JP2006194292A - Thrust roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce excessive wear caused by a centrifugal force acting on each of rollers 2a, 2b. <P>SOLUTION: At a plurality of positions in a circumferential direction, pockets 9a, 9b for holding the rollers 2a, 2b, respectively, are provided radially in a plurality of rows. Besides, the axial length a<SB>0</SB>of each of the outside rollers 2b, 2b in the axial direction of a retainer 3b is made shorter compared to axial lengths a<SB>i</SB>of the inside rollers 2a, 2a in the same direction of the retainer (a<SB>0</SB><a<SB>i</SB>). As a result, the centrifugal force acting on each of the rollers 2b, 2b positioned outside can be reduced and thereby the wear of sliding portions can be reduced between outside end faces of each of the rollers 2b, 2b positioned outside in the axial direction of a retainer 3b and inside faces of pockets 9b, 9b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  A thrust roller bearing (including a thrust needle bearing) according to the present invention is mounted on a rotating part of, for example, an automobile transmission or a torque converter, and supports a thrust load applied between a pair of members opposed in the axial direction. However, it is used to freely rotate these two members.

  For example, a thrust roller bearing 1 as shown in FIG. 3 is mounted on a rotating portion of a transmission, a torque converter, a car cooler compressor, or the like to support a thrust load applied to a rotating shaft or the like (for example, Patent Document 1). reference). The thrust roller bearing 1 includes a plurality of rollers 2 arranged in a radial direction, a cage 3 that is formed in an annular shape as a whole, and holds the rollers 2 in a freely rolling manner, and the rollers 2 are pivoted. It consists of an outer ring 4 and an inner ring 5 that are sandwiched from both sides in the direction (left-right direction in FIG. 3). The outer ring 4 and the inner ring 5, each corresponding to a bearing ring member described in the claims, are each provided with a ring-shaped race portion 6 that is in rolling contact with the rollers 2.

  The cage 3 is formed by combining a pair of elements 7a and 7b, each of which is U-shaped in cross section with a metal plate, and is formed in an annular shape as a whole. The annular portions 8 and 8 of the elements 7a and 7b are respectively provided with window holes 10 and 10 in the radial direction for constituting the same number of pockets 9 as the rollers 2. And the said holder | retainer 3 is comprised by combining each element 7a, 7b which provided such window holes 10 and 10 in the state with which the phase of these each window holes 10 and 10 corresponds. In addition to the cage 3 formed by combining such a pair of elements 7a and 7b in the middle, an annular main portion made of, for example, a synthetic resin penetrates both axial sides. A cage having a pocket is also known in the art.

  When the thrust roller bearing 1 configured as described above is used, the outer flange 11 configuring the outer ring 4 is fitted in the holding portion 13 of the casing 12, for example, in the axial direction of the race portion 6 of the outer ring 4. The side surface is brought into contact with the step portion 14 of the casing 12. At the same time, the other axial side surface of the race portion 6 of the inner ring 5 is brought into contact with, for example, a step portion 16 of the shaft 15. In this state, the shaft 15 is rotatably supported with respect to the casing 12, and a thrust load acting between the shaft 15 and the casing 12 can be supported.

  By the way, when the thrust roller bearing 1 as described above is used, each of the rollers 2 receives a centrifugal force toward the radially outer side (upper side in FIG. 3) of the cage 3 as indicated by an arrow α in FIG. Join. Based on such centrifugal force, each of the rollers 2 has an end face (outer end face) outside in the radial direction of the cage 3 among both end faces in the axial direction (vertical direction in FIG. 3). In a state where it is strongly pressed against the inner surface (opening edge of the window holes 10 and 10) of the pocket 9 facing (sliding contact), it revolves while rotating. For this reason, based on such pressing, the portion of the inner surface of each pocket 9 that is in sliding contact with the outer end surface of each roller 2 may be excessively worn.

  In order to prevent such excessive wear, Patent Document 2 describes an invention in which the frictional resistance of the sliding contact portion between the end surface of each roller and the inner surface of each pocket is reduced. That is, one or more rollers (in the radial direction of the cage) are provided in each pocket of the cage constituting the thrust roller bearing, and the accuracy (surface roughness) of both end surfaces in the axial direction of these rollers is provided. ) Is described. However, by regulating the surface roughness of both end faces of each roller in this way, the centrifugal force applied to each roller cannot be reduced even if the frictional resistance of the sliding contact portion is reduced. For this reason, it is considered that the effect of preventing excessive wear based on the centrifugal force applied to each roller as described above cannot be sufficiently obtained only by regulating the surface roughness (decreasing the frictional resistance). .

On the other hand, in Patent Document 3, as shown in FIGS. 4 to 5, pockets 9 and 9 for holding the rollers 2 and 2 respectively are arranged in two rows in the radial direction at a plurality of locations in the circumferential direction of the cage 3a. And a thrust roller bearing 1a in which each of the rollers 9, 2 is provided in each of the pockets 9, 9. In the case of such a conventional structure, for example, the axial length of the rollers 2 and 2 per roller is shortened as compared with a thrust roller bearing having the same diameter, in which each roller is provided in a row in the radial direction of the cage. And weight reduction. However, in the case of the structure described in Patent Document 3, the axial length a _o of the rollers 2 and 2 positioned outside in the radial direction of the cage 3a is set to the rollers 2 and 2 that are also positioned inside. The axial slip length a _{i is} greater than or equal to (a _o ≧ a _i ), and by adopting such a configuration, the differential slip of the rollers 2 and 2 is reduced.

  However, the centrifugal force applied to each of the rollers 2 and 2 increases as the rollers 2 and 2 become heavier (the longer the axial length is as long as the material and outer diameter are the same), and further from the center of revolution. The larger the distance is, the greater the distance is located on the outer side in the radial direction of the cage 3a. For this reason, in the case of the structure described in Patent Document 3 as described above, even if the differential slip can be reduced, the centrifugal force applied to the rollers 2 and 2 positioned on the outer side in the radial direction of the retainer 3a is reduced. It cannot be small enough. If the centrifugal force applied to the outer rollers 2 and 2 cannot be made sufficiently small in this way, the portions of the inner surfaces of the pockets 9 and 9 that are in sliding contact with the outer end surfaces of the outer rollers 2 and 2 are the same. The inner rollers 2 and 2 may be excessively worn as compared with the portion in sliding contact with the outer end surfaces.

JP 2000-266043 A JP 2004-156744 A JP 2003-156050 A

  The thrust roller bearing of the present invention has been invented to realize a structure capable of reducing excessive wear based on the centrifugal force applied to each roller in view of the above-described circumstances.

The thrust roller bearing of the present invention includes a bearing ring member, a plurality of rollers, and a cage, like the conventional thrust roller bearing described above.
Of these, the race ring member includes an annular race portion having a raceway on one side in the axial direction. In addition, the respective rollers are in rolling contact with the raceways in the state of being arranged in the radial direction.
The retainer is in the shape of a ring and holds the rollers in a rollable manner.
This cage is provided with a plurality of pockets (two or more rows) in the radial direction at a plurality of locations in the circumferential direction for holding the rollers.
In particular, in the thrust roller bearing of the present invention, the axial length of each of the rollers is made smaller in the axial direction than in the inner side in the radial direction of the cage. .

  As described above, in the case of the thrust roller bearing according to the present invention, the axial lengths of the rollers positioned on the outer side in the radial direction of the cage, that is, the rollers far from the revolution center, are also positioned on the inner side. Each roller, that is, the length in the axial direction of each roller closer to the center of revolution is made smaller. For this reason, it is possible to reduce the centrifugal force applied to each of the rollers positioned on the outside, and the outer end surfaces (the end surfaces on the outer side in the radial direction of the cage of the two axial end surfaces) and the pockets of the rollers positioned on the outside. Wear of the sliding contact portion with the inner surface can be reduced.

  In addition, the above rollers are shifted in the circumferential direction in addition to overlapping in the radial direction (the phases in the circumferential direction are matched) with those located on the outside as well as those located on the inside in the radial direction (circumferential direction Can be shifted). Moreover, what overlaps in the radial direction and what is shifted can be mixed. In any case, if the axial length of each roller is made smaller on the side farther from the revolution center (rotation center of the cage), the centrifugal force applied to each roller on this far side can be reduced, and the above-mentioned It is possible to reduce the wear of such sliding contact parts.

Preferably, when carrying out the present invention, as described in claim 2, the density of the rollers positioned inside in the radial direction of the cage is ρ _i , the axial length is also a _i , and the radius ( ½ of the outer diameter is denoted by r _i , the distance between the center of gravity and the center of revolution is denoted by R _i, and the density of the rollers positioned outside in the radial direction of the cage is denoted by ρ _o , and the axial length is also the same. It was a a _o is likewise radius (half the outer diameter) and r _o, also the distance between the center of gravity and the center of revolution in the case of the _{R o, 0.9 ≦ {ρ i} a i (r i R _i ) ² } / {ρ _o a _o (r _o R _o ) ² } ≦ 1.1. More preferably, 0.95 ≦ {ρ _i a _i (r _i R _i ) ² } / {ρ _o a _o (r _o R _o ) ² } ≦ 1.05.

  If comprised in this way, the amount of wear of the sliding contact part of the axial direction outer end surface (end surface outside on the radial direction of the cage) and the inner surface of the pocket located on the outer side with respect to the radial direction of the cage, The amount of wear at the sliding contact portion between the outer end surface of the roller positioned at the inner surface of the pocket and the inner surface of the pocket can be made the same level (so that there is no great difference in the amount of wear at both portions). In other words, the wear amount of the sliding contact portion located on the outer side is obviously larger than the wear amount of the sliding contact portion located on the inner side, or conversely, the wear amount of the sliding contact portion located on the inner side. It is possible to prevent the amount of wear from becoming significantly larger than the amount of wear of the sliding contact portion located on the outside, and to make wear uniform as a whole. In addition, the lifetime can be optimized (long life). Hereinafter, this reason will be described with reference to FIGS. 1 and 2 showing an embodiment of the present invention.

  The degree of wear (amount of wear) of the sliding contact portion between the outer end surface of each roller 2a, 2b (the outer end surface with respect to the radial direction of the cage 3b) and the inner surface of each pocket 9a, 9b is applied to each sliding contact portion. It is determined by the product of the force and the sliding speed (so-called PV value). In other words, the product of the centrifugal force applied to each of the rollers 2a and 2b and the peripheral speed of the outer end surface of each of the rollers 2a and 2b affects the amount of wear of the sliding contact portion (product of the centrifugal force and the peripheral speed). The larger the is, the greater the amount of wear of the sliding contact portion).

Here, the mass of each roller 2a, 2a (referred to as each inner roller 2a, 2a) located inside with respect to the radial direction of the cage 3b is m _i , and each roller 2b, 2b located outside (each outside) The mass of the rollers 2b and 2b) is m _o , the revolution angular velocity of both the inner and outer rollers 2a and 2b is ω, and the center of gravity G _i and the center of revolution O of each of the inner rollers 2a and 2a as described above. distance R _i and, if the outside of each roller 2b, the distance between the center of gravity G _o and revolution center O of 2b and R _o, these inner, a centrifugal force F _i applied outside the rollers 2a, 2b, F _o Can be expressed by the following equations (1) and (2).
F _i = m _i R _i ω ^2- (1)
F _o = m _o R _o ω ² --- (2)

Further, as described above, the density of the inner rollers 2a, 2a is ρ _i , the axial length is a _i , the radius is r _i, and the density of the outer rollers 2b, 2b is ρ _o. likewise if the axial length a _o, like the radius r _o, these inner, outer the rollers 2a, the mass m _i of 2b, m _o respectively, expressed by (3) (4) below.
m _i = ρ _i a _i πr _i ^2- (3)
_{m o = ρ o a o πr} o 2 --- (4)

Further, when the rotational angular velocity of the inner rollers 2a and 2a is ω _i and the rotational angular velocity of the outer rollers 2b and 2b is ω _o , the peripheral speeds V _i and V _{o of the} inner and outer rollers 2a and 2b are set. Can be expressed by the following equations (5) and (6).
V _i = r _i ω _i --- (5)
V _o = r _o ω _o --- (6)
Further, when it is considered that the inner and outer rollers 2a and 2b are revolving without rotating, the above equations (5) and (6) can be expressed by the following equations (7) and (8).
V _i = r _i ω _i = R _i ω −−− (7)
V _o = r _o ω _o = R _o ω −−− (8)

As described above, the ease of wear of the sliding contact portion is affected by the product of the centrifugal force applied to each roller 2a, 2b and the peripheral speed of each roller 2a, 2b. Therefore, the wear amount of the sliding contact portion between the outer end surfaces of the inner rollers 2a and 2a and the inner surfaces of the pockets 9a and 9a, and the outer end surfaces of the outer rollers 2b and 2b and the inner surfaces of the pockets 9b and 9b In order to make the wear amount of the sliding contact portion approximately the same, the above-described product relating to the inner rollers 2a, 2a and the above-described product relating to the outer rollers 2b, 2b may be set to the same degree. In other words, as shown in the following formula (9), the ratio of the product related to the inner rollers 2a, 2a and the product related to the outer rollers is within a range of 0.9 to 1.1 ( Within the range of ± 10%), more preferably within the range of 0.95 to 1.05 (within the range of ± 5%), the amount of wear at each sliding contact portion can be made comparable. .
0.9 ≦ (F _i V _i ) / (F _o V _o ) ≦ 1.1 (9)

  When the ratio of the products is smaller than 0.9 (more preferably 0.95), the amount of wear of the sliding contact portions related to the outer rollers 2b and 2b is set to the inner rollers 2a and 2a. There is a possibility that the amount of wear of the sliding contact portion will be too much. On the other hand, when the product ratio is larger than 1.1 (more preferably 1.05), the amount of wear of the sliding contact portion related to the inner rollers 2a and 2a is larger than the outer rollers. There is a possibility that the amount of wear of the sliding contact portion related to 2b and 2b becomes too much. For this reason, the product ratio is regulated as shown in the above equation (9).

Then, by solving such equation (9) using the above equations (3) to (8), the following equation (10) is obtained.
0.9 ≦ {(m _i R _i ω ² ) (r _i ω _i )} / {(m _o R _o ω ² ) (r _o ω _o )} ≦ 1.1
0.9 ≦ {(m _i R _i ω ² ) (R _i ω)} / {(m _o R _o ω ² ) (R _o ω)} ≦ 1.1 0.9 ≦ (m _i R _i ² ) / (M _o R _o ² ) ≦ 1.1
_{0.9 ≦ {(ρ i a i} πr i 2) R i 2} / {(ρ o a o πr o 2) R o 2} ≦ 1.1
0.9 ≦ {ρ _i a _i (r _i R _i ) ² } / {ρ _o a _o (r _o R _o ) ² } ≦ 1.1 −−− (10)

Here, when the materials of the inner and outer rollers 2a and 2b are the same, that is, when the density is the same (ρ _i = ρ _o ), the following equation (11) is obtained.
0.9 ≦ {a _i (r _i R _i ) ² } / {a _o (r _o R _o ) ² } ≦ 1.1 (11) In such a case, these rollers 2a, 2b The relationship between the axial lengths a _i and a _o , the radii r _i and r _{o of} these rollers 2a and 2a, and the distances R _i and R _o from the revolution center O satisfies the above-mentioned formula (11). If it regulates like this, the wear amount of the sliding contact portion between the outer end surfaces of the inner rollers 2a, 2a and the inner surfaces of the pockets 9a, 9a, the outer end surfaces of the outer rollers 2b, 2b and the pockets 9b, The amount of wear of the sliding contact portion with the inner surface of 9b can be made comparable. If the wear amount can be made similar to the above, the wear amount of the sliding contact portion located on the outer side becomes larger than the wear amount of the sliding contact portion located on the inner side. This prevents the amount of wear of the sliding contact portion from increasing compared to the amount of wear of the sliding contact portion located outside, and optimizes the life (long life) by making the wear uniform as a whole. I can plan.

If the radii r _i and r _{o of the} inner and outer rollers 2a and 2a are the same (r _i = r _o ), the following equation (12) is obtained.
0.9 ≦ (a _i R _i ² ) / (a _o R _o ² ) ≦ 1.1 (12)
In such a case, the axial lengths a _i and a _{o of the} rollers 2a and 2b and the distances R _i and R _o from the revolution center O are regulated so as to satisfy the above expression (12). To do. In this case, since the relationship between the distances R _i and R _o from the revolution center O is R _i <R _o , the axial lengths of the outer rollers 2b and 2b in order to satisfy the above expression (12). a _o is made smaller (a _i > a _o ) than the axial length a _i of the inner rollers 2a, 2a.

Moreover, the case where the materials of the inner and outer rollers 2a and 2b are different, that is, the densities are different (ρ _i ≠ ρ _o ) is also conceivable. Specifically, for example, the outer rollers 2b and 2b may be made of ceramic, and the inner rollers 2a and 2a may be made of steel. In such a case, depending on the density ρ _i , ρ _o , the axial length a _o of the outer rollers 2b, 2b is set to the inner rollers 2a, 2a in order to satisfy the equation (10). May be larger (a _i <a _o ) than the axial length a _i . However, it is inevitable that the ceramic roller is more expensive than the steel roller. At the same time, due to the difference in thermal expansion coefficient between ceramic and steel, rolling contact between the roller made of steel (inner rollers 2a, 2a) having a large thermal expansion amount and the bearing ring member when the temperature rises during operation. There is also a possibility that the contact pressure of the part becomes excessively high. For this reason, as described above, it is not realistic to make only the outer rollers 2b and 2b ceramic.

  1 and 2 show an embodiment of the present invention. The feature of this embodiment is that the size and the like of each of the rollers 2a and 2b are restricted in order to reduce the wear based on the centrifugal force applied to each of the rollers 2a and 2b. Since the structure and operation of the other parts are the same as those of the conventional structure shown in FIG. 3 and FIGS. 4 to 5 described above, overlapping illustrations and explanations are omitted or simplified. Explained.

In the case of the present embodiment, the pockets 9a and 9b for holding the rollers 2a and 2b are provided in a plurality of circumferential directions (12 locations) and in a double row (two rows) in the radial direction. Yes. At the same time, the axial length a _o of the outer rollers 2b, 2b in the radial direction of the cage 3b is smaller than the axial length a _i of the inner rollers 2a, 2a (a _o <A _i ). Furthermore, in the case of the present embodiment, the densities ρ _i and ρ _{o and the} radii r _i and r _o of the inner and outer rollers 2a and 2b are the same (ρ _i = ρ _o , r _i = r _o ). At the same time, the distance between the center of gravity G _i of each of the inner rollers 2a, 2a and the revolution center O is R _i , and the distance between the center of gravity G _o of each of the rollers 2b, 2b located outside and the revolution center O is R _o. In this case, 0.9 ≦ (a _i R _i ² ) / (a _o R _o ² ) ≦ 1.1, more preferably 0.95 ≦ (a _i R _i ² ) / (a _o R _o ² ) The distances R _i and R _{o and the} axial lengths a _i and a _o are regulated so as to satisfy ≦ 1.05.

As described above, in the case of the present embodiment, the axial lengths a of the rollers 2b, 2b positioned on the outer side in the radial direction of the cage 3b, that is, the rollers 2b, 2b on the side far from the revolution center O. _o is smaller than the axial length a _i of the rollers 2a, 2a that are also located on the inner side, that is, the rollers 2a, 2a closer to the revolution center O. For this reason, it is possible to reduce the centrifugal force applied to each of the rollers 2b, 2b located on the outside, and the outer end surfaces of the rollers 2b, 2b located on the outside (with respect to the radial direction of the cage 3b among the axial end surfaces). The wear of the sliding contact portion between the outer end surface) and the inner surfaces of the pockets 9b and 9b can be reduced.

Moreover, in this embodiment, as described above, ρ _i = ρ _o , r _i = _ro and 0.9 ≦ (a _i R _i ² ) / (a _{o Ro} ² ) ≦ The size of each part is regulated so as to be 1.1. For this reason, the wear amount of the sliding contact portion between the outer end surfaces of the inner rollers 2a and 2a and the inner surfaces of the pockets 9a and 9a, the outer end surfaces of the outer rollers 2b and 2b, and the pockets 9b and 9b The amount of wear at the sliding contact portion with the inner surface can be made comparable. The reason why the wear amount can be made similar to this is as described in the above-mentioned section “Best Mode for Carrying Out the Invention”. As a result, the wear amount of the slidable contact portions related to the rollers 2b and 2b located on the outer side is larger than the wear amount of the slidable contact portions related to the rollers 2a and 2a located on the inner side, or conversely. The wear amount of the slidable contact portions related to the rollers 2a and 2a located on the inner side is prevented from being increased as compared with the wear amount of the slidable contact portions related to the rollers 2b and 2b located on the outer side. The life can be optimized (long life) by making it even.

  In the present embodiment, the rollers 2a and 2b are provided in two rows in the radial direction of the cage 3b, but may be two or more rows. In the case of the present embodiment, the rollers 2a and 2b are overlapped in the radial direction between the one located on the inner side and the outer side on the radial direction of the cage 3b (in the circumferential direction). Are in phase). On the other hand, although illustration is omitted, it is possible to shift in the circumferential direction (shift in the phase in the circumferential direction) between the one located inside and the outside located in the radial direction. Moreover, what is superimposed in the radial direction and what is displaced can be mixed. In any case, if the axial length of each roller is made smaller on the side farther from the center of revolution, the centrifugal force applied to each roller on this far side can be reduced, and excessive sliding contact as described above can be achieved. Wear can be reduced.

The figure similar to FIG. 5 which shows the Example of this invention and shows a holder and each roller. AA sectional drawing of FIG. The fragmentary sectional view shown in the state which assembled | attached the conventional thrust roller bearing to the use location. Sectional drawing which shows another example of the conventional thrust roller bearing. The figure seen from the side which removed any bearing ring member and removed this bearing ring member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a Thrust roller bearing 2, 2a, 2b Roller 3, 3a, 3b Cage 4 Outer ring 5 Inner ring 6 Race part 7a, 7b Element 8 Annulus part 9, 9a, 9b Pocket 10 Window hole 11 Outer flange 12 Casing 13 Holding Part 14 Step part 15 Axis 16 Step part

Claims (2)

  A race ring member having a ring-shaped race portion having a raceway on one side in the axial direction, a plurality of rollers in which the respective rolling surfaces are brought into rolling contact with the raceway in a state of being arranged in a radial direction, and each of these rollers A ring-shaped cage that holds the roller in a freely rollable manner, and this cage is provided with pockets for holding each of the rollers in a plurality of rows in the circumferential direction in double rows in the radial direction. A thrust roller characterized in that, in a thrust roller bearing, the axial length of each of the rollers is smaller at the outer side in the radial direction of the cage than at the inner side. bearing. The density of the rollers located on the inner side with respect to the radial direction of the cage is ρ _i , the axial length is also a _i , the radius is also r _i , and the distance between the center of gravity and the revolution center is R _i , the density of the roller located outside with respect to the radial direction of the above retainer and [rho _o, likewise the axial length and a _o, same radius as r _o, also if the distance between the center of gravity and the center of revolution was R _o The thrust roller bearing according to claim 1, wherein 0.9 ≦ {ρ _i a _i (r _i R _i ) ² } / {ρ _o a _o (r _o R _o ) ² } ≦ 1.1.

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