JP2005256992A - Sealing structure of rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce torque and secure high sealability without using a conventional side plate in a sealing structure of a rolling bearing 1. <P>SOLUTION: In this sealing structure of the rolling bearing 1, a sealing part is formed between the inner peripheral portion of a seal ring 6 mounted on the shoulder part 21 of the outer ring 2 of the rolling bearing 1 and the shoulder part 31 of the inner ring 3 thereof. A plurality of stepwise radially reducing step parts 32 and 33 are formed on the shoulder part 31 of the inner ring 3. The seal ring 6 comprises a cylindrical part 8 and an elastic annular piece 9 formed on the inner periphery of a core 7. The cylindrical part 8 produces a non-contact sealing part in the outer peripheral surface of the shoulder part 31 of the inner ring 3 oppositely to each other through a minute clearance. The elastic annular piece 9 extends in the radial inner direction more than the cylindrical part 8 and comes into the plurality of step parts 32 and 33. A plurality of seal lips 11 to 13 producing the sealing parts between the plurality of step parts 32 and 33 and side faces 32a and 33a along the radial direction thereof are formed on the inner surface of the elastic annular piece 9. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sealing structure in which a sealing portion is formed by a seal ring attached to an inner periphery of a shoulder portion of an outer ring of a rolling bearing and a shoulder portion of the inner ring.

In a rolling bearing, a seal ring is attached to the shoulder portion of the outer ring, and a sealing portion is formed between an inner peripheral portion of the seal ring and a stepped portion provided with a reduced diameter on the shoulder portion of the inner ring. The seal ring includes, for example, an axial lip that forms a non-contact sealing portion on the inner periphery of the core metal, facing the outer peripheral surface of the shoulder portion of the inner ring in a radial direction through a minute gap, and a step portion of the inner ring. A first inner lip that makes a contact sealing portion by contacting the side surface along the radial direction of the portion from the axial direction is attached, and a minute gap is formed on the inner surface of the first inner lip along the radial direction of the stepped portion. Some of them are provided with a second inner lip that forms a non-contact sealing portion opposed to each other in the axial direction. A side plate is provided outside the sealing structure to cover each lip from the outside to enhance the sealing performance (see, for example, Patent Document 1). In this case, the torque can be reduced by providing two non-contact sealing portions and one contact sealing portion, and high sealing performance can be ensured by using the side plates. However, it is pointed out that the cost increases because the side plates are used.
JP-A-10-26143

  An object of the present invention is to reduce torque and secure high sealing performance in a sealing structure of a rolling bearing without using a side plate of a conventional example.

  The present invention relates to a rolling bearing sealing structure in which a sealing portion is formed between an inner peripheral portion of a seal ring attached to a shoulder portion of an outer ring of a rolling bearing and a shoulder portion of the inner ring, and is stepped on the shoulder portion of the inner ring. A cylindrical part that forms a non-contact sealing part by providing a plurality of stepped parts with a reduced diameter on the inner periphery of the metal core and facing the outer peripheral surface of the shoulder of the inner ring in a radial direction through a minute clearance. And an elastic annular piece that extends further inward in the radial direction than the cylindrical portion and enters the plurality of stepped portions, and each of the plurality of stepped portions is provided on an inner surface of the elastic annular piece. A plurality of sealing lips that respectively form sealing portions between the side surfaces along the radial direction are provided.

  According to the present invention, the plurality of step portions provided on the shoulder portion of the inner ring, the cylindrical portion of the seal ring and the elastic annular piece form a bending path from the outside of the bearing to the inside, and the bending path is formed by the cylindrical portion. Since the non-contact sealing part to be made and the plurality of sealing parts made by the plurality of sealing lips of the elastic annular piece are closed, high sealing performance can be secured. In addition, the plurality of seal lips are in contact with the side surface along the radial direction of the step portion from the axial direction to form a contact sealing portion, and are opposed to each other from the axial direction through a minute gap to form a non-contact sealing portion. In any case, the sliding resistance is reduced as compared with the case where the contact seal portion is formed by contacting from the radial direction, which is advantageous in reducing torque.

  Preferably, the sealing lip may be brought into contact with the side surface of the step portion from the axial direction to form a contact sealing portion. As described above, when the seal lip is brought into contact with the side surface along the radial direction of the step portion from the axial direction, the sealing performance is improved as compared with the case of using the non-contact sealing portion, and the contact sealing portion is contacted from the radial direction. The sliding resistance is reduced as compared with the case of manufacturing.

  Preferably, the inner peripheral edge of the elastic annular piece may be opposed in the radial direction through a minute gap so as to form a non-contact sealing portion on the outer periphery of the bottom surface of the step portion having the smallest diameter. Thus, when a non-contact sealing part is further made, sealing performance is further improved.

  Preferably, an annular recess recessed inward of the bearing may be provided on the base side of the outer surface of the elastic annular piece. In this manner, when the annular recess is provided, the elastic annular piece can be made relatively flexible, which helps to make the seal lip lightly contact the stepped portion.

  According to the present invention, torque can be reduced and high sealing performance can be ensured without using the conventional side plate.

  The best embodiment of the present invention will be described with reference to the drawings. 1 is a cross-sectional view showing a sealing structure of a rolling bearing, and FIG. 2 is an enlarged view showing an inner peripheral portion of the seal ring of FIG.

  The rolling bearing 1 shown in the drawing is a deep groove ball bearing, and has a configuration in which a plurality of balls 4 held by a cage 5 are interposed between an outer ring 2 and an inner ring 3. However, the bearing type of the rolling bearing 1 is not particularly limited, such as various ball bearings or roller bearings.

  The rolling bearing 1 is used for supporting a rotor shaft of an alternator attached to an automobile engine, for example, and is used in a high-speed rotation range of tens of thousands to hundreds of thousands of rpm. It can also be used when supporting the rotating shaft of various devices such as.

  A seal ring 6 is attached to one axial direction of the rolling bearing 1. The seal ring 6 may be attached to both ends of the rolling bearing 1 in the axial direction.

  This seal ring 6 has a configuration in which a cylindrical portion 8 protruding inward of the bearing and an elastic annular piece 9 extending further inward in the radial direction than the cylindrical portion 8 are provided on the inner periphery of the cored bar 7. Note that an elastic material 10 such as rubber or resin is applied in a range from the outer periphery to the outer surface of the cored bar 7, and the cylindrical portion 8 and the elastic annular piece 9 are formed of the same material as the elastic material 10. . The seal ring 6 is attached by fitting the outer peripheral portion of the cored bar 7 to the enlarged diameter step portion 22 of the one shoulder portion 21 of the outer ring 2 via the elastic material 10. A sealing part is made on the shoulder 31 side.

  The cylindrical portion 8 serves as a labyrinth seal lip that is opposed to the outer peripheral surface of the shoulder portion 31 of the inner ring 3 from the radial direction through a minute gap to form a non-contact sealing portion. The outer peripheral surface of the cylindrical portion 8 is a tapered surface that decreases in diameter toward the inside of the bearing.

  Three independent seal lips 11 to 13 are provided on the inner side surface of the elastic annular piece 9 from the base side toward the inner peripheral edge. The elastic annular piece 9 enters into a plurality of (two) step portions 32 and 33 provided in the shoulder portion 31 of the inner ring 3 with a diameter reduced stepwise. The three seal lips 11 to 13 form a sealing portion between the large diameter step portion 32 and the small diameter step portion 33. The sealing part formed by these three sealing lips 11 to 13 and the respective step portions 32 and 33 of the inner ring 3 may be a non-contact sealing part or a contact sealing part. For example, a non-contact state having a minute clearance of 0.2 mm or less. To a contact state having a tightening allowance of 0.3 mm or less.

  Specifically, each of the first to third seal lips 11 to 13 is formed so as to protrude toward the inside of the bearing, and the first and second seal lips 11 and 12 are formed of the inner ring 3. The third seal lip 13 is pivoted to the side surface 33a along the radial direction of the small diameter step portion 33 of the inner ring 3 by making contact with the side surface 32a along the radial direction of the large diameter step portion 32 from the axial direction. Contact from the direction to make a contact seal. The second seal lip 12 is opposed to the bottom surface 32b of the large-diameter step portion 32 from the radial direction through a minute gap to form a non-contact sealing portion. The bottom surface 32b of the large-diameter stepped portion 32 is a tapered surface that expands toward the outside of the bearing.

  As described above, in this embodiment, the three seal lips 11 to 13 are made to contact the step portions 32 and 33 from the axial direction. However, any one or more of the three seal lips 11 to 13 may be a labyrinth seal lip that forms a non-contact seal portion facing the step portions 32 and 33 from the axial direction through a minute gap. Good.

  In addition, the inner peripheral edge 14 of the elastic annular piece 9 is opposed to the bottom surface 33b of the small diameter step portion 33 of the inner ring 3 from the radial direction through a minute clearance so as to form a non-contact sealing portion. The inner peripheral edge 14 of the elastic annular piece 9 may be brought into contact with the bottom surface 33b of the small diameter step portion 33 of the inner ring 3 from the radial direction so as to form a contact sealing portion.

  Further, an annular recess 15 that is recessed inward of the bearing is provided on the base side of the outer surface of the elastic annular piece 9. If the annular recess 15 is provided, the elastic annular piece 9 can be made relatively flexible, which is useful for lightly contacting the three seal lips 11 to 13 with the step portions 32 and 33. The outer diameter side peripheral surface 15a that forms the annular recess 15 is formed in a tapered shape that gradually increases in diameter toward the outside. If this outer diameter side peripheral surface 15a is tapered, when foreign matter such as moisture or dust enters the annular recess 15, they can be efficiently discharged from the annular recess 15 to the outside by the rotational centrifugal force. Therefore, it is useful for preventing or suppressing foreign matter remaining in the annular recess 15.

  According to the sealing structure of the rolling bearing 1 described above, the non-contact sealing portion formed by the inner peripheral edge 14 of the elastic annular piece 9 and the bottom surface 33b of the small-diameter step portion 33 and the three seals from the bearing outer side to the inner side. Since three contact sealing portions made by the lips 11 to 13 and the side surfaces 32a and 33a of the two step portions 32 and 33 and a non-contact sealing portion made by the cylindrical portion 8 and the shoulder portion 31 are provided. The sealability can be secured, and the three seal lips 11 to 13 are of the axial contact type, so that the sliding resistance is remarkably smaller than that of the radial contact type, and the torque can be reduced. it can.

Sectional drawing which shows the sealing structure of the rolling bearing which concerns on one Embodiment of this invention. The figure which expands and shows the inner peripheral part of the seal ring of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Outer ring 3 ... Inner ring 6 ... Seal ring 8 ... Cylindrical part (labyrinth seal lip)
DESCRIPTION OF SYMBOLS 9 ... Elastic annular piece 11 ... 1st seal lip 12 ... 2nd seal lip 13 ... 3rd seal lip 31 ... Shoulder part of inner ring 32 ... Large diameter step part 32a of inner ring 32b ... Side surface of large diameter step part 32b ... Bottom surface of large diameter step portion 33 ... Small diameter step portion of inner ring 33a ... Side surface of small diameter step portion 33b ... Bottom surface of small diameter step portion

Claims (4)

A rolling bearing sealing structure for forming a sealing portion between an inner peripheral portion of a seal ring attached to a shoulder portion of an outer ring of a rolling bearing and a shoulder portion of the inner ring,
Provided with a plurality of stepped portions that gradually reduce the diameter of the shoulder of the inner ring,
A cylindrical portion that forms a non-contact sealing portion on the inner periphery of the core metal, facing the outer peripheral surface of the shoulder portion of the inner ring through a small clearance in the radial direction, and further radially inward than the cylindrical portion. An elastic annular piece extending in the direction and entering the plurality of step portions is provided, and is sealed between the inner side surface of the elastic annular piece and the side surface along the radial direction of each of the plurality of step portions. A rolling bearing sealing structure characterized in that a plurality of sealing lips for forming a portion are provided.   2. The rolling bearing sealing structure according to claim 1, wherein the sealing lip is brought into contact with a side surface of the step portion in the axial direction to form a contact sealing portion.   2. The rolling bearing according to claim 1, wherein the inner peripheral edge of the elastic annular piece is opposed to the outer periphery of the bottom surface of the smallest diameter step from the radial direction through a minute clearance so as to form a non-contact sealing portion. Sealing structure.   4. The rolling bearing sealing structure according to claim 1, wherein an annular recess recessed inward of the bearing is provided on a base side of an outer surface of the elastic annular piece.

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