Roller bearing, roller bearing unit, electric motor, and method for manufacturing a roller bearing

Abstract

The roller has a chamfer portion formed at each of axial ends of an outer peripheral surface of the roller, and a roller inclined surface. In a cross section obtained by cutting a face including a rotation axis of the roller and a bearing center axis, if a radial position of the roller inclined surface corresponding to an end portion of the guide face is set as a first position, a radial position corresponding to a boundary of the chamfer portion and the roller inclined surface is set as a second position, an intersection angle of a tangent line of the roller inclined surface at the first position and a perpendicular line of the rotation axis is set as α, an intersection angle of a tangent line of the roller inclined surface at the second position and the perpendicular line of the rotation axis is set as β, and an intersection angle of the guide face and the perpendicular line of the bearing center axis is set as θ, α < θ < β is satisfied.

Description

TECHNICAL FIELD

[0001] The present application relates to a roller bearing, a roller bearing unit, an electric motor, a manufacturing method of a roller bearing, and a method for silencing a roller bearing. BACKGROUND

[0002] Generally, in cylindrical roller bearings, tapered roller bearings, etc., there is known a structure in which a flange portion is provided at an end portion of a raceway ring for guiding a plurality of rollers in a circumferential direction of the raceway ring, and an end surface of the roller is brought into sliding contact with the flange portion, and there are cases where high resistance to a large axial load is required (Patent Documents 1 and 2).

[0003] According to the structure of the roller bearing of Patent Document 1, the end surface of the cylindrical roller in sliding contact with the flange portion is subjected to grinding processing so that the outline of the cross section thereof becomes a specific curve, thereby improving the resistance to the axial load.

[0004] Further, in the structure of the roller bearing of Patent Document 2, a convex bulging portion passing through a first position and a second position of the end surface of the cylindrical roller is provided at the end surface of the cylindrical roller, thereby improving the resistance to the axial load.

[0005] Further, generally, in rolling bearings, as one of the required performances, silencing is required, and in particular, in cylindrical roller bearings at the time of grease lubrication, it is known that a squeaking sound as one of the noises is generated when a plurality of cylindrical rollers are moved in rolling on the raceway surface of the non-load ring (including the load ring entrance and exit). As a technique for suppressing the squeaking sound as one of such noises, there are, for example, the techniques disclosed in Patent Documents 3 to 6.

[0006] The cylindrical roller bearing of Patent Document 3 prescribes the relationship between the diameter of the outer peripheral surface of the cage and the thickness of the annular gap present between the inner peripheral surface of the flange portion and the outer peripheral surface of the cage, and reduces the sound pressure level of the squeaking sound and the cage sound.

[0007] The squeaking sound-suppressing radial bearing of Patent Document 4 sandwiches a spacer between adjacent rolling elements in the annular space between the inner ring and the outer ring, the spacer having a roller guide surface for guiding the rollers, thereby suppressing the generation of the squeaking sound.

[0008] The cylindrical roller bearing of Patent Document 5 sets the profile of the rolling surface of the roller to a straight line shape parallel to the shaft at the central portion thereof, limits the inclination of the circumferential direction and the radial direction of the columnar side of the pocket of the cage, and suppresses the inclination with respect to the revolution direction of the roller and the inclination with respect to the radial direction, thereby reducing the vibration and the noise level.

[0009] The cylindrical roller bearing of Patent Literature 6 is a polygonal curved surface in which a plurality of constituent curved surfaces are connected at a certain phase angle, and the connecting points of the constituent curved surfaces have a common tangent plane, thereby preventing the generation of squeaking sounds.

[0010] Prior Art Documents

[0011] Patent Literature

[0012] Patent Literature 1: Japanese Patent Application Laid-Open (JP-A) No. 2003-21145

[0013] Patent Literature 2: Japanese Patent Application Laid-Open (JP-A) No. 2005-3121

[0014] Patent Literature 3: Japanese Patent Application Laid-Open (JP-A) No. Hei 9-291942

[0015] Patent Literature 4: Japanese Patent Application Laid-Open (JP-A) No. Hei 6-58334

[0016] Patent Literature 5: Japanese Patent Application Laid-Open (JP-A) No. Hei 11-344035

[0017] Patent Literature 6: Japanese Patent Application Laid-Open (JP-A) No. Sho 62-270825 SUMMARY

[0018] PROBLEMS TO BE SOLVED BY THE INVENTION

[0019] However, in the case where the end surface shape of the roller is defined by a curve passing through the above-mentioned points, in the case where the end surface of the roller has a large radius of curvature (close to a straight line), a discontinuous edge portion is confirmed to be generated at the intersection of the end surface of the roller and the chamfer formed at the axial end portion of the end surface. If such an edge portion exists, in the case where a large axial load is received, or in the case where the roller is deflected at high speed, the edge portion of the roller comes into contact with the flange portion, and edge load is easily generated. Therefore, under severe use conditions, the contact surface pressure increases depending on the situation, and it is likely to become a main cause of temperature rise, seizure, and the like.

[0020] In addition, generally, in a roller bearing, in order to alleviate the edge load of the roller caused by the load, the roller rolling surface is sometimes provided in a drum shape. In Patent Literature 3, by providing the roller rolling surface in a full straight shape, the movement of the rolling element (roller) which becomes a main cause of squeaking sounds is suppressed. Also, while the movement of the roller is suppressed, the cage also restricts the movement of the cage by the thickness of the annular gap present between the inner peripheral surface of the flange portion formed at the end portion of the outer ring and the outer peripheral surface of the cage.

[0021] According to such a cage, the disturbing vibration of the rollers in the pockets is suppressed by the attenuation characteristic of the cage resulting from the viscous characteristic of the lubricant present between the cage and the outer ring or the inner ring. Also, even in the case where the rollers produce a sliding-accompanying behavior in some situations (a squeak generation factor), the behavior of the rollers in each pocket can be damped based on the attenuation characteristic of the lubricant viscosity, so the squeak can be suppressed. In Patent Documents 4 to 6, too, the squeak can be suppressed for the same reason as above.

[0022] However, it is difficult to completely restrict the behavior of the rollers, and for example, in the case where a manufacturing deviation occurs in the shape of the rolling surface of the rollers, such as a tilt, a concave-convex, etc., the rollers easily become a non-uniform motion, and sometimes a behavior that loses stability occurs. Also, in the case where the lubricant is unevenly provided between the rolling surface of the rollers and the outer ring (or the inner ring), the rollers sometimes cause a tilt, and there is a limit in reliably preventing a squeak.

[0023] Furthermore, the squeak of the ball bearing and the cylindrical roller bearing assembled in a medium- or large-sized motor can be prevented by applying a preload to the bearing in the case of the ball bearing, but in the case of the cylindrical roller bearing, the load of the preload (radial preload, axial preload) sometimes causes abnormal heat generation, and the preload cannot be simply applied. Therefore, the current situation is that the squeak of the cylindrical roller bearing has not been completely prevented or solved.

[0024] Therefore, a first object of the present application is to provide a roller bearing and a manufacturing method of a roller bearing, in which the contact of the end surface of the roller and the flange portion becomes a contact with each other in a continuous surface shape without edge collision, and a high axial resistance can be obtained even when a large axial load or a tilt occurs.

[0025] In addition, a second object of the present application is to provide a roller bearing, a roller bearing unit, and a motor, in which the heat generation caused by edge load can be suppressed, and the generation of a squeak can be prevented, and a silent method of a roller bearing.

[0026] Technical means for solving the problem

[0027] The present application has the following structure.

[0028] (1) A roller bearing, comprising: an outer ring having a raceway surface on an inner peripheral surface; an inner ring having a raceway surface on an outer peripheral surface; and a plurality of rollers disposed between the outer ring and the inner ring so as to be rotatable, wherein

[0029] A flange portion is formed in one or both of the outer ring and the inner ring, the flange portion being provided projecting in a radial direction from the raceway surface, the flange portion having a guide surface that guides the rolling element by sliding contact with a rolling element end surface,

[0030] The rolling element has a chamfer portion formed at both axial ends of a rolling element outer peripheral surface, and a rolling element inclined surface provided from an axial end of the chamfer portion toward a rolling element inner diameter side of the rolling element end surface, and opposing the guide surface of the flange portion,

[0031] In a cross section obtained by cutting a plane including a rotation axis of the rolling element and a bearing center axis, when a radial position of an end of the rolling element inclined surface opposite the flange portion protruding side of the guide surface is set as a first position, a radial position of a boundary of the chamfer portion and the rolling element inclined surface is set as a second position, an intersection angle of a tangent line of the rolling element inclined surface at the first position and a perpendicular line of the rotation axis of the rolling element is set as α, an intersection angle of a tangent line of the rolling element inclined surface at the second position and the perpendicular line of the rotation axis of the rolling element is set as β, and an intersection angle of the guide surface and a perpendicular line of the bearing center axis is set as θ,

[0032] α < θ < β is satisfied.

[0033] (2) A rolling element bearing unit, comprising:

[0034] (1) The rolling element bearing described above; and

[0035] a restriction portion that restricts axial movement of the inner ring or the outer ring that receives a pre-load from the pre-load portion,

[0036] When the outer ring or the inner ring, which is a rotation ring of the rolling element bearing, rotates, a squeaking sound is prevented by an axial pre-load in a predetermined direction that always brings both end surfaces of all the rolling elements assembled in the rolling element bearing into contact with each of the flange portions.

[0037] (3) An electric motor, comprising:

[0038] a rotation axis having a rotor;

[0039] a housing having a stator; and

[0040] (2) The rolling element bearing unit described above, which rotatably supports the rotation axis in the housing.

[0041] (4) A manufacturing method of a rolling element bearing, wherein,

[0042] The roller bearing includes an outer ring having a raceway surface on an inner peripheral surface, an inner ring having a raceway surface on an outer peripheral surface, and a plurality of rollers disposed between the outer ring and the inner ring so as to be rotatable,

[0043] A flange portion is provided on one or both of the outer ring and the inner ring, the flange portion protruding radially from the raceway surface, the flange portion having a guide surface that slides in contact with a roller end surface of the roller to guide the roller,

[0044] The roller has a chamfer portion formed at both axial ends of a roller outer peripheral surface, and a roller inclined surface provided at an axial end of the chamfer portion toward a roller inner diameter side of the roller end surface, and opposing the guide surface of the flange portion,

[0045] In a cross section obtained by cutting a surface including a rotation axis of the roller and a bearing center axis, when a radial position of an end portion of the flange portion of the roller inclined surface opposite to the first position is set as a second position, an intersection angle of a tangent line of the roller inclined surface at the first position and a perpendicular line of the rotation axis of the roller is set as α, an intersection angle of a tangent line of the roller inclined surface at the second position and the perpendicular line of the rotation axis of the roller is set as β, and an intersection angle of the guide surface and the perpendicular line of the bearing center axis is set as θ,

[0046] α < θ < β is satisfied.

[0047] (5) A roller bearing noise reduction method, wherein

[0048] The roller bearing includes an outer ring having a raceway surface on an inner peripheral surface, an inner ring having a raceway surface on an outer peripheral surface, and a plurality of cylindrical rollers as rollers, the plurality of cylindrical rollers being rotatably disposed between the outer ring and the inner ring,

[0049] The outer ring and the inner ring are each formed with a flange portion protruding radially from the raceway surface and having a guide surface that slides in contact with a roller end surface of the roller to guide the roller,

[0050] An axial pre-load of a constant pressure in an axial direction is applied to one side and the other side of side surfaces of the outer ring and the inner ring, that is, a side surface of the outer ring and a side surface of the inner ring, to prevent squeaking, the axial pre-load causing both end surfaces of all the rollers assembled in the roller bearing to be in contact with each of the flange portions at all times when the outer ring or the inner ring as a rotation ring of the roller bearing is rotated.

[0051] Effects of the Invention

[0052] According to the present application, the contact of the end surface of the roller with the flange portion becomes contact with each other in a continuous surface shape without edge collision, and high axial resistance can be obtained even when a large axial load, deflection is generated.

[0053] Further, according to the present application, generation of squeal of the cylindrical roller bearing can be completely prevented. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 is a partial sectional view of a roller bearing according to a first embodiment of the present application.

[0055] Figure 2 is an enlarged view of the S portion of Figure 1 is a partial enlarged explanatory view showing a state in which the cylindrical roller is separated from the flange portion.

[0056] Figure 3 is a main part schematic sectional view of a roller bearing unit of the roller bearing provided with Figure 1

[0057] Figure 4 is a schematic sectional view of a motor in which the roller bearing shown in Figure 1 and the roller bearing unit shown in Figure 3 are applied to support of a motor rotating shaft.

[0058] Figure 5 is an enlarged sectional view of the flange portion and the cylindrical roller showing a first structure example.

[0059] Figure 6 is a schematic view schematically showing a result of measurement of the shape of the end surface of the cylindrical roller of the first structure example.

[0060] Figure 7 is a schematic view schematically showing a result of measurement of the shape of the end surface of the cylindrical roller of the second structure example.

[0061] Figure 8 is a sectional view of the flange portion and the cylindrical roller showing a third structure example.

[0062] Figure 9 is a sectional view of the flange portion and the cylindrical roller showing a fourth structure example.

[0063] Figure 10 is a graph showing a result of performance test, and is a graph showing a change in bearing outer ring temperature over time.

[0064] Figure 11 is a graph showing a result of performance test, and is a graph showing a change in bearing outer ring temperature over time.

[0065] ​Figure 12 is a sectional view showing a tapered roller bearing having tapered rollers.

[0066] Figure 13 is a sectional view showing a cross roller bearing having cylindrical rollers.

[0067] Figure 14 is a test result of Test Example Bl, and is a graph showing changes in bearing outer ring temperature, bearing vibration, and rotational speed with respect to test time.

[0068] Figure 15 is a test result of Test Example B2, and is a graph showing changes in bearing outer ring temperature, bearing vibration, and rotational speed with respect to test time.

[0069] Figure 16 is a test result of Test Example B3, and is a graph showing changes in bearing outer ring temperature, bearing vibration, and rotational speed with respect to test time.

[0070] Figure 17 is a test result of Test Example B4, and is a graph showing changes in bearing outer ring temperature, bearing vibration, and rotational speed with respect to test time.

[0071] Figure 18 is a graph showing the distribution of bearing vibration with respect to axial pre-load in each of Test Examples Bl to B4, and is a graph showing the range in which squeaking occurs and the range in which it does not occur.

[0072] Figure 19 is a graph showing Figure 1 , Figure 2 the behavior of bearing temperature and bearing vibration in the cylindrical roller bearing shown in FIGS. 1 to 5.

[0073] Explanation of Symbols

[0074] 11 outer ring

[0075] 11a outer ring raceway surface

[0076] 12a, 12b outer ring flange portion

[0077] 13 inner ring

[0078] 13a inner ring raceway surface (raceway surface)

[0079] 15 cylindrical roller (roller)

[0080] 15a roller end surface

[0081] 15b roller rolling (outer peripheral) surface

[0082] 15c roller inclined surface

[0083] 16a, 16b outer ring side surface

[0084] 17 retainer

[0085] 18 outer peripheral surface

[0086] 19 inner ring flange portion

[0087] 19a guide surface

[0088] 21 chamfered portion

[0089] 23 ground avoidance portion of flange portion base end

[0090] 24 ground avoidance portion of inner ring raceway surface side

[0091] 25a, 25b inner ring side surface

[0092] 31 tapered roller (roller)

[0093] 33 cylindrical roller (roller)

[0094] 50 preloading portion

[0095] 51 spring portion

[0096] 53 inner ring retainer ring

[0097] 60 restriction portion

[0098] 61 outer ring retainer ring

[0099] 70 housing

[0100] 80 shaft

[0101] 91 rotor

[0102] 93 stator

[0103] 100 cylindrical roller bearing (roller bearing)

[0104] 100A tapered roller bearing (roller bearing)

[0105] 100B cross roller bearing (roller bearing)

[0106] 200 bearing unit

[0107] 300 motor DETAILED DESCRIPTION

[0108] An exemplary embodiment of the present application will be described in detail below with reference to the accompanying drawings.

[0109] Figure 1 is a partial cross-sectional view of a roller bearing according to a first embodiment of the present application.

[0110] The roller bearing 100 includes an outer ring 11, an inner ring 13, cylindrical rollers 15, and a cage 17. The inner ring 13 has: an inner ring raceway surface 13a that contacts the cylindrical rollers 15; and an inner ring flange 19 formed on one side of the inner ring raceway surface 13a in the width direction, i.e., on the axial side. Figure 1 (the right end) and protrudes toward the outer ring 11; and the inner ring sides 25a, 25b.

[0111] The outer ring 11 has: an outer ring raceway surface 11a that contacts the cylindrical roller 15; outer ring flanges 12a and 12b that are formed on both sides of the outer ring raceway surface 11a in the width direction and protrude toward the inner ring 13 respectively; and outer ring side surfaces 16a and 16b.

[0112] The cylindrical roller 15 has an outer peripheral surface 15b and an end face 15a that are in rolling contact with the outer raceway surface 11a and the inner raceway surface 13a.

[0113] The inner ring flange 19 has a guide surface 19a that guides the cylindrical roller 15 along the circumferential direction of the outer ring 11 and the inner ring 13. The roller end face 15a slides in contact with the guide surface 19a of the inner ring flange 19, thereby causing the cylindrical roller 15 to roll on the inner ring raceway surface 13a.

[0114] Figure 2 yes Figure 1 The enlarged view of section S is a partially enlarged explanatory diagram showing the state in which the cylindrical roller 15 is separated from the inner ring flange 19. Additionally, Figure 2 This represents the cross-section obtained by cutting along the plane containing the rotating shaft L1 of the cylindrical roller 15 and the bearing center shaft L2, with the X direction being axial and the Y direction being radial. In the figure, T represents the intersection of the chamfer (bevel) of the inner ring flange 19 and the guide surface 19a.

[0115] The inner flange portion 19 has a guide surface 19a, which guides the cylindrical roller 15 along... Figure 1 The outer ring 11 and inner ring 13 are shown as circumferential guides. The guide surface 19a is a continuous annular surface along the circumferential direction.

[0116] The cylindrical roller 15 has the following features: a chamfer (bevel) 21 that is reduced in diameter from one end of the outer peripheral surface 15b of the roller along the rotation axis L1 away from the inner raceway surface 13a; and a roller inclined surface 15c that is formed from the axially outer end of the chamfer 21 toward the radially inner side of the roller end face 15a and is opposite to the guide surface 19a of the inner ring flange 19.

[0117] The end face 15a of the cylindrical roller 15 that slides in contact with the inner ring flange 19 is formed by grinding with an elastic grinding wheel (not shown).

[0118] The surface roughness Ra of the roller inclined surface 15c is preferably 0.1 μm or less, more preferably 0.05 μm or less, and further preferably 0.03 μm or less. Thereby, the friction between the roller inclined surface 15c and the guide surface 19a of the flange portion 19 of the inner ring can be reduced, the oil film formation is good, and the allowable rotational speed of the roller bearing 100 can be increased. In addition, it is also advantageous for the improvement of seizure resistance and seizure.

[0119] Here, in the cross section shown in FIG. 1, the radial position of the end portion T of the roller inclined surface 15c opposite to the flange portion protruding side of the guide surface 19a is set as a first position A, and the radial position of the roller inclined surface 15c corresponding to the boundary of the chamfer portion 21 and the roller inclined surface 15c is set as a second position B. The "opposite" herein means the same radial position. In addition, the position of the axial end of the chamfer portion 21 on the side opposite to the second position B is set as a third position C. Figure 2

[0120] The intersection angle of the tangent line L3 of the roller inclined surface 15c at the first position A and the perpendicular line of the rotation axis LI of the cylindrical roller 15 is set as α, the intersection angle of the tangent line L4 of the roller inclined surface 15c at the second position B and the perpendicular line of the rotation axis LI of the cylindrical roller 15 is set as β, and the intersection angle of the guide surface 19a and the perpendicular line of the bearing center axis L2 (refer to FIG. 1) (herein synonymous with the perpendicular line of the rotation axis LI of the cylindrical roller 15) is set as θ. θ is equal to the flange opening angle of the inner ring flange portion 19. Figure 1

[0121] The allowable tolerance when manufacturing the inner ring 13 is set as ±δ, and the intersection angle θ of the guide surface 19a is made as a target value of θ±δ. The value of δ representing the allowable range is adopted, for example, values of 5', 3', (2'), etc. according to each condition of the bearing, the use, the size, etc.

[0122] At this time, the intersection angle α at the first position A and the intersection angle β at the second position B described above are set as (1), and preferably as (2).

[0123] α < θ < β (1) (α + δ) < θ < (β - δ) (2)

[0124] As described above, by using the intersection angle α at the first position A and the intersection angle β at the second position B to determine the shape of the roller inclined surface 15c, the abutting point at which the guide surface 19a of the inner ring flange portion 19 and the roller inclined surface 15c of the cylindrical roller 15 abut falls between the first position A and the second position B.

[0125] ​​The above will be specifically described. For example, if the allowable tolerance of the intersection angle θ = 20' of the guide surface 19a of the inner ring flange portion 19 is ±3', then according to the above (1), in the case where the intersection angle θ is 20', the intersection angle α at the first position A is set to be smaller than 20', and the intersection angle β at the second position B is set to be larger than 20', preferably according to (2), the intersection angle α at the first position A is set to be smaller than 17' (= 20' - 3'), and the intersection angle β at the second position B is set to be larger than 23' (= 20' + 3').

[0126] Thus, if the contact point of the guide surface 19a of the inner ring flange portion 19 and the roller end surface 15a of the cylindrical roller 15 is the first position A, the roller end surface 15a has a tilt smaller than the minimum allowable value of the tilt of the guide surface 19a, and thus the contact point does not move to the radially inner side of the roller than the first position A. Also, if the contact point is the second position B, the roller end surface 15a has a tilt larger than the maximum allowable value of the guide surface 19a, and thus the contact point does not move to the radially outer side of the roller than the second position B. Thus, the contact point of the guide surface 19a and the roller end surface 15a falls within the range of the roller end surface 15a from the first position A to the second position B. That is, the annular range of the roller end surface 15a from the first position A to the second position B becomes the effective contact surface with the inner ring flange portion 19.

[0127] Thus, no edge collision occurs between the roller end surface 15a and the guide surface 19a of the inner ring flange portion 19. Even if an edge exists at the intersection of the roller end surface 15a and the chamfer portion (chamfer portion) 21, no edge collision occurs with the guide surface 19a of the inner ring flange portion 19 due to skewing or the like. Thus, generation of sharp heat due to sharp edge load can be prevented.

[0128] In addition to this, as shown in Figure 2 the inner diameter side of the inner ring flange portion 19), the clearance between the inner ring flange portion 19 and the cylindrical roller 15 is large. Thus, intake of lubricating oil (and grease) within the bearing can be smoothly performed. Thus, at the actual contact point within the effective contact surface between the first position A and the second position B, the surface pressure is reduced without generating edge load. As a result, sufficient lubrication performance can be obtained, and a structure with excellent cooling effect is obtained.

[0129] Note that the inner ring flange portion 19 shown here does not have a grinding avoidance portion in the axial direction, and the roller end surface 15a is formed in a so-called face chamfer shape with a large amount of bulging and continuity. Note that, for the grinding avoidance in the above (1), the intersection angle θ of the guide surface 19a of the inner ring flange portion 19 and the roller end surface 15a of the cylindrical roller 15 is set to be within a range of 17' to 23' (17' ≤ θ ≤ 23'). Figure 2 Note that the inner ring flange portion 19 shown here does not have a grinding avoidance portion in the axial direction, and the roller end surface 15a is formed in a so-called face chamfer shape with a large amount of bulging and continuity. Note that, for the grinding avoidance in the above (1), the intersection angle θ of the guide surface 19a of the inner ring flange portion 19 and the roller end surface 15a of the cylindrical roller 15 is set to be within a range of 17' to 23' (17' ≤ θ ≤ 23').Figure 1 ) between the third position C and the point at which the inner-ring raceway surface 13a and the guide surface 19a of the inner-ring flange portion 19 abut, a grinding avoidance portion 24 is provided on the inner-ring raceway surface 13a side. The grinding avoidance portion 24 can be formed between the intersection (not shown) of the inner-ring raceway surface 13a and the guide surface 19a of the inner-ring flange portion 19 and the point C on the inner-ring raceway surface 13a (preferably closer to the intersection than the point C). The grinding avoidance portion 24 is preferably formed by turning processing (hard turning processing) after heat treatment.

[0130] In the above-described structure, the inner-ring flange portion 19 is provided on the inner ring 13, but the flange portion is not limited to the inner ring 13, and can be a flange portion formed on the outer ring 11.

[0131] In the case where the flange portion is formed on the inner ring 13, the first position A and the second position B described above are provided on the bearing small-diameter side from the intersection of the flange portion chamfer and the guide surface.

[0132] In the case where the flange portion is formed on the outer ring 11, the first position A, the second position B described above are provided on the bearing large-diameter side from the intersection of the flange portion chamfer and the guide surface.

[0133] In any case, in the roller 15, the first position A is the small-diameter side of the roller inclined surface, and the second position B is the large-diameter side of the roller inclined surface.

[0134] Further, the second position B at which the roller inclined surface 15c and the chamfer 21 are connected is formed by a smooth curved surface having no edge. At the intersection of the roller inclined surface 15c formed by a curved line and the chamfer 21 formed by a straight line in the axial cross section, an edge generally exists, but in the present structure, it is continuously formed as a smooth curved surface having no edge. Such a curved surface having no edge can be formed by, for example, a spline curve, a Bezier curve, or the like. The connection processing for processing the connection portion can be, for example, grinding processing using a flexible grinding wheel, but is not limited thereto. Thus, edge collision does not occur, and generation of sharp heating of the roller bearing 100 due to edge load can be prevented.

[0135] < Axial Pre-Load >

[0136] Further, the roller bearing 100 of the present structure effectively prevents generation of squeaking by applying an axial pre-load to the bearing.

[0137] Normally, in roller bearings, there are non-load-bearing portions (non-load rings) within the bearing. However, in the roller bearing 100 of this structure, an axial preload is applied in such a way that all the cylindrical rollers 15 arranged in the non-load rings bear a specified load. That is, an axial preload is applied to one side of the outer ring 11 and the other side of the inner ring 13, specifically on one side of the outer ring 11 (outer ring side 16a) and the other side of the inner ring 13 (inner ring side 25b). Thus, the cylindrical rollers 15 are constrained, and their movement is restricted. This prevents squeaking noise and results in a roller bearing 100 that can rotate while maintaining a quiet operation.

[0138] <Cylindrical Roller Bearing Unit>

[0139] Next, the roller bearing unit 200 that uses the roller bearing 100 described above and is able to prevent the generation of squeaking noise will be described.

[0140] Figure 3 It means possessing Figure 1 A schematic cross-sectional view of the main parts of the roller bearing unit 200 of the roller bearing 100.

[0141] The roller bearing unit 200 includes a roller bearing 100, a preload section 50, and a limiting section 60.

[0142] One of the preload portion 50 and the limiting portion 60 is disposed on the housing 70 side, and the other is disposed on the shaft 80 side. Figure 3 The diagram shows a structure with a limiting part 60 disposed on the housing 70 side and a preload part 50 disposed on the shaft 80 side. However, the limiting part 60 can also be disposed on the shaft 80 side and the preload part 50 on the housing 70 side. Alternatively, the preload part 50 and the limiting part 60 can be disposed together on the housing 70 side as described later. That is, the preload part 50 and the limiting part 60 can be disposed diagonally in a cross-section along the axial direction X.

[0143] exist Figure 3 The housing 70 shown is fixed with the outer peripheral surface 18 of the outer ring 11 and one side of the outer ring 11 ( Figure 3 The outer ring retaining ring 61, which serves as a limiting part 60, abuts against the outer ring side 16a (left side). The outer ring retaining ring 61 can be a circular ring or a wall portion protruding from the housing 70 toward the inner ring 13. The outer ring retaining ring 61 prevents axial displacement of the outer ring 11 caused by the axial preload described later.

[0144] The shaft 80 is provided with an inner circumferential surface 29 of an inner ring 13, and the other side of the inner ring 13 ( Figure 3The inner ring 100 consists of a spring portion 51 abutting against the inner ring side surface 25b (right side of the bearing 80) and an inner ring retaining ring 53 pressing the spring portion 51 toward the inner ring side surface 25b. The inner ring retaining ring 53 can be a structure threaded to the shaft 80 or a stepped portion protruding radially outward from the shaft 80 itself. The spring portion 51 and the inner ring retaining ring 53 constitute a preload portion 50. The preload portion 50 presses against the inner ring side surface 25b of the inner ring flange portion 19, applying an axial preload load to the roller bearing 100. The preload portion 50 can be any structure that can press the inner ring side surface 25b axially. In addition, the axial preload load can be changed to an appropriate preload by changing the elastic coefficient of the spring portion 51 or the thread tightness of the inner ring retaining ring 53.

[0145] The housing 70 is a frame that covers the roller bearing 100 and positions the cylindrical roller bearing 100 in a specified position. Examples of housings include vertical blocks, wheel housings, and motor housings.

[0146] According to the roller bearing unit 200 with the above structure, the shaft 80 and the housing 70 can be supported by the roller bearing 100 for relative rotational freedom, and an axial preload can be applied to the roller bearing 100. Therefore, by applying an axial preload to the roller bearing 100, as described above, the generation of squeaking noise can be prevented.

[0147] Furthermore, either a constant pressure preload mechanism or a fixed position preload mechanism can be used as the preload section 50. When a preload is applied via a constant pressure preload mechanism such as a spring, a constant preload can be ensured even if the roller bearing 100 experiences internal wear, which is therefore preferable.

[0148] <Electric Motor>

[0149] Figure 4 It is Figure 1 The roller bearing 100 shown and Figure 3 The shown roller bearing unit 200 is a schematic cross-sectional view of a motor 300 used to support the rotating shaft of a motor.

[0150] The electric motor 300 includes a housing 70, a shaft 80 that rotates through the housing 70, a rotor 91 fixed to the shaft 80, a stator 93 that surrounds the rotor 91 and is fixed to the housing 70, and at least one pair of roller bearing units 200 that support the shaft 80 in the housing 70.

[0151] According to the electric motor 300 of this structure, the roller bearing 100 described above is used to apply an axial preload to the roller bearing 100, thereby preventing the generation of squeaking noise and enabling silent operation.

[0152] [Example]

[0153] Next, a specific example of the shape of the end surface of the roller and the shape of the guide surface of the flange portion will be described.

[0154] <First Structure Example>

[0155] Figure 5 is an enlarged sectional view showing the inner ring flange portion 19 and the cylindrical roller 15 of the first structure example.

[0156] In the first structure example, the end portion of the guide surface 19a on the inner ring raceway surface side is not formed with an axially extending grinding avoidance portion, but has a radially extending grinding avoidance portion 24 at the end portion of the inner ring raceway surface 13a, and the roller end surface 15a becomes a continuously chamfered shape with a large amount of bulging.

[0157] The cylindrical roller bearing 100 manufactured with the allowable range of the intersection angle θ of the guide surface 19a of the inner ring flange portion 19 set to 20' ± 3' was prepared, and the outer shape of the cylindrical roller 15 was measured. In particular, the coordinates of the roller end surface 15a at an arbitrary point Pl between the first position A and the second position B of the roller end surface 15a were measured, and the slope of the tangent line L5 (change in drop amount per 0.1 mm in the axial direction) was calculated from the coordinates obtained.

[0158] Figure 6 is a schematic view schematically showing the results of measuring the end surface shape of the cylindrical roller of the first structure example. In Figure 6 , Ll indicates the rotation axis of the cylindrical roller. The slope of the tangent line was calculated from the measurement results of the end surface outer shape of the cylindrical roller, and as a result, in one pair of roller end surfaces, the slope of the tangent line at the first position A-1 (corresponding to A of Figure 5 ) of one roller end surface was 9.5', the slope of the tangent line α at the first position A-2 (position corresponding to A of Figure 5 , 180° opposite phase side of A-1) of the same roller, the same end surface was 10.1', and the slope of the tangent line at any position was less than 20' and less than 17'. Of course, the slope of the tangent line at A-1, A-2 of the opposite side end surface of the same roller was also less than 20' and less than 17', respectively.

[0159] In addition, the slope of the tangent line β at the second position B-1 (corresponding to B of Figure 5 ) of one roller end surface was 66.6', the slope of the tangent line at the second position B-2 (corresponding to B of Figure 5 ) (180° opposite phase side of Bl) of the same roller, the same end surface was 86.7', and the slope of the tangent line at any position was greater than 20' and greater than 23'. Of course, the slope of the tangent line at B-1, B-2 of the opposite side end surface of the same roller was also greater than 23', respectively.

[0160] In the case of the first structure example, between the first position A-1 to the second position B-1 and between the first position A-2 to the second position B-2 from the contact point of the roller end surface 15a and the guide surface 19a of the inner ring flange portion 19, the inclination of the allowable range of the inclination of the guide surface 19a described above is obtained. Therefore, the positions of the roller end surface 15a that are radially inside the first positions A-1, A-2 and radially outside the second positions B-1, B-2 cannot be the contact points with the guide surface 19a. Therefore, the roller end surface 15a does not collide with the edge of the guide surface 19a, and the intersection of the roller end surface 15a and the chamfer portion 21 (chamfer) does not contact the guide surface 19a even if the intersection is skewed or the like. Thus, heating caused by a sharp edge load does not occur.

[0161] Further, as shown in Figure 5 , the gap Wa between the inner ring flange portion 19 at the first position A and the cylindrical roller 15 and the gap Wb between the inner ring flange portion 19 at the second position B and the cylindrical roller 15 are both large, and the intake of lubricating oil (and grease) inside the bearing becomes smooth.

[0162] <Second Structure Example>

[0163] Figure 7 is a schematic diagram that schematically shows the results of measuring the shape of the cylindrical roller of the second structure example. In Figure 7 , L1 indicates the rotation axis of the cylindrical roller 15.

[0164] The roller end surface 15a of the second structure example is also, as with the first structure example shown in Figure 6 , a chamfer shape having continuity, but the bulge of the roller end surface 15a is smaller.

[0165] The outer shape of the cylindrical roller 15 manufactured with the allowable range of the intersection angle θ of the guide surface 19a of the inner ring flange portion 19 set to 20' ± 3' was measured.

[0166] The slope of the tangent line was calculated from the results of the measurement of the outer shape, and as a result, the slope α of the tangent line at the first position A-1 of one of the pair of roller end surfaces was 1.3', the slope of the tangent line at the first position A-2 (180° opposite phase side of A-1) of the same roller, the same end surface was 0.7', and the slope of the tangent line was less than 17' at any position. Of course, in A-1, A-2 of the opposite side end surface of the same roller, it was also less than 20' and less than 17', respectively.

[0167] Further, the slope β of the tangent line at the second position B-1 of the end surface of the same roller is 98.6', the slope of the tangent line at the second position B-2 (180° opposite phase side of B-1) of the same end surface is 104.5', and the slope of the tangent line at either position is greater than 20' and greater than 23'. Of course, the same is true at B-1 and B-2 of the opposite end surface of the same roller.

[0168] In the second structure example as well as the first structure example, the end surface 15a of the roller does not collide with the edge of the guide surface 19a, and further, the intersection of the end surface 15a of the roller and the chamfer 21 (chamfered portion) does not come into contact with the guide surface 19a even if there is a slight deviation or the like, and thus, there is no heating due to a sharp edge load. Further, both the gap Wa and the gap Wb are large, and the intake of lubricating oil (and grease) within the bearing becomes smooth.

[0169] <Third Structure Example>

[0170] Figure 8 is a cross-sectional view showing the inner ring flange portion 19 and the cylindrical roller 15 of the third structure example.

[0171] The end surface 15a of the roller of the third structure example is a ground surface formed so that the radius of curvature R is 3000 mm, and a ground avoidance portion 23 extending in the axial direction is formed at the base end of the inner ring flange portion 19. In this structure, the intermediate point P2 of the end surface 15a of the roller comes into contact with the guide surface 19a of the inner ring flange portion 19. The relationship of the intersection angle α, the intersection angle β, and the intersection angle θ is α < θ < β, but since the radius of curvature R of the end surface 15a of the roller is larger than in the first and second structure examples, the gap Wa at the first position A and the gap Wb at the second position B are smaller than in the first and second structure examples.

[0172] <Fourth Structure Example>

[0173] Figure 9 is a cross-sectional view showing the inner ring flange portion 19 and the cylindrical roller 15 of the fourth structure example.

[0174] The end surface 15a of the roller of the fourth structure example is a flat ground surface, and the relationship of the intersection angle α, the intersection angle β, and the intersection angle θ is α < θ, β < θ. A ground avoidance portion 23 extending in the axial direction is formed at the base end of the inner ring flange portion 19. In this structure, the second position B of the end surface 15a of the roller comes into contact with the guide surface 19a of the inner ring flange portion 19. Further, the gap Wa at the first position A is larger than in the first to third structure examples, but there is no gap at the second position B.

[0175] <Performance Test Results>

[0176] A cylindrical roller having the same shape as the first and second structure examples was prepared and assembled in a roller bearing NJ2326 (inner diameter Outer diameter ) raceway ring, and a roller bearing corresponding to the third and fourth structure examples was prepared, and performance tests of each roller bearing were conducted.

[0177] (Test conditions)

[0178] Radial load Fr: 90487 N (9224 kgf) was applied

[0179] Axial load Fa: 0.1 x Fr to 0.6 x Fr (radial load) was applied

[0180] Rotational speed N: 1000 min -1

[0181] Oil bath lubrication (viscosity: VG68, 500 cc = oil level at the lowermost part of the roller PCD)

[0182] Load application time: 10 hours (or more)

[0183] Allowed range for the angle of the guide surface of the inner ring flange portion: 20' ± 3' (δ = 3')

[0184] Test Example Al: Cylindrical roller of the first structure example + raceway ring of cylindrical roller bearing NJ2326

[0185] Test Example A2: Cylindrical roller of the second structure example + raceway ring of cylindrical roller bearing NJ2326

[0186] Test Example A3: Cylindrical roller of the third structure example + raceway ring of cylindrical roller bearing NJ2326

[0187] Test Example A4 (Comparative Example A4): Cylindrical roller of the fourth structure example + raceway ring of cylindrical roller bearing NJ2326

[0188] In addition, the grinding avoidance portion 24 of Test Example Al and Test Example A2 was formed by turning processing after heat treatment, and the grinding avoidance portion 23 of Test Example A3 and Comparative Example A4 was formed by turning processing before heat treatment.

[0189] Figure 10 、 Figure 11 is a graph showing the results of the performance test, and is a graph showing the change in the temperature of the bearing outer ring over time. Figure 10 is the result in the case where the radial load was applied all the time, and the axial load was increased from 0.1 x Fr to 0.2 x Fr after the axial load was set to 0.1 x Fr, Figure 11is the result in the case where the radial load is applied constantly, and the axial load is increased to 0.6 x Fr after the axial load is set to 0.5 x Fr.

[0190] In Figure 10 The test examples Al to A3 show almost the same tendency from the start of the test to 3 hours after the test, but a difference between the test example Al and the test examples A2 and A3 appears after 4 hours, and the test example Al has the lowest bearing temperature. The bearing temperature after 5 hours is 81.8°C in the test example Al, 84.8°C in the test example A2, and 85.8°C in the test example A3. Further, after 10 hours, the test example Al is 85.9°C, the test example A2 is 89.0°C, and the test example A3 is 90.6°C.

[0191] On the other hand, in the comparative example A4, the bearing temperature sharply rises from the start of the test, and reaches 120°C before 1 hour after the test.

[0192] The results in the case where the axial load is large are shown below. Figure 11 The bearing specifications in the case where the axial load is large are shown below.

[0193] Test example Al: raceway ring of cylindrical roller + cylindrical roller bearing NJ2326 of the first structural example

[0194] Test example A2: raceway ring of cylindrical roller + cylindrical roller bearing NJ2326 of the second structural example

[0195] Test example A3: raceway ring of cylindrical roller + cylindrical roller bearing NJ2326 of the third structural example

[0196] Comparative example A4: raceway ring of cylindrical roller + cylindrical roller bearing NJ2326 of the third structural example

[0197] In addition, the grinding avoidance portion 24 of Test Example Al and Test Example A2 is formed by turning processing after heat treatment, and the grinding avoidance portion 23 of Test Example A3 and Comparative Example A4 is formed by turning processing before heat treatment. There is little difference between Test Examples Al to A4 and Comparative Example A4 up to 1.5 hours, but thereafter, the bearing temperature increases in the order of Test Example Al, Test Example A2, Test Example A3, and Comparative Example A4. Furthermore, if the axial load is increased to 0.6 x Fr after 5 hours, the difference between Comparative Example A4 and Test Examples Al and A2 is enlarged, and the bearing temperature sharply increases and reaches 120°C after 7 hours for Comparative Example A4. The bearing temperature after 5 hours is 91.7°C in Test Example Al, 93.8°C in Test Example A2, 97.8°C in Test Example A3, and 98.2°C in Comparative Example A4. In addition, after 10 hours, Test Example Al is 94.4°C, Test Example A2 is 95.9°C, and Test Example A3 is 107.5°C.

[0198] Thus, for the shape of the roller end surface, the inclination at the first position A and the second position B described above is set to α < θ < β, and preferably the inclination at the first position A is set to an inclination smaller than the minimum manufacturing allowable value (θ - δ) of the guide surface of the flange portion, and the inclination at the second position B is set to an inclination larger than the maximum manufacturing allowable value (θ + δ) of the guide surface of the flange portion, and a continuous profile is provided at either position, whereby the axial performance can be improved regardless of the amount of bulging of the roller end surface.

[0199] In addition, the surface roughness Ra of the roller end surface of the cylindrical roller used in Test Example Al and Test Example A2 described above is about 0.07 to 0.10 μm, and the surface roughness Ra of the roller end surface (in the range between the first position A and the second position B) that contacts at least the flange portion of the outer (inner) ring is preferably 0.1 μm or less to achieve low heat generation.

[0200] The first to fourth structural examples described above can be replaced with Figure 1 the cylindrical roller bearing 100 shown in FIG. 1, and Figure 12 the tapered roller bearing 100A having tapered rollers 31 as shown in FIG. 2, and Figure 13 as shown in FIG. 3, can be a cross roller bearing 100B having a pair of outer rings 11A and 11B, an inner ring 13, and cylindrical rollers 33, and although the drawing is omitted, can be a cross tapered bearing having tapered rollers. In any case, high axial performance can be obtained even when a large axial load or deflection is generated.

[0201]

[0202] ​As a condition in which squeaking is likely to occur in a cylindrical roller bearing, it can be said that it is likely to occur when lubricating grease is used (it hardly occurs when oil is used), or when the rotational speed is relatively low or the radial load is relatively small. Therefore, in the NJ type (outer ring two flanges / inner ring single flange) cylindrical roller bearing 100 shown in Fig. 1, in which the cylindrical rollers 15 are made of NJ type (outer ring two flanges / inner ring single flange) cylindrical roller bearings 100 shown in Fig. 1, in which the cylindrical rollers 15 are made of Figure 1 A radial load (Fr) of a relatively small load was applied in a constant state, the axial load (Fa) was changed from 0 N (kgf) to a load in which squeaking did not occur, and at the same time, the rotational speed was changed, and it was confirmed whether squeaking occurred or not. Hereinafter, the test conditions and test results of Test Examples Bl to B4 will be described using the same symbols as those in Test Example Al. Figures 14 to 19 The test conditions and test results of Test Examples Bl to B4 will be described.

[0203] <TEST EXAMPLE Bl>

[0204] (Test Conditions)

[0205] • Test bearing: Cylindrical roller bearing (Model NJ2326) in which Model NU2326 corresponds to the case where Fa = 0

[0206] • Grease: Raremax Super (manufactured by Koyo Seiki Co., Ltd.) (Space volume: 30%, Supply capacity: about 330 g, Base oil kinematic viscosity: 70 mm 2 / s (40°C) (= cSt)

[0207] • Inner ring rotational speed: 800 min -1 , 1000 min -1 , 1200 min -1

[0208] • Criteria for determining whether squeaking occurs or not: Vibration of test bearing housing 2 m / s 2 and auditory determination

[0209] • Radial load: Fr = 22622 N (2306 kgf) (P / C = 0.02)

[0210] • Axial load (axial pre-load): Fa = 0 N, 6327 N (645 kgf) (Fa / Fr = 0.28)

[0211] • Matters to be confirmed: Whether squeaking occurs or not and the effects of the axial pre-load Fa and the rotational speed at the time of the radial load Fr (dynamic equivalent load / basic dynamic rated load: P / C = 0.02)

[0212] (Test Results)

[0213] Figure 14is the test result of Test Example Bl, and is a graph showing changes in the bearing outer ring temperature, bearing vibration, and rotational speed with respect to the test time.

[0214] • Period Tl

[0215] Inner ring rotational speed: 800 min -1

[0216] Axial pre-load: Fa = 0 N

[0217] Vibration state: After the outer ring temperature was substantially constant after about 2 hours from the start of the test, a squeaking sound (P) was generated.

[0218] • Period T2

[0219] Inner ring rotational speed: 800 min -1 ,

[0220] Axial pre-load: Fa = 6327 N

[0221] Vibration state: When the axial pre-load was applied, no squeaking sound was generated.

[0222] • Period T3

[0223] Inner ring rotational speed: 1000 min -1

[0224] Axial pre-load: Fa = 6327 N

[0225] Vibration state: If the rotational speed was increased while the axial pre-load was maintained, the outer ring temperature rose, but no squeaking sound was generated after the outer ring temperature stabilized.

[0226] • Period T4

[0227] Inner ring rotational speed: 1200 min -1 ,

[0228] Axial pre-load: Fa = 6327 N

[0229] State: The rotational speed was further increased, and no squeaking sound was generated until the outer ring temperature stabilized.

[0230] < Test Example B2 >

[0231] (Test conditions)

[0232] • Inner ring rotational speed: 800 min -1 , 1000 min -1

[0233] • Axial pre-load: Fa = 0 N, 6327 N (645 kgf) (Fa / Fr = 0.28), 9050 N (922.5 kgf) (Fa / Fr = 0.4) • Other same as Test Example Bl

[0234] (Test Results)

[0235] Figure 15 is the test results of Test Example B2, and is a graph showing changes in the temperature of the bearing outer ring, the bearing vibration, and the rotational speed with respect to the test time.

[0236] • Period Tl

[0237] Inner ring rotational speed: 1000 min -1

[0238] Axial pre-load: Fa = 0 N

[0239] Vibration state: No squeaking sound was generated until about 1.6 hours had elapsed in the state where only the radial load was applied.

[0240] • Period T2

[0241] Inner ring rotational speed: 800 min -1 ,

[0242] Axial pre-load: Fa = 0 N

[0243] Vibration state: Squeaking sound was generated immediately after the rotational speed was changed.

[0244] • Period T3

[0245] Inner ring rotational speed: 800 min -1 ,

[0246] Axial pre-load: Fa = 9050 N

[0247] Vibration state: No squeaking sound was generated while the axial pre-load was applied.

[0248] • Period T4

[0249] Inner ring rotational speed: 800 min -1 ,

[0250] Axial pre-load: Fa = 6327 N

[0251] Vibration state: No squeaking sound was generated during the period in which the axial pre-load was changed for about 2 hours.

[0252] • Period T5

[0253] Inner ring rotational speed: 1000 min -1 ,

[0254] Axial pre-load: Fa = 6327 N

[0255] Vibration state: No squeaking sound was generated during a period of about 1 hour in which the rotational speed was changed.

[0256] After the period T5, in order to confirm again the results at the rotational speed of 800 min -1 , axial pre-load Fa = 0 N at which squeaking sound was generated in Test Example Bl, the tester was temporarily stopped, and the axial pre-load Fa was also released.

[0257] • Period T6

[0258] Inner ring rotational speed: 800 min -1

[0259] Axial pre-load: Fa = 0 N

[0260] Vibration state: Squeaking sound was reliably generated, and reproducibility of Test Example Bl could be confirmed.

[0261] Test Example B3

[0262] (Test conditions)

[0263] Inner ring rotational speed: 800 min -1 , 1000 min -1 , 1200 min -1

[0264] • Radial load: Fr = 45244 N (4612 kgf) (P / C = 0.04)

[0265] • Axial pre-load: Fa = 0 N, 9050 N (922.5 kgf) (Fa / Fr = 0.2) • Other conditions are the same as in Test Example Bl

[0266] (Test results)

[0267] Figure 16 is a graph showing changes in bearing outer ring temperature, bearing vibration, and rotational speed with respect to test time, and is a test result of Test Example B3.

[0268] • Period Tl

[0269] Inner ring rotational speed: 800 min -1 ,

[0270] Axial pre-load: Fa = 0 N

[0271] Vibration state: Squeaking sound was generated from after about 1.6 hours in a state in which only a radial load was applied.

[0272] • Period T2

[0273] Inner ring rotation speed: 1000 min -1

[0274] Axial pre-load: Fa = 0 N

[0275] Vibration state: Even if the rotation speed was increased, no squeaking sound was generated. However, the vibration had a tendency to gradually increase.

[0276] • Period T3

[0277] Inner ring rotation speed: 1200 min -1

[0278] Axial pre-load: Fa = 0 N

[0279] Vibration state: Even if the rotation speed was further increased under the conditions of period T2, no squeaking sound was generated. However, the vibration had a tendency to gradually increase.

[0280] • Period T4

[0281] Inner ring rotation speed: 800 min -1 ,

[0282] Axial pre-load: Fa = 9050 N

[0283] Vibration state: Immediately after the rotation speed was decreased, a squeaking sound was generated. That is, the reproducibility of test example B3 (period Tl) could be confirmed. After the reproducibility was confirmed, no squeaking sound was generated at the axial pre-load Fa = 9050 N, and thereafter, no squeaking sound was generated for 3.5 to 4 hours.

[0284] < Test Example B4 >

[0285] (Test conditions)

[0286] • Inner ring rotation speed: 800 min -1 , 1000 min -1 , 1200 min -1

[0287] • Radial load: Fr = 22622 N (2306 kgf) (P / C = 0.02)

[0288] • Axial pre-load: Fa = 0 N, 5435 N (554 kgf) (Fa / Fr = 0.24) • Other than the above, the same as test example Bl

[0289] (Test results)

[0290] Figure 17is a test result of Test Example B4, and is a graph showing changes in bearing outer ring temperature, bearing vibration, and rotational speed with respect to test time.

[0291] • Period T1

[0292] Inner ring rotational speed: 800 min -1

[0293] Axial pre-load: Fa = 0 N

[0294] Vibration state: After the outer ring temperature was substantially constant for about 2 hours from the start of the test, a squeaking sound was generated.

[0295] • Period T2

[0296] Inner ring rotational speed: 800 min -1

[0297] Axial pre-load: Fa = 5435 N

[0298] Vibration state: If the axial pre-load was applied, the squeaking sound was smaller than when generated in Period T1, but the state in which the squeaking sound was generated continued.

[0299] • Period T3

[0300] Inner ring rotational speed: 1000 min -1

[0301] Axial pre-load: Fa = 5435 N

[0302] Vibration state: Even if the rotational speed was increased, the squeaking sound continued to be generated.

[0303] • Period T4

[0304] Inner ring rotational speed: 1200 min -1

[0305] Axial pre-load: Fa = 5435 N

[0306] Vibration state: If the rotational speed was further increased, the squeaking sound was not generated. It was confirmed that the higher the rotational speed, the more difficult it was to generate the squeaking sound.

[0307] Here, in order to confirm the reproducibility of the state in which the squeaking sound was generated, the tester was temporarily stopped, and the axial pre-load was released.

[0308] • Period T5

[0309] Inner ring rotational speed: 800 min -1

[0310] Axial pre-load: Fa = 0 N

[0311] Vibration state: The same conditions as during Tl were set again, and as a result, a squeaking sound was produced, and reproducibility could be confirmed.

[0312] <Summary of Test Results>

[0313] Figure 18 is a graph showing the distribution of bearing vibration with respect to the axial pre-load of each of Test Examples Bl to B4, and is a graph showing the range in which a squeaking sound is produced and the range in which it is not produced.

[0314] The results of the confirmation at the axial pre-load Fa = 0 N, 5435 N, 6327 N, 9050 N were that a squeaking sound was produced at less than 6327 N, but was not produced at 6327 N or more. When the outer ring or the inner ring, which is the rotating ring of the cylindrical roller bearing, is rotated, an axial pre-load that is a constant pressure in the axial direction that contacts each flange portion on one diagonal line is applied to both end surfaces of all of the cylindrical rollers assembled in the cylindrical roller bearing, and is brought into contact with the flange portion. Therefore, even when all of the rollers pass through the unloaded ring, there is no gap that moves all of the rollers in the axial direction to produce a squeaking sound. Therefore, it is presumed that the squeaking sound is suppressed.

[0315] As explained above, by removing the edge portion at the connecting position of the roller end surface 15a and the chamfer portion 21 and smoothly connecting them, it is possible to avoid heating and vibration caused by edge load when the cylindrical roller 15 contacts the opposing inner ring flange portion 19 (the same applies to the outer ring flange portion as well). By applying an axial pre-load to such a cylindrical roller bearing 100, it is possible to reliably prevent the production of a squeaking sound even in the load range and the rotational speed range in which a squeaking sound was produced in the conventional product. Figure 2

[0316] Figure 19 is a graph showing the behavior of the bearing temperature and the bearing vibration in the cylindrical roller bearing shown in Figure 1 , Figure 2 The results of the cylindrical roller bearing shown in Figure 1 , Figure 2 are shown on the graph in the form of the symbol S.

[0317] In the cylindrical roller bearing 100 of the present structure, the connecting position of the roller inclined surface 15c and the chamfer portion 21 is formed by a smooth curved surface that has no edge, and therefore heating and vibration caused by edge load can be avoided when the cylindrical roller 15 contacts the inner ring flange portion 19. In addition, even in the case where an axial pre-load of Fa = 18099 N is applied, particularly, there are no abnormalities in heating and vibration.

[0318] For example, the shape of the vicinity of the contact position of the inner ring flange portion 19 and the cylindrical roller 15 described above can also be formed in the same manner in the​Figure 1 An outer ring flange portion 12b is formed in the outer ring 11.

[0319] The cylindrical roller bearing 100 of the present embodiment shows an NJ type with two flanges of the outer ring and one flange of the inner ring, but can also be applied to NUP, NF, NH types. In any case, the shape near the contact position of the flange portion to which an axial pre-load is applied and the cylindrical roller is the same as the shape near the contact position of the inner ring flange portion 19 and the cylindrical roller 15 described above.

[0320] As described above, the present specification discloses the following matters.

[0321] (1) A roller bearing, comprising: an outer ring having a raceway surface on an inner peripheral surface; an inner ring having a raceway surface on an outer peripheral surface; and a plurality of rollers disposed between the outer ring and the inner ring so as to be rollable, wherein

[0322] A flange portion is formed in one or both of the outer ring and the inner ring, the flange portion is provided so as to protrude radially from the raceway surface, the flange portion has a guide surface that slides in contact with a roller end surface of the roller to guide,

[0323] The roller has: a chamfer portion formed at both axial ends of a roller outer peripheral surface; and a roller inclined surface provided from an axial end of the chamfer portion to a roller inner diameter side of the roller end surface, and opposing the guide surface of the flange portion,

[0324] In a cross section obtained by cutting a surface including a rotation axis of the roller and a bearing center axis, when a radial position opposite to an end portion of the flange portion of the roller inclined surface on a protruding side of the guide surface is set as a first position, a radial position of a boundary of the chamfer portion and the roller inclined surface is set as a second position, an intersection angle of a tangent line of the roller inclined surface at the first position and a perpendicular line of the rotation axis of the roller is set as a, an intersection angle of a tangent line of the roller inclined surface at the second position and the perpendicular line of the rotation axis of the roller is set as β, and an intersection angle of the guide surface and a perpendicular line of the bearing center axis is set as θ,

[0325] α < θ < β is satisfied.

[0326] According to the roller bearing, if the contact point of the flange portion guide surface and the roller end surface is the first position A, the roller end surface has a smaller inclination than the guide surface inclination, so the contact point does not move more radially inward than the first position A. Also, if the contact point is the second position, the roller end surface has a larger inclination than the guide surface, so the contact point does not move more radially outward than the second position. Therefore, the contact point of the flange guide surface and the roller end surface falls within the range of the roller end surface from the first position to the second position. Thus, edge collision does not occur between the roller end surface and the guide surface, and generation of sharp heat due to sharp edge load can be prevented. Thus, even when a large axial load, deflection occurs, a higher axial resistance can be obtained. Also, the clearance of the roller end surface and the guide surface is ensured, lubricant supply becomes good, and cooling effect can be improved.

[0327] (2) The roller bearing according to (1), wherein

[0328] An end portion of the raceway surface side of the guide surface is not formed with an axially extending grinding avoidance portion, and is formed with a radially extending grinding avoidance portion.

[0329] According to the roller bearing, since the edge of the roller end surface portion and the flange guide portion do not contact, generation of edge load can be prevented, and axial resistance can be improved.

[0330] (3) The roller bearing according to (1) or (2), wherein

[0331] The surface roughness Ra of the guide surface is 0.1 μm or less.

[0332] According to the roller bearing, heat generation due to sliding contact of the flange guide surface and the roller end surface can be suppressed.

[0333] (4) The roller bearing according to any one of (1) to (3), wherein

[0334] The roller bearing is any one of a cylindrical roller bearing, a tapered roller bearing, a cross roller bearing having cylindrical rollers, and a cross tapered bearing having tapered rollers.

[0335] According to the roller bearing, even when a large axial load, deflection occurs, a high axial resistance can be obtained.

[0336] (5) A roller bearing, wherein

[0337] The roller bearing is used for a cylindrical roller bearing unit, the roller of the roller bearing is a cylindrical roller, the cylindrical roller bearing unit has: the roller bearing described in any one of (1) to (3); a pre-pressing portion that applies a constant pressure axial pre-pressing load to the outer ring or the inner ring; and a limiting portion that limits the axial movement of the inner ring or the outer ring that bears the pre-pressing load from the pre-pressing portion,

[0338] When the outer ring or the inner ring as the rotating ring of the roller bearing rotates, by applying a constant pressure axial pre-pressing load in a manner that the both end faces of all the rollers assembled in the roller bearing are always in contact with each of the flange portions, creaking sound is prevented.

[0339] According to the roller bearing, the edge load generated when the roller end face contacts the outer ring flange portion and the inner ring flange portion can be avoided, and abnormal heating is not generated. In addition, by applying the axial pre-pressing load, the movement of the cylindrical roller can be reliably limited, and the generation of creaking sound can be reliably prevented.

[0340] (6) The roller bearing according to (5), wherein

[0341] The connecting portion of the roller inclined surface and the chamfer portion is formed by a curved surface without an edge, and the axial pre-pressing load is applied to the side surface of one side of the outer ring and the side surface of the other side of the inner ring, that is, the side surface of one side of the outer ring and the side surface of the other side of the inner ring, to prevent creaking sound.

[0342] According to the roller bearing, edge collision between the roller end face and the guide surface is not generated, and the generation of sharp heating caused by edge load can be prevented.

[0343] (7) A roller bearing unit, wherein

[0344] The roller bearing described in (5) or (6); and

[0345] A limiting portion that limits the axial movement of the inner ring or the outer ring that bears the pre-pressing load from the pre-pressing portion,

[0346] When the outer ring or the inner ring as the rotating ring of the roller bearing rotates, by applying a constant pressure axial pre-pressing load that always contacts the both end faces of all the rollers assembled in the roller bearing with each of the flange portions, creaking sound is prevented.

[0347] According to the roller bearing unit, by the pre-pressing portion and the limiting portion, the axial pre-pressing load is correctly applied to the cylindrical roller bearing, and the axial movement is reliably limited. Therefore, there is no abnormal heating, and creaking sound can be prevented.

[0348] (8) An electric motor comprising:

[0349] a rotating shaft having a rotor;

[0350] a housing having a stator; and

[0351] (7) The roller bearing unit of the above (6), wherein the rotating shaft is rotatably supported by the housing.

[0352] According to the electric motor, it is possible to provide an electric motor that does not generate abnormal heat and noise during driving.

[0353] (9) A method of manufacturing a roller bearing including an outer ring having a raceway surface on an inner peripheral surface, an inner ring having a raceway surface on an outer peripheral surface, and a plurality of rollers disposed between the outer ring and the inner ring in a rotatable manner, wherein

[0354] a flange portion is provided on one or both of the outer ring and the inner ring, the flange portion protruding in a radial direction from the raceway surface, the flange portion having a guide surface that slides in contact with a roller end surface of the roller to guide the roller,

[0355] the roller has a chamfer portion formed at both axial ends of a roller outer peripheral surface, and a roller inclined surface provided at an axial end of the chamfer portion toward a roller inner diameter side of the roller end surface and facing the guide surface of the flange portion,

[0356] in a cross section obtained by cutting a surface including a rotating shaft of the roller and a bearing center axis, when a radial position of an end portion of the flange portion of the roller inclined surface opposite to the guide surface is set as a first position, a radial position of a boundary of the chamfer portion and the roller inclined surface is set as a second position, an intersection angle of a tangent line of the roller inclined surface at the first position and a perpendicular line of the rotating shaft of the roller is set as α, an intersection angle of a tangent line of the roller inclined surface at the second position and the perpendicular line of the rotating shaft of the roller is set as β, and an intersection angle of the guide surface and a perpendicular line of the bearing center axis is set as θ,

[0357] α < θ < β is satisfied.

[0358] According to the manufacturing method of the roller bearing, if the contact point of the flange portion guide surface and the roller end surface is the first position A, the roller end surface has a smaller inclination than the inclination of the guide surface, and thus the contact point does not move to the radial inner side of the roller than the first position A. In addition, if the contact point is the second position, the roller end surface has a larger inclination than the guide surface, and thus the contact point does not move to the radial outer side of the roller than the second position. Therefore, the contact point of the flange guide surface and the roller end surface falls within the range of the roller end surface from the first position to the second position. Thus, edge collision does not occur between the roller end surface and the guide surface, and generation of sharp heat due to edge load can be prevented. Thus, even when a large axial load is generated and deflection occurs, a higher axial resistance can be obtained. In addition, the clearance of the roller end surface and the guide surface is ensured, the supply of lubricant becomes good, and the cooling effect can be improved.

[0359] (10) A method of silencing a roller bearing, the roller bearing having an outer ring having a raceway surface on an inner peripheral surface, an inner ring having a raceway surface on an outer peripheral surface, and a plurality of cylindrical rollers disposed between the outer ring and the inner ring so as to be rotatable, wherein

[0360] the outer ring and the inner ring each have a flange portion provided so as to protrude in a radial direction from the raceway surface and having a guide surface that slides in contact with a roller end surface of the roller to guide the roller,

[0361] an axially constant pressure axial pre-load is applied to one side and the other side of the side surfaces of one side of the outer ring and the other side of the inner ring, and the axial pre-load is applied so that both end surfaces of all the rollers assembled in the roller bearing are always in contact with the respective flange portions when the outer ring or the inner ring, which is a rotation ring of the roller bearing, rotates.

[0362] According to the method of silencing the roller bearing, by applying the axial pre-load, the movement of the roller can be reliably restricted, and the generation of squeaking sound can be reliably prevented.

[0363] Thus, the present application is not limited to the above-described embodiments, and those skilled in the art will implement various structures of the embodiments in combination with each other or make changes and applications according to the description and publicly known technologies, which are within the scope of the present application.

[0364] In addition, the present application is based on Japanese Patent Application (Tokugan 2021-062261) filed on March 31, 2021, Japanese Patent Application (Tokugan 2021-062262) filed on March 31, 2021, the contents of which are incorporated herein by reference.

Claims

1. A roller bearing characterized by comprising: an outer ring having a raceway surface on an inner peripheral surface; an inner ring having a raceway surface on an outer peripheral surface; and a plurality of rollers disposed between the outer ring and the inner ring so as to be rollable, wherein a flange portion is formed in one or both of the outer ring and the inner ring, the flange portion is provided so as to protrude radially from the raceway surface, the flange portion has a guide surface that slides in contact with a roller end surface of the roller to guide the roller, the roller has a chamfer portion formed at both axial ends of a roller outer peripheral surface, and a roller inclined surface is provided from an axial end of the chamfer portion to a roller inner diameter side of the roller end surface and opposes the guide surface of the flange portion, in a cross section obtained by cutting a surface including a rotation axis of the roller and a bearing center axis, when a radial position of an end portion of the flange portion of the guide surface on a side of protrusion opposite the roller inclined surface is set as a first position, a radial position of a boundary of the chamfer portion and the roller inclined surface is set as a second position, an intersection angle of a tangent line of the roller inclined surface at the first position and a perpendicular line of the rotation axis of the roller is set as α, an intersection angle of a tangent line of the roller inclined surface at the second position and the perpendicular line of the rotation axis of the roller is set as β, and an intersection angle of the guide surface and a perpendicular line of the bearing center axis is set as θ, α < θ < β is satisfied.

2. The roller bearing according to claim 1, characterized in that an end portion of the guide surface on the raceway surface side is not formed with an axial direction extending grinding avoidance portion, and an axial direction extending grinding avoidance portion is formed at the end portion.

3. The roller bearing according to claim 1 or 2, characterized in that a surface roughness Ra of the guide surface is 0.1 μm or less.

4. The roller bearing according to claim 1 or 2, characterized in that the roller bearing is any one of a cylindrical roller bearing, a tapered roller bearing, a crossed roller bearing having cylindrical rollers, and a crossed tapered bearing having tapered rollers.

5. The roller bearing according to claim 3, characterized in that the roller bearing is any one of a cylindrical roller bearing, a tapered roller bearing, a crossed roller bearing having cylindrical rollers, and a crossed tapered bearing having tapered rollers.

6. A roller bearing unit characterized by comprising: the roller bearing according to any one of claims 1 to 3, the roller of the roller bearing being a cylindrical roller; a pre-pressing portion that applies a constant pressure axial pre-pressing load to the outer ring or the inner ring; and a restriction portion that restricts axial movement of the inner ring or the outer ring that receives the pre-pressing load from the pre-pressing portion, wherein when the outer ring or the inner ring that is a rotation ring of the roller bearing rotates, a creaking sound is prevented by applying a constant pressure axial pre-pressing load that causes both end surfaces of all the rollers assembled in the roller bearing to be in contact with each of the flange portions at all times. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 7. The roller bearing unit according to claim 6, characterized in that a connecting portion of the roller inclined surface and the chamfer portion is formed by a curved surface without an edge, and an axial pre-load is applied to one side surface of the outer ring and the other side surface of the inner ring, the one side surface of the outer ring and the other side surface of the inner ring being the side surface of the one side of the outer ring and the side surface of the other side of the inner ring, to prevent squeaking.

8. An electric motor characterized by provided with: a rotating shaft having a rotor; a housing having a stator; and the roller bearing unit according to claim 6 or 7, which rotatably supports the rotating shaft in the housing.

9. A manufacturing method of a roller bearing, characterized by the roller bearing is provided with: an outer ring having a raceway surface on an inner peripheral surface; an inner ring having a raceway surface on an outer peripheral surface; and a plurality of rollers disposed between the outer ring and the inner ring so as to be rotatable, a flange portion is provided on one or both of the outer ring and the inner ring, the flange portion protruding in a radial direction from the raceway surface, the flange portion having a guide surface that slides in contact with a roller end surface of the roller to guide the roller, the roller has: a chamfer portion formed on both axial ends of a roller outer peripheral surface; and a roller inclined surface provided from an axial end of the chamfer portion to a roller inner diameter side of the roller end surface, and opposed to the guide surface of the flange portion, in a cross section obtained by cutting a surface including a rotating shaft of the roller and a bearing center axis, when a radial position opposite to an end portion of the flange portion of the roller inclined surface on a protruding side of the guide surface is set as a first position, a radial position of a boundary of the chamfer portion and the roller inclined surface is set as a second position, an intersection angle of a tangent line of the roller inclined surface at the first position and a perpendicular line of the rotating shaft of the roller is set as a, an intersection angle of a tangent line of the roller inclined surface at the second position and the perpendicular line of the rotating shaft of the roller is set as β, and an intersection angle of the guide surface and a perpendicular line of the bearing center axis is set as θ, α < θ < β is satisfied.

10. A manufacturing method of a roller bearing, characterized by the roller bearing is provided with: an outer ring having a raceway surface on an inner peripheral surface; an inner ring having a raceway surface on an outer peripheral surface; and a plurality of rollers disposed between the outer ring and the inner ring so as to be rotatable, a flange portion is provided on one or both of the outer ring and the inner ring, the flange portion protruding in a radial direction from the raceway surface, the flange portion having a guide surface that slides in contact with a roller end surface of the roller to guide the roller, the roller has: a chamfer portion formed on both axial ends of a roller outer peripheral surface; and a roller inclined surface provided from an axial end of the chamfer portion to a roller inner diameter side of the roller end surface, and opposed to the guide surface of the flange portion, in a cross section obtained by cutting a surface including a rotating shaft of the roller and a bearing center axis, when a radial position opposite to an end portion of the flange portion of the roller inclined surface on a protruding side of the guide surface is set as a first position, a radial position of a boundary of the chamfer portion and the roller inclined surface is set as a second position, an intersection angle of a tangent line of the roller inclined surface at the first position and a perpendicular line of the rotating shaft of the roller is set as a, an intersection angle of a tangent line of the roller inclined surface at the second position and the perpendicular line of the rotating shaft of the roller is set as β, and an intersection angle of the guide surface and a perpendicular line of the bearing center axis is set as θ, α < θ < β is satisfied.

Images