JP2007100771A - Thrust cylindrical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a structure capable of suppressing wear of an outer peripheral side peripheral portion of each pocket 7 provided in a cage 2a.
The cage 2a is made of chrome molybdenum steel, a oxynitride layer is formed on the surface, and the surface hardness is set to Hv 600 or more. Further, the roller protrusion amount δ ₁ is made smaller than the width dimension W in the radial direction of the chamfered portion 11 of the cylindrical roller 8, and the negative roller drop amount δ ₂ and the radial direction of the chamfered portion 11 are related. The difference from the width dimension W is made smaller than the plate thickness T of the metal plate constituting the cage 2a. Thereby, the said subject can be solved.
[Selection] Figure 2

Description

  The present invention relates to an improvement of a thrust cylindrical roller bearing incorporated in a rotation support portion of various mechanical devices such as an automobile transmission, a car air conditioner compressor, and a machine tool. Specifically, the wear of the cage of the thrust cylindrical roller bearing is reduced, and a structure having excellent durability is realized. The thrust cylindrical roller bearing that is the subject of the present invention includes a thrust needle bearing that uses a needle (needle roller) having a larger axial dimension than the outer diameter as a rolling element. Therefore, the cylindrical roller described in the present specification and claims includes the needle.

  As a thrust cylindrical roller bearing provided with a cage that can be manufactured at a low cost by punching and bending a single metal plate, techniques described in Patent Documents 1 to 5 are known. 4 to 8 show a thrust cylindrical roller bearing 1 of a first example having a conventional structure, which is known as described in each of these patent documents. The thrust cylindrical roller bearing 1 includes one cage 2 and a plurality of cylindrical rollers 8 and 8. The cage 2 is integrally formed by bending a metal plate such as a steel plate, and has a cylindrical inner diameter side rim portion 4, a cylindrical outer diameter side rim portion 5, and an intermediate plate portion 6. And a plurality of pockets 7,7.

  Among these, the inner diameter side rim portion 4 is present at the inner peripheral edge portion of the cage 2 and has an annular shape continuous over the entire circumference. Further, the outer diameter side rim portion 5 is present on the outer peripheral edge portion of the cage 2 and has an annular shape that is concentric with the inner diameter side rim portion 4 and is continuous over the entire circumference. Further, the intermediate plate portion 6 exists between the inner diameter side rim portion 4 and the outer diameter side rim portion 5, and the cross-sectional shape is bent with respect to the radial direction. Further, each of the pockets 7 and 7 is formed in the intermediate plate portion 6 intermittently in the radial direction with respect to the circumferential direction, and holds the cylindrical rollers 8 and 8 in a freely rollable manner inside each. To do.

As shown in FIG. 5, a central flat surface 9 extending in a direction perpendicular to the rotation center axis of each cylindrical roller 8, 8, and the central flat surface 9 A chamfered portion 11 having a partially conical convex surface shape or a convex curved surface shape having a partially convex arc shape is formed, which continues the outer peripheral edge and the rolling surface 10 over the entire circumference. In the case of the conventional structure, among the dimensions of the chamfered portion 11, the axial dimension L ₈ and the radial dimension W _{8 of} each cylindrical roller 8 are substantially equal (L ₈ ≈W ₈ ). Further, in the intermediate plate portion 6, the portions between the pockets 7, 7 adjacent in the circumferential direction are column portions 12, 12.

  The intermediate plate portion 6 includes a central flat plate portion 13, an outer diameter side flat plate portion 14, an inner diameter side flat plate portion 15, an inner diameter side continuous portion 16, and an outer diameter side continuous portion 17. Among these, the central flat plate portion 13 is a portion closer to one end in the axial direction (the lower end of FIGS. 4, 6 and 8) in the middle in the radial direction (the left-right direction in FIGS. 4 and 6, the up-and-down direction in FIG. Is formed. Further, the outer diameter side flat plate portion 14 is formed at a portion near the other end in the axial direction (upper end in FIGS. 4, 6 and 8) adjacent to the radially inner side (left side in FIG. 6) of the outer diameter side rim portion 5. Has been. Further, the inner diameter side flat plate portion 15 is formed at a portion near the other end in the axial direction adjacent to the radially outer side (right side in FIG. 6) of the inner diameter side rim portion 4. The outer diameter side and inner diameter side flat plate portions 14 and 15 are located on the same plane. Further, the inner diameter side continuous portion 16 continues the outer peripheral edge of the inner diameter side flat plate portion 15 and the inner peripheral edge of the central flat plate portion 13, and the outer diameter side continuous portion 17 is an outer periphery of the central flat plate portion 13. The peripheral edge and the inner peripheral edge of the outer diameter side flat plate portion 14 are made continuous. The distance between the inner diameter side and outer diameter side continuous portions 16 and 17 increases as the distance from the central flat plate portion 13 increases. The outer surface of the central flat plate portion 13 (the lower surface in FIGS. 4, 6 and 8) and the leading edges of the inner diameter side and outer diameter side rim portions 4 and 5 are located on the same plane or the central flat plate portion. The outer surface of the portion 13 protrudes in the axial direction from the tip edge.

  The cage 2 configured as described above is a pair of race surfaces constituting the thrust cylindrical roller bearing 1 in a state where the cylindrical rollers 8 and 8 are rotatably held in the respective pockets 7 and 7. It is sandwiched between a pair of parallel planes facing each other in the axial direction. Among the flat plate portions 13 to 15 constituting the intermediate plate portion 6, the circumferential edge portions of the column portions 12 and 12 are the inner diameter side and the outer diameter side. Compared to the side edge portions of both continuous portions 16 and 17, they protrude slightly into the pockets 7 and 7.

  That is, in the outer diameter side flat plate portion 14 at the radially outer position and the inner diameter side flat plate portion 15 at the radially inner position, the circumferential end edges of the column portions 12 and 12 are respectively set on the outer diameter side. The locking portions 18 and 18 and the inner diameter side locking portions 19 and 19 are provided. Then, as shown in FIGS. 6 and 8 (A), these outer diameter side and inner diameter side locking portions 18 and 19 (described in “Axis of the peripheral portion of each pocket near the other end in the axial direction” Part of each cylindrical roller 8 is engaged with the rolling surface 10 of each cylindrical roller 8 so that a part of each cylindrical roller 8 becomes the outer surface of the central flat plate portion 13 and both the inner diameter side and outer diameter side rim portions. In other words, the outer edge of the central flat plate portion 13 and the leading edges of the inner and outer diameter side rim portions 4 and 5 are the opposite races so as to protrude in the axial direction from the leading edges of the pins 4 and 5. The axial displacement of the cage 2 toward one end side in the axial direction (the lower side in FIGS. 6 and 8) is restricted so as not to contact the surface.

Further, in the central flat plate portion 13 at the intermediate position in the radial direction, the circumferential edge portions of the column portions 12 and 12 are set as central locking portions 20 and 20, respectively. And as shown to (B) of FIG. 6, 8, these center latching | locking parts 20 and 20 (equivalent to "the axial direction one end side part of the peripheral part of each pocket" described in Claim 1), Due to the engagement of each cylindrical roller 8 with the rolling surface 10, a part of each cylindrical roller 8 remains in a state of protruding in the axial direction from both the outer diameter side and inner diameter side flat plate portions 14, 15. In other words, the other axial end of the cage 2 is such that the outer surfaces (the upper surfaces in FIGS. 4, 6 and 8) of both the outer diameter side and inner diameter side flat plate portions 14 and 15 do not contact the mating race surface. The axial displacement to the side (the upper side of FIGS. 6 and 8) is restricted.
In short, in a state where the cylindrical rollers 8 and 8 are held in the pockets 7 and 7, the locking portions 18 to 20 and the rolling surfaces 10 of the cylindrical rollers 8 and 8 are engaged with each other. The axial displacement of the cage 2 with respect to the cylindrical rollers 8 and 8 is suppressed. That is, the positioning of the cage 2 in the axial direction is achieved by so-called roller guides (both side rollers are provided).

  By the way, when the thrust cylindrical roller bearing 1 as described above is used, a force directed radially outward of the cage 2 is applied to the cylindrical rollers 8 and 8 based on the centrifugal force. And by this force, the outer diameter side end surface 21 which becomes the radial direction outer side of the cage 2 among the axial direction both end surfaces of the cylindrical rollers 8, 8, of the peripheral portions of the pockets 7, 7, The retainer 2 is pressed against the outer peripheral side peripheral edge 22 which is the radially outer side. As a result, the outer diameter side peripheral edge portion 22 and the outer diameter side end face 21 rub against each other at the portion indicated by the oblique lattice in FIG. However, the outer diameter side end face 21 is not uniformly pressed against the outer diameter side peripheral edge 22. In an actual case, the outer diameter side end surface 21 is pressed against the outer diameter side peripheral edge portion 22 due to the skew of the cylindrical rollers 8, 8 in the pockets 7, 7. In contact with each other.

  In other words, when the thrust cylindrical roller bearing 1 is operated, it is ideal that the direction of the rotation axis of each of the cylindrical rollers 8 and 8 and the radial direction of the cage 2 coincide with each other. However, in actual cases, it is inevitable that a skew occurs in which these two directions do not coincide with each other. Such a skew is caused by the friction coefficient of the rolling contact portion between the rolling surface 10 of each of the cylindrical rollers 8 and 8 and the race surface being non-uniform in the length direction of the rolling contact portion. Further, the degree of contact between the outer diameter side end face 21 and the outer diameter side peripheral edge 22 becomes more significant as the deviation angle (skew angle) in both directions increases.

  While the cylindrical rollers 8 and 8 are skewed, a boundary portion between the outer peripheral edge portion of the central flat surface 9 and the chamfered portion 11 and the outer diameter side peripheral edge portion 22 in the outer diameter side end surface 21. When the two rub against each other, local stress concentration occurs in the rubbed portion (the contact surface pressure P increases), and rubs at a high rub-off speed V (the PV value that is a parameter associated with wear increases). Furthermore, it becomes difficult to form an oil film for lubrication in the rubbing portion, and metal contact is likely to occur in the rubbing portion. As a result, when the recessed portion 23 is formed in a part of the cage 2 at the outer peripheral side peripheral edge portion 22 as shown in FIG. There is. On the other hand, cold rolled steel sheet (SPCC) is widely used as a material for the cage 2. Further, in order to increase the surface hardness of the cage 2, nitriding treatment has been conventionally performed. By subjecting the SPCC material to nitriding treatment, the surface hardness can be increased to about Hv500, but even if the surface hardness of the cage 2 is about Hv500, It may not be possible to sufficiently prevent the formation of the concave recess 23.

  When such a recessed portion 23 becomes large to some extent, a chamfered portion 11 provided on the outer peripheral edge of the retainer 2 in the radial direction at a part of each of the cylindrical rollers 8, 8 is formed in the recessed portion 23. While entering, a so-called submergence occurs that is displaced radially outward of the cage 2 from the original position of the pockets 7 and 7. When such subsidence occurs, the sliding resistance of the roller end surface with respect to the cage increases, and the rotational resistance of the rotational support portion incorporating the thrust cylindrical roller bearing 1 increases. Not only is the performance deteriorated, but it may cause a failure such as flaking or seizure if it is remarkable. Wear that causes such inconvenience is more likely to occur than in the past, as the speed of rotation of various mechanical devices such as transmissions and car air conditioner compressors has increased due to recent improvements in automobile performance. ing.

JP-A-6-94038 JP 2000-213546 A JP 2002-206525 A JP-A-11-351245 JP 2003-83333 A

  The present invention has been invented to realize a structure capable of suppressing wear of the outer peripheral side peripheral portion of the pocket provided in the cage in view of the above-described circumstances.

The thrust cylindrical roller bearing of the present invention includes a cage and a plurality of cylindrical rollers, similarly to the previously known thrust cylindrical roller bearing.
Of these, the cage is formed in an annular shape as a whole, and includes a plurality of pockets arranged in a radial direction at a plurality of locations in the circumferential direction.
Further, each of the cylindrical rollers is rotatably held in each pocket of the cage.
In particular, in the thrust cylindrical roller bearing according to the present invention, each of these cylindrical rollers is provided at least on the outer diameter side end face of the cage in the direction perpendicular to the respective rotation center axis among the respective axial end faces. The center flat surface which spreads and the chamfering part which continues the outer periphery and rolling surface of this center flat surface over the perimeter are provided.
Further, the cage is made of chromium molybdenum steel, and a sulfur nitride layer is formed on the surface, and the hardness of the surface is set to Hv 600 or more. Further, the axial displacement is caused by the engagement between the rolling surface of each cylindrical roller and any one of the peripheral portions of each pocket, and both the axial side surfaces of the cage and the mating race surface come into contact with each other. It is a thing (roller guide) that is restricted to the state that does not.
Further, the cage is displaced toward one end in the axial direction, and the rolling surface of each cylindrical roller is engaged with the portion near the other end in the axial direction of the peripheral edge of each pocket. The amount of the cylindrical roller protruding from the side surface on the other end side in the axial direction of the cage (roller protruding amount) is set to be less than the width dimension of the chamfered portion in the radial direction of each cylindrical roller.
At the same time, the cage is displaced to the other end side in the axial direction, and the rolling surface of each cylindrical roller is engaged with the peripheral portion of each pocket near the one end in the axial direction. The difference between the amount that each cylindrical roller protrudes from the side surface on the other axial end side of the cage (negative roller drop amount) and the width dimension of the chamfered portion in the radial direction of each cylindrical roller, It is made smaller than the plate | board thickness of the part which comprises the side surface of the said other end side among the said holder | retainers.

  According to the present invention configured as described above, wear on the outer peripheral side edge of each pocket provided in the cage is suppressed, and the outer diameter side end of each cylindrical roller based on this wear is outside the retainer. A thrust cylindrical roller bearing can be obtained that can be prevented from entering one side of the near-diameter portion. That is, in the case of the present invention, since the surface hardness of the cage is Hv 600 or more, the wear resistance of the cage can be improved and the wear of the outer peripheral side edge portion can be suppressed. In addition, even if the SPCC material conventionally used as the material of the cage is subjected to nitrosulphurizing treatment, the surface hardness can be increased only to about Hv 540, but the chromium molybdenum which is the material of the cage of the present invention. When steel is subjected to nitronitriding, the surface hardness can be increased to Hv 600 or more.

  In the case of the present invention, since the oxynitride layer is formed on the surface of the cage, the frictional resistance of this surface can be reduced. For this reason, the frictional resistance of the outer peripheral edge portion can be reduced, and the wear resistance and seizure resistance of the outer peripheral edge portion can be improved. That is, the sulfur nitride layer is composed of a sulfur-containing sulfur layer, a nitrided compound layer, and a diffusion layer in which nitrogen is diffused in order from the outermost surface side. Of these, the sulfur component of the sulfurized layer formed on the outermost surface is excellent in lubricity and functions like a solid lubricant. For this reason, the frictional resistance of the surface of the cage can be reduced, and the wear resistance and seizure resistance of the outer peripheral edge can be improved. In addition, since the surface of a preform | base_material is cleaned when forming a oxynitride layer, a high quality nitrosulfide layer is easy to be formed. Furthermore, due to the presence of the oxynitride layer, the frictional heat generated at the rubbed portion between the outer peripheral side edge portion and the outer diameter side end surface of each cylindrical roller is suppressed, and the adhesion phenomenon is less likely to occur at the rubbed portion. Thus, wear can be suppressed. In addition, a salt bath process, a gas process, etc. are mentioned as a process (nitronitridation process) method of forming a sulfur nitride layer on the surface of a cage | basket.

  In addition, the rubbing portion between the outer peripheral side edge portion of each pocket and the outer diameter side end surface of each cylindrical roller held in each pocket is accommodated within a narrow range compared to the conventional case, and this rubbing portion. Can be positioned more in the circumferentially central portion of each pocket. For this reason, the local stress concentration generated in the rubbing portion due to the one piece contact due to the skew can be alleviated, and the sliding speed V of the rubbing portion can be further reduced. As a result, the recessed portion 23 due to wear as shown in FIG. 9 can be hardly formed on the outer peripheral side peripheral edge portion. As a result, it is possible to prevent the cylindrical rollers from entering a portion near the outer diameter of the cage.

Further, since the difference between the negative roller drop amount and the width of the chamfered portion in the radial direction is made smaller than the thickness of the metal plate constituting the cage, the chamfered portion is outside the pocket. By contacting the radial peripheral edge, adverse effects on the smooth rotation of each cylindrical roller can be prevented, and durability can be improved.
Further, since the axial position of the cage is achieved by the engagement between the peripheral edge of each pocket and the rolling surface of each cylindrical roller, both the axial side surfaces of the cage and the mating race surface are There is no rubbing. For this reason, it is possible to prevent the retainer from scraping off the lubricating oil adhering to the race surface and to satisfactorily lubricate the rolling contact portion between the race surface and the rolling surface of each cylindrical roller.

In carrying out the present invention, for example, as described in claim 2, the cage is made of 0.13-0.18 wt% carbon, 0.15-0.35 wt% silicon, .Chromium molybdenum steel containing 9 to 1.2 wt% chromium, 0.05 to 0.1 wt% aluminum, and 0.15 to 0.3 wt% molybdenum (added aluminum to JIS SCM415) Made).
If such a material is used, the surface hardness of the cage can be sufficiently increased, and the effect of preventing wear on the inner periphery of the pocket can be sufficiently enhanced.

Further, for example, as described in claim 3, a cage that is integrally formed by bending a metal plate is used.
The retainer includes an inner diameter side rim portion, an outer diameter side rim portion, an intermediate plate portion, a plurality of pockets, and a plurality of pillar portions.
Of these, the inner diameter side rim portion is present at the inner peripheral edge and has an annular shape continuous over the entire circumference, and the outer diameter side rim portion is present at the outer peripheral edge portion and is concentric with the inner diameter side rim portion. It is an annular shape that continues around the entire circumference.
Further, the intermediate plate portion exists between the outer diameter side rim portion and the inner diameter side rim portion, and the cross-sectional shape is bent in the radial direction, and the central flat plate portion, the outer diameter side flat plate portion, The inner diameter side flat plate portion, the inner diameter side continuous portion, and the outer diameter side continuous portion.
Among these, the central flat plate portion is formed at a portion near one end in the axial direction at the radial intermediate portion.
Further, the outer diameter side flat plate portion is formed in a portion near the other end in the axial direction adjacent to the radially inner side of the outer diameter side rim portion.
Further, the inner diameter side flat plate portion is formed in a portion near the other end in the axial direction adjacent to the radially outer side of the inner diameter side rim portion.
The inner diameter side continuous portion continuously connects the outer peripheral edge of the inner diameter side flat plate portion and the inner peripheral edge of the central flat plate portion, and the outer diameter side continuous portion includes the outer peripheral edge of the central flat plate portion and the outer diameter side. The inner peripheral edge of the flat plate portion is made continuous.
The pockets are rectangular holes that are long in the radial direction of the intermediate plate portion, and are formed in the intermediate plate portion in the radial direction intermittently in the circumferential direction.
Moreover, each said pillar part is provided between the pockets adjacent to the circumferential direction.

  Alternatively, as described in claim 4, a pair of cage elements each having an annular portion in which a plurality of through holes for forming each pocket are formed in the circumferential direction are used as the cage. , Used in the axial direction.

  Further, when implementing each of the above-described inventions, preferably, as described in claim 5, the cage is displaced toward one end in the axial direction, and the rolling surface of each cylindrical roller and the peripheral portion of each pocket The amount of a part of each cylindrical roller protruding from the side surface on the other end side in the axial direction of the cage, and the other end side in the axial direction, with the portion closer to the other end in the axial direction of In a state where the rolling surfaces of the respective cylindrical rollers are engaged with the portions near the one end in the axial direction of the peripheral portions of the respective pockets, a part of each of the cylindrical rollers is moved to the shaft of the cage. The difference from the amount protruding from the side surface at the other end in the direction, that is, the backlash amount in the axial direction of the cage with respect to each cylindrical roller is set to 50 μm or more.

  While satisfying the above-mentioned conditions for positioning the cage in the axial direction with roller guides, if the play is secured to 50 μm or more, the rolling surfaces of the cylindrical rollers and the pockets constituting the cage It is possible to sufficiently secure a gap between the peripheral edges of the circumferential edges of the circumferential edges. For this reason, it is possible to prevent the lubricating oil adhering to the rolling surface of each cylindrical roller from being scraped off by the circumferential side edges of each pocket, and to prevent the rolling surface of each cylindrical roller from mating with the race surface. Sufficient lubricating oil can be supplied to the rolling contact portion. And sufficient oil film can be formed in each of these rolling contact portions, and the rolling fatigue life of the rolling surface and the mating race surface of each cylindrical roller can be ensured.

More preferably, as described in claim 6, the surface roughness of the central flat surface of each cylindrical roller is 0.31 μm or less in terms of arithmetic average roughness, and the outer peripheral side peripheral portion of each pocket is The surface roughness is 2.54 μm or less in terms of arithmetic average roughness.
If comprised in this way, it will become easy to form an oil film in the contact part of the center flat surface of each cylindrical roller and the outer peripheral side peripheral part of each pocket, and the amount of wear of these each contact part can be reduced. As a result, the cylindrical rollers can be more effectively prevented from entering the cage.

  1 and 2 show an embodiment of the present invention corresponding to claims 1 to 3, 5 and 6. The feature of the present invention is that the outer peripheral side peripheral portion 22 of each pocket 7 is subjected to nitronitridation on the surface of the cage 2a in order to make it less likely to cause wear that leads to the recessed portion 23 shown in FIG. A layer is formed, the surface hardness is set to Hv 600 or more, and the pockets 7 are defined in relation to the width dimension in the radial direction of the chamfered portion 11 formed on the outer diameter portion of each cylindrical roller 8, 8. This is to restrict the movement of the cylindrical rollers 8 and 8 inside. Since the basic configuration and operation of the thrust cylindrical roller bearing 1a are the same as those of the conventional structure shown in FIGS. 4 to 8, the overlapping illustrations and explanations are omitted or simplified. The explanation will be focused on.

  In the case of the present embodiment, the cage 2a is made by using 0.13 to 0.18% by weight of carbon (C), 0.15 to 0.35% by weight of silicon (Si), and 0.9 to 1.%. Chromium molybdenum steel (JIS SCM415) containing 2 wt% chromium (Cr), 0.05 to 0.1 wt% aluminum (Al), and 0.15 to 0.3 wt% molybdenum (Mo) To which aluminum is added). In the case of the present embodiment, a sulfur nitride layer is formed on the entire surface of the cage 2a, and the surface hardness of the cage 2a is set to Hv 600 or more.

  That is, the metal plate having the composition as described above is subjected to predetermined punching and bending processes to form a cage 2a having a shape as shown in FIGS. Then, nitrosulphurizing treatment is performed to simultaneously infiltrate and diffuse nitrogen and sulfur on the surface of the base material. As a result, a sulfur nitride layer is formed on the entire surface of the cage 2a. This sulfur nitrided layer is composed of a sulfur-containing sulfurized layer, a nitrided compound layer, and a diffusion layer in which nitrogen is diffused in order from the outermost surface side. Further, by forming the oxynitride layer in this way, the hardness of the surface of the cage 2a is set to Hv 600 or more over the entire surface. Accordingly, a sulfur nitride layer is also formed on the surface of the outer peripheral side peripheral portion 22 of each pocket 7, and the surface hardness of the outer peripheral side peripheral portion 22 is Hv600 or more.

In the case of the present embodiment, as shown in FIG. 2A, the cage 2a is displaced toward one end side in the axial direction (lower side in FIGS. In a state where the outer diameter side locking portions 18, 18 and the inner diameter side locking portions 19, 19 are engaged with the rolling surfaces 10 of the cylindrical rollers 8, a part of the cylindrical rollers 8 is held by the above. The amount of protrusion (roller protrusion amount) δ ₁ protruding from the outer surface of both the outer diameter side and inner diameter side flat plate portions 14 and 15 constituting the vessel 2a is less than the width dimension W of the chamfered portion 11 in the radial direction of each cylindrical roller 8 ( δ ₁ <W). Accordingly, in a state where the outer diameter side and inner diameter side locking portions 18 and 19 are engaged with the rolling surfaces 10 of the cylindrical rollers 8, as shown by a diagonal lattice in FIG. The friction surface between the central flat surface 9 of each cylindrical roller 8 and the outer peripheral side peripheral edge portion 22 (FIG. 1) of each pocket 7 falls within the thickness range of the metal plate constituting the cage 2a. . In other words, the chamfered portion 11 is opposed to a portion near the surface of the outer diameter side flat plate portion 14 away from the rotation axis of each cylindrical roller 8 in the outer diameter side peripheral edge portion 22 of each pocket 7. A gap exists between these portions close to the surface and the chamfered portion 11 (no rubbing).

In the case of this embodiment, as shown in FIG. 2B, the cage 2a is displaced to the other end side in the axial direction (the upper side in FIGS. In a state where the central locking portions 20 and 20 are engaged with the rolling surfaces 10 of the cylindrical rollers 8, a part of each of the cylindrical rollers 8 is fixed to the outer diameter side and inner diameter side flat plate portions 14, 15 is projected from the outer surface by δ ₂ minutes (negative roller drop amount). Then, the difference (W−δ ₂ ) between the protrusion amount δ ₂ and the width dimension W of the chamfered portion 11 in the radial direction of each cylindrical roller 8 is determined from the thickness T of the metal plate constituting the cage 2a. Is also small {(W−δ ₂ ) <T}. Therefore, even when the central locking portions 20 and 20 and the rolling surfaces 10 of the cylindrical rollers 8 are engaged with each other, the cylindrical rollers 8 as shown in FIG. The central flat surface 9 and the outer diameter side peripheral edge 22 of each pocket 7 rub against each other. In other words, the inner surface side edge of the outer diameter side peripheral edge portion 22 and the chamfered portion 11 do not rub against each other (contact with the edge).

In the case of this embodiment, the backlash amount in the axial direction of the cage 2a with respect to each cylindrical roller 8 is set to 50 μm or more. That is, the cage 2a is displaced toward one end in the axial direction, and the outer diameter side engaging portions 18 and 18 and the inner diameter side engagements constituting the rolling surfaces 10 of the cylindrical rollers 8 and the pockets 7 are provided. In a state where the stoppers 19 and 19 are engaged, a part of each cylindrical roller 8 protrudes from the outer surface of both the outer diameter side and inner diameter side flat plate parts 14 and 15 (that is, δ ₁ ), In a state where the cage 2a is displaced to the other end side in the axial direction and the rolling surfaces 10 of the cylindrical rollers 8 and the central flat plate portions 20 and 20 constituting the pockets 7 are engaged, The difference (δ ₁ −δ ₂ ) from the amount of each cylindrical roller 8 protruding from the outer surfaces of the outer diameter side and inner diameter side flat plate portions 14 and 15 (that is, δ ₂ ) is 50 μm or more. Yes.

  Furthermore, in this embodiment, the surface roughness of the central flat surface 9 of each cylindrical roller 8 is 0.31 μm or less (preferably 0.3 μm or less) in terms of arithmetic average roughness (Ra), and each pocket 7 The surface roughness of the outer diameter side peripheral edge 22 is 2.54 μm or less (preferably 2.5 μm or less) in terms of arithmetic average roughness (Ra).

  In the case of the present embodiment, the outer diameter side rim portion 5 a is composed of a cylindrical portion 24 that is continuous with the intermediate plate portion 6, and a folded portion 25 that is folded 180 ° from the tip end portion of the cylindrical portion 24. The tip of the folded portion 25 does not protrude from the outer surfaces of the outer diameter side and inner diameter side flat plate portions 14 and 15. In the case of the cage 2a of the present embodiment, the folded portion 25 is formed on the outer diameter side rim portion 5a as described above, but this folded portion 25 is formed like the conventional structure shown in FIGS. May not be formed. However, even if the force acting on the outer diameter side rim portion 5a is increased by the centrifugal force acting on each cylindrical roller 8 during operation by forming the folded portion 25, the outer diameter side rim portion 5a is Easy to ensure strength.

  According to the present embodiment configured as described above, the wear of the outer diameter side peripheral edge 22 of each pocket 7 provided in the cage 2a is suppressed, and the outer diameter side end of each cylindrical roller 8 based on this wear is reduced. The thrust cylindrical roller bearing 1a can be obtained which can prevent the cage 2a from entering one side of the portion near the outer diameter. That is, in the case of the present embodiment, since the surface hardness of the cage 2a is set to Hv 600 or more, the wear resistance of the cage 2a can be improved and the wear of the outer peripheral side peripheral portion 22 can be suppressed.

  In the case of this embodiment, since the oxynitride layer is formed on the entire surface of the cage 2a, the frictional resistance (friction coefficient) of this surface can be reduced. For this reason, the frictional resistance of the outer peripheral edge portion 22 can be reduced, and the wear resistance and seizure resistance of the outer peripheral edge portion 22 can be improved. That is, the sulfur component of the sulfurized layer formed on the outermost surface of the sulfur nitrided layer is excellent in lubricity and functions like a solid lubricant. The frictional resistance of the outer peripheral side peripheral edge 22 can be reduced, and the wear resistance and seizure resistance can be improved. Further, due to the presence of the oxynitride layer, the frictional heat generated at the rubbing portion between the outer diameter side peripheral edge portion 22 and the outer diameter side end surface 21 of each cylindrical roller 8 is suppressed, and adhesion occurs at the rubbing portion. The phenomenon is less likely to occur and wear can be suppressed.

  Further, in the case of the present embodiment, of the outer diameter side peripheral edge portion 22, the outer surface of the outer diameter side flat plate portion 14 away from the center axis of rotation of each cylindrical roller 8 {the upper surface of FIG. And the central flat surface 9 of each cylindrical roller 8 is prevented from rubbing. In other words, the rubbing portion between the outer peripheral side peripheral portion 22 of each pocket 7 and the central flat surface 9 of each cylindrical roller 8 held in each pocket 7 is shown in FIG. As indicated by the lattice, the pockets 7 are located at the central portions in the circumferential direction. For this reason, the local stress concentration generated in the rubbing portion due to the piece contact due to the skew can be alleviated, and the sliding speed V of the rubbing portion can be kept small. As a result, the recessed portion 23 due to wear as shown in FIG. 9 can be hardly formed in the outer peripheral side peripheral edge portion 22 portion. Further, the inner edge of the outer peripheral edge 22 and the chamfered portion 11 do not come into contact with each other, and no significant wear occurs in the portion.

In this embodiment, the difference between the negative roller drop amount δ ₂ and the width dimension W in the radial direction of the chamfered portion 11 is made smaller than the thickness T of the metal plate constituting the cage 2a. Therefore, the chamfered portion 11 can be prevented from adversely affecting the smooth rotation of each cylindrical roller 8 by contacting (per edge) with the outer peripheral side peripheral edge portion 22 of each pocket 7, and durability can be improved. Improvements can be made.

  In the case of this embodiment, the axial position of the cage 2 a is related to the locking portions 18 to 20 formed in the pockets 7 and the rolling surfaces 10 of the cylindrical rollers 8. Therefore, the both side surfaces in the axial direction of the cage 2a are not rubbed against the mating race surface. For this reason, the cage 2a is prevented from scraping off the lubricating oil adhering to the race surface, and the rolling contact portion between the race surface and the rolling surface 10 of each cylindrical roller 8 can be well lubricated. For this reason, it is possible to prevent damage to the rolling surface 10 and the respective race surfaces even under severe use conditions.

  Further, as long as the play amount is secured to 50 μm or more while satisfying the conditions for positioning the cage 2a in the axial direction with the roller guide as described above, the rolling surfaces 10 of the cylindrical rollers 8 and the holding are retained. A sufficient gap can be secured between the peripheral edges of each pocket 7 constituting the container 2a and both side edges in the circumferential direction. For this reason, the lubricating oil adhering to the rolling surface 10 of each cylindrical roller 8 is prevented from being scraped off by the circumferential side edges of each pocket, and the rolling surface 10 of each cylindrical roller 8 and the counterpart Sufficient lubricating oil can be supplied to the rolling contact portion with the race surface. And sufficient oil film can be formed in each of these rolling contact parts, and the rolling fatigue life of the rolling surface 10 of each said cylindrical roller 8 and the other race surface can be ensured.

  In the case of the present embodiment, the surface roughness of the central flat surface 9 of each cylindrical roller 8 is set to 0.31 μm or less (preferably 0.3 μm or less) in Ra, and the outer peripheral side peripheral portion of each pocket 7. 22 has a surface roughness Ra of 2.54 m or less (preferably 2.5 μm or less), so that the contact between the central flat surface 9 of each cylindrical roller 8 and the outer peripheral edge 22 of each pocket 7 is as follows. It is easy to form an oil film on the part, and the wear amount of each contact part can be reduced. As a result, the cylindrical rollers 8 can be more effectively prevented from entering the cage 2a.

The following Tables 1 to 3 show the results of experiments conducted to confirm the effects of this example. In each of these experiments, after running for 63 hours at a relative rotational speed of 11000 min ⁻¹ of a pair of races that constitute a thrust cylindrical roller bearing and rotate relative to each other in an unloaded state (axial load is almost 0), the cage The wear depth (mm) of the outer-diameter side peripheral edge portion of the outer diameter-side peripheral edge portion of each of the pockets was worn. ATF was used as the lubricating oil. The oil temperature was 130 ° C. In addition, the shape of each cage used in the experiment was the same as that of the above-described embodiment, and the size used was a pitch circle diameter (PCD) of 48 mm. Further, the cylindrical rollers used have the same shape as the cage of the above-described embodiment and all have the same size.

  First, Tables 1 and 2 show the specifications of the cage incorporated in the thrust cylindrical roller bearing used in this experiment for the experiment conducted to examine the influence of the cage material and surface treatment on the wear of the cage. The results of this experiment are shown respectively. Of these, Table 1 shows the specifications of each cage. In the experiment, four types of cages were used. Of these, the cage (1) is a cold rolled steel plate (SPCC) cage subjected to a salt bath treatment at a treatment temperature of 570 ° C., and the surface of the cage is infiltrated with nitrogen to increase the surface hardness. Hv508. The cage (2) is a cold-rolled steel plate (SPCC) cage subjected to a salt bath treatment in which a sulfur compound is mixed at a treatment temperature of 560 ° C., and a oxynitride layer is formed on the surface of the cage. The surface hardness is set to Hv543. The cage (3) is made of 0.14% by weight of carbon (C), 0.95% by weight of chromium (Cr), 0.24% by weight of silicon (Si), 0.08% by weight of aluminum ( Al), a cage made of chromium molybdenum steel containing 0.26% by weight of molybdenum (Mo) is subjected to a salt bath treatment in which a sulfur compound is mixed at a treatment temperature of 560 ° C., and the surface of the cage is sulfurized. A nitride layer is formed and the surface hardness is Hv621. The retainer (4) is a chrome molybdenum steel retainer having the same composition as the retainer (3). The retainer (4) forms a sulfur nitrided layer on the surface of the retainer, and has a surface hardness. Is Hv613.

Further, in the case of the thrust cylindrical roller bearing incorporating the cages (1) to (3), the roller protrusion amount δ ₁ is less than the width dimension W in the radial direction of the chamfered portion of the cylindrical roller (δ ₁ <W ) {See (A) of FIG. 2} and the difference between the roller drop amount δ ₂ and the width dimension W in the radial direction of the chamfered portion is smaller than the plate thickness T of the cage {(W−δ ₂ ) <T, see FIG. 2B}. On the other hand, for the thrust cylindrical roller bearing incorporating the cage (4), the roller protrusion amount δ ₁ is larger than the width dimension W in the radial direction of the chamfered portion of the cylindrical roller (δ ₁ > W ) And the difference between the roller drop amount δ ₂ and the width dimension W in the radial direction of the chamfered portion is larger than the plate thickness T of the cage {(W−δ ₂ )> T}.

Table 2 shows the results of experiments conducted on the above-described conditions for the thrust cylindrical roller bearings incorporating the cages (1) to (4) described above.

  As apparent from Table 2, among the cages (1) to (4), the thrust cylindrical roller bearing incorporating the cage (3) belonging to the technical scope of the present invention is provided outside the pocket. It can be seen that the wear on the diameter side periphery can be reduced most. That is, when the cage (1) and the cage (2) are compared, it can be seen that the wear can be further reduced by forming the oxynitride layer on the surface. In addition, when the cage (2) and the cage (3) are compared, it can be seen that the wear can be further reduced by forming a sulfur nitride layer on the surface and changing the material to a surface hardness of 600 or more. . However, unless the relationship between the amount of roller protrusion and the width dimension of the chamfered portion and the difference between the roller drop amount and the width dimension of the chamfered portion and the cage plate thickness are not properly regulated, the cage ( As can be seen from the results of the experiment using 4), the increase in wear cannot be sufficiently suppressed.

  Next, Table 3 shows the experimental results of examining the influence of the surface roughness of the central flat surface of the cylindrical roller and the surface roughness of the outer diameter side peripheral edge portion on the wear of the outer diameter side peripheral edge portion of each pocket. For each cylindrical roller, three types of surface roughness Ra, 0.48 μm, 0.31 μm, and 0.22 μm are prepared for the central flat surface of the outer diameter side end surface, and the outer diameter side is used as a cage. The surface roughness of the peripheral edge was Ra, and three types of 3.42 μm, 2.54 μm, and 1.77 μm were prepared and combined. Each cage used in the experiment has the same specifications as the cage (3) used in the experiments in Tables 1 and 2 described above.

  As is apparent from Table 3, the wear depth of the outer peripheral edge portion shows good results in the entire range. In particular, the surface roughness of the central flat surface of the cylindrical roller is 0. In the range of 31 μm or less and the surface roughness of the peripheral portion on the outer diameter side being 2.54 μm or less, better results are shown. Therefore, if the various conditions of the present embodiment are satisfied and the surface roughness of the central flat surface and the outer peripheral edge is restricted, the wear of the outer peripheral edge can be sufficiently suppressed. It can be seen that the rollers can be more effectively prevented from entering the inside of the cage.

  Although the embodiment described above is shown when the present invention is applied to the thrust cylindrical roller bearing 1a in which the cage 2a formed by bending one metal plate is incorporated, the present invention claims The present invention can also be applied to a structure as described in item 4. That is, as shown in FIG. 3, each of the cages 2b has annular portions 27a and 27b in which through holes 26a and 26b for forming the pockets 7 and 7 are formed at a plurality of locations in the circumferential direction. The present invention can also be applied to a thrust cylindrical roller bearing 1b using a pair of cage elements 28a and 28b that are overlapped in the axial direction.

  More specifically, 0.13-0.18 wt% carbon (C), 0.15-0.35 wt% silicon (Si), 0.9-1.2 wt% chromium ( Cr), chromium-molybdenum steel containing 0.05 to 0.1 wt% aluminum (Al) and 0.15 to 0.3 wt% molybdenum (Mo) (aluminum added to JIS SCM415) The metal plate is subjected to predetermined punching and bending processes to form both the cage elements 28a and 28b, and then subjected to nitronitriding treatment, and the surface hardness of both the cage elements 28a and 28b is set to Hv600. In addition to the above, a sulfur nitride layer is formed on the entire surface of both the cage elements 28a and 28b. The cage elements 28a and 28b are overlapped with each other to form the cage 2b. Even if comprised in this way, the wear resistance and seizure resistance of the cage 2b can be improved, and the frictional resistance can be reduced to reduce the outer peripheral side peripheral edge portion 22a of each of the pockets 7, 7. The wear of 22b can be suppressed.

The thrust cylindrical roller bearing 1b has a relationship between the roller protrusion amount and the width dimension of the chamfered portion 11 of each cylindrical roller 8 and 8, and the negative roller drop amount and the radial direction of the chamfered portion 11. The relationship between the difference from the width dimension and the plate thickness of the annular portions 27a and 27b of the cage elements 28a and 28b is regulated as follows.
First, the cage 2b is displaced in the axial direction by the engagement between the rolling surfaces 10 of the cylindrical rollers 8 and 8 and the peripheral portions of the through holes 26a and 26b constituting the pockets 7 and 7, respectively. The cage 2b is restricted so that the both side surfaces in the axial direction do not come into contact with the mating race surface.
Further, the cage 2b is displaced, for example, to one end side in the axial direction (the lower side in FIG. 3) to constitute the rolling surfaces 10 of the cylindrical rollers 8 and 8 and the pockets 7 and 7, respectively. In a state where the peripheral edge of the through hole 26b of the cage element 28b existing near the other end (upper side in FIG. 3) is engaged, a part of each of the cylindrical rollers 8, 8 is in the axial direction of the cage 2b. The amount protruding from the outer surface (upper surface in FIG. 3) of the circular ring portion 27b, which is the side surface on the other end side, is less than the width dimension of the chamfered portion 11 in the radial direction of the cylindrical rollers 8 and 8. To do.
At the same time, the cage 2b is displaced to the other axial end side to constitute the rolling surfaces 10 of the cylindrical rollers 8 and 8 and the pockets 7 and 7, respectively. In a state in which the peripheral edge portion of the through hole 26a of the element 28a is engaged, the amount that each of the cylindrical rollers 8 and 8 protrudes from the outer surface of the annular portion 27b (negative roller drop amount), and these A difference from the width dimension of the chamfered portion 11 in the radial direction of each cylindrical roller 8, 8 is made smaller than the plate thickness of the annular ring portion 27b.
Even if the relationship between the one end side and the other end side in the axial direction is reversed, the relationship between the amount of roller protrusion and the width dimension in the radial direction of the chamfered portion of each cylindrical roller 8, 8 and the negative roller drop Of course, the relationship between the difference between the amount and the width of the chamfered portion in the radial direction and the plate thickness of the annular portions 27a and 27b of the cage elements 28a and 28b is regulated as described above.

Sectional drawing which shows the Example of this invention. In order to explain the embodiment of the present invention, (A) shows a state in which the cage is displaced to one end side in the axial direction with respect to the cylindrical roller, and (B) shows the other end side in the axial direction with respect to the cylindrical roller. FIG. 2 is a diagram corresponding to the E1 cross section of FIG. Sectional drawing which shows another structure which can apply this invention. Sectional drawing which shows an example of a conventional structure. The side view which takes out and shows a cylindrical roller. A thrust cylindrical roller bearing showing a state in which the cage is displaced to one end side in the axial direction shown in (A) and the other end side in the axial direction shown in (B) with respect to the cylindrical roller includes the central axis of the cage. The fragmentary sectional view shown in the state cut | disconnected by the virtual plane. The figure which shows this pocket in the state seen from the central-axis direction of the holder | retainer in order to show the shape of the pocket of a holder | retainer. Sectional drawing similar to FIG. 2 for demonstrating the inconvenience which arises when the dimension of the chamfering part of the axial direction end surface of a cylindrical roller is improper. The figure similar to FIG. 7 which shows the state which the outer peripheral side peripheral part of the pocket of the holder | retainer was worn out.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b Thrust cylindrical roller bearing 2, 2a, 2b Cage 4 Inner diameter side rim part 5, 5a Outer diameter side rim part 6 Intermediate plate part 7 Pocket 8 Cylindrical roller 9 Central flat surface 10 Rolling surface 11 Chamfered part 12 Column portion 13 Central flat plate portion 14 Outer diameter side flat plate portion 15 Inner diameter side flat plate portion 16 Inner diameter side continuous portion 17 Outer diameter side continuous portion 18 Outer diameter side locking portion 19 Inner diameter side locking portion 20 Central locking portion 21 Outer diameter side End surface 22, 22a, 22b Outer diameter side peripheral edge 23 Recessed portion 24 Cylindrical portion 25 Folded portion 26a, 26b Through hole 27a, 27b Ring portion 28a, 28b Cage element

Claims (6)

  A cage that is formed in an annular shape and is provided with a plurality of pockets that are radially arranged at a plurality of locations in the circumferential direction, and a plurality of cylindrical rollers that are rotatably held in the pockets. Each of these cylindrical rollers has a central portion that extends in a direction perpendicular to the respective rotation center axis at least on the outer diameter side end surface of the cage among the axial end surfaces of the cylindrical roller bearings. The cage is provided with a flat surface and a chamfered portion for continuously connecting the outer peripheral edge of the central flat surface and the rolling surface over the entire circumference. The cage is made of chrome molybdenum steel, and is immersed in the surface. A sulfuration nitride layer is formed, and the hardness of this surface is set to Hv 600 or more, and the axial displacement is caused by the engagement between the rolling surface of each cylindrical roller and the peripheral portion of each pocket, Both sides of the cage in the axial direction The surface is regulated so as not to contact the surface, and the cage is displaced toward one end in the axial direction, so that the rolling surface of each cylindrical roller and the axial direction of the peripheral portions of the pockets, etc. The amount of a part of each cylindrical roller protruding from the side surface on the other end side in the axial direction of the cage in the state where the end portion is engaged is the width of the chamfered portion in the radial direction of each cylindrical roller. The size is less than the dimension, the cage is displaced to the other axial end, and the rolling surface of each cylindrical roller is engaged with the axially one end portion of the peripheral edge of each pocket. Thus, the difference between the amount of a part of each cylindrical roller protruding from the side surface on the other end side in the axial direction of the cage and the width dimension of the chamfered portion in the radial direction of each cylindrical roller is expressed as follows. Of these, the thickness of the portion constituting the side surface on the other end side is smaller than the thickness. Thrust cylindrical roller bearing.   The cage includes 0.13-0.18 wt% carbon, 0.15-0.35 wt% silicon, 0.9-1.2 wt% chromium, 0.05-0.1 The thrust cylindrical roller bearing according to claim 1, wherein the thrust cylindrical roller bearing is made of chromium molybdenum steel containing aluminum by weight and 0.15-0.3% by weight molybdenum.   A cage is integrally formed by bending a metal plate, and is present on the inner peripheral edge, and is present on the inner peripheral rim that is continuous over the entire circumference, and on the outer peripheral edge. An annular outer rim portion that is concentric with the inner rim portion and continuous over the entire circumference, and a cross-sectional shape that exists between the outer rim portion and the inner rim portion is in the radial direction. A bent intermediate plate portion, a plurality of pockets formed radially in the intermediate plate portion intermittently in the circumferential direction, and a plurality of column portions provided between pockets adjacent in the circumferential direction. The intermediate plate portion is formed in a central flat plate portion formed near the one end in the axial direction at the radially intermediate portion and a portion near the other end in the axial direction adjacent to the radially inner side of the outer rim side rim portion. The outer diameter side flat plate portion and the axially other end portion adjacent to the radially outer side of the inner diameter side rim portion. An inner diameter side flat plate portion, an inner diameter side continuous portion connecting the outer peripheral edge of the inner diameter side flat plate portion and the inner peripheral edge of the central flat plate portion, and the outer peripheral edge of the central flat plate portion and the outer diameter side flat plate portion. The thrust cylindrical roller bearing according to claim 1 or 2, comprising an outer diameter side continuous portion that makes the inner peripheral edge of the outer peripheral side continuous.   Each of the cages is formed by superimposing a pair of cage elements each having an annular portion in which a plurality of through holes for forming each pocket are formed in the circumferential direction in an axial direction. A thrust cylindrical roller bearing according to claim 1 or 2.   Displace the cage toward one end in the axial direction, and engage a part of each cylindrical roller with the rolling surface of each cylindrical roller and the peripheral portion of each pocket near the other end in the axial direction. Is an amount protruding from the side surface on the other end side in the axial direction of the cage, and the cage is displaced to the other end side in the axial direction, of the rolling surface of each cylindrical roller and the peripheral portion of each pocket. The state in which a part of each of the cylindrical rollers protrudes from the side surface on the other end side in the axial direction of the cage in a state in which the portion near one end in the axial direction is engaged is set to 50 μm or more. 4. A thrust cylindrical roller bearing according to any one of 4.   The surface roughness of the central flat surface of each cylindrical roller is 0.31 μm or less in arithmetic mean roughness, and the surface roughness of the outer diameter side peripheral portion of each pocket is 2.54 μm or less in arithmetic mean roughness. A thrust cylindrical roller bearing according to any one of claims 1 to 5.

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