Bearing device and mechanical device

Abstract

To provide a bearing device which enables smooth supply of a lubrication oil to a rolling unit without increase in size of the facility, and to provide a mechanical device.SOLUTION: A bearing device includes: a bearing 11; and a lubrication oil supply unit 20 for supplying a lubrication oil. The bearing 11 includes a plurality of rolling elements 15 and a retainer 16 for retaining the rolling elements 15. The retainer 16 has a retainer inner diameter surface 16b. The lubrication oil supply unit 20 includes: a retaining part which retains the lubrication oil to be supplied to the interior of the bearing 11; and a nozzle member 37 which supplies the lubrication oil from the retaining part to the inside of the bearing 11. The nozzle member 37 has an apical surface 37b. The apical surface 37b is a flat surface for the lubrication oil to form oil droplets toward the retainer inner diameter surface 16b.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a bearing device and a mechanical device. [Background technology]

[0002] Japanese Patent No. 6054095 (Patent Document 1) and Japanese Patent No. 6750296 (Patent Document 2) disclose bearing devices that combine rolling bearings with a lubricating oil supply unit (lubricating oil supply mechanism). In these documents, the lubricating oil is drawn from a tank attached to the lubricating oil supply unit. In these disclosed technologies, the tank is either a bag type, a casing type, or a type equipped with a porous body that retains the lubricating oil within the casing.

[0003] In addition, Japanese Patent No. 6599626 (Patent Document 3) proposes to devise an orientation angle of a long and narrow nozzle that supplies lubricating oil discharged from a lubricating oil supply unit to the bearing side. Furthermore, in the technology disclosed in Japanese Patent No. 6495700 (Patent Document 4), the nozzle is not long and narrow, but is a block or ring-shaped member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6054095 [Patent Document 2] Patent No. 6750296 [Patent Document 3] Patent No. 6599626 [Patent Document 4] Patent No. 6495700 Summary of the Invention [Problem to be solved by the invention]

[0005] Lubricating oil must reach the rolling contact areas of the bearing. The rolling contact areas are the boundaries between the rolling elements and the raceway surface, and between the rolling elements and the cage. If the lubricating oil does not reach the rolling contact areas, the bearing will heat up significantly. This temperature rise will cause damage to the cage and wear to the raceway surface. According to the techniques disclosed in the above documents, there is a risk that the lubricating oil discharged from the lubricating oil supply unit will be repelled by the swirling flow caused by the rotation of the bearing and will not reach the rolling contact areas. To solve the above problem, it is possible to use a high-output oil supply pump or a large lubricating oil tank. However, this would result in an increase in the size of the bearing device, which would make it unsuitable for use in small machines.

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a bearing device and a mechanical device that can smoothly supply lubricating oil to the rolling contact parts without increasing the size of the equipment. [Means for solving the problem]

[0007] A bearing device according to one embodiment of the present disclosure includes a bearing and a lubricant supply unit that supplies lubricant to the bearing. The bearing includes a plurality of rolling elements and a cage. The plurality of rolling elements are arranged side by side on an annular raceway. The cage holds the plurality of rolling elements. The cage has a cage inner diameter surface formed on the inner diameter side in the radial direction. The lubricant supply unit includes a holding portion and a nozzle member. The holding portion holds lubricant to be supplied to the inside of the bearing. The nozzle member supplies lubricant from the holding portion to the inside of the bearing. The nozzle member has a tip surface. The tip surface is a flat surface that allows the lubricant to form oil droplets toward the cage inner diameter surface.

[0008] A mechanical device according to one embodiment of the present disclosure includes a rotating shaft, a housing, and the bearing device. The housing is disposed on the outer periphery of the rotating shaft. The bearing device rotatably supports the rotating shaft relative to the housing. [Effects of the Invention]

[0009] According to the above, it is possible to provide a bearing device and a mechanical device that can smoothly supply lubricating oil to the rolling contact portion without increasing the size of the equipment. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic side view of a bearing device according to an embodiment of the present invention; [Figure 2] 2 is a cross-sectional view of a portion taken along line AA in FIG. 1 according to the first embodiment. [Figure 3] FIG. 3 is an enlarged schematic cross-sectional view of a region III surrounded by a dotted line in FIG. 2. [Figure 4] 2 is a schematic perspective view of a circular ring-shaped nozzle member according to the first embodiment. FIG. [Figure 5] 5 is an enlarged perspective schematic view of a first example of an area B surrounded by a dotted line in FIG. 4. FIG. [Figure 6] 6 is a perspective schematic diagram showing an area on the arrow side of line segment VI-VI in FIG. 5 in a further enlarged scale than FIG. 5. FIG. [Figure 7] 5 is an enlarged perspective schematic view of a second example of an area B surrounded by a dotted line in FIG. 4. FIG. [Figure 8] 5 is an enlarged perspective schematic view of a third example of an area B surrounded by a dotted line in FIG. 4. FIG. [Figure 9] 5 is an enlarged perspective schematic view of a fourth example of an area B surrounded by a dotted line in FIG. 4. FIG. [Figure 10] 10 is a cross-sectional view of a portion taken along line AA in FIG. 1 according to a second embodiment. [Figure 11] 11 is an enlarged schematic cross-sectional view of an area XI surrounded by a dotted line in FIG. 10. FIG. [Figure 12] FIG. 10 is a schematic perspective view of a circular ring-shaped nozzle member according to a second embodiment. [Figure 13] 13 is an enlarged perspective schematic view of a first example of an area C surrounded by a dotted line in FIG. 12. FIG. [Figure 14] 14 is a perspective schematic diagram showing an area on the arrow side of line segment XIV-XIV in FIG. 13, further enlarged than FIG. 13. FIG. [Figure 15] 13 is an enlarged perspective schematic view of a second example of an area C surrounded by a dotted line in FIG. 12. FIG. [Figure 16]12 is an enlarged schematic cross-sectional view showing a state in which there is a possibility of interference between the nozzle member and the inner diameter surface of the cage, as a comparative example to FIG. 11. FIG. [Figure 17] 2 is a cross-sectional view of a mechanical device to which the bearing device shown in FIG. 1 is applied. [Figure 18] FIG. 18 is a cross-sectional schematic view of the mechanical device shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described with reference to the drawings.

[0012] (Embodiment 1) <Bearing device configuration> FIG. 1 is a schematic side view of a bearing device according to the present embodiment. FIG. 2 is a schematic cross-sectional view of a portion along line AA in FIG. 1 in embodiment 1. Referring to FIGS. 1 and 2, bearing device 10 according to the present embodiment is a rolling bearing device. Bearing device 10 includes bearing 11, which is a rolling bearing, and lubricant supply unit 20 (lubricant supply mechanism). Lubricant supply unit 20 supplies lubricant to bearing 11. A center line L0 passing through the center of bearing 11, which has an annular shape, extends in the left-right direction of FIG. 2, i.e., in the axial direction. Lubricant supply units 20 are arranged adjacent to each other in the axial direction of bearing 11, i.e., in the direction in which center line L0 extends.

[0013] The lubricant supply unit 20 is incorporated between an outer ring spacer 33 and an inner ring spacer 34 that are abutted against one axial end of the bearing 11. In this sense, the outer ring spacer 33 and the inner ring spacer 34 are not included in the lubricant supply unit 20. However, the lubricant supply unit 20 may also be considered to include the outer ring spacer 33 and the inner ring spacer 34. For example, the lubricant supply unit 20, the outer ring spacer 33, and the inner ring spacer 34 may be integrated together.

[0014] The bearing device 10, which includes the bearing 11 and the lubricant supply unit 20, is used by being installed in a mechanical device, for example, between a rotating shaft and a spindle housing. When the bearing device 10 is installed in a mechanical device, for example, another spacer may be abutted against the other end of the bearing 11. In this case, the bearing 11 can be positioned in the axial direction by the outer ring spacer 33, inner ring spacer 34, and other spacers.

[0015] The bearing 11 mainly comprises an outer ring 13, an inner ring 14, multiple rolling elements 15, a cage 16, and a sealing member. The outer ring 13 is, for example, a fixed raceway. However, the outer ring 13 may also be a rotating raceway. The inner ring 14 is, for example, a rotating raceway. However, the inner ring 14 may also be a fixed raceway. The multiple rolling elements 15 are interposed between the inner ring 14 and the outer ring 13. The multiple rolling elements 15 are arranged on an annular track with spacing between them in the circumferential direction. The circumferential direction is the direction in which the circumference of the annular shape such as the inner ring 14 extends. The cage 16 holds the multiple rolling elements 15 at regular intervals. The sealing member is located on the outer periphery of the cage 16. The bearing 11 can be, for example, an angular contact ball bearing, a deep groove ball bearing, or a cylindrical roller bearing. The bearing 11 is pre-filled with the desired grease. The sealing member is disposed at the end opposite to the side where the outer ring spacer 33 and the like are disposed.

[0016] The outer ring 13 of the bearing 11 has an outer ring rolling surface formed on its inner peripheral surface with which the rolling elements 15 come into contact. The inner ring 14 of the bearing 11 has an inner ring rolling surface formed on its outer peripheral surface with which the rolling elements 15 come into contact. The inner ring rolling surface faces the outer ring rolling surface. Therefore, the inner ring 14 is positioned radially inside the outer ring 13. The outer peripheral surface also includes an inclined portion 14a that continues to the inner ring rolling surface. The inclined portion 14a is inclined with respect to the axial direction so as to approach the outer ring 13 from the axial end of the inner ring 14 toward the inner ring rolling surface.

[0017] The cage 16 of the bearing 11 has a cage inner diameter surface 16b. The cage inner diameter surface 16b is a surface formed on the inner diameter side in the radial direction of the surface of the cage 16. The radial direction refers to a direction extending radially from the center of the annular nozzle member 37 toward the periphery to form a diameter (radius).

[0018] The cage inner diameter surface 16b extends from the end portion in the axial direction of the bearing 11 toward the center. In the cross section along the axial direction of the bearing 11 shown in FIG. 2, the shape of the cage inner diameter surface 16b may be linear. For example, in FIG. 2, the cage inner diameter surface 16b is linear extending along the axial direction. As shown in the cross section of FIG. 2, the cage inner diameter surface 16b may have a linear taper at both axial ends such that the diameter increases toward the outside in the axial direction. Note that the cage inner diameter surface 16b may also be curved, concave toward the outer periphery of the bearing 11.

[0019] The spacer is made up of an outer ring spacer 33 and an inner ring spacer 34. In the axial direction, one end of the outer ring 13 contacts and is connected to the outer ring spacer 33. In the axial direction, one end of the inner ring 14 contacts and is connected to the inner ring spacer 34. Here, one end of the outer ring 13 (inner ring 14) means the end located on the left side of the bearing 11 in the axial direction. In addition, in the axial direction, a part of the outer circumference of the housing main body 21 that constitutes the lubricating oil supply unit 20 faces the outer ring 13. In this way, the lubricating oil supply unit 20 is connected to the bearing 11.

[0020] The lubricant oil supply unit 20 mainly comprises a housing, and a power generation unit 25, a power supply circuit 26, a control circuit 27, a drive circuit 28, a pump 29, and a lubricant oil tank 30, which are arranged circumferentially within the housing. The housing is annular. The housing is composed of a housing main body 21 and a lid 22. In the cross section shown in FIG. 2, the housing main body 21 is cup-shaped with an opening on the surface opposite the bearing 11. The lid 22 is detachable from the housing main body 21 and closes the opening of the housing main body 21.

[0021] The power supply circuit 26 may include a charging unit. The lubricating oil tank 30 (retention unit) stores (holds) the same type of lubricating oil as the base oil of the grease pre-sealed in the bearing 11. "Pre-sealed in the bearing 11" here means that the lubricating oil is stored (held) in the bearing 11 before being supplied from the lubricating oil tank 30. The power generation unit 25, power supply circuit 26, control circuit 27, drive circuit 28, pump 29, and lubricating oil tank 30 are arranged circumferentially inside the housing main body 21. The power generation unit 25 is connected to the power supply circuit 26. The power supply circuit 26 is connected to the control circuit 27. The control circuit 27 is connected to the drive circuit 28. The drive circuit 28 is a circuit for operating a pump 29 such as a micropump. The pump 29, which is connected to the drive circuit 28, is connected to a suction tube 31 connected to the bag of the lubricating oil tank 30 and a discharge tube 32 for supplying lubricating oil from the pump 29 to the inside of the bearing 11.

[0022] 2, a nozzle member 37 is connected to the tip of the discharge tube 32. The tip of the discharge tube 32 is the end of the discharge tube 32 opposite to the base portion connected to the pump 29. A nozzle hole 37a (hole portion) connected to the discharge tube 32 is formed inside the nozzle member 37.

[0023] The nozzle member 37 is connected to the annular housing of the lubricating oil supply unit 20. The nozzle member 37 is connected to the surface of the housing body 21 that faces the bearing 11. As a result, the nozzle member 37 may be disposed, for example, entirely inside the bearing 11, i.e., in the space sandwiched between the outer ring 13 and the inner ring 14. Within this space in the bearing 11, the entire nozzle member 37 is accommodated in a position axially adjacent to the rolling elements 15. However, the nozzle member 37 is not limited to this configuration.

[0024] Furthermore, a ring-shaped sealing groove 41 is formed in the surface of the nozzle member 37 that is connected to the housing main body 21 so as to surround the nozzle hole 37a. A sealing member 42 is disposed inside the sealing groove 41. The sealing member 42 is provided to prevent the lubricating oil supplied from the discharge tube 32 to the nozzle hole 37a from leaking out from the joint surface between the nozzle member 37 and the housing main body 21.

[0025] The power generating section 25 of the lubricating oil supply unit 20 may be, for example, one that generates electricity by the Seebeck effect. Specifically, the power generating section 25 has a first thermal conductor 23a, a second thermal conductor 23b, and a thermoelectric element 24. The first thermal conductor 23a is connected to the outer ring spacer 33. The second thermal conductor 23b is arranged closer to the inner ring spacer 34 (inward in the radial direction) than the first thermal conductor 23a. The thermoelectric element 24 is arranged to connect between the first thermal conductor 23a and the second thermal conductor 23b. The thermoelectric element 24 is fixed in close contact with the first thermal conductor 23a and the second thermal conductor 23b. The thermoelectric element 24 is an element that utilizes the Seebeck effect of a Peltier element.

[0026] During use, the temperatures of the inner ring 14 and the outer ring 13 rise due to frictional heat with the rolling elements 15. The outer ring 13 is typically incorporated into the housing of the device, dissipating heat through thermal conduction. This results in a temperature difference between the inner ring 14 and the outer ring 13. The temperature of the inner ring 14 is higher than that of the outer ring 13. The temperature of the outer ring 13 is conducted to the first thermal conductor 23a, and the temperature of the inner ring 14 is conducted to the second thermal conductor 23b. The first thermal conductor 23a and the second thermal conductor 23b are arranged to penetrate the inner and outer circumferential surfaces of the housing body 21, respectively. This results in a temperature difference between the first thermal conductor 23a and the second thermal conductor 23b. This results in a temperature difference between both end faces of the thermoelectric element 24, which is arranged between the first thermal conductor 23a and the second thermal conductor 23b. This allows the thermoelectric element 24 to generate electricity through the Seebeck effect.

[0027] The inner peripheral surface of the outer ring spacer 33 and the outer peripheral surface of the first thermal conductor 23a are in close contact with each other. On the other hand, the inner peripheral surface of the second thermal conductor 23b on the inner ring side (the surface facing the inner ring spacer 34) is not in contact with the inner ring spacer 34. A gap 36 may be formed between the housing body 21 and the inner ring spacer 34.

[0028] The electric charge generated (or generated) by the power generation unit 25 is stored in the power supply circuit 26. Specifically, the electric charge is stored in a storage unit such as a storage battery or a capacitor included in the power supply circuit 26 (also called a storage circuit). It is preferable to use an electric double layer capacitor (capacitor) as the capacitor.

[0029] Control circuit 27 is a control unit for controlling the operation of pump 29 via drive circuit 28. Control circuit 27 includes a program storage unit that stores a control program and a calculation unit (microcomputer) that is connected to the program storage unit and executes the control program. Control circuit 27 can be used to preset the start time of lubricating oil supply to bearing 11, the supply timing (interval), the operating time of pump 29 for supplying lubricating oil, the amount of lubricating oil to be supplied, and other settings. By maintaining an appropriate lubricating oil supply state in this way, the lubrication life of the bearing device can be extended.

[0030] Additionally, the control circuit 27 acquires data relating to the supply status of lubricant in the lubricant supply unit 20. The control circuit 27 is also capable of outputting the data to the outside of the control circuit 27 (for example, to an output board 56 (see FIG. 18) as a receiving unit).

[0031] Drive circuit 28 may include, for example, any sensors (bearing temperature sensor, bearing rotation sensor, lubricant remaining amount sensor, lubricant temperature sensor, etc.) Signals from these sensors may be input to a calculation unit (microcomputer) of drive circuit 28, which may automatically control pump 29 according to the temperature of bearing 11 and its rotation status to adjust the amount of lubricant supplied.

[0032] Pump 29 is controlled by control circuit 27 via drive circuit 28. Pump 29 sucks lubricating oil from lubricating oil tank 30 through suction tube 31, and supplies the sucked lubricating oil to the inside of bearing 11 via discharge tube 32 and nozzle hole 37a (nozzle member 37).

[0033] The housing cover 22 may be fixed to the housing main body 21 by screws, which are an example of fixing members. The cover 22 can be removed by removing the screws, which serve as fixing members, from the tapped holes 35 to which the screws are fixed. In this way, the lubricating oil tank 30 housed in the housing main body 21 can be refilled with lubricating oil without removing the entire lubricating oil supply unit 20 from the bearing device 10.

[0034] Next, the lubricating oil tank 30 housed in the housing main body 21 may be configured as a flexible resin bag. The lubricating oil tank 30 may be arranged in an arc shape along the annular housing main body 21.

[0035] The resin bag constituting the lubricating oil tank 30 may be formed, for example, by stacking resin sheets and heat-welding the outer periphery. The outer periphery of the lubricating oil tank 30 may be the heat-welded portion.

[0036] The bag of the lubricating oil tank 30 is provided with a suction tube 31 that connects to the pump 29. When the bag of the lubricating oil tank 30 is formed by heat welding, the suction tube 31 is sandwiched between the overlapping resin sheets that are used to form the bag, and is heat-welded. In this way, the suction tube 31 can be integrated with the bag.

[0037] Fig. 3 is an enlarged schematic cross-sectional view of region III surrounded by a dotted line in Fig. 2. That is, Fig. 3 is a schematic cross-sectional view showing the positional relationship between the nozzle member in embodiment 1, the lubricating oil supplied therefrom, and the cage that the nozzle member faces. Referring to Fig. 3 in addition to Figs. 1 and 2, nozzle member 37 supplies lubricating oil (grease base oil) from lubricating oil tank 30 to the inside of bearing 11. To this end, nozzle member 37 has nozzle hole 37a therein and also land portion 37b as its tip surface.

[0038] The nozzle hole 37a is a flow path through which the lubricating oil that flows from the lubricating oil tank 30 to the discharge tube 32 flows inside the nozzle member 37 to be supplied to the inside of the bearing 11. One nozzle hole 37a is provided in the nozzle member 37. In this embodiment, as shown in FIG. 3, the nozzle member 37 is installed so that the lubricating oil is discharged vertically upward from one nozzle hole 37a. To achieve this, the discharge tube 32 and the nozzle hole 37a are positioned vertically above the center line L0.

[0039] The land portion 37b is a surface that defines the most downstream position of the lubricating oil passing through the nozzle hole 37a in the nozzle member 37. The lubricating oil is discharged from the most downstream portion of the nozzle hole 37a formed in the land portion 37b. In other words, the nozzle hole 37a is formed to reach the land portion 37b.

[0040] The land portion 37b is a flat surface on which the lubricating oil forms oil droplets. That is, as shown in FIG. 3, after flowing through the nozzle hole 37a, the lubricating oil is discharged from the land portion 37b to the outside of the nozzle member 37. The land portion 37b is the surface at the boundary between the inside and outside of the nozzle member 37. The outside of the nozzle member 37 is the space within the bearing 11, particularly the space sandwiched between the outer ring 13 and the inner ring 14. The lubricating oil can form oil droplets 38 toward the land portion 37b and the cage inner diameter surface 16b. The oil droplets 38 are, for example, hemispherical. The land portion 37b has such conditions, such as shape, material, and position.

[0041] The land portion 37b in this embodiment is defined as follows. The land portion 37b is a plane of the nozzle member 37 facing the cage inner diameter surface 16b, where the discharge port of the nozzle hole 37a is formed. The land portion 37b is a plane where the center line L1 and the line L2 intersect in a cross section along the center line L0. The discharge port of the nozzle hole 37a is the outlet from the nozzle member 37 for the lubricating oil that has flowed through the nozzle hole 37a. In other words, the discharge port is the most downstream portion of the nozzle hole 37a in the nozzle member 37. Therefore, the land portion 37b may be considered to include the discharge port of the nozzle hole 37a. The center line L1 is a line that passes through the center of a cross section of the discharge port of the nozzle hole 37a that is perpendicular to the extension direction of the nozzle hole 37a. Therefore, if the cross section of the nozzle hole 37a is circular, the center line L1 is the center of the circle at the discharge port. The line L2 corresponds to a tangent extending along the cage inner diameter surface 16b. In FIG. 3, the line L2 is axially aligned. That is, in a cross section along the axial direction as shown in FIG. 3, the straight line L2 represents the cage inner diameter surface 16b.

[0042] It is preferable that the plane of the land portion 37b is hardly curved in the vertical direction (direction perpendicular to the main surface) that forms the unevenness, and that the cross section of the land portion 37b is straight. Note that in the cross section of the present embodiment, at least a portion of the land portion 37b extends parallel to the cage inner diameter surface 16b, for example, in the cross section shown in Figure 2.

[0043] The land portion 37b facing the cage inner diameter surface 16b is disposed so that a portion of the land portion 37b overlaps with a portion of the cage inner diameter surface 16b that expands (extends) along the axial direction when viewed from the radial direction. In Fig. 3, the entire axially extending land portion 37b may face the cage inner diameter surface 16b so as to be parallel to the cage inner diameter surface 16b. However, a portion of the land portion 37b may face, for example, tapered portions at both axial ends of the cage inner diameter surface 16b in the radial direction.

[0044] In the cross section (along the axial direction) of Figure 2, the straight line of the land portion 37b and the straight line L2 extending along the cage inner diameter surface 16b do not extend in opposite directions. For example, in the cross section of Figure 2, the land portion 37b does not extend from the upper right to the lower left, and the cage inner diameter surface 16b does not extend from the lower right to the upper left. This allows oil droplets 38 to easily form between the land portion 37b and the cage inner diameter surface 16b.

[0045] The angle at which the center line L1 of the nozzle hole 37a intersects with the cage inner diameter surface 16b on the lubricant supply unit 20 side in the axial direction (left side in Figures 2 and 3) is defined as θ1. The angle θ1 is greater than 0° and equal to or less than 90°. The angle θ1 is an acute angle formed at the intersection P between the center line L1 and the straight line L2 on the lubricant supply unit 20 side in the axial direction (left side in Figure 3) as shown in Figure 3. However, the angle θ1 is not limited to this, and may be formed on the opposite side from the lubricant supply unit 20 (right side in Figure 3).

[0046] The intersection point between the land portion 37b and the center line L1 is designated as Q. The intersection point Q is the point where the center line L1 intersects with the discharge port of the nozzle hole 37a of the land portion 37b in particular. The distance in the radial direction (the vertical direction in FIG. 3) between the intersection point Q and the above-mentioned intersection point P is designated as the interval h. In FIG. 3, the interval h is the interval between the land portion 37b and the cage inner diameter surface 16b. In the cross-sectional view of FIG. 3, the interval h between the straight line of the land portion 37b and the straight line of the cage inner diameter surface 16b is preferably 0.1 mm or more and 5 mm or less.

[0047] Fig. 4 is a schematic perspective view of a circular ring-shaped nozzle member in embodiment 1. Referring to Fig. 4, nozzle member 37 may be circular ring-shaped. In this case, nozzle member 37 is entirely contained within bearing 11 in a space sandwiched between outer ring 13 and inner ring 14 (on the lubricant oil supply unit 20 side in the axial direction).

[0048] FIG. 5 is an enlarged perspective schematic diagram of a first example of region B surrounded by a dotted line in FIG. 4. Referring to FIG. 5, nozzle member 37 may be a block-shaped member obtained by cutting off a portion of the annular member shown in FIG. 4. The block-shaped nozzle member 37 is cut off along the circumferential direction. That is, nozzle member 37 shown in FIG. 5 is cut off only partially in the circumferential direction so that the entire nozzle member remains without being cut off in the radial and axial directions. Therefore, block-shaped nozzle member 37B1 shown in FIG. 5 is cut so that end faces TR at both circumferential ends are perpendicular to the outermost radial surface.

[0049] 4 and 5, the nozzle member 37 of this embodiment is made of a resin material. It is more preferable that the nozzle member 37 is made of PTFE (polytetrafluoroethylene). In particular, it is preferable that at least the land portion 37b of the nozzle member 37 is made of a resin material (PTFE).

[0050] Figure 6 is a perspective schematic diagram further enlarging the area on the arrow side of line segment VI-VI in Figure 5 than in Figure 5. The annular nozzle member 37 in Figure 4 and the block-shaped nozzle member 37B1 in Figures 5 and 6, in which a portion of the nozzle member 37 is cut away, have the shapes shown in Figures 5 and 6. With particular reference to Figures 5 and 6, the nozzle members 37 and 37B1 have an outermost axial surface 37OS on the outside (outermost part) in the axial direction, i.e., on the side facing the lubricant oil supply unit 20. The nozzle members 37 and 37B1 have two innermost axial surfaces 37IS1 and 37IS2 on the inside (innermost part) in the axial direction, i.e., on the side opposite the lubricant oil supply unit 20 (towards the rolling elements 15).

[0051] At least a portion of the shaft outermost surface 37OS is in contact with the housing main body 21. Alternatively, a portion of the shaft outermost surface 37OS can come into contact with the housing main body 21. The shaft outermost surface 37OS has a shape that is curved like an arc when viewed in a plan view from the radial direction, for example. Therefore, the shaft outermost surface 37OS can come into contact with the outer surface of the housing main body 21 so that the contact portion of the shaft outermost surface 37OS is on a straight line extending in the radial direction. Therefore, the shaft outermost surface 37OS extends and spreads generally along the radial direction.

[0052] The innermost shaft surface 37IS1 is formed on the radially outer side (upper side in FIG. 2 ) of the surface facing the rolling elements 15 in the axial direction (facing the rolling elements 15). The innermost shaft surface 37IS2 is formed on the radially inner side (lower side in FIG. 2 ) of the surface facing the rolling elements 15. Both the innermost shaft surface 37IS1 and 37IS2 have an arc-shaped curve when viewed from a radial plane, for example. The innermost shaft surface 37IS1 may be inclined so that the axial distance from the outermost shaft surface 37OS gradually increases from the outer side to the inner side in the radial direction. However, although not shown, the axial distance from the innermost shaft surface 37IS1 to the outermost shaft surface 37OS may be substantially constant (the same) from the outer side to the inner side in the radial direction. In this case, in FIG. 2 , the innermost shaft surface 37IS1 is substantially parallel to the outermost shaft surface 37OS.

[0053] The axial distance of the innermost axial surface 37IS2 from the outermost axial surface 37OS is substantially constant (the same) from the radial outside to the radial inside. However, similar to the innermost axial surface 37IS1, the innermost axial surface 37IS2 may also be inclined so that the axial distance from the outermost axial surface 37OS gradually increases from the radial outside to the radial inside.

[0054] The radially innermost side of the innermost axial surface 37IS1 and the radially outermost side of the innermost axial surface 37IS2 have approximately the same radial coordinate. A surface facing radially outward is formed between the innermost axial surface 37IS1 and the innermost axial surface 37IS2 so as to connect them. This surface is the land portion forming surface 37bb. Of the land portion forming surface 37bb, the flat portion on which the nozzle hole 37a is formed is the land portion 37b. It is preferable that the land portion 37b protrudes upward from the land portion forming surface 37bb. If the land portion 37b protrudes upward, a radial step may be formed between the land portion 37b and the land portion forming surface 37bb, and the land portion 37b may be independent from the land portion forming surface 37bb.

[0055] In the first example shown in FIGS. 5 and 6, the planar shape of land portion 37b is rectangular. However, referring to FIG. 7, the planar shape of land portion 37b may be circular. Alternatively, referring to FIG. 8, the planar shape of land portion 37b may be triangular. Furthermore, referring to FIG. 9, the planar shape of land portion 37b may be polygonal having four or more vertices. Specifically, land portion 37b may be hexagonal as shown in FIG. 9. Alternatively, the planar shape of land portion 37b may be pentagonal or rhombic. In either case, in FIG. 9, the planar shape of land portion 37b is a polygon with four or more vertices and all interior angles less than 180°. FIG. 7 is an enlarged perspective schematic diagram of a second example of region B surrounded by a dotted line in FIG. 4. FIG. 8 is an enlarged perspective schematic diagram of a third example of region B surrounded by a dotted line in FIG. 4. FIG. 9 is an enlarged perspective schematic diagram of a fourth example of region B surrounded by a dotted line in FIG. 4. 7, 8 and 9 are similar to the first example in FIG. 5 except for the planar shape of the land portion 37b, and therefore the description thereof will not be repeated here.

[0056] If the radially innermost axial surface 37IS1 and the radially outermost axial surface 37IS2 have the same radial coordinate, the land portion 37b in FIG. 2 is parallel to the center line L0. In particular, when the cage inner diameter surface 16b extends along the axial direction, the land portion 37b is preferably substantially parallel to (along) the center line L0. However, when the cage inner diameter surface 16b is inclined with respect to the axial direction, the cage inner diameter surface 16b may have an inclination angle with respect to the center line L0. This allows the center line L1 (see FIG. 3) of the nozzle hole 37a at the land portion 37b to intersect with the cross section (tangent) of the cage inner diameter surface 16b. Alternatively, this allows the land portion 37b to face the cage inner diameter surface 16b in a parallel relationship. The land portion forming surface 37bb is curved in an arc shape when viewed from the radially outer side. This is because the block-shaped nozzle member 37B1 is part of the annular nozzle member 37. The land portion forming surface 37bb of the nozzle member 37 is annular.

[0057] As shown on land portion 37b in Fig. 5 and cross section CR in Fig. 6, nozzle hole 37a enters the nozzle member from outermost shaft surface 37OS and bends at an angle close to a right angle within the nozzle member. From the bent portion, nozzle hole 37a extends to reach land portion 37b.

[0058] The nozzle member 37, 37B1 has a radially outermost surface 37OF on the radially outer side (outermost portion). The nozzle member 37, 37B1 has a radially innermost surface 37IF on the radially inner side (innermost portion), i.e., on the opposite side from the radially outermost surface 37OF. The radially outermost surface 37OF extends in the axial direction to connect the axially outermost surface 37OS to the axially innermost surface 37IS1. The radially innermost surface 37IF extends in the axial direction to connect the axially outermost surface 37OS to the axially innermost surface 37IS2. The radially outermost surface 37OF and the radially innermost surface 37IF may be curved in an arc shape when viewed in a radial plan view. The radially innermost surface 37IF overlaps both the radially outermost surface 37OF and the land portion forming surface 37bb when viewed in a radial plan view. Therefore, the area of ​​the radially innermost surface 37IF is approximately equal to the sum of the areas of the radially outermost surface 37OF and the land portion forming surface 37bb. In other words, the area of ​​the radially innermost surface 37IF is larger than that of the radially outermost surface 37OF.

[0059] <Bearing device operation> In the bearing device 10 including the bearing 11 and the lubricating oil supply unit 20, the operation of the pump 29 is controlled by the control circuit 27. This allows lubricating oil to be supplied from the lubricating oil tank 30 to the bearing 11.

[0060] The lubricating oil supplied to the inside of bearing 11 through nozzle holes 37a is temporarily stored in the area between cage inner diameter surface 16b and land portion 37b. Then, due to centrifugal force caused by rotation of inner ring 14 and capillary action, the lubricating oil flows from this area toward rolling elements 15. In this way, the lubricating oil supplied to the inside of bearing 11 is supplied to the contact areas between rolling elements 15 and inner ring 14 and outer ring 13. As a result, the lubricating performance of bearing 11 can be maintained for a long period of time.

[0061] Pump 29 is driven when the power generated by power generation unit 25 is stored in a power storage unit (e.g., a capacitor) in power supply circuit 26 and the voltage of the power storage unit reaches a certain voltage. In other words, pump 29 is driven by the power stored in power supply circuit 26 being supplied to control circuit 27. This is because power supply circuit 26, control circuit 27, drive circuit 28, and pump 29 are all connected in series.

[0062] <Action and effect> Next, the effects of the present embodiment will be described, while referring to the background art, etc. Note that the description in this section may partially overlap with the description in the section on the configuration of the bearing device described above.

[0063] The bearing device of this embodiment includes a bearing 11 and a lubricant supply unit 20 that supplies lubricant to the bearing 11. The bearing 11 includes a plurality of rolling elements 15 and a cage 16. The plurality of rolling elements 15 are arranged in a circular track. The cage 16 holds the plurality of rolling elements 15. The cage 16 has a cage inner diameter surface 16b formed on the inner diameter side in the radial direction. The lubricant supply unit 20 includes a holding portion (lubricant tank 30) and nozzle members 37, 37B1. The lubricant tank 30 holds lubricant to be supplied to the interior of the bearing 11. The nozzle members 37, 37B1 supply lubricant from the lubricant tank 30 to the interior of the bearing 11. The nozzle members 37, 37B1 have a tip surface (land portion 37b). The land portion 37b is a flat surface that allows the lubricant to form oil droplets 38 toward the cage inner diameter surface 16b.

[0064] When the lubricating oil supply unit 20 is activated, the lubricating oil passes through the inside of the nozzle member and forms oil droplets 38 at the discharge port. The expanded oil droplets 38 come into contact with the cage inner diameter surface 16b. In other words, the lubricating oil discharged from the nozzle member becomes the oil droplets 38 shown in Figure 3 on the cage inner diameter surface 16b. In this way, the oil droplets 38 spread over the surface of the cage 16 due to capillary action. Then, as the rotating ring (e.g., inner ring 14) of the bearing 11 rotates, the lubricating oil reaches the rolling elements 15 from the pocket surfaces of the cage 16. The lubricating oil then reaches the raceway surfaces of the outer ring 13 and inner ring 14 from the rolling elements 15.

[0065] Oil is supplied from the lubricating oil tank 30 so that oil droplets 38 are formed between the land portion 37b and the cage inner diameter surface 16b. By supplying an optimal amount of oil droplets 38, which is smaller than the large amount of air oil that is discharged, lubricating oil is smoothly supplied throughout the entire interior of the bearing 11. This improves the lubrication durability of the bearing 11. In other words, according to this embodiment, the oil droplets 38 can efficiently replenish oil that is lacking in the rolling contact portion. This allows the capacity of the lubricating oil tank 30 of the lubricating oil supply unit 20 to be made compact. Furthermore, in this embodiment, the lubricating durability of the bearing 11 can be improved by supplying a small amount of lubricating oil with high efficiency.

[0066] When the bearing device 10 rotates at high speeds, heat generated by the bearing 11 accelerates the deterioration of the lubricating oil. This can cause a problem in that the lubrication durability of the bearing 11 cannot be ensured even at rotational speeds lower than the maximum rotational speed at which the bearing 11 can be used. On the other hand, the market is demanding even higher rotational speeds, that is, increased lubrication durability of the bearing 11 under high-speed rotation. According to this embodiment, the lubrication durability of the bearing 11 can be increased even at high-speed rotation.

[0067] Compressed air is used to supply air-oil to the desired area. In other words, the lubricating oil is sent using the pressure of the compressed air. However, there are situations where using air-oil is not desirable, such as when miniaturizing the equipment. In such situations, compressed air is not used, but instead oil droplets 38 are formed as in this embodiment, and the surface tension of the oil droplets 38 is used to partially adhere to the mating surface, i.e., the cage inner diameter surface 16b. This draws the lubricating oil toward the cage 16. This eliminates the need for a large housing and tank for air-oil, and eliminates the need to enlarge the equipment. As described above, this embodiment allows for smooth supply of lubricating oil to the rolling contact parts without enlarging the equipment.

[0068] In the bearing device 10, the nozzle members 37, 37B1 may be formed from a resin material. Resin materials have excellent oil repellency. Therefore, if the nozzle member 37 is made of a resin material, the lubricating oil discharged from the nozzle holes 37a at the land portions 37b can be formed into droplets as shown in FIG. 3. In particular, if the nozzle member 37 is made of PTFE, its high oil repellency can more reliably form the lubricating oil into droplets.

[0069] The oil droplets 38 supplied from the nozzle member 37 to the cage inner diameter surface 16b are required to be deposited on the cage inner diameter surface 16b due to surface tension. To facilitate deposition of the lubricating oil on the cage inner diameter surface 16b, a shorter distance h between the land portion 37b and the cage inner diameter surface 16b (see FIG. 3) is preferable. However, shortening the distance h may result in interference (crash) between the land portion 37b and the cage inner diameter surface 16b. On the other hand, increasing the distance h creates a trade-off problem: it becomes more difficult for the lubricating oil (oil droplets 38) to reach the cage 16b from the nozzle member 37. Therefore, by improving the oil repellency of the nozzle member 37 as described above, the high surface tension of the oil droplets 38 makes it easier for the oil droplets 38 to deposit on the cage inner diameter surface 16b, even if the distance h is long. From this perspective, the distance h is preferably set to a value between 0.1 mm and 5 mm.

[0070] Furthermore, the nozzle member 37 is made of a resin material, which makes it easier to form the nozzle holes 37a than when the nozzle member 37 is made of a metal that is harder than a resin material.

[0071] In the bearing device 10, the nozzle member may be either annular (nozzle member 37) or block-shaped (nozzle member 37B1) with a circumferentially cut-away portion of the annular shape. In other words, the nozzle member 37 is annular rather than elongated. This allows for control of the swirling flow and the flow of adhering grease around the discharge port of the nozzle hole 37a. Controlling these flows prevents the formation of oil droplets 38 at the discharge port from being impeded.

[0072] If the nozzle member 37B1 is block-shaped, it has the same effects as the annular nozzle member 37, and also has the following effect. Referring to Fig. 5, the nozzle member 37B1, in which only a portion of the circumferential area of ​​the nozzle member 37 is cut away, allows the lubricating oil 38A to easily flow from the inside to the outside of the nozzle member 37B1, as shown by the arrows in the figure. This makes it possible to prevent the lubricating oil from unintentionally accumulating inside the inner ring 14 (around the rotating shaft).

[0073] It is preferable that the nozzle member body is not located in any other area except for land portion 37b, which contributes to the discharge of lubricating oil. The nozzle member body located in another area would obstruct the flow of lubricating oil 38A shown in FIG. 5. There is also the possibility that the body may unintentionally interfere with other components. Therefore, nozzle member 37B1 is made block-shaped, with its volume smaller than that of nozzle member 37. This reduces the possibility of nozzle member 37B1 unintentionally interfering with other components.

[0074] In the bearing device 10, the nozzle member 37, 37B1 is formed with a hole (nozzle hole 37a) that reaches the tip end surface (land portion 37b). The nozzle hole 37a circulates and discharges lubricating oil to be supplied to the inside of the bearing 11. In a cross section along the axial direction, the center line L1 of the nozzle hole 37a intersects with the cage inner diameter surface 16b (straight line L2). The angle θ1 at which the center line L1 of the nozzle hole 37a on the lubricating oil supply unit 20 side in the axial direction intersects with the cage inner diameter surface 16b (straight line L2) is greater than 0° and equal to or less than 90°.

[0075] The shorter the path from the lubricating oil supply unit 20 to the discharge port of the nozzle member, the smaller the pressure loss in the nozzle hole 37a. Therefore, the shorter the path, the smoother the lubricating oil is delivered to the discharge port. From this perspective, it is preferable that the angle θ1 formed by the intersection of the center line L1 and the straight line L2 in Figure 3 is greater than 0° and less than 90°.

[0076] In the bearing device 10, the planar shape of the land portion 37b is either circular or triangular. In the bearing device 10, the planar shape of the land portion 37b is polygonal with four or more vertices. In this way, the nozzle member 37 has the land portion 37b that extends as a flat surface. Therefore, the oil droplets 38 discharged from the land portion 37b have a height h sufficient to easily reach the cage inner diameter surface 16b.

[0077] The land portion 37b protrudes upward (radially outward) from the land portion forming surface 37bb. This prevents the flat surface of the land portion 37b from being significantly larger than the size of the oil droplet 38. In other words, the land portion 37b has a boundary with the land portion forming surface 37bb at a position slightly away from the outer edge of the nozzle hole 37a. If the land portion 37b were significantly larger than the nozzle hole 37a, the oil droplet 38 would not rise in the direction of height h and would instead wet and spread along the large flat surface of the land portion 37b. This prevents the oil droplet 38 from smoothly reaching the cage 16. However, in this embodiment, the land portion 37b has a relatively small flat surface. This allows the oil droplet 38 to smoothly reach the cage 16 from the land portion 37b.

[0078] In the above-described bearing device 10, the bearing 11 is pre-filled with lubricating oil. The lubricating oil is grease. This allows for applications where air-oil lubrication is undesirable. For example, grease lubrication is increasingly being used instead of air-oil lubrication for machine tool spindle bearings. This is intended to reduce environmental impact and costs. Grease lubrication eliminates the need for the lubricating oil tank and lubricating oil supply system used in air-oil lubrication. The lubricating oil tank used in air-oil lubrication is large, and the lubricating oil supply system is a complex one with a pump that has a forced discharge function. Therefore, grease lubrication allows for a more compact facility compared to air-oil lubrication. Furthermore, grease lubrication uses less lubricating oil than air-oil lubrication. Therefore, grease lubrication is environmentally friendly and reduces initial and running costs.

[0079] In the case of a grease-lubricated bearing, application of this embodiment facilitates the separation of grease adhering to the cage bore surface 16b. In other words, capillary action actively acts on the liquid lubricating oil adhering to the cage bore surface 16b. This allows the liquid lubricating oil to sufficiently reach the rolling surfaces inside the bearing 11 when the grease is depleted, i.e., when there is little grease.

[0080] (Embodiment 2) In the second embodiment, the same configurations, features, materials, etc. as those in the first embodiment will not be described repeatedly unless it is preferable to do so again.

[0081] <Bearing device configuration> FIG. 10 is a cross-sectional view of a portion of the second embodiment taken along line AA in FIG. 1. FIG. 11 is an enlarged cross-sectional view of region XI enclosed by a dotted line in FIG. 10. Referring to FIGS. 1, 10, and 11, in this embodiment, the lubricating oil is installed so that it is discharged vertically downward from one nozzle hole 37a. To achieve this, the discharge tube 32 and the nozzle hole 37a are disposed vertically below the center line L0. Note that the first embodiment may also be installed in the same manner as this embodiment (with the nozzle hole 37a disposed vertically below the center line L0).

[0082] In this embodiment, the land portion 37b in FIG. 11 is the right-hand surface of the nozzle member 37 in FIG. 10, where the discharge port of the nozzle hole 37a is formed. In FIG. 11, as in FIGS. 2 and 3, the angle θ1 between the center line L1 and the straight line L2 is greater than 0° and less than 90°. As an example, the angle θ1 in FIG. 11 is approximately 30°. Furthermore, the following holds true in FIG. 11: θ2 is the angle formed by the land portion 37b of the nozzle member 37 and a side surface 37c of the surface of the nozzle member 37 adjacent to the lubricating oil supply unit 20 side of the land portion 37b in a cross section along the axial direction. In this case, the angle θ2 is greater than 0° and less than (θ1 + 90)°. Furthermore, it is preferable that the side surface 37c has an inclination angle greater than 0° with respect to the straight line L2 (i.e., it is not parallel to the straight line L2).

[0083] 11, the side surface 37c faces the cage inner diameter surface 16b (facing vertically downward). However, the discharge port of the nozzle hole 37a is not formed on the side surface 37c. Therefore, the side surface 37c is not a land portion.

[0084] 11, the intersection of the center line L1 and the straight line L2 is designated as P. Also in FIG. 11, the intersection of the land portion 37b (the outlet of the nozzle hole 37a) and the center line L1 is designated as Q. In this case, the interval h, which is the distance between the intersection points P and Q in the radial direction (the vertical direction in FIG. 11), is preferably 0.1 mm or more and 5 mm or less.

[0085] Fig. 12 is a schematic perspective view of a circular ring-shaped nozzle member in embodiment 2. Referring to Fig. 12, in embodiment 2, nozzle member 37 may also be circular ring-shaped, as in embodiment 1. Fig. 13 is an enlarged schematic perspective view of area C surrounded by a dotted line in Fig. 12. Referring to Fig. 13, nozzle member 37B2 may be a block-shaped nozzle member obtained by cutting out a portion of the circular ring-shaped nozzle member in Fig. 12.

[0086] Figure 14 is a perspective schematic diagram further enlarging the area on the arrow side of line segment XIV-XIV in Figure 13 than in Figure 13. The annular nozzle member 37 in Figure 12 and the block-shaped nozzle member 37B2 in Figure 13 and Figure 14, in which a portion of the nozzle member 37 is cut away, all have the shapes shown in Figures 13 and 14. With particular reference to Figures 13 and 14, the nozzle members 37 and 37B2 have an outermost axial surface 37OS on the outside (outermost part) in the axial direction, i.e., on the side facing the lubricant oil supply unit 20. The nozzle members 37 and 37B2 have an innermost axial surface 37IS on the inside (innermost part) in the axial direction, i.e., on the opposite side to the lubricant oil supply unit 20 in the axial direction (towards the rolling elements 15).

[0087] At least a portion of outermost shaft surface 37OS in the present embodiment is in contact with housing body 21 in a manner similar to that of outermost shaft surface 37OS in embodiment 1. Since the manner of contact is the same as that in embodiment 1, the description thereof will not be repeated.

[0088] The innermost shaft surface 37IS is formed on the surface facing the rolling elements 15 in the axial direction (facing the rolling elements 15) radially outward (lower in FIG. 14 ) of a radially innermost surface 37IF (described later). The innermost shaft surface 37IS is formed on the surface facing the rolling elements 15 radially outward (lower in FIG. 14 ) of a land portion forming surface 37bb. The innermost shaft surface 37IS has a curved arc shape when viewed from a radial plane, for example. The innermost shaft surface 37IS may be inclined so that the axial distance from the outermost shaft surface 37OS gradually increases from the outer side to the inner side in the radial direction. However, although not shown, the axial distance from the innermost shaft surface 37IS to the outermost shaft surface 37OS may be substantially constant from the outer side to the inner side in the radial direction. In this case, in FIG. 14 , the innermost shaft surface 37IS is substantially parallel to the outermost shaft surface 37OS.

[0089] In the cross section CR of FIG. 14, a thin groove-like surface 37d and a side surface 37c are continuous from the radially innermost portion (the top in FIG. 14) of the innermost shaft surface 37IS. On the opposite side of each of these surfaces from the innermost shaft surface 37IS, a surface is formed that faces radially outward while being slightly inclined toward the axially inner side (the rolling element 15 side). This surface is the land portion-forming surface 37bb. The land portion-forming surface 37bb is continuous and adjacent to the side surface 37c. Alternatively, the thin groove-like surface 37d may be absent, and the side surface 37c may be continuous directly from the radially innermost portion of the innermost shaft surface 37IS, and the side surface 37c may be continuous directly from the land portion-forming surface 37bb. The inclination angles of the surface 37d and the side surface 37c relative to the axial direction in the cross section CR may be arbitrary as long as the land portion 37b satisfies the requirements for a land portion. The surface 37d and the side surface 37c are bent toward each other in the cross section CR as shown in FIG. 14. In this embodiment, as long as the center line L1 and the straight line L2 of the cage inner diameter surface 16b intersect, the land portion 37b does not have to be parallel to the cage inner diameter surface 16b. Normally, the land portion 37b is inclined with respect to the cage inner diameter surface 16b. As shown in FIG. 11, the land portion 37b may be positioned vertically above the cage inner diameter surface 16b.

[0090] As shown on land portion 37b in Fig. 13 and cross section CR in Fig. 14, nozzle hole 37a enters the nozzle member from outermost shaft surface 37OS and bends at an angle close to a right angle within the nozzle member. From the bent portion, nozzle hole 37a extends to reach land portion 37b.

[0091] The nozzle member 37, 37B2 has a radially outermost surface 37OF on the radially outer side (outermost portion). The nozzle member 37, 37B2 has a radially innermost surface 37IF on the radially inner side (innermost portion), i.e., on the radially opposite side from the radially outermost surface 37OF. The radially outermost surface 37OF extends in the axial direction to connect the axially outermost surface 37OS to the axially innermost surface 37IS. The radially innermost surface 37IF extends in the axial direction to connect the axially outermost surface 37OS to the land portion forming surface 37bb. The radially outermost surface 37OF and the radially innermost surface 37IF may be curved in an arc shape when viewed in a radial plan view. The radially innermost surface 37IF overlaps both the radially outermost surface 37OF and the land portion forming surface 37bb when viewed in a radial plan view. Furthermore, the radially innermost surface 37IF also overlaps the side surface 37c when viewed in a radial plan view. The radially innermost surface 37IF has an area larger than that of the radially outermost surface 37OF and the land portion forming surface 37bb.

[0092] As shown in Figures 13 and 14, the planar shape of land portion 37b may be circular. Alternatively, referring to Figure 15, the planar shape of land portion 37b may be triangular. Alternatively, in this embodiment, as in Figure 9, the planar shape of land portion 37b may be a polygon with four or more vertices, such as a hexagon. Figure 15 is an enlarged perspective schematic diagram of a second example of region C surrounded by a dotted line in Figure 12. Figure 15 is similar to the first example in Figure 13 except for the planar shape of land portion 37b, and therefore description thereof will not be repeated here.

[0093] The shapes of the nozzle members 37, 37B1, and 37B2 in each embodiment may be changed as appropriate depending on the operating conditions. Specifically, the shapes of the nozzle members 37, 37B1, and 37B2 may be changed as appropriate depending on the rotational speed of the bearing device 10, the temperature during operation, and the vibration during operation.

[0094] <Action and effect> The bearing device 10 of this embodiment has, for example, the configuration shown in Figures 10 and 11. That is, the angle θ2 formed by the tip surface (land portion 37b) of the nozzle member 37, 37B2 and the side surface 37c of the surface of the nozzle member 37, 37B2 adjacent to the lubricating oil supply unit 20 side of the land portion 37b in the axial cross section is greater than 0° and equal to or less than (θ1 + 90)°.

[0095] For example, as shown in Figures 10 and 11, the nozzle member 37 is positioned vertically below the center line L0, and lubricating oil is discharged vertically downward from the nozzle hole 37a. Therefore, oil droplets 38 formed at the discharge port naturally fall due to gravity. Therefore, compared to when lubricating oil is discharged vertically downward from the nozzle hole 37a as shown in Figure 3, it is easier to supply lubricating oil to the cage inner diameter surface 16b. If the angle θ2 satisfies the above requirements, the oil droplets 38 are more likely to leave the land portion 37b. If the above requirements are satisfied, the angle between the side surface 37c and the cage inner diameter surface 16b increases the gap between them. Furthermore, the inclination due to the angle between the side surface 37c and the cage inner diameter surface 16b makes it easier for the oil droplets 38 to move downward (toward the cage inner diameter surface 16b). Therefore, according to this embodiment, the effects of embodiment 1 are further enhanced.

[0096] However, it is difficult to satisfy the above-mentioned condition for angle θ2 for a nozzle member 37 of any shape. FIG. 16 is an enlarged schematic cross-sectional view showing a situation in which the nozzle member and the cage inner diameter surface may interfere with each other, as a comparative example to FIG. 11. Referring to FIG. 16, this example satisfies the above-mentioned condition for angle θ2, but there is a possibility that the nozzle member 37 may interfere with (collide with) the cage inner diameter surface 16b at the lower right of the figure. Therefore, from the perspective of avoiding such problems, it is preferable to use nozzle members 37, 37B2 having the shape characteristics shown in FIGS. 13 and 14, for example.

[0097] (Embodiment 3) <Machinery Configuration> The configuration of a spindle for a machine tool, which is an example of a mechanical device to which the bearing device according to the first and second embodiments is applied, will be described with reference to FIGS.

[0098] FIG. 17 is a cross-sectional view of a machine device to which the bearing device shown in FIG. 1 is applied. FIG. 18 is a cross-sectional view of the machine device shown in FIG. 17. FIG. 17 includes a cross-sectional view of a portion taken along line XVII-XVII in FIG. 18. Referring to FIGS. 17 and 18, a machine tool spindle 50 serving as a machine device according to this embodiment mainly includes a rotating shaft 51, a spindle housing 52, an outer peripheral housing 53, and a bearing device 10 (see FIG. 1). The spindle housing 52 (housing) is disposed on the outer peripheral side of the rotating shaft 51 so as to surround the periphery of the rotating shaft 51. The outer peripheral housing 53 is disposed on the outer periphery of the spindle housing 52. The bearing device 10 supports the rotating shaft 51 rotatably relative to the spindle housing 52.

[0099] Two bearing devices are arranged on the outer periphery of the rotating shaft 51. The inner ring 14 and inner ring spacer 34 of the bearing in the bearing device are fitted and fixed to the side surface of the rotating shaft 51. The outer ring 13 and outer ring spacer 33 of the bearing are fitted and fixed to the inner circumferential surface of the spindle housing 52. The bearing including the inner ring 14, outer ring 13, and rolling elements 15, which are balls, arranged between the inner ring 14 and outer ring 13 is an angular contact ball bearing. A lubricating oil supply unit 20 is arranged between the inner ring spacer 34 and outer ring spacer 33, which are arranged adjacent to the bearings. Another spacer is fitted and fixed to the rotating shaft 51 and spindle housing 52 between the two bearings (on the side opposite to the side where the lubricating oil supply unit is arranged), and abuts against the inner ring 14 and outer ring 13.

[0100] In an area facing the control circuit 27 of the lubricating oil supply unit, a through hole is formed through the housing main body 21 (see FIG. 2), the outer ring spacer 33, the spindle housing 52, and the outer housing 53. A flat portion is provided on the surface of the outer housing 53 at the outer peripheral end of the through hole, and a pedestal 57 is disposed on the flat portion. An output board 56 is disposed on the pedestal 57. The output board 56 and the control circuit 27 of the lubricating oil supply unit 20 are electrically connected, for example, by a contact probe 54. The contact probe 54 is disposed inside the through hole. One end of the contact probe 54 contacts an electrode pad (not shown) of the control circuit 27, and the other end of the contact probe 54 is connected to the output board 56 by a conductive wire 55. The contact probe 54 may be connected and fixed to the output board 56 side. Furthermore, the output board 56 and the control circuit 27 may be connected by wire as described above, but may also be connected using other connection means (for example, optical communication means using a light-emitting element and a light-receiving element).

[0101] A cover member 58 is fixed to the base 57 so as to cover the output board 56 arranged on the base 57. A battery, which is a power source for driving the circuit of the output board 56, and a storage unit are arranged on the output board 56. The battery may be, for example, a coin battery or a button battery. A lithium battery is preferably used as the battery. A holder for securing such a battery is arranged on the surface of the output board 56. The storage unit may be, for example, a holding unit (slot) for connecting and securing a card-type external storage medium, and the external storage medium removably secured to the holding unit. Any conventionally known storage medium, such as a memory card, may be used as the external storage medium.

[0102] Cover member 58 has a U-shaped elongated hole (a hole for arranging a fixing bolt) formed therein so that cover member 58 can be removed from base 57 simply by loosening fixing bolt 59, which is a connecting member to base 57. The battery and external storage medium can be replaced with cover member 58 removed from base 57.

[0103] The output board 56, sealed by the base 57 and cover member 58, constitutes the main part of the voltage monitoring unit. The base 57 and cover member 58 can be provided with any waterproof structure to prevent the intrusion of coolant used during processing using the processing machine spindle. Examples of waterproof structures that can be used include packing, O-rings, caulking, and resin molding.

[0104] The machine tool spindle 50 described above also includes a unit main body and a lubricant supply unit. The unit main body is connected to the bearing 11 (see FIG. 2) including the inner ring 14, outer ring 13, and rolling elements 15 as described above, and includes a control unit having a control circuit 27 (see FIG. 1). The lubricant supply unit includes an external output unit 70, which is a voltage monitoring unit connected to the control unit by a connection line (contact probe 54).

[0105] The unit main body includes a control unit, a power supply unit, a lubricant supply unit, and a lubricant storage unit (lubricant tank 30). The control unit includes a control circuit 27. The power supply unit includes a power generation unit 25 (see FIG. 1) and a power supply circuit 26 (see FIG. 1). The lubricant supply unit includes a power supply circuit 26, a drive circuit 28, and a pump 29. The control unit is connected to the power supply unit and the lubricant supply unit. The control unit controls the lubricant supply state in the lubricant supply unit and acquires data related to the lubricant supply state. Examples of such data include the timing of lubricant supply, the interval between lubricant supply, and data on the voltage (storage voltage) in the power supply circuit (specifically, the power storage unit) when pump 29 is operated.

[0106] Any configuration can be adopted for the connection between the control circuit 27 of the control unit and the output board 56 of the external output unit 70. However, for example, the calculation unit (microcomputer) installed in the control circuit 27 and the calculation unit of the output board 56 may be connected by a connection wire. The calculation unit of the control circuit 27 is connected to a power source and a ground by wiring or the like. Furthermore, in the output board 56, the calculation unit is connected to a battery and a memory unit. A signal (a signal transmitted from the control circuit 27) indicating data such as voltage can be transmitted from the calculation unit to the memory unit.

[0107] With the above configuration, data related to the lubricant supply status transmitted from the control circuit 27 is stored in the memory unit of the output board 56. The timing for transmitting the data from the control circuit 27 to the output board 56 can be any timing. However, for example, the data may be transferred from the control circuit 27 to the output board 56 when the memory unit of the control circuit 27 (such as a memory element included in the calculation unit or a memory element provided in the control circuit 27 independently of the calculation unit) is full of the data. If the data includes data on the time change in the stored voltage of the power supply unit, the data can be saved in an external storage medium via the memory unit of the output board 56 and then imported into an external computer or the like using the external storage medium. In this way, the status of the lubricant supply unit (such as the power generation status and the operating status of the pump 29) can be checked on the external computer.

[0108] <Operation of mechanical device> 17 and 18, a machine tool spindle 50, which is an example of a mechanical device, has a rotating shaft 51 connected to a predetermined drive shaft and rotatable relative to a spindle housing 52. In a bearing device that supports the rotating shaft 51, a lubricating oil supply unit periodically supplies lubricating oil to bearings 11 (see FIG. 2). This improves the reliability and durability of the machine tool spindle 50.

[0109] The timing of oil supply to the bearing 11 by the lubricating oil supply unit 20 in the bearing device 10 is arbitrary. However, when the rotating shaft 51 rotates at high speed, a swirling air flow occurs around the rolling elements 15 as the bearing 11 rotates. This can cause the lubricating oil to spread, which can hinder smooth delivery of the lubricating oil. Therefore, from the perspective of avoiding such problems, it is preferable to oil the bearing 11 while the bearing 11 is stopped or when the bearing 11 is rotating at a rotational speed with a dn value of 200,000 or less.

[0110] <Action and effect> The mechanical device (machine tool spindle 50) according to the first and second embodiments includes a rotating shaft 51, a housing (spindle housing 52) disposed on the outer periphery of the rotating shaft 51, and the bearing device 10 that rotatably supports the rotating shaft 51 relative to the housing. This allows the bearing device 10 to operate stably for a long period of time, which in turn allows the mechanical device to operate stably for a long period of time.

[0111] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Unless there is a contradiction, at least two of the embodiments disclosed herein may be combined. The basic scope of the present disclosure is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0112] Various aspects of the present disclosure are summarized below as appendices.

[0113] (Appendix 1) A bearing, a lubricating oil supply unit for supplying lubricating oil to the bearing, The bearing is a plurality of rolling elements arranged side by side on a circular track; a cage that holds the plurality of rolling elements, the cage has a cage inner diameter surface formed on an inner diameter side in the radial direction, The lubricating oil supply unit includes: a retaining portion for retaining lubricating oil to be supplied to the inside of the bearing; a nozzle member for supplying the lubricating oil from the holding portion to the inside of the bearing, the nozzle member has a tip surface, The tip end surface is a flat surface for forming oil droplets of the lubricating oil toward the inner diameter surface of the retainer.

[0114] (Appendix 2) 2. The bearing device according to claim 1, wherein the nozzle member is made of a resin material.

[0115] (Appendix 3) 3. The bearing device according to claim 1, wherein the nozzle member is either an annular shape or a block shape with a circumferential portion of the annular shape cut away.

[0116] (Appendix 4) The nozzle member has a hole formed therein that reaches the tip end surface, the hole portion allows the lubricating oil to be supplied to the inside of the bearing to circulate and be discharged; In a cross section along the axial direction, a center line of the hole intersects with an inner diameter surface of the cage, 4. The bearing device according to any one of claims 1 to 3, wherein an angle θ1 formed between the center line of the hole on the lubricant oil supply unit side in the axial direction and the inner diameter surface of the retainer is greater than 0° and not greater than 90°.

[0117] (Appendix 5) The bearing device described in Appendix 4, wherein the angle θ2 formed by the tip surface of the nozzle member and the side of the surface of the nozzle member adjacent to the tip surface on the lubricating oil supply unit side in a cross section along the axial direction is greater than 0° and less than or equal to (θ1 + 90)°.

[0118] (Appendix 6) 6. The bearing device according to any one of claims 1 to 5, wherein the planar shape of the tip end surface is either circular or triangular.

[0119] (Appendix 7) 6. The bearing device according to any one of claims 1 to 5, wherein the planar shape of the tip end surface is a polygon having four or more vertices.

[0120] (Appendix 8) The lubricating oil is sealed in the bearing in advance, 8. The bearing device according to any one of claims 1 to 7, wherein the enclosed lubricating oil is grease.

[0121] (Appendix 9) A rotation axis; a housing disposed on an outer circumferential side of the rotary shaft; A mechanical device comprising: the bearing device according to any one of appendices 1 to 8, which rotatably supports the rotating shaft relative to the housing. [Explanation of symbols]

[0122] 10 bearing device, 11 bearing, 13 outer ring, 14 inner ring, 14a inclined portion, 15 rolling element, 16 cage, 16b cage inner diameter surface, 20 lubricating oil supply unit, 21 housing body, 22 cover body, 23a first heat conductor, 23b second heat conductor, 24 thermoelectric element, 25 power generation unit, 26 power supply circuit, 27 control circuit, 28 drive circuit, 29 pump, 30 lubricating oil tank, 31 suction tube, 32 discharge tube, 33 outer ring spacer, 34 inner ring spacer, 36 gap, 37, 37B1, 37B2 nozzle member, 37a nozzle hole, 37b land portion, 37bb land portion forming surface, 37c side surface, 37d surface, 37IF innermost diameter surface, 37IS, 37IS1, 37IS2 Innermost surface of shaft, 37OF outermost surface of diameter, 37OS outermost surface of shaft, 38 oil droplet, 38A lubricating oil, 41 seal groove, 42 seal material, 50 machine tool spindle, 51 rotating shaft, 52 spindle housing, 53 outer peripheral housing, 54 contact probe, 55 conductive wire, 56 output board, 57 base, 58 cover material, 59 fixing bolt, 70 external output part, CR cross section, L0, L1 center lines, L2 straight line, TR end face.

Claims

1. A bearing, a lubricating oil supply unit for supplying lubricating oil to the bearing, The bearing is a plurality of rolling elements arranged side by side on a circular track; a cage that holds the plurality of rolling elements, the cage has a cage inner diameter surface formed on an inner diameter side in the radial direction, The lubricating oil supply unit includes: a retaining portion for retaining lubricating oil to be supplied to the inside of the bearing; a nozzle member for supplying the lubricating oil from the holding portion to the inside of the bearing, the nozzle member has a tip surface, The tip end surface is a flat surface for forming oil droplets of the lubricating oil toward the inner diameter surface of the retainer.

2. 2. The bearing device according to claim 1, wherein the nozzle member is made of a resin material.

3. 3. The bearing device according to claim 1, wherein the nozzle member is either annular or block-shaped with a circumferentially cut-away portion of the annular shape.

4. The nozzle member has a hole formed therein that reaches the tip end surface, the hole portion allows the lubricating oil to be supplied to the inside of the bearing to circulate and be discharged; In a cross section along the axial direction, a center line of the hole intersects with an inner diameter surface of the cage, 3. The bearing device according to claim 1, wherein an angle θ1 between a center line of the hole on the lubricating oil supply unit side in the axial direction and an inner diameter surface of the cage is greater than 0° and not greater than 90°.

5. 5. The bearing device of claim 4, wherein the angle θ2 formed by the tip surface of the nozzle member and the side of the surface of the nozzle member adjacent to the tip surface on the lubricating oil supply unit side in a cross section along the axial direction is greater than 0° and is not greater than (θ1 + 90)°.

6. 3. The bearing device according to claim 1, wherein the planar shape of the tip end surface is either circular or triangular.

7. 3. The bearing device according to claim 1, wherein the planar shape of the tip end surface is a polygon having four or more vertices.

8. The lubricating oil is sealed in the bearing in advance, 3. The bearing device according to claim 1, wherein the enclosed lubricating oil is grease.

9. A rotation axis; a housing disposed on an outer circumferential side of the rotary shaft; A mechanical device comprising: the bearing device according to claim 1 or 2, which rotatably supports the rotating shaft relative to the housing.

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