JPH116521A - Roller bearing and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the coefficient of friction of the surface of a bearing part, and to prevent generation of the seizure even when the lubricating condition is bad by forming a sulphurized layer on at least one bearing part of a bearing ring and a rolling element. SOLUTION: In a shell type needle roller bearing having a shell 1 which is an outer ring of approximately cylindrical shape, a plurality of rollers 2 in contact with an inner circumferential surface of the shell 1, and a holder 3 to hold the rollers 2, the rollers 2 are brought into direct contact with the outer circumference of a shaft 4. A sulphurized layer is formed on the surface of the outer ring 1 and the rollers 2 through the heat treatment in the atmospheric gas containing hydrogen sulfide and nitrogen, and the sulphurized layer plays a role of the solid lubrication. Even when the outer ring 1 and the roller 2 are formed of either high carbon chromium bearing steel, case-hardened steel, carbon steel for mechanical structure, and stainless steel, the coefficient of friction of the surface can be reduced by achieving the nitrosulphurizing treatment, and the seizure is prevented from being easily generated even when the lubricating condition is bad.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing and a method of manufacturing the same, and more particularly to a rolling bearing made of bearing steel and the like and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, bearing components of rolling bearings made of bearing steel or the like have generally been subjected to coreless quenching, carburizing quenching or carbonitriding quenching to thereby obtain bearing components. Abrasion resistance and long life have been achieved.

However, recent bearing applications tend to be lubricated, and rolling bearing components are required to improve seizure resistance, wear resistance and service life in such a bad environment. Improvement is required.

Accordingly, an object of the present invention is to provide a rolling bearing having excellent seizure resistance and wear resistance and a long service life even in a bad environment such as under dilute lubrication, and a method of manufacturing the same. .

[0005]

According to the present invention, there is provided a rolling bearing comprising:
In a rolling bearing having a bearing ring and a rolling element, a sulfurized layer is formed on at least one bearing component of the bearing ring and the rolling element.

In the rolling bearing of the present invention, since the sulfur layer is formed on at least one bearing component between the race and the rolling element, the friction coefficient of the surface of the bearing component can be reduced, and the lubrication conditions are poor. Also, seizure hardly occurs, and as a result, a long life can be obtained.

A rolling bearing according to the present invention is a rolling bearing having a bearing ring, a rolling element, and a retainer for holding the rolling elements, wherein at least one bearing component of the bearing ring, the rolling element and the retainer is used. It is characterized in that a sulfurized layer is formed.

[0008] In the rolling bearing of the present invention, since the sulfurized layer is formed on at least one bearing component of the race, the rolling element and the cage, the friction coefficient of the surface of the bearing component can be reduced, and the lubrication condition can be reduced. However, even if it is poor, seizure hardly occurs, and as a result, a long life can be obtained.

Preferably, in the above aspect, the surface hardness of the sulfurized layer is HRC 57 or more. Thereby, the hardness required for the bearing is obtained.

[0010] In the above aspect, preferably, the sulfur layer contains nitrogen. By including nitrogen as described above, the surface hardness can be increased.

[0011] In the above aspect, preferably, the sulfurized layer is formed on the surface of the bearing component. Thereby, the effect of solid lubrication can be obtained on the surfaces of the race and the rolling elements.

Preferably, in the above aspect, the bearing ring on which the sulfur layer is formed is a pressed product made of a steel plate. That is, it can be effectively applied to products such as steel plate pressed products.

Preferably, in the above aspect, the race, the rolling element or the cage is made of at least one steel material selected from the group consisting of high carbon chromium bearing steel, case hardening steel, carbon steel for machine structural use, and stainless steel. Has become. By selecting the material in this way, it is possible to obtain a rolling bearing that has a low surface friction coefficient and is less likely to seize even under poor lubrication conditions.

Preferably, in the above aspect, when the rolling bearing is mounted on the shaft and the housing, the rolling element has a configuration capable of directly contacting either the outer peripheral surface of the shaft or the inner peripheral surface of the housing. By forming a sulfurized layer on the surface of the rolling element, even when used for such an application, it is excellent in wear resistance and seizure resistance, and as a result, a long life can be obtained.

Preferably, in the above aspect, a cage for holding the rolling elements is further provided, and a sulfurized layer is formed on the surface of the cage. This makes it possible to obtain a cage having a low coefficient of friction on the surface and hardly causing seizure even under poor lubrication conditions.

According to a method of manufacturing a rolling bearing of the present invention, in a method of manufacturing a rolling bearing having a race and a rolling element, at least one bearing component of the race and the rolling element is subjected to a heat treatment in an atmosphere containing sulfur. And forming a sulfurized layer.

As a result, a rolling bearing having excellent wear resistance and seizure resistance and having a long life can be manufactured.

According to a method of manufacturing a rolling bearing of the present invention, there is provided a method of manufacturing a rolling bearing having a bearing ring, a rolling element, and a retainer for holding the rolling elements. It is characterized in that one bearing component is subjected to a heat treatment in an atmosphere containing sulfur to form a sulfurized layer.

Thus, a rolling bearing having excellent wear resistance and seizure resistance and having a long service life can be manufactured.

[0020]

Embodiments of the present invention will be described below.

The inventor of the present application conducted the following experiment in order to examine the effect of forming a sulfur layer. First, a shell-type needle roller bearing shown in FIG. 1 was prepared. Here, this shell-type needle roller bearing comprises a shell 1 which is an outer ring having a substantially cylindrical shape, and a plurality of rollers 2 which are in contact with the inner peripheral surface of the shell 1.
And a holder 3 for holding the rollers 2. In this shell type needle roller bearing, the roller 2 is configured to directly contact the outer periphery of the shaft 4.

The outer ring 1, roller 2 and cage 3 of the shell type needle roller bearing having the configuration shown in FIG.
The materials formed with the materials, the depths of the sulfurized layers, and the surface hardness shown in Table 1 were used as examples of the present invention. In addition, a shell type needle roller bearing shown in FIG. 1 in which the outer ring 1 and the rollers 2 are formed with the materials, depths and surface hardnesses of the sulfur layers shown in Table 2 below, except for a cage, is a conventional example. .

[0023]

[Table 1]

[0024]

[Table 2]

It was also confirmed that the surfaces of the outer ring 1 and the rollers 2 contained nitrogen.

Here, each member of the outer ring 1, the rollers 2 and the cage 3 constituting the shell-type needle roller bearing of the present invention was obtained through the heat treatment conditions shown in Table 3. In other words, the outer ring 1 is operated in a gas atmosphere containing 2% butane, 3 to 5% ammonia, and 0.02% hydrogen sulfide in Rx gas.
After holding at a temperature of 0 ° C. for 90 minutes, quenching was performed from a temperature of 850 ° C. Roller 2 contains 0.5% butane, 3-5% ammonia and 0.02% in Rx gas.
9 at a temperature of 900 ° C under a gas atmosphere containing hydrogen sulfide
After holding for 0 minutes, quenching was performed at a temperature of 850 ° C. The cage 3 was not subjected to the heat treatment.

[0027]

[Table 3]

The outer race 1 and the rollers 2 constituting the conventional shell-type needle roller bearing were obtained through the heat treatment conditions shown in Table 4. That is, the outer ring 1 was prepared by holding at a temperature of 880 ° C. for 60 minutes in a gas atmosphere containing 2% butane in Rx gas and then quenching from a temperature of 840 ° C. The roller 2 was prepared by holding at a temperature of 840 ° C. for 30 minutes in an Rx gas atmosphere and then quenching from a temperature of 840 ° C.

[0029]

[Table 4]

The thus obtained shell type needle roller bearings of the present invention and the conventional example were subjected to a transfer fatigue life test under test conditions 1 and 2 shown in Table 5 below. The time until the starting type failure and the time until the peeling damage occurred were measured. The results are shown in Table 6 below.
Shown in

[0031]

[Table 5]

[0032]

[Table 6]

Table 6 shows the ratio of each life of the example of the present invention when the rolling fatigue life and the peeling life of the conventional example are each set to 1. As evident from this result,
It was found that the example of the present invention can provide a longer life than the conventional example under the test condition 1 with relatively good lubrication conditions and the test condition 2 with relatively poor lubrication conditions. In addition, it has been found that, in the example of the present invention, especially under the test condition 2 where the lubricating condition is poor, a much longer life can be obtained than in the conventional example.

According to the present invention, a heat treatment is performed in an atmosphere gas containing hydrogen sulfide to form a sulfur layer on the surfaces of the outer ring 1 and the rollers 2, and the sulfur layer plays a role of solid lubrication. It is considered that this was done. Further, as shown in Table 1, even when the sulfurized layer was formed, the surface hardness required for the rolling bearing was obtained because nitrogen was contained in the atmosphere gas together with hydrogen sulfide. It is considered that this was effectively taken into the surface of the roller 1 or the roller 2.

Even if the outer race 1 and the rollers 2 are made of any of high carbon chromium bearing steel, case hardening steel, carbon steel for machine structure use and stainless steel, the sulphinitriding treatment is performed as described above. It was also confirmed that the application reduced the coefficient of friction of the surface and made it difficult for seizure to occur even under poor lubrication conditions, resulting in a long life.

In this embodiment, the shell type needle roller bearing including the outer ring 1, the rollers 2 and the cage 3 has been described. However, the cage 3 may not be provided, and the inner ring may be further provided. Alternatively, only the inner ring without the outer ring 1 may be used. When the needle roller bearing is constituted by the inner ring portion 2 without the outer ring 1, the roller 2 comes into direct contact with the inner peripheral surface of the housing when the bearing is mounted.

In the present embodiment, the shell type needle roller bearing has been described. However, the present invention is applicable not only to this bearing but also to other rolling bearings such as a deep groove ball bearing.

Further, in this embodiment, the cage 3 is not subjected to the nitrosulphurizing treatment, but the cage 3 may be subjected to the nitrosulphidizing treatment. In this case, the coefficient of friction of the surface is low,
In addition, it is possible to obtain the cage 3 in which seizure hardly occurs even when lubrication conditions are poor.

In this embodiment, the case where the needle roller bearing is subjected to the nitrosulphurizing treatment has been described. It can also be applied to

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0041]

According to the rolling bearing of the present invention, since the sulfur layer is formed on at least one bearing component between the race and the rolling element, the friction coefficient of the surface can be reduced, and even if the lubrication conditions are poor. Seizure hardly occurs, and as a result, a long life can be obtained.

Further, in the method for manufacturing a rolling bearing of the present invention,
At least one bearing component of the bearing ring and the rolling element is subjected to a heat treatment in an atmosphere containing sulfur to form a sulfurized layer, so that the surface has a low coefficient of friction and seizure hardly occurs even under poor lubrication conditions. As a result, a long-life rolling bearing can be manufactured.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a configuration of a shell-type needle roller bearing.

[Explanation of symbols]

 1 outer ring (shell) 2 roller 3 cage 4 axis

Claims (10)

[Claims] 1. A rolling bearing comprising a bearing ring and a rolling element, wherein a sulfurized layer is formed on at least one bearing component of the bearing ring and the rolling element. 2. A rolling bearing having a bearing ring, a rolling element, and a retainer for holding the rolling elements, wherein at least one bearing component of the bearing ring, the rolling element and the retainer has a sulfur layer. A rolling bearing, characterized in that a rolling bearing is formed. 3. The rolling bearing according to claim 1, wherein the surface hardness of the sulfurized layer is HRC 57 or more. 4. The rolling bearing according to claim 1, wherein the sulfurized layer contains nitrogen. 5. The rolling bearing according to claim 1, wherein the sulfurized layer is formed on a surface of the bearing component. 6. The rolling bearing according to claim 1, wherein the bearing ring on which the sulfur layer is formed is a pressed product made of a steel plate. 7. The bearing ring, the rolling element or the cage is made of at least one steel material selected from the group consisting of high carbon chromium bearing steel, case hardening steel, carbon steel for machine structural use, and stainless steel. The rolling bearing according to claim 1, wherein the rolling bearing is provided. 8. When the rolling bearing is mounted on a shaft and a housing, the rolling element has a configuration capable of directly contacting either the outer peripheral surface of the shaft or the inner peripheral surface of the housing. The rolling bearing according to claim 1 or 2, characterized in that: 9. A method for manufacturing a rolling bearing having a bearing ring and a rolling element, wherein at least one bearing component of the bearing ring and the rolling element is subjected to a heat treatment in an atmosphere containing sulfur to form a sulfurized layer. Forming a rolling bearing. 10. A method for manufacturing a rolling bearing having a bearing ring, a rolling element, and a retainer for holding the rolling elements, wherein at least one of the bearing ring, the rolling element, and the retainer is provided.
A method for producing a rolling bearing, comprising subjecting two bearing parts to heat treatment in an atmosphere containing sulfur to form a sulfurized layer.