JP5012438B2 - Needle roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a needle roller bearing capable of efficiently holding lubricating oil on a rolling surface by a limited lubricating oil quantity, without impairing retentivity to a needle-like roller. <P>SOLUTION: This needle roller bearing 10 is composed of a pair of annular parts 13 and a plurality of column parts 14 connecting the annular parts 13, and has a cage 11 forming a plurality of pockets 15 and a plurality of needle-like rollers 12 rollingly held by the pockets 15, and is formed by arranging a narrow width part 17 narrowing in width in the peripheral direction in the middle of the column parts 14. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a needle roller bearing used for supporting planetary gears in planetary gear mechanisms and the like in industrial fields such as automobiles, motorcycles, aircraft, railways, electricity / information, and steel.

  In the planetary gear mechanism, a plurality of planetary gears are assembled to pinion shafts supported by a carrier via needle roller bearings, and the planetary gears include ring gear internal teeth, sun gear external teeth, It is configured to be engaged with each other.

  Here, in the planetary gear mechanism used in the automatic transmission for automobiles, the planetary gear rotates and revolves with the carrier, so that there is a dislike that the lubricating oil is not sufficiently distributed. .

  In recent years, miniaturization has been demanded in order to improve fuel efficiency in automobiles, and as a result, the use conditions of the planetary gear mechanism as a whole have become severe, such as the rotational speed of the planetary gear being increased. Along with this, there is a further demand for improved lubrication, and in order to improve the lubrication, the amount of oil supplied is increased, the number of oil holes in the pinion shaft is increased, or the oil of the pinion shaft is increased. The first possibility is to increase the hole diameter. However, even if the supply amount of the lubricating oil is simply increased in this way, it is difficult to increase the amount of oil that actually reaches the needle roller bearing in proportion thereto.

  In addition, the rolling fatigue life of needle roller bearings (the total number of revolutions until the rolling parts become fatigued due to repeated shear stress applied to the rolling surface as the bearing rotates and the surface partly peels) In order to increase the length, it is required to sufficiently supply lubricating oil to the rolling surface to hold the oil film.

  As a countermeasure, as shown in FIG. 4, a needle roller bearing 70 is known in which a corner portion 73 of a pocket 72 of a cage 71 is provided with a relief portion 74 (see, for example, Patent Document 1).

  The needle roller bearing 70 disclosed in this patent document 1 holds the thin portion 74 as a lubricating oil flow passage by setting the depth of the thin portion 74 to a predetermined value with respect to the diameter of the needle roller 75. The lubricating oil is to be spread smoothly between the inner diameter side and the outer diameter side of the vessel 71.

  Further, as shown in FIG. 5, a needle roller bearing 80 is proposed in which the thickness of the central portion of the column portion 83 of the retainer 82 that holds the needle rollers 81 is thinner than other portions (for example, , See Patent Document 2).

  In the needle roller bearing 80 disclosed in Patent Document 2, the thickness t1 of the reduced diameter portion 84, which is the center portion of the column portion 83, is changed from the thickness t2 of the guide surface 85, which is the other portion, and the annular portion. By reducing the thickness of the flange portion 86 to less than or less than 86, the weight is reduced.

Japanese Patent Laid-Open No. 11-108065 JP 2004-353809 A

  However, in the conventional needle roller bearing 70 disclosed in Patent Document 1, the width of the column portion of the retainer 71 is narrowed at the corner portion 73 of the pocket 72 where stress tends to concentrate. There is a risk that the retainer 71 may be damaged, causing problems such as dropping of the needle rollers.

  Further, in the conventional needle roller bearing 80 disclosed in Patent Document 2, the retainability of the needle roller 81 is not reliable in the contact between the corner portion of the column portion 83 of the cage 82 and the needle roller 81. There is a concern and there is room for improving the flowability of the lubricating oil.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to efficiently remove lubricating oil on the rolling surface with a limited amount of lubricating oil without impairing the retainability to the needle rollers. It is providing the needle roller bearing which can be hold | maintained.

  The object of the present invention described above is achieved by the following configuration.

(1) It has a pair of annular parts arranged at intervals in the axial direction, and a plurality of column parts intermittently arranged in the circumferential direction to connect the pair of annular parts. A needle roller bearing comprising: a cage in which a plurality of pockets are formed between the annular portion and the column portion; and a plurality of needle rollers that are rotatably held in the pockets. The column portions extend inward in the axial direction from the peripheral edges of the pair of annular portions, respectively, and a pair of end plate portions positioned at both axial end portions, respectively, and are positioned in the axial direction and radially contracted inward. A central plate portion that is radially arranged and arranged radially inward of the pair of end plate portions, an axially inner end portion of the pair of end plate portions, and both axial end portions of the central plate portion the has a pair of swash plate portion connecting in a state tilted with respect to the axial direction, and in the middle of the central plate portion, the narrower toward the circumferential direction Narrow portion is provided, the axial length of the pocket L1, the axial length of the central plate portion L2, the axial length of the narrow section L3, the circumferential width dimension of the central plate portion Is L4, and when the circumferential width dimension of the narrow portion is L5, L1>L2> L3 and L4> L5 are provided. And a rolling surface of the needle roller, a gap serving as a flow path for the lubricating oil is formed .
(2) The needle roller bearing according to (1), wherein a circumferential edge of the narrow portion is chamfered.
( 3 ) The needle roller bearing according to (1) or (2) , which is used for supporting a planetary gear in a planetary gear mechanism in which both ends of a pinion shaft are supported by a carrier.

According to the configuration described in the above (1), the flow path of the lubricating oil from the outer diameter side and the inner diameter side of the cage is formed through the narrow portion narrow in the circumferential direction at the intermediate position of the column portion. Thereby, the lubricating oil on the rolling surface can be efficiently held with a limited amount of lubricating oil. In addition, since the capacity is reduced in the middle of the column part, even if a centrifugal force is applied during rotation, the column part is prevented from being deformed due to its own weight and does not impair the retainability to the needle rollers. .
Further, according to the configuration described in (2) above, the circumferential edge of the narrow portion is chamfered so that contact with the needle rollers and fluidity of the lubricating oil are taken into consideration. Can do.
And according to the structure as described in said ( 3 ), the lubricating oil which flowed out from the oil hole through the shaft center of a pinion shaft passes the rolling surface of a needle roller and a pinion shaft, and it is a planetary gear. It is pushed out to the outer diameter side of the cage by the centrifugal force due to the rotation of. At that time, since the pinion shaft and the column part have a narrow part that is narrow in the middle of the column part that is closest, a gap is secured between the column part and the needle roller, Lubricating oil efficiently flows to the outer diameter side of the cage through the gap. For this reason, even in the planetary gear mechanism in which the lubricating oil is not sufficiently distributed by a complicated mechanism, the lubricating oil on the rolling surface can be efficiently held with a limited amount of lubricating oil. Furthermore, in order to reduce the capacity of the intermediate portion of the column portion where the amount of bending is maximum, the narrow portion is deformed due to its own weight even if the centrifugal force due to the revolution and rotation of the planetary gear is applied. By being suppressed, the stress concentration on the corner portion is reduced, and the retainability with respect to the needle rollers is not impaired.

  ADVANTAGE OF THE INVENTION According to this invention, the needle roller bearing which can hold | maintain the lubricating oil on a rolling surface efficiently with the limited amount of lubricating oil can be provided, without impairing the retainability with respect to a needle roller. .

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of a needle roller bearing according to the present invention, FIG. 1 is an external perspective view of the needle roller bearing according to an embodiment of the present invention, and FIG. 1 is a partially broken side view of the needle roller bearing 1 and FIG. 3 is an exploded perspective view of a planetary gear mechanism to which the needle roller bearing of FIG. 1 is applied.

As shown in FIG. 1, a needle roller bearing 10 according to an embodiment of the present invention includes a cage 11 and a plurality of needle rollers 12.
In this embodiment, since it is used for a planetary gear mechanism described later, it does not have a structure directly provided with an inner ring equivalent member and an outer ring equivalent member, but a needle provided with at least one of various outer ring equivalent members or inner ring equivalent members. The present invention can be appropriately applied to a tapered roller bearing.

  The cage 11 is formed by punching and bending a metal plate member such as a steel material for machine structure, for example, and a pair of annular portions 13 that are spaced apart from each other in the axial direction, and a circumferential direction. And a plurality of column portions 14 that are intermittently arranged to connect the pair of annular portions 13, and are formed with a pocket 15 between the pair of annular portions 13 and the column portions 14. Each is formed at equal intervals in the circumferential direction.

The column portion 14 functions as a stopper for the needle rollers 12 by the central plate portion 16 disposed in the middle in the axial direction being reduced in diameter toward the inner peripheral portion in a stepped shape, and this center A narrow portion 17 described later is formed at an intermediate position of the plate portion 16.

  Since the needle roller 12 is formed in a round bar shape, and after quenching, an appropriate crowning process is performed after the grinding finish, so that stress concentration at both ends can be reduced.

  As shown in FIG. 2, in the retainer 11, the pocket 15 has an axial length of the length dimension L1, and the central plate portion 16 has an axial length of the length dimension L2 and the narrow portion 17. Has a length in the axial direction of the length dimension L3, and the relationship between these lengths is L1> L2> L3.

Here, concave portions are formed at both ends in the circumferential direction of the central plate portion 16, and therefore when the central plate portion 16 has a width dimension L4 in the circumferential direction, the narrow portion 17 has this width dimension in the circumferential direction. The width L5 is narrower than L4 (ie, L4> L5).
Therefore, the narrow portion 17 forms a gap between the retainer 11 and the rolling surface of the needle roller 12 at the intermediate portion of the central plate portion 16, thereby forming a lubricating oil flow path. Become.
In consideration of the contact with the needle roller 12 and the fluidity of the lubricating oil, the circumferential edge of the narrow portion 17 is chamfered, and the periphery of the axial end portion of the narrow portion 17 is also provided. The surface is preferably a continuous surface having a relatively smooth curve.

As shown in FIG. 3, the needle roller bearing 10 configured in this way is assembled to each of the three planetary gears 31 in the planetary gear mechanism 30.
The planetary gear mechanism 30 includes a ring gear 32 having inner teeth 33, a sun gear 34 having outer teeth 35, a planetary gear 31 meshing with the inner teeth 33 of the ring gear 32 and the outer teeth 35 of the sun gear 34, and a non-rotating gear. Three pinion shafts 36 each having the illustrated oil hole and supporting the planetary gear 31, and a carrier 37 that supports both ends of the pinion shaft 36 to rotatably support the planetary gear 31 and can also rotate itself. And comprising. The needle roller bearing 10 is fitted on the pinion shaft 36, the cage 11 is attached to the planetary gear 31 with an outer diameter support, and the bearing space is filled with a predetermined lubricating oil.

  For example, in the case of the first speed, the planetary gear mechanism 30 can obtain a large reduction ratio by fixing the ring gear 32 with the sun gear 34 as the drive side and the planetary gear 31 and the carrier 37 as the driven side. For example, in the case of the second speed, a moderate reduction ratio can be obtained by fixing the sun gear 34, the planetary gear 31 and the carrier 37 on the driven side, and the ring gear 32 on the drive side. Further, for example, in the case of the third speed, a small reduction ratio can be obtained by fixing the sun gear 34, the planetary gear 31 and the carrier 37 on the drive side, and the ring gear 32 on the driven side.

  Unlike these, for example, in the case of reverse, the sun gear 34 is driven, the planetary gear 31 and the carrier 37 are fixed, and the ring gear 32 is driven, so that the output is reversed with respect to the input. be able to. As described above, the planetary gear mechanism 30 can perform the speed change of the third speed and the reduction of the reverse speed, but these rotational operations are merely examples, and are not necessarily limited to these operations.

  In such a rotation operation, the lubricating oil flowing out from the oil hole of the pinion shaft 36 passes through the rolling surfaces of the pinion shaft 36 and the needle rollers 12 and is held by the centrifugal force due to the rotation of the planetary gear 31. It is pushed out to the outer diameter side of the vessel 11. At that time, the lubricating oil is efficiently transferred to the outer diameter side of the cage 11 through a gap (flow path) formed by the narrow portion 17 at the intermediate portion of the column portion 14 where the pinion shaft 36 and the column portion 14 are closest to each other. Well fluidized.

  As described above, according to the needle roller bearing 10 of the present embodiment, the lubricating oil from the outer diameter side and the inner diameter side of the cage 11 through the narrow portion 17 that is narrow in the circumferential direction in the middle of the column portion 14. The flow path is formed. Thereby, the lubricating oil on the rolling surface can be efficiently held with a limited amount of lubricating oil. Moreover, even if the centrifugal force at the time of rotation is loaded by the capacity | capacitance reducing in the middle of the pillar part 14 by the narrow part 17, the deformation | transformation accompanying the dead weight is suppressed and the needle part 14 is suppressed. The retainability with respect to 12 is not impaired.

Further, according to the needle roller bearing 10 of the present embodiment, when assembled in the planetary gear mechanism 30, the lubricating oil flowing out from the oil hole of the pinion shaft 36 is transferred to the pinion shaft 36, the needle roller 12, and the like. And is pushed to the outer diameter side of the cage 11 by the centrifugal force due to the rotation of the planetary gear 31. At that time, since the width of the narrow portion 17 is narrow at the intermediate portion of the column portion 14 where the pinion shaft 36 and the column portion 14 are closest to each other, there is a gap between the column portion 14 and the needle roller 12. As a result, the lubricating oil efficiently flows to the outer diameter side of the cage 11 through the gap. For this reason, even in the planetary gear mechanism 30 in which the lubricating oil is not sufficiently distributed by a complicated mechanism, the lubricating oil on the rolling surface can be efficiently held with a limited amount of lubricating oil.
Further, the narrow portion 17 reduces the capacity at the intermediate portion of the column portion 14 where the amount of deflection is maximized, so that the column portion 14 has its own weight even if the centrifugal force due to the revolution and rotation of the planetary gear 31 is applied. Suppressing the deformation associated with, the stress concentration on the corner portion is reduced, and the retainability to the needle rollers is not impaired.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimension, numerical value, form, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, the number of needle rollers, the outer diameter, the length, and the like are not limited at all because they are appropriately set in consideration of the torque capacity and the like of the applied planetary gear. Of course, the outer diameter of the cage, the number of pillars, the number of pockets, and the like are appropriately set based on required specifications in accordance with the total number, outer diameter, and length of the needle rollers.

1 is an external perspective view of a needle roller bearing according to an embodiment of the present invention. It is a partially broken side view of the needle roller bearing of FIG. It is a disassembled perspective view of the planetary gear mechanism to which the needle roller bearing of FIG. 1 is applied. It is a fragmentary sectional view of the conventional needle roller bearing. It is a fragmentary sectional view of the conventional needle roller bearing different from FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Needle roller bearing 11 Cage 12 Needle roller 13 Annular part 14 Column part 15 Pocket 17 Narrow part 30 Planetary gear mechanism 31 Planetary gear 36 Pinion shaft 37 Carrier

Claims (3)

A pair of annular portions arranged at intervals in the axial direction, and a plurality of column portions that are intermittently arranged in the circumferential direction to connect the pair of annular portions, A needle roller bearing comprising: a cage in which a plurality of pockets are formed between an annular portion and the column portion; and a plurality of needle rollers that are rotatably held in the pocket,
The column portions extend inward in the axial direction from the peripheral edges of the pair of annular portions, respectively, and a pair of end plate portions positioned at both axial ends, respectively, and are positioned in the axial direction and radially reduced in diameter. A central plate portion disposed radially inward of the pair of end plate portions, an axially inner end portion of the pair of end plate portions, and both axial end portions of the central plate portion. A pair of swash plate portions that are connected in an inclined state with respect to the axial direction,
In the middle of the central plate portion, a narrow portion that is narrow toward the circumferential direction is provided ,
The axial length of the pocket is L1, the axial length of the central plate is L2, the axial length of the narrow portion is L3, the circumferential width of the central plate is L4, and the width. When the circumferential width dimension of the narrow portion is L5, L1>L2> L3 and L4> L5 are provided.
Thus, a needle roller bearing is characterized in that a gap serving as a flow path for lubricating oil is formed between the cage and the rolling surface of the needle roller at an intermediate portion of the central plate portion . The needle roller bearing according to claim 1, wherein the circumferential edge portion of the narrow portion is chamfered. The needle roller bearing according to claim 1 or 2 , which is used for supporting a planetary gear in a planetary gear mechanism in which both ends of a pinion shaft are supported by a carrier.

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