JP2006022889A - Cylindrical roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical roller bearing in which the roundness and cylindricity of an inner ring orbit surface are successfully maintained, and an inner ring flange does not fall down into the orbit surface side of the inner ring flange, even when the inner ring is expanded in the radial direction by increasing the fitting force of the inner ring and a shaft. <P>SOLUTION: The cylindrical roller bearing 1 is provided with an outer ring 2, the inner ring 3, a roller 4 and a retainer 5. The inner ring 3 has an oil pathway 15 stretching from the inner diameter surface to the outer diameter side surface. The inner ring 3 has an orbit surface 31, an escape 32 located in the end of the orbit surface 31, a flange 34 having a flange surface 33 in contact with the end surface of the roller 4, a range A directly under the orbit surface located directly under the orbit surface 31, and a range B under the flange located under the flange 34. The oil pathway 15 is comprised of a vertical hole 15a extending from an oil inlet 11 installed in the inner surface of the inner ring 3 toward the radial direction in the range B under the flange, and a tilt hole 15b to connect an oil outlet 12 installed in the vertical hole and the escape 32. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a cylindrical roller bearing, and more particularly to a cylindrical roller bearing having an oil passage for lubrication in an inner ring.

  Japanese Patent Application Laid-Open No. 7-24687 (Patent Document 1) discloses a spindle device of a machine tool that employs an underlace lubrication system. Here, the under-lace lubrication method is a lubrication method in which lubricating oil is supplied into the bearing by centrifugal force through an oil passage formed in the inner ring. In the apparatus disclosed in Japanese Patent Laid-Open No. 7-24687, a ball bearing is used as a bearing for supporting the main shaft, and an oil passage that penetrates the inner ring in the radial direction is provided. Although not specifically described in this publication, a cylindrical roller bearing can be adopted as a bearing for supporting the main shaft instead of the ball bearing.

  FIG. 1 shows an example of a cylindrical roller bearing for underlace lubrication. A cylindrical roller bearing 1 shown in the figure includes an outer ring 2, a double collar type inner ring 3, rollers 4, and a cage 5. The inner ring 3 is provided with an oil passage 10 penetrating in the radial direction.

  FIG. 2 shows the inner ring 3 in an enlarged manner. As shown in the figure, the inner ring 3 includes a raceway surface 31, a relief portion 32 positioned at both ends of the raceway surface 31, a flange portion 34 having a flange surface 33 that contacts the end surface of the roller 4, and a position directly below the track surface 31. The area A directly below the raceway surface and the armpit area B located below the collar portion 34 are provided.

  In each drawing described later including FIG. 1 and FIG. 2, the same reference numerals and symbols indicate the same or equivalent elements.

  As shown in FIG. 2, the oil passage 10 extends radially in the underarm region B of the inner ring 3, has an oil inlet 11 on the inner ring inner diameter surface, and an oil outlet 12 on the outer diameter surface of the flange 34. have. A plurality of oil passages 10 are provided at intervals in the circumferential direction of the inner ring 3. In order to stably supply the lubricating oil (lubricant) to each oil passage 10, an oil groove 13 extending in the circumferential direction is formed on the inner diameter surface of the inner ring 3. The oil passage 10 that penetrates the underarm region B from the outer diameter surface of the flange portion 34 in the radial direction can be easily formed by drilling or the like.

  In order to improve the lubricating performance of the cylindrical roller bearing 1, it is necessary to supply sufficient lubricating oil between the end surface of the roller 4 and the flange surface 33 and between the outer peripheral surface of the roller 4 and the raceway surface 31. It is. However, the inner ring 3 having the structure shown in FIG. 2 cannot obtain good lubricating performance. FIG. 3 shows the flow of lubricating oil with arrows. As illustrated, the lubricating oil that has entered the oil passage 10 from the oil groove 13 is discharged from the oil outlet 12 of the flange 34 toward the inner diameter surface of the cage 5. The discharged lubricating oil is divided into a flow traveling toward the roller 4 and a flow traveling toward the outside of the bearing 1. Therefore, lubrication of the flange surface 33 and the raceway surface 31 tends to be insufficient. Considering the stable supply of lubricating oil to these parts, the amount of lubricating oil supplied to the oil passage 10 must be increased.

  Japanese Patent Laying-Open No. 2002-242943 (Patent Document 2) discloses a cylindrical roller bearing capable of solving the above-mentioned problems. FIG. 4 shows a cylindrical roller bearing 1 having substantially the same structure as that disclosed in this publication. The inner ring 3 of the cylindrical roller bearing 1 shown in the figure has an oil passage 14 that extends in a radial direction from a thin portion 32 positioned at both ends of the raceway surface 31 to an inner diameter surface. The oil outlet 12 of the oil passage 14 is exposed to the shading portion 32. An oil groove 13 extending in the circumferential direction is formed on the inner diameter surface of the inner ring 3 so as to overlap the oil inlet 11 of the oil passage 14.

In the case of the inner ring 3 having a structure as shown in FIG. 4, the lubricating oil is supplied to the thinning portion 32 located at the boundary between the raceway surface 31 and the flange surface 33, and therefore, between the end surface of the roller 4 and the flange surface 33, The lubricating oil can be stably supplied between the outer peripheral surface of the roller 4 and the raceway surface 31. In addition, it is easy to control the amount of lubricating oil supplied.
Japanese Patent Laid-Open No. 7-24687 JP 2002-242943 A

  In the inner ring 3 shown in FIG. 4, a plurality of oil passages 14 are provided at intervals in the circumferential direction. In order to supply the lubricating oil stably to the oil passage 14 by allowing axial displacement and circumferential displacement between the supply passage from the lubricating oil supply source and the oil passage 14, Groove processing or spot facing processing that overlaps the oil passage 14 is performed on the inner surface or the outer surface of the shaft. The groove or counterbore to be formed needs to have a groove width or counterbore diameter larger than the hole diameter of the oil passage 14.

  In the case of the inner ring 3 shown in FIG. 4, an oil groove 13 extending in the circumferential direction is formed with a groove width larger than the hole diameter of the oil passage 14. As is clear from FIG. 4, the oil groove 13 having a large groove width is located immediately below the shading portion 32 located at the boundary between the raceway surface 31 and the flange surface 33.

  Usually, the cylindrical roller bearing that supports the spindle of the machine tool is assembled so that the gap after assembly is about 0 μm in order to suppress the play of the spindle. In this case, the radial clearance is further reduced due to the temperature difference between the inner and outer rings during operation, resulting in a negative clearance (preload state). Under such usage conditions where high speed operation is performed with a negative clearance (preload state), it is important to prevent deterioration of the roundness and cylindricity of the raceway surface after the inner ring is assembled.

  In particular, in tapered roller type cylindrical roller bearings where the inner ring surface of the inner ring is tapered (taper hole angle 1/12 is the mainstream), in order to adjust the clearance after installation and to prevent creep, the inner ring should be Tighten and expand the inner ring in the radial direction. In this case, the raceway surface expands in the radial direction as the fitting force between the inner ring and the shaft increases.

  In the inner ring 3 shown in FIG. 4, an oil groove 13 having a large groove width is formed on the inner diameter surface located immediately below the relief portion 32. Further, the inner diameter surface is tapered. Therefore, when the fitting force between the inner ring 3 and the shaft is increased, both the flange portions 34 are expanded rather than the raceway surface 31 is expanded. As a result, it may be tightened more than necessary, or there is a concern that the collar 34 may fall to the track surface 31 side. Further, due to such influences, the roundness and cylindricity of the raceway surface after the inner ring expansion may be deteriorated.

  An object of the present invention is to maintain good roundness and cylindricity of the inner ring raceway surface even when the inner ring is radially expanded by increasing the fitting force between the inner ring and the shaft, and the raceway surface of the inner ring collar portion. It is to provide a cylindrical roller bearing that does not cause the side to fall down.

  The present invention is premised on a cylindrical roller bearing having an outer ring and an inner ring where the inner ring has an oil passage extending from the inner diameter surface to the outer diameter side surface. That is, the inner ring is located under the raceway surface, a corner portion located at the end of the raceway surface, a flange portion that contacts the end surface of the roller, a region directly below the raceway surface, and a bottom portion of the raceway surface. The oil passage includes a vertical hole extending in the radial direction from the oil inlet provided on the inner diameter surface of the inner ring and an oil outlet provided in the shank portion. Consists of inclined holes.

  According to the cylindrical roller bearing configured as described above, the oil inlet of the oil passage exposed on the inner diameter surface of the inner ring is located in the underarm region. Therefore, even if an oil groove and a counterbore are provided on the inner diameter surface of the inner ring so as to overlap with the oil inlet, they are located in the underarm region, not directly under the raceway surface. As a result, a sufficient fitting surface can be secured between the inner ring inner diameter surface in the region directly below the raceway surface and the shaft. Thus, according to the present invention, the roundness and cylindricity of the raceway surface are kept good even after the inner ring expands due to the increase in the fitting force between the inner race and the shaft, and the saddle portion is not tilted toward the raceway side. Don't make it happen.

  In one embodiment, the inner ring includes a pair of underarm regions on both sides of the region directly below the raceway surface, and oil passages are provided in each underarm region. In another embodiment, the inner ring is of a single flange type and has an oil passage in one armpit area.

  Preferably, the hole diameter of the vertical hole is larger than the hole diameter of the inclined hole. In this way, the lubricating oil can be stably supplied from the lubricating oil supply path into the vertical hole.

  In one embodiment, the inner diameter surface of the inner ring is formed in a tapered shape.

  5 and 6 show an embodiment of the present invention. In FIG. 6, the force acting on the inner ring inner surface when the inner ring and the shaft are fitted is indicated by an arrow.

  A cylindrical roller bearing 1 shown in the figure includes an outer ring 2, a double collar type inner ring 3, rollers 4, and a cage 5. The inner ring 3 has an oil passage 15 extending from the inner diameter surface to the outer diameter surface. The inner diameter surface of the inner ring 3 is tapered (taper angle 1/12).

  The inner ring 3 includes a raceway surface 31, a relief portion 32 positioned at both ends of the raceway surface 31, a flange portion 34 having a flange surface 33 that contacts the end surface of the roller 4, and a raceway surface located immediately below the raceway surface 31. A directly under area A and an underarm area B located under the underarm 34 are provided.

  As shown in the drawing, the oil passage 15 includes a vertical hole 15a extending in the radial direction from the oil inlet 11 provided on the inner diameter surface of the inner ring 3 and the oil provided in the vertical hole 15a and the shank portion 32. It is comprised by the inclination hole 15b which connects the exit 12. FIG.

  The vertical holes 15a and the inclined holes 15b can be easily formed by drilling or the like. With respect to the vertical hole 15a, after passing from the inner diameter surface of the inner ring 3 to the outer diameter surface of the flange portion 34, the outer diameter side portion of the flange portion 34 may be blocked. There is a concern that the material that has closed the hole will escape. Therefore, in the illustrated embodiment, the vertical hole 15a is not penetrated.

  The hole diameter of the vertical hole 15a is preferably larger than the hole diameter of the inclined hole 15b. If the vertical hole 15a has a large hole diameter, a slight positional deviation between the inclined hole 15b and the vertical hole 15a can be allowed. Further, the lubricating oil can be stably supplied from the lubricating oil supply path into the vertical hole 15a.

  A plurality of oil passages 15 are provided at intervals in the circumferential direction. In order to supply lubricating oil stably to these oil passages 15, an oil groove 13 extending in the circumferential direction is formed on the inner diameter surface of the inner ring 3 so as to overlap the oil inlet 11. The oil groove 13 is not located in the area A directly below the raceway surface, but is located in the armpit area B. Instead of the oil groove 13, a counterbore may be formed on the inner diameter surface of the inner ring 3 so as to overlap the oil inlet 11.

  FIG. 6 schematically shows the force acting on the inner diameter surface of the inner ring 3 when the inner ring 3 and the shaft (not shown) are fitted with each other by arrows, but in the illustrated embodiment, in the region A immediately below the raceway surface. A sufficient fitting surface can be secured between the inner ring inner surface and the shaft. Therefore, even after the inner ring 3 expands in the radial direction as the fitting force between the inner ring 3 and the shaft increases, the roundness and cylindricity of the raceway surface 31 can be kept good. Further, by positioning the oil groove 13 in the underarm region B, the area of the inner ring inner diameter surface located outside the oil groove 13 is reduced, and the magnitude of the force acting on this region is relatively reduced. . As a result, the collar portion 34 does not fall down toward the raceway surface 31 side.

  Since the lubricating oil sent out from the lubricating oil supply passage is discharged to the thinning portion 32 through the oil groove 13, the vertical hole 15 a and the inclined hole 15 b, between the end surface of the roller 4 and the flange surface 33 and the outer periphery of the roller 4. Lubricating oil can be stably supplied between the surface and the raceway surface 31.

  FIG. 7 shows another embodiment of the present invention. In this embodiment, no oil groove is formed on the inner diameter surface of the inner ring 3, and instead, an oil groove 21 extending in the circumferential direction so as to overlap the oil inlet 11 of the oil passage 15 on the outer peripheral surface of the main shaft 20. Is forming. The lubricating oil sent from the lubricating oil supply path is introduced into the oil groove 21 via the oil supply port 22 provided in the main shaft 21, and further passes through the oil passage 15 including the vertical hole 15a and the inclined hole 15b. Then, oil is supplied to a predetermined part.

  In the embodiment of FIG. 7, instead of the oil groove 21, a counterbore may be provided on the outer peripheral surface of the main shaft 20 so as to overlap the oil inlet 11 of the oil passage 15.

  In the illustrated embodiment, the double-sided type inner ring 3 is used, but the present invention is also applicable to a cylindrical roller bearing having a single-sided type inner ring. In this case, an oil passage including a vertical hole and an inclined hole is formed in one underarm region.

  In the illustrated embodiment, the inner ring surface of the inner ring is a tapered hole type cylindrical roller bearing, but the present invention is equally applicable to a normal cylindrical roller bearing that is not a tapered hole type. It is.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and changes can be made to the illustrated embodiment within the same range as the present invention or within an equivalent range.

  The present invention can be advantageously used particularly for a cylindrical roller bearing that supports the main shaft of a machine tool in an under-lace lubrication system.

It is sectional drawing which shows the conventional cylindrical roller bearing with an oil passage. It is sectional drawing which expands and shows the inner ring | wheel of the bearing shown in FIG. In the bearing shown in FIG. 1, it is the figure which showed the flow of the lubricating oil with the arrow. It is sectional drawing which shows the other example of the conventional cylindrical roller bearing with an oil passage. It is sectional drawing which shows the cylindrical roller bearing which concerns on embodiment of this invention. In the bearing shown in FIG. 5, when the inner ring and the shaft are fitted, the force acting on the inner surface of the inner ring is schematically shown by an arrow. It is sectional drawing which shows the cylindrical roller bearing which concerns on other embodiment of this invention.

Explanation of symbols

1 cylindrical roller bearing, 2 outer ring, 3 inner ring, 4 roller, 5 cage, 10 oil passage, 11 oil inlet, 12 oil outlet, 13 oil groove, 14 oil passage, 15 oil passage, 15a vertical hole, 15b inclined Hole, 20 main shaft, 21 oil groove, 22 oil supply port, 31 raceway surface, 32 shading part, 33 collar surface, 34 collar part, A area immediately below raceway surface, B armored area.

Claims (4)

In a cylindrical roller bearing comprising an outer ring and an inner ring, the inner ring having an oil passage extending from an inner diameter surface thereof to an outer diameter side surface,
The inner ring has a raceway surface, a corner portion positioned at the end of the raceway surface, a flange portion that contacts the end surface of the roller, a region directly below the raceway surface, and a position below the flange portion. And underarm area to
The oil passage includes a vertical hole extending in a radial direction from the oil inlet provided on the inner diameter surface of the inner ring, and an inclined hole connecting the vertical hole and an oil outlet provided in the shank portion. A cylindrical roller bearing comprising: The inner ring includes a pair of armpit regions on both sides of the region directly below the raceway surface,
The cylindrical roller bearing according to claim 1, wherein the oil passage is provided in each underarm region. The cylindrical roller bearing according to claim 1 or 2, wherein a hole diameter of the vertical hole is larger than a hole diameter of the inclined hole. The cylindrical roller bearing according to any one of claims 1 to 3, wherein an inner diameter surface of the inner ring is formed in a tapered shape.

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