JPS63227746A - Fe sintered alloy synchronizing ring for transmission - Google Patents

Abstract

PURPOSE:To furthermore improve the strength, wear resistance and conformability by specifying the constituent and porosity of a synchronizing ring and the thickness of a nitriding layer. CONSTITUTION:The synchronizing ring consists of, by weight, 0.1-0.9% C, 0.2-8% Cu and/or Ni, 0.02-0.5% B and the balance Fe, has 0.05-5vol.% porosity and contains the nitriding layer having 3-200mu average layer thickness at least on a taper cone friction face 1. In this synchronizing ring, any characteristics among at least the strength, wear resistance and conformability are deteriorated when any requirements of the constitutional requirements are deviated from the above-mentioned areas. Since the titled ring has the high strength, excellent wear resistance and conformability with the objective members, it can sufficiently correspond to the high outputting, thinning accompanied by light weight and miniaturization of a transmission.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a synchronizing ring for a transmission made of an Fe-based sintered alloy that has high strength, excellent wear resistance, and compatibility with a mating member. be.

[Conventional technology]

Conventionally, a synchronizing ring for a transmission generally has an inner surface 1 which is in intermittent surface contact with a rotating tapered cone under high surface pressure, and an outer peripheral surface 1, as illustrated in a perspective view in FIG.
Since the chamfers 2 provided at predetermined intervals along the outer edge have the function of engaging with the chamfers of the hub sleeve, they are required to have strength, wear resistance, and compatibility with the mating member. High-strength brass with these characteristics is often used in In addition, there is also a so-called pin type synchronizing ring, which has a thread on the outer circumferential side and rubs against the mating tapered cone on the outer circumferential side.

[Problem that the invention seeks to solve]

However, in recent years, there have been strict demands for higher output and lighter weight for transmissions, and as a result, synchronizer rings are also required to have even higher levels of strength, wear resistance, and conformability. However, the current situation is that conventional high-strength brass products cannot adequately meet this requirement.

[Means for solving problems]

Therefore, the present inventors conducted research to develop a synchronizing ring for transmissions that can fully meet the above requirements, and as a result, the results are expressed in weight percent (hereinafter).

Regarding component composition, C indicates weight %), C: O, 1 to 0
．． 9%, one or two of Cu and Ni, 0.2 to 8%, B: 0.02 to 0.5%, the remainder being Fe and unavoidable impurities, and 0.2 to 8% of Cu and Ni. A transmission made of an Fe-based sintered alloy, in which a nitrided layer is formed at least on the tapered cone friction surface of an Fe-based sintered alloy body having a porosity of 05 to 5 i: H, with an average layer thickness of 3 to 200 μm. It was discovered that the synchronizing ring has high strength, excellent wear resistance, and compatibility with mating parts, and is therefore fully compatible with increasing the output and reducing the weight of transmissions.

Next, in the synchronous ring of the present invention, the reason why the component composition, porosity, and average layer thickness of the nitrided layer are limited as described above will be explained.

(a) CC The C component has the effect of improving strength and wear resistance, but if the content is less than 0.11, the desired effect cannot be obtained; on the other hand, if the content is less than 0.9 %, the toughness decreases and cracks are more likely to occur due to impact, and the aggressiveness towards opponents also increases.

(b) Ni and Cu These components have the effect of improving strength, abrasion resistance, and conformability, but if their content is less than 0.2%, the desired effect of improving the above effects is not seen. On the other hand, even if the content exceeds 8%, no further improvement effect can be obtained, so the content was set at 02 to 8%.

(c) B The B component has the effect of improving toughness and strength in addition to improving sinterability, but if its content is less than 0.02%, the desired effect of improving the above effects cannot be obtained, On the other hand, if the content exceeds 0.5%, the toughness decreases, so the content was set at 0.02 to 0.5%.

In addition, although Si, S, and P components are contained as unavoidable impurities, if the total amount of these components exceeds 0.5%, the strength and toughness will decrease, so The content must be limited to 0.5 inch or less.

B, porosity The pores in the alloy become oil reservoirs during practical use.

In particular, it improves the initial conformability of the inner surface of the ring, suppresses its temperature rise, and prevents adhesive wear. It also promotes the penetration of the nitrided layer and increases its thickness, thereby improving wear resistance. It has the effect of normalizing wear by forming a thin oxide film on the surface of the pores, but if the ratio is less than 0.05 capacitance, the desired effect cannot be obtained; If the amount exceeds 5, the strength will decrease and it will become impossible to put it to practical use, so the ratio is set at 0.05.
It was set at ~5%.

Average layer thickness of the C0 nitride layer If the average layer thickness is less than 3 μm, the desired excellent wear resistance cannot be ensured over a long period of time, while if the average layer thickness exceeds 200 μm, the toughness tends to decrease. Therefore, the average layer thickness was determined to be 3 to 200 μm.

〔Example〕

Next, the synchronization ring of the present invention will be specifically explained using examples.

Graphite powder, Cu powder, Ni powder, RE powder, and Fe-B alloy (B: 15% content) powder, all of which have a particle size of 200 mesh or less, were prepared as raw material powders, and these raw material powders were After blending with the composition shown in the table and mixing under normal conditions, 5.5tOn/c
After press-forming into green compacts at a pressure of rIL2 and pre-sintering these green compacts at a predetermined temperature within the range of 700 to 900°C, a part of these pre-sintered bodies was warmly heated for 6 to 90 minutes. 8 tons/
The pre-sintered body and the re-pressed pre-sintered body are treated with ammonia. In cracked gas,
Sintering is performed at a predetermined temperature within the range of 1000 to 1200°C for 1 hour to form a sintered body having substantially the same composition as the blended composition, and furthermore, a part of these sintered bodies is are hot forged at a temperature within the range of 800 to 1000℃, and the presence or absence of hot forging is indicated in the remarks column of Table 1), and as a result, the various porosity shown in Table 1 are obtained. , inventive sintered rings 1 to 5, and 7 to 13, and comparative sintered rings 1 to 6. After immersing at the specified temperature for 10 minutes to 5 hours,
The sintered ring 6 of the present invention is subjected to oil-cooled nitriding treatment in oil at a predetermined temperature within the range of 0°C to form a nitrided layer with the average layer thickness shown in Table 1 only on the inner surface. For comparative sintered ring 7, in an ammonia atmosphere, 520 to 60
By performing gas nitrocarburizing treatment under the condition of holding the temperature within the range of 0℃ for 3 hours, it has the shape shown in Fig. 1, the dimensions of inner diameter = 58 mm φ x thickness 28 mm, and the number of outer chamfers. : 32 synchronous rings for transmissions made of Fe-based sintered alloy of the present invention (hereinafter referred to as sintered rings of the present invention) 1 to 13 and comparative synchronous rings for transmissions made of Fe-based sintered alloy (hereinafter referred to as comparative sintered rings) 1 to 7 were manufactured, respectively.

In addition, Comparative Sintered Rings 1 to 7 have any of the conditions (those marked with * in Table 1) of the component composition, porosity, and average layer thickness of the nitrided layer that are outside the scope of this invention. It's out of place.

Next, regarding the various sintered rings obtained as a result,
The transverse rupture strength was measured for the purpose of evaluating the strength, and the number of rotations of the tapered cone, which was the mating material: 11000r-
p-,.

Material of the taper cone: 80M21 carburized and quenched material, Pressing load: 90 Yu, Oil: No. 80 mission oil, Oil temperature: 90℃, Taper cone operating mode: Press for 1 second and pull away for 2 seconds.

Cycle: 7000 cycles.

Single unit wear test under the following conditions: Rotation speed of the taper cone: 1200 r, pm, Pressure load of the taper cone: 50 Yu, Material of the mating material of the taper cone and knob sleeve: SCM-21 carburized and quenched material , synchronization time 20.3 seconds to 0.4 seconds (number of times: 50,000 times).

Oil: No. 90 transmission oil, oil temperature near 0℃, bench test was conducted under the following conditions.In the former single wear test, the presence or absence of cracks in the ring, and the friction surface of the ring's chi-goo cone (hereinafter referred to as the inner surface) were conducted. Maximum amount of wear, maximum amount of wear of the mating material (the maximum amount of wear mentioned above was expressed by the amount of fall measured by preparing a standard product for measuring the amount of fall), presence or absence of seizure on the inner surface of the ring, ring The initial (up to 500 cycles) and late (stable period) friction coefficients of the inner surface and the presence or absence of initial wear on the inner surface of the ring were observed.In the latter bench test, the presence or absence of abnormal wear of the chamfer and abnormal noise during synchronization were observed. The presence or absence of each was measured. These results are shown in Table 2.

〔Effect of the invention〕

From the results shown in Table 2, the sintered rings 1 to 13 of the present invention
Comparative sintered rings 1 to 7 all have high strength and excellent wear resistance and conformability.
As seen in the above, it is clear that if any of the constituent features falls outside the scope of the present invention, at least one of the above characteristics will be inferior.

It goes without saying that similar results can be obtained with a pin-type synchronous ring.

As mentioned above, the synchronizing ring for a transmission made of Fe-based sintered alloy of the present invention has high strength, excellent wear resistance, and compatibility with mating parts, so it can increase the output and reduce the weight of the transmission. This makes it possible to satisfactorily cope with the thinner walls and smaller sizes that accompany this.

[Brief explanation of the drawing]

FIG. 1 is a perspective view illustrating a synchronizing ring for a transmission. 1... Tapered cone friction surface (inner surface), 2... Chamfer.

Claims (1)

[Claims] C: 0.1 to 0.9%, one or two of Cu and Ni: 0.2 to 8%
, B: 0.02 to 0.5%, with the remainder consisting of Fe and unavoidable impurities (volume %), and a porosity of 0.05 to 5 volume %. A synchronizing ring for a transmission made of an Fe-based sintered alloy, comprising a nitrided layer formed on at least the tapered cone friction surface of the main body with an average layer thickness of 3 to 200 μm.