KR101701150B1 - High/low type hydraulic top bracing for reducing the vibration from engine - Google Patents

Abstract

The present invention relates to a high/low type hydraulic top bracing for reducing vibration of a marine engine which reduces transverse vibration generated by driving a marine engine and, in particular, switches pressure of the top bracing into a low mode to change a natural frequency by giving a change to a stiffness value when resonance occurs between the engine vibration and other vibrations (hull vibration, shaft vibration, etc.), thereby minimizing the vibration transmitted to the hull from the engine while having a very simple structure, and not generating leakage of oil by strengthening a sealing between a cylinder and a ram.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a high / low type hydraulic top bracing for vibration damping of a ship engine,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic tower bracing, and more particularly, to a hydraulic bracing system that is installed between a marine engine and a hull to attenuate lateral vibration generated from the engine, Low-type hydraulic top bracing for vibration damping of a marine engine which is capable of minimizing vibration transmitted to the hull from the engine by switching to have a low stiffness value.

The propulsive force of the ship is caused by the propulsive shafts rotating by the driving force due to the explosive force in the engine cylinders, and many vibrations are generated by various factors. Especially, in the engine, the piston and the connecting rod are moved up and down, The inertial force of the reciprocating motion generated in the axial direction of the cylinder, the inertial force due to the rotational motion of the crankshaft connected to the piston through the connecting rod, and the cyclic change of the rotational force applied to the crankshaft, .

Since the engine of a large-sized ship has a large output, when the vibration of the ship engine is directly transmitted to the hull, the vibration of the hull is increased, thereby promoting the fatigue failure of the ship and the structure. It causes serious safety problems. Therefore, a method of mitigating the vibration of the engine installed on the ship has been sought. One of the most commonly used methods is to prevent the ship engine from oscillating in the lateral direction, It is a method of installing a structure called top brassing.

Top bracing is installed so as to connect the top and peripheral structures of the engine to each other, and is installed to extend along the lateral direction of the ship in a horizontal posture. These top bracing include friction top bracing and hydraulic top bracing. In order to attenuate the lateral vibration generated between the engine and the hull, the engine and the peripheral structure are connected to steel bars, and the ends of the steel bars and the peripheral structures are connected to each other through a friction plate. And is configured to attenuate the vibration of the engine by frictional force. However, the friction type is advantageous in that the structure is simply formed in a state that the structure is fixed in a state of no fluidity, but since it has a large rigidity, external force causes self cracking or cracking of the surrounding structure And the friction plate hardly cushions the vibration of the engine and does not act actively against vibrations that vary with the load of the engine.

The hydraulic type top bracing comprises a hydraulic cylinder connected to the engine, a piston incorporated in the hydraulic cylinder and connected to the peripheral structure, and an accumulator. The accumulator automatically adjusts the hydraulic pressure in the hydraulic cylinder according to the frequency of the excitation force generated by the engine. The hydraulic type is advantageous in that the strength against impact is strong and vibration buffering and resonance avoidance are possible, There is a problem in that the structure and the operation mechanism are complicated.

As an example of a hydraulic top bracing technique, the disclosure of Japanese Patent Laid-Open Publication No. 2016-92312 entitled "Hydraulic Top Bracing Apparatus Providing Low Stiffness Value" discloses a structure in which the engine and the hull are freed to reduce the amplitude occurring in the transverse direction To provide a low stiffness value.

However, the patented technique has the following problems. First, since the sealing between the cylinder and the piston is weak, the oil in the main chamber may leak, resulting in a problem that the function of the top bracing can not be properly performed.

Second, since the hydraulic line is divided into a low-pressure circuit and a high-pressure circuit, and the accumulator is separately divided into high-pressure and low-pressure lines, the apparatus itself is complicated, and the types and the number of valves are large. There is a problem that there is a high possibility that a failure will occur.

Third, there is a surface contact between the end of the piston rod and the flange of the engine side and the piston pilot. If necessary, there is no separate structure for injecting the grease. But also there are many problems such as grease leaking between the piston rod, the flange and the piston, and penetration of dust or various foreign substances.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to reduce the lateral vibration generated due to the driving of a marine engine, The vibration of the top bracing is changed to low and the stiffness is changed to change the natural frequency so that the vibration transmitted to the hull from the engine is minimized and the structure is very simple. Low-type hydraulic top bracing for vibration damping of a marine engine which does not cause leakage by enhancing the sealing of the marine engine.

A high / low type hydraulic tower bracing for vibration damping of a marine engine according to the present invention comprises: a cylinder having one end coupled to a hull structure; A ram for moving in the back and forth direction in the cylinder and forming a main chamber inside the cylinder; A lock nut whose one end is in spherical contact with an engine-side end portion of the ram; A bearing cover having one end coupled to the engine; A piston rod whose one end is in spherical contact with a hull-side end portion of the bearing cover; A transfer barrier in which one end is engaged with the piston rod and the other end is engaged with a lock nut; A valve manifold connected to the main chamber, the valve manifold including a relief valve, a solenoid valve, and a check valve; And an accumulator connected to the valve manifold and adjusting the pressure of the nitrogen gas filled in the main chamber according to the oil pressure. When resonance occurs between the engine and the hull, The pressure is switched to low so as to change the stiffness value to change the natural frequency so as to minimize the vibration transmitted to the hull from the engine.

Preferably, the accumulator includes an oil chamber filled with oil and connected to the valve manifold; A chamber made of rubber is filled with nitrogen gas having a predetermined pressure, and a gas chamber for applying pressure or absorbing pressure to the oil chamber.

Preferably, a protector for sealing a space formed between the outer circumferential surface of the lock nut and the inner circumferential surface of the end portion of the ram of the engine and between the inner circumferential surface of the end surface of the bearing cover and the outer circumferential surface of the piston rod is further coupled, A bellows rubber having both ends inserted between the outer circumferential surface of the lock nut and the inner circumferential surface of the ram end portion and between the inner circumferential surface of the end portion of the bearing cover and the outer circumferential surface of the piston rod and having elasticity and elasticity; An O-ring inserted into a groove formed in an outer circumferential surface of the lock nut and an outer circumferential surface of the piston rod, respectively, and pressed by one end of the bellows rubber; And a spring inserted into the groove formed in the inner circumferential surface of the end portion of the ram and the inner circumferential surface of the end portion of the bearing cover while the other end of the bellows rubber is bent and inserted into the bent portion.

Preferably, when the oil pressure in the main chamber is higher than a predetermined pressure, the nitrogen gas in the gas chamber provided in the accumulator is operated to absorb the pressure. When the oil pressure in the main chamber becomes lower than a predetermined pressure, Is operated to increase the oil pressure by applying a force to the oil chamber.

The hydraulic top bracing for vibration damping of a marine engine according to the present invention absorbs the lateral vibration generated due to the driving of the marine engine, and particularly when resonance occurs between the engine vibration and other vibrations (hull vibration, shaft vibration, etc.) By changing the pressure of the top bracing to low and varying the stiffness value to change the natural frequency, the vibration transmitted to the hull from the engine is minimized, and the durability of the structure as well as the safety of the ship can be remarkably improved.

The hydraulic top bracing according to the present invention is constituted by an O-ring and a bellows rubber between an end portion of a joint portion of a transmission pulverizer and a bearing cover and a joint portion between a lock nut and a ram. The transporter can be flexibly deformed. Therefore, even if the transporter's position and angle change with the engine side or the hull side, the protector actively copes with deforming the shape, causing foreign matter to flow into the gap, Oil) is prevented.

Since the grease can be injected through the piston rod if necessary, and the grease groove is formed at each end of the rounded transfer ferrule and the lock nut, the gap between the bearing cover and the ram It minimizes friction between each end of the transfer ferrule and lock nut and the bearing cover and the ram, thus preventing wear.

1 is a view showing a state in which a tower bracing according to the present invention is mounted on a ship.
FIG. 2 is a sectional view showing a part of FIG. 1; FIG.
3 is a schematic cross-sectional view showing the operating relationship of the top bracing according to the present invention in the case where a force is applied to the hull from the engine in a state of being switched to low.
4 is a schematic cross-sectional view showing the operating relationship of the top bracing according to the present invention in the case where no force is applied to the hull from the engine.
5 is a sectional view showing the accumulator.

The most significant technical feature of the hydraulic top bracing according to the present invention is that when resonance occurs between engine vibration and other vibrations (hull vibration, shaker vibration, etc.) at a certain rpm, the top bracing is operated in a high / And the durability of the structure is remarkably improved as well as the safety of the ship.

The top bracing according to the present invention is installed between the engine of the ship and the hull so as to attenuate vibrations caused by the driving of the engine. In particular, when resonance occurs between the engine vibration and other vibrations (hull vibration, shaft vibration, etc.) It is a device for minimizing vibration transmitted from the engine to the hull and from the hull to the engine by operating in high / low mode.

A top bracing 10 according to the present invention includes a cylinder 11 having one end coupled to a hull structure, a ram 12 moving in the longitudinal direction in the cylinder 11, A bearing cover 16 having one end coupled to the engine side; a piston rod 15 coupled to an end of the bearing cover 16 at the hull side; A transfer valve 14 connected to the lock nut 13 and the piston rod 15, a valve manifold 18 connected to the main chamber 111 formed in the cylinder, a valve manifold 18, An accumulator 19 connected thereto, and a control unit 20 for controlling the overall operation.

The ram 12 is moved in the back and forth direction in the cylinder 11 to form a main chamber 111 inside the cylinder and the oil supplied from the accumulator 19 is filled in the main chamber 111 Pressure. The end portion of the ram 12 on the side of the engine is in spherical contact with the lock nut 13 whose end portion is formed as a spherical surface. Reference numeral 121 denotes a sealing provided between the inner wall of the cylinder 11 and the outer peripheral surface of the ram 12. In order to secure the function of the top bracing, In order to completely prevent leakage, the present invention is installed in triple.

One end of the bearing cover 16 is coupled to the engine side, and the end portion on the side of the hull is formed into a spherical surface to make a spherical surface contact with the piston rod 15 whose end is formed as a spherical surface. One end of the transfer barrier 14 is coupled to the piston rod 15 and the other end of the transfer barrier 14 is coupled to the lock nut 13 to connect them integrally.

A lock nut 13 is formed which is in spherical contact with an end portion of the ram 12 on the engine side and is provided with a grease inlet 152 for injecting grease through the piston rod 15 and the transfer perforator 14. [ And grease grooves 131 and 151 are formed along the spherical surfaces at the ends of the piston rod 15 that are in spherical contact with the end portions of the bearing cover 16 at the hull side, Which reduces the friction of the contact area and reduces wear.

Since there is a gap between the outer circumferential surface of the lock nut 13 and the inner circumferential surface of the end portion of the engine 12 of the ram 12 and between the inner circumferential surface of the end portion of the bearing cover 16 and the outer circumferential surface of the piston rod 15, It is preferable that the protector 17 is joined to seal the space (gap) because the grease is leaked through the space (gap) and various foreign substances are penetrated. In order to actively cope with the change in the gap, the protector 17 is formed to have an elasticity and an elasticity so that the angle and the position of the piston rod 15 change according to the operation of the top bracing 10, It should be resilient.

The protector 17 is provided with an O-ring 172 and a spring 173 at both ends of the bellows rubber 171. Both ends of the bellows rubber 171 are fixed to the outer circumferential surface of the lock nut 13, Is inserted between the inner circumferential surface of the end portion of the bearing cover 16 and the inner circumferential surface of the end of the bearing cover 16 and the outer circumferential surface of the piston rod 15 and is not a plate member but has elasticity and elasticity, It has the same shape as the bellows.

The O-ring 172 is inserted into the groove formed in the outer circumferential surface of the lock nut 13 and the outer circumferential surface of the piston rod 15 so as to be compressed by the one end of the bellows rubber 171, The other end of the bellows rubber 171 is inserted into the groove formed in the inner circumferential surface of the end of the ram 12 and the inner circumferential surface of the end of the bearing cover 16 and inserted into the bent portion.

The valve manifold 18 is connected to the main chamber 111 and is provided with valves for controlling the hydraulic pressure. The valve manifold 18 includes a relief valve 181 that functions to lower the pressure when a predetermined or higher pressure is applied, A solenoid valve 182 for converting the top bracing to high / low, a check valve 183 for allowing the oil to move only in one direction, and a pressure trans- mitter 184 for generating an alarm signal when the pressure falls below a predetermined pressure, The structure is very simple. The reference numeral 20 is a control section for controlling all operations of the top bracing including the valve manifold 18. [

The hydraulic pressure in the main chamber 111 is maintained at a constant level (for example, 49 kg / cm 2) or less. When the pressure becomes higher, the relief valve 181 is opened and the oil flows out toward the accumulator 19, When the oil pressure in the main chamber 111 drops below a certain level (for example, 10 kg / cm 2), the oil is introduced through the check valve 183 from the accumulator 19 to increase the pressure. When resonance occurs between the engine vibration and other vibrations (hull vibration, shaft vibration, etc.), the oil moves through the solenoid valve 182 to the oil chamber 192, and nitrogen gas filled in the gas chamber 191 By actively absorbing the pressure and changing the pressure of the top bracing to low to change the stiffness value, it works to minimize vibration transmitted from the engine to the hull by changing the natural frequency.

The accumulator 19 is provided with a gas chamber 191 made of rubber filled with a nitrogen gas at a predetermined pressure so that the gas chamber 191 is expanded and contracted while the gas chamber 191 is expanded and contracted. Nitrogen gas absorbs the pressure and emits it again. More specifically, when the oil pressure in the main chamber 111 is increased, the nitrogen gas in the gas chamber 191 absorbs the pressure of the oil. On the contrary, when the oil pressure in the main chamber 111 is lowered, The gas acts to increase the pressure of the oil while applying pressure to the oil.

3 and 4, when a force lower than the set pressure of the relief valve 181 is applied to the top bracing from the hull or the engine, the operation of the top bracing according to the present invention will be described. The hydraulic pressure is increased, and this pressure sustains the lateral vibration of the engine.

When a force greater than the pressure set on the relief valve 181 is applied, the relief valve 181 is opened and the oil in the main chamber 111 is poppet valve, The nitrogen gas in the gas chamber 191 made of rubber is compressed while the oil is being moved, so that the pressure is absorbed by the accumulator 19, The force is absorbed.

In the case of receiving a reverse load, that is, when the engine or the hull is distant from each other, the hydraulic pressure in the main chamber 111 is reduced. At the same time, the compressed nitrogen gas in the gas chamber 191 expands while pushing the rubber wall of the gas chamber 191 and pushes it toward the oil chamber 192, so that the oil in the oil chamber 192 returns to the check valve 183 And flows into the main chamber 111 through the through-

When resonance occurs between the engine vibration and other vibrations (hull vibration, shaft vibration, etc.), the oil moves to the oil chamber 192 of the accumulator through the solenoid valve 182 and the nitrogen charged in the gas chamber 191 The gas acts to minimize the vibration transmitted to the hull from the engine by changing the natural frequency by changing the stiffness value by converting the pressure of the top bushing to low while absorbing the pressure.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Various modifications and variations will be possible without departing from the spirit of the invention. Therefore, the scope of the present invention should be construed as being covered by the scope of the appended claims, and technical scope within the scope of equivalency thereof should be construed as being included in the scope of the present invention.

10: Top Bracing
11: cylinder 111: main chamber
12: ram 121: sealing
13: Lock nut 131: Grease groove
14: transfer barrier
15: piston rod 151:
152: Grease inlet
16: Bearing cover
17: Protector 171: Bellows rubber
172: O-ring 173: spring
18: Valve manifold 181: Relief valve
182: Solenoid valve 183: Check valve
184: Pressure Transmitter
19: Accumulator 191: Gas chamber
192: Oil chamber 193: Poppet valve
20:

Claims (6)

A hydraulic top bracing for vibration damping generated by driving an engine installed between an engine of a ship and a hull,
The top bracing comprises:
A cylinder having one end coupled to the hull structure;
A ram for moving in the back and forth direction in the cylinder and forming a main chamber inside the cylinder;
A lock nut whose one end is in spherical contact with an engine-side end portion of the ram;
A bearing cover having one end coupled to the engine;
A piston rod whose one end is in spherical contact with an end portion of the bearing cover on the side of the hull;
A transfer barrier in which one end is engaged with the piston rod and the other end is engaged with a lock nut;
A valve manifold connected to the main chamber, the valve manifold including a relief valve, a solenoid valve, and a check valve;
An accumulator connected to the valve manifold and adapted to regulate the pressure of nitrogen gas filled in the main chamber according to the oil pressure;
And,
A protector for sealing a space formed between an outer circumferential surface of the lock nut and an inner circumferential surface of an end portion of a ram of the ram and between the inner circumferential surface of the end portion of the bearing cover and the outer circumferential surface of the piston rod,
The protector includes:
A bellows rubber having both ends inserted between the outer circumferential surface of the lock nut and the inner circumferential surface of the ram end portion, between the inner circumferential surface of the bearing cover end portion and the outer circumferential surface of the piston rod, and having elasticity and elasticity;
An O-ring inserted into a groove formed in an outer circumferential surface of the lock nut and an outer circumferential surface of the piston rod, respectively, and pressed by one end of the bellows rubber;
A spring inserted into the groove formed in the inner circumferential surface of the end portion of the ram and the inner circumferential surface of the end portion of the bearing cover while the other end of the bellows rubber is bent and inserted into the bent portion;
Lt; / RTI >
Characterized in that when the resonance occurs between the engine and the hull, the pressure of the top bracing is switched to low so as to change the rigidity value to change the natural frequency so as to minimize the vibration transmitted to the hull from the engine. High / low type hydraulic top bracing for engine vibration damping.
2. The accumulator as claimed in claim 1,
An oil chamber filled with oil and connected to the valve manifold;
A gas chamber filled with a nitrogen gas having a predetermined pressure inside the chamber made of rubber and applying pressure or absorbing pressure to the oil chamber;
And a high / low type hydraulic top bracing for vibration damping of a marine engine.
delete The method according to claim 1,
Low pressure type hydraulic top bracing for vibration damping of a marine engine, characterized in that when the oil pressure in the main chamber becomes higher than a certain pressure, nitrogen gas in the gas chamber provided in the accumulator operates to absorb the pressure.
The method according to claim 1,
Wherein when the oil pressure in the main chamber is lower than a predetermined pressure, nitrogen gas in the gas chamber provided in the accumulator acts on the oil chamber to increase the oil pressure by increasing the oil pressure. Top bracing.
The method according to claim 1,
And a piston groove which is in spherical contact with a hull side end portion of the bearing cover is formed with a grease groove along the spherical surface, High / Low Type Hydraulic Top Bracing.

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