JP2002250446A - Sealing system of bolt-jointing part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealing system of bolt-jointing part, which has reduced number of parts and can protect fluid from leakaging along a bolt. SOLUTION: This sealing system of a bolt-jointing part, which is jointed with screwing a nut in a protruding bolt from a bolting hole of a jointed material, is constructed so that the bolt equips a stem of large diameter, a washer with passage hole is inserted through between the jointed material and the nut, and a chamfering surface is formed in the jointed material side of the passage hole of the screw, and an annular which surrounds a bolt is formed between the plane around the bolt hole opening of the jointed material, an O-ring is pressed into the annular so as to seal the gap between the O-ring and the plane around the bolt hole opening of the jointed material, thus this construction enables protects O-ring from breaking, simplification and reduction in number of parts and decrease of man-hours.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal for a bolt joint which prevents internal fluid from leaking from the bolt joint in a bolt fastening portion for fastening between an interior and a fluid containing a fluid such as a casing of an apparatus. Regarding the structure.

[0002]

2. Description of the Related Art In a bolt fastening portion which performs fastening through an inside and an outside containing a fluid such as a casing of a device,
There is a problem that the fluid leaks along the gap between the fastening hole and the fastening bolt.

As shown in FIG. 2, for example, a main bearing stand side bolt (hereinafter simply referred to as “bolt”) 01 of a main bearing stand of a diesel engine main body is fastened laterally to the main bearing stand. It is necessary to prevent the oil a from leaking along the bolt hole 2 and the bolt 01.

That is, when the nut 03 is screwed into the screw portion 01a at the tip of the bolt 01 inserted into the bolt hole 2 of the material 4 to be fastened, the nut 03 and the periphery of the bolt hole opening of the material 4 are fastened. The lubricating oil a may leak in the radial direction of the bolt from the surface 4a of the bolt (part A in the drawing) and in the axial direction of the bolt from the screw surface between the bolt 01 and the nut 03 (part B in the drawing). Was.

Therefore, conventionally, in order to prevent the leakage of the lubricating oil a from the portion A, an annular groove surrounding the bolt 01 is provided on a surface which is in contact with the surface 4a around the bolt hole opening of the nut 03, and the O-ring 05 is mounted. On the other hand, a cap 06 whose tip is closed in a bag shape is screw-fitted to the foremost end of the screw portion 01a of the bolt 01 protruding from the nut 03, and an annular groove surrounding the bolt 01 is formed on the cap-side surface of the nut 03. The O-ring 07 is attached, the cap 06 is brought into close contact with the nut 03, and the nut 0
The leakage of the lubricating oil a from the portion B was prevented by eliminating the leakage from between the cap 3 and the cap 06.

[0006]

However, in the conventional bolt joint sealing structure shown in FIG. 2, a special nut having an O-ring annular groove on both surfaces is used.
3 is required, and O-ring 0
5 is broken or O-ring 07 when cap 06 is attached
However, there is a problem in that a part not for direct fastening, such as a cap 06, is required in addition to the nut 03.

The present invention solves such a problem of the conventional sealing structure of a bolted joint, and provides a sealing structure of a bolted joint which can prevent a fluid from leaking through a bolt only by fastening parts. The task is to do so.

[0008]

Means for Solving the Problems (1) The present invention has been made to solve the above-mentioned problems, and as a means, a screw at a tip end portion of a bolt protruding from a bolt hole of a material to be fastened. In a seal structure of a bolted joint portion in which a nut is screwed and fastened to a portion, the bolt has a large-diameter stem portion having a diameter slightly smaller than the diameter of the bolt hole before and after the opening of the bolt hole. A washer having a through-hole having a diameter slightly larger than the large-diameter stem portion is inserted between the material and the nut, and the corner of the end of the through-hole of the washer on the side of the material to be fastened has a chamfered surface. When the nut is fastened, an annular gap surrounding the bolt is formed between the surface around the opening of the bolt hole of the workpiece, the peripheral surface of the large-diameter stem portion, and the chamfered surface. And an O-ring is pressed into the annular space. A bolt, wherein a seal is provided between the O-ring and a surface around an opening of a bolt hole of the workpiece, and a seal is provided between the O-ring and a peripheral surface of the large-diameter stem portion. A joint seal structure is provided.

With the construction of the above means, the O-ring is prevented from being broken by merely being pressed by the washer, and the nut does not need to be provided with an annular groove for the O-ring. Therefore, in the fastening step, sealing in two directions, the bolt radial direction and the bolt axial direction, is performed simultaneously at the time of fastening the nut.

(2) As a second means, in the sealing structure of the bolt joint portion of the first means, the bolt is a main bearing stand side bolt of a main bearing stand of a diesel engine. Provide a sealing structure of the part.

According to the second means, in addition to the operation of the first means, especially in the case of a diesel engine, the main bearing stand side bolts of the main bearing stand need to be bolted laterally at the lower part of the engine, which requires structural strength. , But in such a case, the sealing is facilitated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A seal structure for a bolt joint according to an embodiment of the present invention will be described with reference to FIG.
FIG. 1A is a sectional view of a bolt fastening part showing a main part of the present embodiment, and FIG. 1B is an enlarged explanatory view of a C part in FIG.

In this embodiment, as shown in FIG. 1, the bolt 1 protruding from the bolt hole 2 of the workpiece 4 is
A large-diameter stem portion 1b having a smooth peripheral surface having a diameter slightly smaller than the diameter of the bolt hole 2 is provided in a portion of the workpiece 4 located before and after the opening of the bolt hole 2, and the large-diameter stem portion 1 is provided.
A threaded portion 1a is provided on the tip side from b.

A washer 8 having a through-hole 8a having an inner diameter slightly larger than the outer diameter of the large-diameter stem portion 1b is inserted around the large-diameter stem portion 1b, and the nut 3 screwed into the screw portion 1a secures the washer 8. The material 4 to be fastened is sandwiched therebetween. The surface 4a around the opening of the bolt hole of the work 4 is smooth-finished.

The washer 8 has a chamfered surface 8b formed by chamfering the end of the through hole 8a on the workpiece 4 side at an angle of about 45 °. An annular space 9 surrounding the bolt 1 having an isosceles triangular cross section surrounded by the peripheral surface of the diameter stem portion 1b, the chamfered surface 8b of the washer 8, and the surface 4a around the opening of the bolt hole of the workpiece 4 is formed.

Therefore, in the bolt fastening, an O having an appropriate cross-sectional dimension that matches the size of the cross-section of the cavity 9 in advance.
The ring 10 is attached to the annular gap 9 and then bolted.

Then, as shown in FIG. 1 (b), before the normal fastening, the O-ring 10 having a circular cross section is deformed and pushed into the gap 9 having an isosceles triangular cross section. At the surface 4a and the point D around the bolt hole opening, the large-diameter stem 1
At the same time, it is pressed against the peripheral surface of b at point E.

At the same time, the pressure between the O-ring 10 and the surface 4a around the opening of the bolt hole of the work 4 is sealed by the pressure contact at the point D, and the bolt in the bolt radial direction passing between the work 4 and the washer 8 is sealed. Of the lubricating oil a is prevented, and the O-ring 10 and the peripheral surface of the large-diameter stem portion 1b are sealed by the pressure contact at the point E, so that the peripheral surface of the large-diameter stem portion 1b of the bolt 1 and the through hole of the washer 3 are formed. 8a lubricating oil a in the axial direction of the bolt passing between
Is prevented from leaking.

As described above, according to the seal structure of the bolt joint portion of the present embodiment, the O-ring 10 is only pressed by the washer 3 and does not receive the shearing force around the bolt axis. In addition to this, it is not necessary to provide an annular groove for the O-ring in the nut 3 and a normal nut can be used, so that a cap for preventing leakage of lubricating oil is not required, and parts can be simplified and reduced. In the fastening step, sealing in two directions of the bolt radial direction and the bolt axial direction is simultaneously performed at the time of fastening the nut, so that the O-ring mounting tightening is reduced from two steps to one step, and the number of steps can be reduced.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications may be made to the specific structure within the scope of the present invention. Needless to say.

For example, in the above-mentioned conventional examples and the embodiments, the main bearing stand side bolts of the main bearing stand of the diesel engine main body have been described as examples. However, the sealing structure of the bolt joints in the body, casing, etc., which contains a fluid inside. It can be widely applied to

Of course, especially in a diesel engine, the main bearing stand side bolts of the main bearing stand must be bolted laterally at the lower part of the engine, which requires structural strength. This solves the problem that could not be found, and facilitates sealing of the main bearing stand side bolt, and its effect contributes to improvement of the diesel engine.

[0023]

(1) According to the first aspect of the invention, the sealing structure of the bolted joint is fastened by screwing a nut to a threaded portion at the tip end of the bolt protruding from the bolt hole of the workpiece. In the sealing structure of a bolt joint, the bolt includes a large-diameter stem portion having a diameter slightly smaller than the diameter of the bolt hole before and after the opening of the bolt hole, and the large-diameter stem is provided between the workpiece and the nut. A washer having a through hole with a diameter slightly larger than the diameter stem portion is inserted, and the corner of the end of the through hole of the washer on the side of the workpiece is chamfered, and the nut is fastened, An annular space surrounding the bolt is formed between the surface around the opening of the bolt hole of the material to be fastened, the peripheral surface of the large-diameter stem portion, and the chamfered surface,
An O-ring is press-fitted in the annular space to seal between the O-ring and the surface around the opening of the bolt hole of the material to be fastened, and between the O-ring and the peripheral surface of the large-diameter stem portion. Is sealed so that the O-ring is only held down by the washer to prevent breakage as in the prior art, and there is no need to provide an annular groove for the O-ring in the nut, and the lubricating oil leaks out. No cap is required to prevent this, parts can be simplified and reduced, and the tightening process can also be performed in two directions, the bolt radial direction and the bolt axial direction, at the same time when the nut is fastened, reducing man-hours. Becomes

(2) According to the invention of claim 2, claim 1
In the seal structure described in (1), the bolt is configured to be a main bearing stand side bolt of a main bearing stand of a diesel engine. Therefore, in addition to the effect of the invention of the above-mentioned claim 1, especially in a diesel engine, the main bearing stand is used. In the main bearing stand side bolts, bolts requiring structural strength must be tightened laterally at the lower part of the engine, and the problem that no other preferable sealing structure for bolt fastening parts could be found was solved. This facilitates the sealing of the diesel engine and contributes to the improvement of the diesel engine.

[Brief description of the drawings]

1A and 1B are explanatory views of a sealing structure of a bolt fastening portion according to an embodiment of the present invention, wherein FIG. 1A is a cross-sectional view of a bolt fastening portion showing a main part of the embodiment, and FIG. a) It is a middle C part enlarged explanatory view.

FIG. 2 is an explanatory view of a conventional sealing structure of a bolt fastening portion, and is a cross-sectional view of a bolt fastening portion showing a main part thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bolt 1a Screw part 1b Large diameter stem part 2 Bolt hole 3 Nut 4 Workpiece 4a Surface around bolt hole opening 8 Washer 8a Chamfer surface 9 Void 10 O-ring

Claims (2)

[Claims] In a seal structure of a bolt joint for fastening a nut to a threaded portion of a bolt protruding from a bolt hole of a material to be fastened by fastening a nut to the bolt, the bolt extends around the opening of the bolt hole. A washer having a large diameter stem having a diameter slightly smaller than the diameter of the bolt hole, and a washer having a through hole with a diameter slightly larger than the large diameter stem is inserted between the fastening member and the nut. The corner of the end of the through-hole on the side of the material to be fastened has a chamfered surface, and in a state where the nut is fastened, a surface around the opening of the bolt hole of the material to be fastened,
An annular space surrounding the bolt is formed between the peripheral surface of the large-diameter stem portion and the chamfered surface, and an O-ring is press-fitted in the annular space, and the O-ring and the bolt of the material to be fastened are formed. A sealing structure for a bolt joint, wherein a seal is formed between a surface around an opening of the hole and a seal between the O-ring and a peripheral surface of the large-diameter stem portion. 2. The seal structure for a bolt joint according to claim 1, wherein the bolt is a main bearing stand side bolt of a main bearing stand of a diesel engine.