JPH0771438A - Shaft holding member and manufacturing method thereof - Google Patents

Abstract

(57) [Summary] [Objective] To provide a connecting rod made of an Al alloy that achieves a longer life. [Constitution] The connecting rod C is a rod member 3 having mating surfaces 8 and 10 at both ends in the circumferential direction of semicircular recesses 7 and 9, respectively.
And a cap 6 for matching the opposing mating surfaces 8, 10 and for opposing the semi-circular recesses 7,
9 with the crankpin hole 11 formed, the bolt 4
It is concluded by. The rod member 3 and the cap 6 are
A forged product that is made of an Al alloy and is simultaneously forged in a connecting rod-shaped cavity, and the opposing mating surfaces 8 and 10 are formed by the flow of material during forging and are in a fitting relationship with each other. Countless concave and convex parts a ₁ , a ₂ , b
₁ and b ₂ . As a result, it is possible to prevent a position shift between the mating surfaces 8 and 10 in a direction parallel to the mating surfaces 8 and 10, and to avoid a situation in which only the rod member 3 receives stress.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a shaft holding member, and in particular, first and second halves each having a mating surface at both circumferential ends of a semi-circular recess, the first and second halves comprising: The present invention relates to a shaft holding member that is fastened by a plurality of screw members in a state in which both mating surfaces facing each other are matched and a shaft insertion hole is formed by both semicircular recesses, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A shaft holding member having the above construction is a rod member in which a first half body has a small end portion at one end and a semi-annular portion for a large end portion at the other end, and a second half body. There is known a connecting rod for an internal combustion engine, which is a semi-annular cap that is fastened to the semi-annular portion with a screw member, for example, a bolt, and forms a large end portion in cooperation with the semi-annular portion.

Conventionally, connecting rods for internal combustion engines have generally been made of carbon steel for machine structures (see, for example, "Encyclopedia of automobiles", published by Asakura Shoten in 1978).

In recent years, as one measure against environmental problems, there has been a demand for low fuel consumption in internal combustion engines for automobiles, and in order to meet the demand, it is effective to reduce the weight of component parts, especially moving parts. In this case, among the moving parts, the lightening of the connecting rod has a great effect on reducing fuel consumption. Therefore, it is desired to develop a lightweight and inexpensive connecting rod instead of the conventional steel connecting rod.

[0005]

Therefore, in order to reduce the weight and the cost, the connecting rod is made of a light alloy A.
It is conceivable that it is made of a 1-alloy.

However, the Al alloy connecting rod is
Due to the fact that the rigidity of the alloy is essentially lower than that of steel, elastic deformation occurs under relatively low stress, so that it is parallel to the mating surface between the rod member and the cap. Positional deviation in the direction is likely to occur, and as a result, a situation occurs in which stress is applied only to the rod member, and the life of the rod member is significantly impaired.

In order to solve the above-mentioned problems, it is effective to increase the axial force of the bolt, but if such a means is adopted, the Al alloy has low rigidity and the creep strength is lower than that of steel. This causes new problems such as the depression of the bolt head seat surface.

In view of the above, the present invention adopts a relatively simple means to surely prevent the positional deviation between the mating surfaces of the light alloy first and second halves. An object is to provide a holding member.

Further, according to the present invention, the shaft holding member is inexpensive,
Moreover, it is an object of the present invention to provide the above-mentioned manufacturing method, which enables efficient manufacturing.

[0010]

DISCLOSURE OF THE INVENTION The present invention provides first and second semi-circular recesses each having a mating surface at both ends in the circumferential direction.
The first and second halves are provided with halves, and the first and second halves have their mating surfaces facing each other aligned with each other, and are fastened by a plurality of screw members in a state in which a shaft insertion hole is formed by both semicircular recesses. In the member, the first and second halves are forged products that are made of a light alloy and are simultaneously forged in a shaft-holding member-shaped cavity, and the opposing mating surfaces are It is characterized by having innumerable concaves and convexes which are formed by the flow of material and have a fitting relationship with each other.

The present invention comprises first and second halves having mating surfaces at both circumferential ends of the semi-circular recess, the first and second halves having opposite mating surfaces thereof. In manufacturing a shaft holding member which is fitted with and is fastened by a plurality of screw members in a state where the shaft insertion hole is formed by both semicircular recesses, the shaft holding member has a shape similar to that of the first and second halves. The steps of obtaining the first and second preforms made of a light alloy, the step of heating both preforms, the both preforms in the cavity of the mold in the shape of the shaft holding member, and the mating surfaces of the preforms. A step of installing corresponding surfaces to face each other, and simultaneously forging the first and second preforms,
Obtaining the first and second halves having innumerable recesses and protrusions, which are formed by the flow of material during forging and have a fitting relationship with each other, on the opposing surfaces facing each other; And a step of fitting the concave portion and the convex portion of the mating surfaces when the second half body is fastened with the screw member.

[0012]

In the shaft holding member, since the first and second halves are forged products made of light alloy, they are lightweight and have high strength. Further, the positional deviation between the mating surfaces of the first and second halves facing each other in the direction parallel to the mating surfaces is surely prevented by the innumerable recesses and projections fitted to each other.

In this case, since the concaves and convexes are formed by the flow of the material, they are extremely irregularly arranged, and they are minute ones that cannot be obtained by machining. It is possible to reliably disperse the stress generated between them and improve the durability of the concavo-convex fitting structure on the mating surfaces.

On the other hand, according to the above-mentioned manufacturing method, since the mating surfaces of the first and second halves are not required to be machined, the number of manufacturing steps and the manufacturing cost can be reduced accordingly, and the first Also, unlike the case where the connecting rod material in which the second halves are integrated is subjected to a cutting process to be divided into two, waste of the material due to the provision of the cutting allowance is not caused, and at the same time, the number of manufacturing steps can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a connecting rod C for an internal combustion engine as a shaft holding member is made of an aluminum alloy which is a light alloy, and has a small end portion 1 at one end and a semi-annular portion for a large end portion at the other end. Al alloy rod members 3 as first halves each having 2 and a plurality of, in the illustrated example, two steel bolts 4 as screw members on the semi-annular portion 2, and the semi-annular portion 2 A as the second half forming the large end 5 by the cooperation of
It is composed of a semi-annular cap 6 made of an alloy.

The semi-annular portion 2 of the rod member 3 is a semi-circular recess 7
Of the semicircular recess 9 has mating surfaces 8 at both ends in the circumferential direction, and the cap 6 also has mating surfaces 10 at both ends in the circumferential direction of the semicircular recess 9. The semi-annular portion 2 and the cap 6 have two mating surfaces 8 and 10 facing each other, and the two semi-circular recesses 7 and 9 are provided with a crank pin hole 11 as a shaft insertion hole. It is fastened by the bolt 4. In this case, a bolt insertion hole 12 is formed in the cap 6 so as to open on the mating surface 10, and the semi-annular portion 2 is formed.
A female screw hole 13 is formed so as to be positioned coaxially with each bolt insertion hole 12. In the figure, 14 is a piston pin hole formed in the small end 1.

The rod member 3 and the cap 6 are forged products simultaneously forged in the connecting rod-shaped cavity, and the opposing mating surfaces 8 and 10 are formed by the flow of material during forging as shown in FIG. It has innumerable concave portions a ₁ and a ₂ and convex portions b ₁ and b ₂ which are formed and have a fitting relationship with each other.

As described above, since the rod member 3 and the cap 6 are forged products made of Al alloy, they are lightweight and have high strength. Further, between the mating surfaces 8 and 10 of the rod member 3 and the cap 6 which face each other, the mating surfaces 8 and 1
Misalignment in the direction parallel to 0 can be reliably prevented by the innumerable recesses and protrusions a ₁ , a ₂ , b ₁ and b ₂ which are fitted to each other.

In this case, each concave portion, convex portion a ₁ , a ₂ , b ₁ ,
Since b ₂ is formed by the flow of the material, it is extremely irregularly arranged, and it is a very small amount that cannot be obtained by machining.
The stress generated between them is surely dispersed, and the mating surfaces 8,
The durability of the concavo-convex fitting structure in 10 can be improved.

Next, the connecting rod C to which the powder forging method is applied
The manufacturing method of will be described.

(A) As shown in FIG. 3, a first powder preform 15 having a shape similar to the shape of the rod member 3 is cold compression molded using an Al alloy powder. In this case, the female screw hole 13 is formed in the portion 16 corresponding to the semi-annular portion 2.
17 is not formed and corresponds to the small end 1
The piston pin hole 14 is not formed in the.

As shown in FIG. 4, a second powder preform 18 having a shape similar to the shape of the cap 6 is cold compression molded using an Al alloy powder. In this case, the second
The bolt insertion hole 12 is not formed in the powder preform 18.

(B) Both powder preforms 15 and 18 are heated using a high frequency heating furnace.

(C) As shown in FIG. 5, the first and second powder preforms 15, 15 are formed in the connecting rod-shaped cavity 21 formed in the lower die 20 of the powder forging die 19.
18 is a surface 22 corresponding to the mating surfaces 8 and 10,
23 are installed facing each other.

(D) The rod member 3 and the cap 6 are obtained by simultaneously forging the first and second powder preforms 15 and 18. The mating surfaces 8 and 10 of the rod member 3 and the cap 6, which face each other, have a myriad of concave and convex portions a ₁ ,
a ₂ , b ₁ , and b ₂ are formed. After the forging process, the mating surfaces 8 and 10 of the rod member 3 and the cap 6 are in an attached state, but they are easily separated after the mold release.

(E) The rod member 3 is machined to form the piston pin hole 14, the female screw hole 13 and the like, and the cap 6 is machined to form the bolt insertion hole 12.

(F) The mating surfaces 8 and 10 of the rod member 3 and the cap 6 which are opposed to each other are fitted to each other by fitting the concave portions and the convex portions a ₁ , a ₂ , b ₁ and b ₂ thereof to each other, The cap 6 is fastened to the member 3 with the bolt 4.

(G) The crank pin hole 11 is finished by machining the inner peripheral surface of the crank pin hole 11 formed by the two semicircular recesses 7 and 9.

According to the above manufacturing method, since the mating surfaces 8 and 10 of the rod member 3 and the cap 6 are not required to be machined, the number of manufacturing steps and the manufacturing cost can be reduced accordingly, and the rod member can be reduced. Unlike the case in which the connecting rod material in which the cap 3 and the cap 6 are integrated is subjected to a cutting process and divided into two, the material is not wasted due to the provision of the cutting allowance, and at the same time, the number of manufacturing steps can be reduced.

A specific example will be described below.

An Al alloy powder was produced by preparing a molten metal having an Al alloy composition such as Al _91.5 Fe _5.5 Ti ₁ Si ₂ (numerical value is atomic%), and then performing an air atomizing method using the molten metal. After that, the Al alloy powder was classified to obtain a first Al alloy powder having a particle size of 149 μm or less.

Further, a molten metal having an Al alloy composition such as A2024-25 wt% Si was prepared, and then the air atomizing method and the classification treatment were performed in the same manner as described above to obtain a grain size of 149 μm.
A second Al alloy powder of m or less was obtained.

Example 1 Using the first Al alloy powder, a connecting rod C ₁ was manufactured according to the above manufacturing example.

In the compression molding of the first powder preform 15, the compression pressure was set to 5 t / cm ^2, and the relative density of the first powder preform 15 was about 80%. In the compression molding of the second powder preform 18, the compression pressure was set to 5 t / cm ^2, and the relative density of the second powder preform 18 was about 80%. In the high frequency heating process, 853 of both powder preforms 15 and 18 were taken in about 4 minutes.
The temperature was raised to K and the temperature was maintained for 10 seconds for degassing. In the forging step, the temperature of the mold 19 was set to 473 K and the pressing force was set to 8 t / cm ² , and this step was immediately applied to both the powder preforms 15 and 18 after heating. The relative density of the rod member 3 and the cap 6 is 99.
8% or more, and the mating surfaces 8 and 10 facing each other of these 3 and 6 were provided with innumerable concave and convex portions a ₁ , a ₂ , b ₁ and b ₂ . The weight of connecting rod C ₁ after machining is 320
It was g.

[Embodiment 2] A second raw material powder for the cap 6 is used.
A connecting rod C ₂ having the same structure as in Example 1 was manufactured except that the Al alloy powder was used. In this connecting rod C ₂ , the rod member 3 and the cap 6
The mating surfaces 8 and 10 facing each other are innumerable deeper concaves and convex portions a ₁ , a ₂ , b ₁ and b ₂ than in the case of the first embodiment due to the change of the materials. Was equipped with. The weight of connecting rod C ₂ after machining was 316 g.

[Comparative Example] As shown in FIG. 6, the first and second powder preforms 1 were prepared using the first Al alloy powder.
An integral type powder preform 24 having a shape in which 5, 18 were connected in series was cold formed and compression molded. The compaction pressure was set to 5 t / cm ² and the relative density of the monolithic powder preform 24 was about 80%. Thereafter, a heat treatment and a forging process are sequentially performed under the same conditions as in Example 1 to manufacture an integral connecting rod material, and the integral connecting rod material is further divided into a rod member 3 and a cap 6 by cutting. A finishing process for the mating surfaces 8 and 10 was performed to manufacture a connecting rod C ₃ . Weight of connecting rod C ₃ after machining is 320g
Met.

Next, a single-body fatigue test was conducted on the connecting rods C _{1 to} C ₃ manufactured in Examples 1 and 2 and Comparative Example. In this test, as shown in FIG. 7, for example, the rods 25 and 26 are passed through the piston pin hole 14 and the crank pin hole 11 of the connecting rod C ₁ , respectively.
Both ends of 26 were supported by a hydraulic fatigue tester, and a tensile load was repeatedly applied to the connecting rod C ₁ at a temperature of 423 K and R = 0.1.

FIG. 8 shows the results of a single fatigue test for each connecting rod C _{1 to} C ₃ . In this type of single unit fatigue test, a practical connecting rod has a durability load of 3500 for 10 ⁷ times.
Must be kg.

As is apparent from FIG. 8, the connecting rods C ₁ and C ₂ according to Examples ₁ and ₂ satisfy the above requirements.
This is the mating surfaces 8, 1 of the rod member 3 and the cap 6.
The positional deviation between 0 is concave, convex part a ₁ , a ₂ ,
This is due to the fact that the stress is received by both the rod member 3 and the cap 6 while being prevented by b ₁ and b ₂ .

On the other hand, the connecting rod C ₃ according to the comparative example is used.
Has a durability load of 3200 kg at 10 ⁷ times and cannot meet the above requirement. In this connecting rod C ₃ , the breakage occurred from the large end shoulder S (see FIG. 1) as the starting point. This is because the positional deviation occurs between the mating surfaces 8 and 10 of the rod member 3 and the cap 6,
Only that is stressed.

Regarding the weight of the connecting rod, connecting rod C
₁Weighs 320 g, connecting rod C ₂Weighs 316g
And the weight of steel connecting rods with the same volume as these is 5
It is 40 g. Therefore, connecting rod C₁, C₂Is steel
We have achieved a weight reduction of about 40% compared to the connecting rod made by
As a result of this weight reduction, the maximum speed of the internal combustion engine has been increased to approximately 65
It is possible to improve 0 rpm. In addition, reduction of manufacturing man-hour
The manufacturing cost can be reduced by about 3% with a small amount.

As prior art, for the same purpose as the present invention,
As shown in FIG. 9, using steel powder, it is of the same type as in the comparative example, and has a portion 16 corresponding to the semi-annular portion 2 and a portion 27 corresponding to the cap 6 on the inner peripheral surface of the crankpin hole 11. A powder preform 29 having notches 28 at both boundaries is cold-compressed, and then the powder preform 29 is subjected to forging to manufacture an integral connecting rod material, and thereafter, an integral connecting rod material. There is known a manufacturing method in which the rod member 3 and the cap 6 are ruptured by pulling the rod member 3 and the cap 6 by utilizing cracks caused by the notches 28.

In order to apply this technique, as shown in FIG. 10, when the connecting rod material 30 using the first Al alloy powder was fractured by pulling, the fracture line 32 obliquely progressed from both cracks 31 caused by the notches. In addition, part of the portion along the fracture line 32 was plastically deformed, and the portion 33 on the rod member side and the portion 34 on the cap side could not be matched.

When a low toughness Al alloy powder is used,
Although the fracture line 32 progresses in a substantially straight line, such an Al alloy is unsuitable as an Al alloy for connecting rods.

Therefore, it was found that the above-mentioned prior art cannot be applied as a method for producing an Al alloy connecting rod.

The present invention is not limited to the connecting rod and the manufacturing method thereof, but is also applicable to, for example, a half bearing member and the manufacturing method thereof.

[0047]

According to the invention as set forth in claim 1, the misalignment between the mating surfaces of the first and second halves made of light alloy in the direction parallel to the mating surfaces is innumerable. It can be securely prevented by fitting the concave and convex parts of the shaft, and the durability of the concave and convex fitting structure is also high, and it is lightweight and has high strength and has a long life. A clamping member can be provided.

According to the fourth aspect of the invention, the shaft holding member can be manufactured inexpensively and efficiently.

[Brief description of drawings]

FIG. 1 is a fragmentary plan view of a connecting rod.

FIG. 2 is an enlarged view of a portion indicated by an arrow 2 in FIG.

FIG. 3 is a perspective view of a first powder preform.

FIG. 4 is a perspective view of a second powder preform.

FIG. 5 is a cross-sectional plan view showing a state in which first and second powder preforms are installed in a forging die.

FIG. 6 is a plan view showing an example of an integrated powder preform.

FIG. 7 is an explanatory diagram showing a single-body fatigue test method for connecting rods.

FIG. 8 is a graph showing the results of a single-body fatigue test on various connecting rods.

FIG. 9 is a plan view showing another example of the integrated powder preform.

FIG. 10 is a plan view of an essential part of a connecting rod material.

[Explanation of symbols]

1 Small End 2 Semi-annular Part 3 Rod Member (First Half) 4 Bolt (Screw Member) 5 Large End 6 Cap (Second Half) 7,9 Semi-Circular Recess 8,10 Mating Surface 11 Crank Pin Hole (Shaft insertion hole) 15, 18 First and second powder preforms 19 Mold 21 Cavity 22, 23 Surface C Connecting rod a ₁ , a ₂ Recessed portion b ₁ , b ₂ Convexed portion

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Masahiko Minemi Inventor Masahiko Minami 1-4-1, Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. No. 1 Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Yuge Takano 1-1-1 Kunyo Kita, Itami City, Hyogo Prefecture Sumitomo Electric Industries Itami Works (72) Inventor Kaji Toshihiko Itami City, Hyogo Prefecture Kunyo Kita 1-1-1 Sumitomo Electric Industries Itami Works

Claims (5)

[Claims] 1. A semi-circular recess (7, 9) having first and second halves (3, 6) respectively having mating surfaces (8, 10) at both ends in the circumferential direction. Half body (3,
6) is a plurality of screw members (4) in a state where the mating surfaces (8, 10) facing each other are matched and the shaft insertion hole (11) is formed by the semicircular recesses (7, 9). In the shaft clamping member to be fastened, the first and second halves (3, 6) are forged products which are made of a light alloy and simultaneously forged in the cavity (21) in the shape of the shaft clamping member. , The opposing mating surfaces (8, 10) are
Is formed by the flow of the material during forging countless concave in one another fitting relationship, the convex portion _{(a 1, a 2, b} 1, b 2) Jikukyo support member, characterized in that it comprises a. 2. The shaft holding member is a connecting rod (C) for an internal combustion engine, and the first half body (3) has a small end portion (1) at one end and a large end semi-annular portion at the other end. (2) are rod members respectively, and the second half body (6) is fastened to the semi-annular portion (2) by the screw member (4) and cooperates with the semi-annular portion (2). Shaft holding member according to claim 1, characterized in that it is a semi-annular cap which forms the large end (5) with. 3. The first and second halves (3,6) are A
The shaft holding member according to claim 1 or 2, which is made of an L alloy. 4. Semicircular recesses (7, 9) are provided with first and second halves (3, 6) having mating surfaces (8, 10) respectively at both ends in the circumferential direction, and the first and second halves are provided. Half body (3,
6) is a plurality of screw members (4) in a state where the mating surfaces (8, 10) facing each other are matched and the shaft insertion hole (11) is formed by the semicircular recesses (7, 9). In manufacturing a shaft holding member to be fastened, first and second preforms (1) having a shape similar to that of the first and second halves (3, 6) and made of a light alloy are provided.
5,18) and both preforms (15,1)
8) Step of heating and both preforms (15, 18)
The surfaces (22, 23) of the preforms (15, 18) corresponding to the mating surfaces (8, 10) are opposed to each other in the cavity (21) of the shaft clamping member shape of the mold (19). And the first and second preforms (15, 18) are subjected to forging at the same time, and the opposing mating surfaces (8, 10) are formed by the flow of material during forging. A step of obtaining the first and second halves (3, 6) having innumerable concave and convex portions (a ₁ , a ₂ , b ₁ , b ₂ ) that are in a fitting relationship with each other; When the second half body (3, 6) is fastened by the screw member (4), the concave portion and the convex portion (a ₁ ,
method for producing Jikukyo support member, which comprises using a step of _{a 2, b 1, b 2} ) Mate. 5. The first and second preforms (1
5, 18) is a powder preform made of an Al alloy powder, and the powder forging process is applied as the forging process.