Bearing sealing device and bearing sealing mechanism capable of preventing the leakage of grease

Abstract

There is provided a bearing sealing device capable of substantially completely preventing a leak of grease. A taper end portion of an axial extension of the bearing sealing device has an opposite surface and a rake face that forms a specified rake angle with the opposite surface. The opposite surface forms a narrow passage between the opposite surface and an outer peripheral surface of an inner ring. The narrow passage allows air to pass easily, but it allows grease to hardly pass therethrough. Further, the axial extension includes part of a core metal that extends axially and has its foremost end located axially inside an axial outermost end of the outer peripheral surface of the inner ring. Grease moving axially outwardly on the outer peripheral surface is moved along the rake face of the taper end portion and then guided along a cover portion of the bearing sealing device to an outer ring. The part of the core metal prevents the axial extension from being bent radially outwardly by a centrifugal force.

What is claimed is: 
     
       1. A .Iadd.bearing sealing mechanism for a bearing including an outer ring and an inner ring in which the outer ring rotates, and rolling members arranged between the outer ring and the inner ring, said bearing sealing mechanism comprising: a .Iaddend.bearing sealing device which is provided between .[.an.]. .Iadd.the .Iaddend.outer ring and .[.an.]. inner ring .[.of a bearing in which the outer ring rotates.]., seals a space between the outer ring and the inner ring, and is securely fixed to the outer ring so as to rotate together with the outer ring, .Iadd.said bearing sealing device .Iaddend.comprising:   a fixed portion fixed to the outer ring;   a cover portion which extends in a radially inward direction of the outer ring from the fixed portion and covers the space between the outer ring and the inner ring; and   an axial extension which is made of an elastic material and extends in an axially inward direction of the outer ring from the cover portion, wherein   the axial extension includes a taper end portion having an opposite surface which is opposed to an outer peripheral surface of the inner ring and forms between the opposite surface and the outer peripheral surface of the inner ring a narrow passage having a specified narrowness such that air is allowed to pass comparatively easily and oil is allowed to pass comparatively hardly, and a rake face forming a specified rake angle with the opposite surface; and the fixed portion, the cover portion and the axial extension respectively include part of a core metal, said core metal extending axially inwardly from the cover portion up to a position on a radially outer side of the outer peripheral surface of the inner ring, where a foremost end of the core metal is positioned in the vicinity of the taper end portion.Iadd..[.;.]. .Iaddend.and   a retainer which holds the rolling members arranged between the outer ring and the inner ring axially inwardly with respect to the axial extension wherein   said retainer has a configuration such that a distance L1 between the retainer and the rake face of the taper end portion of the axial extension is larger than a distance L2 (L1>L2) between the retainer and the outer peripheral surface of the inner ring.   
     
     
       2. A bearing sealing .[.device.]. .Iadd.mechanism .Iaddend.as claimed in claim 1, wherein the taper end portion comprises at its axial innermost end a recess portion which is recessed radially outwardly from the opposite surface that forms the narrow passage and recessed axially outwardly from a foremost end of the rake face. 
     
     
       3. A bearing sealing .[.device.]. .Iadd.mechanism .Iaddend.as claimed in claim 1, wherein the axial extension comprises: a recess portion which is located axially outwardly with respect to the taper end portion and recessed radially outwardly with respect to the opposite surface of the taper end portion.   
     
     
       4. A bearing sealing .[.device.]. .Iadd.mechanism .Iaddend.as claimed in claim 1, wherein the part of the core metal in the axial extension has an annular configuration existing continuously around an entire outer periphery of the inner ring. .[. 
     
     
       5.  A bearing sealing mechanism comprising: a bearing sealing device as claimed in claim 1; and   a crown-shaped retainer which is made of resin and holds rolling members arranged between the outer ring and the inner ring, wherein said retainer has a projection including an opposite surface that is provided oppositely to the outer peripheral surface of the inner ring axially inwardly with respect to the taper end portion, and forms between the opposite surface and the outer peripheral surface of the inner ring a narrow passage having a specified narrowness such that air is allowed to pass comparatively easily and oil is allowed to pass comparatively hardly..]..[.6. A bearing sealing mechanism comprising:     a bearing sealing device as claimed in claim 1; and   a retainer which holds rolling members arranged between the outer ring and the inner ring axially inwardly with respect to the axial extension, wherein said retainer has a configuration such that a distance L1 between the retainer and the rake face of the taper end portion of the axial extension is set not smaller than a distance L2 (L1≧L2) between the retainer and the outer peripheral surface of the inner ring..]..[.7. A bearing sealing mechanism comprising:     a bearing sealing device which is provided between an outer ring and an inner ring of a bearing in which the outer ring rotates, seals a space between the outer ring and the inner ring, and is securely fixed to the outer ring so as to rotate together with the outer ring; and   a retainer which holds rolling members arranged between the outer ring and the inner ring axially inwardly with respect to the bearing sealing device, wherein said bearing sealing device has     a fixed portion fixed to the outer ring   a cover portion which extends radially inwardly from the fixed portion and covers a space between the outer ring and the inner ring, and   a seal portion which extends radially inwardly and axially inwardly from the cover portion toward an outer peripheral surface of the inner ring, said seal portion having an opposite surface which is opposed to the outer peripheral surface of the inner ring, and forms between the opposite surface and the outer peripheral surface of the inner ring a narrow passage having a specified narrowness such that air is allowed to pass comparatively easily and oil is allowed to pass comparatively hardly, and wherein   said retainer has a configuration such that a distance D1 between the retainer and the seal portion is set not smaller than a distance D2 (D1≧D2) between the retainer and the outer peripheral surface of the inner ring..].