Damping dynamic vibration absorber with adjustable vibration absorption frequency

Abstract

The invention relates to the technical field of vibration reduction equipment, and provides a damping dynamic vibration absorber with adjustable vibration absorption frequency, which comprises a vibration isolator, a supporting platform, a first elastic piece, a first box body and a pair of rigidity adjusting mechanisms, the supporting platform is arranged on the vibration isolator, the first box body is connected with the supporting platform through the first elastic piece, and the rigidity adjusting mechanisms are arranged on the two sides of the first box body correspondingly; each rigidity adjusting mechanism comprises a second box body and a second elastic piece, the second box body is connected with the supporting platform, the second elastic piece is arranged in the second box body, one end of the second elastic piece penetrates through the second box body to be connected with the first box body, and the second elastic piece is in a compressed state. According to the dynamic vibration absorber with the adjustable vibration absorption frequency and the damping function, the combination of the positive stiffness and the negative stiffness is utilized, so that the dynamic vibration absorber with the adjustable vibration absorption frequency and the damping function has a high static stiffness value and a low dynamic stiffness value, and therefore low-frequency vibration can be effectively isolated.

Description

Technical Field

[0001] The invention relates to the technical field of vibration reduction equipment, and in particular to a dynamic vibration absorber with damping and adjustable vibration absorption frequency. Background Art

[0002] The rotating machinery of a ship is usually installed on a support platform. During operation, the vibration generated by the rotating machinery will be transmitted outward through the support platform, causing the connection parts to loosen. In severe cases, this vibration transmission may cause immeasurable economic losses. To solve this problem, the current technical means is to install a dynamic vibration absorber on the support platform to achieve a vibration reduction effect.

[0003] The working principle of a traditional dynamic vibration absorber is to adjust its natural frequency to be close to the excitation frequency of the main vibration system, utilize the resonance phenomenon, and use the energy transfer effect to reduce the vibration amplitude of the main vibration system. However, traditional dynamic vibration absorbers perform well in reducing high-frequency vibrations, but the vibration reduction effect on low-frequency vibrations is relatively poor. The main reason is that the vibration absorption frequency of the dynamic vibration absorber is directly proportional to its stiffness, while the overall deformation of the dynamic vibration absorber is inversely proportional to its stiffness. If a smaller stiffness is designed to reduce the vibration absorption frequency of the dynamic vibration absorber, although the vibration reduction ability of low-frequency vibrations can be improved, it will cause a larger overall deformation of the dynamic vibration absorber, and then a larger deformation space needs to be reserved, resulting in a reduction in space utilization. Based on this, providing a dynamic vibration absorber that can effectively isolate low-frequency vibrations has become an urgent problem to be solved in the industry. Summary of the invention

[0004] The invention provides a dynamic vibration absorber with adjustable vibration absorption frequency and damping, so as to solve the defect that the dynamic vibration absorber in the prior art has poor vibration reduction effect on low-frequency vibration.

[0005] The present invention provides a dynamic vibration absorber with damping and adjustable vibration absorption frequency, comprising: a vibration isolator, a supporting platform, a first elastic member, a first box, and a pair of stiffness adjustment mechanisms; the supporting platform is arranged on the vibration isolator, the first box is connected to the supporting platform through the first elastic member, and a pair of stiffness adjustment mechanisms are respectively arranged on both sides of the first box; each of the stiffness adjustment mechanisms comprises: a second box and a second elastic member, the second box is connected to the supporting platform, the second elastic member is arranged in the second box, one end of the second elastic member passes through the second box and is connected to the first box, wherein the second elastic member is in a compressed state.

[0006] According to a dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention, each of the stiffness adjustment mechanisms also includes a first telescopic structure, which is arranged in the second box body and connected to the second elastic member, and the first telescopic structure is used to adjust the pre-compression amount of the second elastic member.

[0007] According to a dynamic vibration absorber with adjustable vibration absorption frequency provided by the present invention, each of the stiffness adjustment mechanisms also includes a first baffle; the first baffle is arranged between the first telescopic structure and the second elastic member, the first baffle is connected to the first telescopic structure, and can move under the action of the first telescopic structure, and the second elastic member abuts against the first baffle.

[0008] According to a dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention, each of the stiffness adjustment mechanisms further includes a connecting rod, and two ends of the connecting rod are respectively connected to the first box body and the second elastic member.

[0009] According to a dynamic vibration absorber with adjustable vibration absorption frequency provided by the present invention, a plurality of partitions are provided in the first box body along the height direction and the width direction of the first box body to divide the space in the first box body into a plurality of cavities, each of the cavities is filled with liquid.

[0010] A dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention also includes a third box body, in which liquid is arranged, the third box body is connected to the first box body through a pipeline, and a pump is arranged on the pipeline, and the third box body is used to adjust the weight of the first box body; wherein each of the second boxes is telescopically connected to the supporting platform.

[0011] A dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention also includes a pair of second telescopic structures, and the two ends of each of the second telescopic structures are respectively connected to the supporting platform and the second box body, and the second telescopic structures are used to adjust the height of the second box body so that after the height of the first box body changes, the connecting rod is always in a horizontal state.

[0012] A dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention also includes a vibration acceleration sensor and a controller. The vibration acceleration sensor is arranged on the supporting platform, and the controller is used to control the pump to be turned off according to the vibration acceleration signal sent by the vibration acceleration sensor.

[0013] A dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention also includes a liquid level sensor, which is arranged in the first box body. The liquid level sensor is electrically connected to the controller, and the controller is used to control the pump to shut down according to the liquid level height detected by the liquid level sensor.

[0014] According to a dynamic vibration absorber with adjustable vibration absorption frequency provided by the present invention, the second box body is a metal damping structure.

[0015] The dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention has a high static stiffness value and a low dynamic stiffness value by arranging a first elastic member and a second elastic member, and making the second elastic member in a compressed state, and utilizing a combination of positive stiffness and negative stiffness, so that the dynamic vibration absorber with damping and adjustable vibration absorption frequency has a high static stiffness value and a low dynamic stiffness value, thereby being able to effectively isolate low-frequency vibrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a structural schematic diagram of a dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention.

[0018] Figure 2 yes Figure 1 Schematic diagram of the structure of the stiffness adjustment mechanism shown in FIG.

[0019] Reference numerals: 1. Support platform; 2. First elastic member; 3. First box; 31. Partition; 4. Vibration isolator; 5. Stiffness adjustment mechanism; 51. Second box; 52. Second elastic member; 53. First driver; 54. First baffle; 55. Second baffle; 56. Connecting rod; 57. First telescopic member; 61. Third box; 62. Pipeline; 63. Pump; 71. Second driver; 72. Second telescopic member; 81. Vibration acceleration sensor; 82. Controller; 83. Liquid level sensor. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Combine the following Figure 1 and Figure 2 The invention discloses a dynamic vibration absorber with adjustable vibration absorption frequency and damping.

[0022] like Figure 1 and Figure 2 As shown, in an embodiment of the present invention, a dynamic vibration absorber with damping and adjustable vibration absorption frequency comprises: a support platform 1, a first elastic member 2, a first box 3, a vibration isolator 4 and a pair of stiffness adjustment mechanisms 5. The support platform 1 is mounted on the base structure through the vibration isolator 4, and the rotating mechanism of the ship is mounted on the support platform 1. The first box 3 is connected to the support platform 1 through the first elastic member 2, and the first box 3 is filled with liquid. A pair of stiffness adjustment mechanisms 5 are respectively arranged on both sides of the first box 3. Each stiffness adjustment mechanism 5 comprises: a second box 51 and a second elastic member 52, the second box 51 is connected to the support platform 1, the second elastic member 52 is arranged in the second box 51, one end of the second elastic member 52 passes through the second box 51 and is connected to the first box 3, wherein the second elastic member 52 is in a compressed state.

[0023] Specifically, in this embodiment, the first box body 3 is connected to the support platform 1 through the first elastic member 2, the first box body 3 is in a suspended state, and the first elastic member 2 provides positive stiffness. The two second elastic members 52 on the left and right sides of the first box body 3 are both in a compressed state, providing negative stiffness in the vertical direction. Through the combination of the positive stiffness and negative stiffness of the three elastic members, a quasi-zero stiffness can be provided at the static equilibrium position of the first box body 3, that is, a larger static stiffness value and a smaller dynamic stiffness value are provided near the static equilibrium position of the first box body 3. The larger static stiffness value can ensure that the first box body 3 has a smaller deformation under the gravity of the liquid, and the smaller dynamic stiffness value can reduce the vibration absorption frequency of the dynamic vibration absorber and improve the low-frequency vibration absorption performance.

[0024] In the embodiment of the present invention, the first box 3 is elastically connected to the support platform 1, serving as the main structure of the dynamic vibration absorber. The natural frequency of the main structure is designed to be close to the excitation frequency of the main vibration system, and the purpose of transferring vibration energy is achieved through resonance, thereby reducing vibration, and no additional equipment is required, so that the dynamic vibration absorber has a simple structure and a small size, and does not need to occupy a larger space.

[0025] The dynamic vibration absorber with damping and adjustable vibration absorption frequency provided in an embodiment of the present invention, by setting a first elastic member and a second elastic member, and making the second elastic member in a compressed state, utilizes a combination of positive stiffness and negative stiffness, so that the dynamic vibration absorber with damping and adjustable vibration absorption frequency has a high static stiffness value and a low dynamic stiffness value, thereby being able to effectively isolate low-frequency vibrations.

[0026] In the embodiment of the present invention, the second box body 51 is a metal damping structure, which can suppress the vibration of the first box body 3 from being transmitted to the supporting platform 1 .

[0027] like Figure 2 As shown, in the embodiment of the present invention, each stiffness adjustment mechanism 5 also includes a first telescopic structure, which is arranged in the second box body 51 and connected to the second elastic member 52. The first telescopic structure is used to drive the second elastic member 52 to compress, so as to adjust the pre-compression amount of the second elastic member 52, thereby changing the negative stiffness characteristic curve of the dynamic vibration absorber, so that the dynamic vibration absorber can absorb vibration under different working conditions. In an optional embodiment of the present invention, the first telescopic structure can be a device capable of telescopic movement such as a hydraulic cylinder, a pneumatic cylinder, and an electric cylinder; in another optional embodiment of the present invention, the first telescopic structure includes: a first driver 53 and a first telescopic member 57, the two ends of the first telescopic member 57 are respectively connected to the inner wall of the second box body 51 and the first driver 53, the first driver 53 is connected to the second elastic member 52, and the first driver 53 drives the first telescopic member 57 to extend when moving, thereby adjusting the pre-compression amount of the second elastic member 52. Optionally, the first driver 53 can be a linear motor.

[0028] Optionally, the first elastic member 2 and the second elastic member 52 may be springs.

[0029] like Figure 2 As shown, in the embodiment of the present invention, each stiffness adjustment mechanism 5 further includes a first baffle 54. The first baffle 54 is disposed between the first driver 53 and the second elastic member 52, and the first baffle 54 is connected to the first driver 53. When the first driver 53 moves, it can push the first baffle 54 to move in a direction close to the first box body 3, thereby adjusting the pre-compression amount of the second elastic member 52.

[0030] In an optional embodiment of the present invention, the second box 51 can be a structure with an open top surface, an open front side surface, or an open rear side surface to place the first telescopic member 57, the first driver 53, the first baffle 54, and the second elastic member 52, and one end of the second elastic member 52 passes through the plate surface of the second box 51 and is connected to the first box 3; in another optional embodiment, the end of the second box 51 adjacent to the first box 3 is an open end, so that the first telescopic member 57, the first driver 53, the first baffle 54, and the second elastic member 52 are placed in the second box 51 through the open end. The open end is provided with a second baffle 55, and the second elastic member 52 passes through the second baffle 55 and is connected to the first box 3.

[0031] like Figure 2 As shown, each stiffness adjustment mechanism 5 further includes a connecting rod 56, and two ends of the connecting rod 56 are respectively connected to the first box body 3 and the second elastic member 52.

[0032] like Figure 1 As shown, in an embodiment of the present invention, a plurality of partitions 31 are provided in the first box body 3 along the height direction and the width direction of the first box body 3 to divide the space in the first box body 3 into a plurality of cavities, each of which is filled with liquid. In this embodiment, the first box body 3 is divided into a plurality of small boxes, and the height of the liquid in each small box is relatively shallow. When the first box body 3 swings, the liquid is more likely to slosh in each small box and collide with the wall of the small box to generate liquid damping. Compared with the traditional dynamic vibration absorber which only has mass and stiffness effects, the dynamic vibration absorber with damping and adjustable vibration absorption frequency provided in the embodiment of the present invention utilizes the sloshing effect of a plurality of shallow liquid boxes to provide a damping factor, and utilizes the characteristic that damping can greatly reduce the vibration peak at the resonance frequency, thereby realizing vibration reduction of the support platform 1.

[0033] like Figure 1 As shown, in an embodiment of the present invention, the dynamic vibration absorber with adjustable vibration absorption frequency further includes a third box 61. Liquid is arranged in the third box 61, and the third box 61 is connected to the first box 3 through a pipeline 62. A pump 63 is arranged on the pipeline 62, and the pump 63 can pump the liquid in the third box 61 into the first box 3 to adjust the weight of the first box 3. In this embodiment, each second box 51 is telescopically connected to the support platform 1, so that when the height of the first box 3 changes, the height of the second box 51 changes accordingly.

[0034] Specifically, in the prior art, the mass and stiffness of the traditional dynamic vibration absorber are fixed, and they perform well under specific working conditions and a single frequency, but cannot meet the vibration reduction requirements under various working conditions. In this embodiment, when the operating conditions of the rotating mechanism change, the pump 63 is turned on, and the pump 63 pumps the liquid in the third box 61 into the first box 3, so that the weight of the first box 3 changes, so as to change the natural frequency of the dynamic vibration absorber, thereby reducing vibrations of different frequencies. In this embodiment, the stiffness of the first box 3 is provided by the first elastic member 2 and the two second elastic members 52, and the mass of the first box 3 is composed of the shell weight of the first box 3 and the mass of the liquid in the first box 3 (the weight of the partition 31 can be ignored). In this way, the decoupling of stiffness and mass can be achieved, so that the resonant frequency of the dynamic vibration absorber shows a monotonically changing relationship with the mass of the liquid, and there are no other extreme values ​​except the end points within a certain parameter range, so that dynamic vibration absorption within a wide frequency band can be achieved.

[0035] Optionally, in an embodiment of the present invention, the dynamic vibration absorber with damping and adjustable vibration absorption frequency also includes a second telescopic structure, both ends of which are respectively connected to the supporting platform 1 and the second box 51, and the second telescopic structure is used to adjust the height of the second box 51, so that after the height of the first box 3 changes, the height of the second box 51 changes accordingly, thereby keeping the connecting rod 56 in a horizontal state at all times, so that the height of the symmetrical point of the negative stiffness characteristic curve composed of the two second elastic members 52 is kept consistent with the equilibrium height of the first box 3.

[0036] Optionally, the second telescopic structure can be a device such as a hydraulic cylinder, a pneumatic cylinder, an electric cylinder, etc. that can perform telescopic movement; the second telescopic structure can also be a telescopic member, so that when the height of the first box 3 changes, the height of the second box 51 changes accordingly; the second telescopic structure can also include: a second driver 71 and a second telescopic member 72, the second driver 71 is connected to the support platform 1, and the two ends of the second telescopic member 72 are respectively connected to the second driver 71 and the second box 51. When the second driver 71 moves, it drives the second telescopic member 72 to extend and retract, and when the second telescopic member 72 extends and retracts, it drives the second box 51 to move in the vertical direction to adjust the height of the second box 51. In this embodiment, the second driver 71 is a linear motor.

[0037] like Figure 1 As shown, in an embodiment of the present invention, the dynamic vibration absorber with adjustable vibration absorption frequency further includes: a vibration acceleration sensor 81 and a controller 82. The vibration acceleration sensor 81 is arranged on the support platform 1, and the controller 82 is used to control the pump 63 to be turned off according to the vibration acceleration signal sent by the vibration acceleration sensor 81.

[0038] Specifically, when the rotating mechanism is running, the vibration acceleration sensor 81 collects the vibration acceleration signal of the support platform 1, and transmits the collected vibration acceleration signal to the controller 82. The controller 82 first performs Fourier transform on the vibration acceleration signal to obtain the excitation frequency. Then, the mass of the liquid in the first box 3 is calculated according to the excitation frequency. When the mass of the liquid in the first box 3 reaches the target value, the controller 82 controls the pump 63 to stop running so that the natural frequency of the dynamic vibration absorber is close to the excitation frequency.

[0039] Furthermore, if Figure 1 As shown, the dynamic vibration absorber with adjustable vibration absorption frequency further includes a liquid level sensor 83, which is arranged in the first box 3 and is used to detect the liquid level of the liquid in the first box 3. The controller 82 calculates the mass of the liquid in the first box 3 according to the excitation frequency, and then calculates the liquid level of each small box according to the volume of each small box in the first box 3. When the liquid level reaches the target height, the controller 82 controls the pump 63 to stop running.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dynamic vibration absorber with adjustable vibration absorption frequency and damping, characterized in that: include: A vibration isolator, a supporting platform, a first elastic member, a first box and a pair of stiffness adjustment mechanisms; The support platform is arranged on the vibration isolator, the first box is connected to the support platform through the first elastic member, and a pair of stiffness adjustment mechanisms are respectively arranged on both sides of the first box; Each of the stiffness adjustment mechanisms includes: a second box body and a second elastic member, the second box body is connected to the support platform, the second elastic member is arranged in the second box body, one end of the second elastic member passes through the second box body and is connected to the first box body, wherein the second elastic member is in a compressed state.

2. The dynamic vibration absorber with adjustable vibration absorption frequency according to claim 1, characterized in that: Each of the stiffness adjustment mechanisms further includes a first telescopic structure, which is disposed in the second box and connected to the second elastic member, and is used to adjust the pre-compression amount of the second elastic member.

3. The dynamic vibration absorber with adjustable vibration absorption frequency according to claim 2, characterized in that: Each of the stiffness adjustment mechanisms further includes a first baffle; The first baffle is disposed between the first telescopic structure and the second elastic member. The first baffle is connected to the first telescopic structure and can move under the action of the first telescopic structure. The second elastic member abuts against the first baffle.

4. The dynamic vibration absorber with adjustable vibration absorption frequency according to claim 2, characterized in that: Each of the stiffness adjustment mechanisms further includes a connecting rod, and two ends of the connecting rod are respectively connected to the first box body and the second elastic member.

5. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 1, characterized in that: A plurality of partitions are arranged in the first box body along the height direction and the width direction of the first box body to divide the space in the first box body into a plurality of cavities, each of which is filled with liquid.

6. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 4, characterized in that: It also includes a third box, in which liquid is arranged, the third box is connected to the first box through a pipeline, a pump is arranged on the pipeline, and the third box is used to adjust the weight of the first box; Wherein, each of the second boxes is telescopically connected to the supporting platform.

7. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 6, characterized in that: It also includes a pair of second telescopic structures, each of which has two ends connected to the support platform and the second box body, and the second telescopic structures are used to adjust the height of the second box body so that the connecting rod is always in a horizontal state after the height of the first box body changes.

8. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 6, characterized in that: It also includes a vibration acceleration sensor and a controller. The vibration acceleration sensor is arranged on the supporting platform. The controller is used for controlling the pump to be turned off according to the vibration acceleration signal sent by the vibration acceleration sensor.

9. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 8, characterized in that: It also includes a liquid level sensor, which is arranged in the first box body. The liquid level sensor is electrically connected to the controller, and the controller is used to control the pump to close according to the liquid level height detected by the liquid level sensor.

10. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 1, characterized in that: The second box is a metal damping structure.

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