JP2018145975A - Sealed rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent grease from leaking from an air inflow gap formed on a contact surface between a raceway ring and a seal member and foreign matter from the outside of the bearing in a sealed rolling bearing, and to enter the seal member into the raceway ring. Prevents adsorption. SOLUTION: An outer ring 2, an inner ring 3, a fitting portion 12a to be fitted into a pair of seal fitting grooves 8 provided at both ends of an inner diameter surface of the outer ring 2, and both ends of the outer diameter surface of the inner ring 3. In a sealed rolling bearing 1 provided with a sealing member 10 having lip portions 12e and 12d that are elastically contacted with a pair of formed sealing grooves 9, the sealing member 10 penetrates the inside of the bearing and the outside of the bearing. A through hole 14 for adjusting the pressure difference between the bearing internal space S1 and the bearing external space S2 is provided while preventing water from entering. [Selection diagram] Fig. 1

Description

  The present invention relates to a sealed type rolling bearing that is required to have water resistance and grease leakage resistance, such as an automobile auxiliary machine.

  In conventional sealed type rolling bearings, the openings of the inner ring and the outer ring are sealed with a sealing member to prevent leakage of grease and other lubricants enclosed in the bearing and to prevent foreign substances (such as muddy water) from entering. Has been.

  However, when the bearing temperature rises and the internal pressure increases, and then the bearing temperature decreases (returns to normal temperature), the balance between the internal pressure and the pressure outside the bearing (atmospheric pressure) is lost. Specifically, the internal pressure of the bearing decreases with respect to the atmospheric pressure. That is, the internal pressure of the bearing is negative with respect to the outside. When the internal pressure of the bearing decreases, the seal member is deformed, and the seal member is attracted to the race. When such adsorption of the seal member occurs, the seal member sticks to the rotating part (inner ring or outer ring), which increases torque and requires attention to the occurrence of wear on the seal member. is there.

  Conventionally, in order to prevent the seal member and the bearing ring from adsorbing, an air inflow gap has been provided in the contact portion between the seal member and the race, and when the bearing interior becomes negative pressure, Patent Document 1 or Patent Document 2 discloses a sealed-type rolling bearing in which a decrease in internal pressure inside the bearing is suppressed by introducing air to prevent the seal member from adsorbing to the race ring.

  As shown in FIGS. 4 to 5, the sealed rolling bearing 21 </ b> A of Patent Document 1 is provided with a pair of seal fitting grooves 28 </ b> A at both ends of the inner surface of the outer ring 22 </ b> A, and a seal member is provided in the pair of seal fitting grooves 28 </ b> A. The outer diameter portion of 30A is fitted, and the tip portion of the inward lip 32A formed on the inner peripheral portion of the seal member 30A is elastically applied to the inner surface of the seal groove 29A formed at both outer diameter surface ends of the inner ring 23A. It is a sealed type that seals the bearing space by contacting.

  The sealed rolling bearing 21A of Patent Document 1 includes a gap between at least a part of the inward lip 32A in the circumferential direction of a contact surface that elastically contacts the inner surface 29a of the seal groove 29A. A recess 38 is provided as an air inflow gap that forms a minute air gap, and when the inside of the bearing becomes negative pressure, air is caused to flow into the bearing from the recess 38 of the air inflow gap, thereby reducing the internal pressure inside the bearing. This prevents the seal member 30 from adsorbing to the inner ring 23.

  Further, as shown in FIGS. 6 to 7, the sealed rolling bearing 21 </ b> B of Patent Document 2 has an outer diameter of a seal member 30 </ b> B that fits in a pair of seal fitting grooves 28 </ b> B provided at both ends of the inner diameter surface of the outer ring 22 </ b> B. The slit 40 is provided as an air inflow gap in the portion, and when the inside of the bearing becomes negative pressure, air is caused to flow into the bearing from the slit 40, thereby suppressing a decrease in the internal pressure inside the bearing and the seal member 30B becomes the outer ring 22B. To prevent adsorption.

JP 2011-236983 A JP 2011-47468 A

  However, as described above, if a concave portion or slit, which is an air inflow gap, is provided on the contact surface between the seal member and the bearing ring, grease inside the bearing leaks from the concave portion or slit, or foreign matter enters from the outside of the bearing. There is a fear.

  Accordingly, the present invention provides a seal-type rolling bearing having a seal member raceway while preventing leakage of grease from the air inflow gap formed on the contact surface between the race ring and the seal member and entry of foreign matter from the outside of the bearing. An object is to prevent adsorption to the ring.

  In order to solve the above-described problems, the present invention provides an outer ring, an inner ring, a fitting portion that fits into a pair of seal fitting grooves provided at both ends of the inner diameter surface of the outer ring, and an outer diameter surface of the inner ring. In a sealed type rolling bearing provided with a seal member having a lip portion elastically contacting a pair of seal grooves formed at both ends, the seal member penetrates the inside of the bearing and the outside of the bearing to prevent water intrusion. However, a through hole for adjusting a pressure difference between the bearing inner space and the bearing outer space is provided.

  The sealed rolling bearing according to the present invention has a through hole that adjusts a pressure difference between the bearing inner space and the bearing outer space while penetrating the bearing inside and the bearing outer and preventing water intrusion. It is possible to prevent the seal member from adsorbing to the race wheel while preventing water from entering.

It is a vertical front view which expands and shows a part of sealed-type rolling bearing which concerns on one form of this invention. It is sectional drawing which expands and shows the sealing member of FIG. It is sectional drawing which showed the pulley using the sealing type rolling bearing shown in FIG. It is a vertical front view which expands and shows a part of sealed type rolling bearing of a prior art example. It is sectional drawing which expands and shows the inward lip | rip part of FIG. It is a vertical front view which expands and shows a part of sealed type rolling bearing of another conventional example. It is sectional drawing which expands and shows the seal | sticker fitting part of FIG.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  As shown in FIG. 1, the sealed rolling bearing 1 includes an outer ring 2, an inner ring 3, a raceway groove 4 formed on the inner diameter surface of the outer ring 2, and a raceway groove 5 formed on the outer diameter surface of the inner ring 3. A plurality of balls 6 incorporated in the holder 6 and a holder 7 for holding the balls 6. The outer ring 2, the inner ring 3, the ball 6 and the cage 7 are metal members. In the present embodiment, the cage 7 is made of iron, but may be made of resin. The sealed rolling bearing 1 of the present embodiment is a deep groove ball bearing. Further, the sealed rolling bearing 1 is a bearing for an automobile auxiliary machine used for an automobile auxiliary machine such as an idler pulley described later. In the following description, a direction along the central axis of the sealed rolling bearing 1 is referred to as an “axial direction”, and a direction orthogonal to the central axis is referred to as a “radial direction”.

In the sealed rolling bearing 1, the inner ring 3 is fixed and the outer ring 2 rotates. That is, the sealed rolling bearing 1 is an outer ring rotating bearing. Grease (not shown) is sealed in the bearing internal space S1 of the sealed rolling bearing 1. Here, the bearing inner space S <b> 1 means a space between the inner diameter surface 2 a of the outer ring 2 and the outer diameter surface 3 a of the inner ring 3. The kinematic viscosity of the grease is preferably 10 to 250 cSt (mm ² / s) at 40 ° C., more preferably 30 to 75 cSt at 40 ° C. By setting the kinematic viscosity of the grease to 30 to 75 Cst, it is easy to form a lubricating oil film having a required thickness.

  A pair of seal fitting grooves 8 are formed at both ends in the axial direction on the inner diameter surface 2a of the outer ring 2, while the outer diameter surface 3a of the inner ring 3 is formed radially with the pair of seal fitting grooves 8 in the radial direction. A pair of opposed seal grooves 9 are formed. The outer diameter surface 3a of the inner ring 3 has a large diameter shoulder 3aa and a small diameter shoulder 3ab. The large-diameter shoulder 3aa is located on the outer side in the axial direction than the rolling surface (track groove 5) of the inner ring 3. The small diameter shoulder 3ab has a smaller diameter than the large diameter shoulder 3aa, and the outer diameter surface thereof is located on the inner diameter side of the large diameter shoulder 3aa. The seal groove 9 is provided between the large-diameter shoulder 3aa and the small-diameter shoulder 3ab.

  In each of the pair of seal fitting grooves 8 formed in the outer ring 2, the outer diameter portion of the seal member 10 is fitted. The seal member 10 includes a metal core 11 and a rubber portion 12 formed integrally with the metal core 11.

  The cored bar is made of metal and has an annular shape when viewed from the axial direction. The radially outer end 11a of the cored bar 11 is bent toward the inner side in the axial direction. The radially outer end portion 11a of the cored bar 11 faces the seal fitting groove 8 in the axial direction. The radially inner end portion 11b of the cored bar 11 is located below the inner diameter surface 7a of the cage 7 and above the constricted portion 12c of the rubber portion 12 described later. Between the radial outer end portion 11a and the radial inner end portion 11b of the core metal 11, a standing plate portion 11c extending in the radial direction is provided.

  The rubber portion 12 is annular when viewed from the axial direction. The rubber portion 12 is made of rubber having excellent oil resistance and heat resistance, such as nitrile rubber, heat-resistant nitrile rubber, hydrogenated nitrile rubber, acrylic rubber, and fluorine rubber. The rubber portion 12 is integrally formed by vulcanization molding on the core metal 11. The rubber portion 12 covers the entire core metal 11 excluding the inner surface of the standing plate portion 11 c of the core metal 11.

  As shown in FIGS. 1 and 2, the rubber portion 12 has a fitting portion 12a, a main body portion 12b, a constricted portion 12c, an inward lip portion 12d, and an outward lip portion 12e. . The fitting portion 12 a is a portion that is fitted in the seal fitting groove 8 and covers the radially outer end portion of the core metal 11. The main body portion 12b is a portion located between the fitting portion 12a and a constricted portion 12c described later. The main body portion 12b is a portion that is located on the inner diameter side of the fitting portion 12a and covers a portion of the core metal 11 excluding the radially outer end portion 11a.

  The constricted portion 12c is a portion located on the inner diameter side with respect to the radially inner end portion of the main body portion 12b. That is, the constricted portion 12 c is located on the inner diameter side with respect to the radially inner end portion 11 b of the core metal 11. The constricted portion 12 c is located between the inner diameter surface 7 a of the cage 7 and the outer diameter surface 3 a of the inner ring 3. The constricted portion 12c includes a first constricted portion 12ca extending inward in the axial direction from the radially inner end of the main body portion 12b, and a second constricted portion 12cb extending from the first constricted portion 12ca to the inner diameter side.

  The first constricted portion 12ca has an axial dimension that gradually decreases toward the inner diameter side. A through hole (hereinafter also referred to as a micro through hole) 14 to be described later is formed in the first constricted portion 12ca. The second constricted portion 12cb has an axial dimension smaller than that of the first constricted portion 12ca. The axial dimension of the second constricted portion 12cb is substantially equal from the outer diameter side toward the inner diameter side. The second constricted portion 12 cb is a portion that is most easily elastically deformed in the rubber portion 12.

  An inward lip portion 12d and an outward lip portion 12e are provided on the inner diameter side of the constricted portion 12c (the second constricted portion 12cb). That is, the constricted portion 12c is provided on the outer diameter side of the inward lip portion 12d and the outward lip portion 12e. The inward lip portion 12 d is in contact with the inner surface of the seal groove 9. The outward lip portion 12e is provided on the outer side in the axial direction than the inward lip portion 12d, and is in contact with the small-diameter shoulder portion 3ab formed outward in the axial direction of the seal groove 9.

  The inward lip portion 12d and the outward lip portion 12e are formed on the inner diameter portion of the seal member 10 via a constricted portion 12c.

  The first constricted portion 12ca is formed with a through hole 14 that penetrates the bearing inner space S and the bearing exterior. The through hole 14 extends in the axial direction. The through hole 14 is provided in the vicinity of the portion having the smallest axial dimension in the rubber portion 12, and specifically, is located on the outer diameter side (above the paper surface) of the second constricted portion 12 cb.

  The sealed rolling bearing 1 of the present embodiment is used as a rolling bearing for an automobile auxiliary machine. As an example of an automobile accessory, an idler pulley used as a belt tensioner for a drive belt of an automobile accessory is shown in FIG. FIG. 3 is a cross-sectional view of the structure of the idler pulley. An idler pulley (hereinafter simply referred to as a pulley) guides a driving belt of an auxiliary vehicle such as an alternator or a compressor.

  As shown in FIG. 3, the pulley includes a steel plate pulley main body 51 and a sealed rolling bearing 1 fitted to the inner diameter of the pulley main body 51. The pulley body 51 and the sealed rolling bearing 1 constitute a pulley bearing. The pulley body 51 is an annular body. The pulley body 51 includes an inner diameter cylindrical portion 51a, a flange portion 51b extending outward from one end of the inner diameter cylindrical portion 51a, an outer diameter cylindrical portion 51c extending in the axial direction from the flange portion 51b, and the other end of the inner diameter cylindrical portion 51a. And a flange portion 51d extending to the inner diameter side. The outer ring 2 of the sealed rolling bearing 1 is fitted to the inner diameter of the inner diameter cylindrical portion 51a, and the outer peripheral diameter of the outer diameter cylindrical portion 51c is provided with a pulley peripheral surface 51e that contacts a belt driven by the engine. . By bringing the pulley peripheral surface 51e into contact with the belt, the pulley serves as an idler.

  In rolling bearings (outer ring rotation bearings) used in pulley bearings as shown in FIG. 3, water resistance requirements (specifically, muddy water requirements) are increasing in preparation for a case where an automobile travels on a rough road. Yes.

  Moreover, the pulley bearing is often used under the condition of high speed rotation. For this reason, the centrifugal force acting on the grease increases, and the grease is likely to leak into the bearing outer space. Further, since it is used at high speed rotation, it is conceivable that grease leaks to the bearing outer space due to rubber deterioration due to an increase in bearing temperature. Thus, the pulley bearing requires a countermeasure against grease leakage.

  Furthermore, in recent years, along with the space saving of automobiles, there is a tendency to reduce the inner diameter of the pulley while maintaining the size of the rolling bearing. Since there is no change in the engine speed itself, only the ratio between the engine crank and pulley increases, and as the pulley speed increases, the rotational speed of the rolling bearing also increases. Tend to be used below. Therefore, in the pulley bearing, the bearing temperature is likely to increase, and the internal pressure is likely to increase. Thereafter, when the temperature of the bearing inner space returns to room temperature, the internal pressure tends to be negative with respect to the bearing outer space. Therefore, not only leakage of grease but also prevention of adsorption of the seal member to the race wheel due to the negative internal pressure of the pulley bearing is required.

  Therefore, in the pulley bearing 1 of the present embodiment used for a pulley, a seal is provided between the outer ring 2 and the inner ring 3 in order to prevent foreign matter (here, water such as muddy water) from entering the bearing internal space S1. A member 10 is provided. Thereby, the water resistance of the pulley bearing 1 can be increased.

  Further, a through hole 14 is provided in the constricted portion 12 c of the rubber portion 12 of the seal member 10. The through hole 14 is a vent hole that adjusts a pressure difference between the bearing internal space (hereinafter simply referred to as the bearing inside) S1 and the bearing external space (hereinafter simply referred to as the bearing outside) S2. Here, when there is no pressure difference between the bearing interior S1 and the bearing exterior S2, the through hole 14 is closed by the elastic force of the seal member 10, and a pressure difference is generated between the bearing interior S1 and the bearing exterior S2. And the size of the extent which opens with the pressure difference is desirable. Specifically, the outer diameter of the through hole 14 is preferably set to 100 μm or less, and preferably set to 10 μm or more and 80 μm or less. As described above, when a pressure difference is generated between the bearing interior S1 and the bearing exterior S2, air is caused to pass through the minute through hole 14, so that the pressure difference between the bearing interior S1 and the bearing exterior S2 is eliminated and the seal is sealed. The member 10 can be prevented from adsorbing to the race wheel (the inner ring 3 and the outer ring 2).

  In addition, the through hole 14 is sealed in the bearing interior S1 by forming the through hole 14 so as to be small enough to open the through hole 14 when a pressure difference occurs between the bearing interior S1 and the bearing exterior S2. It is possible to prevent leakage of grease to the outside of the bearing S2 and intrusion of muddy water from the outside of the bearing S2.

  In order to facilitate opening and closing of the through hole 14 by elastic deformation of the rubber portion 12, the position of the through hole 14 is preferably the constricted portion 12c of the seal member 10 where the seal member 10 is easily elastically deformed. More preferably, it is formed in the vicinity of the second constricted part 12cb that is most easily elastically deformed in the constricted part 12c, specifically, in the first constricted part 12ca on the outer diameter side (above the paper surface) of the second constricted part 12cb. It is preferable. By forming the through hole 14 in the first constricted portion 12ca, the axial dimension of the through hole 14 can be increased, and muddy water is less likely to enter the bearing interior S1. That is, it is possible to prevent the seal member 10 from adsorbing to the race wheel while further improving the water resistance of the sealed rolling bearing 1.

  Further, in order to make it easier to prevent the intrusion of foreign matter from the outside of the bearing S2, the diameter of the through hole 14 is formed so that the outside of the bearing S2 is narrower than the inside of the bearing S1 as shown in the enlarged view of FIG. It is preferable to keep it. That is, the through hole 14 of the present embodiment is tapered from the bearing interior S1 toward the bearing exterior S2.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  In the above-described embodiment, the sealed rolling bearing 1 is a bearing that supports an idler pulley, but is not limited thereto, and may be a bearing that supports another belt transmission, and is pressed by a hydraulic auto tensioner. Thus, it may be a bearing that supports a tension pulley that absorbs fluctuations in belt tension. Further, the sealed rolling bearing 1 may be used in other automobile auxiliary machines. For example, the sealed rolling bearing 1 may be used for a fan coupling device for an automobile engine, an alternator, a flywheel damper for an automobile engine, a car air conditioner, a water pump, and the like.

  Further, the through hole 14 is not limited to the first constricted portion 12ca, and may be formed in the second constricted portion 12cb.

1: Sealed type rolling bearing 2: Outer ring 2a: Inner diameter surface 3: Inner ring 3a: Outer diameter surface 3aa: Large diameter shoulder 3ab: Small diameter shoulder 4: Track groove 5: Track groove 6: Ball 7: Cage 7a: Inner diameter Surface 8: Seal fitting groove 9: Seal groove 10: Seal member 11: Core metal 11a: Radial outer end portion 11b: Radial inner end portion 12: Rubber portion 12a: Fitting portion 12b: Main body portion 12c: Constriction Portion 12ca: First constriction portion 12cb: Second constriction portion 12d: Inward lip portion 12e: Outward lip portion 14: Through hole 51: Pulley body 51a: Inner diameter cylindrical portion 51b: Flange portion 51c: Outer diameter cylindrical portion 51d: Flange 51e: pulley peripheral surface S1: bearing inner space S2: bearing outer space

Claims (6)

Elastic contact with an outer ring, an inner ring, a fitting portion that fits into a pair of seal fitting grooves provided at both ends of the inner ring surface of the outer ring, and a pair of seal grooves formed at both ends of the outer ring surface of the inner ring In a sealed rolling bearing provided with a seal member having a lip portion to be
The seal member is provided with a through-hole that adjusts a pressure difference between the bearing inner space and the bearing outer space while penetrating the bearing inner portion and the bearing outer portion to prevent water intrusion. .   The sealed rolling bearing according to claim 1, wherein the seal member includes a cored bar and a rubber part integrally formed with the cored bar, and the through hole is formed in the rubber part. The rubber portion has the fitting portion, the lip portion, and a constricted portion provided on the outer diameter side of the lip portion,
The sealed rolling bearing according to claim 2, wherein the through hole is formed in the constricted portion. The rubber portion further includes a main body portion that is located between the fitting portion and the constricted portion and covers the cored bar,
The constricted portion includes a first constricted portion located on the inner diameter side of the main body portion, and a second constricted portion having a smaller axial dimension than the first constricted portion,
The sealed rolling bearing according to claim 3, wherein the through hole is formed in the first constricted portion.   The sealed type rolling bearing according to claim 1, wherein an outer diameter of the through hole is formed so that a bearing outer side is narrower than a bearing inner side.   The hermetic rolling bearing according to claim 1, which is used for a rolling bearing for an automobile auxiliary machine.

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