JP6501504B2 - Thrust roller bearing cage and method of manufacturing the same - Google Patents

Description

  The present invention relates to a thrust roller bearing cage (hereinafter sometimes simply referred to as "cage") and a method of manufacturing the same, and in particular, a thrust roller bearing cage manufactured using a press, and It relates to the manufacturing method.

  For example, a thrust roller bearing that receives a thrust load may be disposed at a position to which the thrust load is applied in an automatic transmission for a car, a compressor for a car air conditioner, or the like. With respect to such thrust roller bearings, it is desirable to reduce the rotational torque of the bearings from the viewpoint of reducing fuel consumption and labor. The thrust roller bearing includes a bearing ring disposed in the rotational axis direction, a plurality of needle rollers rolling on a bearing surface of the bearing ring, and a cage for holding the plurality of needle rollers. The cage may be manufactured by folding a steel plate and then removing a pocket for housing a roller.

  The technique regarding the holder | retainer with which such a thrust roller bearing is equipped is disclosed by Unexamined-Japanese-Patent No. 10-220482 (patent document 1), for example. The thrust roller bearing retainer disclosed in Patent Document 1 includes an annular main body that is punched out or punched out, and a convex portion provided on the outer diameter side of the annular main body, and the convex portion is a folded back portion of the annular main body. Portions of the end surface on the outer diameter side located in each pocket are protruded in the inner diameter direction so that the tip end is opposed in the vicinity of the center of the roller. According to this thrust roller bearing retainer, it is disclosed that the rotational torque of the roller can be reduced because the tip end of the convex portion contacts near the rotation center of the roller.

JP 10-220482 A

  However, in the thrust roller bearing of Patent Document 1, the entire tip end surface of the convex portion is in contact with the roller. In a thrust roller bearing, the centrifugal force acting on the outer diameter side acts on the roller, so the friction of the entire tip surface of the convex portion, which is a contact portion in contact with the roller, is a rotational resistance. For this reason, in the thrust roller bearing of Patent Document 1, since the rotational resistance can not be sufficiently reduced, the rotational torque can not be sufficiently reduced.

  Further, since the centrifugal force due to the roller is applied to the convex portion, it is necessary to withstand the load from the roller and to maintain the shape of the convex portion. For this reason, the thrust roller bearing is required to maintain high durability against radial load.

  An object of the present invention is to provide a cage for a thrust roller bearing capable of reducing rotational torque and maintaining durability against radial load at the time of thrust roller bearing rotation and a method of manufacturing the same.

  The cage of a thrust roller bearing according to the present invention is a cage of a thrust roller bearing provided in a thrust roller bearing and provided with a plurality of pockets for accommodating the rollers, and a region located outside the pockets is An outer diameter area bent portion formed by bending at an inclination angle of less than 45 ° to the inner diameter side and an end surface of a roller housed in the pocket provided at the tip of the outer diameter area bent portion at a position aligned with each of the pockets And a projection projecting radially inward from an outer edge of the pocket so as to be in contact with the pocket.

  A manufacturing method of a thrust roller bearing cage according to the present invention is a manufacturing method of a thrust roller bearing cage provided with a thrust roller bearing and provided with a plurality of pockets for accommodating rollers, and the holding serving as the cage A step of preparing the vessel material, and an outer shape having a portion to be a protrusion projecting radially inward from the outer diameter side edge of the pocket so as to contact the end surface of the roller housed in the pocket relative to the cage material The step of forming the shape, the step of forming the pocket with respect to the cage material, and the region of the cage material located outside the pocket are bent at an inclination angle of less than 45 ° to the outside, And b. Forming a diameter area bent portion.

  According to the cage of thrust roller bearing of the present invention and the manufacturing method thereof, the outer diameter area bent portion is formed by bending the area located on the outer diameter side with respect to the pocket to the inner diameter side at an inclination angle of less than 45 ° Therefore, compared with the case where it is not inclined as in Patent Document 1 (inclination angle is 0 °), the area of the projecting portion provided at the tip of the outer diameter area bent portion is smaller in contact with the roller. When the roller is urged from the axial center toward the outer diameter by the rotational centrifugal force of the roller, the portion in contact with the roller in the projection becomes friction, but in the present invention, the area in contact with the roller in the projection is Because it is small, rotational resistance can be reduced. For this reason, rotational torque can be reduced.

  In addition, since the outer diameter area bent portion is formed by bending the area located on the outer diameter side of the pocket toward the inner diameter side at an inclination angle of less than 45 °, the rotational centrifugal force of the roller is applied to the projecting portion In the case, it is easy to bear the load from the roller and maintain the shape. For this reason, the durability against radial load at the time of thrust roller bearing rotation can be maintained.

  Preferably, in the cage of the thrust roller bearing of the present invention, the inclination angle is 25 ° or more and 35 ° or less.

  Preferably, in the method of manufacturing the cage for a thrust roller bearing according to the present invention, in the step of forming the outer diameter area bent portion, an area located on the outer diameter side of the pocket in the holder material is 25 ° or more toward the inner diameter Bend at an angle of inclination of less than °.

  A portion of the projecting portion in contact with the roller by setting the inclination angle to 25 ° or more and 35 ° or less even if the portion of the projecting portion in contact with the roller wears using the cage of the thrust roller bearing of the present invention The increase in the area of is small. For this reason, even if the thrust roller bearing cage is used for a long time, reduction in rotational torque can be maintained. Further, by setting the inclination angle to 35 ° or less, the durability against radial load when the thrust roller bearing rotates can be more easily maintained. Furthermore, the outer diameter of the cage can be reduced by setting the inclination angle to 25 ° or more.

  Preferably, in the cage of the thrust roller bearing of the present invention, the area of the projecting portion in contact with the end face of the roller is face-pressed.

  Preferably, the method for manufacturing a cage for a thrust roller bearing according to the present invention further includes the step of performing surface pressing on a region of the projecting portion in contact with the end surface of the roller.

  As a result, since the area of the projecting part in contact with the roller end face is face pressed, the oil film is formed by sliding between the roller end face and the area of the projecting part in contact with the roller end face when the bearing rotates. Can be reduced. Then, the lubricity of the contact area is improved, and the aggression of the roller against the so-called protrusion of the cage can be alleviated. Therefore, such thrust roller bearing cage can further reduce the rotational torque of the bearing.

  The above-mentioned "face pressing process" refers to the projecting portion using the outer diameter surface of the mold which acts as a stopper for controlling the amount of falling down in the process of forming the outer diameter area bent portion. By pressing in the radial direction, it means processing that smoothes the surface roughness before and after processing. Specifically, the press shear surface or the fractured surface formed in the step of forming the outer shape can be smoothed by surface pressing until the arithmetic average roughness Ra (JIS B 0601) is about 2 μm or less.

  According to the thrust roller bearing retainer and the method of manufacturing the same of the present invention, the rotational torque can be reduced, and the durability against radial load can be maintained when the thrust roller bearing rotates.

It is a figure showing a part of cage of a thrust roller bearing concerning one embodiment of this invention. It is sectional drawing of the holder | retainer of the thrust roller bearing shown in FIG. It is an expanded sectional view which shows a part of cage | basket of the thrust roller bearing shown in FIG. It is a flowchart which shows the typical process of the manufacturing method of the holder | retainer of the thrust roller bearing concerning one Embodiment of this invention. It is sectional drawing of the holder | retainer raw material after performing an uneven | corrugated shaped formation process. It is an expanded sectional view expanding and showing a part of cage material after performing a pilot hole formation process. It is an expanded sectional view which expands and shows a part of holder material after performing outline shape formation process. It is a figure which shows a part of holder | retainer raw material after performing a pocket formation process. It is an expanded sectional view which expands and shows a part of holder material after performing a pocket formation process. It is an expanded sectional view which expands and shows a part of cage material in the middle stage of an outside diameter field bending process. It is an expanded sectional view which shows the state which performs an outer-diameter area | region bending process. It is an expanded sectional view which shows the state which performs an outer-diameter area | region bending process. It is an expanded sectional view which expands and shows a part of cage material after performing an outside diameter field bending process. It is an expanded sectional view which expands and shows a part of cage material after performing an outside diameter field bending process. It is an expanded sectional view which shows the state which implements an outer diameter area | region bending process. It is an expanded sectional view which shows the state which performs a surface pressing process. It is an expanded sectional view expanding and showing a tip part of an outside diameter field bent part after performing a face press processing process. FIG. 10 is a cross-sectional view showing a part of a thrust roller bearing cage according to another embodiment of the present invention. It is a figure which shows a part of retainer of the thrust roller bearing which concerns on other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described based on the drawings. In the following drawings, the same or corresponding parts have the same reference characters allotted and description thereof will not be repeated.

FIG. 1 is a view showing a part of a cage 11 of a thrust roller bearing according to an embodiment of the present invention. FIG. 1 is a view of the holder 11 as viewed from the rotational axis direction of the holder 11. FIG. 2 is a cross-sectional view of the cage 11 of the thrust roller bearing shown in FIG. FIG. 2 shows the case of cutting at the cross section shown by the line II-II in FIG. Specifically, the right side of FIG. 2 shows a cross section of a portion where a pocket described later is formed, and the left side of FIG. 2 shows a cross section of a portion where a pillar described later is formed. FIG. 3 is an enlarged sectional view showing a part of the cage 11 of the thrust roller bearing shown in FIG. FIG. 3 is an enlarged sectional view of a region indicated by III in FIG. In addition, in FIG. 2 and FIG. 3, the rotation axis 12 of the holder | retainer 11 is shown with the dashed-dotted line. Further, from the viewpoint of easy understanding, in FIG. 3, needle rollers 13 accommodated in pockets 21 described later, and one of a pair of races 14 and 15 disposed on both sides in the rotational axis direction of the cage 11. The department is illustrated. In addition, the paper surface front and back direction in FIG. 1 and the paper surface up-down direction in FIG. 2 and FIG. Further, the direction of the direction or vice versa indicated by the arrow A ₁ in FIG. 1, a circumferential direction. From the viewpoint of easy understanding, the upper side of the sheet in FIGS. 2 and 3 is taken as the upper side in the axial direction. That is, the direction indicated by arrow A ₂ in FIG. 2 and FIG. 3, the upward direction. Moreover, the paper left-right direction in FIG. 2 and FIG. 3 becomes a radial direction. Direction indicated by arrow A ₃ in FIG. 3, the outer diameter direction.

  First, the configuration of a thrust roller bearing cage 11 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. The cage 11 of the thrust roller bearing according to the embodiment of the present invention is disk-shaped, and is provided with a through hole 22 penetrating straight in the thickness direction in the central region thereof. A rotation shaft (not shown) is disposed in the through hole 22.

  The cage 11 is circumferentially spaced to form a pair of annular portions 23 and 24 having different diameters and a pocket 21 for accommodating the needle roller 13, and the pair of annular portions 23 and 24 And a plurality of column portions 25 connected to each other.

  The pocket 21 is substantially rectangular when viewed from the axial direction. The pockets 21 are radially disposed about the rotation axis 12 of the holder 11. On the side wall surface of the pocket 21, an upper roller stopper 26 for preventing the needle roller 13 accommodated in the pocket 21 from falling upward in the axial direction, and in the axial direction of the needle roller 13 accommodated in the pocket 21 Lower roller stoppers 27 and 28 are provided to prevent the lower side from falling off. The upper roller stopper 26 is provided at the radial center of the pocket 21. Further, the lower roller stopper 27 is provided on the inner diameter side of the pocket 21, and the lower roller stopper 28 is provided on the outer diameter side of the pocket 21. The upper roller stopper 26 and the lower roller stoppers 27 and 28 are provided so as to protrude toward the pocket 21 on side wall surfaces on both sides in the circumferential direction of the pocket 21.

  The needle rollers 13 are accommodated in the pocket 21 in a caulking manner. The shape of the end face of the needle roller 13, specifically the end face 16 located on the bearing outer side and the end face 17 located on the bearing inner side is flat.

  The cage 11 is formed with a concavo-convex shape obtained by bending a plate material in the plate thickness direction several times and bending the plate material. Specifically, the holder 11 includes four radially extending disc portions 31, 32, 33, 34 and four axially extending cylindrical portions 36, 37, 38, 39. The four disc portions 31 to 34 have the inside diameters in the order of the first disc portion 31, the second disc portion 32, the third disc portion 33, and the fourth disc portion 34 from the inside diameter side. Is configured to be large. Further, the four cylindrical portions 36 to 39 are arranged in the order of the first cylindrical portion 36, the second cylindrical portion 37, the third cylindrical portion 38, and the fourth cylindrical portion 39 from the inner diameter side. The first cylindrical portion 36 and the second cylindrical portion 37 are configured to extend axially straight. The third cylindrical portion 38 is slightly inclined so that the inner diameter side portion is located axially lower than the outer diameter side portion. On the other hand, the fourth cylindrical portion 39 located on the most outside diameter side is slightly inclined so that the inside diameter side portion is located on the upper side in the axial direction than the outside diameter side portion. The above-mentioned upper roller stopper 26 is provided on the third disc portion 33. Further, the lower roller stopper 27 described above is provided on the second disc portion 32, and the above-described lower roller stopper 28 is provided on the fourth disc portion 34. The above-mentioned inner diameter side annular portion 23 is configured to include the first disc portion 31, a part of the second disc portion 32, the first cylindrical portion 36, and the second cylindrical portion 37. . The above-mentioned annular part 24 on the outer diameter side is configured to include a part of the fourth disc part 34, an outer diameter area bent part 41 to be described later, and a projection 44 to be described later. The column 25 described above is a part of the second disc part 32, the third disc part 33, a part of the fourth disc part 34, the third cylindrical part 38, and the fourth cylindrical part 39 is included.

  The holder 11 includes an outer diameter area bent portion 41 obtained by bending an outer diameter side area of the holder 11 to the inner diameter side. That is, the retainer 11 is provided with an outer diameter area bent portion 41 formed by bending an area located on the outer diameter side of the pocket 21 obliquely to the inner diameter side. The outer diameter area bent portion 41 is an upright wall portion rising in the axial direction. The outer diameter area bent portion 41 is formed to extend continuously in a ring shape. Specifically, the outer diameter area bending portion 41 bends an end portion on the outer diameter side of the fourth disc portion 34 disposed on the most outer diameter side toward the upper side in the axial direction at a predetermined angle. It is formed.

The angle of the outer diameter area bent portion 41, that is, the angle between the surface 42 located on the inner diameter side of the outer diameter area bent portion 41 and the upper surface 43 of the fourth disc portion 34 is shown in FIGS. indicated by angle B ₁ of 3, less than 45 ° beyond the 0 °, preferably at 25 ° or more than 35 °.

  At the tip of the outer diameter area bent portion 41, a protruding portion 44 is provided at a position aligned with each of the pockets 21. That is, the protrusions 44 are directed radially inward to a position aligned with the respective pockets 21. The position aligned with the pocket 21 is a position where the outer peripheral edge of the protrusion 44 overlaps the outer peripheral edge of the pocket 21. That is, the inner edge of the outer diameter area bent portion 41 overlaps the outer edge of the pocket 21.

  The protruding portion 44 protrudes from the outer diameter side edge of the pocket 21 to the inner diameter side so as to contact the end surface 16 of the roller 13 accommodated in the pocket 21. That is, each protrusion 44 abuts on the end surface of the roller accommodated in each pocket 21 to restrict the radial outward movement of the roller. Specifically, the protruding portion 44 is shaped so as to extend continuously from the inner peripheral side edge of the outer diameter area bent portion 41 toward the inner diameter side. That is, the outer diameter area bent portion 41 and the protruding portion 44 are integrally formed.

  The projecting portion 44 is formed at the circumferential position so that the apex of the projecting portion 44 is located at the center of the pocket 21 in the circumferential direction. Specifically, the corner 45 on the side of the surface 42 which is the portion located on the innermost diameter side of the protrusions 44 (the corner 45 located on the most inner diameter side of the protrusions 44) accommodates the pocket 21. It is provided to contact the center of the end face 16 of the needle roller 13. The corner 45 in this case is a corner located on the fourth disc portion 34 side of the projecting portion 44.

  Here, the retainer 11 is provided with three pilot holes 51 and 52. The three pilot holes 51 and 52 become engagement portions for alignment. In FIG. 1, illustration of one of the pilot holes is omitted. The three pilot holes 51 and 52 are provided so as to be spaced apart in the circumferential direction and to penetrate straight in the thickness direction. Each of the three pilot holes 51 and 52 is formed in a round hole shape. The three pilot holes 51, 52 are provided approximately equidistantly, and in this case, provided at intervals of 120 degrees around the rotation axis 12 of the holder 11. Specifically, the pilot holes 51 and 52 are provided at the center in the radial direction in the first disc portion 31 positioned on the innermost side. In addition, as a diameter of the pilot holes 51 and 52, for example, φ 2.5 mm or φ 3 mm is selected.

  In addition, the thrust roller bearing 20 provided with such a cage 11 is configured to include, for example, a plurality of needle rollers 13, a ring 14 positioned on the upper side, and a ring 15 positioned on the lower side. . And, at the time of bearing operation of the thrust roller bearing 20, the needle roller 13 accommodated in the pocket 21 is the raceway surface 18 of the bearing ring 14 located on the upper side in the axial direction and the bearing ring located on the lower side in the axial direction It rolls on the 15 raceways 19. The holder 11 rotates about the rotation axis 12. Moreover, each needle roller 13 accommodated in the pocket 21 performs revolution motion while performing rotation motion. Here, a centrifugal force to the outer diameter side acts on the needle roller 13. The center of the end face 16 of the needle roller 13 is the protrusion 44 provided on the holder 11, and more specifically, the corner 45 located on the innermost side of the protrusion 44 provided on the holder 11 Sliding contact. That is, this corner 45 of the projecting portion 44 is a region in contact with the end face 16 of the needle roller 13.

  Here, the corner 45 is face-pressed. By this face pressing process, the corner 45 does not have a sharp pointed portion, and is smoothly connected to the surface constituting the corner 45. For this reason, the aggressivity to the member by the side which corner 45 contacts is eased.

  Next, a method of manufacturing the cage 11 of a thrust roller bearing according to an embodiment of the present invention will be described. The manufacturing of the thrust roller bearing cage 11 is performed using a transfer press. The transfer press is a relatively inexpensive press device with less complicated apparatus configuration. FIG. 4 is a flowchart showing representative steps of a method of manufacturing the cage 11 of a thrust roller bearing according to an embodiment of the present invention.

  Referring to FIG. 4, first, a holder material to be holder 11 later is prepared (holder material preparation step: step S1). For example, a thin flat steel plate is used as the cage material. Here, the cage material is a plate material cut into a substantially rectangular shape at this stage in order to form the final outer diameter shape of the cage in the later outer shape forming step (step S4). It may be a disk-shaped plate material.

  Next, a concavo-convex shape is formed in the thickness direction on such a cage material (concave-convex shape forming step: step S2). Thereby, even if it is thin-plate shaped holder 11, the length dimension of the rotation axis direction of holder 11 can be secured large, and a roller can be held appropriately.

  Specifically, in this step, the holder material is drawn. In this case, the concavo-convex shape can be formed more efficiently. FIG. 5: is sectional drawing of the holder | retainer raw material after performing an uneven | corrugated shaped formation process. The cross section shown in FIG. 5 corresponds to the cross section shown in FIG. Specifically, referring to FIG. 5, the flat plate-shaped cage material 56 is drawn to form first to fourth disc portions 61 to 64 and first to fourth cylindrical portions. 66-69 are formed. Then, a circular hole-like through hole 57 penetrating in the thickness direction is provided at the center. That is, in this case, the cage material 56 has a so-called mountain-and-valley shape bent in the axial direction a plurality of times.

  Next, a pilot hole as an engaging portion is formed (pilot hole forming step: step S3). FIG. 6 is an enlarged cross-sectional view showing a part of the cage material 56 after the pilot hole forming process is performed. The cross section shown in FIG. 6 corresponds to the portion shown in area VI in FIG. The pilot hole 71 as the engaging portion is provided so as to penetrate straight in the thickness direction at the radial center of the first disc portion 61. The pilot holes 71 are provided in a total of three substantially equidistantly spaced at an interval of 120 degrees in the circumferential direction.

  Thereafter, the outer shape of the holder material 56 is formed (outer shape forming step: step S4). FIG. 7 is an enlarged sectional view showing a part of the cage material 56 after the outer shape forming process is performed. The cross section shown in FIG. 7 corresponds to the portion shown in the region VI in FIG. 2 and is a case where it is cut at the cross section shown by VII-VII in FIG. In this case, specifically, the holder material 56 is punched straight in the thickness direction so that the final outer shape of the holder 11 is obtained by an outer diameter area bending step (step S7) or the like to be performed later. To form. In this case, the outer shape of the cage material 56 can be formed relatively easily and accurately. In this manner, the outer diameter side end 72 of the holder 11, specifically, the outer diameter side end 72 of the fourth disc portion 64 is formed.

  Here, when forming the outer shape, the holder material 56 is punched out so as to form a portion to be the protrusion 70 later. That is, in this case, the outer shape forming step is also a projecting portion forming step of forming the projecting portion. FIG. 8 is a view showing a part of the holder material 56 after the pocket forming process performed after the outer shape forming process is performed. FIG. 8 corresponds to FIG. When punching so as to form the projecting portion 70, positioning in the circumferential direction is performed using a plurality of pilot holes 71. Specifically, a plurality of guide pins (not shown) serving as so-called pencil-shaped positioning jigs whose tip is pointed and whose diameter is gradually increased in a tapered shape are prepared, and a plurality of pilot holes 71 are provided. Insert one by one gradually from one side in the plate thickness direction. Then, positioning is performed by a plurality of guide pins, and the entire outer shape is punched out by a punching device (not shown) in consideration of the position, shape, and the like of the projecting portion 70. By doing this, even if the positions of the punching device and the cage material 56 are somewhat deviated from the positions where the protrusions 70 are accurately provided, a pencil-shaped guide pin with a pointed tip is gradually inserted into the pilot hole 71 In the process of being carried out, punching can be carried out by returning the holder material 56 to the correct position where the projecting portion 70 should be provided with respect to the positional relationship with the punching device. In this case, since three pilot holes 71 are provided, it is possible to prevent the rotation or the like of the holder material 56 when performing positioning, and perform more reliable positioning.

  Next, a pocket is formed (pocket formation step: step S5). FIG. 9 is an enlarged sectional view showing a part of the cage material after the pocket forming process is performed. The cross section shown in FIG. 9 corresponds to the portion shown in the region III in FIG. 2 and is a case where it is cut at the cross section shown by IX-IX in FIG. In this case, the pocket 73 extends over a portion of the second disc portion 62, the third disc portion 63, a portion of the fourth disc portion 64, and the third cylindrical portion 68, and the third Pockets are formed across the four cylindrical portions 69 so as to penetrate the cage material 56 straight in the thickness direction. Here, although not shown in FIG. 9, an upper roller stopper and a lower roller stopper, which are shaped so as to protrude inward in the circumferential direction of the pocket 73, are simultaneously formed. That is, taking into consideration the shapes of the upper roller stopper and the lower roller stopper, the pocket is removed along the outer shape of the needle roller 13 accommodated in the pocket 73. A plurality of pockets 73 may be simultaneously formed by pocket removal, or the pockets 73 may be formed one by one.

  Here, also when forming the pocket 73 in the cage material 56, the positioning between the punching device (not shown) for punching the pocket and the cage material 56 to be punched out is performed using the pilot holes 71. That is, the pocket 73 is formed on the basis of the position where the pilot hole 71 is provided. Also in this case, as in the outer shape forming process described above, positioning in the circumferential direction is performed using the plurality of pilot holes 71. Specifically, in the same manner as described above, a plurality of guide pins as positioning jigs having a pointed pencil shape are prepared, and the tip is gradually inserted into one of the pilot holes 71 from one side in the plate thickness direction. Then, positioning is performed by a plurality of guide pins, and the pocket 73 is punched out by the punching device in consideration of the position, shape, and the like of the pocket 73. By doing this, it is possible to align the circumferential phase of the provided pocket 73 and the protruding portion 70, and to make the positional relationship between the formed pocket 73 and the formed protruding portion 70 appropriate. Therefore, in the positional relationship between the formed protrusion 70 and the formed pocket 73, the protrusion 70 can be formed accurately and efficiently, and the protrusion 44 is formed precisely at an appropriate location. Therefore, the end face 16 of the needle roller 13 and the projection 44 can be properly brought into contact with each other during operation of the bearing. The plurality of pockets 73 may be punched out at the same time, or the pockets 73 may be punched out one by one.

  In the present embodiment, the pilot hole 71 is formed in the region on the inner diameter side of the pocket 73. In this case, the pilot hole 71 can be formed by effectively utilizing the space of the holder 11.

  Further, in the present embodiment, the pilot holes 71 are formed at positions avoiding the locations where the pockets 73 are provided in the circumferential direction. In this case, in the circumferential direction of the holder 11, a local decrease in strength can be avoided. The positional relationship with the pilot holes 71 is arbitrarily determined. In this case, specifically, the plurality of pockets 73 are formed such that the pilot holes 71 are disposed at positions corresponding to the centers of the adjacent pockets 73 in the circumferential direction.

  Next, as shown in FIGS. 8 and 9, an annular groove 79 is formed on the outer diameter side of the pocket 73 in the holder material (groove forming step: step S6). In this step (step S6), in the outer diameter area bending step (step S7) to be described later, the groove 79 is formed at a position serving as a bending start point to form the outer diameter area bent portion 41. By performing the groove forming step (step S6), the region on the outer diameter side of the cage material 56 can be easily bent inward in the outer diameter region bending step (step S7) described later. (Step S6) may be omitted. In addition, the order of steps S4 to S6 is not particularly limited.

  Next, in the cage material 56, the area located on the outer diameter side of the pocket 73 is bent at an inclination angle of 45 ° to the inner diameter side to form an outer diameter area bent portion (outer diameter area bending step) (step S7) ). When the groove formation configuration (step S7) is performed, the outer diameter side area of the cage material 56 is bent to form an outer diameter area bent portion, with the groove 79 as a bending start point.

FIG. 10: is an expanded sectional view which expands and shows a part of holder | retainer raw material of the middle stage of an outer-diameter area | region bending process. 11 and 12 are enlarged cross-sectional views showing a state in which the outer diameter area bending step is performed. FIG. 13 and FIG. 14 are enlarged cross-sectional views showing a part of the cage material 56 after the outer diameter region bending step is performed. The cross sections shown in FIGS. 10 and 13 correspond to the portion shown in region VI in FIG. The cross section shown in FIG. 14 corresponds to the portion shown in region III in FIG. The cross sections shown in FIGS. 11 and 12 show the positional relationship between the region on the further outer diameter side of the portion corresponding to the portion shown in region VI in FIG. 2 of the cage material 56 and the holding members 101 and 102 and the pressing member 103. Show. Here, as shown in FIG. 10, the end portion 72 on the outer diameter side of the annular holder material 56 is bent so as to be straight in the thickness direction over the entire area. That is, the angle B ₂ between the surface 75 located on the inner diameter side of the outer diameter region bent portion 74 and the upper surface 76 of the fourth disc unit 64 is approximately at right angles. The method of bending at a right angle is not particularly limited, and for example, it is performed as follows. As shown in FIG. 11, in the cage material 56, the region excluding the region on the outer diameter side of the fourth disc portion 64 is vertically sandwiched by the holding members 101 and 102 and held, and the fourth disc portion 64 The pressing member 103 is disposed under the area on the outer diameter side of the. Next, as shown in FIG. 12, by pushing up the pressing member 103, the outer diameter side area bending portion 74 can be bent so as to be perpendicular to the fourth disc portion 64.

Thereafter, as shown in FIG. 13 and FIG. 14, the outer diameter side bent portion 74 is bent toward the inner diameter side to form the outer diameter region bent portion 74 bent obliquely to the inner diameter side at an inclination angle of less than 45 °. Do. In this case, the bending angle (tilt angle), that is, the angle between the surface 75 located on the inner diameter side of the outer diameter region bending portion 74 and the upper surface 76 of the fourth disc portion 64 is shown in FIG. represented by an angle _{B 3} in FIG. 14. Angle _{B 3} corresponds to the angle _{B 1} described above. Ie, in equal relationship with angle _{B 1} and the angle _{B 3.} Angle _{B 1} and the angle _{B 3} is less than 45 ° beyond the 0 °, preferably at 25 ° or more than 35 °.

  In this case, since the protrusion 70 is provided at the circumferential center of the pocket 73 in the circumferential positional relationship, the protrusion 70 is formed at an appropriate location. Specifically, the corner portion 77 of the projecting portion 70 located on the fourth disc portion 76 side abuts on the center of the end surface 16 of the needle roller 13. Finally, the surface pressing process of the area of the projecting portion 70 in contact with the end face 16 of the needle roller 13 is performed. Thus, the cage 11 of the thrust roller bearing configured as shown in FIGS. 1 to 3 is manufactured.

  A step of bending the cage material 56 which is bent so that the outer diameter side end portion 72 of the cage material 56 extending in an annular shape is straight in the thickness direction, and a process of performing surface pressing May be performed continuously. FIG. 15 is an enlarged sectional view showing a state in which the outer diameter area bending step is performed. FIG. 16 is an enlarged cross-sectional view showing a state in which the surface pressing process is performed. FIG. 17 is an enlarged cross-sectional view showing the tip of the outer diameter area bent portion after the surface pressing process. Specifically, as shown in FIG. 15, in the cage material 56 in which the outer diameter side region bent portion 74 is bent at a right angle to the fourth disc portion 64, the outer diameter side region bent portion The region on the inner diameter side of the region 74 is vertically sandwiched by the molds 104 and 105 and held. At this time, the outer diameter side edge of the upper mold 104 is positioned more radially inward than the outer diameter side edge of the lower mold 105. Further, a mold 106 for pressing the outer diameter area bent portion 74 downward from above is disposed in contact with the surface 78 located on the outer diameter side of the outer diameter area bent portion 74. The mold 106 abuts on the upper mold 104 and extends in the vertical direction at an inner diameter side end surface 106a, a horizontal surface 106b connected to the inner diameter side end surface 106a and extending to the outer diameter side, and an outer diameter area bent portion 74. A portion 106d having an inner diameter side surface 106c which is abutted with the outer diameter side surface 78 and extends in the vertical direction, and where the horizontal surface 106b and the inner diameter side surface 106c intersect is a round (R) shape. In this state, when the mold 106 is moved downward so that the inner end face 106a follows the outer end face 104a of the mold 104, it is guided by the round portion 106d and the outer diameter area bent part 74 is on the inner diameter side. It can be bent so as to be inclined toward the Thereafter, as shown in FIG. 16, the mold 104 is moved further downward to smooth the corner located on the inner diameter side in the outer diameter area bending portion 74 at the outer diameter side end face 104 a of the mold 104 and the mold 106. The angle located on the outer diameter side in the outer diameter area bent portion 74 is smoothed in the horizontal surface 106 b of As a result, as shown in FIG. 17, it is possible to form a projecting portion 70 in which the area in contact with the end face of the roller is surface-pressed.

  In the above embodiment, the corner portion of the projecting portion located on the fourth disc portion side contacts the center of the end face of the needle roller housed in the pocket, but the following It may be configured as FIG. 18 is a cross-sectional view showing a part of the cage in this case. FIG. 18 corresponds to the cross section of the cage shown in FIG.

  Referring to FIG. 18, a retainer 81 of a thrust roller bearing according to another embodiment of the present invention is provided with a projecting portion 83 at a position where the pocket 85 is formed in the outer diameter area bent portion 82. ing. The projecting portion 83 is configured to contact the center of the end face 16 of the needle roller 13 accommodated in the pocket 85 at the corner portion 84 opposite to the fourth disc portion 86 side. The corner portion 84 is subjected to surface pressing. In addition, in order to set it as such a structure, it is good to carry out processing using a jig with an angle along the corner 84 in the outer diameter area bending step.

  Further, the position where the pilot hole is provided may be a position where the pocket is provided. That is, one of the plurality of pockets provided may be a pilot hole. FIG. 19 is a view showing a part of the cage in this case. Referring to FIG. 19, thrust roller bearing cage 91 according to still another embodiment of the present invention includes a plurality of pockets 92 and a pillar 93 positioned between two adjacent pockets 92. And between the pocket 92 and the pocket 92, the pilot hole 95 is provided in the position of the pillar part 94 in which the pocket 92 should be formed. The pilot holes 95 have a shape in which one pocket 92 of the plurality of pockets 92 provided equidistantly in the circumferential direction is replaced by a pilot hole 95.

  In the above embodiment, the pilot hole is configured to penetrate straight in the thickness direction, but the present invention is not limited to this. For example, the pilot hole may have a tapered wall surface. It may be done. In addition, regardless of the shape of the round hole, a square hole, a triangular hole or the like can be adopted. Although the pilot hole is provided as the engaging portion, the invention is not limited to this, and the engaging portion may be configured by another structure, for example, a notch.

  In the above embodiment, although the drawing process is performed in the concavo-convex shape forming step, the present invention is not limited to this, and the concavo-convex shape may be formed by a process other than the drawing process, for example, a bending process.

  In the above embodiment, although the cage is configured to form the concavo-convex shape in the thickness direction, the present invention is not limited to this, and the cage does not have the concavo-convex shape in the thickness direction, so-called It may be configured to use a cage in the form of two-plate alignment.

  In the above embodiment, the thrust roller bearing provided with such a cage may be configured without the bearing ring. Furthermore, rollers other than needle rollers, for example, rod-like rollers may be used.

  Subsequently, the effects of the cage for the thrust roller bearing of the present embodiment and the method for manufacturing the same will be described. The inventor of the present invention has made it possible to form an outer diameter area bent portion by bending an area located on the outer diameter side with respect to the pocket to the inner diameter side at various inclination angles θ, an outer diameter size of the cage, And about the characteristic about the rotational torque after long-term use, the knowledge of following Table 1 is acquired.

  In Table 1, the radial load is the durability of the projection when the rotary centrifugal force of the roller is applied to the projection in a thrust roller bearing in which the roller is accommodated in the pocket of the cage. "◎" means that the shape of the protrusion can be maintained when the rotational centrifugal force of the roller is very large. "(Circle)" means that the shape of a protrusion part can be maintained, when the rotational centrifugal force of a roller is large. "△" means that the shape of the projecting portion can be maintained when the rotational centrifugal force of the roller is medium (about the rotational centrifugal force of the general thrust roller bearing). "X" means that the shape of the protrusion can not be maintained when the rotational centrifugal force of the roller is medium. That is, ◎, 、, △, x are in the descending order of durability against radial load.

  Further, the outer diameter size is the size of the outer diameter of the cage when the position and the shape of the pocket of the cage are the same. "X" is the outer diameter when the inclination angle is 0 °. “Δ” means that the outer diameter is slightly smaller than when the inclination angle is 0 °. “○” means that the outer diameter is smaller than when the inclination angle is 0 °. “◎” means that the outer diameter is much smaller than when the inclination angle is 0 °. That is, the outer diameters are ◎, 、, △, x in ascending order.

  The torque after a long time is a rotational torque when the thrust roller bearing in which the roller is accommodated in the pocket of the cage is used for a long time. "(Circle)" means that the rotational torque after use for a long time does not fall substantially from the initial rotational torque. “Δ” means that the rotational torque after being used for a long time is slightly reduced from the initial rotational torque. "X" means that the rotational torque after prolonged use is significantly reduced from the initial rotational torque. That is, ○, 小 さ い, and x are in ascending order of decrease in rotational torque after long time use.

  As shown in Table 1, in Examples 1 to 7 formed by bending the region where the bent portion is on the outer diameter side of the pocket to the inner diameter side at an inclination angle of less than 45 °, the rotational centrifugal force of the roller (inner diameter Durability against radial load when the thrust roller bearing rotates because it is easy to withstand the load from the roller and maintain its shape when a force (biased toward the outer diameter side from the side) is applied to the projection Can maintain In light of durability against radial load, the inclination angle θ is preferably 40 ° or less, and more preferably 35 ° or less. On the other hand, in Comparative Examples 1 to 3 in which the inclination angle is 45 ° or more, when the rotary centrifugal force of the roller is applied to the projecting portion, the roller rises so as to increase the inclination angle (to approach 90 °), The durability against radial load can not be maintained.

  In addition, since the outer diameter area bent portion in Examples 1 to 7 is formed by bending the area located on the outer diameter side of the pocket toward the inner diameter side at an inclination angle of less than 45 °, as described in Patent Document 1 above. As compared with the case where the inclination angle is 0 ° (Comparative Example 1), the area in contact with the roller in the projecting portion is smaller. Specifically, in Patent Document 1 in which the inclination angle is 0 °, the entire tip end surface of the convex portion contacts the center of the end surface of the roller housed in the pocket, while in Examples 1 to 7, the protrusion portion The corner located on the inner diameter side at the tip end face of the roller contacts the center of the end face of the roller housed in the pocket, and is in a state close to point contact rather than surface contact. When the roller is urged from the axial center toward the outer diameter side by the rotational centrifugal force of the roller, the portion in contact with the roller in the projection becomes friction, so the area in contact with the roller is small. Since the protrusion of can reduce the rotational resistance, the rotational torque can be reduced.

  Therefore, in the thrust roller bearing cage according to the present embodiment and the method of manufacturing the same, the outer diameter area bent portion is formed by bending the area located on the outer diameter side of the pocket toward the inner diameter side at an inclination angle θ of less than 45 °. Therefore, the rotational torque can be reduced, and the durability against radial load when the thrust roller bearing rotates can be maintained.

  Since the inclination angle θ is less than 45 °, the height of the outer diameter area bent portion 41 can be easily adjusted. In this case, the protrusion can be easily brought into contact with the center of the roller. In addition, even if the portion in contact with the roller in the projection wears, it is easy to maintain the projection contacting the center of the roller. In Patent Document 1 in which the inclination angle is 0 °, the contact with the rollers depends on the thickness of the cage.

  Further, as shown in Table 1, the outer diameter can be reduced by setting the inclination angle θ to 25 ° or more. For this reason, the area | region which receives a roller can be enlarged with respect to the whole holder | retainer.

  In addition, as shown in Table 1, in Examples 1 to 7 in which the inclination angle is less than 45 °, even if the thrust roller bearing is used for a long time and the portion in contact with the roller in the projection wears, Since the increase in the area of the portion in contact with the roller (the contact area with the roller in the protrusion after abrasion) is small, it is possible to suppress the reduction of the rotational torque. When the protrusion wears by using the cage for a long time, the area in contact with the roller increases, but since the rate of the increase is low, it is possible to suppress the decrease in rotational torque after long-term use, the inclination angle As for (theta), 25 degrees or more and 40 degrees or less are preferable.

  Furthermore, as shown in Table 1, by setting the inclination angle θ to 25 ° or more and 35 ° or less, all of the evaluations of the radial load, the outer diameter size, and the torque after a long time are ○. That is, by setting the inclination angle θ to 25 ° or more and 35 ° or less, durability against radial load, downsizing, and suppression of reduction in rotational torque after long time use can be performed.

  It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is indicated not by the embodiments described above but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

  A thrust roller bearing cage according to the present invention, and a method of manufacturing the same, when a high performance thrust roller bearing cage and a more efficient manufacture of such thrust roller bearing cage are required , To be used effectively.

  11, 81, 91 cage, 12 rotation axis, 13 rollers, 14, 15 bearing ring, 16, 17 end face, 18, 19 bearing surface, 20 thrust roller bearing, 21, 73, 85, 92 pocket, 22, 57 penetration Holes 23, 24 annular parts 25, 93, 94 pillars 26, 26, 28 Rollers 31, 31, 33, 33, 64, 62, 63, 64, 86 Disc parts 36, 37, 38, 39, 66, 67, 68, 69 cylindrical part, 41, 74, 82 outer diameter area bent part, 42, 43, 75, 76, 78 faces, 44, 70, 83 protrusions, 45, 77, 84 corners Part, 51, 52, 71, 95 pilot hole, 56 retainer material, 72 end, 79 groove, 101, 102 holding member, 103 pressing member, 104, 105, 106 mold, 104a outer diameter end face, 106 a Inner diameter side end face, 106b horizontal surface, 106c inner diameter side face, 106d part.

Claims (5)

A thrust roller bearing cage provided in a thrust roller bearing and provided with a plurality of pockets for accommodating rollers,
An outer diameter area bent portion formed by bending an outer diameter side end portion of an area located on the outer diameter side with respect to the pocket toward the inner diameter side at an inclination angle of 25 ° or more and 35 ° or less ;
It is provided at the tip of the outside diameter area bending portion at a position aligned with each of the pockets, and protrudes inward from the outside diameter edge of the pocket so as to contact the end face of the roller housed in the pocket A retainer for a thrust roller bearing, comprising: The thrust roller bearing retainer according to claim 1, wherein a region of the protrusion in contact with the end surface of the roller is face-pressed. A manufacturing method of a thrust roller bearing cage provided with a thrust roller bearing and provided with a plurality of pockets for accommodating rollers,
Preparing a cage material to be a cage;
Forming an outer shape having a portion serving as a projecting portion projecting from the outer edge of the pocket to the inner diameter side so as to contact the end surface of the roller housed in the pocket with respect to the cage material When,
Forming the pocket with respect to the retainer material;
A step of forming an outer diameter area bent portion by bending the outer diameter side end portion of the region positioned on the outer diameter side of the pocket in the cage material at an inclination angle of 25 ° to 35 ° to the inner diameter side And a method of manufacturing a thrust roller bearing cage. The method for manufacturing a thrust roller bearing retainer according to claim 3 , further comprising the step of performing a surface pressing process on a region of the projecting portion in contact with the end surface of the roller. The method further includes the step of forming an annular groove in a region located on the outer diameter side of the pocket with respect to the holder material,
The thrust roller bearing according to claim 3 or 4, wherein, in the step of forming the outer diameter region bent portion, the outer diameter region bent portion is formed by bending the groove toward the inner diameter side with the groove as a bending starting point. Method of the container.

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