Spindle Unit

Abstract

To provide a spindle device capable of suppressing increase of a dimension of an outer diameter in forming a flow passage through which a cooling liquid flows.SOLUTION: A spindle device includes: a rotating shaft; a cylindrical bearing housing extending in a direction of a central axis of the rotating shaft; a bearing mounted on an inner peripheral surface of the bearing housing and rotatably supporting the rotating shaft; and a first elastic member. Inside of the bearing housing, a first flow passage and a second flow passage extending in the direction of the central axis of the bearing housing are formed. On an outer peripheral surface of the bearing housing, a first groove is formed which extends in a circumferential direction of the bearing housing and is connected to the first flow passage and the second flow passage. The first elastic member closes an opening of the first groove.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a spindle device. [Background technology]

[0002] Patent Document 1 (JP 2014-52081 A) describes a bearing device. The bearing device described in Patent Document 1 has a rotating shaft, a housing, a bearing, and a cooling jacket. The housing has a cylindrical shape extending in the direction of the central axis of the rotating shaft. The bearing is attached to the inner peripheral surface of the housing. The bearing rotatably supports the rotating shaft. A cooling oil groove is formed in the outer peripheral surface of the housing. The cooling jacket is attached to the outer peripheral surface of the housing so as to cover the cooling oil groove. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-52081 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the bearing device described in Patent Document 1, the rotation of the rotating shaft generates heat around the rotating shaft. This heat can cause the dimensions of the various components around the rotating shaft to change. In the bearing device described in Patent Document 1, the housing is cooled by cooling oil flowing through a flow path defined by a cooling oil groove and a cooling jacket, so the above-mentioned dimensional change is suppressed. However, in the bearing device described in Patent Document 1, the flow path is defined by attaching a cooling jacket to the outer peripheral surface of the housing, which increases the outer diameter.

[0005] The present invention has been made in view of the problems of the prior art as described above. More specifically, the present invention provides a spindle device capable of suppressing an increase in the outer diameter dimension in order to form a flow path through which a coolant flows.

Means for Solving the Problems

[0006] The spindle device of the present invention includes a rotating shaft, a cylindrical bearing housing extending in the direction of the central axis of the rotating shaft, a bearing attached to the inner peripheral surface of the bearing housing and rotatably supporting the rotating shaft, and a first elastic member. Inside the bearing housing, a first flow path and a second flow path extending in the direction of the central axis of the bearing housing are formed. On the outer peripheral surface of the bearing housing, a first groove extending in the circumferential direction of the bearing housing and connected to the first flow path and the second flow path is formed. The first elastic member closes the opening of the first groove.

[0007] The above spindle device may further include a first cover attached to the outer peripheral surface of the bearing housing so as to cover the first elastic member.

[0008] In the above spindle device, a partition may be arranged between a portion of the first groove connected to the first flow path and a portion of the first groove connected to the second flow path.

[0009] In the above spindle device, the first flow path and the second flow path may be at different positions in the circumferential direction of the bearing housing.

[0010] The above spindle device may further include a second elastic member. On the outer peripheral surface of the bearing housing, a second groove extending in the circumferential direction of the bearing housing, connected to the first flow path and the second flow path, and spaced apart from the first groove in the direction of the central axis of the bearing housing may be formed. The second elastic member may close the opening of the second groove.

[0011] The spindle device may further include a cylindrical motor housing extending in the direction of the central axis of the bearing housing, a motor, and a second cover. The motor may have a stator attached to the inner peripheral surface of the motor housing, and a rotor attached to the rotating shaft so as to face the stator in the radial direction of the motor housing. At least one or more third grooves may be formed in the outer peripheral surface of the motor housing, extending in the circumferential direction of the motor housing and fluidly connected to the second flow path. The second cover may be disposed on the motor housing so as to cover the at least one or more grooves. housing The outer circumferential surface of the

[0012] In the spindle device, the at least one third groove may be a plurality of circumferential grooves spaced apart from one another in the direction of the central axis of the rotating shaft. Two of the plurality of circumferential grooves adjacent to one another in the direction of the central axis of the rotating shaft may be connected to one another.

[0013] In the above spindle device, the bearing may be a hydrostatic bearing that supports a load from the rotating shaft in the direction of the central axis of the rotating shaft and in a direction perpendicular to the central axis of the rotating shaft. Effect of the Invention

[0014] According to the spindle device of the present invention, it is possible to suppress an increase in the outer diameter dimension of the housing due to the formation of a flow passage for the coolant. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a first cross-sectional view of the spindle device 100. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 2 is an enlarged view of IV in FIG. [Diagram 5] 2 is a second cross-sectional view of the spindle device 100. FIG. [Figure 6] FIG. 2 is a first perspective view of a motor housing 60. [Figure 7] 7 is a second perspective view of the motor housing 60 as viewed from a direction VII in FIG. 6. [Figure 8] FIG. 1 is a first cross-sectional view of a spindle device 100 according to a first modified example. [Figure 9] FIG. 11 is a second cross-sectional view of the spindle device 100 according to the second modified example. [Figure 10] FIG. 13 is a perspective view of a spindle device 100 according to a fourth modified example. [Figure 11] FIG. 13 is a perspective view of a spindle device 100 according to a fifth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described with reference to the accompanying drawings. In the following drawings, the same or corresponding parts are designated by the same reference numerals, and redundant description will not be repeated.

[0017] (Configuration of spindle device according to embodiment) The configuration of a spindle device according to an embodiment (hereinafter referred to as "spindle device 100") will be described.

[0018] FIG. 1 is a first cross-sectional view of the spindle device 100. FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. In FIGS. 2 and 3, illustrations other than the bearing housing 20 are omitted. FIG. 4 is an enlarged view of line IV in FIG. 1. FIG. 5 is a second cross-sectional view of the spindle device 100. As shown in FIGS. 1 to 5, the spindle device 100 has a rotating shaft 10, a bearing housing 20, elastic members 30a and 30b, a cover 40, a bearing sleeve 50, a motor housing 60, a cover 70, a motor 80, and a cover 90.

[0019] The central axis of the rotating shaft 10 is defined as the central axis A. The rotating shaft 10 has a first end 10a and a second end 10b in the direction of the central axis A. The second end 10b is the end opposite the first end 10a. The rotating shaft 10 has an expanded diameter portion 11 and an expanded diameter portion 12. The expanded diameter portion 11 is located at the first end 10a, and the expanded diameter portion 12 is located between the first end 10a and the second end 10b. The portion of the rotating shaft 10 between the expanded diameter portion 11 and the expanded diameter portion 12 is defined as the first portion 13, and the portion of the rotating shaft 10 located closer to the second end 10b than the expanded diameter portion 12 is defined as the second portion 14.

[0020] The outer diameter of the rotating shaft 10 at the expanded diameter portion 11 and the outer diameter of the expanded diameter portion 12 at the expanded diameter portion 12 are larger than the outer diameter of the rotating shaft 10 at the first portion 13. Rotation axis 10 The outer diameter of the first portion 13 is larger than the outer diameter of the rotating shaft 10 at the second portion 14. The expanded diameter portions 11 and 12 protrude from the first portion 13 and the second portion 14 in a direction perpendicular to the central axis A. The expanded diameter portions 11 and 12, the first portion 13 and the second portion 14 each have a circular shape in a cross-sectional view perpendicular to the central axis A.

[0021] The bearing housing 20 has a cylindrical shape extending in the direction of the central axis A. In a cross-sectional view perpendicular to the central axis A, the bearing housing 20 has a circular ring shape. The bearing housing 20 has an inner circumferential surface 20a and an outer circumferential surface 20b. A flow path 21, a flow path 22, and a supply port 23 are formed inside the bearing housing 20. The flow path 21 and the flow path 22 extend in the direction of the central axis A. The supply port 23 is connected to the flow path 21 at one end and to the outside of the bearing housing 20 at the other end.

[0022] The flow passage 21 and the flow passage 22 are located at different positions in the circumferential direction of the bearing housing 20. For example, the flow passage 22 is located at a position point-symmetrical with respect to the central axis A in a cross-sectional view perpendicular to the central axis A.

[0023] A groove 24 is formed on the outer peripheral surface 20b. The groove 24 extends in the circumferential direction of the bearing housing 20. The groove 24 is connected to the flow passage 21 and the flow passage 22. The groove 24 is, for example, a circumferential groove. However, the groove 24 is not limited to a circumferential groove. That is, the groove 24 does not have to go around the outer peripheral surface 20b along the circumferential direction of the bearing housing 20. The groove 24 has a first portion 24a and a second portion 24b. The first portion 24a is a portion of the groove 24 on the outer peripheral surface 20b side. The second portion 24b is a portion of the groove 24 that is located more inward than the first portion 24a in the radial direction of the bearing housing 20. The width of the first portion 24a in the direction of the central axis A is larger than the width of the second portion 24b in the direction of the central axis A. The width of the second portion 24b in the direction of the central axis A is smaller than the outer diameter of the elastic member 30a. The groove 24 is connected to the flow path 21 and the flow path 22 at the second portion 24b.

[0024] A groove 25 is formed on the outer peripheral surface 20b. The groove 25 extends in the circumferential direction of the bearing housing 20. The groove 25 is connected to the flow passage 21 and the flow passage 22. The groove 25 is, for example, a circumferential groove. However, the groove 25 is not limited to a circumferential groove. That is, the groove 25 does not have to go around the outer peripheral surface 20b along the circumferential direction of the bearing housing 20. The groove 25 has a first portion 25a and a second portion 25b. The first portion 25a is a portion of the groove 25 on the outer peripheral surface 20b side. The second portion 25b is a portion of the groove 25 that is located more inward than the first portion 25a in the radial direction of the bearing housing 20. The width of the first portion 25a in the direction of the central axis A is larger than the width of the second portion 25b in the direction of the central axis A. The width of the second portion 25b in the direction of the central axis A is smaller than the outer diameter of the elastic member 30b. The groove 25 is connected to the flow passages 21 and 22 at the second portion 25b. The grooves 24 and 25 are spaced apart from each other in the direction of the central axis A. In the direction of the central axis A, the groove 24 is closer to the first end 10a than the groove 25.

[0025] A groove 26 is formed in the outer peripheral surface 20b. The groove 26 extends in the circumferential direction of the bearing housing 20. The grooves 24 and 25 are formed in the bottom surface of the groove 26. That is, one end of the groove 26 in the direction of the central axis A is closer to the first end 10a than the groove 24, and the other end of the groove 26 in the direction of the central axis A is closer to the second end 10b than the groove 25.

[0026] The elastic member 30a closes the opening of the groove 24. The elastic member 30a is disposed in the groove 24. More specifically, the elastic member 30a is disposed in the first portion 24a. The elastic member 30b closes the opening of the groove 25. The elastic member 30b is disposed in the groove 25. More specifically, the elastic member 30b is disposed in the first portion 25a. The elastic member 30a and the elastic member 30b are, for example, annular members. The elastic member 30a and the elastic member 30b are, for example, O-rings.

[0027] The cooling liquid supplied from the supply port 23 is supplied to the flow passage 21. A part of the cooling liquid that has flowed through the flow passage 21 and reached the groove 25 flows through the groove 25 into the flow passage 22. The remainder of the cooling liquid that has flowed through the flow passage 21 and reached the groove 25 flows directly through the flow passage 22. The cooling liquid that has flowed through the flow passage 22 and reached the groove 24 flows through the groove 24 into the flow passage 22, and merges with the cooling liquid that has flowed through the groove 25 and reached the flow passage 22. The opening of the groove 24 is closed by the elastic member 30a, and the opening of the groove 25 is closed by the elastic member 30b, so that the cooling liquid is prevented from leaking out of the bearing housing 20.

[0028] The cover 40 is attached to the outer peripheral surface 20b. More specifically, the cover 40 is disposed in the groove 26. The thickness of the cover 40 is preferably equal to or less than the depth of the groove 26. Since the cover 40 is attached to the outer peripheral surface 20b, the elastic members 30a and 30b are prevented from coming off the grooves 24 and 25, respectively, due to the pressure of the coolant.

[0029] The bearing sleeve 50 has a first member 51 and a second member 52. The first member 51 and the second member 52 are cylindrical and extend in the direction of the central axis A. The first member 51 and the second member 52 are annular in a cross-sectional view perpendicular to the central axis A. The first member 51 has a first end 51a and a second end 51b in the direction of the central axis A. The second end 51b is on the opposite side to the first end 51a. The first end 51a is on the first end 10a side, and the second end 51b is on the second end 10b side. The second member 52 has a first end 52a and a second end 52b in the direction of the central axis A. The second end 52b is on the opposite side to the first end 52a. The first end 52a is on the second end 10b side, and the second end 52b is on the first end 10a side.

[0030] The first member 51 and the second member 52 are arranged in the direction of the central axis A such that the second ends 51b and 52b face each other with a gap therebetween. The first member 51 has an inner peripheral surface 51c, an outer peripheral surface 51d, and an end face 51e. The end face 51e is an end face on the first end 51a side of the first member 51. The end face 51e faces the enlarged diameter portion 11 with a small gap therebetween. The second member 52 has an inner peripheral surface 52c, an outer peripheral surface 52d, and an end face 52e. The end face 52e is an end face on the first end 52a side of the second member 52. The end face 52e faces the enlarged diameter portion 12 with a small gap therebetween.

[0031] The first member 51 has an expanded diameter portion 51f. The first member 51 protrudes in a direction perpendicular to the central axis A at the expanded diameter portion 51f. Preferably, the outer diameter of the first member 51 at the expanded diameter portion 51f is equal to the outer diameter of the rotating shaft 10 at the expanded diameter portion 11. The second member 52 has an expanded diameter portion 52f. The second member 52 protrudes in a direction perpendicular to the central axis A at the expanded diameter portion 52f. Preferably, the outer diameter of the second member 52 at the expanded diameter portion 52f is equal to the outer diameter of the rotating shaft 10 at the expanded diameter portion 11.

[0032] The bearing sleeve 50 is attached to the inner peripheral surface 20a. More specifically, the outer peripheral surface 51d and the outer peripheral surface 52d are in contact with the inner peripheral surface 20a. The enlarged diameter portions 51f and 52f sandwich the bearing housing 20 in the direction of the central axis A. The inner peripheral surfaces 51c and 52c face the outer peripheral surface of the rotating shaft 10 (first portion 13) with a small gap therebetween.

[0033] A flow passage 53 is formed inside the first member 51, and a flow passage 54 is formed inside the second member 52. A flow passage 27 and a flow passage 28 are formed inside the bearing housing 20. The flow passage 53 and the flow passage 54 are connected to the flow passage 27. The flow passage 53 opens at the inner circumferential surface 51c and the end face 51e. The flow passage 54 opens at the inner circumferential surface 52c and the end face 52e. The flow passage 27 is connected to the outside of the bearing housing 20 on the side opposite to the flow passages 53 and 54.

[0034] Air is supplied to the flow passage 53 and the flow passage 54 through the flow passage 27. The air supplied to the flow passage 53 is ejected from the inner circumferential surface 51c and the end surface 51e, and the air supplied to the flow passage 54 is ejected from the inner circumferential surface 52c and the end surface 52e. The pressure of this air supports the load applied to the rotating shaft 10 in the direction of the central axis A and in a direction perpendicular to the central axis A while the rotating shaft 10 is rotating around the central axis A. That is, in the spindle device 100, the rotating shaft 10 is supported by the hydrostatic bearing so as to be rotatable around the central axis A. The air ejected from the inner circumferential surface 51c, the end surface 51e, the inner circumferential surface 52c, and the end surface 52e passes through the space between the first member 51 and the second member 52 and the flow passage 28, and is discharged to the outside of the bearing housing 20.

[0035] The motor housing 60 has a cylindrical shape extending in the direction of the central axis A. The motor housing 60 has a circular ring shape in a cross-sectional view perpendicular to the central axis A. One end of the motor housing 60 in the direction of the central axis A is closed by a cover 70. A through hole 71 is formed in the cover 70. The through hole 71 penetrates the cover 70 along the thickness direction (the direction of the central axis A). The other end of the motor housing 60 in the direction of the central axis A is attached to the bearing housing 20. The enlarged diameter portion 12 and the second portion 14 are inside the motor housing 60. The second end 10b protrudes from the through hole 71.

[0036] The motor housing 60 has an inner circumferential surface 60a and an outer circumferential surface 60b. Fig. 6 is a first perspective view of the motor housing 60. Fig. 7 is a second perspective view of the motor housing 60 as viewed from direction VII in Fig. 6. As shown in Figs. 6 and 7, a plurality of grooves 61 are formed in the outer circumferential surface 60b. The grooves 61 are circumferential grooves formed along the circumferential direction of the motor housing 60. Two grooves 61 adjacent to each other in the direction of the central axis A are disposed with an interval therebetween.

[0037] A notch 62 is formed in the outer circumferential surface 60b between two adjacent grooves 61. The two adjacent grooves 61 are connected to each other by the notch 62. The notch 62 is formed, for example, along the direction of the central axis A.

[0038] The notches 62 arranged at odd numbers as counted from one end side of the motor housing 60 in the direction of the central axis A are referred to as notches 62a, and the notches 62 arranged at even numbers as counted from one end side of the motor housing 60 in the direction of the central axis A are referred to as notches 62b. The notches 62a are arranged in a row along the direction of the central axis A, and the notches 62b are arranged in a row along the direction of the central axis A. The row of the notches 62a is located at a different position from the row of the notches 62b in the circumferential direction of the motor housing 60. More specifically, the row of the notches 62a is located at a point-symmetric position to the row of the notches 62b with respect to the central axis A.

[0039] A flow passage 63 is formed inside the motor housing 60. The flow passage 63 extends in the direction of the central axis A. One end of the flow passage 63 is connected to the groove 61, and the other end is connected to the flow passage 22. As a result, the groove 61 is fluidly connected to the flow passage 22.

[0040] The motor 80 has a stator 81 and a rotor 82. The stator 81 is attached to the inner circumferential surface 60a. The stator 81 is composed of, for example, a plurality of coil bodies arranged along the circumferential direction of the motor housing 60. The rotor 82 is attached to the rotating shaft 10 (second part 14) so ​​as to face the stator 81 in the radial direction of the motor housing 60. The rotor 82 is, for example, a permanent magnet. In the motor 80, the plurality of coil bodies constituting the stator 81 are sequentially excited along the circumferential direction of the motor housing 60 by a signal from a motor driver circuit (not shown), thereby rotating the rotor 82. In accordance with this rotation, the rotating shaft 10 to which the rotor 82 is attached rotates around the central axis A. The motor 80 is, for example, an induction motor or a PM (Permanent Magnet) motor. When the motor 80 is an induction motor, the rotor 82 is an electromagnetic steel plate, and when the motor 80 is a PM motor, the rotor 82 is a permanent magnet.

[0041] The cover 90 is attached to the outer peripheral surface 60b so as to cover the groove 61. A flow path is defined by the inner peripheral surface of the cover 90 and the groove 61. An outlet 91 is formed in the cover 90. The outlet 91 penetrates the cover 90 so as to communicate with the flow path defined by the inner peripheral surface of the cover 90 and the groove 61. The coolant that has flowed through the flow path 22 is supplied via the flow path 63 to the flow path defined by the inner peripheral surface of the cover 90 and the groove 61. The coolant that has flowed through this flow path is discharged from the outlet 91. This allows the motor 80 to be cooled.

[0042] (Effects of the spindle device according to the embodiment) The effects of the spindle device 100 will now be described.

[0043] In the spindle device 100, a flow path for flowing the coolant for cooling the bearing sleeve 50 is defined by the flow path 21, the flow path 22, the groove 24, the groove 25, the elastic member 30a, and the elastic member 30b. The flow path 21 and the flow path 22 are formed inside the bearing housing 20. The groove 24 and the groove 25 are formed on the outer circumferential surface 20b. The elastic member 30a and the elastic member 30b are disposed in the groove 24 and the groove 25, respectively. Therefore, in the spindle device 100, by forming a flow path for flowing the coolant for cooling the bearing sleeve 50, the outer diameter dimension is not enlarged.

[0044] When the outer diameter of the spindle device increases to form a flow path for flowing a coolant to cool the bearing sleeve, it is necessary to maintain the outer diameter of the spindle device by reducing the outer diameter of the bearing housing. In this case, the outer diameter of the bearing sleeve also decreases as the outer diameter of the bearing housing is reduced, and the axial load (load in the direction of the central axis of the rotating shaft) that the bearing sleeve can support decreases.

[0045] However, in the spindle device 100, since the outer diameter does not increase in order to form a flow passage for flowing the coolant that cools the bearing sleeve 50, it is not necessary to reduce the outer diameter of the bearing housing 20. As a result, the spindle device 100 can maintain the axial load that the bearing sleeve 50 can support.

[0046] In the spindle device 100, the cover 40 is attached to the outer circumferential surface 20b so as to cover the elastic members 30a and 30b, so that the elastic members 30a and 30b are prevented from coming off due to the pressure of the coolant. Note that the cover 40 is disposed in the groove 26, and the thickness of the cover 40 is equal to or less than the depth of the groove 26, so that the outer dimensions of the spindle device 100 do not increase by attaching the cover 40 to the outer circumferential surface 20b.

[0047] When groove 24 has first portion 24a and second portion 24b (groove 25 has first portion 25a and second portion 25b), elastic member 30a (elastic member 30b) stops at the step between first portion 24a and second portion 24b (step between first portion 25a and second portion 25b), so the installation position of elastic member 30a (elastic member 30b) is stabilized.

[0048] In the spindle device 100, the flow paths 21 and 22 are positioned point-symmetrically with respect to the central axis A in a cross-sectional view perpendicular to the central axis A. Therefore, the flow of the coolant flowing through the flow path 21 can be branched into two directions at the grooves 24 and 25.

[0049] In the spindle device 100, a plurality of grooves 61 are formed in the outer circumferential surface 60b, the grooves 61 being connected by notches 62 and being fluidly connected to the flow passage 22. In addition, in the spindle device 100, a cover 90 is attached to the outer circumferential surface 60b. Therefore, according to the spindle device 100, the motor 80 can be further cooled by the cooling liquid that has cooled the bearing sleeve 50.

[0050] When the groove 61 is a circumferential groove extending in the circumferential direction of the motor housing 60, machining for forming the groove 61 is easy. When the row of the notches 62a and the row of the notches 62b are positioned point-symmetrically with respect to the central axis A, the cooling liquid can be supplied evenly to the outer circumferential surface 60b, improving the cooling efficiency of the motor 80.

[0051] (First Modification) Fig. 8 is a first cross-sectional view of the spindle device 100 according to the first modified example. Fig. 9 is a second cross-sectional view of the spindle device 100 according to the second modified example. Fig. 8 shows a cross-section at a position corresponding to II-II in Fig. 1. Fig. 9 shows a cross-section at a position corresponding to III-III in Fig. 1. As shown in Figs. 8 and 9, groove 24 and groove 25 are provided with partitions 24c and 25c, respectively.

[0052] In the spindle device 100 according to the first modified example, the flow passages 21 and 22 are arranged such that a line connecting the central axis A and the center of the flow passage 21 forms an angle of 90° or less with a line connecting the central axis A and the center of the flow passage 22 in a cross-sectional view perpendicular to the central axis A. This angle is preferably 45° or less.

[0053] The partition portion 24c is disposed between the flow passages 21 and 22 in the circumferential direction of the bearing housing 20. The partition portion 24c protrudes from the bottom surface of the groove 24 along the radial direction of the bearing housing 20. The partition portion 25c is disposed between the flow passages 21 and 22 in the circumferential direction of the bearing housing 20. The partition portion 25c protrudes from the bottom surface of the groove 25 along the radial direction of the bearing housing 20. This causes the flow of the coolant flowing through the grooves 24 and 25 to be a unidirectional flow. The partition portion 24c and the partition portion 25c may be part of the bearing housing 20 or may be a separate member from the bearing housing 20.

[0054] (Second Modification) In the spindle device 100 according to the second modified example, the groove 61 may be a spiral groove instead of a circumferential groove. Note that in the spindle device 100 according to the second modified example, the notch 62 is not formed in the outer circumferential surface 60b.

[0055] (Third Modification) In the spindle device 100 according to the third modified example, one or more rolling bearings that support the rotating shaft 10 rotatably about the central axis A may be used instead of the bearing sleeve 50. Note that in the spindle device 100 according to the third embodiment, no flow path 27 is formed inside the bearing housing 20.

[0056] (Fourth and Fifth Modifications) FIG. 10 is a perspective view of a spindle device 100 according to a fourth modified example. As shown in FIG. 10, the cover 40 may be a plate-shaped member and wrapped around the outer circumferential surface 20b (groove 26). In this case, the cover 40 can be easily attached. FIG. 11 is a perspective view of a spindle device 100 according to a fifth modified example. As shown in FIG. 11, the cover 40 may be divided into a plurality of parts in the circumferential direction. For example, the cover 40 may be divided into two parts, a divided cover 40a and a divided cover 40b, in the circumferential direction. However, the number of divisions of the cover 40 is not limited to two. In this case, the cover 40 can be easily attached.

[0057] Although the embodiment of the present invention has been described above, the above-mentioned embodiment can be modified in various ways. The scope of the present invention is not limited to the above-mentioned embodiment. The scope of the present invention is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. [Industrial Applicability]

[0058] The above-described embodiment is particularly advantageously applied to an air spindle device for a processing machine. [Explanation of symbols]

[0059] 100 spindle device, 10 rotating shaft, 10a first end, 10b second end, 11 enlarged diameter portion, 12 enlarged diameter portion, 13 first portion, 14 second portion, 20 bearing housing, 20a inner peripheral surface, 20b outer peripheral surface, 21 flow passage, 22 flow passage, 23 supply port, 24 groove, 24a first portion, 24b second portion, 24c partition portion, 25 groove, 25a first portion, 25b second portion, 25c partition portion, 26 groove, 27 flow passage, 28 flow passage, 30a elastic member, 30b elastic member, 40 cover, 40a split cover, 40b split cover, 50 bearing sleeve, 51 first member, 51a first end, 51b second end, 51c inner peripheral surface, 51d outer peripheral surface, 51e end surface, 51f Enlarged diameter portion, 52 second member, 52a first end, 52b second end, 52c inner circumferential surface, 52d outer circumferential surface, 52e end surface, 52f enlarged diameter portion, 53 flow path, 54 flow path, 60 motor housing, 60a inner circumferential surface, 60b outer circumferential surface, 61 groove, 62 notch, 62a notch, 62b notch, 63 flow path, 70 cover, 71 through hole, 80 motor, 81 stator, 82 rotor, 90 cover, 91 discharge port.

Claims

1. A rotation axis; a cylindrical bearing housing extending in the direction of a central axis of the rotating shaft; a bearing attached to an inner circumferential surface of the bearing housing and rotatably supporting the rotating shaft; A first elastic member, A first flow passage and a second flow passage extending in a direction of the central axis of the bearing housing are formed inside the bearing housing, a first groove is formed on an outer circumferential surface of the bearing housing, the first groove extending in a circumferential direction of the bearing housing and connected to the first flow path and the second flow path; the first elastic member closes an opening of the first groove, The spindle device further comprises a first cover attached to the outer circumferential surface of the bearing housing so as to cover the first elastic member.

2. The spindle device according to claim 1 , wherein a partition is disposed between a portion of the first groove connected to the first flow passage and a portion of the first groove connected to the second flow passage.

3. 3. The spindle device according to claim 1, wherein the first flow passage and the second flow passage are located at different positions from each other in a circumferential direction of the bearing housing.

4. Further comprising a second elastic member, a second groove is formed in the outer circumferential surface of the bearing housing, the second groove extending in a circumferential direction of the bearing housing, connected to the first flow path and the second flow path, and spaced apart from the first groove in a direction of the central axis of the bearing housing; The spindle device according to any one of claims 1 to 3, wherein the second elastic member closes an opening of the second groove.

5. a cylindrical motor housing extending in a direction of the central axis of the bearing housing; A motor; and a second cover. the motor includes a stator attached to an inner circumferential surface of the motor housing, and a rotor attached to the rotary shaft so as to face the stator in a radial direction of the motor housing, At least one third groove is formed in the outer circumferential surface of the motor housing, the third groove extending in a circumferential direction of the motor housing and fluidly connected to the second flow passage, The spindle device according to any one of claims 1 to 4, wherein the second cover is attached to an outer circumferential surface of the motor housing so as to cover the at least one third groove.

6. the at least one third groove is a plurality of circumferential grooves spaced apart from one another in a direction of the central axis of the rotation shaft, The spindle device according to claim 5 , wherein two of the plurality of circumferential grooves adjacent to each other in a direction of the central axis of the rotation shaft are connected to each other.

7. The spindle device according to any one of claims 1 to 6, wherein the bearing is a hydrostatic bearing that supports a load from the rotating shaft in the direction of the central axis of the rotating shaft and in a direction perpendicular to the central axis of the rotating shaft.

8. A third flow path is formed inside the motor housing, The bearing housing is provided with a supply port that is connected to the first flow path and through which the coolant is supplied, a discharge port is formed in the second cover, the discharge port being connected to a fourth flow passage defined by the at least one third groove and the second cover, and through which the cooling liquid is discharged; The spindle device according to claim 5 , wherein one end and the other end of the third flow passage are connected to the second flow passage and the fourth flow passage, respectively.

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