Adjustable tree resonator for multi-frequency vibration and noise reduction

Abstract

The invention discloses an adjustable tree-shaped resonator for multi-frequency vibration and noise reduction, which comprises a trunk support, a plurality of adjusting inner cavities are arranged in the trunk support, an adjusting gear is arranged in the center of each adjusting inner cavity, each adjusting gear comprises an outer tooth, a fixed shaft hole and a key slot, and the trunk support is correspondingly provided with a key slot through hole. Branch cantilever structures of the same structure are arranged on the upper portion and the lower portion of the adjusting gear respectively, each branch cantilever structure comprises a cantilever beam and a rack, the racks are meshed with the adjusting gear, the two branch cantilever structures move in the opposite directions under rotation of the adjusting gear, first extending holes are formed in the corresponding extending positions of the trunk support, and the extending lengths are consistent. Adjusting rotating rods corresponding to the adjusting gears are arranged on the trunk support and inserted from the front face of the trunk support to drive the adjusting gears. The extension length of each group of branch cantilever structures is changed by rotating the adjusting knob and the adjusting gear, so that the first-order inherent frequency and vibration mode of each group of branch cantilever structures are adjusted.

Description

Technical Field

[0001] The present invention relates to the field of vibration engineering, and particularly to an adjustable tree-shaped resonator for multi-frequency vibration reduction and noise reduction. Background Art

[0002] Vibration and noise are common phenomena in the field of engineering. Vibration and noise in engineering equipment can affect the operational safety, reliability, and service life. Excessive vibration and noise can have an impact on physical and mental health and at the same time damage the comfort of the working and living environment, etc. With the progress of technology, higher requirements have been put forward for vibration and noise suppression. Currently, vibration and noise control can adopt passive control, semi-active control, and active control, etc. Among them, passive control is low in cost, easy to maintain, easy to ensure the original stability of the structure, and does not require external energy input, and has been widely used in civil engineering, machinery, aviation, aerospace and other fields.

[0003] As a typical passive control device, the dynamic vibration absorber has long attracted people's attention, such as the tuned mass damper, etc. Traditional vibration absorbers are sensitive to changes in the characteristics of the main structure and external excitation characteristics. Usually, it is necessary to tune its natural frequency to near the fundamental frequency of the main structure. If there is a large frequency deviation, the vibration reduction effect will decrease. With the increasing requirements of engineering structures, the complex environment, and the limited available space, it is necessary to enhance the environmental adaptability of the dynamic vibration absorber. However, traditional dynamic vibration absorbers have problems such as single frequency and difficult adjustment.

[0004] Multiple resonance peaks often appear in engineering structures, such as multi-layer structures, etc. In order to effectively suppress multi-frequency vibration and noise, it is necessary to introduce resonators with multiple natural frequencies. With the continuous improvement of control requirements, adjustability has become increasingly important. Currently, existing adjustable resonators are mostly active-adjusted single-degree-of-freedom systems or multi-degree-of-freedom systems. Such structures are complex in design, rely on external energy, and have a high control cost, resulting in an increase in production costs. In addition, the multi-degree-of-freedom system has modal coupling, and it is difficult to accurately control the corresponding frequencies of each degree of freedom, which is not conducive to achieving vibration reduction and noise reduction in multiple different frequency bands simultaneously. Summary of the Invention

[0005] Object of the Invention: In order to overcome the deficiencies of the background art, the present invention discloses an adjustable tree-shaped resonator for multi-frequency vibration reduction and noise reduction.

[0006] Technical solution: The adjustable tree-shaped resonator for multi-frequency vibration reduction and noise reduction disclosed by the present invention is installed on a controlled object and includes a trunk bracket. A plurality of adjustment cavities are provided at intervals up and down inside the trunk bracket. An adjustment gear is provided at the central position of each adjustment cavity. The adjustment gear includes external teeth, a fixed shaft hole, and a keyway communicating with the fixed shaft hole. Keyway through holes of the same size are opened at the positions of the trunk bracket corresponding to the fixed shaft hole and the keyway. Parallel branch cantilever structures are respectively provided on the upper and lower sides in the circumferential direction of the adjustment gear. The two branch cantilever structures in the same adjustment cavity are exactly the same. The branch cantilever structure includes a cantilever beam and a rack located on one side of the cantilever beam. The rack meshes with the adjustment gear. Under the rotation of the adjustment gear, the two branch cantilever structures move in opposite directions. The trunk bracket is provided with a first through hole at the position corresponding to the extension position of the branch cantilever structure. The lengths of the two branch cantilever structures extending in the same adjustment cavity are the same. Only the lengths of the cantilever beams of the branch cantilever structures in different adjustment cavities are different. An adjustment lever is provided on the trunk bracket corresponding to each adjustment gear. The adjustment lever is inserted from the front of the trunk bracket to drive the adjustment gear to rotate.

[0007] Further, the trunk bracket is of a cubic structure and includes two half-trunk brackets radially divided by the adjustment gear and bolted together.

[0008] Further, two adjustment cavities are vertically arranged at intervals.

[0009] Further, the trunk bracket is provided with a second through hole at the position corresponding to the retraction direction of each branch cantilever structure.

[0010] Further, a circular groove for placing the adjustment gear is opened at the axial position of the trunk bracket corresponding to the adjustment gear.

[0011] Further, the branch cantilever structure corresponding to the upper adjustment cavity is shorter than the branch cantilever structure corresponding to the lower adjustment cavity.

[0012] Further, the adjustment lever includes an adjustment knob, an adjustment rod, and an adjustment key. The adjustment rod and the adjustment key respectively correspond to the fixed shaft hole and the keyway. When the adjustment knob is located outside the trunk bracket, and the adjustment rod and the adjustment key are inserted into the fixed shaft hole, the keyway, and the keyway through hole, it is in the locked state. When the adjustment rod is pulled outwards so that the adjustment key disengages from the keyway through hole, it is in the adjustment state. Rotating the adjustment knob can realize the telescopic control of the branch cantilever structure.

[0013] Further, the cantilever beam is a rectangular structural beam.

[0014] Further, different extension lengths of the branch cantilever structure correspond to different suppression frequencies, and corresponding frequency scales are provided on both the cantilever beam and the adjustment knob.

[0015] Beneficial effects: Compared with the prior art, by rotating the adjustment knob and the adjustment gear, the present invention makes the rack on the branch cantilever structure move, changes the extension length of each group of branch cantilever structures, and realizes the adjustment of the first-order natural frequency and vibration mode of each group of branch cantilever structures.

[0016] The present invention can achieve precise frequency adjustment without external energy input, and the first-order vibration modes of different groups of branch cantilever structures are decoupled from each other, which is easy to accurately adjust the frequencies under different working conditions, avoiding energy consumption and secondary design costs. By adjusting each natural frequency of this resonator to the target frequency range, vibration and noise suppression in multiple different target frequency bands can be achieved. Brief description of the drawings

[0017] Figure 1 is a schematic diagram of the external structure of the present invention;

[0018] Figure 2 is a schematic diagram of the internal structure of the present invention;

[0019] Figure 3 is a schematic diagram of the semi-body structure of the trunk bracket of the present invention;

[0020] Figure 4 is a structural diagram of the adjustment gear of the present invention;

[0021] Figure 5 is a structural diagram of the adjustment rod of the present invention;

[0022] Figure 6 is a structural diagram of the branch cantilever structure of the present invention;

[0023] Figure 7 is a curve graph of the sound insulation amount before and after adding the tree-shaped resonator of the present invention. Detailed implementation manners

[0024] The technical solutions of the present invention will be further described below in conjunction with the drawings and embodiments.

[0025] As Figures 1-6 shown, the adjustable tree-shaped resonator for multi-frequency vibration reduction and noise reduction is installed on the controlled object, and includes a trunk bracket 1. A plurality of adjustment cavities 2 are arranged at intervals up and down inside the trunk bracket 1.

[0026] In this embodiment, two adjustment cavities 2 are arranged vertically.

[0027] A regulating gear 3 is provided at the central position of each regulating inner cavity 2. The regulating gear 3 includes external teeth 301, a fixed shaft hole 302, and a keyway 303 communicating with the fixed shaft hole 302. The tree trunk bracket 1 is provided with keyway through holes 4 of the same size at positions corresponding to the fixed shaft hole 302 and the keyway 303. On the upper and lower sides in the circumferential direction of the regulating gear 3, there are respectively provided branch cantilever structures 5 that are parallel to each other. The two branch cantilever structures 5 in the same regulating inner cavity 2 are exactly the same. The branch cantilever structure 5 includes a cantilever beam 501 and a rack 502 located on one side of the cantilever beam 501. The cantilever beam 501 is a rectangular structural beam. The rack 502 meshes with the regulating gear 3. Under the rotation of the regulating gear 3, the two branch cantilever structures 5 move in opposite directions. The tree trunk bracket 1 is provided with a first protruding hole 6 at the protruding position corresponding to the branch cantilever structure 5. The size of the first protruding hole 6 is slightly larger than that of the cantilever beam 501 to ensure the tight combination of the tree trunk bracket and the branch cantilever and improve the regulating accuracy.

[0028] The lengths of the two branch cantilever structures 5 protruding in the same regulating inner cavity 2 are the same. Only the length of the cantilever beam 501 of the branch cantilever structures 5 in different regulating inner cavities 2 is different. A regulating screw rod 7 is provided on the tree trunk bracket 1 corresponding to each regulating gear 3. The regulating screw rod 7 is inserted from the front of the tree trunk bracket 1 to drive the regulating gear 3 to rotate.

[0029] The tree trunk bracket 1 is of a cube structure and includes two tree trunk bracket halves 101 radially divided by the regulating gear 3 and bolted together.

[0030] The tree trunk bracket 1 is provided with a second protruding hole 8 at the retracting direction corresponding to each branch cantilever structure 5 to provide appropriate protection for the tree trunk bracket 1 when the branch cantilever structure 5 retracts excessively.

[0031] The tree trunk bracket 1 is provided with a circular groove 9 for placing the regulating gear 3 at the axial position corresponding to the regulating gear 3.

[0032] The branch cantilever structure 5 corresponding to the regulating inner cavity 2 located above is shorter than the branch cantilever structure 5 corresponding to the regulating inner cavity 2 located below.

[0033] The regulating screw rod 7 includes a regulating knob 701, a regulating rod 702, and a regulating key 703. The regulating rod 702 and the regulating key 703 respectively correspond to the fixed shaft hole 302 and the keyway 303. The regulating knob 701 is located outside the tree trunk bracket 1. When the regulating rod 702 and the regulating key 703 are inserted into the fixed shaft hole 302, the keyway 303, and the keyway through hole 4, they are in the locked state. When the regulating rod 702 is pulled outwards so that the regulating key 703 disengages from the keyway through hole 4, it is in the regulating state. Rotating the regulating knob 701 can realize the telescopic control of the branch cantilever structure 5.

[0034] The different extended lengths of the branch cantilever structure 5 correspond to different suppression frequencies, and corresponding frequency scales are set on both the cantilever beam 501 and the adjustment knob 701.

[0035] By rotating the adjustment knob 701, the adjustment gear 3 is controlled to rotate. The external teeth 301 on the adjustment gear 3 drive the rack 502 on the branch cantilever structure 5 to move horizontally through meshing, controlling the telescopic length of the cantilever beam 501 outside the tree trunk bracket 1, and adjusting the frequency corresponding to the first-order vibration mode of the cantilever beam 501. The calculation formula for the frequency corresponding to the above first-order vibration mode is as follows:

[0036]

[0037] Among them, the length of the cantilever beam 501 extending outside the tree trunk bracket 1 is l r , the Young's modulus is E, the cross-sectional area is A, the density is ρ, and the moment of inertia of the cross-section is I r .

[0038] According to the above calculation method, frequency scales corresponding to the length are marked on the branch cantilever structure 5 and the adjustment knob 701. During use, first rotate the adjustment knob 701 so that the scale on it is consistent with the cantilever beam 501 to complete the zero adjustment work; according to the dynamic characteristics of the structure, the frequency of the cantilever structure is corresponding to the natural frequency of the controlled structure.

[0039] The controlled structure selected in this embodiment is a grid structure commonly used in engineering. This structure is fixed around, and the material is nylon. The length and width of the grid structure are both 100 mm, the height is 34 mm, the wall thickness of the upper and lower plates is 2 mm, and the wall thickness of the side is 4 mm. In this embodiment, the tree-shaped resonator is fixed inside the original grid structure, and the scales on the branch cantilevers are set to 580 Hz and 1940 Hz respectively by the adjustment knob. The widths of the two groups of branch cantilevers are 4.5 mm, the thicknesses are 0.5 mm, the lengths are 25.5 mm and 14.5 mm respectively, and the total mass of the tree trunk bracket is 12 g. In this embodiment, the sound insulation amount is used as an index to measure its sound insulation performance. The higher the sound insulation amount, the better its sound insulation performance, and vice versa. Figure 7 are the sound insulation amount curves of the original grid structure and the grid structure with the tree-shaped resonator of the present invention added. For the grid structure without a resonator, there are two valleys in the sound insulation amount at 580 Hz and 1940 Hz. Obviously, the sound insulation performance corresponding to these two frequencies is poor, and the sound wave transmission is relatively serious. For the grid structure with the tree-shaped resonator of the present invention added, the sound insulation amount increases at these two frequencies of 580 Hz and 1940 Hz, and the sound insulation performance is significantly improved. This shows that the tree-shaped resonator of the present invention can achieve the vibration reduction and noise reduction effects at different frequencies.

Claims

1. An adjustable tree-type resonator for multi-frequency vibration and noise reduction, mounted on a controlled object, characterized in that: The invention comprises a trunk support 1, wherein a plurality of adjusting inner chambers 2 are arranged at intervals from top to bottom in the trunk support 1, an adjusting gear 3 is arranged at the center of each adjusting inner chamber 2, the adjusting gear 3 comprises an outer tooth 301, a fixed shaft hole 302 and a keyway 303 connected to the fixed shaft hole 302, the trunk support 1 is provided with keyway through holes 4 of equal sizes at positions corresponding to the fixed shaft hole 302 and the keyway 303, the adjusting gear 3 is provided with branch cantilever structures 5 parallel to each other on the upper and lower sides, the two branch cantilever structures 5 in the same adjusting inner chamber 2 are exactly the same, the branch cantilever structure 5 comprises a cantilever beam 501 and a cantilever beam 501 located at The rack 502 on one side of the cantilever beam 501 is meshed with the adjusting gear 3. When the adjusting gear 3 rotates, the two branch cantilever structures 5 move in opposite directions. The trunk support 1 is provided with a first extension hole 6 corresponding to the extension position of the branch cantilever structure 5. The two branch cantilever structures 5 in the same adjustment cavity 2 have the same extension length. The branch cantilever structures 5 in different adjustment cavities 2 only have the length of the cantilever beam 501 different. An adjustment rotary rod 7 is provided on the trunk support 1 corresponding to each adjustment gear 3. The adjustment rotary rod 7 is inserted from the front of the trunk support 1 to drive the adjustment gear 3 to rotate.

2. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 1, characterized in that: The trunk support 1 is a cubic structure, including two trunk support halves 101 radially divided by an adjusting gear 3 and bolted together.

3. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 1, characterized in that: The two regulating inner cavities 2 are arranged vertically at intervals.

4. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 1, characterized in that: The tree trunk support 1 is provided with a second extension hole 8 corresponding to the retraction direction of each branch cantilever structure 5 .

5. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 1, characterized in that: The trunk support 1 is provided with a circular groove 9 corresponding to the axial position of the adjusting gear 3 for placing the adjusting gear 3 .

6. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 1, characterized in that: The branch cantilever structure 5 corresponding to the upper regulating inner cavity 2 is shorter than the branch cantilever structure 5 corresponding to the lower regulating inner cavity 2.

7. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 1, characterized in that: The adjusting rotary rod 7 includes an adjusting knob 701, an adjusting rod 702 and an adjusting key 703. The adjusting rod 702 and the adjusting key 703 correspond to the fixed shaft hole 302 and the key slot 303 respectively. The adjusting knob 701 is located on the outside of the trunk support 1. The adjusting rod 702 and the adjusting key 703 are inserted into the fixed shaft hole 302, the key slot 303 and the key slot through hole 4 and are in a locked state. When the adjusting rod 702 is pulled outward to cause the adjusting key 703 to disengage from the key slot through hole 4, it is in an adjusting state. Rotating the adjusting knob 701 can realize the telescopic control of the branch cantilever structure 5.

8. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 1, characterized in that: The cantilever beam 501 is a rectangular structural beam.

9. The adjustable tree-type resonator for multi-frequency vibration and noise reduction according to claim 7, characterized in that: Different extension lengths of the tree branch cantilever structure 5 correspond to different suppression frequencies, and corresponding frequency scales are set on the cantilever beam 501 and the adjustment knob 701.

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