JP2006234072A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing capable of stably moving lubricant from a clearance forming component to a ball, and capable of achieving high-speed, long service life and maintenance-free performance by using only the lubricant sealed in the bearing. <P>SOLUTION: This rolling bearing having an inner ring 1, an outer ring 2, and a plurality of balls 3 mounted between raceway faces 1a and 2a of the inner and outer rings 1 and 2 and held by a retainer 4 is provided with a lubricant reservoir forming component 6 and the clearance forming component 7. The lubricant reservoir forming component 6 is provided with a lubricant reservoir 8 inside, and kept into contact with the outer ring 2. The clearance forming component 7 is the member forming a clearance 14 communicating from the lubricant reservoir 8 to a part near the raceway face 2a of the outer ring 2 along a peripheral surface formed with the raceway face 2a, and is provided on the outer ring 2. An inside diameter surface 7aa of an end 7a of the clearance forming component 7 is shaped spherical. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing used for supporting a machine tool spindle or the like.

  As a lubrication method for machine tool spindle bearings, grease lubrication that can be used maintenance-free, air-oil lubrication in which lubricating oil is mixed with carrier air and oil is injected into the bearing from the nozzle, jet that injects lubricating oil directly into the bearing There are methods such as lubrication. In recent machine tools, in order to increase machining efficiency, there is a tendency for higher speed, and lubrication of main shaft bearings is also relatively inexpensive and air-oil lubrication that can be speeded up easily is often used. However, this air oil lubrication method has a problem from the viewpoint of cost, noise, energy saving, and resource saving because it requires an air oil supply device as ancillary equipment and requires a large amount of air. There is also a problem of deteriorating the environment due to the scattering of oil. In order to avoid these problems, recently, speeding up by grease lubrication has begun to attract attention, and requests have been increasing.

  Since grease lubrication is performed only with the grease enclosed at the time of bearing assembly, high-speed operation may lead to premature seizure due to deterioration of the grease due to bearing heat generation and oil film breakage on the raceway surface, especially the inner ring. . In particular, it is difficult to guarantee the grease life in a high-speed rotation region where the dn value exceeds 1 million (bearing inner diameter mm × rotational speed rpm).

New proposals have been introduced as a means of extending the life of grease. For example, there is a proposal (Patent Document 1) aiming at high speed and long life by providing a grease reservoir on the outer ring raceway surface portion. In addition, there is a proposal (Patent Document 2) in which a bearing is properly lubricated and lubricated by a grease reinforcing device provided outside the spindle.
Japanese Patent Laid-Open No. 11-108068 JP 2000-113998 A

However, the technologies of the above proposed examples are not satisfactory when considering the number of rotations used (> dn value 1.5 million) equivalent to air-oil lubrication and maintenance-free.
In order to solve such a problem, the applicant of the present invention has proposed a component that includes a lubricant reservoir forming component and a clearance forming component that forms a clearance that communicates from the lubricant reservoir to the vicinity of the raceway surface of the outer ring ( Japanese Patent Application No. 2003-424619). However, there is still room for improvement in the stability of the movement of the lubricating oil from the tip of the gap forming part to the ball.

  The present invention is intended to solve these problems, and it is a rolling bearing that can stably move the lubricating oil from the gap forming component to the ball, achieve high speed, long life, and maintenance-free. Is to provide.

  The rolling bearing according to the present invention is a rolling bearing having an inner ring, an outer ring, and a plurality of balls that are interposed between the raceway surfaces of the inner and outer rings and are held by a cage. A lubricant reservoir forming part provided in contact with the side raceway and forming a lubricant reservoir therein, and a gap provided in the fixed side raceway and communicating from the lubricant reservoir to the vicinity of the raceway surface of the fixed raceway And a gap forming part formed along the circumferential surface on which the raceway surface is formed, and the shape of the inner diameter surface of the tip of the gap forming part is a spherical shape. The spherical surface is, for example, a spherical surface along the rolling trajectory of the ball. The rolling bearing is, for example, an angular ball bearing.

The rolling bearing of this configuration is used by filling a lubricant reservoir with a lubricant, for example, grease when assembling the bearing. Lubricating oil in the lubricant filled in the lubricant reservoir is the tip of the gap forming part in the gap of the gap forming part due to capillarity that occurs in the gap and capillary action in the lubricant such as filled grease. Until. From the tip of the gap forming part to the ball, the ball moves to the ball by capillary action in a lubricant such as grease adhering to the raceway surface of the stationary side race. In this case, the lubricant can be supplied more stably when the moving distance is shorter. In this invention, since the shape of the inner diameter surface of the tip of the gap forming part is a spherical shape, the inner diameter of the tip of the gap forming part is secured while ensuring a distance that keeps the ball from contacting the tip inner diameter surface of the gap forming part and the ball. The surface can be brought close to the ball. Therefore, the lubricant in the lubricant pool is always supplied to the outer ring raceway surface stably from the gap forming part. This stable micro-lubrication makes it possible to increase the speed and life of rolling bearings and maintain maintenance.
The gap forming parts do not necessarily have to be provided on the entire circumference, but by providing them continuously on the entire circumference, the above-mentioned lubricating oil can be supplied from the entire circumference to the raceway surface of the fixed-side raceway, and the lubricity is excellent. I can do it. When the lubricant reservoir is also provided continuously over the entire circumference, it is excellent in supply capability of lubricating oil replenishment.

  In the present invention, a lubricant reservoir forming component may be disposed on one side of the raceway in the axial direction, and a seal for sealing the space between the inner ring and the outer ring may be provided on the other side. By providing the seal on the other side, the leakage of the lubricant from the inside of the bearing is prevented, and an even longer life is obtained.

In the present invention, the fixed-side race ring may be an outer ring, and the lubricant reservoir forming component may be provided on the inner diameter surface of the outer ring.
By disposing the lubricant reservoir forming part on the inner diameter surface of the outer ring, the bearing can be incorporated into the spindle device or the like with the lubricant filled in the lubricant reservoir, and the workability of the assembly is improved.

  In this invention, it is good also considering the ball | bowl side front-end | tip position of a lubricant reservoir formation component as the ball | bowl side rather than the edge part of a holder | retainer. The oil supply efficiency to the raceway surface is improved by positioning the tip of the lubricant reservoir forming component closer to the ball than the end of the cage.

In the present invention, the rolling bearing may be used for supporting a main shaft of a machine tool.
Machine tool spindles are strongly desired to be maintenance-free for high-speed rotation to improve machining efficiency, prevention of bearing heat generation to ensure machining accuracy, and productivity improvement by shortening operation stop time. Therefore, by using the rolling bearing of the present invention, the advantages of achieving high speed, long life, and maintenance-free by using only the lubricant filled in the lubricant reservoir in the bearing according to the present invention are effectively exhibited. Is done.

  The rolling bearing according to the present invention includes a lubricant reservoir forming component that is provided in contact with the fixed-side raceway and forms a lubricant reservoir therein, and a fixed-side raceway provided from the lubricant reservoir to the fixed-side raceway. A gap forming part that forms a gap communicating with the vicinity of the raceway surface along the circumferential surface on which the raceway surface is formed, and the inner diameter surface of the tip of the gap molding part has a spherical shape. Lubricating oil can be stably transferred from the formed part to the ball, and only the lubricant filled in the lubricant reservoir in the bearing can be used to achieve high speed, long life, and maintenance-free.

  A first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, this rolling bearing has a plurality of balls 3 interposed between raceways 1a and 2a of an inner ring 1, an outer ring 2, and inner and outer rings 1 and 2, and a lubricant reservoir forming component 6 on one end side; A gap forming part 7 is provided. The plurality of balls 3 are held by a cage 4, and the other end of the bearing space between the inner and outer rings 1 and 2 is sealed with a seal 5. This rolling bearing is an angular ball bearing, the seal 5 is provided at the end on the bearing back side, and the lubricant reservoir forming part 6 and the gap forming part 7 are provided on the bearing front side. On the front side of the bearing, the lubricant reservoir forming component 6 also serves as a seal, and lubricant leakage from the front side of the bearing is prevented. The lubricant here is grease.

The lubricant reservoir forming component 6 is a ring-shaped component having a lubricant reservoir 8 formed therein, and is provided in contact with the front side width surface of the outer ring 2. An inner ring positioning spacer 26 is disposed on the inner diameter side of the lubricant reservoir forming component 6, and a minute gap is formed between them.
In this example, the lubricant reservoir forming component 6 includes an outer ring positioning spacer 9 provided in contact with the front side width surface of the outer ring 2 and an outward groove shape fitted to the inner diameter surface of the outer ring positioning spacer 9. It consists of a lubricant reservoir forming component body 10. An internal space sandwiched between the outer ring positioning spacer 9 and the lubricant reservoir forming component main body 10 is used as the lubricant reservoir 8.

  The outer ring positioning spacer 9 has an engaging step 9a for fitting the tip of the side wall 10a of the lubricant reservoir forming component main body 10 at the end opposite to the outer ring 2 on the inner diameter surface. The lubricant reservoir forming component main body 10 is configured such that after the lubricant reservoir 8 is filled with the lubricant, the side wall portion 10a is engaged with the engaging step portion 9a of the outer ring positioning spacer 9, and the inner diameter surface of the engaging step portion 9a. By engaging a retaining ring (both not shown) with the retaining ring groove, the outer ring positioning spacer 9 is fixed in the axial direction. Between the outer diameter surface of the side wall portion 10a in the lubricant reservoir forming component body 10 and the engaging step portion 9a in the outer ring positioning spacer 9, and the adjacent portion between the outer ring positioning spacer 9 and the outer ring 2 in contact with the outer ring positioning spacer 9. Sealing parts such as an O-ring (not shown) are provided on the inner diameter surface, thereby preventing the lubricant from leaking.

  The gap forming part 7 is a ring-shaped part that forms a gap 14 that communicates from the lubricant reservoir 8 to the vicinity of the raceway surface 2a of the outer ring 2 along the circumferential surface on which the raceway surface 2a is formed. The gap forming part 7 is formed integrally with the lubricant reservoir forming part main body 10. That is, the lubricant reservoir forming component 10 is integrally extended from the outer diameter end portion of the side wall portion 10b on the bearing adjacent side.

As shown in an enlarged view in FIG. 2, in the angular ball bearing, the inner diameter surface 2 b of the outer ring counter bore portion on the front side is a tapered surface having a larger diameter on the width surface side from the ease of incorporation of the balls 3. The gap forming part 7 extends to the vicinity of the outer ring raceway surface 2a so as to form a gap 14 along the tapered surface 2b. The tip position of the gap forming part 7 on the ball 3 side is set to be closer to the ball 3 than the end of the cage 4. The shape of the inner diameter surface 7aa of the tip 7a of the gap forming part 7 is a spherical shape along the rolling locus of the ball 3. This inner diameter surface 7aa is not a spherical surface, but is a concave curved surface in which the shape of a cross section taken along an arbitrary plane including the bearing axis is an arc along the outer diameter surface of the ball 3.
Further, the outer diameter surface 7ab of the tip end portion 7a of the gap forming part 7 has a larger diameter than the outer diameter surface 7ba of the portion 7b up to the tip end portion 7a. Thereby, the clearance width of the clearance gap 14a in the front-end | tip part 7a of the clearance gap shaping | molding component 7 among the said clearance gap 14 is set narrower than the clearance width of the clearance gap 14b in the part 7ba to the front-end | tip part 7a.

The operation of the above configuration will be described. At the time of bearing assembly, the lubricant reservoir 8 is filled with a lubricant (grease). Lubricating oil in the lubricant filled in the lubricant reservoir 8 is passed through the tip 7a through the gap forming part 7 (a part of the gap 14b), and the tip 7a of the gap forming part 7 is narrow. It reaches the exit of the gap forming part 7 by the capillary phenomenon in the gap 14b.
From the tip of the gap forming part 7 to the ball 3, it moves to the ball 3 due to a capillary phenomenon in a lubricant such as grease adhered to the raceway surface 2 a of the outer ring 2. In this case, the lubricant can be supplied more stably when the moving distance is shorter. In this embodiment, since the shape of the inner diameter surface 7aa of the tip 7a of the gap forming component 7 is a spherical shape along the rolling locus of the ball 3, the inner diameter surface 7aa of the gap forming component 7 and the ball 3 are not in contact with each other. It is possible to bring the tip inner diameter surface 7aa of the gap forming component 7 closer to the ball 3 while ensuring a distance to maintain the distance. Therefore, the lubricating oil in the lubricant reservoir 8 is constantly supplied from the gap forming part 7 to the outer ring raceway surface 2a. This stable micro-lubrication makes it possible to increase the speed and life of rolling bearings and maintain maintenance.
In addition, since the tip of the gap forming part 7 on the ball 3 side is closer to the ball 3 than the end of the cage 4, the oil supply efficiency to the raceway surface 2a of the outer race 2 which is a stationary raceway is improved. To do.

  FIG. 3 shows an example of a spindle device for a machine tool using the rolling bearing of the above embodiment. In the spindle device for machine tools, two of the rolling bearings are used as a back surface combination. The two rolling bearings 23 and 24 rotatably support both ends of the main shaft 21 within the housing 22. The inner ring 1 of each rolling bearing 23, 24 is positioned by an inner ring positioning spacer 26 and an inner ring spacer 27, and is fastened and fixed to the main shaft 21 by an inner ring fixing nut 29. The outer ring 2 is positioned and fixed in the housing 22 by an outer ring positioning spacer 9, an outer ring spacer 30, and outer ring pressing lids 31 and 32. The housing 22 is formed by fitting a housing inner cylinder 22A and a housing outer cylinder 22B, and an oil passage groove 33 for cooling is provided in the fitting portion.

  The spindle 21 is provided with a chuck (not shown) for detachably attaching a tool or a work (not shown) to the front end 21a, and a drive source such as a motor transmits rotation to the rear end 21b. They are connected via a mechanism (not shown). The motor may be built in the housing 22. The spindle device can be applied to various machine tools such as a machining center, a lathe, a milling machine, and a grinding machine.

  According to the spindle device having this configuration, the rolling bearings 23 and 24 of this embodiment can effectively exhibit the effects of speeding up, extending the service life, and making maintenance free.

  FIG. 4 shows another embodiment of the present invention. In the rolling bearing of this embodiment, in the embodiment of FIG. 1, the oil passing material 12 is installed from the lubricant reservoir 8 of the lubricant reservoir forming part 6 to the gap 14b of the gap forming part 7, and the gap forming from the lubricant reservoir 8 is performed. The lubricating oil in the lubricant is guided to the part 7. As the oil-permeable material 12, for example, felt, paper, woven fabric, or the like can be used. Other configurations are the same as those of the embodiment of FIG.

  In this embodiment, since the lubricating oil in the lubricant filled in the lubricant reservoir 8 is sufficiently passed through the gap forming part 7 by the oil passing material 12, that is, to the gap 14b, the raceway surface of the outer ring 2 is obtained. The oil supply efficiency to 2a further improves.

  FIG. 5 shows still another embodiment of the present invention. In the rolling bearing of this embodiment, in the embodiment of FIG. 1, the lubricant pool forming component 6 </ b> A is disposed on the inner diameter surface 2 e of the outer ring 2, so that the lubricant pool 8 is placed inside the bearing space between the inner and outer rings 1 and 2. Is forming. In this example, the outer ring positioning spacer 9 in the example of FIG. 1 is not a component part of the lubricant reservoir forming component 6A, but is a single component corresponding to the lubricant reservoir forming component body 10 in the example of FIG. A forming component 6A is configured. The lubricant reservoir forming component 6A has an outward groove-shaped cross-sectional shape, and the gap forming component 7 is integrally provided. Other configurations are the same as those of the embodiment of FIG.

  In this embodiment, the length from the center of the raceway surface 2a of the outer ring 2 to the width surface on the bearing back side is made longer than the length on the bearing front side which is the arrangement side of the lubricant reservoir forming component 6A. The lubricant reservoir forming component 6A is fitted into the elongated outer ring inner surface 2e. In this case, the inner and outer rings 1 and 2 have the same width dimension, the width dimension is larger than the standard dimension in one direction, and the inner diameter surface 2e of the portion where the width dimension of the outer ring 2 is increased is as described above. The lubricant reservoir forming component 6A is fitted.

The portion of the inner diameter surface 2b following the raceway surface 2a of the outer ring 2 is a tapered surface in consideration of the assembling property of the ball 3 in the same manner as the angular ball bearing shown in FIG. The lubricant reservoir forming component 6A is fitted to the inner cylindrical surface 2e having a cylindrical surface shape. The internal space sandwiched between the inner diameter surface 2e and the lubricant reservoir forming component 6A is the lubricant reservoir 8.
A gap forming part 7 is integrally formed at the outer diameter end of the side wall 6b of the lubricant reservoir forming part 6A, and the gap forming part 7 is extended along the inner diameter surface 2b of the outer ring 2 to the vicinity of the raceway surface 2a. The gap 14 is formed and the width of the gap is the same as in the embodiment of FIG.
The side wall portion 6a outside the bearing of the lubricant reservoir forming component 6A is engaged with an engaging step portion 2f formed on the inner surface 2e of the outer ring, and the stopper is engaged with a retaining ring groove on the inner surface of the engaging step portion 2f. It is fixed in the axial direction by a ring (both not shown).

  The inner diameter surface of the inner ring 1 in the increased width dimension is a small diameter surface portion 1c having a smaller diameter than the portion of the inner diameter surface 1b adjacent to the raceway surface 1a. The lubricant reservoir 8 is widely secured by projecting the inner diameter portion of the lubricant reservoir forming component 6A toward the small diameter surface portion 1c. Other configurations are the same as those of the rolling bearing of FIG.

  In this embodiment, since the lubricant reservoir forming component 6A is disposed on the inner diameter surface 2e of the outer ring 2, the rolling bearing can be incorporated into a spindle device or the like in a state where the lubricant reservoir 8 is filled with the lubricant. . Therefore, the workability of the bearing assembly is improved.

  In each of the above embodiments, the case where the lubricant reservoir forming parts 6 and 6A and the gap forming part 7 are provided on the outer ring 2 side has been described. However, when the inner ring 1 is a stationary raceway, the inner ring 1 is lubricated. The agent reservoir forming parts 6 and 6A and the gap forming part 7 are provided.

It is a fragmentary sectional view of the rolling bearing concerning a 1st embodiment of this invention. It is a partial expanded sectional view of the rolling bearing. It is sectional drawing of the spindle apparatus for machine tools using the rolling bearing. It is a fragmentary sectional view of the rolling bearing concerning other embodiments of this invention. It is a fragmentary sectional view of the rolling bearing concerning other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 1a, 2a ... Raceway surface 3 ... Rolling body 4 ... Retainer 6, 6A ... Lubricant accumulation part 7 ... Gap molding part 7a ... Tip part 7aa of gap molding part ... Inner diameter surface 8 of tip part ... Lubricant reservoir 12 ... Oil-permeable material 14 ... Gap

Claims (6)

  In a rolling bearing having an inner ring, an outer ring, and a plurality of balls that are interposed between the raceway surfaces of these inner and outer rings and held by a cage, of the inner ring and outer ring that are the race rings, provided in contact with the non-rotating fixed side race ring A lubricant reservoir forming component having a lubricant reservoir formed therein, and a gap provided in the fixed-side raceway and communicating between the lubricant reservoir and the vicinity of the raceway surface of the fixed-side raceway. And a gap forming part formed along the peripheral surface, and the inner diameter surface of the tip part of the gap forming part has a spherical shape.   The rolling bearing according to claim 1, wherein the rolling bearing is an angular ball bearing.   2. The rolling bearing according to claim 1, wherein a lubricant reservoir forming component is disposed on one side of the raceway in the axial direction, and a seal is provided on the other side to seal a space between the inner ring and the outer ring.   The rolling bearing according to any one of claims 1 to 3, wherein the stationary side race ring is an outer ring, and the lubricant pool forming component is provided on an inner diameter surface of the outer ring.   The rolling bearing according to any one of claims 1 to 4, wherein a ball-side tip position of the lubricant reservoir forming component is on the ball side with respect to an end portion of the cage. 7. The rolling bearing according to claim 1, wherein the rolling bearing is used for supporting a main shaft of a machine tool.

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