JP3226247B2 - Blower for connecting rod oil hole - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blowing device for an oil hole of a connecting rod (hereinafter, abbreviated as a connecting rod), and more particularly to a chip generated when boring an inner peripheral surface of a crankpin hole at a large end of the connecting rod. Is discharged to the outside without entering the oil hole by the fluid blow.

[0002]

2. Description of the Related Art Referring to FIG.
A conventional example of boring the inner peripheral surface of the crankpin hole at the large end will be described.

A connecting rod (1) is a rod-shaped member for connecting a crankshaft and a piston of an engine. The connecting rod (1) has a large end (2) on the crankshaft side and a small end (3) on the piston side. When boring the crankpin hole (6) at the large end (2) of the connecting rod (1), the large end (2) may have a large end due to the location of the cap connecting bolt detaching device and the like. Boring is performed with the part facing up.

An intermediate shaft portion (4) extending along the longitudinal axis of the connecting rod (1) has a lower portion of the inner peripheral surface of the crankpin hole (6) at the large end (2) and a small end (3). An oil hole (5) communicating with the upper part of the inner peripheral surface of the piston pin hole (7) is formed,
During operation of the engine, a sufficient amount of lubricating oil is distributed to the inner peripheral surface of the piston pin hole (7) at the small end (3). This oil hole (5) is always provided in a diesel engine, in particular, because a high compression ratio is adopted.

The connecting rod (1) is tapered (8) on both sides of the small end (3) for the purpose of reducing the weight, and then the inside of the crank pin hole (6) at the large end (2) is formed. Boring is performed on the peripheral surface, and then boring is performed on the inner peripheral surface of the piston pin hole (7) at the small end (3). The boring of the large end (2) and the small end (3) is performed by the tips (11) and (12) attached to the tips of dedicated rotary boring bars (9) and (10), respectively.

[0006] The main body of the connecting rod (1) is made of a metal material such as malleable cast steel or aluminum alloy, and is provided on the inner peripheral surface of a piston pin hole (7) at a small end portion (3) where a piston is to be attached. A bearing member (8) made of a soft metal, for example, a gunmetal or a babbitt metal, is fitted to alleviate an impact during engine operation. For this reason, as a tip (12) for cutting the inner peripheral surface of the piston pin hole (7) at the small end (3), a diamond tip having a high cutting ability for a soft metal is used, and a diamond tip having a higher hardness is used. As the tip (11) for cutting the inner peripheral surface of the crank pin hole (6) at the high large end (2), a tip made of sintered metal or tool steel is used.

As shown in FIG. 2, two boring bars (9) prepared for machining a large end (2) and a small end (3).
The movable support (1) is placed in parallel with and horizontal to (10).
Attach to the side of 3). The boring bar (9) for processing the large end (2) is mounted so as to have a longer projecting length than the boring bar (10) for processing the small end (3). The movable support (13) is horizontally moved in a direction approaching the connecting rod (1) (rightward in FIG. 2).
The inner peripheral surface of the crankpin hole (6) at the large end (2) is cut with the tip (11) attached to the tip of the boring bar (9). At this time, the processing reference pin (14A) of the fixed block (14) is fitted in the piston pin hole (7) of the small end (3), and the intermediate shaft portion (4) of the connecting rod (1) is fitted. Is gripped by the gripping arm (15) to fix the connecting rod (1) at a predetermined cutting position. Reference numeral (16) denotes a coolant that is injected toward the cut surface.

As the movable support (13) keeps moving horizontally to the right, cutting of the inner peripheral surface of the crank pin hole (6) at the large end (2) by the tip (11) is completed, Thereafter, cutting of the inner peripheral surface of the piston pin hole (7) at the small end (3) by the tip (12) attached to the tip of the boring bar (10) is started. The cutting reference pin (14A) of the fixed block (14) has a piston pin hole (7) before the cutting of the large end (2) by the tip (11) is completed and before the cutting by the tip (12) starts. ). At this time, in order to maintain the positioning accuracy of the connecting rod (1), particularly the small end portion (3), the intermediate shaft portion (4) of the connecting rod (1) is held in a state of being held by the holding arm (15). Then, the processing reference block (14B) is brought into contact with the rear surface of the small end (3).

In this state, the boring bar (10) further horizontally moves rightward together with the movable support (13). As the boring bar (10) rotates, the diamond tip (12) attached to the tip of the boring bar (10) cuts the inner peripheral surface of the piston pin hole (7) at the small end (3) to a predetermined inner diameter. When the tip (12) passes through the entire area of the piston pin hole (7) in the axial direction, boring of the small end portion (3) on the inner peripheral surface of the piston pin hole (7) is completed.

[0010]

When the inner peripheral surface of the crankpin hole (6) at the large end (2) is cut with the tip (11), chips (17) are generated. Most chips (17)
Is washed out by the coolant (16) and discharged to the outside through the open end of the crankpin hole (6), but some of the chips (17) are put into the oil hole (5) together with the coolant (16). Flow in. Since the cuttings (17) are curled or spring-shaped, they tend to bite into the hole surface in the oil hole (5), and there is a risk that the chips cannot be discharged even in the subsequent washing step. Since the presence or absence of the chips (17) cannot be detected, the connecting rod (1) may be incorporated into the engine with the chips (17) packed in the oil hole (5). In this case, when the engine is driven, supply of lubricating oil to the inner peripheral surface of the piston pin hole (7) at the small end (3) is hindered.

The chips (1) flowing out of the oil hole (5)
7) adheres to the small end bearing member made of a soft metal, thereby damaging the inner peripheral surface of the piston pin hole (7) at the small end (3). Specifically, a chip (1) is placed in the oil hole (5).
When the inner peripheral surface of the piston pin hole (7) of the small end portion (3) is cut with a diamond tip (12) with the 7) remaining as it is, the opening end of the oil hole (5) When the chips (17) sent out on the inner peripheral surface of the piston pin hole (7) bite into the small end side bearing member, the inner peripheral surface of the piston pin hole (7) may be damaged. In addition, problems such as loss of the diamond tip (12) occur.

Whether or not the diamond tip (12) has been lost is determined only at the stage when the machining accuracy of the inner peripheral surface of the piston pin hole (7) of the small end (3) of the connecting rod (1) is inspected in a subsequent process. Prove.

Until a defective portion is detected, in a boring process as a pre-process, the connecting rod (1) of the subsequent lot is subjected to cutting of the inner peripheral surface of the large end portion (2) and the small end portion (3). I have. As a result of repeating boring with the diamond chip (12) still missing, many defective connecting rods (1) are produced.

In order to avoid this problem, all the connecting rods (1) which have been subjected to the boring process have been damaged by cuttings (17) on the inner peripheral surface of the piston pin hole (7). It is necessary to inspect whether or not it is necessary, and the manufacturing cost is greatly increased as compared with the case where the sampling inspection method is adopted.

On the other hand, as means for preventing chips (17) from entering the oil hole (5), prior to cutting the large end (2), which is a source of the chips (17), the oil hole ( 5) There has been proposed a system in which a shaft-shaped clogging prevention member is inserted. However, in this scheme, the large end (2) and the small end (3)
It is necessary to remove the clogging prevention member from the oil hole (5) when the cutting of the inner peripheral surface of the hole is completed, which is inefficient.

Alternatively, the inner peripheral surfaces of the crank pin hole (6) and the piston pin hole (7) are cut with the small end (3) being upward and the large end (2) being downward. It is conceivable to prevent the chips (17) from entering the oil hole (5) by performing the above-mentioned method. However, when this supporting method is adopted, the cap of the large end (2) is attached to the body of the connecting rod (1). Arranging the bolt tightening device (nut runner) to be fixed to the portion below the connecting rod (1) is considerably difficult in terms of space and is not practical. Moreover, even if the crankpin hole (6) is bored with the large end (2) facing down, there is no guarantee that the intrusion of the cuttings (17) into the oil hole (5) can be completely prevented.

An object of the present invention is to prevent chips from boring a crankpin hole from entering the oil hole of a connecting rod.

[0018]

According to the present invention, there is provided an intermediate shaft portion connecting a small end portion and a large end portion with a piston pin hole at the small end portion and a crank pin hole at the large end portion. In the fixing block for positioning of the connecting rod formed with an oil hole communicating with

The reference pin of the fixed block fitted into the piston pin hole at the small end when the inner peripheral surface of the crank pin hole at the large end is cut is formed of titanium alloy on the outer peripheral surface.
A coating layer is formed by adhesion, and
A reference pin, to form a fluid passage communicating with the oil hole, the outer end of the fluid passage, and characterized by connecting a source of high pressure fluid
I do .

[0020]

[Function] From the start of cutting of the inner peripheral surface of the crank pin hole at the large end to the start of cutting of the inner peripheral surface of the piston pin hole at the small end, the fluid passage of the reference pin fitted into the piston pin hole at the small end. Then, the high-pressure fluid is injected into the oil hole of the connecting rod, whereby the chips generated by boring of the crankpin hole are discharged to the outside without entering the oil hole.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the following description, the same constituent members as those in FIG. 2 showing the related art are denoted by the same reference numerals in principle, and the description of the same items will be omitted.

The fixed block (14) provided as a positioning member on the small end side of the connecting rod (1) comprises a working reference block (14B) and a working reference pin (14C).

The machining reference pin (14C) has an oil hole (5)
A fluid passage (20) is formed in communication with the fluid passage, and a high-pressure air source (not shown) is connected to an upstream side of the fluid passage via an air supply pipe (22).

The outer diameter of the processing reference pin (14C) is adjusted to be slightly smaller than the inner diameter of the piston pin hole (7) at the small end (3). In order to prevent air leakage from between the inner peripheral surface of (7) and the outer peripheral surface of the processing reference pin (14C) and displacement due to wear, a processing reference that slides on the inner peripheral surface of the piston pin hole (7). A coating layer (21) of a titanium alloy is formed on the outer peripheral surface of the pin (14C).

When the inner peripheral surface of the crank pin hole (6) at the large end (2) is cut with the tip (11), the piston pin hole (7) at the small end (3) prior to the start of the cutting operation. The working reference pin (14C) is fitted therein, and compressed air supplied from a high-pressure air source is injected into the oil hole (5) through the fluid passage (20) as indicated by an arrow F. The blowing of the compressed air prevents the chip (17) from entering the oil hole (5) from the crank pin hole (6) at the large end (2), and the chip (17) is removed together with the coolant (16) by the crank. It is discharged outside through the open end of the pin hole (6).

When the cutting of the large end (2) by the tip (11) is completed, the working reference pin (14C) is extracted from the piston pin hole (7) of the small end (3),
The processing reference block (14B) is brought into contact with the rear surface of the small end (3). Thereafter, the diamond tip (12) attached to the tip of the small-end boring bar (10) is received in the piston pin hole (7), and is placed on the inner peripheral surface of the piston pin hole (7) at the small end (3). Perform cutting.

As the high-pressure fluid, high-pressure coolant can be used in addition to high-pressure air.

[0028]

According to the present invention , the crank pin hole at the large end is formed .
When cutting the peripheral surface, inside the piston pin hole at the small end
On the outer peripheral surface of the reference pin of the fixed block to be fitted to,
Since a titanium alloy coating layer was applied,
When the reference pin of the fixed block is fitted in the tonpin hole
Between the inner peripheral surface of the piston pin hole and the outer peripheral surface of the reference pin.
To prevent misalignment due to leakage and wear of high-pressure fluid.
Can be Also, the reference pin of the fixed block
A fluid passage communicating with the oil hole, and an outer end of the fluid passage;
The high pressure fluid source is connected to the
During ring processing, a stove is inserted into the piston pin hole of the connecting rod.
So that the oil hole of the pad communicates with the fluid passage of the reference pin.
Insert the pin and connect the connecting rod from the fluid passage of the reference pin.
A high-pressure fluid can be injected into the oil hole. And this
Injection of high pressure fluid into the crankpin bore
Chips generated by the ring enter the oil hole of the connecting rod
Without being discharged to the outside. This allows
The occurrence of defective connecting rods due to residual chips remaining in the oil holes of the connecting rods can be greatly reduced, and the inspection of all the connecting rods can be eliminated or simplified.

[Brief description of the drawings]

FIG. 1 is a front view of a connecting rod oil hole air blow device according to the present invention.

FIG. 2 is a front view showing a conventional example of a hole surface processing device for a large end of a connecting rod.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Connecting rod (Connecting rod) 2 Large end 3 Small end 4 Intermediate shaft part of connecting rod 5 Oil hole 6 Large end side hole 7 Small end side hole 9 Boring bar 10 Boring bar 11 Tip 12 Tip 14 Fixed block for positioning 14B Processing reference block 14C Processing reference pin 20 Fluid passage 21 Titanium alloy coating layer 22 Air supply pipe

Claims (1)

(57) [Claims] 1. A connecting rod positioning method in which an oil hole is formed in an intermediate shaft portion connecting a small end portion and a large end portion to communicate a piston pin hole of the small end portion and a crank pin hole of a large end portion. In the fixed block for use, the reference pin of the fixed block fitted in the piston pin hole of the small end when the inner peripheral surface of the crank pin hole of the large end is cut , a titanium alloy coating on the outer peripheral surface.
A layer is formed on the reference pin , and
A fluid passage communicating with the oil hole, and a high-pressure fluid source connected to an outer end of the fluid passage.