JPH07174142A - Thrust roller bearing - Google Patents

Abstract

PURPOSE:To prevent increase of rotational torque and generation of wearing powder by preventing an axial directional end face of a holder from coming into sliding contact with axial directional one surface of a bearing ring to which this axial directional end face is opposed. CONSTITUTION:Dynamic pressure generating grooves 26, 26 are formed in axial directional one surface of a member which functions as a bearing ring such as a power roller 8. When this one surface is placed adjacent to an end face of a holder, a dynamic pressure is generated by these dynamic pressure generating grooves 26, 26, to prevent these one surface and end face from coming into sliding contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The thrust rolling bearing according to the present invention is used to support a thrust load applied to a power roller constituting a toroidal type continuously variable transmission, for example.

[0002]

2. Description of the Related Art The use of a toroidal type continuously variable transmission as schematically shown in FIGS. 9 to 10 has been studied as a transmission for an automobile or a transmission for various industrial machines. This toroidal type continuously variable transmission supports an input side disk 2 concentrically with an input shaft 1 and an output side disk at an end of an output shaft 3 as disclosed in Japanese Utility Model Laid-Open No. 62-71465. Four
Is fixed. An inner surface of a casing accommodating the toroidal type continuously variable transmission, or a support bracket provided in the casing, has pivots 5 and 5 in a twisted position with respect to the input shaft 1 and the output shaft 3 as a center. Swing trunnions 6, 6 are provided.

The trunnions 6, 6 are provided with the pivots 5, 5 on the outer surfaces of both ends. Further, the base ends of the displacement shafts 7, 7 are supported on the central portions of the trunnions 6, 6, and the trunnions 6, 6 are swung about the pivot shafts 5, 5, so that the displacement shafts 7, The inclination angle of 7 can be freely adjusted. Power rollers 8, 8 are rotatably supported around displacement shafts 7, 7 supported by the trunnions 6, 6, respectively. The power rollers 8, 8 are sandwiched between the input side and output side disks 2, 4.

The inner surfaces 2a, 4a of the input-side and output-side disks 2, 4 facing each other have arcuate concave surfaces whose cross sections are substantially centered on the pivot shaft 5, respectively. The peripheral surfaces 8a, 8a of the power rollers 8, 8 formed on the spherical convex surface are in contact with the inner side surfaces 2a, 4a.

A loading cam type pressing device 9 is provided between the input shaft 1 and the input side disk 2, and the pressing device 9 causes the input side disk 2 to face the output side disk 4 and elastically moves. Pressing. This pressing device 9
Is a cam plate 10 that rotates together with the input shaft 1, and a retainer 11.
A plurality of (for example, four) rollers 12 held by
It is composed of 12 and. On one side surface (left side surface in FIGS. 9 to 10) of the cam plate 10, a cam surface 13 which is an uneven surface extending in the circumferential direction is formed, and on the outer side surface of the input side disk 2 (FIGS. 9 to 10). On the right side) of the same cam surface 14
Is formed. Then, the plurality of rollers 12, 1
2 is supported rotatably about an axis in the radial direction with respect to the center of the input shaft 1.

When the toroidal type continuously variable transmission constructed as described above is used, when the cam plate 10 rotates as the input shaft 1 rotates, the cam surface 13 causes the plurality of rollers 12, 1 to rotate.
2 is a cam surface 14 formed on the outer surface of the input side disk 2.
Is pressed by. As a result, the input side disk 2 is pressed by the plurality of power rollers 8 and at the same time, the input side disk 2 is input based on the engagement between the pair of cam surfaces 13 and 14 and the plurality of rollers 12 and 12. The side disc 2 rotates.
Then, the rotation of the input side disk 2 is transmitted to the output side disk 4 via the plurality of power rollers 8 and the output shaft 3 fixed to the output side disk 4 rotates.

When the rotational speeds of the input shaft 1 and the output shaft 3 are changed, and when deceleration is first performed between the input shaft 1 and the output shaft 3, the trunnions 6, 6 centering on the pivot shafts 5, 5 are used.
As shown in FIG. 9, the peripheral surfaces 8a, 8a of the power rollers 8, 8 are moved toward the center of the inner side surface 2a of the input side disk 2 and the outer side of the inner side surface 4a of the output side disk 4. The displacement shafts 7, 7 are tilted so as to abut with and respectively.

On the other hand, when the speed is increased, the peripheral surfaces 8a, 8a of the power rollers 8, 8 are, as shown in FIG. 10, the outer side portion of the inner side surface 2a of the input side disk 2 and the output side disk. The displacement shafts 7, 7 are tilted so as to abut the center portion of the inner side surface 4a of the shaft 4. If the inclination angles of the displacement axes 7 and 7 are set in the middle between FIG. 9 and FIG.
An intermediate gear ratio can be obtained between the input shaft 1 and the output shaft 3.

FIGS. 9 to 10 show only the basic structure of a toroidal type continuously variable transmission, but a more specific structure as a transmission for automobiles is also disclosed in, for example, Japanese Utility Model Application No. 61-8752.
As described in the microfilm of No. 3 (Jitsukai Sho 62-199557), various types have been conventionally known.

By the way, during operation of the toroidal type continuously variable transmission as described above, the power rollers 8, 8 rotate at a high speed while receiving the thrust load from the input side disk 2 and the output side disk 4. Therefore, between each of the power rollers 8 and 8 and each of the trunnions 6 and 6 is shown in FIG.
A thrust rolling bearing 15 is provided as shown in FIG. The thrust rolling bearing 15 is currently being researched on the premise of using a thrust ball bearing. However, when the thrust load applied to each of the power rollers 8 increases due to an increase in the size of the toroidal type continuously variable transmission and an increase in power to be transmitted, a thrust taper roller bearing can be used. is there.

In any case, the above thrust rolling bearing 15
Is made of bearing steel, ceramics or the like, has the function of an inner ring, and has the central axis α.
And a plurality of rolling elements (balls or tapered rollers) 16, 16,
The cage 20 is configured to retain the plurality of rolling elements 16 and 16 in a rollable manner, and an outer ring 17 having a central axis that coincides with the central axis α of the power roller 8.
The plurality of rolling elements 16, 16 are made of bearing steel or ceramic. In addition, the power roller 8
An inner ring raceway 18 is formed on one axial surface (upper surface of FIG. 11) of the outer ring 17, and an outer ring raceway 19 is formed on a portion of the outer ring 17 on one axial direction (lower surface of FIG. 11) facing the inner ring raceway 18. There is. The rolling surfaces of the rolling elements 16, 16 are in rolling contact with the inner ring raceway 18 and the outer ring raceway 19, respectively.

Further, the cage 20 has a main body 21 made of metal or synthetic resin in the shape of a circular ring. This subject 2
Pockets 22 and 22 (circular in the illustrated example) that match the generatrix shape of the rolling elements 16 and 16 are formed at circumferentially equidistant positions in the diametrical middle portion. Then, the rolling elements 16 and 16 are attached to the pockets 22 and 22 respectively.
Each one is held so that it can roll freely. Further, the outer ring 17 made of bearing steel, ceramic or the like in a circular ring shape is abutted against the inner surface of each trunnion 6 via the spacer 23 also formed in a circular ring shape. Each of the pockets 22 and 22 has a spherical concave surface on one end inner peripheral surface (when the rolling elements 16 and 16 are balls), and a caulking portion protruding inward in the diameter direction at the other end opening edge portion, Each pocket 2
The rolling elements 16 and 16 are prevented from coming off from 2 and 22. However, the inner peripheral surface of each pocket 22, 22 may be simply a cylindrical surface.

During operation of the toroidal type continuously variable transmission, such thrust rolling bearing 15 rotates at high speed while bearing the thrust load applied to each of the power rollers 8, 8. Therefore, the peripheral surfaces 8a, 8a of the respective power rollers 8, 8 are present in the casing of the toroidal type continuously variable transmission.
And the inner side surfaces 2a, 4a of both the input side and output side disks 2, 4.
Lubrication of the thrust rolling bearing 15 by utilizing traction oil that enters into the space and contributes to the transmission of power has been conventionally studied as disclosed in, for example, Japanese Patent Laid-Open No. 1-275950.

The lubrication structure described in this publication ejects the traction oil toward the thrust rolling bearing 15 by a pump (not shown). The traction oil ejection path is provided inside the displacement shaft 7 in addition to the oil supply holes 24, 24 formed in a part of the outer ring 17, and is opened toward the inner peripheral surface of the cage 20. A hole or an oil supply hole provided in a separate portion and opened toward the outer peripheral surface of the cage 20 is considered.

During operation of the toroidal type continuously variable transmission, lubricating oil is forcibly fed into the oil supply holes 24, 24 by the pump. The lubricating oil forcedly fed into the oil supply holes 24, 24 flows through the gap between the both surfaces of the cage 20 and the inner ring raceway 18 and the outer ring raceway 19,
In the meantime, the rolling portions of the plurality of rolling elements 16, 16 are lubricated.

[0016]

In the case of the thrust rolling bearing having the above-mentioned structure, the retainer 20 can be slightly displaced in the axial direction. Further, the cage 20 and the power roller 8 rotate at high speed during operation. That is, the power roller 8 rotates based on the rotations of the input side and output side and both disks 2 and 4, and the retainer 20 rotates at about half the speed of the power roller 8 based on the revolution of the rolling elements 16 and 16. To do. Moreover, the outer ring 17 does not rotate. Therefore, the both axial end surfaces of the cage 20 and the axial one surface of the power roller 8 and the outer ring 17 relatively rotate at a high speed.

Even when the cage 20 relatively rotates at a high speed with respect to the power roller 8 and the outer ring 17 as described above, FIG.
As shown in (A), when the cage 20 is located between the inner surface of the outer ring 17 and the outer surface of the power roller 8, the axial end surface of the cage 20 and the surface facing this end surface rub against each other. There is no particular problem.

However, when the cage 20 is displaced in the axial direction, as shown in FIG.
If the inner end surface of the roller and the outer surface of the power roller 8 are in sliding contact with each other, or conversely, the outer end surface of the retainer 20 and the inner surface of the outer ring 17 are in sliding contact with each other, the following problems (1) to (4) occur.

Due to the friction on the sliding contact surface, the torque required to rotate the power roller 8 and the like increases, and the performance of the mechanical device incorporating the thrust rolling bearing, such as a toroidal type continuously variable transmission, deteriorates. Wear powder is generated on the sliding contact surface part, and this wear powder enters between the raceway surface and the rolling surface, which easily damages the raceway surface and the rolling surface, resulting in reliability and durability of the above-mentioned machinery. Cause to decrease.

The thrust rolling bearing of the present invention was invented in order to eliminate such inconvenience.

[0021]

The thrust rolling bearing of the present invention, like the conventionally known thrust rolling bearing,
A first bearing ring having a central axis, a first bearing surface formed on one axial surface of the first bearing ring, and a first bearing ring that rotates relative to the first bearing ring about the central axis. A second raceway ring, a second raceway surface formed on a portion of the second raceway ring on the axially opposite side opposite to the first raceway surface, and a circle at the diametrical intermediate portion of the ring-shaped main body. A cage provided with pockets at a plurality of positions in the direction, respectively, and provided between the first raceway surface and the second raceway surface so as to be rotatable relative to the first and second races. , And a plurality of rolling elements in which the respective rolling surfaces are brought into contact with the first and second raceway surfaces in a state where they are held rotatably inside the respective pockets.

In particular, in the thrust rolling bearing of the present invention, the axial one surface of the first bearing ring and the axial one surface of the second bearing ring are separated from the race surface formed on each one surface. A dynamic pressure generating groove for generating a dynamic pressure based on relative rotation between each bearing ring and the cage is provided.

[0023]

In the thrust rolling bearing of the present invention constructed as described above, the axial displacement of the cage causes the axial end surface of the cage to be axially one side of the first bearing ring or When approaching one axial surface of the second bearing ring, a dynamic pressure is generated between the end surface and one surface based on the action of the dynamic pressure generating groove formed on the one surface approaching the end surface, and these two surfaces are opposed to each other. To prevent sliding contact. As a result, it is possible to effectively prevent an increase in rotational torque and generation of abrasion powder due to the sliding contact.

[0024]

1 and 2 show a first embodiment of the present invention. The thrust rolling bearing of the present invention is characterized by a portion for preventing the axial end face of the cage and one axial face of the bearing ring from directly slidingly contacting each other. This is the same as the conventionally known thrust rolling bearing as incorporated in the toroidal type continuously variable transmission described above. Therefore, overlapping description will be omitted and the description will focus on the characteristic part of the present invention.

The power roller 8 for the toroidal type continuously variable transmission, which also has the function of the inner ring of the thrust rolling bearing, corresponds to the first bearing ring or the second bearing ring. An inner ring raceway 18 is formed at an intermediate portion in the diametrical direction (left-right direction in FIG. 2) of one surface (upper surface in FIG. 2) of the power roller 8 in the axial direction. The inner ring raceway 18 corresponds to the first raceway surface or the second raceway surface. Herringbone-shaped dynamic pressure generating grooves 26, 26 are formed in the ring-shaped portions 25a, 25b, which are located outside the inner raceway 18, between the diametrically outer portion and the inner portion of the one surface in the axial direction. is doing.

The power roller 8 having such dynamic pressure generating grooves 26, 26 formed on one side in the axial direction is combined with the rolling elements 16, 16, the outer ring 17, etc., as in the previously known structure. The thrust rolling bearing 15 (see FIG. 11) is configured. The outer ring 17 corresponds to the second bearing ring or the first bearing ring. In this case, a portion of the outer ring 17 on one side in the axial direction, which is out of the outer ring raceway 19, has a herringbone shape like the dynamic pressure generating grooves 26, 26, or a separate shape as described later. A dynamic pressure generating groove is formed in advance.

The power roller 8 having the dynamic pressure generating grooves 26, 26 formed on one surface in the axial direction as described above rotates clockwise in FIG. 1 during operation of the toroidal type continuously variable transmission. That is, the dynamic pressure generating grooves 26, 26 are formed in the direction toward the central bent portion toward the rear in the rotation direction.

In the case of the thrust rolling bearing of the present invention constructed by incorporating the power roller 8 (and the outer ring 17) having the dynamic pressure generating grooves 26, 26 as described above, the cage 2 is used.
Even if 0 is displaced in the axial direction, the axial end surface of the cage 20 and the one surface of the power roller 8 or the outer ring 17 do not come into sliding contact with each other. For example, when the axial end surface of the retainer 20 and one surface of the power roller 8 come close to each other based on the axial displacement of the cage 20, the dynamic pressure generating grooves 26, 26 formed on the one surface cause the end surface to move. And dynamic pressure is generated between one side and the other side.

That is, the lubricating oil existing between these end surfaces and one surface flows along the dynamic pressure generating grooves 26, 26 from both widthwise end portions of the ring-shaped portions 25a, 25b toward the central portion. . Then, the lubricating oil that has collided at the widthwise central portions of the ring-shaped portions 25a and 25b is sprayed from the one surface to the end surface. As a result, it is possible to prevent the one surface and the end surface from slidingly contacting each other, and it is possible to effectively prevent the rotation torque from increasing and the generation of abrasion powder due to the sliding contact.

Next, FIGS. 3 to 5 show a second embodiment of the present invention. Outer ring 1 that is the second or first orbital ring
An outer ring raceway 19, which is a second raceway or a first raceway, is formed in the diametrical (horizontal direction in FIG. 5) intermediate portion of one axial surface (lower surface in FIG. 5) of No. 7. Moreover, ratchet-shaped dynamic pressure generating grooves 28, 28 are formed in the ring-shaped portions 27a, 27b, which are located outside the outer raceway 19, in the diametrically outer portion and the inner portion of the one surface in the axial direction, respectively. is doing.

The cage 20 (see FIGS. 11 to 1) is attached to the outer ring 17 having the dynamic pressure generating grooves 28, 28 formed on the axial end faces thereof.
2) rotates in the direction of arrow X in FIG. 4 during operation of the toroidal type continuously variable transmission. When the axial end surface of the cage 20 and one surface of the outer ring 17 come close to each other, the lubricating oil existing between the end surface and the one surface of the outer ring 17 moves along the dynamic pressure generating grooves 28, 28 along the arrow Y in FIG. Flow in the direction. Then, the lubricating oil flowing out from the dynamic pressure generating grooves 28, 28 is sprayed from the one surface to the end surface. As a result, it is possible to prevent the one surface and the end surface from slidingly contacting each other, and it is possible to effectively prevent the rotation torque from increasing and the generation of abrasion powder due to the sliding contact.

Incidentally, the ratchet tooth-shaped dynamic pressure generating groove 2 described above is also formed on one axial surface of the inner ring of the power roller 8 or the like, which constitutes a thrust rolling bearing in combination with the outer ring 17.
It is free to form 8, 28.

Next, FIG. 6 shows a third embodiment of the present invention. In the case of this embodiment, spiral dynamic pressure generating grooves 29a, 29b are formed in the ring-shaped portions 25a, 25b on one side in the axial direction of the power roller 8 (and the outer ring 17). Of these dynamic pressure generating grooves 29a, 29b, the dynamic pressure generating grooves 29a, 29a formed in the annular portion 25a on the outer side in the diametrical direction start from the outer peripheral edge of the annular portion 25a, respectively.
It ends in the middle of 5a. Further, the dynamic pressure generating grooves 29b, 29b formed in the annular portion 25b on the inner side in the diametrical direction start from the inner peripheral edge of the annular portion 25b, respectively.
It ends in the middle of 5b. Also, which dynamic pressure generating groove 2
9a and 29b also incline toward the rear in the rotation direction of the power roller 8 from the start point toward the end point. In the example shown in FIG. 6, the power roller 8 rotates clockwise.

When the axial end surface of the retainer 20 approaches the one axial surface of the power roller 8 in which the dynamic pressure generating grooves 29a and 29b are formed, the lubricating oil existing between these end surfaces and one surface is It flows along the dynamic pressure generating grooves 29a and 29b. Then, the lubricating oil flowing out from the end points of the dynamic pressure generating grooves 29a and 29b is sprayed from the one surface to the end surface. As a result, it is possible to prevent the one surface and the end surface from slidingly contacting each other, and it is possible to effectively prevent the rotation torque from increasing and the generation of abrasion powder due to the sliding contact.

Depending on the application or assembly structure of the thrust rolling bearing, the cage 20 may be displaced not only in the thrust direction but also in the radial direction to a considerable extent. In such a case, if the inner peripheral surface of the retainer 20 is in sliding contact with the outer peripheral surface of the shaft, or the outer peripheral surface of the retainer 20 is in sliding contact with the inner peripheral surface of a member such as a housing provided around it. Again, problems such as a decrease in durability due to an increase in rotational torque and the generation of abrasion powder are likely to occur.

Therefore, in order to deal with such a problem, a dynamic pressure generating groove is formed on the inner peripheral surface of the retainer 20 or the outer peripheral surface of the shaft, or the outer peripheral surface of the retainer 20 or the inner peripheral surface of the housing or the like. A structure in which a dynamic pressure generating groove is formed on the surface can be implemented in combination with the present invention. In view of such circumstances, FIG. 7 shows dynamic pressure generating grooves 30, 30 formed on the inner peripheral surface of the cage 20, and FIG. 8 shows dynamic pressure generating grooves 32, 32 formed on the outer peripheral surface of the shaft 31. It was done. The dynamic pressure generating grooves 30 and 32 generate dynamic pressure between the inner peripheral surface and the outer peripheral surface based on the relative rotation between the cage 20 and the shaft 31, and the peripheral surfaces are in sliding contact with each other. Prevent things. If a similar dynamic pressure generating groove is formed on the outer peripheral surface of the retainer 20 or on the inner peripheral surface of the member 33 (FIG. 8) that faces the outer peripheral surface such as the housing, these both peripheral surfaces are in sliding contact with each other. Can be prevented.

As a method for forming the dynamic pressure generating groove in each member, the following methods (1) to (5) can be considered. When forming on metal members such as the power roller 8 and outer ring 17 (1) Etching (2) Electric discharge machining (3) Plastic machining According to the methods of (1) and (2) above, the machining cost is high, but the size is high. Accuracy can be obtained. On the other hand, according to the above method (3), the dimensional accuracy is slightly inferior, but the processing cost is low, and therefore the mass productivity is excellent. When forming the holder 20,
In addition to the processing methods of (1), (2), and (3), (4) die-cast molding (5) injection molding (4) is used when a dynamic pressure generating groove is formed in the metal cage 20. The method 5) can be used when forming the dynamic pressure generating groove in the cage 20 made of synthetic resin. The dynamic pressure generating grooves 26, 28, 29a, 29b, 30, 3
If 2 is formed in a corrugated shape (W shape), contact between the bearing ring and the cage can be prevented regardless of the rotation direction.

[0038]

Since the thrust rolling bearing of the present invention is constructed and operates as described above, it is possible to suppress the rotating torque to a low level and prevent remarkable wear and seizure to improve reliability and durability. You can

[Brief description of drawings]

FIG. 1 is a plan view of a power roller showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a bottom view of the outer ring showing the second embodiment of the present invention.

4 is a sectional view taken along line BB of FIG.

FIG. 5 is a sectional view taken along line CC of FIG.

FIG. 6 is a bottom view of the power roller showing the third embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a cage and rolling elements having dynamic pressure generating grooves formed on the inner peripheral surface.

FIG. 8 is a cross-sectional view showing a retainer and a rolling element combined with a shaft having a dynamic pressure generating groove formed on the outer peripheral surface.

FIG. 9 is a side view showing a basic configuration of a toroidal type continuously variable transmission incorporating a thrust rolling bearing in a state of maximum deceleration.

FIG. 10 is a side view showing the same state at the time of maximum acceleration.

FIG. 11 is a cross-sectional view of a thrust rolling bearing and a lubricating device portion thereof.

FIG. 12 is an enlarged view of an A portion of FIG. 11, showing a state where lubrication is performed favorably and a state where lubrication is poor in the apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input shaft 2 Input side disk 2a Inner side surface 3 Output shaft 4 Output side disk 4a Inner side surface 4b Outer side surface 5 Axis 6 Trunnion 7 Displacement axis 8 Power roller 8a Circumferential surface 9, 9a Pressing device 10, 10a Cam plate 11 Cage 12 Rollers 13 and 14 Cam surface 15 Thrust rolling bearing 16 Rolling body 17 Outer ring 18 Inner ring raceway 19 Outer ring raceway 20 Retainer 21 Main body 22 Pocket 23 Spacer 24 Oil supply hole 25a, 25b Ring portion 26 Dynamic pressure generating groove 27a, 27b Ring portion 28, 29a, 29b, 30 Dynamic pressure generating groove 31 Shaft 32 Dynamic pressure generating groove 33 Member

Claims (1)

[Claims] 1. A first bearing ring having a central axis, and a first bearing surface formed on one axial surface of the first bearing ring,
A second bearing ring that rotates relative to the first bearing ring about the central axis, and a second bearing ring formed on a portion of one axial surface of the second bearing ring that faces the first bearing surface. A second raceway surface, and a pocket provided in each of a plurality of circumferential locations in the diametrical intermediate portion of the ring-shaped main body, the first between the first raceway surface and the second raceway surface, A cage that is provided to freely rotate relative to the second both races, and a state in which the cage is held rotatably inside the pockets, and the rolling surfaces of the cages are set to the first and second sides, respectively. In a thrust rolling bearing provided with a plurality of rolling elements that are in contact with both raceway surfaces, each is formed on one side of the first raceway axial one side and the second raceway axial one side. Dynamic pressure is generated on the part deviated from the raceway surface based on the relative rotation between each bearing ring and the cage. Thrust rolling bearing, characterized in that provided with a pressure generating groove.