JP3248407B2 - Internal combustion engine tappet member with strong bonding of chip material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tappet member for an internal combustion engine in which a tip material made of tungsten carbide (hereinafter, referred to as WC) -based cemented carbide is firmly diffusion-bonded to a low-alloy steel tappet body. It is about.

[0002]

2. Description of the Related Art Conventionally, as a tappet member of an internal combustion engine such as a diesel engine or a gasoline engine, for example, as described in Japanese Patent Application Laid-Open No. 62-182406 and as schematically illustrated in FIG. The top surface 1a on the cam contact surface side of the tappet body 1 which is usually formed by cold forging and is made of carbon steel, alloy steel or the like has one of metal carbides, nitrides, and borides. Seeds and Ni
Alternatively, there is known a tappet member formed by joining a chip material 2 made of a Ni alloy and liquid phase sintering thereof at the same time.

[0003]

On the other hand, in recent years, the output and performance of an internal combustion engine have been remarkably increased, and accordingly, the tappet member, which is a structural member of the internal combustion engine, has been used under more severe conditions. In the conventional tappet member described above, the bonding strength between the tappet body and the tip material is not sufficient in the above-described conventional tappet member, so that under severe operating conditions, peeling is apt to occur between the two, and the reliability is low. There is a problem in the point.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoints, as a result of conducting research to improve the joining strength of the tip material constituting the tappet member to the tappet body, the tappet body was determined by weight% (hereinafter,%
Indicates weight%), C: 0.13 to 0.5%, S
i: 0.15 to 0.35%, Mn: 0.3 to 1.2%, Cr: 0.4 to 3.5%, and, if necessary, Ni: 0.4 to 4 0.5%, Mo: 0.15 to 0.7%, and the remainder is specified as a low alloy steel having a composition of Fe and unavoidable impurities, and a cam of the low alloy steel. the top surface of the contact surface side, Co: 25~30%, P: 0.1~1%, chromium carbide (hereinafter, indicated by _{Cr 3 C 2): 0.5~10%} , Fe if necessary When the tip material made of a WC-based cemented carbide made of a sintered body having a composition composition of 0.1 to 3%, WC: remaining, is diffusion-bonded, in the resulting tappet member, Si of the tappet body and the tip material are obtained. The wettability of the tip material to the tappet body during diffusion bonding is significantly improved by the interaction of P constituting Both were adhesion improving significantly to the tappet body of the chip material by the action of the Cr ₃ C ₂ was dissolved in Co constituting the binder phase of the chip material, the chip material, to very firmly bonded to the tappet body And the WC-based cemented carbide is hard, so that a study result was obtained that the WC-based cemented carbide also has excellent wear resistance.

[0005] The present invention has been made based on the above research results, wherein: C: 0.13 to 0.5%, Si: 0.15 to 0.35%, Mn: 0.3 to 1 0.2%, Cr: 0.4 to 3.5%, and, if necessary, Ni: 0.4 to 4.5%, Mo: 0.15 to 0.7%. One or two kinds, and the remainder is composed of a low-alloy steel tappet body having a composition of Fe and inevitable impurities, on the top surface on the cam contact surface side, Co: 25 to 35%, P: 0.1 _{~1%, Cr 3 C 2:} 0.5~10%, optionally Fe: 0.1 to 3%, WC: remainder, consisting of a sintered body of blend composition consisting of WC-based cemented carbide tip The present invention is characterized in that an internal combustion engine tappet member is formed by diffusion bonding materials and has a strong bonding of a chip material.

Next, in the tappet member of the present invention, the reason why the component composition of the tappet body and the compounding composition of the tipping material are limited as described above will be described. A. Ingredient Composition of Tappet Body (a) C The C component has a function of improving the strength by forming a solid solution in a base material. However, if the content is less than 0.13%, a desired strength improving effect cannot be obtained. If the content exceeds 0.5%, the toughness will decrease.
It was determined to be 13 to 0.5%. Preferably, 0.2 to
A content of 0.4% is good.

(B) Si The Si component has the effect of improving the wettability with the tip material by the coexistence of P in the tip material during the diffusion bonding, thereby improving the adhesion of the tip material to the tappet body. There is,
If the content is less than 0.15%, the desired effect cannot be obtained in the above-mentioned action, while if the content exceeds 0.35%, the strength is reduced.
It was determined as 5 to 0.35%. Desirably 0.2-0.3%
Is good.

(C) Mn The Mn component has a function of improving the toughness by forming a solid solution in the base material, but if its content is less than 0.3%, the desired effect of improving the toughness cannot be obtained. If the amount exceeds 1.2%, the strength rapidly decreases, so the content was determined to be 0.3 to 1.2%. Desirably 0.7-1%
Is good.

(D) Cr The Cr component has a function of improving the heat resistance by forming a solid solution in the base material, but if its content is less than 0.4%, the desired effect of improving the heat resistance cannot be obtained. If the content exceeds 3.5%, the toughness will decrease, so the content was determined to be 0.4 to 3.5%. Desirably, the content is 1 to 3%.

(E) Ni and Mo Since these components have a function of further improving the strength by forming a solid solution in the base material, they are contained as necessary. Less than 4% and Mo:
If it is less than 0.15%, the desired effect of improving the strength cannot be obtained, while if its content exceeds 4.5% Ni and 0.7% Mo, the toughness is reduced. Ni: 0.4 to 4.5%, Mo: 0.15 to 0.7
%. Preferably, Ni: 2-3%, Mo:
The content is preferably 0.3 to 0.5%.

B. Composition of chip material (a) Co The Co component has the effect of forming a binder phase and improving the strength and toughness. If the proportion is less than 25%, the desired effect cannot be obtained. If the ratio exceeds 35%, the hardness rapidly decreases, and a decrease in wear resistance is inevitable. Therefore, the ratio is set to 25 to 35%. Note that the ratio is preferably 28 to 32%.

(B) The PP component improves the sinterability and enables liquid phase sintering, and coexists with the Si of the tappet body to wet the tip material into the tappet body during diffusion bonding. However, if the ratio is less than 0.1%, the desired effect cannot be obtained, and if the ratio exceeds 1%, the embrittlement phenomenon appears. The ratio was defined as 0.1-1%. Preferably, 0.3
A ratio of ~ 0.7% is good.

(C) Cr ₃ C _{2 The} Cr ₃ C ₂ component forms a solid solution with the binder phase, and is combined with Si of the tappet body and the effect of improving the wettability by the P of the tip material during diffusion bonding. It has an effect of remarkably improving the adhesion to the main body, but the ratio is 0.1%.
If the content is less than 5%, the desired effect cannot be obtained, and if the content exceeds 10%, the strength decreases. Therefore, the content is set to 0.5 to 10%. Desirably, the ratio is 4 to 8%.

(D) Fe Since the Fe component has a function of improving the hardness by forming a solid solution in the binder phase, it is contained as necessary. Since the desired effect of improving the hardness cannot be obtained and the strength whose ratio exceeds 3% decreases, the ratio is set to 0.1 to 3%. Desirably, the ratio is 0.3 to 1%.

Further, the tappet member of the present invention generally has the above-mentioned WC-based cemented carbide tip material placed on the top surface of the above-mentioned low alloy steel tappet body on the cam contact surface side. In a vacuum or reducing atmosphere, or in a non-oxidizing atmosphere, a temperature of 1200 to 1300 ° C.
After holding for 20 minutes, a diffusion bonding process is performed under cooling conditions, and then, in a normal carburizing gas atmosphere, at a temperature of 850 to 900 ° C. for 150 to 200 minutes, and then immersed in oil having an oil temperature of 120 to 140 ° C. It is manufactured by performing oil quenching and heat treatment of tempering in air at a temperature of 150 to 200 ° C. for 100 to 150 minutes.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the tappet member of the present invention will be specifically described with reference to embodiments. First of all, the shape and outer diameter shown in FIG.
× Length: Tappet bodies A to 51 having dimensions of 51 mm and made of low alloy steel having the component compositions shown in Table 1, respectively.
In order to prepare P and form a chip material, WC powder, Cr ₃ C ₂ powder, Co-P alloy (containing 35% P) having a particle size of 100 mesh or less are used as raw material powders.
Powder, Fe-P alloy (containing 25% P) powder, Fe powder, Co powder, and graphite powder, and these raw material powders were blended into the blending composition shown in Table 2 and mixed.
diameter under a pressure of ⁿ / cm ^2: 31mm φ × thickness: was press molded into a green compact having a size of 3 mm, these compact, 1 ×
In a vacuum of 10 ^-2 torr, sintering is performed at a predetermined temperature in the range of 1200 to 1300 ° C. for 60 minutes, and each of them is a WC-based super sintered body having a theoretical density ratio of 95% or more. Chip materials a to q each made of a hard alloy were manufactured. Next, these tip materials a to q are mounted as shown in the drawing on the top surfaces of the tappet bodies A to P on the cam contact surface side in combinations shown in Table 3, and in this state, 1 × 10 ^{− Two}
After holding at a temperature of 1250 ° C. for 80 minutes in a vacuum of torr, diffusion bonding treatment of forced cooling by blowing nitrogen gas was performed,
Then, in a normal carburizing gas atmosphere, the temperature: 880 ° C. and 18
After holding for 0 minutes, the tappet members 1 to 15 of the present invention and comparative tappet members are subjected to oil quenching immersed in oil having an oil temperature of 130 ° C. and tempering in air at 180 ° C. for 120 minutes. 1 to 5 were each manufactured.

The comparative tappet members 1 to 5 are components that affect the bonding strength between the tappet body and the tip material, ie, Si in the pellet body and P and Cr in the tip material.
The content ratio of any one of ₃ C ₂ is out of the range of the present invention.

Next, the Vickers hardness of the tip material was measured for the various tappet members obtained as a result, and this was incorporated into a 6-cylinder, 12-valve, 8200 cc, 210 hp diesel engine.
pm, operation time: 200 hours of high-speed rotation conditions, actual machine tests were performed to measure the maximum wear depth of the tip material on the cam sliding surface and to evaluate the joining strength of the tip material to the tappet body. The joint surface between the two was observed along the outer periphery, and the number of cracks caused by peeling was measured. Further, for the purpose of evaluating the bonding strength, the shear strength of the bonding surface was also measured. Table 3 shows the results of these measurements.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

As can be seen from the results shown in Tables 1 to 3, the tappet members 1 to 15 of the present invention have excellent abrasion resistance without causing a peeling phenomenon of the tip material from the tappet body despite high-speed operation. As shown in the comparative tappet members 1 to 5, any one of Si of the tappet body and P and Cr ₃ C ₂ of the tip material, which greatly affect the joining between the tappet body and the tip material, as shown in the comparative tappet members 1 to 5. It is clear that if the content ratio deviates from the range of the present invention to the lower side, a strong bonding strength cannot be secured to them. As described above, the tappet member of the present invention
Since the tip material constituting this is remarkably firmly joined to the top surface of the tappet body on the side of the cam abutting surface, it can sufficiently cope with high speed and high performance of the internal combustion engine, and is excellent for a long time. It demonstrates its performance.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view illustrating a tappet member of an internal combustion engine.

[Explanation of symbols]

 Reference Signs List 1 Tappet body 1a Top surface of tappet body on cam contact surface side 2 Tip material

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI C22C 38/44 C22C 38/44 F01L 1/14 F01L 1/14 B (72) Inventor Mikikazu Kobayashi Okura, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture No. 10 in the Mitsubishi Motors Corporation (72) Inventor Toshiharu Matsui 10 in Okura-cho, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Within Mitsui Automotive Industry Co., Ltd. (72) Kenichi Miyauchi 10 in Okura-cho, Nakahara-ku, Kawasaki-shi, Kanagawa Address: Mitsubishi Motors Corporation (56) References JP-A-63-299874 (JP, A) JP-A-3-291361 (JP, A) JP-A-3-146297 (JP, A) JP-B-6 -63054 (JP, B2) JP 5-12420 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 38/00 301 C22C 38/00 304 B23K 20/00 310 C22C 29/08 C22C 38/18 C22C 38/44 F01L 1/14

Claims (4)

(57) [Claims] C .: 0.13-0.5%, Si: 0.15-0.35%, Mn: 0.3-1.2%, Cr: 0.4-3. 5%, Co: 25 to 35%, P: 0.1 to 1% on the top surface on the cam contact surface side of the low alloy steel tappet body having a composition consisting of Fe and unavoidable impurities. Chromium carbide: 0.5 to 10%, Tungsten carbide: Remainder, Tungsten carbide-based cemented carbide chip material consisting of a sintered body having a composition of: Engine tappet members. 2. In% by weight, C: 0.13-0.5%, Si: 0.15-0.35%, Mn: 0.3-1.2%, Cr: 0.4-3. Ni: 0.4 to 4.5%, Mo: 0.15 to 0.7%, and one or two of the following, with the balance being Fe and unavoidable impurities. Co: 25 to 35%, P: 0.1 to 1%, Chromium carbide: 0.5 to 10%, Tungsten carbide on the top surface of the low-alloy steel tappet body having a composition consisting of: : An internal combustion engine tappet member having a strong bonding of the tip material, formed by diffusion bonding of a tungsten carbide-based cemented carbide tip material made of a sintered body having a composition having a composition of: 3. In% by weight, C: 0.13-0.5%, Si: 0.15-0.35%, Mn: 0.3-1.2%, Cr: 0.4-3. 5%, Co: 25 to 35%, P: 0.1 to 1% on the top surface on the cam contact surface side of the low alloy steel tappet body having a composition consisting of Fe and unavoidable impurities. Chromium carbide: 0.5 to 10%, Fe: 0.1 to 3%, Tungsten carbide: Remainder, formed by diffusion bonding of a tungsten carbide-based cemented carbide chip made of a sintered body having a composition of: , A tappet member for an internal combustion engine with strong bonding of the tip material. 4. In% by weight, C: 0.13-0.5%, Si: 0.15-0.35%, Mn: 0.3-1.2%, Cr: 0.4-3. Ni: 0.4 to 4.5%, Mo: 0.15 to 0.7%, and one or two of the following, with the balance being Fe and unavoidable impurities. Co: 25 to 35%, P: 0.1 to 1%, chromium carbide: 0.5 to 10%, and Fe: on the top surface of the low-alloy steel tappet body having a composition consisting of: Tungsten carbide: 0.1% to 3%: A tappet member for an internal combustion engine having a strong bonding of a chip material, which is formed by diffusion bonding a chip material made of a tungsten carbide-based cemented carbide made of a sintered body having a composition of: