JP-2026076111-A - Preloaded bolt assembly

JP2026076111AJP 2026076111 AJP2026076111 AJP 2026076111AJP-2026076111-A

Abstract

[Problem] A preload bolt assembly for connecting at least two engine components of a large turbocharged two-stroke uniflow crosshead internal combustion engine is disclosed. [Solution] A preload bolt assembly for connecting at least two engine components (22, 23) of a large turbocharged two-stroke uniflow crosshead internal combustion engine comprises a tie rod (40) and a nut (42), the two engine components being connected by the tie rod and nut, one end of the tie rod passing through a mounting hole (41) of the engine component and the nut being screwed into the threads of the end. This preload bolt assembly is characterized by comprising a braking means disposed on the outer circumference of the tie rod to prevent the tie rod from moving through the mounting hole in the event of failure of the tie rod. [Selection Diagram] Figure 4

Inventors

ハンセンヴィゴアンダース
アドリアンセンクリスチャン

Assignees

エヴァレンス，フィリアル・アフ・エヴァレンス・エスイー，ティスクランド

Dates

Publication Date: 20260511
Application Date: 20250903
Priority Date: 20241023

Claims (16)

A preload bolt assembly for connecting at least two engine components of a large turbocharged two-stroke uniflow crosshead internal combustion engine, The preload bolt assembly comprises at least one tie rod having threads at its end and at least one nut for securing one of the at least two engine components to the other of the at least two engine components. The at least two engine components are connected by the at least one tie rod and the at least one nut, and each of the at least one tie rod has at least one end passing through a mounting hole in at least one of the at least two engine components. The at least one nut is screwed into the threads of the at least one tie rod at one end of the mounting hole. The preload bolt assembly is characterized by comprising a braking means disposed on the outer circumference of at least one of the at least one tie rods, and in the event of failure of the tie rod equipped with the braking means, the tie rod is prevented from moving through the mounting hole. Preloaded bolt assembly.
Each of the braking means is positioned on the opposite side of the mounting hole from the nut and has a radial dimension larger than the mounting hole, according to claim 1, the preload bolt assembly.
The preload bolt assembly according to claim 1, wherein the braking means is provided in the form of a bushing.
The preload bolt assembly according to claim 3, wherein the bushing is formed to have a conical outer surface at least at the end facing the mounting hole, the diameter of the conical outer surface being smallest at the end facing the mounting hole, and the smallest diameter of the conical outer surface being smaller than the diameter of the mounting hole.
The preload bolt assembly according to claim 4, wherein at least a portion of the bushing has a plurality of longitudinally extending slits at the end having the conical outer surface, and the end having the conical outer surface is divided into a plurality of segments, and when the tie rod through which the bushing passes breaks and the bushing is pushed into the mounting hole of the engine component, the plurality of segments can be crushed radially toward the tie rod.
The preload bolt assembly according to claim 3, wherein the bushing is held in a predetermined position by a hose clamp, and the hose clamp is attached to the tie rod immediately below the bushing to support the bushing.
The preload bolt assembly according to claim 1, wherein the braking means is disposed within the mounting hole.
The preload bolt assembly according to claim 7, wherein the braking means is provided in the form of a sleeve.
The preload bolt assembly according to claim 8, wherein the sleeve comprises an annular collar at the end facing the nut, having a lower side that contacts the engine component and an upper side that faces the nut.
The preload bolt assembly according to claim 8, wherein a washer is disposed between the nut and the sleeve.
The preload bolt assembly according to claim 8, wherein two tie rods are mounted adjacent to each other in their respective mounting holes, a common double washer is used for the two tie rods, and the double washer is positioned between the nut and the sleeve of each of the two tie rods.
The preload bolt assembly according to claim 8, wherein the tie rod has a diameter greater than the inner diameter of the sleeve positioned in the mounting hole, on the opposite side of the mounting hole relative to the nut.
The preload bolt assembly according to claim 12, wherein the tie rod has a first portion having a first diameter that passes through the mounting hole, a second portion having a larger diameter than the first portion, and a conical portion between the first portion and the second portion.
The preload bolt assembly according to claim 8, wherein the sleeve is provided with a plurality of longitudinal slits in at least a portion of the end opposite to the end facing the nut, thereby dividing the opposite end into a corresponding number of segments.
The preload bolt assembly according to claim 7, wherein a conical portion is provided in the mounting hole at the end opposite to the end facing the nut.
A large turbocharged two-stroke uniflow crosshead internal combustion engine comprising a preload bolt assembly as described in any one of claims 1 to 15.

Description

The present invention relates to a preload bolt assembly for connecting at least two engine components of a large turbocharged two-stroke uniflow crosshead internal combustion engine. However, the engine comprises at least one cylinder in a cylinder liner, a reciprocating piston in the cylinder liner, a cylinder cover covering the cylinder, a combustion chamber formed between the reciprocating piston and the cylinder cover within the cylinder liner, a cylinder block, a machine frame, and a bed frame. The at least two engine components are connected by a plurality of tie rods having threads at their ends, and each of the plurality of tie rods has at least one end passing through a mounting hole in at least one of the at least two engine components. A nut for securing one of the at least two engine components to the other of the at least two engine components is screwed into the threads at one end of the mounting hole. Background of the Invention Large turbocharged two-stroke uniflow crosshead internal combustion engines are typically used as prime movers in large ocean-going vessels such as container ships and power plants. This type of engine very often runs on heavy fuel oil or diesel fuel. In the large two-stroke engines of the type described above, various engine components are secured together by tie rods. During combustion in the cylinder, a downward force acts on the piston. However, an equivalent upward force acts on the cylinder cover, which is transmitted to the cylinder block, engine frame, and bed plate. In the conventional large two-stroke engines of the type described above, the cylinder cover is typically secured to the cylinder block by a set of six to eight tie rods. One end of each tie rod is threaded and screwed into the corresponding threaded hole in the cylinder block. The other end passes through a hole in the cylinder cover and is secured by a nut screwed into the threads of the tie rod. This secures the cylinder liner in place. Another set of tie rods extends from the underside of the bed plate to the topside of the cylinder block, securing the engine block, engine frame, and bed plate together. The latter tie rods may pass through tubes welded to the frame. Reinforcements may also be provided at specific locations along these tubes to prevent fatigue failure due to lateral vibrations. In particular, to absorb the large forces acting on the cylinder cover, cylinder block, and bed plate during the cylinder's combustion period, all tie rods are typically pre-loaded with a tensile force of approximately 1 ton or more during engine assembly. Therefore, tie rods possess internal forces as tensile stress. Consequently, if a tie rod breaks for any reason, it could fly upwards, enter the engine compartment, and cause serious damage to personnel inside or the engine itself. Causes of fracture include not only normal excessive load from the engine itself, but also poor maintenance due to rust, impact marks, material defects, ship vibrations, and manufacturing defects (especially faulty threading). The present invention also relates to a large turbocharged two-stroke uniflow crosshead internal combustion engine comprising a preload bolt assembly described above and in the appended claims. The object of the present invention is to provide a preload bolt assembly of the type described above, which at least significantly reduces the aforementioned problems related to tie rod breakage, for connecting at least two engine components of a large turbocharged two-stroke uniflow crosshead internal combustion engine. The aforementioned and other issues are resolved by the features described in the independent claims. More specific implementations will become apparent from the dependent claims, specification, and drawings. According to the first aspect, a preload bolt assembly for connecting at least two engine components of a large turbocharged two-stroke uniflow crosshead internal combustion engine, The preload bolt assembly comprises at least one tie rod having threads at its end and at least one nut for securing one of the at least two engine components to the other of the at least two engine components. The at least two engine components are connected by the at least one tie rod and the at least one nut, and each of the at least one tie rod has at least one end passing through a mounting hole in at least one of the at least two engine components. The at least one nut is screwed into the threads of the at least one tie rod at one end of the mounting hole. The preload bolt assembly is characterized by comprising a braking means disposed on the outer circumference of at least one of the at least one tie rods, thereby preventing the tie rod from moving through the mounting hole in the event of failure of the tie rod equipped with the braking means. Therefore, even if the tie rod breaks, it is prevented from flying upward through the mounting hole in the engine component and into the engine room. In princip