JP2015045368A - Rolling bearing and power transmission device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing which generates air bubbles in a lubrication oil to reduce viscous resistance of the lubrication oil without disposing a special air bubble generator, and to provide a power transmission device using the rolling bearing.SOLUTION: A rolling bearing includes: an inner race 31; an outer race 40 which is concentrically disposed on an outer peripheral surface of the inner race 31 forming an annular space therebetween; multiple rolling elements 50 which are disposed in the annular space so as to roll; and a holder 60 which holds the multiple rolling elements 50. A liquid lubrication oil flows through the annular space. A holder air bubble generating mechanism 70 which generates air bubbles in the lubrication oil during bearing rotation is provided at the holder 60.

Description

  The present invention relates to a rolling bearing and a power transmission device using the rolling bearing.

Conventionally, in rolling bearings, for example, there is one disclosed in Patent Document 1 in order to reduce torque resistance by reducing the viscous resistance of lubricating oil.
In this, a bubble generating device (micro bubble generating device) is arranged outside the rolling bearing, the bubbles generated by the bubble generating device are mixed into the lubricating oil, and supplied into the rolling bearing, thereby the lubricating oil. Reduces viscous resistance.

JP 2008-82547 A

  By the way, in what was disclosed by patent document 1, the exclusive bubble generator for mixing and supplying a bubble in lubricating oil must be arrange | positioned with respect to the exterior of a rolling bearing, and only a cost increases. In addition, a space for placing the bubble generating device must be secured.

  In view of the above problems, an object of the present invention is to provide a rolling bearing and a rolling bearing capable of reducing the viscous resistance of the lubricating oil by generating bubbles in the lubricating oil without arranging a dedicated bubble generating device. It is to provide a power transmission device used.

  In order to solve the above problems, the invention of claim 1 is provided with an inner ring, an outer ring disposed concentrically on the outer peripheral surface of the inner ring with an annular space therebetween, and a rollable arrangement in the annular space. A rolling bearing of a type comprising a plurality of rolling elements and a cage for holding the plurality of rolling elements, wherein liquid lubricating oil flows through the annular space, wherein the cage includes the lubricating oil when the bearing rotates. A cage bubble generation mechanism for generating bubbles therein is provided.

According to the first aspect of the present invention, when the bearing rotates, the liquid lubricating oil flows through the annular space between the inner ring and the outer ring.
At this time, bubbles are generated in the lubricating oil by the cage bubble generating mechanism provided in the cage, thereby reducing the viscous resistance of the lubricating oil.
In this way, since the viscous resistance of the lubricating oil can be reduced by an extremely simple structure in which a cage bubble generation mechanism is provided in the cage, unlike the conventional case, a space for arranging a dedicated bubble generator is provided. The need to secure and install can be eliminated.

  A second aspect of the present invention is the rolling bearing according to the first aspect, wherein the cage bubble generating mechanism is constituted by a large number of concave portions formed on an axial end surface of the cage.

According to the invention of claim 2, the cage bubble generating mechanism can be easily configured by forming a large number of recesses in the cage.
In this case, bubbles can be generated in the lubricating oil by entraining bubbles such as air taken into a large number of recesses of the cage with the rotation of the cage. This reduces the viscous resistance of the lubricating oil.
Moreover, since the surface area of the rotation-side race is increased by the large number of recesses, the heat dissipation can be improved by this amount.

  Invention of Claim 3 is a rolling bearing of Claim 1 or 2, Comprising: The said rolling element is a tapered roller, The flange part extended in radial direction in the small diameter side annular part of the said holder | retainer The cage bubble generating mechanism is constituted by a large number of recesses formed in the axial end surface of the flange portion.

  According to the invention of claim 3, when the roller is a tapered roller (that is, a tapered roller bearing), a large amount of lubricating oil flows from the small diameter side toward the large diameter side due to the pumping action when the bearing rotates. As a result, the torque due to the stirring resistance of the lubricating oil tends to increase. However, since bubbles such as air taken into a large number of recesses formed on the axial end face of the flange portion of the cage can be generated in the lubricating oil, bubbles can be generated in the lubricating oil. The viscous resistance can be reduced and the torque can be reduced.

  A fourth aspect of the present invention is the rolling bearing according to any one of the second or third aspects, wherein the plurality of concave portions constituting the cage bubble generating mechanism are configured so that the lubricating oil in the concave portions is not rotated when the bearing rotates. The pressure is reduced to below the melting limit pressure.

  According to the invention of claim 4, with the rotation of the cage, when the pressure of the lubricating oil in the many recesses of the cage is reduced to below the solubility limit, a gas such as air dissolved in the lubricating oil, Bubbles can be generated by coming out of the lubricating oil. This can also reduce the viscous resistance of the lubricating oil.

  A fifth aspect of the present invention is the rolling bearing according to any one of the second or third aspects, wherein a large number of concave portions constituting the cage bubble generating mechanism are formed by lubricating oil in the concave portions during rotation of the bearing. The pressure is changed from the liquid phase to the gas phase, and the pressure is reduced so as to be equal to or lower than the saturated vapor pressure.

According to the invention of claim 5, when the pressure of the lubricating oil in the many recesses of the cage is equal to or lower than the saturated vapor pressure at which the liquid phase changes to the gas phase, a part of the lubricating oil changes from the liquid phase to the gas phase. Thus, bubbles can be generated in the lubricating oil. Thereby, the viscous resistance of the lubricating oil can be reduced.
It can also be expected that the lubricating oil is cooled by the heat of vaporization of the lubricating oil that has changed from the liquid phase to the gas phase.

  The power transmission device using the rolling bearing of the invention of claim 6 is a rolling bearing according to any one of claims 1 to 5 as a rolling bearing for rotatably supporting a rotating shaft inside the power transmission device. A bearing is used.

  According to the power transmission device using the rolling bearing of the invention of claim 6, by using the rolling bearing of claim 1 or 2, the viscous resistance of the lubricating oil can be reduced and the torque can be reduced.

  According to the present invention, the viscosity resistance of the lubricating oil can be reduced and the torque can be reduced by the cage bubble generation mechanism provided in the cage.

It is an axial sectional view showing the rolling bearing according to the first embodiment of the present invention. It is an axial direction sectional view which expands and similarly shows the relation of an inner ring, an outer ring, a tapered roller, and a cage. It is a perspective view which similarly shows a holder | retainer. It is explanatory drawing which shows many recessed parts which comprise the cage bubble generation mechanism similarly formed in the small diameter side end surface of the axial direction of a cage. It is explanatory drawing which shows many recessed parts which comprise the cage bubble generation mechanism similarly formed in the large diameter side end surface of the axial direction of a cage. It is explanatory drawing which shows the state which the low voltage | pressure part generate | occur | produced behind the inner wall surface located in the rotation direction front side of many recessed parts which comprises a vaporizer bubble generation mechanism similarly. BRIEF DESCRIPTION OF THE DRAWINGS It is an axial sectional view which shows the differential apparatus as a power transmission device using the rolling bearing which concerns on Example 1 of this invention.

  A mode for carrying out the present invention will be described according to an embodiment.

A first embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the tapered roller bearing 30 as a rolling bearing includes an inner ring 31, an outer ring 40, a plurality of tapered rollers 50, and a cage 60.
The inner ring 31 has a central hole and is formed in a cylindrical shape. A tapered shaft-shaped inner ring raceway surface 32 that is gradually enlarged in diameter from one end to the other end is formed on the outer peripheral surface.
A small brim 33 having a guide surface 34 for guiding the small end surface 51 of the tapered roller 50 is formed on the outer peripheral surface of one end of the inner ring 31 (the smaller diameter side of the inner ring raceway surface 32). A large collar portion 35 having a guide surface 36 for guiding the large end surface 52 of the tapered roller 50 is formed on the surface (large diameter side of the inner ring raceway surface 32).

The outer ring 40 is disposed concentrically on the outer peripheral surface of the inner ring 31 with an annular space therebetween, forming a cylindrical shape, and the inner peripheral surface has a tapered hole that gradually increases in diameter from one end to the other end. An outer ring raceway surface 41 is formed.
In an annular space between the inner ring raceway surface 32 of the inner ring 31 and the outer ring raceway surface 41, a plurality of tapered rollers 50 are disposed so as to be able to roll while being held by a cage 60.

The cage 60 is formed of a metal material or a resin material, and as shown in FIGS. 2 and 3, a small-diameter-side annular portion 61, a large-diameter-side annular portion 62, and both of these annular portions that are spaced apart from each other in the axial direction. A pocket 64 for holding the tapered roller 50 is formed in a portion surrounded by the annular portions 61 and 62 and the pillar portion 63.
Further, in the first embodiment, a flange portion bent radially inward to a position approaching the outer peripheral surface of the small collar portion 33 of the inner ring 31 at the axial end edge of the small diameter side annular portion 61 of the cage 60. 61a is formed.
The tapered roller bearing 30 is configured in such a manner that liquid lubricating oil flows through an annular space between the inner ring 31 and the outer ring 40.

The cage 60 is provided with a cage bubble generation mechanism 70 that generates bubbles in the lubricating oil when the bearing rotates. The cage bubble generation mechanism 70 is configured by a large number of recesses 72 formed on the axial end surface of the cage 60.
In the first embodiment, as shown in FIGS. 3 to 5, both axial end surfaces of the retainer 60, that is, the axial end surface including the flange portion 61 a of the small-diameter-side annular portion 61 of the retainer 60, and the large-diameter side A large number of recesses 72 constituting the cage bubble generating mechanism 70 are formed on the end surface in the axial direction of the annular portion 62.
Further, the size of the recess 72 is, for example, formed such that the diameter dimension is around 10 μm and the depth dimension is around 5 μm.

When the cage 60 is made of metal, the numerous recesses 72 are formed by etching or shot blasting.
When the cage 60 is made of resin, convex portions for forming a large number of concave portions 72 are formed on the mold surface of the molding die that forms the cage 60, and the resin material is injected into the molding die. At the same time as the cage 60 is formed, a large number of recesses 72 can be formed on both end surfaces of the cage 60 in the axial direction.

In addition, it is desirable to set the numerous recesses 72 constituting the cage bubble generating mechanism 70 so that the pressure of the lubricating oil in the recesses 72 is reduced to a melting limit pressure or less when the bearing rotates. The solubility limit pressure refers to a pressure at which a gas such as air dissolved in the lubricating oil under normal pressure cannot be maintained in the state of being dissolved in the lubricating oil due to the pressure of the lubricating oil and is bubbled.
In addition, the large number of recesses 72 constituting the cage bubble generation mechanism 70 are changed so that the pressure of the lubricating oil in the recesses 72 is changed from the liquid phase to the gas phase when the bearing rotates, and the pressure is reduced to be equal to or lower than the saturated vapor pressure. It is desirable to set.

The tapered roller bearing as the rolling bearing according to the first embodiment is configured as described above.
Accordingly, during the rotation of the bearing, liquid lubricating oil flows through the annular space between the inner ring 31 and the outer ring 40.
At this time, bubbles are generated in the lubricating oil by the cage bubble generating mechanism 70 provided in the cage 60, thereby reducing the viscous resistance of the lubricating oil.
In this manner, since the viscous resistance of the lubricating oil can be reduced by a very simple structure in which the cage 60 is provided with the cage bubble generation mechanism 70, a dedicated bubble generator is arranged unlike the conventional case. The need to secure and install space can be eliminated.

In the first embodiment, a large number of concave portions 72 are formed on both end surfaces of the cage 60 in the axial direction.
Then, as the cage 60 rotates, bubbles such as air taken into a large number of recesses 72 formed on both axial end surfaces of the cage 60 are entrained in the lubricant so that the bubbles are introduced into the lubricant. Can be generated. This reduces the viscous resistance of the lubricating oil.
In addition, since the surface area of the cage 60 is increased by the large number of recesses 72 formed on both end surfaces in the axial direction of the cage 60, the heat dissipation can be improved by this amount.

Further, during the rotation of the bearing, as shown in FIG. 6, among the inner wall surfaces of the numerous recesses 72 constituting the cage bubble generation mechanism 70, the inner wall surface located on the front side in the rotation direction (the arrow P direction in FIG. 6). A low pressure part 90 is generated in the rear.
In the first embodiment, the pressure of the lubricating oil in the large number of recesses 72 is set so as to reduce the pressure in the low pressure portion 90 to below the dissolution limit.
When the pressure of the lubricating oil in the numerous recesses 72 is reduced to below the dissolution limit as the inner ring 31 rotates, a gas such as air dissolved in the lubricating oil comes out of the lubricating oil and bubbles. Can be generated. This can also reduce the viscous resistance of the lubricating oil.

Further, in the first embodiment, the pressure of the lubricating oil is set to be equal to or lower than the saturated vapor pressure at which the pressure of the lubricating oil changes from the liquid phase to the gas phase in the low pressure portions 90 in the numerous recesses 72 when the bearing rotates.
As a result, the pressure of the lubricating oil becomes lower than the saturated vapor pressure at which the pressure of the lubricating oil changes from the liquid phase to the gas phase at the low pressure portions 90 in the numerous recesses 72. And a part of lubricating oil can change from a liquid phase to a gaseous phase, and a bubble can be generated in lubricating oil. Thereby, the viscous resistance of the lubricating oil can be reduced.
It can also be expected that the lubricating oil is cooled by the heat of vaporization of the lubricating oil that has changed from the liquid phase to the gas phase.
As a result, it is possible to provide a tapered roller bearing 30 suitable as a high-speed rotation rolling bearing.

Next, a power transmission device using the tapered roller bearing 30 as the rolling bearing described in the first embodiment, for example, the differential device 10 will be described with reference to FIG.
As shown in FIG. 7, bearing housings 12 and 13 are formed in the differential carrier 11 of the differential device 10 so as to be spaced apart from each other in the axial direction.
Front and rear tapered roller bearings 30 and 80 for rotatably supporting front and rear portions of the pinion shaft 21 (corresponding to the rotating shaft of the present invention) are assembled to the bearing housings 12 and 13, respectively.
The tapered roller bearing described in the first embodiment is used for at least one of the tapered roller bearings 30 and 80.

Further, one end portion of both end portions of the pinion shaft 21 protrudes from the differential carrier 11, and a companion flange 23 connected to a propeller shaft (not shown) is assembled to the one end portion. A pinion 22 that meshes with a ring gear 20 assembled in a differential case (not shown) in the differential carrier 11 is provided at the other end of the pinion shaft 21 so as to transmit torque. The ring gear 20 and the pinion 22 constitute a final reduction mechanism.
A spacer member 26 is interposed between the inner rings 31 and 81 of the tapered roller bearings 30 and 80.
Further, the lower portion in the differential carrier 11 is filled with lubricating oil up to a predetermined oil level and sealed.
As is well known, a differential gear mechanism is built in a differential case (not shown).

  As shown in FIG. 7, a lubrication flow path 14 into which the lubricating oil pumped up by the rotation of the ring gear 20 flows is formed at the upper part of the bearing housing 12 in the differential carrier 11. In the upper part, a supply port 15 for supplying the lubricating oil flowing through the lubricating flow path to the tapered roller bearings 30 and 80 is formed.

The differential device 10 using the tapered roller bearing 30 described in the first embodiment is configured as described above.
Accordingly, the lubricating oil accumulated in the lower portion of the differential carrier 11 is agitated as the ring gear 20 rotates during traveling of the vehicle, and a portion of the lubricating oil flows into the lubricating flow path 14 toward the supply port 15. Flowing. The lubricating oil is supplied from the supply port 15 to the small-diameter side of the annular space of the front and rear tapered roller bearings 30 and 80.
The inner rings 31 and 81 of the both tapered roller bearings 30 and 80 rotate integrally with the pinion shaft 21 that rotates by receiving torque transmission from the ring gear 20. As a result, the tapered roller 50 rolls and the cage 60 rotates.
Further, the lubricating oil supplied to the small diameter side of the annular space of the front and rear tapered roller bearings 30, 80 flows and is discharged toward the large diameter side of the annular space by the pump action based on the rolling of the tapered roller 50. The

  Of the front and rear tapered roller bearings 30 and 80, at least one of the tapered roller bearings 30 is the tapered roller bearing described in the first embodiment. For this reason, bubbles taken in a large number of recesses 72 formed on both end surfaces in the axial direction of the cage 60 of the tapered roller bearing 30 are mixed in the lubricating oil. As a result, the viscous resistance of the lubricating oil is reduced, so that the torque can be reduced well.

In addition, this invention is not limited to the said Example 1, In the range which does not deviate from the summary of this invention, it can implement with a various form.
For example, in the first embodiment, the cage bubble generation mechanism 70 is provided on each of the axial end surface including the flange portion 61 a of the small-diameter side annular portion 61 of the cage 60 and the axial end surface of the large-diameter side annular portion 62. Is formed, but one of the axial end surface including the flange portion 61a of the small-diameter side annular portion 61 of the retainer 60 and the axial end surface of the large-diameter side annular portion 62 is illustrated. In addition, the present invention can be implemented even when a large number of recesses 72 constituting the cage bubble generating mechanism 70 are formed.
Further, at least one of the cage components of the cage 60 other than the axial end faces, for example, the small-diameter-side annular portion 61, the large-diameter-side annular portion 62, and the column portion 63. The present invention can also be implemented by forming a large number of recesses constituting the cage bubble generating mechanism on the outer diameter side surface and / or the inner diameter side surface of the component.
Moreover, in the said Example 1, although the case where the rolling bearing was the tapered roller bearing 30 was illustrated, a cylindrical roller bearing may be sufficient and a ball bearing may be sufficient.
Further, the power transmission device may be other than the differential device, for example, a transaxle device or the like.

10 Differential device (power transmission device)
11 Differential carrier 12, 13 Bearing housing 21 Pinion shaft (rotating shaft)
30 Rolling bearing 31 Inner ring 33 Small collar part 35 Large collar part 40 Outer ring 50 Tapered roller 60 Cage 70 Cage bubble generating mechanism 72 Numerous recesses

Claims (6)

An inner ring, an outer ring disposed concentrically on the outer peripheral surface of the inner ring with an annular space therebetween, a plurality of rolling elements arranged to roll in the annular space, and a holding for holding the plurality of rolling elements A rolling bearing of a type in which liquid lubricating oil flows through the annular space,
A rolling bearing according to claim 1, wherein the cage is provided with a cage bubble generating mechanism for generating bubbles in the lubricating oil when the bearing rotates. The rolling bearing according to claim 1,
A rolling bearing according to claim 1, wherein the cage bubble generating mechanism is constituted by a large number of concave portions formed on an axial end surface of the cage. A rolling bearing according to claim 1 or 2,
The rolling element is a tapered roller,
A flange portion extending radially inward is formed on the small-diameter side annular portion of the cage,
The rolling element bearing is characterized in that the cage bubble generating mechanism is constituted by a large number of recesses formed on an end surface in the axial direction of the flange portion. A rolling bearing according to any one of claims 2 or 3,
A rolling bearing characterized in that a large number of recesses constituting the cage bubble generating mechanism reduce the pressure of the lubricating oil in the recesses to a melting limit pressure or less when the bearing rotates. A rolling bearing according to any one of claims 2 or 3,
A number of recesses constituting the cage bubble generating mechanism are characterized in that the pressure of the lubricating oil in the recesses is changed from a liquid phase to a gas phase when the bearing rotates, and the pressure is reduced to be equal to or lower than a saturated vapor pressure. Rolling bearing.   A rolling bearing characterized in that the rolling bearing according to any one of claims 1 to 5 is used as a rolling bearing for rotatably supporting a rotating shaft inside a power transmission device. Power transmission device.

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