JP5804576B2 - Rolling bearing - Google Patents

Description

  The present invention relates to a rolling bearing, and more particularly to a rolling bearing applied to a spindle device of a machine tool and a high-speed motor.

  With the recent spindles of machine tools, the speed has increased due to high-efficiency machining, and the conventional gear drive and belt drive have poor transmission efficiency such as friction at the tooth meshing part and heat generation due to belt slip. The direct drive motor type with a ring and the so-called motor built-in type in which a motor is mounted inside the main shaft dominate. In the case of these high-speed main shafts, the dmn value of the bearing used for the main shaft is almost 500,000 or more. In addition, there are cases where the dmn value exceeds 1 million or more in a bearing in which the centrifugal force of the ball during high-speed rotation is suppressed by using a lightweight ceramic material (for example, silicon nitride) having a small specific gravity for the rolling element of the bearing. .

  In a cage used for such a bearing for high-speed rotation applications, as a lightweight and wear-resistant synthetic resin material cage, for example, phenol, polyamide, polyphenylene sulfide (abbreviation: PPS), polyether ether ketone ( Abbreviation: PEEK), polyimide, and the like are used, and glass fiber, carbon fiber, aramid fiber, or the like may be added as a reinforcing material.

  The cage places the rolling elements at equal intervals in the circumferential direction by pockets formed at equal intervals in the circumferential direction. As a matter of course, in order to smoothly rotate the rolling element within the pocket, it is necessary to provide an appropriate clearance (pocket clearance) between the pocket inner diameter and the rolling element. The cage is also provided with a clearance in the radial direction of the bearing between the inner and outer rings, and the radial movement amount of the cage is between the inner peripheral surface of the outer ring and the outer peripheral surface of the cage or between the outer peripheral surface of the inner ring and the inner surface of the cage. Regulated by the smaller clearance (guide clearance) between the peripheral surfaces. Further, when the rolling element is a ball and a ball guide is used, the radial movement amount of the cage is restricted to the radial clearance between the ball and the pocket as described above.

  For this reason, in a rolling bearing incorporating such a cage, the shape error of the inner ring raceway surface and the outer ring raceway surface on which the rolling element rolls in contact, the shape error of the rolling element itself, or the center between the inner ring and outer ring of the bearing Due to shaft misalignment, inclination, etc., the rolling elements are slightly delayed or advanced for each rolling element, and come into contact with the inner surface of the cage pocket. Also, the cage itself behaves irregularly between the outer and inner rings. As a result, noise and vibration called cage noise may occur.

  For example, as in the ball bearing 100 shown in FIG. 15A, the direction of the frictional force between the ball 102 and the pocket surface changes when the cage 101 swings around the guide clearance. For this reason, as shown in FIG. 15B, the cage 101 may behave irregularly such that the central axis of the cage 101 draws several circles, and cage noise may be generated.

  Also, grease lubrication is usually used for rolling bearings. Grease lubrication is very simple and widely used as the most common lubrication method because it can be used for a long time simply by pre-filling a predetermined amount of grease when mounting the bearing.

  In grease lubrication, after applying grease and assembling the bearing to the main shaft, a careful leveling operation is required before normal operation. This is because the grease is uniformly distributed throughout the bearing, and the grease is gradually removed from the rolling contact portion so that unnecessary resistance is not applied. As a specific leveling operation method, the engine starts rotating at a low speed and gradually increases the rotation speed while confirming that the bearing temperature is stable. If the engine speed is suddenly increased to the maximum speed without running-in, the bearing internal temperature will rise rapidly due to the stirring resistance of excess grease on the rolling surface and in the vicinity of the rolling surface. Abnormal temperature rise may cause seizure.

  Further, during these leveling operations, the amount of lubricant in each part of the bearing is in a non-uniform state, which makes the rotational behavior of the rolling element unstable. For this reason, in combination with the above-mentioned main factors such as the shape error of the inner ring raceway surface and the outer ring raceway surface, the shape error of the rolling element itself, or the misalignment and inclination of the center axis of the bearing inner ring and outer ring, the rolling element A small delay or advance is likely to occur, or it causes an irregular behavior between the outer and inner rings of the cage itself, and cage noise is likely to occur.

  Also, oil-air lubrication and spray lubrication (also referred to as oil mist lubrication), which are mainly applied to high-speed spindles, rather than grease lubrication, do not promptly discharge uneven lubrication oil or lubricated oil in the bearing. In some cases, the bearing stays in the bearing, and the amount of lubricating oil becomes non-uniform or excessive in the bearing, so that cage noise is generated for the same reason as that for grease lubrication.

  When the cage sound is generated, there is an unpleasant sensation on hearing, and the generated vibration may adversely affect the processing accuracy. This cage noise is likely to occur during a running-in operation for the reasons described above, but may occur intermittently even after running-in when high-viscosity grease or a brand with a high base oil viscosity of grease is used. (Especially in winter, when the temperature of the grease decreases, the viscosity of the grease increases and its fluidity deteriorates.) The presence or absence of cage noise is confirmed by trial operation of the spindle at machine tool manufacturers and machine tool manufacturers, but it may occur again at the end user after shipment, which is very troublesome abnormal noise. .

  Further, when the cage sound is generated at a high speed rotation, the sound level and the vibration level are very high as compared with the low speed rotation, which is likely to cause a quality problem.

  On the other hand, measures to suppress the cage noise include countermeasures such as time-consuming operation, selecting soft grease with low viscosity, changing the contact position between the ball and pocket and the shape of the contact part. ing. As another example of measures against the cage sound, there is a device that intentionally provides unbalance by providing a recess in a part of the cage (see, for example, Patent Document 1). In Patent Document 1, as shown in FIG. 16, a concave portion 111 is provided in a wedge shape at a part of the pocket column portion at both ring portions of the retainer 110 and in the axial phase, or as shown in FIG. By providing a through hole 121 in the radial direction from the outer diameter surface to the inner diameter surface of the cage 120, or by providing a recess without penetrating the cage 120, irregular vibration of the cage is suppressed by giving a whirl by unbalance. ing.

  Further, a device has been devised in which a concave portion is provided in a part of the cage to cause a weight imbalance in the circumferential direction and suppress fretting.

JP 2005-337315 A JP-A-9-292008

  By the way, in order to suppress cage noise, countermeasures such as time-consuming operation, selecting soft grease with low viscosity, changing the contact position between the ball and pocket and the shape of the contact part, etc. Depending on the shape of the cage, the measures and effects were not uniform and not always effective.

  In addition, when the concave portion 111 as shown in FIG. 16 is formed, stress concentration occurs in the concave portion 111, and the force applied to the cage 110 during rotation (acting on the ring portion by the interference force / centrifugal force between the ball and the pocket). Cracks may be generated or damaged from the recesses. In addition, in the through hole 121 as shown in FIG. 17, the guide surface and the hole wrap in the inner ring guide or the outer ring guide, so that the edge portion of the hole 121 interferes with the other guide member (inner ring or outer ring). In some cases, the cage 120 may have unstable behavior, wear or breakage of the edge portion of the hole 121, or may have problems such as large torque and large heat generation. In particular, when a rolling bearing is used at a high speed rotation such as a main shaft or a motor shaft of a machine tool, the above-mentioned problems are likely to occur.

  Also, when machining recesses (especially in the case of holes that do not penetrate from the inner diameter side to the outer diameter side), when drilling is difficult, or when manufacturing by injection molding, the mold of the recess part However, there is a problem that mold release (it is difficult to remove an injection-molded product from the mold) and the structure of the mold becomes complicated.

In addition, regarding the formula that defines the amount of eccentricity from the geometric center to the center of mass described in Patent Document 1, the coefficient α is merely described as a coefficient of an allowable centrifugal force, and specific numerical values are disclosed. Absent. In addition, the coefficient α is considered to vary depending on the size of the bearing, the type of lubricant, the cage material, and the like, and it is very difficult to carry out concretely.
Furthermore, Patent Document 1 obtains the locus of the center of mass by numerical simulation analysis, and clarifies the difference in the magnitude of vibration of the cage, but if the vibration value is actually lowered, the generation of the cage noise is eliminated. Whether it can be done is not disclosed in the verification experiment results.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to deliberately give an appropriate unbalance amount to the cage and to give the cage an eccentric motion in a certain direction. An object of the present invention is to provide a rolling bearing that suppresses regular behavior and prevents cage noise.

The above object of the present invention can be achieved by the following constitution.
(1) An outer ring, an inner ring, a plurality of rolling elements that are freely rollable between the outer ring and the inner ring, and a plurality of rolling elements that are formed at predetermined intervals in the circumferential direction, and hold the plurality of rolling elements, respectively. A cage having a plurality of pockets, and a rolling bearing in which the guidance method of the cage is an outer ring guide,
The inner diameter of the rolling bearing is 30 mm or more and 150 mm or less,
The cages are arranged side by side in the axial direction, and are arranged at predetermined intervals in the circumferential direction so that at least one outer peripheral surface connects between the pair of ring portions constituting the guide surface and the pair of ring portions. A plurality of pillars, and
In part of the circumference direction of the outer peripheral surface of the pair of ring portions, and consists of a portion of the radial portion and axially outer end face in the axial direction of the outer peripheral surface of the pair of ring portions, at least one of A recess is formed continuously across the plurality of pockets,
The rolling bearing is characterized in that the cage is formed asymmetrically so as to have an unbalance amount of 0.8 g · cm to 4 g · cm.
(2) The rolling bearing according to (1), wherein outer peripheral surfaces of the pair of ring portions have a larger diameter than a radially outer surface of the column portion.
The outer ring guide method of the present invention is a structure in which the cage is positioned and guided in the radial direction up to the clearance between the outer peripheral surface of the cage and the inner peripheral surface of the outer ring. In ball bearings where the rolling elements are balls, the cage is positioned in the radial direction until the radial clearance between the ball and the contact point (convex part) inside the cage pocket when the cage is moved in the radial direction. Means a guided structure.

According to the rolling bearing of the present invention, the inner diameter is 30 mm or more and 150 mm or less, and the cage is formed asymmetrically so that the unbalance amount is 0.8 g · cm or more and 4 g · cm or less. By deliberately giving an appropriate unbalance amount to the cage and giving the cage eccentric motion in a certain direction, irregular behavior of the cage is suppressed and cage noise is prevented.
In particular, at least one is a part of the circumferential direction of the outer peripheral surface of the pair of ring portions constituting the guide surface, and a part of the outer peripheral surface of the pair of ring portions in the axial direction and the radial direction of the axial outer end surface. In part, since at least one recess is continuously formed across the plurality of pockets, the unbalanced load can be concentrated in one phase.

It is sectional drawing which shows the rolling bearing which concerns on the 1st reference example of this invention. It is a perspective view of the holder | retainer of the rolling bearing of FIG. (A) is the side view of the holder | retainer of FIG. 2, (b) is the III section enlarged view of (a), (c) is the partial top view seen from III 'of (a). (A) is a side view of a cage according to a second reference example of the present invention, (b) is an enlarged view of the IV part of (a), and (c) is a portion viewed from IV ′ of (a). It is a top view. (A) is a side view of a cage according to a third reference example of the present invention, (b) is an enlarged view of a V part of (a), and (c) is a part viewed from V ′ of (a). It is a top view. (A) is a side view of the retainer according to the first embodiment of the present invention, (b) is an enlarged view of the VI part of (a), and (c) is a portion viewed from VI ′ of (a). It is a top view, (d) is sectional drawing along the VI "-VI" line of (a). It is sectional drawing which shows the rolling bearing which concerns on the 4th reference example of this invention. (A) is a side view of the cage of FIG. 7, (b) is an enlarged view of the VIII portion of (a), and (c) is a partial top view as seen from VIII ′ of (a). It is sectional drawing which shows the rolling bearing which concerns on the modification of the 4th reference example of this invention. (A) is a side view of a cage according to a fifth reference example of the present invention, (b) is an enlarged view of the X part of (a), and (c) is a portion viewed from X ′ of (a). It is a top view, (d) is an X ″ portion enlarged view of (a), and (e) is a partial bottom view seen from X ″ of (a). It is sectional drawing which shows the rolling bearing which concerns on the modification of the 5th reference example of this invention. It is sectional drawing which shows the rolling bearing which concerns on the 6th reference example of this invention. (A) is a side view of a cage according to a sixth reference example of the present invention, (b) is an enlarged view of the XIII part of (a), and (c) is a portion viewed from XIII ′ of (a). It is a top view. It is sectional drawing which shows the testing apparatus of this invention. (A) is a figure which shows the change of the direction of the frictional force by the whirling of a cage | basket, (b) is a figure which shows the whirling of the center axis | shaft of a cage | basket when the cage | basket sound is confirmed. is there. It is a perspective view which shows the conventional holder | retainer. It is a perspective view which shows the other conventional holder | retainer.

Hereinafter, each reference example of the present invention and the rolling bearing according to the first embodiment will be described in detail based on the drawings.

(First Reference Example )
As shown in FIGS. 1 to 3, a cylindrical roller bearing 1 according to a first reference example of the present invention includes an outer ring 2 having an outer ring raceway surface 2a on an inner peripheral surface and an inner ring 3 having an inner ring raceway surface 3a on an outer peripheral surface. And a plurality of rollers (rolling elements) 4 that are arranged to freely roll between the outer ring raceway surface 2a and the inner ring raceway surface 3a, and a plurality of rollers that are formed at predetermined intervals in the circumferential direction and hold the plurality of rollers 4 respectively. And a cage 10 having a pocket 11.

  The cage 10 has a pair of ring portions 12 arranged side by side in the axial direction, and a plurality of column portions 13 arranged at predetermined intervals in the circumferential direction so as to connect both the ring portions 12. The pocket 11 is constituted by the column portion 13 adjacent to the pair of rings 12. Moreover, the axial intermediate part of the both sides in the circumferential direction of the column part 13 has a side surface continuous from the circumferential side surface of the column part 13, and a roller stopper 14 for securely holding the cylindrical roller 4 is provided in the column. It protrudes from the radially outer surface of the portion 13. The cage 10 is an outer ring guide system in which outer peripheral surfaces 12a of both ring portions 12 having a diameter larger than the radially outer surface of the column portion 13 are guided by the outer ring raceway surface 2a.

In addition, at least one recess 15 (three in each ring portion 12 in this reference example ) is provided in the axial direction so as to give unbalance to a part of the outer circumferential surface 12a of both ring portions 12 in the circumferential direction. The inner surface of the pocket portion 11 and the outer end surface in the axial direction of the ring portion 12 are connected on the outer peripheral surface side of the ring portion 12. The three concave portions 15 are formed symmetrically with respect to the circumferential intermediate portion of the pocket 11 so as to correspond to the opening positions of the three pockets 11, except for the positions of the two column portions 13 between the three pockets 11. These are formed intermittently at predetermined intervals in the circumferential direction.

  Each concave portion 15 includes an arc portion 16 having a uniform curvature that makes the ring portion 12 thin, and a rising portion 17 having a large curvature radius that continues from the arc portion 16 to the outer peripheral surface 12 a of the ring portion 12. And the circumferential direction position of the boundary part 18 of the circular arc part 16 and the rising part 17 is pocket 11 more than the circumferential direction position of the root part 13a of the column part 13 so that it may not overlap with the column part 13 seeing from the axial direction. Is formed closer to the middle position C in the circumferential direction. In other words, the root portion 13a of the column portion 13 includes, in the circumferential direction, a boundary portion 18 between the arc portion 16 and the rising portion 17, and a boundary portion between the concave portion 15 and the outer peripheral surface 12a of the ring portion 12 (the rising portion 17 and the ring portion 12). (Between the outer peripheral surface of the portion 12 and the boundary portion) 19. Thereby, a sudden change in the cross-sectional area is avoided, stress concentration at the root portion 13a of the column portion 13 is prevented, and the strength of the cage 10 is maintained. Further, by increasing the radius of curvature of the rising portion 17, stress concentration at the rising portion 17 is prevented.

Moreover, since the recessed part 15 is formed over the axial direction of the ring part 12, it becomes easy to discharge | release grease, and also can prevent the cage | basket | tork sound at the time of a run-in operation. Particularly, the sealed grease spreads over the entire bearing while adhering to the roller 4. Moreover, since the recessed part 15 is provided in the opening position of the pocket 11, the excess grease adhering to the roller 4 can be smoothly moved and discharged to the bearing end surface side. In this reference example , a narrow outer peripheral surface that is continuous with the radially outer surface of the column portion 13 is formed on the axially inner portion of the ring portion 12, but the arc portion 16 of the recess 15 is formed on the outer peripheral surface. It is recessed to a depth approximately equal to.

  Here, since the unbalance force acting on the cage during rotation is proportional to the square of the cage rotation speed as shown in Equation (1), the unbalance force increases as the rotation speed of the bearing increases, resulting in irregular behavior. It becomes possible to suppress.

Fc = meω ² Equation (1)
here,
Fc: Centrifugal force acting on the cage due to imbalance m: Eccentric mass e: Distance from the center of rotation of the eccentric mass ω: Angular velocity (2 · π · n / 60)
n: Cage rotation speed (min ⁻¹ )
When the eccentric mass is set to “kg” and the distance from the rotation center of the eccentric mass is set to “m” in SI units, the centrifugal force is calculated by N (Newton).

  In general-purpose motors and household appliance motors, the dmn value of the bearing is often 500,000 or less, so even if a considerable amount of unbalance is added, the unbalanced force causes irregular behavior between the outer and inner rings of the cage itself. Cannot overcome the random eccentric motion during rotation. However, in a machine tool, if the dmn value exceeds 500,000, or if a ceramic material (for example, silicon nitride) is used for the rolling element, there are many high-speed spindles of 1 million or more and 1.2 million or more. As the rotation is increased, the eccentric direction of the retainer 10 is fixed to the unbalanced phase during the rotation, and the irregular behavior of the retainer 10 that is more likely to cause adverse effects (sound and vibration) is reliably suppressed at high speed rotation. it can. Thereby, a cage | basket | torney sound is suppressed and the favorable acoustic characteristic and vibration characteristic of a bearing are improved.

  Accordingly, the cage 10 is provided with an appropriate unbalance so that the cage 10 is eccentrically rotated (so-called whirl motion) at a phase where the unbalance is present (that is, the normal direction is constant at the unbalance position). An appropriate unbalance amount may be set depending on the dmn value of the bearing and the weight of the bearing. In the cylindrical roller bearing 1 having an inner diameter of 30 mm or more and 150 mm or less, the unbalance amount (= eccentric mass (unit: kg) × the distance of the eccentric mass from the rotation center (unit: m)) is 0.8 g · cm. It is set to 4 g · cm or less.

  When the unbalance amount is less than 0.8 g · cm, the force from an irregular direction during rotation cannot be overcome, and the unidirectional whirl movement cannot be performed, so that vibration increases and a cage sound is generated. In addition, when the cage sound is not generated (when there is no irregular vibration and ideally whirls in one direction), not the number of circles as shown in FIG. Only one circle is displayed.

  On the other hand, when the unbalance amount exceeds 4 g · cm, the cage 10 becomes elliptical in the unbalance direction due to the centrifugal force (the cage is held by the unbalance force at the 180 ° symmetrical position with the guide portion as a fulcrum). 10 is pulled), the cage itself promotes irregular behavior between the outer and inner rings, the contact pressure with the guide surface increases, and the frictional fluctuation at the contact portion causes the irregular direction. As a result, the vibration of the cage 10 is increased.

Further, in the cylindrical roller bearing 1 of the present reference example , an outer ring guide system is adopted as a guide system for the cage 10 that imparts unbalance. If an imbalance is applied to the inner ring guide type cage, the cage will rotate eccentrically in contact with the outer circumferential surface of the inner ring, and the inner ring will have a revolving period of the cage (= revolution frequency of the cage). ) Unbalanced load is applied (see Equation (1) for the load). The revolution frequency of the cage is about 0.4 to 0.45 times the rotation speed of the inner ring. Occurs as. As a result, when the unbalance force applied to the rotating shaft increases, the NRRO component of the rotating shaft increases, resulting in uneven shape of the work surface of the workpiece, resulting in poor stitching, reduced glossiness, and reduced roundness. Arise.

  However, in the case of the outer ring guide system, the cage does not come into contact with the inner ring (= rotating shaft) on the rotating side, so that the unbalance force does not act and the NRRO component swinging motion of the shaft does not occur.

  Further, in consideration of a decrease in the lubrication characteristics of the guide surface due to an increase in the unbalance load due to an increase in the rotational speed, the cage 10 has a dmn value of 1.3 million or less for grease lubrication, and dmn for oil air and spray lubrication (oil mist lubrication). It is desirable to adopt a value of 1.8 million or less.

As described above, in the cylindrical roller bearing 1 having an inner diameter of 30 mm or more and 150 mm or less in the present reference example , the outer ring guide type cage 10 has an unbalance amount of 0.8 g · cm or more and 4 g · cm or less. Since the recess 15 is asymmetric with respect to the point, the irregular behavior of the cage 10 is obtained by intentionally giving an appropriate unbalance amount to the cage 10 and giving the cage 10 an eccentric motion in a certain direction. Can be suppressed and the cage noise can be prevented.

  Moreover, since the recessed part 15 is formed in a part of the circumferential direction of the outer peripheral surface of the ring part 12 of the cage 10, the column part 13 on which the cylindrical roller 4 comes into contact and a load acts directly in the circumferential direction is provided. It can be avoided.

Further, since the recess 15 is formed on the outer peripheral surface of the ring portion 12 in the axial direction symmetrically with respect to the intermediate portion in the circumferential direction of the pocket 11, the excess grease attached to the cylindrical roller 4 is removed from the ring portion 12. It can be smoothly moved to the axial outer end surface side and discharged. Accordingly, the cage 10 of the present reference example can provide appropriate imbalance and good grease discharge characteristics.

  Further, since the circumferential position of the boundary portion 18 of the rising portion 17 of the recess 15 is formed closer to the intermediate position in the circumferential direction of the pocket 11 than the circumferential position of the root portion 13a of the pillar portion 13, It is possible to avoid a significant change in the cross-sectional area, prevent stress concentration at the root portion 13a of the column portion 13, and maintain the strength of the cage 10.

  In addition, by applying such a cylindrical roller bearing 1 to a main spindle for a machine tool in which the dmn value of the bearing is 500,000 or more, the effect can be exhibited without reducing the rotational accuracy of the main spindle.

  In addition, the number of the recessed parts 15 can be arbitrarily set as long as a desired imbalance is given to the holder 10. Moreover, the recessed part 15 may be formed only in one ring part 12, or may be formed in zigzag form corresponding to the opening position of the pocket 11. FIG.

(Second reference example )
FIG. 4 shows a cage 10a of a cylindrical roller bearing according to a second reference example of the present invention. As in the cage 10a, the recess 15a formed in the axial direction may be formed by a single arc, and in this case as well, an appropriate imbalance and good grease discharge characteristics can be provided. it can. Further, the boundary portion 19 between the concave portion 15a and the outer peripheral surface 12a of the ring portion 12 is located closer to the pocket 11 in the circumferential direction than the root portion 13a of the column portion 13, and stress concentration at the column portion 13 is further increased. Can be prevented.
Other configurations and operations are the same as those of the first reference example .

(Third reference example )
FIG. 5 shows a cage 10b of a cylindrical roller bearing according to a third reference example of the present invention. Even when the concave portion 15b formed in the axial direction is formed by a plurality of arcs having different curvatures like the cage 10b, it is possible to provide unbalance and provide excellent grease discharge performance. Also in this case, since the boundary portion 19 between the recess 15b and the outer peripheral surface 12a of the ring portion 12 does not interfere with the column portion 13, stress concentration at the column portion 13 can be further prevented.
Other configurations and operations are the same as those of the first reference example .

(First Embodiment)
FIG. 6 shows a cage 10c for a cylindrical roller bearing according to the first embodiment of the present invention. In this cage 10c, a pair of recesses 15c cuts out a boundary portion between the axially outer end surface and the outer peripheral surface of both ring portions 12, and a plurality of pockets are formed in a part of the circumferential direction of both ring portions 12. 11 is formed continuously. Further, the angle θ for forming the recess 15c is set within 90 ° in order to concentrate the unbalance load in one direction. Moreover, it is preferable that the rising part 17 of such a recessed part 15c becomes a position which does not overlap with the pillar part 13 in the circumferential direction, and it is better that the radius of curvature is large in consideration of stress concentration.

In addition, since the axial guide width of the outer peripheral surface 12a of the ring portion 12 serving as the guide surface of the cage 10c is narrowed by the recess 15c, the grease discharge characteristics are better than when the recess 15c is not provided.
Other configurations and operations are the same as those of the first reference example .

( 4th reference example )
FIG. 7 shows an angular ball bearing according to a fourth reference example of the present invention. The angular ball bearing 30 has a contact angle α between the outer ring 32 having the outer ring raceway surface 32a on the inner circumferential surface, the inner ring 33 having the inner ring raceway surface 33a on the outer circumferential surface, and the outer ring raceway surface 32a and the inner ring raceway surface 33a. A plurality of balls (rolling elements) 34 that are arranged to be freely rollable, and a cage 40 that is formed at a predetermined interval in the circumferential direction and has a plurality of pockets 41 that respectively hold the plurality of balls 34.

As shown in FIG. 8, the cage 40 includes a pair of ring portions 42 arranged side by side in the axial direction, and a plurality of cage portions 40 arranged at predetermined intervals in the circumferential direction so as to connect the ring portions 42 to each other. The cylindrical pocket 41 is defined by the column portion 43 adjacent to the pair of ring portions 42. The retainer 40 is an outer ring in which an outer peripheral surface 42a of one ring portion 42 is guided by an inner peripheral surface 32b of the counter-bore of the outer ring 32 out of both ring portions 42 having a larger diameter than the outer surface in the radial direction of the column portion 43. It is a guidance method.

Also in this reference example , at least one concave portion 45 (in this reference example , each ring portion 12 has 3 in order to give an imbalance to a part of the outer circumferential surface 42a of both ring portions 42 in the circumferential direction. Are formed in the axial direction, and the inner surface of the pocket 41 and the outer end surface in the axial direction of the ring portion 42 are connected on the outer peripheral surface side of the ring portion 42. The three concave portions 45 are formed symmetrically with respect to the circumferential middle portion C of the pocket 41 so as to correspond to the opening positions of the three pockets 41, except for the positions of the two column portions 43 between the three pockets 41. Thus, they are formed intermittently at predetermined intervals in the circumferential direction.

  Each concave portion 45 includes an arc portion 45 a having a uniform curvature that makes the ring portion 12 thin, and a curved rising portion 45 b that continues from the arc portion 45 a to the outer peripheral surface of the ring portion 12. In addition, the circumferential width of the recess 45 is set to be narrower than the circumferential width of the corresponding pocket 41, and a sudden change in the cross-sectional area is avoided to prevent stress concentration in the column portion 13. Moreover, since the recessed part 45 is formed over the axial direction of the ring part 42, the discharge property of grease becomes favorable.

Also in this reference example , in the angular ball bearing 30 having an inner diameter of 30 mm or more and 150 mm or less and provided with the outer ring guide type retainer 40, the unbalance amount is 0.8 g · cm or more and 4 g · cm or less. Thus, by setting with the recessed part 45, an appropriate imbalance can be provided like the 1st reference example .

In this reference example , the outer ring guide type retainer 40 has been described. However, as shown in FIG. 9, a ball guide type retainer 40 a having a spherical pocket 41 may be applied. Even when the ball guide type cage 40a is unbalanced, a whirl motion is given by contact between the specific pocket 41 in the unbalance direction and the ball 34, and the cage is rotated on the rotating side as in the inner ring guide type. Since the inner ring (= rotating shaft) is not touched, the unbalance force does not act, the NRRO component swinging motion of the shaft does not occur, and the same effect as the outer ring guide type retainer 40 can be obtained. it can.

  However, since the ball guide type retainer 40a has a small contact area between the ball 34 and the pocket 41, the contact surface pressure is likely to increase, and there is no problem at a high speed of about 500,000 to 1.3 million dmn value. Since the problem of wear of the sliding portion is a concern at higher rotation speeds, the outer ring guide method is preferable. In the case of the outer ring guide method, the outer peripheral surface of the cage 40 and the inner peripheral surface of the outer ring 32 are in contact with each other with a predetermined area, so that the contact surface pressure is small and the sliding portion is not easily worn.

( 5th reference example )
FIG. 10 shows an angular ball bearing retainer 40b according to a fifth reference example of the present invention. In this retainer 40b, at least one convex portion 46 (the main portion 46) is connected to the ring portion 42 of the column portion 43 at a phase substantially opposite to the concave portion 45 with respect to the retainer 40 of the fourth reference example. In the reference example , a total of 8) is provided on both axial sides of the four pillar portions 43.

Thereby, even if it is a case where a required imbalance amount cannot be added only by the recessed part 45, the required unbalance amount can be ensured by providing the convex part 46. In addition, although the convex part 46 may be formed in the internal peripheral surface of the column part 43, it considers that the mold release at the time of injection molding is easy, and is formed in the outer peripheral surface of the column part 43. Is preferred.
Moreover, when forming the convex part 46 like this reference example , unbalance can be provided without worrying about the strength fall of the holder | retainer 40b by stress concentration.
Other configurations and operations are the same as those in the fourth reference example .

  11, the pair of convex portions 46 formed on the outer peripheral surface of the column portion 43 are close to the intermediate portion in the axial direction of the column portion 43 (in FIG. 11, the cross-sectional portion of the ball 34). It is possible to reliably avoid contact with the outer ring raceway surface 32a of the column portion 43 during rotation. Furthermore, in the angular ball bearing 30b having a counter bore, the retainer 40 can be easily inserted from the axial end surface on the counter bore side without the convex portion 46 interfering with the inner peripheral surface of the outer ring 32.

( Sixth reference example )
FIG. 12 shows an angular ball bearing 30c according to a sixth reference example of the present invention. The ball guide type cage 40c used for the angular ball bearing 30c has a convex portion 46a on a part of the outer circumferential surface 42a of one ring portion 42 located on the counter bore side in the circumferential direction. . Further, the outer peripheral surfaces of the ring portion 42 and the column portion 43 have a continuous uniform outer diameter excluding the convex portion 46a. Thereby, imbalance can be given by providing the convex part 46a in the outer peripheral surface of the ring part 42 by the side of a counterbore.
Other configurations and operations are the same as those of the fourth reference example .

The present invention is not limited to the above reference examples and the first embodiment, and can be changed, improved, and the like as appropriate. In addition, the configurations of each of the reference examples and the first embodiment can be combined and applied within a feasible range.

  In the rolling bearing of the present invention, any lubrication system such as oil-air lubrication or spray lubrication (oil mist) may be used in addition to grease lubrication, but a lubricant bearing compared to oil-air lubrication or spray lubrication (oil mist). Grease lubrication, which tends to cause unevenness inside, can be more effective.

Moreover, although the said each reference example and 1st Embodiment demonstrated the cylindrical roller bearing and the angular ball bearing, it is applicable also to other rolling bearings, such as a deep groove ball bearing and a tapered roller bearing.
Furthermore, the cage is not limited to a cage-type cage having a pair of ring portions, and may have other shapes such as a crown type cage.
Moreover, considering the use at high speed rotation, the cage material is preferably a synthetic resin that is lighter than metal and excellent in wear resistance, such as phenol, polyamide, PPS, PEEK, and polyimide. Further, reinforcing agents such as glass fiber, carbon fiber and aramid fiber may be added.

  Here, using a single row cylindrical roller bearing 1 as shown in FIG. 1, the relationship between the unbalance amount of the cage 10 and the cage sound was tested. FIG. 14 is a cross-sectional view of an evaluation test apparatus (balance measuring instrument EVD-3.1, manufactured by Shimadzu Corporation) 50 used in this test. A cylindrical roller bearing 1 as a test bearing is In addition, a pair of angular contact ball bearings 53 that support one end of the rotating shaft 52 are incorporated so as to support the other end of the rotating shaft 52. The test conditions of this test are shown below, and the test results are shown in Table 1.

Test bearing: Single-row cylindrical roller bearing: N1011 (inner diameter: 55 mm, outer diameter: 90 mm, width: 18 mm, cage material: synthetic resin containing reinforcing fiber agent (carbon fiber-added PEEK resin)
・ Unbalance specification: According to the first reference example・ Test rotation speed: 12,000 min ^-1 (maximum)
・ Lubrication method: Grease lubrication (Base oil viscosity: 105 cst)

As a result of Table 1, when the unbalance amount is small, the cage behaves irregularly and a cage noise is generated. However, when an appropriate imbalance is applied, the generation of the cage noise can be suppressed.
On the other hand, when the unbalance amount was too large as in the test product A, the generation of cage noise was recognized. This is because the cage is deformed due to the centrifugal force due to unbalance, or the contact pressure on the guide surface increases and the sliding friction at this part increases. This is thought to be due to the behavior.
In the test product G, the cage sound disappeared at 12,000 min ⁻¹ because the centrifugal force overcomes the irregular force acting on the cage, and the whirl motion at a constant phase compared to the low speed rotation. This is thought to be due to the fact that
It can be seen from Table 1 that the amount of unbalance that can reliably suppress the cage noise is 0.8 g · cm or more and 4 g · cm or less.

1 Cylindrical roller bearing (rolling bearing)
10, 10a, 10b, 10c, 40, 40a, 40b, 40c Cage 11, 41 Pocket 12, 42 Ring part 13, 43 Pillar part 15, 15a, 15b, 15c, 45 Concave part 46, 46a Convex part 30, 30a, 30b, 30c angular contact ball bearings (rolling bearings)
α Contact angle

Claims (2)

An outer ring, an inner ring, a plurality of rolling elements that are freely rollable between the outer ring and the inner ring, and a plurality of pockets that are formed at predetermined intervals in the circumferential direction and hold the plurality of rolling elements, respectively. A rolling bearing in which the guide method of the cage is an outer ring guide,
The inner diameter of the rolling bearing is 30 mm or more and 150 mm or less,
The cages are arranged side by side in the axial direction, and are arranged at predetermined intervals in the circumferential direction so that at least one outer peripheral surface connects between the pair of ring portions constituting the guide surface and the pair of ring portions. A plurality of pillars, and
In part of the circumference direction of the outer peripheral surface of the pair of ring portions, and consists of a portion of the radial portion and axially outer end face in the axial direction of the outer peripheral surface of the pair of ring portions, at least one of A recess is formed continuously across the plurality of pockets,
The rolling bearing is characterized in that the cage is formed asymmetrically so as to have an unbalance amount of 0.8 g · cm to 4 g · cm.   2. The rolling bearing according to claim 1, wherein outer peripheral surfaces of the pair of ring portions have a larger diameter than a radially outer surface of the column portion.