JPS63293321A - Vibration-proof bearing used in vibrational circumstance - Google Patents

Abstract

PURPOSE:To reduce the vibration and noise by making at least an inner ring, an outer ring, or a roller with a martensite type stainless steel which consists of Cr 12 to 18 wt% and C 0.6 to 1.0 wt%. CONSTITUTION:A bearing 11 consists of an inner ring 12, an outer ring 13, a conical roller 14, and a holder 15. At least for one of the inner ring 12, the outer ring 13, and the conical roller 14, preferably for both the inner ring 12 and the outer ring 13, a martensite type stainless steel which consists of Cr 12 to 18 wt% and C 0.6 to 1.0 wt% is used.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a vibration damping bearing used in a vibration environment, and more particularly to a vibration damping bearing used in a gear device such as an automobile transmission.

Conventional technology and its problems In gear devices, vibrations and noise caused by gear meshing errors are transmitted to the case through the bearings that support the gears, and are often radiated to the outside, causing problems.

For example, in recent years, transmissions for automobiles and other vehicles have been made by die-casting from aluminum alloys to reduce weight, and aluminum alloys have high vibration transmission properties.
Since it does not have vibration damping properties, there is a problem in that vibration and noise are largely dissipated to the outside. In addition, there are increasing demands for higher rotation speeds and quieter environments, and there is an increasing need to reduce the above-mentioned vibrations and noise.

As a general vibration damping method, between the bearing outer ring and the housing,
At least one place between the bearing inner ring and the shaft or between the gear and the shaft is coated with a polymer material such as silicone rubber
It is known to be effective to install a liner made of a highly damping material such as a damping alloy such as a -Mn alloy or a 12% Cr-Fe alloy.

However, this method has the following problems. That is, when the liner is attached to the outer ring of the bearing, the area around the bearing becomes larger. When a liner is attached to a bearing inner ring or a gear, the bearing or gear becomes larger or the shaft diameter becomes smaller, resulting in a decrease in shaft strength. Furthermore, in either case, the number of parts and assembly man-hours increase, resulting in increased costs and decreased accuracy.

Another known damping method is to make the gears and bearing inner rings themselves from damping alloys.

However, this method has the following problems. In other words, gears and bearings used in automobile transmissions are subjected to high loads with a contact surface pressure of 200 kgf/a+a+2 or more, so in order to withstand that load and not cause impressions or to ensure a long rolling life. Harden and temper high carbon chromium bearing steel (SUJ2, etc.), or carburize and temper alloy case hardened steel for machine structures (SCr420, etc.) to achieve surface hardness of HRC58.
or tensile strength of approximately 200 kgf/a+m
2, it is designed to provide sufficient strength. In contrast, conventional damping alloys have the highest strength, 12
Even %Cr-Fe alloy has low strength, with a hardness of about HRB80 (HRC cannot be converted) and a tensile strength of about 50 kg 1/1112, so it cannot be used for gears and bearings in transmissions of automobiles.

An object of the present invention is to solve the above problems and provide a vibration damping bearing that does not require a separate vibration damping member such as a liner and can be used in a highly intense vibration environment.

Means for Solving the Problems The present inventors have focused on ferromagnetic type damping alloys, as they have the potential to improve strength among various types of damping alloys. It is known that the vibration damping ability of ferromagnetic vibration damping alloys decreases when the strain amplitude increases or when static stress is applied. In the problem, static stress is not a problem and the strain amplitude is small, so
The possibility of practical use was considered.

Assuming a Cr-Fe alloy as a ferromagnetic vibration damping alloy, the inventors completed this invention as a result of repeated studies on the content of Cr and C in order to provide the vibration damping effect and strength necessary for bearing parts. .

That is, in the vibration-damping bearing according to the present invention used in a vibration environment, at least one of the inner ring, outer ring, or rolling element contains 12 to 18% by weight of C and 0.6 to 1.0% by weight. It is made of a certain martensitic stainless steel.

The reasons for setting Cr and C within the above ranges are as follows. If the Cr content is less than 12%, the damping effect will not be sufficient;
If it exceeds 18%, giant carbides are formed. Also, C is 0.6
If it is less than 1.0%, the hardness will be insufficient, and if it is more than 1.0%, not only will it be ineffective, but also giant carbides will be formed.

Functions and Effects of the Invention In the vibration damping bearing used in a vibration environment according to the present invention, at least one of the inner ring, the outer ring, and the rolling elements has a C content of 12 to 18% by weight and a C content of 0°6 to 1.0% by weight. % martensitic stainless steel, it has a high vibration damping effect and high strength.Therefore, by using a bearing to which this invention is applied, vibration and noise can be reduced without reducing strength or transfer durability. Moreover, there is no need to separately provide a damping member such as a liner.

Therefore, the number of parts does not increase, the bearing and its surroundings do not increase in size, and the shaft strength does not decrease.

Examples Next, examples of the present invention will be illustrated in order to demonstrate the above effects.

FIG. 1 shows an example in which the present invention is applied to a tapered roller bearing (11) that supports an intermediate shaft (lO) of an automatic transmission of an automobile.

This bearing (11) consists of an inner ring (12), an outer ring (13), tapered rollers (14), and a cage (15). Inner circle (
12) is fitted onto the outer periphery of the boss portion (1θa) of the gear (1B) fixed to the shaft (10). Outer ring (13
) is fitted onto the inner periphery of the bearing support cylinder portion (1B) of the transmission case (17). At least one of the inner ring (12), outer ring (13), and rollers (14) of the bearing (11), preferably the inner ring (12) and the outer ring (13)
12 to 18% by weight of C and 0.6 to 1°0 of C.
% martensitic stainless steel is used.

In order to confirm the effects of this invention, we examined a current conical rolling bearing (comparative example) whose inner and outer rings are made of carburized steel (SAE5120) and an inner and outer ring made of Co, 68%, Cr1.
A tapered roller bearing of the same type (Example) was made of martensitic stainless steel containing 3% SLo, 31% Mn, 0.69% Mn, the balance Fe and unavoidable impurities.

First, the shaft was passed through a cylindrical experimental case fixed on a stand, and an auxiliary bearing similar to the comparative example was installed between one end of the case and the shaft. The comparative example and the example were replaced and installed on the holder, and the shaft was rotated by a motor.

Then, axial and radial vibration pickups were attached to the steel housing part that received the outer ring of the comparative example or example, and the steel sleeve provided between the inner ring and the shaft of the comparative example or example was moved in the radial direction using an impulse hammer. The ratio of the output vibration at the outer ring housing portion transmitted through the comparative example or the example to the input vibration at this time was measured as a transfer function.

The results are shown in FIG. The figure shows that the preload of the comparative example and the example was 16 kgf-cm, and the shaft rotation speed was 1000 r.
This relates to axial vibration when pa+.

From the results shown in Figure 2, in the case of the example, compared to the comparative example, it is found that approximately 1
A maximum attenuation effect of 6 dB was observed over the frequency range of ~4 KHz.

Next, the comparative example and the example were replaced and installed on the driven gear side of the intermediate shaft of an actual automatic transmission of a 200 OCC class passenger car, and the other bearings were left as they were and the vehicle was operated.

Then, a vibration pickup was attached to the transmission case, and the vibration level transmitted to the nearby transmission case via the comparative example or the example was measured.

The results are shown in FIG. In the same figure (a), the input torque is 18
．． At the time of acceleration of 0 kg-m, the input torque is -3,
The results are shown when decelerating at 0 kg-a+.

From the results shown in Figure 3, the frequency range of 1 to 3 KHz (vehicle speed of 30 to 9 KHz) is annoying to drivers as gear noise.
In the frequently used speed range of 0.01 v/h), in the case of the example, a maximum attenuation effect of about 10 dB was observed compared to the comparative example, especially during deceleration.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view of the main part of a tapered roller bearing showing one embodiment of the present invention, Fig. 2 is a graph showing test results using models of a comparative example and an example, and Fig. 3 is also based on an actual machine. It is a graph showing test results. (11)...Tapered roller bearing, (12)...Inner ring, (
13)...Outer ring, (14)...Roller. Patent applicant: Koyo Seiko Co., Ltd. Figure 1

Claims (1)

[Claims] At least one of the inner ring, outer ring, or rolling element is made of Cr.
A vibration damping bearing used in a vibration environment, made of martensitic stainless steel containing 12 to 18% by weight of C and 0.6 to 1.0% by weight of C.