JP3664844B2 - Tie bolt structure of internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tie bolt structure in an internal combustion engine in which a jacket, a frame, and a base plate are integrally tightened with a long tie bolt, such as a large diesel engine.
[0002]
[Prior art]
In a crosshead type large diesel engine, since the overall height of the engine is extremely large, a jacket, a frame, and a base plate are tightened and integrated with a tie bolt that penetrates in common to maintain a required rigidity.
FIG. 10 shows an example of a large crosshead type diesel engine equipped with such tie bolts.
In FIG. 10, 2 is a piston, 3 is a crosshead, 5 is a crankshaft, 22 is a combustion chamber, and the explosive force P in the combustion chamber 22 is via the piston 2, piston rod 1 crosshead 3 and connecting rod 4. It is transmitted to the crankshaft 5 and taken out from the end of the crankshaft 5 as engine output.
[0003]
Reference numeral 6 is a jacket, 8 is a frame, and 7 is a base plate. The jacket 6, the frame 8 and the base plate 7 are tightened with nuts 23 and 26 of tie bolts 9 inserted into tie bolt holes 24 formed in these. To improve the rigidity.
As shown in FIG. 10, one tie bolt 9 is provided on each side of the cylinder, and in the axial direction, between the cylinders and on both sides of the first row cylinder and the last row cylinder.
[0004]
FIG. 11 shows a conventional example of a tie bolt structure in the crosshead large diesel engine.
In FIG. 11, 11 is a tie bolt chamber, which is formed between the outer periphery 9c of the tie bolt 9 and the inner periphery of the tie bolt hole 24 formed concentrically and with the same diameter in the jacket 6, the frame 8, and the base plate 7. The engine lubricating oil as the viscous fluid 12 is supplied to the inside.
Reference numerals 23 and 26 denote nuts for tightening both ends of the tie bolt 9. Reference numeral 10 denotes an oil pan.
[0005]
During operation of a large diesel engine having such a tie bolt structure, as shown in FIG. 10, the reaction force P ₁ of the explosive force P in the combustion chamber 22 acts on the cylinder jacket 6, and the jacket 6, frame 8 and upwardly to act base plate 7 as a separating force applied for a minimum of one another, comprising the P ₁ that tie bolts 9 are responsible. Accordingly, the tensile stress corresponding to P ₁ acts as a static stress on the tie bolt 9.
[0006]
On the other hand, in such a large diesel engine, since the height of the engine is large, the horizontal engine vibration is large. For this reason, the horizontal vibration acts on the tie bolt 9, and the tie bolt 9 resonates in the horizontal direction. When this resonance occurs, repeated bending stress due to resonance is superimposed on the static tensile stress (average stress).
Therefore, in such a large diesel engine, in order to prevent the occurrence of resonance due to such horizontal vibration, the viscous fluid 12 is supplied into the tie bolt chamber 11 as described above, and vibration is generated by the viscous frictional resistance thereof. Attenuated.
[0007]
[Problems to be solved by the invention]
After assembly of the engine, the tie bolt 9 may be temporarily disassembled when shipped to a delivery destination, or may be removed for periodic maintenance work even during use of the engine.
Therefore, in order to discharge or reinject the viscous fluid 12 at that time, in such a large diesel engine, it is necessary to use the viscous fluid 12 having a low viscosity to some extent, that is, having a low vibration damping effect. is there.
In addition, it is necessary to take care so that the amount of the viscous fluid 12 does not naturally decrease due to leakage, evaporation, etc. On the other hand, even if the viscous fluid leaks into the engine, It must be something that does not adversely affect driving.
[0008]
However, in the large diesel engine having the tie bolt structure according to the prior art shown in FIG. 11, the lubricating oil of the engine is supplied into the tie bolt chamber 11 as the viscous fluid 12 in view of the above-described circumstances. Since such a lubricating oil has a low viscosity, it cannot provide a sufficient vibration damping action as will be described below.
That is, FIG. 12 shows a state where the tie bolt 9 is resonating. As shown in FIG. 12 (A), when the tie bolt 9 receives the horizontal vibration f of the engine and tries to resonate as shown by W in FIG. 12 (B), XX in FIG. 12 (A). As shown in the arrow view (C), the tie bolt 9 moves in a direction approaching the wall of the tie bolt chamber 11. Therefore, low lubricant 12a of sandwiched therebetween viscosity would flow out to readily opposite side through the large gap A _1, surface pressure F ₁ pushing back the tie-bolts 9 to the opposite side is small.
Therefore, such large di - In diesel engines, for the outflow of the viscous fluid (lubricating oil) 12a from the gap A _1, it is difficult to sufficiently attenuate the horizontal vibration of the tie bolts 9, thus Setsuson is It often happens.
[0009]
In view of the problems of the prior art, the present invention provides a tie-bolt structure for an internal combustion engine that can sufficiently prevent vibration of the tie bolt and prevent occurrence of damage to the tie-bolt due to resonance even as a low-viscosity viscous fluid such as lubricating oil. The purpose is to provide.
[0010]
[Means for Solving the Problems]
In order to solve such a problem, the present invention inserts a tie bolt into a tie bolt hole drilled in communication with a jacket, a frame, and a base plate and tightens the nut with a nut to fix the jacket, the frame, and the base plate integrally. In an internal combustion engine in which a low-viscosity viscous fluid such as lubricating oil is sealed in a tie bolt chamber formed between the outer periphery of the tie bolt and the inner periphery of the tie bolt hole,
In the vicinity of the part where the amplitude due to the resonance of the tie bolt is maximized, an enlarged diameter part having an outer diameter larger than other parts in a certain length range is provided, and the outer periphery of the tie bolt and the inner periphery of the tie bolt hole When the tie bolt resonates, the surface pressure of the viscous fluid in the small gap portion is increased when the tie bolt resonates so that the gap of the tie bolt is excessively small due to the resonance. characterized by amplitude configured as allowed to decrease, for example, the enlarged diameter portion you characterized in that it is constructed by press-fitting the annular bush tie bolts periphery.
[0011]
According to this invention, when the tie bolt causes resonance due to horizontal vibration, the tie bolt is caused by the resonance in the enlarged portion of the tie bolt in which the gap between the outer periphery of the tie bolt and the inner periphery of the tie bolt hole is locally narrowed. When displacing in the horizontal direction, the viscous fluid receives a large resistance as it passes through this narrow gap. Due to this resistance force, a high surface pressure is generated in the gap, and this surface pressure tends to reduce the gap. This acts in a direction to stop the displacement, and the excessive amplitude due to the resonance is reduced.
Therefore, according to this invention, even if a low-viscosity engine lubricating oil is used for the viscous fluid, a vibration damping effect as great as that of the highly viscous fluid can be obtained.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Only.
[0013]
1 to 3 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a tie bolt mounting portion, FIG. 2 is an enlarged view of a Z portion in FIG. 1, and FIG.
FIG. 10 is a configuration diagram in the vicinity of a tie bolt mounting portion of a large diesel engine to which the present invention is applied.
In FIG. 10, 2 is a piston, 3 is a crosshead, 5 is a crankshaft, 22 is a combustion chamber, and the explosive force P in the combustion chamber 22 causes the piston 2, piston rod 1 crosshead 3 and connecting rod 4 to move. To the crankshaft 5 and is taken out as an engine output from the shaft end of the crankshaft 5.
[0014]
Reference numeral 6 is a jacket, 8 is a frame, and 7 is a base plate. The jacket 6, the frame 8 and the base plate 7 are tightened with nuts 23 and 26 of tie bolts 9 inserted into tie bolt holes 24 formed in these. It is integrated and the rigidity is improved.
As shown in FIG. 10, one tie bolt 9 is provided on each side of the cylinder, and in the axial direction, between the cylinders and on both sides of the first row cylinder and the last row cylinder.
The above basic configuration is the same as that of the prior art.
[0015]
1 and 2 showing the first embodiment of the present invention, reference numeral 11 denotes a tie bolt chamber, which is formed concentrically and with the same diameter in the outer periphery 9c of the tie bolt 9, the jacket 6, the frame 8, and the base plate 7. The tie bolt hole 24 is formed between the inner periphery of the tie bolt hole 24, and engine lubricating oil as the viscous fluid 12 is supplied to the inside thereof.
Reference numerals 23 and 26 denote nuts for tightening both ends of the tie bolt 9. Reference numeral 10 denotes an oil pan.
[0016]
The tie bolt 9 is provided with an enlarged diameter portion 9a having an outer diameter larger than that of other portions within a certain length in the vicinity of the portion where the amplitude due to resonance at the intermediate portion of Z is maximized. As shown in FIG. 2, the gap A between the outer periphery 9b of the enlarged diameter portion 9a and the inner periphery of the tie bolt hole 24 is formed to be sufficiently smaller locally than other portions.
[0017]
The operation of the large diesel engine provided with the tie bolt 9 having such a structure will be described with reference to FIG.
When the tie bolt 9 is subjected to horizontal engine vibration f and attempts to resonate in a mode such as W ₁ shown in FIG. 3B, the tie bolt 9 is viewed in the direction of arrows XX in FIG. As shown in (C), the tie bolt 9 and the tie bolt hole 24 are moved closer to each other in a direction approaching the inner surface of the tie bolt chamber 11, that is, the inner peripheral surface of the tie bolt hole 24.
[0018]
In the embodiment of the present invention, the tie bolt 9 is formed with the enlarged diameter portion 9a. Therefore, as shown in FIG. 3C, the viscous fluid 12 in the tie bolt chamber 11 is caused to move to the enlarged diameter portion by the horizontal displacement. It tries to flow out through a gap A between the outer periphery 9 b of 9 a and the inner periphery of the tie bolt hole 24.
At this time, the surface pressure F is generated by the resistance when the viscous fluid 12 flows out through the minute gap A.
This surface pressure F becomes a force that pushes back the tie bolt 9 in a direction opposite to the direction in which the tie bolt 9 vibrates, thereby suppressing the vibration of the tie bolt 9. Thereby, even if it is a viscous fluid with low viscosity like engine lubricating oil, a sufficiently large vibration damping effect can be obtained by adjusting the amount of the gap A.
[0019]
4 and 5 show a second embodiment of the present invention.
In this embodiment, the tie bolt 9 has an equal diameter, and an annular bush 14 is press-fitted into the outer periphery of the same portion of the tie bolt 9 as the enlarged diameter portion 9a in the first embodiment (FIGS. 1 and 2).
The bush 14 is made of a relatively soft metal such as a copper alloy or an aluminum alloy, or a resin material. In this case, the amount of the minute gap A formed between the outer periphery 14a of the bush 14 and the inner periphery of the tie bolt hole 24 is approximately the same as that in the first embodiment.
[0020]
In the second embodiment, the enlarged diameter portion can be configured by separately manufacturing and press-fitting a simple-shaped bush 14 without increasing the material diameter of the tie bolt 9 as in the first embodiment. Since it can, it becomes low cost.
When an excessive horizontal amplitude is generated in the tie bolt 9, the bush 14 made of a soft material comes into contact with the tie bolt hole 24 and serves as a protective member, so that the surface of the tie bolt 9 is not damaged.
[0021]
6 and 7 show a comparative embodiment of the present invention.
In this embodiment, the tie bolt 9 has an equal diameter, and a reduced diameter portion 25 having an inner diameter reduced over a certain length is provided in a part of the tie bolt hole 24.
The position in the longitudinal direction of the reduced diameter portion 25 is the same as the enlarged diameter portion 9a in the first embodiment. In addition, the amount of the minute gap A between the inner periphery 25a of the reduced diameter portion 25 and the outer periphery 9c of the tie bolt 9 is approximately the same as that in the first embodiment.
In this embodiment, when a steady rest bush (not shown) is fitted on the outer periphery of the tie bolt 9 above the position corresponding to the reduced diameter portion 25, the reduced portion 25 prevents the bush from falling. It functions as a stopper.
[0022]
8 and 9 show a third embodiment of the present invention.
This embodiment is a second embodiment shown in FIGS. 4 and 5, in which a combination of a comparative example are shown in FIGS. 6 and 7, as well as press fit the bushing 14 to the outer circumference of the tie bolts 9, tie bolt holes A reduced diameter portion 25 is provided on the inner periphery of 24.
In this case, both the effects of the second embodiment and the comparative embodiment are provided.
[0023]
In addition, in 2nd thru | or 3rd embodiment shown in FIG. 4 thru | or FIG. 9, and a comparison form , the same member as 1st Embodiment is shown with the same code | symbol.
[0024]
【The invention's effect】
As described above, according to the present invention, the gap between the outer periphery of the tie bolt and the inner periphery of the tie bolt hole is configured to be locally small in the length direction of the tie bolt. When the viscous fluid passes through the minute gap, a large resistance force in the direction opposite to the vibration direction of the tie bolt is generated, and the vibration can be attenuated by this resistance force.
[0025]
Thereby, even if a low-viscosity lubricating oil is used for the viscous fluid, a large vibration damping effect equivalent to that of the high-viscosity fluid can be obtained, and the occurrence of tie bolt breakage due to resonance can be prevented.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a tie bolt structure for a large diesel engine according to an embodiment of the present invention.
FIG. 2 is an enlarged view of a portion Z in FIG.
FIG. 3 is an operation explanatory diagram of the first embodiment.
FIG. 4 is a view corresponding to FIG. 1 showing a second embodiment of the present invention.
FIG. 5 is an enlarged view of a Z part in FIG. 4;
FIG. 6 is a view corresponding to FIG. 1 showing a comparative embodiment of the present invention.
FIG. 7 is an enlarged view of a Z part in FIG. 6;
FIG. 8 is a view corresponding to FIG. 1 showing a third embodiment of the present invention.
FIG. 9 is an enlarged view of a portion Z in FIG.
FIG. 10 is a configuration diagram showing a tie bolt mounting structure in a large diesel engine.
FIG. 11 is a view corresponding to FIG. 1 showing a conventional tie bolt mounting structure for a large diesel engine.
12 is an operation explanatory diagram of the prior art shown in FIG.

Claims (2)

A tie bolt is inserted into a tie bolt hole drilled in communication with the jacket, frame, and base plate and tightened with a nut to fix the jacket, frame, and base plate together, and the outer periphery of the tie bolt and the inside of the tie bolt hole. In an internal combustion engine in which a low-viscosity viscous fluid such as lubricating oil is sealed in a tie bolt chamber formed between
In the vicinity of the part where the amplitude due to the resonance of the tie bolt is maximized, an enlarged diameter part having an outer diameter larger than other parts in a certain length range is provided, and the outer periphery of the tie bolt and the inner periphery of the tie bolt hole When the tie bolt resonates, the surface pressure of the viscous fluid in the small gap portion is increased when the tie bolt resonates so that the gap of the tie bolt is excessively small due to the resonance. A tie-bolt structure for an internal combustion engine, characterized in that the amplitude is reduced . The tie-bolt structure for an internal combustion engine according to claim 1, wherein the enlarged-diameter portion is configured by press-fitting an annular bush on the outer periphery of the tie bolt.

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