Distribution transformer quasi-zero stiffness low-frequency vibration isolator and manufacturing method

Abstract

A quasi-zero-stiffness low-frequency vibration isolator for a distribution transformer and a manufacturing method thereof relate to the technical field of distribution transformers, and comprise a shell, the shell comprises a vibration isolator upper shell and a vibration isolator lower shell, and a first fixing piece and a second fixing piece are arranged on the inner sides of the vibration isolator upper shell and the vibration isolator lower shell; the bearing springs are used for connecting the vibration isolator upper shell and the vibration isolator lower shell and comprise the first bearing spring and the second bearing spring, the first end of the first bearing spring and the first end of the second bearing spring are connected with the bottom of the inner side of the vibration isolator lower shell, and the second end of the first bearing spring and the second end of the second bearing spring are connected with the inner side of the vibration isolator upper shell; the resonance adjustor is used for adjusting the vibration frequency to be in a resonance state with equipment vibration; and the air spring is used for connecting the resonance adjustor with the vibration isolator upper shell and the vibration isolator lower shell. A parallel positive and negative stiffness structure is adopted, so that the quasi-zero stiffness characteristic is realized at a static balance position, and the stability of a vibration isolation system is maintained.

Description

Technical Field

[0001] The present invention belongs to the technical field of distribution transformers, and particularly relates to a quasi-zero stiffness low-frequency vibration isolator for distribution transformers and a manufacturing method thereof. Background Art

[0002] With the acceleration of China's urbanization process and the intensive layout of power facilities, as the core equipment of the urban power grid, the installation location of distribution transformers is getting closer and closer to noise-sensitive areas such as residential areas and commercial areas, and higher requirements are faced in terms of operation stability and environmental adaptability. In the process of new urbanization, the spatial distance between distribution facilities and residential living areas is continuously shortened, and the low-frequency vibration noise (100 - 500 Hz frequency band) generated during the operation of transformers has become an outstanding problem affecting the human settlement environment and a key factor restricting the planning of urban power facilities. Traditional passive vibration isolation technologies have technical bottlenecks such as relatively high natural frequencies and obvious attenuation of vibration isolation efficiency in the low-frequency band (<200 Hz), and it is difficult to meet the requirements of the current "Ambient Noise Quality Standard" (GB3096 - 2021) for the night noise limit in Class 1 sound environment functional areas.

[0003] Currently, the commonly used rubber vibration isolators and metal spring vibration isolators in engineering practice have significant technical defects: rubber vibration isolators are prone to creep failure under long-term loads, and have relatively large low-frequency dynamic stiffness; although metal spring vibration isolators can provide relatively low natural frequencies, additional dampers need to be configured to suppress the high-frequency resonance amplification effect. Although the Helmholtz resonance type vibration isolation device can achieve vibration absorption at specific frequencies, there are engineering application limitations such as narrow effective frequency bands and large structural sizes.

[0004] The quasi-zero stiffness vibration isolation technology can reduce the natural frequency of the system to below 1 Hz by introducing non-linear elastic elements (such as negative stiffness mechanisms), and theoretically can achieve full-frequency vibration isolation. However, existing quasi-zero stiffness structures generally have problems such as insufficient bearing capacity and poor dynamic stability, and there is still no mature solution in the field of low-frequency vibration isolation for large-mass equipment such as distribution transformers (the single-unit weight is 3 - 8 tons). Summary of the Invention

[0005] The present invention provides a quasi-zero stiffness low-frequency vibration isolator for distribution transformers and a manufacturing method thereof, which can isolate and reduce the vibration noise generated during the operation of distribution transformers. By precisely implementing measures on the vibration transmission path and utilizing the mechanical properties of the quasi-zero stiffness vibration isolator, the vibration energy transmitted to the surrounding structures can be significantly reduced, and the noise propagation caused by vibration can be effectively controlled.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A quasi-zero stiffness low-frequency vibration isolator for distribution transformers, comprising:

[0008] A housing, said housing including an upper vibration isolator housing and a lower vibration isolator housing, and a first fixing member and a second fixing member are provided inside the upper vibration isolator housing and the lower vibration isolator housing;

[0009] Load-bearing springs, used to connect the upper vibration isolator housing and the lower vibration isolator housing, including a first load-bearing spring and a second load-bearing spring. The first ends of the first load-bearing spring and the second load-bearing spring are respectively connected to the bottom inside the lower vibration isolator housing, and the second ends of the first load-bearing spring and the second load-bearing spring are respectively connected to the inside of the upper vibration isolator housing;

[0010] A resonance adjuster, used to adjust the vibration frequency to be in a resonance state with the equipment vibration;

[0011] An air spring, used to connect the resonance adjuster with the upper vibration isolator housing and the lower vibration isolator housing.

[0012] As a further technical solution of the present invention, the air spring includes a first air spring, a second air spring, a third air spring and a fourth air spring. The first ends of the first air spring and the second air spring are connected to the inside of the upper vibration isolator housing, the second ends of the first air spring and the second air spring are connected to the resonance adjuster, the first ends of the third air spring and the fourth air spring are connected to the bottom of the lower vibration isolator housing, and the second ends of the third air spring and the fourth air spring are connected to the resonance adjuster.

[0013] As a further technical solution of the present invention, the resonance adjuster includes:

[0014] A sleeve, a spring connection disc is arranged inside the sleeve, and a third fixing member for connecting the air spring is arranged on the outside of the sleeve;

[0015] An upper spring, arranged at the upper end of the spring connection disc and connected to the spring connection disc;

[0016] A lower spring, arranged at the lower end of the spring connection disc and connected to the spring connection disc;

[0017] An end cap, arranged on the upper side of the upper spring and connected to the upper spring.

[0018] As a further technical solution of the present invention, the upper spring and the lower spring are tower springs, and the bottom of the upper spring and the bottom of the lower spring are respectively connected to the upper side and the lower side of the spring connection disc; the top of the upper spring is embedded in the end cap and connected to the end cap.

[0019] As a further technical solution of the present invention, the upper vibration isolator housing is provided with an adjustment screw hole, and an end cap is arranged in the adjustment screw hole.

[0020] As a further technical solution of the present invention, the air spring is in a hinged structure with the first fixing member, the second fixing member and the third fixing member.

[0021] As a further technical solution of the present invention, a vibration isolation plate is further arranged on the upper side of the upper housing of the vibration isolator, and the vibration isolation plate is a honeycomb vibration isolation plate.

[0022] As a further technical solution of the present invention, the honeycomb vibration isolation plate includes a housing, a honeycomb structure is arranged inside the housing, the housing is made of one of stainless steel and carbon steel materials, and the honeycomb structure is made of one of rubber and polyurethane foam materials.

[0023] As a further technical solution of the present invention, the upper housing and the lower housing of the vibration isolator are made of one of stainless steel, carbon steel and aluminum alloy.

[0024] In a second aspect, the present invention provides a method for manufacturing a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer, including the following steps:

[0025] Determine the linear positive stiffness of the load-bearing spring according to the static load borne by the vibration isolator;

[0026] Determine the nonlinear negative stiffness according to the linear positive stiffness, and determine the stiffness and tilt angle of the air spring;

[0027] Conduct a vibration test on the distribution transformer, and design the stiffness and mass parameters of the resonance adjuster according to the vibration frequency of the equipment;

[0028] Assemble the load-bearing spring, the air spring and the resonance adjuster.

[0029] Advantages of the present invention:

[0030] 1. The present invention adopts a parallel positive and negative stiffness structure, enabling it to achieve quasi-zero stiffness characteristics at the static equilibrium position. Reasonable design of the quasi-zero stiffness vibration isolator can achieve the effect of low-frequency vibration isolation, and at the same time can provide sufficient bearing capacity to maintain the stability of the vibration isolation system.

[0031] 2. The present invention combines the multi-stage stiffness coupling of the positive and negative stiffness structure with the dynamic tuning mechanism of the resonance adjustable system, and realizes the efficient isolation of low-frequency vibration through the cooperative action of multiple springs, providing a solution with a compact structure, stable performance and controllable cost for the low-frequency vibration control of heavy equipment such as distribution transformers, meeting the development needs of the intelligent grid for the environmental friendliness of equipment, and having broad application prospects.

[0032] 3. The present invention has a quasi-zero stiffness low-frequency vibration isolator with high bearing capacity, broadband vibration isolation performance and structural compactness, which has important engineering significance for improving the environmental friendliness of distribution facilities. Description of the Drawings

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings required for the description of the embodiments or the prior art.

[0034] Figure 1 Structural diagram of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer proposed by the present invention;

[0035] Figure 2 Cross-sectional view of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer proposed by the present invention;

[0036] Figure 3 Top view of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer proposed by the present invention;

[0037] Figure 4 Left view of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer proposed by the present invention;

[0038] Figure 5 Front view of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer proposed by the present invention;

[0039] Figure 6 Manufacturing flow chart of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer proposed by the present invention;

[0040] Legend description:

[0041] 10 - Outer shell, 20 - Load-bearing spring, 30 - Resonance adjuster, 40 - Air spring, 50 - Vibration isolation plate;

[0042] 101 - Upper outer shell of the vibration isolator, 102 - Lower outer shell of the vibration isolator, 111 - First fixing part, 121 - Second fixing part, 112 - Adjusting screw hole;

[0043] 201 - First load-bearing spring, 202 - Second load-bearing spring;

[0044] 301 - Sleeve, 302 - Upper spring, 303 - Lower spring, 304 - End cover, 311 - Spring connection plate, 312 - Third fixing part;

[0045] 401 - First air spring, 402 - Second air spring, 403 - Third air spring, 404 - Fourth air spring. Detailed implementation manners

[0046] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0047] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0048] A quasi-zero stiffness low-frequency vibration isolator for a distribution transformer provided by the present invention, the main principle of its vibration isolation and noise reduction is that within a specific frequency range, by optimizing the parameters of each spring and their collaborative work, the equivalent stiffness of the vibration isolator system approaches zero. When the equivalent stiffness approaches zero, the response of the device to low-frequency vibration is significantly reduced, thereby achieving the quasi-zero stiffness vibration isolation effect and greatly improving the low-frequency vibration isolation performance.

[0049] See Figures 1 to 5 , the present invention provides a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer, including:

[0050] A housing 10, the housing 10 includes an upper vibration isolator housing 101 and a lower vibration isolator housing 102, and first fixing members 111 and second fixing members 121 are provided inside the upper vibration isolator housing 101 and the lower vibration isolator housing 102;

[0051] Load-bearing springs 20, used to connect the upper vibration isolator housing 101 and the lower vibration isolator housing 102, including a first load-bearing spring 201 and a second load-bearing spring 202. The first ends of the first load-bearing spring 201 and the second load-bearing spring 202 are respectively connected to the bottom inside the lower vibration isolator housing 101, and the second ends of the first load-bearing spring 201 and the second load-bearing spring 202 are respectively connected to the inside of the upper vibration isolator housing 102;

[0052] A resonance adjuster 30, used to adjust the vibration frequency and be in a resonance state with the device vibration;

[0053] An air spring 40 is used to connect the resonance adjuster 30 with the upper housing 101 of the vibration isolator and the lower housing 102 of the vibration isolator.

[0054] In the present invention, the quasi-zero stiffness low-frequency vibration isolator mainly includes a load-bearing spring, an air spring, and a resonance adjustable spring. This vibration isolator is designed as a highly integrated integral body, and its housing is made of a material with high strength and high toughness, which plays a role in protecting the internal structure and connecting the basic support structure with the equipment installation platform. The upper housing 101 of the vibration isolator and the lower housing 102 of the vibration isolator are made of one of stainless steel, carbon steel, and aluminum alloy.

[0055] The resonance adjuster is arranged in the cavity formed by the buckling of the upper housing and the lower housing of the vibration isolator. The load-bearing spring and the air spring are symmetrically distributed on both sides of the resonance adjuster with the resonance adjuster as the center. The load-bearing spring is vertically placed between the upper housing and the lower housing of the vibration isolator, and positioning buckles are welded on the upper housing and the lower housing of the vibration isolator to limit the free deformation of the spring through physical contact, forming an axial movement guide for the spring to ensure that the axis is perpendicular during compression and tension and avoid lateral instability.

[0056] The upper housing of the vibration isolator does not interfere with the lower housing of the vibration isolator. When the equipment vibrates in the vertical direction and the telescopic amounts of the vertical spring and the air spring change, the upper housing and the lower housing of the vibration isolator can move in the vertical direction, enabling the vibration isolator to better adapt to the vibration characteristics of the equipment under different working conditions. Ensure that when the equipment vibrates during startup, acceleration, stable operation, or deceleration, the upper housing and the lower housing of the vibration isolator can respond in a timely manner, ensuring that the internal vibration isolation components are always in the best working state.

[0057] See Figure 2 , in the embodiment of the present invention, the air spring 40 includes a first air spring 401, a second air spring 402, a third air spring 403, and a fourth air spring 404. The first ends of the first air spring 401 and the second air spring 402 are connected to the inner side of the upper housing 101 of the vibration isolator, the second ends of the first air spring 401 and the second air spring 402 are connected to the resonance adjuster 30, the first ends of the third air spring 403 and the fourth air spring 404 are connected to the bottom of the lower housing 102 of the vibration isolator, and the second ends of the third air spring 403 and the fourth air spring 404 are connected to the resonance adjuster 30.

[0058] The load-bearing spring is a positive stiffness element and serves as the main load-bearing structure, providing a linear positive stiffness k z , bearing the static load of the equipment (such as the weight of the distribution transformer) to ensure the static balance of the system. The inclined air spring is a negative stiffness element and is arranged at a symmetrical angle θ. When the system undergoes a vertical displacement z, the inclined spring generates a horizontal component force:

[0059] ;

[0060] Introduce negative stiffness through geometric nonlinear effects to offset the positive stiffness of the load-bearing spring:

[0061] ;

[0062] Total stiffness of the positive and negative stiffness parallel system:

[0063] ;

[0064] where k x is the stiffness of the inclined air spring. By optimizing the parameters, make k t ≈0 near the equilibrium point to form a wide-range quasi-zero stiffness interval.

[0065] The inclined air spring is a piston-type air spring, and its stiffness is:

[0066] ;

[0067] where A is the effective area of the piston, P is the internal air pressure, V is the air chamber volume, and the dynamic adjustment of the stiffness k f is achieved by adjusting V through the piston displacement. The inclined air spring utilizes its unique inclined installation angle. When the equipment vibrates, the air spring is further stretched through the piston movement. Due to its inclined angle θ, the component force of the spring in the vertical direction decreases with the stretching, equivalently generating a negative stiffness effect;

[0068] When the equipment vibrates horizontally, the inclined air spring generates a component force in the horizontal direction. And due to its symmetric layout, the horizontal component forces generated by the two inclined air springs on both sides are equal in magnitude and opposite in direction, forming a resultant force opposite to the vibration direction, which hinders the horizontal vibration of the equipment. When the equipment has torsional vibration, the symmetric inclined air springs will generate component forces in different directions at different positions according to the torsional angle, and the component forces combine to form an anti-torsion moment to suppress the torsional vibration of the equipment, significantly reducing the amplitude of the vibration response of the equipment.

[0069] See Figure 2 , the resonance adjuster 30 in the embodiment of the present invention includes:

[0070] A sleeve 301, a spring connection disk 311 is arranged inside the sleeve 301, and a third fixing member 312 for connecting the air spring 40 is arranged outside the sleeve 301;

[0071] An upper spring 302, which is arranged at the upper end of the spring connection disk 311 and connected to the spring connection disk 311;

[0072] A lower spring 303, which is arranged at the lower end of the spring connection disk 311 and connected to the spring connection disk 311;

[0073] The end cap 304 is disposed on the upper side of the upper spring 302 and is connected to the upper spring 302.

[0074] The resonance adjuster consists of a mass block and an elastic element to form an adjustable mass-spring resonance system, which works based on the resonance principle of mechanical vibration and is connected in parallel with the main vibration isolation system. When the equipment vibrates, the vibration frequency is transmitted to the resonance adjustable system through the vibration isolator. By adjusting the system mass and stiffness , the natural frequency of the resonance system is changed:

[0075] ;

[0076] By changing the stiffness of the resonance adjustable system and mass and then changing the natural frequency of the resonance system . Through precise adjustment, the natural frequency of the resonance system is matched with the equipment vibration frequency, and the resonance adjustable spring system enters the resonance state, canceling the equipment vibration energy and reducing the equipment vibration amplitude.

[0077] The spring connection disk does not contact the sleeve. The main function of the sleeve is a limiter, which limits the horizontal offset of the resonance adjuster and ensures that it can only move in the vertical direction.

[0078] In the embodiment of the present invention, the upper spring 302 and the lower spring 303 are tower springs, and the bottom of the upper spring 302 and the bottom of the lower spring 303 are respectively connected to the upper side and the lower side of the spring connection disk 311; the top of the upper spring 302 is embedded in the end cap 304 and is connected to the end cap 304.

[0079] The vibration isolator upper housing 101 is provided with an adjustment screw hole 112, and the end cap 304 is disposed in the adjustment screw hole 112. The upper end of the upper spring is unrestrained and embedded in the end cap. The end cap is threadedly connected to the vibration isolator upper housing. By changing the position of the end cap through threaded connection, the telescopic amount of the upper and lower springs is changed. By changing the telescopic amount, the effective number of turns and the contact state are changed to achieve the stiffness k d adjustment of the resonance adjuster. The end cap is adjustably fixed by a rotary extension buckle.

[0080] The air spring 40 is an articulated structure with the first fixing member 111, the second fixing member 121, and the third fixing member 312. The flexibility of the vibration isolator is improved. In the face of the complex and changeable vibration modes of the equipment, the vibration isolator can respond quickly. Whether it is the working condition change during the startup and operation of the equipment or the irregular vibration caused by external impact, the articulated characteristics of the springs can enable them to adjust their postures in a timely manner and better play their respective vibration isolation roles to ensure that the equipment vibration is always within the controllable range.

[0081] After the quasi-zero stiffness low-frequency vibration isolator is designed according to the weight and vibration frequency of the distribution transformer, corresponding classical vibration isolation components are added according to the actual application requirements to complete the overall structure design of the vibration isolator. That is, a vibration isolation plate 50 is also provided on the upper side of the upper shell 101 of the vibration isolator, and the vibration isolation plate 50 is a honeycomb vibration isolation plate. Holes are dug on the surface of the honeycomb vibration isolation structure to facilitate changing the stiffness of the resonance system by adjusting the spring expansion amount of the resonance adjuster.

[0082] When the vibration energy is transmitted to the honeycomb vibration isolation structure, the vibration is continuously reflected and scattered between the honeycomb units, extending the vibration propagation path and increasing the energy loss. The honeycomb units produce elastic deformation during the vibration process, resist the vibration through the elastic restoring force, change the vibration direction and amplitude, and achieve an efficient vibration isolation effect by reducing the vibration energy of the equipment.

[0083] Among them, the honeycomb vibration isolation plate includes a housing, and a honeycomb structure is arranged inside the housing. The housing is made of one of stainless steel and carbon steel materials, and the honeycomb structure is made of one of rubber and polyurethane foam materials.

[0084] See Figure 6 , the present invention provides a manufacturing method for a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer, including the following steps:

[0085] Step S1, determine the linear positive stiffness of the load-bearing spring according to the static load borne by the vibration isolator;

[0086] Step S2, determine the nonlinear negative stiffness according to the linear positive stiffness, and determine the air spring stiffness and the inclination angle;

[0087] Step S3, conduct a vibration test on the distribution transformer, and design the stiffness and mass parameters of the resonance adjuster according to the equipment vibration frequency;

[0088] Step S4, assemble the load-bearing spring, the air spring and the resonance adjuster.

[0089] In step S3, by changing the stiffness and mass of the resonance adjustable system, the natural frequency of the resonance system is further changed. Through precise adjustment, the natural frequency of the resonance system is matched with the equipment vibration frequency, and the resonance adjustable spring system enters the resonance state, canceling the equipment vibration energy and reducing the equipment vibration amplitude.

[0090] The specific installation method of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer provided by the present invention is as follows: precisely place the vibration isolator at a predetermined position at the bottom of the distribution transformer, select a suitable nut, at the welding points calculated on the surface of the vibration isolator, use professional welding equipment, strictly control the current, voltage and welding duration, and perform precise welding operations to ensure the firm connection between the nut and the vibration isolator. At the same time, precisely align the channel steel at the bottom of the distribution transformer so that the holes in the channel steel are in perfect alignment with the nuts welded on the vibration isolator, slowly pass the bolts through the holes in the channel steel and screw them into the nuts, and use a torque wrench to evenly tighten them diagonally in sequence according to the specified torque value to ensure the firm installation of the vibration isolator and lay a solid foundation for effectively exerting the vibration reduction effect.

[0091] The present invention adopts a parallel positive and negative stiffness structure to achieve quasi-zero stiffness characteristics at the static equilibrium position. Reasonable design of the quasi-zero stiffness vibration isolator can achieve the effect of low-frequency vibration isolation, and at the same time can provide sufficient bearing capacity to maintain the stability of the vibration isolation system.

[0092] The present invention combines the multi-stage stiffness coupling of the positive and negative stiffness structure with the dynamic tuning mechanism of the resonant adjustable system, and realizes the efficient isolation of low-frequency vibration through the cooperative action of multiple springs, providing a solution with a compact structure, stable performance and controllable cost for the low-frequency vibration control of heavy equipment such as distribution transformers, meeting the development needs of the smart grid for the environmental friendliness of equipment, and having broad application prospects.

[0093] The quasi-zero stiffness low-frequency vibration isolator of the present invention, which has high bearing capacity, broadband vibration isolation performance and structural compactness, has important engineering significance for improving the environmental friendliness of distribution facilities.

[0094] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. A quasi-zero stiffness low-frequency vibration isolator for a distribution transformer, characterized in that, Comprising: A housing, the housing includes an upper vibration isolator housing and a lower vibration isolator housing, and a first fixing member and a second fixing member are arranged inside the upper vibration isolator housing and the lower vibration isolator housing; Load-bearing springs, used to connect the upper vibration isolator housing and the lower vibration isolator housing, including a first load-bearing spring and a second load-bearing spring. The first ends of the first load-bearing spring and the second load-bearing spring are respectively connected to the bottom inside the lower vibration isolator housing, and the second ends of the first load-bearing spring and the second load-bearing spring are respectively connected to the inside of the upper vibration isolator housing; A resonance adjuster, used to adjust the vibration frequency to be in a resonance state with the equipment vibration; Air springs, used to connect the resonance adjuster with the upper vibration isolator housing and the lower vibration isolator housing.

2. The quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 1, wherein The air springs include a first air spring, a second air spring, a third air spring, and a fourth air spring. The first ends of the first air spring and the second air spring are connected to the inside of the upper vibration isolator housing, the second ends of the first air spring and the second air spring are connected to the resonance adjuster, the first ends of the third air spring and the fourth air spring are connected to the bottom of the lower vibration isolator housing, and the second ends of the third air spring and the fourth air spring are connected to the resonance adjuster.

3. The quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 1, wherein The resonance adjuster includes: A sleeve, a spring connection plate is arranged inside the sleeve, and a third fixing member for connecting the air spring is arranged on the outside of the sleeve; An upper spring, arranged at the upper end of the spring connection plate and connected to the spring connection plate; A lower spring, arranged at the lower end of the spring connection plate and connected to the spring connection plate; An end cap, arranged on the upper side of the upper spring and connected to the upper spring.

4. The quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 3, characterized in that, The upper spring and the lower spring are tower springs, and the bottom of the tower of the upper spring and the bottom of the tower of the lower spring are respectively connected to the upper side and the lower side of the spring connection plate; the top of the tower of the upper spring is embedded in the end cap and connected to the end cap.

5. A quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 1, characterized in that, An adjustment screw hole is arranged on the upper side of the upper vibration isolator housing, and an end cap is arranged in the adjustment screw hole.

6. The quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 1, wherein The air springs and the first fixing member, the second fixing member, and the third fixing member are in a hinged structure.

7. A quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 1, characterized in that, An anti-vibration plate is further arranged on the upper side of the upper vibration isolator housing, and the anti-vibration plate is a honeycomb anti-vibration plate.

8. A quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 7, characterized in that The honeycomb anti-vibration plate includes a housing, a honeycomb structure is arranged inside the housing, the housing is one of stainless steel and carbon steel materials, and the honeycomb structure is one of rubber and polyurethane foam materials.

9. The quasi-zero stiffness low-frequency vibration isolator for a distribution transformer according to claim 1, wherein The upper vibration isolator housing and the lower vibration isolator housing are made of one of stainless steel, carbon steel, and aluminum alloy.

10. A manufacturing method of a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer, characterized in that, Adopting a quasi-zero stiffness low-frequency vibration isolator for a distribution transformer as described in any one of claims 1-9, including the following steps: Determine the linear positive stiffness of the load-bearing spring according to the static load borne by the vibration isolator; Determine the non-linear negative stiffness according to the linear positive stiffness, and determine the stiffness and inclination angle of the air spring; Conduct a vibration test on the distribution transformer, and design the stiffness and mass parameters of the resonance adjuster according to the vibration frequency of the equipment; Assemble the load-bearing spring, the air spring, and the resonance adjuster.

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