JPH1162995A - Rolling bearing - Google Patents

Abstract

(57) [Problem] To provide a rolling bearing suitable for use under high temperature and no lubrication. SOLUTION: A radial ball bearing 1 includes an outer ring 3, an inner ring 4,
It has balls 5 and spacers 7 distributed in these spaces. When manufacturing a solid lubricated bearing in the radial ball bearing 1, first, a solid lubricant, a filler and a liquid binder are kneaded to form a paste-like fluid. After cleaning the bearing to which the retainer is not attached and applying a release agent, the balls are equally arranged between the outer ring and the inner ring, and the gap formed by the inner and outer rings and the balls is filled with the paste. After filling, the surface of the filling is shaped, and then the filled bearing is fired in an electric furnace in a constant temperature pattern. After cooling, the bearing is removed from the furnace, and a window 8 for discharging abrasion powder generated during rotation of the bearing is opened at a position where a ball marked in advance is present. Then, preliminary rotation is performed to confirm smooth rotation, and a lubricant film is uniformly formed on the ball 5 and the rolling surface to complete the lubricant film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing which can be used under conditions of high temperature and no lubrication.

[0002]

2. Description of the Related Art Conventionally, when a rolling bearing is used, it is generally lubricated with oil or the like. However, when oil cannot be used due to high temperature or the like, a solid lubricant is used. Examples of the use of a solid lubricant for a rolling bearing include a filler filled with a mixture of a solid lubricant and a binder in a gap between an inner ring and an outer ring (US Pat. No. 4,223,963), and a block of solid lubricant. Processed into a shape (Japanese Utility Model Laid-Open No. 2-87121, Japanese Patent Laid-Open No. 1-126426, Japanese Patent Laid-Open No. 3-27)
No. 2302) is known.

[0003]

However, in the above-mentioned prior art, since the solid lubricant mass is fixed to the press retainer, the solid lubricant falls off the press retainer due to external vibration and impact. Easy and careful use is required.

In low-speed rotation at a high temperature, the bearing is exposed to a severe oxidizing environment. Therefore, it is desirable that the bearing be protected by a thick lubricating film in order to prevent oxidation. Since the radial gap of the bearing is narrowed, rotation is hindered.

Further, it is difficult to machine a block of the solid lubricant into a shape of a cage, and it becomes extremely expensive.

Further, when a cage manufactured by cutting is incorporated into a bearing, a special device such as a groove may be required depending on the shape of the cage, which also leads to an increase in cost. For this reason, there has been a demand for a method of manufacturing an inexpensive solid lubricated rolling bearing.

[0007] Needle bearings and roller bearings are also required to be able to withstand use at high temperatures and without lubrication.

Accordingly, an object of the present invention is to provide a rolling bearing suitable for use under high temperature and no lubrication.

[0009]

To achieve the above object, a rolling bearing according to a first aspect of the present invention provides a solid lubricant in a gap formed by an inner ring and / or an outer ring and a rolling element. It is characterized in that a spacer obtained by firing a filler composed of an inorganic binder and a filler is provided. Thereby, the solid lubricant can be directly filled into the gap formed by the inner and outer races and the rolling elements without fixing the solid lubricant to the press retainer or the like, so that a spacer having an arbitrary shape can be obtained. When solid lubricant is fixed to the press cage as in the past, when subjected to vibration or impact, it separates at the boundary between the solid lubricant and the press cage, and the solid lubricant falls off the press cage. Although the rolling bearing according to the first aspect has no fixed portion even when subjected to vibration or impact from the outside, it does not fall off and comes into contact with the inner and outer races and the rolling element through a small space. As a result, the distance between the inner and outer races and the rolling elements is reduced, and the collision energy generated when receiving a vibration or impact is small, and there is no significant damage. Here, the ratio of the spacer containing the solid lubricant is preferably set to 7/9 or more, so that the spacer has an excellent lubricating action.

In the case of bearing steel (SUJ2), the radial gap as the gap is a so-called C3 gap (1).
3 to 28 μm) or more, preferably 200 μm or more and 500
It is desirable that the thickness be not more than μm. It is desirable that a bearing used for low-speed rotation at high temperatures be formed with a thick lubricating film to prevent oxidation. When subjected to a high pressure such as a surface pressure generated on a surface, they are connected to each other, and by repeating this, the thickness of the solid lubricant is increased. In this case, the thickness of the film varies depending on conditions such as the ambient temperature, the rotation speed, and the load, but reaches an equilibrium at a specific upper limit thickness under each condition.

Therefore, if the radial gap of the bearing is a normal gap at a high temperature, the gap is narrowed in a short time and rotation is hindered.
This can be avoided by setting the gap to 3 or more (13 to 28 μm), preferably 200 to 500 μm. By the way, it is known that the thickness of the solid lubricating film is affected by the material constituting the bearing, and the above-mentioned values are for bearing steel (SUJ2), and for stainless steel (SUS440C), , Preferably a C3 gap (13 to 28 μm) or more and 500 μm or more.
m or less. Thereby, long-time rotation can be ensured while preventing oxidation. Further, even if a thick lubricating film having excellent oxidation resistance is formed, the radial gap is not narrowed and rotation is not hindered.

Further, the spacer is filled with a mixture of a solid lubricant, an inorganic binder, and a filler in a semi-solid state in a gap formed by the inner and outer rings and the rolling elements, and is dried.
Desirably, it is manufactured by being solidified by firing. In the production of a solid lubricated bearing, a void formed by the inner and outer rings and rolling elements can be easily filled by using a paste-like fluid comprising a solid lubricant, a filler and a liquid binder. Thereafter, by firing the filled bearing at a required temperature, a solid lubricated bearing can be easily provided. In needle bearings, solid lubricant needle bearings that can be used at high temperature and without lubrication by filling paste consisting of solid lubricant, binder and filler into the gap formed by the outer ring, cage and needle, and then firing Can be provided.
Also, in the case of a roller bearing, a solid lubricated roller bearing that can be used at high temperature and without lubrication can be provided. In this manner, any type of bearing having a space capable of accommodating the solid lubricant can be easily manufactured, and the machining and assembling costs can be reduced.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the rolling bearing according to the present invention will be described. The rolling bearing in the present embodiment is applied to a radial ball bearing. FIG. 1 is a sectional view showing the structure of a part of the radial ball bearing according to the embodiment.

The radial ball bearing 1 includes an outer ring 3, an inner ring 4, a ball 5, and spacers 7 distributed in these spaces.
Having. As the material of the outer ring 3, the inner ring 4 and the balls 5, bearing steel, stainless steel, heat-resistant steel such as SKH, ceramics such as silicon nitride, cermet, and the like are used.
The same material is used when applied to a needle bearing and a roller bearing described later.

As a solid lubricant used for the spacer 7, a natural or artificial graphite material, boron nitride, molybdenum disulfide, or the like is used, but when used, these may be used alone or in combination of two or more. . For example,
In the case of use reciprocating between the atmosphere and vacuum, use of a combination of graphite and molybdenum disulfide can be considered.

In addition, a binder is used to bind the solid lubricant to give it a shape. As the binder, an inorganic material or an organic material is used depending on the use conditions. For example,
When used in a high temperature atmosphere, an inorganic material having excellent heat resistance is used. Further, as the filler, glass fiber, heat-resistant resin fiber and the like can be considered, and it is preferable to use a fiber-reinforced composite material in which these are mixed and reinforced.

The spacer 7 has a shape conforming to the rolling surfaces of the inner and outer rings 4 and 5 and the shape of the ball 5. FIG. 2 is a cross-sectional view showing the structure of the radial bearing as viewed from the direction of arrows AA in FIG. As shown in FIG. 2, the width of the spacer 7 in the axial direction is preferably larger than the diameter of the ball 5 and smaller than the width of the bearing. The cross-sectional shape of the spacer may be circular, and the axial width of the spacer may be wider than the width of the bearing if there are no restrictions such as mounting conditions.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Radial ball bearings 1 in which the ratio of spacers containing solid lubricant to spacers containing no solid lubricant is varied.
Was used as Example 1, and the change in the wear amount when the radial ball bearing 1 was rotated was examined. In addition, a commercially available bearing with a cage was used as a comparative example, and the amount of wear when rotated was shown as a result.

Here, the material of the spacer 7 includes graphite powder "product of Chuetsu Graphite Co., Ltd., BF-8A", and binder "product of AMERCO PRODUCTS, INC.
erama-Bind 542 ", carbon fiber" Nippon Carbon Products Co., Ltd., Carbonlon Z carbon chop
NFC1 "was used. A mixture of these is called a paste, and the spacer is obtained by firing and solidifying the spacer.

The specifications of the bearing are as follows.

Type of rolling bearing: 6206 Material of outer ring / inner ring / ball: stainless steel (440C) Cage of bearing of comparative example: press retainer Spacer of bearing of Example 1: graphite component 25%, inorganic binder component 70 %, Carbon fiber 5% FIG. 3 is a diagram showing a configuration of a test apparatus. In the test apparatus 10, the test bearing 1 is attached to the rotating shaft 13 supported by the support bearing 12.
4 was heated in a thermostat 16 and operated while applying a load Fr via a radial load application system. After a certain period of time, the operation was stopped, and the radial clearance of the bearing after the test was measured. Table 1 shows the relationship between the ratio of the spacer containing the solid lubricant and the wear amount of the bearing.

[0022]

[Table 1] Here, the ratio of the spacer containing the solid lubricant is calculated using the number of the spacers containing the solid lubricant as a numerator and the number of all the spacers as a denominator. The commercially available bearing with a cage of the comparative example has no lubricant.

The test conditions were as follows: temperature: 350 ° C., rotation speed:
100 rpm, load Fr: 50 kgf, rotation time: 21
Time.

From these results, when the proportion of the spacer containing the solid lubricant in the first embodiment is large, the supply of the solid lubricant is sufficient, and the thickness of the solid lubricant film to be formed becomes large. It can be seen that the radial gap has become smaller. Also, if the ratio of the spacer containing the solid lubricant is too small, the supply of the solid lubricant is insufficient, and the thickness of the generated solid lubricant film becomes thin, so that the lubrication becomes insufficient and wear occurs. It can be seen that the radial gap of the bearing is large. That is, when the ratio of the spacer containing the solid lubricant is 7/9 or more, an excellent lubricating action is exhibited.

When a commercially available bearing with a retainer, which is a comparative example, was rotated, no lubricant was supplied, so that the amount of wear was extremely large and the radial clearance was greatly increased.

[Embodiment 2] Next, several kinds of radial ball bearings having different radial clearances were set to Embodiment 2, and the change in the life of the bearing when the bearing was rotated was examined. The configuration of the radial ball bearing according to the second embodiment is the same as that of the first embodiment. The service life was determined according to the time required to stop rotation due to the increase in torque.

The specifications of the bearing are as follows.

Type of rolling bearing: 6206 Material of outer ring / inner ring / ball: bearing steel (SUJ2) Type of radial gap: 13, 20, 200, 500 μm Spacer of bearing in embodiment 2: graphite component 25%, inorganic binder component 70%, carbon fiber 5% The test apparatus is the one shown in FIG. Table 2 shows the relationship between the radial gap of the spacer and the life. The commercially available bearing with a cage of the comparative example has no lubricant.

[0029]

[Table 2] The test conditions were as follows: temperature: 350 ° C., rotation speed: 100 rpm
m, load Fr: 50 kgf.

From these results, when the radial gap is small, the thickness of the solid lubricant film to be formed becomes large, and the life is reached in a relatively short time. In addition, when the radial gap is large, the thickness of the solid lubricating film to be formed is relatively smaller than the radial gap, so that it takes a long time until the radial gap is clogged and the life is extended.

As a comparative example, when a commercially available bearing with a cage was rotated, no lubricant was supplied, so that seizure occurred and the life was shortened. That is, it has been found that when the radial gap is small, clogging occurs early due to the generated solid lubricant film, and conversely, when the radial gap is large, it takes a long time to close the gap. However, in order to maintain smooth rotation, it is not preferable that the radial gap is too large. As an appropriate radial gap,
A so-called C3 gap (13 to 28 μm) or more, preferably 200 to 500 μm is recommended.

Next, the manufacturing process of the solid lubricated bearing in the radial ball bearings 1 of the first and second embodiments will be described. First, a solid lubricant, a filler and a liquid binder (here, as a solid lubricant, graphite powder “Chuetsu Graphite Co., Ltd. product, BF / 8A”, binder “US AREMC
O PRODUCTS, INC. Product, Cerama-
Bind 542 "and carbon fiber" Carbon Z Carbon Chop NFC1 "as a filler. ) Was kneaded to obtain a paste-like fluid. Also, NSK 6206 manufactured by NSK Ltd.
Was used.

First, the bearing to which the retainer is not attached is washed, and a release agent is applied (spray or so-called thrusting may be applied). Then, balls are equally arranged between the outer ring and the inner ring, and the inner and outer rings are formed. -The paste was filled in the void formed by the ball. The filling method may be performed manually using a spatula or the like, or may be performed using an automatic device such as an injection machine driven by compressed air, a hydraulic motor, or the like. After filling, the surface of the packing is shaped, and then the filled bearing is heated at a constant temperature pattern (1 ° C./min. To 93 ° C./min.) And maintained for 1 hour, followed by 1 hour at 1 ° C./min. To 186 ° C. Maintain, 2 more
The temperature was raised to 79 ° C at 1 ° C per minute and maintained for 2 hours, then 5 minutes per minute.
Cool to room temperature at ° C. ) Was fired in an electric furnace.

After cooling, the bearing was taken out of the furnace, and a window 8 for discharging abrasion powder generated during rotation of the bearing was opened at a position where a ball previously marked was present. FIG. 4 is a sectional view showing the structure of a part of a radial ball bearing in which a window for discharging abrasion powder generated when the bearing rotates is opened. FIG. 5 is a sectional view showing the structure of the radial ball bearing as viewed from the direction of the arrow BB in FIG.

Incidentally, instead of providing the window 8, the inner ring and / or
Alternatively, a slit 9 may be formed at the boundary between the outer ring and the filler. FIG. 6 is a cross-sectional view showing the structure of a part of a radial ball bearing in which a slit is provided at the boundary between the inner and outer rings and the filler. FIG. 7 is a sectional view showing the structure of the radial ball bearing as viewed from the direction of the arrows CC in FIG. In this case, it does not become a separated spacer, but becomes an integral filling 7a.

Thereafter, preliminary rotation was performed to confirm smooth rotation, and a lubricant film was uniformly formed on the ball 5 and the rolling surface to complete the lubrication.

Next, the solid lubricating needle bearing will be described. FIG. 8 is a sectional view showing the structure of a part of the needle bearing. FIG. 9 is a sectional view showing the structure of the needle bearing as viewed from the direction of the arrows DD in FIG. FIG. 10 is a cross-sectional view showing the structure of the needle bearing as viewed from the direction of the arrows EE in FIG. A gap formed by the outer ring 23, the cage 26 and the needle 25 is filled with a paste composed of a solid lubricant, a binder, and a filler, and then fired to provide a solid lubrication needle bearing that can be used at high temperature and without lubrication. Completed.

Here, the solid lubricant, binder and filler are the same as those used in the manufacturing process of the solid lubricated bearing in the radial ball bearing. RLM304020 manufactured by NSK Ltd. was used for the bearing. This bearing is a solid-type needle bearing with an outer diameter of 40 x width 30, inner diameter 3
It has dimensions of 0 mm.

When applied to the needle bearing 21, the role of the retainer is important. That is, the spacer 27 including the solid lubricant has four side surfaces surrounded by the raceway surface of the cage 26, the adjacent rollers 25, and the outer ring 23, and the remaining two end surfaces are the outer ring 23
Are stopped by the flanges 28 at both ends of the lens, and are stably maintained.

Although the retainer 26 has a linear cross section parallel to the outer ring, the retainer 26 is not limited to the linear cross section.
Step 2 swelling toward the axial center in a range smaller than the diameter of the roller
6a. FIG. 11 is a cross-sectional view showing a structure of a needle bearing having a retainer in which a step portion bulging toward the axial center is formed in a range smaller than the diameter of the roller.

In the manufacturing process of the needle bearing 21, after the bearing is washed, a release agent is applied in a state of being separated from the outer ring 23, the retainer 26 and the needle 25, and a solid lubricant is applied from the inside of the outer ring 23 of the needle bearing 21. The grooved portion of the outer ring was filled with a paste made of, for example, a spatula, and the filled surface was rubbed at the sectional height of the brim 28 to smooth the surface. Then, the retainer 26 was inserted inside the outer ring 23 without touching the filling surface. Further, the needle 25 was sequentially inserted into the pocket of the retainer 26 from the inside, and the needle bearing 21 was assembled.

This was fired under the same conditions as in the manufacturing process of the solid lubricated bearing in the radial ball bearing. Thereafter, preliminary rotation was performed to confirm smooth rotation, and a lubricant film was further uniformly formed on the needle and outer ring rolling surfaces to complete the rotation.

Next, a self-aligning roller bearing will be described as an example of the roller bearing. FIG. 12 is a sectional view showing the structure of a part of the self-aligning roller bearing. FIG. 13 is a cross-sectional view showing the structure of the spherical roller bearing as viewed from the direction of the arrow FF in FIG. The space formed by the inner ring 34, the retainer 36, and the rollers 35 is filled with a paste composed of a solid lubricant, a binder, and a filler, and then fired to enable solid lubrication self-alignment that can be used at high temperature and without lubrication. A roller bearing was manufactured.

Here, the solid lubricant, the binder and the filler are the same as in the manufacturing process of the solid lubricated bearing in the radial ball bearing, and the bearing is manufactured by Nippon Seiko Co., Ltd.
210 was used. In this bearing, the conventional cage is used as the cage.However, if the spacer can be surrounded by the cage, adjacent rollers, the inner ring raceway surface and the brim, and the opening for filling can be secured, May be used.

When applied to roller bearings, the role of the cage is important. That is, in the self-aligning roller bearing 31, the spacer 37 containing the solid lubricant has four raceways surrounded by the raceway surfaces of the retainer 36, the adjacent rollers 35 and the inner ring 34, and the remaining two end surfaces are formed by the collar 34a and the middle collar 34b. It becomes the shape stopped by.

In the cylindrical roller bearing 41, a so-called N
In the case of the J-type press retainer, the spacer 47 containing the solid lubricant has a shape surrounded by the retainer 46, the adjacent rollers 45, the raceway surface of the inner ring 44, and the collar 44a of the inner ring, and is stably maintained. You. FIG. 14 is a sectional view showing the structure of a part of a cylindrical roller bearing having an NJ-type press retainer. FIG. 15 is a sectional view showing the structure of the cylindrical roller bearing as viewed from the direction of the arrows GG in FIG. This is the N-type cage 146,
The same applies to the case of the NF type retainer 246. FIG. 16 shows N
It is sectional drawing which shows the structure of the cylindrical roller bearing which has a type | mold retainer. FIG. 17 is a sectional view showing the structure of a cylindrical roller bearing having an NF type cage.

Further, similarly, in the case of the tapered roller bearing 51, the spacer 57 containing the solid lubricant is provided with the retainer 56,
Adjacent rollers 55, inner ring 54 and flanges 5 at both end surfaces
It is stably maintained in the shape surrounded by 4a and 54b. FIG. 18 is a sectional view showing the structure of a tapered roller bearing.

A method for manufacturing the roller bearing will be described. That is, after cleaning the bearing, a mold release agent is applied, and a paste made of a solid lubricant or the like is filled with a spatula or the like from the opening between the inner ring of the bearing and the retainer, but it is necessary to fill all the openings. There is no. After filling, the inner wall of the brim was scraped with the extended surface to smooth the end surface. The upper end was shaped with a spatula on the same surface as the lower surface (it may be the upper surface) of the cage.

This was fired under the same conditions as in the manufacturing process of the solid lubricated bearing in the radial ball bearing. Thereafter, preliminary rotation was performed to confirm smooth rotation, and a lubricant film was further rolled to uniformly form the outer ring rolling surface to complete the rotation.

[0050]

According to the rolling bearing according to the first aspect of the present invention, a filler comprising a solid lubricant, an inorganic binder, and a filler is fired in a gap formed by the inner ring and / or the outer ring and the rolling element. Since the solid spacer is provided, the solid lubricant can be directly filled into the gap formed by the inner and outer races and the rolling elements without fixing the solid lubricant to the press retainer or the like, so that a spacer having an arbitrary shape can be obtained. . When solid lubricant is fixed to the press cage as in the past, when subjected to vibration or impact, it separates at the boundary between the solid lubricant and the press cage, and the solid lubricant falls off the press cage. Although the rolling bearing according to the first aspect is easy to vibrate,
Since there is no fixed part even when it receives an impact, it does not fall off, and it comes into contact with the inner and outer rings and rolling elements through a small gap, so the gap between the inner and outer rings and rolling elements is reduced,
The collision energy generated when receiving vibration and shock is small, and there is no significant damage. In this way,
Excellent impact resistance.

It is desirable to form a thick lubricating film on a bearing used for low-speed rotation at high temperature to prevent oxidation. However, a solid lubricant composited with an inorganic binder is When subjected to a high pressure, such as the surface pressure generated on the ball and the race surface below, they are connected to each other and this is repeated, thereby increasing the thickness of the solid lubricant. Therefore, it is possible to provide a rolling bearing suitable for use under high temperature and no lubrication. It is also possible to supply needle bearings and roller bearings that can be used under high temperature and no lubrication.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a structure of a part of a radial ball bearing according to an embodiment.

FIG. 2 is a cross-sectional view showing the structure of the radial bearing as viewed from the direction of arrows AA in FIG.

FIG. 3 is a diagram illustrating a configuration of a test apparatus.

FIG. 4 is a sectional view showing the structure of a part of a radial ball bearing in which a window for discharging abrasion powder generated when the bearing rotates is opened.

FIG. 5 is a sectional view showing the structure of the radial ball bearing as viewed from the direction of the arrows BB in FIG. 4;

FIG. 6 is a cross-sectional view showing a structure of a part of a radial ball bearing in which a slit is provided at a boundary between an inner ring and an outer ring and a filler.

FIG. 7 is a sectional view showing the structure of the radial ball bearing as viewed from the direction of the arrows CC in FIG. 6;

FIG. 8 is a sectional view showing the structure of a part of the needle bearing.

FIG. 9 is a cross-sectional view showing the structure of the needle bearing as viewed from the direction of arrows DD in FIG. 8;

FIG. 10 is a sectional view showing the structure of the needle bearing as viewed from the direction of the arrows EE in FIG. 8;

FIG. 11 is a cross-sectional view showing a structure of a needle bearing having a retainer in which a step portion bulging toward the axial center in a range smaller than the diameter of the roller is formed.

FIG. 12 is a sectional view showing the structure of a part of the self-aligning roller bearing.

13 is a sectional view showing the structure of the self-aligning roller bearing as viewed from the direction of the arrow FF in FIG. 12;

FIG. 14 is a sectional view showing the structure of a part of a cylindrical roller bearing having an NJ-type press retainer.

FIG. 15 is a cross-sectional view showing the structure of the cylindrical roller bearing as viewed from the direction of arrows GG in FIG.

FIG. 16 is a sectional view showing a structure of a cylindrical roller bearing having an N-type cage.

FIG. 17 is a sectional view showing a structure of a cylindrical roller bearing having an NF-type cage.

FIG. 18 is a sectional view showing the structure of a tapered roller bearing.

[Explanation of symbols]

 1 Radial Ball Bearing 3, 23, 33, 43, 53 Outer Ring 4, 34, 44, 54 Inner Ring 5 Ball 7, 27, 37, 47 Spacer 21 Needle Bearing 25 Needle 26, 36, 46, 56 Cage 31 Self-Aligning Roller bearings 35, 45, 55 Rollers 41 Cylindrical roller bearings 51 Tapered roller bearings

Claims (1)

[Claims] 1. A rolling bearing wherein a spacer formed by firing a solid lubricant, a filler comprising an inorganic binder and a filler is provided in a gap formed by an inner ring and / or an outer ring and a rolling element.