Dynamic vibration absorber with adjustable vibration frequency and damping

Abstract

The present invention relates to the technical field of vibration reduction equipment, and provides a dynamic vibration absorber with damping and adjustable vibration absorption frequency, comprising: a vibration isolator, a support 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 stiffness adjustment mechanism comprises: a second box and a second elastic member, the second box is connected to the support 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. The above-mentioned dynamic vibration absorber with damping and adjustable vibration absorption frequency utilizes a combination of positive stiffness and negative stiffness to make the dynamic vibration absorber with damping and adjustable vibration absorption frequency have a high static stiffness value and a low dynamic stiffness value, thereby being able to effectively isolate low-frequency vibrations.

Description

Technical Field

[0001] The present 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] Rotating machinery on ships is typically mounted on supporting platforms. During operation, vibrations generated by the rotating machinery are transmitted outward through the supporting platforms, potentially causing joints to loosen. In severe cases, this vibration transmission can lead to immeasurable economic losses. To address this issue, current technology involves installing dynamic vibration absorbers on the supporting platforms to achieve effective vibration reduction.

[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 the overall deformation of the dynamic vibration absorber to be larger, and then a larger deformation space needs to be reserved, resulting in reduced space utilization. Based on this, setting up 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 present 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 a 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 support 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 comprises: a second box and a second elastic member, the second box is connected to the support 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 the dynamic vibration absorber with adjustable vibration absorption frequency provided by the present invention, each of the stiffness adjustment mechanisms further includes a connecting rod, and both ends of the connecting rod are respectively connected to the first box 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 along the height and width directions of the first box to divide the space in the first box into a plurality of cavities, each of which is filled with liquid.

[0010] According to the present invention, a dynamic vibration absorber with damping and adjustable vibration absorption frequency also includes a third box body, in which liquid is provided. The third box body is connected to the first box body through a pipeline, and a pump is provided on the pipeline. 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 support platform.

[0011] According to the present invention, a dynamic vibration absorber with adjustable vibration absorption frequency and damping also includes a pair of second telescopic structures, and the two ends of each second telescopic structure are respectively connected to the support platform and the second box body. The second telescopic structure is 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] According to the present invention, a dynamic vibration absorber with adjustable vibration absorption frequency and damping 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 closed according to the vibration acceleration signal sent by the vibration acceleration sensor.

[0013] According to the present invention, a dynamic vibration absorber with adjustable vibration absorption frequency and damping 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 the dynamic vibration absorber with adjustable vibration absorption frequency provided by the present invention, the second box is a metal damping structure.

[0015] The dynamic vibration absorber with damping and adjustable vibration absorption frequency provided by the present invention is provided with a first elastic member and a second elastic member, and the second elastic member is placed in a compressed state. By utilizing a combination of positive stiffness and negative stiffness, 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, a brief introduction is given below to 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 any 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:

[0020] 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

[0021] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0022] The following combination Figure 1 and Figure 2 The invention describes a dynamic vibration absorber with damping and adjustable vibration absorption frequency.

[0023] 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 includes: 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 includes: 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.

[0024] Specifically, in this embodiment, the first housing 3 is connected to the support platform 1 via the first elastic member 2. The first housing 3 is suspended in the air, and the first elastic member 2 provides positive stiffness. The two second elastic members 52 on the left and right sides of the first housing 3 are both compressed, providing negative stiffness in the vertical direction. The combination of the positive and negative stiffness of the three elastic members provides quasi-zero stiffness at the static equilibrium position of the first housing 3. That is, near the static equilibrium position of the first housing 3, a larger static stiffness value and a smaller dynamic stiffness value are present. The larger static stiffness value ensures that the first housing 3 has smaller deformation under the weight of the liquid, while the smaller dynamic stiffness value reduces the vibration absorption frequency of the dynamic vibration absorber and improves low-frequency vibration absorption performance.

[0025] In this embodiment of the present invention, first housing 3 is elastically connected to support platform 1, serving as the main structure of the dynamic vibration absorber. The natural frequency of this main structure is designed to be close to the excitation frequency of the primary vibration system, thereby transferring vibration energy through resonance and achieving vibration reduction. This eliminates the need for additional equipment, resulting in a simple and compact dynamic vibration absorber that does not require additional space.

[0026] The embodiment of the present invention provides a dynamic vibration absorber with damping and adjustable vibration absorption frequency. By arranging a first elastic member and a second elastic member, and placing the second elastic member in a compressed state, the dynamic vibration absorber with damping and adjustable vibration absorption frequency utilizes a combination of positive stiffness and negative stiffness to have a high static stiffness value and a low dynamic stiffness value, thereby being able to effectively isolate low-frequency vibrations.

[0027] In the embodiment of the present invention, the second box 51 is a metal damping structure, which can suppress the vibration of the first box 3 from being transmitted to the supporting platform 1 .

[0028] like Figure 2 As shown, in an embodiment of the present invention, each stiffness adjustment mechanism 5 further includes a first telescopic structure, which is disposed within the second housing 51 and connected to the second elastic member 52. The first telescopic structure is used to drive the second elastic member 52 to compress, thereby adjusting 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 vibrations 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, or 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, wherein the two ends of the first telescopic member 57 are respectively connected to the inner wall of the second housing 51 and the first driver 53, and the first driver 53 is connected to the second elastic member 52. When the first driver 53 moves, it drives the first telescopic member 57 to extend, thereby adjusting the pre-compression amount of the second elastic member 52. Optionally, the first driver 53 can be a linear motor.

[0029] Optionally, the first elastic member 2 and the second elastic member 52 may be springs.

[0030] 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. The first baffle 54 is connected to the first driver 53. When the first driver 53 moves, it can push the first baffle 54 toward the first box 3, thereby adjusting the pre-compression amount of the second elastic member 52.

[0031] In an optional embodiment of the present invention, the second box body 51 can be a structure with an open top, an open front side, or an open rear side to accommodate 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 body 51 and is connected to the first box body 3; in another optional embodiment, the end of the second box body 51 adjacent to the first box body 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 can be placed in the second box body 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 body 3.

[0032] like Figure 2 As shown, each stiffness adjustment mechanism 5 further includes a connecting rod 56 , and both ends of the connecting rod 56 are connected to the first box body 3 and the second elastic member 52 respectively.

[0033] 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 in each small box is more likely to slosh and collide with the wall of the small box to generate liquid damping. Compared with the traditional dynamic vibration absorber that only has mass and stiffness effects, the dynamic vibration absorber with adjustable vibration frequency provided by the embodiment of the present invention uses the sloshing effect of several shallow liquid boxes to provide a damping factor, and uses the characteristic that damping can significantly reduce the vibration peak at the resonant frequency to achieve vibration reduction of the support platform 1.

[0034] like Figure 1 As shown, in an embodiment of the present invention, the dynamic vibration absorber with adjustable vibration absorption frequency and damping further includes a third box 61. The third box 61 contains liquid and is connected to the first box 3 via a pipe 62. The pipe 62 is provided with a pump 63, which 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.

[0035] Specifically, in the prior art, conventional dynamic vibration absorbers have fixed mass and stiffness, performing well under specific operating conditions and a single frequency, but failing to meet vibration reduction requirements under diverse operating conditions. In this embodiment, when the operating conditions of the rotating mechanism change, pump 63 is activated to pump the liquid within third tank 61 into first tank 3, causing the weight of first tank 3 to change, thereby altering the natural frequency of the dynamic vibration absorber and thereby reducing vibrations of varying frequencies. In this embodiment, the stiffness of first tank 3 is provided by first elastic member 2 and two second elastic members 52, while the mass of first tank 3 is comprised of the weight of the housing and the mass of the liquid within (the weight of partition 31 is negligible). This decoupling of stiffness and mass ensures that the resonant frequency of the dynamic vibration absorber varies monotonically with the mass of the liquid, exhibiting no extremes other than the endpoints within a certain parameter range. This enables dynamic vibration absorption across a wide frequency band.

[0036] 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, the two ends of the second telescopic structure are respectively connected to the support 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 making the connecting rod 56 always in a horizontal state, so that the height of the symmetrical point of the negative stiffness characteristic curve composed of the two second elastic members 52 is consistent with the equilibrium height of the first box 3.

[0037] Optionally, the second telescopic structure can be a device capable of telescopic movement, such as a hydraulic cylinder, a pneumatic cylinder, or an electric cylinder; 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.

[0038] like Figure 1 As shown, in an embodiment of the present invention, the dynamic vibration absorber with adjustable vibration absorption frequency and damping further includes: a vibration acceleration sensor 81 and a controller 82. The vibration acceleration sensor 81 is disposed on the support platform 1, and the controller 82 is used to control the pump 63 to shut down according to the vibration acceleration signal sent by the vibration acceleration sensor 81.

[0039] Specifically, when the rotating mechanism is operating, 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 a Fourier transform on the vibration acceleration signal to obtain the excitation frequency. Then, the mass of the liquid in the first tank 3 is calculated based on the excitation frequency. When the mass of the liquid in the first tank 3 reaches the target value, the controller 82 controls the pump 63 to stop operation, so that the natural frequency of the dynamic vibration absorber is close to the excitation frequency.

[0040] Further, if Figure 1 As shown, the dynamic vibration absorber with adjustable vibration absorption frequency and damping also includes a liquid level sensor 83, which is disposed within the first tank 3 and is used to detect the liquid level within the first tank 3. A controller 82 calculates the mass of the liquid within the first tank 3 based on the excitation frequency and then calculates the liquid level within each small tank based on the volume of each small tank within the first tank 3. When the liquid level reaches the target height, the controller 82 controls the pump 63 to stop operation.

[0041] 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 various 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, a pair of stiffness adjustment mechanisms and a third box; The support platform is provided on the vibration isolator, the first box is connected to the support platform via the first elastic member, and a pair of stiffness adjustment mechanisms are respectively provided on both sides of the first box; Each of the stiffness adjustment mechanisms includes: a second box, a second elastic member, a first telescopic structure and a connecting rod, wherein the second box is connected to the support platform, the second elastic member is disposed 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, the first telescopic structure is disposed in the second box and is connected to the second elastic member, the first telescopic structure is used to adjust the pre-compression amount of the second elastic member, and the two ends of the connecting rod are respectively connected to the first box and the second elastic member; Liquid is contained in the third box, the third box is connected to the first box via a pipeline, a pump is provided 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 support platform.

2. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 1, 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 is movable under the action of the first telescopic structure. The second elastic member abuts against the first baffle.

3. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 1, characterized in that: 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 which is filled with liquid.

4. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 1, 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 after the height of the first box body changes, the connecting rod is always in a horizontal state.

5. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 1, 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 to control the pump to be turned off according to the vibration acceleration signal sent by the vibration acceleration sensor.

6. The dynamic vibration absorber with adjustable vibration absorption frequency and damping according to claim 5, characterized in that: It also includes a liquid level sensor, which is arranged in the first box body and is electrically connected to the controller. The controller is used to control the pump to be turned off according to the liquid level height detected by the liquid level sensor.

7. 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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