Rolling bearing device

Abstract

To provide a rolling bearing device that can suppress temperature rise and running torque rise to lower levels when a rolling bearing device operates in a high-speed rotation range.SOLUTION: A rolling bearing device includes: an annular support wall part 12 for supporting an axial end face of an outer ring 5; and a nozzle wall part 13 extending on a radial inner side from the support wall part 12 so as to face a bearing space 7, where the nozzle wall part 13 includes an axle box 3 in which a nozzle hole 18 for jetting lubricant to the bearing space 7 is formed. The center line direction of the nozzle hole 18 is inclined in a travel direction of a rolling element 8 relative to an axial direction.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a rolling bearing device having a lubricant oil injection member that injects lubricant oil into a rolling bearing. [Background technology]

[0002] A known rolling bearing device having a lubricant injection member that injects lubricant into a rolling bearing is, for example, that disclosed in Patent Document 1. The rolling bearing device of Patent Document 1 has a rolling bearing having an outer ring, an inner ring arranged coaxially on the radial inside of the outer ring, and a plurality of rolling elements assembled at intervals in the circumferential direction in an annular bearing space formed between the inner circumference of the outer ring and the outer circumference of the inner ring, and an outer ring spacer (lubricant injection member) arranged adjacent to the rolling bearing.

[0003] The outer ring spacer has an annular support wall portion that supports the axial end face of the outer ring of the rolling bearing, and a nozzle wall portion that extends radially inward from the support wall portion so as to face the bearing space of the rolling bearing, and a nozzle hole that injects lubricating oil into the bearing space of the rolling bearing is formed in the nozzle wall portion. The nozzle hole is formed so that the center line direction of the nozzle hole is perpendicular to the traveling direction of the rolling elements. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2012-7681 A [Patent Document 2] Patent No. 4424293 Summary of the Invention [Problem to be solved by the invention]

[0005] The inventors of the present application faced the problem that the temperature and rotational torque of the rolling bearing (hereinafter simply referred to as "bearing") increased when the rolling bearing device configured as above was operated in the high-speed rotation range (specifically, in the rotation range where the dmn value (rotational speed x bearing pitch diameter) exceeds 500,000). When they investigated the cause of the increase in bearing temperature and rotational torque in the high-speed rotation range, they found that in the high-speed rotation range, the flow of lubricating oil injected into the bearing space from the nozzle holes in the outer ring spacer acts as resistance that impedes the movement of the rolling elements of the bearing, and that the resistance of this lubricating oil causes the bearing temperature to increase and the rotational torque to increase.

[0006] Therefore, in order to prevent the flow of lubricating oil sprayed from the nozzle holes from acting as resistance to the rolling elements, one possible method is to position an oil supply unit with a nozzle that drops lubricating oil into the bearing space adjacent to the bearing, as described in Patent Document 2, rather than spraying lubricating oil.However, when dripping lubricating oil, it is difficult to sufficiently cool the contact points between the rolling elements and the inner ring, and it is not possible to prevent the bearing temperature from rising in the high-speed rotation range.

[0007] An object of the present invention is to provide a rolling bearing device capable of suppressing increases in temperature and rotational torque during operation in a high speed rotation range. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention provides a rolling bearing device having the following configuration. [Configuration 1] a rolling bearing including an outer ring, an inner ring arranged coaxially on the radially inner side of the outer ring, and a plurality of rolling elements assembled at intervals in the circumferential direction in an annular bearing space formed between an inner periphery of the outer ring and an outer periphery of the inner ring; a lubricant oil injection member having an annular support wall portion supporting an axial end face of the outer ring, and a nozzle wall portion extending radially inward from the support wall portion so as to face the bearing space, the nozzle wall portion having a nozzle hole formed therein for injecting lubricant oil into the bearing space, A rolling bearing device, characterized in that a center line direction of the nozzle hole is inclined with respect to an axial direction toward a direction in which the rolling elements move.

[0009] With this configuration, the center line of the nozzle hole is inclined toward the direction of movement of the rolling elements, so the flow of lubricating oil injected from the nozzle hole is less likely to create resistance that impedes the movement of the rolling elements, making it possible to keep the temperature rise and rotational torque rise of the rolling bearing low when operating in the high-speed rotation range.

[0010] [Configuration 2] An inner ring raceway surface with which the rolling elements roll and contact is formed on an outer periphery of the inner ring, 2. The rolling bearing device according to claim 1, wherein the inner ring raceway surface is located on an extension of a center line of the nozzle hole.

[0011] By adopting this configuration, it is possible to effectively cool the contact points between the rolling elements and the inner ring, which are the parts of the rolling bearing that are most susceptible to heat generation.

[0012] [Configuration 3] 3. The rolling bearing device according to configuration 1 or 2, wherein an inclination angle of the center line direction of the nozzle hole in the direction of movement of the rolling elements with respect to an axial direction is set to be equal to or greater than 20° and equal to or less than 70°.

[0013] When this configuration is adopted, the inclination angle of the center line direction of the nozzle hole to the moving direction of the rolling element is set to 20° or more, so that the flow of lubricating oil sprayed from the nozzle hole can be effectively suppressed from becoming a resistance to the movement of the rolling element. Also, the inclination angle of the center line direction of the nozzle hole to the moving direction of the rolling element is set to 70° or less, so that the distance from when the lubricating oil is sprayed from the nozzle hole to when it hits the lubricating point inside the rolling bearing is kept short, and the lubricating oil sprayed from the nozzle hole is less likely to spread. Therefore, it is possible to reliably hit the lubricating point inside the rolling bearing with the lubricating oil.

[0014] [Configuration 4] 4. The rolling bearing device according to any one of configurations 1 to 3, wherein the nozzle wall portion is provided with a plurality of the nozzle holes spaced apart from one another in the circumferential direction.

[0015] By adopting this configuration, it becomes possible to cool the inside of the rolling bearing particularly effectively.

[0016] [Configuration 5] 5. The rolling bearing device according to any one of configurations 1 to 4, wherein the nozzle hole is a hole having an inner diameter of 1.0 mm or more and 2.0 mm or less and a round cross section.

[0017] By adopting this configuration, the flow rate of the lubricating oil injected from the nozzle hole can be increased compared to the case of using a nozzle hole with an inner diameter exceeding 2.0 mm, and the flow rate of the lubricating oil injected from the nozzle hole can be made close to the moving speed of the rolling elements of the rolling bearing. Therefore, it is possible to effectively suppress the temperature rise and the increase in the rotational torque of the rolling bearing when operating in the high speed rotation range. In addition, if the diameter is less than 1.0 mm, the supply pressure of the lubricating oil increases, which increases the load on the lubricating oil supply device such as the oil pump, and there is a risk of damage to the lubricating oil supply device or insufficient supply of lubricating oil.

[0018] [Configuration 6] a center line direction of the nozzle hole is inclined with respect to an axial direction in a direction in which the rolling elements move and is also inclined radially inward, a bottomed hole having a bottom surface that is a plane perpendicular to a center line direction of the nozzle hole is formed in the nozzle wall portion, 6. The rolling bearing device according to any one of configurations 1 to 5, wherein the nozzle hole opens into the bottom surface of the blind hole.

[0019] When this configuration is adopted, the center line direction of the nozzle hole is inclined toward the moving direction of the rolling body and also inclined inward in the radial direction, so that the flow of lubricating oil injected from the nozzle hole can effectively lubricate the outer periphery of the inner ring while suppressing the resistance of the movement of the rolling body. In addition, a bottomed hole is formed in the nozzle wall portion, the bottom surface of which is a plane perpendicular to the center line direction of the nozzle hole, and the nozzle hole opens into the bottom surface of the bottomed hole, so that the lubricating oil can be stably supplied to the lubrication point on the outer periphery of the inner ring. In other words, when the center line direction of the nozzle hole is inclined toward the moving direction of the rolling body and also inclined inward in the radial direction, it is possible to simply open the nozzle hole on the surface of the nozzle wall portion, but in that case, the shape of the end opening of the nozzle hole becomes an ellipse whose major axis is inclined with respect to the center line direction of the nozzle hole, so that the injection pressure of the lubricating oil is biased inside the end opening of the nozzle hole, and the lubricating oil cannot be injected uniformly along the center line of the nozzle hole, which may cause the supply of the lubricating oil to the lubrication point on the outer periphery of the inner ring to become unstable. In contrast, if a bottomed hole whose bottom surface is a plane perpendicular to the center line direction of the nozzle hole is formed in the nozzle wall portion and the nozzle hole is opened at the bottom surface of the bottomed hole, the shape of the end opening of the nozzle hole will be a perfect circle perpendicular to the center line direction of the nozzle hole, preventing bias in the injection pressure of the lubricating oil inside the end opening of the nozzle hole. This allows the lubricating oil to be injected uniformly along the center line of the nozzle hole, making it possible to stably supply the lubricating oil to the lubrication point on the outer periphery of the inner ring.

[0020] [Configuration 7] an air nozzle hole for injecting compressed air into the bearing space is formed in the nozzle wall portion at a position circumferentially spaced from the nozzle hole; 7. The rolling bearing device according to any one of configurations 1 to 6, wherein a center line direction of the air nozzle hole is inclined with respect to an axial direction toward a direction in which the rolling elements move.

[0021] By adopting this configuration, the inside of the rolling bearing can be cooled by the compressed air injected from the air nozzle hole, so the amount of lubricating oil injected from the nozzle hole can be reduced accordingly, and the rotational torque of the bearing can be reduced due to the reduced consumption of lubricating oil. Also, since the center line direction of the air nozzle hole is inclined with respect to the axial direction in the direction of travel of the rolling elements, it is possible to prevent the compressed air injected from the air nozzle hole from hitting the lubricating oil located in front of the rolling elements in the direction of travel, thereby preventing a reduction in the amount of lubricating oil in front of the rolling elements in the direction of travel, and it is possible to maintain a good lubricated state inside the rolling bearing.

[0022] [Configuration 8] A second nozzle hole that injects lubricating oil into the bearing space is formed in the nozzle wall at a position circumferentially spaced from the nozzle hole, a center line direction of the second nozzle hole is inclined in a direction opposite to a moving direction of the rolling element with respect to an axial direction, A rolling bearing device according to any one of configurations 1 to 7, further comprising a switching valve that can switch between a state in which lubricating oil is supplied only to the nozzle hole and a state in which lubricating oil is supplied only to the second nozzle hole, out of the nozzle hole and the second nozzle hole.

[0023] By adopting this configuration, it is possible to keep the temperature rise of the rolling bearing and the increase in rotational torque low even when the rotation direction is switched to reverse rotation. Effect of the Invention

[0024] In the rolling bearing device of this invention, the center line direction of the nozzle hole is inclined to the direction of movement of the rolling elements, so the flow of lubricating oil injected from the nozzle hole is less likely to create resistance that impedes the movement of the rolling elements, making it possible to keep the temperature rise and rotational torque rise of the rolling bearing low when operating in the high speed rotation range. [Brief description of the drawings]

[0025] [Figure 1] FIG. 1 is a cross-sectional view showing a rolling bearing device according to a first embodiment of the present invention. [Diagram 2]FIG. 2 is a view of the axle housing of the rolling bearing device shown in FIG. 1, seen from the rolling bearing side. [Diagram 3] Enlarged view of the nozzle hole and its surroundings in Figure 2 [Figure 4] Enlarged view of the nozzle hole and its surroundings in Figure 1 [Diagram 5] Cross-sectional view taken along line VV in Figure 4. [Figure 6] FIG. 2 shows a second embodiment of the present invention. [Figure 7] FIG. 3 is a diagram showing a third embodiment of the present invention, corresponding to FIG. 2. [Figure 8] An enlarged view of the nozzle hole and the second nozzle hole of FIG. 7 , and their vicinity. [Figure 9] FIG. 1 shows the relationship between the rotation speed and temperature of a rolling bearing when a rolling bearing device according to an embodiment in which the center line direction of a nozzle hole is inclined to the moving direction of the rolling element and a rolling bearing device according to a comparative example in which the center line direction of a nozzle hole is perpendicular to the moving direction of the rolling element are rotated at high speed. [Figure 10] FIG. 1 shows the relationship between the rotational speed and the rotational torque of a rolling bearing when a rolling bearing device according to an embodiment in which the center line direction of a nozzle hole is inclined to the moving direction of the rolling element, and a rolling bearing device according to a comparative example in which the center line direction of a nozzle hole is oriented perpendicular to the moving direction of the rolling element, are rotated at high speed. [Figure 11] FIG. 7 shows the relationship between the rotation speed and temperature of the rolling bearing when the rolling bearing device is rotated at high speed under the condition that lubricating oil is injected from the nozzle hole shown in FIG. 6 and injection is stopped from the air nozzle hole, and the relationship between the rotation speed and temperature of the rolling bearing when the rolling bearing device is rotated at high speed under the condition that lubricating oil is injected from the nozzle hole shown in FIG. 6 and compressed air is injected from the air nozzle hole. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Fig. 1 shows a rolling bearing device according to a first embodiment of the present invention. This rolling bearing device has a rolling bearing 2 that rotatably supports a rotating shaft 1, and an axle box 3 that houses the rolling bearing 2. The rotating shaft 1 is a shaft that is driven by a prime mover (electric motor, engine, etc.) not shown. The axle box 3 is fixed to a housing 4 with bolts not shown.

[0027] The rolling bearing 2 has an outer ring 5, an inner ring 6 arranged coaxially on the radial inside of the outer ring 5, a plurality of rolling elements 8 assembled at intervals in the circumferential direction in an annular bearing space 7 formed between the inner circumference of the outer ring 5 and the outer circumference of the inner ring 6, and a cage 9 for holding the plurality of rolling elements 8. Openings at both axial ends of the bearing space 7 sandwiched between the inner circumference of the outer ring 5 and the outer circumference of the inner ring 6 are left open and not sealed with a seal member or the like. The axial direction is parallel to the central axis of the rolling bearing 2 (i.e., parallel to the central axis of the inner ring 6 or the outer ring 5). The inner ring 6 is fitted onto the outer circumference of the rotating shaft 1 with interference.

[0028] 4, the axle box 3 has a cylindrical portion 10 that fits onto the outer periphery of the outer ring 5, and an inward flange 11 that extends radially inward from one axial end of the cylindrical portion 10. The inward flange 11 has an annular support wall portion 12 that supports the axial end face of the outer ring 5, and an annular nozzle wall portion 13 that extends radially inward from the support wall portion 12 so as to face the bearing space 7.

[0029] The outer periphery of the outer ring 5 is fitted with a gap in the inner periphery of the cylindrical portion 10 of the axle box 3. The rolling elements 8 are balls here. The inner periphery of the outer ring 5 is provided with an outer ring raceway surface 14 with an arcuate cross section with which the rolling elements 8 roll. The outer periphery of the inner ring 6 is provided with an inner ring raceway surface 15 with an arcuate cross section with which the rolling elements 8 roll. The inner ring 6 is a shouldered inner ring in which the inner ring shoulder on the side closer to the nozzle wall portion 13 and the inner ring shoulder 16 on the side farther from the nozzle wall portion 13 are removed to form an inner ring counterbore portion 17, with respect to the inner ring raceway surface 15 with which the rolling elements 8 roll. This rolling bearing 2 is an angular ball bearing in which the straight line connecting the contact point between the inner ring 6 and the rolling elements 8 and the contact point between the outer ring 5 and the rolling elements 8 is inclined so as to move away from the nozzle wall portion 13 in the axial direction from the radially inner side to the radially outer side.

[0030] The nozzle wall portion 13 is formed with a nozzle hole 18 for injecting lubricating oil into the bearing space 7. The nozzle hole 18 is a hole with a round cross section that extends straight through the inside of the nozzle wall portion 13 in the center line direction of the nozzle hole 18. The nozzle hole 18 has a constant inner diameter along the center line direction of the nozzle hole 18. The inner diameter of the nozzle hole 18 is set to a size of 1.0 mm or more and 2.0 mm or less. One end of the nozzle hole 18 opens so as to inject lubricating oil toward the bearing space 7, and the other end of the nozzle hole 18 is connected to an oil supply hole 19 that extends radially through the inside of the support wall portion 12 and the inside of the nozzle wall portion 13. The oil supply hole 19 has a cross-sectional area five times or more the cross-sectional area of ​​the nozzle hole 18.

[0031] As shown in FIG. 1, the oil supply hole 19 communicates with an oil hole 20 formed in the housing 4. The oil hole 20 is supplied with lubricating oil pumped from an oil pump (not shown). Here, it is possible to supply only the lubricating oil to the oil hole 20 so that only the lubricating oil is sprayed from the nozzle hole 18 (jet lubrication), but it is also possible to supply the lubricating oil mixed with compressed air to the oil hole 20 so that the lubricating oil is sprayed from the nozzle hole 18 together with the compressed air (air-oil lubrication). The lubricating oil may have a viscosity of VG2 to VG32 according to the ISO viscosity grade number. A lubricating oil discharge pump (not shown) is provided in a space connected to the opening on the side far from the nozzle wall portion 13 of the bearing space 7, which draws in air from the bearing space 7 and forcibly discharges the lubricating oil that has passed through the bearing space 7.

[0032] As shown in Fig. 2, a plurality of nozzle holes 18 (four in the figure) are provided at equal intervals in the circumferential direction. As shown in Figs. 4 and 5, the center line direction of each nozzle hole 18 is inclined toward the moving direction of the rolling elements 8 with respect to the axial direction, and is also inclined radially inward. When the bearing rotates in both forward and reverse directions (i.e., there are times when the rolling elements 8 move in one circumferential direction and times when they move in the other circumferential direction), it is preferable to incline the center line direction of each nozzle hole 18 toward the moving direction of the rolling elements 8 corresponding to the rotation direction of the bearing that is used most frequently, since this effectively reduces temperature rise and rotational torque.

[0033] As shown in Figure 5, the inclination angle of the center line direction of the nozzle hole 18 in the direction of travel of the rolling body 8 with respect to the axial direction (the inclination angle of the center line of the nozzle hole 18 with respect to the axial direction when viewed from the radial direction (the up-down direction in the figure)) is set to 20° or more and 70° or less (preferably 30° or more and 60° or less).

[0034] As shown in FIG. 4, the nozzle hole 18 is inclined radially inward with respect to the axial direction (horizontal direction in the drawing) so that the inner ring raceway surface 15 is located on the extension line of the center line of the nozzle hole 18. In the drawing, the nozzle hole 18 is formed so that the extension line of the center line of the nozzle hole 18 intersects with the position (the position of the raceway diameter) where the outer diameter of the inner ring raceway surface 15 is the smallest. It is also possible to form the nozzle hole 18 so that the extension line of the center line of the nozzle hole 18 intersects with the inner ring counterbore portion 17 formed on the side closer to the nozzle wall portion 13 than the inner ring raceway surface 15. The side surface of the nozzle wall portion 13 facing the rolling bearing 2 is a tapered surface 21 that is inclined radially inward and gradually moves away from the bearing space 7. The tapered surface 21 is inclined so as to be perpendicular to the center line of the nozzle hole 18 when viewed from the circumferential direction as shown in FIG. 4 (i.e., the inclination angle of the center line of the nozzle hole 18 radially inward with respect to the axial direction is the same as the inclination angle of the tapered surface 21 with respect to the axis-perpendicular direction).

[0035] 3 to 5, a bottomed hole 23 is formed in the tapered surface 21, the bottom surface 22 of which is a plane perpendicular to the center line direction of the nozzle hole 18. The bottomed hole 23 is a circular hole with a larger diameter than the nozzle hole 18, and the nozzle hole 18 opens into the bottom surface 22 of the bottomed hole 23.

[0036] 5, in this rolling bearing device, the center line direction of the nozzle hole 18 is inclined toward the traveling direction of the rolling elements 8, so that the flow of lubricating oil injected from the nozzle hole 18 is less likely to create resistance that impedes the movement of the rolling elements 8. This makes it possible to keep low the temperature rise and rotational torque rise of the rolling bearing 2 when operating in the high-speed rotation range (specifically, the rotation range where the dmn value (rotational speed × bearing pitch diameter) exceeds 500,000).

[0037] Furthermore, as shown in Figure 4, in this rolling bearing device, the inner ring raceway surface 15 is located on the extension of the center line of the nozzle hole 18, making it possible to effectively cool the contact point between the rolling element 8 and the inner ring 6, which is the part of the rolling bearing 2 that is most susceptible to heat generation.

[0038] 5, the inclination angle of the nozzle hole 18 in the center line direction to the traveling direction of the rolling element 8 is set to 20° or more (preferably 30° or more), so that the flow of lubricating oil injected from the nozzle hole 18 can be effectively prevented from becoming a resistance to the movement of the rolling element 8. Also, the inclination angle of the nozzle hole 18 in the center line direction to the traveling direction of the rolling element 8 is set to 70° or less (preferably 60° or more), so that the distance from when the lubricating oil is injected from the nozzle hole 18 to when it hits the lubricating point inside the rolling bearing 2 is kept short, and the lubricating oil injected from the nozzle hole 18 is less likely to spread. Therefore, it is possible to reliably apply the lubricating oil to the lubricating point inside the rolling bearing 2.

[0039] In addition, since this rolling bearing device has a plurality of nozzle holes 18 spaced apart in the circumferential direction as shown in FIG. 2, it is possible to particularly effectively cool the inside of the rolling bearing 2 shown in FIG. 4.

[0040] In addition, this rolling bearing device employs a round hole with an inner diameter of 1.0 mm or more and 2.0 mm or less as the nozzle hole 18 shown in FIG. 4, so that the flow rate of the lubricating oil injected from the nozzle hole 18 can be increased compared to the case where a nozzle hole 18 with an inner diameter exceeding 2.0 mm is employed, and the flow rate of the lubricating oil injected from the nozzle hole 18 can be made close to the moving speed of the rolling elements 8 of the rolling bearing 2. Therefore, the temperature rise and the rotational torque rise of the rolling bearing 2 when operating in the high speed rotation range can be effectively suppressed. Note that if the diameter falls below 1.0 mm, the supply pressure of the lubricating oil increases, which increases the load on the lubricating oil supply device such as the oil pump, and there is a risk of damage to the lubricating oil supply device or insufficient supply of lubricating oil.

[0041] 3 to 5, in this rolling bearing device, a bottomed hole 23 having a bottom surface 22 that is a plane perpendicular to the center line direction of the nozzle hole 18 is formed in the nozzle wall portion 13, and the nozzle hole 18 opens into the bottom surface 22 of the bottomed hole 23, so that it is possible to stably supply lubricating oil to lubrication points on the outer periphery of the inner ring 6. That is, when the center line direction of the nozzle hole 18 is inclined toward the traveling direction of the rolling elements 8 as shown in FIG. 5 and also inclined radially inward as shown in FIG. 4, it is also possible to simply open the nozzle hole 18 into the tapered surface 21, but in that case, the shape of the end opening of the nozzle hole 18 becomes an ellipse whose major axis is in the direction inclined with respect to the center line direction of the nozzle hole 18, so that the injection pressure of the lubricating oil is biased inside the end opening of the nozzle hole 18, and the lubricating oil cannot be injected uniformly along the center line of the nozzle hole 18, which may result in unstable supply of lubricating oil to lubrication points on the outer periphery of the inner ring 6. 3 to 5, if a bottomed hole 23 having a bottom surface 22 that is a plane perpendicular to the center line direction of the nozzle hole 18 is formed in the tapered surface 21 of the nozzle wall portion 13, and the nozzle hole 18 is opened at the bottom surface 22 of the bottomed hole 23, the shape of the end opening of the nozzle hole 18 will be a perfect circle perpendicular to the center line direction of the nozzle hole 18, preventing bias in the injection pressure of the lubricating oil from occurring inside the end opening of the nozzle hole 18. As a result, the lubricating oil can be injected uniformly along the center line of the nozzle hole 18, making it possible to stably supply the lubricating oil to the lubrication points on the outer periphery of the inner ring 6.

[0042] A second embodiment of the present invention is shown in Fig. 6. Parts corresponding to those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

[0043] The nozzle wall portion 13 is formed with a plurality of nozzle holes 18 (two in the figure) at equal intervals in the circumferential direction. The nozzle wall portion 13 is also formed with a plurality of air nozzle holes 24 (two in the figure) at positions circumferentially spaced from the nozzle holes 18 for injecting compressed air into the bearing space 7 (see FIG. 4). Each air nozzle hole 24 is disposed at a midpoint between the nozzle holes 18 adjacent in the circumferential direction. The center line direction of the air nozzle hole 24 is inclined toward the moving direction of the rolling element 8 with respect to the axial direction and also inclined radially inward. The tapered surface 21 of the nozzle wall portion 13 is formed with a bottomed hole 26 having a bottom surface 25 that is a plane perpendicular to the center line direction of the air nozzle hole 24, and the air nozzle hole 24 opens at the bottom surface 25 of the bottomed hole 26. Each air nozzle hole 24 is connected to an air supply hole 27 extending in the radial direction. Compressed air sent from an air compressor (not shown) is supplied to the air supply hole 27.

[0044] In the rolling bearing device of the second embodiment, the inside of the rolling bearing 2 shown in Fig. 4 can be cooled by compressed air injected from the air nozzle holes 24, so that the amount of lubricating oil injected from the nozzle holes 18 can be reduced accordingly, and a reduction in the rotational torque of the bearing can be expected due to the reduction in the amount of lubricating oil consumed. In addition, because the center line direction of the air nozzle holes 24 is inclined relative to the axial direction in the traveling direction of the rolling elements 8, it is possible to prevent the compressed air injected from the air nozzle holes 24 from hitting the lubricating oil located ahead of the rolling elements 8 in the traveling direction, thereby preventing a reduction in the lubricating oil ahead of the rolling elements 8 in the traveling direction, and the inside of the rolling bearing 2 can be kept in a good lubricated state.

[0045] A third embodiment of the present invention is shown in Figures 7 and 8. The parts corresponding to those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

[0046] As shown in Fig. 7, the nozzle wall portion 13 is formed with a plurality of second nozzle holes 28 (four in the figure) at positions circumferentially spaced from the nozzle hole 18, which inject lubricating oil into the bearing space 7. As shown in Fig. 8, the center line direction of the second nozzle holes 28 is inclined in the opposite direction to the traveling direction of the rolling elements 8 with respect to the axial direction. The second nozzle holes 28 are connected to a second oil supply hole 29 extending in the radial direction. The configuration of the second nozzle holes 28 and their periphery is the same as that of the nozzle hole 18 and its periphery, and is circumferentially symmetrical.

[0047] 7, an oil supply path 30 is connected to the plurality of oil supply holes 19, and a second oil supply path 31 is connected to the plurality of second oil supply holes 29. The oil supply path 30 and the second oil supply path 31 are connected to an oil pump 33 via a changeover valve 32. The changeover valve 32 is an electromagnetic control valve that can be electrically switched between a state in which the oil pump 33 communicates with the oil supply path 30 and the oil pump 33 communicates with the second oil supply path 31 to supply lubricating oil only to the nozzle hole 18, and a state in which the oil pump 33 communicates with the oil supply path 30 and the oil pump 33 communicates with the second oil supply path 31 to supply lubricating oil only to the second nozzle hole 28.

[0048] In the rolling bearing device of the third embodiment, when the rotating shaft 1 shown in Fig. 1 is rotated in the forward direction, the lubricating oil is injected only from the nozzle hole 18 out of the nozzle hole 18 and the second nozzle hole 28 by operating the changeover valve 32 shown in Fig. 7, and when the rotating shaft 1 shown in Fig. 1 is rotated in the reverse direction, the lubricating oil is injected only from the second nozzle hole 28 out of the nozzle hole 18 and the second nozzle hole 28 by operating the changeover valve 32 shown in Fig. 7. In this way, even when the rotation direction is switched to reverse rotation for use, it is possible to keep the temperature rise and rotational torque rise of the rolling bearing 2 shown in Fig. 1 low.

[0049] In order to confirm that tilting the center line direction of the nozzle hole 18 toward the traveling direction of the rolling elements 8 with respect to the axial direction can suppress the increase in temperature and rotational torque of the rolling bearing 2 during operation in the high-speed rotation range, a rolling bearing device of the embodiment in which the center line direction of the nozzle hole 18 is tilted at 45° toward the traveling direction of the rolling elements 8 with respect to the axial direction as viewed from the radial direction, and a rolling bearing device of the comparative example in which the center line direction of the nozzle hole 18 is oriented perpendicular to the traveling direction of the rolling elements 8 as viewed from the radial direction were prepared, and these rolling bearing devices were rotated at high speed and tests were conducted to measure the temperatures of the inner ring 6 and outer ring 5 at each rotation speed and the rotational torque of the inner ring 6 at each rotation speed. The test results are shown in Figures 9 and 10.

[0050] As shown in Fig. 9, in the high speed rotation range where the bearing dmn value is 500,000 or more, it can be confirmed that the temperatures of the inner ring 6 and outer ring 5 of the example (the dashed line graph in the figure) are lower than the temperatures of the inner ring 6 and outer ring 5 of the comparative example (the solid line graph in the figure). Also, as shown in Fig. 10, it can be confirmed that in the high speed rotation range where the bearing dmn value is 500,000 or more, the rotation torque of the inner ring 6 of the example is reduced by about 20% compared to the rotation torque of the inner ring 6 of the comparative example.

[0051] Furthermore, in order to confirm that it is possible to cool the inside of the rolling bearing 2 by injecting compressed air from the air nozzle hole 24 shown in Fig. 6, tests were conducted to measure the temperatures of the inner ring 6 and the outer ring 5 when the rolling bearing device was rotated at high speed with lubricating oil being injected from the nozzle hole 18 shown in Fig. 6 and injection from the air nozzle hole 24 stopped, and the temperatures of the inner ring 6 and the outer ring 5 when the rolling bearing device was rotated at high speed with lubricating oil being injected from the nozzle hole 18 shown in Fig. 6 and compressed air being injected from the air nozzle hole 24. The test results are shown in Fig. 11.

[0052] As shown in Figure 11, it can be confirmed that the temperature of the inner ring 6 and the outer ring 5 when the rolling bearing device is rotated at high speed with compressed air being injected from the air nozzle hole 24 (the dashed line graph in the figure) is significantly lower than the temperature of the inner ring 6 and the outer ring 5 when the rolling bearing device is rotated at high speed with injection from the air nozzle hole 24 stopped (the solid line graph in the figure).

[0053] In each of the above embodiments, as shown in FIG. 1 , the axle box 3 that houses the rolling bearing 2 has been described as an example of a lubricant injection member having a nozzle hole 18 that injects lubricant oil into the bearing space 7. However, an outer ring spacer that has the same outer diameter as the outer ring 5 and is arranged axially adjacent to the outer ring 5 may also be used as the lubricant injection member.

[0054] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0055] 2. Rolling bearings 3 Axle box (lubricating oil injection part) 5 Outer ring 6. Inner Circle 7 Bearing space 8 Rolling elements 12 Support wall section 13 Nozzle wall 15 Inner ring raceway 18 Nozzle hole 22 Bottom 23 Bottomed hole 24 Air nozzle hole 28 Second nozzle hole 32 Switching valve

Claims

1. a rolling bearing (2) having an outer ring (5), an inner ring (6) arranged coaxially on the radially inner side of the outer ring (5), and a plurality of rolling elements (8) assembled at intervals in the circumferential direction in an annular bearing space (7) formed between an inner periphery of the outer ring (5) and an outer periphery of the inner ring (6); a lubricant oil injection member (3) having an annular support wall portion (12) supporting an axial end face of the outer ring (5) and a nozzle wall portion (13) extending radially inward from the support wall portion (12) so as to face the bearing space (7), the nozzle wall portion (13) having a nozzle hole (18) formed therein for injecting lubricant oil into the bearing space (7), A rolling bearing device, characterized in that the center line direction of the nozzle hole (18) is inclined with respect to the axial direction toward the traveling direction of the rolling element (8).

2. An inner ring raceway surface (15) with which the rolling elements (8) roll and contact is formed on the outer periphery of the inner ring (6), 2. The rolling bearing device according to claim 1, wherein the inner ring raceway surface (15) is located on an extension line of a center line of the nozzle hole (18).

3. 3. The rolling bearing device according to claim 1, wherein an inclination angle of the nozzle hole (18) in the direction of travel of the rolling element (8) with respect to an axial direction of a center line of the nozzle hole (18) is set to be 20° or more and 70° or less.

4. 3. The rolling bearing device according to claim 1, wherein a plurality of the nozzle holes (18) are provided in the nozzle wall portion (13) at intervals in the circumferential direction.

5. 3. The rolling bearing device according to claim 1, wherein the nozzle hole (18) is a hole having an inner diameter of 1.0 mm or more and 2.0 mm or less and a round cross section.

6. The center line direction of the nozzle hole (18) is inclined toward the moving direction of the rolling element (8) with respect to the axial direction and is also inclined radially inward, A bottomed hole (23) having a bottom surface (22) that is a plane perpendicular to the center line direction of the nozzle hole (18) is formed in the nozzle wall portion (13), 3. The rolling bearing device according to claim 1, wherein the nozzle hole (18) opens into the bottom surface (22) of the blind hole (23).

7. An air nozzle hole (24) for injecting compressed air into the bearing space (7) is formed in the nozzle wall portion (13) at a position circumferentially spaced from the nozzle hole (18), 3. The rolling bearing device according to claim 1, wherein the center line direction of the air nozzle hole (24) is inclined with respect to the axial direction in the direction of movement of the rolling elements (8).

8. A second nozzle hole (28) for injecting lubricating oil into the bearing space (7) is formed in the nozzle wall portion (13) at a position circumferentially spaced from the nozzle hole (18), The center line direction of the second nozzle hole (28) is inclined in the opposite direction to the moving direction of the rolling element (8) with respect to the axial direction, 3. The rolling bearing device according to claim 1 or 2, further comprising a switching valve (32) capable of switching between a state in which lubricating oil is supplied only to the nozzle hole (18) and a state in which lubricating oil is supplied only to the second nozzle hole (28).

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