JPH07293546A - Connecting rod bolt - Google Patents

Abstract

PURPOSE:To provide a connecting rod bolt which can improve the durability by dispersing the stress. CONSTITUTION:A connecting rod bolt 1 to fasten the bearing cap 11 of a demountable connecting rod to a connecting rod main body 12 is made in a structure having a flange 2 at one end, and forming screws 3 and 4 at the part neighboring the flange 2 and at the other end. And the imperfect screw part of the screw 3 of the connecting rod bolt 1 is cut off by an R-shaped groove 3a. Since the axial tension (tensile force) operating to the connecting rod bolt 1 is received by the flange 2 and other two screws 3 and 4, and by two positions of the flange 2 and the screw 3 at the connecting rod main body 12 side, the stress generated to the connecting rod bolt 1 can be dispersed to the flange 2 and the screw 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connecting rod bolt for fastening a bearing cap of an assembled connecting rod of an internal combustion engine to a connecting rod body.

[0002]

2. Description of the Related Art A prefabricated connecting rod, which is adopted in many multi-cylinder internal combustion engines, has its large end assembled to a crankshaft by fastening a bearing cap to a connecting rod body with a connecting rod bolt.

Here, a conventional connecting rod bolt and a tightening structure for an assembling connecting rod using the connecting rod bolt will be described with reference to FIGS. 4 to 7.

That is, FIGS. 4 to 7 are sectional views of the tightening portion of the assembly type connecting rod, and the connecting rod bolt 101 used in the tightening structure shown in FIG. 4 has a flange portion 1 at one end thereof.
02, the reamer part 107 in the middle part, and the screw part 1 in the other end part.
So-called reamer bolts each having 03,
This is the connecting rod body 112 and the bearing cap 11.
The bolt holes 113 and 114, which are respectively formed in the No. 1, are passed through from below with the threaded portion 103 facing upward. Then, the bearing cap 111 is assembled to the connecting rod body 112 by tightening the nut 106 that is screwed into the threaded portion 103 protruding from the connecting rod body 112 of the connecting rod bolt 101.

The connecting rod bolt 201 used in the tightening structure shown in FIG. 5 has a hexagonal column-shaped head portion 208 at one end and a threaded portion 203 at the other end, which is the connecting rod body 212. The screw portion 203 is passed through the bolt holes 213 and 214 penetrating the bearing cap 211 from below and the screw head 203 is turned by a tool (not shown), so that the screw portion 203 is connected to the connecting rod body. Screw portion 213a of the bolt hole 213 on the 212 side
The bearing cap 211 is assembled to the connecting rod body 212.

Further, the connecting rod bolt 301 used in the tightening structure shown in FIG. 6 is a so-called stud bolt,
Threaded portions 303 and 304 are formed at both ends thereof, and the reamer portion 3 is provided in a portion adjacent to one of the screw portions 303.
07 are formed. The connecting rod bolt 301 is pre-planted in the connecting rod body 312 by screwing the screw portion 303 into the screw portion 313a of the bolt hole 313 on the connecting rod body 312 side. A bolt hole 314 penetrating the bearing cap 311 is passed through a portion protruding downward from the connecting rod 311 to connect the connecting rod bolt 301.
The bearing cap 311 is assembled to the connecting rod body 312 by screwing the nut 306 into the screw portion 304 protruding downward from the bearing cap 311 and tightening the nut 306.

In the tightening structure shown in FIG. 7, the connecting rod bolt 101 shown in FIG. 4 is turned upside down and tightened, and the other structure is the same as that shown in FIG.

[0008]

However, in the connecting rod bolt 101 shown in FIGS. 4 and 7, the axial force (pulling force) acting on the connecting rod bolt 101 is received by the flange portion 102 and the screw portion 103, so that it is particularly preferable. Flange part 102
Concentrated load acts on the connecting rod bolt 101, and the stress in this portion may become excessive, leading to a decrease in durability of the connecting rod bolt 101.

Similarly, the connecting rod bolt 20 shown in FIG.
In the connecting rod bolt 301 shown in FIG. 1 and FIG. 6, the axial force (tensile force) acting on each of them is received by the head portion 208, the screw portion 203, and the screw portions 303 and 304, so that these portions are excessive. There is a possibility that various stresses may act and the same problem as described above may occur.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a connecting rod bolt which can improve durability by distributing stress.

[0011]

[Means for Solving the Problems] In order to achieve the above object,
According to the invention of claim 1, a connecting rod bolt for tightening the bearing cap of the assembly type connecting rod to the connecting rod body has a flange portion at one end, and a screw portion is formed at a portion adjacent to the flange portion and the other end portion. It is characterized by having been made.

The invention according to claim 2 is the above-mentioned claim 1.
In the invention described above, the incomplete screw portion on the root side of the flange portion of the screw portion formed in the portion adjacent to the flange portion is removed.

[0013]

According to the first aspect of the present invention, the connecting rod bolt is inserted and screwed into the bolt hole penetrating the connecting rod body and the bearing cap from the other end screw portion side, and the flange portion of the connecting rod bolt is connected. The bearing cap is fastened to the connecting rod body by screwing a nut onto a portion of the other end threaded portion protruding outside the bearing cap and tightening the nut.

Therefore, the axial force (tensile force) acting on the connecting rod bolt is received by the two screw portions in addition to the flange portion, and the axial force is received by the flange portion and the screw portion on the connecting rod body side. The stress generated in the connecting rod bolts is dispersed in the flange portion and the screw portion, which enhances the durability of the connecting rod bolts.

Further, according to the second aspect of the present invention, since the incomplete screw portion on the root side of the flange portion of the screw portion formed in the portion adjacent to the flange portion is cut off, the flange portion functions as a stopper. As described above, the stress generated in the connecting rod bolt is surely dispersed in the flange portion and the screw portion.

[0016]

An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing a connecting rod tightening structure using a connecting rod bolt according to the present invention. FIG. 2 is a sectional view for explaining a tightening procedure of the connecting rod bolt.
[Fig. 3] is a half cross-sectional view of the assembly type connecting rod.

The assembly type connecting rod 10 shown in FIG. 3 is constructed by fastening a divided half-ring shaped bearing cap 11 to a connecting rod body 12 with a connecting rod bolt 1 according to the present invention, and a small end 10a thereof is inserted into this. Is also connected to a piston (not shown) via a piston pin (not shown), and the large end 10b is assembled to a crankshaft (not shown).

Here, the connecting rod bolt 1 according to the present invention.
Details of the configuration will be described with reference to FIG.

The connecting rod bolt 1 has a flange portion 2 having an elliptical shape in plan view at one end (an upper end in the illustrated example), and a screw portion 3 is formed in a portion adjacent to the flange portion 2, and the like. The threaded portion 3 is provided at the end (the lower end in the illustrated example).
And a threaded portion 4 having the same diameter as that of. The portion of the connecting rod bolt 1 between the screw portions 3 and 4 constitutes a straight portion 5 having a smaller diameter than the screw portions 3 and 4.

Further, in the connecting rod bolt 1 according to the present embodiment, the incomplete threaded portion existing at the root of the threaded portion 3 formed adjacent to the flanged portion 2 side on the flanged portion 2 side is cut off. An R-shaped groove 3a is formed in the.

To tighten the bearing cap 11 to the connecting rod body 12 using the connecting rod bolt 1, first, as shown in FIG. Connect the connecting rod bolt 1 to the threaded portion 13a of the bolt hole 13
Screw in the screw part 4.

After that, when the connecting rod bolt 1 is continuously rotated, the threaded portion 4 of the connecting rod bolt 1 passes through the threaded portion 13a of the bolt hole 13, and the threaded portion 13a of the bolt hole 13 has the other threaded portion of the connecting rod bolt 1. When 3 is screwed and the flange portion 2 of the connecting rod bolt 1 comes into contact with the connecting rod body 12 as shown in FIG. 1, the screwing of the connecting rod bolt 1 is completed. At this time, the threaded portion 4 of the connecting rod bolt 1 protrudes below the bearing cap 11 through the straight bolt hole 14 penetrating the bearing cap 11.

Next, the nut 6 is screwed onto the threaded portion 4 of the connecting rod bolt 1 projecting downward from the bearing cap 11, and the nut 6 is turned and tightened to the threaded portion 4. It is fastened to the main body 12 and thereby the connecting rod 1
The large end portion 0b of 0 is assembled to the crankshaft (not shown) as described above.

The axial force (tensile force) acting on the connecting rod bolt 1 is two screw parts 3 and 4 in addition to the flange part 2.
Since the axial force is received by the flange portion 2 and the screw portion 3 on the connecting rod body 12 side, the stress generated in the connecting rod bolt 1 is
And the screw parts 3 are dispersed, and as a result, the connecting rod bolt 1
Durability is improved.

Further, according to this embodiment, the R-shaped groove 3a is formed at the root of the flange portion 2 of the connecting rod bolt 1,
Since the incomplete screw portion of the screw portion 3 is cut off by the R-shaped groove 3a, the flange portion 2 functions as a stopper, and the stress generated in the connecting rod bolt 1 is ensured in the flange portion 2 and the screw portion 3 as described above. Dispersed in.

In this embodiment, since the screw portions 3 and 4 of the connecting rod bolt 1 have the same diameter, the screw portion 4 is tightened when the connecting rod bolt 1 is tightened.
While it is necessary to screw the threaded portion 13a of the bolt hole 13 on the side to pass the threaded portion 13a, the diameter of the material is small and the weight of the connecting rod bolt 1 itself can be reduced. On the other hand, if the threaded portion 3 of the connecting rod bolt 1 and the threaded portion 13a of the bolt hole 13 on the connecting rod body 12 side have a larger diameter than the threaded portion 4, the threaded portion 4 is tightened when the connecting rod bolt 1 is tightened. It is not necessary to screw the threaded portion 13a of the screw 13 into the threaded portion 13a, and the threaded portion 4 can be easily inserted into the threaded portion 13 of the bolt hole 3, so that the mass productivity of the engine can be improved. Benefits are obtained.

[0028]

As is apparent from the above description, according to the invention of claim 1, the axial force (tensile force) acting on the connecting rod bolt is received by the two screw portions in addition to the flange portion, and the connecting rod main body is obtained. On the side, since the axial force is received at the flange portion and the screw portion, the stress generated in the connecting rod bolt is dispersed in the flange portion and the screw portion, and the effect of improving the durability of the connecting rod bolt is obtained.

According to the second aspect of the invention, since the incomplete threaded portion on the root side of the flange portion of the threaded portion formed adjacent to the flange portion of the connecting rod bolt is cut off, the flange portion is a stopper. As a result, the stress generated in the connecting rod bolt is reliably dispersed in the flange portion and the screw portion as described above.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a tightening structure of an assembly type connecting rod using a connecting rod bolt according to the present invention.

FIG. 2 is a cross-sectional view illustrating a procedure for tightening a connecting rod bolt according to the present invention.

FIG. 3 is a half cross-sectional view of the assembly type connecting rod.

FIG. 4 is a sectional view showing a tightening structure of a conventional connecting rod using a connecting rod bolt in the related art.

FIG. 5 is a sectional view showing a tightening structure of a conventional connecting rod using a connecting rod bolt in the related art.

FIG. 6 is a cross-sectional view showing a conventional tightening structure for a connecting rod using connecting rod bolts.

FIG. 7 is a cross-sectional view showing a conventional tightening structure for an assembly type connecting rod using connecting rod bolts.

[Explanation of symbols]

 1 connecting rod bolt 2 flange part 3,4 screw part 3a R-shaped groove (incomplete screw part) 6 nut 10 assembly type connecting rod 11 bearing cap 12 connecting rod body

Claims (2)

[Claims] 1. A bolt for tightening a bearing cap of a preassembled connecting rod to a connecting rod body, comprising a flange portion at one end, and a screw portion formed at a portion adjacent to the flange portion and at the other end. A characteristic connecting rod bolt. 2. The connecting rod bolt according to claim 1, wherein an incomplete threaded portion on a root side of the flange portion of a threaded portion formed in a portion adjacent to the flange portion is cut off.