JP4855181B2 - Roller bearing - Google Patents

Description

  The present invention relates to a roller bearing in which a spacer is interposed between rolling elements instead of a cage.

  Patent Document 1 discloses a roller bearing in which a spacer is interposed between rollers instead of a cage. This type of roller bearing can incorporate more rollers in the bearing and can exhibit a high load capacity.

  As shown in FIG. 4, the surface of the spacer 8 facing the rolling surface of the roller 6 has a concave shape for receiving the roller rolling surface, and the spacer 8 is a race (the outer ring 2 or the inner ring 4, here the outer ring 2). ) Can stabilize the behavior of the spacer during driving. However, since the spacer 8 has a concave shape, depending on the shape of the spacer (the relationship between the concave shape and the clearance between the bearing rings), the spacer 8 has an outer ring collar as shown by a dark arrow in FIG. A force in the bearing radial direction is received from the adjacent rollers 6 toward the inner peripheral surface. As a result, the spacer rotates with the spacer pressed against the race, and especially when the spacer is pressed against the non-rotating wheel, the spacer acts as a brake (brake), so seizure occurs when the rotational speed is high. May occur.

Therefore, in Patent Document 1, the contact surface of the spacer with the roller rolling surface is a flat surface orthogonal to the circumferential direction of the bearing so that no radial force acts on the spacer from the roller. It is described to do. However, the spacer posture is not always constant, and the orthogonal state to the bearing circumferential direction may be lost. The posture is corrected by the adjacent rollers, but under operating conditions such as forward / reverse rotation of the bearing or rapid acceleration / deceleration, the posture of the spacer is greatly disturbed, so a radial force acts on the spacer each time. There is a risk of causing heat generation on the guide surface and abnormal wear of the spacer.
Japanese Patent No. 3549530

  A main object of the present invention is to avoid a state in which a spacer is pressed against an outer ring or an inner ring by adjacent rollers during the operation of the roller bearing in which a spacer is interposed between rollers, and in the guide surface of the spacer. It is to reduce heat generation and wear.

The roller bearing of the present invention has an outer ring, an inner ring, a plurality of rollers, and a spacer interposed between adjacent rollers, and the surface of the spacer facing the roller rolling surface straddles the pitch circle of the roller. When the spacer has an extended part facing the bearing ring, the roller diameter is Dw, the number of rollers is Z, and the circumferential clearance is S, 0.001 × Dw × Z ≦ S ≦ 0.01 × Dw × Z is satisfied, the diameter of the collar outer diameter surface or the collar inner diameter surface of the bearing ring is d1, the collar outer diameter surface of the extension portion and the bearing ring or when the gap between the collar inner surface and the Sr, by setting the relationship 0.005 × Dw <Sr <0.1 × d1 0.4, when sandwiched between seat in rollers adjacent spacer of Ri Sukimagaa between the bearing ring and the extension portion, and is characterized in that the spacer a roller guide. When the spacer is sandwiched between rollers on the raceway surface, the radial position of the spacer is determined with the concave bottom as a contact position. At this time, by setting the clearance between the spacer and the raceway surface, it is possible to avoid a state in which the spacer is pressed against the raceway by adjacent rollers. That is, the spacers by the setting is the guide basically rollers, only the spacer situated in the circumferential clearance is released from the constraint of the rollers adjacent to the outer ring in the rotational speed is high if low if The specifications are such that they are guided by rollers or inner rings. Since the radial force other than its own weight and centrifugal force does not act on the released spacer, heat generation and wear on the guide surface of the spacer can be reduced.
Further, when the roller diameter is Dw, the number of rollers is Z, and the clearance in the circumferential direction is S, a configuration that satisfies the relationship of 0.001 × Dw × Z ≦ S ≦ 0.01 × Dw × Z is adopted. As a result, the behavior of the spacer can be stabilized and vibration can be suppressed while avoiding the disappearance of the circumferential clearance due to the thermal expansion of the spacer and the roller during the operation of the bearing.

Outer ring inner diametric surface and opposite surface of the front Symbol expansion unit, a small radius of curvature of the convex shape than the radius of curvature of the outer ring inner diametric surface, the surface facing the inner ring outer diametric surface of the front Symbol expansion unit from the inner ring outer diametric surface of the radius of curvature Alternatively, a convex shape having a large curvature radius may be used. Here, when the convex shape is formed by two planes, the radius of curvature indicates the radius of curvature of an arc connecting the intersection of the two planes and the end point of the writing plane. By adopting such a configuration, a so-called “wedge film effect” (an effect in which a fluid is drawn into a wedge-shaped clearance narrowing in the direction of motion by viscosity to generate pressure, that is, a load capacity) is obtained. Heat generation and wear on the seat guide surface can be reduced. Here, the “outer ring inner diameter surface” refers to the inner diameter surface of the collar of the outer ring that can support and guide the extended portion of the spacer in the radial direction. Similarly, the “outer diameter surface of the inner ring” refers to a collar outer diameter surface of the inner ring that can support and guide the spacer in the radial direction.

Dw an outer diameter of the roller, the diameter of the outer ring inner diametric surface d1, when the predetermined gap was Sr, 0.005 × Dw <relationship Sr <01 × d1 ^0.4 is satisfied, Or, the rollers the outer diameter of Dw, the diameter of the inner ring outer diametric surface d1, when the predetermined gap was Sr, 0.005 × relationship Dw <Sr <0.1 × d1 ^0.4 adopts the configuration you satisfied Thus, the clearance Sr can be set not to be crushed during operation, and the behavior of the spacer can be stabilized. That is, the lower limit (0.005 × Dw) allows thermal expansion of the spacer during operation, and the upper limit (0.1 × d1 ^0.4 ) is a setting value for reducing the radial displacement of the spacer. In both cases, the clearances confirmed by the operation test are quantified.

  The spacer released from the restraint of the adjacent rollers becomes free in the circumferential clearance, and the behavior becomes unstable. When the spacer passes through the circumferential clearance, the spacer is again restrained by the rollers. At that time, the spacer is suddenly returned to the roller guide state according to the uneven shape, and vibration is generated. That is, if the clearance Sr is large, the amount of displacement when the spacer is returned to the roller guide state becomes large, so that the vibration inevitably increases.

  According to the present invention, in a roller bearing in which a spacer is interposed between rollers, a state in which the spacer is pressed against an outer ring or an inner ring by adjacent rollers is avoided, and operating conditions such as forward / reverse rotation and rapid acceleration / deceleration of the bearing are avoided. In this case, it is possible to provide a roller bearing in which vibration is suppressed by reducing heat generation and wear on the guide surface of the spacer and further stabilizing the behavior of the spacer.

  Embodiments of the present invention will be described below with reference to the drawings.

  The embodiment shown in FIG. 1 is an example applied to a cylindrical roller bearing and includes an outer ring 12, an inner ring 14, a cylindrical roller 16, and a spacer 18. This cylindrical roller bearing is of the NJ type, the outer ring 12 has a collar 12a on both sides of the raceway, and the inner ring 14 has a collar 14a on one side of the raceway. The cylindrical roller 16 rolls on the raceway surface of the outer ring 12 and the raceway surface of the inner ring 14 on its rolling surface 16a. A spacer 18 is interposed between the adjacent cylindrical rollers 16.

  At both ends of the spacer 18, extended portions 18 a having surfaces facing the end surface 16 b of the cylindrical roller 16 are formed. Here, the outer peripheral surface (the surface facing the radially outer side in a state of being incorporated in the bearing) 18c of the expansion portion 18a is a partial cylindrical surface, in other words, a convex curved surface. During the rotation of the bearing, the extended portion 18a of the spacer 18 is guided by the inner peripheral surface of the collar 12a of the outer ring 12. In this sense, the outer peripheral surface 18c of the extended portion 18a is also referred to as a guide surface. By causing the outer ring 12 to guide the spacer 18, the behavior of the spacer 18 is stabilized. That is, by supporting the outer peripheral surface 18c of the extended portion 18a of the spacer 18 with the inner peripheral surface of the collar 12a of the outer ring 12, the movement of the spacer 18 in the radial direction is restricted and the behavior is stabilized.

  The cross-sectional shape of a surface (hereinafter also referred to as a roller contact surface) 18b of the spacer 18 that contacts the cylindrical roller 16 has a radius of curvature slightly larger than the radius of curvature of the rolling surface 16a of the roller 16, as shown in FIG. It is a concave arc. The roller contact surface 18b extends over the roller pitch circle indicated by the alternate long and short dash line, that is, extends from the inner diameter side to the outer diameter side of the roller pitch circle. Therefore, the movement of the spacer 18 in the bearing radial direction is restricted by the rolling surface 16a of the roller 16.

If the material of the spacer 18 is 66 nylon (natural) and applied to NJ2324E (φ120 × φ260 × 86), the circumferential clearance S on the pitch circle of the roller 16 is 1.5 mm. Expressed as S = 0.026 × Dw × Z. The minimum thickness of the spacer 18 is 1.8 mm. At this time, even if the temperature of the bearing rises by 100 ° C., the total thermal expansion of the roller 16 and the spacer 18 is about 1 mm, and the circumferential clearance S (see FIG. 3) is not crushed. Can withstand use under temperature conditions. Incidentally, the linear expansion coefficient of the cylindrical roller (bearing steel) is 12.5 × 10 ⁻⁶ (° C.), and the linear expansion coefficient of the spacer (66 nylon (N)) is 9 × 10 ⁻⁵ (° C.).

  An outer peripheral surface (guide surface) 18c of the extended portion 18a faces the inner peripheral surface of the collar 12a of the outer ring 12. As shown in FIG. 2, a slight clearance Sr is formed between the spacer 18 constrained by the adjacent rollers 16 and the inner peripheral surface of the collar 12 a of the outer ring 12. It is not pressed against the inner peripheral surface of the collar 12a. That is, as described above, the movement of the spacer 18 in the radial direction of the bearing is restricted by the rolling surface 16a of the roller 16, and only the spacer 18 located in the circumferential clearance S (see FIG. 3) is adjacent. When it is released from the restraint of the mating rollers 16 and the rotational speed is high, it is guided to the inner peripheral surface of the collar 12a of the outer ring 12.

  In addition to the role which restrict | limits the motion of the spacer 18 in the axial direction of a bearing, the expansion part 18 also plays the role which expands the area of the guide surface 18c.

  Further, the surface of the spacer 18 facing the inner peripheral surface of the collar 12a of the outer ring 12, that is, the guide surface 18c, is a convex curved surface having a curvature radius R1 smaller than the curvature radius R2 of the inner peripheral surface of the collar 12a of the outer ring 12. Thus, a wedge film effect is generated on the guide surface 18c, and heat generation and wear on the guide surface 18c of the spacer 18 can be reduced.

  Furthermore, by making the guide surface 18c a convex curved surface, edge contact on the guide surface 18c can be avoided even if the behavior of the spacer 18 is disturbed. In addition, it is desirable to provide chamfering at the edge of the extended portion 18 facing the bearing circumferential direction.

In order to verify the temperature rise countermeasure effect according to the present invention, a temperature rise comparison test was performed for the example and the comparative example (a shape corresponding to that described in Patent Document 1). The base bearing of the test bearing is the cylindrical roller bearing NJ2324E (φ120 × φ260 × 86, roller specifications: φ38 × 62, 15 pieces) shown in FIG. 1. FIG. 5 shows the configuration of the embodiment shown in FIG. Shows the configuration of the comparative example. In addition, both differ only in the shape of the surface which faces the roller rolling surface of a spacer, and others are the same.

  As shown in FIG. 5, in the embodiment, the surface facing the roller rolling surface of the spacer 18 is formed as a concave curved surface extending across the pitch circle of the roller 16, and the curvature radius thereof is 21mm is slightly larger than 19mm of the moving surface. Here, when the spacer 18 is sandwiched between the rollers 16 on the outer ring raceway surface, the bearing radial direction position of the spacer 18 is determined with the bottom of the concave curved surface as a contact position, and the space between the spacer 18 and the inner diameter surface of the collar of the outer ring 12 is determined. There is a clearance Sr of about 0.3 mm between them. That is, by this setting, the spacer 18 basically serves as a roller guide, and only the spacer 18 located in the circumferential clearance is released from the restraint of the adjacent roller 16, and when the rotational speed is high, the collar of the outer ring 12 is released. If it is low on the inner diameter surface, it is guided to the roller 16.

  As shown in FIG. 6, in the comparative example, the surface of the spacer facing the roller rolling surface is formed as a flat surface orthogonal to the circumferential direction of the bearing. That is, as long as the orthogonal state is maintained, no radial force acts on the spacer from the roller, the spacer has a degree of freedom in the radial direction, and when the rotational speed is high, the centrifugal force All spacers are guided to the inner diameter surface of the outer ring by the force.

  A radial load of 98 kN was applied to the test bearings of the example and the comparative example, the inner ring rotational speed was stepped up to a maximum of 3500 r / min, and the temperature increase of the outer ring was measured. The results are shown in FIG. FIG. 7 shows the rotation speed (r / min) of the inner ring on the horizontal axis and the temperature rise (° C.) of the outer ring on the vertical axis. The solid line represents the measured value of the example, and the broken line represents the measured value of the comparative example. Represents. The temperature rise of the examples was lower than that of the comparative examples throughout, and as shown in Table 1, a maximum temperature reduction effect of 13 ° C. was observed.

Broken perspective view of a cylindrical roller bearing showing an embodiment of the present invention Partial enlarged side view of the bearing of FIG. Schematic cross section of cylindrical roller bearing Partially enlarged side view of cylindrical roller bearing showing conventional technology (A) is a partially enlarged side view of a test bearing (Example), (B) is an enlarged view of a spacer. (A) is a partially enlarged side view of a test bearing (comparative example), (B) is an enlarged view of a spacer. Graph showing the relationship between rotational speed and outer ring temperature rise

Explanation of symbols

12 outer ring 12a collar 14 inner ring 14a collar 16 cylindrical roller 16a rolling surface 16b end face 18 spacer 18a expansion portion 18b roller contact surface 18c guide surface (outer circumferential surface of expansion portion)

Claims (1)

It has an outer ring, an inner ring, a plurality of rollers, and a spacer interposed between adjacent rollers, and the surface facing the roller rolling surface of the spacer is a concave shape extending across the pitch circle of the rollers. And the spacer has an extended part facing one of the races, the roller diameter is Dw, the number of rollers is Z, and the circumferential clearance is S, 0.001 × Dw × Z ≦ S ≦ 0.01 × Dw × Z is established, the diameter of the collar outer diameter surface or the collar inner diameter surface of the bearing ring is d1, and the extension portion and the collar ring outer collar surface or the collar inner diameter surface when the gap was Sr, by setting 0.005 × relationship ^{Dw <Sr <0.1 × d1 0.4} , when sandwiched between seat in rollers adjacent the raceway and the extension of the spacer Sukimagaa is, a roller bearing, which was between seat the roller guide between.

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