TW202238010A - Cross roller bearing - Google Patents

Abstract

The present invention has an outer ring (2) comprising a V-groove-shaped outer ring raceway surface (5) formed on an inner diameter side, an inner ring (3) comprising a V-groove-shaped inner ring raceway surface (6) formed on an outer diameter side, the inner ring raceway surface (6) facing the outer ring raceway surface (5), and a plurality of rollers (4) disposed between the outer ring raceway surface (5) and the inner ring raceway surface (6) over the entire circumference in the circumferential direction such that the inclination angle alternately changes. A straight section (9, 10) of which the circumferential cross section is in the form of a straight line, a first crowning (11) having a predetermined drop amount, and a second crowning (12) connecting the straight section (9, 10) and the first crowning (11) and having a predetermined radius R of curvature are formed on at least either the outer ring raceway surface (5) or the inner ring raceway surface (6).

Description

Crossed Roller Bearings

The present invention relates to a crossed roller bearing in which rollers are arranged between an outer ring and an inner ring in different directions of alternating inclination in the circumferential direction.

Crossed roller bearings used in reducers of industrial robots, etc. seek stable characteristics such as high positioning accuracy, repeatability accuracy, and high moment rigidity.

For example, a cross roller bearing disclosed in Patent Document 1 below has an outer ring and an inner ring formed in a ring-shaped integral structure. On the inner peripheral surface of the outer ring, form a V-shaped track surface that opens inward along the circumferential direction, and on the outer peripheral surface of the inner ring, form a V-shaped track surface that opens outward in a manner that faces the track surface of the outer ring along the circumferential direction the track surface. For example, as shown in FIGS. 9( a ) and ( b ), the outer ring 20 is formed with a roller insertion hole 22 for inserting a roller 25 (refer to FIG. 10 ) from its outer peripheral surface to the outer wheel raceway surface 21 . Further, a plurality of rollers 25 are interposed between the raceway surfaces 21, 24 of the inner and outer rings 20, 23 from the roller insertion hole 22 so that the rotation axes of adjacent ones are alternately perpendicular to each other (see FIG. 10 ). Thereafter, a substantially columnar cap (plug) formed to close the roller insertion hole 22 is provided on the roller insertion hole 22 .

Generally speaking, the raceway surface of the crossed roller bearing is not raised, and is only composed of a straight line inclined at 45° relative to the axial direction of the bearing. And, the rolling surface of the roller is in contact with the raceway surface and rolls (see paragraph 0012 of Patent Document 1 below, FIG. 1 , etc.). [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Patent No. 3739056

[Problem to be solved by the invention]

As in the case of the crossed roller bearing of Patent Document 1, as shown in FIG. 10 , the V-shaped outer raceway surface 21 and inner raceway surface 24 formed on the outer raceway 20 and inner raceway 23 and the rollers are respectively Ideally, the rolling surface of the roller 25 is in contact with the entirety of the roller 25 in the axial direction.

However, when the load moment is loaded, as shown in the distribution of the contact surface pressure in FIG. part) and the bottom side of the groove (the edge part of the notch 26 formed at the bottom of the groove bottom of the inner and outer raceways 21, 24) (the part marked E in FIG. 10 ) produces edge stress, and generates The risk of wear, peeling, etc.

Also, in the form in which the plug is provided in the roller insertion hole 22 formed in the outer ring 20, the roller 25 is in contact with the edge portion of the notch 26 extended in the circumferential direction across the roller insertion hole 22 (FIG. 9(b) The portion with a dotted circle in the center), it is easy to start from the edge portion to cause peeling on the outer wheel raceway surface 21 or to produce a gap in the roller 25. Although it is also contemplated that the rollers 25 may be raised to achieve uniform distribution of the contact surface pressure, it is necessary to manage the assembly direction of the rollers 25, which causes an increase in manufacturing cost. In addition, it is considered that the stable operation of the bearing may be reduced due to variations in processing accuracy of the dimensions of the protrusions formed on each roller.

Therefore, the problem of the present invention is to make the distribution of the contact surface pressure acting on the raceway surface uniform and to prolong the life of the bearing under the load of moment load. [Technical means to solve the problem]

In order to solve the above problems, the present invention constitutes a crossed roller bearing, which has: The outer wheel has a V-groove outer wheel track surface formed on the inner diameter side; The inner wheel has a V-groove inner wheel track surface facing the outer wheel track surface on the outer diameter side; A plurality of rollers are arranged between the above-mentioned outer wheel track surface and the above-mentioned inner wheel track surface in such a way that the inclination angles alternately change, and are arranged throughout the entire circumference; At least one of the outer raceway surface or the inner raceway surface is formed with a linear portion with a linear cross-section in the circumferential direction, a first raised portion with a specific lowering amount, and the straight portion and the first raised portion being smooth The connected second raised portion has a specific radius of curvature.

In this way, the edge stress caused by the local excessive contact between the raceway surface and the roller is reduced. Therefore, the distribution of the contact surface pressure acting on the raceway surface can be made uniform when the moment load is applied, and the life of the bearing can be extended.

In the above configuration, the first raised portion having a shape different from each other may be formed on each of the outer raceway surface and the inner raceway surface.

In this way, the distribution of the contact surface pressure generated in the outer ring and the inner ring can be uniformed, and the edge stress can be appropriately reduced.

In each of the above configurations, the above-mentioned first raised portion may be formed on at least one of the groove bottom side and the groove shoulder side of each of the above-mentioned raceway surfaces.

In this way, even if edge stress occurs on either the bottom side of the groove or the shoulder side of the groove according to the load condition, the edge stress can be appropriately reduced.

In the above configuration, the first raised portion having different shapes from each other may be formed on each of the groove bottom side and the groove shoulder side.

In this way, in response to the distribution of the contact surface pressure when the moment load is applied, an appropriate amount of reduction can be set on the groove bottom side and the groove shoulder side, and the distribution of the contact surface pressure acting on the track surface can be made uniform.

In each of the above-mentioned configurations, it is preferable to configure the above-mentioned radius of curvature within the range of 0.1 mm to 3.0 mm.

In this way, the contact surface pressure between the raceway surface and the roller can be uniformed, the life of the bearing can be prolonged, and high moment rigidity can be ensured.

In each of the above configurations, it is preferable that in the circumferential cross-section, an extension line extending from the straight line portion to the side of the first raised portion and a straight line connecting both ends of the first raised portion extend to the straight line. The distance from the intersection point of the extension lines on the side of the portion to the second raised portion is within the range of 0.1 μm to 3.0 μm.

In this way, the contact surface pressure between the raceway surface and the roller can be uniformed, the life of the bearing can be prolonged, and high moment rigidity can be ensured.

In each of the above configurations, the outer ring and the inner ring may have an integral structure that is not divided in the axial direction, and rollers for inserting the rollers from the outer peripheral surface of the outer ring to the raceway surface of the outer ring may be formed on the outer ring. The insertion hole is provided in the above-mentioned roller insertion hole with a plug that closes the roller insertion hole and constitutes a part of the raceway surface of the outer wheel.

In this way, it is possible to prevent the edge portion of the notch extending in the circumferential direction across the roller insertion hole from contacting the roller and starting from the edge portion, from peeling off the raceway surface of the outer wheel or from creating a chip in the roller.

In each of the above-mentioned configurations, it may be configured as a full-roller type in which no cage or spacer for maintaining a specific interval is provided between the above-mentioned rollers adjacent in the circumferential direction.

Thus, more rollers can be provided between the inner and outer rings compared to the case where a cage or the like is provided, and the rigidity of the crossed roller bearing can be improved and the life of the crossed roller bearing can be further increased.

In each of the above configurations, the first raised portion may be formed only on each of the raceway surfaces, and the rollers may not be raised.

In this way, due to the variation in processing accuracy of the protrusion size formed on each roller, it is possible to prevent the stable operation of the bearing from deteriorating, and since it is not necessary to manage the assembly direction of the rollers, it is possible to suppress the manufacturing cost.

In each of the above configurations, the first raised portion may be constituted only by a portion having a linear section in the circumferential direction.

In this way, compared with the case where the circumferential cross section of the first raised portion is curved, processing can be facilitated and manufacturing cost can be suppressed. [Effect of Invention]

In the present invention, since the second raised portion with a specific radius of curvature that smoothly connects the straight line portion and the first raised portion is formed in the crossed roller bearing, it is possible to compress the contact surface of the raceway surface when the moment load is applied. Uniform distribution and long service life of bearings.

An embodiment (first example) of the crossed roller bearing 1 of the present invention will be described using the drawings. In the following description, the direction parallel to the rotation axis of the Crossed Roller Bearing 1 is referred to as the axial direction, and the direction perpendicular to the rotation axis is referred to as the radial direction. The direction is called circumferential. As shown in Figures 1 and 2, the crossed roller bearing 1 comprises an outer ring 2, an inner ring 3 disposed coaxially with the outer ring 2 on the inner diameter side of the outer ring 2, and an inner ring 3 interposed between the outer ring 2 and the inner ring 3. A plurality of rollers 4 are main components. These components are all made of steel.

On the inner diameter side of the outer ring 2, a substantially orthogonal V-groove outer wheel raceway surface 5 is formed, and on the outer diameter side of the inner ring 3, a V-groove inner raceway facing and substantially orthogonal to the outer raceway surface 5 is formed. Orbital surface 6. Hereinafter, the deeper side of the groove shoulder of each raceway surface 5, 6 toward the middle position in the radial direction of the groove bottom is called the groove bottom side, and the shallower side is called the groove shoulder side. On the groove bottom of each raceway surface 5, 6, a continuous notch 7 is formed over the entire circumference in the circumferential direction. Also, in the outer ring 2, as shown in Fig. 9 (a) (b), a roller insertion hole 8 (refer to Fig. 5 ) for inserting the roller 4 from its outer peripheral surface to the outer wheel raceway surface 5 is formed.

As shown in Fig. 2 and Fig. 3, at the radial middle positions of the inner and outer raceway surfaces 5, 6, there are formed linear portions 9, 10 inclined at 45 degrees relative to the axial direction. On the groove bottom side and the groove shoulder side of the straight parts 9, 10, the first raised portion 11 with a specific lowering amount (the size of the gap between the rolling surface of the roller 4 and the inner and outer wheel track surfaces 5, 6) is formed respectively. . The circumferential cross section of the first raised portion 11 is composed of only linear portions, and the lowering amount becomes larger toward the groove bottom side or the inner peripheral surface side of the outer ring 2 or the outer peripheral surface side of the inner ring 3 .

Between the straight parts 9, 10 and the first raised part 11 formed on the bottom side of the groove and the shoulder side of the groove, there is formed a curve with a specific radius of curvature R that smoothly connects the straight parts 9, 10 and the first raised part 11. the second raised portion 12 . The term "smooth" here means that the slope of the surface normal of the second raised portion 12 changes continuously from the connecting portion with the straight line portions 9 and 10 to the connecting portion with the first raised portion 11, as if there is no pin angle in the middle. There are angular parts or discontinuous parts. The processing of the second raised portion 12 is carried out by all methods of mechanical control such as grinding, drum, drum, blasting, ultra-finishing, or manual operations such as manual grinding.

In addition, in Fig. 2 (the same is true for Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 and Fig. 8 showing the cross-sectional view of the main part of the crossed roller bearing 1), the inner and outer rings are formed for easy visual observation. The first raised portion 11 and the second raised portion 12 of the track surface 5,6, and the inclination angle of the first raised portion 11 is exaggeratedly drawn, the actual inclination angle (for example, about 2 degrees) is very small, and the radius of curvature R (for example, 0.6 mm) is very large, and the angle change from the straight part 9, 10 to the first raised part 11 is very gentle, so when the moment load is applied, the rolling surface of the inner and outer wheel track surfaces 5, 6 and the roller 4 can spread throughout the roller The axis of 4 is in contact with the whole.

Based on the bearing life and moment rigidity of the shape of the inner and outer wheel raceway surfaces 5, 6 formed by the straight parts 9, 10, the first raised part 11 and the second raised part 12, as described later, it is the same as that shown in Fig. 4 (1 ) the radius of curvature R of the second raised portion 12, and (2) the extension line extending the straight line portions 9 and 10 on the side of the first raised portion 11 and the straight line connecting the two ends of the first raised portion 11 in the circumferential section The size of the distance L from the intersection point of the extension lines extended on the side of the straight line parts 9 and 10 to the second raised part 12 is quite related. In this first example, the first raised portion 11 and the second raised portion 12 formed on the groove bottom side and the groove shoulder side of the outer wheel raceway surface 5 and the groove bottom side and the groove shoulder side of the inner wheel raceway surface 6 respectively same shape. In addition, the width of the first raised portion 11 and the second raised portion 12 along the depth direction of the V-grooves on the inner and outer raceway surfaces 5, 6 can be appropriately determined, but according to the point of pressure management, it is preferable to make the two raised portions 11, 12 The total width of 12 is set to be 50% or less of the widths of straight portions 9 and 10 .

The rollers 4 are arranged over the entire circumference in such a manner that the inclination angles of the adjacent rollers 4 in the circumferential direction alternately vary by 90 degrees between the outer raceway surface 5 and the inner raceway surface 6 . The diameter of the roller 4 is slightly longer than the length in the direction of its axis of rotation. Therefore, the end of the roller 4 in the direction of the rotation axis does not roll with the rolling surface of the roller 4. The surface of the inner and outer wheel raceway surfaces 5, 6 constituting one side of the V groove and the surface on the other side that is substantially orthogonal Contact allows the roller to roll smoothly.

The rolling surface of the roller 4 is a cylindrical surface with a constant outer diameter throughout the entire axial direction, and is not raised. Therefore, when the roller 4 is assembled between the inner and outer raceway surfaces 5, 6, it is not necessary to manage the direction of the assembly, and the assembly operation can be smoothly performed. In this embodiment, there is no cage or spacer between the adjacent rollers 4 in the circumferential direction. It can also be configured to hold the rollers 4 with the cage or to The spacer is arranged between the adjacent rollers 4 to secure a gap of a specific size between the rollers 4 .

If the assembly of the roller 4 is completed, then as shown in Figure 5, a plug 13 that plugs the roller insertion hole 8 and constitutes a part of the outer wheel track surface 5 is provided in the roller insertion hole 8 formed in the outer wheel 2, and the plug 13 for insertion With the pin 14 that prevents the plug 13 from falling off, the assembly of the cross roller bearing 1 is completed. In this plug 13, in a manner continuous with the notch 7 formed on the outer wheel raceway surface 5, the straight portion 9, the first raised portion 11, and the second raised portion 12 in the circumferential direction, they are respectively formed with the same shape in the circumferential cross section. The notch 7 , the straight portion 9 , the first raised portion 11 , and the second raised portion 12 .

In addition, in the first example, bulges are formed on both the groove bottom side and the groove shoulder side of the inner and outer raceway surfaces 5 and 6, but the magnitude of the stress varies due to the load conditions, so sometimes it can also be configured to be only on the inner and outer raceways. One side of the faces 5, 6 or only one side of the groove bottom side or the groove shoulder side is formed with a bulge. In addition, it is sometimes also possible to form protrusions of different shapes between the outer raceway surface 5 and the inner raceway surface 6 or between the bottom side of the groove and the shoulder side of the groove.

Fig. 6 shows an example of the distribution of the contact surface pressure acting on the raceway surfaces 5, 6 of the inner and outer rings when a moment load of a specific magnitude is applied to the assembled crossed roller bearing 1. It can be confirmed that by forming the straight portions 9, 10, the first raised portion 11, and the second raised portion 12 on the inner and outer ring raceway surfaces 5, 6, the groove shoulder side of the V groove (the edge portion on the inner peripheral surface side of the outer ring 2 and the The edge stress near the edge of the outer peripheral surface of the inner ring 3) and the bottom of the groove (the edge of the notch 7 formed at the bottom of the inner and outer ring raceways 5, 6) is significantly larger than before (see Figure 10). reduce.

Also, as mentioned above, by using the first protruding portion 11 and the second protruding portion 12 to form a protuberance, as shown in FIG. In the bearing 1, it is also possible to prevent the edge portion of the notch 7 from contacting the roller 4, and starting from the edge portion, peeling off on the outer raceway surface 5 or notch on the roller 4 can be prevented.

The reduction of the edge stress can also be realized by using a logarithmic bulge for the first bulge 11 to smoothly connect the linear portions 9, 10 of the inner and outer raceway surfaces 5, 6 with the first bulge 11 with a tangent. However, because logarithmic ridges are difficult to process, the cost tends to be high, and the above configuration of connecting the linear portions 9, 10 and the first ridge 11 with the second ridge 12 that can be processed at a lower cost is more advantageous.

As described above, the difference in the bearing life between the straight portions 9 and 10 and the first raised portion 11 when the second raised portion 12 is formed and when it is not formed was verified. Table 1 shows its verification results. Sample No. 1 shown in Table 1 is the result when the second raised portion 12 is not formed (comparative example), and sample No. 2 is the result when the second raised portion 12 is formed (example).

In the No.2 sample (example), the radius of curvature R (R2) of the second raised portion 12 is 0.6 mm, and the focal point of the extension lines of the straight lines 9, 10 and the first raised portion 11 reaches the second raised portion The distance L between the portions 12 is 0.5 μm. In the No.1 sample (comparative example), the second raised portion 12 is not formed, but the intersection of the straight line portions 9, 10 and the first raised portion 11 is slightly rounded (radius of curvature R(R1)=0.05 mm) There is a small distance L of less than 1 μm between the intersection point of the extension lines of the linear portions 9 and 10 and the first raised portion 11 and the above-mentioned circle.

After carrying out the bearing durability test on the two samples, it can be confirmed that compared with the comparative example without the second raised portion 12, the bearing life ratio of the embodiment with the second raised portion 12 is 2.8, and the life is greatly improved. The reason for this is considered to be that by forming the second raised portion 12, as shown in FIG. 6, the edge stress accompanying the contact between the inner and outer raceway surfaces 5, 6 and the rollers 4 is reduced.

[Table 1] Sample No. Formation of the second bulge Radius of curvature R [mm] Distance L [μm] Bearing life ratio 1 (comparative example) none 0.05(R1) Less than 0.1 1 2 (Example) have 0.6(R2) 0.5 2.8

Next, the quality of bearing life and moment rigidity when changing the radius of curvature R of the second raised portion 12 was evaluated. Table 2 shows the results of this evaluation. The mark "⊚" in Table 2 (and the same in Table 3) means extremely good, "〇" means excellent, and "×" means poor (possibility of practical problems). In addition, the symbol "-" means that as the radius of curvature R becomes larger, the straight line portions 9 and 10 become shorter, and accordingly, the advantages and disadvantages gradually change in the order of "◎ → ○ → ×". Also, if the radius of curvature R is further increased, the first raised portion 11 may disappear, and the shape may be formed only by the notch 7, the second raised portion 12, and the straight portions 9, 10. In this regard, in Table 3 described later, the same applies when the distance L becomes larger than 3.0 μm.

According to the evaluation results, it is found that the radius of curvature R is in the range of 0.1 mm to 3.0 mm, and good bearing life and moment rigidity can coexist. In particular, when the radius of curvature R is in the range of 0.6 mm to 3.0 mm, the bearing life is particularly good. On the other hand, it was found that when the radius of curvature R is less than 0.05 mm, the practical bearing life may not be ensured, and that when the radius of curvature R exceeds 3.0 mm, both the bearing life and the moment rigidity decrease.

[Table 2] Radius of curvature R [mm] 0.05 0.1 0.2 0.6 1.0 2.0 3.0 more than 3.0 Bearing life x 〇 〇 ◎ ◎ ◎ ◎ - Moment stiffness ◎ 〇 〇 〇 〇 〇 〇 x

Furthermore, when the distance L from the intersection point of the extension lines of the linear portions 9, 10 and the first raised portion 11 to the second raised portion 12 was changed, the bearing life and moment rigidity were evaluated. Table 3 shows the results of this evaluation.

According to the evaluation result, it is known that a good bearing life and moment rigidity can coexist when the distance L is in the range of 0.1 μm to 3.0 μm. In particular, when the distance L is in the range of 0.2 μm to 3.0 μm, the bearing life is particularly good. On the other hand, it was found that when the distance L is less than 0.1 μm, there is a possibility that the practical bearing life cannot be ensured, and that when the distance L exceeds 3.0 μm, both the bearing life and the moment rigidity decrease.

[table 3] Distance L [μm] Less than 0.1 0.1 0.2 0.5 1.0 2.0 3.0 more than 3.0 Bearing life x 〇 ◎ ◎ ◎ ◎ ◎ - Moment stiffness ◎ 〇 〇 〇 〇 〇 〇 x

In addition, the evaluation results shown in Table 2 and Table 3 are based on crossed roller bearings 1 (for example, with an outer diameter of about 50 to 240 mm) used in reduction gears for industrial robots. If the bearing size deviates from this range, the There is a possibility that the values of the radius of curvature R and the distance L that exert good bearing life and moment rigidity may also vary.

Fig. 7 shows another embodiment (second example) of the crossed roller bearing 1 of the present invention. The crossed roller bearing 1 of the second example has the same basic structure as that of the first example, but the shape of the bulge is different on the groove bottom side and the groove shoulder side of the inner and outer raceway surfaces 5 and 6 . That is, in the second example, the circumferential section of the first raised portion 11 on the groove shoulder side of the inner and outer ring track surfaces 5, 6 is formed by a curved position, and the more toward the inner peripheral surface side of the outer ring 2 or the inner ring 3 On the outer peripheral surface side, the lowering amount becomes larger.

In this second example, the second raised portion 12 is formed between the linear portions 9, 10 and the first raised portion 11 formed of the curved portion, and the edge stress can be significantly reduced as compared with the first example as in the first example. In addition, in the second example, the circumferential cross-sectional shape of the first protruding portion 11 is set as a straight line on the groove bottom side and a curved shape on the groove shoulder side. The shape of the first protruding portion 11 can be appropriately changed such as a curved shape, a linear shape on the groove shoulder side, or a curved shape on both the groove bottom side and the groove shoulder side, etc. In addition, it may be possible to make it into a curved shape in which the curvature changes halfway. Also, there is a case where the bulge is formed only on one side of the inner and outer raceway surfaces 5, 6.

In addition, when the first raised portion 11 is curved, the extension line extending the straight portions 9 and 10 on the side of the first raised portion 11 and the straight line connecting the two ends of the first raised portion 11 are placed on the side of the straight parts 9 and 10. The distance between the point of intersection of the extended extension lines and the point where the bisector of the angle formed by the two extension lines intersects with the second raised portion 12 is set to the above-mentioned distance L.

Fig. 8 shows still another embodiment (third example) of the crossed roller bearing 1 of the present invention. The crossed roller bearing 1 of the third example also has the same basic structure as that of the first example, but the shape of the protrusions on the groove bottom side and the groove shoulder side of the inner and outer raceway surfaces 5, 6 are different. That is, in the third example, the width of the first raised portion 11 along the depth direction of the V-groove becomes wider on the groove shoulder side than on the groove bottom side, and becomes wider toward the groove bottom side or the inner peripheral surface side of the outer ring 2 Or on the outer peripheral surface side of the inner ring 3, the lowering amount becomes larger.

In the third example, the second raised portion 12 is formed between the linear portions 9, 10 and the first raised portion 11, which can greatly reduce the edge stress as in the first example. In addition, in the third example, the width of the first raised portion 11 is made wider on the groove shoulder side than the groove bottom side, but on the contrary, it may be wider on the groove bottom side than the groove shoulder side. Also, there is a case where the bulge is formed only on one side of the inner and outer raceway surfaces 5, 6.

It should be understood that the embodiments disclosed this time are illustrative and not restrictive at all points. The scope of the present invention is not the above-mentioned description, but intends to include all changes within the meaning and range equal to the claims and the claims.

1: Cross roller bearing 2: outer wheel 3: inner wheel 4: Roller 5: Outer wheel track surface 6: Inner wheel track surface 7: notch 8: Roller insertion hole 9: Straight line 10: Straight line 11: The first uplift 12: Second uplift 13: Embolization 14: pin 20: outer wheel 21: Outer wheel track surface 22: Roller insertion hole 23: inner and outer wheels 24: Orbital surface 25: Roller 26: notch E: symbol L: distance R: radius of curvature R1: radius of curvature R2: radius of curvature

Fig. 1 is a front view with a part of the crossed roller bearing of the present invention cut away. Fig. 2 is a sectional view along line II-II in Fig. 1 (first example). Fig. 3 is a cross-sectional view of the main part of Fig. 2 . Fig. 4 is a cross-sectional view of further main parts of Fig. 3 . Fig. 5 is a sectional view showing the steps of setting the plug on the outer ring. Fig. 6 is a cross-sectional view showing an example of the distribution of the contact surface pressure acting on the raceway surface. Fig. 7 is a sectional view of the main part of the crossed roller bearing (second example). Fig. 8 is a sectional view of the main part of the crossed roller bearing (third example). Figure 9 (a) is a sectional view of the previous outer wheel, and (b) is the main part of (a). Fig. 10 is a sectional view showing an example of the distribution of contact surface pressure acting on the raceway surface of a conventional crossed roller bearing.

1: Cross roller bearing

2: outer wheel

3: inner wheel

4: Roller

7: notch

9: Straight line

10: Straight line

11: The first uplift

12: Second uplift

Claims (10)

A crossed roller bearing having: The outer wheel (2), which is formed with a V-groove outer wheel track surface (5) on the inner diameter side; The inner wheel (3), which is formed with a V-groove inner wheel track surface (6) opposite to the outer wheel track surface (5) on the outer diameter side; A plurality of rollers (4) are arranged between the above-mentioned outer wheel track surface (5) and the above-mentioned inner wheel track surface (6), in such a way that the inclination angles alternately change, and are arranged throughout the entire circumference; At least one of the above-mentioned outer wheel track surface (5) or the above-mentioned inner wheel track surface (6) is formed with a straight line portion (9, 10) having a linear cross section in the circumferential direction, and a first raised portion (11) with a specific lowering amount. ), and a second raised portion (12) with a specific radius of curvature (R) that smoothly connects the above-mentioned linear portion (9, 10) and the above-mentioned first raised portion (11). The crossed roller bearing according to claim 1, wherein the first protrusions (11) having different shapes are formed on each of the outer raceway surface (5) and the inner raceway surface (6). The crossed roller bearing according to claim 1 or 2, wherein the above-mentioned first raised portion (11) is formed on at least one of the groove bottom side and the groove shoulder side of each of the above-mentioned raceways (5, 6). The crossed roller bearing according to claim 3, wherein the first protrusions (11) having different shapes are formed on each of the groove bottom side and the groove shoulder side. The crossed roller bearing according to any one of claims 1 to 4, wherein the radius of curvature (R) is in the range of 0.1 mm to 3.0 mm. The crossed roller bearing according to any one of claims 1 to 5, wherein in the circumferential section, an extension line extending from the straight line portion (9, 10) to the first raised portion (11) side, and The distance (L) from the intersection point of the straight line connecting the two ends of the first raised portion (11) to the side of the straight line portion (9, 10) to the second raised portion (12) is 0.1 μm or more Within the range below 3.0 μm. The crossed roller bearing according to any one of claims 1 to 6, wherein the above-mentioned outer ring (2) and the above-mentioned inner ring (3) have an integral structure that is not divided in the axial direction, and the above-mentioned outer ring (2) is formed from The roller insertion hole (8) for the insertion of the above-mentioned roller (4) from the outer peripheral surface to the above-mentioned outer wheel track surface (5) is provided in the above-mentioned roller insertion hole (8) to plug the roller insertion hole (8 ) and a plug (13) that forms part of the above-mentioned outer wheel track surface (5). The crossed roller bearing according to any one of claims 1 to 7, wherein it is a full-roller type in which no cage or spacer for maintaining a specific interval is provided between the above-mentioned rollers (4) adjacent in the circumferential direction . The crossed roller bearing according to any one of claims 1 to 8, wherein the first raised portion (11) is formed only on each of the raceway surfaces (5, 6), and no raised processing is performed on the roller (4) . The crossed roller bearing according to any one of claims 1 to 9, wherein the above-mentioned first raised portion (11) is composed only of a portion whose circumferential section is linear.

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