Bearing device and rotating shaft device

Abstract

The front-side bearing device is provided with: a rolling bearing (20) that rotatably supports a rotating shaft (60) with respect to a housing (50); and an outer ring spacer (40) and an outer ring pressing member that are embedded in the housing (50) and position the outer ring (22) of the rolling bearing (20) in the axial direction. The front bearing device supplies a lubricant (G) to the inside of the rolling bearing (20) via the lubricant supply path (52). One side surface (22b) of the outer ring (22) is offset toward the axial center side from a side surface (21b) of the inner ring (21) of the rolling bearing (20), and an opening (41) through which the outer ring spacer (40) passes in the radial direction is formed in an end surface (43) of the outer ring spacer (40) in contact with the offset side surface (22b).

Description

Technical Field

[0001] The present invention relates to bearing assemblies and shaft assemblies using the bearing assemblies, and more specifically, to improvements in bearing assemblies and shaft assemblies that enable efficient discharge of lubricant supplied to the bearing. Background Technology

[0002] Traditionally, bearing systems supporting machine tool spindles, such as spindles, used methods like jet lubrication, oil mist lubrication, oil-air lubrication, and grease lubrication. In recent years, with the increasing speed of spindles, lubrication methods have been developed that involve intermittently applying minute amounts of lubricating oil to the raceway and rolling surfaces of rolling bearings at high speeds, providing thin lubrication to the rolling surfaces, and intermittently replenishing grease into the bearing space. This has improved the lubrication capabilities for applications exceeding dmN1 million (dm: pitch circle diameter of the rolling bearing (mm), N: rotational speed (min)). -1 The high-speed performance of the bearing is achieved by properly discharging the supplied lubricant, such as oil or grease, in the lubrication system that supplies or replenishes the bearing. This is an important factor in minimizing the stirring resistance of the lubricant generated during the rotation of the shaft, thereby preventing the bearing temperature from rising and the torque from increasing.

[0003] Typically, the grease inside a spindle accounts for 10% to 30% of the bearing's volume. If the base oil in the grease, responsible for lubricating the rotating bearing, is consumed, poor lubrication occurs, leading to bearing seizure. Therefore, the lifespan of the grease, i.e., the time it takes for the base oil to be consumed, is the lifespan of a grease-sealed spindle. To extend grease life, methods include increasing the amount of grease sealed inside the bearing or adding grease to the spacers adjacent to the bearing. However, excessive grease sealing results in a lengthy break-in period. Furthermore, if a large amount of grease located in the outer ring of the bearing and in the spacers enters the bearing's rolling surfaces, a rapid temperature rise occurs, posing a risk of seizure. In grease-replenishing types, intermittently supplying fresh grease to the bearing extends life compared to grease sealing. However, if the grease is not properly drained from the bearing, the risk of seizure due to a rapid temperature rise is very high.

[0004] Patent Document 1 describes a spindle assembly (bearing assembly) comprising: multiple first radial oil passages formed on an outer ring positioning member; a circumferential aligning groove communicating with the multiple first radial oil passages; and a second radial oil passage formed on the housing by connecting an oil drain hole of the housing to the circumferential aligning groove. Thus, regardless of the rotational orientation, lubricating oil can be discharged from the oil drain hole, preventing abnormal overheating caused by excessive lubricant inside the bearing.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-2622 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] However, conventional bearing assemblies are configured such that further supplying lubricant into the bearing space, which is already filled with lubricant through continuous supply, causes the lubricant to be squeezed out of the bearing. Therefore, the force required to expel the lubricant from the bearing is relatively small. Consequently, the storage space formed in the outer ring spacer cannot be adequately filled with the discharged lubricant, limiting the effectiveness of continuous lubricant replenishment over extended periods.

[0010] The present invention was made in view of the above-mentioned problems, and its purpose is to provide a bearing device and a shaft device that can efficiently discharge the lubricant supplied to the bearing, maintain a good lubrication state, stably carry out long-term continuous operation, extend the bearing life, and facilitate maintenance.

[0011] Technical means to solve technical problems

[0012] The above-mentioned objective of the present invention is achieved by the following structure.

[0013] (1) A bearing assembly comprising: a housing; a rolling bearing supporting a shaft for rotation relative to the housing; and an outer ring positioning member embedded in the housing to axially position the outer ring of the rolling bearing, the bearing assembly supplying lubricant to the interior of the rolling bearing via a lubricant supply path.

[0014] At least one side of the outer ring is offset towards the axial center than the side of the inner ring of the rolling bearing.

[0015] An opening is formed on the end face of the outer ring positioning member that abuts against the offset side, allowing the outer ring positioning member to pass through radially.

[0016] (2) A rotating shaft device for a machine tool spindle, wherein the rotating shaft is supported by the bearing device described in (1) above and is rotatable.

[0017] (3) A shaft device for a high-speed electric motor, wherein the shaft is supported by the bearing device described in (1) above and is rotatable.

[0018] Invention Effects

[0019] The bearing device according to the present invention can efficiently discharge the lubricant supplied to the bearing, maintain a good lubrication state, stably carry out long-term continuous operation, and achieve a long bearing life.

[0020] Furthermore, in the spindle device for machine tool spindles and the spindle device for high-speed motors according to the present invention, the spindle is supported by the aforementioned bearing device and can rotate freely. Therefore, the stirring resistance of the lubricant generated along with the rotation of the spindle can be reduced, thereby suppressing the temperature rise and torque increase of the bearing, achieving a longer bearing life, and making maintenance easier. Attached Figure Description

[0021] Figure 1 This is a cross-sectional view of a spindle assembly for a machine tool, which applies a bearing assembly according to the first embodiment of the present invention.

[0022] Figure 2 yes Figure 1 Enlarged view of the main parts of the bearing assembly shown.

[0023] Figure 3 yes Figure 2 An enlarged sectional view of the second row of rolling bearings from the axial front in the four rolling bearings of the rear assembly shown.

[0024] Figure 4 This is a cross-sectional view of the main part of the bearing device according to the second embodiment of the present invention.

[0025] Figure 5 yes Figure 4 An enlarged sectional view of the rolling bearing shown.

[0026] Figure 6 This is a cross-sectional view of the main part of the bearing device according to the third embodiment of the present invention.

[0027] Figure 7 yes Figure 6 An enlarged sectional view of the rolling bearing shown.

[0028] Figure 8 This is an enlarged sectional view of the rolling bearing in the first modified example.

[0029] Figure 9 This is an enlarged sectional view of the rolling bearing in the second variation.

[0030] Figure 10 (a) and (b) are the top view and front view of the outer ring positioning component.

[0031] Figure 11 (a) and (b) are the top view and front view of the outer ring positioning component of the modified example.

[0032] Figure 12This is an enlarged cross-sectional view of the main part of the bearing device according to the fourth embodiment of the present invention.

[0033] Figure 13 (a) and (b) are Figure 12 The top view and front view of the outer ring positioning component are shown.

[0034] Figure 14 This is an enlarged cross-sectional view of the main part of the bearing device according to the fifth embodiment of the present invention.

[0035] Figure 15 This is an enlarged cross-sectional view of the main part of the bearing device according to the sixth embodiment of the present invention.

[0036] Figure 16 This is an enlarged cross-sectional view of the bearing device according to the seventh embodiment of the present invention. Detailed Implementation

[0037] Hereinafter, bearing devices and shaft devices according to various embodiments of the present invention will be described in detail based on the accompanying drawings. Furthermore, the bearing devices of each embodiment will be described in the case of application to shaft devices for machine tool spindles, but they can also be applied to shaft devices for high-speed electric motors.

[0038] (First Implementation)

[0039] Figure 1 This is a cross-sectional view showing a spindle assembly 200 for a machine tool spindle that incorporates the front bearing assembly 10 of the first embodiment of the present invention.

[0040] like Figure 1 As shown, the rotating shaft device 200 is a rotating shaft device with the electric motor built-in. The rotating shaft 60 is supported by a front bearing device 10 disposed in front of the electric motor 70 and a rear bearing device 110 disposed behind the electric motor 70, allowing it to rotate freely relative to the housing 50. The front bearing device 10 has four rolling bearings 20 assembled on the back, and the rear bearing device 110 has one rolling bearing 120. Of course, the number and arrangement of the multiple rolling bearings 20 are not limited to this.

[0041] The rear bearing assembly 110 is a bearing assembly that supplies lubricant G to the interior of the rolling bearing 120 via the lubricant supply path 52, and includes: the rolling bearing 120, which is a cylindrical roller bearing that supports the rotating shaft 60 for rotation relative to the housing 50; outer ring pressing members 140A and 140B, which are outer ring positioning members embedded in the housing 50 and axially positioning the outer ring 122 of the rolling bearing 120; and inner ring spacers 130A and 130B, which are externally embedded in the rotating shaft 60 and axially positioning the inner ring 121 of the rolling bearing 120.

[0042] Figure 2 yes Figure 1 Enlarged view of the main part of the front bearing assembly 10 shown. Figure 3 yes Figure 2 An enlarged sectional view of the second row of rolling bearings 20 from the axial front in the back assembly shown.

[0043] like Figure 2 As shown, the front bearing device 10 of this first embodiment is a bearing device that supplies lubricant G to the interior of the rolling bearing 20 via the lubricant supply path 52, and includes: a housing 50; a rolling bearing 20 that supports the rotating shaft 60 so that it can rotate freely relative to the housing 50; an outer ring spacer 40 and an outer ring pressing member 40B, which are outer ring positioning members embedded in the housing 50 to position the outer ring 22 of the rolling bearing 20 axially; and an inner ring spacer 30 that is externally embedded in the rotating shaft 60 to position the inner ring 21 of the rolling bearing 20 axially.

[0044] The housing 50 has multiple lubricant supply paths 52 that communicate with the oil supply holes 26 of the outer rings 22 of each rolling bearing 20 and the oil supply holes 126 of the outer rings 122 of the rolling bearing 120 from the axial rearward side of the housing 50. A lubricant supply section 201 is provided on the outside of the housing 50, and an opening 202 for the passage of the piping from the lubricant supply section 201 or a relay connector for relaying the piping from the lubricant supply section 201 is provided on the axial rear end face of the housing 50.

[0045] Therefore, by connecting the lubricant supply unit 201 to the opening 202, lubricant G is supplied to the bearing spaces of the multiple rolling bearings 20 via multiple lubricant supply paths 52. Furthermore, the lubricant supply unit 201 is connected to the opening 203 provided on the axial rear end face of the outer ring spacer pressing member 140A, and lubricant G is supplied to the bearing spaces of the rolling bearings 120 via the lubricant supply path 52, which includes a communicating hole 204 formed in the outer ring pressing member 140A.

[0046] like Figure 3 As shown, the four rolling bearings 20 assembled on the back are angular contact ball bearings, each having an inner ring 21, an outer ring 22, rolling elements (i.e., multiple balls 23) that are freely arranged between the inner ring raceway surface 21a of the inner ring 21 and the outer ring raceway surface 22a of the outer ring 22, and a cage 24 that freely holds the multiple balls 23. The outer ring 22 has a portion on the axial side relative to the outer ring raceway surface 22a (…). Figure 3 The inner circumferential surface of the middle (left side) has a conical countersunk hole 25 and an oil supply hole 26 that is radially through and opens near the countersunk hole 25 on the outer raceway surface 22a.

[0047] Furthermore, as described later, the outer ring 22 shortens from its axial back side to its axial center side, making it difficult to guide the cage 24 through the inner circumferential surface of the outer ring 22. Therefore, the cage 24 in this first embodiment can be guided by a ball bearing 23 or by an inner ring 21.

[0048] In addition, in each of the first embodiments of the rolling bearings, one side (axial end face on the back side) 22b of the outer ring 22 is offset by a dimension δ from the side (axial end face on the back side) 21b of the inner ring 21 towards the axial center.

[0049] That is, the axial positions of the axial end faces on the front side of the outer ring 22 and the inner ring 21 of the rolling bearing 20 are the same, while the axial positions of the axial end faces on the back side of the outer ring 22 and the inner ring 21 are different, and the width of the outer ring 22 is shorter than the width of the inner ring 21. Therefore, the bearing space between the outer circumferential surface of the inner ring 21 and the inner circumferential surface of the outer ring 22 becomes a structure that opens the axial back side radially outward.

[0050] Furthermore, an opening (discharge hole) 41 is formed on the end face 43 of the outer ring spacer 40 and the outer ring pressing member 40B, which abut against one side 22b of the offset outer ring 22. The opening 41 radially penetrates the outer ring spacer 40 or the outer ring pressing member 40B. In addition, a storage space 51 for storing lubricant G discharged from the interior of the rolling bearing 20 is provided on the housing 50 radially outside the opening 41.

[0051] The storage space 51 is an annular space formed on the outer periphery of the opening 41. Therefore, the bearing space of the rolling bearing 20 is connected to the storage space 51 via the radially outward opening portion on the axial back side of the outer ring 22 and the opening 41.

[0052] In the front bearing assembly 10 configured in this way, lubricant G supplied from the lubricant supply section 201 is supplied to the rolling bearing 20 via the lubricant supply path 52 and the oil supply hole 26 of the outer ring 22. For example, if the lubricant G is grease, a predetermined amount of grease is replenished periodically at predetermined intervals. The lubricant G supplied to the interior of the rolling bearing 20 lubricates various parts of the rolling bearing 20, and a portion of it remains inside the rolling bearing 20. Unnecessary lubricant G remaining inside the rolling bearing 20 is forced out and discharged to the outside of the rolling bearing 20.

[0053] In addition, a portion of the lubricant G that is no longer needed is thrown out radially outward by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and is forcibly and continuously discharged into the storage space 51 through the radially outward open portion and opening 41 on the axial back side of the outer ring 22 and accumulated in the storage space 51.

[0054] That is, one side 22b of the outer ring 22 of the rolling bearing 20 is offset from the axial center by an amount δ compared to the side 21b of the inner ring 21, forming a radially outward-open portion on the axial back side of the outer ring 22. Therefore, the lubricant G retained inside the rolling bearing 20 can be quickly discharged into the opening 41, and abnormal temperature rise caused by the lubricant G re-entering the inner ring raceway surface 21a and the outer ring raceway surface 22a of the rolling bearing 20 can be suppressed.

[0055] Furthermore, the discharge from the radially outward-opening portion on the axial back side of the outer ring 22 allows for a balance between the supply and discharge of lubricant G depending on the rotational speed of the rolling bearing 20. For example, at high speeds, to prevent premature damage caused by lubricant G depletion due to heat, the supply of lubricant G needs to be increased. However, if the supply is excessively increased, lubricant G becomes excessive, potentially leading to unstable temperature rise or abnormal heat generation. However, due to the high-speed rotation of the inner ring 21 and cage 24, the centrifugal force is large, and correspondingly, the discharge of lubricant G also increases. Therefore, even with an increased supply, the amount of lubricant G remaining inside the rolling bearing 20 does not increase, ensuring that an appropriate amount of lubricant G is retained inside and near the rolling bearing 20.

[0056] On the other hand, at low rotation speeds, even with a reduced supply, the centrifugal force on the inner ring 21 and cage 24 is small, so the discharge of lubricant G does not increase, and no excess lubricant G is discharged. Thus, by making the width of the outer ring 22 shorter than the width of the inner ring 21 and providing a radially outward-open portion in the bearing space, the supply and discharge of lubricant G are appropriately linked according to the rotation speed, ensuring a consistently good lubrication environment.

[0057] Furthermore, as a lubricant G, both grease and oil are effective, and heat generation can be suppressed by reducing stirring resistance. Additionally, when the storage space 51 is full of lubricant G, it needs to be discharged to the outside of the forward bearing assembly 10. However, according to this embodiment, a discharge channel (not shown) is provided that connects the storage space 51, located in the housing 50, to the external space. By suction from the outside, almost all of the lubricant G can be discharged, thus simplifying maintenance. The discharge channel to the external space is particularly effective in the case of oil-lubricated applications.

[0058] As explained above, in the front bearing assembly 10 of this first embodiment, the lubricant G supplied to the interior of the rolling bearing 20 is thrown away from the radially outward-opening portion of the outer ring 22 by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and accumulates in the storage space 51 through the opening 41. This reduces the stirring resistance of the lubricant G, suppresses heat generation, maintains good lubrication, and as a result, extends the lifespan of the rolling bearing 20. Furthermore, the magnitude of the centrifugal force that throws away the lubricant G varies according to the rotational speed of the rolling bearing 20, i.e., the inner ring 21 and the cage 24, thus enabling appropriate lubricant supply corresponding to the rotational speed.

[0059] Furthermore, according to the spindle rotating device 200 of the machine tool spindle that applies the front bearing device 10 of the first embodiment, the rotating shaft 60 of the high-speed rotating machine tool spindle rotating device can be supported by the rolling bearing 20 with a long service life, making maintenance easier.

[0060] Of course, when the front bearing device 10 of this first embodiment is applied to the shaft device for a high-speed motor, the shaft of the high-speed motor shaft device that rotates at high speed can also be supported by the rolling bearing 20 that has achieved a long service life, making maintenance easier.

[0061] (Second Implementation)

[0062] Figure 4 This is a cross-sectional view of the main part of the front bearing device 10A according to the second embodiment of the present invention. Figure 5 yes Figure 4 An enlarged sectional view of the rolling bearing 20A shown.

[0063] like Figure 4 As shown, the front bearing device 10A of this second embodiment is a bearing device that supplies lubricant G to the interior of the rolling bearing 20A via the lubricant supply path 52, and the front bearing device 10A includes a housing 50, a rolling bearing 20A, an outer ring spacer 40 and an outer ring pressing member 40B as outer ring positioning members, and an inner ring spacer 30.

[0064] like Figure 5 As shown, the four rolling bearings 20A assembled on the back are angular contact ball bearings, each having an inner ring 21, an outer ring 22A, a plurality of balls 23 that are freely arranged between the inner ring raceway surface 21a of the inner ring 21 and the outer ring raceway surface 22a of the outer ring 22A, and a cage 24. The outer ring 22A has a portion on the axial side relative to the outer ring raceway surface 22a (…). Figure 5 The inner circumferential surface of the left side of the ring has a conical countersunk hole 25 and an oil supply hole 26 that is radially through and opens near the countersunk hole 25 on the outer ring raceway surface 22a.

[0065] In addition, in each of the second embodiments of the rolling bearings 20A, one side (axial end face on the front side) 22c of the outer ring 22A is offset towards the axial center by an amount σ compared to the side (axial end face on the front side) 21c of the inner ring 21.

[0066] That is, the axial positions of the axial end faces on the back side of the outer ring 22A and the inner ring 21 of the rolling bearing 20A are the same, while the axial positions of the axial end faces on the front side of the outer ring 22A and the inner ring 21 are different, and the width of the outer ring 22A is shorter than the width of the inner ring 21. Therefore, the bearing space between the outer circumferential surface of the inner ring 21 and the inner circumferential surface of the outer ring 22A becomes a structure that opens the axial front side radially outward.

[0067] Furthermore, an opening 41 is formed on the end face 44 of the outer ring spacer 40 and the outer ring pressing member 40B, which abut against one side 22c of the offset outer ring 22A, allowing the outer ring spacer 40 or the outer ring pressing member 40B to pass through radially. Additionally, a storage space 51 for storing lubricant G discharged from the interior of the rolling bearing 20A is provided on the housing 50 radially outside the opening 41. Therefore, the bearing space of the rolling bearing 20A communicates with the storage space 51 via the radially outward-opening portion on the axial front side of the outer ring 22A and the opening 41.

[0068] In the front bearing assembly 10A configured in this way, lubricant G supplied from the lubricant supply section 201 is supplied to the rolling bearing 20A via the lubricant supply path 52 and the oil supply hole 26 of the outer ring 22A. For example, if the lubricant G is grease, a predetermined amount of grease is replenished periodically at predetermined intervals. The lubricant G supplied to the interior of the rolling bearing 20A lubricates various parts of the rolling bearing 20A, and a portion of it remains inside the rolling bearing 20A. The unwanted lubricant G remaining inside the rolling bearing 20A is forced out and discharged to the outside of the rolling bearing 20A.

[0069] In addition, a portion of the lubricant G that is no longer needed is thrown out radially outward by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and is forcibly and continuously discharged into the storage space 51 through the radially outward open portion and opening 41 on the axial front side of the outer ring 22A and accumulated in the storage space 51.

[0070] That is, one side 22c of the outer ring 22A of the rolling bearing 20A is offset σ from the axial center side compared to the side 21c of the inner ring 21, forming a radially outward-open portion of the axial front side of the outer ring 22A. Therefore, the lubricant G retained inside the rolling bearing 20A can be quickly discharged into the opening 41, and abnormal temperature rise caused by the lubricant G re-entering the inner ring raceway surface 21a and the outer ring raceway surface 22a of the rolling bearing 20A can be suppressed.

[0071] Therefore, similar to the front bearing assembly 10 of the first embodiment described above, in the front bearing assembly 10A of this second embodiment, the lubricant G supplied to the interior of the rolling bearing 20A is thrown away from the radially outward-opening portion of the outer ring 22A by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and accumulates in the storage space 51 through the opening 41. As a result, the stirring resistance of the lubricant G is reduced, heat generation is suppressed, and a good lubrication condition is maintained, thereby extending the life of the rolling bearing 20A. Furthermore, the magnitude of the centrifugal force that throws away the lubricant G varies according to the rotational speed of the rolling bearing 20A, i.e., the inner ring 21 and the cage 24, thus enabling appropriate lubricant supply corresponding to the rotational speed.

[0072] Furthermore, since the axial back side of the outer ring 22A does not shorten towards the axial center side, the inner circumferential surface of the outer ring 22A can be used to guide the cage 24. Therefore, in addition to ball-guided and inner-ring-guided methods, the cage 24 in this second embodiment can also be guided by the inner circumferential surface of the outer ring 22A in an outer-ring-guided method.

[0073] (Third implementation method)

[0074] Figure 6 This is a cross-sectional view of the main part of the front bearing device 10B according to the third embodiment of the present invention. Figure 7 yes Figure 6 An enlarged sectional view of the rolling bearing 20B shown.

[0075] like Figure 6 As shown, the front bearing device 10B of this third embodiment is a bearing device that supplies lubricant G to the interior of the rolling bearing 20B via the lubricant supply path 52. The front bearing device 10B includes a housing 50, a rolling bearing 20B, an outer ring spacer 40 and an outer ring pressing member 40B as outer ring positioning members, and an inner ring spacer 30.

[0076] like Figure 7As shown, the four rolling bearings 20B assembled on the back are angular contact ball bearings, each having an inner ring 21, an outer ring 22B, a plurality of balls 23 that are freely arranged between the inner ring raceway surface 21a of the inner ring 21 and the outer ring raceway surface 22a of the outer ring 22B, and a cage 24. The outer ring 22B has a tapered countersunk hole 25 on its inner circumferential surface on the axial side relative to the outer ring raceway surface 22a, and has an oil supply hole 26 that extends radially through and opens into the countersunk hole 25 near the outer ring raceway surface 22a.

[0077] In addition, in this third embodiment, the two sides 22b and 22c of the outer ring 22B of each rolling bearing 20B are offset by the dimensions δ and σ, respectively, from the axial center side compared to the two sides 21b and 21c of the inner ring 21.

[0078] That is, the axial positions of the axial end faces on the back side and front side of the outer ring 22B and the inner ring 21 of the rolling bearing 20B are different, and the width of the outer ring 22B is shorter than the width of the inner ring 21. As a result, the bearing space between the outer circumferential surface of the inner ring 21 and the inner circumferential surface of the outer ring 22B becomes a structure that opens the axial back side and the axial front side radially outward.

[0079] Furthermore, openings 41 are formed on the end faces 43 and 44 of the outer ring spacer 40 and the outer ring pressing member 40B, which abut against the two sides 22b and 22c of the offset outer ring 22B, respectively, allowing the outer ring spacer 40 or the outer ring pressing member 40B to pass through radially. Additionally, a storage space 51 for storing lubricant G discharged from the interior of the rolling bearing 20A is provided on the housing 50 radially outside the opening 41. Therefore, the bearing space of the rolling bearing 20B communicates with each storage space 51 via the radially outward-opening portions on the axial back side and axial front side of the outer ring 22A and the openings 41.

[0080] In the front bearing assembly 10B configured in this way, lubricant G supplied from the lubricant supply section 201 is supplied to the rolling bearing 20B via the lubricant supply path 52 and the oil supply hole 26 of the outer ring 22B. For example, if the lubricant G is grease, a predetermined amount of grease is replenished periodically at predetermined intervals. The lubricant G supplied to the interior of the rolling bearing 20B lubricates various parts of the rolling bearing 20B, and a portion of it remains inside the rolling bearing 20B. Unnecessary lubricant G in the lubricant G remaining inside the rolling bearing 20B is forced out and discharged to the outside of the rolling bearing 20B.

[0081] In addition, a portion of the lubricant G that is no longer needed is thrown out radially outward by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24. It is forced and continuously discharged into each storage space 51 through the radially outward open portion and opening 41 of the axial back side and axial front side of the outer ring 22B and accumulated in each storage space 51.

[0082] That is, the two sides 22b and 22c of the outer ring 22B of the rolling bearing 20B are offset from the two sides 21b and 21c of the inner ring 21 by dimensions δ and σ, respectively, forming radially outward-open portions on the axial back side and axial front side of the outer ring 22B. Therefore, the lubricant G retained inside the rolling bearing 20B can be quickly discharged through the opening 41, and abnormal temperature rise caused by the lubricant G re-entering the inner ring raceway surface 21a and the outer ring raceway surface 22a of the rolling bearing 20B can be suppressed.

[0083] Therefore, similar to the front bearing assembly 10 of the first embodiment described above, in the front bearing assembly 10B of this third embodiment, the lubricant G supplied to the inside of the rolling bearing 20B is thrown away from the radially outward-opening portion of the outer ring 22B on both the axial back side and the axial front side by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and accumulates in each storage space 51 through the opening 41. As a result, the stirring resistance of the lubricant G is reduced, heat generation is suppressed, and a good lubrication state is maintained, thereby extending the life of the rolling bearing 20B. Furthermore, the magnitude of the centrifugal force that throws away the lubricant G varies according to the rotational speed of the rolling bearing 20B, i.e., the inner ring 21 and the cage 24, thus enabling appropriate lubricant supply corresponding to the rotational speed.

[0084] It should be noted that the axial back side and axial front side of the outer ring 22B are shortened towards the axial center side, making it difficult to guide the cage 24 using the inner circumferential surface of the outer ring 22B. Therefore, the cage 24 in this third embodiment is guided by a ball bearing and an inner ring bearing.

[0085] It should be noted that in the front bearing devices 10, 10A, and 10B of the first to third embodiments described above, the offset dimensions δ and σ of the four rolling bearings 20, 20A, and 20B assembled on the back side are all set to be the same. However, if the level of abnormal temperature rise varies depending on the configuration of the rolling bearings, the offset dimensions δ and σ can be appropriately changed respectively.

[0086] For example, in the case that abnormal heating is more likely to occur in the first and fourth columns of the four rolling bearings in the back assembly, while abnormal heating is less likely to occur in the second and third columns, the offset dimensions δ and σ of the rolling bearings 20, 20A, and 20B in the first and fourth columns can be larger than the offset dimensions δ and σ of the rolling bearings 20, 20A, and 20B in the second and third columns.

[0087] In addition, it is possible to set the offset dimension δ (or σ) for one or more rolling bearings among a plurality of rolling bearings, or to make the offset dimension δ (or σ) of one or more rolling bearings among a plurality of rolling bearings vary relative to the offset dimension δ (or σ) of the remaining rolling bearings.

[0088] (A variation of a rolling bearing)

[0089] Figure 8 This is an enlarged sectional view of the rolling bearing 20C in the first modified example. Figure 9 This is an enlarged sectional view of the rolling bearing 20D in the second variation.

[0090] like Figure 8 As shown, in the first modified example, the outer ring 22C of the rolling bearing 20C is located on the axial side relative to the outer ring raceway surface 22a. Figure 8 The inner circumferential surface (on the left side) has a conical countersunk hole 25, and has a radially penetrating hole on the other side of the axial direction near the outer raceway surface 22a. Figure 8 Oil supply hole 26 is an opening on the inner circumferential surface of the right side of the middle.

[0091] Furthermore, one side (axial end face on the front side) 22c of the outer ring 22C of the rolling bearing 20C is offset towards the axial center by an amount σ compared to the side (axial end face on the front side) 21c of the inner ring 21. That is, the outer ring 22C and the back side of the inner ring 21 of the rolling bearing 20C are offset towards the axial center by an amount σ. Figure 8 The axial positions of the axial end faces of the outer ring 22C and the inner ring 21 are the same on the right side. Figure 8 The axial positions of the axial end faces (on the left side of the inner ring 21) are different, and the width of the outer ring 22C is shorter than the width of the inner ring 21. Therefore, the bearing space between the outer circumferential surface of the inner ring 21 and the inner circumferential surface of the outer ring 22C becomes a structure that opens the axial front side to the radial outside.

[0092] In the rolling bearing 20C of this first modification, the oil supply hole 26 for supplying lubricant G is provided on the back side of the outer ring 22C. Therefore, the lubricant G supplied to the interior of the rolling bearing 20C through the oil supply hole 26 provided on the back side of the outer ring 22C lubricates various parts of the rolling bearing 20C, and a portion of it remains inside the rolling bearing 20C. A portion of the lubricant G that is no longer needed within the rolling bearing 20C is thrown outwards through the radially outward-opening portion provided on the front side of the outer ring 22C and discharged into the opening 41.

[0093] Furthermore, the outer ring 22C has an oil supply hole 26 on its axial back side, making it difficult to guide the cage 24 using the inner circumferential surface of the outer ring 22C. Therefore, the cage 24 in this first modified example can be guided by a ball bearing or an inner ring bearing.

[0094] like Figure 9 As shown, in the second modified example of the rolling bearing 20D, the inner ring 21D is located on the axial side relative to the inner ring raceway surface 21a. Figure 9 The inner circumferential surface of the outer ring 22D (left side) has a conical countersunk hole 25D, and the outer ring 22D has an oil supply hole 26 that is radially through and opens on the inner circumferential surface on the axial side near the outer ring raceway surface 22a.

[0095] Furthermore, one side (axial end face on the back side) 22c of the outer ring 22D of the rolling bearing 20D is offset towards the axial center by an amount σ compared to the side (axial end face on the back side) 21c of the inner ring 21D. That is, the front side (front side) of the outer ring 22D and the inner ring 21D of the rolling bearing 20D are offset towards the axial center by an amount σ. Figure 9 The axial positions of the axial end faces of the outer ring 22D and the inner ring 21D are the same. Figure 9 The axial positions of the axial end faces (on the left side of the inner ring 21D) are different, and the width of the outer ring 22D is shorter than the width of the inner ring 21D. Therefore, the bearing space between the outer circumferential surface of the inner ring 21D and the inner circumferential surface of the outer ring 22D becomes a structure that opens the axial back side to the radially outward.

[0096] In the rolling bearing 20D of this second variation, the countersunk hole 25D is provided in the inner ring 21D.

[0097] Furthermore, the axial front side of the outer ring 22D does not shorten towards the axial center side, thus the inner circumferential surface of the outer ring 22D can be used for guiding the cage 24. Therefore, in addition to ball-guided and inner-ring-guided types, the cage 24 in this second modification example can also be guided by an outer ring-guided type.

[0098] (Outer ring positioning component)

[0099] like Figure 10As shown in (a) and (b), the outer ring spacer 40, which serves as an outer ring positioning component in the bearing device of this embodiment, is formed as an annular shape embedded in the housing 50.

[0100] Furthermore, in the outer ring spacer 40, a portion of the circumferential direction is rectangularly cut away along the axial direction from the end face 44 that abuts against the side of the outer ring 22, thereby forming a plurality of radially penetrating openings 41 with a circumferential width w. It is preferable that the openings 41 of the outer ring spacer 40 are formed at equal intervals in the circumferential direction, but at least one is sufficient.

[0101] Alternatively, it can be like Figure 11 As shown in (a) and (b), the radially penetrating opening 41c is formed into a semi-circular shape, similar to the outer ring spacer 40C. The opening in this embodiment is not limited to these rectangular or semi-circular shapes; various opening shapes can be used as long as lubricant that can be thrown outward from the radially outward opening portion of at least one axial end face side of the outer ring toward the outer diameter side can be discharged.

[0102] Furthermore, the outer ring positioning component in the bearing device of this embodiment also includes an outer ring pressing member 40B that is bolted to the front side of the housing 50. Therefore, the end face 44 of the outer ring pressing member 40B, which abuts against the side of the outer ring 22, is also formed with a plurality of radially penetrating openings by cutting out in a rectangular shape in the axial direction.

[0103] (Fourth Implementation)

[0104] Figure 12 This is an enlarged cross-sectional view of the main part of the front bearing device 10C according to the fourth embodiment of the present invention. Figure 13 (a) and (b) are Figure 12 The top and front views of the outer ring spacer 40E are shown.

[0105] like Figure 12 As shown, the front bearing device 10C of this fourth embodiment is a bearing device that supplies lubricant G to the interior of the rolling bearing 20E via the lubricant supply path 52, and the front bearing device 10C includes: a housing 50A; a rolling bearing 20E that supports the rotating shaft 60 so that it can rotate freely relative to the housing 50A; an outer ring spacer 40E and an outer ring pressing member 40F, which are outer ring positioning members embedded in the housing 50A to position the outer ring 22E of the rolling bearing 20E in the axial direction; and an inner ring spacer 30 that is externally embedded in the rotating shaft 60 to position the inner ring 21 of the rolling bearing 20E in the axial direction.

[0106] The rolling bearings 20E are angular contact ball bearings, and include an inner ring 21, an outer ring 22E, a plurality of rolling elements, namely balls 23, which are freely arranged between the inner ring raceway surface 21a of the inner ring 21 and the outer ring raceway surface 22a of the outer ring 22E, and a cage 24 that holds the plurality of balls 23 in a rotatable manner.

[0107] The outer ring 22E is on the axial side relative to the outer ring raceway surface 22a. Figure 12 The inner circumferential surface of the outer ring 22E (on the left side) has a conical countersunk hole 25. In addition, one side (axial end face on the front side) 22c of the outer ring 22E is offset towards the axial center by an amount σ compared to the side (axial end face on the front side) 21c of the inner ring 21.

[0108] That is, the axial positions of the axial end faces on the back side of the outer ring 22E and the inner ring 21 of the rolling bearing 20E are the same, while the axial positions of the axial end faces on the front side of the outer ring 22E and the inner ring 21 are different, and the width of the outer ring 22E is shorter than the width of the inner ring 21. Therefore, the bearing space between the outer circumferential surface of the inner ring 21 and the inner circumferential surface of the outer ring 22E becomes a structure that opens the axial front side radially outward.

[0109] Moreover, such as Figure 13 As shown, an opening 41 is formed on the end face 44 of the outer ring spacer 40E (outer ring pressing member 40F) that abuts against one side 22c of the offset outer ring 22E, allowing the outer ring spacer 40E (outer ring pressing member 40F) to pass through radially. Furthermore, the outer ring spacer 40E (outer ring pressing member 40F) has an oil supply hole 42 that passes through radially and opens near the countersunk hole 25.

[0110] In the front bearing assembly 10C configured in this way, the lubricant G, which is composed of grease, supplied from the lubricant supply section 201, is supplied to the rolling bearing 20E via the lubricant supply path 52 and the oil supply hole 42 of the outer ring spacer 40E.

[0111] The lubricant G supplied to the interior of the rolling bearing 20E lubricates all parts of the rolling bearing 20E, and a portion of it remains inside the rolling bearing 20E. The lubricant G that is no longer needed in the lubricant G that remains inside the rolling bearing 20E is forced out and discharged to the outside of the rolling bearing 20E.

[0112] In addition, a portion of the lubricant G that is no longer needed is thrown out radially outward by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and is forced and continuously discharged into the storage space 51 through the radially outward open portion of the axial front side of the outer ring 22E and the opening 41 and stored in the storage space 51.

[0113] That is, one side 22c of the outer ring 22E of the rolling bearing 20E is offset from the axial center by a dimension σ compared to the side 21c of the inner ring 21, forming a radially outward-open portion of the axial front side of the outer ring 22E. Therefore, the lubricant G retained inside the rolling bearing 20E can be quickly discharged into the opening 41, and abnormal temperature rise caused by the lubricant G re-entering the inner ring raceway surface 21a and the outer ring raceway surface 22a of the rolling bearing 20E can be suppressed.

[0114] Therefore, similar to the front bearing assembly 10 of the first embodiment described above, in the front bearing assembly 10C of this fourth embodiment, the lubricant G supplied to the interior of the rolling bearing 20E is thrown away from the radially outward-opening portion of the outer ring 22E by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and accumulates in each storage space 51 through the opening 41. As a result, the stirring resistance of the lubricant G is reduced, heat generation is suppressed, and a good lubrication condition is maintained. Consequently, the life of the rolling bearing 20E is extended.

[0115] Furthermore, since the axial back side of the outer ring 22E does not shorten towards the axial center, the inner circumferential surface of the outer ring 22E can be used for guiding the cage 24. Therefore, in addition to ball-guided and inner-ring-guided methods, the cage 24 of this fourth embodiment can also be guided by an outer ring-guided method.

[0116] (Fifth implementation method)

[0117] Figure 14 This is an enlarged cross-sectional view of the main part of the front bearing device 10D according to the fifth embodiment of the present invention.

[0118] like Figure 14 As shown, the front bearing device 10D of this fifth embodiment is a bearing device that supplies lubricant G to the interior of the rolling bearing 20F via the lubricant supply path 52, and the front bearing device 10D includes a housing 50B, a rolling bearing 20F, outer ring spacers 40 and 40G as outer ring positioning members, and an inner ring spacer 30.

[0119] The rolling bearings 20F are angular contact ball bearings, and have an inner ring 21, an outer ring 22F, a plurality of rolling elements, namely balls 23, which are freely arranged between the inner ring raceway surface 21a of the inner ring 21 and the outer ring raceway surface 22a of the outer ring 22F, and a cage 24 that holds the plurality of balls 23 so that they can rotate freely.

[0120] The outer ring 22F is on the axial side relative to the outer ring raceway surface 22a. Figure 14The inner circumferential surface of the outer ring 22F (on the left side) has a conical countersunk hole 25. In addition, the two side surfaces 22b and 22c of the outer ring 22F are offset from the two side surfaces 21b and 21c of the inner ring 21 by the amount of δ and σ, respectively, towards the axial center.

[0121] That is, the axial positions of the axial end faces on the back side and front side of the outer ring 22F and inner ring 21 of the rolling bearing 20F are different, and the width of the outer ring 22F is shorter than the width of the inner ring 21. As a result, the bearing space between the outer circumferential surface of the inner ring 21 and the inner circumferential surface of the outer ring 22F becomes a structure that opens the axial back side and axial front side radially outward.

[0122] Furthermore, openings 41 are formed on the end faces 43 and 44 of the outer ring spacer 40G, which abut against the two sides 22b and 22c of the offset outer ring 22F, respectively, allowing the outer ring spacer 40G to pass through radially. In addition, an oil supply hole 45 is provided at the axial center of the outer ring spacer 40G for supplying lubricant G from the side of the adjacent rolling bearing 20F.

[0123] In the front bearing assembly 10D configured in this way, the lubricant G, which is composed of oil and gas supplied from the lubricant supply section 201, is supplied to the rolling bearing 20F via the lubricant supply path 52 and the oil supply hole 45 of the outer ring spacer 40G.

[0124] The lubricant G supplied to the interior of the rolling bearing 20F lubricates all parts of the rolling bearing 20F, and a portion of it remains inside the rolling bearing 20F. The lubricant G that is no longer needed inside the rolling bearing 20F is forced out and discharged to the outside of the rolling bearing 20F.

[0125] In addition, a portion of the lubricant G that is no longer needed is thrown out radially outward by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24. It is forced and continuously discharged into each storage space 51 through the radially outward open portion and opening 41 of the axial back side and axial front side of the outer ring 22F and accumulated in each storage space 51.

[0126] That is, the two sides 22b and 22c of the outer ring 22F of the rolling bearing 20F are offset from the two sides 21b and 21c of the inner ring 21 by dimensions δ and σ, respectively, forming radially outward-open portions on the axial back side and axial front side of the outer ring 22F. Therefore, the lubricant G retained inside the rolling bearing 20F can be quickly discharged through the opening 41, and abnormal temperature rise caused by the lubricant G re-entering the inner ring raceway surface 21a and the outer ring raceway surface 22a of the rolling bearing 20F can be suppressed.

[0127] Therefore, similar to the front bearing assembly 10 of the first embodiment described above, in the front bearing assembly 10D of this fifth embodiment, the lubricant G supplied to the inside of the rolling bearing 20F is thrown outward from the radially outward-opening portions of the outer ring 22F on both the axial back side and the axial front side by the centrifugal force generated by the rotational force of the inner ring 21 and the cage 24, and accumulates in each storage space 51 through the opening 41. As a result, the stirring resistance of the lubricant G is reduced, heat generation is suppressed, and a good lubrication state is maintained. Consequently, the life of the rolling bearing 20F is extended.

[0128] It should be noted that the axial back side and axial front side of the outer ring 22F are shortened towards the axial center side, making it difficult to guide the cage 24 using the inner circumferential surface of the outer ring 22F. Therefore, the cage 24 in this fifth embodiment can be guided by a ball bearing or an inner ring bearing.

[0129] (Sixth Implementation Method)

[0130] Figure 15 This is an enlarged sectional view of the main part of the front bearing device 10E according to the sixth embodiment of the present invention.

[0131] like Figure 15 As shown, the front bearing device 10E of this sixth embodiment is a bearing device that supplies lubricant G to the interior of the rolling bearing 20G via the lubricant supply path 52, and the front bearing device 10E includes a housing 50C, a rolling bearing 20G, an outer ring spacer 40G as an outer ring positioning member, and an inner ring spacer 30.

[0132] The rolling bearings 20G are angular contact ball bearings, and have an inner ring 21G, an outer ring 22G, a plurality of balls 23 that are freely arranged between the inner ring raceway surface 21a of the inner ring 21G and the outer ring raceway surface 22a of the outer ring 22F, and a cage 24.

[0133] The outer ring 22G is on the opposite side of the outer ring raceway surface 22a along the axial direction. Figure 15 The inner circumferential surface of the outer ring 22G (right side) has a conical countersunk hole 25. Furthermore, the side surface 22c of the outer ring 22G is offset towards the axial center by an amount σ compared to the side surface 21c of the inner ring 21G. Additionally, the side surface 22b of the outer ring 22G is offset towards the axial center by an amount δ compared to the side surface 21b of the inner ring 21G. The inner ring 21G faces the back side in a manner opposite to the circumferential groove 47 formed on the inner circumferential surface of the outer ring spacer 40G, as described later. Figure 15 (Left side of the middle) Extended settings.

[0134] That is, the axial positions of the axial end faces on the back side and the front side of the outer ring 22G and the inner ring 21G of the rolling bearing 20G are different, and the width of the outer ring 22G is shorter than the width of the inner ring 21G. As a result, the bearing space between the outer circumferential surface of the inner ring 21G and the inner circumferential surface of the outer ring 22G becomes a structure that opens the axial back side and the axial front side radially outward.

[0135] Furthermore, openings 41 are formed on the end faces 43 and 44 of the outer ring spacer 40G, which abut against the two side faces 22b and 22c of the offset outer ring 22F, respectively, allowing the outer ring spacer 40G to pass through radially. Additionally, an oil supply hole 46 for supplying lubricant G to the outer circumferential surface of the inner ring 21G of the adjacent rolling bearing 20G and a circumferential groove 47 communicating with the oil supply hole 46 are provided at the axial center of the outer ring spacer 40G. The circumferential groove 47 is formed on the inner circumferential surface of the outer ring spacer 40G in a manner opposite to the extended portion of the inner ring 21G.

[0136] In the front bearing assembly 10E configured in this way, the lubricant G, which is composed of oil and gas supplied from the lubricant supply section 201, is supplied to the outer peripheral surface of the inner ring 21G via the lubricant supply path 52, the oil supply hole 46 of the outer ring spacer 40G, and the circumferential groove 47.

[0137] Lubricant G supplied from the outer periphery of the inner ring 21G to the interior of the rolling bearing 20G lubricates various parts of the rolling bearing 20G, with a portion remaining inside the rolling bearing 20G. Unnecessary lubricant G remaining inside the rolling bearing 20G is forced out and discharged to the outside of the rolling bearing 20G.

[0138] In addition, a portion of the lubricant G that is no longer needed is thrown out radially outward by the centrifugal force generated by the rotational force of the inner ring 21G and the cage 24, and is forced and continuously discharged into each storage space 51 through the radially outward open portion and opening 41 of the axial back side and axial front side of the outer ring 22G and stored in each storage space 51.

[0139] That is, the two sides 22b and 22c of the outer ring 22G of the rolling bearing 20G are offset from the two sides 21b and 21c of the inner ring 21G by dimensions δ and σ, respectively, forming radially outward-open portions on the axial back side and axial front side of the outer ring 22G. Therefore, the lubricant G retained inside the rolling bearing 20G can be quickly discharged through the opening 41, and abnormal temperature rise caused by the lubricant G re-entering the inner ring raceway surface 21a and the outer ring raceway surface 22a of the rolling bearing 20G can be suppressed.

[0140] Therefore, similar to the front bearing assembly 10 of the first embodiment described above, in the front bearing assembly 10E of this sixth embodiment, the lubricant G supplied to the inside of the rolling bearing 20G is thrown away from the radially outward-opening portions of the outer ring 22G on the axial back side and axial front side by the centrifugal force generated by the rotational force of the inner ring 21G and the cage 24, and accumulates in each storage space 51 through the opening 41. As a result, the stirring resistance of the lubricant G is reduced, heat generation is suppressed, and a good lubrication condition is maintained. Consequently, the life of the rolling bearing 20G is extended.

[0141] Furthermore, the outer ring 22G is shorter towards the axial center from both the axial back side and the axial front side, making it difficult to guide the cage 24 using the inner circumferential surface of the outer ring 22G. Therefore, the cage 24 in this sixth embodiment can be guided by a ball bearing or an inner ring bearing.

[0142] (Seventh Implementation)

[0143] Figure 16 This is an enlarged cross-sectional view of the rear bearing device 110A according to the seventh embodiment of the present invention.

[0144] like Figure 16 As shown, the rear bearing device 110A of this seventh embodiment is a bearing device that supplies lubricant G to the interior of the rolling bearing 120A via the lubricant supply path 152, and the rear bearing device 110A includes the rolling bearing 120A that supports the rotating shaft 60 so that it can rotate freely relative to the housing 50, the outer ring pressing members 140C and 140D as outer ring positioning members, and the inner ring spacers 130A and 130B.

[0145] Rolling bearing 120A is a cylindrical roller bearing, comprising an inner ring 121 with two flanges, an outer ring 122 without flanges, a plurality of rolling elements 123 which are freely disposed between the inner ring raceway surface 121a of the inner ring 121 and the outer ring raceway surface 122a of the outer ring 122, and a cage (not shown). The outer ring 122 has an oil supply hole 126 that extends radially through and opens toward the front of the inner circumferential surface of the outer ring 122.

[0146] Furthermore, in this seventh embodiment, one side (rear axial end face) 122b of the outer ring 122 of the rolling bearing 120A is offset by a dimension δ from the side 121b of the inner ring 121 towards the axial center.

[0147] That is, the axial positions of the front axial end faces of the outer ring 122 and inner ring 121 of the rolling bearing 120A are the same, while the axial positions of the rear axial end faces of the outer ring 122 and inner ring 121 are different, and the width of the outer ring 122 is shorter than the width of the inner ring 121. Therefore, the bearing space between the outer circumferential surface of the inner ring 121 and the inner circumferential surface of the outer ring 122 becomes the space between the axial rear ( Figure 16 The structure that opens radially outward (on the right side of the structure).

[0148] Furthermore, an opening (discharge hole) 141 is formed on the end face 143 of the outer ring pressing member 140C, which abuts against one side 122b of the offset outer ring 122, allowing the outer ring pressing member 140C to pass through radially. In addition, a storage space 151 is provided on the outer ring pressing member 140D radially outside the opening 141, which is capable of storing the lubricant G discharged from the interior of the rolling bearing 120A.

[0149] The storage space 151 is an annular space formed on the outer periphery of the opening 141. Therefore, the bearing space of the rolling bearing 120A is connected to the storage space 151 via the radially outward opening portion on the axial rear side of the outer ring 122 and the opening 141.

[0150] In the rear bearing assembly 110A configured in this way, lubricant G supplied from the lubricant supply section 201 is supplied to the rolling bearing 120A via the lubricant supply path 152 and the oil supply hole 126 of the outer ring 122. For example, if the lubricant G is grease, a predetermined amount of grease is replenished periodically at predetermined intervals. The lubricant G supplied to the interior of the rolling bearing 120A lubricates various parts of the rolling bearing 120A, and a portion of it remains inside the rolling bearing 120A. Unnecessary lubricant G in the lubricant G remaining inside the rolling bearing 120A is forced out and discharged to the outside of the rolling bearing 120A.

[0151] In addition, a portion of the lubricant G that is no longer needed is thrown out radially outward by the centrifugal force generated by the rotational force of the inner ring 121 and the cage, and is forcibly and continuously discharged into the storage space 151 through the radially outward open portion and opening 141 on the axial rear side of the outer ring 122 and accumulated in the storage space 151.

[0152] That is, one side 122b of the outer ring 122 of the rolling bearing 120A is offset δ towards the axial center than the side 121b of the inner ring 121, forming a radially outward-open portion on the axial rear side of the outer ring 122. Therefore, the lubricant G retained inside the rolling bearing 120A can be quickly discharged into the opening 141, and abnormal temperature rise caused by the lubricant G re-entering the inner ring raceway surface 121a and the outer ring raceway surface 122a of the rolling bearing 120A can be suppressed.

[0153] Therefore, similar to the front bearing assembly 10 of the first embodiment described above, in the rear bearing assembly 110A according to this seventh embodiment, the lubricant G supplied to the interior of the rolling bearing 120A is thrown away from the radially outward opening portion of the outer ring 122 by the centrifugal force generated by the rotational force of the inner ring 121 and the cage, and accumulates in the storage space 151 through the opening 141. As a result, the stirring resistance of the lubricant G is reduced, heat generation is suppressed, and a good lubrication state is maintained, thereby extending the life of the rolling bearing 120A. Furthermore, the magnitude of the centrifugal force that throws away the lubricant G varies according to the rotational speed of the rolling bearing 120A, i.e., the inner ring 121 and the cage, thus allowing for appropriate lubricant supply in accordance with the rotational speed.

[0154] It should be noted that, similar to the rolling bearings in the above embodiments, the two sides 122b and 122c of the outer ring 122 in the rolling bearing 120A can be offset from the two sides 121b and 121c of the inner ring 121 towards the axial center by the amounts of δ and σ, respectively, or the oil supply hole 126 of the outer ring 122 can be made to open towards the front side of the outer ring 122, or the oil supply structure of the lubricant G to the rolling bearing 120A can be changed appropriately, which is self-evident.

[0155] Furthermore, the present invention is not limited to the embodiments described above, and can be appropriately modified and improved. Moreover, the material, shape, size, quantity, and arrangement of the constituent elements in the above embodiments are arbitrary and not limited, as long as they enable the realization of the present invention.

[0156] Here, the features of the above-described embodiments of the bearing device and shaft device of the present invention are briefly summarized and listed in [1] to [4].

[0157] [1] A bearing assembly (front bearing assembly 10, 10A, 10B, 10D, 10E, rear bearing assembly 110A) comprising: a housing (50, 50A, 50B, 50C); rolling bearings (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A) supporting a rotating shaft (60) for rotational freedom relative to the housing; and outer ring positioning members (outer ring spacers 40, outer ring pressing members 40B, 140C) embedded in the housing to axially position the outer rings (22, 22A, 22B, 22C, 22D, 22E, 22F, 22G, 122) of the rolling bearings, wherein the bearing assembly supplies lubricant (G) to the interior of the rolling bearings via lubricant supply paths (52, 152).

[0158] At least one side (22b) of the outer ring is offset towards the axial center side compared to the side (21b) of the inner ring (21) of the rolling bearing.

[0159] An opening (41, 141) is formed on the end face (43, 44, 143) of the outer ring positioning member that abuts against the offset side. The opening allows the outer ring positioning member to pass through radially.

[0160] According to the structure described above [1], the lubricant (G) supplied to the inside of the rolling bearings (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A) is subjected to centrifugal force generated by the rotational force of the inner ring and cage. Through the radially outward-opening portion and opening (41, 141) on the axial back side of the outer rings (22, 22A, 22B, 22C, 22D, 22E, 22F, 22G, 122), a portion of the lubricant (G) that is no longer needed is thrown away to the outer diameter side. As a result, the stirring resistance of the lubricant (G) is reduced, heat generation is suppressed, and a good lubrication condition is maintained. Consequently, the life of the rolling bearings (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A) is extended. In addition, the magnitude of the centrifugal force that throws the lubricant (G) away varies depending on the rotational speed of the rolling bearing (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A), namely the inner ring and cage, so that an appropriate lubricant supply corresponding to the rotational speed can be made.

[0161] [2] According to the bearing assembly described in [1] above (front bearing assembly 10, 10A, 10B, 10C, 10D, 10E, rear bearing assembly 110A), wherein,

[0162] The housing (50, 50A, 50B, 50C) on the radially outer side of the opening (41, 141) is provided with a storage space (51, 151) for storing the lubricant (G) discharged from the interior of the rolling bearing (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A).

[0163] According to the structure described above [2], a portion of the lubricant (G) thrown out radially to the outer side of the rolling bearings (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A) is forcibly and continuously discharged into the storage space (51, 151) and accumulated in the storage space (51, 151) via the radially outward-opening portion and opening (41, 141) on the axial back side of the outer rings (22, 22A, 22B, 22C, 22D, 22E, 22F, 22G, 122).

[0164] [3] A rotating shaft device (200) for a machine tool spindle, wherein...

[0165] The shaft (60) is supported by the bearing devices (front bearing devices 10, 10A, 10B, 10C, 10D, 10E and rear bearing device 110A) described in [1] or [2] above, allowing it to rotate freely.

[0166] According to the structure described above [3], the shaft (60) of the high-speed rotating machine tool spindle can be supported by rolling bearings (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A) that have achieved long service life, making maintenance easier.

[0167] [4] A shaft device for a high-speed electric motor, wherein,

[0168] The shaft is supported by the bearing devices described in [1] or [2] above (front bearing devices 10, 10A, 10B, 10C, 10D, 10E, and rear bearing device 110A) to allow for free rotation.

[0169] According to the structure described above [4], the shaft (60) of the high-speed motor shaft device can be supported by rolling bearings (20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 120A) that have achieved long service life, making maintenance easier.

[0170] Furthermore, this application is based on Japanese Patent Application No. 2023-113273, filed on July 10, 2023, the contents of which are incorporated herein by reference.

[0171] Industrial practicality

[0172] The bearing device according to the present invention can efficiently discharge the lubricant supplied to the bearing, maintain a good lubrication state, stably achieve long-term continuous operation, and extend the bearing's lifespan.

[0173] Furthermore, according to the present invention, the spindle device for machine tool spindles and the spindle device for high-speed motors, the spindle is supported by the aforementioned bearing device to rotate freely, which can reduce the stirring resistance of the lubricant generated by the rotation of the spindle, suppress the rise in bearing temperature and the increase in torque, extend the bearing life, and make maintenance easier.

[0174] Explanation of reference numerals in the attached figures

[0175] 10. Front bearing assembly (bearing assembly)

[0176] 20 Rolling bearings

[0177] 22 Outer ring

[0178] 40 Outer ring spacer (outer ring positioning component)

[0179] 50 Housing

[0180] 40B Outer ring pressing component (outer ring positioning component)

[0181] 52 Lubricant Supply Path

[0182] 60 swivel

[0183] 200 Spindle rotating device for machine tools

[0184] G Lubricant

Claims

1. A bearing device, characterized in that, The device comprises: a housing; a rolling bearing supporting a shaft for rotation relative to the housing; and an outer ring positioning member embedded in the housing to axially position the outer ring of the rolling bearing, the bearing assembly supplying lubricant to the interior of the rolling bearing via a lubricant supply path. At least one side of the outer ring is offset towards the axial center than the side of the inner ring of the rolling bearing. An opening is formed on the end face of the outer ring positioning member that abuts against the offset side, allowing the outer ring positioning member to pass through radially.

2. The bearing device according to claim 1, characterized in that, The housing, located radially outside the opening, is provided with a storage space for storing the lubricant discharged from the interior of the rolling bearing.

3. A rotating shaft device for a machine tool spindle, characterized in that, The rotating shaft of the rotating shaft device is supported by the bearing device as described in claim 1 or 2, allowing it to rotate freely.

4. A shaft device for a high-speed electric motor, characterized in that, The rotating shaft of the rotating shaft device is supported by the bearing device as described in claim 1 or 2, allowing it to rotate freely.

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