JP2003343569A - Processing method for finishing sliding surface in internal peripheral surface of outer race of bearing unit, and bearing unit applied therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit in which by smoothing its internal peripheral surface of an outer race using grinding or honing, and further finishing the internal peripheral surface using barrel finishing, the surface is smoothed and there occurs no burr and even if minute extraneous substances are attached after the processings, the substances are removed simply by wash with ease. <P>SOLUTION: The internal peripheral surface 1a of the outer race is made to contact a whetstone 8a of a grinding machine 8 to be ground and next the internal peripheral surface 1a that has been ground is processed by barrel finishing, so that there exists no burr and no minute extraneous substance in the internal of the peripheral surface 1a, which is thereby made further smooth. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in a bearing device used for a disk memory spindle motor such as a VTR drum spindle motor, an HDD motor, and other motors.

[0002]

2. Description of the Related Art The inner diameter surface of an outer ring which constitutes this type of bearing device is generally cut or ground.
That is, since the inner surface of the outer ring before machining has a large surface roughness and may have burrs and burrs, it is necessary to perform such cutting and grinding in order to eliminate the surface roughness and burrs and smooth the surface. It has been processed. The rolling surface of the rolling element is superfinished.
However, according to the cutting process or the grinding process, fine foreign matter such as fine chips and fine abrasive grains are generated by the working, so that the fine foreign matter may adhere to the concave portion of the rough surface. When adhered, it was difficult to remove even by washing. When this minute foreign substance rarely falls in the bearing state due to agitation of grease, etc. and is caught between the ball and the raceway surface, abnormal noise is generated or the surface is roughened to deteriorate the sound and reduce the acoustic life of the bearing. Could shorten the. Therefore,
As a technique to eliminate the harmful effects caused by such burrs and fine foreign matter remaining on the inner surface of the outer ring after cutting and grinding,
JP 2001-121416 and JP 2001-1240
94 and the like are disclosed.

[0003]

[Problems to be Solved by the Invention]
In 416, a finishing processing roller having a hardness higher than that of the outer ring is pressed against the inner diameter surface of the outer ring, so that the fine foreign matter adhered to the inner diameter surface of the outer ring is embedded in the inner diameter surface by the pressing of the finishing processing roller. A method of smoothly finishing the inner diameter surface is disclosed. On the other hand, Japanese Patent Laid-Open No. 2001-124
In 094, by passing a ball having a hardness larger than the inner diameter dimension and higher than the hardness of the outer ring through the inner diameter surface of the outer ring, fine foreign matter adhering to the inner diameter surface of the outer ring is pressed by pressing the large diameter ball. There is disclosed a method of embedding in the surface and finishing the inner diameter surface smoothly. However, in
1-121416 and Japanese Patent Laid-Open No. 2001-124094,
As described above, by using a finishing roller or a large-diameter ball, fine foreign matter attached to the inner diameter surface of the outer ring is forcibly embedded in the inner diameter surface. Or it was very difficult to scrape off and could not be done completely. Further, even if the fine foreign matter is forcibly embedded in the inner diameter surface, the foreign matter may drop from the inner diameter surface during use of the bearing.In such a case, the concave portion remains after the fine foreign matter is embedded. I will end up. Therefore, the purpose of completely removing burrs and fine foreign matters from the inner diameter surface of the outer ring to make the inner diameter surface smooth has not always been achieved. The present invention has been made in view of the above problems of the prior art, and an object thereof is to smooth the inner diameter surface of the outer ring by finishing by grinding or honing, and further finish the inner diameter surface with a barrel. Thus, it is possible to provide a bearing device that is smoother and has no burrs and can be easily dropped by washing even if a fine foreign matter adheres later.

[0004]

In order to achieve the above object, the present invention provides a bearing device in which a plurality of rolling elements are incorporated between an outer ring and an inner ring or a shaft, the inner surface of the outer ring Is finished by grinding or honing, and then barrel finishing is applied to the inner diameter surface of the outer ring. Further, as described above, the inner diameter surface of the outer ring is ground or honed, and then barrel finished to obtain a bearing device having a smooth inner diameter surface. An inner ring guide or a rolling element guide retainer may be incorporated in the bearing device. For example, in this case, a deep groove ball bearing using balls as rolling elements can be given as an example. Further, it is also possible to provide a bearing with a shaft provided with double-row raceway surfaces on the shaft, having outer rings corresponding to the respective raceway surfaces, and pre-loaded via a coil spring between the outer races. At this time, it is possible to incorporate a retainer for guiding the outer diameter surface of the shaft or the rolling element.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. The bearing device of the present invention is intended for all bearing devices in which a plurality of rolling elements are incorporated between an outer ring and an inner ring or between an outer ring and a shaft. This bearing device has a deep groove ball bearing, etc. incorporating a retainer for inner ring guide or rolling element guide, a double row raceway surface provided on the shaft, and an outer race corresponding to each raceway surface.
A bearing with a shaft preloaded between the outer rings via a coil spring may be used. At this time, a cage for guiding the outer diameter surface of the shaft or a rolling element guide may be incorporated. In the present embodiment, for the sake of explanation, a rolling bearing using balls as rolling elements is used.
The present invention is not limited to this, and a roller bearing or the like can be appropriately selected and changed within the scope of the present invention. Then, the inner diameter surface of the outer ring in the above bearing device is subjected to either grinding finish or honing finish, and then barrel finish. As described above, the inner surface of the outer ring is ground or honed to first reduce the surface roughness of the inner surface, and then the inner surface is barrel-finished to remain on the inner surface of the outer ring. By removing burrs and fine foreign matters, the inner diameter surface is made smoother.

FIG. 1 and FIG. 5 show an embodiment of a bearing with a shaft that has been subjected to a smooth surface finishing method for the inner diameter surface of the outer ring. 1 is an outer ring, 2 is a shaft having double-row grooves 2a, 3 is an outer ring 1 and a shaft 2
And a plurality of rolling elements 4 mounted between the outer rings 1, 1
A spring 5 disposed between them is a spring seat, and 6 is a sealing plate. Reference numeral 7 is a cage, which is a ball guide cage in the embodiment of FIG. 1 and a shaft outer diameter surface guide in the embodiment of FIG. Each of the above-mentioned components constituting the bearing device with a shaft has a well-known configuration except that the inner diameter surface 1a of the outer ring 1 is subjected to a unique smooth surface finishing treatment, and is not particularly limited and interpreted. The design can be changed within the range. FIG. 2 shows a state in which the inner diameter surface 1a of the outer ring 1 is ground and finished by using a desired grinding device 8. While rotating the outer ring 1 (direction R1 in the figure),
A grindstone 8a rotated at a high speed (R2 direction in the drawing) is pressed against the inner diameter surface 1a while traversing in the axial direction (S direction in the drawing) to finish the grinding. The grinding device 8 is not particularly limited, and a known device can be used. And FIG.
In (b), the state of the outer ring inner diameter surface 1a before the grinding finish is exaggeratedly enlarged, and as shown in FIG. 3 (b), the surface roughness of the inner diameter surface 1a is rough in the state before the grinding finish. Then, as shown in FIG. 2, grinding finish is performed, and then barrel finishing and bright barrel finishing are performed, and as shown in an exaggeratedly enlarged manner in FIG. 3 (c), the inner diameter surface 1a is a smooth surface without burr ( Smooth surface). The raceway surface 1b of the outer ring 1 is superfinished. FIG. 4 shows a state where the inner diameter surface 1a of the outer ring 1 is honed by using a desired honing machine 9, and the grinding wheel 9a of the honing head is rotated while pressing it against the inner diameter surface 1a (R3 direction in the figure). The honing is done by reciprocating in the axial direction (S1 direction in the figure). The honing machine 9 is the grindstone 9a in this embodiment.
Is configured to press the inner diameter surface 1a with the spring 9b.
It may be configured to pressurize with hydraulic pressure or the like, and known ones can be used without particular limitation. After finishing the honing in this manner, the inner diameter surface 1a is formed in the same manner as in the case of the grinding finish.
Barrel finishing and bright barrel finishing are performed, and the inner diameter surface 1a is finished to be a smooth surface (smooth surface) without burrs as shown in an exaggerated manner in FIG. 3 (c).

For the barrel finishing, a polishing process using a well-known barrel device or the like is appropriately selected, and a barrel having a relatively large margin for the purpose of removing burrs and rounding corners and a bright barrel for finishing the surface are combined. If it is carried out, more effect can be expected, but it is appropriately selected within the scope of the present invention without limitation. The selection and mixing ratio of the polishing stones (media), and various conditions such as the barrel rotation speed and the polishing time are appropriately set as necessary. In particular, in a shaft bearing in which a double row groove 2a is directly provided on the shaft 2 and preloaded by a spring 4 between the outer rings 1 and 1, the side where the balls 3 are assembled after both rows as shown in FIG. It is necessary to assemble the retainer 7 from the opposite side (shaft end side) of the spring 4 of the outer ring 1 (the upper side in the case of FIG. 1) because the spring 4 and the spring seat 5 interfere. For this reason, it is necessary to fill the grease G from the back surface (anti-pocket side) 7a of the retainer 7 at least at the side where the balls 4 are incorporated later. Therefore, since the grease G is filled through the gap between the cage outer diameter surface 7b and the outer ring inner diameter surface 1a, the cleanliness of the outer ring inner diameter surface 1a is greatly affected (in this case, the inner diameter surface 1a
If foreign matter is attached to a, raceway surface 1 together with grease G
It is conceivable that foreign matter may be pushed into b. ), The effect of the present invention can be expected. Furthermore, the effect can be expected with a bearing with a small shaft having a shaft diameter of 4 mm or less and the inner diameter of the outer ring 1 of 6.5 mm or less, and for smaller drum spindles such as DVC (digital video cassette recorder) and MICROMV (micro EMV). In this case, since lower torque is required and it rotates at a higher speed, it is unavoidable to lower the viscosity of grease and the like, and the oil film formation becomes thinner, so it is easily affected by the entrapment of extremely small foreign matter, and for high speed rotation. The shaft diameter used for this is 3 because it easily affects the sound.
The effect can be expected more with a bearing having a very small shaft having an outer ring inner diameter of 5 mm or less and a diameter of 5 mm or less.

[0008]

According to the present invention, since the inner surface of the outer ring is ground or honed and then barrel finished, the inner surface becomes very smooth, and burrs and burrs are eliminated, and fine foreign matter adheres later. Even if it is washed, it will be easy to drop. With bearings that incorporate cages for rolling element guides, cages for inner ring guides or shaft outer diameter surface guides, the cages do not come into contact with the inner diameter surface of the outer ring and slip, so conventionally the inner diameter surface of the outer ring is not ground. However, since the inner surface of the outer ring is finished by grinding or honing, and then barrel finishing, the adhered foreign matter can be easily removed by washing, and the effect of improving the cleanliness inside the bearing can be expected. In the case of a bearing device in which a double row raceway surface is provided on the shaft and outer races corresponding to each raceway surface are preloaded through a coil spring between the outer races, cleaning after mounting the bearing is easier than in single-row ball bearings. Although difficult in some cases, according to the present invention, even in the bearing device of such a form, since the inner diameter surface of the outer ring is ground and then barrel-finished, it is easy to clean.

[Brief description of drawings]

FIG. 1 is a sectional view of a bearing with a shaft which is an embodiment of a bearing device of the present invention.

FIG. 2 is a schematic cross-sectional view showing a state in which the inner diameter surface of the outer ring is finished by grinding.

3A is a cross-sectional view of an outer ring, FIG. 3B is an enlarged view exaggeratingly showing a state before grinding or honing the inner diameter surface of the outer ring, and FIG. 3C is grinding or honing the inner diameter surface of the outer ring. The enlarged view which exaggerates and shows the state after finishing and barrel finishing.

FIG. 4A is a schematic cross-sectional view showing a state where the inner diameter surface of the outer ring is finished by honing, and FIG. 4B is a schematic view of the state of FIG.

FIG. 5 is a cross-sectional view of a bearing with a shaft in which cages on both sides are assembled from both shaft end sides in another embodiment of the bearing device of the present invention.

[Explanation of symbols]

1: Outer ring 1a: inner diameter surface 2: axis 3: Rolling element 8: Grinding device 8a: Whetstone 9: Honing board 9a: whetstone

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3C058 AA02 CB01 CB03                 3J012 AB20 DB07 DB11 FB08 FB10                       HB01 HB02                 3J101 AA03 AA32 AA43 AA62 AA72                       BA22 BA53 BA54 BA55 DA11                       EA63 FA44 GA24

Claims (6)

[Claims] 1. A bearing device in which a plurality of rolling elements are incorporated between an outer ring and an inner ring or a shaft, wherein an inner diameter surface of the outer ring is ground or honed, and then the inner diameter surface is barrel-finished. A method of finishing the inner surface of the outer ring of the bearing device with a smooth surface, the method comprising: 2. A bearing device in which a plurality of rolling elements are incorporated between an inner ring or a shaft and an outer ring, wherein the inner surface of the outer ring is ground or honed and then barrel finished. A bearing device having a smooth surface. 3. The bearing device according to claim 2, wherein a cage for guiding the inner ring or rolling elements is incorporated. 4. A bearing device according to claim 2, which is a deep groove ball bearing in which a ball is used as a rolling element and a retainer for an inner ring guide or a ball guide is incorporated. 5. A bearing with a shaft, wherein a shaft is provided with a double-row raceway surface, an outer ring corresponding to each raceway surface is provided, and the shaft is preloaded via a coil spring between the outer races. The bearing device described. 6. The bearing device according to claim 5, wherein a cage for guiding the outer diameter surface of the shaft or the rolling element is incorporated.