JP2006194407A - Rolling device and rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling device and a rolling bearing having good lubricating performance while preventing its operation stop due to break of structural materials. <P>SOLUTION: A solid lubricant for a cage 1 is formed by sintering and joint with a metal or an alloy. At this time, the content of the solid lubricant is increased at an axial central portion 1b than at an axial end 1c, thus improving strength while securing superior lubricating performance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling device and a rolling bearing, and more particularly to a rolling device and a rolling bearing that are solid lubricants.

For rolling bearings used in high temperature, vacuum or vacuum high temperature environments, when a lubricant with a high vapor pressure such as a general grease composition is used, the lubricant evaporates in the atmosphere. Since the effect of lubrication cannot be sustained, solid lubrication is performed. Examples of rolling bearings that are solid-lubricated in this way are shown in Patent Documents 1 and 2. In these patent documents, a solid lubricant such as tungsten disulfide or molybdenum disulfide is blended in the cage material of the rolling bearing, so that the raceway surface of the rolling element, the inner member or the outer member is blended in the cage. A technique is shown in which a solid lubricant is supplied.
JP-A-63-246507 JP-A 63-282233

In addition to cages, solid lubricants can be blended in the constituent materials of spacers interposed in rolling bearings, but these cages and spacers blended with solid lubricants such as tungsten disulfide and molybdenum disulfide are extremely In addition, there is a problem that chipping and cracking are liable to occur when assembled into a rolling bearing by press fitting.
Further, even when the rolling bearing is in operation, there has been a problem that the thin portion of the cage breaks due to contact with the rolling elements. Regarding the spacer, since the outer peripheral portion is particularly sharp, for example, the outer peripheral portion is caught in an insertion port or the like for loading the spacer during operation of the bearing and is a brittle material, so that there is a problem that chipping occurs. In this case, the missing material lump may be caught between the rolling elements and the raceway surface, or the spacer may fall off.

  The present invention has been made in view of the above-described problems, and provides a rolling device and a rolling bearing that have good lubricity and can prevent operation stoppage due to loss of constituent materials.

  In order to solve the above problems, a rolling device according to a first aspect of the present invention includes an inner member having a raceway surface on an outer diameter surface, and a raceway surface facing the raceway surface of the inner member. An outer member disposed on the outer side of the direction member, a plurality of rolling elements disposed so as to be freely rollable between the both raceway surfaces, and a spacer interposed between the plurality of rolling elements. In the rolling device provided, the spacer sinters a sintered material containing a solid lubricant made of one or both of tungsten disulfide and molybdenum disulfide, and a sintered binder made of a metal or an alloy. It is characterized by being formed.

The rolling device according to a second aspect of the present invention is the rolling device according to the first aspect, wherein the spacer has a content of the solid lubricant per unit volume of 10 mass% to 60 mass%, and the spacer. On the surface other than the surface facing the rolling element, the content of the solid lubricant in the sintered material increases from the surface toward the inside.
Here, the state in which the content of the solid lubricant in the sintered material increases as it goes from the surface to the inside increases not only when the content of the solid lubricant increases continuously but also in a stepwise manner. Including cases. Examples of the case where the level is increased stepwise include, for example, a case where the spacer is formed of a plurality of layers having different solid lubricant contents. In this case, the solid lubricant content is higher in the inner layer. However, the solid lubricant content may be the same in the same layer.

  The rolling device according to claim 3 of the present invention is the rolling device according to claim 1 or 2, wherein the sintered binder is a metal made of one of a metal group consisting of tungsten, copper, iron, cobalt, tin, and nickel, At least one of an alloy composed of two or more of the metal group and an alloy composed of at least one of nitrogen, boron and oxygen which are non-metallic components and at least one of the metal group. It contains seeds.

  A rolling bearing according to a fourth aspect of the present invention is a rolling bearing comprising an inner ring, an outer ring, a rolling element, and a cage that forms at least one pocket and holds the rolling element in the pocket so as to freely roll. The cage is formed by sintering a sintered material containing a solid lubricant made of one or both of tungsten disulfide and molybdenum disulfide, and a sintered binder made of a metal or an alloy, The solid lubricant content per unit volume is 10% by mass or more and 60% by mass or less, and the content of the solid lubricant in the sintered material increases from the surface toward the pocket. And

  A rolling bearing according to a fifth aspect of the present invention is the rolling bearing according to the fourth aspect, wherein the sintered binder is a metal made of one of a metal group consisting of tungsten, copper, iron, cobalt, tin and nickel, and the metal group. And at least one of an alloy composed of at least one of nitrogen, boron and oxygen which are non-metallic components and at least one of the metal group. It is characterized by doing.

According to the rolling device of the present invention, the lubricity is excellent, and there is little risk of operation stop due to a lack of constituent materials.

Next, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a rolling bearing equipped with a cage 1 according to this embodiment, and FIG. 2 is a diagram showing the cage 1 according to this embodiment.
The rolling bearing 4 includes an outer ring 41, an inner ring 42, a ball 43 as a rolling element that is arranged to roll between the outer ring 41 and the inner ring 42, and a cage 1 that holds the ball 43 in a rollable manner, In addition to the cage 1, it has a known configuration.

The cage 1 according to the present embodiment is a short cylindrical member in which a plurality of pockets 1a for holding the balls 53 so as to be able to roll are provided at a predetermined interval in the circumferential direction, and includes a solid lubricant and a sintered binder. It is formed by sintering the binder material.
One or both of tungsten disulfide and molybdenum disulfide is used as the solid lubricant. These solid lubricants are excellent in lubricity and are easily transferred to the raceway surface and balls as a lubricating component even after sintering. Tungsten disulfide is excellent in heat resistance, but has a large specific gravity and tends to increase centrifugal force during rotation. On the other hand, molybdenum disulfide has a lower specific gravity than tungsten disulfide, but is inferior in thermal stability to tungsten disulfide. Therefore, it is preferable to select and use as appropriate according to the application. In addition to tungsten disulfide and molybdenum disulfide, graphite that can serve as a lubricant may be blended.

  As the sintering binder, one of metal components composed of tungsten, copper, iron, cobalt, tin and nickel, an alloy composed of two or more of the metal components, and nitrogen which is a non-metallic component, Any of alloys made of at least one of boron and oxygen and at least one of the metal components can be used. In particular, copper is excellent in strength, heat resistance and lubricity, and is inexpensive. When copper or iron is the main component, it is preferable to add another metal or non-metal component for the purpose of improving other characteristics. Addition of tungsten, cobalt, and nickel improves wear resistance, strength, and corrosion resistance.

  In the present embodiment, the content of the solid lubricant is 10% by mass or more and 60% by mass or less in any part, but the content of the solid lubricant is more in the axial center than in the axial end. Largely, in FIG. 1, the axial direction both ends 1b and 1b are 10 mass%, and the axial center part 1c is 60 mass%. Thus, by increasing the concentration of the solid lubricant toward the pocket 1a in contact with the ball 43, good lubricity can be obtained, and at a portion away from the pocket 1a, the concentration of the solid lubricant is decreased. In a portion where load is easily applied during operation or press-fitting, particularly in a thin axial end portion, there is little influence of embrittlement due to the blending of the solid lubricant, and sufficient strength is ensured. Note that if the solid lubricant content is less than 10% by mass, cracks occur after sintering, which is not preferable, and if it exceeds 60% by mass, sufficient strength cannot be ensured.

  Next, a manufacturing method of the cage 1 according to the present embodiment will be described with reference to FIG. First, pressure molding is performed using a molding machine including a concave mold 91 in which a cylindrical concave portion is formed and a convex mold 92 in which a convex portion having a shape that fits into the concave mold 91 is formed. At this time, in the concave mold 91, a powdery material blended with 10% by mass of solid lubricant, a powdery material blended with 60% by mass of solid lubricant, and a powdery material blended with 10% by mass of solid lubricant. The materials are sequentially filled, and materials having different blending amounts of the solid lubricant are alternately laminated. Thereafter, the convex mold 92 is pressed into the concave mold 91 to perform pressure molding. Next, the obtained molded product is subjected to heat treatment, and then the pocket 1a is formed by cutting, whereby the cage 1 is manufactured.

As described above, the rolling bearing 4 to which the cage 1 according to this embodiment is mounted has a long lubrication life because the cage 1 has sufficient strength and lubricity, and the ball 43 is damaged by the breakage of the cage 1. Occurrence of troubles such as occlusion of the bearing due to falling off or remaining damaged parts inside the bearing can be prevented.
In the present embodiment, two types of materials having different solid lubricant contents are used in the axial end portions 1b and 1b and the axial center portion 1c, but the present invention is not limited to this. Three types of materials having different values may be used. Also in this case, the content of the solid lubricant is increased from the axial end 1b toward the center in the axial direction.

In addition, the shape of the cage is not limited to the above-described shape, and may be a crown-shaped cage or the like.
(Second embodiment)
Next, a second embodiment of the present invention will be described.
FIG. 4 is a view showing the spacer 2 according to the present embodiment.
Although the rolling bearing 4 of this embodiment is not illustrated, it has substantially the same configuration as that of the first embodiment, and the spacer 2 is interposed between the balls 43, 43 instead of the cage 1. Is different. Hereinafter, the spacer 2 will be mainly described.

  The spacer 2 according to the present embodiment is a substantially cylindrical member whose both end faces are concave curved surfaces that receive the balls 43, and sinters a sintered material containing a solid lubricant and a sintered binder. Is formed. Since the kind of the sintering material that can be used is the same as that of the first embodiment, the details are omitted. The solid lubricant content is 10% by mass or more and 60% by mass or less in any part, but the content is larger in the central part 2b than in the outer peripheral part 2a. In FIG. The mass% and the center part 1b are 60 mass%. Thus, good lubricity can be obtained by increasing the content of the solid lubricant in the central portion 1 c in contact with the balls 43. At the same time, the outer peripheral portion 2b has a pointed shape that is easily damaged when inserted into the rolling bearing 4 or during operation. Therefore, the content of the solid lubricant is kept low, and the influence of the blending of the solid lubricant is sufficiently reduced. High strength can be ensured.

  Next, a method for manufacturing the spacer 2 according to the present embodiment will be described with reference to FIGS. First, pressure molding is performed using a molding machine including a concave mold 93 in which a cylindrical concave portion is formed and a convex mold 94 in which a convex portion that is shaped to fit into the concave mold 93 is formed. At this time, a partition member 95 is arranged in the concave mold 93, and a powdery material in which 10% by mass of a solid lubricant is blended in each space partitioned by the partition member 95 and a powder in which 60% by mass of the solid lubricant is blended. And filling the material. Thereafter, the partition member 95 is removed, and the convex mold 94 is pressed into the concave mold 93 to perform pressure molding. The columnar molded product obtained by the pressure molding is subjected to heat treatment, and then the end surface of the molded product is cut into a concave curved surface by cutting to produce the spacer 2.

As described above, the rolling bearing 4 in which the spacer 2 according to the present embodiment is interposed has a long lubrication life because the spacer 2 has sufficient strength and lubricity. Further, it is possible to prevent the occurrence of troubles such as biting of the balls 43 due to the damaged portion remaining inside the rolling bearing 4.
The spacer 2 described above uses two types of materials having different solid lubricant contents in the outer peripheral portion 2a and the central portion 2b, but the present invention is not limited to this. For example, as shown in FIG. You may use three types of materials from which content differs. Also in this case, the content of the solid lubricant increases from the surface toward the inside, and the content is 10% by mass in the outer peripheral portion 3a forming the surface, and the intermediate portion 3b inside the outer peripheral portion 3a. And 40% by mass, and 60% by mass in the central part 3c inside the intermediate part 3b.

Moreover, the ratio of the outer peripheral part 1a and the center part 1b is not particularly limited, but is set to a ratio that can ensure sufficient strength without impairing the lubricity.
Further, the application of the present invention is not limited to the rolling bearing 4 and can be applied to, for example, the ball screw device 5 shown in FIG. 7 and the linear motion guide device 6 shown in FIG.
7 includes a screw shaft (inner member) 52 having a spiral raceway groove 52a on the outer peripheral surface, and a nut (outer member) 51 having a spiral raceway groove 51a on the inner peripheral surface. And a plurality of balls (rolling elements) 53 interposed between the both raceway grooves 52a and 51a so as to be freely rollable, and the axis of the screw shaft 52 is rotated by either the screw shaft 52 or the nut 51. One moves linearly relative to the direction. And between the balls 53 and 53, the spacer 2 which concerns on this embodiment is interposed, and ball screw device 5 parts other than this spacer 2 are a well-known structure. Reference numeral 54 in the drawing denotes a circulator tube for accommodating the ball 53 that has rolled between the raceway grooves 52a and 51a and returning it again between the raceway grooves 52a and 51a.

  FIG. 8 is a view showing a part of the linear motion guide device 6 cut along the moving direction. The linear guide device 6 has a rectangular guide rail (inner member) 62 having rolling element rolling grooves a having an arc-shaped cross section in the axial direction on both side surfaces, and straddles the guide rail 62 so as to be relatively movable in the axial direction. And a slider (outer member) 61 having a substantially U-shaped cross section. On both inner side surfaces of the slider 61, there are provided rolling element rolling grooves having an arcuate cross section facing the rolling element rolling grooves of the guide rail 62, and the rolling element rolling grooves of the guide rail 62 and the slider 61 are rolled. A plurality of balls 63 as rolling elements are slidably loaded in a linear ball rolling space having a substantially circular cross section formed by the moving body rolling grooves. The above is a known configuration, and the spacer 2 similar to the above is interposed between the balls 63 and 63 in the linear guide device 6 having such a configuration.

  Thus, sufficient strength and lubricity can be obtained by using the spacer according to the present invention.

Next, examples of the present invention will be described.
In this example, first, the cage 1 shown in FIG. 2 and the spacer 2 shown in FIG. 4 were respectively produced as described above. Specifically, after performing pressure molding as described above, the molded product was sintered at 1200 ° C. for 1 hour in a nitrogen atmosphere. After that, the cage 1 was manufactured by cutting for the ball bearing of the reference number 608, and the spacer 2 was manufactured for the ball bearing of the reference number 6009, respectively. Moreover, the test piece of the holder | retainer and the spacer was also produced as a comparative example. The test pieces of these comparative examples have the same shape and sintering conditions as those of the examples, but the solid lubricant is uniformly dispersed throughout the material because the materials having different solid lubricant contents are not used ( 40% by mass). In both Examples and Comparative Examples, tungsten and copper were used as the metal or alloy, and tungsten disulfide was used as the solid lubricant.

Next, the test pieces of Examples and Comparative Examples produced as described above were incorporated in ball bearings having a nominal number 608 or a nominal number 6009, respectively. As a result of incorporating each test piece into 10 ball bearings, none of the test pieces of the examples were chipped or cracked. On the other hand, in the comparative example, chipping or cracking occurred at the time of incorporation with a 50% test piece.
Furthermore, a life test was performed on the ball bearings in which the test pieces of Examples and Comparative Examples were respectively incorporated. In the life test, the outer ring of the ball bearing is fixed to a test device (not shown) under an atmospheric condition of a vacuum degree of 10 ⁻⁴ Pa and a temperature of 300 ° C., a thrust load of 27 N is applied, and the inner ring is rotated at a rotational speed of 1200 / min. This was done by measuring the total number of rotations when the bearing was locked due to chipping or cracking of the test piece and the rotation stopped. The results are shown in Table 1.

表１に示すように、実施例の保持器１及びスペーサ２を用いた場合には総回転数が１０⁷台になるまで欠け又はクラックが発生しなかった。これに対し、比較例の保持器１及びスペーサ２を用いた場合には、総回転数が１０³台で欠け又はクラックが発生し、軸受が停止した。

As shown in Table 1, when the cage 1 and the spacer 2 of the example were used, no chipping or cracking occurred until the total number of revolutions reached 10 ⁷ . On the other hand, when the cage 1 and the spacer 2 of the comparative example were used, chipping or cracking occurred at a total rotational speed of 10 ³ units, and the bearing stopped.

  From these facts, it was confirmed that the cage and spacer according to the present invention have sufficient strength and are less likely to be chipped or cracked when assembled into a bearing or during operation.

It is a figure which shows the rolling bearing equipped with the holder | retainer which concerns on 1st embodiment. It is a figure showing a maintenance machine concerning a first embodiment. It is a figure explaining the manufacturing method of the cage concerning a first embodiment. It is a figure which shows the spacer which concerns on 2nd embodiment. It is a figure explaining the manufacturing method of the spacer concerning a second embodiment. It is a figure which shows the other example of the spacer which concerns on 2nd embodiment. It is a figure which shows the ball screw apparatus using the spacer which concerns on this invention. It is a figure which shows the linear motion guide apparatus using the spacer which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cage 1a Pocket 2 Spacer 4 Rolling bearing 41 Outer ring 42 Inner ring 43 Ball 5 Ball screw device 51 Nut 51a Track groove 52 Screw shaft 52a Track groove 53 Ball 6 Linear motion guide device 61 Slider 62 Guide rail 63 Ball

Claims (5)

An inner member having a raceway surface on the outer diameter surface, an outer member having a raceway surface opposite to the raceway surface of the inner member and disposed outside the inner member, and the both raceway surfaces In a rolling device comprising a plurality of rolling elements arranged to be freely rollable and a spacer interposed between the plurality of rolling elements,
The spacer is formed by sintering a sintered material containing a solid lubricant composed of one or both of tungsten disulfide and molybdenum disulfide and a sintered binder composed of a metal or an alloy. A rolling device characterized by.   In the spacer, the content of the solid lubricant per unit volume is 10% by mass or more and 60% by mass or less, and the surface of the spacer other than the surface facing the rolling element is directed from the surface toward the inside. The rolling device according to claim 1, wherein the content of the solid lubricant in the sintered material is high.   The sintered binder includes a metal composed of one of a metal group consisting of tungsten, copper, iron, cobalt, tin and nickel, an alloy composed of two or more of the metal group, and non- It contains at least 1 sort (s) of the alloy which consists of at least 1 sort (s) of at least 1 sort (s) of said metal group and at least 1 sort (s) of nitrogen, boron, and oxygen which are metal components. Rolling device. In a rolling bearing comprising an inner ring, an outer ring, a rolling element, and a cage that forms at least one pocket and holds the rolling element in the pocket so as to roll freely,
The cage is formed by sintering a sintered material containing a solid lubricant made of one or both of tungsten disulfide and molybdenum disulfide, and a sintered binder made of a metal or an alloy,
The solid lubricant content per unit volume is 10% by mass or more and 60% by mass or less, and the content of the solid lubricant in the sintered material increases from the surface toward the pocket. Rolling bearing.   The sintered binder is a metal composed of one of a metal group consisting of tungsten, copper, iron, cobalt, tin, and nickel, an alloy composed of two or more of the metal group, and a non-metallic component. 5. The rolling bearing according to claim 4, comprising at least one of an alloy composed of at least one of nitrogen, boron, and oxygen and at least one of the metal group.

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