JP2006214549A - Sealed rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sealed rolling bearing securing sufficient sealing performance even if the same is used under a condition where mud water splashes. <P>SOLUTION: A bearing space between an inner ring 1 and an outer ring 2 is sealed by an inner and an outer two contact seals 5, 6 and lip interference of the outer contact seal 6 is established to 0.4 mm or more. Mud water can be completely shut off by the outer contact seal 6 and mud water is prevented from adhering on the lip 5c and a seal slide surface 1a of the inner contact seal 5 even if a lip 6c and a seal slide surface 2a of the outer contact seal 6 are worn by splashing mud water. Consequently, sufficient sealing performance can be secured even if the bearing is used under a condition where mud water splashes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hermetic rolling bearing in which a bearing space between an inner ring and an outer ring is sealed with a contact seal.

  Rolling bearings used in an environment where dust, water, etc. are scattered have a sealed type rolling bearing in which the bearing space is sealed with a contact seal in order to prevent them from entering the bearing space between the inner ring and the outer ring. It is used. The contact seal seals the bearing space by bringing a lip formed of an elastic member such as rubber into contact with a seal sliding contact surface of an inner ring or an outer ring.

  This type of sealed-type rolling bearing is provided with one contact seal on each side of the bearing space (see, for example, Patent Document 1), or on the outside of the contact seals installed one by one. Some have a contact shield (see, for example, Patent Documents 2 and 3). In what is described in Patent Document 2, a shield (shielding plate) is divided into one attached to an inner ring and one attached to an outer ring, and a labyrinth gap is formed between these divided shields. Moreover, in what was described in patent document 3, the labyrinth clearance gap was formed between the shield (cover) and the inner contact seal. Furthermore, Patent Document 2 and Patent Document 3 also describe a configuration in which a lip provided on a contact seal is in contact with a shield.

  On the other hand, rolling bearings used for a center shaft support portion of a propeller shaft of an automobile, a joint shaft support portion of a drive shaft, and the like are disposed in an under-floor portion of the vehicle and thus receive muddy water scattering.

Japanese Utility Model Publication No. 7-10555 (Fig. 1) Japanese Utility Model Publication No. 8-3710 (Figs. 1 and 2) JP 2001-50288 A (Figs. 1, 3 to 10)

  When a sealed rolling bearing such as that described in Patent Document 1 is used at the site that receives the scattering of muddy water as described above, the scattered muddy water adheres to the lip of the contact seal and the seal sliding contact surface, and mud in the muddy water. Therefore, there is a problem that the lip and the seal sliding contact surface are worn and the sealing performance is remarkably lowered.

  The sealed rolling bearings described in Patent Document 2 and Patent Document 3 can prevent muddy water from directly adhering to the lip or seal sliding surface of the contact seal by the shield, but the shield has a non-contact gap. The muddy water penetrates from the gap through the labyrinth gap between the shield and the contact seal. The muddy water that has entered between the shield and the contact seal in this way increases in the concentration of the mud due to the evaporation of moisture, so if the muddy water with increased concentration of the mud adheres to the lip or seal sliding surface of the contact seal , These wear is promoted. For this reason, it is not possible to sufficiently prevent a decrease in sealing performance.

  Accordingly, an object of the present invention is to provide a hermetic rolling bearing that can sufficiently ensure sealing performance even when used in an environment where muddy water scatters.

  In order to solve the above problems, the present invention provides a sealed rolling bearing in which a bearing space between an inner ring and an outer ring is sealed with a contact seal that brings a lip formed of an elastic member into contact with a seal sliding contact surface. The space was sealed with the inner and outer two contact seals, and the lip tightening margin of the outer contact seal was set to 0.4 mm or more.

  That is, the bearing space is sealed with two inner and outer contact seals, and the lip tightening allowance of the outer contact seal is set to 0.4 mm or more, so that the lip and seal sliding surface of the outer contact seal is caused by the scattered muddy water. Even if it is worn, the outer contact seal can completely block muddy water, and the inner contact seal lip and seal sliding surface should not adhere to the muddy water. A sufficient sealing performance was secured.

  The lip tightening allowance of the outer contact seal is set to 0.4 mm or more because the wear amount of the contact seal lip and the seal sliding contact surface in the durability test of the sealed rolling bearing in an environment where muddy water is scattered. This is because the wear amount of the lip after the test time assuming the life of the automobile was 0.3 mm or less, and the wear amount of the seal sliding contact surface was 0.1 mm or less.

  For the elastic member forming the lip of the outer contact seal, nitrile rubber or fluororubber having excellent wear resistance is suitable.

  By bringing the lip of the outer contact seal into surface contact with the seal sliding contact surface, muddy water can be more completely blocked by the outer contact seal.

  The sealed rolling bearing of the present invention seals the bearing space with two inner and outer contact seals and sets the lip tightening margin of the outer contact seal to 0.4 mm or more, so that the outer contact seal is scattered by the scattered muddy water. Even if the lip or seal sliding contact surface wears out, muddy water is completely blocked by the outer contact seal, and muddy water is prevented from adhering to the lip and seal sliding contact surface of the inner contact seal. Even if it is used in an environment, it is possible to ensure sufficient sealing performance.

  By bringing the lip of the outer contact seal into surface contact with the seal sliding contact surface, muddy water can be more completely blocked by the outer contact seal.

  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 ball bearing in which a bearing space in which a ball 3 is held by a cage 4 between an inner ring 1 and an outer ring 2 is sealed with two inner and outer contact seals 5 and 6. It is.

  As shown in FIG. 2, each of the contact seals 5 and 6 includes cored bar portions 5a and 6a, and elastic portions 5b and 6b formed of an elastic member, respectively. The inner contact seal 5 is attached to a groove 2 b provided on the inner diameter surface of the outer ring 2 by an elastic portion 5 b, and its lip 5 c is in contact with the seal sliding contact surface 1 a of the inner ring 1. Further, the outer contact seal 6 is attached by fitting a cored bar portion 6 a to a stepped portion 1 b provided on the outer diameter surface of the inner ring 1, and its lip 6 c contacts the seal sliding contact surface 2 a of the outer ring 2. ing. In order to prevent muddy water from entering from the fitting portion of the cored bar 6a, the contact seal 6 is also provided with a lip 6d for sealing the outside of the fitting portion.

  The elastic portion 6b of the outer contact seal 6 is formed of nitrile rubber or fluororubber, and the lip 6c is in surface contact with the seal sliding contact surface 2a on the side surface, and the lip 6c and the seal sliding contact surface 2a are in contact with each other. The lip tightening allowance is set to 0.4 mm or more so that no gap is generated between them even if wear occurs. Therefore, the muddy water scattered around is completely blocked by the outer contact seal 6 and does not reach the inner contact seal 5.

  In the embodiment described above, the sealed type rolling bearing is a ball bearing, but the sealed type rolling bearing according to the present invention can also be used for other types of rolling bearings such as a roller bearing. Moreover, the form of the inner and outer contact seals is not limited to that of the embodiment, and any outer contact seal may be used as long as it contacts the seal sliding contact surface with a lip tightening margin set to 0.4 mm or more. .

Longitudinal sectional view showing an embodiment of a sealed rolling bearing Sectional drawing which expands and shows the principal part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 1a Seal sliding contact surface 1b Step part 2 Outer ring 2a Seal sliding contact surface 2b Groove 3 Ball 4 Cage 5, 6 Contact seal 5a, 6a Core metal part 5b, 6b Elastic part 5c, 6c, 6d Lip

Claims (3)

  In a sealed type rolling bearing in which a bearing space between an inner ring and an outer ring is sealed with a contact seal in which a lip formed of an elastic member is brought into contact with a seal sliding contact surface, the bearing space is sealed with two inner and outer contact seals, A sealed type rolling bearing characterized in that a lip tightening margin of an outer contact seal is set to 0.4 mm or more.   The sealed rolling bearing according to claim 1, wherein the elastic member forming the lip of the outer contact seal is nitrile rubber or fluororubber.   3. The sealed rolling bearing according to claim 1, wherein a lip of the outer contact seal is brought into surface contact with the seal sliding contact surface.

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