JP2002323055A - Bearing with seal and bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing with a seal which can keep fixation by press-in of a seal even when an interference to press-insert a track ring in a housing or an axis is large or the bearing is used under an environment of high humidity like accessories and the like of automobile. SOLUTION: This device is constituted so that it equips the seal 6 between an outer ring 3 and an inner ring 2 and this seal has core metal 6a which is fitted by press-in to the outer ring 3. The outer ring 3 is fixed by press-in to the housing 11 with a material like aluminium or the like which has a large coefficient of linear thermal expansion. The core metal 6 is the one treated so as to minimize an permanent deformation. Nitrocarburizing or other processes are used for this treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed bearing installed in an aluminum housing or the like and used in a high-temperature environment, for example, a sealed bearing used in an auxiliary machine of an automobile or the like. Regarding improvement.

[0002]

2. Description of the Related Art In an auxiliary machine of an automobile, for example, a fan clutch, a bearing is press-fitted into an aluminum housing and is sometimes used for rotating an outer ring. A bearing with a seal is used for the bearing to prevent dust and water from entering.
In such an installation mode, the periphery of the bearing is in a high temperature environment (for example, 150 ° C. or higher), and the amount of thermal expansion between the bearing outer ring made of bearing steel and the housing made of aluminum is significantly different. is there. For this reason,
A bearing having a plastic band for thermal expansion correction attached to the outer diameter surface of the bearing outer ring may be used. In the case of such a bearing with a plastic band, the tightness of the outer ring is loose, so that there is no problem with the sealability.

[0003]

However, if a plastic band is provided, the cost becomes high. In order to provide a cheaper bearing, the interference between the bearing and the aluminum housing is increased, and the amount of thermal expansion between the bearing and the housing is increased. Even if there is a difference, an attempt has been made to secure the interference during operation. If the interference between the bearing outer ring and the housing is increased, the plastic band can be omitted, so that the cost can be reduced. However, there is an unresolved problem with the installation of the seal.

[0004] As a seal in this type of bearing, an oil seal with a cored bar is generally used, and the cored bar is press-fitted into an outer ring for mounting. Usually, a cold rolled steel plate is used for the cored bar. However, when a core made of a cold-rolled steel plate is used, the interference between the bearing outer ring and the aluminum housing is 0.1%.
In the case of a large tightening allowance exceeding 00 mm, some permanent deformation may occur when the core of the seal shrinks with the shrinkage of the outer ring due to the fitting of the outer ring to the housing. If the above-mentioned permanent deformation occurs in the core metal, when the outer ring thermally expands during operation, it is difficult to secure the interference between the core metal and the outer ring, and the mounting of the seal may be incomplete. The above description is of the installation mode in which the outer ring is press-fitted into the housing. However, the same problem also occurs in the installation mode in which the inner ring is press-fitted on the shaft.

SUMMARY OF THE INVENTION An object of the present invention is to provide a bearing with a seal capable of maintaining a fixed state by press-fitting a seal even when a bearing ring is press-fitted into a housing or a shaft with a large pressurization and used in a high temperature environment. It is to provide a bearing device.

[0006]

In the bearing with seal of the present invention, a seal for sealing an annular space between these races is provided between an outer race and an inner race, which serves as an inner race. In a sealed bearing having a core bar mounted by press-fitting on the race, the core bar is subjected to a process of reducing permanent deformation. According to this configuration, since the core of the seal is subjected to a process of reducing permanent deformation, when the race is tightly fitted to the housing or the shaft, the interference is large, and the diameter of the race is small. Even if the change is large, permanent deformation of the core of the seal is avoided. Therefore, even when the bearing ring is used in a high-temperature environment and the thermal expansion of the bearing ring is large, the press-fit state of the seal core is maintained. As described above, this bearing with a seal has a large interference for press-fitting the bearing ring into the housing or the shaft, and can maintain a fixed state by press-fitting the seal even when used in a high-temperature environment.

[0007] The seal may be one in which a core is attached to the inner surface of the outer ring by press fitting. When the seal is mounted on the inner surface of the outer ring, the interference of press fitting of the seal core into the outer ring is loosened due to thermal expansion of the outer ring due to a high temperature environment during operation of the bearing. However, since the seal core is processed to reduce permanent deformation, the seal core is prevented from being permanently deformed when the outer ring is pressed into the housing. Therefore, the outer ring of the seal core during thermal expansion of the outer ring is prevented. , The press-fit state of the seal core is maintained.

In the case of a bearing for press-fitting the seal core into the outer ring, the outer ring may be made of steel, and the outer ring may be fixed to the aluminum housing by press-fitting. When the outer race is made of steel and the housing is made of aluminum, the difference in the amount of thermal expansion is large. Therefore, in such a case, the effect of maintaining the press-fitting of the seal by the process of reducing the permanent deformation of the seal core is effective.

The treatment for reducing the permanent deformation may be a nitrocarburizing treatment. According to the soft nitriding treatment, the property of reducing the permanent deformation of the core metal can be effectively obtained.

In the sealed bearing according to the present invention, the interference between the outer race and the housing to which the outer race is fixed by press fitting may be 0.100 mm or more. When the interference is set to 0.100 mm or more, even if the housing is made of a material having a larger linear expansion coefficient than the outer ring, at a certain high temperature, the interference of the outer ring to the housing is not lost, and the outer ring is fixed. Is maintained. For example, even if the outer race is made of steel and the housing is made of aluminum, in the case of a bearing having a normal diameter, even if the temperature becomes 150 ° C. or higher, the interference remains. Even if the interference between the outer ring and the housing is as large as 0.100 mm or more, the seal core is treated to reduce permanent deformation. Permanent deformation of the core is prevented. Therefore, when the inner diameter is increased due to the thermal expansion of the outer ring, the press-fit state of the seal core is maintained, and detachment of the seal is prevented.

According to the bearing device of the present invention, a seal for sealing an annular space between the races is provided between the inner race and the outer race, which serves as an outer race and an inner race. In a sealed bearing having a core to be attached, it is assumed that the core has been subjected to a process of reducing permanent deformation.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In this bearing 1 with a seal, a rolling element 5 held by a retainer 4 is interposed between an inner ring 2 and an outer ring 3, which are race rings, to form an annular ring between the inner and outer rings 2, 3. Seals 6 for sealing the space are provided on both sides of the annular space. The rolling element 5 is made of a ball, and this bearing with a seal is a deep groove ball bearing. The inner and outer rings 2 and 3 and the rolling elements 5 are made of bearing steel. The seal 6 has a cored bar 6a.
And an elastic body 6b made of rubber or synthetic resin. The seal 6 is attached to the outer ring 3 by press-fitting the core metal 6 a into the inner diameter surface of the outer ring 3, and the elastic body 6 b slides on the outer diameter surface of the inner ring 1. The core metal 6 a has a cylindrical outer diameter portion 6 aa press-fit into the outer ring 3, and a seal mounting surface portion 3 formed as a stepped large diameter portion at both ends of the inner diameter surface of the outer ring 3.
a.

The metal core 6a of the seal 6 is made of metal such as steel which has been subjected to a treatment for reducing permanent deformation. Core 6
The material a is preferably a steel material that has been subjected to a soft nitriding treatment as a treatment for reducing the above-mentioned permanent deformation. As the steel material, low carbon steel or the like is used, and a steel plate such as a cold-rolled steel plate is used.

The nitrocarburizing treatment is one of the surface strengthening methods.
The nitriding method is classified into gas nitriding, salt bath nitrocarburizing, salt nitrocarburizing, and ion nitriding. The latter three methods are collectively referred to as nitrocarburizing, which has wear resistance by diffusing nitrogen or nitrogen and carbon,
It is defined as a heat treatment that improves fatigue resistance. For the nitrocarburizing treatment in this embodiment, any of the above three methods of salt bath nitrocarburizing, salt nitrocarburizing, and ion nitriding may be used. At present, the gas nitrocarburizing method is mainly used as the nitrocarburizing method, and various treatment methods have been developed and put into practical use. For example, there are a nitrogen-based nitrocarburizing method, an oxynitriding method, a sulfur-nitriding method, a vacuum nitrocarburizing method, and the like, and these methods can be adopted in this embodiment. The nitrocarburizing treatment has the advantage that, in addition to the above-mentioned improvement in wear resistance and fatigue resistance, the distortion of the heat treatment is small and the softening resistance of the hardened layer is large, so that it is possible to cope with an increase in the component surface temperature. can get.

[0015] The soft nitriding treatment is used as a surface strengthening method. However, when compressed, it has a characteristic that when compressed, the elastic limit is high and permanent deformation hardly occurs. In this embodiment, a soft nitriding treatment is used for the core 6a of the seal 6 in view of the property that permanent deformation hardly occurs.

A bearing device using the sealed bearing 1 will be described. This bearing 1 with a seal comprises a housing 1
The outer race 3 is fixed to the inner diameter surface of the base 1 by press-fitting, and is used for rotation of the outer race. The housing 11 is made of a material having a larger linear expansion coefficient than that of the outer ring 3, and is made of, for example, aluminum. The interference of the outer ring 3 with respect to the housing 11 is, for example, at a high temperature of 150 ° C. or more and at a size such that the interference of the outer ring 3 with respect to the housing 11 does not disappear. At room temperature, (interference) / (outer ring outer diameter) ≧ 0.001 It is said. Therefore, in a bearing having a normal diameter, the interference is set to 0.100 mm or more. The housing 11 is, for example, a rotating component that constitutes an auxiliary machine of an automobile.

According to this configuration, since the core 6a of the seal 6 has been subjected to the process of reducing permanent deformation,
When the outer ring 3 is tightly fitted to the housing 11, even if the interference is large and the diameter of the outer ring 3 greatly changes,
Permanent deformation of the core 6a of the seal 6 is avoided.
For example, when the housing 11 is made of aluminum and the outer ring 3 is made of bearing steel, the interference at normal temperature is set so that the interference of the outer ring 3 is not lost under a high temperature environment (150 ° C. or higher) during operation. (Tightening) / (outer ring outer diameter) ≧ 0.001,
It becomes 0.001 mm or more. Even in the case of such a large interference, if the core metal 6a is soft-nitrided, the core metal 6a may be permanently deformed with respect to the reduction of the inner diameter of the outer ring 3 at the time of press fitting. Is prevented. For this reason, even if it becomes high temperature during operation and the inner diameter of the outer ring 3 is greatly expanded due to thermal expansion of the outer ring 3, the press-fit state of the seal core 6a is maintained,
The detachment of the seal 6 is prevented.

FIG. 2 shows an example of a bearing device in which this sealed bearing 1 is used for an auxiliary machine of an automobile. This auxiliary machine is a fan clutch for a small passenger car or the like. The bearing 1 has an outer ring 3 on an inner diameter surface of a housing 11 to which a fan 12 is attached.
Is press-fitted and mounted. The bearing 1 integrated with the housing 11 is attached so that the inner race 2 is fitted to the main shaft 13. The main shaft 13 is generally bolted to a flange of a pump shaft in an engine. A clutch mechanism 14 is provided between the main shaft 13 and the housing 11.

In the above-described embodiment, the case where the core 6a of the seal 6 is press-fitted into the outer ring 3 has been described. Can also be applied to the case where is brought into sliding contact with the outer ring. Further, the seal 6 may be a core bar without the elastic body 6b, and may constitute a labyrinth seal.

Next, an experimental example will be described. For the bearings with seals of Examples and Comparative Examples, the housing 1 of the outer ring 3 was used.
The relationship between the interference and the pull-out force for No. 1 was tested. FIG. 3 shows the experimental results. The sealed bearing according to the example uses the core metal 6a subjected to the soft nitriding in the sealed bearing according to the embodiment shown in FIG. The comparative example differs from the sealed bearing of the example only in that the core metal used was not treated by nitrocarburizing. Core 6a
Has an outer diameter of 60 mm, a width of 5 mm, and a thickness of 0.6 mm.
The pull-out force is a value measured under the following conditions. That is,
The seal was fixed to the outer ring by press-fitting, and the outer ring was fixed to the housing by press-fitting under the condition that the interference between the outer ring and the seal was changed to each level. In this state, the instantaneous force at which the seal came off the outer ring was measured. This force was taken as the pull-out force. The interference between the outer race and the housing was changed to various levels by changing the inner diameter of the housing. The temperature is evaluated at room temperature, that is, at room temperature.

From the experimental results shown in FIG. 3, it can be seen that the drawing force tends to decrease as the interference increases, both in the case where the nitrocarburizing treatment is performed and in the case where the nitrocarburizing treatment is not performed. That is, as the permanent deformation of the seal core increases, the pressing force of the seal core to fix the seal to the outer ring (in other words,
It can be seen that the sealing core metal's tension in the outer ring direction is reduced. Further, it can be seen that by performing the soft nitriding treatment, the pull-out force of the seal is improved in any of the interferences as compared with the case where the seal is not treated.

The effect of the nitrocarburizing treatment is more effective in the case where the pulling force in a state where the interference is reduced due to the difference in thermal expansion between the housing and the outer ring due to the temperature rise is evaluated than in the evaluation at room temperature. The effect according to the usage pattern of can be evaluated,
The temperature was evaluated at room temperature for the following reasons. That is, in this experimental example, the pull-out force was measured without removing the housing (including the fitting force due to the interference), and it was relatively better to perform nitrocarburizing than untreated as described above. Is shown in the experimental results. In addition, when the temperature is increased, a test error due to the temperature is likely to occur. Therefore, the test was not performed at a high temperature, but at a normal temperature at which the test was easily performed.

[0023]

The seal bearing of the present invention has a seal between the inner and outer races serving as the outer race and the inner race for sealing an annular space between the races. In a sealed bearing that has a metal core that is attached by press-fitting, since the core metal has been subjected to a process that reduces permanent deformation, the interference for press-fitting the bearing ring into the housing or shaft is large. Also, even when used in a high-temperature environment, the seal can be kept fixed by press-fitting. In the case where the above-mentioned seal is such that the core is attached to the inner surface of the outer ring by press-fitting, the effect of maintaining the fixation by press-fitting the seal is effective, and the outer ring is made of steel, and the outer ring is made of steel. When the seal is fixed to the aluminum housing by press-fitting, the effect of maintaining the seal by press-fitting is more effective. According to the bearing device of the present invention, a seal for sealing an annular space between the races is provided between the outer race and the inner race, which serves as an inner race. The seal is mounted on one of the races by press fitting. In a sealed bearing with gold, the core metal is treated to reduce permanent deformation, so there is a large interference with press-fitting the bearing ring into the housing or shaft, and it is used in high temperature environments. Even if it is performed, the fixation by press-fitting the seal can be maintained.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a bearing device using a bearing with a seal according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an auxiliary device of an automobile to which the bearing device is applied.

FIG. 3 is a graph showing experimental results showing the relationship between interference and pull-out force in Examples and Comparative Examples.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bearing with a seal 2 ... Inner ring (track ring) 3 ... Outer ring (track ring) 6 ... Seal 6a ... Core 11 ... Housing

Claims (6)

[Claims] A seal is provided between an inner race and an outer race, which serves as an outer race and an inner race, for sealing an annular space between the races. A bearing with a seal, wherein the cored bar is subjected to a process for reducing permanent deformation. 2. The sealed bearing according to claim 1, wherein the seal has a core metal attached to an inner diameter surface of the outer ring by press fitting. 3. The sealed bearing according to claim 2, wherein the outer ring is made of steel, and the outer ring is fixed to the aluminum housing by press-fitting. 4. The sealed bearing according to claim 1, wherein the treatment for reducing the permanent deformation is a nitrocarburizing treatment. 5. The interference between an outer race and a housing to which the outer race is fixed by press fitting is 0.100 mm or more.
The sealed bearing according to any one of claims 4 to 5. 6. A bearing device in which a sealed bearing is fixed to a housing made of a material having a coefficient of linear expansion larger than that of an outer ring of the bearing by press-fitting, wherein the bearing device seals an annular space between an inner ring and an outer ring. This seal has a core bar attached to the inner surface of the outer ring by press-fitting, and the core bar is subjected to a process of reducing permanent deformation. Bearing device.