JP2018179009A - Thrust cylindrical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce a friction loss between cylindrical rollers and cage pockets while taking into consideration a guide clearance which is necessarily required between a cage and bearing rings.SOLUTION: A thrust roller bearing comprises: an annular first bearing ring and an annular second bearing ring which are oppositely arranged so as to be relatively rotatable; an annular cage arranged between the first bearing ring and the second bearing ring, and having a plurality of pockets which are formed with intervals in a circumferential direction; and cylindrical rollers which are accommodated in the pockets of the cage. A pair of side faces which oppose in the circumferential direction of the cage pockets are inclined to a radial direction of the cage so as to extend along a longitudinal direction of an external peripheral face of the cylindrical roller which is inclined most largely out of the cylindrical rollers which are accommodated in the pockets so as to be oriented to rotation centers of the bearing rings when a rotation center of the cage is displaced by an amount of the guide clearance with respect to the rotation centers of the first and second bearing rings.SELECTED DRAWING: Figure 2

Description

  The present invention relates to, for example, thrust cylindrical roller bearings used in automobiles and industrial machines, and more particularly, to thrust cylindrical roller bearings suitable for rotary supports such as automobile transmissions and automobile air conditioner compressors.

  2. Description of the Related Art Conventionally, thrust cylindrical roller bearings having features such as high rigidity, high capacity, and compactness have been used for rotary support portions of automobile transmissions and automobile air conditioner compressors. The thrust cylindrical roller bearing also includes a thrust needle bearing using a needle whose axial dimension is larger than the outer diameter dimension of the rolling element, whereas in the following description, it is referred to simply as a "bearing". In some cases.

  FIG. 6 shows an example of a transmission for an automobile using such a thrust cylindrical roller bearing described in Patent Document 1. The illustrated transmission TM includes a planetary gear G1 for acceleration, a sun gear constituting a planetary gear G2, a carrier for supporting a pinion, a ring gear, and three clutches C1, C2 and C3 and a brake B1 or B2 2 By changing the combination of engagement and non-engagement states of the two brakes, the sixth forward gear and the first reverse gear can be achieved.

  At this time, helical gears are used as the gears constituting both planetary mechanisms G1 and G2 in order to increase the meshing ratio of the gears. Therefore, when power is transmitted from the gear to the gear, an axial load acts in the axial direction of the gear. In order to support such axial loads, the illustrated transmission uses seven thrust cylindrical roller bearings, bearings BG1 to BG7.

  By the way, in such a thrust cylindrical roller bearing, as shown in FIG. 7, differential slip and skew due to the peripheral speed difference occur (see Patent Document 2). This is because the peripheral speed on the outer diameter side of the bearing ring is faster than the rotation speed of the cylindrical roller 104, and the peripheral speed on the inner diameter side is slower than this. When such differential slip or skew occurs, the friction loss between the cylindrical roller 104 and the bearing ring or the friction loss due to the cylindrical roller 104 coming into contact with the side surface 103s of the rectangular pocket 103p of the cage 103 As a result, rotational torque may increase.

  In order to reduce the friction loss due to the contact between the cylindrical roller and the side surface of the pocket, Patent Document 3 discloses that the shape of the pocket 203p is trapezoidal as shown in FIG. An arrangement is disclosed in which the extension of the centerline CL of the roller 204 passes through the axis O of the holder 203 when it abuts 203s.

JP, 2010-249261, A JP, 2008-261476, A JP, 2010-249261, A

  By the way, the shape of the pocket 203p shown in FIG. 8 is derived focusing on only the relationship between the holder 203 and the roller 204 accommodated in the pocket 203p. However, in order to reduce the friction loss between the cylindrical roller and the cage pocket, it is necessary to consider the behavior of the cylindrical roller when a thrust cylindrical roller bearing is actually incorporated into a product such as a transmission.

  That is, since the cage needs to rotate relative to the race around the rotation center of the bearing together with the cylindrical roller, the cage necessarily needs a predetermined gap (guide gap) for the race. Therefore, the cage rotates while accommodating the cylindrical roller in the pocket in a state where the rotation center is displaced with respect to the rotation center of the bearing ring (= bearing) by the maximum guide gap. Therefore, in order to effectively reduce the friction loss between the cylindrical roller and the cage pocket, it is more preferable to have a cage pocket shape in which the guide clearance is taken into consideration. The reduction of the friction loss leads to the reduction of the torque, and the reduction of the torque leads to the fuel saving and the reduction of the load on the global environment.

  In view of the above-mentioned circumstances, the present invention effectively reduces the friction loss between the cylindrical roller and the cage pocket in consideration of the guide clearance which is always required between the cage and the bearing ring. It is an object of the present invention to provide a thrust cylindrical roller bearing capable of reducing the torque as a total bearing.

（３）前記保持器ポケットは、外径側端面の長さが内径側端面の長さよりも長い略台形状とされている（１）または（２）記載のスラスト円筒ころ軸受。
（４）前記保持器は、前記第１の軌道輪側に位置する第１の保持部材と、前記第２の軌道輪側に位置し前記第１の保持部材と係合する第２の保持部材とを有する（１）〜（３）の何れかに記載のスラスト円筒ころ軸受。 The above object of the present invention is achieved by the following constitution.
(1) ring-shaped first race rings and second race rings disposed so as to be relatively rotatably opposed;
An annular cage disposed between the first race and the second race and having a plurality of circumferentially spaced apart pockets;
Cylindrical rollers housed in the pockets of the cage;
A thrust cylindrical roller bearing provided with
When the center of rotation of the cage is spaced apart from the centers of rotation of the first and second races by a guide gap, a pair of circumferentially opposed side surfaces of the cage pocket are located. To be inclined with respect to the radial direction of the cage so as to extend along the outer peripheral surface longitudinal direction of the most inclined cylindrical roller among the cylindrical rollers accommodated in the pocket so as to face the rotation center of Thrust cylindrical roller bearings characterized by
(2) Annular first race rings and second race rings disposed oppositely rotatably
An annular cage disposed between the first race and the second race and having a plurality of circumferentially spaced apart pockets;
Cylindrical rollers housed in the pockets of the cage;
A thrust cylindrical roller bearing provided with
Assuming that a pair of side surfaces opposed in the circumferential direction of the cage pocket has a guide clearance C and a pitch circle diameter of the cage pocket is PCD, at least the following formula ( A thrust cylindrical roller bearing characterized by being inclined by an angle θ or more satisfying 1).

(3) The thrust cylindrical roller bearing according to (1) or (2), wherein the cage pocket has a substantially trapezoidal shape in which the length of the outer diameter side end face is longer than the length of the inner diameter side end face.
(4) The holder is a first holding member positioned on the first raceway side, and a second holding member positioned on the second raceway side and engaged with the first holding member A thrust cylindrical roller bearing according to any one of (1) to (3).

  According to the invention as set forth in claim 1 of the present application, a pair of side surfaces opposed in the circumferential direction of the cage pocket is divided by the guide clearances with respect to the centers of rotation of the cage with respect to the centers of the first and second races. Said holding so as to extend along the outer peripheral surface longitudinal direction of the most inclined cylindrical roller among said cylindrical rollers housed in said pocket so as to face the rotation center of said bearing ring when it is positioned as far as By being inclined relative to the radial direction of the container, the friction loss between the cylindrical roller and the pocket under the most severe conditions can be reduced, so that the total friction loss between the cylindrical roller and the cage pocket can be reduced.

According to the invention described in claim 2 of the present application, when the pair of side surfaces facing each other in the circumferential direction of the cage pocket has a guide clearance C and the pitch circle diameter of the cage pocket is PCD, the cage Between the cylindrical roller and the race while reducing the overall friction loss between the cylindrical roller and the cage pocket by inclining at least an angle θ satisfying the following equation (1) with respect to the radial direction of In addition, the friction loss of the thrust cylindrical roller bearing as a whole can be reduced.

It is a sectional view of a thrust cylindrical roller bearing of an embodiment of the present invention. It is A arrow line view of FIG. 1 which abbreviate | omitted the bearing ring. It is explanatory drawing which showed the relationship of the trapezoidal cage pocket and cylindrical roller of embodiment of this invention. It is explanatory drawing which showed the relationship between the conventional rectangular-shaped retainer pocket and cylindrical roller. It is a figure which shows the result of having carried out simulation calculation of the relationship between the inclination angle of the pocket side and bearing torque. It is a figure which shows an example of the conventional transmission for motor vehicles. It is a figure explaining the differential slip between a cylindrical roller and a bearing ring. It is explanatory drawing which showed an example of the conventional trapezoid-shaped retainer pocket and cylindrical roller.

    Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate.

  As shown in FIG. 1, the thrust cylindrical roller bearing 10 includes an annular first bearing ring 1 and a second bearing ring 2 disposed so as to be relatively rotatably opposed, and the first bearing ring 1 and the second bearing ring 2. And an annular cage 3 disposed between the bearing ring 2 and the plurality of circumferentially spaced pockets 3p, and a cylindrical roller housed in the pocket 3p of the cage 3 4 and.

  The first bearing ring 1 is an annular member having an L-shaped cross section which can be attached (for example, fitted, press-fit) to one member M1 of the pair of members M1 and M2 which rotate relative to each other. The first bearing ring 1 is positioned substantially in contact with the one member M1 and extends in the radial direction of the bearing 10, and is bent substantially at right angles from the outer peripheral edge of the first body 1a. And a first lip portion 1 b extending in the axial direction of the bearing 10. When the first main body portion 1a incorporates the thrust cylindrical roller bearing 10 between the relatively rotating members M1 and M2, the outer surface 1s thereof is attached to one member M1, and the inner side surface (second bearing ring 2 The first raceway surface 1r which is continuous along the circumferential direction is formed on the facing surface facing the surface 1). The cylindrical roller 4 rolls on the first raceway surface 1r.

  The second race 2 is an annular member having an L-shaped cross section that can be mounted (for example, fitted, press-fit) on the other member M2 that rotates relatively. The second bearing ring 2 is positioned in contact with the other member M 2 and extends in the radial direction of the bearing 10, and the first bearing ring 1 from the inner peripheral edge of the second body portion 2 a It has a second lip 2 b which is bent substantially at right angles to the side and extends in the axial direction of the bearing 10. When the second main body portion 2a incorporates the thrust cylindrical roller bearing 10 between the relatively rotating members M1 and M2, the outer surface 2s is attached to the other member M2, and the inner side surface (first bearing ring 1) The second raceway surface 2r continuous along the circumferential direction is formed on the facing surface facing the surface of the second track surface 2r. The cylindrical roller 4 rolls on the second raceway surface 2r.

  The cage 3 holds the plurality of cylindrical rollers 4 at intervals in the circumferential direction. In the present embodiment, an annular first cage (first holding member) 3out having a pair of square C-shaped cross sections that can be overlapped in a state of facing each other and a second cage (first 2 holding members) 3 in. The first cage 3 out is disposed on the side of the first race 1, and the second cage 3 in is disposed on the side of the second race 2 in a state of facing the first cage 3 out. There is. As shown, the second holder 3 in is housed and superimposed in the first holder 3 out. In the first cage 3 out and the second cage 3 in, pockets 3 p for holding the cylindrical roller 4 are formed at intervals in the circumferential direction. The pockets 3p of the first retainer 3out and the second retainer 3in are formed to have the same phase in the circumferential direction.

  In each pocket 3p, as shown in FIG. 2, the length of the inner end face 3i is shorter than the length of the outer end face 3j, and the pair of opposing side faces 3s are inclined at an angle θ with respect to the radial direction of the cage. It has a substantially trapezoidal shape. The inclination angle θ of the pair of side surfaces 3s will be described in detail later.

  The cylindrical roller 4 has a circular cross-sectional shape and has a predetermined length. The plurality of cylindrical rollers 4 are respectively held in the pockets 3p of the cage 3 described above. In addition, an elongated cylindrical roller having a small diameter and a length of 3 to 10 times the diameter is referred to as a needle roller.

  In a state where the above-described thrust cylindrical roller bearing 10 is incorporated between the relatively rotating members M1 and M2, the cylindrical roller 4 has a cylindrical outer peripheral rolling surface 4s on the first raceway surface 1r and the second raceway surface 2r. It can rotate while being in contact with it. In this state, when the two members M1 and M2 rotate relative to each other, that is, the first race 1 and the second race 2 rotate relative to each other, the plurality of cylindrical rollers 4 form the first raceway surface 1r and the second raceway surface. By rolling along with 2r, both members M1 and M2 can continue to rotate smoothly relative to each other.

  During relative rotation of the first race 1 and the second race 2, the cage 3 revolves around the center of the bearing, and as described above, between the cylindrical roller 4 and the races 1, 2 Differential slip and skew occur due to the circumferential speed difference. The present invention has a pocket shape that can reduce the friction loss between the cylindrical roller 4 and the pocket 3p even when such a skew occurs.

  FIG. 3 is a diagram showing a state in which a skew occurs. In FIG. 3, the bearing ring (not shown) rotates in the CW direction, which is relatively clockwise, and the rotation center O2 of the cage 3 is in the X direction in the figure with respect to the rotation center O1 of the bearing ring. Shows a state shifted by 1/2 of. In FIG. 3 and FIG. 4 described later, in order to make the description easy to understand, a line extending in the radial direction from the cage rotation center is indicated by a solid line, and a line extending in the radial direction from the bearing ring rotation center is indicated by a two-dot chain line. doing. Here, the guide gap C is an essential dimension for rotating the cage 3 relative to the bearing ring, and the bearing guide surface of the bearing ring (the first lip portion 1 b of FIG. 1 and The diameter of the opposite surface (in the case of the outer ring guide) or the surface (in the case of the inner ring guide) opposite to the second lip 2b and the diameter of the guide surface of the cage (the first lip 1b outer diameter or the second lip 2b 3 shows a state where the cage has moved the most in the X direction in the figure (moving distance = C / 2) from the state where the centers of rotation coincide with each other.

  As shown in FIG. 3A, the center of rotation O1 of the bearing ring (the description of the bearing ring is omitted and only the center of rotation is shown) and the center of rotation O2 of the cage 3 are one of the guide gaps C in the X direction. When skew occurs in each cylindrical roller 4 when the cylinder roller 4 deviates by 1/2, each cylindrical roller 4 tries to move to the position where its own axis, which is the most stable position, faces the rotation center O1 of the bearing ring, Move to the state of 3 (b).

  At this time, the cylindrical roller 4a, which is located at the circumferential center in FIG. 3 (b), extends from the rotation center O2 of the cage 3 straight on the line extending in the Y direction in the figure. It is in the most inclined state. However, since the side surface 3s of the pocket 3p is inclined by θ with respect to the radial direction of the cage 3, the outer peripheral surface 4s of the cylindrical roller 4a opposes the side surface 3s in a state of being able to gently abut in the longitudinal direction. For this reason, the friction loss between the cylindrical roller 4a and the cage pocket 3p can be kept small.

  The cylindrical rollers 4b and 4c positioned on the left or right in the drawing with respect to the most inclined cylindrical roller 4a in the drawing have a smaller inclination than the cylindrical roller 4a, so the outer peripheral surface 4s of the cylindrical roller 4 and the pocket The friction loss with the side 3s is smaller. Therefore, if the axis of the most inclined cylindrical roller 4a is oriented to the rotation center O1 of the bearing ring, the friction loss between the outer peripheral surface of the cylindrical roller 4 and the pocket side surface 3s can be minimized as a whole of the bearing 10. it is conceivable that.

The inclination angle θa of the pocket side surface 3s when the outer peripheral surface of the most inclined cylindrical roller 4a abuts gently with the pocket side surface 3s in the longitudinal direction, the maximum guide clearance C and the pitch circle diameter of the cage pocket PCD Sometimes, it has the relationship of the following formula (2). Accordingly, the inclination angle θa is an angle θa that satisfies at least the following formula (3) with respect to the radial direction of the cage 3.
The pocket PCD (pitch circle diameter) is the diameter of a circle when the midpoint between the pocket inner diameter and the pocket outer diameter measured in the radial direction is continuous in the circumferential direction. It is the dimension represented by diameter) / 2.

  FIG. 4 is an explanatory view of a state in which the cylindrical roller 4 is skewed in the case of the pocket 303p of the conventional rectangular shape in contrast to the present invention. Similarly to FIG. 3, when a skew occurs in each cylindrical roller 4 when the center of rotation O2 of the cage is shifted by 1/2 of the guide clearance C with respect to the center of rotation O1 of the bearing ring, FIG. In each of the cylindrical rollers 4 in the state of {circumflex over (5)}, the most stable position of the cylindrical roller 4 tries to move to the position where its axis line faces the rotation center O1 of the bearing ring, and shifts to the state of FIG.

  However, since the pair of side surfaces 303s of the pocket 303p extends in parallel with the radial direction of the cage 303, the outer peripheral surface 4s of the cylindrical roller 4 which is going to move to the stable position has a pair of side surfaces 303s of the pocket Will be pushed relatively strongly.

  Next, calculation (simulation) results performed by the inventor in order to confirm the effect of tilting the pocket side surface 3s by the above angle θa will be described. In this calculation, for a thrust cylindrical roller bearing having the following specifications, the relationship between the inclination angle of the pocket side surface with respect to the cage radial direction and the bearing torque is calculated using simulation software.

Analysis conditions Bearings Thrust cylindrical roller bearings Roller diameter 2 mm
Roller length 2.6mm
Number of rollers 18 Pocket PCD 25.6 mm
Maximum guide clearance 0.205 mm
Operating condition Axial load 1100N
6500 rpm

  FIG. 5 shows the result of calculation performed under the above conditions. The horizontal axis in FIG. 5 indicates the ratio of the inclination angle of the pocket to the value of θa calculated based on the above equation (3), and the vertical axis indicates the magnitude of the torque generated in the bearing. It is. Also, bearing torque mainly includes torque based on the friction loss between the cylindrical roller and the cage pocket and torque based on the friction loss between the cylindrical roller and the bearing ring. The breakdown of losses is also included. The bearing torque is displayed as a relative value based on the value (= 1.0) when the inclination angle is θa.

  As is clear from FIG. 5, it is confirmed that the friction loss between the cylindrical roller and the cage pocket becomes the smallest when the inclination θ of the trapezoidal pocket side face takes the value of θa calculated by the above equation (3). did it.

  However, the bearing torque indicating the friction loss of the entire bearing is smallest when the inclination angle θ of the pocket side surface is 1/2 of θa. Under this condition, as is clear from FIG. 5, the friction loss between the cylindrical roller and the cage pocket is larger than that in the case where the inclination angle is θa. However, the friction loss between the cylindrical roller and the bearing ring is improved. This is considered to indicate that limiting the inclination angle (skew) of the cylindrical roller to some extent is effective in reducing the friction loss between the cylindrical roller and the race. And, because the friction loss between the cylindrical roller and the cage pocket and the friction loss between the cylindrical roller and the bearing ring are most balanced, the total bearing torque is smaller than when the inclination angle is θa. It is thought that

  Further, it can be seen from FIG. 5 that the bearing torque as a whole hardly changes even if the value of the inclination angle θ becomes 2 to 5 times θa and θa.

For this reason, it can be said that the value of the inclination angle θ is preferably an angle represented by the following formula (4), that is, an angle represented by the formula (4) or more, which is at least 1/2 times θa. .

  Therefore, when focusing on the friction loss between the cylindrical roller and the cage pocket in order to reduce the bearing torque, the pair of circumferentially opposed side surfaces of the cage pocket has the center of rotation of the cage, The most inclined cylindrical roller among the cylindrical rollers housed in the pocket so as to face the rotation center of the bearing ring when it is spaced apart from the rotation centers of the first and second bearing rings by a guide gap It is understood that it is effective to be inclined with respect to the radial direction of the cage (inclination angle is θa) so as to extend along the outer peripheral surface longitudinal direction of the above.

  In addition, when focusing on the friction loss (the friction loss between the cylindrical roller and the cage pocket, and the friction loss between the cylindrical roller and the bearing ring) as the total bearing, the inclination angle θ is at least 1/1 / a of θa. If it is 2 times or more, it turns out that it is effective.

  The present invention is not limited to the ones exemplified in the above embodiment, and can be appropriately modified without departing from the scope of the present invention. For example, instead of using the two holding members of the first holding member and the second holding member, the holder bends one holding member several times in the radial direction to hold the cylindrical rollers. Such a cage may be used. Further, the cage pocket shape having a substantially trapezoidal shape may be extended in the circumferential direction with a constant curvature with any of the end faces instead of the linearly extending inner end face and the outer end face. Good.

  In addition, the inclination angle of the side surface of the pocket calculated by the equation (3) is a value considered to be the most preferable value when the technical idea of the present invention is pressed down. It is not to be beyond the scope of the invention.

1 first bearing ring 2 second bearing ring 3 cage 4 cylindrical roller 10 thrust cylindrical roller bearing

Claims (4)

First and second annular races arranged to be relatively rotatably opposed;
An annular cage disposed between the first race and the second race and having a plurality of circumferentially spaced apart pockets;
Cylindrical rollers housed in the pockets of the cage;
A thrust cylindrical roller bearing provided with
When the center of rotation of the cage is spaced apart from the centers of rotation of the first and second races by a guide gap, a pair of circumferentially opposed side surfaces of the cage pocket are located. To be inclined with respect to the radial direction of the cage so as to extend along the outer peripheral surface longitudinal direction of the most inclined cylindrical roller among the cylindrical rollers accommodated in the pocket so as to face the rotation center of Thrust cylindrical roller bearings characterized by First and second annular races arranged to be relatively rotatably opposed;
An annular cage disposed between the first race and the second race and having a plurality of circumferentially spaced apart pockets;
Cylindrical rollers housed in the pockets of the cage;
A thrust cylindrical roller bearing provided with
Assuming that a pair of side surfaces opposed in the circumferential direction of the cage pocket has a guide clearance C and a pitch circle diameter of the cage pocket is PCD, at least the following formula ( A thrust cylindrical roller bearing characterized by being inclined by an angle θ or more satisfying 1).

  The thrust cylindrical roller bearing according to claim 1 or 2, wherein the cage pocket has a substantially trapezoidal shape in which the length of the outer diameter side end face is longer than the length of the inner diameter side end face. The cage has a first holding member positioned on the first raceway side, and a second holding member positioned on the second raceway side and engaged with the first holding member. A thrust cylindrical roller bearing according to any one of claims 1 to 3.

Images