed to non-metallic wire retaining ribs 4, 8 and the non-metallic middle frame 5. The materials selected for the non-metallic wire retaining ribs 4, 8 and the non-metallic middle frame 5 are insulating materials with good strength such as polycarbonate, polysulfone, and reinforced nylon. The purpose of doing this is to maintain the good mechanical stiffness of the all-aluminum coil frame and the smallest proportion of aluminum material. Thus, the influence of aluminum material on eddy current is minimized. When the coil frame makes the maximum displacement movement, all the wire retaining ribs participate in cutting the magnetic force lines, and a certain amount of eddy current is inevitably generated in the wire retaining ribs. The eddy current area converted by each wire retaining rib accounts for about 12.5% of the total eddy current area, and the eddy current area of 4 wire retaining ribs accounts for about 50% of the total eddy current area. Removing all the wire retaining ribs means that the eddy current damping coefficient h2 can be reduced by about 50%. After a hard anodizing insulation treatment on the used aluminum material, the total eddy current damping can be reduced by about 20% or more. The two items together can reduce the eddy current damping coefficient h2 by about 70% or more. Thus, the total damping coefficient can be controlled to meet the damping coefficient required by the node instrument.

[0039] It should be noted that the commonly used aluminum materials include: 2024-T351 series, Ly12 series and other aluminum alloy materials. The second key technical point is that while significantly reducing the eddy current damping coefficient h2, the all-aluminum frame winding window structure is maintained. Therefore, the magnetic circuit length l2 can be made the shortest, that is, the magnetic field strength H in the air gap is maximized, maximizing the sensitivity generated in this part. At the same time, the effective area of the winding window is not affected at all, ensuring a sufficient number of winding turns W. According to the electromechanical coupling coefficient formula G = W * dφ / dx — ③, where G is the electromechanical coupling coefficient, which is equivalent to the open-circuit sensitivity of the geophone core. W is the number of winding turns, and dφ / dx is the magnetic current gradient. The larger the magnetic current gradient, the greater the magnetic field strength in the geophone air gap. Therefore, this structure can obtain the maximum sensitivity. At the same time, since the radial size does not increase, the purpose of miniaturization is achieved;

[0040] It should be further noted that the third key technical point of the above structure is that through a large number of comparison tests, the dimensional relationship between the optimal magnetic permeability width and the width and height of the winding window is obtained, that is: the dimensional range of the magnetic permeability width b is 9 - 13 mm, the dimensional range of the winding window width b1 is 7 - 11 mm, and the dimensional range of the winding window height is 2.0 - 3.0 mm. Take a set of data combinations from the above data. For example, the magnetic permeability width is: 11 mm, the winding window width dimension is 9 mm, and the winding window height dimension is 2.7 mm. According to the requirements of the node instrument, the data is shown in Table 3, the comparison table of the new core and the data expected by the node instrument.

[0041]

[0042] It can be clearly seen from Table 3 that the data of the new geophone core meet the requirements of the node instrument. Particularly gratifying is that the sensitivity of the new core exceeds that of the American smart solo by about 49%. Sensitivity is the prerequisite for the node instrument to obtain seismic information, and the size of the sensitivity directly determines the amount of information obtained by the node instrument. The assembly process of the composite coil frame is: first, the wire blocking ribs 4 and 8 are respectively combined with the upper aluminum frame 3 and the lower aluminum frame 9 as shown in Figure 4 and glued together, and then glued to the middle non-metallic frame 5. The composite wire frame is completed. The manufacturing method of the composite material shell is to wind permalloy or microcrystalline material strip in the groove of the shell and close the opening with glue or welding method. The other assembly processes of the geophone are the same as those of the conventional geophone. Compared with the existing technology, the present invention realizes the feasibility of replacing the traditional seismic geophysical exploration technology system with the node instrument, breaks through the chronic problem of the contradiction between the sensitivity and miniaturization of a single geophone core, saves the field construction operation cost, and facilitates the construction operation in various complex environments.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A novel miniaturized moving coil movement, characterized in that, It includes an upper yoke iron (1), upper spring pieces (2), upper aluminum frame (3), upper wire blocking ribs (4), middle non-metal frame (5), counterweight (6), housing (7), lower wire blocking ribs (8), lower aluminum frame (9), lower spring pieces (10), permanent magnet (11) and lower yoke iron (12), where: The housing (7) is composed of a shell and a cover body, and the shell and the two end cover bodies form a sealed cavity; The permanent magnet (11) is installed between the upper yoke iron (1) and the lower yoke iron (12) and fixed in the middle of the housing (7); The upper aluminum frame (3), upper wire blocking ribs (4), middle non-metal frame (5), lower wire blocking ribs (8) and lower aluminum frame (9) form a coil bobbin. The upper aluminum frame (3) and the lower aluminum frame (9) are respectively arranged at both ends of the middle non-metal frame (5). The upper wire blocking ribs (4) are arranged closely on the horizontal plane of the upper aluminum frame (3), and the lower wire blocking ribs (8) are arranged closely on the horizontal plane of the lower aluminum frame (9). The wire coils are respectively arranged in the annular grooves formed by the upper wire blocking ribs (4) and the middle non-metal frame (5), and in the annular grooves formed by the middle non-metal frame (5) and the lower wire blocking ribs (8). The wire coils are coupled and matched with the yoke iron and connected to the external conductive posts through conductive metal spiral wires; The upper and lower ends of the coil bobbin are elastically connected to both ends of the yoke iron through the upper spring pieces (2) and the lower spring pieces (10) respectively; The middle non-metal frame (5) is of a ring-shaped open groove structure, and a counterweight (6) is arranged in the ring-shaped open groove structure; A compensation ring (13) is also arranged in the gap between the upper yoke iron (1) and the lower yoke iron (12), and the compensation ring (13) is sleeved on the permanent magnet (11); A magnetic isolation gasket (14) is also arranged between the top of the permanent magnet (11) and the bottom of the upper yoke iron (1), and a magnetic isolation gasket (14) is also arranged between the bottom of the permanent magnet (11) and the top of the lower yoke iron (1); It also includes a coil bobbin skeleton, which is composed of an upper aluminum frame (3), a middle non-metal frame (5) and a lower aluminum frame (9). Among them, the upper aluminum frame (3), the middle non-metal frame (5) and the lower aluminum frame (9) are assembled through a tight fit relationship of shaft holes, and the upper aluminum frame (3) and the lower aluminum frame (9) are respectively fixedly installed at the upper and lower ends of the middle non-metal frame (5); The permanent magnet (11) is made of neodymium iron boron material or aluminum nickel cobalt material. When the permanent magnet is made of aluminum nickel cobalt material, the compensation ring (13) in the magnetic circuit can be omitted; The upper yoke iron (1) and the lower yoke iron (12) are made of industrial pure iron, low-carbon steel, permalloy or high-permeability microcrystalline material; The housing (7) is a composite material housing, and fixing grooves are opened on the housing (7), and permalloy or microcrystalline material strips are wound in the fixing grooves; The middle non-metal frame (5) is made of polycarbonate, polysulfone or reinforced nylon material; The upper wire blocking ribs (4) and the lower wire blocking ribs (8) are made of polycarbonate, polysulfone or reinforced nylon material.

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