JP2015086940A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing which can reduce the leakage of a sealed lubricant even if an air flow exists in an axial direction.SOLUTION: This rolling bearing 10 comprises: an outer ring 20 in which an outer ring raceway face 22 is formed at an internal peripheral face; an inner ring 30 in which an inner ring raceway face 32 is formed at an external peripheral face; a plurality of balls 15 which are rollingly arranged between the outer ring raceway face 22 and the inner ring raceway face 32; a cage 40 for holding the plurality of balls 15; and a pair of seal members 50, 55 which seal a bearing space between the outer ring 20 and the inner ring 30, and are arranged at both sides of an axial direction. A lubricant is sealed into the bearing space, and an air flow exists in the axial direction. The rolling bearing 10 is sealed with the lubricant from an upstream side of the air flow, and the lubricant which is initially arranged at the upstream side of the air flow rather than an axial center of the balls 15 occupies 80% or larger of all the lubricants which are sealed into the bearing space.

Description

  The present invention relates to a rolling bearing in which a lubricant is enclosed.

  In rolling bearings, the races and rolling elements are lubricated by a lubricant such as grease enclosed in a bearing space sealed by a seal or the like. In order to prevent leakage of the lubricant from the opening and clearance of the seal, various techniques have been conventionally proposed (see, for example, Patent Document 1).

  FIG. 10 is a diagram for explaining a grease sealing position in Patent Document 1. In FIG. As shown in FIG. 10, Patent Document 1 discloses that the initial sealing position of grease is within the range on the outer diameter side of the pitch circle diameter PCD of the rolling elements 103 in the bearing space between the inner ring 101 and the outer ring 102, and the seal It is described that grease leakage is prevented by setting the gap far from the initial sealing position.

JP 2007-321882 A

  By the way, when there is an air flow in the axial direction in a rolling bearing in which grease is sealed in the bearing space, the grease sealed on the downstream side of the air flow is the clearance of the base oil that has exuded from the grease on the downstream side of the air flow (seal Directly between the rotating wheel and the rotating wheel, and there is a risk that the rolling elements and the raceway cannot be sufficiently lubricated. In addition, for the grease sealed on the upstream side of the airflow, after the base oil that has oozed out of the grease passes through the rolling elements and the raceway and is lubricated, it may be discharged from the clearance on the downstream side of the airflow. is there. Thus, when there is an air flow in the axial direction in a bearing in which grease is sealed in the bearing space, there is a possibility that the rolling elements and the races cannot be sufficiently lubricated.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a rolling bearing capable of reducing leakage of the enclosed lubricant even when there is an air flow in the axial direction.

The above object of the present invention can be achieved by the following constitution.
(1) An outer ring having an outer ring raceway surface formed on the inner peripheral surface, an inner ring having an outer ring raceway surface formed on the outer peripheral surface, and a rollable arrangement between the outer ring raceway surface and the inner ring raceway surface. A plurality of rolling elements, a cage for holding the plurality of rolling elements, and a pair of seal members disposed on both sides in the axial direction for sealing a bearing space between the outer ring and the inner ring. A rolling bearing that encloses a lubricant in the space and has an air flow in the axial direction,
Encapsulating the lubricant from the upstream side of the air flow;
The rolling bearing according to claim 1, wherein the lubricant initially disposed upstream of the center in the axial direction of the rolling element is 80% or more of the total lubricant enclosed in the bearing space.
(2) 50% or more of the total lubricant to be sealed in the bearing space is initially disposed on an axial end surface of the cage located on the upstream side of the air flow. Rolling bearings.
(3) An axial end portion of the cage located on the upstream side of the air flow protrudes radially inward and is in close proximity to the outer peripheral surface of the inner ring (1) or (2) ) Rolling bearing according to
(4) In any one of (1) to (3), a plurality of recesses for holding the lubricant is provided on an axial end surface of the cage located on the upstream side of the air flow. Rolling bearings.

  According to the present invention, even when there is an air flow in the axial direction in a rolling bearing in which a lubricant is sealed in the bearing space, leakage of the lubricant can be reduced and the lubrication performance can be improved.

It is sectional drawing of the angular contact ball bearing which has the holder | retainer of a both-ends structure concerning 1st Embodiment of this invention. 1 is a cross-sectional view of an angular ball bearing having a cantilevered cage according to a first embodiment of the present invention. It is sectional drawing of the angular ball bearing which has the holder | retainer of a both-ends structure concerning the modification of 1st Embodiment of this invention. It is sectional drawing of the angular ball bearing which has a cantilevered retainer concerning the modification of 1st Embodiment of this invention. It is sectional drawing of the angular ball bearing concerning 2nd Embodiment of this invention. (A) is the figure which looked at the retainer of the rolling bearing concerning 3rd Embodiment of this invention from the radial direction outer side, (b) is XX sectional drawing of (a). It is a figure similar to FIG.6 (b) of the cage of the rolling bearing concerning the 1st modification of 3rd Embodiment of this invention. It is a figure similar to FIG.6 (b) of the cage | basket of the rolling bearing concerning the 2nd modification of 3rd Embodiment of this invention. It is the figure which looked at the cage of the rolling bearing concerning 4th Embodiment of this invention from the radial inside. It is a figure for demonstrating the conventional grease enclosure method.

(First embodiment)
Hereinafter, a rolling bearing according to a first embodiment of the present invention will be described with reference to FIG. The rolling bearing 10 shown in FIG. 1 is configured to roll between an outer ring 20 having an outer ring raceway surface 22 on an inner circumferential surface, an inner ring 30 having an inner ring raceway surface 32 on an outer circumferential surface, and the outer ring raceway surface 22 and the inner ring raceway surface 32. A plurality of balls 15 that are freely movable in the circumferential direction, a cage 40 that holds the balls 15, and a space between the outer ring 20 and the inner ring 30 (hereinafter also referred to as a bearing space) on both sides in the axial direction. And a pair of seal members 50 and 55 arranged. The rolling bearing 10 is an angular ball bearing, and a counter bore 34 is formed on one side of the inner ring 30 in the axial direction.

  The outer ring 20 and the inner ring 30 are preferably formed from bearing steel such as SUJ2, particularly bearing steel that has been subjected to carburizing or carbonitriding, but is not limited thereto. The outer ring 20 and the inner ring 30 may be formed of a material obtained by performing carburization or carbonitriding on alloy steel obtained by adding alloy elements such as silicon, manganese, chromium, and molybdenum to medium carbon steel as necessary. In particular, when the bearing is used under high-speed and high-temperature conditions, the outer ring 20 and the inner ring 30 are obtained by carburizing or carbonitriding the alloy steel with an increased amount of silicon among the above alloy steels. Preferably it is formed. The balls 15 are made of bearing steel or ceramic.

  The cage 40 holds the balls 15 one by one in a plurality of pockets formed by a pair of annular portions 41 and 42 and a plurality of column portions 43 that connect the pair of annular portions 41 and 42 in the axial direction. This is a so-called double-sided cage. The retainer 40 is an outer ring guide type retainer whose outer peripheral surface is guided by the shoulder portion 26 of the outer ring 20, and can be formed from a resin material that satisfies necessary strength, heat resistance, and the like. The resin material for forming the cage 40 is not particularly limited, but synthetic resins such as nylon 46, nylon 66, polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), polyetheretherketone (PEEK) are preferable. In addition, a resin composition containing about 10 to 40% by mass of a reinforcing material such as glass fiber (GF) or carbon fiber (CF) as a reinforcing fiber in the resin has high toughness and mechanical strength at high temperatures. This is particularly preferable.

  The seal member 50 includes a metal core 51 in which a metal thin plate is formed in a substantially annular shape, and an elastic portion 53 formed of rubber so as to cover the metal core 51, and the seal member 55 is a metal plate in a substantially circular shape. An annular cored bar 56 and an elastic part 58 formed of rubber so as to cover the cored bar 56 are provided. The seal member 50 is fixed to one end portion in the axial direction of the inner peripheral surface of the outer ring 20 by the outer peripheral portion 52, and the seal member 55 is fixed to the other end portion in the axial direction of the inner peripheral surface of the outer ring 20 by the outer peripheral portion 57. It is fixed to. The seal lip 54 serving as the inner peripheral edge of the seal member 50 (elastic portion 53) extends to the vicinity of the outer peripheral surface of the inner ring 30 so as to face the outer peripheral surface of the inner ring 30, and the seal member 55 (elastic portion) 58), the seal lip 59 serving as the inner peripheral edge extends to the vicinity of the outer peripheral surface of the inner ring 30 so as to face the outer peripheral surface of the inner ring 30. Thus, the seal members 50 and 55 are non-contact seal members with respect to the outer peripheral surface of the inner ring 30.

  By the way, in the rolling bearing 10 which is an angular ball bearing, when the inner ring 30 rotates, a differential pressure is generated in the bearing space by the counter bore 34 of the inner ring 30. Due to such a pump effect, an air flow in the direction of arrow A is generated in the bearing space of the rolling bearing 10.

  As described above, in this embodiment, the details of the initial encapsulation of grease in the bearing space are defined for the rolling bearing in which an axial air flow is generated in the bearing space. Here, initial filling of the grease into the bearing space is performed not from the air flow downstream side but from the air flow upstream side. In the present embodiment, as shown in FIG. 1, grease (hereinafter also referred to as grease G1) is applied to the axial end surface of the retainer 40 located on the upstream side of the air flow, that is, the axial end surface of the annular portion 41. Encapsulate. The amount of grease G1 sealed is set to be 50% or more of the total amount of grease sealed in the bearing space. Thus, the grease G1 disposed on the end surface in the axial direction of the retainer 40 is less susceptible to the air flow, and the movement of the grease G1 to the downstream side of the air flow is blocked by the annular portion 41. As a result, the grease can be retained on the upstream side of the air flow, so that the amount of grease leaking from the clearance between the seal member 55 located on the downstream side of the air flow and the inner ring 30 can be reduced, and the lubrication performance can be improved for a long time. It is possible to improve the life of the bearing by preventing the seizure of the bearing.

  Further, as described above, since the retainer 40 is an outer ring guide retainer, the clearance between the retainer 40 and the outer ring 20 is small, so that the movement of the grease G1 can be further suppressed.

  Further, in the present embodiment, grease (hereinafter, referred to as “grease”) is provided between the inner peripheral surface of the retainer 40 and the counter bore 34 of the inner ring 30 and at a position located upstream of the axial center of the ball 15 in the air flow direction. (Also referred to as grease G2). The sum of the amount of grease G2 and the amount of grease G1 described above is 80% or more of the total amount of grease enclosed in the bearing space. Thereby, the lubricity at the initial stage of the bearing operation can be ensured and the lubrication performance can be further improved.

  The rolling bearing according to the present embodiment is not limited to the angular ball bearing having the above-described double-supported cage 40, and may be another type of rolling bearing. For example, as shown in FIG. 2, a plurality of annular portions 61 arranged on one side in the axial direction and a plurality of column portions 63 extending from the annular portion 61 in the circumferential direction at a predetermined interval in the axial direction. It may be a rolling bearing 10 ′ having a cage (crown type cage) 60 having a pocket. The retainer 60 is a so-called cantilever retainer, and is guided by the balls 15 that are rolling elements in a state where the clearance between the annular portion 61 and the outer ring 20 is reduced.

(Modification)
Hereinafter, the rolling bearing concerning the modification of 1st Embodiment of this invention is demonstrated using FIG. A rolling bearing 10A shown in FIG. 3 has the same configuration as that of the rolling bearing 10 shown in FIG. 1, but in addition to the greases G1 and G2 encapsulated in the first embodiment, the rolling bearing 10A is more air-tight than the axial center of the ball 15. Grease (hereinafter also referred to as grease G <b> 3) is sealed on the downstream side, more specifically, on the axial end surface of the annular portion 42 located on the downstream side of the air flow. In this way, by enclosing the grease not only on the upstream side of the air flow but also on the downstream side, the amount of the grease is increased and the lubrication performance is improved, so the life of the bearing can be improved.

  Note that the rolling bearing according to this modification is not limited to the rolling bearing 10A as shown in FIG. 3, but may be a rolling bearing 10A ′ having a cantilevered retainer 60 as shown in FIG. In this case, the grease G3 may be disposed on the inner circumferential surface of the outer ring 20 and the inner circumferential surface of the inner ring 30 as shown in FIG.

(Second Embodiment)
Hereinafter, the rolling bearing which concerns on 2nd Embodiment of this invention is demonstrated using FIG. Parts having the same configuration as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. A rolling bearing 10B shown in FIG. 5 is an angular ball bearing in which a counter bore 34 is formed on an inner ring 30, and couples a pair of annular portions 71, 72 and the pair of annular portions 71, 72 in the axial direction. A double-supported cage 70 having a plurality of column portions 73 is provided.

  As shown in FIG. 5, the retainer 70 has a grease retaining portion 78 that protrudes radially inward from the axial end portion of the annular portion 71 located on the upstream side of the air flow. The inner peripheral surface of the grease retaining portion 78 is in close proximity to the counter bore 34 of the inner ring 30. Thus, even when an air flow is generated in the bearing space, the grease initially sealed on the upstream side of the air flow is kept on the upstream side as it is, and the seal member 55 and the inner ring 30 positioned on the downstream side of the air flow It is possible to greatly reduce the amount of grease leaking from the gap between the two. Thereby, since the lubrication performance of the bearing can be improved over a long period of time, seizure of the bearing can be prevented and the life of the bearing can be improved. Further, by providing the grease retaining portion 78, the axial end surface of the cage 70 in which the grease is initially sealed is expanded in the radial direction and the area is increased, so that more grease can be sealed. .

(Third embodiment)
Hereinafter, a rolling bearing cage according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 6A shows an outer ring guide formed by a pair of annular portions 81 and 82 and a plurality of column portions 83 that connect the pair of annular portions 81 and 82 in the axial direction, for example, used in an angular ball bearing. It is the figure which looked at the cage | basket 80 of the system from the radial direction outer side, FIG.6 (b) is XX sectional drawing of Fig.6 (a).

  The retainer 80 is opened in the middle in the radial direction of the axial end surface of the annular portion 81 located on the upstream side of the air flow, and is formed in the axial direction from the annular portion 81 to the midway portion of the column portion 83 in the axial direction. A recess 85 is provided. A plurality of holding recesses 85 are provided at predetermined intervals in the circumferential direction between pockets 84 adjacent in the circumferential direction. In order to secure a thickness between the holding recess 85 and the pocket 84, the holding recess 85 has a substantially triangular shape with two sides being curved along the contour of the pocket 84 when viewed from the radial direction. . As shown in FIG. 6B, the holding recess 85 has a rectangular cross section in the axial direction.

  Thus, in the retainer 80, a plurality of retaining recesses 85 are provided on the axial end surface located on the upstream side of the air flow. In this embodiment, since grease can be enclosed in the holding recess 85, it is possible to reduce grease movement to the air flow downstream side and grease leakage from the air flow downstream side. Further, since the holding recess 85 is not opened on the outer peripheral surface of the cage 80, the cage 80 is stably guided by the outer ring on the outer peripheral surface.

(First modification)
FIG. 7: shows sectional drawing of the holder | retainer of the rolling bearing concerning the 1st modification of 3rd Embodiment of this invention. As shown in FIG. 7, the cage 80 ′ opens to the axial end surface of the annular portion 81 located on the upstream side of the air flow, and extends in the axial direction from the annular portion 81 to the axially intermediate portion of the column portion 83. A holding recess 86 is formed. Unlike the holding recess 85 of the cage 80 shown in FIGS. 6 (a) and 6 (b), the holding recess 86 is also opened on the inner peripheral surface of the cage 80 ′. As described above, since the holding recess 86 is also opened on the inner peripheral side of the cage 80 ′, more grease can be enclosed and held. Further, since the holding recess 86 is not opened on the outer peripheral surface of the cage 80 ′, the cage 80 ′ is stably guided by the outer ring on the outer circumferential surface.

(Second modification)
FIG. 8: shows sectional drawing of the holder | retainer of the rolling bearing concerning the 2nd modification of 3rd Embodiment of this invention. The cage 80 '' shown in FIG. 8 is formed in the axial direction from the annular part 81 to the axially intermediate part of the column part 83, opening at the axial end surface of the annular part 81 located on the upstream side of the air flow. Holding recess 87. The radial depth of the holding recess 87 is formed to be shallower than the holding recess 86 of the cage 80 ′ shown in FIG. As described above, since the plurality of holding recesses 87 are provided, it is possible to enclose and hold grease in the holding recesses 87, so that the grease moves to the downstream side of the air flow and the grease leaks from the downstream side of the air flow. Can be reduced.

  Further, the annular portion 81 of the retainer 80 ″ further includes a scraping portion 89 that opens to the axial end surface of the annular portion 81 and opens to the outer peripheral surface of the retainer 80 ″. The shape of the scraped portion 89 is a substantially triangular shape having two sides that are curved along the outline of the pocket 84 when viewed from the radial direction. When the cage 80 ″ rotates, the grease that adheres to the inner peripheral surface of the outer ring is returned to the upstream side of the air flow by the two curved surfaces of the scraping portion 89, further reducing the leakage of grease from the downstream side of the air flow. can do. The axial dimension of the scraped portion 89 is a dimension that does not reach the pocket 84, that is, a dimension that is shorter in the axial direction than the holding recess 87, so that the scraped portion 89 and the outer ring raceway surface do not communicate with each other. As a result, the area of the cage guide surface by the outer ring can be secured, and the grease can be prevented from flowing out to the outer ring raceway surface when the bearing is not rotating.

(Fourth embodiment)
Hereinafter, a cage for a rolling bearing according to a fourth embodiment of the present invention will be described with reference to FIG. Parts having the same configuration as in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the lubricant encapsulating method of the fourth embodiment, as shown in FIG. 9, a pair of annular portions 91 and 92 and a plurality of column portions 93 that connect the pair of annular portions 91 and 92 in the axial direction are formed. The retained cage 90 is used. FIG. 9 is a view of the cage 90 as viewed from the inside in the radial direction.

  The retainer 90 has a shape that combines the retainer 70 shown in FIG. 5 and the retainer 80 ′ shown in FIG. 7. That is, as shown in FIG. 9, the retainer 90 has a grease retaining portion 98 that protrudes radially inward from the axial end portion from the annular portion 91 located on the upstream side of the air flow to the column portion 93. ing. A plurality of holding recesses 96 provided between the pockets 94 adjacent in the circumferential direction are formed in the grease retaining portion 98. When viewed from the radial direction, the holding recess 96 has a substantially triangular shape in which two sides are curved along the contour of the pocket 84. The holding recess 96 is formed so as not to communicate with the inner ring raceway surface.

  The inner diameter portion of the grease retaining portion 98 is in close proximity to a counter bore (not shown) of the inner ring that is a cylindrical surface. As a result, even when an air flow is generated in the bearing space, the initially sealed grease on the upstream side of the air flow is retained on the upstream side as it is, and the gap between the seal member located on the downstream side of the air flow and the inner ring The amount of grease leaking from the clearance can be greatly reduced. Further, since the holding recess 96 that encloses and holds the grease is formed so as not to communicate with the inner ring raceway surface, the outflow of grease is further suppressed. Further, by providing the grease retaining portion 98, the strength of the annular portion 91 can be ensured even if a plurality of holding recesses 96 are formed.

  In addition, this invention is not limited to each embodiment mentioned above, A change, improvement, etc. are possible suitably. In each of the above-described embodiments and modifications, an example in which the rolling bearing is an angular ball bearing has been shown, but a deep groove ball bearing or other bearings may be used. In the above-described embodiment, the cause of the air flow in the rolling bearing has been described as being caused by the counter bore of the inner ring of the angular ball bearing. However, the present invention is not limited to this, and the rolling bearing is incorporated in, for example, a turbocharger. Even when there is a pressure difference from the outside of the bearing, such as when a supported shaft is supported, an air flow is generated in the rolling bearing, and the present invention can be applied.

  INDUSTRIAL APPLICABILITY The present invention is applicable to a bearing in which an air flow is generated in the axial direction, for example, a bearing used for high-speed operation, in which a seal member for sealing a bearing space is provided and grease lubricated. is there.

10, 10 ', 10A, 10A', 10B Rolling bearing 15 Ball 20 Outer ring 22 Outer ring raceway surface 30 Inner ring 32 Inner ring raceway surface 40, 60, 70, 80, 80 ', 80'', 90 Cage 50, 55 Seal member 78, 98 Grease retaining part 85, 86, 87, 96 Holding recess 89 Scraping part

Claims (4)

An outer ring having an outer ring raceway surface formed on the inner peripheral surface, an inner ring having an outer ring raceway surface formed on the outer peripheral surface, and a plurality of rolling elements disposed between the outer ring raceway surface and the inner ring raceway surface so as to be capable of rolling. A moving body, a cage for holding the plurality of rolling elements, and a pair of seal members disposed on both sides in the axial direction for sealing the bearing space between the outer ring and the inner ring, and lubricating the bearing space A rolling bearing that encloses the agent and has an air flow in the axial direction,
Encapsulating the lubricant from the upstream side of the air flow;
The rolling bearing according to claim 1, wherein the lubricant initially disposed upstream of the center in the axial direction of the rolling element is 80% or more of the total lubricant enclosed in the bearing space.   2. The rolling bearing according to claim 1, wherein 50% or more of the total lubricant enclosed in the bearing space is initially disposed on an axial end surface of the cage located on the upstream side of the air flow. .   3. The rolling according to claim 1, wherein an axial end portion of the cage located on the upstream side of the air flow protrudes radially inward and is in close proximity to the outer peripheral surface of the inner ring. bearing.   The rolling bearing according to any one of claims 1 to 3, wherein a plurality of recesses for holding the lubricant are provided on an axial end surface of the cage located on the upstream side of the air flow. .

Images