JP2003148478A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing capable of receiving a radial load, axial loads in both directions, and a moment load and suppressing a spin sliding between rolling elements and raceway grooves and reducing a torque by lowering a rolling resistance. SOLUTION: A plurality of rolling elements 5 are incorporated between the outer ring 1 and the inner ring 2, the outer ring 1 and the inner ring 2 comprise raceway grooves having raceway surfaces larger in radius than the rolling elements 5, and at least either of the outer ring 1 and inner ring 2 comprises two raceway surfaces. The rolling elements 5 are formed in a ball shape having an outside diameter 5a forming a rolling contact surface with a curvature also in axial direction and having at least one flat surface 5b. The plurality of rolling elements 5 are disposed on a circumference in intersected state, and the outside diameters 5a of the rolling elements always come into contact with the raceway surface of the outer ring 1 and the raceway surface of the inner ring 2 opposed to each other at a total of two points. Only the areas of the rolling elements near the contact part of the rolling surface with the raceway track raceway surface are finished with a specified roughness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing capable of receiving a radial load, an axial load in both directions, and a moment load, for example, industrial machinery, robots, medical equipment, semiconductor / liquid crystal manufacturing equipment, optics and optoelectronics. Used in devices, etc.

[0002]

2. Description of the Related Art Conventionally, one bearing that can receive a radial load, an axial load in both directions, and a moment load is a cross roller bearing shown in FIG. 20, a four-point contact ball bearing shown in FIG. 21, and a bearing shown in FIG. Three-point contact ball bearings are known.

[0003]

However, in the cross roller bearing, the rolling element is the roller 300, and the rolling element 300 and the bearing ring (the inner ring 100 and the outer ring 200) are in line contact at two places, so that the moment rigidity is large. While having advantages, there is a problem that torque and torque fluctuation are large. In the four-point contact ball bearing or the three-point contact ball bearing, the rolling element is the ball 400,
Since the rolling element 400 and the races (inner ring 100, outer ring 200) are in point contact at four or three points, they have the advantages of low torque and smooth operation, but also have low moment rigidity and large ball spin. There is a problem that spin wear performance cannot be obtained.

The present invention has been made in view of the above problems of the prior art, and its object is to:
To provide a rolling bearing capable of receiving a radial load, an axial load in both directions, and a moment load, which realizes a reduction in torque by reducing rolling resistance as well as suppressing spin slip between a rolling element and a raceway groove.

Further, according to the present invention as set forth in claim 1, in the rolling bearing which achieves the first object, the roughness is adjusted only in the vicinity of the contact portion of the rolling surface of the rolling element with the raceway surface of the race. It has a secondary purpose. Further, according to the present invention as set forth in claim 2 and claim 3, in the rolling bearing for achieving the first object, an edge portion is not provided at a joint portion between the rolling surface and the flat surface portion of the rolling element. It has a secondary purpose.

[0006]

In order to achieve the above object, the technical means of the present invention is to incorporate a plurality of rolling elements between a pair of bearing rings, wherein each of the bearing rings has a radius greater than that of the rolling elements. Each of the rolling elements has a raceway groove having a large diameter raceway surface, at least one raceway ring has two raceway surfaces, and each rolling element has an outer diameter serving as a rolling contact surface which also has a curvature in the axial direction. A raceway surface of one raceway ring and a raceway surface of the other raceway that have at least one plane and are arranged alternately in a cross shape on the circumference, and the outer diameters of the rolling elements are always opposite to each other. There is a total of two points in contact with each,
The predetermined roughness is provided only in the vicinity of the contact portion between the rolling surface and the raceway surface of the rolling element.

A plurality of rolling elements are incorporated between a pair of races, and each of the races has a raceway groove formed of a raceway having a diameter larger than the radius of the rolling body, and at least one raceway has two raceways. Each rolling element is composed of a raceway surface, and each rolling element has an outer diameter serving as a rolling contact surface that also has a curvature in the axial direction and has at least one flat surface, and a plurality of rolling elements are alternately arranged in a cross shape on the circumference. Together, the outer diameter of each rolling element is always in contact with the raceway surface of one raceway ring and the raceway surface of the other raceway ring, one point each, for a total of two points. In addition, it is a smooth circular arc shape that is continuous from the rolling surface to the flat surface, and the apex of the circular arc is the contact point with the raceway surface.

A plurality of rolling elements are incorporated between a pair of races, and each race has a raceway groove formed of a raceway having a diameter larger than the radius of the rolling body, and at least one raceway has two raceways. Each rolling element is composed of a raceway surface, and each rolling element has an outer diameter serving as a rolling contact surface that also has a curvature in the axial direction and has at least one flat surface, and a plurality of rolling elements are alternately arranged in a cross shape on the circumference. Together, the outer diameters of the rolling elements are always in contact with each other on the raceway surface of one raceway ring and the raceway surface of the other raceway wheel at two points in total, respectively. That is, the connecting portion has a smooth arc shape with at least one curvature.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the rolling bearing of the present invention will be described below with reference to the drawings. The present embodiment is merely an embodiment disclosed in the description of the rolling bearing of the present invention and is not limited in any way, and can be freely modified within the scope of the present invention.

FIG. 1 shows the first embodiment, FIG. 11 shows the second embodiment, and FIG. 16 shows the third embodiment. It should be noted that each embodiment is merely a specific embodiment of the rolling bearing of the present invention, and should not be construed as being limited thereto.

In the "first embodiment" rolling bearing, a plurality of rolling elements 5, 5 ... Are provided in a raceway groove 3 formed between the inner diameter of the raceway ring (outer ring) 1 and the outer diameter of the raceway ring (inner ring) 2. It is built in. The bearing rings 1 and 2 are formed in the inner diameter of one bearing ring (outer ring) 1 and the outer diameter of the other bearing ring (inner ring) 2 by the respective raceway surfaces 1a, 1b, 2a, 2b having a desired shape. 3 is formed and either one or both of the bearing rings 1 and 2 is axially divided into two in the center in the width direction, or the type in which neither of the bearing rings 1 and 2 is divided. Used. Also, the two-split type is
Some can be assembled together with rivets.

The raceway groove 3 is formed by raceway surfaces 1a, 1b, 2a, 2b having a radius larger than that of the rolling element 5. If the raceway surfaces 1a, 1b, 2a, 2b have a shape suitable for rolling of the rolling element 5,
The cross-section may be arched, V-shaped, or any other shape, and may be curved or straight, but is not particularly limited. For example, a Gothic arch or the like is applied.

In this embodiment, the bearing ring (outer ring) 1
And the orbital ring (inner ring) 2 respectively have two orbital surfaces 1a and 1b.
And 2a · 2b, but at least one race ring (either the outer ring 1 or the inner ring 2) has two raceway surfaces (1a · 1b or 2a · 2b), the scope of the present invention It is within.

The rolling element 5 has at least one flat surface, an outer diameter 5a serving as a rolling surface (rolling contact surface) has an axial curvature, and each of the raceway surfaces 1a.1b, 2a.2b. The rolling element 5 has an arbitrary shape having a radius smaller than the radius, and the rolling elements 5 are arranged such that adjacent rolling elements 5 are alternately arranged in an intersecting manner, and the outer diameter 5a of each rolling element 5 is always one of the races. 1
Raceways 1a and 1b and the raceways 2b and 2 of the other race 2
Two points are in contact at a.

For example, the rolling element 5 is, as shown in FIG.
Upper and lower cut balls having two planes (also referred to as a pair of relative surfaces) 5b, 5b
5b refers to a structure having a structure. same as below. ), The respective rolling elements 5, 5 ... Are incorporated so that the rotation center axes 5c perpendicular to the planes 5b, 5b are intersected with each other, and the outer diameter 5a of each rolling element 5 is always one of the orbits. The raceways 1a and 1b of the wheel 1 and the raceways 2b and 2a of the other race 2 are in two-point contact.

The upper and lower cutting widths of the rolling element 5 are not particularly limited, and the upper and lower cutting ratios may be equal or unequal, and can be arbitrarily selected within the scope of the present invention. Further, instead of the parallel and symmetrical planes 5b, 5b, two non-parallel planes may be provided and a rotation center axis 5c perpendicular to the planes may be provided (not shown).

Further, the rolling element (upper and lower cut balls) 5 having two asymmetrical parallel planes 5b and 5d shown in FIG. 4 is used, and the surface 5d which is the large end side of the planes 5b and 5d is a bearing. By arranging the rolling element 5 so as to face the inner ring 2, the rotation of the rolling element 5 becomes more stable and lower torque can be realized. It is especially used for high speed rotation. It should be noted that it is within the scope of the present invention if the planes 5b and 5d of this rolling element are made non-parallel.

Further, each rolling element 5 described above has two flat surfaces 5
b, 5b (5d) having a ball shape, but having only one plane 5b in which only one of the upper and lower sides is cut to a desired width and having a rotation center axis 5c perpendicular to the plane 5b It may be a ball-shaped rolling element (Fig. 5).

The overall shape of the rolling element 5, flat surfaces 5b, 5b
The presence / absence of (5d), the magnitude of the curvature in the outer diameter 5a in the axial direction, and the like are not limited to the above specific shapes, and can be arbitrarily changed within the scope of the present invention.

Further, when the rolling elements 5, 5 ... Are incorporated, the rotation center axes 5c, 5c of the adjacent rolling elements 5, 5 are alternately crossed, and the crossing states are orthogonal or non-orthogonal. Any of the shapes may be used.

The method of arranging the rolling elements 5 in an intersecting manner is not particularly limited as long as the number is the same in both cases, that is, the rolling elements 5 may intersect every one. Even if they do not intersect, if they are the same in both numbers, they may intersect each other, such as two, one, one, two, etc., and both are within the scope of the present invention.

Further, in this embodiment, the raceway raceway surface 1a (1b, 2a, 2b) of the rolling element rolling surface (outer diameter) 5a.
The predetermined roughness was set only in the vicinity of the contact portion with and the roughness was not specified particularly in other ranges. As described above, the rolling element 5 has "the outer diameter 5a serving as the rolling contact surface has a curvature in the axial direction" as well. In other words, the rolling contact surface 5a of the rolling element 5 has a single R dimension. It has a spherical shape.
From this, it is considered that the same grinding method as that of the rolling element (ball) of the ball bearing can be adopted as the method of manufacturing the rolling element (see FIG. 8). In this polishing method, as shown in FIG. 8, R-shaped grooves 13a and 14a, which are slightly larger than the rolling elements 5, are formed on the end faces of the disk-shaped fixed plate 13 and grindstone 14, respectively, and a plurality of R-shaped grooves 13a and 14a are formed. By arranging the rolling elements 5 and sandwiching them between the fixed plate 13 and the grindstone 14 and rotating the grindstone 14, the rolling elements 5 can be randomly rotated and uniformly polished. However, the rolling element 5 has, for example, a drum shape obtained by crushing a part of a sphere, and when the rolling element 5 is polished by the above method, the flat surface 5b is formed.
Because of this, it does not rotate randomly within the grindstone 14, and only the rolling direction of the rolling element 5 is easily polished, and the grindstone 1
Since only the width where 4 contacts is polished, the entire rolling surface 5a is not uniformly polished. Also, if time is spent, rolling surface 5a
Although it is possible to polish the entire surface, the cost increase is inevitable. Specifically, it is as follows. A description will be given based on FIGS. 6 and 7.

The rolling bearing is the raceway surface 1 of the race 1 (2).
The curvature of a (1b, 2a, 2b) is equal to the rolling surface 5 of the rolling element 5.
Since it is slightly larger than the curvature of a, the contact form is point contact like the ball bearing, and the contact ellipse Y is formed at the contact portion X. In the above bearing, the rolling element has a constant rotating shaft 5c, and the rolling ellipse major axis 5 of the rolling surface 5a is 5
The range other than a'is never in contact with the raceway surface 1a. Therefore, it is necessary to improve the roughness of the rolling surface 5a only within the range of the contact ellipse major axis 5a '.
In other ranges, it is not necessary to specify roughness. However, in reality, since it is necessary to consider the skew associated with the spin, the range that defines the roughness is defined by the contact ellipse major axis 5
If it is made slightly wider than a ', it will not cause any problem in the function of the bearing. The ratio (b / D) of the diameter D of the rolling element 5 to the range b defining the roughness was 0.02 to 0.5. In addition,
In this embodiment, the roughness is 0.01 μmRe. An appropriate range may be selected as the range for defining the roughness depending on the number of rolling elements, the curvature ratio between the raceway surface 1a (or 1b, 2a, 2b) and the rolling surface 5a, and the magnitude of the load.
In addition, within the range that can be processed without increasing the cost, b
The value of / D may be selected in advance. In this way, by defining the rolling surface roughness only within the range of the major axis of the contact ellipse,
As with the balls in ball bearings, polishing can be performed, which has the effect of suppressing cost increases.

The movement of each rolling element 5, 5 is guided by a cage 6 or a separator (spacer) 8. Cage 6,
The separator (spacer) 8 is not particularly limited as long as it has the pockets 6 b for holding and guiding the rolling elements 5 or the grooves 9 and 9 and is arbitrarily selected and changed within the scope of the present invention. It is possible. The guide system of the cage 6 is not particularly limited, and may be inner ring guide, outer ring guide, or rolling element guide. Further, the structure of the cage 6 is not particularly limited, and may be an integral type or one formed from several parts.

A typical example of the retainer 6 is a machined retainer (annular retainer) 6 shown in FIG. 9. The retainer 6 has adjacent rolling elements 5 and 5 rotating around a central axis 5c. ，
Pockets 6b, which can be alternately assembled so that 5c are crossed, are arranged on the circumference of the annular body 6a in the same quantity as the number of rolling elements 5 ... It is configured. Both side surfaces 6c, 6d in the axial direction of each pocket 6b are alternately parallel and are neither perpendicular nor parallel to the rotation axis of the bearing, and have a constant angle (inclined shape) at the same level as the contact angle of the rolling element 5. ing.

Both side surfaces 6c in the axial direction of each pocket 6b.
The distance between 6d is configured to be slightly larger than the width of the rolling element 5. If the pocket 6b has inclined parallel side surfaces 6c and 6d and the distance between the side surfaces 6c and 6d is formed to be slightly larger than the width of the rolling element 5, the pocket 6b will have the same shape. The overall shape is not particularly limited and can be changed within the scope of the present invention. In the present embodiment, the same number of pockets 6b as the number of rolling elements 5 ... Are arranged at equal intervals and alternately in a cross shape on the circumference, but the number of rolling elements 5 is not particularly limited. If they are the same, they may intersect each other, or may intersect each other such as two, one, two, etc., and are within the scope of the present invention.

Due to the influence of various factors, spin or skew may occur in the rolling element that is rotating. If the posture of the rolling element cannot be controlled well, the rolling resistance of the bearing becomes large and the rolling element rotates smoothly. It may not be possible. Therefore, the pocket 6b of the cage 6 is provided with parallel side surfaces 6c and 6d which are substantially the same as a constant angle of the same level as the contact angle of the rolling element 5.
With c and 6d, the posture change of the rolling element 5 due to the spin, skew, etc. of the rolling element 5 is suppressed, and the posture of the bearing can be maintained, so that the torque of the bearing can be reduced.

The separator 8 has a diameter smaller than the diameter of the rolling element 5, and has a concave shape for holding the rolling elements 5 and 5 which are adjacently held so that the central axes 5c and 5c of the rolling elements are in a cross shape as described above. The arc grooves 9 and 9 are formed in a cross shape on the relative surfaces 10 and 10. The curvature of the arc groove 9 may be substantially the same as or larger than the curvature of the rolling element outer diameter 5a, and may be arbitrary. Such a structure allows the bearing to be more compact.

The state in which the preload is applied between the rolling element and the raceway surface is not particularly limited, that is, the preload may or may not be applied during the manufacturing stage and is within the scope of the present invention. .

Bearing steels 1 and 2 and rolling elements 5 of these bearings are usually made of bearing steel, but stainless steel, ceramics or the like are used to improve corrosion resistance and heat resistance depending on the operating environment. It is selected appropriately. Further, as the material of the cage 6, a machined cage, a press cage, a resin cage or the like is appropriately selected. Therefore, for example, metal such as brass or iron, or polyamide 66 (nylon 66) / polyphenylene sulfide (PPS) is used. ) And other synthetic resins are selected within the scope of the invention.

Therefore, according to the present embodiment, the raceway surface 1a of the outer ring 1 and the raceway surface 2b of the inner ring 2 where the outer diameter 5a of the rolling element 5 faces each other make point contact with each other (contact points are indicated by 11, 11). ,
The adjacent rolling elements 5 make point contact with each other (the contact points are shown as 12, 12) on the raceway surface 1b of the outer ring 1 and the raceway surface 2a of the inner ring 2. Since the contact angles of the rolling elements 5 and 5 intersect alternately, a single bearing can receive a radial load, an axial load in both directions, and a moment load. The rolling element 5 is the raceway surfaces 1a and 2b, and the other rolling element 5 is the raceway surfaces 1b and 2b.
Point contact at 2 points each with a (11/11/12/12)
Since it does not, the large spin in the conventional four-point contact bearing can be eliminated.

Further, since the contact type between the rolling elements 5 and 5 and the outer and inner rings 1 and 2 is the same as that of a general ball bearing, rolling resistance is lower than that of a cross roller and low torque can be realized.

[Second Embodiment] This embodiment is a rolling bearing used particularly in a special environment such as a vacuum or a corrosive environment, and the bearing has substantially the same structure as the bearing described in the first embodiment. However, the rolling element 5 is configured using a ceramic sintered body typified by silicon carbide or silicon nitride. The bearing structure other than the rolling elements 5 and the main operation effects other than the operation effects peculiar to the present embodiment are the same as those of the above-described first embodiment, and therefore description thereof will be omitted.

The rolling element 5 is formed in a ball shape having at least one flat surface using a ceramic sintered body typified by silicon carbide or silicon nitride, and the edge of the connecting portion 5e between the rolling surface 5a and the flat surface 5b is formed. It is eliminated and has a smooth arc shape continuous from the rolling surface 5a to the flat surface 5b, and the apex 5f of the arc is the contact point with the raceway surface 1a (1b, 2a, 2b). That is, when a ceramic sintered body typified by silicon carbide or silicon nitride is used, when the rolling member 5 has the edge portion 5g at the connecting portion 5e between the rolling surface 5a and the flat surface 5b, a shock acts. At this time, there is a possibility that the edge portion 5g of the rolling element 5 may be cut off, and if broken pieces are caught in the rolling contact surface, the function as a bearing is likely to be impaired. Therefore, as in the present embodiment, the connecting portion 5e between the rolling surface 5a of the rolling element 5 and the flat surface 5b.
By eliminating the edge portion 5g of the rolling element 5 and forming a continuous smooth arc shape from the rolling surface 5a to the flat surface 5b, even if the rolling element 5 is made of a ceramic sintered body, when the rolling element 5 is impacted, It is possible to prevent breakage of the joint portion 5e between the rolling surface 5a and the flat surface 5b, and to exhibit stable performance for a long period of time. In addition, the apex 5f of the circular arc is connected to the raceway surface 1a (1b / 2a
Even at the contact point with 2b), since these arcs are smoothly continuous, the function as the rolling contact surface is not impaired. Specifically, it is as follows.

FIG. 12 shows an example in which a smooth circular arc continuous from the rolling surface 5a to the flat surface 5b of the rolling element 5 is an elliptic arc r1 having a major axis equal to the width w1 of the rolling element. Ratio: a / b is in the range of 0.5 to 1.0. The effect is that the rolling surface 5a of the rolling element 5 and the edge portion 5g of the connecting portion 5e of the flat surface 5b have a smooth elliptic arc shape, so that even if the rolling element 5 is made of a ceramic sintered body, an impact is not generated. It becomes difficult for the rolling element 5 to be chipped when it acts.

FIG. 13 shows a smooth circular arc which is continuous from the rolling surface 5a of the rolling element 5 to the flat surface 5b, which is equal to the width w1 of the rolling element.
This is an example of a single arc r2 having a radius of / 2, and
And b: a / b, or b and a in the figure: b /
a is a / b = b / a = 1.0. The effect is that the rolling surface 5a of the rolling element 5 and the edge portion 5g of the connecting portion 5e of the flat surface 5b have a smooth single arc shape,
Even if the rolling element 5 is made of a ceramic sintered body, the rolling element 5 is less likely to be chipped when an impact is applied.

FIG. 14 shows an example in which a smooth arc continuous from the rolling surface 5a of the rolling element 5 to the plane 5b is an elliptic arc r3 having a width w1 of the rolling element as a minor axis. ratio:
b / a is in the range of 0.5 to 1.0. The function and effect are similar to those of the example shown in FIG.

In FIG. 15, the rolling element 5 has one flat surface, and a smooth circular arc continuous from the rolling surface 5a to the flat surface 5b is 1 / the same width as the width w1 of the rolling element shown in FIG. 2 is an example of an elliptic arc r4 having a major axis of 2, and the ratio of a to b in the figure: a / b is in the range of 0.5 to 1.0. The function and effect are similar to those of the example shown in FIG.

In this embodiment, as described above, FIG.
Although the elliptic arc r4 having a major axis equal to 1/2 of the width w1 of the rolling element shown in FIG. 4 is used, it is also possible to adopt the arc configuration shown in FIGS.

[Third Embodiment] This embodiment has substantially the same structure as the bearing described in the first embodiment, but at least one connecting portion 5e between the rolling surface 5a and the flat surface 5b of the rolling element 5 is provided. It was decided to form a smooth arc shape with the above curvature. The bearing structure other than the rolling elements 5 and the main operation effects other than the operation effects peculiar to the present embodiment are the same as those of the above-described first embodiment, and therefore description thereof will be omitted.

The rolling element 5 has a ball shape having at least one flat surface, and the connecting portion 5e between the rolling surface 5a and the flat surface 5b has a smooth arc shape with at least one curvature. The rolling element 5 is a two-plane surface 5 cut at the upper and lower sides with a desired width
A configuration having b and 5b, a configuration having one plane 5b obtained by cutting either the upper or lower side, or the like is adopted. That is, when the connecting portion 5e of the rolling surface 5a of the rolling element 5 and the flat surface 5b has an edge shape, wear of the cage 6 progresses at the contact portion with the cage 6 due to long-term use. As a result of the large pocket clearance, there is a problem that the effect of suppressing the skew of the rolling element 5 is lost and the torque becomes large. If the configuration of the present embodiment is adopted, the connecting portion 5e of the rolling surface 5a and the flat surface 5b of the rolling element 5 is formed into a smooth arc shape with at least one curvature, so that the contact portion with the retainer 6 is locally formed. Dynamic contact is suppressed, cage wear is suppressed, and stable torque performance can be exhibited for a long time under radial load, axial load, and moment load conditions. Specifically, it is as follows.

FIG. 17 shows the rolling surface 5a and the flat surface 5 of the rolling element 5.
The connecting portion 5e of b has a single R dimension (r5) and has a smooth arc shape. This effect is obtained by connecting the rolling surface 5a and the flat surface 5b of the rolling element 5 which has been conventionally edge-shaped.
By making e a smooth arc shape, local contact in the contact with the cage 6 is softened, and cage wear is suppressed.

FIG. 18 shows the rolling surface 5a and the flat surface 5 of the rolling element 5.
The connecting portion 5e of b has two different R dimensions (r6, r7)
It has a smooth and circular arc shape.
It is similar to the case of FIG.

Further, although not shown, a plurality of, for example, three connecting portions of the rolling surface and the plane of the rolling element may be formed into a smooth circular arc shape with different R dimensions. It is similar to the case of. Further, not limited to these, a smooth circular arc continuous from the rolling surface to the flat surface may be an elliptic arc whose major axis is the width of the rolling element.

FIG. 19 shows that the rolling element 5 has one flat surface 5b, and the connecting portion 5e between the rolling surface 5a of the rolling element 5 and the flat surface 5b has a single R dimension (r8) and has a smooth arc shape. It is what The function and effect are similar to those in the case of FIG. Further, the arc configuration shown in FIG. 18 or the arc configuration in which the connecting portion between the rolling surface and the plane of the rolling element is formed into a smooth arc shape with a plurality of different R dimensions may be applied.

[0046]

According to the present invention, since it has the above-mentioned structure, one bearing can receive a radial load, an axial load in both directions, and a moment load. Further, according to the present invention, the following effects can be obtained in addition to the above effects. Since each rolling element is always in two-point contact with the raceway groove of the bearing ring, it is possible to suppress an increase in torque due to a large spin of balls in the conventional four-point contact bearing. Further, since the outer diameter of the rolling element serving as the rolling contact surface is formed with a curvature also in the axial direction, the rolling resistance is lower and the torque can be reduced as compared with the cross roller.

According to the present invention as set forth in claim 1,
In addition to the above-mentioned operational effects, the following operational effects are also exhibited. Since the rolling surface roughness is specified only in the range of the major axis of the contact ellipse, even if the rolling element has at least one flat surface,
As with the rolling elements of conventional ball bearings, polishing can be performed,
It has the effect of suppressing the cost increase.

According to the second aspect of the present invention, the following action and effect are obtained in addition to the above-mentioned action and effect. As in the present invention, by eliminating the edge of the connecting portion between the rolling surface and the plane of the rolling element and forming a continuous smooth arc from the rolling surface to the flat surface, the rolling element is made of a ceramic sintered body. Also,
When an impact is applied, it is possible to prevent breakage of the joint between the rolling surface and the flat surface of the rolling element, and to exhibit stable performance over a long period of time. Further, even if the apex of the arc is the contact point with the raceway surface, since these arcs are smoothly continuous, the function as the rolling contact surface is not impaired. According to the present invention described in claim 3, in addition to the above-described action and effect, the following action and effect are also exhibited. According to the present invention, the rolling surface of the rolling element and the connecting portion of the flat surface are formed into a smooth arc shape with at least one or more curvatures, so that the local contact in contact with the cage is softened and the cage wears. Can be suppressed, and stable torque performance can be exhibited for a long period of time under radial load, axial load, and moment load conditions.

[Brief description of drawings]

FIG. 1 is an overall sectional view showing a first embodiment of a rolling bearing of the present invention with a part thereof omitted.

FIG. 2 is a sectional view showing a part of the rolling bearing of the first embodiment.

FIG. 3 is a perspective view showing an embodiment of a rolling element.

FIG. 4 is a perspective view showing another form of the rolling element.

FIG. 5 is a perspective view of a rolling element having one plane in another embodiment of the rolling element.

FIG. 6 is a diagram showing a ratio (b / D) between a diameter D of a rolling element and a range b that defines roughness.

FIG. 7 is an enlarged cross-sectional view of a main part in the first embodiment.

FIG. 8 is a cross-sectional view showing a method for polishing a rolling element.

FIG. 9 is a perspective view showing an embodiment of a cage.

FIG. 10 is a perspective view showing an embodiment of a separator.

FIG. 11 is a sectional view showing a part of the rolling bearing of the second embodiment.

FIG. 12 is a cross-sectional view of a main part showing an example of a specific example of the present embodiment.

FIG. 13 is a cross-sectional view of a main part showing another example.

FIG. 14 is a cross-sectional view of a main part showing another example.

FIG. 15 is a main-portion cross-sectional view showing another example.

FIG. 16 is a sectional view showing a part of the rolling bearing of the third embodiment.

FIG. 17 is a main-portion cross-sectional view showing an example of a specific example of this embodiment.

FIG. 18 is a main-portion cross-sectional view showing another example.

FIG. 19 is a main-portion cross-sectional view showing another example.

FIG. 20 is a vertical cross-sectional view of a cross roller bearing according to an example of a conventional technique.

FIG. 21 is a vertical cross-sectional view of a four-point contact ball bearing, which is an example of a conventional technique.

FIG. 22 is a longitudinal sectional view of a three-point contact ball bearing, which is an example of a conventional technique.

[Explanation of symbols]

1: Bearing ring (outer ring) 1a and 1b: Raceway surface 2: Race ring (inner ring) 2a ・ 2b: Raceway surface 5: rolling element 5a: Rolling surface (outer diameter) 5b: plane D: Diameter of rolling element b: Range that defines roughness

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yukio Sato             1-5-50 Shinmei Kugenuma, Fujisawa City, Kanagawa Prefecture             Honseiko Co., Ltd. F term (reference) 3J101 AA15 AA25 AA26 AA32 AA33                       AA54 AA62 BA06 BA50 BA53                       BA54 BA55 BA64 EA01 EA31                       EA36 FA31 FA41 GA31 GA32                       GA34 GA41 GA51 GA53 GA55

Claims (3)

[Claims] 1. A plurality of rolling elements are incorporated between a pair of races, each race having a raceway groove formed of a raceway having a diameter larger than the radius of the rolling body, and at least one race is Each rolling element is composed of two raceways, and each rolling element has an outer diameter serving as a rolling contact surface that also has a curvature in the axial direction and has at least one flat surface. In addition, the outer diameters of the rolling elements are always in contact with each other at the raceway surface of one raceway ring and the raceway surface of the other raceway wheel, one point each, for a total of two points. The rolling bearing is characterized in that a predetermined roughness is provided only in the vicinity of the contact portion with the raceway surface of the bearing ring. 2. A plurality of rolling elements are incorporated between a pair of races, each race has a raceway groove formed of a raceway having a diameter larger than the radius of the rolling body, and at least one race is Each rolling element is composed of two raceways, and each rolling element has an outer diameter serving as a rolling contact surface that also has a curvature in the axial direction and has at least one flat surface. In addition, the outer diameters of the rolling elements are always in contact with each other on the raceway surface of one raceway ring and the raceway surface of the other raceway ring at one point each, for a total of two points. A rolling bearing comprising a body and having a smooth arc shape continuous from a rolling surface to a flat surface, and an apex of the arc being a contact point with a raceway surface. 3. A plurality of rolling elements are incorporated between a pair of races, each race having a raceway groove formed of a raceway having a diameter larger than the radius of the rolling body, and at least one race is Each rolling element is composed of two raceways, and each rolling element has an outer diameter serving as a rolling contact surface that also has a curvature in the axial direction and has at least one flat surface. At the same time, the outer diameter of each rolling element is always in contact with the raceway surface of one raceway ring and the raceway surface of the other raceway wheel, one point each, for a total of two points. A rolling bearing characterized in that the connecting portion of the flat surface has a smooth arc shape with at least one curvature.