JP2002266873A - Backing plate for raceway surface machining of inner and outer rings of bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance machining accuracy by increasing a frictional force between a workpiece supporting surface of a backing plate for transmitting a rotation of a workpiece and the workpiece, and use a diamond sintered body and a cubic boron nitride sintered body as material of the backing plate in inner and outer rings having small diameter, of a bearing, in a raceway surface machining of the inner and outer rings of the bearing. SOLUTION: The workpiece supporting surface of the backing plate 1 in a raceway machining device of the inner and outer rings of the bearing is formed of the diamond sintered body 10 or the cubic boron nitride sintered body, and the surface roughness of the workpiece supporting surface is 0.08 to 0.20 μm. A plurality of grooves 10a are formed in which an opening width of a surface is 0.05 to 0.50 mm and an accumulated opening area is within a range from 30 to 70% of a contact area with respect to the workpiece. The grooves cross each other so that a cross angle is within a range from 60 to 90 degrees inside the workpiece supporting surface. Accordingly, the frictional force between the supporting surface and the workpiece is enhanced to restrain slip of the workpiece and reduce a loss in rotation, thereby realizing the high machine accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for processing a raceway surface of an inner ring or an outer ring of a rolling bearing, which increases a frictional force between a workpiece support surface for transmitting rotation to the workpiece and the workpiece. The present invention also relates to a backing plate for machining raceway surfaces of bearing inner and outer rings.

[0002]

2. Description of the Related Art An apparatus for roughly grinding the raceway surface of an inner ring or an outer ring of a rolling bearing has a structure in which a disk-shaped rotary grindstone or a rotary grindstone with a shaft is machined while rotating the inner ring or the outer ring around an axis. Track surface processing apparatuses are known. In addition, as a device for super-finishing grinding, while rotating the inner ring or outer ring around the axis,
2. Description of the Related Art A track surface processing apparatus having a structure in which a stick-shaped grindstone is pressed against a track surface of an inner ring or an outer ring in a radial direction by pressure is known.

For example, Japanese Patent No. 2767926 discloses a super-finishing grinding device for an inner raceway surface, and Japanese Patent No. 2776725 describes a super-finishing grinding device for an outer raceway surface. FIG. 4A is a schematic diagram showing a super-finished grinding state of the inner raceway surface in such a processing apparatus, and FIG. 4B is a schematic diagram showing a super-finished grinding state of the outer raceway surface.

When the bearing inner ring raceway surface is subjected to super-finishing grinding, as shown in FIG.
1 is pressed against the raceway groove Ig of the inner ring I in the radial direction, and at the same time, the raceway groove Ig is processed while swinging the grindstone W1 in the arrow direction. Similarly, when the outer raceway surface is subjected to super-finishing grinding, the stick-shaped grindstone W1 is brought into radial contact with the raceway groove Og of the outer race O, as shown in FIG. Is processed in the direction of the arrow while machining the track groove Og.

FIG. 5 is a schematic view of a main part of a rough grinding apparatus for a raceway surface of a bearing outer ring, showing a mechanism for supporting a workpiece and transmitting rotation during machining. During the grinding process, the outer ring O is pressurized by the pressure roll R and pressed against the bearing surface of the backing plate B. At the same time, the outer periphery of the outer race O is supported by the shoe S. The main shaft A is driven to rotate the backing plate B, and the rotation is transmitted to the outer ring O.
Since the outer race O is pressed against the bearing surface of the backing plate B by the pressure roll R, the outer race O rotates together with the backing plate B, and the raceway groove Og is ground by the rotating grindstone W2 with the shaft. The bearing mechanism and the rotation transmitting mechanism of the inner and outer rings are almost the same both in the case of rough grinding of the inner raceway surface and in the case of super-finishing grinding of the raceway surface.

[0006]

When the track surface of a workpiece (outer ring or inner ring) is processed by a bearing mechanism and a rotation transmitting mechanism as shown in FIG. 5, the processing load applied to the workpiece from a grindstone depends on the processing load. A force that hinders rotation acts on the workpiece. Therefore, if the frictional force between the bearing surface of the backing plate B transmitting the rotation and the workpiece is insufficient,
A slip occurs between the two, and a loss occurs in the rotational force transmitted to the workpiece. When a loss occurs in the rotational force, the number of rotations of the workpiece becomes unstable, and the processing accuracy deteriorates or varies. This tendency becomes more remarkable as the contact area between the backing plate B and the workpiece decreases, that is, as the outer diameter of the workpiece decreases.

Extremely high processing accuracy is required for the raceway surface processing of the bearing inner and outer rings, and high precision is also required for the jig used for the processing. Conventionally, as a material constituting a workpiece support surface of a backing plate, mainly SKS steel, SUJ steel, SKD steel, SKH steel (all of which are J
Iron-based materials and cemented carbides such as IS standards have been used, but in recent years, as bearings have become more precise, sintered diamond and cubic boron nitride have excellent wear resistance with little deterioration in machining accuracy. Unity is used.

However, the diamond sintered body and the cubic boron nitride sintered body have a smaller friction coefficient with the SUJ steel, which is the material of the inner and outer races of the bearing, than the iron-based material and the cemented carbide, and therefore have a backing plate. When the bearing surface is formed of a diamond sintered body or cubic boron nitride sintered body, the frictional force between the bearing surface and the workpiece is reduced. For this reason,
Rotational loss is more likely to occur than when the bearing surface is made of an iron-based material or cemented carbide, especially for small-diameter bearing inner and outer rings with a small contact area with the bearing surface. There is a problem that a crystalline boron nitride sintered body cannot be used in some cases.

The problem to be solved by the present invention is to increase the frictional force between the workpiece support surface of the backing plate transmitting the rotation to the workpiece and the workpiece in the raceway surface machining of the bearing inner and outer rings. It is an object of the present invention to improve the accuracy and to make it possible to use a diamond sintered body or a cubic boron nitride sintered body as a backing plate material for a small-diameter bearing inner and outer rings.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a backing plate for an apparatus for machining a raceway surface of an inner ring or an outer ring of a rolling bearing, wherein a work bearing surface for transmitting rotation to the work is diamond sintered. And the surface roughness Ra of the support surface of the workpiece is set to 0.08 to 0.20 μm.

When the support surface of the workpiece of the backing plate is formed of a diamond sintered body or a cubic boron nitride sintered body, if the surface roughness of the support surface is small, the frictional force between the support surface and the workpiece is reduced. Will be insufficient. Conventionally, in order to prevent the surface of the workpiece from being damaged, even if the bearing surface is formed of a diamond sintered body or cubic boron nitride sintered body, the bearing surface is made of an iron-based material or cemented carbide. Surface roughness Ra as in certain cases
Was in the range of 0.01 to 0.05 μm. Therefore, when the bearing surface is formed of a diamond sintered body or cubic boron nitride sintered body having a smaller coefficient of friction than iron-based materials and cemented carbides, the frictional force between the bearing surface and the workpiece is insufficient. Rotation loss was easy to occur.

According to the research results of the present inventors, when the work supporting surface of the backing plate is formed of a diamond sintered body or a cubic boron nitride sintered body, the surface roughness Ra of the supporting surface is set to 0. It has been confirmed that by setting the thickness to 08 to 0.20 μm, the frictional force between the bearing surface and the workpiece can be improved without causing any damage on the surface of the workpiece. When the surface roughness Ra is less than 0.08 μm, the frictional force is insufficient, the workpiece slips and rotation loss occurs, and when the surface roughness Ra is more than 0.20 μm, the frictional force is sufficient, There is a risk of causing scratches on the surface of the object.

As described above, the surface roughness Ra of the work bearing surface
Is 0.08 to 0.20 μm, the frictional force between the bearing surface and the workpiece may be insufficient when the outer diameter of the workpiece is about 15 mm or less. In such a case, the frictional force can be increased by forming a groove in the bearing surface. This groove has a surface opening width of 0.05 to
A plurality of 0.50 mm grooves are formed so that the total opening area is in the range of 30 to 70% of the contact area with the workpiece. If the opening width of the groove is smaller than 0.05 mm, chips during processing are easily clogged, and processing accuracy is reduced. When the opening width of the groove is larger than 0.50 mm, the work interferes with attachment and detachment of the work, and the work is likely to be damaged or the groove to be easily damaged. If the ratio of the opening area of the groove to the contact area with the workpiece is smaller than 30%, the effect of improving the frictional force by the groove formation is not sufficient, and if it is larger than 70%, the holding area of the workpiece is small. There is a danger that the work may bite into the surface of the work and cause damage to the work.

Here, the grooves may be formed in parallel or radially in the bearing surface, or may be formed so that the grooves intersect. In the case of forming the crossing, if the crossing angle is smaller than 60 degrees, the strength of the bearing surface at the crossing portion is reduced and the defect is likely to occur, so the crossing angle is preferably set to 60 to 90 degrees.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a main part of an apparatus for rough-grinding a raceway surface of a bearing outer ring according to an embodiment of the present invention.
It is a figure which shows the mechanism which supports a workpiece at the time of a process and transmits rotation.

The essential parts of the machining apparatus of the present embodiment are the same as the essential parts of the machining apparatus shown in FIG. 5 except for the surface structure of the bearing surface of the backing plate 1. The main shaft 2 is driven while the outer periphery of the outer ring 4 is supported by the shoe 3 while being pressed by the roll 5 and pressed against the backing plate 1 which is a rotation transmitting body, and the backing plate 1 and the outer ring 4 are rotated to thereby provide a rotary grinding wheel with a shaft. 6, the track groove 4a is ground.

In this embodiment, the bearing surface of the cup-shaped backing plate 1 is formed of a ring-shaped diamond sintered body 10 having a thickness of 2 mm. The diamond sintered body 10 is obtained by sintering diamond particles having an average particle diameter of 10 μm together with a binder such as Co and Ni.

FIG. 2 shows a ring-shaped diamond sintered body 10.
3A is a front view, and FIG. 3B is a partially enlarged cross-sectional view. In the present embodiment, the surface roughness Ra of the surface of the diamond sintered body 10 is set to 0.08 μm, and the lattice-shaped grooves 10a are further formed. The opening width of the groove 10a is 0.15 mm and the depth is 0.05 mm, and the total opening area is formed so as to be about 50% of the contact area with the outer ring 4.

In this embodiment, since the bearing surface of the backing plate 1 is formed of the diamond sintered body 10, the wear resistance is excellent over a long period of time and the processing accuracy is less deteriorated. Further, the surface roughness Ra of the surface of the diamond sintered body 10 is set to 0.08 μm, and the lattice-shaped grooves 10a are formed on the surface.
The frictional force between the outer ring 4 and the outer ring 4 is increased, so that the outer ring 4 does not slip and rotation loss occurs, and high processing accuracy can be obtained.

The pattern of the grooves 10a formed on the surface of the diamond sintered body 10 is not limited to the example shown in FIG. 2, but may be various patterns. 3A and 3B are diagrams showing another pattern of the grooves on the bearing surface, wherein FIG. 3A shows an example in which the grooves are formed in parallel to a straight line, FIG.
(C) is an example in which the straight lines are obliquely crossed, and (d) is an example in which the lines are formed radially. In any case, the opening width of the groove 10a is 0.05 to 0.50 mm,
If the total opening area is formed so as to be within the range of 30 to 70% of the contact area with the workpiece, the diamond sintered body can be formed without causing the groove 10a to be damaged or causing any damage to the workpiece. The frictional force between the outer ring 10 and the outer ring 4 can be increased.

Although the above embodiment is an example of a rough grinding apparatus for a raceway surface of an outer ring of a bearing, a rough grinding apparatus for a raceway surface of an inner race is further provided with a super-finishing grinding apparatus for a raceway surface of an inner and outer race of a bearing. In the case of the above, the bearing surface of the backing plate can be formed of a diamond sintered body or a cubic boron nitride sintered body in the same manner, and can have a similar surface structure.

[Test Example] A backing plate of diamond sintered body (PCD) shown in FIG. 2 having a lattice-like groove formed on the bearing surface (Invention 1), cubic nitriding having grooves parallel to the bearing surface Backing plate of boron sintered body (PCBN) (Invention 2), backing plate of diamond sintered body having no grooves on the bearing surface (Invention 3), surface roughness Ra without grooves on the bearing surface A backing plate of a diamond sintered body having a thickness of 0.04 μm (Comparative product 1), a backing plate of a diamond sintered body having no groove formed on the bearing surface and having a surface roughness Ra of 0.25 μm (Comparative product 2); Using a backing plate (conventional product) with a cemented carbide bearing surface, the bearing inner ring raceway surface was super-finished. Table 1 shows the processing test results.

[0023]

[Table 1]

As can be seen from Table 1, in the case of comparative product 1 in which the bearing surface is a diamond sintered body and the surface roughness is the same as that of the conventional cemented carbide, the workpiece has a large slip and rotation loss is large. It was nearly twice that of the conventional product. In the case of the comparative product 2 whose surface roughness was too coarse, the rotation loss was small, but the workpiece was damaged. On the other hand, in the case of the inventions 1 to 3 in which the surface roughness is 0.10 μm in the diamond sintered body or the cubic boron nitride sintered body, the slip of the workpiece is suppressed, and the rotation loss is smaller than that of the conventional product. It was about 1/2 of the case. Further, when grooves were formed on the bearing surface, the effect of suppressing slippage was further improved.

[0025]

According to the track surface machining apparatus for the inner and outer races of the bearing,
The workpiece supporting surface of the backing plate that transmits rotation to the workpiece is formed of a diamond sintered body or cubic boron nitride sintered body, and the surface roughness Ra of the workpiece supporting surface is set to a specific range. Thereby, the frictional force between the bearing surface and the workpiece is increased, the slip of the workpiece is suppressed, the rotation loss is reduced, and high processing accuracy is obtained. Further, by forming a groove on the surface of the bearing surface, the frictional force can be further increased.

[Brief description of the drawings]

FIG. 1 is a schematic view of a main part of a rough grinding apparatus for a raceway surface of a bearing outer ring in an embodiment of the present invention.

FIG. 2 is a view showing a surface structure of a bearing surface of the backing plate shown in FIG. 1;

FIG. 3 is a diagram showing another pattern example of the groove on the bearing surface.

FIG. 4 is a schematic view showing a state of super-finishing grinding of the raceway surfaces of the inner and outer races of the bearing.

FIG. 5 is a schematic view of a main part showing a conventional example of a rough grinding device for a bearing outer ring raceway surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Backing plate 2 Main shaft 3 Shoe 4 Outer ring 4a Orbital groove 5 Pressure roll 6 Rotary grindstone with shaft 10 Diamond sintered body 10a Groove

Continued on the front page (72) Inventor Kenichiro Miyazaki 210 Takeno, Oji, Tanushimaru-cho, Ukiha-gun, Fukuoka Prefecture F-term in Noritake Diamond Co., Ltd. 3C034 AA13 BB71 CB07 DD20 3C049 AA03 AB06 CA01 CB06 3J101 AA02 BA51 DA12 FA44

Claims (3)

[Claims] 1. A backing plate for an apparatus for processing a raceway surface of an inner ring or an outer ring of a rolling bearing,
A workpiece support surface for transmitting rotation to the workpiece is formed of a diamond sintered body or a cubic boron nitride sintered body, and the surface roughness Ra of the workpiece support surface is 0.08 to 0.20 μm. Backing plate for machining raceway surfaces of bearing inner and outer rings. 2. A plurality of grooves having a surface opening width of 0.05 to 0.50 mm and a total opening area within a range of 30 to 70% of a contact area with the workpiece on the workpiece supporting surface. The backing plate for processing a raceway surface of an inner and outer race of a bearing according to claim 1, wherein the backing plate is formed. 3. The backing plate for machining a raceway surface of a bearing inner and outer race according to claim 2, wherein the plurality of grooves intersect within a range of 60 to 90 degrees in the bearing surface of the workpiece.