A passive dynamic vibration absorber and its assembly method

Abstract

The present invention relates to a passive dynamic vibration absorber and an assembly method thereof. The vibration absorber includes an upper sleeve, an adjusting piece, an upper pressing block, an upper spring piece, a middle pressing block, a lower spring piece, a lower pressing block, a lower sleeve, and a mandrel. The central positions of the lower spring piece and the upper spring piece are through holes, and are fixed on the mandrel through the lower sleeve, the upper sleeve, and sleeve fasteners. The upper end of the upper spring piece is connected to the adjusting piece through the upper pressing block. A middle pressing block is connected between the upper spring piece and the lower spring piece. The lower end of the lower spring piece is connected to the lower pressing block. The outer circles of the lower spring piece and the upper spring piece are provided with uniformly distributed through holes, and the positions are consistent with the outer through holes of the lower pressing block, the middle pressing block, the adjusting piece, and the outer threaded holes of the upper pressing block, and are pressed together through outer fasteners. The present invention has the characteristics of good lateral stability, fine frequency tuning, and a limiting function, and can effectively suppress the line spectrum vibration of equipment.

Description

Technical Field

[0001] The present invention relates to a passive dynamic vibration absorber, belonging to the technical field of vibration and noise control. Background Art

[0002] To reduce the vibration transmitted from a power device to the outside world, vibration isolators are usually used for vibration isolation. However, the characteristic line spectrum of the vibration still exists and is relatively prominent after passing through the vibration isolator. For a single-frequency line spectrum, using a dynamic vibration absorber can often bring very obvious effects. By installing a dynamic vibration absorber with the same natural frequency as the single-frequency line spectrum frequency, the oscillator of the vibration absorber resonates, thereby taking away the vibration energy of the main vibration system and achieving the purpose of reducing the vibration energy of the characteristic line spectrum of the equipment transmitted from the main vibration system to the outside world.

[0003] The invention patent with the patent number CN201710751468.8 and the name of "a spring-type vibration absorber" discloses a spring-type vibration absorber, which is composed of a mass element, a stiffness element, a guide rod, a positioning sleeve and a locknut. The vibration absorber with this structure uses a helical spring as the stiffness element. On the one hand, the lateral stiffness is poor. On the other hand, the damping is large: one is that the helical spring itself has a large structural damping, and the other is that it is easy to have contact between the mass element and the guide rod, thus bringing frictional damping. For equipment with a relatively low single-frequency vibration level itself, the excessive damping makes the installed vibration absorber not easy to resonate, resulting in a greatly reduced vibration absorption function.

[0004] The utility model with the patent number CN201620650885.4 and the name of "frequency-adjustable diaphragm-type vibration absorber" discloses a frequency-adjustable diaphragm-type vibration absorber, which mainly consists of a support rod, an outer washer, a diaphragm, an inner washer, a mass block, a frequency adjustment element, a screw, a flat washer, etc. The vibration absorber uses a diaphragm as the elastic element. The diaphragm is provided with a hollow structure formed by more than one concentric arc groove distributed periodically around the center of the circle. It is relatively difficult to control the law of the stiffness characteristics of this structure during design. In addition, the vibration absorber has no limiting structure. In case of large-scale impacts, human trampling, heavy object dropping, etc., the diaphragm may undergo permanent yielding or even fracture, affecting the service life of the vibration absorber. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned technical problems and defects existing in the prior art, and provide a passive dynamic vibration absorber and its assembly method.

[0006] To achieve the above object, the technical solution adopted by the present invention to achieve the object is: a passive dynamic vibration absorber includes an upper sleeve, an adjusting piece, an upper pressing block, an upper spring piece, a middle pressing block, a lower spring piece, a lower pressing block, a lower sleeve, and a core shaft. The central positions of the lower spring piece and the upper spring piece are through holes, and are fixed on the core shaft through the lower sleeve, the upper sleeve, and the sleeve fasteners. The upper end of the upper spring piece is connected to the adjusting piece through the upper pressing block. A middle pressing block is connected between the upper spring piece and the lower spring piece. The lower end of the lower spring piece is connected to a lower pressing block. The outer circles of the lower spring piece and the upper spring piece are provided with uniformly distributed through holes, and are in the same positions as the peripheral through holes of the lower pressing block, the middle pressing block, the adjusting piece, and the peripheral threaded holes of the upper pressing block, and are pressed tightly together through peripheral fasteners.

[0007] Further, the upper sleeve and the lower sleeve are provided with a limiting structure, and the limiting structure is a convex platform extending outwards. The outer diameter of the convex platform is greater than the minimum inner diameter of the central through holes of the adjusting piece, the upper pressing block, the middle pressing block, and the lower pressing block.

[0008] Further, the upper spring piece and the lower spring piece are provided with a hollow structure evenly distributed at equal angles around the center of the circle. The remaining part is a "cantilever", and both ends of the cantilever are rounded structures.

[0009] Further, the number of the cantilevers ≥ 2.

[0010] Further, the adjusting piece is an adjusting piece with various thicknesses available.

[0011] Further, the positions around the threaded hole on the lower side of the upper pressing block, around the through holes on the upper and lower sides of the middle pressing block, and around the through hole on the upper side of the lower pressing block are convex platform structures.

[0012] An assembly method of a passive dynamic vibration absorber includes the following steps:

[0013] The first step: Place the lower pressing block, the lower spring piece, the middle pressing block, the lower sleeve, the upper spring piece, the upper sleeve, and the upper pressing block in sequence and align the positions of the outer circle through holes and the outer circle threaded holes;

[0014] The second step: Pass the core shaft through the inner circle through hole and install the sleeve fasteners without tightening;

[0015] The third step: Pass the bolts of the peripheral fasteners through the outer circle through holes and threaded holes, tighten them, and then tighten the sleeve fasteners;

[0016] The fourth step: Install the adjusting piece, the washers and nuts of the peripheral fasteners, and tighten them;

[0017] The fifth step: If frequency modulation is required, use the adjusting pieces in combination.

[0018] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0019] 1. Compared with the traditional cantilever - type passive dynamic vibration absorber, the present invention can reduce the size of the vibration absorber extending outwards, make full use of the vertical space to achieve the vibration absorption function;

[0020] 2. Compared with the traditional helical - spring - type passive dynamic vibration absorber, the present invention has a larger lateral stiffness and a smaller damping, and has a better vibration absorption effect even for a smaller line - spectrum vibration level;

[0021] 3. Compared with the utility model with the patent number CN201620650885.4 and named "frequency - adjustable diaphragm - type vibration absorber", the present invention includes a limiting structure, which can not only prevent the large deformation and yield of the reed caused by impacts, trampling, heavy object falling, etc., but also prevent the phenomenon of injury to people and objects caused by the falling of the oscillator in case the reed breaks. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of an embodiment of the present invention;

[0023] Figure 2 is a schematic diagram of the reed in the embodiment of the present invention;

[0024] In the figure: 1 is an outer fastener, 2 is a sleeve fastener, 3 is an upper sleeve, 4 is an adjusting piece, 5 is an upper pressing block, 6 is an upper reed, 7 is a middle pressing block, 8 is a lower reed, 9 is a lower pressing block, 10 is a lower sleeve, 11 is a mandrel. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, and in combination with the drawings and embodiments, the present invention will be further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] As Figure 1 and Figure 2 shown, a passive dynamic vibration absorber includes an outer fastener 1, a sleeve fastener 2, an upper sleeve 3, an adjusting piece 4, an upper pressing block 5, an upper reed 6, a middle pressing block 7, a lower reed 8, a lower pressing block 9, a lower sleeve 10, and a mandrel 11. The central positions of the lower reed 8 and the upper reed 6 are through - holes, and are fixed on the mandrel 11 through the lower sleeve 10, the upper sleeve 3, and the sleeve fastener 2. The upper end of the upper reed 6 is connected to the adjusting piece 4 through the upper pressing block 5. A middle pressing block 7 is connected between the upper reed 6 and the lower reed 8. The lower end of the lower reed 8 is connected to the lower pressing block 9. The outer circles of the lower reed 8 and the upper reed 6 are provided with uniformly distributed through - holes, and are in the same position as the outer through - holes of the lower pressing block 9, the middle pressing block 7, the adjusting piece 4, and the outer threaded holes of the upper pressing block 5, and are pressed together through the outer fastener 1.

[0027] The upper sleeve 3 and the lower sleeve 10 are provided with a limiting structure, which is a convex platform extending outwards. The outer diameter of the convex platform is larger than the minimum inner diameter of the central through holes of the adjusting piece 4, the upper pressing block 5, the middle pressing block 7, and the lower pressing block 9, which can prevent the yield phenomenon of the reed caused by large deformation. In addition, it can also prevent the quality components from falling in case the reed breaks, protecting the safety of the equipment and personnel;

[0028] The upper reed 6 and the lower reed 8 contain a hollow structure evenly distributed at equal angles around a circle. The remaining part is called a "cantilever". The two ends of the cantilever are rounded structures to prevent stress concentration. The number of cantilevers is not less than 2, and it is more convenient to achieve the desired stiffness range according to the design requirements.

[0029] The adjusting piece 4 is not limited to one thickness, and multi-level adjustment of the frequency is achieved by combined use.

[0030] Threaded holes are evenly distributed on the outer circle of the upper pressing block 5. When replacing the adjusting piece, the assembled parts can be prevented from being disassembled.

[0031] The positions around the threaded holes on the lower side of the upper pressing block 5, around the through holes on the upper and lower sides of the middle pressing block 7, and around the through holes on the upper side of the lower pressing block 9 are convex platform structures, which can greatly weaken the nonlinearity of the reed and approximate to linearity within the dynamic range of the reed.

[0032] The working principle of the present invention:

[0033] The passive dynamic vibration absorber can be directly installed on the main structure or through a transition structure. The natural frequency of the vibration absorber is consistent with the target frequency to be controlled by the main structure. When the main structure vibrates, the oscillator of the vibration absorber will vibrate with the main structure, and the energy of the main structure is absorbed to achieve the purpose of reducing the line spectrum vibration level. The reed is a metal structure, and its damping ratio usually does not exceed 5‰, and the amplification factor is not less than 200 times, which means that even a small vibration level of the main structure can obtain a large vibration acceleration of the oscillator. By combining and installing the adjusting piece, fine frequency adjustment of the passive dynamic vibration absorber can be achieved.

[0034] The assembly method of the passive dynamic vibration absorber of the present invention includes the following steps:

[0035] The first step: Place the lower pressing block, the lower reed, the middle pressing block, the lower sleeve, the upper reed, the upper sleeve, and the upper pressing block in sequence and align the positions of the outer circle through holes and the outer circle threaded holes;

[0036] The second step: Pass the mandrel through the inner circle through hole and install the sleeve fastener without tightening;

[0037] The third step: Pass the bolts of the peripheral fastener through the outer circle through hole and the threaded hole, tighten them, and then tighten the sleeve fastener;

[0038] The fourth step: Install the adjusting piece, the washer and the nut of the peripheral fastener, and tighten them;

[0039] Step 5: If there is a need for frequency modulation, use the trim tab in combination.

[0040] As mentioned above, it is only the preferred specific embodiment of the present invention. Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, any person skilled in the art can make various corresponding changes and deformations according to the present invention. All technical solutions formed by equivalent replacement or equivalent transformation should fall within the protection scope of the claims appended to the present invention.

Claims

1. A passive dynamic vibration absorber, comprising an upper sleeve (3), an adjusting piece (4), an upper pressing block (5), an upper reed (6), a middle pressing block (7), a lower reed (8), a lower pressing block (9), a lower sleeve (10), and a mandrel (11), characterized in that: The central positions of the lower spring plate (8) and the upper spring plate (6) are through holes, which are fixed on the mandrel (11) by the lower sleeve (10), the upper sleeve (3), and the sleeve fastener (2). The upper end of the upper spring plate (6) is connected to the adjusting piece (4) through the upper pressing block (5). A middle pressing block (7) is connected between the upper spring plate (6) and the lower spring plate (8). The lower end of the lower spring plate (8) is connected to a lower pressing block (9). The outer circles of the lower spring plate (8) and the upper spring plate (6) are provided with uniformly distributed through holes, and the positions are consistent with the peripheral through holes of the lower pressing block (9), the middle pressing block (7), the adjusting piece (4), and the peripheral threaded holes of the upper pressing block (5), and they are pressed tightly together by the peripheral fastener (1). The upper sleeve (3) and the lower sleeve (10) are provided with a limiting structure, and the limiting structure is a convex platform extending outwards. The outer diameter of the convex platform is larger than the minimum inner diameter of the central through holes of the adjusting piece (4), the upper pressing block (5), the middle pressing block (7), and the lower pressing block (9). The positions around the threaded holes on the lower side of the upper pressing block (5), the positions around the through holes on the upper and lower sides of the middle pressing block (7), and the positions around the through holes on the upper side of the lower pressing block (9) are convex platform structures.

2. The passive dynamic vibration absorber according to claim 1, characterized in that: The upper spring plate (6) and the lower spring plate (8) are provided with a hollow structure evenly distributed at equal angles around the center of the circle, and the remaining part is a "cantilever", and both ends of the cantilever are rounded structures.

3. The passive dynamic vibration absorber according to claim 2, characterized in that: The number of the cantilevers ≥ 2.

4. The passive dynamic vibration absorber according to claim 1, characterized in that: The adjusting piece (4) is an adjusting piece with various thicknesses available.

5. An assembly method of the dynamic vibration absorber according to any one of claims 1 to 4, characterized in that, It includes the following steps: The first step: Place the lower pressing block (9), the lower spring plate (8), the middle pressing block (7), the lower sleeve (10), the upper spring plate (6), the upper sleeve (3), and the upper pressing block (5) in sequence and align the positions of the outer circle through holes and the outer circle threaded holes. The second step: Pass the mandrel (11) through the inner circle through hole and install the sleeve fastener (2), without tightening it. The third step: Pass the bolts of the peripheral fastener (1) through the outer circle through holes and the threaded holes, and tighten them, and then tighten the sleeve fastener (2). The fourth step: Install the adjusting piece (4), the washer and nut of the peripheral fastener (1), and tighten them. The fifth step: If frequency modulation is required, use the adjusting piece (4) in combination.

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