JP2000179557A - Roller bearing filled with polymer containing lubricant, and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roller bearing filled with a polymer containing a lubricant capable of surely maintaining the smooth rotation for a long time, and its manufacturing method. SOLUTION: In a roller bearing 1 filled with a polymer containing a lubricant in a space formed of an outer ring 2, an inner ring 3 and a rolling element 4, the roller bearing 1 filled with the polymer containing the lubricant is filled with a polymer 6 containing the lubricant through a grease film 5 of 10-1000 μm in thickness formed on an inner circumferential surface of at least the outer ring 2 of the roller bearing 1, an outer circumferential surface of the inner ring 3, and a surface of the rolling element 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing filled with a lubricant-containing polymer and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, a space formed by an outer ring, an inner ring, and a rolling element of a rolling bearing is filled with lubricating oil or grease for imparting lubricity. However, since these lubricating oils and greases are liquid or semi-solid substances, they are always sealed with a seal plate or the like in order to prevent them from scattering or fluidizing during rotation of the bearing. For this reason,
It was difficult to use these lubricants and grease in small special bearings.

[0003] Therefore, it has been proposed to fill a space between the outer ring, inner ring and rolling elements of a bearing with a polymer containing a lubricant. For example, Japanese Patent Publication No. 63-23239 discloses that grease and polyethylene are used. It is disclosed that a lubricant-containing polymer (plastic grease) is filled in a space formed by an outer ring, an inner ring, and a rolling element of a bearing.
In this lubricant-containing polymer-filled rolling bearing, the lubricant-containing polymer gradually releases grease, which is a lubricating component taken in with the rotation of the bearing, to maintain long-term lubrication. However, in this type of lubricant-containing polymer-filled rolling bearing, the lubricant-containing polymer is usually filled so that the space between the outer ring and the inner ring is filled except for the space occupied by the rolling elements. The polymer hinders the rotation of the rolling elements, and the abrasion powder of the lubricant-containing polymer generated with the rotation of the bearings enters the gaps between the rolling elements and the inner and outer rings, causing the so-called biting phenomenon. Sometimes vibrated, and the function as a bearing was greatly reduced. In addition, the temperature of the bearing may be increased accordingly.

In order to solve such a problem, Japanese Patent Laid-Open Publication No. Hei 8-31652 discloses a method of forming a film made of a lubricating component between a cage and a rolling element prior to filling a lubricant-containing polymer. Proposed to avoid direct contact between the lubricant-containing polymer and the rolling elements.

[0005]

However, in a rolling bearing in which the lubricating component film is interposed, there is no specification of the type of the lubricating component and no regulation on the film thickness, and the effect of improving the lubricating performance may not be obtained. Was. In particular, when lubricating oil is selected as the lubricating component, a thick film cannot be formed,
The effect of improving the lubricating performance was sometimes insufficient. An object of the present invention is to solve the above problems, that is, to provide a lubricant-containing polymer-filled rolling bearing capable of reliably maintaining smooth rotation for a long period of time, and an object of the present invention to provide a manufacturing method thereof. .

[0006]

In order to achieve the above object, a first aspect of the present invention provides a rolling bearing in which a space defined by an outer ring, an inner ring and rolling elements is filled with a lubricant-containing polymer. In the rolling bearing, at least the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring and the surface of the rolling element is filled with the lubricant-containing polymer via a grease coating having a thickness of 10 to 1000 μm. Features. Further, in order to achieve the same object, the invention according to claim 2 is that, after assembling the rolling bearing, at least the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring and the surface of the rolling element have a thickness of 10 to 1000.
A grease film is formed so as to have a thickness of μm, and then the lubricant-containing polymer is filled in a space formed by the outer ring, the inner ring and the rolling elements and solidified.

A lubricant filled polymer bearing according to the present invention uses grease for forming a coating and has a thickness of 1 g / m.
By setting the thickness to 0 to 1000 μm, the effect of improving the lubricating performance can be reliably obtained. Also, by using grease, a thick film of about 1000 μm can be formed, and a large clearance can be provided between the lubricant-containing polymer and the rolling elements and the inner and outer rings, so that smooth rotation can be more reliably performed. Is obtained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. The present invention is applicable to various types of rolling bearings. For example, FIG. 1 is a cross-sectional view showing a ball bearing. In the ball bearing 1, a grease film 5 is formed on an inner peripheral surface of an outer ring 2, an outer peripheral surface of an inner ring 3, and a surface of a ball 4 as a rolling element. Further, a lubricant-containing polymer 6 is filled in a space formed by the outer ring 2, the inner ring 3, and the balls 4 on which the grease coating 5 is formed. Therefore, the lubricant-containing polymer 6 does not directly contact the outer ring 2, the inner ring 3 and the balls 4 due to the presence of the grease coating 5, and does not hinder the rotation of the balls 4 and the like. The grease coating 5 is a ball 4
Is formed also in the gaps between the outer ring 2 and the inner ring 3, thereby preventing the wear powder of the lubricant-containing polymer 6 from entering these gaps. Further, the lubricant-containing polymer 6 gradually releases the lubricating component taken in with the rotation of the ball bearing 1,
Maintain long-term lubrication.

As described above, since the grease film 5 is interposed between the lubricant-containing polymer 6 and the constituent parts of the ball bearing 1, the ball bearing 1 can smoothly rotate with low torque over a long period of time from the initial operation thereof. Can be done.

Further, the present invention can be applied to a self-aligning roller bearing 11 as shown in FIG. The self-aligning roller bearing 11 has a structure in which the rollers 14 as the rolling elements can be aligned, and accordingly, the entire bearing can be aligned. More specifically, the self-aligning roller bearing 11 is a cage in which barrel-shaped rollers 14 arranged in two rows between the inner ring 13 and the outer ring 12 and alternately arranged in the radial direction are integrally formed. A guide wheel 18, which is held by the retainer 17 and guides the rollers 14 between the retainer 17 and the inner ring 13, is arranged concentrically with the retainer 17. Further, a grease coating 15 is formed on the outer peripheral surface of the inner ring 13 and the inner peripheral surface of the outer ring 12, the surface of the rollers 14 and the surfaces of the guide wheels 18, and further, a void existing between the inner ring 13 and the outer ring 12. Inner ring 13
However, the gap between the outer end face of the roller 14 and the gap between the inner end face of the roller 14 and the guide wheel 18 are provided with a lubricant-containing polymer 16.
Are respectively filled.

Usually, in the spherical roller bearing 11,
The inner end surface of the roller 14 comes into sliding contact with the guide wheel 18, and the bearing torque increases and the bearing temperature increases. However, in the present invention, the surfaces of the rollers 14 and the guide wheels 18 are also coated with the grease coating 1.
Since the film 5 is formed, the contact resistance is reduced, and an increase in bearing torque and an increase in temperature of the bearing can be effectively suppressed.

The method for filling the lubricant-containing polymers 6, 16 is not particularly limited, but it is preferable to use an injection molding method.
The reason will be described below. In the present invention, a lubricant-containing polymer is filled after forming a grease coating on the surfaces of the rolling elements, the inner ring, and the outer ring. At that time, if the compatibility between the lubricant-containing polymer and the grease is high, the molten resin of the lubricant-containing polymer may take in the grease and solidify. Grease coating after solidification is uneven,
Problems such as a decrease in film thickness occur. The injection molding method can fill all corners of the filling space in a shorter time than other methods, so that the grease can be minimized.

Further, according to the injection molding method, a part of the grease is pushed to the corner of the filling space by the extrusion pressure, and a grease pool is formed. As a result, with the rotation of the bearing, the grease is gradually released from the grease pool to extend the lubrication life. FIG. 3 is a view of the self-aligning roller 10 shown in FIG. 2 viewed from the end face side (however, the inner ring flange is shown by a broken line for simplicity). With the filling, a part of the grease coated on the surface of the rollers 14 and the like moves to the corners of the filling space to form a grease reservoir 15a, and between the side surface of the rollers 14 and the inner race 13 and the outer race 12. It is possible to suppress the formation of the edge portion of the formed lubricant-containing polymer 16. By eliminating the edge portion, it is possible to prevent the edge portion from being caught between the outer ring 12 and the inner ring 12 and the side surface of the inner ring 12 and 14 during rotation of the bearing, thereby preventing damage and increasing the temperature.

4 and 5 in the injection molding method.
As shown in the figure, two divided bodies 30 divided into two right and left,
A mold composed of 31 is used. Both divided bodies 30, 3
1, a concave portion 32 in which the outer ring 12 is fitted, a concave portion 33 in which the inner ring 13 is fitted, and a brim portion 34 fitted between the inner ring 13 and the outer ring 12 from outside are formed. Collar part 3
4 has a surface along the outer end surface of the roller 14, a surface along the peripheral surface of the fall prevention collar 19 of the inner ring 13, and a surface along a surface outside the track of the inner peripheral surface of the outer ring 12. . Therefore,
The flanges 34 of each of the divided bodies 30 and 31 are fitted from the side surfaces of the bearing until the front end surface thereof contacts the outer end surface of the roller 14 between the inner ring 13 and the outer ring 12 so that each surface of the flange portion 34 The outer ring 1 is in contact with the corresponding surfaces of the
The outer peripheral surface and the side surface of the inner ring 1 are fitted, and the inner peripheral surface and the side surface of the inner ring 1 are fitted into the concave portion 33. Further, a gate 35 is provided on the flange 34 of one of the divided bodies 30. The gate 35 is a pin point gate, and the number of the rollers 14 is equal to the number of the rollers 14 in the roller row at intervals corresponding to the installation intervals of the rollers 14 in the roller row along the outer peripheral line of the annular portion of the cage 17. It is provided. When the divided body 30 is mounted on the bearing, the gate 35 is arranged at a position between the adjacent rollers 14 in the roller row on which the divided body 30 is mounted (here, the roller row on the left side in the figure). To be done.

The base end of each gate 35 is a disk-shaped runner 36.
And the parting line of the mold (P.
L. A sprue (not shown) is provided in a portion outside the parentheses) at a position which is the center of the shaft of the bearing. Therefore, the molten lubricant-containing polymer introduced into the sprue of the mold from the injection molding machine enters the runner 36, is spread in a disk shape, and is introduced into the bearing from all the gates 35. Then, the molten lubricant-containing polymer moves in the bearing as shown by the arrow in the figure. That is, first, as shown in FIG. 4, the molten lubricant-containing polymer is supplied from the tip of the gate 35 to the rollers 1 in the left column in the figure.
4, and a part thereof moves between the holding part 17 a on the left side of the holder 17 and the outer ring 12 to reach the space A between the annular part of the holder 17 and the outer ring 12. In addition, a part of the outer end surface of the holding portion 17a of the holder 17 and the
And part of which is a collar 1 for preventing the inner ring 13 from falling off.
9 enters the space B between the inner side surface and the outer end surface of 14,
Other than that, it moves between the holding portion 17a and the track 13a of the inner race 13 and enters the space C between the guide wheel 18 and the inner end surface of the guide wheel 18. The molten lubricant-containing polymer that has reached the space A then enters between the right-hand row particles 14 in the figure, as shown in FIG. Move between. A part thereof moves between the outer end face of the holding portion 17b and the flange portion 34 of the mold and enters the space D between the inner ring 13 and the collar 19 for preventing the inner ring 13 from falling off. Other than that,
It moves between the holding portion 17b and the track 13a of the inner ring 13 and enters the space E between the guide wheel 18 and the inner end face of the point 14.
The molten lubricant-containing polymer that has reached the space A is a roller 1
4 and the space F between the annular portion of the retainer 17. In the above-mentioned injection molding, for example, an injection molding machine described in JP-A-8-309793 by the present applicant can be suitably used.

As shown in FIG. 2, by removing the mold after performing the injection molding in this manner, the outer ring 12,
A grease coating 15 is formed on the surfaces of the inner ring 13 and the rollers 14, and a lubricant-containing polymer 16 is filled and solidified in the inner space of the bearing, that is, between the spaces A to F and the adjacent rollers 14 in each row. The obtained self-aligning roller bearing 10 is obtained. When the compatibility between the lubricant-containing polymer and the grease forming the coating is low, the method is not limited to the injection molding method.For example, the unsintered lubricant-containing polymer may be formed in the inner space of the bearing coated with the grease. After filling, a method of solidifying the lubricant-containing polymer by heating, melting, and cooling, so-called heat molding, is also possible.

Further, the present invention can be applied to an angular ball bearing having a structure shown in FIG. That is, the angular ball bearing 40 has a predetermined contact angle between the inner ring 41 and the outer ring
Is held by a crown-shaped retainer 44, grease (not shown) is further applied to the surface of the ball 43, and the outside thereof is filled with a lubricant-containing polymer 45. Further, the lubricant-containing polymer 45 is provided between the inner ring 41 and the gap C1 (for example, 0.1 mm).
5mm) is filled to form. The angular ball bearing 40 is manufactured using jigs A and B as shown in FIG. Each of the jigs A and B is provided with one vertically formed gap forming ring protrusion 51 on the surface of the backing plate 50 which is pressed against the side surface of the inner ring 41 or the outer ring 42. The projection length L of these ring projections 51 is
Of the raceway groove 41b from the end surface (side surface) of the outer peripheral surface 41a
It is almost the same as the length to the side end. The gap C1 is adjusted by the thickness of the ring projection 51. Note that the backing plate 50 is a plate on which the gap forming ring protrusion 51 is protruded,
The flat plates are formed integrally by fixing screws 52. The molding is performed by filling the unsintered lubricant-containing polymer with the jig B down, and performing heat molding.

In each of the above rolling bearings, since the grease is semi-solid, a thick coating can be formed. In the present invention, this grease coating is formed to a thickness of 10 to 1000 μm.
It is preferable that the film thickness is as follows. Grease coating is 10μm
If it is less than 3, the effect of improving the lubrication life will be insufficient. From the viewpoint of ensuring clearance for smooth rotation and ensuring lubrication life, it is preferable to make the grease coating thicker within the above range, but if the thickness exceeds 1000 μm, the lubricant-containing polymer and each part of the bearing (for example, the outer ring The distance between the peripheral portion and the outer peripheral portion of the inner ring becomes unnecessarily large, and the sealing performance against foreign matters such as dust and water is deteriorated. Further, if the amount of the coated grease is too large, for example, when the bearing is manufactured by injection molding, the portion of the internal space of the bearing occupied by the part of the grease pressed by molding increases. As a result, for example, in the bearing shown in FIG.
The space between the outer end surfaces of the lubricant 4 is not completely filled with the lubricant-containing polymer 16, and in some cases, the possibility of occurrence of a defective filling such as an exposed cage 17 is increased. The method of forming the grease film is not particularly limited, for example,
There is a method in which after a small amount of grease is filled in the bearing, the bearing is rotated to form a grease coating on the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring, and, in some cases, the surface of the rolling element. Another method is to dissolve the grease in a solvent that dissolves the base oil and disperse the thickener at an appropriate concentration, then immerse it in the solution, and then dry it to remove the solvent. By doing so, a grease coating can be formed. In addition, it is preferable that the bearing is degreased and washed before the formation of the grease coating.

In the present invention, the materials of the grease coating and the lubricant-containing polymer are not particularly limited, but preferred examples will be described below. The lubricant-containing polymer used in the present invention is polyethylene, polypropylene,
Synthetic resins selected from the group of polyolefin resins having basically the same chemical structure such as polybutylene and polymethylpentene, and paraffinic hydrocarbon oils such as poly-α-olefin oils and naphthenic hydrocarbon oils as lubricants ,
Mineral oil, ether oil such as dialkyl diphenyl ether oil, ester oil such as phthalate ester, etc., either alone or mixed in the form of a mixed oil, heated and plasticized above the melting point of the resin, then cooled The lubricant may be made into a solid state, and may be a lubricant to which various additives such as an antioxidant, a rust inhibitor, an antiwear agent, a defoaming agent, and an extreme pressure agent are added in advance. The composition ratio of the above-mentioned lubricant-containing polymer is 10 to 10 polyolefin resins with respect to the total weight.
50% by weight, 90-50% by weight of lubricant. If the content of the polyolefin resin is less than 10% by weight, a certain level of hardness and strength cannot be obtained, and it becomes difficult to maintain the initial shape when a load is applied due to rotation of the bearing, etc. There is a high possibility that troubles such as desorption from the device will occur. On the other hand, when the amount of the polyolefin resin exceeds 50% by weight (that is, when the amount of the lubricant is less than 50% by weight), the supply of the lubricant to the bearing is reduced, and the life of the bearing is shortened.

The above synthetic resin groups have the same basic structure but different average molecular weights, ranging from 700 to 5 × 10 ⁶ . When used, the average molecular weight is 700-1 × 10
Classified as ⁴ waxes, average molecular weight 1 × 10 ⁴ ~
1 × 10 of relatively low molecular weight of ⁶ ones, average molecular weight 1 × 10 ⁶
Those having an ultrahigh molecular weight of up to 5 × 10 ⁶ are used alone or in combination as necessary. For example, a combination of a relatively low molecular weight and a lubricant can provide a lubricant-containing polymer with some mechanical strength, lubricant supply capacity, and oil retention. Also, if a part of this relatively low molecular weight is replaced with a wax classified, the difference in molecular weight between the wax classified and the lubricant is small, so the affinity with the lubricant is increased, As a result, the oil retaining property of the lubricant-containing polymer is improved, and the lubricant can be supplied for a long period of time. However, on the other hand, the mechanical strength decreases.
As the wax, in addition to polyolefin resins such as polyethylene wax, hydrocarbon waxes having a melting point in the range of 100 to 130 ° C. or more (for example, paraffinic synthetic wax) can be used. On the other hand, if some of the relatively low molecular weight products are replaced with ultra high molecular weight ones, the difference in molecular weight between the ultra high molecular weight type and the lubricant will be large, and the affinity with the lubricant will be low. As a result, the oil retention is reduced, and the oozing of the lubricant from the lubricant-containing polymer is accelerated. Thereby, the time to reach the limit amount of the lubricant that can be supplied from the lubricant-containing polymer is shortened, and the life of the bearing is shortened. However, the mechanical strength is improved. In consideration of the balance of moldability, mechanical strength, oil retention, and lubricant supply, the composition ratio of the lubricant-containing polymer is 0 to 5% by weight classified into wax, and 8 to 5% in relatively low molecular weight. 48% by weight, 2 to 15% by weight of ultra high molecular weight, and a total of 10 to 50% by weight of three resins (the remainder is
50% by weight) is practically suitable.

As an index of mechanical strength, the hardness [HD _A (durometer hardness using scale A)] of the lubricant-containing polymer is preferably in the range of 65 to 85, more preferably in the range of 70 to 80. Is more preferable. If the hardness [HD _A ] is less than 65, the bearing is weak in strength and may be damaged by rotation of the bearing. On the other hand, when the hardness [HD _A ] exceeds 85, the force for restraining the rolling elements is too large, thereby increasing the torque of the bearing or increasing the heat generated by the rotation of the bearing to increase the temperature of the bearing. There is a risk of becoming. In order to improve the mechanical strength of the lubricant-containing polymer, the following thermoplastic resin and thermosetting resin may be added to the above-mentioned polyolefin-based resin. As the thermoplastic resin, resins such as polyamide, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, polyether sulfone, polyether ether ketone, polyamide imide, polystyrene, and ABS resin can be used. As the thermosetting resin, each resin such as an unsaturated polyester resin, a urea resin, a melanin resin, a phenol resin, a polyimide resin, and an epoxy resin can be used. These resins may be used alone or as a mixture.

Similarly, in order to improve the mechanical strength,
A filler may be added. For example, calcium carbonate whiskers, magnesium carbonate whiskers, potassium titanate whiskers, inorganic whiskers such as aluminum borate whiskers, glass fibers, metal fibers, inorganic fibers such as carbon fibers, and those obtained by braiding them into a cloth, or Inorganic powders such as carbon black and graphite powders, organic fibers such as aramid fibers and polyester fibers, and braided cloths thereof may be added.

In order to disperse the polyolefin resin and the other resin in a more uniform state, a suitable compatibilizer may be added as needed. Further, in order to prevent deterioration of the polyolefin resin due to heat, N, N '
Anti-aging agents such as -diphenyl-p-phenyldiamine and 2,2'-methylenebis (4-ethyl-6-t-butylphenol);
-Hydroxy-4-n-octoxybenzophenone, 2
An ultraviolet absorber such as-(2'-hydroxy-3'-tert-butyl-5'-methyl-phenyl) -5-chlorobenzotriazole may be added.

The amount of the additives other than the above-mentioned polyolefin resin and the lubricant is preferably 20% by weight or less of the total amount of the forming raw material in order to maintain the lubricant supply capacity. .

As the polymer material that can be used in the present invention, in addition to those based on the polyolefin resin described above, any thermoplastic resin that can be injection-molded can be used. For example, polyester elastomers and the like can be used to increase the amount. In addition to the thermoplastic resin, an injection-moldable thermosetting resin such as a polyurethane or a polyurea elastomer can be used. In the case of polyurethane, grease is used as a lubricant and becomes a reaction raw material. The urethane prepolymer containing an isocyanate group and the amine-based curing agent are mixed uniformly with the grease, and then the two mixtures are further mixed and filled into bearings, and if necessary, heated to react. And hardened with grease contained. In the case of polyurea, an amine component consisting of a mixture of an aromatic polyamine compound and an aromatic diamine containing a soft segment in the molecular chain is uniformly mixed with a lubricating oil compatible therewith or a grease based on the lubricating oil. The resulting mixture is further mixed with a polyisocyanate component, mixed, filled, heated and reacted as needed, and cured with a lubricant.

On the other hand, the type of grease is not limited, but it is more preferable to consider the affinity with the resin forming the above-mentioned lubricant-containing polymer and the lubricant. As described above, in the present invention, the lubricant-containing polymer is once in a molten state at the time of filling, but at that time, the resin and the lubricant constituting the lubricant-containing polymer are in a state of being compatible with each other, and the resin is It is in a state where other components having compatibility with it are most easily taken in. Therefore, if the grease and the resin deposited on the surface of the rolling elements are compatible,
Grease is taken into the molten resin, and the possibility that the lubricant-containing polymer solidifies by contacting the rolling elements is increased.As a result, the rotation of the rolling elements is restricted, and the torque reduction effect of the grease film is not so large. In some cases, it will not work.

Therefore, in the present invention, it is preferable that the combination of the resin and the lubricant forming the lubricant-containing polymer and the grease has low compatibility. For example, when the resin of the lubricant-containing polymer is a polyolefin resin such as polyethylene, since the polyolefin resin is a hydrocarbon having a low polarity, the lubricant which can be contained alone at a high concentration has a relatively similar polarity. Suitable are low hydrocarbon compounds such as mineral oil, poly-α-olefin oil, phenyl ether with a long hydrocarbon chain such as octadecyl diphenyl ether, and naphthalene with a long hydrocarbon chain such as eicosyl naphthalene. . Therefore,
In the case of a lubricant-containing polymer composed of a combination of hydrocarbon compounds having a low polarity, as grease for a coating,
Fluorine grease that has almost no compatibility with hydrocarbon compounds (thickener: PTFE, base oil: perfluoropolyether), silicon grease (thickener: lithium soap,
Base oil: phenylmethylpolysiloxane, dimethylpolysiloxane), fluorosilicone grease (thickener:
Lithium soap, base oil: fluorosilicone) and the like are most preferred. Also, other hydrocarbon-based ester greases (thickeners: urea, lithium soap, etc.) based on ester oils having low compatibility due to their high polarity, such as pentaphenylether and tetraphenylether. Polyphenyl ether-based greases based on polyphenyl ether (thickener: bentonite, etc.) can also be used.

When the lubricant-containing polymer resin is a highly polar hydrocarbon compound such as polyester elastomer, polyurea elastomer or polyurethane, it is compatible with the above-mentioned hydrocarbon compound. Most preferred are fluorine grease, silicone grease, fluorosilicone grease, etc., which have almost no odor. Contrary to the above, hydrocarbon-based greases have a low polarity such as mineral oil having low polarity, poly-α-olefin oil, phenyl ether having a long hydrocarbon chain such as octadecyl diphenyl ether, and elongation such as eicosyl naphthalene. It is possible to use those having low compatibility with naphthalene having a hydrocarbon chain as a base oil and urea, lithium soap or the like as a thickener.

As described above, the lubricant-containing polymer-filled rolling bearing of the present invention has a grease coating formed on the surfaces of the rolling elements, the inner ring, and the outer ring. The state in which the grease coating is interposed between the rolling element, the inner ring, the outer ring and the solidified lubricant-containing polymer is maintained. Thus, since the rolling elements are not restrained by the lubricant-containing polymer and rotate smoothly and have a low torque, the heat generation due to the rotation of the bearings is reduced, so that the use at a higher speed is possible. Further, when the compatibility between the lubricant-containing polymer and the grease is low, the incorporation of grease by the resin at the time of filling the lubricant-containing polymer is suppressed, and a thicker and more uniform grease coating is formed.

[0030]

The present invention will be further described with reference to the following examples. However, the present invention is not limited to the following.

Example 1 10% by weight of high density polyethylene
Then, a resin containing 12.5 wt% of ultra-high molecular weight polyethylene and 2.5 wt% of polyethylene wax and 75 wt% of mineral oil were mixed to prepare a lubricant-containing polymer. Further, after the self-aligning roller bearing 22331 is degreased and cleaned, the grease (ester grease, base oil: polyol ester, thickener: lithium soap) is immersed in a solution diluted with petroleum benzene, taken out, and left. By this, the film thickness 50μ on the bearing surface
m of grease coating was formed. Then, as shown in FIGS. 4 and 5, with the bearing held in a mold, a lubricant-containing polymer having the above composition was injection molded (insert molded) to produce a test bearing. The lubricant-containing polymer was injected from one side, and the gate was provided between each roller (pinpoint gate). Further, an injection molding machine is disclosed in Japanese Patent Application Laid-Open No. 8-309.
No. 793 (improved hopper) was used.

Example 2 A test bearing was produced in the same manner as in Example 1 except that the coated grease was changed to a silicon-based grease (base oil: phenylmethylpolysiloxane, thickener: lithium soap).

Example 3 A test bearing was produced in the same manner as in Example 1 except that the coated grease was changed to a fluorine-based grease (base oil: perfluoropolyether, thickener: PTFE).

Example 4 A test bearing was produced in the same manner as in Example 1, except that the coated grease was changed to a mineral oil-based grease (thickener: lithium soap).

Comparative Example 1 A test bearing was produced in the same manner as in Example 1, except that mineral oil was used instead of grease. The thickness of the mineral oil was 3 μm.

(Rotation test) For each of the above test bearings, F
Apply a load of r = 500 kgf and increase the rotation speed from 600rpm to 100rpm.
The number of revolutions was increased and held for 24 hours at each revolution number, and the revolution number at which breakage such as cracks occurred in the lubricant-containing polymer was examined. Table 1 shows the results.

[0037]

[Table 1]

As is clear from the results shown in Table 1, the test bearings of Examples 1 to 4 in which the grease coating was formed had a lower temperature rise due to the rotation of the bearing than the test bearing of Comparative Example 1 coated with mineral oil. As a result, it can be seen that the number of damaged rotations is greatly improved.

(Example 5) An angular ball bearing "30TAC62B" for supporting a ball screw manufactured by Nippon Seiko Co., Ltd. was used as a test bearing, and the same grease as in Example 1 was coated on the surface of the rolling element to a thickness of 50 µm. Then, the same lubricant-containing polymer as in the example was filled by heat molding using a jig shown in FIG. 7 to produce a test bearing.

(Comparative Example 2) A test bearing was produced in the same manner as in Example 5, except that mineral oil was used instead of grease. The thickness of the mineral oil was 3 μm.

(Rotation test 2) Example 5 and Comparative example 2
Each of the three test bearings (combination of DBDs) was mounted, and a rotation test was performed to check the number of failed rotations. On the opposite side of the shaft, two bearings (DT
The bearings of each group were mounted so that a load of 500 kgf was applied to the bearings from inside by pretension. Rotation speed is 600r
pm, increase by 100rpm, 2 for each rotation speed
After holding for 4 hours, the number of revolutions at which cracks and the like occur in the lubricant-containing polymer was examined. Table 2 shows the results.

[0042]

[Table 2]

From Table 2, it can be seen that the formation of the grease coating greatly increases the number of rotations at break.

Example 6 A test bearing was produced in the same manner as in Example 1 except that the thickness of the grease was changed to 10 μm.

Example 7 A test bearing was produced in the same manner as in Example 1 except that the thickness of the grease was changed to 1000 μm.

Comparative Example 3 A test bearing was produced in the same manner as in Example 1, except that the thickness of the grease was changed to 5 μm.

Comparative Example 4 A test bearing was produced in the same manner as in Example 1, except that the thickness of the grease was changed to 1200 μm.
By the injection molding, the space between the outer end faces of the rollers could not be completely filled with the lubricant-containing polymer in the filling shape shown in FIG. 2, and the cage was exposed at three places.

(Rotation Test 3) Rotation tests similar to those performed in Examples 1 to 4 and Comparative Example 1 were performed on Examples 6 and 7 and Comparative Examples 3 and 4. Table 3 shows the test results.

[0049]

[Table 3]

From Table 3, it can be seen that good lubrication can be obtained by forming the grease coating so that the film thickness is in the range of 10 to 1000 μm. Comparative Example 4 was broken at a low rotation speed due to poor filling.

[0051]

As described above, the lubricating polymer-filled rolling bearing of the present invention has improved lubricating performance by using grease for forming a film and by regulating its film thickness to 10 to 1000 μm. Obtained reliably. Also,
By using grease, a thick film of about 1000 μm can be formed, the clearance between the lubricant-containing polymer and the rolling elements and the inner and outer rings can be increased, and smooth rotation can be more reliably obtained. Can be

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a principal part showing one embodiment (a ball bearing) of a lubricant-containing polymer-filled rolling bearing according to the present invention.

FIG. 2 is a sectional view of a main part showing another embodiment (a self-aligning roller bearing) of a lubricant-containing polymer-filled rolling bearing according to the present invention.

3 is a view (part) of the spherical roller bearing shown in FIG. 2 as viewed from the end face side.

FIG. 4 is a view for explaining a filling process of a lubricant-containing polymer by an injection molding method.

FIG. 5 is a diagram for explaining a filling process of a lubricant-containing polymer by an injection molding method.

FIG. 6 is a sectional view of a main part showing another embodiment (angular ball bearing) of a lubricant-containing polymer-filled rolling bearing according to the present invention.

FIG. 7 is a view for explaining a method of manufacturing the angular ball bearing shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ball bearing 2 Outer ring 3 Inner ring 4 Ball 5 Grease coating 6 Lubricant-containing polymer 10 Self-aligning roller bearing 12 Outer ring 13 Inner ring 14 Roller 15 Grease coating 16 Lubricant-containing polymer 30, 31 Mold divided body 40 Angular ball bearing 41 Inner ring 42 Outer ring 43 Ball 45 Lubricant-containing polymer

Claims (2)

[Claims] 1. A rolling bearing in which a space formed by an outer ring, an inner ring and a rolling element is filled with a lubricant-containing polymer, wherein at least the inner peripheral surface of the outer ring of the rolling bearing, the outer peripheral surface of the inner ring and the rolling element. 10-100 formed on the surface
A lubricant-filled polymer-filled rolling bearing, wherein the lubricant-containing polymer is filled via a grease film having a thickness of 0 μm. 2. After assembling the rolling bearing, at least 10 to 10 are applied to the inner peripheral surface of the outer ring, the outer peripheral surface of the inner ring, and the surface of the rolling element.
Forming a grease coating to a thickness of 00 μm,
Next, the lubricant-containing polymer is filled in a space formed by the outer ring, the inner ring, and the rolling elements, and solidified, thereby manufacturing a lubricant-containing polymer-filled rolling bearing.