JP2005180531A - Air oil lubricating structure of rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air oil lubricating structure of a rolling bearing, stably performs low-noise air oil lubrication without addition of separate parts or without parts of special width and shapes even in the case of a small-diameter bearing or a bearing having small size from the raceway surface to the width surface. <P>SOLUTION: An outside diameter surface of an inner ring 2 of the rolling bearing 1 is provided with a slant part 2b connected to the raceway surface 2a of the inner ring 2, and with a nozzle member 6 laid along the slant part 2b with a clearance gap δ. A circumferential groove side wall surface 2c formed by a slant more steep than the slant part 2b is provided on the inner ring width surface side from the slant part 2b of the inner ring 2. The circumferential groove 7 is formed of a chamfered part 11a on the outside diameter side of an inner ring spacer 11 adjacent to the inner ring 2 and the circumferential groove side wall surface 2c. The nozzle member 6 is provided with an air oil delivery hole 8 opened opposite to the circumferential groove 7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an air-oil lubrication structure for a rolling bearing used to support high-speed rotation of a main shaft or the like of a machine tool.

  The main spindle of machine tools tends to increase in speed in order to increase machining efficiency. For this reason, the lubrication of the bearing is also increasing in the amount of air oil lubrication in which lubricating oil is mixed with the carrier air and sprayed directly onto the inner ring rolling surface. However, in order to spray air oil directly onto the inner ring rolling surface, it is necessary to overcome the wind pressure generated by the revolution of the rolling element and allow the lubricating oil to reach the raceway surface. Need to increase speed. For this reason, energy consumption increases due to an increase in the amount of air, and noise due to repeated interruption and penetration of the air flow caused by the revolution of the rolling element, that is, wind noise, is generated.

  An air-oil lubrication structure having a configuration shown in FIG. 4 has been proposed as a solution to the above-described energy consumption and noise in the direct-jet air-oil lubrication (for example, Patent Document 1). In the air-oil lubrication structure of the same figure, an inclined surface portion 62b following the raceway surface 62a of the inner ring 62 is provided on the outer diameter surface of the inner ring 62 of the rolling bearing 61, and a nozzle member 66 extending along the inclined surface portion 62b with a gap δ is provided. And a circumferential groove 67 is provided on the slope portion 62b. The nozzle member 66 is provided with an air oil discharge hole 68 that opens to face the slope portion 62b.

  In the case of the air-oil lubrication structure shown in FIG. 2, air oil, which is lubricating oil mixed with the carrier air, is discharged from the discharge hole 68 of the nozzle member 66 to the circumferential groove 67 of the inner ring 62, and the inclined surface 62b of the inner ring 62 and the nozzle member From the gap δ between 66, it is guided to the inside of the bearing by the negative pressure suction action generated during the bearing operation. Further, it is guided to the raceway surface 62a inside the bearing or the inner diameter surface of the cage 65 by the surface tension of the lubricating oil adhering to the inclined surface portion 62b and the component force of the centrifugal force toward the larger diameter side of the inclined surface portion 62b. In this case, because of the circumferential groove 67 provided in the inner ring 62, an effect of spreading the air oil discharged from the discharge hole 68 over the entire circumference is obtained. For this reason, even if the amount of air oil discharged is small and the air is unevenly distributed on the circumference, there is no oil stagnation due to the centrifugal force acting on the inner ring slope portion 62b. Lubricating oil can be supplied into the bearing.

Thus, by providing the inclined surface portion 62b and the circumferential groove 67, it is possible to stably supply lubricating oil to the raceway surface 62a without blowing air oil directly to the raceway surface 62a, and to reduce noise caused by wind noise. It becomes possible to reduce and to reduce the amount of conveyance air. Further, it is possible to prevent the bearing temperature from fluctuating due to oil retention in a small amount of air.
JP 2002-54643 A Japanese Patent Laid-Open No. 2001-208085

The conventional air-oil lubrication structure shown in FIG. 4 provides various excellent effects in terms of performance. However, when the bearing size is small, the following manufacturing problems arise. That is, when the bearing size is small and the bearing cross-sectional area is narrowed, the tip of the nozzle member 66 needs to be small in order to avoid interference with the cage 65 and the inner ring 62. However, this requires high-precision processing for processing the nozzle member 66, which increases processing costs. Further, since care is required in handling and assembling work so as not to cause scratches or the like, there is a limit in reducing the size of the tip portion of the nozzle member 66.
The diameter of the discharge hole 68 in the nozzle member 66 should not be further reduced to a limit of about φ0.8 mm from the viewpoints of avoiding clogging, ensuring the air flow rate, and processing even when the bearing size is reduced. It has been. From this point also, it is difficult to reduce the size of the tip of the nozzle member 66.
Further, when the bearing size is reduced, the inner ring inclined surface portion 62b is also reduced, so that the dimension of the circumferential groove 67 cannot be sufficiently ensured.

  As another air-oil lubrication structure, a structure in which a slope portion that receives air oil ejected from the nozzle member is formed on the outer diameter surface of the spacer adjacent to the inner ring of the bearing has been proposed (Patent Document 2). In such a structure, the number of parts increases, and the assembling work to the spindle or the like becomes complicated.

  The object of the present invention is to reduce noise without adding separate parts or special width dimensions and shapes, even for small-diameter bearings and bearings with small dimensions from the raceway surface to the width surface. It is an object of the present invention to provide an air-oil lubrication structure for a rolling bearing capable of stably performing air-oil lubrication.

  In the air-oil lubrication structure for a rolling bearing according to the present invention, an inclined surface portion that follows the raceway surface of the inner ring is provided on the outer diameter surface of the inner ring of the rolling bearing, and a nozzle member is provided along the inclined surface with a gap. Provided on the inner ring width surface side of the slope portion is a circumferential groove side wall surface comprising a slope that is steeper than the slope portion, and the chamfered portion on the outer diameter side of the inner ring spacer adjacent to the inner ring and the circumferential groove A circumferential groove is formed on the side wall surface, and an air oil discharge hole is provided in the nozzle member so as to open facing the circumferential groove. The slope which becomes the circumferential groove side wall surface of the inner ring may be a surface whose cross-sectional shape is a straight line or a curved surface.

According to this configuration, the air oil, which is the lubricating oil mixed with the carrier air, is discharged from the discharge hole of the nozzle member to the circumferential groove extending from the inner ring to the inner ring spacer, and from the gap between the inclined surface of the inner ring and the nozzle member, the bearing It is guided into the bearing by the negative pressure suction action that occurs during operation. Moreover, it is guided to the raceway surface inside the bearing by the surface tension of the lubricating oil adhering to the slope portion and the component force of the centrifugal force toward the large diameter side of the slope portion. In this case, because of the circumferential groove, an effect of spreading the air oil discharged from the discharge hole over the entire circumference can be obtained. For this reason, even if the amount of air oil discharged is small and the air is not evenly distributed on the circumference, there is no stagnation of oil due to the centrifugal force acting on the inclined surface of the inner ring, and the inside of the bearing is stable. Lubricating oil can be supplied.
Thus, since air oil is supplied into the bearing without directly injecting air oil onto the raceway surface of the inner ring, noise due to wind noise can be reduced. In particular, the circumferential groove that receives the air oil injected from the nozzle member is formed by the circumferential groove side wall surface provided in the inner ring and the chamfered portion of the inner ring spacer, so the bearing size is small and the inner ring slope Even when the size of the portion is small, the size of the circumferential groove can be sufficiently secured. As a result, the shape and dimensions of the tip of the nozzle member and the hole diameter of the discharge hole can be taken into consideration in terms of workability and handleability, without adding separate parts or making the nozzle member a special shape or size. In addition, stable lubrication with low noise becomes possible.

In the present invention, the rolling bearing may be a cylindrical roller bearing. In this case, the inner ring of the cylindrical roller bearing may be provided with a flange, and the slope portion of the inner ring may extend from the cylindrical surface portion adjacent to the raceway surface on the outer diameter surface of the inner ring flange to the width surface side. .
In the case of a cylindrical roller bearing, not only when the bearing size is small, but also for the purpose of increasing the load capacity, the dimension from the raceway surface to the width surface is reduced by increasing the roller diameter length. Therefore, the dimension of the part which provides the slope part of an inner ring becomes small. Even in such a case, since the circumferential groove is formed across the inner ring and the inner ring spacer, the groove width dimension of the circumferential groove can be easily secured.

In the present invention, the rolling bearing may be an angular ball bearing, and the slope of the inner ring may be provided on the bearing back side.
Angular contact ball bearings generally have an outer diameter surface on the bearing back side of the inner ring, that is, an outer diameter surface on the front side of the inner ring, as the step surface. Therefore, the step surface can be used as a slope for supplying air oil. Therefore, it is not necessary to form a slope part in particular.

  In the air-oil lubrication structure for a rolling bearing according to the present invention, an inclined surface portion that follows the raceway surface of the inner ring is provided on the outer diameter surface of the inner ring of the rolling bearing, and a nozzle member is provided along the inclined surface with a gap. Provided on the inner ring width surface side of the slope portion is a circumferential groove side wall surface comprising a slope that is steeper than the slope portion, and the chamfered portion on the outer diameter side of the inner ring spacer adjacent to the inner ring and the circumferential groove A circumferential groove is formed on the side wall surface, and an air oil discharge hole that opens to face the circumferential groove is provided in the nozzle member, so that the size from the small diameter bearing and the rolling surface to the width surface is small. Even with a bearing, low-noise air-oil lubrication can be performed stably without adding separate parts or the like, or making the width dimension / shape special.

A first embodiment of the present invention will be described with reference to FIGS. The rolling bearing 1 is a cylindrical roller bearing in which a plurality of rolling elements 4 made of cylindrical rollers are interposed between raceway surfaces 2 a and 3 a of an inner ring 2 and an outer ring 3. Each rolling element 4 is held in each pocket 5 a provided at a plurality of locations in the circumferential direction of the ring-shaped cage 5. The inner ring 2 has flanges on both sides, and the outer ring 3 has no wrinkles.
A slope portion 2b following the raceway surface 2a is provided on the outer diameter surface of the inner ring 2, and a nozzle member 6 is provided along the slope portion 2b with a gap δ. The inclined surface portion 2b extends from the cylindrical surface portion adjacent to the raceway surface 2a on the outer diameter surface of the flange portion of the inner ring 2 to the width surface side. A circumferential groove side wall surface 2c formed of a slope that is steeper than the slope portion 2b is provided on the outer race surface of the inner ring 2 on the inner race width side of the slope portion 2b. A circumferential groove 7 having a V-shaped cross section is formed by the circumferential groove side wall surface 2 c and the chamfered portion 11 a on the outer diameter side of the inner ring spacer 11 adjacent to the inner ring 2. The circumferential groove 7 extends in the circumferential direction and is formed in an annular shape. The inner ring 2 may be one without wrinkles.

  The nozzle member 6 has its tip 6 aa positioned in the vicinity of the rolling element 4 between the inner diameter surface of the cage 5 and the outer diameter surface of the inner ring 2. The nozzle member 6 is a ring-shaped member, and is provided adjacent to the bearing 1 in the axial direction, and has an annular flange-shaped portion 6a extending in the axial direction from the inner diameter portion of the side surface. The flange-shaped portion 6 a has an inner diameter surface formed on an inclined surface having the same angle as that of the inclined surface portion 2 b of the inner ring 2, extends directly below the cage 5, and the tip thereof becomes the tip portion 6 aa of the nozzle member 6. The clearance δ between the flange portion 6a of the nozzle member 6 and the inclined surface portion 2b of the inner ring 2 is in consideration of the fitting between the inner ring 2 and the shaft, the temperature rise of the inner ring 2 and the expansion due to centrifugal force. It is set to a dimension as small as possible (for example, a range of 0.15 to 0.65 mm) as long as it does not touch the surface.

  The nozzle member 6 is provided with a discharge hole 8 facing the circumferential groove 7 and having a discharge port 8a opened. The discharge holes 8 are provided at one place or a plurality of places in the circumferential direction of the nozzle member 6. The discharge hole 8 directs the discharge direction of the discharge port 8a toward the circumferential groove 7 so that the discharged air oil can be directly blown onto the circumferential groove 7, and the discharge direction is a predetermined inclination angle with respect to the bearing axis. Is provided to have.

  The nozzle member 6 is attached to a housing 9 to which the outer ring 3 of the bearing 1 is attached. The nozzle member 6 may be attached to the housing 9 through the outer ring spacer 10 or directly. The example of FIG. 1 is an example attached through an outer ring spacer 10, and a nozzle member 6 is provided in a fitted state in an annular notch recess 10 a formed in the inner diameter part of one side surface of the outer ring spacer 10. . The inner diameter surface outside the bearing of the nozzle member 6 is close enough not to contact the inner ring spacer 11.

  In the discharge hole 8 of the nozzle member 6, the vicinity 8b of the discharge port 8a is formed as a narrowed hole having a smaller diameter than the general part. The inlet of the discharge hole 8 communicates with an air oil supply path 13 provided from the housing 9 to the nozzle member 6. The air oil supply path 13 has an air oil supply port (not shown) in the housing 9 and a housing portion outlet 13 b on the inner surface of the housing 9. The housing portion outlet 13b communicates with an annular communication groove 13c provided on the outer diameter surface of the outer ring spacer 10, and each discharge of the nozzle member 6 is performed from the communication groove 13c through an individual path 13d that penetrates in the radial direction. It communicates with the hole 8. The air oil supply port of the air oil supply path 13 is connected to an air oil supply source (not shown) in which lubricating oil is mixed with compressed carrier air. A circumferential groove is provided around the inlet portion of the discharge hole 8 in the nozzle member 6 to provide a seal member 14 such as an O-ring, and the outer ring spacer 10 and the nozzle member 6 are connected to a fastening tool such as a bolt (not shown). ) To prevent air oil from leaking from the communicating portion between the air oil supply passage 13 and the discharge hole 8.

The operation of the air oil lubrication structure having the above configuration will be described. The air oil supplied to the air oil supply path 13 is injected through the discharge hole 8 of the nozzle member 6 onto the side wall surface 2 c of the circumferential groove 7 on the outer diameter surface of the boundary between the inner ring 2 and the inner ring spacer 11. The air oil injected to the side wall surface 2c of the circumferential groove 7 contributes to the lubrication of the bearing 1 in the following form.
(1) The lubricating oil adhering to the side wall surface 2c of the circumferential groove 7 is guided to the inner ring slope portion 2b by the surface tension and the component force to the large diameter side wall surface 2c generated by centrifugal force. Flows into the interior.
(2) The air oil staying in the circumferential groove 7 adheres to the inner surface of the rolling element 4 or the cage 5 from the inner ring inclined surface portion 2b and the tip portion 6aa of the nozzle member 6 and contributes as lubricating oil for each part of the bearing. (3) Even when the supply air becomes small and the flow becomes nonuniform on the circumferential groove 7, the negative generated in the gap δ between the inner ring slope portion 2 b and the annular flange portion 6 a of the nozzle member 6. Air oil flows into the bearing due to the pressure suction action and centrifugal force.

Thus, in this air oil lubrication structure, the lubricating oil can be stably supplied into the bearing, and the air oil is supplied directly into the bearing without injecting the air oil directly onto the raceway surface 2a of the inner ring 2, so that noise due to wind noise is reduced. Can be made.
In particular, since the circumferential groove 7 that receives the air oil injected from the nozzle member 6 is formed by combining the circumferential groove side wall surface 2c of the inner ring 2 and the chamfered portion 11a of the inner ring spacer 11, the bearing size Even when the size of the inner ring inclined surface portion 2b is small, the size of the circumferential groove 7 can be sufficiently secured. As a result, the shape and size of the flange-shaped portion 6a of the nozzle member 6 and the hole diameter of the discharge hole 8 can be taken into consideration in terms of cost and handleability, and additional parts or the like can be added, Stable lubrication with low noise is possible without using dimensions. As the small-diameter bearing 1, for example, a bearing having a bearing inner diameter of 50 mm or less is mainly targeted.
Further, not only when the bearing 1 is of a small diameter size, but for the purpose of increasing the load capacity, the roller length of the rolling element 4 made of cylindrical rollers is increased (for example, the roller length is 30 with respect to the bearing width). % To 50%), the inner ring slope portion 2b has a small size. Even in this case, the circumferential groove 7 having the above-mentioned combined structure enables stable lubrication with low noise without adding separate parts and the nozzle member 6 with a special shape and size. Become.

FIG. 3 shows another embodiment of the present invention. This air-oil lubrication structure for a rolling bearing is an angular ball bearing in the first embodiment shown in FIG. 1 in which the rolling bearing 1 is replaced with a cylindrical roller bearing. The inclined surface 2b of the inner ring 2 uses the step surface of one side portion (the bearing back side) of the outer diameter surface of the inner ring 2 as it is. A circumferential groove side wall surface 2c formed of a slope that is steeper than the slope portion 2b is formed on the width surface side of the slope portion 2b formed of the step surface. The rolling element 4 consists of a ball. Other configurations are the same as those in the embodiment of FIG.
In the angular ball bearing, since the step surface can be used for the inner ring slope portion 2b for supplying air oil in this way, the manufacturing is further simplified.

It is sectional drawing which shows the air oil lubrication structure of the rolling bearing concerning 1st Embodiment of this invention. It is a principal part expanded sectional view of the air oil lubrication structure. It is sectional drawing which shows the air oil lubrication structure of the rolling bearing concerning other embodiment of this invention. It is sectional drawing of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing 2 ... Inner ring 2a ... Raceway surface 2b ... Slope part 2c ... Circumferential groove side wall surface 6 ... Nozzle member 7 ... Circumferential groove 8 ... Discharge hole 11 ... Inner ring spacer 11a ... Chamfer-shaped part delta ... Gap

Claims (4)

  Provided on the outer diameter surface of the inner ring of the rolling bearing is a slope portion that follows the raceway surface of the inner ring, a nozzle member is provided along the slope portion with a gap, and the slope surface is located closer to the inner ring width surface side than the slope portion of the inner ring. A circumferential groove side wall surface comprising a slope that is steeper than the part, and forming a circumferential groove with the chamfered portion on the outer diameter side of the inner ring spacer adjacent to the inner ring and the circumferential groove side wall surface; An air-oil lubrication structure for a rolling bearing, wherein the nozzle member is provided with an air-oil discharge hole that opens to face the circumferential groove.   2. The air-oil lubrication structure for a rolling bearing according to claim 1, wherein the rolling bearing is a cylindrical roller bearing.   3. The rolling bearing according to claim 2, wherein the inner ring of the cylindrical roller bearing has a flange, and the inclined surface portion of the inner ring extends from the cylindrical surface portion adjacent to the raceway surface on the outer diameter surface of the inner ring flange to the width surface side. Air-oil lubrication structure.   2. The air-oil lubrication structure for a rolling bearing according to claim 1, wherein the rolling bearing is an angular ball bearing, and the slope portion of the inner ring is provided on the bearing back side.

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