JPH094652A - Synchronizer ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synchronizer ring excellent in the inertial property and scuffing property by executing the steam process or the blast process and steam process to the inner peripheral surface which synchronously slides over at least a rotating opponent member and disengages from the opponent member. SOLUTION: Fine irregularities and numerous empty holes exist in the inner peripheral surface 101 of a sybchronizer ring made of a sintered body having 8-15μmRz of surface roughness. When the inner peripheral surface is subjected to the steam process at 550 deg.C-600 deg.C for 30-90min., a Fe304 coating having numerous empty holes of about 1μm of inner diameter is formed on the irregularity part of the surface to provide 20-25μmRz of surface roughness and about 500 of hardness. Thus, since the inner peripheral surface 101 has the increased surface roughness, an oil film formed on the contact surface between the inner peripheral surface and the opponent member is thinned. As a result, the boundary lubricating condition is apt to take place and maintained so that though the coefficient of friction is heightened, the scuffing is prevented by the oiling effect of oil included in the empty holes in the Fe304 coating.

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 Fe-based sintered alloy, and more particularly, to a synchronizer ring having excellent friction characteristics and scuffing resistance, which is easy to process and has a stable quality. About.

[0002]

2. Description of the Related Art For example, in a synchronous mesh type gear transmission, a synchronizer ring has been conventionally used. This synchronizer ring is a friction ring that performs synchronous sliding with a rotating counterpart member, for example, a tapered cone, and separates from the tapered cone, and is important for making the peripheral speeds of two gears meshing with each other constant. Make a great move. As the structure, as shown in FIG. 1, a plurality of tooth profiles 100 meshing with a mating member are provided at predetermined intervals on an outermost peripheral portion, and a longitudinal groove 103 is formed on an inner peripheral surface 101 which comes into contact with the tapered cone. It is known that a ring-shaped groove 102 is formed so as to be orthogonal to the vertical groove 103 as needed, and a key groove 104 into which a synchronizer key is fitted is provided on the outer peripheral surface. Therefore, brass (Cu-Zn alloy) was generally used as a material for forming the same.

For example, a synchronizer ring which may be formed in such a structure generally has not only high mechanical strength and accuracy but also excellent frictional characteristics of an inner peripheral surface which comes into contact with a mating member. It is required to have sufficient scuffing resistance. Especially in the field of automobile transmissions, friction characteristics of the inner peripheral surface are required because not only reliable operability but also high-quality operation and sporty feeling are required in response to higher-grade and higher-performance missions in recent years. And a synchronizer ring with improved scuffing resistance is desired.

[0004] In view of the above, various types of synchronizer rings have been studied which have improved friction characteristics and scuffing resistance on the inner peripheral surface as compared with conventional synchronizer rings using brass (Cu-Zn alloy) as a forming material. . Specifically, a synchronizer ring (Japanese Patent Publication No. 46-1) in which a metal, a ceramic, and an oxide are uniformly mixed and a layer fused to each other is formed on the inner peripheral surface by a thermal spraying method.
No. 5043). As a method that can be used for manufacturing a synchronizer ring, for example, a friction lining made of a sintered powder containing 80% by weight of a metal component powder and 20% by weight of a non-metal component powder is applied to the inner peripheral surface by a flame injection method. A method for producing a friction ring to be formed is also known (DE 3705661).

Further, a synchronizer ring made of an Fe-based sintered alloy containing bainite, pearlite and a free Cu phase as a base structure has been studied.

[0006]

However, a metal, ceramics and oxide are uniformly mixed and a layer fused to each other is formed on the inner peripheral surface by a thermal spraying method or a metal component powder of 80% by weight. A conventional synchronizer such as one obtained by adopting a method of manufacturing a friction ring in which a friction lining made of a sintered powder containing 20% by weight of a non-metal component powder and a non-metal component powder is formed on an inner peripheral surface by a flame injection method. Rings have not yet achieved the required frictional properties and scuffing resistance. In addition, there is also a problem that the strength is insufficient due to insufficient diffusion of each metal component, and the quality becomes unstable due to a variation in the material of the thermal spray coating. In addition, the surface layer of the sprayed coating often includes incompletely melted particles in the frame or scattered / bounced particles, and the like. In addition, there is a problem in that the transmission system tends to change easily, and abrasion of various parts of the transmission system occurs due to the detachment of the attached particles. On the other hand, grinding or cutting was also performed on the surface of the sprayed film for the purpose of reducing the surface roughness of the sprayed film,
When such grinding or cutting is performed, there is a disadvantage in that processing costs are increased and raw materials are wasted in a margin for the grinding or cutting.

Further, in a synchronizer ring made of an Fe-based sintered alloy containing bainite and pearlite and a free Cu phase in a base structure, the hardness is as high as about HRB 90 or more because bainite is included, and sizing is difficult. However, there is still room for improvement in the dynamic friction coefficient. The present invention has been made based on the above circumstances, and an object of the present invention is to provide a synchronizer ring which is excellent in friction characteristics and scuffing resistance and has stable quality.

[0008]

In order to achieve the above-mentioned object, the means adopted by the present invention is a synchronizer ring made of a Fe-based sintered alloy, which is at least a synchronous sliding member with a rotating mating member and a mating member. This is because the inner peripheral surface to be separated from is subjected to steam treatment or blast treatment and steam treatment.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Graphite powder, Cu powder and Fe powder, each having a particle size of usually 150 mesh or less, are blended at a predetermined ratio and mixed under normal conditions, and then 4.5 to 6.5 t.
A green compact may be formed by applying pressure at a pressure of about on / cm 2 and sintering the green compact at a temperature of about 1000 to 1200 ° C.

[0010] The inner peripheral surface of the synchronizer ring made of the sintered body has fine irregularities and numerous holes.
Its surface roughness is 8 to 15 μm Rz. When this inner peripheral surface is subjected to steam treatment at 550 ° C. to 600 ° C. for 30 to 90 minutes, the surface irregularities have numerous pores with an inner diameter of about 1 μm.
e3 O4 film is formed and the surface roughness is 20-25μ
The hardness of mRz is about Hv500.

As described above, since the inner peripheral surface of the synchronizer ring has an increased surface roughness, the oil film formed on the inner peripheral surface in contact with the mating member becomes thinner. As a result, boundary lubrication (metal contact) is likely to occur and is maintained, so the coefficient of friction is high, but scuffing is prevented by the effect of the oil contained in the pores in the Fe3 O4 coating. To be done.

If not only steam treatment but also blast treatment and steam treatment are applied to the inner peripheral surface, the oil film is easily broken and a passage for removing oil is secured, so that the inner peripheral surface and the mating member are easily lubricated at the boundary. State. Further, by blasting the inner peripheral surface, the tips of the convex portions of the inner peripheral surface layer are likely to elastically deform, which increases the true contact area between the inner peripheral surface and the outer peripheral surface of the mating member, Further increases the frictional force between the peripheral surface and the mating member.

A synchronizer ring made of an Fe-based sintered alloy has fine holes, but in the synchronizer ring, it is necessary to apply a frictional force to an inner peripheral surface particularly in contact with a tapered cone which is a mating member. Further, it must have scuffing resistance. here,
From the viewpoint of scuffing resistance, it is preferable that the porosity is small, and from the viewpoint of frictional characteristics, the porosity is large. From such a viewpoint, in the synchronizer ring of the present invention,
The porosity of at least the inner peripheral surface is preferably in the range of 2% by volume to 12% by volume. If the porosity is less than 2% by volume, the frictional force on the inner peripheral surface that contacts the tapered cone, which is a mating member, may not be sufficient. On the other hand, when the porosity exceeds 12% by volume, the strength of the synchronizer ring tends to decrease and the scuffing resistance tends to decrease. The surface roughness is preferably in the range of 19 to 50 μmRz. Particularly preferred is 25 to 35 μm Rz
Is the range of. When the surface roughness is less than 19 μmRz, gear squeal occurs quickly when the value of the friction coefficient (μ) reaches the level of 0.08. Also, the surface roughness is 50
If it exceeds μmRz, the scuffing limit surface pressure is lowered, and the scuffing resistance is deteriorated.

[0014]

Next, the present invention will be described specifically with reference to examples. Example 1 As raw material powders, graphite powder, Cu powder, Fe-W powder and Fe powder (low alloy steel powder) each having a particle size of 150 mesh or less were prepared, and these raw material powders were graphite powder 0.9 ( wt%), Cu powder 10 (wt%), Fe-W
Powder 10 (wt%) and the remainder of the Fe powder were mixed under ordinary conditions to obtain a mixed powder. Next, this mixed powder was preformed into a green compact under the condition of a pressure of 5 ton / cm ² . Then, this green compact was placed in an ammonia decomposition gas for 10 minutes.
By sintering at a temperature within the range of 00 to 1200 ° C. for 80 minutes, a sintered body having substantially the same components as the composition was obtained. From this sintered body, 4
Test pieces of Comparative Examples 1, Comparative Example 2, Example 1, and Example 2 were prepared. Comparative Example 1 is untreated, Comparative Example 2 is blasted, Example 1 is steam treated at 550 ° C. for 30 minutes, and Example 2 is steam treated and blasted at 550 ° C. for 30 minutes. It was done. The friction coefficient of each test piece was measured under the following conditions using a cylindrical-cylindrical plane contact type sliding friction type sliding friction tester as shown in FIG.

Pressing load: 80 kgf Sliding speed: 1 m / sec Lubricating oil used: SAE75W-90 Oil temperature: 90 ° C Lubrication method: Immersion Counterpart material: SCM420 Carburizing quenching and tempering (surface hardness Hv (0.1) 600) Hard S: Measured by Micro Vickers.

In the cylinder-cylindrical plane contact type sliding friction tester shown in FIG. 2, 10 is a rotary shaft, 11 is a mating material, 11a is a mating material sliding surface, 12 is a sintered material test piece, 12
a is a test piece sliding surface, and 13 is a fixed shaft. The measurement results are as shown in FIG. 3, and the friction coefficient is maximum in Example 2 in which blast treatment and steam treatment are performed, Example 2 in which steam treatment is performed is second, and Comparative Example 2 in which only blast treatment is performed. The third, untreated Comparative Example 1 is the smallest. In Example 2 and Comparative Example 2 where blasting was performed, the variation in the coefficient of friction was smaller than in Example 1 and Comparative Example 1 where blasting was not performed. Example 2 A sintered body was manufactured in the same manner as in the above Example, and the scuffing resistance of the obtained sintered body test piece was evaluated.

Each test piece was subjected to a scuffing test under the following conditions using the same tester as in the above-mentioned example, and the surface pressure when scuffing occurred at each sliding speed was measured as the limit surface pressure. Initially, the sliding speed was 1 m / sec, the initial load was 1
Set to 0 kgf and increase the load to 20 kgf after 5 minutes and run for 5 minutes.
Was measured by increasing the load at the rate of

Pressing load: Until scuffing occurs Sliding speed: 2 m / sec, 4 m / sec, 6 m / sec Lubricating oil used: SAE75W-90 Oil temperature: 90 ° C. Lubrication method: Immersion Counterpart material: Same as Example 1 4 is as shown in FIG. 4, and the scuffing resistance is Example 1 in which the rank 1 is the steam treatment, and Rank 2 is the embodiment 2 in which the blast treatment and the steam treatment are performed. Comparative Example 2 in which only the blasting treatment was performed and Comparative Example 1 in which no treatment was performed are equivalent in rank 3. Thus, the embodiment of the present invention subjected to the steam treatment is clearly superior in scuffing resistance.

Using the tester shown in FIG. 2, the arrival time to the friction coefficient (μ) = 0.08 level was measured under the same conditions as in Example 1. As a result, a surface roughness of 15 μm Rz
Comparative Example 3 has an arrival time of 13 hours and a surface roughness of 17 hours.
In Comparative Example 4 with μmRz, the arrival time was 14 hours and 30 minutes. In Example 3 having a surface roughness of 30 μmRz, the arrival time was 15
The coefficient of friction (μ) at the time was 0.13, and the coefficient of friction (μ) of Example 4 having a surface roughness of 35 μmRz at the time when the arrival time was 15 hours was also 0.13. It was found that the reduction rates of the friction coefficient (μ) of Examples 3 and 4 were smaller than those of Comparative Examples 3 and 4 and were excellent in durability.

Using the tester shown in FIG. 2, the scuffing resistance was evaluated under the same conditions as in Example 2.
Comparative Example 5 having a surface roughness of 55 μmRz has a scuffing limit surface pressure of 35 kgf / cm ^{2 which is} smaller than 40 kgf / cm ^2.
And surface roughness 3 after blasting and steaming
In Example 5 of 5 μmRz, the scuffing limit surface pressure is 45.
a kgf / cm ^2, which was subjected to only the water vapor treatment was 65 kgf / cm ^2. If the surface roughness is 50 μmRz or less, the scuffing limit surface pressure can be easily set to 40 kgf.
/ Cm ² or more can be maintained.

[0021]

As described above, according to the present invention, the friction characteristics are stable, the synchronism with the counterpart cone and the detachability are excellent, the scuffing resistance is excellent, and the spraying film is ground or cut. Is not required, and a synchronizer ring with stable quality can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a synchronizer ring.

FIG. 2 is an explanatory view showing an outline of a cylinder-to-cylinder plane contact type sliding friction tester used in Examples.

FIG. 3 is a graph showing a coefficient of friction measured by the tester shown in FIG. 2;

FIG. 4 is a graph showing a scuffing limit surface pressure measured by the tester of FIG. 2;

[Explanation of symbols]

 100: Tooth profile, 101: Inner sliding surface, 102: Ring-shaped groove, 103: Vertical groove, 104: Key groove

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Takao Omiya 1111 Nogi, Nogi-cho, Shimotsuga-gun, Tochigi Japan Piston Ring Co., Ltd. Tochigi factory (72) Inventor Shigemi Omura 1-shiroyama, Kojima-cho, Nishio-shi, Aichi Aisin AI Co., Ltd.

Claims (4)

[Claims] 1. A synchronizer ring made of an Fe-based sintered alloy, characterized in that at least an inner peripheral surface for performing synchronous sliding with a rotating mating member and separating from the mating member has been subjected to steam treatment. And synchronizer ring. 2. A synchronizer ring made of a Fe-based sintered alloy, wherein at least an inner peripheral surface for performing synchronous sliding with a rotating mating member and separating from the mating member is subjected to a blast treatment and a steam treatment. A synchronizer ring characterized by that. 3. The Fe-based sintered alloy is 2% by volume to 12% by volume.
The synchronizer ring according to claim 1 or 2, having a porosity of. 4. The roughness of the inner peripheral surface that performs at least synchronous sliding with the rotating mating member and disengages from the mating member is 19
The synchronizer ring according to any one of claims 1 to 3, wherein the synchronizer ring has a thickness of -50 mRz.