JP2018159464A - Sealed rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sealed deep groove ball bearing capable of holding grease pushed against an inner diameter surface of an outer ring and reducing load in an extraction direction on a seal member, to prevent extraction of the seal member, without increasing an outer ring diameter facing a rolling body.SOLUTION: A grease pocket 14 is provided at a position separate in an axis direction so as not to continue from a raceway groove 4 of an inner diameter surface 2a of an outer ring 2, such that the raceway groove 4 with a sufficient depth can be provided without making a diameter of the inner diameter surface of the outer ring 2 small with respect to a ball 6. Even when grease sealed inside a bearing is pushed against the inner diameter surface 2a of the outer ring 2 due to centrifugal force at high-speed rotation, the grease pushed against the inner diameter surface 2a of the outer ring 2 is held in the grease pocket 14, thereby reducing load in an extraction direction applied to a seal member 10.SELECTED DRAWING: Figure 1

Description

  The present invention relates to measures for preventing a seal seal from coming off due to an increase in bearing internal pressure in a sealed rolling bearing for high-speed rotation.

  In a conventional sealed deep groove ball bearing, the openings of the inner ring and the outer ring are sealed with a seal member in order to prevent leakage of a lubricant such as grease enclosed in the bearing and to prevent foreign matter from entering from the outside.

  However, in deep groove ball bearings used for applications where the outer ring rotates at a high speed of 17,000 or 20,000 rotations per minute, such as flywheel dampers, the centrifugal force during high-speed rotation causes The enclosed grease is pressed against the inner diameter surface of the outer ring, and a large load is applied to the seal member in the pull-out direction.

  For this reason, in the deep groove ball bearing used for the application in which the outer ring rotates at a high speed, it is necessary to take measures for preventing the seal member from coming out.

  Conventionally, as a measure for preventing the seal member from coming off, a core metal of the seal member is made thicker or an overall thickness is made thicker.

  However, if the core of the seal member is made thicker or if the overall thickness is made thicker, there is a problem that the seal member is hindered when incorporated in the seal fitting groove formed on the inner surface of the outer ring.

  Also, if the grease enclosed inside the bearing accumulates more than necessary on the inner surface of the outer ring due to centrifugal force during high-speed rotation, the contact resistance between the outer surface of the cage and the grease increases, increasing the rotational torque and increasing the bearing There is a problem that the temperature rises.

  In the sealed deep groove ball bearing 41 disclosed in Patent Document 1, as shown in FIG. 5, a concave portion 54 continuous from the raceway groove 44 of the outer ring 42 is provided on the inner surface 42 a of the outer ring 42 in the circumferential direction. The grease accumulated on the inner diameter surface 42a is held.

Japanese Patent Laid-Open No. 2006-300261

  However, when the amount of grease that accumulates on the inner surface 42a of the outer ring 42 increases due to centrifugal force during high-speed rotation, if the increased grease is held by the recess 54 that continues from the race groove 44 of the outer ring 42, the race groove 44 In this case, the inner diameter of the outer ring 42 facing the rolling element (ball) 46 is large, that is, the raceway groove 44 is shallow, so that the allowable axial load of the bearing is small and the shoulder resistance is reduced. There arises a problem that the riding effect is reduced.

  Therefore, the present invention holds the grease pressed against the inner surface of the outer ring without increasing the inner diameter of the outer ring facing the rolling element, and reduces the load in the direction of pulling out of the seal member. It is an object of the present invention to provide a sealed rolling bearing that can be prevented.

  In order to solve the above problems, the present invention includes an outer ring, an inner ring, a plurality of rolling elements incorporated between the outer ring and the inner ring, a cage for holding the rolling element, and the outer ring. In a hermetic rolling bearing comprising a seal member that seals the bearing inner space between the inner ring and the inner ring, grease is sealed in the bearing inner space, and the rolling element rolls on the inner diameter surface of the outer ring. And a shoulder provided on the outer side in the axial direction of the raceway groove, and the shoulder is provided with a grease pocket for holding the grease during rotation of the bearing. It is not connected to the raceway groove.

  As described above, according to the present invention, the grease pocket is provided at a position separated in the axial direction so as not to be continuous with the raceway groove on the inner ring surface of the outer ring, so that the diameter of the inner ring surface of the outer ring with respect to the rolling element is not reduced. It is possible to provide a sufficient depth of the raceway groove, so that it is sealed inside the bearing by centrifugal force during high-speed rotation without lowering the allowable axial load of the bearing or lowering the shoulder resistance. Even if the grease is pressed against the inner diameter surface of the outer ring, the grease pressed against the inner diameter surface of the outer ring can be held by the grease pocket, and the load in the pull-out direction applied to the seal member can be reduced.

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 a fracture front view of a flywheel damper to which a sealed type rolling bearing of the embodiment is applied. FIG. 3 is a cross-sectional view taken along line A-O-B in FIG. 2. It is an enlarged view of the C section in FIG. It is a vertical front view which expands and shows a part of sealed type rolling bearing of a prior art example.

  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 type rolling bearing 1 has an outer ring rotating at 12,000 revolutions or more per minute, such as a flywheel damper. Specifically, the outer ring is 17,000 revolutions or 20,000 revolutions per minute. It is used for applications that rotate at a high speed. 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 small-diameter shoulder 2aa, a seal fitting groove 8 and a large-diameter shoulder 2ab are formed on both sides of the inner surface 2a of the outer ring 2 with the raceway groove 4 as a center. Are formed with a pair of seal grooves 9 opposed to the pair of seal fitting grooves 8 in the radial direction.

  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 core metal 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. A radially inner end portion 11b of the cored bar 11 is positioned above a constricted portion 12c of a 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 of the core metal 11.

  An inward lip portion 12d and an outward lip portion 12e are provided on the inner diameter side of the constricted portion 12c. 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.

  As shown in FIG. 1, the sealed rolling bearing 1 according to the present invention is provided with a grease pocket 14 that is recessed outward in the radial direction at a substantially central portion of the small-diameter shoulder 2 aa of the inner surface 2 a of the outer ring 2. The grease pocket 14 is provided at a position away from the raceway groove 4 in the axial direction so as not to be continuous with the raceway groove 4. That is, the grease pocket 14 is continuous with the raceway groove 4 through the connecting surface 15 extending in the axial direction. The connecting surface 15 is a portion corresponding to the end on the raceway groove 4 side in the inner diameter surface of the small diameter shoulder 2aa.

  The size of the grease pocket 14 is preferably large enough to hold 20 to 40% of the amount of grease charged. In this embodiment, as shown in FIG. 1, the depth B is approximately the same as the distance A from the outer diameter surface of the cage 7 to the small diameter shoulder 2aa of the inner diameter surface 2a of the outer ring 2, and the width C is The depth is set to about 1.2 times the depth so that about 30% of the amount of grease can be held.

  If the amount of grease retained in the grease pocket 14 exceeds 40% of the amount of grease charged, specifically, if the depth B of the grease pocket 14 is too deep or the width C is too wide, the amount of grease retained will be excessive. There is a risk that supply of necessary grease to the cage 7 and the balls 6 may be reduced. In addition, when the amount of grease retained in the grease pocket 14 is less than 20% of the amount of grease filled, specifically, when the depth B of the grease pocket 14 is too shallow or the width C is too narrow, the amount of grease retained is small. Too much. Therefore, when the internal pressure of the bearing is increased, the contact area between the grease and the seal member is increased, the load applied to the seal member is increased, and the seal member may be pulled out in the axial direction.

  Further, as described above, the grease pocket 14 is provided at a position separated in the axial direction so as not to be continuous with the raceway groove 4, thereby reducing the diameter of the small-diameter shoulder 2 aa of the inner surface 2 a of the outer ring 2 with respect to the ball 6. The track groove 4 having a sufficient depth can be provided. As a result, even if the grease enclosed in the bearing is pressed against the inner diameter surface 2a of the outer ring 2 by centrifugal force during high-speed rotation without lowering the allowable axial load of the bearing or lowering the shoulder resistance, The grease pressed against the inner diameter surface 2a of the outer ring 2 can be held in the grease pocket 14 to reduce the load in the pull-out direction (axially outer side) applied to the seal member 10.

  In the embodiment shown in FIG. 1, an example in which the grease pocket 14 is formed in one of the small-diameter shoulders 2aa on both sides of the grease pocket 14 with the raceway groove 4 of the outer ring 2 interposed therebetween is shown. The grease pockets 14 may be provided in the small-diameter shoulders 2aa on both sides of the four. When a pair of grease pockets are provided on both sides of the raceway groove 4, the total size of the pair of grease pockets is preferably set to 20 to 40% of the amount of grease filled. Specifically, the total depth of each grease pocket 14 is approximately the same as the distance from the outer diameter surface of the cage 7 to the small-diameter shoulder 2aa of the inner diameter surface 2a of the outer ring 2, and the width of each grease pocket 14 is The total is preferably set to about 1.2 times the depth.

2 to 4 show a support structure for a flywheel damper in which the sealed rolling bearing 1 of this embodiment is used. The upper half of FIG. 3 shows the AO cross section of FIG. 2, and the lower half of FIG. 3 shows the BO cross section of FIG. In this flywheel damper support structure, the flywheel damper 21 is divided into two parts, an engine-side mass 22 and a transmission-side mass 23, and a compression spring 24 and a damping mechanism 25 are provided between them. 23 are mutually supported by the sealed rolling bearing 1 of this embodiment. By using the rolling bearing 1 as a bearing, damping is performed smoothly. Output torque from the engine enters from an engine-side mass 22 directly connected to a crankshaft (not shown), and is transmitted to a driven system via a compression spring 24, a damping mechanism 25, and a transmission-side mass 23. In this case, the compression spring 24 is deflected and the damping mechanism 25 is actuated in accordance with the magnitude of the output torque of the engine, and the torque fluctuation is absorbed by the compression spring 24 and the damping mechanism 25 in this state. 23 rotates with respect to the engine-side mass 22 with the attenuated rotational fluctuation amount. The damping mechanism 25 is formed by an oil chamber 25 a, and rotation transmission performed between the masses 22 and 23 via the compression spring 24 and the damping mechanism 25 is performed via a driven plate 27. The driven plate 27 is coupled to the transmission-side mass 23 by serrations 28 provided on the inner diameter portion. A stopper 29 is provided on the engine-side mass 22 in correspondence with the protrusion 27 a provided on the outer diameter portion of the driven plate 27.

  The sealed rolling bearing 1 is attached to both the masses 22 and 23 as follows. The inner ring 3 is fitted to the outer diameter surface of the cylindrical portion 22a formed on the inner diameter portion of the engine-side mass 22, and is prevented from coming off by a retaining ring 30 fitted to a retaining ring groove formed on the outer diameter surface. . The outer ring 2 is fitted to an inner diameter surface of a cylindrical portion 23a formed on the inner diameter portion of the transmission-side mass 23, and is prevented from coming off by a retaining ring 31 fitted to a retaining ring groove formed on the inner diameter surface. Next, the inner ring 3 is fitted to the outer diameter surface of the cylindrical portion 22 a of the engine-side mass 22, and the retaining ring 30 is used to prevent the inner ring 3 from coming off at the end surface on the counter mating surface side. Then, the engine-side mass 22 and the transmission-side mass 23 are fastened to each other with bolts or the like, and the assembly of the masses 22 and 23 is completed.

  The flywheel damper 21 having the above-described support structure is attached to an engine output shaft (both not shown) by a cylindrical portion 22a so that the engine-side mass 22 is on the engine side.

  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 used for a flywheel damper of an automobile engine. However, the invention is not limited thereto, and is used for a fan coupling device, an alternator, a car air conditioner, a water pump, etc. of an automobile engine. May be.

1: Sealed rolling bearing 2: Outer ring 2a: Inner diameter surface 2aa: Small diameter shoulder 2ab: Large diameter shoulder 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 8: Seal fitting groove 9: Seal groove 10: Seal member 11: Metal core 11a: Radial outer end 11b: Radial inner end 11c: Standing plate 12: Rubber part 12a: fitting portion 12b: body portion 12c: constricted portion 12d: inward lip portion 12e: outward lip portion 14: grease pocket 21: flywheel damper 22: engine side mass 22a: cylindrical portion 23: transmission side mass 23a: Cylindrical portion 24: Compression spring 25: Damping mechanism 25a: Oil chamber 27: Driven plate 27a: Projection 28: Serration 29: Stopper 30: Retaining ring 31: Retaining ring S1:受内 portion space

Claims (5)

An outer ring, an inner ring, a plurality of rolling elements incorporated between the outer ring and the inner ring, a cage that holds the rolling element, and a seal that seals a bearing internal space between the outer ring and the inner ring In a sealed rolling bearing provided with a member,
Grease is enclosed in the bearing internal space,
The inner ring surface of the outer ring is provided with a raceway groove on which the rolling element rolls, and a shoulder provided on the outer side in the axial direction of the raceway groove,
The shoulder is provided with a grease pocket for holding the grease when the bearing rotates.
The grease type pocket bearing is characterized in that the grease pocket is not connected to the raceway groove.   2. The sealed rolling bearing according to claim 1, wherein the grease pocket has a size capable of holding 20% to 40% of the amount of grease charged. 3.   3. The sealed rolling bearing according to claim 1, wherein the grease pocket is provided on shoulders on both sides of a raceway on an inner diameter surface of an outer ring.   3. The sealed rolling bearing according to claim 1, wherein the grease pocket is provided on one of shoulder portions on both sides of the race ring on the inner diameter surface of the outer ring.   The sealed rolling bearing according to any one of claims 1 to 4, which is used for a flywheel damper of an automobile.

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