Bearing arrangement

Abstract

A bearing device is cooled only by an outer side gap cooling structure for cooling an outer side gap (33). Thus, a temperature difference is generated between an inner side gap (32) and the outer side gap (33). In correspondence with the temperature difference, a relative displacement of an inner ring (37) of the bearing (31) with respect to an outer ring (38) is performed in a direction in which a pre-press of an inside of the bearing (31) is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to a bearing device that rotatably supports a rotating shaft, and particularly to a bearing device that is well suited to support a rotating shaft that is large in diameter and rotates at high speed. BACKGROUND

[0002] In a bearing device that supports a rotating shaft using a bearing, in order to continue smooth rotation support, the pre-pressing inside the bearing is adjusted with high precision.

[0003] However, due to temperature rise of the rotating shaft caused by frictional heat inside the bearing that occurs in conjunction with rotation of the rotating shaft, external factors, and the like, the rotating shaft and the bearing expand in the radial direction (diameter direction), the pre-pressing inside the bearing rises, and as a result, there is a risk that the bearing will lock and no longer be able to rotate smoothly.

[0004] Therefore, in the past, various cooling countermeasures for bearing devices have been proposed.

[0005] For example, the cooling structure of the bearing device disclosed in Japanese Patent Application Publication No. 2019-173911 (Patent Literature) is structured such that an air supply port (23) is provided on the inner peripheral surface of the outer inter-space seat (15) of the rolling bearing (3, 4), compressed air (A) for cooling is blown toward the outer peripheral surface of the inner inter-space seat (16) from this air supply port (23), and each of the outer inter-space seat (15) and the inner inter-space seat (16) is cooled. The compressed air (A) is exhausted from the inter-space (21A, 21B) through an exhaust path (30) formed inside the housing (2).

[0006] Furthermore, the symbols in the above parentheses are symbols attached to the drawings of the patent literature.

[0007] In the bearing device of the past that has the cooling structure, in the process of suppressing temperature rise of the inner ring of the bearing and the rotating shaft by the cooling structure, locking of the bearing can be avoided.

[0008] However, when the temperature rise of these cannot be suppressed by the cooling structure, the bearing locks. For example, in a rotating shaft that is large in diameter and rotates at high speed, the peripheral speed in the outer peripheral surface at the time of high-speed rotation is extremely fast, so the amount of heat generated by the bearing that supports this in rotation is large. Also, the amount of expansion at the time of temperature rise of the rotating shaft that is large in diameter is large. Therefore, in the bearing device of the past that has the cooling structure, there are cases where the pre-pressing inside the bearing cannot be suppressed from changing, leading to locking of the bearing, and an effective countermeasure is desired. Furthermore, not limited to a rotating shaft that is large in diameter, when the pre-pressing inside the bearing cannot be suppressed from changing, because there is a risk that the bearing will lock, an effective countermeasure is similarly needed. SUMMARY

[0009] The present application has been made in view of the above-described circumstances, with an object to provide a bearing device capable of inhibiting an increase in a pre-load in a bearing interior accompanying a temperature rise of a bearing and a rotating shaft.

[0010] To achieve the above object, the bearing device of the present application is characterized by comprising a plurality of bearings rotatably supporting a rotating shaft, an inner spacer disposed between adjacent bearings of the plurality of bearings in contact with inner rings of the adjacent bearings, an outer spacer disposed between the adjacent bearings of the plurality of bearings in contact with outer rings of the adjacent bearings, and an outer spacer cooling structure cooling the outer spacer.

[0011] The bearing device of the above-described structure is capable of inhibiting an increase in a pre-load in a bearing interior accompanying a temperature rise of a bearing and a rotating shaft.

[0012] Specifically, it is preferable that the inner spacer be formed in a cylindrical shape along the inner rings of the bearings, and the outer spacer be formed in a cylindrical shape along the outer rings of the bearings, and that the inner spacer push the inner rings of the bearings in the axial direction relative to the outer rings of the bearings in association with a temperature difference between the inner spacer and the outer spacer.

[0013] The bearing device of the above-described structure is capable of inhibiting an increase in a pre-load in a bearing interior accompanying a temperature rise of a bearing and a rotating shaft.

[0014] Here, it is preferable that the plurality of bearings be arranged in a back surface combination in which back surfaces face each other.

[0015] In the case where the bearings are arranged in a back surface combination, if the inner rings are pushed from the back surface side, the pre-load of the bearings is released. According to the present application, the outer spacer is cooled by the outer spacer cooling structure, a temperature difference is generated between the inner spacer and the outer spacer, and the inner rings of the bearings are pushed in the axial direction from the back surface side by the inner spacer, thereby releasing the pre-load of the bearings. Thus, the inner rings of the bearings are relatively displaced in a direction in which the pre-load in the bearing interior is reduced relative to the outer rings, and an increase in the pre-load in the bearing interior accompanying a temperature rise of the bearing and the rotating shaft is inhibited.

[0016] Further, the present application can be configured as follows: a device main body that houses the plurality of bearings, the inner intermediate space, and the outer intermediate space, a refrigerant flow path for cooling the plurality of bearings formed in the device main body, and a refrigerant flow path that constitutes the outer intermediate space cooling structure formed in the device main body, the refrigerant circulating by connecting the refrigerant flow paths.

[0017] Further, the present application can be configured as follows: a device main body that houses the plurality of bearings, the inner intermediate space, and the outer intermediate space, and that houses a magnetic fluid seal portion, a refrigerant flow path for cooling the magnetic fluid seal portion formed in the device main body, and a refrigerant flow path that constitutes the outer intermediate space cooling structure formed in the device main body, the refrigerant circulating by connecting the refrigerant flow paths.

[0018] Further, the present application can be configured as follows: a device main body that houses the plurality of bearings, the inner intermediate space, and the outer intermediate space, and that houses a heat exhaust portion for cooling the rotating shaft, a refrigerant flow path for cooling the heat exhaust portion formed in the device main body, and a refrigerant flow path that constitutes the outer intermediate space cooling structure formed in the device main body, the refrigerant circulating by connecting the refrigerant flow paths.

[0019] Further, the present application can be configured as follows: a device main body that houses the plurality of bearings, the inner intermediate space, and the outer intermediate space, and that houses a heat exhaust portion for cooling the rotating shaft, a refrigerant flow path for cooling the heat exhaust portion formed in the device main body, and a refrigerant flow path that constitutes the outer intermediate space cooling structure formed in the device main body, the refrigerant circulating by connecting the refrigerant flow paths.

[0020] Thus, by connecting the refrigerant flow paths, a common refrigerant can be circulated through the refrigerant flow paths, and efficient cooling can be achieved.

[0021] As described above, according to the present application, the pre-pressing in the bearing can be inhibited from changing in conjunction with the temperature rise of the bearing and the rotating shaft. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a front cross-sectional view showing the internal structure of the bearing device of the embodiment of the present application.

[0023] Figure 2 is a perspective view showing the internal structure of the bearing device of the embodiment of the present application, with a portion cut away.

[0024] Figure 3is an exploded perspective view showing a part of the internal structure of the bearing device of the embodiment of the present application.

[0025] Figure 4 is an external perspective view of the bearing device of the embodiment of the present application.

[0026] Figure 5A is a front sectional view showing the structure of the bearing portion; Figure 5B and Figure 5C is a front sectional view of a bearing for explaining an example of the pre-press adjusting mechanism.

[0027] Figure 6 is an exploded perspective view showing a part of the external-side- seat cooling structure.

[0028] Figure 7A is a perspective view showing a state in which a plurality of pole pieces are arranged at the outer periphery of the rotating shaft; Figure 7B is a perspective view of a pole piece.

[0029] Figure 8 is a perspective view showing the bearing cooling structure.

[0030] Figure 9 is an exploded perspective view showing a part of the rotating-shaft cooling structure in the heat-removing portion. DETAILED DESCRIPTION

[0031] Hereinafter, the embodiment of the present application will be explained in detail with reference to the drawings.

[0032] Figure 1 is a front sectional view showing the internal structure of the bearing device of the embodiment of the present application, Figure 2 is a perspective view showing a part of this figure, Figure 3 is an exploded perspective view showing a part of this figure, Figure 4 is an external perspective view of this device.

[0033] The bearing device of the embodiment is arranged at the outer periphery of the rotating shaft 10, rotatably supports the rotating shaft 10, and has a function of suppressing the temperature rise of the rotating shaft 10 accompanying rotation.

[0034] As shown in Figure 4 , the bearing device has a cylindrical device main body 20, and this device main body 20 is arranged at the outer periphery of the rotating shaft 10. As shown in Figures 1-3 , the inside of the device main body 20 constitutes each functional portion of the bearing portion 30, the magnetic fluid seal portion 50, and the heat-removing portion 60.

[0035] Figure 5A is a front sectional view showing the structure of the bearing portion.

[0036] The bearing portion 30 is a functional portion for rotatably supporting the rotating shaft 10 by bearings 31.

[0037] As shown in FIG. 1, in the bearing portion 30, a plurality of (two in the figure) bearings 31, inner and outer intermediate seats 32 and 33 disposed between the adjacent bearings 31, an outer ring positioning member 34, an outer ring pressing member 35, and an inner ring pressing member 36 are incorporated. Figure 5A

[0038] If the incorporation steps are described in detail, the incorporation is performed in the order of the outer ring positioning member 34, one of the bearings 31 (lower side in the figure), the inner and outer intermediate seats 32 and 33, and the other of the bearings 31 (upper side in the figure) into the bearing portion 30 formed in the inside of the device main body 20.

[0039] Here, on the outer circumferential surface of the rotating shaft 10, a flange-like inner ring positioning portion 11 protruding in the radial direction is formed, and the inner ring of one of the bearings 31 incorporated into the bearing portion 30 abuts against this inner ring positioning portion 11. In addition, the outer ring of one of the bearings 31 abuts against the outer ring positioning member 34.

[0040] On the outer circumferential surface of the rotating shaft 10, an installation portion (inner ring pressing installation portion 12) of the inner ring pressing member 36 is provided, and the inner ring pressing member 36 is installed in this inner ring pressing installation portion 12. Next, the outer ring pressing member 35 is installed in the entrance of the incorporation portion of the bearing 31 in the device main body 20.

[0041] The inner ring pressing member 36 is a nut structure in which an internal thread is formed on the inner circumferential surface, and is installed in the inner ring pressing installation portion 12 by being screwed into the inner ring pressing installation portion 12 composed of an external thread. In addition, the outer ring pressing member 35 is installed on the device main body 20 using a plurality of screws.

[0042] In this way, each structural element is incorporated into the inside of the device main body 20, and the bearing portion 30 is constructed.

[0043] The bearing 31 is constructed such that an inner ring 37 formed of a ring-like metal member and an outer ring 38 also formed of a ring-like metal member are disposed coaxially, and a rolling element 39 is incorporated between these inner ring 37 and outer ring 38.

[0044] The inner ring 37 is fixed to the rotating shaft 10, and the outer ring 38 is fixed to the device main body 20. The inner ring 37 rotates integrally with the rotating shaft 10, but at this time the rolling element 39 rolls between the outer ring 38 and the inner ring 37.

[0045] ​Further, as the bearing 31, various known bearings such as a ball bearing (for example, a deep groove ball bearing) in which the rolling elements 39 are constituted by balls of metal, ceramic, or the like, a roller bearing (for example, a tapered roller bearing) in which the rolling elements 39 are constituted by rollers of metal, or the like can be used. In the present embodiment, an angular contact ball bearing that supports a radial load acting in the radial direction and an axial load acting in the axial direction is used as the bearing 31.

[0046] The inner side spacers 32 are arranged between the respective bearings 31 in a state of abutting against the respective inner rings 37, and function as spacers that adjust the arrangement intervals of the inner rings 37 of the respective bearings 31. Further, the outer side spacers 33 are arranged between the respective bearings 31 in a state of abutting against the respective outer rings 38, and function as spacers that adjust the arrangement intervals of the outer rings 38 of the respective bearings 31.

[0047] The inner ring 37 of each bearing 31 is defined in a fixed position in the axial direction by the inner ring positioning portion 11, the inner side spacer 32, and the inner ring pressing member 36. Further, the outer ring 38 of each bearing 31 is defined in a fixed position in the axial direction by the outer ring positioning member 34, the outer side spacer 33, and the outer ring pressing member 35.

[0048] Further, with respect to the outer ring 38, the outer ring positioning member 34, the outer side spacer 33, and the outer ring pressing member 35 of each bearing 31 that are fixed to the device main body 20, the inner ring 37, the inner ring positioning portion 11, the inner side spacer 32, and the inner ring pressing member 36 of each bearing 31 rotate integrally with the rotating shaft 10.

[0049] The bearing 31 adjusts the internal pre-pressing (that is, the pressure received by the rolling elements 39 from the inner ring 37 and the outer ring 38) when the bearing 31 is incorporated into the bearing portion 30 of the device main body 20.

[0050] In order to perform this pre-pressing adjustment, the inner ring 37 and the outer ring 38 of the bearing 31 are configured to be combined in a manner that allows relative displacement in the axial direction, and by adjusting the relative positions thereof, the internal pre-pressing of the bearing 31 (hereinafter, also omitted as "the pre-pressing of the bearing 31") can be increased or decreased.

[0051] For example, in the bearing 31 shown in FIG. 8, as shown enlarged in FIG. 9, a slope 38a is formed on the inner peripheral surface of the outer ring 38. Further, FIG. 10 is an enlarged view of the bearing 31 arranged at the lower right in FIG. 8. Further, as shown in FIG. 11, the inner ring 37 and the outer ring 38 of the bearing 31 are configured to be combined in a manner that allows relative displacement in the axial direction. Figure 5A Figure 5B Figure 5C Figure 5B Figure 5C Figure 5A Figure 5B ​​​​​​As shown, if the inner ring 37 is relatively displaced in the direction of the arrow A with respect to the outer ring 38, the pressure acting on the rolling elements 39 sandwiched between these inner ring 37 and outer ring 38 decreases because the inner ring 37 is relatively displaced in the direction in which the slope 38a formed on the inner peripheral surface of the outer ring 38 widens.

[0052] On the contrary, as shown in FIG. 6, if the inner ring 37 is relatively displaced in the direction of the arrow B with respect to the outer ring 38, the pressure acting on the rolling elements 39 sandwiched between these inner ring 37 and outer ring 38 increases because the inner ring 37 is relatively displaced in the direction in which the slope 38a formed on the inner peripheral surface of the outer ring 38 narrows. Figure 5C

[0053] Generally, the pre-pressing of the bearing 31 is adjusted to be the desired pressure by the dimensional difference of the length of the inner spacer 32 and the length of the outer spacer 33 that defines the relative positions of the outer ring 38 and the inner ring 37.

[0054] However, there are cases in which the temperature of the bearing 31 and the rotating shaft 10 rises accompanying the rotation of the rotating shaft 10, the bearing 31 and the rotating shaft 10 expand in the radial direction (diameter direction), and the pre-pressing of the bearing 31 rises. Moreover, there is a risk that the bearing 31 locks because of this pre-pressing rise, and the smooth rotation of the rotating shaft 10 is hindered.

[0055] Therefore, the bearing device of the present embodiment has a function of suppressing the change in the pre-pressing of the bearing 31 accompanying the temperature rise of the bearing 31 and the rotating shaft 10.

[0056] The bearing device of the present embodiment has an outer spacer cooling structure and a pre-pressing adjustment mechanism in order to suppress the change in the pre-pressing of the bearing 31.

[0057] The outer spacer cooling structure has a function of cooling the outer spacer 33, actively setting a temperature difference between the inner spacer 32 and the outer spacer 33, and cooling the bearing 31 and the rotating shaft 10 by absorbing the heat transmitted from the bearing 31.

[0058] That is, heat is generated in the bearing 31 by the friction between the rolling elements 39 and the inner ring 37 and the outer ring 38 accompanying the rotation of the rotating shaft 10, and this heat is transmitted to the inner spacer 32 and the outer spacer 33. In addition, the rotating shaft 10 also has heat due to external factors and the like, and this heat is transmitted to the inner spacer 32 and also to the outer spacer 33 via the bearing 31. In this way, the temperatures of the inner spacer 32 and the outer spacer 33 rise.

[0059] ​In such a situation, if only the outer inter-land 33 is cooled, a large temperature difference is generated between the inner inter-land 32 and the outer inter-land 33. On this basis, the bearing 31 and the rotating shaft 10 are cooled by absorbing heat from the bearing 31 and the rotating shaft 10 through the outer inter-land 33.

[0060] In the bearing device of the present embodiment, the outer inter-land cooling structure is configured as follows.

[0061] As shown in Figure 6 , a groove 33a extending in the circumferential direction is formed on the outer peripheral surface of the outer inter-land 33. In a state in which the outer inter-land 33 is fitted inside the device main body 20, the outer peripheral surface of the outer inter-land 33 is in close contact with the inner peripheral surface of the device main body 20, and a hollow portion (see Figure 1 , Figure 2 and Figure 5A ) is formed by the groove 33a. The hollow portion formed by the groove 33a constitutes a refrigerant flow path for circulating refrigerant.

[0062] As shown in Figure 1 and Figure 6 , through holes 21a and 21b are formed in two positions of the device main body 20, which lead from the outer peripheral surface to the inner peripheral surface. These through holes 21a and 21b are both open to the hollow portion formed by the groove 33a. Moreover, refrigerant is supplied from one of the through holes 21a into the hollow portion formed by the groove 33a, and the refrigerant flows in the hollow portion formed by the groove 33a and is discharged from the other of the through holes 21b.

[0063] The refrigerant flowing in the hollow portion formed by the groove 33a gradually absorbs heat from the outer inter-land 33. As a result, the outer inter-land 33 is cooled, and the temperature rise is suppressed.

[0064] In addition, in the bearing device of the present embodiment, the outer inter-land 33, the inner inter-land 32, the inner ring 37 of the bearing 31, the rolling elements 39, and the outer ring 38 shown in Figure 5A are used, and the pre-press adjustment mechanism is configured as follows.

[0065] That is, if the outer inter-land 33 is cooled by the outer inter-land cooling structure, and a large temperature difference is generated between the inner inter-land 32 and the outer inter-land 33, the expansion of the outer inter-land 33 is suppressed, but the inner inter-land 32 thermally expands in the axial direction. Therefore, the inner ring 37 of the bearing 31 abutting against the inner inter-land 32 is pushed by the inner inter-land 32. That is, the inner inter-land 32 constitutes a pushing mechanism that pushes the inner ring 37 of the bearing 31 in the axial direction.

[0066] In this way, the inner ring 37 of the bearing 31 is pushed by the inner inter-land 32, and a relative displacement is generated between the inner ring 37 and the outer ring 38 of the bearing 31.

[0067] Here, the plurality of bearings 31 incorporated in the device main body 20 are made into a so-called "back surface combination" in which the back surfaces 31a are arranged facing each other, and are configured so as to arrange the inner side spacer 32 and the outer side spacer 33 between the bearings 31. Thus, when the inner ring 37 is fastened from the front surface 31b side while the plurality of bearings 31 are arranged in the back surface combination, the pre-press of the bearings 31 becomes high, and on the other hand, if the inner ring 37 is pushed from the back surface 31a side, the pre-press of the bearings 31 is released.

[0068] That is, if pushed by the inner side spacer 32 arranged in the middle portion of the plurality of bearings 31, as shown in Figure 5B the inner ring 37 is pushed in the direction of the arrow A, and the inner ring 37 is displaced relative to the outer ring 38. Also, since the inner peripheral surface of the outer ring 38 is formed with a slope 38a that widens toward the direction of this arrow A, the pressure acting on the rolling body 39 sandwiched between these inner ring 37 and outer ring 38 decreases (that is, the pre-press of the bearing 31 decreases).

[0069] On the other hand, as has been described, along with the temperature rise of the bearings 31, the rotating shaft 10, the bearings 31 and the rotating shaft 10 expand in the radial direction (diameter direction), and the pre-press of the bearings 31 rises.

[0070] The pre-press adjustment mechanism, with respect to the rise in the pre-press of the bearings 31 that accompanies the temperature rise of the bearings 31, the rotating shaft 10, causes a large temperature difference between the outer side spacer 33 and the inner side spacer 32, as described above, and decreases the pre-press of the bearings 31. Thus, with respect to the rise in the pre-press of the bearings 31 that accompanies the temperature rise of the bearings 31, the rotating shaft 10, the pre-press of the bearings 31 is decreased to cancel it out, as a result, the change in the pre-press of the bearings 31 is suppressed. Also, by suppressing the change in the pre-press of the bearings 31, locking of the bearings 31 can be avoided, and a rotation support that maintains smooth rotation of the rotating shaft 10 can be achieved.

[0071] Next, the magnetic fluid seal portion 50 provided inside the device main body 20 will be described.

[0072] Returning Figures 1-3 to the inside of the device main body 20, the magnetic fluid seal portion 50 is provided in parallel with the bearing portion 30. The magnetic fluid seal portion 50 is a functional portion for sealing a gap at the outer periphery of the rotating shaft 10 by filling the gap with a magnetic fluid and holding the magnetic fluid by magnetic lines of force.

[0073] In the magnetic fluid seal portion 50, a magnetic pole piece called a pole piece 51, a magnet 52, and a magnetic fluid 53 are incorporated. The pole piece 51, as shown in Figure 7A is formed in a circular ring shape from a magnetic material with a high magnetic permeability, and as shown in Figure 7BAs shown, the plurality of (three in the figure) pole pieces 51 are arranged in parallel in the axial direction and are fitted into the magnetic fluid seal portion 50 (see FIG. 6) formed in the interior of the device main body 20 in a state in which the pole pieces 51 are arranged in parallel with the magnetic fluid seal portion 50. Figures 1-3 The magnets 52 are fitted in parallel to the side of the pole pieces 51, and the magnetic fluid 53 is filled in the gap between the inner peripheral surface of the pole pieces 51 and the outer peripheral surface of the rotating shaft 10. Furthermore, the magnetic lines of force formed by the magnets 52 hold the magnetic fluid 53 in the gap.

[0074] This magnetic fluid seal portion 50 also generates frictional heat between the magnetic fluid 53 and the rotating shaft 10 in conjunction with the rotation of the rotating shaft 10, and the temperature rises. Furthermore, since the frictional heat of the magnetic fluid 53 is transmitted to the rotating shaft 10, the rotating shaft 10 expands in the radial direction, so the gap between the rotating shaft 10 and the pole pieces 51 narrows, and there is a risk of impeding the smooth rotation of the rotating shaft 10.

[0075] Therefore, in the bearing device of the present embodiment, a cooling configuration (magnetic fluid seal portion cooling configuration) for cooling the magnetic fluid seal portion 50 is constituted. The heat generated in the magnetic fluid 53 is transmitted to the pole pieces 51, but the magnetic fluid seal portion cooling configuration is constituted in such a manner that the refrigerant absorbs the heat transmitted to the pole pieces 51 and performs cooling of the magnetic fluid 53.

[0076] That is, as shown in FIGS. 5 and 6, a recess 51a extending in the circumferential direction is formed on the outer peripheral surface of the pole piece 51, and in a state in which the pole piece 51 is fitted into the interior of the device main body 20, the outer peripheral surface of the pole piece 51 is in close contact with the inner peripheral surface of the device main body 20, and a hollow portion (see FIGS. 6 and 7) resulting from the recess 51a is formed. Figure 7A Figure 7B That is, as shown in FIGS. 5 and 6, a recess 51a extending in the circumferential direction is formed on the outer peripheral surface of the pole piece 51, and in a state in which the pole piece 51 is fitted into the interior of the device main body 20, the outer peripheral surface of the pole piece 51 is in close contact with the inner peripheral surface of the device main body 20, and a hollow portion (see FIGS. 6 and 7) resulting from the recess 51a is formed. Figure 1 Figure 2 Therefore, in the bearing device of the present embodiment, a cooling configuration (magnetic fluid seal portion cooling configuration) for cooling the magnetic fluid seal portion 50 is constituted. The heat generated in the magnetic fluid 53 is transmitted to the pole pieces 51, but the magnetic fluid seal portion cooling configuration is constituted in such a manner that the refrigerant absorbs the heat transmitted to the pole pieces 51 and performs cooling of the magnetic fluid 53.

[0077] As shown in FIGS. 5 and 6, a plurality of (six in the figure) through holes 22a, 22b, 22c, 22d, 22e, 22f are formed in the device main body 20, which lead from the outer peripheral surface to the inner peripheral surface, and these through holes 22a, 22b, 22c, 22d, 22e, 22f are all open to the hollow portion resulting from the recess 51a (see FIGS. 6 and 7). Figure 4 Figure 1 As shown in FIGS. 5 and 6, the recess 51a formed on the outer peripheral surface of each pole piece 51 is blocked in part in the circumferential direction by a partition wall 51b, and with the partition wall 51b as a boundary, half of the through holes 22a, 22b, 22c are open on one side thereof, and the remaining half of the through holes 22d, 22e, 22f are open on the other side thereof. Figure 7A Figure 7B

[0078] ​​​​​Further, although not shown in the drawings, Figure 4 The through holes 22d and 22e, 22b and 22c are respectively connected by pipes, and the hollow portions produced by the grooves 51a formed on the outer peripheral surfaces of the respective pole pieces 51 constitute a continuous refrigerant flow path via the pipes.

[0079] Specifically, Figure 4 The through hole 22a shown in the drawing serves as an inlet for refrigerant, and if refrigerant is supplied from here, Figure 7A The groove 51a of the first pole piece 51 shown in the drawing takes in refrigerant, and the refrigerant flows in the hollow portion produced by the groove 51a. Next, the refrigerant is supplied from the other through hole 22d (refer to Figure 4 ) opening into the groove 51a via a pipe to the adjacent through hole 22e, Figure 7A The groove 51a of the second pole piece 51 shown in the drawing takes in refrigerant, and the refrigerant flows in the hollow portion produced by the groove 51a. Next, the refrigerant is supplied from the other through hole 22b (refer to Figure 4 ) opening into the groove 51a via a pipe to the adjacent through hole 22c, Figure 7A The groove 51a of the third pole piece 51 shown in the drawing takes in refrigerant, and the refrigerant flows in the hollow portion produced by the groove 51a. Then, the refrigerant is discharged from the through hole 22f (refer to Figure 4 ).

[0080] In the process of the refrigerant flowing in the refrigerant flow path via such a path, the refrigerant absorbs the heat of the pole pieces 51, and cools the magnetic fluid 53.

[0081] Next, the bearing cooling structure provided on the device main body 20 will be described.

[0082] Returning to Figures 1-3 , a groove 20a is formed on the outer peripheral surface of the device main body 20. This groove 20a, as shown in Figure 8 , is formed on the outer peripheral surface of the device main body 20 in a manner so as to trace one helical track. On the outer peripheral surface of the device main body 20 on which the groove 20a is formed, as shown in Figures 1-3 , a cylindrical covering member 23 is fitted, and the inner peripheral surface of this covering member 23 is in close contact with the outer peripheral surface of the device main body 20, and forms a hollow portion produced by the groove 20a extending helically. The hollow portion produced by the groove 20a constitutes a refrigerant flow path for circulating refrigerant.

[0083] As shown in Figure 2 and Figure 3As shown, two through-holes 23a, 23b are formed in the cover member 23 from the outer peripheral surface to the inner peripheral surface, one of the through-holes 23a is opened in the vicinity of the start end portion of the spiral hollow portion produced by the groove 20a, and the other through-hole 23b is opened in the vicinity of the end end portion of the spiral hollow portion produced by the groove 20a.

[0084] Further, the one through-hole 23a opened in the vicinity of the start end portion of the hollow portion is communicated with the through-hole 22f of the magnetic fluid seal portion 50 described above by a pipe not shown (see Figure 4 ). Thus, the refrigerant discharged from the through-hole 22f flows in the refrigerant flow path of the seal portion cooling structure, and is supplied from the through-hole 23a to the hollow portion produced by the groove 20a via the pipe.

[0085] Further, the refrigerant supplied from the through-hole 23a flows in the spiral hollow portion produced by the groove 20a, and is discharged from the other through-hole 23b (see Figure 4 ).

[0086] The refrigerant flowing in the spiral hollow portion produced by the groove 20a gradually absorbs heat from the device main body 20. Thus, the plurality of bearings 31 housed in the device main body 20 are cooled.

[0087] Further, with reference to Figure 1 and Figure 6 , the two through-holes 21a, 21b opened in the hollow portion produced by the groove 33a of the outer intermediate seat 33 described above are also opened in the spiral hollow portions produced by the grooves 20a, respectively, a portion of the refrigerant flowing in the spiral hollow portions is supplied from the one through-hole 21a to the hollow portion produced by the groove 33a of the outer intermediate seat 33, flows in the hollow portion, and is returned to the spiral hollow portion from the other through-hole 21b.

[0088] Figure 6 The through-holes 21a, 21b shown are provided at positions which are point-symmetrical with respect to the center axis (positions rotated by 180 degrees). Further, the refrigerant supplied from the one through-hole 21a is branched to flow in the right direction and in the left direction in the groove 33a, is discharged from the other through-hole 21b, and is returned to the spiral hollow portion produced by the groove 33a.

[0089] Further, a structure can also be made in which the through-holes 21a, 21b are provided in parallel with the partition wall sandwiched therebetween in the vicinity of the circumferential direction, and the refrigerant supplied from the one through-hole 21a flows in one direction in the groove 33a, and is discharged from the other through-hole 21b. If such a structure is made, the collision of the refrigerant produced by the confluence in the through-hole 21b can be eliminated, and the refrigerant can be smoothly discharged.

[0090] Next, the heat discharge portion 60 provided inside the device main body 20 will be described.

[0091] Returning to Figures 1-3 , inside the device main body 20, the heat discharge portion 60 is provided in parallel with the bearing portion 30 on the opposite side of the magnetic fluid seal portion 50. The heat discharge portion 60 is a functional portion for absorbing heat accumulated in the rotary shaft 10 to directly cool the rotary shaft 10. In the heat discharge portion 60, a configuration for cooling the rotary shaft 10 is formed.

[0092] That is, as shown in Figure 9 , the annular shaft heat absorbing member 61 is fitted in the heat discharge portion 60 of the device main body 20. The inner peripheral surface of the shaft heat absorbing member 61 is arranged on the outer peripheral surface of the rotary shaft 10 and is in slight contact therewith. Thus, heat from the rotary shaft 10 is transferred to the shaft heat absorbing member 61.

[0093] On the outer peripheral surface of the shaft heat absorbing member 61, a groove 61a extending in the circumferential direction is formed. In a state in which the shaft heat absorbing member 61 is fitted inside the device main body 20, the outer peripheral surface of the shaft heat absorbing member 61 is in close contact with the inner peripheral surface of the device main body 20, and a hollow portion (see Figure 1 , Figure 2 and Figure 9 ) is formed by the groove 61a. The hollow portion formed by the groove 61a constitutes a refrigerant flow path for circulating refrigerant.

[0094] In two portions of the device main body 20, through holes 24a, 24b are formed that open from the outer peripheral surface to the inner peripheral surface. These through holes 24a, 24b are both open to the hollow portion formed by the groove 61a. One of the through holes 24a is in communication with the through hole 23b formed in the cover member 23 of the bearing cooling configuration via an unillustrated pipe. Thus, refrigerant discharged from the through hole 23b in the bearing cooling configuration is delivered to the one through hole 24a via the unillustrated pipe (see Figure 4 ).

[0095] Further, refrigerant is supplied from this through hole 24a into the hollow portion formed by the groove 61a, and the refrigerant flows in the hollow portion formed by the groove 61a and is discharged from the other through hole 24b.

[0096] The refrigerant flowing in the hollow portion formed by the groove 61a gradually absorbs heat transferred from the rotary shaft 10 to the shaft heat absorbing member 61. Thus, the rotary shaft 10 is cooled.

[0097] Here, Figure 9 , the through holes 24a, 24b are also in communication with Figure 6The through holes 21a, 21b shown are also provided at positions that are point-symmetrical about the center axis (positions that are turned through 180 degrees), respectively. Moreover, the refrigerant supplied from one of the through holes 24a is branched to flow in the right direction and in the left direction in the groove 61a, and is discharged from the other of the through holes 24b.

[0098] Furthermore, the structure can also be such that the through holes 24a, 24b are provided in parallel at positions near each other in the circumferential direction with the partition wall interposed therebetween, and the refrigerant supplied from one of the through holes 24a flows in one direction in the groove 61a and is discharged from the other of the through holes 24b. If so configured, the collision of the refrigerant due to the confluence thereof in the through hole 24b can be eliminated, and the refrigerant can be smoothly discharged.

[0099] As shown in Figure 9 the other of the through holes 24b formed in the device main body 20 is connected via a pipe not shown to a refrigerant cooling circulation device (not shown) provided on the bearing device at the same time. The refrigerant discharged from the other of the through holes 24b is delivered to the refrigerant cooling circulation device not shown, and is cooled in the device, and is supplied again to the through hole 22a of the seal portion cooling structure in a circulating manner.

[0100] Here, the refrigerant cooling circulation device not shown will be described with reference to Figure 4 If the circulation path of the refrigerant is described again, the refrigerant supplied from the refrigerant cooling circulation device not shown to the through hole 22a of the seal portion cooling structure flows in the hollow portion produced by the groove 51a formed in the seal portion cooling structure, and absorbs the heat transmitted from the rotating shaft 10 to the pole piece 51. Figure 1 Figure 2 As shown in

[0101] Next, the refrigerant is supplied from the through hole 22f of the seal portion cooling structure to the through hole 23a of the bearing cooling structure, and flows in the spiral-shaped hollow portion produced by the groove 20a formed in the bearing cooling structure, and absorbs the heat transmitted from the rotating shaft 10 to the device main body 20.

[0102] Furthermore, a part of the refrigerant is also supplied from the through hole 21a formed in the device main body 20 to the hollow portion produced by the groove 33a formed in the outer intermediate seat cooling structure, and flows in the hollow portion, and absorbs the heat transmitted from the bearing 31 and the rotating shaft 10 to the outer intermediate seat 33. Moreover, the refrigerant is returned from the other of the through holes 21b formed in the device main body 20 to the spiral-shaped hollow portion produced by the groove 20a formed in the bearing cooling structure.

[0103] ​Next, the refrigerant supplied from the through-hole 23b of the bearing cooling structure to the through-hole 24a of the heat discharge portion 60 flows in the hollow portion formed in the heat discharge portion 60 by the groove 61a, and absorbs heat transmitted from the rotating shaft 10 to the shaft heat absorbing member 61. Then, the refrigerant returns to the refrigerant cooling circulation device not shown from the through-hole 24b of the heat discharge portion 60, is cooled, and is supplied again to the through-hole 22a of the seal portion cooling structure.

[0104] The bearing device of the present embodiment, as described above, has each of the bearing cooling structure, the magnetic fluid seal portion cooling structure, the cooling structure of the rotating shaft 10 in the heat discharge portion 60, and the outer side gap cooling structure, so heat from the bearing 31 and the rotating shaft 10 is absorbed by the refrigerant circulated in each of the cooling structures, and the bearing 31 and the rotating shaft 10 can be effectively cooled.

[0105] Further, since the common refrigerant is caused to flow in the refrigerant flow paths provided in each of the cooling structures in communication, the circulation control of the refrigerant can be simplified, and further effective cooling can be achieved.

[0106] Further, the present application is not limited to the above-described embodiments, and various modifications and applications can be made as appropriate.

[0107] For example, the pre-load adjustment mechanism for reducing the pre-load inside the bearing is not limited to Figure 5B and Figure 5C the structure using the slope 38a as described above, various structures that reduce the pre-load inside the bearing in conjunction with the relative displacement of the outer ring and the inner ring of the bearing can be used.

[0108] In the above-described embodiments, the groove 20a is formed on the outer peripheral surface of the device main body 20 in order to form the refrigerant flow path of the bearing cooling structure, but a groove can be formed on the cover member 23 as the refrigerant flow path, and grooves can be formed on both the outer peripheral surface of the device main body 20 and the cover member 23 to constitute the refrigerant flow path.

[0109] Similarly, instead of the groove 33a of the outer side gap cooling structure that forms the refrigerant flow path, a groove can be formed on the inner peripheral surface of the device main body 20 that contacts the outer side gap 33 as the refrigerant flow path, and grooves can be formed on both the outer side gap 33 and the inner peripheral surface of the device main body 20 to constitute the refrigerant flow path.

[0110] Similarly, instead of the groove 51a of the magnetic fluid seal portion cooling structure that forms the refrigerant flow path, a groove can be formed on the inner peripheral surface of the device main body 20 that contacts the pole piece 51 as the refrigerant flow path, and grooves can be formed on both the pole piece 51 and the inner peripheral surface of the device main body 20 to constitute the refrigerant flow path.

[0111] Also, instead of the recess 61a of the heat exhaust portion 60 that forms the refrigerant flow path, a recess can be formed on the inner circumferential surface of the device main body 20 that contacts the shaft heat absorbing member 61 as the refrigerant flow path, and a recess can be formed on both the shaft heat absorbing member 61 and the inner circumferential surface of the device main body 20 to constitute the refrigerant flow path.

[0112] Further, in the above-described embodiment, the configuration of cooling the bearing 31, the configuration of cooling the magnetic fluid seal portion 50, and the configuration of cooling the rotating shaft 10 in the heat exhaust portion 60 are provided on the basis of the configuration of cooling the outer intermediate seat 33, but a part of them can be omitted.

[0113] Further, in the above-described embodiment, the refrigerant is supplied from the magnetic fluid seal portion 50 to the outer intermediate seat 33 via the periphery of the device main body 20, and further flows from the periphery of the device main body 20 to the heat exhaust portion 60, but the flow path of the refrigerant is not limited thereto, and can be appropriately changed as necessary.

Claims

1. A bearing assembly comprising a plurality of bearings that rotatably support a rotating shaft, characterized in that, It features an inner inter-seat, an outer inter-seat, and an outer inter-seat cooling structure. The inner spacer is positioned between the adjacent bearings in such a way that it contacts the inner rings of each of the aforementioned bearings. The outer spacer is positioned between the adjacent bearings in such a way that it contacts the outer rings of each of the aforementioned bearings. The outer interspindle cooling structure cools the aforementioned outer interspindle. The bearing assembly comprises a main body that houses the aforementioned multiple bearings, inner spacer, and outer spacer. A refrigerant flow path for cooling the aforementioned multiple bearings is formed on the main body of the device, and A refrigerant flow path constituting the aforementioned outer interseat cooling structure is formed on the main body of the device. By connecting these refrigerant flow paths, the refrigerant can be circulated. The refrigerant flow path for cooling the aforementioned bearings has a spiral hollow portion formed by grooves formed on the main body of the device. The refrigerant flow path for cooling the outer spacer has a hollow portion created by grooves formed on the outer spacer. A portion of the refrigerant flowing in the spiral hollow portion formed by the groove formed on the main body of the device is supplied to the hollow portion formed by the groove formed on the outer side seat.

2. The bearing device according to claim 1, characterized in that, The structure was made as follows: The main body of the device comprises a plurality of bearings, an inner spacer and an outer spacer, and a magnetic fluid sealing part therein. A refrigerant flow path for cooling the magnetic fluid seal is formed on the main body of the aforementioned device, and A refrigerant flow path constituting the aforementioned outer interseat cooling structure is formed on the main body of the device. These refrigerant flow paths are connected to allow the refrigerant to circulate.

3. The bearing device according to claim 1, characterized in that, The structure was made as follows: The main body of the device comprises a plurality of bearings, an inner spacer, and an outer spacer, and houses a heat dissipation section for cooling the rotating shaft. A refrigerant flow path for cooling the heat dissipation section is formed on the main body of the aforementioned device, and A refrigerant flow path constituting the aforementioned outer interseat cooling structure is formed on the main body of the device. These refrigerant flow paths are connected to allow the refrigerant to circulate.

4. The bearing device according to claim 1, characterized in that, The structure was made as follows: The main body of the device comprises a plurality of bearings, an inner spacer and an outer spacer, and houses a magnetic fluid seal and a heat dissipation section for cooling the rotating shaft. The main body of the device has a refrigerant flow path for cooling the multiple bearings, a refrigerant flow path for cooling the magnetic fluid seal, a refrigerant flow path for cooling the heat dissipation part, and a refrigerant flow path constituting the outer side seat cooling structure. These refrigerant flow paths are connected to circulate the refrigerant.

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