Shell-shaped needle bearing

Abstract

The utility model provides a shell-shaped needle roller bearing which can ensure the strength of a retainer and can stably guide needle rollers through the retainer when a circumferential gap between adjacent needle rollers is narrow. The shell-shaped needle bearing is characterized in that: pressing surfaces (10) are formed on both side surfaces in the circumferential direction of the column center section (8c) so that the cross-sectional shape of the column center section (8c) forms a trapezoid in which the width in the circumferential direction gradually narrows toward the outside in the radial direction, the pressing surfaces (10) corresponding to the bevel edges of the trapezoid, and pressing surfaces (10) are formed on both side surfaces in the circumferential direction of the column center section (8c); groove-shaped relief parts (12) are provided so that the side surfaces on both sides in the circumferential direction of the column inclined part (8b) are recessed in the circumferential direction with respect to the press surface (10), and the relief parts (12) extend in the radial direction on the side surfaces on both sides in the circumferential direction of the column inclined part (8b).

Description

TECHNICAL FIELD

[0001] The utility model relates to shell shape needle bearing. BACKGROUND

[0002] Compared with other forms of rolling bearings, the shell-shaped outer ring type needle bearing has a small radial thickness and a high load capacity, and is therefore widely used in the fields of automobiles and industrial machines (for example, Patent Literature 1).

[0003] The shell-shaped needle bearing of Patent Literature 1 has a shell-shaped outer ring formed by drawing processing of a steel sheet, a plurality of needles arranged at intervals in the circumferential direction along the inner periphery of the shell-shaped outer ring, and a retainer that maintains the circumferential intervals of the plurality of needles.

[0004] The retainer has a pair of ring portions that face each other in the axial direction with the needles interposed therebetween, and a plurality of column portions that pass through the needles adjacent in the circumferential direction and link the pair of ring portions. Here, the circumferentially adjacent column portions and the pair of ring portions form pockets that accommodate the needles. The plurality of pockets are sequentially formed by blanking processing of a strip steel that becomes the retainer, the strip steel in which the pockets are formed is cut to a predetermined length and bent into a cylindrical shape, and the both ends of the strip steel bent into the cylindrical shape are welded, whereby the retainer is formed.

[0005] In addition, each column portion that constitutes the retainer has a pair of column end portions that extend from the pair of ring portions toward the axial inner side with a constant outer diameter, a pair of column inclined portions that extend obliquely with the outer diameter gradually becoming smaller toward the axial inner side from the pair of column end portions, and a column central portion that links the pair of column inclined portions. The circumferential side surface of the column portion (the column end portion, the column inclined portion, and the column central portion) maintains the blanking cross section formed by the blanking processing of the pocket, and thus the cross-sectional shape of the column portion becomes a square shape in which the circumferential width is constant along the radial direction.

[0006] Patent Literature 1: Japanese Patent Application Publication No. 2007-16828

[0007] The inventors of the present application have studied the following: In the shell-shaped needle bearing like that of Patent Literature 1, in order to increase the load capacity, the number of needles is increased without changing the bearing size.

[0008] That is, in the shell-shaped needle bearing like that of Patent Literature 1, in the case where the number of needles is increased without changing the bearing size, the circumferential gap between the adjacent needles becomes narrow. Therefore, the circumferential width of the column central portion of the retainer arranged between the circumferentially adjacent needles also needs to be reduced, and the strength of the retainer is reduced. Thus, the inventors of the present application have focused on the fact that the circumferential gap between the adjacent needles has a shape in which the width gradually becomes wider toward the radial inner side from the position of the pitch circle of the needles, and have studied that the circumferential width of the column central portion of the retainer is ensured by making the position of the column central portion of the retainer closer to the radial inner side than in the past.

[0009] However, in a case where the position of the central portion of the column of the retainer is made close to the radially inner side, there is a concern that the position at which the needle contacts the central portion of the column becomes a corner portion of the radially outer end of the circumferential side surface of the central portion of the column, and in this case, there is a concern that the central portion of the column is pressed toward the radially inner side to contact the shaft because the needle becomes a form of climbing over the central portion of the column. Utility model content

[0010] The utility model wants to solve the subject in providing even when adjacent needle each other's circumferential gap is narrow can ensure the strength of retainer and can guide the needle of the shell needle bearing stably through the retainer.

[0011] In order to solve the above-mentioned problem, in the utility model, the shell needle bearing with the following structure is provided.

[0012] [structure 1]

[0013] A shell needle bearing has:

[0014] Shell outer ring;

[0015] A plurality of needles are arranged in a circumferential direction at intervals along the inner periphery of the shell outer ring;And

[0016] Retainer, the circumferential interval of the plurality of needles is kept,

[0017] The retainer has: a pair of annular portions, which are opposite in the axial direction through the needle;And a plurality of column portions, which pass through the circumferentially adjacent needles and connect the pair of annular portions,

[0018] Each column portion has: a pair of column end portions, which extend from the pair of annular portions to the inner side of the axial direction with a constant outer diameter;A pair of column inclined portions, which are inclined and extended in a manner that the outer diameter gradually decreases from the pair of column end portions toward the inner side of the axial direction;And a column central portion, which connects the pair of column inclined portions,

[0019] The shell needle bearing is characterized in that,

[0020] In a manner that the cross-sectional shape of the column central portion is trapezoidal, the contact surface of the outer periphery of the needle is formed on the side surface of the circumferential both sides of the column central portion, the pressure machining surface corresponding to the inclined side of the trapezoidal is formed, the pressure machining surface is formed in a manner that the circumferential both sides of the column inclined portion are recessed relative to the pressure machining surface, the groove-shaped avoiding portion is provided in a manner that the circumferential both sides of the column inclined portion are recessed relative to the pressure machining surface, and the avoiding portion extends in the radial direction along the circumferential both sides of the column inclined portion.

[0021] If this structure is adopted, the side surfaces on both sides in the circumferential direction of the column central portion are formed with press surface processed surfaces in a manner that the cross-sectional shape of the column central portion is a trapezoid in which the circumferential width gradually narrows toward the radially outer side, and the press surface processed surfaces correspond to the oblique sides of the trapezoid, so when the rollers come into contact with the column central portion, they come into contact with the press surface processed surfaces, and do not come into contact with the portions of the corners of the radially outer ends of the circumferential side surfaces of the column central portion. Therefore, even in the case where the position of the column central portion is made to be closer to the radially inner side in order to narrow the circumferential gap between adjacent rollers, it is possible to prevent the rollers from becoming a form of climbing up the column central portion, and it is possible to stably guide the rollers. In addition, the cross-sectional shape of the column central portion is formed as a trapezoid in which the circumferential width gradually narrows toward the radially outer side, so when the circumferential gap between adjacent rollers is narrow, it is easy to make the circumferential width of the column central portion large, and it is easy to ensure the strength of the retainer.

[0022] In addition, the circumferential side surface of the column inclined portion is formed with a relief portion that is recessed in the circumferential direction with respect to the press surface processed surface, so when a mold having a recessed portion of a cross-sectional trapezoid is pressed against the column central portion to plastically process the column central portion into a cross-sectional trapezoid, it is possible to prevent the mold from interfering with the column inclined portion, and to make the mold come into contact with only the column central portion. Therefore, it is possible to stably form the press surface processed surface (the surface corresponding to the oblique side of the trapezoid) of the column central portion.

[0023] In addition, a gap in the circumferential direction is formed between the relief portion and the roller, and this gap functions as a flow path for oil that lubricates the inside of the spherical roller bearing, so it is possible to prevent the oil film of the roller from breaking.

[0024] [Structure 2]

[0025] According to the spherical roller bearing described in Structure 1, wherein

[0026] the column end portion is formed in a manner that the outer diameter of the column end portion is larger than the outer diameter of the column central portion, and the inner diameter of the column end portion is smaller than the outer diameter of the column central portion,

[0027] end portion guide surfaces are formed on the side surfaces on both sides in the circumferential direction of the column end portion, the end portion guide surfaces extend at right angles to the circumferential direction in a manner that they cross the press surface processed surfaces when viewed in the axial direction, and come into contact with the outer periphery of the roller.

[0028] If this structure is adopted, the column end portion is formed in a manner that the outer diameter of the column end portion is larger than the outer diameter of the column central portion, and the inner diameter of the column end portion is smaller than the outer diameter of the column central portion, so when viewed in the axial direction, the column central portion and the column end portion are in a positional relationship in which they overlap, and the shape of the column portion becomes a shape in which the change in position in the radial direction is small along the axial direction. Therefore, when the rollers come into contact with the column central portion, it is not easy for a torsion force around the axial direction to occur in the column portion, and it is possible to improve the durability of the retainer.

[0029] Further, an end guide surface in contact with the outer periphery of the needle roller is formed at the column end portion, so that the axial distance from the contact position of the needle roller with the column end portion to the root of the column portion is short. Therefore, the moment load acting on the position of the root of the column portion due to the contact of the needle roller can be suppressed, and the needle roller is guided.

[0030] [Structure 3]

[0031] According to the shell-shaped needle bearing described in Structure 2, in the shell-shaped needle bearing,

[0032] An R corner portion in a concave circular arc shape connecting the end guide surface and the side surface on the inner side in the axial direction of the annular portion is formed.

[0033] If this structure is employed, the R corner portion is provided so as not to have a portion concave in the circumferential direction with respect to the end guide surface, so that the rigidity of the root of the column portion can be ensured, and the stress concentration at the root of the column portion is moderated by the R corner portion.

[0034] [Structure 4]

[0035] According to the shell-shaped needle bearing described in Structure 2 or 3, in the shell-shaped needle bearing,

[0036] The surface roughness of the pressure surface is smaller than the surface roughness of the end guide surface.

[0037] If this structure is employed, the surface roughness of the pressure surface is small, so that the occurrence of oil film rupture when the needle bearing contacts the pressure surface can be prevented. Therefore, even in the case where low-viscosity oil is used as the oil for lubricating the inside of the shell-shaped needle bearing, the bearing life can be ensured.

[0038] [Structure 5]

[0039] According to the shell-shaped needle bearing described in any one of Structures 2 to 4, in the shell-shaped needle bearing,

[0040] A convex circular arc-shaped central side R portion smoothly connecting the pressure surface and the escape portion and a convex circular arc-shaped end portion side R portion smoothly connecting the end guide surface and the escape portion are provided.

[0041] If this structure is employed, the pressure surface is smoothly connected to the escape portion via the convex circular arc-shaped central side R portion, and the end guide surface is smoothly connected to the escape portion via the convex circular arc-shaped end portion side R portion, so that the occurrence of oil film rupture when the needle roller contacts the pressure surface or the end guide surface can be prevented.

[0042] [Structure 6]

[0043] According to the shell-shaped needle bearing described in any one of Structures 2 to 5, in the shell-shaped needle bearing,

[0044] The position at which the end guide surface intersects the press surface is within 90% of the radial outer end of the press surface, as viewed in the axial direction.

[0045] If this structure is employed, the circumferential play between the end outer periphery of the needle and the end guide surface is small, so the skewing of the needle (inclination in the axial direction of the needle) can be effectively prevented.

[0046] [Structure 7]

[0047] The shell needle bearing according to any one of structures 1 to 6, wherein

[0048] The distance from the radial inner end of one of the pair of column end portions that are opposed in the circumferential direction across the respective needles to the radial inner end of the other column end portion is set to be 90% or more and 110% or less of the outer diameter of the needle.

[0049] If this structure is employed, the circumferential play between the end outer periphery of the needle and the column end portion is small, so the skewing of the needle (inclination in the axial direction of the needle) can be effectively prevented.

[0050] The shell needle bearing according to the present application is characterized in that the column central portion is formed with a press surface on both sides in the circumferential direction in a manner that the cross-sectional shape of the column central portion is a trapezoid in which the circumferential width gradually narrows toward the radial outer side, and the press surface corresponds to the oblique side of the trapezoid. Therefore, when the needle contacts the column central portion, the press surface is contacted, and the corner portion of the radial outer end of the circumferential side surface of the column central portion is not contacted. Therefore, even in the case where the position of the column central portion is made to be close to the radial inner side in order to narrow the circumferential gap between the adjacent needles, the needle can be prevented from being in a form of climbing the column central portion, and the needle can be stably guided. In addition, the cross-sectional shape of the column central portion is formed as a trapezoid in which the circumferential width gradually narrows toward the radial outer side, so when the circumferential gap between the adjacent needles is narrow, the circumferential width of the column central portion can be easily made large, and the strength of the retainer can be easily ensured.

[0051] In addition, the relief portion in which the circumferential side surface of the column inclined portion is recessed in the circumferential direction with respect to the press surface is formed, so when a mold having a recessed portion of a cross-sectional trapezoid is pressed against the column central portion to plastically process the column central portion into a cross-sectional trapezoid, the mold can be prevented from interfering with the column inclined portion, and the mold can be made to contact only the column central portion. Therefore, the press surface (the surface corresponding to the oblique side of the trapezoid) of the column central portion can be stably formed.

[0052] Further, a circumferential gap is formed between the avoidance portion and the needle, and the gap functions as a flow path of oil for lubricating the inside of the shell-shaped needle bearing, so that the oil film of the needle can be prevented from breaking. BRIEF DESCRIPTION OF DRAWINGS

[0053] Figure 1 is a sectional view of the shell-shaped needle bearing according to an embodiment of the present application.

[0054] Figure 2 is a view of the needle and the retainer of the shell-shaped needle bearing according to Figure 1 from the outer diameter side.

[0055] Figure 3 is a sectional view along the III-III line of Figure 2 .

[0056] Figure 4 is a sectional view along the IV-IV line of Figure 2 .

[0057] Figure 5 is a view showing the vicinity of the end portion of the pocket of the retainer shown in Figure 2 .

[0058] Figure 6 is a partial perspective view of the retainer shown in Figure 2 .

[0059] Figure 7 is a view showing the state in which the needle shown in Figure 4 is in contact with the pressing surface of the column central portion.

[0060] Figure 8 is a view showing the contact position of the needle shown in Figure 7 and the column central portion, as viewed in the circumferential direction.

[0061] Figure 9 is a view showing the state in which the needle shown in Figure 4 is in contact with the end guide surface of the column end portion.

[0062] Figure 10 is a view showing the contact position of the needle shown in Figure 9 and the column central portion, as viewed in the circumferential direction.

[0063] BRIEF DESCRIPTION OF DRAWINGS

[0064] 1…shell-shaped outer ring; 2…rolling pin; 3…retainer; 7…annular portion; 8…column portion; 8a…column end portion; 8b…column inclined portion; 8c…column central portion; 9…pocket; 10…press surface machined surface; 11…end portion guide surface; 12…avoidance portion; 13…central side R portion; 14…end portion side R portion; 15…corner R portion; d1…outer diameter of column end portion; d2…inner diameter of column end portion; d3…outer diameter of column central portion; S…shaft. DETAILED DESCRIPTION

[0065] Figure 1 A shell-shaped rolling pin bearing according to an embodiment of the present application is shown. The shell-shaped rolling pin bearing has a shell-shaped outer ring 1, a plurality of rolling pins 2, and a retainer 3.

[0066] The shell-shaped outer ring 1 has a cylindrical portion 4 and a pair of flange portions 5 extending to the inner side in the radial direction from both axial ends of the cylindrical portion 4. A cylindrical outer ring raceway surface 6 is formed on the inner periphery of the cylindrical portion 4, and the outer ring raceway surface 6 is in rolling contact with the rolling pins 2. The shell-shaped outer ring 1 is a press-machined member formed by deep drawing a circular steel sheet into a bottomed cylindrical shape. The thickness of the portion of the cylindrical portion 4 of the shell-shaped outer ring 1 in which the outer ring raceway surface 6 is formed is set to a range of 0.5 mm or more and 1.2 mm or less (preferably 1.0 mm or less).

[0067] The axial direction refers to a direction parallel to the central axis of the shell-shaped outer ring 1 (the central axis of the bearing), the radial direction refers to a direction perpendicular to the central axis of the shell-shaped outer ring 1, and the circumferential direction refers to a direction along the circumference that encircles the central axis of the shell-shaped outer ring 1. The retainer 3 is formed symmetrically with respect to the axial center. The inner axial side refers to a direction approaching the axial center of the retainer 3 in the axial direction, and the outer axial side refers to a direction away from the axial center of the retainer 3 in the axial direction.

[0068] The rolling pins 2 are rollers having a cylindrical outer periphery with a constant outer diameter. The rolling pins 2 are arranged at constant intervals in the circumferential direction along the outer ring raceway surface 6 of the inner periphery of the shell-shaped outer ring 1. The diameter of the rolling pins 2 is 6 mm or less, and the axial length of the rolling pins 2 is 3 times or more and 10 times or less the diameter of the rolling pins 2.

[0069] The retainer 3 has a pair of annular portions 7 that face each other in the axial direction with the plurality of rolling pins 2 interposed therebetween, and a plurality of column portions 8 that pass between the rolling pins 2 adjacent in the circumferential direction and link the pair of annular portions 7. The pair of annular portions 7 are arranged in opposition to the side surfaces of the axial inner sides of the pair of flange portions 5 of the shell-shaped outer ring 1, respectively, and the pair of annular portions 7 are in contact with the pair of flange portions 5, thereby restricting the axial movement of the retainer 3 with respect to the shell-shaped outer ring 1. The retainer 3 is a steel retainer formed by welding the ends of a circular ring-shaped steel band having a plurality of pockets 9 formed at equal intervals in the circumferential direction. The retainer 3 is a roller-guided retainer that is positioned in the radial direction by being in contact with each of the rolling pins 2 without being in contact with the cylindrical portion 4 of the shell-shaped outer ring 1.

[0070] As Figure 2 shown, the circumferentially (in the figure, the up-and-down direction) adjacent column portions 8 and the pair of ring portions 7 form pockets 9 that accommodate the needle rollers 2. The pockets 9 are square through openings formed through the retainer 3 in the radial direction (in the figure, the direction perpendicular to the paper surface). The retainer 3 accommodates the needle rollers 2 in each of the pockets 9, and the circumferential spacing of the plurality of needle rollers 2 is maintained by bringing the column portions 8 that divide the each of the pockets 9 in the circumferential direction into contact with the needle rollers 2.

[0071] As Figure 3 shown, the column portions 8 have a pair of column end portions 8a that extend to the axially inner side from the pair of ring portions 7 with a constant outer diameter dl, a pair of column inclined portions 8b that extend obliquely with the outer diameter gradually decreasing toward the axially inner side from the pair of column end portions 8a, and a column central portion 8c that links the pair of column inclined portions 8b. The column central portion 8c extends in the axial direction with a constant outer diameter d3 and links the axially inner ends of the pair of column inclined portions 8b to each other. The column end portions 8a are formed so that the outer diameter dl of the column end portions 8a is larger than the outer diameter d3 of the column central portion 8c and the inner diameter d2 of the column end portions 8a is smaller than the outer diameter d3 of the column central portion 8c.

[0072] Each of the ring portions 7 is formed in a circular ring shape that extends in the circumferential direction along the axial end surface of the needle roller 2. The cross-sectional shape of each of the ring portions 7 is formed in a square shape having the same radial height as the radial thickness of the column end portions 8a. The retainer 3 is a V-shaped retainer in which the ring portions 7 and the column portions 8 are V-shaped when viewed in the circumferential direction. The radial thicknesses of the ring portions 7 and the column end portions 8a are set to be a size of 10% or more (preferably 20% or more, and more preferably 35% or more) of the roller diameter of the needle roller 2.

[0073] As Figure 4 shown, the positional relationship of the column central portion 8c and the column end portions 8a is set so as to have a portion in which the column central portion 8c coincides with the column end portions 8a when viewed in the axial direction. In the figure, the radial thickness of 10% or more (preferably 20% or more, and more preferably 30% or more) of the entire radial thickness of the column central portion 8c from the radially outer end of the column central portion 8c toward the radially inner side becomes the positional relationship in which the column central portion 8c coincides with the column end portions 8a. The column end portions 8a are formed in a cross-sectional square shape in which the circumferential width is constant along the radial direction.

[0074] As Figure 6As shown, a press surface processed surface 10 is formed on the side surface on both circumferential sides of the column central portion 8c. The press surface processed surface 10 is a flat surface formed by performing processing (press surface processing) of plastically deforming the column central portion 8c into a trapezoidal cross section by pressing a die having a recess with a trapezoidal cross section from the radially outer side against the column central portion 8c. By forming this press surface processed surface 10, the cross-sectional shape of the column central portion 8c becomes a trapezoid in which the circumferential width gradually narrows toward the radially outer side (in the drawing, the upper side). The press surface processed surface 10 is a surface corresponding to the oblique side of the isosceles trapezoid that is the cross-sectional shape of the column central portion 8c. The radially outer end of the press surface processed surface 10 intersects the circumferential end of the outer diameter surface of the column central portion 8c at an obtuse angle. The press surface processed surface 10 is formed over a region of 20% or more of the entire radial thickness of the column central portion 8c from the radially outer end of the column central portion 8c toward the radially inner side. The press surface processed surface 10 can also be formed over a region of 40% or less of the entire radial thickness of the column central portion 8c from the radially outer end of the column central portion 8c toward the radially inner side. The press surface processed surface 10 has a surface roughness that is smaller than before the press surface processing is performed, and thus the surface roughness of the press surface processed surface 10 (the surface roughness of the press surface processed surface 10 measured in the axial direction) is smaller than the surface roughness of the end guide surface 11 described later (the surface roughness of the end guide surface 11 measured in the axial direction).

[0075] As shown, Figure 7 The distance from the radially inner end of one of the pair of column central portions 8c opposite each other with the needle 2 to the radially inner end of the other column central portion 8c is smaller than the outer diameter of the needle 2. Thus, in the state where the shaft S is not present, when the needle 2 moves toward the radially inner side, the pair of column central portions 8c opposite each other with the needle 2 restricts the movement of the needle 2 toward the radially inner side, and prevents the needle 2 from falling toward the radially inner side from the pocket 9.

[0076] As shown, Figure 2 A relief portion 12 is formed on the side surface on both circumferential sides (in the drawing, the upper and lower sides) of the column inclined portion 8b, and the relief portion 12 recesses the side surface on both circumferential sides of the column inclined portion 8b in the circumferential direction (in the drawing, the upward and downward directions) with respect to the press surface processed surface 10. The relief portion 12 is a groove-shaped recess that penetrates the circumferential side surface of the column inclined portion 8b in the radial direction (in the drawing, the direction perpendicular to the paper surface) and extends. The relief portion 12 is formed so as to be contiguous with the axial ends (in the drawing, the left and right ends) of the press surface processed surface 10. The press surface processed surface 10 is continuously formed without interruption in the axial direction between the pair of relief portions 12 on both axial sides of the press surface processed surface 10.

[0077] As shown, Figure 4As shown, a flat end guide surface 11 is formed on the side surface of the column end portion 8a on both circumferential sides (left and right sides in the drawing) thereof, and extends in a direction that is at right angles to the circumferential direction. The end guide surface 11 is disposed so as to intersect the press surface processed surface 10 as viewed in the axial direction (direction perpendicular to the plane of the drawing). In addition, the end guide surface 11 is formed so that the position at which the end guide surface 11 intersects the press surface processed surface 10 as viewed in the axial direction is within a range of 90% or less (preferably 70% or less) of the radial outer end (upper end in the drawing) of the press surface processed surface 10.

[0078] The radial outer end of the end guide surface 11 perpendicularly intersects the end of the outer diameter surface of the column end portion 8a in the circumferential direction. In the drawing, the entire radial thickness of the column end portion 8a is taken as the end guide surface 11, but the end guide surface 11 can be formed so as to extend over an area of 10% or more (preferably 20% or more, more preferably 50% or more) of the entire radial thickness of the column end portion 8a from the radial outer end of the column end portion 8a toward the radial inner side. In addition, the end guide surface 11 can be formed so as to extend over an area of 10% or more (preferably 20% or more, more preferably 50% or more) of the entire radial thickness of the column end portion 8a from the radial inner end of the column end portion 8a toward the radial outer side. Figure 7 The distance (the shortest distance connecting with a straight line) from the radial inner end of one of the pair of column end portions 8a (specifically, the radial inner end of the circumferential side surface of the one column end portion 8a on the side opposite the other column end portion 8a) to the radial inner end of the other column end portion 8a (specifically, the radial inner end of the circumferential side surface of the other column end portion 8a on the side opposite the one column end portion 8a) of the one column end portion 8a that is opposite the other in the circumferential direction of the needle 2 is set to be 90% or more and 110% or less of the outer diameter of the needle 2.

[0079] As shown, the press surface processed surface 10 is formed so as to be flat and to extend in the axial direction. In addition, the press surface processed surface 10 is formed so as to be flat and to extend in the circumferential direction. Figure 5 As shown, a convex circular arc-shaped central side R portion 13 that smoothly connects the press surface processed surface 10 and the relief portion 12 is formed on the axial outer end (left end in the drawing) of the press surface processed surface 10 as viewed in the radial direction, and a convex circular arc-shaped end portion side R portion 14 that smoothly connects the end guide surface 11 and the relief portion 12 is also formed on the axial inner end (right end in the drawing) of the end guide surface 11. In addition, a concave circular arc-shaped corner R portion 15 that connects the end guide surface 11 and the side surface of the circular ring portion 7 on the axial inner side (right side in the drawing) thereof in such a way that no portion is concave in the circumferential direction (up and down direction in the drawing) with respect to the end guide surface 11 is formed.

[0080] The retainer 3 can be manufactured as follows.

[0081] First, a strip steel that is a material of the retainer 3 is roll formed in such a way that the cross-sectional shape at right angles to the length direction is V-shaped. Next, the Figure 2 pockets 9 shown are formed by blanking processing of the strip steel. By this blanking processing, the Figure 5The axial inner side of the annular portion 7, the corner R portion 15, the circumferential side of the column end 8a, the end side R portion 14, the clearance portion 12, the central side R portion 13, and the circumferential side of the column center portion 8c (the side before forming the pressing surface 10) are shown. Here, the blanking process is performed by blanking from the side corresponding to the radial outer side of the retainer 3 toward the side corresponding to the radial inner side. As a result, a shear surface and a fracture surface are formed sequentially from the radial outer side to the radial inner side on the circumferential side of the column end 8a, and the shear surface becomes the end guide surface 11. The shear surface is a smooth surface that extends straight along the plate thickness direction (the blanking direction), and the fracture surface is an irregular uneven surface caused by the breaking of the steel strip material. Then, a die (not shown) with a concave portion having a trapezoidal cross-section is pressed from the side corresponding to the radial outer side of the retainer 3 onto the column center portion 8c to plastically deform the column center portion 8c into a trapezoidal cross-section (pressing process), thereby... Figure 4 The pressure-processed surfaces 10 on both sides of the central portion 8c of the column are shown. Then, the strip steel is cut to a specified length and bent into a cylindrical shape. The two ends of the bent cylindrical strip steel are welded together, and finally, heat treatment is performed to obtain... Figure 1 Holder 3 is shown.

[0082] As described below, the retainer 3 has the pressure surface 10 and the end guide surface 11 in contact with the outer periphery of the needle roller 2, thereby maintaining the circumferential spacing of the needle roller 2.

[0083] That is, when Figure 1 When the shell-type needle roller bearing shown rotates, the radial load applied to the shell-type needle roller bearing is supported by a portion of the needle rollers 2 in the region (load region) directly passing through which the radial load is applied, among all the needle rollers 2 arranged around the circumference. Furthermore, the needle rollers 2 are particularly prone to hysteresis and lead in this load region, resulting in contact with the post portion 8 of the cage 3. Additionally, Figure 1 When the shell-shaped needle roller bearing shown is used in a horizontal position with its axis in the direction of the axis, the retainer 3 drops due to its own weight, and the center position of the retainer 3 is eccentric to the downward side relative to the center position of the outer ring.

[0084] Therefore, when the load area is located in the lower half of the circumference of the shell-type needle roller bearing, such as Figure 7 , Figure 8 As shown, the outer periphery of the needle roller 2 located in the load area contacts the pressure-machined surface 10 of the central portion 8c of the column. Here, the radial position of the needle roller 2 within the radial thickness range of the column end 8a contacts the pressure-machined surface 10. Figure 8 (The symbol P1 indicates the contact position between the needle roller 2 and the column 8). Therefore, it is not easy to generate axial torque in the column 8.

[0085] Furthermore, when viewed from the axial direction, the end guide surface 11 and the pressure surface 10 are configured to intersect within 90% (preferably within 70%) of the radial outer end of the pressure surface 10. Therefore, the circumferential clearance between the outer periphery of the end of the needle roller 2 and the end guide surface 11 is small, which can effectively prevent the skewing of the needle roller 2 (the axial direction of the needle roller 2 is tilted).

[0086] On the other hand, when the load area is located in the upper half of the circumference of the shell-type needle roller bearing, such as Figure 9 , Figure 10 As shown, the outer periphery of the end of the needle roller 2 located in the load area contacts the end guide surface 11 of the column end 8a. At this time, the axial distance from the contact position P2 between the needle roller 2 and the column 8 to the root of the column 8 is short. Therefore, the position acting on the root of the column 8 ( Figure 6 The moment load at the position of corner R15 (as shown) is small.

[0087] like Figure 6 As shown, the shell-shaped needle roller bearing has a trapezoidal cross-sectional shape at the central portion 8c of the column, with the circumferential width gradually narrowing outwards. On both sides of the central portion 8c, there are press-faced surfaces 10. These press-faced surfaces 10 correspond to the hypotenuse of the trapezoid, thus... Figure 7 As shown, when the needle roller 2 contacts the central portion 8c of the column, it contacts the surface of the pressure surface 10, and not the radially outer corner portion of the circumferential side of the central portion 8c. Therefore, even when the position of the central portion 8c is moved closer to the radially inner side in order to reduce the circumferential clearance between adjacent needle rollers 2, it is possible to prevent the needle roller 2 from climbing onto the central portion 8c, and the needle roller 2 can be stably guided. Furthermore, as... Figure 7 As shown, the cross-sectional shape of the central part 8c of the column is a trapezoid with the circumferential width gradually narrowing towards the radial outward. Therefore, when the circumferential gap between adjacent needle rollers 2 is narrow, it is easy to obtain a larger circumferential width of the central part 8c of the column, which can easily ensure the strength of the retainer 3.

[0088] In addition, such as Figure 5 , Figure 6 As shown, a relief portion 12 is formed such that the circumferential side surface of the inclined portion 8b of the column is recessed circumferentially relative to the pressing surface 10. Therefore, when the mold with a trapezoidal cross-section is pressed onto the central portion 8c of the column to plastically process the central portion 8c into a trapezoidal cross-section, interference between the mold and the inclined portion 8b can be prevented, and the mold is made to contact only the central portion 8c of the column. Therefore, the pressing surface 10 (the surface corresponding to the hypotenuse of the trapezoid) of the central portion 8c of the column can be stably formed.

[0089] In addition, such as Figure 2As shown, a circumferential gap is formed between the avoidance portion 12 and the needle roller 2, which functions as a flow path of oil for lubricating the inside of the shell-shaped needle bearing, so that oil film breakage of the needle roller 2 can be prevented.

[0090] In addition, as shown in Figure 3 , the shell-shaped needle bearing is formed with the column end portion 8a in such a manner that the outer diameter dl of the column end portion 8a is larger than the outer diameter d3 of the column central portion 8c, and the inner diameter d2 of the column end portion 8a is smaller than the outer diameter d3 of the column central portion 8c, so that as shown in Figure 4 , the column central portion 8c and the column end portion 8a become a positional relationship of being coincident when viewed from the axial direction, and the shape of the column portion 8 becomes a shape in which the positional change in the radial direction is small along the axial direction. Therefore, as shown in Figure 7 , when the needle roller 2 contacts the column central portion 8c, a torsion force around the axial direction is less likely to be generated in the column portion 8, so that the durability of the retainer 3 can be improved.

[0091] In addition, for the shell-shaped needle bearing, as shown in Figure 9 , the end portion guide surface 11 that contacts the outer periphery of the needle roller 2 is formed in the column end portion 8a, so that as shown in Figure 10 , when the needle roller 2 contacts the column end portion 8a, the axial distance from the contact position P2 to the root of the column portion 8 (the corner R portion 15) is short. Therefore, the moment load that acts on the position of the root of the column portion 8 (the position of the corner R portion 15) due to the contact of the needle roller 2 can be suppressed, and the needle roller 2 can be guided.

[0092] In addition, for the shell-shaped needle bearing, as shown in Figure 5 , the corner R portion 15 is provided so as not to have a portion that is recessed in the circumferential direction with respect to the end portion guide surface 11, so that the rigidity of the root of the column portion 8 (the size of the circumferential width of the root of the column portion 8) can be ensured, and the stress concentration of the root of the column portion 8 can be moderated by the corner R portion 15.

[0093] In addition, for the shell-shaped needle bearing, Figure 7 , the surface roughness of the press surface processed surface 10 shown in Figure 8 is small, so that oil film breakage can be prevented when the needle bearing contacts the press surface processed surface 10. Therefore, even in the case where low viscosity oil is used as the oil for lubricating the inside of the shell-shaped needle bearing, the bearing life can be ensured.

[0094] In addition, for the shell-shaped needle bearing, as shown in Figure 5 , the press surface processed surface 10 is smoothly connected to the avoidance portion 12 via the convex circular arc-shaped central side R portion 13, and the end portion guide surface 11 is smoothly connected to the avoidance portion 12 via the convex circular arc-shaped end portion side R portion 14, so that oil film breakage can be prevented when the needle roller 2 contacts the press surface processed surface 10 or the end portion guide surface 11.

[0095] Further, for the shell type needle bearing, the distance from the radially inner end of one of the pair of column end portions 8a that are opposed in the circumferential direction across the needles 2 to the radially inner end of the other column end portion 8a is set to be 90% or more and 110% or less of the outer diameter of the needle 2, so the circumferential play between the end portion outer periphery of the needle 2 and the end portion guide surface 11 is small, and the skewing (inclination in the axial direction of the needle 2) of the needle 2 can be effectively prevented. Figure 7

[0096] In the above-described embodiment, a V-shaped retainer in which the circular ring portion 7 and the column portion 8 are V-shaped as viewed in the circumferential direction was described as an example of the retainer 3, but the present application can also be applied to an M-shaped retainer and a W-shaped retainer.

[0097] It should be considered that the embodiments disclosed herein are illustrative and not restrictive in all aspects. The scope of the present application is not the above description, but the scope of the present application as claimed, and is intended to include the meaning and scope equivalent to the scope of the present application and all modifications within the scope.​

Claims

1. A shell-type needle roller bearing, comprising: Shell-shaped outer ring (1); Multiple needle rollers (2) are arranged circumferentially spaced along the inner circumference of the outer shell ring (1); and Holder (3) maintains the circumferential spacing of the plurality of needle rollers (2). The retainer (3) has: a pair of annular portions (7) axially opposed across the needle rollers (2); and a plurality of column portions (8) passing between adjacent needle rollers (2) in the circumferential direction and connecting the pair of annular portions (7). Each column portion (8) has: a pair of column ends (8a) extending axially inward from the pair of annular portions (7) with a constant outer diameter (d1); a pair of column inclined portions (8b) extending obliquely such that the outer diameter gradually decreases from the pair of column ends (8a) toward the axially inward; and a column central portion (8c) connecting the pair of column inclined portions (8b). The shell-shaped needle roller bearing is characterized in that... A pressing surface (10) is formed on the circumferential sides of the central portion (8c) of the column, with the cross-sectional shape of the central portion (8c) being a trapezoid whose circumferential width gradually narrows towards the radially outward direction. The pressing surface (10) corresponds to the hypotenuse of the trapezoid and is formed as a contact surface with the outer periphery of the needle roller (2). A groove-shaped clearance portion (12) is provided on the circumferential sides of the inclined column portion (8b) in such a way that the sides are recessed in the circumferential direction relative to the pressing surface (10), and the clearance portion (12) extends radially on the circumferential sides of the inclined column portion (8b).

2. The shell-shaped needle roller bearing according to claim 1, characterized in that, The column end (8a) is formed such that the outer diameter (d1) of the column end (8a) is larger than the outer diameter (d3) of the column center (8c), and the inner diameter (d2) of the column end (8a) is smaller than the outer diameter (d3) of the column center (8c). End guide surfaces (11) are formed on the circumferential sides of the end of the column (8a). The end guide surfaces (11) extend perpendicularly to the circumferential direction in a manner that intersects the pressing surface (10) when viewed from the axial direction, and contact the outer periphery of the needle roller (2).

3. The shell-shaped needle roller bearing according to claim 2, characterized in that, A concave arc-shaped corner R (15) is formed between the end guide surface (11) and the side surface of the annular portion (7) on the axial inner side, so as to connect the two in such a way as not to produce a portion that is recessed in the circumferential direction relative to the end guide surface (11).

4. The shell-shaped needle roller bearing according to claim 2 or 3, characterized in that, The surface roughness of the pressed surface (10) is less than the surface roughness of the end guide surface (11).

5. The shell-shaped needle roller bearing according to claim 2 or 3, characterized in that, It has a convex arc-shaped central side R portion (13) that smoothly connects the pressed surface (10) and the clearance portion (12) when viewed radially, and a convex arc-shaped end side R portion (14) that smoothly connects the end guide surface (11) and the clearance portion (12).

6. The shell-shaped needle roller bearing according to claim 2 or 3, characterized in that, Viewed from the axial direction, the position where the end guide surface (11) intersects with the pressing surface (10) is within 90% of the radial outer end of the pressing surface (10).

7. The shell-type needle roller bearing according to any one of claims 1 to 3, characterized in that, The distance from the radial inner end of one of the two opposing column ends (8a) in the circumferential direction across the rollers (2) to the radial inner end of the other column end (8a), i.e. the shortest distance connected by a straight line, is set to be more than 90% and less than 110% of the outer diameter of the rollers (2).

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