JPH0712119A - Cylindrical roller bearing - Google Patents

Abstract

(57) [Abstract] [Purpose] Even when the cylindrical roller 5 is skewed, abrasion of the end surface 12 of the cylindrical roller 5 and the inner side surfaces 11a, 11a of the collars 7, 7 is suppressed. [Structure] Inner side surfaces 11a, 11a of the collars 7, 7 are inclined by an angle θ defined within a range of 5 minutes to 3 degrees. When the cylindrical roller 5 is skewed, the cylindrical roller 5
The contact points between the and the collars 7, 7 are located on the inner side surfaces 11a, 11a. That is, the contact point is not located at the edge of each of the collars 7, 7 as in the conventional case.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The cylindrical roller bearing according to the present invention is
The present invention relates to improvement of cylindrical roller bearings that rotate at high speed, such as gas turbines and jet engines.

[0002]

2. Description of the Related Art Cylindrical roller bearings as shown in FIG. 1 are widely used to support various rotating parts such as a rotating shaft of a gas turbine. This cylindrical roller bearing is rotatably provided between an inner ring 2 having an inner ring raceway 1 on an outer peripheral surface, an outer ring 4 having an outer ring raceway 3 on an inner peripheral surface, and the inner ring raceway 1 and the outer ring raceway 3 described above. A plurality of cylindrical rollers 5 and a cage 6 rotatably provided between the inner ring raceway 1 and the outer ring raceway 3 while holding the plurality of cylindrical rollers 5 are provided.

A pair of collars 7, 7 is formed at both ends of the inner ring raceway 1. The interval between the collars 7, 7 is slightly larger than the length dimension of the cylindrical roller 5 in the axial direction (the left-right direction in FIG. 1). Therefore, the cylindrical rollers 5 are sandwiched by the pair of collars 7, 7 from both sides in the axial direction, and are prevented from being displaced in the axial direction. Each of the cylindrical rollers 5 is provided with chamfered portions 10 and 10 between the rolling surface 8 and both axial end surfaces 9 and 9.

When the cylindrical roller bearing constructed as described above is used, for example, the inner ring 2 is externally fitted and fixed to the intermediate portion of the rotary shaft, and the outer ring 4 is internally fitted and fixed to the housing. When the rotary shaft rotates, the plurality of cylindrical rollers 5 roll,
The inner ring 2 is allowed to rotate inside the outer ring 4.

By the way, when the cylindrical roller bearing is used, each cylindrical roller 5 rotates while the central axes of the cylindrical rollers 5 and the central axes of the inner ring 2 and the outer ring 4 are not parallel to each other, so-called skew. Inevitably occurs. When such a skew occurs, the outer peripheral edge portions of both end surfaces of the cylindrical rollers 5 and the flanges 7, 7 are in sliding contact with each other. Therefore, unless some measures are taken, under bad conditions such as poor lubrication. In some cases, both ends of the cylindrical rollers 5 and the collars 7, 7 may be significantly worn.

Therefore, in the past, Japanese Patent Laid-Open No. 56-17415
As disclosed in Japanese Patent Publication No. JP-A No. 2003-242242, the inclination angle of the inner surface of the collar is changed in the middle, or as described in US Pat. No. 4,027,930, the inner surface of the collar is curved with a predetermined radius of curvature. There is known a technique of forming a lubricating oil film between the ends of the cylindrical roller and the flange by a wedge effect when the cylindrical roller is skewed by forming the convex surface.

[0007]

However, the process of changing the inclination angle of the inner surface of the collar or making the inner surface of the collar convex is a small cylindrical roller bearing, and therefore the height of the collar is not large. It becomes difficult when the dimensions (dimensions in the diameter direction) are small.

Further, in any case, since the inner surface of the collar is convex, the surface pressure of the contact portion becomes large, and in the situation where the wedge effect of the lubricating oil cannot be expected under poor lubrication, the contact portion There is a risk that metal contact will occur and wear will progress. The cylindrical roller bearing of the present invention has been invented to prevent such wear of the collar and the cylindrical roller bearing.

[0009]

A cylindrical roller bearing according to the present invention includes an inner ring having an inner ring raceway on an outer peripheral surface, an outer ring having an outer ring raceway on an inner peripheral surface, as in the conventional cylindrical roller bearing described above. A plurality of cylindrical rollers rotatably provided between the inner ring raceway and the outer ring raceway, and slightly larger than the length dimension of each cylindrical roller on both sides of one of the inner ring raceway and the outer ring raceway. It is provided with a pair of collars provided at intervals.

Particularly, in the cylindrical roller bearing of the present invention,
It is characterized by satisfying the following conditions (a) to (d). (A) The inner side surfaces of the pair of flanges are inclined at the same angle from the base end portion to the front end portion. (B) The inclination angle of the inner side surface of each of the collars is in the range of 5 minutes to 3 degrees with respect to the planes perpendicular to the central axes of the inner ring and the outer ring. (C) The inclination direction of each inner side surface should be such that the distance between the inner side surfaces becomes wider as the distance from the raceway surface between the pair of flanges increases. (D) When the central axis of the cylindrical roller is not parallel to the central axes of the inner ring and the outer ring, and the outer peripheral edge portions of both end surfaces of the cylindrical roller come into contact with the flanges, the contact points are different from each other. On the inside
Be located closer to the base end than the front edge of each tsuba.

[0011]

According to the cylindrical roller bearing of the present invention configured as described above, even if the cylindrical rollers are skewed and the outer peripheral edge portions of both end surfaces of the cylindrical rollers are in sliding contact with the inner side surface portion of the flange, this sliding The edge load working on the contact area is small. In addition, the oil film, which is a fluid wedge film, is efficiently formed on the sliding contact portion, and it is difficult for the sliding contact portion to be brought into contact with the metal, which would lead to remarkable wear. As a result, it is possible to prevent wear of the inner surface portion.
Next, these reasons will be described in detail.

First, in order to reduce the edge load,
Even when the cylindrical rollers 5 are skewed, the outer peripheral edge of the end surface of the cylindrical rollers 5 contacts the flat inner surface of the flange 7 instead of the leading edge of the flange 7, so that the cylindrical rollers 5 contact the inner surface of the flange 7. It is desirable to regulate the contact position. For example, as shown in FIGS. 2-3, between the pair of flanges 7, 7 having an inner side surface 11 extending in a direction perpendicular to the central axis of the inner ring 2 and having a height h from the inner ring raceway 1 is h. Then, consider a case where the cylindrical roller 5 having a length dimension of l _r is arranged (conventional shape). When one end surface 12 (right side in FIG. 2) of the cylindrical roller 5 is abutted against the inner side surface of the one flange 7, the other end surface 12 (left side in FIG. 2) of the cylindrical roller and the other flange A gap of Δl is formed between the inner surface of 7 and the inner surface of 7. Setting Δl / l _r = ζ (<< 1), the cylindrical roller 5 is not skewed, and the end surface 12 and the inner surface 11 are
When the contact length between the two surfaces 12 and 11 is 2b when and are in contact with each other, the skew angle ψ of the cylindrical roller 5 is expressed by the following equation (1).

[0013]

[Equation 1]

Since ζ << 1 as described above, the above equation (1) can be approximated by the following equation (2). ψ≈sin ^-1 (△ l / 2b) --- (2)

When designing a cylindrical roller bearing, the diameter D _a of each cylindrical roller 5, the chamfering amount C (FIG. 3) formed on the outer peripheral edges of both ends of each cylindrical roller 5, the length of each cylindrical roller 5 Size l _r , diameter D _{i of the} raceway surface with which each cylindrical roller 5 abuts
Is determined, b in the above equation (2) is a function of only h. Therefore, the equation expressing the skew angle ψ is expressed by the following (3)
It can be expressed by a formula. ψ = f (h, Δl) --- (3) That is, the skew angle ψ is a function of only the height h of the collar 7 and the gap Δl at the position.

When the gap Δl is constant, the skew angle ψ becomes smaller as b becomes larger as the height h of the collar 7 increases from the formula (1) or (2). I understand. However, in this state, the outer peripheral edge portions of both ends of the cylindrical roller 5 and the end edge portions of the collars 7, 7 come into contact with each other, and a large edge load is applied to the contact portions. On the other hand, as shown in FIG. 4, the inner side surfaces 11a, 11a of the pair of collars 7, 7 are inclined, and the distance between the inner side surfaces 11a, 11a is such that the pair of collars 7,
It is made wider as it goes away from the raceway surface sandwiched by 7 (for example, the inner ring raceway 1), and as the height h becomes larger, the gap Δl.
When the angle is increased, the skew angle ψ changes two-dimensionally with respect to the height h of the collar 7 as shown in FIG. Then, at the point where the height of the collar 7 is h ₀ , the skew angle ψ has a minimum value ψ _min .

As is apparent from the above, based on the equation (1), the amount of change in the clearance Δl corresponding to the height h, that is, each inner surface 11a, is such that H ₀ <h ₀ <H _1. , 11a
If the inclination angle and heights H ₀ and H ₁ of the cylindrical rollers 5 are skewed, even if the cylindrical rollers 5 are skewed, the outer peripheral edge portion of the end surface of the cylindrical rollers 5 is not the tip edges of the collars 7, 7 but the flat inner surface 11
By contacting a and 11a, the edge load can be reduced.

In the above inequality, H ₀ is a flat inner surface 1
The height position of the base end of 1a is shown. This height position H ₀
For example, as shown in FIG. 4, when there is a relief 13 for grinding at the base end of the collar 7, 7, the relief 13,
13 is the height, and when there is no escape, it is the height dimension of the chamfer between the inner side surfaces 11a, 11a of the collars 7, 7 and the raceway surface sandwiched between the collars 7, 7. H ₁ is the end height position of the flat inner surfaces 11 a, 11 a, and is the height H of the collars 7, 7 minus the dimension of the chamfer formed on the tip edges of the collars 7, 7. To tell.

As described above, in order to regulate the position of the contact portion between the both ends of each cylindrical roller 5 and the inner side surfaces 11a, 11a of the collars 7, 7, the inner side surfaces 11a, 11a are set at an angle θ. It is necessary to incline, but when this inclination angle θ is less than 5 minutes, due to manufacturing error of the end surface of the cylindrical roller 5,
There are cases where it is difficult to obtain the effect. Therefore, the lower limit of the tilt angle is set to 5 minutes.

On the other hand, if the inclination angle θ becomes too large, the skew angle ψ becomes too large, which not only increases the rotational resistance of the cylindrical roller bearing, but also wears the cylindrical rollers 5 and the inner races 2 and the like. Will be the cause. That is, since there is a gap ΔS between the base end portion of each inner side surface 11a and the end surface of the cylindrical roller 5, an increase in the inclination angle θ leads to an increase in the skew angle ψ. Therefore, the upper limit of the inclination angle θ is set to 3 degrees.

Next, with the cylindrical roller 5 skewed,
The reason why the edge load acting on the contact portion between the outer peripheral edge of the end surface of the cylindrical roller 5 and the inner side surface 11a is reduced is as follows.
This will be described with reference to FIGS. Note that FIG. 9 is an explanatory view showing the contact state between the outer peripheral edge portion of the end surface of the cylindrical roller 5 and the inner side surface 11a of the collar 7, and the curve shown by − in FIG. 9 is cut by the − line in FIG. The surface shape of the cylindrical roller 5 in the state is shown. And R ₁ is a cylindrical roller 5 along the line − in FIG.
It represents the radius of curvature of the surface. The curve indicated by-in Fig. 9 represents the surface shape of the cylindrical roller 5 in the state cut along the-line in Fig. 8. Then, R ₂ represents the radius of curvature of the surface of the cylindrical roller 5 along the negative line in FIG.

When the shape of each part corresponding to the sliding contact part is as described above, the contact surface pressure σ acting on the sliding contact part is expressed by the following equation (4).

[Equation 2] In the formula (4), R ₁ ′ is the radius of curvature of the inner side surface 11 a when cut along the − line in FIG. 8, and R ₂ ′ is the inner side surface when cut along the − line in FIG. 8. The radius of curvature of 11a is shown respectively. In the case of the present invention, R ₁ ′ and R ₂ ′ representing the radius of curvature of the flat inner surface 11a are ∞.

Therefore, in the case of the cylindrical roller bearing of the present invention, 1 / R ₁ ′ and 1 / R ₂ ′ in the equation (4) are 0, and the contact surface pressure σ is the following equation (5). Represented by

[Equation 3]

On the other hand, like the conventional cylindrical roller bearing described above, the end surface of the cylindrical roller abuts against the tip edge of the collar 7, or the inclination angle of the inner surface of the collar 7 changes in the middle ( In the case of the invention described in JP-A-56-17415), or the inner side surface is curved (US Pat. No. 4,027,930).
When the inner surface is convex, one or both of 1 / R ₁ ′ and 1 / R ₂ ′ has a positive value having a non-negligible value, and (4) The edge load value expressed by the formula also increases. From this fact, in the case of the cylindrical roller bearing of the present invention, as compared with the conventional structure, the cylindrical roller 5 acts on the contact portion between the outer peripheral edge portion of the cylindrical roller 5 and the inner side surface 11a in a skewed state. You can see that the edge load is reduced.

Next, the reason why the oil film is efficiently formed on the sliding contact portion will be described with reference to FIGS. FIG. 10 shows the flow state of the lubricating oil. When the contact point between the end of the cylindrical roller 5 and the inner side surface 11a of the collar 7 is A, and the inner ring 2 rotates counterclockwise as indicated by arrow a, the lubricating oil has a speed indicated by arrow V in FIG. Flowing in. Rate of the lubricating oil indicated by the arrow V (magnitude and direction) becomes a composite of the speed V ₂ of the speed V ₁ and the rolling elements 5 of the in flange 7 to the contact point A.

FIG. 11 shows the surface shapes of the cylindrical roller 5 and the collar 7 in the state cut along the negative line in FIG. As the cylindrical roller 5 rolls, the lubricating oil is sent toward the contact point A as indicated by an arrow V ′ in FIG.
A strong oil film is formed on the part due to the wedge effect. As a result, abrasion of the sliding contact portion can be effectively prevented.

[0027]

EXAMPLES Next, in order to confirm the effects of the present invention, an experiment conducted by the present inventor will be described. The experiment was performed by operating a cylindrical roller bearing as shown in FIG. 12 with inner ring rotation. The roller bearing has an inner diameter of 42 mm, an outer diameter of 70 mm, and a width of 19
mm, the outer diameter (D _a ) and the length (l _r ) of the cylindrical rollers 5, 5 are all 7 mm. The inner ring 2, the outer ring 4, and the cylindrical rollers 5 and 5 are all made of bearing steel. In addition, concave grooves 15, 15 are formed in a plurality of inner circumferential surfaces of the inner ring 2, and the concave grooves 15, 15 are formed.
The oil passage holes 16 and 16 are provided between the outer peripheral surface of the one collar and the outer peripheral surface of the one collar.

In addition to the above, the dimensions of each part shown in FIGS. 3 and 4 are as follows. C = 0.4 mm D _i = 49 mm H = 2.3 mm H ₀ = 0.5 mm H ₁ = 2.1 mm θ = 35 minutes ΔS = 0.038 mm Therefore b = 2.7 mm h = 1.5 mm Δl = Δl ₁ + Δl ₂ = 0.058 mm.

With this cylindrical roller bearing, under the condition that a radial load of 15 kgf is applied, lubricating oil is supplied through the concave grooves 15 and 15 and the oil passage holes 16 and 52,
It was rotated at 000 rpm for 5 hours. Before and after this rotation test, the surface shapes of the end surface 12 of the cylindrical roller 5 and the inner side surface 11a of the collar portion 7 were measured. The measurement site and the measurement result of the end face 12 are shown in FIG. 13, and the measurement site and the measurement result of the inner surface 11a are shown in FIG.

In the measurement work, the stylus which is brought closer to the surface to be measured from the direction indicated by the arrow α in FIGS. 13 to 14 and abuts against the surface to be measured is moved in the direction indicated by the arrow β. I did it. The measurement results are shown in (B) of each figure.
Although it shows in (C), (B) has shown the measurement result before the said rotation test, (C) has shown the measurement result after a rotation test, respectively. The value of the measurement result of the end surface 12 of the cylindrical roller 5 shown in FIG. 13 is 1000 times in the axial direction of the cylindrical roller 5 (vertical direction in FIG. 13) and 10 in the diametrical direction (also in the horizontal direction). It is shown in doubled scale. Also, FIG.
The value of the measurement result of the inner side surface 11a of the collar 7 described in 1. is 1000 times in the axial direction of the inner ring 2 (vertical direction in FIG. 14),
In the diametrical direction (also in the left-right direction), they are each magnified 20 times.

As is clear from a comparison of (B) and (C) in FIGS. 13 to 14, according to the cylindrical roller bearing of the present invention, the end surface 12 of the cylindrical roller 5 and the inner surface 11a of the collars 7, 7 are worn. Can be suppressed.

In the above description, the collars 7 and 7 are formed on the outer peripheral surfaces of both ends of the inner ring 2, but in the case of a cylindrical roller bearing in which the collars are formed on the inner peripheral surfaces of both ends of the outer ring. Also,
It is obvious that the present invention can be carried out under the same conditions by only reversing the directions of the inner and outer circumferences.

[0033]

Since the cylindrical roller bearing of the present invention is constructed and operates as described above, it is possible to prevent wear and seizure of the end surface of the cylindrical roller and the inner surface of the collar, and to prevent various seizures, and various mechanical devices incorporating the cylindrical roller bearing. The durability and reliability of can be improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an example of a cylindrical roller bearing to which the present invention is applied.

FIG. 2 is a sectional view showing only a cylindrical roller and an inner ring of a conventional cylindrical roller bearing.

FIG. 3 is a perspective view seen from the side of FIG.

FIG. 4 is a sectional view similar to FIG. 2, showing a cylindrical roller bearing of the present invention.

FIG. 5 is a diagram showing the relationship between the skew position and the height position of the contact point between the inner surface of the collar and the outer peripheral edge of the end surface.

FIG. 6 is a front view showing a state where the cylindrical rollers are skewed.

FIG. 7 is a view seen from above in FIG.

FIG. 8 is a view for explaining a contact state between the cylindrical roller and the collar.
Perspective view seen from the side.

FIG. 9 is a partially enlarged perspective view for explaining a contact state between a cylindrical roller and a collar.

FIG. 10 is a view for explaining the feeding state of the lubricating oil.
Similar figure to.

FIG. 11 is an enlarged cross-sectional view taken along the line − in FIG. 10 for explaining the feeding state of lubricating oil.

FIG. 12 is a sectional view of a rolling bearing used in a test for confirming the effect of the present invention.

FIG. 13 is a diagram showing the surface shape measuring position of the end surface of the cylindrical roller incorporated in the cylindrical roller bearing of the present invention and the surface shape before and after the test.

FIG. 14 is a diagram showing a surface shape measurement position on the inner surface of the collar portion of the inner ring incorporated in the cylindrical roller bearing of the present invention, and surface shapes before and after the test.

[Explanation of symbols]

 1 Inner ring raceway 2 Inner ring 3 Outer ring raceway 4 Outer ring 5 Cylindrical roller 6 Retainer 7 Collar 8 Rolling surface 9 Both end faces 10 Chamfered portion 11 and 11a Inner side surface 12 End surface 13 Relief surface 14 Rolling surface 15 Recessed groove 16 Oil hole

Claims (1)

[Claims] 1. An inner ring having an inner ring raceway on an outer peripheral surface, an outer ring having an outer ring raceway on an inner peripheral surface, and a plurality of cylindrical rollers rotatably provided between the inner ring raceway and the outer ring raceway. On both sides of one of the inner ring raceway and the outer ring raceway, a pair of flanges provided at intervals slightly larger than the length dimension of each cylindrical roller is provided, and the following (a) to (d) are provided. ) A cylindrical roller bearing characterized by satisfying the condition (A) The inner side surfaces of the pair of flanges are inclined at the same angle from the base end portion to the front end portion. (B) The inclination angle of the inner side surface of each of the collars is in the range of 5 minutes to 3 degrees with respect to the planes perpendicular to the central axes of the inner ring and the outer ring. (C) The inclination direction of each inner side surface should be such that the distance between the inner side surfaces becomes wider as the distance from the raceway surface between the pair of flanges increases. (D) When the central axis of the cylindrical roller is not parallel to the central axes of the inner ring and the outer ring, and the outer peripheral edge portions of both end surfaces of the cylindrical roller come into contact with the flanges, the contact points are different from each other. On the inside
Be located closer to the base end than the front edge of each tsuba.