JP3319489B2 - Method for evaluating the life of bearing balls - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sphere (ball) used for a ball bearing or the like by observing how a portion to be observed such as a defect on a surface of the sphere progresses by rotation of the sphere. The present invention relates to a method for evaluating the service life in a short time.

[0002]

2. Description of the Related Art In an angular ball bearing or a thrust ball bearing or the like, a ball interposed between an inner ring and an outer ring has a rolling groove of an inner ring and a rolling groove of an outer ring in a specific region (a stress circle of Hertz). ). Therefore, one or two annular running traces are formed on the surface of the ball as the ball rotates. In order for the inner and outer rings to rotate relative to each other with high precision, the surface of the ball must have few or small defects such as dents, dents, protrusions, corrosion, inclusions, alterations, etc. is necessary. This is because, if there is a defect on the surface of the sphere, the defect propagates as the sphere rotates and reduces the rotation accuracy of the ball bearing.

In order to track the progress of deterioration of a sphere due to a surface defect, the bearing is disassembled, the sphere is taken out, the state of the defect is observed, and then the axis of rotation of the sphere is made coincident with the direction of the axis before taking out. Incorporated in the bearing. Next, after rotating the bearing, the ball is taken out, the progress of the defect is observed, and the process of assembling the ball again with the direction of the rotation axis coincident may be repeated. This method may seem simple in theory, but it is extremely difficult in practice. The reason is that, unlike a roller bearing in which a rotation axis is fixed, in the case of a ball bearing, the relative positional relationship between the ball and the rotation axis is not uniquely determined. For example, the rotation axis changes as the rotation speed changes until the end of rotation or the start of rotation. Therefore, once disassembled, it is impossible to predict in which portion the running trace will be formed in the next rotation test.
For this reason, the defect of the ball does not always come into contact with the inner ring or the outer ring every time the ball rotates, and even if the ball rotates, the ball does not easily progress from the defect as a starting point, and it takes time to evaluate the life of the ball.

The present invention has been made in consideration of the above-mentioned problems of the prior art,
In a short time, the life of defects due to the rotation of the ball
In addition, the object of the present invention is to provide a method that can accurately evaluate the ball, so that the ball is always rotated around the rotation axis in the same direction in a state where the defect of the ball is surely located in the running trace (in a state of being held). I decided that. The present invention has been experimentally known that, when a hole is provided in the surface of a ball of a ball bearing and the ball is rotated, a line connecting the hole and the center of the ball automatically becomes a rotation axis of the ball. (NSK Technical Journal No.
651 (published in 1991)) to make an unbalanced sphere by making a hole in the surface of the ball to be tested at one place toward the center of the sphere.

[0005]

In order to achieve the above object, 1) According to the first aspect of the present invention, an annular traveling object in which an observation target portion is wound on the surface of a sphere by contact with an inner ring or an outer ring. Set the rotation axis of the sphere in the relationship arranged in the trace, provide a hole toward the center of the sphere on the surface of the sphere on the rotation axis, incorporate the sphere between the inner ring and the outer ring, rotate the ball bearing Each time the ball rotates, the observation target portion is brought into contact with the inner ring or the outer ring, and the ball is deteriorated and propagated in a short time. 2) According to the second aspect of the invention, the ball bearing having the same dimensions as the sphere having the observation target portion and incorporating the sphere having no observation target portion is rotated, and the inner ring or the outer ring is formed on the surface of the sphere having no observation target portion. Wraps an annular running trace due to the contact, and transfers a transfer circle having the same diameter as the annular running trace on the surface of the sphere including the observation target portion, and the center of the transfer circle and the center of the sphere including the observation target portion A hole facing the center of the sphere provided with the observation target part is provided on the surface of the sphere including the observation target part, so that the straight line passing through becomes the rotation axis of the sphere, and the sphere including the observation target part is interposed between the inner ring and the outer ring. The present invention is characterized in that the ball bearing is rotated, the observation target portion is brought into contact with the inner ring or the outer ring each time the ball rotates, and the ball is deteriorated and propagated in a short time. 3) According to the third aspect of the present invention, a ball bearing having the same dimensions as the sphere having the observation target portion and having no observation target portion incorporated between the inner ring and the outer ring is rotated to provide the sphere without the observation target portion. A line connecting a point on a circle formed on the surface of the sphere with a center line drawn on the surface of the sphere by a center line drawn in the width direction center of the running trace on the surface of the sphere by winding an annular running trace due to contact with the inner ring or the outer ring. Is determined, a cone angle that includes a straight line connecting the center of the sphere through the observation target portion of the sphere having the observation target portion is determined, and a rotation axis that is equal to the cone angle is determined. Drill a hole toward the center of the sphere at the intersection of the rotation axis and the surface of the sphere,
A ball provided with an observation part is interposed between the inner ring and the outer ring to rotate the ball bearing, and the object to be observed is brought into contact with the inner ring or the outer ring every time the ball rotates, thereby causing the ball to deteriorate and evolve in a short time. Features. 4) According to the fourth aspect of the present invention, the ball bearing incorporating the ball to be observed is rotated to wind an annular running trace due to contact with the inner ring or the outer ring on the surface of the ball, and the running trace is formed on the running trace. An observation target portion is provided at an arbitrary position, and the center of the circle formed on the surface of the sphere is connected to the center of the sphere by the center line in the width direction of the annular running trace to obtain the rotation axis, and the rotation axis and the surface of the sphere are obtained. Drill a hole at the intersection with the center of the sphere, rotate the ball bearing,
Each time the ball rotates, the observation target is brought into contact with the inner ring or the outer ring, and the ball is deteriorated and developed in a short time.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS.
This will be described based on FIG. This is the angular contact ball bearing 10 of FIG.
This is an example in which the defect is used as an observation target portion, and when the surface of the ball has a defect as an observation target portion, the defect is always included in the running trace. First, as shown in FIG. 2, a ball (hereinafter, abbreviated as “defective ball”) 10 having a predetermined diameter D and having a defect (observation target portion) 12 at one place on the outer surface,
The bearing 1 is designed to always rotate around the same rotation axis XX.
00, the defect 12 is
8 or the running trace 16 formed by contact with the rolling groove 114 of the outer ring 104.

For this purpose, as shown in FIG. 3, a normal ball (hereinafter, abbreviated as “normal ball”) 20 having the same diameter D as the defective ball 10 and having no observation object portion on the outer surface is prepared. It is installed between the inner ring 102 and the outer ring 104 of the angular contact ball bearing 100, and the two wheels are relatively rotated while the load and the number of rotations are constant. Then, normal ball 2
At 0, an annular running trace 22 is formed by contact with the rolling groove 108 of the inner ring 102, and an annular running trace 24 is formed by contact with the rolling groove 114 of the outer ring 104. Inner ring 102
Hertzian stress circles 109 and 115 are formed on the rolling groove 108 and the rolling groove 114 of the outer ring 104, respectively. Here, a reference circle 26 (having a diameter Da) is determined on the center in the width direction by using the running trace 22 of the inner ring having a high stress in the central portion, and the reference circle 26 includes the defect 12 on the defective ball 10. Transfer as follows.

For this purpose, as shown in FIG. 4, an annular transfer ring 30 made of a wire and having a diameter Da is prepared (a plurality of rings having slightly different diameters are prepared, and the transfer rings 30 are individually placed on the balls 20). The transfer ring 30 is coated with a paint or the like to cover the defective ball 10 with the scratch 12 as shown in FIG. Then, as shown in FIG.
A transfer circle 32 having a diameter Da is drawn on the surface of the defective ball 10.

Thereafter, a straight line XX connecting the center point Oa and the center point O of the defective ball 10 is determined with reference to the transfer circle 32 of the defective ball 10 as shown in FIG.
This is the required rotation axis. In determining a straight line based on the center points Oa and O, for example, as shown in FIG.
A base 35 having a reference hole 36 having the same diameter as the transfer circle 32
The transfer circle 32 is placed so as to coincide with the periphery of the reference hole 36,
The detection member 38 is lowered vertically from above. If the point A where the detecting member 38 first contacts at that time is marked, a straight line from this point A toward the center of the defective ball 10 becomes the rotation axis XX to be obtained. Next, as shown in FIG. 7, a hole 34 is formed in the portion where the rotation axis XX intersects the surface of the ball 10 toward the center of the defective ball 10. Then, as described above, under the condition that the load and the number of rotations are constant, the defective ball 10 is taken out of the bearing 100 and re-mounted.
Even when it is incorporated in the rotation axis 0, it always rotates around the rotation axis XX. Therefore, since the defect 12 is always located within the running trace 14, the defect 12 becomes a starting point, and the defective ball 10 deteriorates and develops in a short time.

In FIG. 3, the running trace 1 of the outer ring 104 is shown.
The transfer ring can also be made by using the transfer rings 6 and 24 (in this case, the diameter of the transfer ring 30 is different from that in the above embodiment). In the above embodiment, the present invention is used for an angular contact ball bearing. However, the present invention can be applied to other types of bearings such as a thrust ball bearing. The running trace formed on the surface of the normal ball may be one depending on the type of bearing used.

Next, a second embodiment in which the present invention is applied to a pure thrust ball bearing will be described with reference to FIGS.
As shown in FIG. 9, the thrust ball bearing 80 includes an inner ring 82,
It comprises an outer ring 84 and a ball 60 interposed between the two wheels. The inner ring is rotated by incorporating the normal ball 60 into this bearing. Then, as shown in FIG.
The running trace 62 is formed on the surface of the
However, the running traces 64 are respectively formed by the contact with the rolling grooves of the outer ring 84 (note that the rotation axis is not horizontal but inclined at a certain angle with respect to the horizontal direction when the inner ring of the pure thrust ball bearing rotates. Can also do two).

Here, using a running trace 64 formed by contact with the outer ring 84, as shown in FIG. 11, a circle 6 formed on the surface of the ball 60 by its center line in the width direction as shown in FIG.
A cone angle formed by a line 69 connecting the point 68 on 6 and the center O of the ball 60 is determined. Next, as shown in FIG.
Defective ball 70 having a defect (observation target portion) 72 on the surface
Is determined, and a straight line 78 passing through the center O of the defective ball 70 is determined so that the cone angle of the straight line 73 connecting the defect 72 and the center O is equal to the cone angle. is there.

Then, as shown in FIG. 13, a hole 79 is made on the rotation axis XX of the defective ball 70, the defective ball 70 is assembled into the bearing 80, the bearing 80 rotates, the defective ball 70 is removed, The life of the defective ball 70 is evaluated by repeatedly observing the defect 72. In the first embodiment, the rotation axis XX is obtained on the surface of the defective ball 10 by using the transfer circle 32. In the second embodiment, the defective ball 7
Axis of rotation X using a cone angle connecting the defect 72 of zero and the center O
-X.

Next, a third embodiment will be described with reference to FIGS. In this method, a running track is first formed on a normal ball, and then a defect is artificially formed in the running track. More specifically, as shown in FIG. 14, a normal ball 90 is assembled between the inner ring 82 and the outer ring 84 of the thrust ball bearing 80 shown in FIG. 9, and the bearing 80 is rotated to form a running trace 92 on the surface of the normal ball 90. , 94 are formed. afterwards,
The ball 90 is defined by the center line of the running trace 94 in the width direction.
A defect (for example, an observation target portion due to a dent) 96 is artificially formed on a circle 95 formed on the surface. Next, if the center Ob of the circle 95 and the center O of the normal ball 90 are connected by a straight line,
This straight line becomes the desired rotation axis XX. Then, a hole 99 is formed in the shape of the rotation axis XX toward the center of the sphere. According to this method, it is convenient to observe the deterioration progress by the observation target part artificially attached to a normal ball later. still,
It goes without saying that the present invention can be appropriately changed and improved in addition to the above-described embodiments within a range not to impair the gist of the present invention.

[0015]

As described above, according to the first aspect of the present invention, the object to be observed comes into contact with the inner ring or the outer ring each time the ball rotates, so that the ball can be rapidly deteriorated and developed from this point. . As a result, the life of the sphere can be easily and accurately evaluated within a short time. In the invention of claims 2 and 3,
To determine the rotation axis of the sphere with the observation target part on the surface, first form a running trace on the surface of the sphere without the observation target part, use this to determine the rotation axis of the sphere with the observation target part, Drill a hole where the axis of rotation meets the surface of the sphere. As a result, the ball rotates even before the ball is taken out of the bearing and after the ball is re-mounted, with the observation target portion always in contact with the inner ring and the outer ring. As a result, the observation target portion rapidly deteriorates and advances, so that the life of the sphere can be easily and accurately evaluated within a short time.

According to the fourth aspect of the present invention, the ball is previously rotated in the bearing to form a running trace on the surface, and an artificial defect is formed on the running trace. Thereafter, a hole was provided on a straight line connecting the center of the circle formed by the running trace and the center of the sphere, and the straight line automatically became the rotation axis of the sphere.
Thereby, it is most suitable for observing the deterioration starting from the artificial defect, and the life of the sphere can be evaluated within a short time.

[Brief description of the drawings]

FIG. 1 is a front view of an angular ball bearing using a first embodiment of the present invention.

FIG. 2 is a front view of a defective ball to be subjected to life evaluation.

FIG. 3 is a front view of a defect-free ball used for life evaluation.

FIG. 4 is a perspective view of a transfer ring.

FIG. 5 is an explanatory diagram for explaining a process of evaluating the life of a defective ball.

FIG. 6 is an explanatory diagram for explaining a life evaluation process of a defective ball.

FIG. 7 is an explanatory diagram for explaining a life evaluation process of a defective ball.

FIG. 8 is an explanatory diagram for explaining a life evaluation process of a defective ball.

FIG. 9 is a front view of a pure thrust ball bearing using the second embodiment.

FIG. 10 is a front view of a defect-free ball used for life evaluation.

FIG. 11 is an explanatory diagram for explaining a life evaluation process of a defective ball.

FIG. 12 is a front view of a defective ball to be subjected to life evaluation.

FIG. 13 is an explanatory diagram for explaining a life evaluation process of a defective ball.

FIG. 14 is an explanatory diagram in which a running trace is formed on a ball used in the third embodiment.

FIG. 15 is an explanatory diagram illustrating a process of obtaining a rotation axis.

[Explanation of symbols]

 10, 70... Defective ball 12... Defect 14, 16,... Running trace 20, 60..., Defect-free ball 22, 24, 62, 64. ········································································ Transfer circle Holes 80, 100 ... Bearings 82, 102 ... Inner ring 84, 104 ... Outer ring

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16C 19/00-19/56 F16C 33/30-33/66 G01M 13/04 G01B 5/00

Claims (4)

(57) [Claims] 1. A method for evaluating the life of a ball by observing the progress of deterioration with rotation starting from an observation target portion on the surface of a ball interposed between an inner ring and an outer ring of a ball bearing. The rotation axis of the sphere is set in a relationship that the observation target portion is arranged in an annular running trace wound on the surface of the sphere by contact with the inner ring or the outer ring, and the rotation axis on the rotation axis Provide a hole on the surface of the sphere toward the center of the sphere, incorporate the sphere between the inner ring and the outer ring, rotate the ball bearing, and move the observation target part with the inner ring or the outer ring each time the sphere rotates. A method for evaluating the life of a bearing ball, wherein the ball is brought into contact with the ball for deterioration and development in a short time. 2. A method for evaluating the life of a ball by observing the progress of deterioration with rotation starting from an observation target portion on a surface of a ball interposed between an inner ring and an outer ring of a ball bearing. In, by rotating a ball bearing incorporating a sphere having no observation target portion with the same dimensions as the sphere having the observation target portion, the surface of the sphere without the observation target portion has an annular shape by contact with an inner ring or an outer ring. A running trace is wound, and a transfer circle having the same diameter as the annular running trace is transferred to the surface of the sphere including the observation target portion. The center of the transfer circle and the center of the sphere including the observation target portion are transferred. A hole facing the center of the sphere is provided on the surface of the sphere including the observation target portion so that a straight line passing therethrough is the rotation axis of the sphere, and the sphere including the observation target portion is interposed between the inner ring and the outer ring. The ball bearing is rotated by mounting, and the observation target portion is The contacting with the inner or outer ring, the evaluation method of the life of the ball bearing, characterized in that degradation progress in a short time 該玉. 3. A method for evaluating the life of a ball by observing the progress of deterioration with rotation starting from an observation target portion on the surface of a ball interposed between an inner ring and an outer ring of a ball bearing. In the ball provided with the observation target portion in the same dimensions as the ball provided with the observation target portion, a ball bearing incorporated between the inner ring and the outer ring is rotated, and the surface of the ball not provided with the observation target portion is rotated. A line connecting the center of the sphere and a point on a circle formed on the surface of the sphere by a center line drawn at the center in the width direction of the running trace is wound around an annular running trace due to contact with the inner ring or the outer ring. Finding the included cone angle, Finding a rotation axis such that a cone angle that includes a straight line passing through the observation target portion of the sphere provided with the observation target portion and connecting to the center of the sphere is equal to the cone angle, Drill a hole toward the center of the sphere at the intersection of the rotation axis and the surface of the sphere, A ball provided with the observation target portion is interposed between the inner ring and the outer ring to rotate the ball bearing, and the rotation of the ball causes the observation target to come into contact with the inner ring or the outer ring, thereby shortening the ball. A method for evaluating the life of a bearing ball, characterized in that the ball is deteriorated over time. 4. A method for evaluating the life of a ball bearing by observing the progress of deterioration associated with rotation starting from an observation target portion on the surface of a ball interposed between an inner ring and an outer ring of a ball bearing. In the above, a ball bearing incorporating a ball to be observed is rotated to wind an annular running trace on the surface of the ball by contacting the inner ring or the outer ring, and the observation target is positioned at an arbitrary position on the running trace. A part is provided, a rotation axis is obtained by connecting a center of a circle formed on the surface of the sphere and a center of the sphere by a center line in a width direction of the annular running trace, and a rotation axis is obtained. Drilling a hole toward the center of the sphere at the intersection, rotating the ball bearing, contacting the object to be observed with the inner or outer ring each time the sphere rotates, and causing the ball to deteriorate and develop in a short time. Characteristic evaluation method for the life of bearing balls.