JP2007092790A

JP2007092790A - Sealed rolling bearing

Info

Publication number: JP2007092790A
Application number: JP2005280081A
Authority: JP
Inventors: Takashi Yagi; 隆司八木
Original assignee: NTN Corp; NTN Toyo Bearing Co Ltd
Current assignee: NTN Corp
Priority date: 2005-09-27
Filing date: 2005-09-27
Publication date: 2007-04-12

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed rolling bearing capable of securing durability and excellent sealing performance even if the inside of a bearing comes into negative pressure due to utilization under the environment where a large amount of water is scattered. <P>SOLUTION: Tensional pressure of a seal slide contact surface 1a by a seal lip 8c after reinforcement with a coil spring 10 of a contact seal 8 is set to be 0.3-0.6 MPa. The highly charged pressure of the seal slide contact surface 1a by the seal lip 8c before the reinforcement with the coil spring 10 is set to be 40-70% of the tensional pressure after the reinforcement with the coil spring 10. By so doing, frictional heat of the seal lip 8c which tenses the seal slide contact surface 1a is suppressed to secure durability. In addition, sufficient durability is applied to the seal lip 8c itself so as not to be deformed even if the inside of the bearing comes into negative pressure. As a result, excellent sealing performance can be secured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、接触シールのシールリップによる内輪側のシール摺接面の緊迫圧力を環状のばね部材で補強して、軸受内部を密封した密封型転がり軸受に関する。 The present invention relates to a hermetic rolling bearing in which an inner spring seal pressure reinforced by a seal lip of a contact seal is reinforced by an annular spring member to seal the inside of the bearing.

鉄鋼圧延機のロールネック部を支持する軸受のように、ロール冷却水や圧延潤滑油を分散させたエマルション等の水が多量に飛散する環境で使用され、軸受内外での温度差の発生により軸受内部が負圧になることがある転がり軸受には、接触シールの弾性部材で形成されたシールリップによる内輪側の摺接面の緊迫圧力を環状のばね部材で補強して、軸受内部を密封した密封型転がり軸受が多く用いられている（例えば、特許文献１参照）。 Used in an environment where a large amount of water, such as an emulsion in which roll cooling water or rolling lubricant is dispersed, is scattered, such as a bearing that supports the roll neck of a steel rolling mill. For rolling bearings that may have negative pressure inside, the pressure inside the sliding surface on the inner ring side by the seal lip formed by the elastic member of the contact seal is reinforced by an annular spring member to seal the inside of the bearing. Sealed rolling bearings are often used (see, for example, Patent Document 1).

特開２００４−５２９２４号公報JP 2004-52924 A

近年の鉄鋼圧延機の圧延速度の高速化に伴い、上述したシールリップの緊迫圧力を環状のばね部材で補強したばね付きの接触シールで軸受内部を密封した密封型転がり軸受では、シール摺接面を緊迫するシールリップの摩擦発熱が大きくなって、接触シールが早期に損傷する問題が生じている。 With the recent increase in rolling speed of steel rolling mills, in the case of sealed rolling bearings in which the inside of the bearing is sealed with a spring-loaded contact seal reinforced by the pressure of the sealing lip described above with an annular spring member, the seal sliding contact surface As a result, the frictional heat generated by the sealing lip that tightens the contact lip increases, causing a problem that the contact seal is damaged early.

この問題に対して、従来はシールリップの剛性を低くしてシールリップ自体の緊迫圧力を小さく設定しているが、シールリップ自体の緊迫圧力を小さく設定すると、軸受内部が負圧になったときに、シールリップが剛性の低下によって変形しやすくなり、シール性が極端に低下する問題がある。 To solve this problem, the rigidity of the seal lip itself has been lowered and the pressure applied to the seal lip itself has been set low. However, if the pressure on the seal lip itself is set to a low value, the inside of the bearing becomes negative. In addition, the seal lip is liable to be deformed due to a decrease in rigidity, and there is a problem that the sealing performance is extremely lowered.

そこで、本発明の課題は、水が多量に飛散する環境で使用され、軸受内部が負圧になっても、耐久性と良好なシール性を確保できる密封型転がり軸受を提供することである。 Accordingly, an object of the present invention is to provide a sealed type rolling bearing that is used in an environment in which a large amount of water scatters and can ensure durability and good sealing performance even when the inside of the bearing becomes negative pressure.

上記の課題を解決するために、本発明は、接触シールの弾性部材で形成されたシールリップで、内輪側に設けられたシール摺接面を緊迫し、このシールリップによる前記シール摺接面の緊迫圧力を環状のばね部材で補強して、軸受内部を密封した密封型転がり軸受において、前記ばね部材で補強した後のシールリップによる前記シール摺接面の緊迫圧力を０．３〜０．６ＭＰａとし、前記ばね部材で補強する前のシールリップによる前記シール摺接面の緊迫圧力を、前記ばね部材で補強した後の緊迫圧力の４０〜７０％とした構成を採用した。 In order to solve the above-described problems, the present invention provides a seal lip formed of an elastic member of a contact seal, pressing a seal slidable contact surface provided on the inner ring side, and forming the seal slidable contact surface by the seal lip. In a hermetic rolling bearing in which the pressure is reinforced with an annular spring member and the inside of the bearing is sealed, the pressure on the seal sliding contact surface by the seal lip after reinforcement with the spring member is 0.3 to 0.6 MPa. In addition, a configuration was adopted in which the pressing pressure of the seal sliding contact surface by the seal lip before being reinforced by the spring member was 40 to 70% of the pressing pressure after being reinforced by the spring member.

すなわち、ばね部材で補強した後のシールリップによるシール摺接面の緊迫圧力を０．３〜０．６ＭＰａとし、ばね部材で補強する前のシールリップによるシール摺接面の緊迫圧力を、ばね部材で補強した後の緊迫圧力の４０〜７０％とすることにより、シール摺接面を緊迫するシールリップの摩擦発熱を抑制して耐久性を確保するとともに、シールリップ自体に十分な剛性を持たせて、軸受内部が負圧になってもシールリップが変形しないようにし、良好なシール性を確保できるようにした。 That is, the tension pressure of the seal sliding contact surface by the seal lip after being reinforced by the spring member is 0.3 to 0.6 MPa, and the tension pressure of the seal sliding contact surface by the seal lip before being reinforced by the spring member is By setting the pressure to 40 to 70% of the pressure after reinforcement, the friction heat generated by the seal lip that presses the seal sliding contact surface is suppressed to ensure durability, and the seal lip itself has sufficient rigidity. Therefore, the seal lip is prevented from being deformed even when the bearing has a negative pressure so that a good sealing property can be secured.

本発明の密封型転がり軸受は、ばね部材で補強した後のシールリップによるシール摺接面の緊迫圧力を０．３〜０．６ＭＰａとし、ばね部材で補強する前のシールリップによるシール摺接面の緊迫圧力を、ばね部材で補強した後の緊迫圧力の４０〜７０％としたので、シール摺接面を緊迫するシールリップの摩擦発熱を抑制して耐久性を確保できるとともに、シールリップ自体に十分な剛性を持たせて、軸受内部が負圧になってもシールリップが変形しないようにし、良好なシール性を確保することができる。 The sealing type rolling bearing of the present invention is such that the pressure applied to the seal sliding contact surface by the seal lip after being reinforced by the spring member is 0.3 to 0.6 MPa, and the seal sliding contact surface by the seal lip before being reinforced by the spring member Since the tension pressure of the seal lip is 40 to 70% of the tension pressure after being reinforced with the spring member, it is possible to suppress the heat generated by friction of the seal lip that tightens the seal sliding contact surface and to ensure the durability. Sufficient rigidity is provided so that the seal lip is not deformed even when the bearing has a negative pressure, and good sealing performance can be ensured.

以下、図面に基づき、本発明の実施形態を説明する。この密封型転がり軸受は、図１に示すように、鉄鋼圧延機のロールネック部を支持する４列円錐ころ軸受であり、２列ずつの軌道面を有する左右２つの内輪１と、２列の軌道面を有する中央の外輪２ａおよびその両側に間座３を介して並べられた１列ずつの軌道面を有する２つの外輪２ｂとの間に、４列の円錐ころ４が保持器５で保持され、軸受内部が両端のサイドシール６と中央部の中間シール１１とで密封されている。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, this sealed rolling bearing is a four-row tapered roller bearing that supports a roll neck portion of a steel rolling mill, and includes two left and right inner rings 1 each having two raceways and two rows. Four rows of tapered rollers 4 are held by a cage 5 between a central outer ring 2a having a raceway surface and two outer rings 2b having one row of raceway surfaces arranged on both sides thereof via spacers 3. The inside of the bearing is sealed with side seals 6 at both ends and an intermediate seal 11 at the center.

前記サイドシール６は、図２に示すように、外輪２ｂの端面に当接された環状のシールケース７と、シールケース７の内周面に固定された接触シール８とから成り、シールケース７の外周面には、軸受箱（図示省略）との間をシールするＯリング９が装着されている。接触シール８は芯金８ａとニトリルブタジエンゴムの弾性部材８ｂとから成り、弾性部材８ｂで形成されたシールリップ８ｃが、内輪１の外端延長部の外周面に設けられたシール摺接面１ａを緊迫するように摺接し、シールリップ８ｃによるシール摺接面１ａの緊迫圧力が、シールリップ８ｃの外周側に嵌めこまれた環状のコイルばね１０で補強されている。 As shown in FIG. 2, the side seal 6 includes an annular seal case 7 that is in contact with the end surface of the outer ring 2 b and a contact seal 8 that is fixed to the inner peripheral surface of the seal case 7. An O-ring 9 that seals between the outer peripheral surface and a bearing box (not shown) is attached. The contact seal 8 includes a cored bar 8a and an elastic member 8b of nitrile butadiene rubber, and a seal lip 8c formed by the elastic member 8b is a seal sliding contact surface 1a provided on the outer peripheral surface of the outer end extension portion of the inner ring 1. The pressure of the seal sliding contact surface 1a by the seal lip 8c is reinforced by an annular coil spring 10 fitted on the outer peripheral side of the seal lip 8c.

前記中間シール１１は、図３に示すように、断面Ｌ字形の環状の芯金１１ａと弾性部材１１ｂとから成り、左右の内輪１の突き合わせ部の外周面に設けられた凹部１ｂに装着されて、弾性部材１１ｂで形成された２つのシールリップ１１ｃが、内輪１の突き合わせ部を跨ぐように凹部１ｂと接触するようになっている。なお、この中間シール１１は各内輪１と一緒に回転するので、各シールリップ１１ｃは凹部１ｂと摺接はしない。 As shown in FIG. 3, the intermediate seal 11 includes an annular cored bar 11a having an L-shaped cross section and an elastic member 11b, and is attached to a recess 1b provided on the outer peripheral surface of the butted portion of the left and right inner rings 1. The two seal lips 11c formed of the elastic member 11b come into contact with the recess 1b so as to straddle the butted portion of the inner ring 1. Since the intermediate seal 11 rotates together with each inner ring 1, each seal lip 11c does not make sliding contact with the recess 1b.

まず、前記コイルばね１０で補強された後のシールリップ８ｃによるシール摺接面１ａの緊迫圧力Ｐａを０．２〜０．７ＭＰａの範囲で変化させた４列円錐ころ軸受のサンプルを回転軸に取り付け、回転の進行に伴うシール状態の変化を調査する予備試験を行った。この予備試験では、軸受内部を外気圧と等しくし、シールリップ８ｃがシール摺接面１ａに摺接するリップ周速は８〜１５ｍ／秒の範囲で変化させた。 First, a sample of a four-row tapered roller bearing in which the pressing pressure Pa of the seal sliding contact surface 1a by the seal lip 8c after being reinforced by the coil spring 10 is changed in a range of 0.2 to 0.7 MPa is used as a rotating shaft. A preliminary test was conducted to investigate the change in the seal state with the progress of attachment and rotation. In this preliminary test, the inside of the bearing was made equal to the external air pressure, and the lip peripheral speed at which the seal lip 8c slidably contacts the seal slidable contact surface 1a was varied in the range of 8 to 15 m / sec.

表１に上記予備試験の結果を示す。この結果より、緊迫圧力Ｐａを０．３〜０．６ＭＰａの範囲としたサンプル３〜６は、いずれも良好なシール性が得られ、シール部での発熱も少なかった。一方、緊迫圧力Ｐａを０．２〜０．２５ＭＰａとしたサンプル１、２はシール性が不足し、緊迫圧力Ｐａを０．７ＭＰａとしたサンプル７はシール部で異常発熱が生じた。なお、表１には、前記コイルばね１０で補強される前のシールリップ８ｃによるシール摺接面１ａの緊迫圧力Ｐｂと補強された後の緊迫圧力Ｐａとの比Ｐｂ／Ｐａも併記した。 Table 1 shows the results of the preliminary test. From these results, all of Samples 3 to 6 in which the tension pressure Pa was in the range of 0.3 to 0.6 MPa provided good sealing properties, and the heat generation at the seal portion was small. On the other hand, Samples 1 and 2 in which the pressure pressure Pa was 0.2 to 0.25 MPa were insufficient in sealing performance, and Sample 7 in which the pressure pressure Pa was 0.7 MPa had abnormal heat generation at the seal portion. In Table 1, the ratio Pb / Pa between the pressure Pb of the seal sliding contact surface 1a by the seal lip 8c before being reinforced by the coil spring 10 and the pressure P Pa after being reinforced is also shown.

つぎに、前記予備試験で良好な結果が得られた緊迫圧力Ｐａを０．３〜０．６ＭＰａの範囲としたものについて、コイルばね１０による補強前後の緊迫圧力比Ｐｂ／Ｐａを変化させた４列円錐ころ軸受を回転軸に取り付け、軸受内部を外気圧に対して３０ｋＰａの負圧とした本試験を行った。なお、本試験でのリップ周速は１２ｍ／秒一定とした。 Next, the compression pressure ratio Pb / Pa before and after reinforcement by the coil spring 10 was changed for the compression pressure Pa in which a good result was obtained in the preliminary test in the range of 0.3 to 0.6 MPa. A row tapered roller bearing was attached to the rotating shaft, and this test was performed with the inside of the bearing at a negative pressure of 30 kPa with respect to the external pressure. Note that the lip peripheral speed in this test was constant at 12 m / sec.

表２に上記本試験の結果を示す。この結果より、緊迫圧力比Ｐｂ／Ｐａを４０〜７０％の範囲とした各実施例のものは、シール部での異常発熱も負圧によるシールリップの変形も生じることなく、良好なシール性が確保された。これに対して、緊迫圧力比Ｐｂ／Ｐａを２０〜３０％とした各比較例のものは、いずれも負圧によってシールリップが変形し、良好なシール性が得られなかった。 Table 2 shows the results of this test. From these results, the examples having the tension pressure ratio Pb / Pa in the range of 40 to 70% have good sealing performance without causing abnormal heat generation at the seal portion and deformation of the seal lip due to negative pressure. Secured. On the other hand, in each of the comparative examples in which the tension pressure ratio Pb / Pa was 20 to 30%, the seal lip was deformed by the negative pressure, and good sealability was not obtained.

上述した実施形態では、密封型転がり軸受を４列円錐ころ軸受としたが、本発明に係る密封型転がり軸受は、玉軸受やころ軸受等の他の種類の転がり軸受にも適用することができる。 In the embodiment described above, the sealed type rolling bearing is a four-row tapered roller bearing. However, the sealed type rolling bearing according to the present invention can also be applied to other types of rolling bearings such as a ball bearing and a roller bearing. .

密封型転がり軸受の実施形態を示す縦断面図Longitudinal sectional view showing an embodiment of a sealed rolling bearing 図１のサイドシールの部分を拡大して示す断面図Sectional drawing which expands and shows the part of the side seal of FIG. 図１の中間シールの部分を拡大して示す断面図Sectional drawing which expands and shows the part of the intermediate seal of FIG.

符号の説明Explanation of symbols

１内輪
１ａシール摺接面
１ｂ凹部
２ａ、２ｂ外輪
３間座
４円錐ころ
５保持器
６サイドシール
７シールケース
８接触シール
８ａ芯金
８ｂ弾性部材
８ｃシールリップ
９Ｏリング
１０コイルばね
１１中間シール
１１ａ芯金
１１ｂ弾性部材
１１ｃシールリップ DESCRIPTION OF SYMBOLS 1 Inner ring 1a Seal sliding contact surface 1b Recessed part 2a, 2b Outer ring 3 Spacer 4 Tapered roller 5 Cage 6 Side seal 7 Seal case 8 Contact seal 8a Core metal 8b Elastic member 8c Seal lip 9 O-ring 10 Coil spring 11 Intermediate seal 11a Core 11b Elastic member 11c Seal lip

Claims

接触シールの弾性部材で形成されたシールリップで、内輪側に設けられたシール摺接面を緊迫し、このシールリップによる前記シール摺接面の緊迫圧力を環状のばね部材で補強して、軸受内部を密封した密封型転がり軸受において、前記ばね部材で補強した後のシールリップによる前記シール摺接面の緊迫圧力を０．３〜０．６ＭＰａとし、前記ばね部材で補強する前のシールリップによる前記シール摺接面の緊迫圧力を、前記ばね部材で補強した後の緊迫圧力の４０〜７０％としたことを特徴とする密封型転がり軸受。 A seal lip formed of an elastic member of a contact seal is used to press the seal sliding contact surface provided on the inner ring side, and the pressure applied to the seal sliding contact surface by the seal lip is reinforced by an annular spring member. In a sealed-type rolling bearing with the inside sealed, the pressure applied to the seal sliding contact surface by the seal lip after being reinforced by the spring member is 0.3 to 0.6 MPa, and the seal lip before being reinforced by the spring member is used. A hermetic rolling bearing characterized in that the pressure applied to the seal sliding contact surface is 40 to 70% of the pressure applied after reinforcement by the spring member.