JP2008175329A - Rolling bearing cage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing cage superior in torque reducing performance and seizure resistance under minimum lubrication. <P>SOLUTION: One annular part 20 of the cage 5 consists of a cylindrical portion 30 in a cylindrical shape, and a plurality of first protruded portions 31 protruded from the cylindrical portion 30 outward in the radial direction. One peripheral phase angle between the first protruded portions 31 neighboring each other in the peripheral direction is set to be greater than 180°. The gravity center of the cage 5 is located at a space from the center axis of the cylindrical portion 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a rolling bearing cage, and more particularly to a rolling bearing cage that is suitable for holding a rolling element of a rolling bearing used in a micro lubrication environment.

  Conventionally, as a rolling bearing cage (hereinafter simply referred to as a cage), there is one described in JP-A-2003-278774 (Patent Document 1).

  This cage is a crown-shaped cage. Each of the outer peripheral surface and inner peripheral surface of the cage is a rib that extends in the axial direction from the outer edge in the axial direction to the inner edge of the cage at the midpoint between two pockets adjacent in the circumferential direction. have.

  The same number of ribs as the pockets are present on the outer peripheral surface and the inner peripheral surface of the cage. The center of gravity of the combination of all the ribs is located on the rotation axis of the cage. In this way, the conventional cage has a high roundness.

In the conventional cage described above, ribs are formed on both the outer circumferential surface and the inner circumferential surface of the cage to suppress the torque fluctuation of the cage and the generation of cage noise, thereby reducing the torque of the cage and reducing the noise. It is trying to realize.
Japanese Patent Laid-Open No. 2003-278774 (FIG. 1)

  Here, as will be described in detail below, the present inventor, in the case of a small amount of lubricating oil, depending on the rotation and load conditions, a cage that is symmetric with respect to the rotation axis including the conventional cage is not sintered. I found it easy to attach and a large torque.

  Accordingly, an object of the present invention is to provide a rolling bearing cage that is excellent in torque reduction and seizure resistance, particularly under a small amount of lubrication.

In order to solve the above problems, the rolling bearing cage of the present invention is
Having an annular part and a pillar part forming a pocket for accommodating the rolling elements,
The annular portion has a protruding portion protruding in the radial direction so as to contact the raceway,
The protrusion is single or plural,
When there are a plurality of protrusions, at least one of the lengths between the two protrusions adjacent in the circumferential direction has a circumferential phase angle greater than 180 °.

  The phrase “so as to contact the bearing ring” means that “the time during which the rolling bearing having the retainer of the present invention is in operation is longer in contact with the bearing ring”. In other words, the protruding portion may not always be in contact with the raceway. That is, while the rolling bearing having the cage according to the present invention is in operation, the time during which the protruding portion is in contact with the raceway is such that the portion other than the projection of the annular portion is the raceway. The protrusion may have any shape as long as it satisfies the condition that it is longer than the time of contact with the protrusion.

  The phase angle is a value representing the circumferential length of the annular portion when the entire circumference is 360 °. For example, the circumferential length occupying 1/3 of the entire circumference is 120 °. That is, it is the length when the length in the circumferential direction is expressed by the arc method (however, [°] is used instead of [radian]).

  Further, the protruding portion of the annular portion may be smoothly connected to a portion other than the protruding portion of the annular portion, and the protruding portion of the annular portion is not smooth to the portion other than the protruding portion of the annular portion. You may be connected by. When this is expressed mathematically, the connection between the protruding portion of the annular portion and the portion other than the protruding portion of the annular portion may be a differentiable connection or a connection having a non-differentiable location. It may be.

  Among those skilled in the art, it is believed that the higher the roundness of the cage, the higher the performance, such as superior torque reduction capability, and the idea of intentionally breaking the roundness of the cage. Does not exist among those skilled in the art.

  However, the present inventor has discovered the following phenomenon, and in the environment of a small amount of lubrication, when the cage in which the roundness of the cage is intentionally broken locally exhibits extremely excellent performance Found that there is.

  Specifically, the present inventor limits the amount of lubricant to, for example, the nanoliter level (the amount of supply per one time into the bearing is nanoliter (nl) level), and the lubricant stirring resistance The following facts were discovered while conducting experiments under conditions where the value of was drastically reduced.

  That is, it has been discovered that there are cages that rotate stably and cages that do not easily rotate when the amount of lubricant is considerably limited. As a result of comparing and contrasting the cage that rotates stably and the cage that does not rotate easily, it has been found that the cage that rotates more stably has a lower roundness. That is, it has been found that a cage having a high roundness is difficult to rotate, whereas a cage having a low roundness may rotate stably.

  In addition, depending on the rotation and load conditions, a cage with high roundness is likely to seize on the outer peripheral surface of the cage, and the amount of lubricant necessary to prevent seizure increases. It was also discovered that a cage having a low circularity hardly causes seizure even when the amount of lubricant is extremely small.

  The reason why these phenomena occur is not clear. However, the present inventor considers this reason as follows. In other words, in a micro lubrication environment, in a cage with high roundness where the cage contacts the raceway everywhere in the circumferential direction of the cage, oil film breakage of the cage tends to occur everywhere and It is considered that the cage becomes difficult to rotate and the wear of the cage is severe.

  Also, in a cage with a low roundness where the circumferential location of the cage that comes into contact with the raceway is limited, seizure occurs even if the cage rotates stably and the cage is lubricated in a minute amount. The reason why it is difficult to touch is that the place where it is easy to contact, that is, the place where it is easy to wear, is limited. This is probably because a lubricant film is likely to be formed at a location where the contact is easy.

  According to the present invention, when the annular portion has a protruding portion protruding in the radial direction so as to contact the race, the protruding portion is single or plural, and the protruding portion is plural In addition, since the circumferential phase angle of at least one of the protrusions adjacent in the circumferential direction is larger than 180 °, the roundness of the cage can be lowered, and the protrusion The portion can be brought into contact with the raceway more preferentially than the portion other than the protruding portion of the annular portion. Therefore, the torque of the rolling bearing can be reduced and the life of the rolling bearing can be extended as compared with the case where a cage with high roundness is used in a micro lubrication environment.

  Moreover, in one Embodiment, the said annular part has a cylindrical cylindrical part, and the said protrusion part is a convex part which protruded in the said radial direction from the outer peripheral surface of the said cylindrical part.

  According to the embodiment, since the protruding portion is a protruding portion protruding from the outer peripheral surface of the cylindrical portion, the protruding portion can be easily formed. Further, since the number of protrusions can be easily adjusted and the amount of protrusion at each protrusion can be easily adjusted, the degree of unbalance of the cage can be easily and precisely adjusted.

  In one embodiment, both the inner peripheral surface and the outer peripheral surface of the annular portion are substantially cylindrical surfaces, and the central axis of the inner peripheral surface and the central axis of the outer peripheral surface are parallel to each other, The central axis of the inner peripheral surface is located at a distance from the central axis of the outer peripheral surface.

  According to the rolling bearing cage of the present invention, the annular portion has a protruding portion that protrudes in the radial direction so as to contact the race, the protruding portion is single or plural, and the protruding portion is In the case of a plurality, since the circumferential phase angle of at least one of the protrusions adjacent in the circumferential direction is larger than 180 °, the roundness of the cage can be lowered. At the same time, the protruding portion can be brought into contact with the raceway more preferentially than the portion of the annular portion other than the protruding portion. Therefore, the torque of the rolling bearing can be reduced and the life of the rolling bearing can be extended as compared with the case where a cage with high roundness is used in a micro lubrication environment.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is an axial sectional view of a ball bearing including a rolling bearing cage (hereinafter simply referred to as a cage) 5 according to a first embodiment of the present invention.

  The ball bearing is disposed between the main shaft of the machine tool and the housing. This ball bearing is lubricated by oil-air lubrication, and is used in an environment where the amount of lubricant used for lubrication is relatively small. This ball bearing includes an outer ring 1, an inner ring 2, a plurality of balls 3 as rolling elements, and a cage 5 according to the first embodiment of the present invention.

  The outer ring 1 has a raceway groove 11, a first shoulder 15 and a second shoulder 16 as a raceway surface, while the inner ring 2 has a raceway groove 12 as a raceway surface. The first shoulder 15 is located on one side of the raceway groove 11 in the axial direction, and the second shoulder 16 is located on the other side of the raceway groove 11 in the axial direction. The plurality of balls 3 are arranged at intervals in the circumferential direction between the raceway groove 11 of the outer ring 1 and the raceway groove 12 of the inner ring 2 while being held by the cage 5.

  The cage 5 includes a first annular portion 20, a second annular portion 21, and a plurality of pillar portions (not shown). Each of the column portions connects the first annular portion 20 and the second annular portion 21. The plurality of column portions are arranged at intervals in the circumferential direction of the first annular portion 20.

  The first annular portion 20 includes a cylindrical first cylindrical portion 30 and a first convex portion 31 as an example of a protruding portion. The first convex portion 31 protrudes outward in the radial direction from the outer peripheral surface of the first cylindrical portion 30. In the first embodiment, the first convex portion 31 is exaggerated for easy understanding, and the radial height of the first convex portion 31 is drawn much larger than actual. The first convex portion 31 has a rectangular cross section in the axial cross section shown in FIG. The axially outward end surface of the first convex portion 31 is an extension surface of the axially outward end surface of the first annular portion 20, and the axially inward end surface of the first convex portion 31. Is an extended surface of the inner end face of the first annular portion 20 in the axial direction.

  The second annular portion 21 includes a cylindrical second cylindrical portion 40 and a second convex portion 41 as an example of a protruding portion. The second convex portion 41 protrudes outward in the radial direction from the outer peripheral surface of the second cylindrical portion 40. In the first embodiment, the second convex portion 41 is exaggerated for easy understanding, and the radial height of the second convex portion 41 is drawn much larger than actual. The second convex portion 41 has a rectangular cross section in the axial cross section shown in FIG. The axially outer end surface of the second convex portion 41 is an extension surface of the axially outer end surface of the second annular portion 21, and the axially inner end surface of the second convex portion 41. Is an extended surface of the inner end face of the second annular portion 21 in the axial direction.

  As shown in FIG. 1, the first annular portion 20 is opposed to the first shoulder portion 14 in the radial direction with a slight gap, while the second annular portion 21 is slightly opposite the second shoulder portion 15. Opposite the radial direction through a gap. The first shoulder 14 guides the first annular portion 20, while the second shoulder 15 guides the second annular portion 21.

  In FIG. 1, reference numeral 25 indicates the outer peripheral surface of the first cylindrical portion 30, and reference numeral 26 indicates the outer peripheral surface of the second cylindrical portion 40. These lines 25 and 26 are not actually visible, but are shown in FIG. 1 for convenience to facilitate understanding.

  FIG. 2 is a schematic view of the first annular portion 20 as viewed from the direction indicated by the arrow a in FIG. 1, that is, from the outside in the axial direction. Note that the cage portion of the ball bearing shown in FIG. 1 corresponds to the sectional view taken along the line AA in FIG.

  As shown in FIG. 2, the axial end surface of the first convex portion has a substantially arc shape. There are three first convex portions 31. The three first convex portions 31 are located at intervals in the circumferential direction of the first annular portion 20. A phase angle in one circumferential direction between two first convex portions 31 adjacent in the circumferential direction is larger than 180 °. 2, in the 1st convex part 47 and the 1st convex part 48 which are the pair of the 1st convex part 31 adjacent to the circumferential direction, the edge by the side of the 1st convex part 48 of the 1st convex part 47 And the circumferential phase angle at the portion between the first convex portion 48 and the end on the first convex portion 47 side is larger than 180 °. In this way, the center of gravity of the cage 5 is positioned with a distance from the central axis of the first cylindrical portion 30. In this way, the circularity of the cage 5 is intentionally broken so that the cage 5 is not balanced with respect to the central axis of the rolling bearing (the central axis of the outer ring 1).

  FIG. 3 is a partial cross-sectional view of the first cylindrical portion 30 and the outer ring 1 taken along a plane perpendicular to the central axis of the first cylindrical portion 30. As shown in FIG. 3, the first convex portion 31 faces the inner circumferential surface of the outer ring 1 in the radial direction with a slight gap. 2 and the lines with reference numbers 71 and 72 in FIG. 3 are lines that indicate the boundary between the first cylindrical portion 30 and the first convex portion 31, respectively. It is a line drawn for convenience to facilitate understanding.

  Although not described in detail, the second annular portion 21 has the same structure (shape and size) as the first annular portion 20. The second convex portion 41 of the second annular portion 21 is exactly opposed to the first convex portion of the first annular portion 20 in the axial direction of the first cylindrical portion 30.

  As described above, conventionally, it has been considered by those skilled in the art that the higher the roundness of a cage, the higher the performance, such as superior torque reduction capability. There is no idea among those skilled in the art that this is intentionally broken.

  However, the present inventors have found that there are cages that rotate stably and cages that do not easily rotate when the amount of lubricant is limited. As a result of comparing and contrasting the cage that rotates stably and the cage that does not rotate easily, it has been found that the cage that rotates more stably has a lower roundness. That is, it was discovered that a cage with high roundness is difficult to rotate depending on rotation, load, and lubrication conditions, while a cage with low roundness rotates stably.

  Also, depending on the rotation, load, and lubrication conditions, a cage with high roundness is likely to seize on the outer peripheral surface of the cage, and the amount of lubricant necessary to prevent seizure increases. It was also discovered that the cage having low roundness hardly causes seizure even when the amount of lubricant is extremely small.

  According to the cage 5 of the first embodiment, the first annular portion 20 has the first convex portion 31 and the second convex portion 41 protruding in the radial direction so as to contact the outer ring 1, and the first Each of the first convex portion 13 and the second convex portion 41 is plural, and the phase angle in one circumferential direction between the first convex portions 31 adjacent in the circumferential direction is larger than 180 °. In addition, since the phase angle in one circumferential direction between the second convex portions 41 adjacent to each other in the circumferential direction is larger than 180 °, the roundness of the cage 5 can be lowered. At the same time, the first and second convex portions 31 and 41 are brought into contact with the outer ring 1 more preferentially than the portions other than the first and second convex portions 31 and 41 of the first and second annular portions 20 and 21. can do. Therefore, the torque of the rolling bearing can be reduced and the life of the rolling bearing can be extended as compared with the case where a cage with high roundness is used in a micro lubrication environment.

  Further, according to the cage 5 of the first embodiment, since the projecting portions are the projecting portions 31 and 41 projecting in the radial direction from the cylindrical portions 30 and 40, the projecting portions can be easily formed. Further, since the number of protrusions can be easily adjusted and the amount of protrusion at each protrusion can be easily adjusted, the degree of unbalance of the cage 5 can be adjusted easily and precisely.

  In the cage 5 of the first embodiment, there are two locations between the circumferential directions in which the phase angle between the convex portions 31 and 41 adjacent in the circumferential direction is larger than 180 ° (first annular portion). In the present invention, there is at least one pair of convex portions adjacent in the circumferential direction, and between the convex portions adjacent in the circumferential direction. There may be only one portion between the circumferential directions in which the phase angle is greater than 180 °.

  As a specific example of this, the following case can be considered. That is, as an example, there are two annular portions, and at least one of the outer circumferential surface and the inner circumferential surface of at least one annular portion of the two annular portions has at least one pair of convex portions adjacent in the circumferential direction. There may be only one location between the circumferential direction in which a pair exists and the phase angle between adjacent convexes in the circumferential direction is greater than 180 °.

  As another example, the retainer is a so-called crown-shaped retainer, which has only one annular portion, and is a convex portion adjacent in the circumferential direction to at least one of the outer peripheral surface and the inner peripheral surface of the annular portion. There are cases where there is at least one pair, and there is only one portion between the circumferential directions in which the phase angle between the convexes adjacent in the circumferential direction is larger than 180 °.

  In the cage 5 of the first embodiment, the first and second annular portions 20 and 21 have a configuration in which convex portions protrude in the radial direction from the cylindrical cylindrical portion. The annular portion may have a configuration in which convex portions protrude in the radial direction from a conical portion whose outer peripheral surface and inner peripheral surface are conical surfaces.

  In the cage 5 of the first embodiment, the three convex portions 31 protrude from the outer peripheral surface of the first annular portion 20 at intervals in the circumferential direction. However, in the present invention, at least one annular portion is provided. Two protrusions may protrude in the circumferential direction from at least one of the outer peripheral surface and the inner peripheral surface of at least one of the outer peripheral surface and the inner peripheral surface of at least one annular portion Four or more convex portions may protrude from the circumferential direction at intervals.

  Further, in the cage 5 of the first embodiment, as shown in FIG. 4 which is a part of an axial sectional view of the first cylindrical portion 30, the first convex portion 61 has a first annular shape in the axial direction. The outer peripheral surface of the portion 20 existed from one end to the other end in the axial direction from end to end. However, in the present invention, as shown in FIG. 5 (FIG. 5 is a part of a sectional view in the axial direction of the cylindrical portion of the cage of the modification of the first embodiment), the convex portion 51 is an annular portion. The outer peripheral surface of 50 may not exist from one end to the other end in the axial direction, and may exist only in a part of the outer peripheral surface of the annular portion 50 in the axial direction. Further, the convex portion may exist from one end to the other end in the axial direction of the inner peripheral surface of the annular portion, and the convex portion may be provided from one end in the axial direction of the inner peripheral surface of the annular portion. It does not need to exist from end to end from end to end, and may exist only in part of the inner peripheral surface of the annular portion in the axial direction.

  In the cage 5 of the first embodiment, the first convex portion 31 has an arc shape in the radial sectional view. However, in the present invention, the first convex portion 31 has a convex shape in the radial sectional view. The part may have a shape other than the arc shape, such as a rectangular shape, an isosceles trapezoidal shape, or a substantially triangular shape. Further, in the cage 5 of the first embodiment, the first convex portion 31 has a rectangular shape in the sectional view in the axial direction. The shape may be other than a rectangular shape, such as an arc shape or an isosceles trapezoid shape.

  In addition, the cage 5 of the first embodiment is a ball bearing cage having a structure in which two annular portions are connected by a column portion. However, the cage of the present invention has an annular portion. There may be only one so-called crown-shaped cage.

  The cage 5 of the first embodiment is a ball bearing cage. However, the cage of the present invention is a ball bearing for a tapered roller bearing, a cage for a cylindrical roller bearing, or the like. A cage for a rolling bearing other than the bearing cage may be used.

(Second Embodiment)
FIG. 6 is an axial cross-sectional view of a ball bearing including a rolling bearing cage (hereinafter simply referred to as a cage) 105 according to a second embodiment of the present invention.

  In the cage 105 of the second embodiment, the description of the operations and effects common to the cage 5 of the first embodiment will be omitted, and only the configuration different from the cage 5 of the first embodiment will be described. To do.

  The cage 105 of the second embodiment is formed by connecting a first annular portion 120 and a second annular portion 121 with a plurality of pillar portions (not shown). The outer ring 101 of the ball bearing shown in FIG. 6 has a shoulder portion only on one side in the axial direction of the raceway groove. The outer peripheral surface of the first annular portion 120 is opposed to the inner peripheral surface 114 of the shoulder portion in the radial direction via a slight gap. The shoulder has a role of guiding the first annular portion 120. The first annular portion 120 may be in contact with the outer ring 101, while the second annular portion 121 is not in contact with the outer ring 101. The first annular portion 120 has a cylindrical cylindrical portion 130 and a convex portion 131 as an example of a protruding portion, while the second annular portion 121 is composed of only a cylindrical portion and does not have a convex portion. It has become.

  FIG. 7 is a schematic view of the first annular portion 120 as viewed from the direction indicated by the arrow b in FIG. 6, that is, from the outside in the axial direction. As shown in FIG. 7, the convex portion 131 is single and projects outward in the radial direction from the outer peripheral surface of the cylindrical portion 130. In the second embodiment, the convex portion 131 is drawn exaggerated for easy understanding, and the radial height of the convex portion 131 is drawn much larger than actual.

(Third embodiment)
FIG. 8 is a diagram corresponding to FIG. 2 (or FIG. 7) of the holder 205 of the third embodiment.

  In the third embodiment, both the inner peripheral surface 140 and the outer peripheral surface 141 of the annular portion 220 of the cage 205 are substantially cylindrical surfaces. The central axis P0 of the inner peripheral surface 140 and the central axis P1 of the outer peripheral surface 141 are parallel to each other, and the central axis P0 of the inner peripheral surface 140 is spaced from the central axis P1 of the outer peripheral surface 141. Is located.

  In the third embodiment, the distance between the P0 and the P1 is drawn much larger than the actual distance for easy understanding. Actually, the distance between P0 and P1 is very small.

  In the third embodiment, an intersection line 151 that intersects the outer peripheral surface 141 and a plane including the central axis P1 and the central axis P0 and has a long distance from the central axis P0 protrudes in the radial direction. It is a protruding part.

  Also in the third embodiment, as in the first and second embodiments, the intersecting line portion 151 that is the protruding portion collides with the outer ring (not shown) while the rolling bearing having the cage is in operation. The time during which the portion other than the intersection line 151 on the outer peripheral surface of the outer ring collides with the outer ring becomes longer. Therefore, in the third embodiment, as in the first and second embodiments, the torque of the rolling bearing having this cage can be reduced, and the life of the rolling bearing having this cage can be extended. it can.

It is sectional drawing of the axial direction of the ball bearing containing the cage for rolling bearings of 1st Embodiment of this invention. It is a schematic diagram when the 1st annular part of the holder | retainer of 1st Embodiment is the figure seen from the direction shown by the arrow a in FIG. 1, ie, the axial direction outward. It is a part of sectional drawing when a 1st cylindrical part and an outer ring | wheel are cut | disconnected by the plane perpendicular | vertical to the central axis of a 1st cylindrical part. It is a part of sectional drawing of the axial direction of a 1st cylindrical part. It is a part of sectional drawing of the axial direction of the cylindrical part of the holder | retainer of the modification of 1st Embodiment. It is sectional drawing of the axial direction of the ball bearing containing the cage for rolling bearings of 2nd Embodiment of this invention. It is a schematic diagram when the 1st cyclic | annular part of the holder | retainer of 2nd Embodiment is the figure seen from the direction shown by the arrow b in FIG. 6, ie, the axial direction outward. It is a figure corresponding to FIG. 2 in the holder | retainer of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,101 Outer ring 2,102 Inner ring 3,103 Ball 5,105 Cage 20,120 First annular part 21,121 Second annular part 30 First cylindrical part 31 First convex part 40 Second cylindrical part 41 Second convex part Part 130 Cylindrical part 131 Convex part 151 Intersection part

Claims (2)

Having an annular part and a pillar part forming a pocket for accommodating the rolling elements,
The annular portion has a protruding portion that protrudes in the radial direction so as to contact the raceway,
The protrusion is single or plural,
When there are a plurality of the projecting portions, the phase angle in the circumferential direction of at least one of the lengths between two projecting portions adjacent in the circumferential direction is larger than 180 °. Cage. The rolling bearing cage according to claim 1,
The annular portion has a cylindrical cylindrical portion,
The rolling bearing retainer, wherein the protruding portion is a protruding portion protruding in the radial direction from the outer peripheral surface of the cylindrical portion.

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