JP2010112500A - Seal for rolling support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal for a rolling support device constituting a rotating support part of a device used for a long time in a high temperature, high speed rotation and high load environment, capable of maintaining suitable sealing performance regardless of combination with sealed grease. <P>SOLUTION: A rubber molding 3 of the seal 1 is obtained by vulcanizing and molding a rubber composition wherein raw material rubber is silicone rubber, a cross-linking agent is organic peroxide, and a cross-linking auxiliary agent is tris (2-acryloyloxyethyl) isocyanurate. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a seal suitable for a rolling support device such as a rolling bearing, a linear guide device, and a ball screw.

Conventionally, rolling bearings have been designed to prevent grease existing in the rolling element installation part and dust generated during use from leaking to the outside, and dust floating outside from entering the rolling element installation part. A seal may be attached between the outer ring and the inner ring. An example of a rolling bearing with such a seal is shown in FIG.
The rolling bearing in this figure is a double-seal bearing with seals on both sides, and the seal 1 is formed by integrally vulcanizing and molding a ring-shaped cored bar 2 having a flange on the outer periphery and a synthetic rubber on the outside thereof. It is comprised with the rubber molding 3 which becomes. In view of its function, this seal is composed of an annular main portion 11 made of an elastic body other than the flange portion of the core metal and an outer elastic body thereof, and an inner surface of the outer ring 4 made up of the flange portion of the core metal and an elastic body outside the core portion. It is divided into a crimping portion 12 that is locked in the stop groove 41 and a lip portion 13 that is made of an elastic body on the inner peripheral side of the core metal and that is slidably contacted (slidably contacted) with the receiving groove 51 on the outer peripheral surface of the inner ring 5.

The seal 1 is inserted into the retaining groove 41 on the inner peripheral surface of the outer ring while elastically deforming the crimping portion 12 with the lip portion 13 in contact with the receiving groove 51 on the outer peripheral surface of the inner ring. Arranged between the outer ring 4 and the inner ring 5.
As a general material of such a seal, a steel plate such as SPCC or SECC is used as a core metal, and a synthetic rubber such as nitrile rubber, acrylic rubber, or fluorine rubber is used as a rubber molded body that forms a lip or the like. . In particular, in applications where chemical resistance and heat resistance are required, general fluororubbers such as vinylidene fluoride-hexafluoropropylene fluororubber and vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene fluororubber are used. Sometimes used.

  In recent years, higher speed and higher efficiency of the spindle speed of equipment have progressed, and a rolling support device having high reliability at high temperatures is required. For this purpose, sealing performance is important, and seals made of nitrile rubber, acrylic rubber, or the above-mentioned general fluoro rubber cannot always ensure high reliability and durability depending on the combination with the grease to be enclosed. there is a possibility.

On the other hand, in the following Patent Document 1, in a rolling bearing constituting a rotation support portion for an automobile engine auxiliary machine such as an alternator and a compressor, when the grease to be sealed is urea grease, rubber molding of a seal is performed. It is described that the body comprises a crosslinkable fluororubber composition containing vinylidene fluoride-tetrafluoroethylene-propylene terpolymer or tetrafluoroethylene-propylene binary copolymer.
JP 2001-65578 A

  An object of the present invention is to provide a seal for a rolling support device that constitutes a rotation support portion of a device that is used for a long period of time in a high temperature, high speed rotation, high load environment, such as an alternator or a compressor, The object is to provide a material that can maintain good sealing performance regardless of the combination.

  In order to solve the above-described problems, the present invention provides a first member and a second member having raceway surfaces arranged opposite to each other, and a plurality of rolling elements disposed between the raceway surfaces of both members. A rolling support device in which one of the first member and the second member moves relative to the other when the rolling member rolls, and is attached between the first member and the second member. A rubber molded body that is a seal and includes a lip portion that is in sliding contact with the first member or the second member, the raw rubber is silicone rubber, the cross-linking agent is an organic peroxide, and the cross-linking aid is Tris ( There is provided a seal for a rolling support device, which is obtained by vulcanization molding of a rubber composition which is 2-acryloyloxyethyl) isocyanurate.

  According to the seal of the present invention, by using tris (2-acryloyloxyethyl) isocyanurate as a crosslinking aid for silicone rubber, compared to the case of using a general crosslinking aid such as triallyl isocyanurate, Since the crosslink density of the obtained rubber molded body is increased, the breaking strength of the rubber molded body is increased. Moreover, since it is made of silicone rubber, it is excellent in chemical resistance and heat resistance. Therefore, good sealing performance can be maintained as a seal for the rolling support device constituting the rotation support portion of the device used for a long period of time under high temperature, high speed rotation and high load environment regardless of the combination with the grease to be enclosed.

The composition of the rubber composition used in the present invention is 0.5 to 2.0 parts by weight of an organic peroxide with respect to 100 parts by weight of the silicone rubber from the balance between the tensile strength and the hardness of the rubber molded body to be obtained. The tris (2-acryloyloxyethyl) isocyanurate is preferably 1.0 to 5.0 parts by weight.
When the amount of the organic peroxide is less than 0.5 parts by weight, the effect of increasing the crosslinking density is not substantially obtained. When the compounding amount of the organic peroxide exceeds 2.0 parts by weight, the amount of crosslinking becomes excessive, and the viscoelasticity necessary for sealing properties cannot be obtained. If the amount of tris (2-acryloyloxyethyl) isocyanurate is less than 1.0 part by weight, the effect of increasing the tensile strength cannot be substantially obtained. When the blending amount of tris (2-acryloyloxyethyl) isocyanurate exceeds 5.0 parts by weight, it cannot be compatible with the silicone rubber, and kneading becomes difficult.

Examples of the silicone rubber constituting the rubber composition used in the present invention include polydimethyl silicone rubber, methyl vinyl silicone rubber, and methyl phenyl silicone rubber.
Examples of the organic peroxide (crosslinking agent) constituting the rubber composition used in the present invention include dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, para Methylbenzoyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,3-bis (t-butylperoxyisopropyl) benzene, 2,5-di (t-butyl) Peroxy) hexane and the like.

  The rubber composition used in the present invention preferably further contains a silica component as a filler. Examples of the silica component include fumed silica, wet silica, fumed silica, and wet silica whose surface has been subjected to a hydrophobic treatment, quartz fine powder, diatomaceous earth, and the like. These silica components may contain other fillers such as calcium silicate, calcium carbonate, carbon black, glass fibers and the like.

The blending amount of the filler in the rubber composition used in the present invention is 10 to 300 parts by weight with respect to 100 parts by weight of the silicone rubber. When the blending amount of the filler is less than 10 parts by weight, the reinforcing action due to the addition of the filler is not substantially obtained, and the processability becomes insufficient. When the blending amount of the filler exceeds 300 parts by weight, processability such as mold flowability and dischargeability during molding is extremely lowered.
The rubber composition used in the present invention may further contain a known additive. Additives include dispersants such as low molecular weight siloxanes with a polymerization degree of 100 or less, silanol group-containing silanes, alkoxy group-containing silanes, heat resistance improvers such as iron oxide, cesium oxide, iron octylate, titanium oxide, various pigments, etc. A flame retardant aid such as a colorant, a platinum compound, and a palladium compound can be appropriately blended.

The rubber composition used in the present invention can be obtained by putting each component into a rubber kneading apparatus such as a rubber kneading roll, a pressure kneader, or a Banbury mixer and uniformly kneading. The kneading conditions are normal conditions, for example, kneading at a temperature of 30 to 80 ° C. and a treatment time of 5 to 60 minutes, so that components other than the silicone rubber can be uniformly dispersed in the silicone rubber.
The rubber molded body of the seal of the present invention is obtained by vulcanization molding of such a rubber composition. As the vulcanization molding method, the rubber composition after kneading may be placed in a mold and heated while being pressurized, and usual rubber molding methods such as compression molding, transfer molding, and injection molding can be employed. As vulcanization conditions, secondary vulcanization is usually performed under pressure at a temperature of 120 to 200 ° C. for about 30 seconds to 30 minutes, and further maintained at a temperature of 120 to 200 ° C. for about 10 minutes to 10 hours. I do.

  The physical properties necessary for the rubber molding of the seal for the rolling support device are as follows: hardness is 60 to 80 (preferably 65 to 75) in durometer hardness A scale (JIS K6301), and tensile strength (JIS K6251) is 10 to 25 MPa (preferably Is 25 to 25 MPa) and the elongation (JIS K6251) is 200 to 400% (preferably 250 to 400%). Therefore, the composition of the rubber composition and the vulcanization conditions are set so as to fall within this range.

  According to the seal of the present invention, as a seal for a rolling support device that constitutes a rotation support portion of a device that is used for a long time under a high temperature, high speed rotation, and high load environment, it is excellent regardless of the combination with the grease to be enclosed. The sealing performance can be sustained.

Hereinafter, embodiments of the present invention will be described.
As a silicone rubber, a silicone rubber compound “KE-971-U” of Shin-Etsu Chemical Co., Ltd. was prepared. This is a mixture of about 45 parts by weight of silica with 100 parts by weight of methyl vinyl silicone rubber.
As a cross-linking agent, “C-8” of Shin-Etsu Chemical Co., Ltd. was prepared. This is a crosslinking agent comprising an organic peroxide, and the main component is 2,5-dimethyl-2,5-bis (tertiary butyl peroxy) hexane.

As a crosslinking aid, “FA731A” of Hitachi Chemical Co., Ltd. and “TAIC” of Nippon Kasei Co., Ltd. were prepared. “FA731A” is tris (2-acryloyloxyethyl) isocyanurate and “TAIC” is triallyl isocyanurate.
In sample No. 1, a rubber kneading roll was used to mix a rubber composition containing 1.0 part by weight of a crosslinking agent and 1.0 part by weight of a crosslinking aid “FA731A” with respect to 100 parts by weight of a silicone rubber compound. Kneaded and formed into a sheet.

In sample No. 2, a rubber kneading roll was used to mix a rubber composition containing 1.0 part by weight of a crosslinking agent and 1.5 parts by weight of a crosslinking aid “FA731A” with respect to 100 parts by weight of a silicone rubber compound. Kneaded and formed into a sheet.
In Sample No. 3, a crosslinking agent was blended at a ratio of 2.0 parts by weight with respect to 100 parts by weight of the silicone rubber compound, and a rubber composition not blended with a crosslinking aid was kneaded with a rubber kneading roll to form a sheet. Molded.

In sample No. 4, a rubber composition kneading roll was used to mix a rubber composition containing 1.0 part by weight of a crosslinking agent and 1.0 part by weight of a crosslinking aid “TAIC” with respect to 100 parts by weight of a silicone rubber compound. Kneaded and formed into a sheet.
The secondary vulcanization which hold | maintains at 200 degreeC for 4 hours, after performing temporary vulcanization by heat-pressing each sheet-like molding (No. 1-4) of No. 1-4 for 5 to 10 minutes at 170 degreeC As a result, a sheet-like vulcanized molded product (crosslinked product) having a thickness of 2 mm was obtained.

  Three or more of the obtained sheet-like vulcanized molded articles Nos. 1 to 4 were stacked (with a thickness of 6 mm or more) and applied to a type A durometer, and the durometer hardness A was measured according to JIS K6301. Further, according to JIS K6251, a tensile test was performed under conditions of a temperature of 23 ° C. and a tensile speed of 500 mm / min, and the strength and elongation at break were measured. These results are shown in Table 1 below.

The No. 1 and 2 sheet-like vulcanized moldings corresponding to the rubber molded body of the seal of the present invention have the physical properties necessary for the rubber molded body of the seal for rolling support devices in all of hardness, tensile strength and elongation. ing.
On the other hand, the No. 3 sheet-like vulcanized molded product which does not correspond to the rubber molded body of the seal of the present invention satisfies the tensile strength of 10 to 25 MPa required for the rubber molded body of the seal for a rolling support device. Absent. The No. 4 sheet-like vulcanized product which does not correspond to the rubber molded body of the seal of the present invention has a tensile strength and elongation of 10 to 25 MPa and 200 to 400% necessary for the rubber molded body of the rolling support device seal. not filled.

When the seal 1 of the rolling bearing shown in FIG. 1 is manufactured, the kneaded material obtained by kneading the rubber composition No. 1 or 2 with a rubber kneading roll is put together with the core metal 2 into a mold and vulcanized. Thus, the rubber molded body 3 is integrally molded with the cored bar 2.
The automobile hub unit 6 shown in FIG. 2 has a seal 10 attached to the outer periphery, and the seal 10 is also composed of a core metal 20 and a rubber molded body 30. The hub unit 6 is a unit in which a hub 61 into which a shaft is inserted and a flange 62 are integrally formed. The seal 10 has two lip portions 31 and 32 slidably contacted with the hub 61 and one lip portion 33 slidably contacted with the flange 62. As the rubber composition for the rubber molded body 30, No. 1 or 2 rubber composition is used.

  In the water pump used for the water-cooled engine of the automobile shown in FIG. 3, a plurality of bearings J (FIG. 3) in which the central portion of the rotating shaft S having the impeller 71 fixed to one end are arranged at intervals in the axial direction. In this case, the outer peripheral surface of the integrally formed outer ring is displayed instead of the cross section of the plurality of bearing portions. A cooling water container 73 into which the cooling water W is put is fixed to the casing 72. A seal 100 closes between the bearing J and the impeller 71. As the rubber composition for the rubber molded body of the seal 100, the rubber composition No. 1 or 2 is used.

  FIG. 4 shows a linear guide device. As shown in FIG. 4A, the linear guide device includes a guide rail 510 and a slider 520, and seals 110 are attached to both ends of the slider 520 in the sliding direction. As shown in FIG. 4B, the seal 110 includes a metal cored bar 210 and a rubber molded body 310 and has three lip portions 311 to 313. As the rubber composition for the rubber molded body 310 of the seal 110, No. 1 or 2 rubber composition is used.

  FIG. 5 shows a ball screw. As shown in FIG. 5A, the ball screw includes a screw shaft 610 and a nut 620, and seals 120 are attached to both ends of the nut 620 in the axial direction. As shown in FIG. 5B, the seal 120 includes a metal cored bar 220 and a rubber molded body 320, and has a lip portion 321 that contacts the thread groove 611 of the screw shaft 610. As the rubber composition for the rubber molded body 320 of the seal 120, No. 1 or 2 rubber composition is used.

It is sectional drawing which shows an example of the rolling bearing with a seal | sticker. It is sectional drawing which shows an example of the hub unit with the seal. It is sectional drawing which shows an example of a water pump. It is the perspective view (a) which shows a linear guide apparatus, and sectional drawing (b) which shows the seal | sticker of a linear guide apparatus. It is the front view (a) which shows a ball screw, and sectional drawing (b) which shows the seal | sticker of a ball screw.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seal 11 Main part 12 Clamping part 13 Lip part 2 Metal core 3 Rubber molding 4 Outer ring 40 Outer ring 41 Stop groove 5 Inner ring 51 Receiving groove 6 Hub unit 61 Hub 62 Flange 7 Water pump 71 Impeller 72 Casing 73 Cooling water container 100 Seal 110 Seal 120 Seal 210 Core metal 220 Core metal 310 Rubber molded body 311 Lip portion 312 Lip portion 313 Lip portion 320 Rubber molded body 321 Lip portion 510 Guide rail 520 Slider 610 Screw shaft 611 Screw groove 620 Nut J Bearing S Rotating shaft W Cooling water

Claims (1)

At least a first member and a second member having raceway surfaces arranged opposite to each other, and a plurality of rolling elements arranged so as to be freely rollable between the raceway surfaces of both members, the rolling element rolling A rolling support device in which one of the first member and the second member moves relative to the other by doing so is a seal attached between the first member and the second member,
In the rubber molded body including the lip portion that is brought into sliding contact with the first member or the second member, the raw rubber is silicone rubber, the crosslinking agent is an organic peroxide, and the crosslinking aid is tris (2-acryloyloxyethyl). ) A seal for a rolling support device, which is obtained by vulcanization molding of a rubber composition which is isocyanurate.

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