JP2000345179A - Lubricant supply composition and rolling bearing filled therewith - Google Patents

Abstract

(57) [Problem] To provide a lubricant supply composition capable of ensuring long-term lubrication and a rolling bearing filled with the same. A lubricant supply composition comprising a synthetic resin solidified in a state containing a lubricant and supplying a lubricant to an adjacent member to be lubricated by gradually oozing out the lubricant contained therein, A lubricant supply composition comprising a solid lubricant, and a rolling bearing filled with the lubricant supply composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant supply composition comprising a synthetic resin containing lubrication in advance, and an improvement of a rolling bearing filled with the lubricant supply composition.

[0002]

2. Description of the Related Art Generally, a space (hereinafter, referred to as an internal space) formed by an outer ring, an inner ring, a rolling element, and a retainer of a rolling bearing is filled with lubricating oil or grease to provide lubrication. I have. 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 has been difficult to use these lubricants and grease in small special bearings.

Therefore, it has been proposed that a polymer containing a lubricant is filled in the inner space of the bearing. For example, US Pat. Nos. 3,729,415, 3,547,819, and 35.
Each specification of 41011 describes a lubricant supply composition consisting of polyethylene containing a lubricating oil. Japanese Patent Publication No. 23239/1988 discloses that the molecular weight is 1 ×.
There is described a lubricant supply composition in which lubricating grease is held in ultra high molecular weight polyethylene of about 10 ^{6 to} 5 × 10 ⁶ . These lubricant supply compositions gradually lubricate contained lubricants (lubricating oils and greases) and come in close proximity to lubricated members (inner and outer rings, rolling elements, cages).
To maintain lubrication over time.

[0004]

However, in the above-mentioned lubricant supply composition, both the polyethylene and the lubricant have low thermal conductivity, and particularly when the lubricant supply composition is filled into the internal space of the bearing without gaps. Thus, heat generated due to the rotation of the bearing is not released. In recent years, there has been a tendency for bearings to rotate at high speed, and the lubricant supply composition has become hotter, the resin component has softened, the mechanical strength has decreased, and the possibility of breakage has increased. In addition, the lubricant supply composition has a problem in that the higher the temperature, the greater the release amount of the contained lubricant, and thus the more quickly the composition is depleted.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, that is, to provide a lubricant supply composition capable of ensuring long-term lubrication and a rolling bearing filled with the lubricant supply composition.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention comprises a synthetic resin which is solidified in a state containing a lubricant and gradually oozes out the lubricant contained therein. A lubricant supply composition for supplying a lubricant to an adjacent member to be lubricated, the composition comprising a solid lubricant. In order to achieve the same object, the present invention provides an outer ring, an inner ring, a rolling bearing including a rolling element and a retainer, wherein the lubricant supply composition is provided in a space formed between the inner ring and the outer ring. A rolling bearing characterized by being filled is provided.

The inclusion of a solid lubricant increases the thermal conductivity of the lubricant supply composition as a whole and effectively radiates the heat generated with the rotation of the bearing to the outside of the bearing.
In particular, among solid lubricants, the thermal conductivity is 20 W / m ·
It has also been found that it is more effective to use ones above K. The present invention is based on such findings.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The lubricant supply composition of the present invention comprises a synthetic resin solidified in a state containing a lubricant and a solid lubricant. The lubricant, solid lubricant and synthetic resin are not particularly limited, but preferred examples will be described below.

[0009] The lubricant supply composition of the present invention comprises a synthetic resin selected from the group consisting of polyolefin resins having basically the same chemical structure, such as polyethylene, polypropylene, polybutylene, and polymethylpentene, and poly-α as a lubricant. -Any of paraffinic hydrocarbon oils such as olefin oils, naphthenic hydrocarbon oils, mineral oils, ether oils such as dialkyldiphenyl ether oils, ester oils such as phthalic acid esters, etc. The raw material obtained by mixing the solid lubricant with the prepared one is plasticized by heating it above the melting point of the resin and then plasticized, and then cooled to a solid state. It may be one to which various additives such as an agent, an antiwear agent, a defoamer, an extreme pressure agent and the like are added. As a solid lubricant, graphite (graphite) (thermal conductivity of 100 to 150 W / m
K), boron nitride (h-BN) (50 to 85 W / mK),
Known materials such as fluororesin (PTFE: 0.24 W / m · K), molybdenum disulfide (0.1 to 0.2 W / m · K), and tungsten disulfide (0.1 to 0.2 W / m · K) can be used. Graphite or boron nitride having a thermal conductivity of 20 W / m · K or more is preferable. These can be used in the form of fibers, whiskers, or the like, in addition to particles.

The composition ratio of the lubricant supply composition is 10 to 47% by weight of a polyolefin resin and 85% of a lubricant based on the total weight.
-50% by weight, solid lubricant 3-25% by weight. 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 is difficult to maintain the initial shape when a load is applied due to rotation of a bearing,
There is a high possibility that problems such as detachment from the internal space of the bearing may occur. On the other hand, when the polyolefin resin exceeds 47% by weight, the content of the lubricant is relatively small,
As a result, the supply of lubricant to the bearing is reduced, and the life of the bearing is shortened. When the amount of the solid lubricant is less than 3% by weight, the effect of increasing the thermal conductivity of the entire lubricant supply composition is small, and when it exceeds 25% by weight, the content of the lubricant is relatively small. As a result, 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 compound and a lubricant can provide a lubricant supply composition having a certain level of 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 retention of the lubricant supply composition 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 required to reach the limit amount of the lubricant that can be supplied from the lubricant supply composition is shortened, and the life of the bearing is shortened. However, the mechanical strength is improved. Therefore, considering the balance of moldability, mechanical strength, oil retention, and lubricant supply amount, the composition ratio of the lubricant supply composition is 0 to 5% by weight of those classified as wax and 8 of relatively low molecular weight. ~ 45% by weight, ultra high molecular weight 2 ~ 15% by weight,
It is practically preferable that the total amount of one resin is 10 to 47% by weight.

As an index of the mechanical strength, the hardness [HD _A (durometer hardness using scale A)] of the lubricant supply composition is preferably in the range of 65 to 85, more preferably in the range of 70 to 80. More preferably, there is. 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 supply composition, 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.

[0013] 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, inorganic fibers such as glass fibers and metal fibers, and those obtained by braiding these into a cloth, or aramid fibers. Organic fibers such as polyester fibers and the like and braided cloths 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 additive amount of the additives other than the above-mentioned polyolefin resin, lubricant and solid lubricant is 20% by weight or less of the total amount of the molding raw material as a whole, so that the lubricant supply capacity is maintained. It is preferable in doing.

As the synthetic resin which can be used in the present invention, in addition to those based on the polyolefin resin described above, any thermoplastic resin which can be injection-molded can be used. For example, polyester elastomers and the like can be increased. In addition to the thermoplastic resin, a 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.

The present invention also provides various rolling bearings filled with the above-mentioned lubricant supply composition. An example is shown below. For example, FIG. 1 is a cross-sectional view showing a ball bearing. The ball bearing is configured by holding a plurality of balls 4 as rolling elements between an inner ring 1 and an outer ring 2 via a retainer 3. In the present invention, the space formed by the inner ring 1, the outer ring 2, the cage 3 and the balls 4 is filled with the above-mentioned lubricant supply composition 5. In this ball bearing, the lubricant gradually oozing out of the lubricant supply composition 5 is supplied to the raceway surface of the inner ring 1, the raceway surface of the outer ring 2, the inner peripheral surface of the cage 3, and the surface of the ball 4 for a long time. Lubrication can be maintained, and the heat generated by rotation can be suppressed from accumulating in the lubricant supply composition 5 due to the heat transfer effect of the solid lubricant.

Further, a self-aligning roller bearing 10 filled with a lubricant supply composition as shown in FIG. 2 can be provided.
The self-aligning roller bearing 10 has a structure in which the rollers 14 as the rolling elements can be aligned, and accordingly, the entire bearing can be aligned. Specifically,
The self-aligning roller bearing 10 is provided between the inner ring 13 and the outer ring 12.
Barrel rollers 1 arranged in rows and staggered in the radial direction
4 is held by a retainer 15 integrally formed, and a guide wheel 16 for guiding rollers 14 between the retainer 15 and the inner ring 13 is arranged concentrically with the retainer 15. . Then, as shown in FIG.
, The gap between the outer end faces of the inner rings 13 and 14 and the gap between the inner end face of the rollers 14 and the guide wheel 16 are filled with the lubricant supply composition 17, respectively. I have. In the self-aligning roller bearing 10, the lubricant gradually oozing out of the lubricant supply composition 17 contains the raceway surface of the inner ring 13, the raceway surface of the outer ring 12, the surface of the cage 14, the surface of the rollers 14, and the guide wheels 16. Is supplied to the surface of the solid lubricant and long-term lubrication can be maintained, and the heat generated by rotation can be suppressed from accumulating in the lubricant supply composition 17 due to the heat transfer effect of the solid lubricant.

The method of filling the lubricant supply composition 17 is not particularly limited, but it is preferable to use the following injection molding method. In injection molding, as shown in FIGS. 4 and 5, a mold composed of two divided bodies 30 and 31 divided into two right and left parts is used. The two divided bodies 30 and 31 are formed with a concave portion 32 into which the outer ring 12 is fitted, a concave portion 33 into 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. The flange portion 34 has a surface along the outer end surface of the roller 14 and the collar 1 for preventing the inner ring 13 from falling off.
9 and a surface along a surface that is outside the orbit 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 bearings between the inner race 13 and the outer race 12 until the front end surface thereof comes into contact with the outer end surface of the roller 14, so that each surface of the flange 34 is Contact the corresponding surfaces of the bearing, the outer peripheral surface and the side surface of the outer ring 12 are fitted into the concave portion 32, and the inner peripheral surface and the side surface of the inner ring 13 are fitted into the concave portion 33. Further, a gate 35 is provided on the flange 34 of one of the divided bodies 30.
This gate 35 is a pin point gate,
Rollers 14 in the roller row along the outer peripheral line of the annular portion 5
And the same number as the number of rollers 14 in the roller row. When the divided body 30 is mounted on the bearing, the gate 35 is mounted on the roller row on which the divided body 30 is mounted (here, the roller row on the left side in the figure).
So as to be arranged at a position between adjacent rollers 14.

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. Accordingly, the molten lubricant supply composition 1 introduced into the mold sprue from the injection molding machine
After 7 enters the runner 36 and is spread out in a disk shape, it is introduced into the bearing from all the gates 35. Then, the molten lubricant supply composition 17 moves in the bearing as shown by the arrow in the figure. That is, the molten lubricant supply composition 17 first enters between the rollers 14 in the left row in the figure from the tip of the gate 35 as shown in FIG. It moves between the portion 15a and the outer ring 12 and reaches the space A between the annular portion of the retainer 15 and the outer ring 12. Further, a part moves between the outer end face of the holding part 15a of the retainer 15 and the flange part 34 of the mold, and part of the part moves with the outer end face of the inner surface part 14 of the fall prevention collar 19 of the inner race 13. Between the holding part 15a and the inner ring 13
3a to enter the space C between the guide wheels 16 and 14 and the inner end face. Next, as shown in FIG. 5, the molten lubricant supply composition 17 that has reached the space A enters between the rollers 14 in the right row in the figure, and the right holding portion 15b of the cage 15 and the outer ring. 12 and move. A part thereof moves between the outer end surface of the holding portion 15b and the flange portion 34 of the mold and enters a space D between the inner ring 13 and the collar 19 for preventing the inner ring 13 from falling off. Otherwise, the track 13a of the holding portion 15b and the inner ring 13
And enters a space E between the guide wheels 16 and 14 and the inner end surface thereof. Further, the molten lubricant supply composition 17 that has reached the space A also enters the space F between the inner end face of the roller 14 and the annular portion of the cage 15. 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.

Then, by removing the mold after performing the injection molding in this manner, as shown in FIG. 3, the inner space of the bearing, that is, each of the spaces A to F and the adjacent rollers 14 in each row are arranged. Thus, the self-aligning roller bearing 10 in which the lubricant supply composition 17 is filled and solidified is obtained. Prior to molding, it is preferable that the bearing is degreased and cleaned, and that a fluorine-based release agent described in Japanese Patent Application Laid-Open No. Hei 7-139551 by the present applicant is applied.

Further, an angular ball bearing 40 filled with a lubricant supply composition as shown in FIG. 6 can be provided.
That is, the angular ball bearing 40 is provided between the inner race 41 and the outer race 42 with the ball 43 having a predetermined contact angle and the crown-shaped cage 4.
4, the outside of the ball 43 is filled with a lubricant supply composition 45. Also, the lubricant supply composition 45
Is filled so as to form a gap C1 (for example, 0.5 mm) between the inner ring 41 and the inner ring 41. In this angular ball bearing 40, the lubricant gradually oozing out of the lubricant supply composition 45 is supplied to the raceway surface of the inner ring 41, the raceway surface of the outer ring 42, the surface of the cage 44 and the surface of the ball 43 for a long time. Lubrication can be maintained, and heat generated by rotation can be suppressed from accumulating in the lubricant supply composition 45 due to the heat transfer effect of the solid lubricant.

The above-mentioned angular ball bearing 40 is manufactured by 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 substantially the same as the length from the end surface (side surface) of the outer peripheral surface 41a of the inner race 41 to the end on the raceway groove 41b side. The gap C1 is adjusted by the thickness of the ring projection 51. The backing plate 50 is formed by integrally connecting a flat plate to a plate on which the ring forming ring projection 51 is protruded by a fixing screw 52. The molding is performed by filling the unsintered lubricant supply composition 45 with the jig B down, and performing heat molding.

[0024]

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

(Preparation of lubricant supply composition) High-density polyethylene (classified into relatively low molecular weight) 10% by weight, ultra-high molecular weight polyethylene (classified into ultra-high molecular weight) 12.5% by weight, and polyethylene wax (classified into wax) ) 2.5% by weight of a resin was mixed with 8% by weight of graphite powder and 67% by weight of mineral oil to prepare a lubricant supply composition A. Also, a lubricant supply composition B was prepared in the same manner except that the graphite powder of the lubricant supply composition A was changed to boron nitride (h-BN). Furthermore, 10% by weight of high density polyethylene (classified as relatively low molecular weight) and ultra high molecular weight polyethylene (classified as ultra high molecular weight)
A resin composed of 12.5% by weight and 2.5% by weight of polyethylene wax (classified as wax) and 75% by weight of mineral oil were mixed to prepare a lubricant supply composition C.

(Measurement of Thermal Conductivity) The above-mentioned lubricant supply compositions A, B and C were melted, filled in a predetermined mold, and then cooled to form a test piece. Then, the thermal conductivity of each test piece was measured at room temperature by a laser flash method. As a result of the measurement, the test piece of the lubricant supply composition A showed 0.35 W / m ·
K, and the test piece of the lubricant supply composition B was 0.33 W /
m · K, and the test piece of the lubricant supply composition C was 0.21
W / m · K. From this, the thermal conductivity is 20 W
It was confirmed that the thermal conductivity of the lubricant supply composition was significantly increased by containing a solid lubricant of / m · K or more.

(Bearing rotation test) In addition, spherical roller bearings
After degreasing and cleaning of 22331, a fluorine-based release agent described in JP-A-7-139551 was applied, and FIG.
Each of the lubricant supply compositions A, B, and C was injection-molded (insert-molded) in a state where the bearing was held in a mold as shown in FIG. The injection of the lubricant supply composition was performed from one side, and the gate was provided between each roller (pinpoint gate). The injection molding machine described in JP-A-8-309793 (improved hopper) was used. Then, a load of Fr = 500 kgf was applied to each of the test bearings, and the number of revolutions was increased from 300 rpm to 100 rpm in increments of 100 rpm, and the number of revolutions until the lubricant supply composition was damaged by melting or the like was examined. At that time, the rotation stops for 3 to 4 hours every time the rotation speed increases, and 20 to 24
Hold for hours. As a result, the test bearing filled with the lubricant supply composition A did not break down to 1200 rpm and the test bearing filled with the lubricant supply composition B did not break down to 1100 rpm, whereas the lubricant supply composition C did not break down to 1100 rpm. The filled test bearing failed at 900 rpm. Further, the bearing outer ring temperature was measured every time the rotation speed increased. The results are shown in FIG. 8. As shown, the higher the thermal conductivity of the solid lubricant, the smaller the gradient of the temperature rise, and accordingly, the higher the number of rotations before breakage. . From these results, it was confirmed that by containing the solid lubricant, the thermal conductivity of the lubricant supply composition was improved and the usable rotational speed was improved.

[0028]

As described above, the lubricant supply composition of the present invention has a high heat radiation effect, and a rolling bearing filled with the lubricant can suppress breakage due to heat generation due to the rotation of the bearing, and provide a good rotation for a long period of time. Is secured.

[Brief description of the drawings]

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

FIG. 2 shows another embodiment (a self-aligning roller bearing) of a rolling bearing filled with a lubricant supply composition according to the present invention.
FIG. 3 is a cross-sectional view of a main part showing a state before filling with a lubricant supply composition.

FIG. 3 is a cross-sectional view of a main part showing a state after a lubricant supply composition has been filled in the spherical roller bearing shown in FIG. 2;

FIG. 4 is a diagram for explaining a filling process of a lubricant supply composition by an injection molding method.

FIG. 5 is a diagram for explaining a filling process of a lubricant supply composition by an injection molding method.

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

FIG. 7 is a view for explaining a manufacturing process of the angular contact ball bearing shown in FIG. 6;

FIG. 8 is a graph showing the result of measuring the outer ring temperature for each bearing rotation speed in the bearing rotation test of the example.

[Description of Signs] 1 Inner ring 2 Outer ring 3 Cage 4 Ball 5 Lubricant supply composition 10 Self-aligning roller bearing 12 Outer ring 13 Inner ring 14 Roller 15 Cage 17 Lubricant supply composition 30, 31 Mold divided body 40 Angular Ball bearing 41 Inner ring 42 Outer ring 43 Ball 44 Cage 45 Lubricant supply composition

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 107/38 C10M 107/38 169/04 169/04 171/06 171/06 F16C 19/06 F16C 19 / 06 19/28 19/28 33/66 33/66 A // C10N 10:12 20:00 20:06 30:00 30:08 40:02 F term (reference) 3J101 AA02 AA13 AA32 AA42 AA43 AA52 AA62 BA80 CA01 CA12 EA53 FA32 4H104 AA04A AA19A AA26A CA01A CA01C CD02A DA02A EA04A EA07A EB02 FA06 LA04 LA20 PA01 QA11 QA21

Claims (3)

[Claims] 1. A lubricant supply composition comprising a synthetic resin solidified in a state containing a lubricant and gradually supplying a lubricant to an adjacent member to be lubricated by gradually oozing out the lubricant contained therein. , A lubricant supply composition comprising a solid lubricant. 2. The thermal conductivity of the solid lubricant is 20 W / m ·
The lubricant supply composition according to claim 1, wherein the composition has a K or more. 3. A rolling bearing comprising an outer ring, an inner ring, a rolling element and a cage, wherein a space formed between the inner ring and the outer ring is filled with the lubricant supply composition according to claim 1 or 2. A rolling bearing.