JP2008002494A - Cage for rolling bearing and rolling bearing using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel cage for a rolling bearing inexpensively manufacturable and having excellent resistance against wear and seizure and to provide the rolling bearing using it. <P>SOLUTION: This cage 4 for holding a rolling element 3 for the rolling bearing is made metal, shot peening is applied onto at least a surface 5 of a sliding part with the rolling element 3, and the maximum roughness of the surface is 2.5 μm or less. Consequently, it is possible to provide the inexpensively manufacturable rolling bearing having excellent resistance against wear and seizure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing cage in which a sliding surface of a member that is in sliding contact with a rolling element, an inner ring, and an outer ring is subjected to wear resistance treatment and low wear resistance treatment, and a rolling bearing using the same.

  Conventionally, rolling bearings, which are indispensable as parts for industrial machines and automobiles, are made of steel for the inner ring supported on the rotating shaft body side, the outer ring supported on the stationary body side, and the multiple rolling elements provided between them. Generally, the cage configured to hold each of the rolling elements is made of a metal such as brass. In addition, such a rolling bearing is always supplied with a lubricant such as oil or grease between the inner ring and the outer ring, thereby reducing the sliding friction of the rolling element, etc. The rotation is smoother.

  However, when this type of rolling bearing is applied to a shaft that rotates at an ultra-high speed, such as a turbocharger or a gas turbine shaft, the portion may become abnormally hot due to sliding friction and seizure may occur. is there. That is, with the high-speed rotation of the shaft body, not only the rolling elements of the bearing, the inner ring, the outer ring, and the cage are rubbed against each other, but also the fluidity of the lubricant such as grease decreases due to the frictional heat, Friction powder is entangled with each member to further promote wear. If the rolling elements and the cage are damaged due to the progress of the wear, the rotation on the shaft body side is abruptly deteriorated and the vibration becomes intense and seizure occurs.

  For this reason, for example, this rolling element is made of a ceramic material having excellent heat resistance to suppress the occurrence of seizure. That is, since the ceramic material is lighter than steel, the centrifugal force applied to the rolling elements and the rotational energy for the rotation of the rolling elements are small, and therefore the force applied between the rolling elements and the outer ring is small. Ceramic materials are also excellent in wear resistance.

However, even when the rolling element is made of a ceramic material in this way, the cage may be worn by rubbing against the outer ring, or the wear of each member may be accelerated by the frictional heat and wear powder generated at that time. It is difficult to sufficiently suppress the occurrence of image sticking.
Therefore, in the following Patent Document 1, for example, not only this rolling element is made of a ceramic material, but also a cage for holding this ceramic rolling element is made of a lightweight synthetic resin such as polyimide resin. The occurrence of seizure due to the material of the rolling elements and the cage is prevented.

On the other hand, in Patent Document 2 below, a sealed rolling bearing provided with a sealing device is disclosed, and a shot peening process as disclosed in Patent Document 3 is performed on a seal groove of the rolling bearing. There has been disclosed a technique for preventing foreign matters from being mixed and maintaining the lubrication state of the seal groove portion well over a long period of time.
Japanese Patent Application Laid-Open No. 06-173756 JP 2005-69404 A Japanese Patent No. 3357661

By the way, like the rolling bearing currently disclosed by the said patent document 1, when a rolling element is comprised with a ceramic or a cage is comprised with synthetic resins, such as a polyimide resin, it will manufacture compared with what was comprised with the conventional metal. There is a problem that the cost increases significantly.
Therefore, the present invention has been devised to solve such a problem, and the purpose thereof is a novel rolling bearing retainer that is low in manufacturing cost and excellent in wear resistance and seizure resistance. And a rolling bearing using the same.

In order to solve the above-mentioned problem, the invention of claim 1
In a cage for holding a rolling element for a rolling bearing, the material is metal, and at least the sliding part surface with the rolling element is subjected to shot peening treatment, and the maximum roughness of the surface is 2.5 μm or less. This is a rolling bearing cage.
As described above, the rolling bearing retainer of the present invention is in a state in which the surface of the sliding part is formed with a surface texture in which fine irregularities are uniformly dispersed by the shot peening treatment on the surface of the sliding part. Yes. For this reason, the lubricant is held in the concave portion of the surface structure and the surface is always covered with a fluid film, so that the oil film does not easily break and the good lubrication state is maintained for a long time. Can do.

Further, by performing such shot peening treatment, not only a fine uneven structure is formed on the surface of the sliding part, but also the compressive residual stress on the surface of the sliding part is increased. Wear and heat generation can be reduced.
As a result, wear resistance and lubricity are greatly improved to prevent seizure, and metal materials such as steel and brass can be used as they are in the past, avoiding a significant increase in manufacturing costs. Can do.

In addition, this shot peening treatment can remove burrs and turning marks in the turning process and press fixing, scales and welds in the heat treatment process, etc., and is therefore effective in improving the cleanliness. The condition is improved. The shot peening process may be performed not only on the surface of the sliding part but also on the entire surface.
Here, the reason why the maximum roughness of the sliding surface is defined as “2.5 μm” or less is that when it exceeds “2.5” μm, the surface becomes non-uniform and the frictional resistance increases. is there. The maximum roughness of the sliding surface is desirable to be small, but as described above, at least “0.5 μm” is required in order to exhibit a good oil film holding function due to the recess, and more preferably “1.0 μm” or more.

  In addition, the “shot peening treatment” in the present invention is not particularly limited as long as it is a shot (particle) having a predetermined particle diameter that is sprayed onto the surface of the sliding portion with a high-pressure gas at a high speed. It is effective to use a “Wonder Process Craft” process (a shot peening process (registered trademark) provided by Fuji Seisakusho and Fuji Machine Sales Co., Ltd.).

As an example, a powder having a particle size of 40 to 200 μm and a hardness equal to or higher than the hardness of the cage (for example, the same metal material or SiO ₂ as the cage) is used as a jetting particle, and this is used as a jetting speed. By spraying onto the surface of the cage at a speed of 100 m / sec or more for several seconds to several tens of seconds, rapid heating and quenching in the temperature range above the A3 transformation point is instantaneous when the surface of the cage is made of iron-based material. Repeatedly, a process having a heat treatment effect and a training effect is performed.
As a result, martensite, recrystallization, and refinement of the retained austenite in the metal surface layer are performed, and a dense, high hardness and tough structure can be obtained. In addition, the internal residual compressive stress on the surface can be increased.

In addition, a SiO ₂ powder having a hardness of Hv 800 or more and a particle size of _{20 to 200} μm is used as a spray particle, and this is sprayed onto the surface of the cage at a spray speed of 50 m / sec or more to control the temperature near the surface. By raising the temperature above the A3 transformation point in the case of a ferrous material, or higher than the recrystallization temperature in the case of a non-ferrous material, and forming an oil sump consisting of innumerable concave portions having a minute cross-sectional arc shape on the surface. Further, wear due to running out of the lubricant can be prevented.

Next, the invention of claim 2
The rolling bearing cage according to claim 1, wherein the shot-peened surface has a hardness of Hv 800 or more.
As a result, even if foreign matter is mixed into the sliding contact surfaces of the cage, the race and the rolling elements, the sliding contact surfaces are not damaged or worn, and stable performance can be ensured.
The invention of claim 3
The rolling bearing cage according to claim 1 or 2, wherein a film in which a lubricant is dispersed is formed on the surface subjected to the shot peening treatment.
Thereby, the metal contact of the slidable contact surface between the cage, the race and the rolling element can be prevented more reliably. In particular, an excellent effect can be exhibited in the absence of lubricant or in a non-lubricated environment.

Here, as a method of forming a coating film in which a solid lubricant is dispersed on the surface of a shot peening layer as in the present invention, for example, as proposed in Patent Document 3, a spray powder used for shot peening treatment is used. As a mixture of solid lubricant particles such as molybdenum disulfide (MoS ₂ ), tungsten disulfide (WS ₂ ), boron nitride (BN), and fluororesin (for example, PTFE), In addition, it is possible to easily form a film in which these solid lubricants are uniformly dispersed on the surface of the sliding portion only by performing the shot peening process.

The invention of claim 4
A rolling bearing comprising the rolling bearing cage according to any one of claims 1 to 3.
As a result, if only the cage is replaced in a conventional rolling bearing, the friction on the surface of the sliding portion of the cage can be reduced, so that it can be used under high speed rotation and high load without significantly increasing the manufacturing cost. The life of rolling bearings can be improved.

According to the present invention, since the surface of the sliding portion made of metal is subjected to shot peening, the wear resistance and lubricity of the sliding portion surface are improved.
This suppresses heat generation due to friction and makes it difficult for seizure to occur, thereby extending the life of a rolling bearing used under ultra-high speed rotation, such as a turbocharger or a gas turbine shaft.
Moreover, since metal materials, such as steel and brass, can be used as they are conventionally, it is possible to avoid a significant increase in manufacturing cost.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<First Embodiment>
FIG. 1 is a partially broken perspective view showing an example of a deep groove ball bearing which is one of rolling bearings 10 according to the present invention.
As shown in the figure, this deep groove ball bearing 10 includes an inner ring 1 having a raceway groove 1a on the outer peripheral surface, an outer ring 2 having a raceway groove 2a facing the raceway groove 1a of the inner ring 1 on the inner peripheral surface, and these raceway grooves 1a. , 2a and a plurality of balls (rolling elements) 3, 3...

In addition, the balls 3, 3... Of the deep groove ball bearing 10 are independently held for rolling by the balls 3 by a metal cage 4 processed into a ring shape.
As shown in FIG. 2, the retainer 4 is formed by processing a pair of steel metal plates 4a and 4a having a ring shape into a corrugated shape, and connecting these metal plates 4a and 4a with rivets 4b so as to face each other. Each of the spaces 4c, 4c,... Accommodates each of the balls 3, 3... And partially surrounds them, and moves along with the balls 3, 3. Yes.

And in the deep groove ball bearing 10 according to the present invention having such a configuration, the sliding surface 5 of the cage 4, that is, the surface 5 partially surrounding each ball 3, 3 ... A shot peening process such as WPC (registered trademark) as described above is performed.
And, the sliding portion surface 5 subjected to this shot peening treatment has a surface texture in which the maximum roughness of the surface is 2.5 μm or less and the surface has a fine unevenness uniformly dispersed, The lubricant is held in the concave portions of the concave and convex portions so that a fluid film is always formed.
Therefore, good lubricity can be maintained over a long period of time, and wear of the sliding portion surface 5 can be prevented by increasing the compressive residual stress due to shot peening.

<Second Embodiment>
FIG. 3 is a partially broken perspective view showing an example of an angular ball bearing which is one of the rolling bearings 10 according to the present invention.
As shown in the figure, this angular ball bearing 10 has an inner ring 1 having a raceway groove 1a on the outer peripheral surface and a raceway groove 2a facing the raceway groove 1a of the inner ring 1 on the inner peripheral surface, as with the deep groove ball bearing 10. It has the structure provided with the outer ring | wheel 2 and several ball | bowl (rolling body) 3, 3 ... arrange | positioned so that rolling between these raceway grooves 1a and 2a is possible.
In addition, the balls 3, 3... Of the deep groove ball bearing 10 are held in a freely rollable manner for each ball 3 by a metal cage 4 processed into an annular shape.

The retainer 4 is formed by punching a circular receiving hole 4e at a predetermined interval in a metal ring body 4d having an L-shaped cross section, and in each receiving hole 4e, 4e. Are partially enclosed and moved along the raceway grooves 1a, 2a together with the balls 3, 3,.
In the deep groove ball bearing 10 according to the present invention having such a configuration, the sliding portion surface 5 of the retainer 4, that is, the surface 5 of each of the receiving holes 4e, 4e,. A shot peening process similar to that of the embodiment is performed.

Therefore, as in the first embodiment, the sliding surface 5 can maintain good lubricity over a long period of time, and wear of the sliding surface 5 due to an increase in compressive residual stress due to shot peening. Can be prevented.
In high-speed angular contact ball bearings and the like, so-called machined cages 4 made of a copper alloy such as brass as shown in FIG. 4 are employed. The same effect can be obtained by performing the same shot peening treatment as described above on the surface 5 of the accommodation holes 4e, 4e.

However, in the case of the cage 4 made of a copper alloy such as brass, it is not possible to obtain a hardness of Hv 800 or higher like the steel cage 4, but the hardness is surely increased by performing shot peening treatment. In addition, the effect of retaining the lubricant by controlling the roughness can be obtained in the same manner as in the above embodiments.
In addition, when this cage 4 is guided (contacted) by the inner ring 1 or the outer ring 2, if the shot peening treatment as described above is performed on the contacted portion, wear or heat generation at that portion can be prevented. It ’s still good.
Further, this point is not limited to the ball bearings such as the angular ball bearings as in the present embodiment, but can be applied to the roller bearings such as the cylindrical roller bearings and the self-aligning roller bearings as they are.

<Third Embodiment>
FIG. 5 is a sectional view showing an example of a double row cylindrical roller bearing which is one of the rolling bearings 10 according to the present invention.
As shown in the figure, this double-row cylindrical roller bearing 10 has an inner ring 1 having double-row raceway surfaces 1b and 1b on the outer peripheral surface, and a raceway surface 2b facing the raceway surfaces 1b and 1b of the inner ring 1 on the inner peripheral surface. It has the structure provided with the outer ring | wheel 2 which has, and several roller (rolling element) 6,6 ... arrange | positioned so that rolling between these track surfaces 1b and 2b is possible.
Further, the rollers 6, 6... Of the double-row cylindrical roller bearing 10 are held in a freely rollable manner for each roller 6 by a metal cage 4 processed into a comb shape.

As shown in FIG. 6, the retainer 4 has a plurality of pockets 4h formed by protruding a plurality of comb teeth 4g from the ring-shaped metal retainer body 4f to the left and right at a predetermined interval. Each of the pockets 4h, 4h,... Accommodates and partially surrounds the rollers 6, 6 ..., and moves along the raceway surfaces 1b, 2b together with the rollers 6, 6 ....
In the double-row cylindrical roller bearing 10 according to the present invention having such a configuration, the sliding portion surface 5 of the cage 4, that is, the surface 5 of each pocket 4h, 4h,. A shot peening process similar to that in the first and second embodiments is performed.

Therefore, as in the first and second embodiments, the sliding surface 5 can maintain good lubricity over a long period of time and increase the residual compressive stress due to shot peening. 5 can be prevented.
Similarly to the above embodiment, when the cage 4 is made of a copper alloy such as brass, it is impossible to obtain a hardness of Hv 800 or higher as in the steel cage 4, but a shot peening treatment is performed. As a result, the hardness is reliably increased, and the effect of retaining the lubricant by controlling the roughness can be obtained in the same manner as in the above embodiments.

In addition, when the cage 4 is guided by the inner ring 1 or the outer ring 2, if the shot peening treatment as described above is performed on the portion that serves as the guide surface, wear or heat generation at that portion is prevented. It's even better because you can.
Further, this point is not limited to the double-row cylindrical roller bearing as in the present embodiment, but can be applied as it is to a roller bearing such as a self-aligning roller bearing. The same effects as described above can also be obtained when applied to the roller end face of the cage cage, the sliding portion of the cage, and the sliding portion of the cage pocket.

1 is a partially broken perspective view showing an example of a deep groove ball bearing which is one of rolling bearings 10 according to the present invention. It is a partial side view which shows an example of the holder | retainer used with a deep groove ball bearing. It is a partially broken perspective view showing an example of an angular ball bearing which is one of the rolling bearings 10 according to the present invention. It is a perspective view which shows an example of the machined cage used with an angular contact ball bearing. It is sectional drawing which shows an example of the double row cylindrical roller bearing which is one of the rolling bearings 10 concerning this invention. It is a partial top view which shows an example of the comb type | mold retainer used with a double row cylindrical roller bearing.

Explanation of symbols

1 ... Inner ring
2 ... Outer ring
3 ... ball (rolling element)
4 ... Retainer
4a ... Metal plate 4b ... Rivet 4c ... Space 4d ... Ring body 4e ... Housing hole 4f ... Cage body 4g ... Comb tooth body 4h ... Pocket 5 ... Sliding part surface (shot peening process)
6 ... Roller (rolling element)
10. Rolling bearing

Claims (4)

  In a cage for holding a rolling element for a rolling bearing, the material is metal, and at least the sliding part surface with the rolling element is subjected to shot peening treatment, and the maximum roughness of the surface is 2.5 μm or less. A cage for a rolling bearing characterized by that.   2. The rolling bearing cage according to claim 1, wherein the hardness of the surface subjected to the shot peening treatment is Hv 800 or more.   The rolling bearing retainer according to claim 1 or 2, wherein a film in which a lubricant is dispersed is formed on the surface subjected to the shot peening treatment.   A rolling bearing comprising the rolling bearing cage according to any one of claims 1 to 3.

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