ROLLER AND CAGE ASSEMBLY AND PLANETARY GEAR SUPPORT STRUCTURE
20200362911 ยท 2020-11-19
Inventors
Cpc classification
F16C33/6681
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16C33/467
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H1/28
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H57/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16C19/463
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16C2361/61
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H2057/085
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16C19/34
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F16C19/34
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16C33/46
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H1/28
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A roller and cage assembly (1) includes a roller (2) and a cage (3). The cage has a plurality of annular portions (30), a plurality of pillars (31) that couple the plurality of annular portions, and a pocket (40) formed between adjacent pillars. The pillars include a protrusion (35) that protrudes from a side wall surface towards the pocket and contacts the roller, which side wall surface configures the pocket, and within the protrusion, a plane facing the roller in a circumferential direction has a first plane (36), and a second plane (37) connecting to the first plane, the first plane being a flat plane, and the second plane being a curved plane, or a flat plane inclined against the first plane.
Claims
1. A roller and cage assembly comprising a roller and a cage, wherein the cage has a plurality of annular portions, a plurality of pillars coupling the plurality of annular portions, and a pocket formed between adjacent ones of the pillars, the pillars include a protrusion protruding from a side wall surface toward the pocket and contacting the roller, the side wall surface configuring the pocket, within the protrusion, a plane facing the roller in a circumferential direction has a first plane, and a second plane connecting to the first plane, the first plane being a flat plane, and the second plane being a curved plane, or a flat plane inclined against the first plane.
2. The roller and cage assembly according to claim 1, wherein a border section where the first plane and the second plane meet is of a smooth arc form.
3. The roller and cage assembly according to claim 1, wherein the pillars include a pillar center portion located in a center region in an axial direction and relatively on an inner side in a radial direction, a pair of pillar end portions located on end regions in the axial direction and relatively on an outer side in the radial direction, and a pair of pillar inclined portions located between the pillar center portion and the pair of pillar end portions, the pillar end portions have a groove formed on an outer radial plane thereof configured to guide lubrication oil to the protrusion.
4. The roller and cage assembly according to claim 3, wherein a side end portion on the outer radial plane of the protrusion and the groove are in a positional relationship intersecting with each other.
5. The roller and cage assembly according to claim 1, wherein the roller has a crowning portion formed on each end thereof in the axial direction, the protrusion is provided having intervals therebetween in the axial direction, and the crowning portion is supported by an inclined flat plane of the first plane or the second plane.
6. A planetary gear support structure comprising: an internal gear; a sun gear disposed in a center of the internal gear; a plurality of planetary gears configured to mesh with the internal gear and the sun gear; and a carrier configured to support the planetary gear, wherein in the planetary gear support structure of a planetary gear mechanism in which the planetary gear is supported freely rotatable on a pinion shaft provided to the carrier via a rolling-element bearing, the rolling-element bearing being a roller and cage assembly according to claim 1.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DESCRIPTION OF EMBODIMENTS
[0032] An embodiment of the present invention is described in detail with reference to the drawings. Identical or equivalent portions within the drawings will be provided with identical reference symbols, and their descriptions will not be repeated.
Overview of Planetary Gear Mechanism
[0033] First described is an overview of a planetary gear mechanism (planetary gear) 100 in which a roller and cage assembly 1 according to the present embodiment is used, with reference to
[0034] The planetary gear mechanism 100 is, for example, used in a transmission for an automobile, and the roller and cage assembly 1 is used as a rolling-element bearing to support a pinion gear (pinion shaft) 103 in the planetary gear mechanism 100 in a rotatable manner. Namely, the roller and cage assembly 1 according to the present embodiment is a roller and cage assembly for automobiles.
[0035] The planetary gear mechanism 100 includes a ring gear (internal gear) 101 having inner teeth and which encircles an outer periphery, a sun gear 102 having external teeth and which is disposed at the center of the ring gear 101, and a plurality of pinion gears (planetary gears) 103 having external teeth and which are disposed between the ring gear 101 and the sun gear 102. The pinion gears 103 mesh with the ring gear 101 and the sun gear 102, and are supported in a rotatable manner to a pinion shaft 105 set in an engagement hole, by the roller and cage assembly 1. Each of the pinion shafts 105 are disposed (coupled) to a carrier 104, and rotations equivalent to the revolution of the pinion gears 103 are inputted to and outputted from the carrier 104.
[0036] With reference to
[0037] An oil passage hole 106 for feeding lubrication oil is formed inside the pinion shaft 105. By guiding the lubrication oil to the outer peripheral surface of the pinion shaft 105 via the oil passage hole 106 formed inside the pinion shaft 105 as such, the roller 2 becomes lubricated. More specifically, the oil passage hole 106 includes a first oil passage hole 106a extending in an axial direction from the right side shown in
[0038] When the planetary gear mechanism 100 is used in a transmission for an automobile whose stages are increasing in number, the amount of lubrication oil fed to the roller and cage assembly 1 may be reduced, or lubrication oil with low viscosity may be fed, to further increase the fuel economy of the automobile. Kinematic viscosity of the lubrication oil is, for example, 2 centistokes (cSt) to 8 centistokes (cSt) at 100 C.
Embodiment 1
[0039] Next describes the roller and cage assembly 1 according to the present embodiment, with reference to
[0040] The pillars 31 of the present embodiment include a pillar center portion 32 positioned relatively on an inner side in the radial direction of its axial direction center region, a pair of pillar end portions 33 positioned relatively on outer sides in the radial direction of its axial direction end regions, and a pair of pillar inclined portions 34 positioned between the pillar center portion 32 and each of the pair of pillar end portions 33. The pair of pillar end portions 33 are provided in the axial direction with intervals therebetween, for the number of the pillar center portions 32 and the pair of pillar inclined portions 34. The width in the circumferential direction of the pillar inclined portion 34 is smaller than the width in the circumferential direction of the pillar center portion 32.
[0041] As particularly shown in
[0042] Particularly referring to
[0043] Further with reference to
[0044] Further with reference to
[0045] Next describes, with reference to
[0046] Moreover, as shown in
[0047] As such, according to the cage 3 of the roller and cage assembly 1 according to the present embodiment, the roller 2 can be supported by the flat plane 36 in the normal state (state in which the roller 2 is not skewed), and the roller 2 can be supported by the curved plane 37 in a state in which the roller 2 is skewed; it is thus possible to prevent the roller 2 from abrading and the cage 3 from abrading, in both the normal state and the skewed state. As a result, it is possible to prolong a lifetime of the roller and cage assembly 1.
[0048] In recent years, transmissions for automobiles are increasing in stages for fuel economy of the automobiles, and such transmissions tend to employ a planetary gear mechanism. Moreover, in addition to the increase in stages for further fuel economy, the transmissions for automobiles tend to reduce the amount of lubrication oil and to employ a lubrication oil with low viscosity. Therefore, even by using the roller and cage assembly 1 according to the present embodiment to the planetary gear mechanism for transmissions under an environment in which an oil film is difficult to be formed, it is possible to prolong a lifetime of the roller and cage assembly 1.
[0049] Moreover, by forming the groove 38, the lubrication oil that exists on a region surrounded by the outer periphery of the cage 3 and the outer peripheral surface of the pinion shaft 105 of the pinion gear 103 can be efficiently guided to the protrusions 35; this allows for efficiently feeding the lubrication oil to the roller 2. This accordingly can prevent the oil film on the outer peripheral surface of the roller 2 from breaking, even if the fed amount of the lubrication oil is reduced or the kinematic viscosity of the lubrication oil is reduced, for fuel economy.
[0050] As such, by the protrusions 35 having the first plane (flat plane) 36 and the second planes (curved planes) 37, and having the groove 38 being formed on the outer diameter planes of the pillar 31, it is possible to further prevent the abrasion of the protrusion 35 of the cage 3 and the roller 2, and can maintain the surface roughness of the roller 2 in a normal state. This thus causes no contact on minute protrusions in surface roughness shapes between the roller 2 and the protrusion 35, thus preventing minute peeling of the roller 2 and major peeling starting from the minute peeling. Accordingly, it is possible to prolong the lifetime of the roller and cage assembly 1.
[0051] One example of a manufacturing method of the roller and cage assembly 1 of the present embodiment will be described.
[0052] First, prepare a steel plate in strip form. As the material for the steel plate in strip form, for example low carbon steel, low alloy steel, or carburized steel may be used to ensure strength of the cage 3. The steel plate in strip form is press-roll formed so that its cross-sectional shape becomes M-shaped, and is subjected to a pocket opening processing for forming the pocket 40 that supports the roller 2. Next, on the pillar end portions 33 of the pillar 31, the protrusion 35 having the flat plane 36 and the pair of curved planes 37, and the groove 38 are formed. These processings are carried out by fixing the outer diameter surface of the pillar end portions 33 of the pillar 31 and deburring by pressing from the inner diameter surface side.
[0053] Thereafter, the steel plate in strip form is cut to have a length of the circumference of the cage 3, and the cut steel plate in strip form is rounded into a ring shape. Thereafter, the rounded steel plate in strip form is welded on both its ends, to manufacture the cage 3. This welding is performed by, for example, carbon gas arc welding, argon gas arc welding, or electric resistance welding. To the pocket 40 of the cage 3 manufactured as such, a plurality of the rollers 2 are incorporated, to manufacture the roller and cage assembly 1.
[0054] Accordingly, the processing of the flat plane 36 and the curved planes 37 of the protrusion 35 can use the same conventional facilities and can be manufactured in substantially the same speed as before; there is thus no need to introduce new facilities, and can be made to have the same manufacturing costs as the traditional metal cages. Moreover, by making the cage 3 made of metal, it is possible to hold down manufacturing costs as compared to a cage made of resin, which is inferior in manufacturing speed.
Embodiment 2
[0055] With reference to
[0056] The roller and cage assembly 1A of the present embodiment is one used in the planetary gear mechanism 100 similarly to Embodiment 1. In particular, the roller and cage assembly 1A uses a helical gear as the pinion gear 103. By using the helical gear, a couple of forces will apply on the roller and cage assembly, thus making the roller in an environment easy to skew.
[0057] As shown in
[0058] The roller 2A of the present embodiment has been crowned, as shown in
[0059] Next describes operations of the roller and cage assembly 1A, with reference to
Embodiment 3
[0060] A roller and cage assembly 1B according to Embodiment 2 will be described with reference to
[0061] The roller and cage assembly 1B of the present embodiment is one used in the planetary gear mechanism 100 as with Embodiment 1, and in particular, uses a spur gear as the pinion gear 103 in such as a planetary gear mechanism for construction machines. By using the spur gear, no couple of forces are applied on the roller and cage assembly, thus making the roller 2A difficult to skew.
[0062] As shown in
[0063] As shown in
[0064] As shown in
[0065] In the above embodiment, the grooves 38, 38A, 38B are provided for facilitating the guiding of the lubrication oil to the protrusions 35, 35A, 35B, however these are not limited to the shape in the above embodiments. The grooves are sufficient as long as at least a portion thereof continues to the pillar end portions 33, 33A, 33B, and there is no need for the entire groove to be located within the pillar end portions 33, 33A, 33B.
[0066] Moreover, in the above embodiment, the roller and cage assemblies 1, 1A, 1B are described as a roller and cage assembly of a single row. This however may be a roller and cage assembly with a plurality of rows.
[0067] Moreover, in the above embodiment, needle rollers are used as the rollers 2, 2A that are housed in the pocket 40. However, it is not limited to this, and for example may be a cylindrical roller, a stick roller or the like.
[0068] Moreover, in the above embodiment, the cages 3, 3A, 3B are so-called M-shaped cages having a plurality of annular portions. However, it is not limited to this, and may be so-called V-shaped cages that do not have the plurality of annular portions 30.
[0069] The embodiments disclosed in the present specification is only exemplary in all aspects, and should be considered not limitative. The scope of the present invention is shown not by the above descriptions but by the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.
REFERENCE SIGNS LIST
[0070] 1, 1A, 1B Roller and cage assembly
[0071] 2, 2A Roller
[0072] 3, 3A, 3B Cage
[0073] 21, 21A Crowning portion
[0074] 30 Annular portion
[0075] 31 Pillar
[0076] 32 Pillar center portion
[0077] 33, 33B Pillar end portion
[0078] 34 Pillar inclined portion
[0079] 35, 35A, 35B Protrusion
[0080] 36, 36B Flat plane (First plane)
[0081] 36A Inclined flat plane (First plane)
[0082] 37, 37A Curved plane (Second plane)
[0083] 37B Inclined flat plane (Second plane)
[0084] 38, 38A, 38B Groove
[0085] 39, 39A, 39B Border section
[0086] 40 Pocket
[0087] 100 Planetary gear mechanism
[0088] 102 Sun gear
[0089] 103 Pinion gear (planetary gear)
[0090] 104 Carrier
[0091] 105 Pinion shaft