JP2816926B2 - Shaft holding member and manufacturing method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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

Conventionally, connecting rods for internal combustion engines are generally made of carbon steel for mechanical structures (see, for example, "Automobile Encyclopedia" published by Asakura Shoten in 1978).

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

[0005]

In view of the above demand for weight reduction and cost reduction, the connecting rod is made of light alloy A
It is conceivable that it is composed of 1 alloy.

However, connecting rods made of Al alloy are
Due to the inherently lower stiffness of the alloy compared to that of steel, elastic deformation occurs under relatively low stress, so that the rod member and the cap are parallel to the mating surface. The position of the rod member is likely to be displaced, and as a result, a situation occurs in which stress is applied only by the rod member, so that the life of the rod member is significantly reduced.

In order to solve the above-mentioned problems, it is effective to increase the axial force of the bolt. However, if such a means is adopted, the Al alloy has low rigidity and low creep strength with respect to steel. Therefore, a new problem such as a depression of the bolt head seat surface arises.

In view of the foregoing, the present invention employs a relatively simple means to reliably prevent the displacement between the mating surfaces of the first and second halves made of a light alloy. An object is to provide a holding member.

Further, according to the present invention, the shaft holding member can be manufactured at low cost.
It is another object of the present invention to provide the above-mentioned manufacturing method which can be manufactured efficiently.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to a first and a second concave portions each having mating surfaces at both circumferential ends of a semicircular concave portion.
The first and second halves are arranged such that their opposing mating surfaces coincide with each other, and the two shafts are fastened by a plurality of screw members with a shaft insertion hole formed by both semicircular recesses. In the member, the first and second halves are a forged product made of a light alloy and forged simultaneously in a cavity in the shape of a shaft holding member, wherein the opposing mating surfaces are It is characterized by having a myriad of concaves and convexes formed by the flow of the material and in a mating relationship with each other.

The present invention comprises first and second halves having mating surfaces at both ends in the circumferential direction of the semicircular concave portion, and the first and second halves have both opposing mating surfaces. When manufacturing a shaft holding member to be fastened with a plurality of screw members in a state where the shaft insertion hole is formed by both semicircular recesses, the shape has a shape similar to the shape of the first and second halves. A step of obtaining first and second preforms made of a light alloy, a step of heating both preforms, and a step of placing both preforms in a cavity in the shape of a shaft clamping member in a mold, on the mating surface of the preforms. Installing the corresponding surfaces facing each other, forging the first and second preforms simultaneously,
Obtaining said first and second halves having innumerable concave and convex portions in the mating relationship formed by the flow of the material being forged on said opposing mating surfaces; And when the second half is fastened by the screw member, a step of fitting the concave and convex portions of the both mating surfaces is used.

[0012]

In the shaft holding member, the first and second halves are forged parts made of a light alloy, so that they are lightweight and have high strength. In addition, misalignment between the opposing mating surfaces of the first and second halves in the direction parallel to the mating surface is reliably prevented by the countless concave and convex portions fitted to each other.

In this case, since each of the concave and convex portions is formed by the flow of the material, they are extremely irregularly arranged, and are minute, which cannot be obtained by machining. The stress generated therebetween can be surely dispersed, and the durability of the concave-convex fitting structure on the mating surfaces can be improved.

On the other hand, according to the manufacturing method, since machining is not required for the mating surfaces of the first and second halves, the number of manufacturing steps and manufacturing costs can be reduced accordingly. As in the case where the connecting rod material in which the second half is integrated and the connecting rod material is cut and divided into two parts, no material is wasted due to the provision of the cutting margin, and at the same time, the number of manufacturing steps is reduced.

[0015]

In FIG. 1, a connecting rod C for an internal combustion engine as a shaft holding member is made of an aluminum alloy as a light alloy, and has a small end 1 at one end and a semi-annular portion for a large end at the other end. 2 and a plurality of, in the illustrated example, two, steel bolts 4 as screw members, which are connected to the semi-annular portion 2 and a semi-annular portion 2, respectively. A as the second half forming the large end 5 in cooperation with
1 and a semi-annular cap 6 made of an alloy.

The semi-annular portion 2 of the rod member 3 has a semi-circular recess 7
The cap 6 also has mating surfaces 10 at both ends in the circumferential direction of the semicircular recess 9 in the same manner. 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 form a crankpin hole 11 as a shaft insertion hole. Fastened by bolts 4. In this case, a bolt insertion hole 12 is formed in the cap 6 so as to open to both mating surfaces 10 thereof.
A female screw hole 13 is formed so as to be coaxial with each bolt insertion hole 12. In the figure, reference numeral 14 denotes a piston pin hole formed in the small end 1.

The rod member 3 and the cap 6 are forgings which are simultaneously forged in a connecting rod-shaped cavity. Opposing mating surfaces 8 and 10 are formed by the flow of material during forging as shown in FIG. It has an infinite number of concave portions a ₁ and a ₂ and convex portions b ₁ and b ₂ that are formed and fit with each other.

As described above, since the rod member 3 and the cap 6 are forged parts made of an Al alloy, they are lightweight and have high strength. The mating surfaces 8, 1 between the opposing mating surfaces 8, 10 of the rod member 3 and the cap 6 are also provided.
The displacement in the direction parallel to 0 is reliably prevented by the countless concave and convex portions a ₁ , a ₂ , b ₁ , b ₂ fitted together.

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

Next, a connecting rod C to which a powder forging method is applied
A method of manufacturing the device 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 compression molded in a cold state using an Al alloy powder. In this case, the portion 16 corresponding to the semi-annular portion 2 has the female screw hole 13
Is not formed, and the portion 17 corresponding to the small end 1 is not formed.
Is not formed with a piston pin hole 14.

As shown in FIG. 4, a second powder preform 18 having a shape similar to the shape of the cap 6 is compression-molded in a cold state using an Al alloy powder. In this case, the second
No bolt insertion hole 12 is 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 and 20 are placed in the connecting rod-shaped cavity 21 formed in the lower die 20 of the powder forging die 19.
18 to the surfaces 22, corresponding to the mating surfaces 8, 10;
23 are placed facing each other.

(D) The first and second powder preforms 15 and 18 are simultaneously forged to obtain the rod member 3 and the cap 6. Due to the flow of the material during forging, the countless concave and convex portions a ₁ ,
a ₂ , b ₁ and b ₂ are formed. After the forging process, the mating surfaces 8, 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 opposing mating surfaces 8 and 10 of the rod member 3 and the cap 6 are matched by fitting their concave and convex portions a ₁ , a ₂ , b ₁ and b ₂ to each other. The cap 6 is fastened to the member 3 with the bolt 4.

(G) The inner peripheral surface of the crankpin hole 11 formed by the two semicircular recesses 7 and 9 is machined to finish the crankpin hole 11.

According to the above-described manufacturing method, since machining for the mating surfaces 8 and 10 of the rod member 3 and the cap 6 is unnecessary, the number of manufacturing steps and manufacturing costs can be reduced accordingly, and the rod member can be reduced. As in the case where the connecting rod material in which the cap 3 and the cap 6 are integrated is cut into two to be cut into two parts, no material waste is caused by the provision of the cutting margin, and at the same time, the number of manufacturing steps is reduced.

Hereinafter, specific examples will be described.

A molten alloy having an Al alloy composition such as Al _91.5 Fe _5.5 Ti ₁ Si ₂ (atomic%) was prepared, and then the alloy was subjected to an air atomizing method to produce an Al alloy powder. Thereafter, the Al alloy powder was subjected to a classification treatment 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 A20224-25% by weight of Si was prepared, and then subjected to an air atomizing method and a classification treatment in the same manner as described above to obtain a particle size of 149 μm.
m or less of the second Al alloy powder was obtained.

[0033] Using Example 1 The 1Al alloy powder was produced connecting rod C ₁ in accordance with the above Preparation 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 at 5 t / cm ^2, and the relative density of the second powder preform 18 was about 80%. In the high-frequency heating step, both powder preforms 15 and 18 were 853 in about 4 minutes.
The temperature was raised to K, and the temperature was maintained for 10 seconds to perform degassing. In the forging process, the temperature of the mold 19 was set to 473 K, and the pressing force was set to 8 t / cm ² , and this process was immediately applied to the heated powder preforms 15 and 18. The relative density of the rod member 3 and the cap 6 is 99.
And at least 8%, both mating surfaces 8 and 10 facing each of them 3 and 6 was equipped with a myriad of concave, convex portions _{a 1, a 2, b 1} , b 2. Weight of the connecting rod C ₁ after machining 320
g.

Example 2 The raw material powder for the cap 6 was
Except that the Al alloy powder was prepared a connecting rod C ₂ having the same configuration under the same conditions as in Example 1. In this connecting rod C ₂ , the rod member 3 and the cap 6
The two mating surfaces 8, 10 facing each other have innumerable concave and convex portions a ₁ , a ₂ , b ₁ , b _{2 which} are deeper than the case of the first embodiment due to the change of their materials. It was equipped. Weight of the 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 by using a first Al alloy powder.
An integrated powder preform 24 having a shape in which 5, 18 were continuously connected was compression-molded in a cold state. The compression pressure was set at 5 t / cm ² and the relative density of the integral powder preform 24 was about 80%. Thereafter, a heating process and a forging process are sequentially performed under the same conditions as in Example 1 to produce an integrated connecting rod material, which is further cut into an integrated connecting rod material and divided into a rod member 3 and a cap 6. was produced connecting rod C ₃ is subjected to finishing of each mating surfaces 8 and 10. Weight of the connecting rod C ₃ after machining 320g
Met.

Next, single rod fatigue tests were performed on the connecting rods C _{1 to} C ₃ manufactured in Examples 1 and 2 and Comparative Example. This test, as shown in FIG. 7, for example, is passed through the rod 25 and 26 respectively in the piston pin hole 14 and the crank pin hole 11 of the connecting rod C _1, each rod 25,
26 both ends of and is supported on the hydraulic fatigue testing machine, the temperature 423K connecting rod C _1, was performed by adding repeated tensile load at R = 0.1.

FIG. 8 shows the results of a single fatigue test for each of the connecting rods C _{1 to} C ₃ . In this kind alone fatigue test, in practical use connecting rod, durable load is 10 ⁷ times 3500
kg.

As is clear from FIG. 8, the connecting rods C ₁ and C _{2 according to the first} and _second embodiments satisfy the above requirements.
This is because the mating surfaces 8, 1 of the rod member 3 and the cap 6
The position shift between 0 is concave and convex portions a ₁ , a ₂ ,
This is caused by the fact that stress is received by both the rod member 3 and the cap 6 while being prevented by b ₁ and b ₂ .

In contrast, the connecting rod C ₃ according to the comparative example
Has an endurance load of 10 ⁷ times of 3200 kg and cannot satisfy the above requirement. In the connecting rod C _3, the fracture has occurred starting from the large end shoulder S (see FIG. 1). This is because the displacement between the mating surfaces 8 and 10 of the rod member 3 and the cap 6 occurs, and the rod member 3
This is due to the fact that only stress was applied.

Regarding the weight of the connecting rod, the connecting rod C
₁Weighs 320 g, connecting rod C _TwoWeighs 316g
And the weight of a steel connecting rod of the same volume as these is 5
40 g. Therefore, connecting rod C₁, C_TwoIs steel
40% lighter than the connecting rod
As a result, the maximum rotation speed of the internal combustion engine can be reduced to about 65
It is possible to increase 0 rpm. Reduction of manufacturing man-hours
The manufacturing cost can be reduced by about 3%.

As prior art, for the same purpose as the present invention,
As shown in FIG. 9, a portion 16 corresponding to the semi-annular portion 2 and a portion 27 corresponding to the cap 6 are formed on the inner peripheral surface of the crankpin hole 11 by using steel powder, and are integrated as in the comparative example. A powder preform 29 having notches 28 at both boundaries is cold-formed and compacted, and then the powder preform 29 is forged to produce an integrated connecting rod material. Is known in which the rod member 3 and the cap 6 are broken by pulling using a crack caused by the two 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 broken by tension, a breaking line 32 progressed obliquely from both cracks 31 caused by the notch. However, a part of the portion along the breaking line 32 was plastically deformed, and the rod member-side portion 33 and the cap-side portion 34 could not be matched.

When a low toughness Al alloy powder is used,
Although the break line 32 proceeds substantially straight, such an Al alloy is not suitable as an Al alloy for connecting rods.

Therefore, it was found that the above prior art was not applicable as a method for manufacturing an Al alloy connecting rod.

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

[0047]

According to the first aspect of the present invention, the misalignment of the first and second halves made of light alloy between the mating surfaces in the direction parallel to the mating surfaces is reduced by the innumerable numbers existing on both the mating surfaces. The shaft can be reliably prevented by fitting the concave and convex portions of the shaft, and the concave and convex fitting structure has high durability, light weight, high strength and long life. A clamping member can be provided.

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

[Brief description of the 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 where first and second powder preforms are set in a forging die.

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

FIG. 7 is an explanatory view showing a unit fatigue test method for a connecting rod.

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

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

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Small end 2 Semi-annular part 3 Rod member (1st half) 4 Bolt (screw member) 5 Large end 6 Cap (2nd half) 7,9 Semicircular recess 8,10 Mating surface 11 Crank pin hole (shaft insertion hole) 15 and 18 first, face second powder preform 19 mold 21 cavity 22, 23 C the connecting rod a _1, a ₂ recess b _1, b ₂ protrusions

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiko Minemi 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda R & D Co., Ltd. (72) Inventor Yoshinobu Takeda 1-1-1-1 Kunyokita, Itami-shi, Hyogo No. Sumitomo Electric Industries, Ltd., Itami Works (72) Inventor Yoshie Takano 1-1-1, Koyo Kita, Itami-shi, Hyogo Prefecture, Japan Sumitomo Electric Industries, Ltd. Itami Works (72) Inventor Toshihiko Kaji, Itami Hyogo Prefecture 1-1-1, Kunyang-Kita, Sumitomo Electric Industries, Ltd. Itami Works (56) References JP-A-5-202922 (JP, A) JP-A-62-188705 (JP, A) JP-A-4- 59147 (JP, A) Japanese Utility Model Showa 64-53522 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16C 7/02 B21K 1/14

Claims (5)

(57) [Claims] 1. A first and a second half (3, 6) having mating surfaces (8, 10) at both circumferential ends of a semicircular recess (7, 9), respectively. Half (3,
6) is formed by a plurality of screw members (4) in a state where the opposing mating surfaces (8, 10) are matched and a shaft insertion hole (11) is formed by both semicircular recesses (7, 9). In the shaft holding member to be fastened, the first and second halves (3, 6) are forged products made of a light alloy and simultaneously forged in a cavity (21) in the shape of a shaft holding member. , The opposing mating surfaces (8, 10)
A shaft clamping member having a myriad of concaves and convexes (a ₁ , a ₂ , b ₁ , b ₂ ) formed by a flow of a material during forging and in a fitting relationship with each other. 2. The shaft holding member is a connecting rod (C) for an internal combustion engine, and the first half (3) has a small end (1) at one end and a semi-annular portion for a large end at the other end. (2), wherein the second half (6) is fastened to the semi-annular portion (2) by the screw member (4) and cooperates with the semi-annular portion (2). 2. The shaft holding member according to claim 1, wherein said shaft holding member is a semi-annular cap forming a large end (5). 3. The method according to claim 1, wherein said first and second halves (3, 6) are A
3. The shaft holding member according to claim 1, which is made of an alloy. 4. First and second halves (3, 6) having mating surfaces (8, 10) at both ends in the circumferential direction of the semicircular recesses (7, 9), and the first and second halves are provided. Half (3,
6) is formed by a plurality of screw members (4) in a state where the opposing mating surfaces (8, 10) are matched and a shaft insertion hole (11) is formed by both semicircular recesses (7, 9). In manufacturing the shaft holding member to be fastened, the first and second preforms (1) having a shape similar to the shape of the first and second halves (3, 6) and made of a light alloy are used.
5, 18), and both preforms (15, 1).
8) heating and both preforms (15, 18)
The surfaces (22, 23) corresponding to the mating surfaces (8, 10) of the preforms (15, 18) are opposed to each other in a cavity (21) in the shape of a shaft holding member in a mold (19). And forging the first and second preforms (15, 18) at the same time, and forming on the opposing mating surfaces (8, 10) by the flow of material during forging. Obtaining said first and second halves (3, 6) having innumerable concave and convex portions (a ₁ , a ₂ , b ₁ , b ₂ ) in a mating relationship with each other; When the second half (3, 6) is fastened by the screw member (4), the concave and convex portions (a ₁ ,
a ₂ , b ₁ , b ₂ ) to fit each other. 5. The first and second preforms (1).
5. The method for manufacturing a shaft holding member according to claim 4, wherein (5, 18) is a powder preform made of an Al alloy powder, and powder forging is applied as the forging.