JP2012082882A - Roller bearing for running speed reducer for construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a more durable roller bearing for a running speed reducer for construction machinery.SOLUTION: The roller bearing 10 for a running speed reducer for construction machinery includes: an inner ring 11; an outer ring 12; a conical roller 13, which is a rolling element disposed between the inner ring 11 and the outer ring 12; and a retainer 14 composed of a resin composition containing a rubber material as an impact modifier in a resin, wherein the resin composition includes a polyamide, glass fibers and the rubber material having at least one functional group selected from carboxyl group, ester group and glycidyl group in molecules.

Description

  The present invention relates to a rolling bearing incorporated in a traveling speed reducer of a construction machine.

  As a traveling speed reducer used in a construction machine, for example, a configuration shown in FIG. 1 is known. A travel speed reducer 1 shown in the figure is connected to a housing 7 by a drive shaft 2 connected to a hydraulic motor (not shown), planetary gear mechanisms 3, 4, 5 that reduce the rotation of the drive shaft 2, and a rolling bearing 6. A rotating drum 8 that is rotatably supported and a sprocket 9 fixed to the rotating drum 8 are provided. Further, as the rolling bearing 6, an angular ball bearing or a combined back roller bearing is often used according to the weight of the machine body.

  On the other hand, since construction machines generally perform work in an undeveloped place, it is routinely raised and dropped on obstacles during traveling, and at that time, they receive a large drop impact (drop impact). Conventionally, a metal cage is used for the rolling bearing 6. However, since a large impact load is intermittently applied to the rolling bearing 6 as well, a metal cage having low impact resistance may be damaged. is there.

  In addition, metal cages generate wear powder due to friction when the bearing rotates, so that the wear life is reduced by mixing the wear powder into the lubricating oil, and the wear powder damages the rolling surface of the rolling element. Since there is a problem, a cage made of a fiber reinforced resin composition has also been proposed (see, for example, Patent Document 1).

JP 2006-226362 A

  However, there is a strong demand for improving the durability of a rolling bearing incorporated in a traveling speed reducer of a construction machine, and further improvement of impact resistance of the cage is indispensable.

  Accordingly, an object of the present invention is to provide a rolling bearing for a traveling speed reducer for a construction machine that has higher durability than before.

In order to achieve the above object, the present invention provides the following rolling bearing for a traveling speed reducer of a construction machine.
(1) A rolling bearing incorporated in a traveling speed reducer for a construction machine,
An inner ring, an outer ring, a rolling element disposed between the inner ring and the outer ring, and a cage made of a resin composition in which a rubber material as an impact resistance improver is blended with a resin. , Rolling bearings for travel reducers of construction machinery.
(2) The rolling bearing for a traveling speed reducer for a construction machine according to the above (1), wherein the resin composition contains polyamide 46, glass fiber, and a rubber material.
(3) The rolling bearing for a traveling speed reducer for a construction machine according to (1), wherein the resin composition contains polyamide 66, glass fiber, and a rubber material.
(4) The rubber material according to any one of the above (1) to (3), wherein the rubber material is a rubber having at least one functional group selected from a carboxyl group, an ester group and a glycidyl group in the molecule. Rolling bearings for travel reducers of construction machines as described.
(5) The rolling bearing for a traveling speed reducer for a construction machine according to any one of (1) to (4), wherein the rolling element is a tapered roller.

  In the rolling bearing for a traveling speed reducer of a construction machine according to the present invention, since the cage is made of a fiber reinforced resin composition, there is no problem due to wear powder like a metal cage, and the cage is an impact resistance improver. As a rubber material is included, the impact resistance is increased and the bearing durability is greatly improved.

It is a schematic sectional drawing which shows an example of the traveling speed reducer for construction machines. It is a schematic sectional drawing which shows a tapered roller bearing. It is a perspective view which shows the retainer for tapered rollers.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  A rolling bearing for a traveling speed reducer of a construction machine according to the present invention (hereinafter simply referred to as a “rolling bearing”) has been conventionally incorporated in a traveling speed reducer of a construction machine. Angular roller bearings can be mentioned. FIG. 2 is a cross-sectional view showing an example of the tapered roller bearing 10, which has a conical raceway surface 11a, a large collar portion 11b on the large diameter side of the raceway surface 11a, and a small collar portion 11c on the small diameter side. An inner ring 11, an outer ring 12 having a conical raceway surface 12a, a plurality of tapered rollers 13 disposed between the raceway surface 12a of the outer ring 12 and the raceway surface 11a of the inner ring 11, and these tapered rollers. And a cage 14 that guides and holds 13 at predetermined intervals in the circumferential direction. FIG. 3 is a perspective view showing the cage 14.

  In the present invention, a molded article of a resin composition containing a resin and reinforcing fibers and further containing a rubber material as an impact resistance improver is used as the cage 14.

  Since the resin can be injection-molded and is excellent in impact resistance, heat resistance and the like, a polyamide resin is preferable, and polyamide 46 or polyamide 66 is particularly preferable.

  In the resin composition, a rubber material is blended in order to improve impact resistance. There is no particular limitation on the type of rubber, but ethylene acrylate copolymer rubber, ethylene propylene non-conjugated diene rubber, maleic anhydride modified ethylene propylene non-conjugated diene rubber, butadiene rubber, styrene butadiene copolymer rubber, which are excellent in impact resistance improvement effect, Acrylic rubber, acrylonitrile butadiene rubber, silicon rubber, chloroprene rubber, hydrogenated nitrile rubber, carboxyl-modified hydrogenated nitrile rubber, epichlorohydrin rubber, and styrene, olefin, urethane, polyamide, polyvinyl chloride, and other thermoplastic elastomers Etc., and are blended singly or in combination. Among them, rubber having a functional group having a polarity such as carboxyl group, ester group, and glycidyl group in the molecule has a strong interaction with the polyamide resin and has a good affinity, so that the impact resistance can be greatly improved. In view of the ability, acrylic rubber, maleic anhydride-modified ethylene propylene non-conjugated diene rubber, and carboxyl-modified hydrogenated nitrile rubber are preferred. Moreover, even if it is rubber | gum which does not have these polar functional groups, it is preferable to use the thing modified | denatured so that it may have a polar functional group in a molecular chain.

  Further, since the rubber material is added and dispersed in the state of vulcanized powder rubber, the rubber material is preferably as fine as possible, and more preferably ultrafine powder having an average particle diameter of 200 nm or less.

  The content of the rubber material is preferably 2 to 15% by mass, more preferably 3 to 6% by mass, based on the total amount of the resin composition. When the content is less than 2% by mass, the effect of improving the impact resistance is poor and the practicality is low. On the other hand, if it exceeds 15% by mass, not only the impact resistance improving effect is saturated, but also the heat resistance may be adversely affected.

The resin composition is mixed with reinforcing fibers for reinforcement. 10-40 mass% of the resin composition whole quantity is preferable from a reinforcement surface, and, as for content of a reinforcing fiber, 20-30 mass% is more preferable.
If the content is less than 10% by mass, the reinforcing effect is not sufficient, and the rigidity of the cage does not increase. Moreover, when it exceeds 40 mass%, the fluidity | liquidity of a resin composition will fall and it will become difficult to carry out injection molding of a cage | basket with dimensional accuracy.

  As the reinforcing fiber, glass fiber is preferable, but a whisker-like reinforcing material such as carbon fiber, aramid fiber, or potassium titanate whisker may be used. Moreover, you may mix these. Further, the reinforcing fiber is preferably surfaced with a silane coupling agent or the like in order to enhance the adhesiveness with the polyamide resin.

  In addition to the above components, various additives may be blended in the resin composition as necessary. For example, it is preferable to add an iodide heat stabilizer and an amine heat stabilizer, either alone or as a mixture, in order to suppress deterioration due to heat generated by use.

  The present invention will be further described below with reference to examples, but the present invention is not limited thereto.

[Test 1]
(Examples 1-9, Comparative Example 1)
As Examples 1 to 9, 70% by mass of polyamide 46, 25% by mass of glass fiber, and 5% by mass of the rubber material shown in Table 1 were mixed, and a test piece for an Izod impact test defined by JIS K7110. Was made. Moreover, as Comparative Example 1, a test piece was prepared in which polyamide 46 was 75% by mass and glass fiber was 25% by mass. Each test piece was subjected to an Izod impact test defined by JIS K7110, and an Izod impact value was measured. The results are shown in Table 1 as relative values where the value of Comparative Example 1 is 1.

  As shown in Table 1, it can be seen that by adding a rubber material as an impact resistance improver, the impact resistance is improved by 20 to 40%. In particular, rubber materials having strong interaction with polyamide resin such as acrylic rubber (Example 2), carboxyl-modified hydrogenated nitrile rubber (Example 4), and maleic anhydride-modified ethylene propylene non-conjugated diene rubber (Example 6) are used. When blended, the impact resistance is greatly improved. Further tests were performed based on these results.

(Example 10)
For tapered roller bearings (inner diameter 300 mm, outer diameter 390 mm, width 42 mm) by injection molding a resin composition in which polyamide 46 is mixed by 70 mass%, glass fiber is 25 mass%, and hydrogenated nitrile rubber is mixed by 5 mass% A cage was prepared.

(Example 11)
A resin composition in which 70% by mass of polyamide 46, 25% by mass of glass fiber, and 5% by mass of carboxyl-modified hydrogenated nitrile rubber are mixed together is injection-molded to form a tapered roller bearing (inner diameter 300 mm, outer diameter 390 mm, width 42 mm). ) Was produced.

(Example 12)
Tapered roller bearing (inner diameter 300 mm, outer diameter 390 mm, width 42 mm) by injection molding a resin composition in which polyamide 46 is mixed by 70 mass%, glass fiber is 25 mass%, and ethylene propylene non-conjugated diene rubber is mixed by 5 mass% A cage was prepared.

(Example 13)
A resin composition in which 70% by mass of polyamide 46, 25% by mass of glass fiber, and 5% by mass of maleic anhydride-modified ethylene propylene nonconjugated diene rubber are mixed together is injection-molded to form a tapered roller bearing (inner diameter 300 mm, outer diameter 390 mm). , Width 42 mm) was produced.

(Comparative Example 2)
A rolled steel plate was pressed to produce a cage for tapered roller bearings (inner diameter 300 mm, outer diameter 390 mm, width 42 mm).

(Comparative Example 3)
A resin composition in which polyamide 46 was mixed at a ratio of 75 mass% and glass fiber was mixed at a ratio of 25 mass% was injection-molded to produce a cage for a tapered roller bearing (inner diameter 300 mm, outer diameter 390 mm, width 42 mm).

The cages of Examples 10 to 13 and Comparative Examples 2 to 3 were incorporated into tapered roller bearings, and a drop impact test was performed to evaluate the impact resistance of the cage. The drop impact test was performed at a vibration acceleration of 2940 m / s ² and a drop cycle of 120 cpm, and the number of drops in which the cage was damaged was determined. The results are shown in Table 2 as relative values where the number of drops in Comparative Example 2 is 1.

  As shown in Table 2, by using a resin cage in which a rubber material is blended as an impact resistance improver, the impact resistance is 13 to 15 times that when a metal cage is used. It turns out that it improves 1.3 to 1.5 times compared with the resin cage which is not mix | blended. In particular, when a rubber material having a strong interaction with a polyamide resin, such as carboxyl-modified hydrogenated nitrile rubber (Example 11) or maleic anhydride-modified ethylene propylene non-conjugated diene rubber (Example 13), is blended. Great improvement effect.

[Test 2]
(Examples 14 to 22, Comparative Example 4)
As Examples 14-22, 70% by mass of polyamide 66, 25% by mass of glass fiber, and 5% by mass of the rubber material shown in Table 3 were mixed, and a specimen for an Izod impact test defined by JIS K7110. Was made. Moreover, as Comparative Example 4, a test piece was prepared in which polyamide 66 was 75% by mass and glass fiber was 25% by mass. Each test piece was subjected to an Izod impact test defined by JIS K7110, and an Izod impact value was measured. The results are shown in Table 3 as relative values where the value of Comparative Example 4 is 1.

  As shown in Table 3, it is understood that the impact resistance is improved by 20 to 40% by blending a rubber material as an impact resistance improver. In particular, rubber materials having strong interaction with the polyamide resin such as acrylic rubber (Example 15), carboxyl-modified hydrogenated nitrile rubber (Example 17), and maleic anhydride-modified ethylene propylene non-conjugated diene rubber (Example 19) are used. When blended, the impact resistance is greatly improved. Further tests were performed based on these results.

(Example 23)
A resin composition in which 70% by mass of polyamide 66, 25% by mass of glass fiber, and 5% by mass of carboxyl-modified hydrogenated nitrile rubber are mixed together is injection-molded to form a tapered roller bearing (inner diameter 180 mm, outer diameter 240 mm, width 25 mm). ) Was produced.

(Example 24)
70% by mass of polyamide 66, 25% by mass of glass fiber, and a resin composition in which maleic anhydride-modified ethylene propylene non-conjugated diene rubber is mixed at a rate of 5% by mass is injection-molded and tapered roller bearings (inner diameter 180 mm, outer diameter 240 mm). , Width 25 mm).

(Comparative Example 5)
A rolled steel plate was pressed to produce a cage for a tapered roller bearing (inner diameter 180 mm, outer diameter 240 mm, width 25 mm).

(Comparative Example 6)
A resin composition in which polyamide 66 was mixed at a ratio of 75 mass% and glass fiber at a ratio of 25 mass% was injection-molded to produce a cage for tapered roller bearings (inner diameter 180 mm, outer diameter 240 mm, width 25 mm).

The cages of Examples 23 to 24 and Comparative Examples 5 to 6 were incorporated into tapered roller bearings, and a drop impact test was performed to evaluate the impact resistance of the cage. The drop impact test was performed at a vibration acceleration of 2940 m / s ² and a drop cycle of 120 cpm, and the number of drops in which the cage was damaged was determined. The results are shown in Table 4 as relative values where the number of drops in Comparative Example 5 is 1.

  As shown in Table 4, by using a resin cage containing a rubber material as an impact resistance improver, the impact resistance is 13 to 14 times that when a metal cage is used. It turns out that it improves 1.3 to 1.4 times compared with the resin cage which is not mix | blended.

DESCRIPTION OF SYMBOLS 1 Traveling reducer 2 Drive shaft 3, 4, 5 Planetary gear mechanism 3a, 4a, 5a Sun gear 3b, 4b, 5b Internal gear 3c, 4c, 5c, 6 Rolling bearing 3d, 4d, 5d Planetary carrier 3e, 4e, 5e planetary gear 7 housing 8 rotating drum 9 sprocket 10 tapered roller bearing 11 inner ring 12 outer ring 13 tapered roller 14 cage

Claims (5)

A rolling bearing incorporated in a traveling speed reducer for a construction machine,
An inner ring, an outer ring, a rolling element disposed between the inner ring and the outer ring, and a cage made of a resin composition in which a rubber material as an impact resistance improver is blended with a resin. , Rolling bearings for travel reducers of construction machinery.   The rolling bearing for a traveling speed reducer for a construction machine according to claim 1, wherein the resin composition contains polyamide 46, glass fibers, and a rubber material.   The rolling bearing for a traveling speed reducer for a construction machine according to claim 1, wherein the resin composition contains polyamide 66, glass fiber, and a rubber material.   The running of a construction machine according to any one of claims 1 to 3, wherein the rubber material is a rubber having in a molecule thereof at least one functional group selected from a carboxyl group, an ester group and a glycidyl group. Rolling bearing for reducer.   The rolling bearing for a traveling speed reducer for a construction machine according to any one of claims 1 to 4, wherein the rolling element is a tapered roller.

Images