STOCK

Abstract

Bearing (100) comprising: an inner ring housing (2); an outer ring housing (1) arranged around the inner ring housing (2); a plurality of first rollers (10) designed to roll between an outer circumference of the inner ring housing (2) and an inner circumference of the outer ring housing (1); and a plurality of second rollers (11) arranged between adjacent first rollers (10), each of the second rollers (11) having a smaller diameter than each of the first rollers (10) and a longer axial length along an axis of rotation than each of the first rollers (10), the outer ring housing (1) having an annular guide groove (30), the guide groove (30) accommodating one end of each of the plurality of second rollers (11), with the axis of rotation of each of the second rollers (11) perpendicular to a radial and circumferential direction of the bearing (100), a groove width (Δr),the length of the guide groove (30) along the radial direction of the bearing (100) is greater than the diameter of each of the second rollers (11), and a first radius (r1) representing a distance from a bearing axis (O) to an inner wall surface of the guide groove (30) that is on the outside in the radial direction of the bearing (100) is less than a distance from the bearing axis (O) to an axial center (O1) of the first roller (10) plus a radius (b) of the second roller (11), wherein the radius (b) of the second roller (11) is greater than a first value of the radius (b) of the second roller (11) that is fixed such that the first rollers (10) are in contact with each other and the second roller (11) is in contact with adjacent first rollers (10), wherein the radius (b) of the second roller (11) is less than a second value of the radius (b) of the second roller (11) that is fixed such that is that a roller (10) originates from the axial center (O1),The triangle formed at the axial center of the second roller (11) adjacent to the first roller (10) and the bearing axis (O) is a right-angled triangle.

Description

Area The present disclosure relates to a bearing that uses two types of rollers with different diameters. background A proposed bearing utilizes two types of rollers with different diameters, thereby eliminating a cage to hold the rollers. A plurality of the larger-diameter rollers described in patent literature 1 are cylindrical rollers positioned between an inner ring element and a radially outer ring element. Smaller-diameter rollers, which are corrugated or shaft-shaped, are smaller in diameter than the larger-diameter rollers and are positioned between them. An annular groove in the radially outer ring element allows the smaller-diameter rollers to move radially. CITATION LIST Patent literature Patent Literature 1: Japanese Patent Application Disclosure Document JP 2000 - 55 044 A Brief description Technical problem Patent literature 1 provides no disclosure regarding the radial position and radial width of the groove in which the smaller diameter rollers are arranged, and the smaller diameter rollers in the groove can move to a gap on a radially outer side of the center positions of the larger diameter rollers. Therefore, there are concerns about damage to the larger diameter rollers due to increased rolling resistance from contact between them. Furthermore, the smaller diameter rollers can collide with an inner wall of the groove that is radially outer and can therefore be damaged or broken. The present disclosure was made in consideration of the foregoing, and it is an object of the present disclosure to provide a bearing which can prevent the smaller diameter rollers from moving at a radially outer gap over the axial centers of the larger diameter rollers, thereby preventing damage to the smaller diameter and larger diameter rollers and enabling a reduction in power losses. Solution to the problem To solve the problems mentioned above and to achieve the task, a bearing according to a first aspect comprises an inner ring housing; an outer ring housing arranged around the inner ring housing; a plurality of first rollers designed to roll between an outer circumference of the inner ring housing and an inner circumference of the outer ring housing; and a plurality of second rollers each arranged between adjacent first rollers, each of the second rollers being smaller in diameter than each of the first rollers and having a longer axial length along an axis of rotation than each of the first rollers, the outer ring housing having an annular guide groove, the guide groove accommodating one end of each of the plurality of second rollers, with the axis of rotation of each of the second rollers perpendicular to a radial direction and a circumferential direction of the bearing, a groove width,which represents a length of the guide groove along the radial direction of the bearing, greater than a diameter of each of the second rollers, and a first radius, representing a distance from a bearing axis to an inner wall surface of the guide groove, which is outside in the radial direction of the bearing, less than a distance from the bearing axis to an axial center of the first roller plus a radius of the second roller, wherein the radius of the second roller is greater than a first value of the radius of the second roller, which is determined such that the first rollers are in contact with each other and the second roller is in contact with adjacent first rollers, wherein the radius of the second roller is less than a second value of the radius of the second roller, which is determined such that a triangle formed by the axial center of the first roller, an axial center of the second roller adjacent to the first roller and the bearing axis is a right-angled triangle.According to a second aspect, a bearing comprises an inner ring housing; an outer ring housing arranged around the inner ring housing; a plurality of first rollers designed to roll between an outer circumference of the inner ring housing and an inner circumference of the outer ring housing; and a plurality of second rollers arranged between adjacent first rollers, each of the second rollers being smaller in diameter than each of the first rollers and having a longer axial length along an axis of rotation than each of the first rollers, the outer ring housing having an annular guide groove, the guide groove accommodating one end of each of the plurality of second rollers, with the axis of rotation of each of the second rollers perpendicular to a radial and circumferential direction of the bearing, and a groove width representing a length of the guide groove along the radial direction of the bearing.greater than a diameter of each of the second rollers, and a first radius representing a distance from a bearing axis to an inner wall surface of the guide groove, which is outside in the radial direction of the bearing, less than a distance from the bearing axis to an axial center of the first roller plus a radius of the second roller, wherein the guide groove accommodates only one of the plurality of ends of each of the second rollers. According to a third aspect, a bearing comprises an inner ring housing; an outer ring housing arranged around the inner ring housing; a plurality of first rollers designed to roll between an outer circumference of the inner ring housing and an inner circumference of the outer ring housing; and a plurality of second rollers each arranged between adjacent first rollers, each of the second rollers being smaller in diameter than each of the first rollers and having a longer axial length along an axis of rotation than each of the first rollers, the outer ring housing having an annular guide groove, the guide groove accommodating one end of each of the plurality of second rollers, with the axis of rotation of each of the second rollers perpendicular to a radial and circumferential direction of the bearing, and a groove width representing a length of the guide groove along the radial direction of the bearing.greater than a diameter of each of the second rollers, and a first radius, representing a distance from a bearing axis to an inner wall surface of the guide groove, which is outside in the radial direction of the bearing, is less than a distance from the bearing axis to an axial center (O1) of the first roller plus a radius of the second roller, wherein, if a radius of each of the second rollers is "b", the radius "b" satisfies the following formula: where "a" is a radius of each of the first rollers, L is a distance between a contact point where the first rollers touch each other and the bearing axis, R2 is a distance from the bearing axis to an outer circumference of the inner ring housing, H is a distance between an outer circumference of the inner ring housing and an inner circumference of the guide groove, and "n" is a number of second rollers. Advantageous effects of the invention According to the present disclosure, it is possible to prevent the second rollers from entering a radially outer gap beyond the axial centers of the first rollers. Therefore, damage to the first and second rollers can be avoided, and power loss due to contact between the first rollers can be reduced. Brief description of drawings Fig. 1 shows a front view of a bearing according to a first embodiment. Fig. 2 shows a cross-section of the bearing according to the first embodiment. Fig. 3 shows a diagram showing a section along line III-III in Fig. 2. Fig. 4 shows a diagram showing a section along line IV-IV in Fig. 2. Fig. 5 shows a diagram showing a section along line VV in Fig. 1. Fig. 6 shows a diagram showing where radii of parts of the bearing according to the first embodiment are arranged. Fig. 7 shows a diagram showing a state in which inner rollers are in contact with rollers during high-speed rotation of the bearing according to the first embodiment. Fig. 8 shows a diagram showing a roller having a further shape. Fig. 9 shows a diagram showing an inner roller having a further shape. Fig. 10 shows a sectional view of a bearing according to a second embodiment.Figure 11 shows a sectional view of a bearing according to a third embodiment. Figure 12 shows a diagram used to describe a bearing according to a fourth embodiment. Figure 13 shows a diagram used to describe the bearing according to the fourth embodiment. Figure 14 shows a diagram representing a bearing according to a fifth embodiment. Figure 15 shows a diagram representing a bearing according to the fifth embodiment. Figure 16 shows a diagram representing a bearing according to the fifth embodiment. Figure 17 shows a diagram representing a bearing according to the fifth embodiment. Figure 18 shows a diagram representing a bearing according to the fifth embodiment. Figure 19 shows a diagram representing a bearing according to the fifth embodiment. Description of embodiments With reference to the drawings, a detailed description of bearings according to the embodiments is provided below. It should be noted that these embodiments are not limiting to the present disclosure. First embodiment. Using Figures 1, 2, 3, 4, 5, 6 to 7, a description of a bearing according to a first embodiment is provided. Figure 1 shows a front view of the bearing according to the first embodiment. Fig. 2 shows a cross-section of the bearing depicted in Fig. 1, in a plane perpendicular to a bearing axis O, representing a state of rotation at a lower speed. Fig. 3 shows a diagram representing a section along line III-III of Fig. 2. Fig. 4 shows a diagram representing a section along line IV-IV of Fig. 2. Fig. 5 shows a diagram representing a section along line VV of Fig. 1. Fig. 6 shows a diagram illustrating the radii of parts. Fig. 7 shows a cross-section of the bearing depicted in Fig. 1, in a plane perpendicular to the bearing axis O, representing a high-speed rotational state. The bearing 100 in Figs. 1, 2, 3, 4 to 5 comprises: an outer ring housing 1; an inner ring housing 2 arranged on the inside of the outer ring housing 1; a plurality of rollers 10 as rollers with a larger diameter and a plurality of inner rollers 11 which are smaller in diameter than the rollers 10. Each of the rollers 10 has a radius “a”. Each of the inner rollers 11 has a radius “b” and a > b. The rollers 10 correspond to the first rollers in the claims, and the inner rollers 11 correspond to the second rollers in the claims. As shown in Figures 2 and 3, each of the plurality of rollers 10 has a cylindrical shape with an axis of rotation parallel to the bearing axis O at its center. As shown in Figures 2 and 4, each of the inner rollers 11 has a cylindrical shape with an axis of rotation parallel to the bearing axis O at its center. The axial length of each inner roller 11 along the axis of rotation is longer than the axial length of each roller 10 along the axis of rotation. The inner rollers 11 are rod-shaped. Each inner roller 11 is arranged between the adjacent rollers 10. The outer ring housing 1 is ring-shaped and has an interior space for accommodating the majority of rollers 10 and the majority of inner rollers 11. The inner ring housing 2 is also ring-shaped. As shown in Figs. 3, 4 to 5, the outer ring housing 1 has an annular guide groove 20 which accommodates some of the rollers 10. The guide groove 20 is a recess that is directed outwards in a radial direction of the bearing 100. An arc 21 in Figs. 2 and 6 corresponds to a position of a bottom 20a of the guide groove 20, as shown in Fig. 3. As shown in Fig. 6, the arc 21 has a radius R1 extending from the bearing axis O. An arc 22 corresponds to a position of an outer circumference 2d of the inner ring housing 2. As shown in Fig. 6, the arc 22 has a radius R2 extending from the bearing axis O. The rollers 10 are in contact with the bottom 20a of the guide groove 20 (i.e., the arc 21) and the outer circumference 2d of the inner ring housing 2 (i.e., the arc 22). In other words, the radius R2 plus a diameter 2×a of the roller 10 equals the radius R1. Each roller 10 rotates on its axis of rotation with its outer circumferential surface in contact with the arcs 21 and 22. Each roller 10 revolves around the bearing axis O with its outer circumferential surface in contact with the arcs 21 and 22. As shown in Figs. 3, 4, and 5, the outer ring housing 1 has a pair of annular guide grooves 30 as secondary guide grooves, which accommodate the axial ends 11a and 11b of each of the plurality of inner rollers 11. The guide grooves 30 are recesses along the bearing axis O. In Figs. 2 and 6, arc 31 corresponds to a position of the inner wall surfaces of the guide grooves 30 on the outer circumferential side. As shown in Fig. 6, arc 31 has a radius r1 extending from the bearing axis O. Arc 32 corresponds to a position of the inner wall surfaces of the guide grooves 30 on the inner circumferential side. As shown in Fig. 6, arc 32 has a radius r2 extending from the bearing axis O. The arc 31 is hereby referred to as an outer circumference of the guide grooves 30 and the arc 32 is hereby referred to as an inner circumference of the guide grooves 30. As shown in Fig. 6, each of the guide grooves 30 has a radial groove width Δr, which is equal to the radius r1 minus the radius r2. The groove width Δr of each guide groove 30 is larger than the diameter (2xb) of the inner roller 11. In other words, the radius r2 plus the diameter (2xb) of the inner roller 11 is smaller than the radius r1. For this reason, the inner rollers 11 are radially movable in the guide grooves 30. A detailed description is provided here of the positions of the outer circumference 31 and the inner circumference 32 of the guide grooves 30. The radius r1, which is a position of the outer circumference 31 of the guide grooves 30, is fixed to a value less than a distance r3 (see Fig. 6), which is a distance from the bearing axis O to an axial center O1 of the roller 10, plus the radius “b” of the inner roller 11. The distance r3 is equal to the radius R2 plus the radius “a” of the roller 10. In other words, the outer circumference 31 of the guide grooves 30 restricts the movement of the inner rollers 11 so that an axial center of the inner roller 11 cannot be in a radially outer position compared to the axial center O1 of the roller 10. This restriction by the outer circumference 31, unlike in patent literature 1, prevents the inner roller 11 from entering a radially outer gap beyond the axial center O1 of the roller 10. 10 beyond. The radius r2, which is the position of the inner circumference 32 of the guide grooves 30, is set to a value smaller than the radius r1 minus the diameter 2×b of the inner roller 11, in order to arrange a radially inner position. r1 is the position of the outer circumference 31 of the guide grooves 30. Furthermore, the radius r2, which is the position of the inner circumference 32 of the guide grooves 30, is set to a value greater than the radius r1 minus a distance “q” (see Fig. 3). The distance “q” is a distance between r1 and 1d, which is an outer surface of the outer ring housing 1 closer to the inner ring housing 2. This means that the radius r2 is set to a position further out on the circumferential side than 1d. As shown in Figures 1 and 5, the outer ring housing 1 has a threaded bore 40 that is connected to the guide groove 30. The inner rollers 11 can be inserted through the threaded bore 40. After the inner rollers 11 have been inserted through the threaded bore 40 during manufacturing, a screw 41 is inserted into the threaded bore 40 to close it. The threaded bore 40 in Figure 5 has a tapered section into which the head of the screw 41 fits. It should be noted, however, that the screw 41 has a defined length and that one end of the screw 41 has a defined shape, surface roughness, and flatness. This is to prevent the inserted screw 41 from forming a step where it would come into contact with the guide groove 30 and collide with the inner rollers 11. The threaded hole 40 in Fig.Threaded bore 40 is provided only on one side of the outer ring housing 1; however, the threaded bore 40 can be formed on either side of the outer ring housing 1. Alternatively, multiple intermittent threaded bores can be formed along one circumference of the outer ring housing 1. With the threaded bore 40, which is used to insert the inner rollers 11, and the screw 41 in the outer ring housing 1, the bearing 100 is easy to assemble. A description of how the bearing 100 operates was given next. As shown in Fig. 7, when the inner ring housing 2 rotates, each roller 10 rotates about its own axis. Each roller 10 revolves with the outer ring housing 1 to minimize rolling resistance. Each inner roller 11, in contact with the rollers 10, rotates about its own axis in a direction opposite to that of the rollers 10 and revolves in a circumferential direction relative to each roller 10 that has a greater mass. In a non-rotating state or during low-speed rotation, as shown in Fig. 2, each inner roller 11 is in contact with: the inner circumference 32 or the outer circumference 31 of the guide grooves 30 according to gravity; and with the roller 10 on each side. On the other hand, during high-speed rotation, a centrifugal force K acts on each inner roller 11, as shown in Fig. 7. Here, to minimize energy loss, the rollers 10 and the inner rollers 11 operate in a state where each inner roller 11 is in contact only with its neighboring rollers 10 and where all the inner rollers 11 rotate equidistantly from the bearing axis O. Therefore, during high-speed rotation, each inner roller 11 rotates on its own axis and circles while in contact only with its neighboring rollers 10 and not with the outer circumference 31 and the inner circumference 32 of the guide grooves 30.A bearing with an inner diameter of approximately 70 mm, such as a railway vehicle bearing, rotates at higher speeds than described above for most of its operating time. For example, if, as in the railway vehicle bearing, the inner diameter is 70 mm, the inner ring housing 2 has a thickness of 7.75 mm, an outer diameter of 125 mm, and each roller 10 has a diameter of 12 mm and a length of 15 mm, the inner rollers 11 move radially outward at an orbital speed of 15.14 rad / s or more, which is 2,410 rpm (144.58 RPM) or more, due to centrifugal force. The inner rollers 11 move at the same orbital speed as the rollers 10. Therefore, the orbital speed of the inner rollers 11 will be 144.58 rpm when a motor rotates at a speed of 1076.5 rpm or more.Because the maximum rotational speed of a rail motor ranges from 3500 rpm to approximately 4000 rpm, and for Shinkansen bullet trains reaches 5000 rpm to 6500 rpm, each inner roller 11 can obviously be in a state of contact with only the rollers 10, because the centrifugal force acts on each inner roller 11. While the rollers 10 and the inner rollers 11 are cylindrical in the preceding description, the rollers 10 can be spherical, as shown in Fig. 8. Fig. 8 shows a section along line III-III in Fig. 2. As shown in Fig. 9, each inner roller 11 can have the form of a rod with a neck, such that a central portion is smaller in diameter than each end of the rod. Fig. 9 shows a section along line IV-IV in Fig. 2. According to the first embodiment described above, the outer circumference 31 of the guide grooves 30 restricts the movement of the inner rollers 11 to prevent the axial center of each inner roller 11, which is radially aligned with the axial center O1 of the roller 10, from moving into the radially outer position. This prevents, unlike in patent literature 1, each inner roller 11 from extending into the radially outer space beyond the axial center O1 of the roller 10. Therefore, damage to the rollers 10 and the inner rollers 11 is avoided, and power loss due to contact between the rollers 10 is reduced. The bearing 100 is easy to assemble using the threaded bore 40, which is used to insert the inner rollers 11 into the outer ring housing 1. Second embodiment. Using Fig. 10, a description of a configuration of the bearing 100 according to a second embodiment is provided. Fig. 10 shows a section along each of lines III-III and IV-IV in Fig. 2. In the second embodiment, only one of the guide grooves 30 is provided to accommodate one of the axial ends 11a and 11b (see Fig. 4) of each of the inner rollers 11. This configuration is otherwise similar to that of the first embodiment. Third embodiment. Using Fig. 11, a description is provided of a configuration of the bearing 100 according to a third embodiment. Fig. 11 shows a section along line VV of Fig. 1. In the third embodiment, instead of the threaded bore 40, a bore 42, which has no thread, is formed in the outer ring housing 1. The bore 42 may have a tapered surface to facilitate the insertion of the inner rollers 11. Fourth embodiment. A description of the radius “b” of each of the inner rollers 11 in the fourth embodiment is provided, which prevents the rollers 10 from coming into contact with each other. Fig. 12 shows a state in which the rollers 10 are in contact with each other, with the inner roller 11 in contact with the rollers 10. It is assumed that L is a distance between a contact point “g” where the rollers 10 are in contact with each other and the bearing axis O. It is assumed that R2 is a distance from the bearing axis O to the outer circumference of the inner ring housing 2, with each roller 10 having radius “a”. The distance L can be determined as follows, using the Pythagorean theorem. It is assumed that H is a distance between the groove width 2, corresponding to the position specified by the radius R2, and the inner circumference 32 of the guide groove 30. A distance U between the center of the inner roller 11 and the contact point g, where the rollers 10 touch each other, can be determined using the formula below. The radius “b” of the inner roller 11 can be determined from a triangle connecting the axial center O1 of the roller 10, the center of the inner roller 11, and the contact point g between the rollers 10. The radius “b” of the inner roller 11 must be large compared to the state shown in Fig. 12 and therefore satisfies the following formula. A relationship between the inner roller 11 and the rollers 10, as shown in Fig. 13, is such that a triangle O1-O2-O is formed by three points: the center O1 of roller 10, the center O2 of inner roller 11, and the bearing axis O. This triangle is a right-angled triangle. If an angle θ1 at vertex O of triangle O1-O2-O with the inner rollers 11, where "n" is the number, is given by the following formula. Note that "n" is an integer greater than or equal to 3. Based on these conditions, the radius “b” of the inner roller 11 can assume a maximum of b≤(a+R2)cos(π / n)-(H+R2). Based on the foregoing conditions, the radius “b” of the inner roller 11 satisfies the formula (1) below. In the fourth embodiment, a radius (b) region of the inner roller 11, designed to prevent the rollers 10 from touching each other, can be identified using formula (1). Because contact between the rollers 10 is thereby avoided, resistance to a transient force (impact) is improved. Fifth embodiment. Although a section of each guide groove 30, which points in a circumferential direction, has the shape of a quadrilateral in the first embodiment, another shape may be used. In Fig. 14, the guide groove 30 has a triangular section pointing in the circumferential direction, and the inner roller 11 has triangular ends. In Fig. 15, the guide groove 30 has a semicircular cross-section pointing in the circumferential direction, and the inner roller 11 has semicircular ends. In Fig. 16, the guide groove 30 has a semi-elliptical cross-section pointing in the circumferential direction, and the inner roller 11 has semi-elliptical ends. The section of the guide groove 30 pointing in the circumferential direction and the ends of the inner roller 11 may have any shape, a combination of a quadrilateral, a triangle, a semicircle, and a semi-ellipse. As shown in Figs. 17, 18 to 1999, the guide groove 30 has a semicircular cross-section pointing in the circumferential direction, and the inner roller 11 has semi-elliptical ends.As shown in Fig. 19, the inner circumference 32 of the guide grooves 30 can coincide with the outer surface 1d of the outer ring housing 1, which is closer to the inner ring housing 2. In Fig. 17, the guide groove 30 has a triangular cross-section pointing in the circumferential direction. In Fig. 18, the guide groove 30 has a semicircular cross-section pointing in the circumferential direction. In Fig. 19, the guide groove 30 has a semi-elliptical cross-section pointing in the circumferential direction. In each of Figs. 14, 15, 16, 17, 18 to 19, the respective cross-sections in the left and right guide grooves 30, which point in the circumferential direction, have the same shape; however, the left and right shapes can be different. Sixth embodiment. One of the radial movements of the inner roller 11, on which the centrifugal force acts, is determined by: the position of the inner circumference 32 of the guide groove 30; the position of the outer circumference 31 of the guide groove 30; the radius “a” of each roller 10; and the radius “b” of each inner roller 11. It is difficult to determine an exact ratio between these four dimensions. Therefore, a radial clearance between the guide groove 30 and each inner roller 11 is defined. The radial distance between the guide groove 30 and each inner roller 11 is fixed greater than a fit tolerance, which is determined from a tolerance class H9 (Japanese industrial standard) for the respective diameters (2×r1) and (2×r2) of the outer circumference 31 and the inner circumference 32 of the guide groove 30, which determine the radial groove width Δr of the guide groove 30, and a tolerance class C9 (Japanese industrial standard) for the diameter (2xb) of the inner roller 11. The foregoing configurations, which are illustrated in the embodiments, are representative of the contents of the present disclosure, can be combined with other techniques which are publicly known, and can be partially omitted and modified without departing from the spirit of the present disclosure. Reference symbol list 1 Outer ring housing; 2 Inner ring housing; 10 Roller; 11 Inner roller; 20, 30 Guide groove; 40 Threaded bore; 41 Screw; O Bearing axle.

Claims

Bearing (100) comprising: an inner ring housing (2); an outer ring housing (1) arranged around the inner ring housing (2); a plurality of first rollers (10) designed to roll between an outer circumference of the inner ring housing (2) and an inner circumference of the outer ring housing (1); and a plurality of second rollers (11) arranged between adjacent first rollers (10), each of the second rollers (11) having a smaller diameter than each of the first rollers (10) and a longer axial length along an axis of rotation than each of the first rollers (10), the outer ring housing (1) having an annular guide groove (30) wherein the guide groove (30) accommodates one end of each of the plurality of second rollers (11), with the axis of rotation of each of the second rollers (11) perpendicular to a radial and circumferential direction of the bearing (100), a groove width (Δr),the length of the guide groove (30) along the radial direction of the bearing (100) is greater than the diameter of each of the second rollers (11), and a first radius (r1) representing a distance from a bearing axis (O) to an inner wall surface of the guide groove (30) that is on the outside in the radial direction of the bearing (100) is less than a distance from the bearing axis (O) to an axial center (O1) of the first roller (10) plus a radius (b) of the second roller (11), wherein the radius (b) of the second roller (11) is greater than a first value of the radius (b) of the second roller (11) that is fixed such that the first rollers (10) are in contact with each other and the second roller (11) is in contact with adjacent first rollers (10), wherein the radius (b) of the second roller (11) is less than a second value of the radius (b) of the second roller (11) that is fixed such that is that a roller (10) originates from the axial center (O1),The triangle formed at the axial center of the second roller (11) adjacent to the first roller (10) and the bearing axis (O) is a right-angled triangle. Bearing (100) comprising: an inner ring housing (2); an outer ring housing (1) arranged around the inner ring housing (2); a plurality of first rollers (10) designed to roll between an outer circumference of the inner ring housing (2) and an inner circumference of the outer ring housing (1); and a plurality of second rollers (11) arranged between adjacent first rollers (10), each of the second rollers (11) having a smaller diameter than each of the first rollers (10) and a longer axial length along an axis of rotation than each of the first rollers (10), the outer ring housing (1) having an annular guide groove (30) wherein the guide groove (30) accommodates one end of each of the plurality of second rollers (11), with the axis of rotation of each of the second rollers (11) perpendicular to a radial and circumferential direction of the bearing (100), a groove width (Δr),the length of the guide groove (30) along the radial direction of the bearing (100) is greater than the diameter of each of the second rollers (11), and a first radius (r1) represents a distance from a bearing axis (O) to an inner wall surface of the guide groove (30) that is on the outside in the radial direction of the bearing (100), which is less than a distance from the bearing axis (O) to an axial center (O1) of the first roller (10) plus a radius (b) of the second roller (11), wherein the guide groove (30) accommodates only one of the plurality of ends of each of the second rollers (11). Bearing (100) comprising: an inner ring housing (2); an outer ring housing (1) arranged around the inner ring housing (2); a plurality of first rollers (10) designed to roll between an outer circumference of the inner ring housing (2) and an inner circumference of the outer ring housing (1); and a plurality of second rollers (11) arranged between adjacent first rollers (10), each of the second rollers (11) having a smaller diameter than each of the first rollers (10) and a longer axial length along an axis of rotation than each of the first rollers (10), the outer ring housing (1) having an annular guide groove (30), the guide groove (30) accommodating one end of each of the plurality of second rollers (11), with the axis of rotation of each of the second rollers (11) perpendicular to a radial and circumferential direction of the bearing (100), a groove width (Δr),the length of the guide groove (30) along the radial direction of the bearing (100) is greater than the diameter of each of the second rollers (11), and a first radius (r1) representing a distance from a bearing axis (O) to an inner wall surface of the guide groove (30) that is on the outside in the radial direction of the bearing (100) is less than the distance from the bearing axis (O) to an axial center (O1) of the first roller (10) plus a radius (b) of the second roller (11), where, if a radius of each of the second rollers (11) is “b”, the radius “b” satisfies the following formula: L 2 + ( R2 + H ) 2 − 2 L ( R2 + H ) ) / 2 ( a + L − R2 − H ) < b ≤ ( a + R2 ) cos ( π / n ) − ( H + R2 ) ), where “a” is a radius of each of the first rollers (10), L is a distance between a contact point where the first rollers (10) touch each other and the bearing axis (O), R2 is a distance from the bearing axis (O) to an outer circumference of the inner ring housing (2), H is a distance between an outer circumference of the inner ring housing (2) and an inner circumference of the guide groove (30), and “n” is a number of the second rollers (11). Bearing (100) according to one of claims 1 to 3, wherein a second radius representing a distance from the bearing axis (O) to an inner wall surface of the guide groove (30) which is inside in the radial direction of the bearing (100) is smaller than a first radius (r1) minus a diameter of each of the second rollers (11) and larger than the first radius (r1) minus a distance to an outer surface of the outer ring housing (1) which is closer to the inner ring housing (2). Bearing (100) according to claim 1 or 3, wherein the guide groove (30) has a pair of guide grooves (30) accommodating one end of each of the second rollers (11) and an opposite end of each of the second rollers (11). Bearing (100) according to one of claims 1 to 5, wherein the outer ring housing (1) has a hole (42) to allow the insertion of the second rollers (11) into the guide groove (30) from outside the outer ring housing (1). Bearing (100) according to claim 4, wherein a radial clearance between each of the second rollers (11) and the guide groove (30) is greater than a fit tolerance determined from a tolerance class H9 for a diameter defining an inner wall surface of the guide groove (30) that is outside in the radial direction of the bearing (100), and for a diameter defining an inner wall surface of the guide groove (30) that is inside in the radial direction of the bearing (100), and from a tolerance class c9 for the diameter of each of the second rollers (11).

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