Low-noise electromagnetic shock absorber and noise reduction method

Abstract

The invention relates to the technical field of noise reduction for shock absorbers, in particular to a low-noise electromagnetic shock absorber and a noise reduction method. The low-noise electromagnetic shock absorber comprises a push rod, a ball screw nut and a ball screw, the ball screw nut and the ball screw are in threaded engagement, the low-noise electromagnetic shock absorber further comprises a noise reduction cylindrical shell, a center hole is formed in the center of the noise reduction cylindrical shell, and the end, fixedly connected with the ball screw nut, of the push rod is arranged in the center hole in a sliding mode; the noise reduction column shell comprises an inner noise reduction column shell body and an outer noise reduction column shell body, a plurality of counter bores are formed in the outer wall face of the inner noise reduction column shell body and communicated with the center hole through round through holes, grooves corresponding to the counter bores are formed in the inner wall face of the outer noise reduction column shell body, and the grooves and the counter bores form a cavity. And an elastic film layer is arranged between the inner noise reduction cylindrical shell and the outer noise reduction cylindrical shell. Noise can be reduced through the local resonance effect, so that the effects of noise elimination and noise reduction are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of noise reduction for vibration dampers, in particular to a low-noise electromagnetic vibration damper and a noise reduction method. Background Art

[0002] The existing ball screw electromagnetic shock absorber has good response characteristics, high positioning accuracy, small radial geometric dimensions, and slightly longer axial dimensions, but poor impact resistance. When subjected to impact, it is accompanied by a more serious noise problem, especially when the screw rod performs reversing motion at both ends of the working stroke, it is often accompanied by a relatively high-frequency noise. In addition, during the working process, the screw rod inside the electromagnetic shock absorber will generate different noise conditions at different working strokes due to different working conditions.

[0003] When facing the noise inside the structure, the existing sound absorption structures mostly add sound absorption materials inside the structure or open tiny perforations inside the structure to achieve the sound absorption effect. Among them, the cost of sound absorption materials is relatively high, and a certain sound absorption effect can only be achieved when the sound absorption structure is of the same scale as the noise wavelength; the sound absorption effect of micro-perforated silencers is general and the actual application range of sound absorption frequency is very limited, and the small holes may be blocked during the application process.

[0004] Existing sound-absorbing structures designed using the Helmholtz resonance principle often design very complex resonant cavity structures inside the structure. When the sound source is inside the structure, if you want to design a localized resonant structure inside the overall structure, you need to dig holes inside the column shell to form a cavity structure. The cavity structure is usually composed of a cavity structure with irregular internal and external volumes. The irregular cavity in this structure is difficult to process and can usually only be achieved through 3D printing. Its specific production is difficult to put into practical applications. Summary of the invention

[0005] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and propose a low-noise electromagnetic vibration absorber and a noise reduction method, which can reduce noise through the local resonance effect to achieve the effect of silencing and noise reduction.

[0006] The technical solution of the present invention is: a low-noise electromagnetic vibration absorber, comprising a push rod, a ball screw nut, and a ball screw, wherein the ball screw nut and the ball screw are threadedly engaged with each other, and further comprising a noise reduction column housing, the center of which is provided with a center hole, and one end of the push rod fixedly connected to the ball screw nut is slidably arranged in the center hole;

[0007] The noise reduction column shell includes an inner noise reduction column shell and an outer noise reduction column shell. The outer wall surface of the inner noise reduction column shell is provided with a plurality of countersunk holes, which are connected with the central hole through a circular through hole. The inner wall surface of the outer noise reduction column shell is provided with grooves corresponding to the countersunk holes, and the grooves and the countersunk holes form a cavity.

[0008] An elastic film layer is arranged between the inner noise reduction column shell and the outer noise reduction column shell.

[0009] The present invention also includes a base box and a motor. One end of the noise reduction column shell is fixedly connected to the base box, and the other end is open. One end of the push rod extends into the noise reduction column shell through the opening. A joint is fixed to the end of the push rod located outside the noise reduction column shell.

[0010] One end of the ball screw nut is fixedly connected to the push rod, and the other end of the ball screw nut is fixed with a guide slider, and the guide slider is slidably connected to the inner wall of the noise reduction column shell;

[0011] The end of the push rod connected to the ball screw nut is provided with a hole, one end of the ball screw is rotatably arranged in the hole of the push rod, and the other end of the ball screw is located in the base box and is connected to the motor transmission;

[0012] The transmission components between the ball screw and the motor are arranged in the base box;

[0013] The transmission component comprises a first pulley fixedly connected to the end of the ball screw, a second pulley fixedly connected to the end of the motor shaft, and a synchronous belt for realizing transmission connection between the first pulley and the second pulley.

[0014] A base frame is fixed on one side of the base box facing the noise reduction column housing, and the ball screw passes through the base frame;

[0015] A bearing seat sleeve is fixed on the base frame, a round flange ball screw bearing is arranged in the bearing seat sleeve, and the ball screw passes through the round flange ball screw bearing and is fixedly connected to the round flange ball screw bearing.

[0016] The inner noise reduction column shell is cylindrical, a center hole is provided at the center of the inner noise reduction column shell, and the inner noise reduction column shell is fixedly connected to the base box;

[0017] Several circular countersunk holes are arranged at intervals on the outer wall surfaces at both ends of the inner noise reduction column shell, and several square countersunk holes are arranged at intervals on the outer wall surface of the middle part of the inner noise reduction column shell. The number of square countersunk holes is less than the number of circular countersunk holes at either end, and the area of ​​the circular countersunk holes is smaller than the area of ​​the square countersunk holes.

[0018] The outer noise reduction column shell includes two semi-cylindrical outer shells, and connecting plates are respectively fixed to the two side walls of the outer shells along the circumferential direction. The corresponding connecting plates of the outer shells on both sides are fixedly connected by bolts, and the inner noise reduction column shell is clamped and fixed inside the outer noise reduction column shell.

[0019] The elastic film layer is in the shape of an annular cylinder.

[0020] The cylindrical through hole and the countersunk hole on the inner noise reduction column shell, the groove on the outer noise reduction column shell, and the elastic film layer located between the countersunk hole and the groove together constitute a Helmholtz cavity structure of the coupling film.

[0021] The present invention also includes a noise reduction method for the above-mentioned low-noise electromagnetic vibration absorber, comprising the following steps:

[0022] S1. Connect the low-noise electromagnetic vibration absorber to the object to be damped. When the object to be damped vibrates, thread engagement occurs between the ball screw nut and the ball screw, which suppresses the rotation of the ball screw and thus achieves a vibration reduction effect.

[0023] S2. Noise is generated during the cooperation between the ball screw nut and the ball screw. Through the Helmholtz resonance cavity coupling film structure formed between the inner noise reduction column shell and the outer noise reduction column shell, when noise is generated in the center hole, the noise is reduced through the local resonance effect during the process of noise transmission to the outside.

[0024] When the ball screw nut in the center hole and the ball screw produce noise during the process of matching, the noise will be transmitted from the sound source to the outside, and the noise will be emitted from the small hole on the inner noise reduction column shell into the Helmholtz resonance cavity structure of the coupling film composed of the outer noise reduction column shell, the inner noise reduction column shell and the elastic film layer;

[0025] When the sound wave propagates through the Helmholtz resonance cavity structure coupled with the elastic film, the elastic film layer couples with the air in the cavity to generate a resonant frequency. The sound wave energy at the resonant frequency will be dissipated. The energy of the sound wave causes the air and the elastic film layer to resonate. Part of the sound wave energy is converted into the kinetic energy of the vibration of the elastic film layer and the vibration of the air. The other part of the sound wave energy is converted into heat dissipation through the friction between the air in the cavity and the elastic film layer, and the friction between the air and the cavity wall, thereby achieving noise reduction.

[0026] Helmholtz resonator resonant frequency f h and the film resonance frequency f t The coupling generates a new resonant frequency, where the resonant frequency of the Helmholtz resonator is f h for:

[0027]

[0028] Wherein, c is the speed of sound, V is the volume of the cylindrical cavity or the square cavity, l is the length of the circular through hole, S is the cross-sectional area of ​​the circular through hole, and K is the acoustic correction coefficient. K of the square cavity is generally 0.85-1, and K of the circular cavity is generally 0.95-1.

[0029] The film resonance frequency f of the elastic film layer in the Helmholtz resonant cavity t for:

[0030]

[0031] Among them, ρ is the density of the film; c is the speed of sound; m is the mass per unit area of ​​the film; L is the distance from the elastic film layer to the circular through hole; k is the elastic stiffness of the film.

[0032] Compared with the Helmholtz resonant cavity structure at the two ends and the Helmholtz resonant cavity structure at the middle, l and S of the two resonant cavity structures are the same, the volumes of the cylindrical cavities at the two ends and the square cavity at the middle are different, and the volume V1 of the cylindrical cavity formed by the circular countersunk hole is smaller than the volume V2 of the square cavity formed by the square countersunk hole;

[0033] The silencing frequency range generated by the silencing structure at V1 is higher than that generated at V2. The Helmholtz resonance cavity structures at both ends are for the high-frequency noise generated by the electromagnetic shock absorber when the two ends are switched, and the Helmholtz resonance cavity structure in the middle is for the low-frequency noise generated by the ball screw during operation.

[0034] The beneficial effects of the present invention are:

[0035] (1) The present invention can achieve the purpose of reducing noise while reducing vibration, thereby reducing the noise propagation outward, thereby achieving the purpose of reducing noise and absorbing sound;

[0036] (2) The present application forms a Helmholtz resonant cavity structure in the noise reduction column shell, which can achieve noise reduction at a sub-wavelength size. The implementation method is simple and does not require additional sound-absorbing materials. It also avoids the disadvantage of insufficient application frequency range of the micro-perforated structure. Especially when dealing with lower-frequency noise, its compact structure has the advantage of being very prominent, and can achieve effective sound absorption effect for low-frequency noise.

[0037] (3) Different types of Helmholtz resonance cavities are arranged at different positions of the noise reduction column shell. Helmholtz resonance cavities of different sizes have different common sound absorption frequency ranges, thereby achieving targeted absorption of noise of specific frequencies at different positions;

[0038] (4) Helmholtz resonance structure, with its unique local resonance silencing mechanism, can achieve silencing and noise reduction at sub-wavelength size. When dealing with lower frequency noise, its compact structure is particularly advantageous;

[0039] (5) The Helmholtz resonance cavity structure proposed in the present application is easy to implement and can be designed and processed for different shock absorber structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 It is a schematic diagram of the structure of the present invention;

[0041] Figure 2 It is a cross-sectional structural schematic diagram of the present invention;

[0042] Figure 3 It is a schematic diagram of the connection structure between the ball screw and the round flange ball screw bearing;

[0043] Figure 4 It is a schematic diagram of the structure of one end of the ball screw;

[0044] Figure 5 It is a structural schematic diagram of the inner noise reduction column shell;

[0045] Figure 6 It is a schematic diagram of the structure of the outer shell of the outer noise reduction column shell;

[0046] Figure 7 is a schematic diagram of the structure of the outer elastic film layer;

[0047] Figure 8 is a schematic diagram of a partial structure of a Helmholtz resonant cavity in the present application;

[0048] Fig. 9 It is a schematic diagram of the structure in which the push rod moves to the top in this application;

[0049] Fig.10 It is a schematic diagram of the structure in which the push rod in this application moves to the lowest end.

[0050] In the figure: 1 joint, 2 bolt, 3 push rod, 4 outer noise reduction column shell, 401 outer shell; 402 connecting plate; 403 circular groove; 404 square groove; 6 motor, 7 base box, 8 inner noise reduction column shell, 801 connecting flange; 802 circular through hole; 803 circular countersunk hole; 804 square countersunk hole; 9 elastic film layer, 10 ball screw nut, 11 guide slider, 12 ball screw, 13 round flange ball screw bearing, 14 base frame, 15 first pulley, 17 synchronous belt, 18 second pulley, 19 motor shaft, 20 bearing sleeve. DETAILED DESCRIPTION

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0052] In the following description, specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0053] like Figure 1 and Figure 2As shown, the low-noise electromagnetic vibration absorber described in the present invention includes a noise reduction column shell, a base box 7, and a motor 6. One end of the noise reduction column shell is open, and the other end is connected to the motor 6 through the base box 7. A center hole is provided in the center of the noise reduction column shell along its axial direction. The push rod 3 passes through the opening at the end of the noise reduction column shell and is slidably arranged in the center hole of the noise reduction column shell. A sealing ring is provided at the contact point between the push rod 3 and the end of the noise reduction column shell to ensure the sealing between the push rod 3 and the noise reduction column shell. One end of the push rod 3 located outside the noise reduction column shell is fixedly connected to the joint 1 through a bolt 2, and one end of the push rod 3 located in the center hole of the noise reduction column shell is fixedly connected to the ball screw nut 10 through a bolt. One end of the ball screw nut 10 is fixedly connected to the push rod 3, and the other end of the ball screw nut 10 is fixedly connected to the guide slider 11 through a pin. The ball screw nut 10 is slidably arranged in the center hole of the noise reduction column shell.

[0054] The annular inner surface of the ball screw nut 10 is threadedly engaged with the ball screw 12. In this embodiment, a slider is fixed to the outer wall of the guide slider 11, and a guide groove is provided on the inner wall of the corresponding noise reduction column shell. The slider can slide in the guide groove, thereby ensuring that the ball screw nut 10 can only make linear motion relative to the ball screw, but cannot rotate circumferentially. The end of the push rod 3 connected to the ball screw nut 10 is provided with a hole, one end of the ball screw 12 is set in the hole inside the push rod 3, and the other end is set in the base box 7. While ensuring that the screw rod rotates inside the push rod, the push rod and the ball screw nut make reciprocating linear motion together.

[0055] The base box 7 is in a cavity shape, and a base frame 14 is fixed to the end surface of the base box 7 facing the noise reduction column shell. One end of the ball screw 12 is rotatably arranged in the blind hole of the push rod, and the other end of the ball screw 12 is arranged in the base box 7 and is connected to the motor 6. Through the ball screw 12, the reciprocating linear motion of the ball screw nut is converted into the rotational motion of the ball screw 1, and the rotation is transmitted to the motor 6, and the motor 6 generates electricity.

[0056] The ball screw 12 passes through the base frame 14, and a bearing sleeve 20 is fixed on the base frame 14. Figure 3 As shown, a round flange ball screw bearing 13 is provided in the bearing seat sleeve 20, and the ball screw 12 passes through the round flange ball screw bearing 13, and the ball screw 12 is fixedly connected to the round flange ball screw bearing 13. A shaft shoulder is provided at the fixed connection between the ball screw 12 and the round flange ball screw bearing 13. After the ball screw 12 is matched with the round flange ball screw bearing 13 and passes through the inside of the bearing, the round flange ball screw bearing 13 can constrain and fix the ball screw 1. A 13 is fixed at the center hole of the noise reduction column shell near the base box, and the round flange ball screw bearing 13 guides the ball screw 12.

[0057] The first pulley 15 is fixed to one end of the ball screw located in the base box 7. The end of the ball screw connected to the first pulley 15 is processed with a shoulder and a thread, so that the first pulley 15 is fixed to the end of the ball screw. Figure 4 A second pulley 18 is fixed to one end of the motor shaft 19 , and the second pulley 18 is also located in the base box 7 , and the first pulley 15 and the second pulley 18 are connected by a synchronous belt 17 .

[0058] The noise reduction column shell includes an outer noise reduction column shell 4 and an inner noise reduction column shell 8, and the outer noise reduction column shell 4 is located outside the inner noise reduction column shell 8. Figure 5 As shown, the inner noise reduction column shell 8 is cylindrical, and a center hole is provided in the center of the inner noise reduction column shell 8, and the ball screw nut 10 and the ball screw 12 are both arranged in the center hole. A connecting flange 801 is fixed to one end of the inner noise reduction column shell 8 facing the base box 7, and a fixed connection between the inner noise reduction column shell 8 and the base box 7 is achieved through the connecting flange 801.

[0059] A circular countersunk hole 803 and a square countersunk hole 804 are provided on the outer side wall of the inner noise reduction column shell 8. The circular countersunk hole 803 and the square countersunk hole 804 are respectively connected to the central hole of the inner noise reduction column shell 8 through a circular through hole 802. The circular through hole 802 is located at the center of the circular countersunk hole and the square countersunk hole. The size of the circular countersunk hole 803 is smaller than the size of the square countersunk hole 804, and the diameter of the circular through hole 802 is smaller than the diameter of the circular countersunk hole 803. The circular countersunk hole 803 is arranged at both side ends of the inner noise reduction column shell 8, and the square countersunk hole 804 is arranged in the middle of the inner noise reduction column shell 8.

[0060] In this embodiment, at both ends of the outer wall of the inner noise reduction column shell 8, three circles of circular countersunk holes 803 are spaced apart along the axial direction of the inner noise reduction column shell, and each circle of circular countersunk holes 803 includes a plurality of circular countersunk holes spaced apart along the radial direction of the inner noise reduction column shell. A plurality of square countersunk holes 804 are spaced apart evenly along the radial direction of the inner noise reduction column shell in the middle of the outer wall of the inner noise reduction column shell 8.

[0061] like Figure 6 As shown, the outer noise reduction column housing 4 in the present application is formed by connecting two semi-cylindrical outer shells 401. Connecting plates 402 are respectively fixed at the connection of the two outer shells, and the corresponding connecting plates 402 of the outer shells on both sides are fixedly connected by bolts, so that the inner noise reduction column housing 8 is clamped and fixed between the two outer shells 401.

[0062] Circular grooves 403 corresponding to the circular countersunk holes are provided at both ends of the inner side wall of the outer noise reduction column housing 4. The position and diameter of the circular groove 403 completely correspond to the position and diameter of the circular countersunk hole 803. Therefore, a cylindrical cavity is formed between the circular groove 403 and the circular countersunk hole 803. A square groove 404 corresponding to the square countersunk hole is provided in the middle of the inner side wall of the outer noise reduction column housing 4. The position and length and width of the square groove 404 completely correspond to the position and length and width of the square countersunk hole 804. Therefore, a square cavity is formed between the square groove 404 and the square countersunk hole 804.

[0063] An elastic film layer 9 is provided between the inner noise reduction column shell 8 and the outer noise reduction column shell 4. Figure 7 As shown, the elastic film layer 9 is cylindrical and made of elastic material. After the inner noise reduction column shell 8 is fixedly installed on the base box 7, a layer of elastic film layer 7 is put on the outer side of the inner noise reduction column shell 8, and after the holes on the two outer shells 401 are aligned with the holes on the inner noise reduction column shell 8, the two outer column shells are tightly connected by screws to form a complete noise reduction column shell. The outer noise reduction column shell 4, the inner noise reduction column shell 8 and the elastic film layer 9 are closely matched to form a Helmholtz resonance cavity structure of a coupled elastic film. At the same time, the elastic film layer 9 is clamped between the inner noise reduction column shell 8 and the outer noise reduction column shell 4, which can also play a role in sealing and preventing noise leakage.

[0064] The present application also includes a noise reduction method for the above-mentioned electromagnetic vibration absorber, which specifically includes the following steps.

[0065] In the first step, the joint 1 and the base box 7 of the vibration damper are connected to the object to be damped. When the object to be damped vibrates, the push rod 3 slides in the center hole of the noise reduction column shell and drives the ball screw nut 10 to move back and forth in the center hole. The reciprocating motion of the ball screw nut 10 is converted into the rotation of the ball screw 12 through the thread engagement between the ball screw nut 10 and the ball screw 12 and the limiting guiding action of the guide slider 11.

[0066] During the rotation of the ball screw 12, the motor shaft 19 is driven to rotate through the pulley and the synchronous belt. The rotation of the motor will generate an induced electromotive force. When a closed circuit is formed between the two terminals of the motor, an induced current will be generated in the circuit under the action of the induced voltage. The induced current can make the motor have a torque that hinders relative motion. The torque is transmitted from the motor shaft to the ball screw through the synchronous belt, inhibiting the rotation of the ball screw, thereby playing a vibration reduction role.

[0067] In the second step, a large noise will be generated during the cooperation between the ball screw nut and the ball screw. Through the Helmholtz cavity structure of the coupled elastic film formed between the inner noise reduction column shell 8 and the outer noise reduction column shell 4 in the present application, when noise is generated in the center hole, the noise is reduced by the local resonance effect during the process of noise transmission to the outside, so as to achieve the effect of noise elimination.

[0068] During the transmission of noise from the sound source to the outside, the noise will be emitted from the small holes on the inner noise reduction column shell into the Helmholtz resonance cavity structure composed of the outer noise reduction column shell 4, the inner noise reduction column shell 8 and the elastic film layer 9, which is a coupled elastic film. When the sound wave propagates through the Helmholtz resonance cavity structure of the coupled elastic film, the elastic film layer 9 couples with the air in the cavity to generate multiple resonant frequencies, and the sound wave energy at the resonant frequency will be dissipated. The energy of the sound wave causes the air and the elastic film layer 9 to resonate, and part of the sound wave energy is converted into the kinetic energy of the vibration of the elastic film layer and the vibration of the air, and the other part of the sound wave energy is converted into heat dissipation through the friction between the air in the cavity and the elastic film layer 9, and the friction between the air and the cavity wall, thereby achieving the purpose of noise reduction.

[0069] Helmholtz resonator resonant frequency f h and the film resonance frequency f t The coupling broadens the low-frequency sound absorption band, and can achieve a lower frequency and wider range of sound absorption effects. The resonant frequency f of the Helmholtz resonator h for:

[0070]

[0071] Among them, c is the speed of sound, V is the volume of the cylindrical cavity or the square cavity, l is the length of the circular through hole, S is the cross-sectional area of ​​the circular through hole, and K is the acoustic correction coefficient. The K of the square resonance cavity is generally between 0.85 and 1, and the K of the circular resonance cavity is generally between 0.95 and 1.

[0072] like Figure 8 As shown, there is an elastic film material in the Helmholtz resonance cavity. The film itself has rigidity and mass, and its film resonance frequency f t for:

[0073]

[0074] Among them, ρ is the density of the film; c is the speed of sound; m is the mass per unit area of ​​the film; L is the distance from the elastic film layer to the circular through hole; k is the elastic stiffness of the film.

[0075] The third step is that noise will be generated during the cooperation between the ball screw and the ball screw nut, and the noise generated by the sound source at different working positions will be different. Fig. 9 The figure shows the working state when the push rod runs to the top of the noise reduction column shell. Fig.10 This is the working state when the push rod runs to the bottom of the noise reduction column housing. At these two positions, a high-frequency and loud noise is generated between the ball screw and the ball screw nut.

[0076] Therefore, the Helmholtz cavities set at the two side ends of the noise reduction column shell are relatively small in size and large in number, and sound absorption treatment is performed on the higher-frequency noise at both ends. At the middle position of the noise reduction column shell, the noise frequency generated between the ball screw and the ball screw nut is relatively low. Therefore, in this application, a relatively large Helmholtz cavity structure is set in the middle of the noise reduction column shell to achieve absorption of small-frequency noise, thereby achieving effective absorption of noise of different frequencies generated at different positions.

[0077] Compared with the Helmholtz resonant cavity structure at the two ends and the Helmholtz resonant cavity structure in the middle, the l and S of the two resonant cavity structures are the same, the volume of the cylindrical cavity at the two ends and the square cavity in the middle is different, and the corresponding Helmholtz resonator resonant frequency f h Different. The volume V1 of the cylindrical cavity formed by the circular countersunk hole 803 is smaller than the volume V2 of the square cavity formed by the square countersunk hole 804, so the sound absorption frequency range finally generated by its coupling structure is also different, and the sound absorption frequency range generated by the sound absorption structure at V1 is higher than the sound absorption frequency range generated at V2. Therefore, the circular countersunk heads at both ends are for the high-frequency noise generated by the electromagnetic shock absorber when the two ends are switched, and the square countersunk head in the middle is for the lower-frequency noise generated by the ball screw during operation.

[0078] The low-noise electromagnetic vibration absorber provided by the present invention is introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and core ideas of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the present invention. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined in this article can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown in this article, but will conform to the widest range consistent with the principles and novel features disclosed in this article.

Claims

1. A low-noise electromagnetic vibration absorber, comprising a push rod, a ball screw nut, and a ball screw, wherein the ball screw nut and the ball screw are threadedly engaged with each other, characterized in that: It also includes a noise reduction column housing, the center of which is provided with a center hole, and one end of the push rod fixedly connected to the ball screw nut is slidably arranged in the center hole; The noise reduction column shell includes an inner noise reduction column shell and an outer noise reduction column shell. The outer wall surface of the inner noise reduction column shell is provided with a plurality of countersunk holes, which are connected with the central hole through a circular through hole. The inner wall surface of the outer noise reduction column shell is provided with grooves corresponding to the countersunk holes, and the grooves and the countersunk holes form a cavity. An elastic film layer is arranged between the inner noise reduction column shell and the outer noise reduction column shell.

2. The low-noise electromagnetic vibration absorber according to claim 1, characterized in that: It also includes a base box and a motor, one end of the noise reduction column shell is fixedly connected to the base box, and the other end is open, one end of the push rod extends into the noise reduction column shell through the opening, and a joint is fixed on the end of the push rod located outside the noise reduction column shell; One end of the ball screw nut is fixedly connected to the push rod, and the other end of the ball screw nut is fixed with a guide slider, and the guide slider is slidably connected to the inner wall of the noise reduction column shell; A blind hole is provided at the end of the push rod connected to the ball screw nut, one end of the ball screw is rotatably arranged in the blind hole of the push rod, and the other end of the ball screw is located in the base box and is transmission-connected to the motor; The transmission components between the ball screw and the motor are arranged in the base box.

3. The low-noise electromagnetic vibration absorber according to claim 2, characterized in that: The transmission component comprises a first pulley fixedly connected to the end of the ball screw, a second pulley fixedly connected to the end of the motor shaft, and a synchronous belt for realizing transmission connection between the first pulley and the second pulley.

4. The low-noise electromagnetic vibration absorber according to claim 1, characterized in that: A base frame is fixed on one side of the base box facing the noise reduction column housing, and the ball screw passes through the base frame; A bearing seat sleeve is fixed on the base frame, a round flange ball screw bearing is arranged in the bearing seat sleeve, and the ball screw passes through the round flange ball screw bearing and is fixedly connected to the round flange ball screw bearing.

5. The low-noise electromagnetic vibration absorber according to claim 1, characterized in that: The inner noise reduction column shell is cylindrical, a center hole is provided at the center of the inner noise reduction column shell, and the inner noise reduction column shell is fixedly connected to the base box; Several circular countersunk holes are arranged at intervals on the outer wall surfaces at both ends of the inner noise reduction column shell, and several square countersunk holes are arranged at intervals on the outer wall surface of the middle part of the inner noise reduction column shell. The number of square countersunk holes is less than the number of circular countersunk holes at either end, and the volume of the square countersunk holes is greater than the volume of the circular countersunk holes.

6. The low-noise electromagnetic vibration absorber according to claim 1, characterized in that: The outer noise reduction column shell includes two semi-cylindrical outer shells, and connecting plates are respectively fixed to the two side walls of the outer shells along the circumferential direction. The corresponding connecting plates of the outer shells on both sides are fixedly connected by bolts, and the inner noise reduction column shell is clamped and fixed inside the outer noise reduction column shell.

7. The low-noise electromagnetic vibration absorber according to claim 1, characterized in that: The cylindrical through hole and the countersunk hole on the inner noise reduction column shell, the groove on the outer noise reduction column shell, and the elastic film layer located between the countersunk hole and the groove together constitute a Helmholtz resonance cavity structure of a coupled film.

8. A noise reduction method for a low-noise electromagnetic vibration absorber according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Connect the low-noise electromagnetic vibration absorber to the object to be damped. When the object to be damped vibrates, thread engagement occurs between the ball screw nut and the ball screw, which suppresses the rotation of the ball screw and thus achieves a vibration reduction effect. S2. Noise is generated during the cooperation between the ball screw nut and the ball screw. Through the Helmholtz resonance cavity coupling film structure formed between the inner noise reduction column shell and the outer noise reduction column shell, when noise is generated in the center hole, the noise is reduced through the local resonance effect during the process of noise transmission to the outside.

9. The method according to claim 8, characterized in that When the ball screw nut in the center hole and the ball screw produce noise during the process of matching, the noise will be transmitted from the sound source to the outside, and the noise will be emitted from the small hole on the inner noise reduction column shell into the Helmholtz resonance cavity structure of the coupling film composed of the outer noise reduction column shell, the inner noise reduction column shell and the elastic film layer; When the sound wave propagates through the Helmholtz resonance cavity structure coupled with the elastic film, the elastic film layer couples with the air in the cavity to generate a resonant frequency. The sound wave energy at the resonant frequency will be dissipated. The energy of the sound wave causes the air and the elastic film layer to resonate. Part of the sound wave energy is converted into the kinetic energy of the vibration of the elastic film layer and the vibration of the air. The other part of the sound wave energy is converted into heat dissipation through the friction between the air in the cavity and the elastic film layer, and the friction between the air and the cavity wall, thereby achieving noise reduction. Helmholtz resonator resonant frequency f h and the film resonance frequency f t The coupling generates a new resonant frequency, where the resonant frequency of the Helmholtz resonator is f h for: Wherein, c is the speed of sound, V is the volume of the cylindrical cavity or the square cavity, l is the length of the circular through hole, S is the cross-sectional area of ​​the circular through hole, K is the acoustic correction coefficient, and the value range of K when calculating the resonant frequency of the square cavity is 0.85-1, and the value range of K when calculating the resonant frequency of the circular cavity is 0.95-1; The film resonance frequency f of the elastic film layer in the Helmholtz resonant cavity t for: Among them, ρ is the density of the film; c is the speed of sound; m is the mass per unit area of ​​the film; L is the distance from the elastic film layer to the circular through hole; k is the elastic stiffness of the film.

10. The method according to claim 9, characterized in that Compared with the Helmholtz resonant cavity structure at the two ends and the Helmholtz resonant cavity structure at the middle, l and S of the two resonant cavity structures are the same, the volumes of the cylindrical cavities at the two ends and the square cavity at the middle are different, and the volume V1 of the cylindrical cavity formed by the circular countersunk hole is smaller than the volume V2 of the square cavity formed by the square countersunk hole; The silencing frequency range generated by the silencing structure at V1 is higher than that generated at V2. The Helmholtz resonance cavity structures at both ends are for the high-frequency noise generated by the electromagnetic shock absorber when the two ends are switched, and the Helmholtz resonance cavity structure in the middle is for the low-frequency noise generated by the ball screw during operation.

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