JP2000055132A - Flywheel damper supporting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flywheel damper supporting structure which has less dimensional change of a bearing raceway ring and less drop of hardness even in a high-temp. environment, has good heat resistance of grease, and has excellent resistance against fretting and a long lifetime. SOLUTION: A transmission side mass 3 and an engine side mass 2 are mutually supported by a rolling bearing 6, in which a grease using urea as thickener is encapsulated. The inner 11 and outer rings 12 are made of steel, whose residual austenite content should be 8% or less and hardness be over HRC60. The amount of grease encapsulation should be 40-50% of the intra- bearing space. The grease uses a synthetic oil as its base oil, and the thickener should be aromatic urea. A seal 15 is made of fluororubber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a flywheel damper support structure for supporting a flywheel damper of an automobile engine with rolling bearings.

[0002]

2. Description of the Related Art A flywheel damper divides a flywheel into an engine-side mass and a transmission-side mass, and a compression spring and a damping mechanism are provided therebetween. It is used to reduce the vibration noise related to the torsional vibration of the drive shaft system. Rolling bearings that mutually support the engine-side mass and the transmission-side mass of the flywheel damper transmit vibration from the engine,
Since the outer ring is used in an environment in which the outer ring co-rotates and swings, there is an environment in which fretting wear is likely to occur.

[0003] With the recent high performance and miniaturization of automobile engines, the operating environment of the bearings has become more and more severe.
It is necessary to assume use in a high temperature environment exceeding ℃.
Due to such high temperatures in the operating environment, the bearings used to support flywheel dampers are subject to changes in bearing dimensions, a reduction in the hardness of races, and a decrease in lubricity due to thermal deterioration of grease.
There is a concern that fretting wear will occur, and it is expected that the seizure life will be shortened. Also, measures must be taken against grease leakage due to changes in seal dimensions due to high temperatures.

It is an object of the present invention to provide a long-life flywheel damper support structure which has little dimensional change and hardness reduction of a bearing race even under a high temperature environment, has good heat resistance of grease, and has excellent fretting resistance. To provide. Another object of the present invention is to improve lubricity by grease, and to improve fretting resistance and seizure resistance. Another object of the present invention is to prevent grease leakage in a high-temperature environment due to insufficient heat resistance and compression set of the seal.

[0005]

A flywheel damper support structure according to the present invention is a flywheel damper support structure in which a transmission-side mass and an engine-side mass of a flywheel damper are supported by rolling bearings each other. Is to seal grease containing urea as a thickener, and at least the inner and outer races that are attached to the engine side mass are made of steel, have a residual austenite amount of 8% or less, and have a hardness of HRC 60 or higher. The raceway made of the above material may be either the inner race or the outer race, or both. Increasing the amount of retained austenite in the bearing ring increases the hardness and is preferable for preventing wear. However, when used in a high-temperature environment such as a recent engine, the dimensional stability over time is reduced. On the other hand, due to advances in steelmaking technology, the hardness of HRC 60 or more required to prevent fretting wear is secured even if the amount of retained austenite is 8% or less by appropriately setting the chemical composition of the steel used as the material and the heat treatment temperature. It is possible to do. Therefore, the present invention
Thus, the amount of retained austenite is suppressed to the extent that the required hardness can be ensured, and dimensional stability over time in a high-temperature environment ("high-temperature environment" means a temperature environment of 150 ° C or higher in this specification) is secured. By doing so, the occurrence of fretting wear due to an excessive gap is prevented. Fretting wear is likely to occur on bearing rings mounted on the engine-side mass among bearing races. Therefore, at least the material and hardness of the bearing ring mounted on the engine-side mass are set as described above. Fretting wear can be prevented for both races. Also, by using a grease containing urea as a thickener, the heat resistance of the grease is obtained, and the fretting wear resistance is further improved.

In the present invention, the amount of grease charged is
Preferably, it is set to 40 to 50% of the space in the bearing. The amount of grease enclosed is generally 25 to 30%. By increasing the amount of enclosed grease in this way, lubricity is improved, fretting resistance is improved, and seizure resistance is improved.

Further, in the present invention, it is preferable to use a grease in which the base oil is synthetic oil and the thickener urea is aromatic urea. Synthetic oil is excellent in fretting resistance and heat resistance, and among ureas, aromatic urea is particularly excellent in heat resistance. For this reason, the use of synthetic oil as base oil and aromatic urea as urea thickener further improves the heat resistance of grease, and improves the fretting resistance and seizure resistance of raceway rings. I do.

Further, in the present invention, it is preferable that the rolling bearing is sealed with a fluorine rubber sealing material. Fluororubber has excellent heat resistance and compression set resistance. Therefore, by using a fluororubber sealing material, the change in the seal diameter is reduced, and the sealing performance is improved.
For this reason, the occurrence of fretting caused by a decrease in lubricity due to grease leakage is prevented.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The upper half of FIG. 1A shows an AO cross section of FIG. 2, and the lower half of FIG.
The O section is shown. This flywheel damper support structure
The flywheel 1 is divided into an engine-side mass 2 and a transmission-side mass 3 and a compression spring 4 and a damping mechanism 5 are provided therebetween. Are mutually supported by bearings 6. As the bearing 6, a rolling bearing is used so that damping is performed smoothly. Output torque from the engine enters from an engine-side mass 2 directly connected to a crankshaft (not shown), and is transmitted to a driven system via a compression spring 4, a damping mechanism 5, and a transmission-side mass 3. In this case, depending on the magnitude of the output torque of the engine, the flexure of the compression spring 4 and the damping mechanism 5
In this state, the torque fluctuation is absorbed by the compression spring 4 and the damping mechanism 5, so that the transmission-side mass 3 rotates with respect to the engine-side mass 2 with the attenuated rotation fluctuation amount. The damping mechanism 5 is formed by an oil chamber 5 a, and rotation transmission between the two masses 2 and 3 via the compression spring 4 and the damping mechanism 5 is performed via a driven plate 7. The driven plate 7 is connected to the transmission-side mass 3 by serrations 8 provided on the inner diameter portion. Projection 7a provided on the outer diameter of driven plate 7
A stopper 9 is provided on the engine-side mass 2 in correspondence with the above.

The bearing 6 comprises a sealed deep groove ball bearing shown in FIG. 1 (B). A rolling element 14 such as a steel ball held by a retainer 13 is interposed between an inner ring 11 and an outer ring 12, and is provided on both sides. Is provided with a seal 15. The seal 15 is obtained by integrating a rubber body 15b having a lip portion 15c with a core metal 15a, and an outer diameter edge is fitted into a seal mounting groove 16 formed on an inner diameter surface of the outer ring 12, and the inner diameter edge is formed. Is in sliding contact with the outer surface of the inner race 11 or the inner surface of the seal groove 17 provided in the outer surface.

The mounting of the bearing 6 on the two masses 2 and 3 is performed as follows. The inner ring 11 is fitted on an outer diameter surface of a cylindrical portion 2 a formed on an inner diameter portion of the engine-side mass 2, and
8 prevents it from falling off. The outer ring 12 is fitted on the inner diameter surface of the cylindrical portion 3a formed on the inner diameter portion of the transmission-side mass 3, and is prevented from falling off by a retaining ring 19 fitted into a retaining ring groove formed on this inner diameter surface.

The bearing 6 has the following construction in detail. The inner ring 11 as a raceway ring attached to the engine side mass 2 of the bearing 6 and the outer ring 12 as a raceway ring attached to the transmission side mass 3 are made of the following materials. That is, the inner ring 11 and the outer ring 12 are, by weight ratio, 0.95 to 1.10% of carbon, 1-2% of silicon or aluminum, 1.15% or less of manganese, and 0.9% of chromium.
Steel made of 0 to 1.60% with the balance being iron and impurities and having an oxygen content of 13 ppm or less is used as a material, and after quenching of a product formed from the material, 180 ° C to 400 ° C (preferably 230 ° C to 300 ° C). , More preferably 250
Tempering at a high temperature (° C. to 280 ° C.) to reduce retained austenite to 8% or less and hardness to HRC 60 or more. In the case where the thickness of the product is large, it is preferable to add molybdenum (Mo) to the above material to improve the hardenability. The amount of molybdenum added is set to 0.25% by weight or less, preferably 0.10 to 0.25% by weight.

The reason why the oxygen content is set to 13 ppm or less is that from the test result of non-metallic inclusions, if the oxygen content is 13 ppm or less, large non-metallic inclusions are hardly observed on the fracture surface, and therefore, the residual austenite This is because the effect on the rolling life can be reduced. Also, S
The reason why i and Al are set to 1 to 2% by weight is that when 1% by weight or less of Si or Al is added, the hardness at the time of high-temperature tempering becomes small, and when 2% by weight or more, toughness is not preferable in view of toughness. This is because a problem arises in the workability of cutting and grinding. Further, the high temperature tempering temperature is preferably 230 ° C.
To 300 ° C., more preferably 250 ° C. to 280 ° C., but the residual austenite in the 230 ° C. tempered product is determined to be 8% in the test results of the test piece, and therefore, the amount of retained austenite is 8% or less, preferably 6%. % Or less.

The rubber member 15b in the seal 15 of the bearing 6
Is preferably made of fluoro rubber.

The grease to be filled in the bearing 6 uses urea as a thickener. Among ureas, it is preferable to use an aromatic urea because of excellent heat resistance. The base oil is a mineral oil or a synthetic oil, but it is preferable to use a synthetic oil. Among synthetic oils, ether oils are preferred because of their excellent heat resistance. The amount of grease enclosed is preferably 40 to 50% of the volume of the inner space of the bearing. The volume of the grease internal space is a space obtained by subtracting the volumes of the rolling elements 14 and the retainer 13 from the space surrounded by the inner and outer rings 11 and 12 and the seals 15 and 15 on both sides.

According to the flywheel damper support structure of this construction, the inner ring 11 and the outer ring 12 of the bearing 6 are made of steel, the amount of retained austenite is 8% or less, and the hardness is HRC 60 or more. Dimensional change in a high temperature environment is less than that in the case of using bearing steel (for example, SUJ2 material of JIC standard), and the occurrence of fretting due to an excessively large or small gap can be prevented.
In addition, the decrease in hardness in a high-temperature environment is small, and the fretting resistance is improved. In particular, the above-mentioned carbon, silicon or aluminum, manganese, chromium, the balance of iron and impurities and the like described in the description section of this embodiment, and the steel of the oxygen content as a material, formed by the material After the quenching of the product, tempering is performed at the above temperature to reduce the retained austenite to 8% or less and the hardness is HRC60.
In the case of the above, the above effects are remarkably obtained.

Further, since the seal 15 is made of a fluoro rubber, the heat resistance and the compression set resistance are superior to those of a conventional acrylic rubber used for the seal. The dimensional change of the diameter is small, and the sealing performance of the outer diameter portion of the seal 15 is improved. When grease uses urea as a thickener and synthetic oil as a base oil, the synthetic oil has excellent fretting resistance and heat resistance.
The heat resistance of grease is improved, and the seizure resistance of the bearing is improved. As described above, when aromatic urea having excellent heat resistance among ureas is used as the thickener and ether oil having excellent heat resistance among synthetic oils is used as the base oil, the heat resistance is further improved. Furthermore, since the amount of grease is 40 to 50%, and the amount of grease is increased as compared with the conventional general amount of 25 to 30%, lubricity is improved, and both fretting resistance and seizure resistance are improved. improves. The combination of the materials of the inner and outer rings 11 and 12, the material of the seal 15, the material of the grease, and the increase in the amount of the grease enclosed,
Even in a high temperature environment, a long-life flywheel damper support structure with little dimensional change and hardness decrease of the bearing race ring, good grease heat resistance, and excellent fretting and seizure resistance can be effectively realized. .

Table 1 below shows test results of fretting occurrence and seizure resistance when the amount of retained austenite, hardness, and grease component of the inner and outer rings 11 and 12 are variously changed. 2 shows the results of comparison.
Aromatic urea was used as urea as a grease thickener, and ether was used as synthetic oil. The amount of grease
It was set to 40 to 50%. ◎ 、
○, × were evaluated in three stages.

[0019]

[Table 1]

From the above Table 1, the race was made of steel, had a retained austenite content of 8% or less, and had a hardness of H.
It can be seen that the case of RC60 or more is excellent in fretting resistance. Further, it can be seen that the use of a synthetic oil as the base oil of grease is superior in seizure resistance.

The following Table 2 shows test results comparing the fretting resistance and the seizure resistance when the amount of grease is 25% to 35% and when the amount of grease is 40% to 50%. . The grease used was a urea thickener and a mineral oil base oil. From the results in the table,
For all of the examples, the amount of grease enclosed is 40 to
It can be seen that the case of 50% is more excellent in fretting resistance and seizure resistance.

[0022]

[Table 2]

[0023]

According to the flywheel damper support structure of the present invention, a grease containing urea as a thickener is filled in a rolling bearing for mutually supporting a transmission side mass and an engine side mass. At least the race attached to the engine side mass is made of steel,
Retained austenite content is 8% or less and hardness is HRC
Since it is 60 or more, even in a high-temperature environment, there is little dimensional change and hardness decrease of the bearing race, and there is little thermal deterioration of the grease, and a long life with excellent fretting resistance is obtained. Increase the amount of grease
When it is set to 50%, the lubricating property is improved by increasing the amount of grease enclosed, the fretting resistance is further improved, and the seizure resistance is also improved. When the base oil used is synthetic oil as the base oil and the urea as the thickener is an aromatic urea, the heat resistance of the grease is good, and the fretting resistance and seizure resistance are further improved. When the seal material of the rolling bearing is a seal material made of fluoro rubber, heat resistance and compression set resistance are excellent, so the change in seal diameter is small, the sealability is improved, and the lubricity is reduced due to grease leakage. Fretting is prevented from occurring.

[Brief description of the drawings]

FIG. 1A is a sectional view of a flywheel damper support structure according to an embodiment of the present invention, and FIG. 1B is an enlarged sectional view of a bearing thereof.

FIG. 2 is a cutaway front view of the flywheel damper support structure.

[Explanation of symbols]

 2 ... Engine side mass 3 ... Transmission side mass 4 ... Compression spring 5 ... Damping mechanism 6 ... Bearing 11 ... Inner ring (track ring attached to engine side mass) 12 ... Outer ring 15 ... Seal

Claims (4)

[Claims] 1. A flywheel damper supporting structure in which a transmission-side mass and an engine-side mass of a flywheel damper are mutually supported by rolling bearings, wherein the rolling bearing encloses grease containing urea as a thickener, A flywheel damper support structure in which at least one of the inner and outer races attached to the engine side mass is made of steel, has a residual austenite amount of 8% or less, and has a hardness of HRC60 or more. 2. The flywheel damper support structure according to claim 1, wherein the amount of the grease to be filled is 40 to 50% of the inner space of the bearing. 3. The flywheel damper support structure according to claim 1, wherein said grease is made of synthetic oil as base oil and aromatic urea as urea as a thickener. 4. The flywheel damper support structure according to claim 1, wherein the rolling bearing is sealed with a fluoro rubber seal.