JP2009162353A - Planetary gear mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high reliability in planetary gear mechanism having a long life. <P>SOLUTION: The planetary gear mechanism includes a sue gear, a ring gear, a pinion gear disposed between the ring gear and the sun gear, a planet carrier for holding a pinion shaft inserted into the pinion gear, and a needle roller bearing for supporting the pinion gear to the pinion shaft in a freely rotatable manner. The needle bearing is equipped with needle rollers and a retainer 13 with a pair of rings 14, pillars 15 coupling mutually the pair of the rings 14, and pockets 20 for housing the needle rollers between the adjacent pillars 15. The pillar 15 includes a pillar central portion 16, a pair of pillar ends 17, and a pair of pillar sloping portions 18 located among the pillar central portion 16 and the pair of pillar ends 17. The pillar central portion 16, the pair of the pillar ends 17 and the pair of the pillar sloping portions 18 are each thinner than each of adjacent boundary portions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a planetary gear mechanism, and more particularly to a planetary gear mechanism including a needle roller bearing.

  In general, a planetary gear mechanism is employed in an automatic transmission mounted on an automobile. As a bearing for supporting the pinion gear constituting the planetary gear mechanism, a cage and roller type needle roller bearing composed of a roller and a cage is often employed. Such a bearing is described in, for example, JP 2000-257638 A (Patent Document 1).

In this publication, a tubular material is formed into an annular member having an M-shaped cross section by bulging, and a roller retaining window is formed on the annular member, thereby obtaining a roller bearing retainer that is lightweight and has a large load capacity. It is stated that you can.
JP 2000-257638 A

  When the roller bearing retainer is formed by the method described in the above publication, the bent portion, that is, the boundary portion between the column central portion and the column inclined portion, the boundary portion between the column inclined portion and the column end portion, and the column end The thickness of the boundary portion between the portion and the annular side portion becomes thinner than the thickness of the tubular material. Since the stress acting on the cage during rotation of the bearing is concentrated on the bent portion, the risk of breakage of the roller bearing cage is increased by reducing the thickness of the bent portion.

  Further, when such a needle roller bearing is employed as a bearing for supporting the pinion gear constituting the planetary gear mechanism described above, the life and reliability of the planetary gear mechanism may be reduced.

  Accordingly, an object of the present invention is to provide a long-life and highly reliable planetary gear mechanism by employing a high-strength needle roller bearing.

  A planetary gear mechanism according to the present invention includes a sun gear having external teeth, a ring gear that has internal teeth, and is arranged on the outside of the sun gear so that the rotational axis coincides with the sun gear. A plurality of pinion gears arranged between the gear and the sun gear, a planet carrier holding a plurality of pinion shafts inserted through the plurality of pinion gears, and a needle-like shape that rotatably supports the pinion gears with respect to the pinion shafts Including roller bearings. The needle roller bearing accommodates needle rollers between a plurality of needle rollers, a pair of ring-shaped ring portions, a plurality of column portions interconnecting the pair of ring portions, and adjacent column portions. And a cage having a plurality of pockets. The column part is a column center part positioned relatively radially inward in the axial center region, a pair of column end parts positioned relatively radially outside in the axial end region, and a pair with the column center part. A pair of column inclined portions located between each of the column end portions. The thickness of each part of the column center part, the pair of column end parts, and the pair of column inclined parts is smaller than the thickness of the boundary part between adjacent parts.

  With the above configuration, the strength of the boundary portion of the cage is relatively improved. As a result, the risk of breakage of the cage due to stress concentration can be reduced. By adopting such a needle roller bearing as a bearing for supporting the pinion gear constituting the planetary gear mechanism, a planetary gear mechanism having a long life and high reliability can be obtained. In the present specification, “thickness” refers to the thickness dimension between the inner diameter surface and the outer diameter surface.

  Preferably, the thickness of each part of the column center part, the pair of column end parts, and the pair of column inclined parts is larger than the radius of curvature of the boundary part between adjacent parts. Thereby, the surface area of the part which contacts pinion gear etc. can be increased. As a result, the contact surface pressure can be reduced and wear and seizure can be prevented.

  Preferably, the cage expands both axial end portions of the cylindrical member having a diameter substantially equal to the central portion of the column to form a pair of column end portions, and compresses the cylindrical member in the axial direction. And a step of increasing the thickness of the boundary portion.

  Preferably, the wall surface facing the pocket of the column portion protrudes from each of the pair of column end portions and a first roller stopper portion that protrudes from the center portion of the column to prevent the needle rollers from coming out radially inward. A second roller stopper for preventing the needle roller from coming out radially outward is formed.

  As another embodiment, the cage further includes a flange portion extending radially inward from each of the pair of ring portions. And a pair of ring part and the thickness of a collar part are smaller than the thickness of the boundary part of a ring part and a collar part.

  According to the present invention, it is possible to obtain a high-strength roller bearing cage by making the boundary portion of the cage thicker than other portions. By adopting such a needle roller bearing as a bearing for supporting the pinion gear constituting the planetary gear mechanism, a planetary gear mechanism having a long life and high reliability can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 28 is a view showing an example of the planetary gear mechanism 101 according to one embodiment of the present invention. FIG. 29 is a cross-sectional view of the planetary gear mechanism 101 when cut by XXIX in FIG. First, the configuration of the planetary gear mechanism 101 will be described with reference to FIGS.

  The planetary gear mechanism 101 includes a sun gear 102, a ring gear 103, a plurality of pinion gears 104, a planet carrier 106, and a needle roller bearing 11.

  The sun gear 102 has external teeth and rotates integrally with the first rotation shaft 108.

  The ring gear 103 has internal teeth and is arranged outside the sun gear 102 so that the rotation axis coincides with the sun gear 102.

  The plurality of pinion gears 104 have external teeth and are arranged at equal intervals between the ring gear 103 and the sun gear 102. Then, it meshes with the sun gear 102 and the ring gear 103 and revolves around the sun gear 102 while rotating. A pinion shaft 107 is inserted through the center of each pinion gear 104. The needle roller bearing 11 is disposed between the pinion gear 104 and the pinion shaft 107 and supports the pinion gear 104 rotatably with respect to the pinion shaft 107.

  The planet carrier 106 holds a plurality of pinion shafts 107 inserted through the pinion gears 104. Therefore, when the planet carrier 106 rotates, each pinion gear 104 revolves. Similarly, when each pinion gear 104 revolves, the planet carrier 106 rotates. Further, the planet carrier 106 rotates integrally with the second rotation shaft 110.

  Next, the operation of the planetary gear mechanism 101 will be described. The planetary gear mechanism 101 fixes one of the sun gear 102, the ring gear 103, and the pinion gear 104, and inputs one of the remaining two gears as an input and the other as an output. The machine operates as a reverse device.

  When operating as a speed reducer, for example, the ring gear 103 is fixed, the sun gear 102 is input, and the planet carrier 106 is output. In this case, the first rotation shaft 108 is an input shaft, and the second rotation shaft 110 is an output shaft. The pinion gear 104 meshes with the sun gear 102 that rotates integrally with the first rotating shaft 108 and rotates, and meshes with the ring gear 103 to revolve around the sun gear 102. Then, the planet carrier 106 transmits the revolution movement of the pinion gear 104 to the second rotating shaft 110 as an output. At this time, the rotation of the second rotating shaft 110 is decelerated as compared with the first rotating shaft 108 and is converted to high torque. Even if the sun gear 102 is fixed, the ring gear 103 is input, and the planet carrier 106 is output, it operates as a speed reducer.

  When operating as a speed increaser, for example, the ring gear 103 is fixed, the planet carrier 106 is input, and the sun gear 102 is output. In this case, the second rotating shaft 110 is an input shaft, and the first rotating shaft 108 is an output shaft. The pinion gear 104 revolves around the sun gear 102 along with the rotation of the planet carrier 106 that rotates integrally with the second rotation shaft 110, and rotates in mesh with the ring gear 103. The sun gear 102 meshes with the pinion gear 104 and transmits the rotation of the pinion gear 104 to the first rotation shaft 108 as an output. At this time, the rotation of the first rotating shaft 108 is accelerated as compared with the second rotating shaft 110 and is converted to a low torque. Even if the sun gear 102 is fixed, the planet carrier 106 is input, and the ring gear 103 is output, the sun gear 102 operates as a speed increaser.

  Further, when operating as a reverse device, for example, by fixing the planet carrier 106, the sun gear 102 and the ring gear 103 are rotated in reverse. In this case, by operating either the first rotating shaft 108 or the second rotating shaft 110 as an input shaft and the other as an output shaft, it is possible to operate as a reverse device.

  Here, the needle roller bearing 11 and the roller bearing cage 13 (hereinafter simply referred to as “the cage 13”) will be described with reference to FIGS. 1 is a perspective view of the cage 13, FIG. 2 is a perspective view of the needle roller bearing 11, FIG. 3 is a perspective view showing the shape of the column portion 15 of the cage 13, and FIG. 4 is an arrow IV in FIG. It is an arrow view seen from the direction.

  First, referring to FIG. 2, the needle roller bearing 11 includes a plurality of needle rollers 12 and a cage 13 that holds the plurality of needle rollers 12. Next, referring to FIG. 1, the retainer 13 includes a pair of ring-shaped ring portions 14 and a plurality of column portions 15 that connect the pair of ring portions 14 to each other. A pocket 20 for accommodating the needle rollers 12 is formed between the adjacent column portions 15.

  In the present specification, the “annular ring portion” refers only to an integral ring portion that is continuous in the circumferential direction. That is, it should be understood that a ring portion in which both ends are joined by welding or the like is not included.

  The column portion 15 includes a column central portion 16 positioned relatively radially inward in the axial central region, a pair of column end portions 17 positioned relatively radially outward in the axial end region, and A column central portion 16 and a pair of column inclined portions 18 positioned between each of the column end portions 17 are included.

  Next, referring to FIG. 3 and FIG. 4, first and second roller stoppers 16 a and 17 a that prevent the needle rollers 12 from dropping off on the wall surface of the column portion 15 facing the pocket 20, and the needle Guide surfaces 16b, 17b, 18b for guiding the rotation of the tapered roller 12, non-contact portions 16c, 17c, and oil grooves 16d, 17d as concave portions are provided.

  The first roller stoppers 16 a are provided at two locations on the column central portion 16. More specifically, it is unevenly distributed radially inward of the wall surface of the column central portion 16 facing the pocket 20. Then, the needle rollers 12 are prevented from falling off inward in the radial direction.

  The second roller stopper 17a is provided at each of the pair of column end portions 17. More specifically, it is unevenly distributed on the radially outer side of the wall surface of the column end portion 17 facing the pocket 20. Then, the needle rollers 12 are prevented from falling off radially outward.

  With such first and second roller stoppers 16a and 17a, even if the needle roller 12 has a small diameter, the needle roller 12 retains the cage while ensuring a sufficient play amount of the needle roller 12. It is possible to effectively prevent the dropout from 13.

  The guide surface 16b is provided in the area | region adjacent to the 1st roller stop part 16a of the pillar center part 16 at an axial direction. The guide surface 17b is provided in a region adjacent to the second roller stopper 17a of the column end portion 17 in the axial direction. The guide surface 18 b is provided in the entire area of the column inclined portion 18. Further, the guide surfaces 16b, 17b, 18b constitute the same plane. Further, the guide surfaces 16b, 17b, 18b facing each other across the pocket 20 are parallel to each other. Thereby, the needle roller 12 can be rotated stably.

  The non-contact portions 16c and 17c are provided in regions adjacent to the first and second roller stoppers 16a and 17a in the radial direction. The non-contact portions 16c and 17c are retracted from the guide surfaces 16b, 17b and 18b, and face the needle rollers 12 with a predetermined gap. The non-contact portions 16c and 17c are inclined so that a predetermined gap increases as the distance from the first and second roller stoppers 16a and 17a increases in the radial direction.

  Specifically, the non-contact part 16c is provided in the area | region of the radial direction outer side of the 1st roller stopper part 16a, and inclines so that the clearance gap with the needle roller 12 may increase toward a radial direction outer side. . Similarly, the non-contact portion 17c is provided in the radially inner region of the second roller stopper 17a, and is inclined so that the gap with the needle roller 12 increases radially inward.

  As a result, the amount of lubricating oil flowing into the first and second roller stoppers 16a and 17a increases. As a result, the oil film breakage of the first and second roller stoppers 16a and 17a can be prevented.

  The oil grooves 16d and 17d are provided on both axial sides of the first and second roller stoppers 16a and 17a. The oil grooves 16d and 17d have a shape extending in the radial direction and are further retracted from the non-contact portions 16c and 17c. Thereby, the quantity of the lubricating oil which flows to radial direction can be increased, and the oil permeability of the radial direction of the holder | retainer 13 can be improved. Further, since the lubricating oil overflowing from the oil grooves 16d, 17d is supplied to the adjacent first and second roller stoppers 16a, 17a and the guide surfaces 16b, 17b, 18b, the first and second rollers Oil film breakage of the stoppers 16a, 17a, etc. can be prevented.

In the column portion 15 having the above-described configuration, the wall thickness t ₁ of the column central portion 16, the column end portion 17, and the column inclined portion 18 (hereinafter collectively referred to as “linear portion”) is set to be substantially equal. Yes. On the other hand, the thickness t ₂ of the boundary portion between the column central portion 16 and the column inclined portion 18 and the boundary portion between the column end portion 17 and the column inclined portion 18 (hereinafter collectively referred to as “boundary portion”) is It is thicker than the wall thickness t ₁ of the straight line portion (t ₁ <t ₂ ). Thereby, the intensity | strength of a boundary part improves relatively. As a result, it is possible to effectively prevent the cage 13 from being damaged even if stress during rotation of the bearing is concentrated on the boundary portion.

Further, the thickness t ₁ of the straight line portion and the curvature radius r of the boundary portion satisfy the relationship r <t ₁ . If the curvature radius r of the boundary portion is reduced, the axial length of the linear portion adjacent to the boundary portion can be increased, that is, the surface area of the linear portion can be increased. As a result, the contact surface pressure during rotation of the bearing can be reduced.

  Specifically, when the cage 13 is an outer diameter side guide (inner diameter surface guide of the pinion gear 104), the outer diameter surface of the column end portion 17 and the inner diameter surface of the pinion gear 104 are in contact with each other. Therefore, if at least the curvature radius r of the boundary portion between the column end portion 17 and the column inclined portion 18 is within the above range, the distance between the outer diameter surface of the column end portion 17 and the inner diameter surface of the pinion gear 104 is reduced. The contact surface pressure can be reduced.

  Further, the surface roughness Ra of the outer diameter surfaces of the ring portion 14 and the column end portion 17 is set to 0.05 μm or more and 0.3 μm or less. Thereby, wear due to contact between the outer diameter surfaces of the ring portion 14 and the column end portion 17 and the inner diameter surface of the pinion gear 104 can be prevented. “Surface roughness Ra” refers to arithmetic average roughness.

  On the other hand, when the cage 13 is an inner diameter side guide (outer diameter surface guide of the pinion shaft 107), the inner diameter surface of the column central portion 16 and the outer diameter surface of the pinion shaft 107 are in contact with each other. Therefore, if at least the curvature radius r of the boundary portion between the column central portion 16 and the column inclined portion 18 is within the above range, it is between the inner diameter surface of the column central portion 16 and the outer diameter surface of the pinion shaft 107. The contact surface pressure can be reduced. In this case, the surface roughness Ra of the inner diameter surface of the column central portion 16 may be set to 0.05 μm or more and 0.3 μm or less.

In addition, as for a boundary part, R part is formed in the convex side (side where tensile stress acts at the time of bending) and the concave side (side where compressive stress acts at the time of bending), respectively. At this time, the curvature radius on the convex side is always larger than the curvature radius on the concave side. Therefore, “the radius of curvature r of the boundary portion” in this specification refers to the radius of curvature on the convex side. Further, the “thickness t _{2 of the} boundary portion” refers to the length of a line segment connecting the central portion on the convex side and the central portion on the concave side.

  Further, the outer diameter surface of the column central portion 16 is located on the radially outer side than the inner diameter surface of the column end portion 17. The pitch circle 12 a of the needle roller 12 is located on the radially inner side from the outer diameter surface of the column central portion 16 and on the radially outer side from the inner diameter surface of the column end portion 17. Thereby, the needle roller 12 contacts each of the guide surfaces 16b, 17b, and 18b. Thus, the skew of the needle roller 12 can be effectively prevented by increasing the contact area between the needle roller 12 and the guide surfaces 16b, 17b, 18b.

  By using the needle roller bearing 11 having the above-described configuration as a bearing for supporting the pinion gear 104 constituting the planetary gear mechanism 101, the planetary gear mechanism 101 having a long life and high reliability can be obtained.

  However, the positional relationship between the column center portion 16 and the column end portion 17 is not limited to the above case. A modified example of the cage 13 will be described with reference to FIG. FIG. 5 is a view showing a modification of the cage 13 and corresponds to FIG. In addition, since the shape and function of each component are common, the same reference number is attached to the same component as FIG. 4, and description is abbreviate | omitted.

  Referring to FIG. 5, the outer diameter surface of the column center portion 16 is located on the radially inner side with respect to the inner diameter surface of the column end portion 17. The pitch circle 12 a of the needle roller 12 is located on the radially outer side from the outer diameter surface of the column center portion 16 and on the radially inner side from the inner diameter surface of the column end portion 17. In this case, the needle roller 12 is guided only on the guide surface 18 b of the column inclined portion 18. If it is set as the above-mentioned composition, since the 1st roller stop part 16a and the 2nd roller stop part 17a are arranged away in the diameter direction, drop-off of needle roller 12 can be prevented appropriately.

  Next, with reference to FIGS. 6-15, the manufacturing method of the holder | retainer 13 is demonstrated. 6 is a flowchart showing the main manufacturing process of the cage 13, FIGS. 7 to 10 are diagrams showing details of the first process, FIGS. 11 to 14 are diagrams showing details of the second process, FIG. 15 is a diagram showing details of the third step.

  First, as a starting material for the cage 13, a steel plate (carbon steel) having a carbon content of 0.15 wt% or more and 1.1 wt% or less is used. Specifically, SCM415 or S50C having a carbon content of 0.15 wt% or more and 0.5 wt% or less, or SAE1070 or SK5 having a carbon content of 0.5 wt% or more and 1.1 wt% or less.

  Carbon steel having a carbon content of less than 0.15 wt% is unlikely to have a carburized hardened layer formed by quenching, and needs to be carbonitrided to obtain the required hardness for the cage 13. The carbonitriding process increases the equipment cost compared to each quenching process described later, and as a result, the manufacturing cost of the needle roller bearing 11 increases. In addition, in carbon steel having a carbon content of less than 0.15 wt%, a sufficient carburized hardened layer may not be obtained even by carbonitriding, and surface-origin type peeling may occur early. On the other hand, the workability of carbon steel having a carbon content exceeding 1.1 wt% is significantly reduced.

  In the first step shown in FIG. 6, the cylindrical member 22 is obtained from the steel plate as the starting material (S11). Specifically, referring to FIG. 7, a cup-shaped member 21 is obtained from a steel plate by deep drawing. At this time, a bottom wall 21a is formed at one axial end portion (upper side in FIG. 7) of the cup-shaped member 21, and an outward flange portion 21b is formed at the other axial end portion (lower side in FIG. 7). The At this time, the surface roughness Ra of the outer diameter surface or inner diameter surface of the cup-shaped member 21 is set to 0.05 μm or more and 0.3 μm or less by ironing.

  Next, referring to FIG. 8, the bottom wall 21a of the cup-shaped member 21 is removed by punching. However, the bottom wall 21a cannot be completely removed by punching, and an inward flange portion 21c is formed at one end of the cup-shaped member 21 in the axial direction.

  Next, referring to FIG. 9, the inward flange portion 21c is raised in the axial direction by burring. Further, referring to FIG. 10, the outward flange portion 21b is removed by cutting the other axial end portion of the cup-shaped member 21 by trimming.

  Thereby, the cylindrical member 22 can be obtained. The outer diameter size of the cylindrical member 22 obtained in the above process matches the outer diameter size of the column central portion 16. In addition, the thickness of the cylindrical member 22 obtained in the above process is t.

  Next, in the second step shown in FIG. 6, the cylindrical member 22 is deformed in the radial direction to form the column central portion 16, the pair of column end portions 17, and the pair of column inclined portions 18 (S12). In this embodiment, an outer mold 23 for expanding press that restrains the outer diameter surface of the cylindrical member 22 (hereinafter simply referred to as “outer mold 23”) and a pair of expanding presses that restrain the inner diameter surface of the cylindrical member 22. Using the inner dies 25 and 26 (hereinafter, simply referred to as “inner dies 25 and 26”), both end portions in the axial direction of the cylindrical member 22 are expanded (expansion press).

  Referring to FIGS. 11 to 14, outer mold 23 has a cylindrical space 23 a that receives cylindrical member 22 therein. The cylindrical space 23a includes a small diameter portion 23b that matches the outer diameter size of the column center portion 16, a large diameter portion 23c that matches the outer diameter size of the column end portion 17, and the small diameter portion 23b and the large diameter portion 23c. It is comprised by the inclination part 23d which corresponds to the inclination angle of the column inclination part 18. As shown in FIG.

  The first inner mold 25 is a columnar member that is inserted from one axial end (upper side in FIG. 11) of the cylindrical member 22. The first inner mold 25 includes a small diameter portion 25a that matches the inner diameter size of the column center portion 16, a large diameter portion 25b that matches the inner diameter size of the column end portion 17, and the small diameter portion 25a and the large diameter portion 25b. It is comprised with the inclination part 25c which corresponds to the inclination angle of the column inclination part 18. FIG. The second inner mold 26 has the same configuration, and is inserted from the other axial end portion (lower side in FIG. 11) of the cylindrical member 22.

  The outer mold 23 includes, for example, first to fourth divided outer molds 24a, 24b, 24c, and 24d that are radially divided at intervals of 90 °. The first to fourth divided outer dies 24 a to 24 d can be moved in the radial direction of the cylindrical member 22 by a moving jig 27. The first and second inner dies 25 and 26 are movable in the axial direction of the cylindrical member 22, respectively.

  Referring to FIG. 11, when the first to fourth divided outer dies 24a to 24d are retracted in the radial direction and the first and second inner dies 25 and 26 are retracted in the axial direction, the cylindrical member 22 is moved into the cylindrical space. It will be in the state which can be taken in / out from 23a. Here, “retreat” refers to movement in a direction away from the cylindrical member 22.

  Next, referring to FIG. 13, when the first to fourth divided outer dies 24a to 24d advance in the radial direction, the outer diameter surface of the cylindrical member 22 is restrained by the small diameter portion 23b. Further, referring to FIG. 14, when the first and second inner dies 25, 26 are advanced in the axial direction, both end portions in the axial direction of the cylindrical member 22 have diameters due to the large diameter portions 25b, 26b and the inclined portions 25c, 26c. It is pushed outward in the direction. Here, “advance” refers to movement in a direction approaching the cylindrical member 22.

Thereby, the pillar center part 16, a pair of pillar edge part 17, and a pair of pillar inclination part 18 are each formed. Since the cylindrical member 22 is stretched by the expansion press, the wall thickness t ₁ of the column central portion 16, the pair of column end portions 17, and the pair of column inclined portions 18 after the completion of the second step is the cylindrical member 22. Is less than the wall thickness t (t ₁ <t).

  Next, in the third step shown in FIG. 6, the boundary portion is thickened by the thickening process (S13).

  Referring to FIG. 15, a pair of cylindrical compression jigs 28 and 29 are used for the thickening process. Specifically, in a state where the cylindrical member 22 is constrained by the outer mold 23 and the inner molds 25 and 26 (in a state where the expansion press is performed), both end surfaces in the axial direction of the cylindrical member 22 by the pair of compression jigs 28 and 29. Compress from both sides.

At this time, since the inner and outer diameter surfaces of the straight portion are constrained by the outer mold 23 and the inner molds 25 and 26, the wall thickness does not change. On the other hand, a minute gap is formed between the boundary portion and the outer mold 23 and the inner molds 25 and 26. Thereby, while the axial direction dimension of the cylindrical member 22 reduces, only a boundary part is thickened. The thickness t ₂ of the boundary portion after the third step is thicker than the thickness t of the cylindrical member 22 obtained in the first step (t ₁ <t <t ₂ ). Accordingly, the thickness of the column portion 15 is not increased overall to improve the strength, but the thickness of the straight portion is reduced, and the thickness of the boundary portion where stress concentration occurs is selectively increased. Improve strength. Therefore, the cage 13 can be reduced in weight. At this time, the radius of curvature r of the boundary portion is also smaller than the thickness t _{1 of the} straight portion.

  Next, in the fourth step shown in FIG. 6, the pocket 20 and the oil grooves 16d and 17d are formed in the cylindrical member 22 (S14). Specifically, a plurality of pockets 20 and oil grooves 16d and 17d are formed on the circumferential surface of the cylindrical member 22 by punching using a punch and a die. The punch is composed of a rectangular portion corresponding to the pocket 20 and a protruding portion corresponding to the oil grooves 16d and 17d protruding in the circumferential direction from the rectangular portion. Thus, by performing pocket punching on the cylindrical member 22, the guide surfaces 16b, 17b, 18b facing each other with the pocket 20 in between are parallel to each other.

  Next, the first and second roller stoppers 16a and 17a, the guide surfaces 16b, 17b and 18b, and the non-contact parts 16c and 17c are formed by ironing, respectively. With reference to FIG. 16 and FIG. 17, the case where the 1st roller stop part 16a is formed by ironing is demonstrated in detail. FIG. 16 is a diagram showing a state before ironing, and FIG. 17 is a diagram showing a state after ironing.

  First, referring to FIG. 16, for ironing, a punch 60 that is pushed into the pocket 20 from the outside in the radial direction of the cage 13, and processing tables 61 and 62 that support the cage 13 from the inside in the radial direction of the cage 13. And are used. The punch 60 includes a small width portion 60 a having a width smaller than the circumferential width dimension of the pocket 20 on the front end side, and a large portion 60 b having a width larger than the circumferential width dimension of the pocket 20 on the rear end side. The end face 60c of the large portion 60b is inclined so that the circumferential width dimension of the large portion 60b increases as the distance from the small width portion 60a increases in the radial direction. The processing bases 61 and 62 are disposed so that the end surfaces 61a and 62a face each other. At this time, the interval between the end faces 61 a and 62 a matches the width dimension of the small width portion 60 a of the punch 60.

The holder 13 is set between the punch 60 and the processing tables 61 and 62 having the above configuration. In this case, set to the respective wall surfaces of the column center part 16 facing each other across the pocket 20, to retract the end face 61a of the work table 61, from 62a by a width _{W 1.} Moreover, a substantial portion 60b of the punch 60 and the respective wall surfaces of the column center part 16 facing each other across the pocket 20, is set to overlap by a width W _2.

Next, referring to FIG. 17, the first roller stopper 16 a and the non-contact portion 16 c are formed by pushing the punch 60 into the pocket 20. Specifically, the radially outer region of the column center part 16, a non-contact portion 16c set back by the width W _2. The non-contact part 16c is formed in the shape inclined along the end surface 60c of the large part 60b. Further, the radially inner region of the column center portion 16 becomes the first roller stopper portion 16a protrudes by a width W _1.

  When the second roller stopper 17a and the non-contact portion 17c are formed, the punch 60 is set on the radially inner side of the cage 13 and the processing tables 61 and 62 are set on the radially outer side of the cage 13, respectively. That's fine.

  In this way, in the fourth step shown in FIG. 6, first, the pocket 20 and the oil grooves 16d and 17d are formed, and then the first and second roller stoppers 16a and 17a and the like are formed. Therefore, in order to form the oil grooves 16d and 17d first, when the punch 60 is pushed in by ironing to form the first and second roller stoppers 16a and 17a, the pushed-in portions are guided surfaces 16b and 17b. , 18b can be reduced.

  Next, in a fifth step shown in FIG. 6, heat treatment is performed to impart predetermined mechanical properties such as surface hardness to the cage 13 (S15). As the heat treatment, it is necessary to select an appropriate method depending on the carbon content of the starting material in order for the cage 13 to obtain a cured layer having a sufficient depth. Specifically, in the case of a material having a carbon content of 0.15 wt% or more and 0.5 wt% or less, carburizing and quenching treatment is performed, and in the case of a material having a carbon content of 0.5 wt% or more and 1.1 wt% or less. Performs bright quenching or induction quenching.

  The carburizing and quenching process is a heat treatment method utilizing the phenomenon that carbon dissolves in high-temperature steel, and a surface layer (carburized hardened layer) with a large amount of carbon can be obtained while the amount of carbon in the steel is low. . Thereby, the surface is hard, the inside is soft, and the property with high toughness is obtained. Moreover, the equipment cost is low compared with the carbonitriding equipment.

  The bright quenching process refers to a quenching process performed while preventing oxidation of the steel surface by heating in a protective atmosphere or vacuum. In addition, the equipment cost is low compared with carbonitriding equipment and carburizing and quenching equipment.

  Induction hardening is a method of making a hardened hardened layer by rapidly heating and rapidly cooling the steel surface using the principle of induction heating. Compared to other quenching treatment facilities, there is a merit that the equipment cost is significantly lower and that the gas is not used in the heat treatment process, so that it is environmentally friendly. It is also advantageous in that a partial quenching process can be performed.

  Furthermore, it is desirable to perform tempering after the above-mentioned quenching treatment in order to reduce residual stress and internal strain caused by quenching and to improve toughness and stabilize dimensions.

  The cage 13 can be obtained through the above steps. The surface roughness Ra of the outer diameter surface of the cage 13 is already 0.05 μm or more and 0.3 μm or less in the ironing process when the cylindrical member 22 is formed (S11). Therefore, an independent grinding process as a finishing process can be omitted.

  Here, in the conventional welded cage described in Japanese Patent No. 3665653, a pocket is formed in a belt-shaped plate material, a roller pawl is formed on a wall surface facing the pocket, and then the plate material is formed into an annular shape. To form a cage. In this case, there is a possibility that the cage breaks from the joint portion by welding or the like. However, in the present invention, the cage 13 is formed from the cylindrical member 22, so that the possibility of breakage can be reduced.

  In the above embodiment, an example in which the thicknesses of the column center portion 16 and the column end portion 17 are set to be substantially equal has been described. However, when it is desired to improve oil permeability in the axial direction, the column end portion The thickness of 17 may be made smaller than the thickness of the column center portion 16. By doing so, it is possible to increase the amount of lubricating oil flowing into the needle roller bearing 11 or exiting from the needle roller bearing 11. As a result, the oil permeability in the axial direction is improved. The improvement in oil permeability contributes to the removal of wear powder and the suppression of the temperature rise of the needle roller bearing 11.

  Further, in this case, the thickness of the column center portion 16 and the column end portion 17 can be adjusted by the shape of the mold used in the expanding press step (S12) shown in FIGS. Specifically, the distance between the large diameter portion 23c of the outer mold 23 and the large diameter portions 25b and 26b of the inner molds 25 and 26 is set so that the small diameter portion 23b of the outer mold 23 and the small diameter portions 25a and 26a of the inner molds 25 and 26 are reduced. Smaller than the interval. Then, the thickness of the column end portion 17 can be made smaller than the thickness of the column central portion 16 without adding a new process to the above-described manufacturing process of the cage 13.

  Moreover, in said embodiment, although the example of the expansion press (S12) was demonstrated as a method of forming the pillar center part 16, a pair of pillar edge part 17, and a pair of pillar inclination part 18, it is restricted to this. Without reducing the diameter, the central portion of the cylindrical member 22 in the axial direction may be reduced in diameter to form the column central portion 16, the pair of column end portions 17, and the pair of column inclined portions 18 (diameter reduction press). Specifically, in the cylindrical member 22 forming step (S <b> 11) shown in FIG. 6, the cylindrical member 22 whose diameter matches the outer diameter of the column end portion 17 is obtained. Referring to FIG. 11, first, when the first and second inner dies 25, 26 advance in the axial direction, the large diameter portions 25 b, 26 b restrain the inner diameter surface of the cylindrical member 22, and the small diameter portions 25 a, 25 a, A gap is formed between 26 a and the inner diameter surface of the cylindrical member 22. Next, when the first to fourth divided outer dies 24a to 24d advance in the radial direction, the central portion in the axial direction of the cylindrical member 22 is compressed inward in the radial direction by the small diameter portion 23b and the inclined portion 23d.

Thereby, the pillar center part 16, a pair of pillar edge part 17, and a pair of pillar inclination part 18 are each formed. Similarly, in this case, the thickness t ₁ of the column center portion 16, the pair of column end portions 17, and the pair of column inclined portions 18 after the second step is smaller than the thickness t of the cylindrical member 22. (T ₁ <t).

  Next, with reference to FIGS. 18-25, the holder | retainer 33 which concerns on other embodiment of this invention, and its manufacturing method are demonstrated. In addition, the same reference number as the retainer 13 is attached | subjected to a common component and description is abbreviate | omitted.

First, referring to FIG. 18 to FIG. 22, the retainer 33 further includes a pair of flanges 19 extending radially inward from each of the pair of ring portions 14. Note that the thickness of the ring portion 14 and the thickness of the flange portion 19 in the axial direction are set to be substantially equal to the thickness t ₁ of the other straight portions. Further, the thickness of the boundary portion between the ring portion 14 and the flange portion 19 is thick t ₂ is substantially equal to the settings of other boundary. Further, the curvature radius of the boundary portion between the ring portion 14 and the flange portion 19 is set to be substantially equal to the curvature radius r of the other boundary portion.

That is, t ₁ <t ₂ is also established in this embodiment. Thereby, in addition to the effect already demonstrated, the intensity | strength of the root part of the collar part 19 improves. In addition, r <t ₁ is also established. Thereby, since the surface area of the outer diameter surface of the ring part 14 increases, the contact surface pressure with the inner diameter surface of the pinion gear 104 can be further reduced when the retainer 33 is guided on the outer diameter side. In addition, since the other structure is common with the holder | retainer 13, description is abbreviate | omitted.

  Among the manufacturing steps of the cage 33 having the above configuration, the first step (S11), the second step (S12), the fourth step (S14), and the fifth step (S15) in FIG. 13 and is not described here. With reference to FIGS. 23 to 25, the process of increasing the thickness of the cage 33 (corresponding to S13 in FIG. 6) will be described.

  In this embodiment, the process of increasing the thickness of the boundary portion and the formation of the flange portion 19 (necking process) are performed simultaneously. More specifically, the collar portion 19 is formed through two stages of a pretreatment process and a posttreatment process. And the thickening process is performed simultaneously with the post-processing step.

  First, referring to FIG. 23, the pretreatment step is a step of bending both ends in the axial direction of the cylindrical member 42 to be the flange portion 19 inward with respect to the column end portion 17 by a predetermined angle (45 ° in this embodiment). A necking outer mold 43 (hereinafter simply referred to as “outer mold 43”), a necking inner mold 45 (hereinafter simply referred to as “inner mold 45”), and a pair of necking jigs 48 and 49. Done.

  The outer mold 43 has the same configuration as the outer mold 23 for the expansion press and restrains the outer diameter surface of the cylindrical member 42. However, the axial length is shorter than the outer mold 23 for the expansion press, and both axial end portions of the cylindrical member 42 serving as the flange portion 19 are not restrained.

  The inner mold 45 has a small diameter portion 45a that matches the inner diameter dimension of the column central portion 16 in the axial center region of the outer diameter surface, and a large diameter portion 45b that matches the inner diameter size of the column end portion 17 in the axial end region. An inclined portion 45c along the column inclined portion 18 between the small-diameter portion 45a and the large-diameter portion 45b, and a necking portion that defines a bending angle (45 °) of the flange portion 19 by pre-processing at corners at both axial ends. It is a cylindrical member containing 45d.

  Referring to FIG. 24, this inner mold 45 includes, for example, first to eighth divided inner molds 46a, 46b, 46c, 46d, 46e, 46f, 46g, and 46h that are radially divided at an angle of 45 °. Consists of. The first to eighth divided inner dies 46a to 46h are movable in the radial direction.

  Specifically, when the first to eighth divided inner dies 46 a to 46 h are retracted in the radial direction, the first to eighth divided inner dies 46 a to 46 h can be put in and out of the cylindrical member 42. On the other hand, when the first to eighth divided inner dies 46a to 46h are advanced in the radial direction, the inner diameter surface of the cylindrical member 42 can be restrained (state shown in FIG. 23). The divided inner dies 46 a to 46 h can be advanced by inserting the insertion jig 47.

  The necking jig 48 has a necking portion 48 a along the inclination angle (45 °) of the flange portion 19 in the pretreatment process at the tip, and is movable in the axial direction of the cylindrical member 42. The necking jig 49 has the same configuration. When the pair of necking jigs 48 and 49 are retracted in the axial direction, the cylindrical member 42 can be taken in and out of the cylindrical space. On the other hand, when the pair of necking jigs 48 and 49 are advanced in the axial direction, both ends in the axial direction of the cylindrical member 42 (portions indicated by broken lines in FIG. 23) can be bent inward by a predetermined angle (45 °). .

  Next, referring to FIG. 25, in the post-processing step, the flange portion 19 is bent at 90 ° with respect to the column end portion 17. The processing jigs in the post-processing step are necking outer dies 54a to 54d (only 54a and 54c are shown) and necking inner dies 56a to 56h (only 56a and 56e are shown) having the same configuration as that used in the pre-processing step. The insertion jig 57 and a pair of necking jigs 58 and 59 are used. However, the necking part is not provided in the part which faces the collar part 19 of the inner molds 56a to 56h for necking and the pair of necking jigs 58 and 59.

  In the post-processing step, the inner and outer diameter surfaces of the cylindrical member 42 are restrained in the same procedure as in the pre-processing step, and the collar portion 19 is compressed from the axial direction by the necking jigs 58 and 59. Thereby, the angle | corner which the pillar edge part 17 and the collar part 19 make becomes 90 degrees. Further, in this step, the boundary portion can be increased in thickness as in the third step (S13) shown in FIG.

  In the above embodiment, an example in which the cages 13 and 33 are manufactured using a steel plate (flat plate) as a starting material has been shown. However, the present invention is not limited thereto, and a cylindrical member such as a pipe material is manufactured as a starting material. You can also. In this case, the first step (S11) shown in FIG. 6 can be omitted.

  In the above embodiment, the example in which the first and second roller stoppers 16a, 17a and the like are formed by ironing has been described. However, the present invention is not limited to this, and the first and second roller stoppers 16a, 17a may be formed by caulking. FIG. 26 is a diagram showing a state in which the first roller stopper 16a is formed by caulking, and FIG. 27 is a diagram showing a state in which the second roller stopper 17a is formed by caulking.

  Referring to FIG. 26, the first roller stopper 16 a is formed by caulking a radially inner wall surface of the column central portion 16 with a caulking jig 63. Referring to FIG. 27, second roller stopper 17 a is formed by caulking the radially outer wall surfaces of the pair of column end portions 17 with caulking jig 63. In addition, when forming the 1st and 2nd roller stopper parts 16a and 17a by caulking, the non-contact parts 16c and 17c are not formed.

  In the above-described embodiment, examples of the cage roller type needle roller bearings 11 and 31 are shown. However, the present invention is also applied to a needle roller bearing further including an inner ring and / or an outer ring. It is possible. Moreover, although the example which employ | adopted the needle roller 12 as a rolling element was shown, not only this but a cylindrical roller and a rod-shaped roller may be sufficient.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The planetary gear mechanism according to the present invention is effectively used when a long life is required.

It is a perspective view which shows the roller bearing retainer which concerns on one Embodiment of this invention. It is a perspective view which shows the needle roller bearing which employ | adopted the cage for roller bearings of FIG. It is a perspective view which shows the structure of the pocket of the cage for roller bearings of FIG. FIG. 4 is an arrow view seen from an arrow IV in FIG. 3. FIG. 5 is a modified example of the roller bearing retainer shown in FIG. 1, corresponding to FIG. 4. It is a flowchart which shows the main manufacturing processes of the cage for roller bearings shown in FIG. It is a figure which shows a deep drawing process. It is a figure which shows a punching process. It is a figure which shows a burring process. It is a figure which shows a trimming process. It is a figure which shows the state before the process of an expansion press process. It is the figure which looked at the outer type | mold for expansion presses from the axial direction. It is a figure which shows the state in the middle of the process of an expansion press process. It is a figure which shows the state after a process of an expansion press process. It is a figure which shows a thickening process. It is a figure which shows the state before ironing processing. It is a figure which shows the state after an ironing process. It is a perspective view which shows the cage for roller bearings concerning other embodiment of this invention. It is a perspective view which shows the needle roller bearing which employ | adopted the roller bearing retainer of FIG. It is a perspective view which shows the structure of the pocket of the cage for roller bearings of FIG. It is the arrow line view seen from the arrow XXI of FIG. FIG. 22 is a modified example of the roller bearing retainer shown in FIG. 18 and corresponds to FIG. 21. It is a figure which shows a pre-processing process. It is the figure which looked at the inner mold for necking from the axial direction. It is a figure which shows a post-processing process. It is a figure which shows the state which formed the 1st roller stop part by the crimping process. It is a figure which shows the state which formed the 2nd roller stop part by caulking. It is a figure which shows an example of the planetary gear mechanism which concerns on one Embodiment of this invention. It is sectional drawing of the planetary gear mechanism at the time of cut | disconnecting by XXIX of FIG.

Explanation of symbols

  11, 31 Needle roller bearing, 12 Needle roller, 12a Pitch circle, 13, 33 Cage, 14 Ring part, 15 Column part, 16 Column center part, 17 Column end part, 18 Column inclined part, 16a, 17a Roller Stopping part, 16b, 17b, 18b Guide surface, 16c, 17c Non-contact part, 16d, 17d Oil groove, 19 collar part, 20 pocket, 21 Cup-shaped member, 21a Bottom wall, 21b Outward flange part, 21c Inward flange Part, 22, 42 cylindrical member, 23, 43 outer mold, 23a cylindrical space, 23b, 25a, 26a, 45a small diameter part, 23c, 25b, 26b, 45b large diameter part, 23d, 25c, 26c, 45c inclined part, 24a 24b, 24c, 24d, 44a, 44b, 44c, 44d, 54a, 54c Divided outer mold, 25, 26, 45 Inner mold, 46a, 46b, 6c, 46d, 46e, 46f, 46g, 46h, 56a, 56e Divided inner mold, 27 Moving jig, 28, 29 Compression jig, 47, 57 Inserting jig, 48, 49, 58, 59 Necking jig, 45d , 48a, 49a Necking part, 60 punch, 60a narrow part, 60b large part, 61, 62 processing base, 60c, 61a, 62a end face, 63 caulking jig, 101 planetary gear mechanism, 102 sun gear, 103 ring gear, 104 Pinion gear, 106 planet carrier, 107 pinion shaft, 108 first rotating shaft, 110 second rotating shaft.

Claims (5)

Sun gear with external teeth;
A ring gear having internal teeth and disposed on the outside of the sun gear such that the rotational axis coincides with the sun gear;
A plurality of pinion gears having external teeth and disposed between the ring gear and the sun gear;
A planet carrier holding a plurality of pinion shafts inserted through the plurality of pinion gears;
A planetary gear mechanism including a needle roller bearing that rotatably supports the pinion gear with respect to the pinion shaft;
The needle roller bearing includes a plurality of needle rollers, a pair of ring-shaped ring portions, a plurality of column portions interconnecting the pair of ring portions, and the needle-like shape between adjacent column portions. A cage having a plurality of pockets for accommodating rollers,
The column portion is a column center portion that is relatively radially inward in the axial center region, a pair of column end portions that are relatively radially outward in the axial end region, and the column center portion And a pair of column inclined portions located between each of the pair of column end portions,
A planetary gear mechanism in which the thickness of each portion of the column central portion, the pair of column end portions, and the pair of column inclined portions is smaller than the thickness of a boundary portion between adjacent portions.   2. The planetary gear mechanism according to claim 1, wherein a thickness of each portion of the column center portion, the pair of column end portions, and the pair of column inclined portions is larger than a radius of curvature of a boundary portion between adjacent portions. The retainer is a step of expanding the diameter of both ends in the axial direction of a cylindrical member having a diameter substantially equal to the center of the column to form the pair of column ends,
The planetary gear mechanism according to claim 1, wherein the planetary gear mechanism is manufactured by a manufacturing method including a step of compressing the cylindrical member in an axial direction and increasing the thickness of the boundary portion.   A wall surface facing the pocket of the pillar part includes a first roller stopper that protrudes from the center part of the pillar and prevents the needle rollers from coming out radially inward, and a pair of pillar end parts, respectively. The planetary gear mechanism according to any one of claims 1 to 3, wherein a second roller stopper that protrudes and prevents the needle rollers from coming out radially outward is formed. The retainer further includes a flange portion extending radially inward from each of the pair of ring portions,
The planetary gear mechanism according to any one of claims 1 to 4, wherein a thickness of the pair of ring portions and the flange portion is smaller than a thickness of a boundary portion between the ring portion and the flange portion.

Images