Ball bearing

Abstract

To realize easy utilization of grease for lubrication, the grease reaching an inner lateral surface of a seal in an axial direction during a rotation of a ball bearing.SOLUTION: A seal 50 attached to an outer race 20 has a grease guide surface 54 inclined to guide grease G to a shoulder 23 of the outer race 20. The grease guide surface 54 is formed from an inner diameter side of the outer race 20 toward an outer diameter side of an inner race 10 and at least to a position on a diameter equal to a pitch circle diameter PCD of a plurality of balls 30.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sealed ball bearing in which grease is sealed inside the bearing. [Background technology]

[0002] Generally, ball bearings are filled with grease between the inner and outer rings to provide lubrication, and a seal is attached to the outer ring to prevent the grease from leaking outside the bearing.

[0003] The seal has an inner diameter lip and an outer diameter seal edge formed of elastomer. The outer ring has a seal groove that holds the outer diameter seal edge and a protruding shoulder between the ball and the seal. The outer diameter seal edge contacts the seal groove and the shoulder, providing a seal between the outer ring and the seal. The inner diameter lip provides a seal between the inner ring and the seal.

[0004] Generally, the seal is located inside the outer ring to prevent the seal from increasing the space required to install the ball bearing, and does not have a portion located axially outward of the outer ring.

[0005] When the balls of a ball bearing revolve in the circumferential direction, the grease displaced by the balls and cage moves toward the inner periphery of the outer ring, the outer periphery of the inner ring, and the seal.

[0006] Conventionally, there is a ball bearing in which the cage is positioned away from the shoulder of the outer ring, and the inner circumference of the shoulder is formed with a slope that increases in diameter in the axial direction as it approaches the raceway surface of the outer ring. This type of ball bearing makes it easier for grease that reaches the shoulder of the outer ring to flow toward the raceway surface of the outer ring using the slope of the shoulder (Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-164122 Summary of the Invention [Problem to be solved by the invention]

[0008] If the width of the outer ring of a ball bearing is small, the axial distance between the axially inner side of the seal that fits inside the outer ring and the balls and cage becomes small, making it easier for grease that is pushed toward the seal when the ball bearing rotates to reach the seal.

[0009] In the ball bearing of Patent Document 1, there is an axial distance between the seal and the inner circumference of the shoulder of the outer ring that is approximately the width of the seal groove in the outer ring. As a result, even if grease reaches the seal when the ball bearing rotates and flows toward the outer ring due to centrifugal force, it is difficult for it to reach the inner circumference of the shoulder of the outer ring, which makes it difficult to use for lubrication.

[0010] In view of the above background, an object of the present invention is to make it easier to utilize grease that reaches the seal when the ball bearing rotates for lubrication. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention employs Configuration 1, which is a ball bearing comprising: an inner ring, an outer ring, a plurality of balls arranged between the inner ring and the outer ring, a cage that holds these balls, grease placed between the inner ring and the outer ring, and a seal attached to the outer ring, wherein the seal has an outer diameter side seal end and an inner diameter side lip portion formed of elastomer, the outer ring has a seal groove that holds the outer diameter side seal end and a shoulder that protrudes between the balls and the seal, the outer diameter side seal end contacts the shoulder and the seal groove to seal between the outer ring and the seal, the inner diameter side lip portion seals between the inner ring and the seal, and the seal has an inclined grease guide surface that is formed from the inner diameter side of the outer ring toward the outer diameter side of the inner ring, and is formed at least to a position equal to the pitch circle diameter PCD of the plurality of balls.

[0012] When a ball bearing rotates, grease is pushed toward the seal by the balls and cage. Centrifugal force causes the grease pushed toward the seal to flow toward the outer ring through the gap between the cage and the seal. The grease flowing toward the outer ring is guided by the grease guideway of the seal and approaches the inner circumference of the shoulder of the outer ring. At a position on the same diameter as the pitch circle diameter PCD of multiple balls, the gap between the seal and the balls is narrow, making it easy for the grease to reach the seal. Therefore, if the grease guideway is formed at least up to a position on the same diameter as the pitch circle diameter PCD, the grease pushed toward the seal will easily reach the grease guideway, and will be more easily utilized for lubrication by the guide of the grease guideway.

[0013] In the above configuration 1, configuration 2 can be adopted in which the seal is housed between the inner ring and the outer ring.

[0014] When the seal is housed between the inner and outer rings as in the above configuration 2, the axial distance between the balls and the seal is narrow, which makes it easier for the grease guide surface to be effective.

[0015] In the above configuration 1 or 2, a configuration 3 can be adopted in which the grease guide surface extends from a position of the outer ring that faces the shoulder in the radial direction.

[0016] According to the above configuration 3, the grease that has reached the grease guide surface can be guided to a position radially opposite the shoulder of the outer ring, making it easier for the grease to flow toward the shoulder.

[0017] In the above configuration 1 or 2, a configuration 4 can be adopted in which the grease guide surface is in contact with the shoulder of the outer ring.

[0018] According to the above configuration 4, the grease that has reached the grease guide surface can be guided to the shoulder of the outer ring.

[0019] In any one of the above configurations 1 to 4, a configuration 5 can be adopted in which the cage and the shoulder of the outer ring face each other with a gap in the radial direction. Note that the cage and the shoulder of the outer ring do not necessarily face each other in parallel.

[0020] According to the above configuration 5, the grease pushed against the side surface of the cage can be guided by the grease guide surface and directed from between the cage and the shoulder toward the inner periphery of the shoulder.

[0021] In the above configuration 5, a configuration 6 can be adopted in which the acute inclination angle of the grease guide surface relative to the radial direction is set to 11° or more.

[0022] In order for the grease guide surface to guide the grease to the shoulder of the outer ring, it is preferable to position the shoulder as close as possible to the outer ring side edge of the grease guide surface. The smaller the acute inclination angle of the grease guide surface relative to the radial direction, the closer the grease guide surface will be to the side of the cage. For a standard ball bearing with an outer ring width of approximately 20 mm, it is difficult to set the axial distance between the seal and the cage greater than 3 mm. In such cases, if the inclination angle of the grease guide surface is less than 10°, there is a concern that the grease guide surface and the cage may interfere with each other. If the inclination angle is 11° or greater, as in configuration 6 above, interference between the two can be avoided. From a geometrical perspective, the inclination angle of the grease guide surface cannot exceed 90°.

[0023] In any one of the above configurations 1 to 6, a configuration 7 can be adopted in which the shoulder of the outer ring has a slope whose diameter increases as it approaches the ball in the axial direction.

[0024] According to the seventh aspect, the grease that has reached the slope of the shoulder can be made to flow more easily toward the ball side (that is, toward the raceway surface of the outer ring) due to the inclination of the slope.

[0025] In the above-described configuration 7, a configuration 8 can be adopted in which the cage and the shoulder of the outer ring face each other with a radial gap therebetween, and the inclination angle of the inclined surface of the shoulder relative to the axial direction is an acute angle of 23° or less.

[0026] The larger the diameter of the inclined shoulder of the outer ring, the more difficult it is to raise the shoulder side of the raceway of the outer ring, making it more likely that the balls will ride up on the shoulder improperly (the contact ellipse between the raceway surface of the outer ring and the balls will extend beyond the raceway surface). Furthermore, the greater the acute angle of the inclination of the shoulder inclined surface relative to the axial direction, the more the seal-side end of the inclined surface will be positioned radially inward, narrowing the radial distance between the shoulder and the cage. Setting the inclination angle to 23° or less, as in configuration 8, ensures sufficient ride-up resistance of the ball bearing while avoiding interference between the inner circumference of the shoulder and the cage. The inclination angle may be greater than 0°.

[0027] In the above configuration 7 or 8, a configuration 9 can be adopted in which the shoulder of the outer ring has a flat surface extending along the axial direction at a position between the inclined surface and the seal.

[0028] According to the above-mentioned configuration 9, the grease guided to the shoulder of the outer ring by the grease guide surface is retained at the flat surface of the shoulder, so that excessive supply of grease to the raceway surface of the outer ring can be suppressed. [Effects of the Invention]

[0029] As described above, by employing the above configuration 1, the present invention can make it easier to utilize the grease that reaches the seal when the ball bearing rotates for lubrication. [Brief explanation of the drawings]

[0030] [Figure 1] 1 is a cross-sectional view showing a ball bearing according to a first embodiment of the present invention; [Figure 2] FIG. 10 is a cross-sectional view showing a ball bearing according to a second embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view showing a ball bearing according to a third embodiment of the present invention. [Figure 4]FIG. 10 is a cross-sectional view showing a ball bearing according to a fourth embodiment of the present invention. [Figure 5] FIG. 10 is a cross-sectional view showing a ball bearing according to a fifth embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view showing a ball bearing according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] A ball bearing according to a first embodiment (hereinafter simply referred to as "this ball bearing") as one example of the present invention will be described with reference to FIG. 1 of the accompanying drawings.

[0032] Hereinafter, the direction along the central axis of this ball bearing (not shown, same below) will be referred to as the "axial direction," the direction perpendicular to that central axis will be referred to as the "radial direction," and the circumferential direction going around the central axis will be referred to as the "circumferential direction." In particular, the direction axially toward the inside of the ball bearing (the side approaching the balls) will be referred to as the axial inner side, and the direction axially toward the outside of the ball bearing (the side away from the balls) will be referred to as the axial outer side. In Figure 1, the axial direction corresponds to the left-right direction, and the radial direction corresponds to the up-down direction.

[0033] This ball bearing comprises an inner ring 10, an outer ring 20, a plurality of balls 30 arranged between the inner ring 10 and the outer ring 20, a cage 40 that holds these balls 30, grease G (shown by a dotted pattern in Figure 1) placed between the inner ring 10 and the outer ring 20, and a pair of seals 50 attached to the outer ring 20.

[0034] The inner ring 10 has a raceway surface 11 formed on the outer periphery of the annular ring, and a pair of seal surfaces 12. The seal surfaces 12 are surfaces that cooperate with the seal 50 to seal in the grease G, and are located axially outward of the raceway surfaces 11.

[0035] The amount of grease G enclosed is generally specified as a percentage of the spatial volume inside the bearing. This percentage differs depending on whether the bearing is used under a grease lubrication system, in which grease alone lubricates the bearing for its entire life, or an oil lubrication system, in which oil is supplied from the outside of the bearing to the inside of the bearing and lubrication is provided by grease until this supply. This ball bearing may use either lubrication system.

[0036] The outer ring 20 has a raceway surface 21 formed on its annular inner circumference, a pair of seal grooves 22, and a pair of shoulders 23. The seal groove 22 is a groove for attaching the seal 50 to the outer ring 20, and is located axially outward of the raceway surface 21. The seal groove 22 is continuous around the entire circumferential direction, with the radial groove depth determined by the inner surfaces of the groove on both axially opposing sides. The shoulders 23 are solid portions that protrude radially between the balls 30 and the seal 50, and are continuous with the raceway surface 21 and the axially inner side of the seal groove 22. The inner diameter of the outer ring 20 (the smallest diameter of a circle inscribed in the outer ring 20) is determined by the inner circumference of the shoulders 23.

[0037] This ball bearing is configured as a deep groove ball bearing with double seals, and the inner ring 10, outer ring 20, and pair of seals 50 are each arranged symmetrically with respect to a virtual radial plane passing through the center of the bearing width as the boundary surface.

[0038] The cage 40 is shaped to face the shoulder 23 of the outer ring 20 at a radial distance, at a position closer to the seal 50 than the balls 30. The cage 40 is of a rolling element guided type, guided radially and axially by the balls 30. The cage 40 in the illustrated example is a corrugated cage, and the corrugated plate portion that faces the balls 30 in the axial direction faces the shoulder 23 radially so as to form a gap larger than the radial guide gap between the balls 30 and the cage 40.

[0039] The shoulder 23 of the outer ring 20 has a slope 23a whose diameter increases axially as it approaches the balls 30. The slope 23a may be composed of a single surface or multiple surfaces, and may be flat or curved. The slope 23a continues from the edge of the raceway surface 21 to the chamfered portion on the axially outer side of the shoulder 23. The acute inclination angle θa of the slope 23a relative to the axial direction is set to 23° or less. This value of the inclination angle θa is set so that the inclination of the slope 23a facilitates the grease G that reaches the slope 23a to flow toward the raceway surface 21, while also preventing the balls 30 from riding up onto the slope 23a and interference between the inner circumference of the shoulder 23 and the cage 40.

[0040] The seal 50 is made up of an outer diameter side seal end portion 51 and an inner diameter side lip portion 52 formed from an elastomer, and a core metal 53 bonded to the elastomer. The seal 50 is fitted inside the outer ring 20, and has no portion located axially outward of the end face 24 that defines the width of the outer ring 20.

[0041] The outer diameter side seal end 51 is an elastomer portion that comes into contact with the shoulder 23 and the seal groove 22 to seal between the outer ring 20 and the seal 50. The outer diameter side seal end 51 has a portion that enters the inside of the seal groove 22 and comes into contact with the seal groove 22, and a portion that comes into contact with the axially outer side surface of the shoulder 23, and covers the outer peripheral end of the core metal 53 in both the radial and axial directions. The seal groove 22 holds the outer diameter side seal end 51 so that it does not move in the radial and axial directions.

[0042] The inner diameter side lip portion 52 is an elastomer portion that cooperates with the seal surface 12 of the inner ring 10 to seal the grease G. The inner diameter side lip portion 52 protrudes radially from the core metal 53 toward the inner ring 10, and has a side lip that does not contact the seal surface 12, and a main lip that contacts the seal surface 12. Note that there are no particular restrictions on the number of inner diameter side lips or whether they contact the inner ring side or not. The inner diameter side lip portion may also be a non-contact type.

[0043] The core metal 53 is an annular metal plate for increasing the rigidity of the seal 50. The core metal 53 may be omitted.

[0044] Of the axially inner side surface of seal 50, the portion that faces axially the space that continues radially from shoulder 23 to inner ring 10, the portion located axially outermost faces axially the center O of ball 30 (that is, this portion is located at a position that intersects with an imaginary cylindrical surface whose cylindrical axis is the bearing center axis and whose diameter is the same as the pitch circle diameter PCD of multiple balls 30. Hereinafter, the portion located on the same diameter as PCD will be referred to as the PCD-corresponding portion.) The pitch circle diameter PCD is the intermediate value between the bearing outer diameter (here, the outer diameter of outer ring 20) and the bearing inner diameter (here, the inner diameter of inner ring 10).

[0045] The PCD corresponding portion of the seal 50 is set at a position that divides the entire radial length of the illustrated seal 50 in half. Therefore, the outer diameter side of the seal 50 is the side closer to the outer ring 20 with the PCD corresponding portion as the boundary.

[0046] The seal 50 has a grease guide surface 54 that extends in a direction inclined axially outward from a portion located on the outer diameter side and axially inner side of the seal 50 toward the inner ring 10 in the radial direction. The grease guide surface 54 extends from a position radially opposite the contact portion between the shoulder 23 of the outer ring 20 and the outer diameter side seal end 51 and closer to the shoulder 23 than the cage 40, to a portion of the seal 50 corresponding to the PCD.

[0047] The grease guide surface 54 is formed over the entire circumferential direction, continuous with the outer seal end 51, by an elastomer bonded to the axially inner side of the core metal 53. In particular, the grease guide surface 54 is continuous with the axially inner side surface of the outer seal end 51. The seal groove 22 is retained so that the outer seal end 51 is maintained in a state pressed against the axially outer side surface of the shoulder 23 of the outer ring 20. For this reason, the vicinity of the continuous portion between the outer seal end 51 and the grease guide surface 54 is in contact with the axially outer side surface of the shoulder 23 across a width in the radial direction, and the grease guide surface 54 is in contact with the axially outer side surface of the shoulder 23 at the end of the grease guide surface 54 on the outer ring 20 side.

[0048] The acute inclination angle θb of the grease guideway surface 54 relative to the radial direction is set to 11° or greater. This value of the inclination angle θb is set to avoid interference between the grease guideway surface 54 and the cage 40 while providing the grease guideway surface 54 with an inclination that guides the grease G from the contact portion with the shoulder 23 toward the shoulder 23. In particular, in a JIS-compliant deep groove ball bearing having an outer ring 20 width of approximately 20 mm, the diameter of the balls 30 is 10 mm or greater, making it difficult to ensure an axial distance of 3 mm or greater between the cage 40 and the seal 50. As the inclination angle of the grease guideway surface 54 is reduced to less than 10° while maintaining the position of the end of the grease guideway surface 54 on the shoulder 23 side, the grease engagement surface approaches the cage 40 and extends beyond the PCD corresponding portion toward the inner ring 10, increasing the risk of interference with the cage 40.

[0049] Although the grease guide surface 54 is exemplified as a conical surface centered on the bearing central axis, the grease guide surface is not limited to this and may be composed of a single surface or multiple surfaces, and the surface may be flat or may have a curved shape.

[0050] The plate surface of the core metal 53 continues from the grease guide surface 54 toward the inner ring 10. The plate surface of the core metal 53 extends in the radial direction and continues to the heel portion of the inner diameter side lip portion 52.

[0051] When this ball bearing rotates, the grease G is agitated by the multiple revolving balls 30 and the cage 40, which rotates in the same direction as the balls 30. The grease G displaced by the balls 30 and the cage 40 passes between the inner periphery of the cage 40 and the outer periphery of the inner ring 10 toward the seal 50, or from the side of the cage 40 toward the seal 50. Therefore, the grease G passes through the space that continues radially from the shoulder 23 of the outer ring 20 to the inner ring 10 and heads toward the axially inner side surface of the seal 50. For this reason, most of the grease G that passes through the space that continues radially from the shoulder 23 to the inner ring 10 reaches the seal portion that faces the space in the axial direction and is located on the axially inner side surface of the seal 50.

[0052] Furthermore, under bearing operating conditions where the inner ring 10 is the rotating ring and the outer ring 20 is the stationary ring, the circumferential kinetic energy imparted to the grease G from the outer periphery of the inner ring 10, the balls 30, and the cage 40 causes the grease G to flow circumferentially, resulting in centrifugal force acting on the grease G. Under bearing operating conditions where the inner ring 10 is the stationary ring and the outer ring 20 is the rotating ring, the circumferential kinetic energy imparted to the grease G from the inner periphery of the outer ring 20, the balls 30, the cage 40, and the seal 50 causes the grease G to flow circumferentially, resulting in a stronger centrifugal force acting on the grease G. Regardless of the bearing operating conditions, most of the grease G that passes through the space that continues radially from the shoulder 23 to the inner ring 10 and reaches the axially inner side surface of the seal 50 flows under the action of centrifugal force through the gaps between the balls 30, the cage 40, and the seal 50 toward the outer ring 20 (see the flow schematically indicated by arrow A). The remaining grease G remains near the inner diameter side lip portion 52 to provide lubrication and sealing between the inner diameter side lip portion 52 and the seal surface 12 of the inner ring 10.

[0053] When the grease G reaches the axially inner side surface of the seal 50, it flows toward the outer ring 20 due to the action of centrifugal force as shown by arrow A. When it flows along the grease guide surface 54 located on the outer diameter side of the seal 50 near the shoulder 23, it is guided toward the inner circumference of the shoulder 23 by the inclination angle θb of the grease guide surface 54 (see the flow shown schematically by arrow B), making it easier to supply to the balls 30 and the raceway surface 21 of the outer ring 20 (i.e., easier to utilize for lubrication).

[0054] Here, the grease G flowing toward the seal 50 passes somewhere in the space that continues radially from the shoulder 23 to the inner ring 10 and reaches the axially inner side surface of the seal 50. Most of the grease G that reaches there is directed toward the outer ring 20 by the action of centrifugal force. As long as the grease G flowing toward the outer ring 20 is located axially outward of the shoulder 23, it will always be guided by the grease guide surface 54 to approach the inner circumference of the shoulder 23. This is because the grease guide surface 54 is in contact with the shoulder 23 and extends to the PCD corresponding portion that is located axially outermost among the axially inner side surface portions of the seal 50 that face the radially continuous space between the shoulder 23 and the inner ring 10 in the axial direction.

[0055] When the grease G reaches the inclined surface 23a on the inner circumference of the shoulder 23, part of the centrifugal force acting on the grease G is converted into kinetic energy that causes the grease G to flow toward the raceway surface 21 of the outer ring 20 due to the inclination angle θa of the inclined surface 23a, making it easy for the grease G to flow toward the raceway surface 21.

[0056] This ball bearing is as described above, and comprises an inner ring 10, an outer ring 20, a plurality of balls 30 arranged between the inner ring 10 and the outer ring 20, a cage 40 for holding these balls 30, grease G placed between the inner ring 10 and the outer ring 20, and a seal 50 attached to the outer ring 20, the seal 50 having an outer diameter side seal end 51 and an inner diameter side lip portion 52 formed by an elastomer, the outer ring 20 having a seal groove 22 for holding the outer diameter side seal end 51, and a seal groove 22 for holding the balls 30 and the seal The ball bearing has a shoulder 23 protruding between the outer ring 20 and the seal groove 22, an outer seal end 51 contacts the shoulder 23 and the seal groove 22 to seal between the outer ring 20 and the seal 50, an inner lip 52 seals between the inner ring 10 and the seal 50, and the seal 50 has an inclined grease guide surface 54 that is formed from the inner diameter side of the outer ring 20 toward the outer diameter side of the inner ring 10, and extends to at least a position equal to the pitch circle diameter PCD of the plurality of balls. As a result, when the ball bearing rotates, grease G that has been pushed toward the seal 50 by the balls 30 and the cage 40 flows through between the balls 30, the cage 40, and the seal 50 toward the outer ring 20 due to the action of centrifugal force, and is guided by the grease guide surface 54 to approach the inner circumference of the shoulder 23. At a position on the same diameter as the pitch circle diameter PCD of the balls 30, the gap between the seal 50 and the balls 30 / retainer 40 is narrow, making it particularly easy for grease G flowing toward the outer ring 20 to reach the seal 50. In this ball bearing, the grease guide surface 54 is formed at least up to a position on the same diameter as the pitch circle diameter PCD of a plurality of balls 30 (the PCD corresponding portion), so grease G pushed toward the seal 50 easily reaches the grease guide surface 54, and is therefore more easily utilized for lubrication by the guidance of the grease guide surface 54. In this way, this ball bearing can easily utilize the grease G that reaches the seal 50 for lubrication during rotation.

[0057] Furthermore, in this ball bearing, since the seal 50 is housed between the inner ring 10 and the outer ring 20, the axial distance between the balls 30, the retainer 40 and the seal 50 is narrow, so that the grease G pushed aside by the balls 30 and the retainer 40 can easily reach the grease guide surface 54, making it easier for the grease guide surface 54 to be effective.

[0058] Furthermore, in this ball bearing, the grease guide surface 54 is continuous with the shoulder 23 of the outer ring 20 , so that the grease G that has reached the grease guide surface 54 can be guided to the shoulder 23 .

[0059] Furthermore, in this ball bearing, the retainer 40 and the shoulder 23 of the outer ring 20 are opposed to each other with a radial gap between them, so that the grease G pushed aside to the side of the retainer 40 (the side closer to the seal 50) can be guided by the grease guide surface 54 and directed from between the retainer 40 and the shoulder 23 toward the inner circumference of the shoulder 23.

[0060] In addition, this ball bearing has an acute inclination angle θb of the grease guide surface 54 relative to the radial direction of 11° or more, thereby avoiding interference between the retainer 40 and the grease guide surface 54 of the seal 50.

[0061] In addition, this ball bearing has an inclined surface 23a whose diameter increases as the shoulder 23 of the outer ring 20 approaches the ball 30 in the axial direction, so that the inclination angle θa of the inclined surface 23a makes it easier for the grease G that reaches the inclined surface 23a to flow toward the ball 30 (i.e., toward the raceway surface 21 of the outer ring 20).

[0062] Furthermore, in this ball bearing, cage 40 and shoulder 23 of outer ring 20 face each other with a radial gap between them, and the acute inclination angle θa of slope 23a of shoulder 23 relative to the axial direction is set to 23° or less, thereby ensuring sufficient ride-on resistance of this ball bearing while avoiding interference between the inner periphery of shoulder 23 and cage 40. The groove depth of raceway surface 21 of outer ring 20 relative to both shoulders 23 is ensured to be the same as that of a standard deep groove ball bearing conforming to JIS standards, so that the ride-on resistance is not inferior to the standard specifications.

[0063] In this ball bearing, the grease guide surface 54 contacts the shoulder 23 of the outer ring 20, but it is not necessary for the grease guide surface to contact the shoulder. If the grease guide surface is extended toward the inner ring from the vicinity of the shoulder, for example, from a seal portion within 1 mm of the shoulder, the grease guided by the grease guide surface will be more likely to flow toward the shoulder and be more easily utilized for lubrication. An example of this is a second embodiment shown in Figure 2. The following discussion will focus solely on the differences from the first embodiment.

[0064] In the outer ring 60 according to the second embodiment, a sloped surface 63a is formed on the inner periphery of a shoulder 63 connecting the raceway surface 61 and the seal groove 62, facing the raceway surface 61, and a flat surface 63b is formed on the seal groove 62 side of the sloped surface 63a. The flat surface 63b extends along the axial direction and continues to the chamfered portion of the shoulder 63. As a result, the inner diameter of the shoulder 63 is larger than in the first embodiment.

[0065] The grease guide surface 71 of the seal 70 extends toward the inner ring 80 from a position radially facing the axially outer side surface of the shoulder 63. The distance between the end of the grease guide surface 71 on the outer ring 60 side and the shoulder 63 is set to be less than 1 mm.

[0066] Furthermore, the grease guide surface 71 extends to a position closer to the inner ring 80 than the PCD corresponding portion.

[0067] In addition, the outer diameter side seal end 73 located between the core metal 72 and the outer ring 60 has been modified to a shape that contacts the axially outer side surface of the shoulder 63 at a position closer to the radial outward position than in the first embodiment, in accordance with the enlargement of the inner diameter of the shoulder 63. The inner diameter side lip portion 74 has been modified to a shape that has an axial lip portion that contacts the seal surface 81 of the inner ring 80 and a radial lip portion that contacts the groove shoulder portion on the axially outer side of the seal surface 81. The radial distance between the cage 90 and the shoulder 63 is set narrower than in the first embodiment. In addition, the plate thickness of the cage 90 is thicker than in the first embodiment, and the axial distance between the seal 70 and the cage 90 is narrower than in the first embodiment.

[0068] As the grease guide surface 71 is extended further toward the inner ring 80 than in the first embodiment, the elastomer covering the axially inner side surface of the core 72 forms a continuous line with the heel portion of the inner diameter lip 74 and the grease guide surface 71. When a rubber material is used as the elastomer and the core 72 is vulcanized to manufacture the seal 70, an exposed core portion is required to horizontally support the core 72 when it is inserted into a mold. If this exposed core portion is located on the side surface on the inner side of the seal bearing, it is difficult to form the grease guide surface 71 around the entire circumference with the cross-sectional shape shown in the figure, so it is preferable to expose the axially outer side surface of the core 72 at multiple locations around the circumference.

[0069] During rotation of the ball bearing according to the second embodiment, grease G that reaches the grease guide surface 71 is guided by the grease guide surface 71 to a position radially opposite the shoulder 63. When the grease G leaves the end of the grease guide surface 71 on the outer ring 60 side toward the shoulder 63, centrifugal force causes the grease G to move toward the shoulder 63 and quickly reach the vicinity of the flat surface 63b. Because the flat surface 63b is aligned along the axial direction, the grease G that reaches this point is not particularly encouraged to flow toward the raceway surface 61 of the outer ring 60. Therefore, compared to the first embodiment, the grease G that reaches the flat surface 63b is retained near the corner formed by the flat surface 63b and the axially inner side surface of the seal 70, and is less likely to move toward the inclined surface 63a. This makes it less likely that an excess of grease G will be supplied to the raceway surface 61 of the outer ring 60.

[0070] As described above, in the ball bearing of the second embodiment, the grease guide surface 71 extends from a position radially opposite the shoulder 63 of the outer ring 60, so that the grease G that reaches the grease guide surface 71 can be guided to a position radially opposite the shoulder 63, making it easier for it to flow toward the shoulder 63 (see arrows A and B).

[0071] Furthermore, in the ball bearing according to the second embodiment, shoulder 63 of outer ring 60 has flat surface 63b extending in the axial direction at a position between inclined surface 63a and seal 70, so that grease G guided to shoulder 63 by grease guide surface 71 is retained at flat surface 63b, thereby preventing excessive supply of grease G to raceway surface 61 of outer ring 60. Therefore, the ball bearing according to the second embodiment is suitable when it is desired to prevent an increase in bearing torque due to the stirring resistance of grease G.

[0072] In the above-described embodiments, examples have been shown in which grease guide surfaces, inclined surfaces, etc. are formed on both seals of the ball bearing and on both shoulders of the outer ring, but depending on the required lubrication efficiency of the grease G and the ability to prevent excessive supply, it is also possible to form grease guide surfaces, inclined surfaces, etc. on only one seal or shoulder. One such example is shown in Figure 3 as a third embodiment.

[0073] In the outer ring 100 according to the third embodiment, a sloped surface 101a and a flat surface 101b are formed only on one shoulder 101, and no slope is formed on the opposite shoulder 103 across the raceway surface 102. The sloped surface is omitted from the opposite shoulder 103, and a cylindrical surface 103a is formed on the inner circumference of the shoulder 103 that continues axially from the raceway surface 102 to the chamfered portion on the axially outer side.

[0074] The cage 110 has a shape that does not have a portion that faces the shoulder 101 on one side in the radial direction. The cage 110 has a crown shape that has one ring portion 111 and a plurality of pillar portions 112.

[0075] The seal 120 closer to the shoulder 103 does not have a grease guide surface. The axially inner side surface of the core 121 is exposed except for the areas necessary for bonding the outer seal end 122 and the inner lip 123 to the core 121. By eliminating the grease guide surface from the seal 120, interference between the ring portion 111 and the seal 120 is avoided.

[0076] The ball bearing of the third embodiment makes it easier to utilize the grease G that has reached the axially inner side of the seal 50 for lubrication by using the grease guide surface 54 of the seal 50 on one side and the inclined surface 101a of the shoulder 101 on one side, while preventing excessive supply of grease G to the raceway surface 102 by using the flat surface 101b of the shoulder 101 on one side, the omission of the inclined surface from the shoulder 103 on the opposite side, and the omission of the grease guide surface from the seal 120 on the opposite side.

[0077] A fourth embodiment as another example is shown in Fig. 4. The fourth embodiment is a further modification of the third embodiment, and only the changes from the third embodiment will be described here.

[0078] The outer ring 130 according to the fourth embodiment has a sloped surface 132a and a flat surface 132b formed on each of the shoulders 132 on both sides of the raceway surface 131. Compared to the third embodiment, the ball bearing according to the fourth embodiment can more easily utilize grease G for lubrication by virtue of the sloped surface 132a of the shoulder 132 closer to the seal 120, which makes it easier for grease G to flow onto the raceway surface 131 of the outer ring 130 (see arrow C).

[0079] As a further modification of the second embodiment, a ball bearing according to a fifth embodiment is shown in Fig. 5. Note that only the modifications from the second embodiment will be described here.

[0080] In the seal 140 according to the fifth embodiment, the outer seal end 141, the inner lip 142, and the grease guide surface 143 are formed continuously around the entire circumferential circumference by an elastomer, and there is no exposed portion on the axially inner side surface of the core 144. The core 144 has an axially outer side surface region 144a that is exposed to the outside of the bearing around the entire circumferential circumference or at multiple locations around the circumferential circumference. The seal 140 is formed by vulcanization bonding a rubber material (elastomer) to the core 144. During the vulcanization bonding, the core 144 is supported horizontally at the radial side surface region 144a of the core 144 inserted into a mold, and can be molded and bonded to completely cover the axially inner side surface of the core 144. Therefore, the grease guide surface 143, the outer seal end 141, and the inner lip 142 are formed continuously around the entire circumferential circumference on the axially inner side surface of the seal 140.

[0081] In the above-described embodiments, the grease guide surface is formed of an elastomer, but it may also be formed of a core bar. As an example, a sixth embodiment is shown in Fig. 6. Note that the sixth embodiment is a further modification of the second embodiment, and only the changes from the second embodiment will be described here.

[0082] In the seal 150 according to the sixth embodiment, the core 151 has a plate portion that is formed in a conical shape to form the grease guide surface 151a. To position the grease guide surface 151a near the shoulder 63 of the outer ring 60, a flange bent portion 151b that forms the outer peripheral end of the core 151 is bent axially outward. The elastomer covers the axially inner side surface of the core 151 excluding the grease guide surface 151a, and also completely covers the axially outer side surface of the core 151. The adhesive area of ​​the outer seal end 152 and the inner lip portion 153 to the axially inner side surface of the core 151 is sufficiently secured by the plate portion excluding the grease guide surface 151a.

[0083] In each of the above-described embodiments, a deep groove ball bearing is exemplified, but it is also possible to change to an angular contact ball bearing.

[0084] Furthermore, in each of the above-described embodiments, a wave-shaped cage or a crown-shaped cage is exemplified as the cage, but it is also possible to change to a squirrel-cage cage in which two ring portions are separated by a plurality of pillar portions.

[0085] Furthermore, in each of the above-described embodiments, it does not matter whether the inner ring or the outer ring rotates. When a ball bearing is used under conditions in which the inner ring is stationary and the outer ring is rotating, rotational energy can be imparted to the grease from the axially inner side surface of the seal, including the grease guideway. On the other hand, when a ball bearing is used under conditions in which the inner ring is rotating and the outer ring is stationary, the seal and the outer ring are stationary, so rotational energy cannot be imparted to the grease from the axially inner side surface of the seal, and the grease is guided by the inclination of the grease guideway, utilizing the centrifugal force acting on the grease. The outer ring rotation condition is superior in that it is possible to impart rotational energy to the grease from the grease guideway, causing a relatively strong centrifugal force to act on the grease.

[0086] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0087] 10, 80 inner ring 20, 60, 100, 130 outer ring 21, 61, 102, 131 raceway surface 22, 62 Seal groove 23, 63, 101, 132 Shoulder 23a, 63a, 101a, 132a slopes 30 balls 40, 90, 110 retainer 50, 70, 140, 150 stickers 51, 73, 141, 152 Outer diameter seal end 52, 74, 142, 153 Inner diameter lip 54, 71, 143, 151a Grease guideway 63b, 101b, 132b flat surface Grease

Claims

1. The bearing comprises an inner ring, an outer ring, a plurality of balls arranged between the inner ring and the outer ring, a cage that holds the balls, grease placed between the inner ring and the outer ring, and a seal attached to the outer ring, the seal has an outer diameter seal end and an inner diameter lip formed of an elastomer; the outer ring has a seal groove that holds the outer diameter side seal end and a protruding shoulder between the ball and the seal, the outer diameter side seal end contacts the shoulder and the seal groove to seal between the outer ring and the seal, the inner diameter side lip portion seals between the inner ring and the seal, the seal has an inclined grease guide surface; The grease guide surface is formed from the inner diameter side of the outer ring toward the outer diameter side of the inner ring, and is formed at least up to a position on the same diameter as the pitch circle diameter PCD of the plurality of balls.

2. 2. A ball bearing according to claim 1, wherein said seal is housed between said inner ring and said outer ring.

3. 3. A ball bearing according to claim 1, wherein the grease guide surface extends from a position of the outer ring radially opposite the shoulder.

4. 3. A ball bearing according to claim 1, wherein the grease guide surface is in contact with the shoulder of the outer ring.

5. 3. A ball bearing according to claim 1, wherein the cage and the shoulder of the outer ring face each other with a radial gap therebetween.

6. 6. A ball bearing according to claim 5, wherein the acute inclination angle of said grease guide surface relative to the radial direction is set to be 11 degrees or more.

7. 3. A ball bearing according to claim 1, wherein the shoulder of the outer ring has a slope whose diameter increases as it approaches the ball in the axial direction.

8. The retainer and the shoulder of the outer ring face each other with a gap therebetween in the radial direction, 8. A ball bearing according to claim 7, wherein the inclination angle of the inclined surface of the shoulder relative to the axial direction is set to be 23° or less.

9. 8. A ball bearing according to claim 7, wherein the shoulder of the outer ring has a flat surface extending axially between the beveled surface and the seal.

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