Boats and ships host computer damping base
Technical Field
The invention relates to a vibration reduction base for a marine main engine, and belongs to the technical field of vibration reduction of marine main engines.
Background
The excitation force of the ship main engine in the modern shipbuilding engineering is gradually increased, the weight of the ship structure is gradually reduced, and the capability of resisting the excitation force is reduced year by year, so that the problems of vibration and noise on the ship become more and more serious. With the improvement of science and technology and the improvement of life, the pursuit of people for comfortable environment is also increased year by year, and the demand for building ships with low noise and small vibration is more and more increased. The structural vibration caused by the excitation of the ship main engine can be divided into low-frequency vibration in the form of power and high-frequency vibration in the form of structural noise according to frequency. In diesel engines, structural noise is excited as long as there are gaps, which noise consists of the natural frequencies of the structural components that collide with one another and the high-frequency components in the gas pressure curve. The structural noise is transmitted to the hull base through the frame and the base and is transmitted to the whole ship, the hull system steel structure is welded, the damping is very small, so the structural noise can be transmitted far, and air noise and underwater noise are radiated from the bulkhead, the deck and the bottom of the ship, and the noise becomes one of main sources of ship noise and seriously influences the vitality of the ship. The ship main engine base with the vibration reduction function is the key for reducing the excitation force of the main engine, and the good main engine base can greatly reduce the generation of ship structure noise, increase the concealment of ships and further protect the safety of ship bodies and the health of crews.
At present, the structural forms of ship bases are various, but all have corresponding defects. Patent CN105840729A discloses a vibration damping base for a shafting bearing, which comprises a base main body sleeved outside a bearing, and a pair of truncated cone-shaped vibration damping covers sleeved outside the base main body, wherein the vibration damping covers are multilayer connecting pieces formed by a metal wire mesh block layer and an elastic metal diaphragm layer at intervals. The invention can be used in a ship propulsion shafting, is convenient to install and small in occupied space, has the double functions of damping the transverse and radial vibration of the shafting and sealing the water between cabins, but the damping method is too single and has less applicable working conditions. Patent CN201410289796.7 discloses a ship host machine base based on a muting technology and elastic shock absorption, which comprises two groups of upper-layer support bracket components, a plurality of elastic shock absorption support members and lower-layer support bracket components which are symmetrically arranged, wherein the elastic shock absorption support members are arranged between the two groups of upper-layer support bracket components and lower-layer support bracket components at intervals, the upper-layer support bracket components comprise strip-shaped panels, a plurality of upper-layer support brackets, support angle steel and upper vertical plates, the inner lower sides of the strip-shaped panels are vertically and fixedly connected with the upper sides of the support angle steel, and the upper-layer support brackets are arranged in the support angle steel at intervals and are vertically and fixedly connected with the support angle steel; the upper vertical plate is obliquely arranged between the outer lower side of the strip panel and the outer lower side of the supporting angle steel and is fixedly connected with the outer lower side of the strip panel, the two upper-layer supporting brackets in a group and the outer lower side of the supporting angle steel; the lower-layer support bracket assembly comprises two I-shaped sections, a plurality of lower-layer support brackets, a plurality of outer transverse rib plates and a plurality of outer vertical plates, the two I-shaped sections are arranged in parallel, the lower-layer support brackets between the two I-shaped sections are arranged at intervals and are respectively and vertically and fixedly connected with the inner sides of the two I-shaped sections; the outer transverse rib plates correspond to the lower support toggle plates one by one and are respectively and vertically and fixedly connected with the outer side of the I-shaped section; the outer vertical plates are respectively and obliquely arranged on the outer sides of the corresponding I-shaped sections and fixedly connected with the corresponding I-shaped sections and the two outer transverse rib plates in a group, and through tests, the vibration can be reduced by 30%. However, the key elastic vibration-damping support is not described in detail in the invention, the sealing performance of the air vibration-damping air bag is difficult to guarantee, the phenomena of damage and air leakage are easy to occur in the vibration-damping process of a large host, the service life of the large host is greatly influenced, and the deformation of the air bag is gradually increased along with the extension of the service time, so that the centering performance of a main shaft system is influenced.
In the article of 'cantilever beam-based particle damping experiment', the particle damping vibration attenuation is applied to a cantilever beam structure by summerhans, and experiments prove the feasibility of the particle damping vibration attenuation, and the experiment result shows that the particle damping vibration attenuation can increase the damping ratio of the beam to 492 percent at most, so that the particle damping can effectively play a vibration attenuation role.
Disclosure of Invention
The invention aims to overcome the technical problems and defects in the prior art and provide a novel damping base for a marine main engine.
In order to achieve the aim, the technical scheme adopted by the invention for achieving the aim is as follows:
the utility model provides a boats and ships host computer damping base, includes upper support piece 3 and lower floor's support piece 1 which characterized in that: left-right isolation symmetry is provided with respectively between upper support piece 3 and lower floor's support piece 1 with upper support piece 3 and lower floor's support piece 1 fixed connection's two multirow middle damping piece 2, middle damping piece 2 including be used for with support base 9 that lower floor's support piece 1 is connected support base 9 the upper plane is connected with open-top's hemisphere cavity damping cover 6, and open-top is connected with flange 5, install the gag lever post 7 that one end stretches into in 6 cavities of hemisphere cavity damping cover in the centre bore that flange 5 was equipped with, the other end of gag lever post 7 with upper support piece 3 is connected, it has a plurality of damping metal particle 8 still to fill in 6 cavities of hemisphere cavity damping cover.
Furthermore, the hemispherical cavity vibration reduction cover 6 is of a multi-lamination structure formed by an elastic metal diaphragm layer 6-1 and a metal wire mesh block layer 6-2 at intervals.
Furthermore, the multi-layer structure is at least 3 layers, namely an inner layer and an outer layer are elastic metal diaphragm layers 6-1, and a middle layer is a metal wire mesh block layer 6-2.
Further, the thickness of the elastic metal diaphragm layer 6-1 is 2-4mm, and the material is manganese alloy steel.
Further, the layer thickness of the metal wire mesh block layer 6-2 is 1mm, and the material is stainless steel.
Further, the diameter of the top opening of the hemispherical cavity damper cover 6 is 1/2 of the diameter of the lower opening.
Further, the distance between the limiting rod 7 and the supporting base 9 is 2/5 the length of the limiting rod 7 extending into the cavity of the hemispherical cavity vibration damping cover 6.
Further, the filling rate of the vibration-damping metal particles 8 is 60%.
Further, the vibration-damping metal particles 8 have a particle size of 3 to 4mm, are made of any one of tungsten carbide, ceramic, iron and lead, and have any one of a circular shape, an oval shape and an irregular shape.
The invention relates to a vibration damping method of a vibration damping base of a marine main engine, which specifically comprises the following steps:
s1, damping by an elastic metal diaphragm in the hemispherical cavity damping cover. The hemispherical cavity vibration damping cover is arranged to be of an approximate hemispherical structure with a small upper opening diameter and a large lower opening diameter and a certain radian, and a mechanical model formula is utilized:
and calculating the maximum bearing force of the elastic metal diaphragms according to the diaphragm spring, and determining the number of the diaphragms according to the bearing quality. The outer upper radius of the elastic metal diaphragm layer is R, the outer lower radius of the elastic metal diaphragm layer is R, the height of the elastic metal diaphragm layer is h, the thickness of the spring plate is t, the elastic modulus of the metal plate is E, the outer support radius is L, the inner support radius is iota, the Poisson ratio of the material is mu, the vertical deformation difference of the diaphragm spring relative to the original state is lambda when the diaphragm spring is subjected to external force, and the correction coefficient is A (obtained by looking up relevant elastic diaphragm documents).
When the machine vibrates, the elastic metal diaphragm can be simplified into a spring model by utilizing the self vibration damping function of the elastic metal diaphragm, and the force transmitted to the base by the machine before vibration isolation is F
q=F
0e
iwtThe force transmitted to the base after the elastic metal diaphragm is installed is
Coefficient of vibration isolation of
Calculated η is less than 1, and the metal diaphragm base has obvious vibration damping effect.
And S2, carrying out dry friction vibration reduction on the wire mesh block layer in the hemispherical cavity vibration reduction cover. When the machine vibrates, the metal wires of the metal wire mesh block layer 6-2 generate dry friction damping under the action of load due to slippage, so that the vibration energy of the system is absorbed and dissipated, and the purposes of buffering and vibration isolation are achieved. The mathematical expression for dry friction is: fS=μNsgn(Vrel) Wherein: mu is the friction coefficient of the contact surface; n is the positive pressure (N) of the contact surface;lVeris the relative velocity (m/s) of the two contact surfaces.
And S3, damping and vibration reduction of metal particles in the hemispherical cavity vibration reduction cover. A certain amount of metal particles are filled in the cavity of the vibration reduction cover with the hemispherical cavity, the particles are one of metal materials such as tungsten carbide, ceramics, iron, lead and the like, and the shape of the particles can be round, oval or irregular. When the structure vibrates, partial kinetic energy of the structure is transferred to the metal particles through the contact and collision of the structure and the metal particles, the metal particles move in the cavity of the vibrating structure, and then friction and collision occur among the particles and between the particles and the structure, the friction and collision effects lead to energy loss, the vibration energy of the vibrating structure is reduced, the vibration amplitude is reduced, and therefore the purpose of increasing the system damping is achieved.
According to the invention, the particle damping principle is fully utilized, the host vibration inevitably drives the limiting rod and the hemispherical cavity vibration reduction cover to move, so that the metal particles in the hemispherical cavity vibration reduction cover move, the friction collision among the particles, between the particles and the hemispherical cavity vibration reduction cover and between the particles and the limiting rod is generated, and the vibration energy of the host is effectively reduced.
In the specific implementation, the length of the base main body and the number of the intermediate damping pieces can be determined according to the positive pressure and the pressure bearing capacity generated by a host, and if necessary, rigid reinforcing ribs can be additionally arranged between the elastic metal diaphragm layers of the elastic metal diaphragm layers to improve the strength and the pressure bearing stability of the structure.
The ship main engine damping base provided by the invention has the advantages and beneficial effects that:
1. because the diaphragm wire mesh damping vibration attenuation principle is adopted, the passive damping function of the metal particles is fully utilized, and the diaphragm wire mesh damping vibration attenuation principle and the passive damping function are combined, the structural vibration generated by the excitation force of the ship main engine is effectively reduced, and the vibration attenuation effect is improved by 20% compared with that of a traditional rubber vibration attenuation base;
2. because the invention has the structure of the limiting rod, the structure of the limiting rod can realize the function of adjusting the limiting height, therefore, the invention can be used in cooperation with hosts with different qualities;
3. due to the adoption of the modular design, damaged parts can be replaced at any time, so that the production period is shortened by 30%, and the parts can be replaced with each other, thereby reducing the use cost.
4. Because the heat resistance of the metal elastic membrane and the metal particles, the metal elastic membrane can be suitable for the severe environment with high-temperature oil stains of ships, and has longer service life compared with a damping device adopting traditional damping devices such as rubber and the like.
Drawings
FIG. 1 is a schematic illustration of the construction of an embodiment of the present invention;
FIG. 2 is a left side view of FIG. 1;
FIG. 3 is a schematic view showing the construction of an intermediate damping member in the present invention;
FIG. 4 is a top view of FIG. 3;
FIG. 5 is a cross-sectional view of a hemispherical cavity damping cap in accordance with an embodiment of the present invention;
FIG. 6 is a view showing the outer shape of the stop lever according to the present invention;
FIG. 7 is a top plan view of a stop lever according to the present invention;
FIG. 8 is a top view of the flange of the present invention;
in the figure: 1. a lower support member; 2. an intermediate damping member; 3. an upper support member; 4. a top locking nut; 5. a flange; 6. a hemispherical cavity vibration reduction cover; 6-1, an elastic metal diaphragm layer; 6-2, a wire mesh block layer; 7. a limiting rod; 8. vibration damping metal particles; 9. a support base; 10. the base tightly locks the nut; 11 inner ribbed plate, 12 bottom nut; 13. a bottom bolt; 14. a top nut; 15. a top bolt; 16. a connecting bolt; 17 a protective cover; 18. supporting a vertical plate; 19. supporting channel steel; 20. i-shaped steel; 21. an outer rib.
Detailed Description
The present invention is further illustrated by the following more detailed description of the invention, taken in conjunction with the accompanying drawings, which are to be construed as illustrative only and not limiting of the scope of the invention, as defined in the appended claims, as modified in all equivalent forms thereof by those skilled in the art upon reading the present specification.
As shown in fig. 1 to 7: the invention relates to a damping base for a marine main engine, which comprises an upper layer supporting piece 3, a lower layer supporting piece 2 and a middle damping piece 1. The upper layer supporting piece 3 is composed of two supporting channel steel 19 and a plurality of supporting vertical plates 18 which are arranged in parallel, and the supporting vertical plates 18 are welded in concave grooves of the supporting channel steel 19 at equal intervals. The lower-layer supporting piece is composed of two I-shaped steels 20 which are arranged in parallel, and a plurality of inner rib plates 11 and outer rib plates 21 which are respectively welded on the inner side and the outer side of the lower-layer supporting piece at equal intervals, and the welding intervals of the inner rib plates 11 and the outer rib plates 21 are consistent with the welding intervals of the supporting vertical plates 18 in the upper-layer supporting piece 3. Middle damping piece 2 includes gag lever post 7, gag lever post 7 through upper end nut 16 with middle damping piece 2 with upper support piece 3 connects, gag lever post 7 wholly pass the centre bore of flange 5, utilize top lock nut 14 and flange fastening connection, upper end nut 16 outside is equipped with safety cover 17. Still include hemisphere cavity damping cover 6, hemisphere cavity damping cover 6 is the many stromatolite structures that are constituteed by 6-2 and the elastic metal diaphragm layer 6-1 interval of wire mesh layer, 6 tops of hemisphere cavity damping cover radially inwards extend the top stiff end, are connected with flange 5 through damping top bolt 15, top nut 14, 6 inside a plurality of damping metal balls 8 that are equipped with of hemisphere cavity damping cover, 6 bottoms of hemisphere cavity damping cover radially outwards extend the bottom stiff end, are connected with supporting base 9 through bottom bolt 13, bottom lock nut 10, middle damping 2 is connected with lower floor's support piece 1 through bottom bolt 13, bottom nut 12.
The flange bolt holes and the central holes of the flange 5 are both arranged in an inwards concave step shape, so that the upper surfaces of the top bolts 15 and the fastening bolts 4 are lower than the upper surface of the flange. The lower part of the central hole of the flange 5 is of an inner hexagonal structure, so that the limiting rod 7 is ensured not to rotate when the fastening nut 4 is fixed, as shown in fig. 8.
And a boss structure is arranged at the upper end of the limiting rod 7 and is matched with the fastening nut 4 for use. And a hexagonal structure is further arranged above the boss of the limiting rod 7 and is matched with a hexagonal hole in the central hole of the flange 5 for use, and the part of the limiting rod 7 extending into the cavity of the hemispherical cavity vibration reduction cover 6 is of a cylindrical structure, as shown in fig. 6.
The hemispherical cavity vibration reduction cover 3 is a multi-layer structural member with 3 layers, and comprises an elastic metal diaphragm layer 6-2 with the thickness of 2 layers being 2-4mm and a metal wire mesh block layer 6-1 with the thickness of 1 layer being 1mm, as shown in fig. 5.
The material of the vibration-damping metal particles 8 is iron.
The diameter D1 of the upper bottom surface of the hemispherical cavity vibration damping cover 6 is 1/2 of the diameter D2 of the lower bottom surface, as shown in FIG. 5.
The distance h between the limiting rod 7 and the supporting base 9 accounts for 2/5 the length of the limiting rod 7 extending into the cavity of the hemispherical cavity vibration damping cover 6, as shown in fig. 6.
The metal wire mesh block layer 6-1 is made of stainless steel, and the flange 5 is made of steel.
The flange 5 is specially designed with 6 stepped bolt holes with concave upper surfaces to ensure that the upper surface of the top bolts 15 is lower than the upper surface of the entire flange 5. Preferably 1 stepped flange central hole with an inner concave upper surface is used for ensuring that the upper surface of the top locking bolt 4 is lower than the upper surface of the whole flange 5, and the contact part of the central bolt hole and the limiting rod is arranged to be of an inner hexagonal structure.
Preferably, the support base 9 is provided with 6 stepped bolt holes with concave lower bottom surfaces to ensure that the upper surface of the bottom lock nut 10 is lower than the lower surface of the entire support base 9.
The corresponding preferred bolt hole number of 6 top stiff ends of hemisphere cavity damping cover and bottom stiff end, its aperture with flange 5 and bolt aperture on the support base cooperatees.
The invention discloses a vibration reduction principle of a vibration reduction base of a marine main engine, which comprises the following steps:
1. the support effect of the elastic metal diaphragm layer in the hemispherical cavity vibration reduction cover is utilized, the hemispherical cavity vibration reduction cover is set to be an approximate hemispherical cavity structure with a small upper bottom surface radius and a large lower bottom surface radius and a certain radian, and the vibration reduction effect on the ship main engine is effectively achieved. The formula can be derived from the mechanical model a-L of the diaphragm spring.
The outer upper radius of the elastic metal diaphragm layer is R, the outer lower radius of the elastic metal diaphragm layer is R, the height of the elastic metal diaphragm layer is h, the thickness of the spring plate is t, the elastic modulus of the metal plate is E, the outer support radius is L, the inner support radius is iota, the Poisson ratio of the material is mu, the vertical deformation difference of the diaphragm spring relative to the original state is lambda when the diaphragm spring is subjected to external force, and the correction coefficient is A (obtained by looking up relevant elastic diaphragm documents). The force which can be borne by a single elastic metal membrane can be calculated according to the formula, and then the requirement that a plurality of elastic metal membranes can support the machine can be deduced according to the mass of the machine. Meanwhile, when the machine moves, the elastic metal diaphragm can be simplified into a spring model by utilizing the self vibration damping effect of the elastic metal diaphragm, and the force transmitted to the base by the machine before vibration isolation is F
q=F
0e
iwtThe force transmitted to the base after the elastic metal diaphragm is installed is
So that the vibration isolation coefficient is
Calculated η is less than 1, and the metal diaphragm base has obvious vibration damping effect.
2. And the dry friction vibration reduction of the metal wire mesh block in the hemispherical cavity vibration reduction cover is utilized. Of dry frictionThe mathematical expression is: fS=μNsgn(Vrel) Wherein: mu is the friction coefficient of the contact surface; n is the positive pressure (N) of the contact surface;lVeris the relative velocity (m/s) of the two contact surfaces. The metal wire mesh block generates dry friction damping due to slippage among wires under the action of load, so that the vibration energy of a system is absorbed and dissipated, and the purposes of buffering and vibration isolation are achieved. Its advantages are high load-bearing power, stable performance, high environmental adaptability and long service life.
3. The damping function of the vibration-damping metal particles is utilized. Particle damping is to process independent cavities attached to a vibrating structure at appropriate positions inside the structure, and fill a certain amount of particles or powder materials into the cavities, wherein the particles are usually metal materials such as tungsten carbide, ceramic, iron or lead, and the shape of the particles can be round, oval or irregular. When the structure vibrates, partial kinetic energy of the structure is transferred to the particles through the contact and collision of the structure and the particles, the particles move in the cavity of the vibrating structure, and then friction and collision are generated among the particles and between the particles and the structure, the friction and collision effects lead to energy loss, the vibration energy of the vibrating structure is reduced, the vibration amplitude is reduced, and therefore the purpose of increasing the system damping is achieved. According to the invention, the particle damping principle is fully utilized, the host vibration inevitably drives the limiting rod and the hemispherical cavity vibration reduction cover to move, so that the metal particles in the hemispherical cavity vibration reduction cover move, the friction collision among the particles, between the particles and the hemispherical cavity vibration reduction cover and between the particles and the limiting rod is generated, and the vibration energy of the host is effectively reduced.
In the specific implementation, different numbers of the intermediate damping members 2 can be used according to the application.
In specific implementation, the elastic metal diaphragm layers 6-2 in the hemispherical cavity vibration reduction cover 6 are main vibration reduction parts, the number of the elastic metal diaphragm layers can be selected according to the actual condition of a host, and the number of the metal wire mesh block layers 6-1 is correspondingly added.
In addition to the above embodiments, the present invention may have other embodiments, and any technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of the claims of the present invention.