JPS6030738B2 - Sintered oil-impregnated roller chain bushing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a competitive oil roller chain bushing that has high strength and hardness, and exhibits extremely excellent wear resistance in practical use.

Generally, a roller chain is used in various power transmission devices, and this roller chain consists of four components: a bush, a bush link plate, a pin, and a pin link plate.
It is well known that it is composed of parts.

In addition, bushings in roller chains in particular are required to have high strength and wear resistance, so conventional bushings are manufactured using plastic working and heat treatment rather than steel, which inevitably leads to high costs. It was something I couldn't get. Therefore, from the above-mentioned viewpoint, the present inventors developed a powder metallurgy method that can reduce the manufacturing cost of a roller chain bushing that has the high strength and excellent wear resistance required for a roller chain bushing. As a result of research, the component composition was changed to Cu:1
~7%, Cr:0.2~2.5%, C:0.5~1.2
%, Ni: 1 to 5%, and optionally P,
One or more of B and Sj: 0.05
~3%, with the remainder consisting of Fe and unavoidable impurities (the above weight %, hereinafter simply % means weight %), and the oil content is 5 to 35 volume %. The competitive roller chain bushing with a hardened surface layer has the same high strength and excellent wear resistance as the subordinate roller chain bushing, has excellent lubrication properties, and can be manufactured at low cost. We obtained this knowledge.

This invention was made based on the above knowledge, and the reason why the component composition and oil content were limited as described above will be explained below. [a} Cu The Cu component has the effect of solidifying into the substrate and improving the strength of the substrate, but if the content is less than 1%, the desired effect of improving the above effect cannot be obtained, whereas if the content exceeds 7% If it is contained, the hardness will be significantly lowered, so the content should be increased from 1 to 7.
%.

'b} C and Cr A part of each of the C and Cr components is dissolved in the base material to significantly improve the strength of the base material, and the other part forms Cr carbide to improve the hardness. Although they have the effect of improving wear resistance, C: less than 0.5% and Cr:
If the content is less than 0.2%, the desired effect of improving the above action cannot be obtained. On the other hand, if the content exceeds C: 1.2% and Cr: 2.5%, elongation and elongation will decrease. Therefore, C: 0.5 to 1.2% and Cr: 0.2 to 2.5% were determined, respectively.

'c} The NiNi component has the effect of increasing the hardenability by solidifying into the base material and improving the impact strength, thereby increasing the strength of the bush body, but if its content is less than 1%, it will not reach the desired level. The strength improvement effect cannot be obtained, and if the content exceeds 5%, the hardness decreases significantly and wear resistance deteriorates, so the content was set at 1 to 5%.

'd' P, B, and Si These components have the uniform effect of accelerating crystallization, making the pore shape mellow, and solidifying into the substrate to improve its strength, so these properties are particularly important. If the content is less than 0.05%, the desired effect of improving the above action cannot be obtained;
If the content exceeds 0.05%, arms will form, so the content was set at 0.05 to 3%.

'e} Oil content If the oil content is less than 5% by volume, the oil content is too small to ensure the desired lubricity, while if the oil content exceeds 35% by volume, the strength and wear resistance will deteriorate. Since this would cause rapid deterioration, the oil content was set at 5 to 3% by string capacity.

Next, the burnt striped oil-impregnated roller chain pushbutton of the present invention will be explained using examples and comparing with comparative examples.

As the raw material powder of the example, electrolytic steel powder with a particle size of 148hesh,
Same 20 hesh graphite powder, same 200 hesh Fe-Cr alloy (Cr: 13% content) powder, same 145 hesh
Hesh Ni powder, same 10hesh Fe-P alloy (P: 0.45% content) powder, same 145hesh Fe-B alloy (B: 20% content) powder, same 145hesh
Fe-Si alloy (containing 75% Si) powder of heSh and reduced iron powder of the same 10 heSh were prepared, and these raw material powders were blended into the composition shown in Table 1, and 0 stearin was added as a lubricant. Zinc acid: 0.5% was added and mixed, and then a green compact was molded at the same molding pressure shown in Table 1, and then this green compact was heated to 1140q0 in an ammonia decomposition gas atmosphere. It is condensed under the condition of holding for a long time, and then charged into a carbonitriding furnace, and while flowing a reaction gas containing ammonia into the furnace, the temperature:
After holding for a period of time, the carbonitriding treatment of oil quenching is not performed, then tempering treatment is performed in the air at a temperature of 160 qo for 1 hour, and finally vacuum oil immersion treatment is performed to achieve a composition that is substantially the same as the compound composition. The final component composition is:
5 side J Bushes (hereinafter referred to as comparative push) 1 to 10 were manufactured, respectively.

The oil content, surface hardness (Rockwell hardness A scale), and radial crushing strength of the inventive pushes 1 to 20 and comparative pushes 1 to 10 obtained as a result were measured, and the measurement results were combined with Table 1. Indicated. Next, using the above-mentioned pushes 1 to 20 of the present invention and comparison pushes 1 to 1, the conditions simulated for a practical roller chain, that is, the gap between the push and the inner hook is approximately 0.1 rib, and the surface roughness is 0.3~0. Aged steel shaft prepared to $ (surface hardness H
RC:50) is inserted into the push, and with a load of 120k9 applied to the push, the shaft is
Enemy. p. m. A wear test was carried out for 48 hours under the condition that the bushing was rotated at a rotational speed of 100. After the test, the wear amount (depth) of the inner diameter of the bush was measured and the occurrence of cracks was observed.

These results are also shown in Table 1. Q Satohina Table 1-2 As shown in Table 1, the present invention push 1 to 2 rivers,
Both have high strength and exhibit excellent wear resistance with no cracking, but due to their composition,
In comparison push 1 to 1, where the oil content (indicated by an asterisk in Table 1) is outside the scope of this invention, at least one of the properties (indicated by an asterisk in Table 1) is
It is clear that the results shown in Table 1 are inferior.

In addition, in the above example, a case was described in which a carburizing treatment was applied to the formation of a surface hardening layer under normal conditions, but in addition to this, known surface hardening treatments such as carburizing, nitriding, and further carburizing may also be used. Of course, similar results can be obtained even if a hardened surface layer is formed on the surface of the bush main body.

As mentioned above, according to the Akatsuki oil roller chain bushing of the present invention, high strength is ensured by the bushing body, and excellent lubricity and wear resistance are ensured by the oil-impregnated and surface hardened layer, so it is excellent. It can be used stably for a long period of time while maintaining its performance, and has industrially useful effects such as low manufacturing cost.

Claims (1)

[Claims] 1 Cu: 1-7%, Cr: 0.2-2.5%, C: 0
．． 5-1.2%, Ni: 1-5%, and the rest is Fe.
A sintered oil-impregnated roller chain bushing having a composition (the above weight %) consisting of and unavoidable impurities, and having a content of 5 to 35 weight % and a surface hardening layer. 2 Cu: 1-7%, Cr: 0.2-2.5%, C: 0
．． 5 to 1.2%, Ni: 1 to 5%, and further contains P,
One or more of B and Si: 0.05
A sintered oil-impregnated roller chain characterized by having a composition (wt%) containing ~3% and the remainder consisting of Fe and unavoidable impurities, and having a content of 5 to 35% by volume and a hardened surface layer. Butsuyuu.