JP2019173901A - Bearing and speed reducer - Google Patents

Abstract

To provide a structure of a bearing which can be manufactured easily, while suppressing deviation or slip of a fixing lubricant.SOLUTION: A bearing includes: a cylindrical inner ring 10; a plurality of rollers 13 arranged along an outer peripheral surface of the inner ring; and a first cage 11 arranged radially outside of the inner ring, and for holding the rollers at an outer peripheral part of the inner ring. The first cage includes: a plurality of first column parts 110 extending in the axial direction; a first ring 111 for connecting end parts of an upper part in the axial direction of the plurality of first column parts; and at least one protrusion part 113 protruding radially inside from the first ring. The inner ring and the first cage rotate relatively with each other. The plurality of rollers are arranged between the adjacent first column parts respectively. Part of the rollers are located further radially outside than the first column parts. Between the first ring and the inner ring, and between the first colum part and the inner ring, a second cage 12 is arranged. The second cage is made of a fixing lubricant, is formed by a single member, and at least part of it is located on the lower side of the protrusion part 113.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a bearing and a reduction gear.

  2. Description of the Related Art Conventionally, a technique that uses a solid lubricant in a rolling bearing using rolling elements such as rollers (hereinafter simply referred to as a bearing) is known. Since the solid lubricant is held inside the bearing, the lubricity of the roller is maintained, and fatigue of the bearing due to friction is suppressed. For this reason, a technique for holding the solid lubricant in contact with the roller stably for a long time inside the bearing is important for extending the life of the bearing. The method for filling the bearing with the solid lubricant is described in, for example, Japanese Patent Application Laid-Open Nos. 2004-257491 and 2017-15206.

  Japanese Patent Application Laid-Open No. 2004-257491 discloses a method of manufacturing an assembly molded body in which a roller, a solid lubricant, and a cage in which the roller is disposed at a predetermined position are integrated using a molding die. ing. The molding die includes an outer die, an inner die, a hollow portion formed between the outer die and the inner die, and a middle die fitted to the inner die in the hollow portion. The thermal expansion coefficient of the middle mold is larger than that of the outer mold and the inner mold. When manufacturing an assembly molded body, first, a cage in which a roller is disposed is inserted into the hollow portion, and a solid lubricant is filled in a gap between the roller and the cage. Then, the temperature of the molding die is increased to greatly expand the middle die, and the fixed lubricant is press-molded against the roller held by the cage, thereby solidifying and molding the assembly molded body.

Japanese Patent Application Laid-Open No. 2017-15206 discloses a method of providing a first cage for holding a roller at an outer peripheral portion of an inner ring of a bearing and further inserting a second cage made of a solid lubricant between the inner ring and the first cage. Is disclosed. Thereby, by bringing the solid lubricant into contact with the roller, the lubricity of the roller can be maintained even during the operation of the bearing. Moreover, the work efficiency at the time of manufacturing a bearing improves by making solid lubricant into parts as a 2nd cage.
JP 2004-257491 A JP 2017-015206 A

  However, the manufacturing method described in Japanese Patent Application Laid-Open No. 2004-257491 requires a lot of man-hours and time for manufacturing a bearing including heat treatment. In the structure described in Japanese Patent Application Laid-Open No. 2017-15206, two bearings are arranged facing each other. As a result, the second cage is prevented from shifting or coming out of the space between the inner ring and the first cage. However, when a single bearing or an odd number of bearings are used side by side, a structure for preventing the second cage from shifting or coming off between the inner ring and the first cage is separately required.

  An object of the present invention is to provide a bearing structure that can be easily manufactured while suppressing the displacement or slippage of a fixed lubricant.

  An exemplary first invention of the present application is a bearing, which is a cylindrical inner ring having a central axis extending vertically, a plurality of rollers disposed along an outer peripheral surface of the inner ring, and a diameter of the inner ring. A first cage that is disposed on an outer side in the direction and holds the roller on an outer peripheral portion of the inner ring, wherein the first cage includes a plurality of first column portions extending in an axial direction, and the first column portion. A first ring that connects axially upper ends, and at least one protrusion that protrudes radially inward from the first ring, the inner ring and the first cage rotate relative to each other; The plurality of rollers are respectively disposed between the adjacent first pillar portions, and a part of the rollers is located radially outside of the first pillar portion, and the first ring and the inner ring And a second cage disposed between the first pillar portion and the inner ring. Is, the second cage is made of a solid lubricant is formed from a single member, and at least partially positioned on the lower side of the projecting portion.

  According to the first exemplary invention of the present application, the first cage has a protrusion that protrudes radially inward from the first ring. And the 2nd cage which is a solid lubricant which consists of a single member at least one part is located under the said projection part. Thereby, the shift | offset | difference or omission of a fixed lubricant can be suppressed using a simple structure.

FIG. 1 is a longitudinal sectional view of the speed reducer. FIG. 2 is a cross-sectional view of the speed reducer. FIG. 3 is a cross-sectional view of the bearing. FIG. 4 is an exploded perspective view of the bearing. FIG. 5 is a partial longitudinal sectional view of the bearing. FIG. 6 is a partial bottom view of the first cage. FIG. 7 is a longitudinal sectional view of the first cage. FIG. 8 is a flowchart for manufacturing the bearing. FIG. 9 is a longitudinal sectional view of a first cage according to a modification.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the present application, the direction parallel to the central axis (the rotation axis and the first central axis described later) is the “axial direction”, the direction orthogonal to the central axis is the “radial direction”, and the direction is along the arc centered on the central axis. Are referred to as “circumferential direction”, respectively. However, the above “parallel direction” includes a substantially parallel direction. In addition, the above-mentioned “orthogonal direction” includes a substantially orthogonal direction. In the following, for convenience of explanation, the right side of FIG. 1 is referred to as “axially upward”, and the left side of FIG. 1 is referred to as “axially downward”. However, this definition of the vertical direction is not intended to limit the direction of use of the bearing and the speed reducer according to the present invention.

<1. First Embodiment>
<1-1. Overall structure of reduction gear>
FIG. 1 is a longitudinal sectional view of a reduction gear 2 including a bearing 1 according to a first embodiment of the present invention, cut along a plane including a rotating shaft 90. FIG. 2 is a cross-sectional view of the speed reducer 2 viewed from the position AA in FIG.

  The speed reducer 2 is an inscribed planetary speed reducer that converts the rotational motion at the first rotational speed into the rotational motion at the second rotational speed lower than the first rotational speed, that is, reduces the rotational speed. The speed reducer 2 is used by being incorporated in a drive mechanism such as a robot, a machine tool, an XY table, a material cutting device, a conveyor line, a turntable, a rolling roller, or the like. However, the speed reducer of the present invention may be used for other purposes.

  As shown in FIG. 1, the speed reducer 2 of the present embodiment includes an input rotator 20, a speed reduction mechanism 30, and an output rotator 40. The bearing 1 according to the present embodiment is included in the speed reduction mechanism 30.

  The input rotator 20 is a member that rotates at a first rotation speed that is a rotation speed input from the outside. In the present embodiment, a cylindrical member disposed along the rotation shaft 90 is the input rotator 20. The axially upper end of the input rotator 20 is connected to a motor (not shown) as a drive source directly or via another power transmission mechanism. When the motor is driven, the input rotator 20 rotates at the first rotation speed around the rotation shaft 90.

  The input rotator 20 has an eccentric portion 21. The eccentric portion 21 has a cylindrical outer peripheral surface centering around a first central axis 91 extending vertically and parallel to the rotational shaft 90 at a position deviated from the rotational shaft 90. When the input rotator 20 rotates, the position of the first central axis 91 also rotates around the rotational axis 90.

  The deceleration mechanism 30 is a mechanism that is interposed between the input rotator 20 and the output rotator 40 and transmits the rotational motion of the input rotator 20 to the output rotator 40 while decelerating. The speed reduction mechanism 30 according to the present embodiment includes an external gear 31, a frame 33, and the bearing 1.

  The bearing 1 is attached to the outer peripheral portion of the eccentric portion 21. The external gear 31 is attached to the outside of the bearing 1 in the radial direction via a roller 13. Therefore, the external gear 31 is supported rotatably about the first central axis 91 of the eccentric portion 21.

  As shown in FIG. 2 in an enlarged manner, the external gear 31 has a plurality of external teeth 51 protruding outward in the radial direction on the outer peripheral portion thereof. In addition, an inter-external tooth groove 52 that is recessed inward in the radial direction is provided between adjacent external teeth 51. The external teeth 51 and the inter-external teeth grooves 52 are alternately arranged in the circumferential direction around the first central axis 91.

  As shown in FIGS. 1 and 2, the external gear 31 has a plurality of (eight in the example of FIG. 2) insertion holes 53. The plurality of insertion holes 53 are arranged at equal intervals in the circumferential direction around the first central axis 91. Each insertion hole 53 penetrates the external gear 31 in the axial direction on the radially inner side of the external teeth 51 and the inter-external tooth grooves 52.

  In addition, although the speed reduction mechanism 30 of this embodiment has the one external gear 31, the number of the external gear 31 may be two or more. The number of external gears 31 may be an even number or an odd number.

  The frame 33 is a substantially cylindrical member that accommodates the input rotator 20, the output rotator 40, the bearing 1, and the external gear 31 therein. As shown in an enlarged manner in FIG. 2, the frame 33 has a plurality of internal teeth 61 projecting radially inward on the inner peripheral portion thereof. Further, between the adjacent internal teeth 61, an internal inter-tooth groove 62 that is recessed outward in the radial direction is provided. The internal teeth 61 and the internal inter-tooth grooves 62 are alternately arranged in the circumferential direction around the rotation shaft 90.

  The plurality of external teeth 51 of the external gear 31 and the plurality of internal teeth 61 of the frame 33 mesh with each other. That is, during the operation of the speed reducer 2, the external teeth 51 of the external gear 31 are fitted in the internal gear grooves 62 of the frame 33, and the internal teeth 61 of the frame 33 are fitted in the external gear grooves 52 of the external gear 31. However, the external gear 31 rotates. Thus, in this embodiment, the frame 33 functions as an internal gear. However, apart from the frame 33, an internal gear may be provided as a separate member on the inner peripheral portion of the frame 33.

  The external gear 31 rotates by meshing with the internal teeth 61 of the frame 33 while revolving around the rotation shaft 90 by the power of the input rotating body 20. Here, the number of internal teeth 61 included in the frame 33 is larger than the number of external teeth 51 included in the external gear 31. For this reason, for each revolution of the external gear 31, the position of the external teeth 51 that mesh with the internal teeth 61 at the same position of the frame 33 shifts. As a result, the external gear 31 slowly rotates in the direction opposite to the rotation direction of the input rotating body 20 at the second rotation speed lower than the first rotation speed. Therefore, the position of the insertion hole 53 of the external gear 31 also rotates slowly at the second rotational speed.

  When the number of external teeth 51 of the external gear 31 is N and the number of internal teeth 61 of the frame 33 is M, the reduction ratio P of the reduction mechanism 30 is P = (first rotation speed) / (second Rotational speed) = N / (MN). In the example of FIG. 2, since N = 59 and M = 60, the reduction ratio P of the reduction mechanism 30 in this example is P = 59. That is, the second rotation speed is 1/59 of the first rotation speed. However, the reduction ratio P of the speed reduction mechanism 30 in the present invention may be another value.

  The output rotating body 40 rotates around the rotating shaft 90 at the second rotation speed after deceleration. As shown in FIG. 1, the output rotating body 40 of the present embodiment includes a first disk body 41, a second disk body 42, and a plurality (eight in this embodiment) of pins 43.

  The first disc body 41 is an annular member disposed perpendicular to the rotation shaft 90. The first disc body 41 is disposed below the external gear 31 in the axial direction. Ball bearings 70 are interposed between the first disk body 41 and the input rotating body 20 and between the first disk body 41 and the frame 33, respectively. Thereby, the first disc body 41 is supported so as to be relatively rotatable with respect to the frame 33 and the input rotating body 20.

  The first disc body 41 is provided with a plurality (eight in this embodiment) of press-fit holes 311 for press-fitting a plurality of pins 43. The plurality of press-fit holes 311 are arranged at equal intervals in the circumferential direction around the rotation shaft 90. Each press-fit hole 311 penetrates the first disc body 41 in the axial direction.

  The second disc body 42 is an annular member disposed perpendicular to the rotation shaft 90. The second disc body 42 is disposed above the external gear 31 in the axial direction. Ball bearings 70 are interposed between the second disk body 42 and the input rotating body 20 and between the second disk body 42 and the frame 33, respectively. Thus, the second disk body 42 is supported so as to be relatively rotatable with respect to the frame 33 and the input rotating body 20.

  The second disc body 42 is provided with a plurality (eight in this embodiment) of fixing holes 321 for inserting axially upper ends of the plurality of pins 43. The plurality of fixing holes 321 are arranged at equal intervals in the circumferential direction around the rotation shaft 90. Each fixing hole 321 passes through the second disc body 42 in the axial direction.

  The plurality of pins 43 are cylindrical members that connect the first disk body 41 and the second disk body 42. Each pin 43 is disposed substantially parallel to the rotation shaft 90. Further, the plurality of pins 43 are respectively inserted into the plurality of insertion holes 53 of the external gear 31. The plurality of pins 43 are respectively press-fitted into the plurality of press-fit holes 311 of the first disc body 41. Further, a flange portion 331 having an enlarged diameter is provided at an end portion in the axial direction of each pin 43. The upper surface of the flange portion 331 is in contact with the first disc body 41 in the axial direction. As a result, the pins 43 are prevented from slipping upward in the axial direction. Further, the axially upper end portion of each pin 43 is inserted into the fixing hole 321 of the second disc body 42 and is fixed to the second disc body 42 with a nut.

  As shown in FIG. 2, a gap is interposed between the surface constituting each insertion hole 53 and the outer peripheral surface of the pin 43. An annular bush ring 71 is inserted into the gap. When the external gear 31 rotates at the second rotational speed after deceleration, the power is transmitted to each pin 43 via the bush ring 71. As a result, the plurality of pins 43, the first disk body 41, and the second disk body 42 rotate at the second rotation speed around the rotation shaft 90.

<1-2. Bearing structure>
Next, the structure of the bearing 1 will be described. FIG. 3 is a cross-sectional view of the bearing 1. FIG. 4 is an exploded perspective view of the bearing 1. FIG. 5 is a partial vertical sectional view of a part of the bearing 1 in the circumferential direction. However, in FIG. 5 and FIG. 1 described above, a protrusion 113, an upper recess 122, a first taper 141, and a second taper 142, which will be described later, are shown larger than other parts. As shown in FIGS. 3 to 5, the bearing 1 includes an inner ring 10, a first cage 11, a second cage 12, and a plurality of rollers 13.

  The inner ring 10 is disposed on the outer periphery of the input rotating body 20. The inner ring 10 is a cylindrical member centered on the first central axis 91. When the input rotator 20 rotates, the inner ring 10 rotates about the rotation axis 90 of the input rotator 20. The inner ring 10 includes a groove 102 that is recessed in an annular shape along the circumferential direction on the outer peripheral surface. The plurality of rollers 13 are arranged along the groove portion 102 on the outer peripheral surface of the inner ring 10. For this reason, the plurality of rollers 13 are restricted from moving in the axial direction at the outer peripheral portion of the inner ring 10. The plurality of rollers 13 are in contact with the inner peripheral surface of the external gear 31. In addition, although the number of the rollers 13 which the bearing 1 has is 19 in this embodiment, other numbers may be sufficient.

  The first cage 11 is a molded product obtained by molding a resin. The first cage 11 is molded, for example, by injecting a substantially liquid resin into the mold and performing a heat treatment. The first cage 11 is disposed on the radially outer side of the inner ring 10 and rotates relative to the inner ring 10 around the first central axis 91. In the present embodiment, the first cage 11 includes a plurality of first pillar portions 110, a first ring 111, a second ring 112, and a plurality of protruding portions 113.

  The plurality of first pillar portions 110 extend in the axial direction on the radially outer side of the inner ring 10. Further, the plurality of first pillar portions 110 are arranged at equal intervals in the circumferential direction. End portions in the axial direction of the plurality of first pillar portions 110 are connected by an annular first ring 111. The plurality of rollers 13 are respectively disposed between the adjacent first pillar portions 110. Further, a part of the roller 13 is located on the outer side in the radial direction than the first column part 110. For this reason, the plurality of rollers 13 are held by the plurality of first pillar portions 110 at the outer peripheral portion of the inner ring 10, and the circumferential movement at the outer peripheral portion of the inner ring 10 is restricted. In addition, although the number of the 1st pillar parts 110 is 19 in this embodiment, other numbers than 19 may be sufficient.

  Further, the axially lower ends of the plurality of first pillar portions 110 are connected by an annular second ring 112. Thereby, the structure of the 1st cage 11 is strengthened. The inner diameter of the first ring 111 is larger than the inner diameter of the second ring 112 and the outer diameter of the second ring 112.

  FIG. 6 is a partial bottom view of the first cage 11. FIG. 7 is a longitudinal sectional view of the first cage 11. As shown in FIGS. 4 to 7, the first cage 11 is provided with a plurality (five in this embodiment) of protrusions 113. Each protrusion 113 protrudes radially inward from the first ring 111. However, the distance from the first central shaft 91 to the radially inner end of each protrusion 113 is larger than the outer diameter of the second ring 112. In addition, the protrusion part 113 should just be provided with at least 1 and the number is not limited. In the present embodiment, the plurality of protrusions 113 are provided at positions that do not overlap the first pillar 110 in the axial direction. Thereby, the 1st cage 11 can be manufactured only with a pair of metal mold | die opened and closed in an axial direction. In the present embodiment, the plurality of protrusions 113 are provided at unequal intervals in the circumferential direction. However, the plurality of protrusions 113 may be provided at equal intervals in the circumferential direction. Moreover, the protrusion part which protrudes over the perimeter in the circumferential direction may be provided in the radial inside from the 1st ring 111.

  As shown in FIGS. 3 to 5, the second cage 12 is disposed between the first ring 111 and the inner ring 10 and between the first pillar 110 and the inner ring 10. The second cage 12 is a single member made of a solid lubricant. The plurality of rollers 13 are held by the first cage 11 and the second cage 12 on the outer periphery of the inner ring 10. For this reason, the plurality of rollers 13 are in contact with the second cage 12, that is, the solid lubricant. Accordingly, the plurality of rollers 13 can smoothly roll on the outer peripheral portion of the inner ring 10. Therefore, friction accompanying the rolling of the roller 13 can be suppressed. Further, by using the solid lubricant, it is possible to prevent the lubricant from leaking to the outside of the bearing 1. Thereby, the lubricity of the roller 13 at the time of operation | movement of the bearing 1 is maintained for a long time, and the reliability of the reduction gear 2 can be improved.

  The second cage 12 is a molded product obtained by molding a solid lubricant. The second cage 12 is molded, for example, by injecting a substantially liquid lubricant into the mold and performing a heat treatment. Thus, by making the solid lubricant into a part as the second cage 12, the working time can be shortened when the bearing 1 is manufactured. Moreover, since firing of the solid lubricant is not necessary, the number of steps is reduced, and the manufacturing cost of the bearing 1 can be reduced.

  In the present embodiment, the second cage 12 includes an annular part 121 and a plurality of second pillar parts 120 extending from the annular part 121 in the axial direction. The annular portion 121 has an annular shape, and at least a part thereof is disposed between the first ring 111 and the inner ring 10. Further, the plurality of second pillar portions 120 are disposed between the first pillar portion 110 and the inner ring 10. Thus, if it is made the shape which has the cyclic | annular part 121 only in one side of the axial direction of the some 2nd pillar part 120, the metal mold | die which shape | molds the 2nd cage 12 can be comprised easily. Thereby, the manufacturing cost of the bearing 1 can further be reduced.

  The second cage 12 is inserted between the first cage 11 and the inner ring 10 from the axial direction. Further, the axial width of the annular portion 121 is preferably larger than the axial width of the first ring 111. Thereby, the roller 13 becomes easy to contact a solid lubricant. Note that the number of the second pillar portions 120 is 19 in the present embodiment, but may be a number other than 19 as long as it is equal to the number of the first pillar portions 110.

  The annular portion 121 of the second cage 12 is provided with a plurality of upper recessed portions 122 that are recessed from the upper surface to the lower side. The plurality of upper concave portions 122 are provided at circumferential positions corresponding to the plurality of protruding portions 113 of the first cage 11 in the vicinity of the outer peripheral portion of the upper surface of the annular portion 121. When the second cage 12 is disposed between the first cage 11 and the inner ring 10, the plurality of protrusions 113 are fitted into the plurality of upper recesses 122, respectively. Then, at least a part of the second cage 12 is located below the protrusion 113. Thereby, it is suppressed that the 2nd cage 12 shifts to the upper side of the 1st cage 11, or slips out in the axial direction. Further, the circumferential displacement of the second cage 12 with respect to the first cage 11 is suppressed. As a result, the lubricity of the roller 13 during operation of the bearing 1 is maintained for a long time, and the reliability of the speed reducer 2 can be further improved. Note that at least one upper recess 122 may be provided, and the number is not limited. Further, the number of the upper recesses 122 is not necessarily equal to the number of the protrusions 113.

  Further, the outer diameter of the annular portion 121 of the second cage 12 of this embodiment is larger than the inner diameter of the second ring 112 of the first cage 11. For this reason, when the second cage 12 is inserted between the first cage 11 and the inner ring 10 from the axial direction, the distal end portion (lower end portion) of the second column portion 120 contacts the second ring 112. Thereby, the front-end | tip part (lower end part) of the 2nd cage 12 is positioned to an axial direction. Further, the second cage 12 is prevented from being axially displaced or removed from the lower side of the first cage 11. As a result, the lubricity of the roller 13 during the operation of the bearing 1 is maintained for a longer period, and the reliability of the speed reducer 2 can be further increased.

  Moreover, the 1st inclined surface 114 which inclines upward as it goes to radial direction inner side is formed in the lower surface of the some protrusion part 113 of this embodiment, respectively. Moreover, the 2nd inclined surface 123 which inclines to the upper side is each formed in the site | part which faces the some upper side recessed part 122 among the upper surfaces of the 2nd cage 12, and goes to radial direction inner side, respectively. Accordingly, when the second cage 12 is inserted in the axial direction, the first inclined surfaces 114 of the plurality of protruding portions 113 are guided along the second inclined surfaces 123 of the plurality of upper concave portions 122, while The plurality of protrusions 113 can be fitted into the recesses 122 more smoothly. The first inclined surface 114 can be formed when the corner portion of the protruding portion 113 is tapered in the manufacturing process of the first cage 11. However, the first inclined surface 114 and the second inclined surface 123 are not necessarily provided. That is, the axial position on the lower surface of the protrusion 113 and the axial position near the outer peripheral portion of the upper surface of the annular portion 121 may be constant.

  In the present embodiment, a part of the second ring 112, a part of the annular part 121, and a part of the roller 13 overlap in the axial direction. That is, the plurality of rollers 13 are sandwiched between the second ring 112 and the annular portion 121 in the axial direction. In this way, even if the inner ring 10 has no groove 102, the axial positions of the first cage 11, the second cage 12, and the roller 13 are mutually regulated. Accordingly, the axial displacement of the roller 13 can be prevented without depending on the groove 102. Further, the second ring 112 has a lower recess 115 that forms a gap in the radial direction between the second ring 112 and the first pillar 110. And the front-end | tip part (lower end part) of the 2nd pillar part 120 fits in the lower side recessed part 115. FIG. Then, a part of the first pillar part 110, a part of the second pillar part 120, and a part of the second ring 112 overlap in the radial direction. As a result, the second cage 12 can be prevented from falling radially inward due to the rotational friction of the roller 13.

  Note that the lower concave portion 115 has a first taper portion 141 in which the radial width of the gap becomes narrower as it goes downward in the axial direction. Moreover, the front-end | tip part (lower end part) of the 2nd pillar part 120 has the 2nd taper part 142 whose radial direction width | variety becomes narrow as it goes to an axial direction downward direction. As a result, the second cage 12 is more securely held between the first cage 11 and the inner ring 10. Further, the circumferential displacement of the second cage 12 with respect to the first cage 11 is further suppressed.

  FIG. 8 is a diagram illustrating an example of a manufacturing flow of the bearing 1 according to the present embodiment. When manufacturing the bearing 1, first, a substantially liquid lubricant is injected into the mold. Then, the lubricant is solidified by heat-treating the mold (S1). Thereby, the 2nd cage 12 which consists of solid lubricants is fabricated (S2). Subsequently, the first cage 11 is attached to the inner ring 10 (S3), and the second cage 12 is inserted between the inner ring 10 and the first cage 11 (S4). Thereafter, the roller 13 is attached between the adjacent first pillar portions 110 (S5). By doing so, the step of filling the solid lubricant into the bearing 1 and the step of solidifying the solid lubricant by firing the bearing 1 become unnecessary. Thereby, the manufacturing man-hour of the bearing 1 can be reduced and the manufacturing cost of the bearing 1 can be reduced. The heat treatment includes firing and cooling.

<2. Modification>
As mentioned above, although exemplary embodiment of this invention was described, this invention is not limited to said embodiment.

  FIG. 9 is a longitudinal sectional view of a first cage 11B according to a modification. In the example of FIG. 9, a plurality of projections 116B (the same number as the projections 113B) that protrude upward from the upper surface of the first ring 111B are formed. And the some protrusion part 113B protrudes in the radial direction inner side from the convex part 116B, respectively. When the second cage is disposed between the first cage 11B and the inner ring, the plurality of protrusions 113B come into contact with the upper surface of the second cage 12, respectively. If it does so, at least one part of a 2nd cage will be located under the protrusion part 113B similarly to said embodiment. As a result, the second cage is prevented from being axially displaced or removed upward from the first cage 11B. As a result, the lubricity of the roller during the operation of the bearing is maintained for a long time, and the reliability of the reduction gear can be further increased.

  For example, a high-strength metal may be used as the material of each member other than the first cage and the second cage constituting the speed reducer. However, the material of each member should just be able to endure the load at the time of use, and is not necessarily limited to a metal.

  In the above embodiment, the first cage is molded by injecting a substantially liquid resin into the mold and performing a heat treatment. However, the first cage may be formed by other methods such as machining.

  Moreover, in said embodiment, the material which comprises a 1st cage was resin. However, the first cage only needs to be able to withstand the load during the bearing operation, and may be composed of other materials such as a metal material.

  Moreover, in the said embodiment, the 1st pillar part which the 1st cage has, the 1st ring, the 2nd ring, and the some projection part were fabricated as one member. However, the first pillar portion, the first ring, the second ring, and the plurality of protruding portions may be assembled as separate members.

  Moreover, in the said embodiment, the inner ring | wheel was equipped with the groove part dented in an annular shape along the circumferential direction on the outer peripheral surface. However, the groove is not necessarily provided. In this case, what is necessary is just to hold | maintain a some roller in the outer peripheral part of an inner ring | wheel with the some 1st pillar part which a 1st cage has, a 1st ring, and a 2nd ring.

  In the above embodiment, the second cage is molded by injecting a substantially liquid lubricant into the mold and performing a heat treatment. However, the second cage may be molded by other methods such as machining. In this case, the solid lubricant that has been heat-cured in advance may be processed into a shape including an annular portion and a second pillar portion.

  Moreover, in the said embodiment, the bearing was manufactured in order of S1 to S5. However, the bearing does not necessarily have to be manufactured in this order. For example, the order of the step of inserting the second cage between the inner ring and the first cage (S4) and the step of attaching the roller between the adjacent first pillars (S5) may be switched. . By doing so, the inner ring, the first cage, and the roller can be assembled in advance. And a bearing can be manufactured by inserting the 2nd cage shape | molded previously between an inner ring | wheel and a 1st cage as needed.

  Moreover, about the detailed shape of a reduction gear or a bearing, you may differ from the shape shown by each figure of this application. Moreover, you may combine suitably each element which appeared in said embodiment and modification in the range which does not produce inconsistency.

  The present invention can be used for bearings and reducers.

DESCRIPTION OF SYMBOLS 1 Bearing 2 Reduction gear 10 Inner ring | wheel 11,11B 1st cage 12 2nd cage 13 Roller
DESCRIPTION OF SYMBOLS 20 Input rotary body 21 Eccentric part 30 Deceleration mechanism 31 External gear 33 Frame 40 Output rotary body 41 1st disc body 42 2nd disc body 43 Pin 51 External tooth 52 Inter-tooth groove 53 Insertion hole 61 Internal tooth 62 In Interdental groove 70 Ball bearing 71 Bush ring 90 Rotating shaft 91 First central axis 102 Groove 110 First pillar 111, 111B First ring 112 Second ring 113, 113B Protruding part 114 First inclined surface 115 Lower concave part 116B Convex Part 120 Second column part 121 Annular part 122 Upper concave part 123 Second inclined surface 141 First taper part 142 Second taper part 311 Press-fit hole 321 Fixing hole 331 Flange part

Claims (14)

A cylindrical inner ring centered on a central axis extending vertically;
A plurality of rollers disposed along an outer peripheral surface of the inner ring;
A first cage that is disposed radially outside the inner ring and holds the roller on an outer periphery of the inner ring;
Have
The first cage is
A plurality of first pillars extending in the axial direction;
A first ring that connects axially upper ends of the plurality of first pillar portions;
At least one protrusion projecting radially inward from the first ring;
With
The inner ring and the first cage rotate relative to each other,
The plurality of rollers are respectively disposed between the adjacent first pillar portions,
A part of the roller is located on a radially outer side than the first column part,
A second cage is disposed between the first ring and the inner ring and between the first pillar portion and the inner ring,
The bearing, wherein the second cage is made of a solid lubricant, is formed from a single member, and is at least partially located below the protrusion. The bearing according to claim 1,
The first cage includes a plurality of the protrusions,
The plurality of protrusions are bearings provided at equal intervals in the circumferential direction. The bearing according to claim 1,
The first cage includes a plurality of the protrusions,
The plurality of protrusions are bearings provided at unequal intervals in the circumferential direction. The bearing according to any one of claims 1 to 3, wherein
The second cage has at least one upper recess that is a recess recessed downward from the upper surface;
The protrusion is a bearing that fits into the upper recess. The bearing according to any one of claims 1 to 3, wherein
The protrusion is a bearing that contacts an upper surface of the second cage. The bearing according to any one of claims 1 to 5,
The protruding portion is a bearing that does not overlap the first pillar portion in the axial direction. The bearing according to any one of claims 1 to 6,
The lower surface of the protrusion has a first inclined surface that is inclined upward as it goes radially inward. The bearing according to any one of claims 1 to 6,
A bearing in which the axial position of the lower surface of the protrusion is constant. The bearing according to any one of claims 1 to 8,
The second cage is a bearing which is a molded product obtained by molding the solid lubricant. The bearing according to any one of claims 1 to 9,
The second cage is
An annular part,
A plurality of second pillar portions extending in the axial direction from the annular portion;
Have
The annular portion is disposed between the first ring and the inner ring,
The second pillar part is a bearing disposed between the first pillar part and the inner ring. The bearing according to claim 10,
The first cage is
A second ring connecting the axially lower ends of the plurality of first pillar portions;
The inner diameter of the first ring is larger than the inner diameter of the second ring,
A bearing in which a tip end portion of the second pillar portion contacts the second ring. The bearing according to claim 11,
A bearing in which an inner diameter of the first ring is larger than an outer diameter of the second ring. The bearing according to any one of claims 1 to 12,
A bearing having a distance from the central axis to the radially inner end of the protrusion is larger than the outer diameter of the second ring. A speed reducer for reducing the rotational speed,
A speed reducer comprising the bearing according to any one of claims 1 to 13.

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