JP3346286B2 - Synchronizer ring made of iron-based sintered alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronizer ring made of an iron-based sintered alloy having excellent strength, toughness and wear resistance.

[0002]

2. Description of the Related Art In recent years, manufacturing methods of iron-based sintered alloys have advanced, and various types of mechanical parts made of iron-based sintered alloys can be produced in large quantities with high precision. Synchronizer rings are also made of iron-based sintered alloys. Manufacturing has begun. As an example of a synchronizer ring made of an iron-based sintered alloy, a mixed powder composed of an Fe powder, a Cu powder and a graphite powder is press-molded, sintered, and Cu: 8.0 to 15.0% by weight, C:
2. Description of the Related Art A synchronizer ring comprising an iron-based sintered alloy containing 1.2 to 2.0% by weight, the balance being Fe and unavoidable impurities, and having a free Cu phase precipitated in a base material is known. I have. It is also known that the synchronizer ring made of an iron-based sintered alloy obtained by sintering is subjected to steam treatment or shot blast treatment and then to steam treatment (see Japanese Patent Application Laid-Open No. 8-177879).

[0003]

However, the conventional synchronizer ring made of an iron-based sintered alloy has a problem that Cu
Penetrates into the Fe powder boundary and lowers the bonding strength between Fe powders, so that it does not have sufficient strength, and therefore cannot respond to recent high performance, high load and light weight, There has been a demand for a synchronizer ring made of an iron-based sintered alloy having even higher strength, toughness and wear resistance.

[0004]

Means for Solving the Problems Accordingly, the present inventors have:
From the viewpoints described above, research was conducted to obtain a synchronizer ring made of an iron-based sintered alloy having higher strength, toughness, and wear resistance than in the past. (A) Cu: 15 to 40% by weight; Ni: 0.5 to 4.8
% By weight, C: 0.0005 to 0.85% by weight,
An iron-based sintered alloy synchronizer ring composed of an iron-based sintered alloy having a composition consisting of Fe and unavoidable impurities is a synchronizer made of an iron-based sintered alloy composed of a conventional iron-based sintered alloy. (B) In the synchronizer ring made of the iron-based sintered alloy described in (a), the Fe-based alloy phase is surrounded by the Cu-based alloy phase. Thereby forming a structure in which the Fe-based alloy phase and the Fe-based alloy phase are joined by the Cu-based alloy phase. (C) The Fe-based alloy containing Fe as a main component and constituting the base material of the iron-based sintered alloy The phase is an Fe alloy phase containing Ni, Cu and C and containing 50% by weight or more of Fe,
The Cu-based alloy phase containing u as a main component is a Cu alloy phase containing Ni, Fe and C and containing 50% by weight or more of Cu,
It has been found that the concentrations of Ni and C contained in the Fe-based alloy phase are more preferably higher than the concentrations of Ni and C contained in the Cu-based alloy phase.

The present invention has been made on the basis of the above findings. (1) Cu: 15 to 40% by weight, Ni: 0.5 to 4.8
% By weight, C: 0.0005 to 0.85% by weight,
The balance consisting of Fe and unavoidable impurities, and F
an e-based alloy phase surrounded by a Cu-based alloy phase;
The base alloy phase contains Ni, Cu and C and contains 50% by weight of Fe
The Fe-based alloy phase including the above, wherein the Cu-based alloy phase is N
Cu containing i, Fe and C and containing at least 50% by weight of Cu
The iron-based sintered alloy having a structure in which the concentration of Ni and C contained in the Fe-based alloy phase is higher than the concentration of Ni and C contained in the Cu-based alloy phase. A synchronizer ring made of a sintered alloy.

The synchronizer ring made of an iron-based sintered alloy according to the present invention is manufactured by mixing Fe powder, C powder and Cu-Ni alloy powder, compacting and sintering. However, when the C content contained in the synchronizer ring made of the iron-based sintered alloy of the present invention is extremely small,
It can be manufactured using C contained in Fe powder without adding powder.

The method for manufacturing the synchronizer ring made of the iron-based sintered alloy of the present invention will be described more specifically. Compound powder consisting of Fe powder and Cu-Ni alloy powder, or Fe
Powder, graphite powder and Cu-Ni alloy powder are prepared and mixed with a double cone mixer together with zinc stearate powder or ethylene bisstearamide, which is a lubricant at the time of molding, and press molding. To produce a green compact, and the green compact is placed in a nitrogen atmosphere containing hydrogen at a temperature of 1090 to 1300 ° C. (preferably 1100 ° C.).
〜1250 ° C.).

The mechanism for sintering the synchronizer ring made of the iron-based sintered alloy of the present invention is considered to be as follows. That is, in the initial stage of sintering, C
When the temperature is raised to the solid solution coexistence region of the u-Ni alloy, the appearance of a liquid phase improves the adhesion between Fe and the Cu-Ni alloy. At this time, since the generation of the liquid phase is partial, the sintered body does not undergo deformation such as distortion and bending. Fe and Cu-N
When the adhesiveness of the i-alloy improves, the N-
i diffuses into the Fe powder, and in the later stage of sintering, Cu
-Ni content in the Ni alloy powder diffuses into the Fe powder, so that the Ni content of the Cu-Ni alloy powder decreases to lower the melting point, the Cu-Ni alloy powder melts at a stretch, and a large amount of liquid phase is generated. Dynamic liquid phase sintering proceeds, and as a result, the sintered body is densified. Since the densification of the sintered body in the latter stage of sintering is performed after the adhesion is improved, the sintered body does not deform. Furthermore, during sintering, the Cu alloy liquid phase also penetrates into the grain boundaries in the Fe powder and divides the Fe powder at the grain boundaries, resulting in the formation of a fine Fe-based alloy phase mainly composed of Fe, A structure in which the fine Fe-based alloy phase is bonded with a Cu-based alloy phase containing Cu as a main component is formed, and the strength, toughness and wear resistance are improved. As described above, Ni of the Cu-Ni alloy powder diffuses into the Fe powder,
The amount of Ni contained in the Fe-based alloy phase is larger than the amount of Ni contained in the Cu-based alloy phase. At this time, C contained in the Fe powder or added C also diffuses into the Cu-Ni alloy powder, and Ni and A Cu-based alloy phase containing Cu containing C as a main component is generated. In the initial stage of sintering, Cu-Ni
Even if the temperature is not raised to the solid solution coexistence region of the alloy, Ni
e of the Cu—Ni alloy powder
As the i content decreases, the melting point decreases, and sintering proceeds to some extent by the same mechanism as described above.

The sintering of the iron-based sintered alloy synchronizer ring of the present invention is considered to be due to the mechanism as described above, and is used when manufacturing the iron-based sintered alloy synchronizer ring of the present invention. As raw material powder,
In particular, a Cu-Ni alloy (Ni: containing 2 to 50% by weight,
It is one of the important constitutions to use a powder of a mother alloy whose balance is composed of Cu and unavoidable impurities. Further, C
It is an element necessary to reduce Fe powder and Cu-Ni alloy powder and improve strength and hardness. However, if a large amount of C contained in Fe powder deteriorates Cu wettability, Cu alloy This prevents the liquid phase from penetrating into the Fe powder grain boundaries, and makes it impossible to obtain a fine Fe-based alloy phase. Therefore, the addition of C powder must be suppressed to 0.85% or less of the whole.

The iron-based sintered alloy synchronizer ring according to the present invention described in the above (1) has a density of 7.0 to 8.2 Mg.
/ M ³ . Therefore, the present invention provides: (2) a synchronizer ring made of an iron-based sintered alloy according to the above (1), which has a density of 7.0 to 8.2 Mg / m ³ ;
It is characterized by the following.

The synchronizer ring made of the iron-based sintered alloy described in the above (1) and (2) is preferably subjected to a steam treatment or a shot blast treatment and then to a steam treatment. Therefore, the present invention provides: (3) a synchronizer ring made of an iron-based sintered alloy obtained by performing a steam treatment on the synchronizer ring made of an iron-based sintered alloy according to the above (1) or (2); (1) A synchronizer ring made of an iron-based sintered alloy obtained by subjecting the synchronizer ring made of an iron-based sintered alloy described in (1) and (2) to a shot blast treatment and then to a steam treatment.

Next, the reason why the component composition of the synchronizer ring made of the iron-based sintered alloy of the present invention is limited as described above will be described. (A) Cu Cu has an effect of improving density, strength and abrasion resistance and further improving thermal conductivity.
When the amount is less than 40% by weight, the effect is not sufficient. On the other hand, when the amount exceeds 40% by weight, the liquid phase becomes excessively large, and deformation is caused during sintering, which leads to large dimensional variation and reduced strength. Therefore, the content of Cu is 15 to
It was determined to be 40% by weight. A more preferable range of the Cu content is 20 to 35% by weight.

(B) Ni Ni has the effect of increasing the melting point of the Cu alloy phase in the Cu alloy phase, controlling the liquid phase sintering, and improving the strength and toughness of the Fe alloy phase. If the amount is less than 0.5% by weight, the effect is not sufficient, while
Even if the content exceeds 4.8% by weight, no further effect is obtained. Therefore, the content of Ni is 0.5 to 4.8% by weight.
Determined. A more preferable range of the Ni content is 1 to 4% by weight.

(C) C C has the effect of reducing Fe powder and Cu-Ni alloy powder and improving the strength and hardness, but the effect is insufficient when the content is less than 0.0005% by weight. On the other hand, on the other hand, it is not preferable because the toughness contained in excess of 0.85% by weight is reduced. Therefore, the content of C is 0.00
It was determined to be 0.5 to 0.85% by weight. A more preferable range of the content of C is 0.001 to 0.3% by weight.

[0015]

EXAMPLES Example 1 Fe powder having an average particle size of 55 μm was used as a raw material powder.
Cu-Ni having the average particle size and component composition shown in
Alloy powders A to D and graphite powder having an average particle size of 18 μm were prepared.

[0016]

[Table 1]

These raw material powders are blended so as to have the composition shown in Tables 2 and 3, and zinc stearate powder, which is a lubricant at the time of mold molding, is used in an amount corresponding to 0.8% by weight on an outer surface. Add, mix and press-mold to create an inner diameter of 6
A synchronizer ring-shaped green compact having a size of 5 mm and a thickness of 3.5 mm and having 36 chamfers was prepared.

[0018]

[Table 2]

[0019]

[Table 3]

The green compact is sintered in a mixed atmosphere of N ₂ -5% H ₂ at a temperature of 1120 ° C. for 20 minutes and then cooled at a cooling rate of 0.5 ° C./sec Synchronizer rings made of the iron-based sintered alloy of the present invention (hereinafter, referred to as the rings of the present invention) 1 to 11 having the component compositions shown in Tables 4 to 5 and synchronizer rings made of a comparative iron-based sintered alloy (hereinafter, referred to as comparative examples) (Referred to as rings) 1 to 5 were produced. Further, a Cu powder is prepared, a Cu powder, a graphite powder, and an Fe powder are blended so as to have a blending composition shown in Table 3, mixed, and then sintered. A gold synchronizer ring (hereinafter, referred to as a conventional ring) was manufactured.

Further, a taper cone made of JIS SCM21 steel (carburized and quenched steel) is prepared, and using this taper cone under the following conditions, the wear resistance of the rings 1 to 11 of the present invention, the comparative rings 1 to 5 and the conventional ring is obtained. A test was conducted to measure the amount of wear (fall) and the coefficient of kinetic friction of the inner surface of the ring, and the results are shown in Tables 4 and 5.

Test conditions Rotation speed of taper cone: 1800 rpm, pressing load: 60 kg, oil type: No. 70 gear oil, oil temperature: 80 ° C., operation of taper cone: 2000 rpm with synchronization time of 0.5 to 0.7 seconds ,

Further, the contents of the Fe-based alloy phase and the Cu-based alloy phase in the structures of the rings 1 to 11 of the present invention were determined by EP.
As a result of measurement by MA, the Fe-based alloy phase was Ni, C
u and C and at least 50% by weight of Fe, and the Cu-based alloy phase contains Ni, Fe and C and contains 5% of Cu.
0% by weight or more and further contained in the Fe-based alloy phase
It was confirmed that the concentrations of C and C were higher than the concentrations of Ni and C contained in the Cu-based alloy phase.

Further, in order to evaluate the strength of the synchronizer ring, the raw material powder was blended so as to have the blending composition shown in Tables 2 and 3, and further, zinc stearate powder as a lubricant at the time of molding was used. Was added in an amount equivalent to 0.8% by weight on the outside, mixed and press-molded to obtain 30 mm ×
A green compact in the shape of a bending test specimen having a size of 12 mm × 6 mm was prepared, and this green compact was sintered in a mixed atmosphere of N ₂ -5% H ₂ at a temperature of 1150 ° C. and holding for 20 minutes. Thereafter, by cooling at a cooling rate of 0.5 ° C./sec, a bending test specimen made of an iron-based sintered alloy having the same composition as the rings 1 to 11 of the present invention, the comparative rings 1 to 5 and the conventional ring, and a Charpy impact. Test pieces were prepared respectively. Using the above-mentioned bending test piece, a bending force was measured by performing a bending test at a distance between fulcrums of 25 mm based on ISO3325, and further using a Charpy impact test piece, the JISZ22
The Charpy impact value was measured without a notch according to No. 42, and the results are shown in Tables 4 and 5.

[0025]

[Table 4]

[0026]

[Table 5]

From the results shown in Tables 4 and 5, when the rings 1 to 11 of the present invention are compared with the conventional rings, the rings 1 to 11 of the present invention have a smaller amount of wear and a larger dynamic friction coefficient than the conventional rings. From the results, it can be seen that the steel has excellent abrasion resistance, and that the transverse rupture strength and the Charpy impact value show high values, indicating that it has excellent strength and toughness. However, it can be seen that Comparative Rings 1 to 5 having a component composition outside the range of the present invention are inferior in at least one of the wear amount, the dynamic friction coefficient, the transverse rupture force, and the Charpy impact value.

Example 2 The ring 1 of the present invention was obtained by holding the rings 1 to 11 of the present invention obtained in Example 1 in steam at 500 ° C. for 60 minutes.
The rings 12 to 22 of the present invention were produced by performing a steam treatment for forming a triiron tetroxide film on the surfaces of Nos. 1 to 11, and a wear resistance test was performed on the rings 12 to 22 of the present invention under the same conditions as in Example 1. As a result, the wear amount of the present rings 12 to 22 was 80 to 90% of the present rings 1 to 11.

Example 3 After subjecting the rings 1 to 11 of the present invention obtained in Example 1 to a shot blasting treatment, the rings 1 to 11 of the present invention were further subjected to a steaming treatment for 60 minutes in steam at 500 ° C. 33, and the rings 23-3 of the present invention were prepared.
As a result of performing a wear resistance test on Sample No. 3 under the same conditions as in Example 1, the wear amounts of the rings 23 to 33 of the present invention were found to be equal to the rings 1 to 11 of the present invention.
70-80%.

[0030]

As described above, the synchronizer ring made of an iron-based sintered alloy of the present invention has a small amount of wear, a large coefficient of kinetic friction, and a high transverse rupture force and a high Charpy impact value. Can also provide excellent iron-based sintered alloy synchronizer rings, which can greatly contribute to the development of the automobile industry.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-60-165307 (JP, A) JP-A-3-47944 (JP, A) JP-A-5-271879 (JP, A) JP-A-5-271879 306433 (JP, A) JP-A-59-38354 (JP, A) JP-A-8-177879 (JP, A) JP-A-10-47379 (JP, A) JP-A-10-73132 (JP, A) JP-B-45-18567 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C22C 38/00 304 B22F 5/12 C22C 33/02 C22C 38/16 F16D 23/05

Claims (4)

(57) [Claims] 1. Cu: 15 to 40% by weight, Ni: 0.5
4.8 % by weight, C: 0.0005 to 0.85% by weight, the balance being Fe and unavoidable impurities,
And that the Fe-based alloy phase is surrounded by the Cu-based alloy phase.
And the Fe-based alloy phase is bonded by a Cu-based alloy phase.
F containing Ni, Cu and C and containing 50% by weight or more of Fe
e-based alloy phase, wherein the Cu-based alloy phase is Ni, Fe and
Alloy phase containing at least 50% by weight of Cu
Of Ni and C contained in the Fe-based alloy phase
Is higher than the concentrations of Ni and C contained in the Cu-based alloy phase.
Be composed of an iron-based sintered alloy with a large structure
Synchronizer ring made of iron-based sintered alloy . 2. The synchronizer ring made of an iron-based sintered alloy according to claim 1 , wherein the synchronizer ring has a density of 7.0 to 8.2 Mg / m ³ . 3. An iron-based sintered alloy according to claim 1 or 2.
The synchronizer ring must be steamed.
Synchronizer phosphorus made of iron-based sintered alloy
G 4. The iron-based sintered alloy according to claim 1 or 2
Synchronizer ring shot blasted
Iron-based firing characterized by being subjected to steam treatment after
Synchronizer ring made of bonded gold .