JP2012163148A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing capable of reducing seal torque and preventing intrusion of a foreign object, with respect to a rolling bearing which rotatably supports a pulley used under oil lubrication.SOLUTION: The rolling bearing is a bearing incorporated in the pulley used under oil lubrication to rotatably support the pulley. The seal member 5 is a contact seal with its base end fixed to an outer ring 2 and its seal lip part 15 contacting an inner ring 1. The seal lip part 15 includes a body part 15a and an edge part 15b projecting from an inner peripheral edge of the body part 15a and contacting the inner ring 1. A material of at least the edge part 15b is an easily wearable high wear material which is worn away to be non-contact or to be soft-contact at a degree that the contact pressure can be regarded to be zero by using the bearing in a rotating state.

Description

  The present invention relates to a rolling bearing used for, for example, an automobile idler pulley, tensioner pulley, and the like, and more particularly, to a rolling bearing used for various pulleys for timing belts used under oil lubrication.

  Conventional timing belt systems have been used with grease lubrication but not with oil lubrication. In recent years, with the advent of high-strength belts and the trend toward lighter weight and lower fuel consumption, replacement of the timing chain system with the timing belt system has occurred, and there are cases where the belt is applied in an oil bath. When used in an oil bath, a pulley suitable for oil lubrication is required as compared with a conventional pulley.

JP 2010-019296 A

A contact type seal may be used for a bearing used under oil lubrication in order to prevent foreign matter from entering the bearing. In this case, intrusion of foreign matter can be prevented, but the torque is large because the resistance of the seal lip is large.
Here, the present applicant has proposed, for example, a bearing that prevents foreign matter from entering and has a low torque as a bearing used in an automobile transmission or the like (Patent Document 1). The seal used in this bearing is made of a highly wearable material at the tip of the lip, and the tip of the lip is worn during rotation of the seal that was a contact type in the initial stage of operation to form the optimum labyrinth clearance. By doing so, it becomes a non-contact seal in actual use, realizing low torque and low fuel consumption.

  An object of the present invention is to provide a rolling bearing that can reduce a sealing torque and prevent foreign matter from entering a rolling bearing that rotatably supports a pulley used under oil lubrication.

A rolling bearing according to the present invention is a rolling bearing which is incorporated in a pulley used under oil lubrication and rotatably supports the pulley, and includes a plurality of rolling elements interposed between inner and outer rings and raceway surfaces of the inner and outer rings. And a rolling bearing provided with a seal member that seals a bearing space formed between the inner and outer rings, the seal member is a contact seal in which a base end is fixed to the outer ring and a seal lip portion is in contact with the inner ring, The seal lip portion includes a main body portion and a tip portion that protrudes from an inner peripheral edge of the main body portion and contacts the inner ring, and at least the material of the tip portion is worn by using the bearing in a rotating state. It is a high-abrasion material that is non-contact or has a light contact that can be regarded as having zero contact pressure.
The “high wear material” is a material that easily wears.

  According to this configuration, for the rolling bearing incorporated in the pulley used under oil lubrication, the material of the tip portion of the seal lip portion is made of a high wear material as described above. However, due to wear, it becomes a non-contact or light contact type seal member early after operation. That is, the seal torque can be reduced sufficiently and quickly by wearing the tip portion of the seal lip portion. In addition, due to the wear of the seal member, a minute optimum labyrinth gap is formed between the seal lip portion and the inner ring as an optimum non-contact seal gap or a light contact seal gap. By forming the optimum labyrinth gap, the following effects can be obtained.

(1). Seal torque is reduced.
(2). The self-heating of the bearing is lower than the conventional product.
(3). By lowering the self-heating of the bearing, it is possible to select an oil having a lower viscosity than the conventional oil.
(4). Loss of the timing belt system can be reduced by reducing the sealing torque and selecting low viscosity oil.
(5). The labyrinth clearance allows oil to pass into the bearing, but it can prevent the entry of foreign matter with a large particle size that affects the bearing life.

The high wear material may be a rubber material or a resin material.
The high wear material may be a rubber material, and the seal member may be formed by vulcanization molding of the rubber material.
The high wear material may be a resin material, and the seal member may be formed by injection molding the resin material.

The contact force of the seal lip portion with respect to the inner ring may be 11N or more. The contact force of the seal lip varies depending on various factors, but if a certain amount of contact force is applied, the seal lip can be worn early after operation. From the evaluation test, it was found that the tip portion of the seal lip portion was worn early after operation by setting the contact force of the seal lip portion to 11 N or more.
The surface roughness of the seal contact surface in the inner ring may be Ra 1.0 μm or more. In this case, the front end portion of the seal lip portion can be worn early after operation.

The seal lip portion of the seal member may be shaped to contact the inner ring in the radial direction.
When the seal lip portion is shaped to contact in the radial direction, the tip portion of the seal lip portion may protrude from the inner side edge of the inner peripheral edge of the main body portion and contact the inner ring. In this case, the rigidity of the seal member can be increased as compared with the case where the tip end portion of the seal lip portion is provided on the outer side in the axial direction or in the middle of the main body portion. As a result, the seal lip portion is unlikely to warp outward in the axial direction, and a strong contact force can be applied to the seal lip portion. Therefore, the tip portion of the seal lip portion can be worn early after operation.

  The seal contact surface where the tip portion of the seal lip portion contacts the inner ring may be the outer diameter surface of the inner ring. In this case, the overall length of the seal member can be shortened as compared with a configuration in which a seal groove is formed on the outer diameter surface of the inner ring and the inner ring seal groove is used as a seal contact surface. Therefore, it is possible to increase the rigidity of the seal member as compared with the seal member corresponding to the inner ring seal groove, and to apply a strong contact force to the seal lip portion by operating the bearing. Therefore, the tip portion of the seal lip portion can be worn early after operation.

  The seal lip portion of the seal member may be shaped to contact the inner ring in the axial direction.

The seal member includes an annular cored bar and an elastic member provided integrally with the cored bar, and the elastic member has an inner peripheral part of an elastic member extending to an inner diameter side with respect to the inner peripheral edge of the cored bar. In addition, the inner peripheral portion of the inner peripheral portion of the elastic member may be the seal lip portion, and the radial height of the inner peripheral portion of the elastic member may be equal to or less than the axial thickness of the main body portion of the seal lip portion.
In this case, the radial height of the elastic member inner peripheral portion having low rigidity among the elastic members can be made shorter than that of the prior art. Therefore, the rigidity of the seal member can be increased as compared with the conventional one, and a strong contact force can be applied to the seal lip portion. Therefore, the tip portion of the seal lip portion can be more reliably and quickly worn.

  A non-contact seal lip portion that extends from the main body portion of the seal lip portion and does not contact the inner ring may be further provided. In this case, it is possible to further prevent foreign matter from entering the bearing without increasing the seal torque.

An adsorption preventing means for preventing the seal member from adsorbing to the inner ring may be provided on the seal member. The adsorption preventing means is, for example, a ventilation slit provided at the tip of the seal member.
When a contact-type seal member is provided, the seal member may be attracted to the inner ring and torque may increase due to a decrease in bearing internal pressure. In the present invention, at least the tip portion of the seal lip portion is made of a high wear material. However, until the seal member is worn, an adsorbing action is produced in the same manner as a general contact seal. By providing the suction prevention means such as the slit, the suction until the seal member is worn is prevented, and an increase in torque is avoided.

Any of the rolling bearings of the present invention may be used for an idler pulley for a timing belt of an automobile.
Any of the rolling bearings of the present invention may be used for a tensioner pulley for a dimming belt of an automobile.
In these cases, it is possible to reduce the loss of the timing belt system and to reduce the fuel consumption of the automobile.

  A rolling bearing according to the present invention is a rolling bearing which is incorporated in a pulley used under oil lubrication and rotatably supports the pulley, and includes a plurality of rolling elements interposed between inner and outer rings and raceway surfaces of the inner and outer rings. And a seal member that seals a bearing space formed between the inner and outer rings, wherein the seal member is a contact seal in which a base end is fixed to the outer ring and a seal lip portion is in contact with the inner ring. The seal lip portion includes a main body portion and a tip portion protruding from an inner peripheral edge of the main body portion and in contact with the inner ring, and at least the material of the tip portion is worn by using the bearing in a rotating state. This is a high-abrasion material that is non-contact or lightly contactable so that the contact pressure can be assumed to be zero.Therefore, a rolling bearing that rotatably supports a pulley used under oil lubrication is sealed. Achieving a reduction in the click, and it is possible to intrusion prevention foreign matter.

(A) is sectional drawing of the rolling bearing which concerns on 1st Embodiment of this invention, (B) is principal part sectional drawing which expands and shows the sealing member etc. of the rolling bearing. (A) is an enlarged cross-sectional view showing a state before wear when the seal lip portion of the seal member is in contact with the inner ring, and (B) is a view between the seal lip portion and the inner ring due to wear of the seal lip portion. It is an expanded sectional view which shows the state in which the optimal micro clearance gap was formed. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is an expanded sectional view of the principal part of the rolling bearing which concerns on other embodiment of this invention. It is a figure which shows schematically the belt layout of the timing belt which concerns on embodiment of this invention. It is sectional drawing which shows the example of the pulley for the timing belts. It is sectional drawing which shows the other example of the pulley for the timing belts. It is principal part sectional drawing which expands and shows the sealing member of the rolling bearing of a prior art example. It is an expanded sectional view of the principal part of the seal member.

A first embodiment of the present invention will be described with reference to FIGS.
The rolling bearing according to this embodiment is used for, for example, an idler pulley, a tensioner pulley, etc. of an automobile, and is particularly incorporated into various pulleys for timing belts used under oil lubrication to rotatably support the pulley. It is a rolling bearing.
As shown in FIG. 1A, in this rolling bearing, a plurality of rolling elements 3 are interposed between the raceway surfaces 1a and 2a of the inner and outer rings 1 and 2 at regular intervals in the circumferential direction. The inner and outer rings 1 and 2 and the rolling element 3 are made of, for example, high carbon chrome bearing steel such as SUJ2, martensitic stainless steel, or the like. However, it is not limited to these steels. This rolling bearing has a cage 4 that holds the plurality of rolling elements 3, and both ends of an annular bearing space formed between the inner and outer rings 1 and 2 are sealed with seal members 5, respectively. Grease is initially sealed in the bearing. The rolling bearing of this example is a deep groove ball bearing in which the rolling elements 3 are balls, and is an inner ring rotating type in which the inner ring 1 is a rotating ring and the outer ring 2 is a fixed ring. However, it is also possible to apply an angular ball bearing as a rolling bearing. It is also possible to use an outer ring rotating type in which the inner ring 1 is a fixed ring and the outer ring 2 is a rotating ring.

  The cage 4 is formed by combining two annular holding plates having hemispherical bulging portions arranged at predetermined intervals along the circumferential direction. Each annular holding plate is, for example, a cold-worked steel strip press product. Each annular holding plate has a hemispherical bulging portion disposed along the circumferential direction and a flat portion between adjacent hemispherical bulging portions. In a state where these annular holding plates are combined, the flat portions are overlapped, and the flat portions are connected via a fixing tool such as a rivet. However, the fixing tool is omitted, a claw-like engaging part is provided on one flat part, an engaged part is provided on the other flat part, and the flat part is connected by engaging the engaging part with the engaged part. You may let them. By connecting the flat portions, the hemispherical bulge portions face each other to form a ring-shaped pocket Pt.

The seal member 5 will be described.
As shown in FIG. 1B, a seal mounting groove 2 b for fitting and fixing the seal member 5 is formed on the inner peripheral surface of the outer ring 2. A seal lip portion, which will be described later, comes into contact with the outer diameter surface 1b of the inner ring 1 in the radial direction.
The seal member 5 includes an annular cored bar 6 and an elastic member 7 that is integrally fixed to the cored bar 6. The entire seal member 5 is formed, for example, by vulcanization molding of a rubber material, and the core metal 6 is bonded to the elastic member 7 during the vulcanization molding.

  The metal core 6 has a cylindrical portion 8, a standing plate portion 9, and an inclined portion 10 sequentially from the outer diameter side. The upright plate portion 9 is disposed substantially parallel to the end surface on the axially inner side of the bearing from the end surfaces of the inner and outer rings 1 and 2. The cylindrical portion 8 is connected to the base end of the standing plate portion 9, and the standing plate portion 9 and the cylindrical portion 8 form an L-shaped cross section. The elastic member outer peripheral portion 11 of the elastic member 7 provided mainly on the outer peripheral surface of the cylindrical portion 8 is fitted and fixed to the seal mounting groove 2 b of the outer ring 2. An inclined portion 10 that is slightly inclined inward in the axial direction as it goes toward the inner diameter side is connected to the inner peripheral end of the upright plate portion 9.

The elastic member 7 mainly has an elastic member outer peripheral portion 11, a cover portion 12, an inclined cover portion 13, and an elastic member inner peripheral portion 14.
The outer surface of the upright plate portion 9 in the cored bar 6 is covered with a uniform thin-walled cover portion 12. The inclined portion 10 is provided with an inclined cover portion 13 that is thicker than the cover portion 12. The inclined cover portion 13 covers the inner and outer surfaces of the inclined portion 10.
The inner surface of the inclined covering portion 13 is slightly inclined inward in the axial direction as it goes toward the inner diameter side. Therefore, the inner surface portion 13a constituting the inner surface of the inclined covering portion 13 has a uniform axial thickness along the radial direction. In addition, the outer surface of the inclined covering portion 13 is connected to the covering portion 12 in the same plane without a step. Therefore, the outer surface portion 13b constituting the outer surface of the inclined covering portion 13 is formed so that the axial thickness gradually increases toward the inner diameter side. The inner surface and outer surface portions 13a and 13b can increase the rigidity of the inclined cover portion 13 as a whole.

As shown in FIGS. 1B and 2A, an elastic member inner peripheral portion 14 is connected to the inner peripheral edge of the inclined covering portion 13 of the elastic member 7. The elastic member inner peripheral portion 14 extends to the inner diameter side of the inner peripheral edge of the inclined portion 10 in the cored bar 6.
The portion above the two-dot chain line in FIG. 2A and below the inclined cover portion 13 is the outer peripheral portion 14a of the elastic member inner peripheral portion 14, and the inner peripheral portion of the elastic member inner peripheral portion 14, that is, A portion below the two-dot chain line in FIG. 1A, 1B, and 2A, the tip portion 15b of the seal lip portion 15 represents a natural state. In the initial state before actual bearing operation, the tip portion 15b is not taken into the inner ring 1, and the outer diameter surface of the inner ring 1 with the distal end portion 15b of the seal lip portion 15 elastically deformed, as shown in the dot-dash line circle on the right side of FIG. It is in pressure contact with 1b.

  In the elastic member 7, the outer peripheral portion 14 a of the elastic member inner peripheral portion 14 is a portion that integrally connects the inclined covering portion 13 and the seal lip portion 15. The outer surface of the outer peripheral portion 14a is inclined inward in the axial direction toward the inner diameter side. The inner surface of the outer peripheral portion 14 a is connected to the inner peripheral edge of the inner surface of the inner surface portion 13 a in the inclined cover portion 13, and is connected to the inner surface of the seal lip portion 15 on the same surface without a step so as to be flat. In this example, the radial height H 1 of the outer peripheral portion 14 a of the elastic member inner peripheral portion 14 is shorter than the radial height H 2 of the seal lip portion 15. With the shape of the outer peripheral portion 14a and the inclined cover portion 13 described above, the rigidity of the radially inner peripheral portion of the seal member 5 can be reliably increased.

The seal member 5 is a contact seal in which the seal lip portion 15 is in contact with the outer diameter surface 1 b of the inner ring 1. In this example, the initial contact force of the seal lip portion 15 with respect to the inner ring 1 is defined as 11 N or more as will be described later.
The seal lip portion 15 has a main body portion 15a and the tip portion 15b. Among these, the tip portion 15b is provided to protrude from the inner surface side edge of the inner peripheral edge of the main body portion 15a toward the inner diameter side. In other words, the distal end portion 15b is protruded from the inner surface side edge, which is a part of the axial thickness at the inner peripheral edge of the main body portion 15a, to the inner diameter side, and in this example, the radial direction relative to the outer diameter surface 1b of the inner ring 1 The shape is in contact with. The axial thickness of the seal lip portion 15 is formed thinner than the axial thickness of the outer peripheral portion 14a, and the axial thickness of the tip portion 15b is formed thinner than the axial thickness of the main body portion 15a. Thereby, the contact force from the inner ring 1 can be concentrated and applied to the tip portion 15 b of the seal lip portion 15. Further, the radial height H of the elastic member inner peripheral portion 14 is set to be equal to or less than the axial thickness t1 of the main body portion 15a of the seal lip portion 15.

  The material of at least the tip portion 15b of the seal lip portion 15 is a high-abrasion material that is lightly contacted so that it can be worn out of contact or contact pressure can be regarded as zero when the bearing is used in a rotating state. is there. The high wear material may be provided only on the tip portion 15b of the seal lip portion 15 or across the tip portion 15b and the main body portion 15a. Further, a high wear material may be provided over the outer peripheral portion 14 a of the seal lip portion 15 and the elastic member inner peripheral portion 14. This high wear material is selected from a specific type depending on the compatibility with the bearing operating temperature and the lubricating oil. The high wear material includes, for example, a high wear rubber material. For example, a resin material, a solid lubricant, a non-woven fabric, a mild steel, or the like may be applied as another material constituting the high wear material.

  FIG. 2A is an enlarged cross-sectional view of the main part in a state where the seal lip portion is in contact with the outer diameter surface of the inner ring, and FIG. 2B is a view in which the tip portion of the seal lip portion is worn by using the bearing in a rotating state. It is an expanded sectional view of the important section of a state. For example, when the bearing is used for 1 hour to several hours, which is about the time of running-in in a rotating state, the tip portion 15 b of the seal lip portion 15 of the seal member 5 is worn. That is, the seal member 5 changes from the contact state of FIG. 2A to a non-contact state in which the optimum labyrinth clearance of FIG.

The seal mold for molding the seal member 5 has an upper mold and a lower mold. A cavity for molding the seal member 5 is formed in a state where the upper mold and the lower mold are combined. The seal mold is formed with a gate for injecting the material of the elastic member 7 into the cavity.
The tip portion 15b to which the high wear rubber material is applied and the other portion of the elastic member 7 to which the high wear rubber material is not applied are molded by the seal mold, for example, by two-color molding. That is, after the other portion of the elastic member 7 on the primary side is molded, the high wear rubber material is poured into the cavity of the tip portion 15b of the seal lip portion 15 on the secondary side, and the elastic member 7 is molded integrally. In this way, the tip end portion 15b of the seal lip portion 15 on the secondary side in the same seal mold is molded integrally with the other portions.

  According to the rolling bearing described above, since the material of the tip end portion 15b of the seal lip portion 15 is a high wear material as described above for the rolling bearing incorporated in the pulley used under oil lubrication, it is a contact type at the initial stage of operation. Thus, the seal member 5 becomes a non-contact or light contact type seal member 5 at an early stage after operation due to wear. Further, due to the wear of the seal member 5, a minute optimum labyrinth gap is formed between the seal lip portion 15 and the inner ring 1 as an optimum non-contact seal gap or a light contact seal gap. By forming the optimum labyrinth gap, the following effects can be obtained.

(1). Seal torque is reduced.
(2). The self-heating of the bearing is lower than the conventional product.
(3). By lowering the self-heating of the bearing, it is possible to select an oil having a lower viscosity than the conventional oil.
(4). Loss of the timing belt system can be reduced by reducing the sealing torque and selecting low viscosity oil.
(5). The labyrinth clearance allows oil to pass into the bearing, but it can prevent the entry of foreign matter with a large particle size that affects the bearing life.

  The tip end portion 15b of the seal lip portion 15 is provided so as to protrude from the inner surface side edge of the inner peripheral edge of the main body portion 15a toward the inner diameter side. That is, the distal end portion 15b is projected from the inner surface side edge, which is a part of the axial thickness of the inner peripheral edge of the main body portion 15a, toward the inner diameter side, and has a shape that contacts the outer diameter surface 1b of the inner ring 1 in the radial direction. . In this case, the rigidity of the seal member 5 can be increased as compared with the case where the tip end portion 15b of the seal lip portion 15 is provided on the outer side in the axial direction or in the middle of the main body portion 15a. As a result, the seal lip portion 15 does not easily warp outward in the axial direction, and a strong contact force can be applied to the seal lip portion 15.

  Moreover, since the radial height H of the elastic member inner peripheral portion 14 of the seal member 5 is set to be equal to or less than the axial thickness t1 of the main body portion 15a of the seal lip portion 15, the elastic member 7 has a low rigidity inside the elastic member. The height in the radial direction of the peripheral portion 14 can be made shorter than the structure of FIG. Therefore, the rigidity of the seal member 5 can be increased as compared with the structure of FIG. 15, and a strong contact force can be applied to the seal lip portion 15. Therefore, the tip portion 15b of the seal lip portion 15 can be more reliably worn.

In the case of the configuration shown in FIGS. 1 and 2, the seal contact surface where the tip portion 15b of the seal lip portion 15 is in contact with the inner ring 1 is the outer diameter surface 1b of the inner ring 1. Therefore, the inner ring seal groove shown in FIG. Compared to the configuration of the surface, the overall length of the seal member 5 in the radial direction can be shortened. Therefore, the rigidity of the seal member 5 can be increased compared with the seal member corresponding to the inner ring seal groove, and a strong contact force can be applied to the seal lip portion 15 by the operation of the bearing.
As described above, in the seal member 5 according to the present embodiment, (a) the tip portion 15b of the seal lip portion 15 is provided so as to protrude from the inner surface side edge of the inner peripheral edge of the main body portion 15a to the inner diameter side, and (b) elasticity. Since the radial height H of the member inner peripheral portion 14 is set to be equal to or less than the axial thickness t1 of the main body portion 15a of the seal lip portion 15, and (c). The seal contact surface is the outer diameter surface 1b of the inner ring 1, The rigidity of the member 5 can be significantly increased compared to the conventional one, and a strong contact force can be applied to the seal lip portion 15. Therefore, the front end portion 15b of the seal lip portion 15 can be worn early after operation. That is, the effects (1) to (5) can be obtained early after the operation.

  Since the seal lip portion 15 of the seal member 5 has a shape that comes into contact with the inner ring 1 in the radial direction, the seal lip portion 15 comes into contact with the inner ring 1 in the radial direction and wears to a non-contact state or a light contact state. After that, even if the bearing space becomes negative pressure, the seal lip portion 15 is not attracted or reduced.

Here, the seal contact force will be described.
In this example, the initial contact force (also referred to as “seal contact force”) of the seal lip 15 to the inner ring 1 is defined as 11 N or more. The contact force, which is the pressing force of the seal lip portion 15 against the inner ring 1, includes the material of the seal member 5, the shape of the elastic member 7, the core metal shape, and the tightening allowance between the tip portion 15 b of the seal lip portion 15 and the inner ring 1. It depends on factors such as. The contact force fluctuates due to various factors as described above. However, if a certain amount of contact force is applied to the seal lip portion 15, the seal lip portion 15 can be worn at an early stage.

After the start of operation, no contact is made within 60 minutes under oil bath or absolutely dry conditions. As an example of operating conditions, for example, a rolling bearing of bearing model number: 6207 (JIS standard), rotating speed 4000 rpm, bearing temperature: 30 ° C., rotating torque is about 0.075 N · m. It becomes non-contact within 60 minutes.
In the above example, the rolling bearing having the bearing model number 6207 is used for operation, but it is not limited to the bearing model number. In the present invention, the seal contact force is used as a criterion so that evaluation can be performed even if the bearing model number, that is, the inner diameter, outer diameter, and width dimension of the bearing are different. Note that the rotational torque of the bearing is measured, and the seal contact force is obtained by calculation based on the measured rotational torque.

Timing for evaluating ○ in Table 1 below: The rotational torque is visually confirmed with a testing machine that can always measure the rotational torque of the bearing. Evaluation ends when 60 minutes have elapsed after the start of operation or when the rotational torque is equivalent to that of a product without a seal.
Regarding the judgment criteria of ○ × in Table 1 below: The judgment criteria are whether the bearing torque is the same level as that of the bearing without seal within 60 minutes after the start of operation. If the bearing torque is the same level as that of the unsealed bearing, it is marked as ◯.

The test results shown in Table 1 below were obtained for the relationship between the seal contact force and the wear of the seal lip 15 by the above test.

It was found that the tip portion 15b of the seal lip portion 15 was worn early after operation by setting the contact force of the seal lip portion 15 to 11 N or more regardless of the bearing size.
Furthermore, the surface roughness of the seal contact surface in the inner ring 1 may be Ra 1.0 μm or more. In this case, combined with the contact force of the seal lip portion 15, the tip portion 15b of the seal lip portion 15 can be worn early after operation.

  Hereinafter, other embodiments of the present invention will be described. In the following description, the same reference numerals are given to the portions corresponding to the matters described in the preceding forms in each embodiment, and the overlapping description is omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in the preceding section. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

  As shown in FIG. 3, a seal groove 16 may be formed in the inner ring outer diameter surface 1 b, and the tip end portion 15 b of the seal lip portion 15 may be brought into radial contact with the groove bottom surface 16 a of the seal groove 16. According to the configuration of FIG. 3, the rigidity becomes lower than that of FIG. 1 due to the fact that the total length of the seal member is longer, but the tip end portion 15 b of the seal lip portion 15 is placed inward of the main body portion 15 a of the seal lip portion 15 in the axial direction. Since the seal member 5 is provided, the rigidity of the seal member 5 is increased as compared with the conventional one. As a result, the seal lip portion 15 does not easily warp outward in the axial direction, and a strong contact force can be applied to the seal lip portion 15.

  In the configuration of FIG. 4, the radial height H of the inner circumferential portion 14 of the elastic member is larger than the axial thickness t1 of the main body portion 15 a of the seal lip portion 15. Since 15b is provided on the inner side in the axial direction of the main body portion 15a, the rigidity of the seal member 5 is increased compared to the conventional one, and thereby the seal lip portion 15 is less likely to warp outward in the axial direction, and a strong contact force is applied to the seal lip portion 15. Can give.

  As shown in FIG. 5, a non-contact seal lip portion 17 that does not contact the inner ring 1 may be provided as a part of the elastic member 7. The non-contact seal lip portion 17 extends inward in the axial direction from the vicinity of the inner peripheral edge of the inclined portion 10 of the core metal 6 in the inner peripheral portion 14 of the elastic member, and extends toward the inner side in the axial direction. Inclined and protrudes to the vicinity of the corner between the side surface 16b and the inner ring outer diameter surface 1b. A plurality of the non-contact seal lip portions 17 may be provided at different positions in the radial direction of the elastic member 7. In this case, it is possible to further prevent foreign matter from entering the bearing without increasing the seal torque. Further, since the non-contact seal lip portion 17 is inclined as described above, the lubricant adhering to the inner surface of the seal member 5 is passed through the inner ring outer diameter surface 1b to the inner ring raceway surface 1a (FIG. 1 (A)). It becomes possible to make it contribute to lubrication. Other effects similar to those of FIG.

  In the configuration of FIG. 6, the tip end portion 15b of the seal lip portion 15 is provided on the outer side in the axial direction of the main body portion 15a, but the contact force of the seal lip portion 15 with respect to the inner ring 1 is 11N or more. By setting the contact force of the seal lip 15 to 11 N or more, the seal torque is reduced at an early stage, and the self-temperature rise of the bearing is quickly reduced with respect to a conventional product having the contact force of less than 11 N. By reducing the self-temperature rise of the bearing at an early stage, it is possible to select oil having a lower viscosity than conventional oil. When this bearing is used in a timing belt system used under oil lubrication, loss of the entire timing belt system can be expected. Since a so-called labyrinth gap is formed between the seal lip portion 15 and the inner ring 1, it is possible to prevent entry of a foreign substance having a large particle diameter that affects the bearing life at an early stage.

  As shown in FIG. 7, the tip end portion 15 b of the seal lip portion 15 may be shaped to contact the inner ring 1 in the axial direction. The tip portion 15b is provided to protrude inward in the axial direction from the inner peripheral surface portion on the inner diameter side of the main body portion 15a. The tip portion 15b comes into contact with the inner surface 16b of the seal groove 16 with a contact force of 11N or more.

It is good also as a structure shown in FIG. 8, FIG. 9 which provided the non-contact seal lip | rip parts 17 and 17A in the structure of FIG. 6, FIG. 7, respectively. The non-contact seal lip portions 17 and 17A can further prevent foreign matter from entering the bearing without increasing the seal torque.
In the configuration of FIG. 8, since the non-contact seal lip portion 17 is inclined as described above with reference to FIG. 5, the lubricant adhering to the inner surface of the seal member 5 is passed through the inner ring outer diameter surface 1b through the inner ring raceway surface 1a. It becomes possible to make it contribute to lubrication.
9, the lubricant can be held in the annular space A1 surrounded by the tip portion 15b of the seal lip portion 15, the non-contact seal lip portion 17A, and the inner ring seal groove 16. The lubricant retained in the annular space A1 can further prevent foreign matter from entering the bearing. The lubricant in these cases may be a part of the grease previously sealed in the bearing, or may be oil lubricated oil used in the timing belt system.

  As shown in FIGS. 10 and 11, a slit SL as an adsorption preventing means may be provided at the tip portion 15 b of the seal lip portion 15. The slit SL is provided at one place or a plurality of places in the circumferential direction. With the tip portion 15b of the seal lip portion 15 in contact with the seal contact surface of the inner ring 1, the bearing space is vented in the inner and outer directions. It is possible to prevent the seal member 5 from being adsorbed to the inner ring 1 by the reduction of the internal pressure accompanying the operation of the bearing by the ventilation from the slit SL.

  FIG. 12 is a diagram schematically showing a belt layout of a timing belt that drives a camshaft of an automobile. As shown in the figure, an endless belt Bt is hung across the cam pulleys 18, 18, idler pulley 19, oil pump 20, crank pulley 21, and tensioner pulley 22. These pulleys are used under oil lubrication. The tensioner pulley 22 applies an appropriate tension to the belt Bt. The idler pulley 19 accurately guides the belt Bt.

The examples of FIGS. 13 and 14 are cross-sectional views of idler pulleys. In the example of FIG. 13, the pulley portion 23 is formed integrally with the outer ring 2 on the outer circumferential surface of the outer ring, and is provided wider than both side surfaces of the outer ring. In this case, since the pulley can be manufactured by cutting the outer ring material or the like, the rigidity of the pulley can be increased, and the rotational accuracy and dimensional accuracy can be easily increased. In this rolling bearing, a so-called crown-shaped cage 4 is applied in place of the corrugated cage 4 combined with an annular retaining plate. In the crown-shaped cage 4, pockets Pt for holding the rolling elements 3 are formed at regular intervals in the circumferential direction on one axial side surface of the annular body.
In the example of FIG. 14, the pulley portion 23 is formed separately from the outer ring 2, and the outer ring outer peripheral surface is incorporated in the axial intermediate portion 23 a on the inner peripheral surface of the pulley portion 23. In the case of FIG. 14, a pulley made of a resin material can be used, so that mass production can be achieved and the cost can be reduced as compared with that of FIG. In addition, the weight of the components can be reduced.

  13 and 14, in the rolling bearing incorporated in the pulley, the material of the tip portion 15b (FIG. 1B) of the seal lip portion 15 is the high wear material as described above. The contact type seal member 5 becomes a non-contact or light contact type seal member 5 at an early stage after operation due to wear. Thereby, a minute optimum labyrinth gap is formed between the seal lip portion 15 and the inner ring 1. In the examples of FIGS. 13 and 14, a so-called back flat pulley for guiding the flat portion of the belt is shown as the pulley, but a pulley with a front groove for guiding the groove side of the belt may be used.

Also for the bearing incorporated in the tensioner pulley 22 of FIG. 12, the aforementioned seal member 5 is provided, and the seal member 5 becomes a non-contact or light contact type seal member 5 at an early stage after operation due to wear.
For example, the above-described seal member 5 may be provided for a bearing incorporated in an idler pulley for an accessory belt that drives an electrical component of an automobile or an accessory.
Instead of forming a seal member by vulcanization molding of a rubber material, a seal member may be formed by injection molding of a resin material. The rolling bearing according to each embodiment may be a full ball bearing without a cage.

DESCRIPTION OF SYMBOLS 1 ... Inner ring 1b ... Outer diameter surface 2 ... Outer ring 1a, 2a ... Raceway surface 3 ... Rolling element 5 ... Seal member 6 ... Core metal 7 ... Elastic member 14 ... Elastic member inner peripheral part 15 ... Seal lip part 15a ... Main body part 15b ... tip portions 17 and 17A ... non-contact seal lip 19 ... idler pulley 22 ... tensioner pulley SL ... slit

Claims (15)

A rolling bearing that is incorporated in a pulley used under oil lubrication and rotatably supports the pulley, and includes an inner and outer ring, a plurality of rolling elements interposed between raceway surfaces of the inner and outer rings, and the inner and outer rings. In a rolling bearing provided with a seal member for sealing a formed bearing space,
The seal member is a contact seal having a base end fixed to the outer ring and a seal lip portion in contact with the inner ring, and the seal lip portion protrudes from an inner peripheral edge of the main body portion and contacts the inner ring. And at least the material of the tip portion is a high wear material that wears out of contact with the bearing when it is used in a rotating state or is lightly contacted so that the contact pressure can be regarded as zero. Characteristic rolling bearing.   The rolling bearing according to claim 1, wherein the high wear material is a rubber material or a resin material.   3. The rolling bearing according to claim 2, wherein the high wear material is a rubber material, and the seal member is formed by vulcanization molding of the rubber material.   The rolling bearing according to claim 2, wherein the high wear material is a resin material, and the seal member is formed by injection molding the resin material.   The rolling bearing according to any one of claims 1 to 4, wherein a contact force of the seal lip portion with respect to the inner ring is 11N or more.   The rolling bearing according to any one of claims 1 to 5, wherein a surface roughness of a seal contact surface in the inner ring is Ra 1.0 µm or more.   The rolling bearing according to any one of claims 1 to 6, wherein the seal lip portion of the seal member is in a shape in contact with the inner ring in a radial direction.   The rolling bearing according to claim 7, wherein a tip portion of the seal lip portion protrudes from an inner surface side edge of an inner peripheral edge of the main body portion and comes into contact with an inner ring.   The rolling bearing according to claim 7 or 8, wherein a seal contact surface where a tip portion of the seal lip portion is in contact with the inner ring is an outer diameter surface of the inner ring.   The rolling bearing according to any one of claims 1 to 6, wherein the seal lip portion of the seal member has a shape that contacts the inner ring in the axial direction.   11. The seal member according to claim 1, wherein the seal member includes an annular cored bar and an elastic member that covers the cored bar and is provided integrally with the cored bar. The elastic member includes an inner peripheral portion that extends to the inner diameter side from the inner peripheral edge, the inner peripheral portion of the inner peripheral portion of the elastic member is the seal lip portion, and the radial height of the inner peripheral portion of the elastic member is the seal lip. Rolling bearing with a thickness equal to or less than the axial thickness of the body part.   The rolling bearing according to any one of claims 1 to 11, further comprising a non-contact seal lip portion that extends from a main body portion of the seal lip portion and does not contact an inner ring.   The rolling bearing according to any one of claims 1 to 12, wherein an adsorption preventing means for preventing the seal member from adsorbing to an inner ring is provided on the seal member.   14. The rolling bearing according to claim 1, wherein the rolling bearing is used for an idler pulley for a timing belt of an automobile.   14. The rolling bearing according to claim 1, wherein the rolling bearing is used in a tensioner pulley for a timing belt of an automobile.

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