Rotating device

Abstract

To provide a rotating device configured to suppress heat of a rotor from causing defect thereon.SOLUTION: The rotating device comprises an enclosure, a motor, and a shaft, where the motor and the shaft are arranged in the enclosure concentrically with each other. The motor has a stator and a rotor, where the stator is arranged to surround the rotor and the rotor is configured to rotate together with the shaft. The shaft is arranged inside the rotor, and a fluid conveying structure part is provided at an outer periphery part of the shaft. The fluid conveying structure part is configured to be able to convey fluid in the enclosure, when the shaft is rotated, and the fluid conveying structure part moves the fluid between the fluid conveying structure part and an inner periphery part of the rotor, in a radial direction of the shaft.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Patent Document 1 discloses a rotating device equipped with a motor having a stator and a rotor. The rotating device of Patent Document 1 has cooling grooves formed on the outer peripheral surface of the stator, and the stator can be cooled by supplying a cooling medium to the cooling grooves. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-214492 Summary of the Invention [Problem to be solved by the invention]

[0004] When a rotor is rotated, it generates heat due to iron loss. When the rotor generates heat, the heat is transferred to the components around the rotor (e.g., bearings, etc.), causing the components to thermally expand. The rotating device of Patent Document 1 does not have a rotor cooling mechanism, which may cause the components around the rotor to thermally expand, resulting in malfunction of the rotating device.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a rotating device that can suppress the occurrence of problems due to heat of the rotor. [Means for solving the problem]

[0006] According to the present invention, there is provided a rotating device comprising a housing, a motor, and a shaft, wherein the motor and the shaft are arranged coaxially within the housing, the motor has a stator and a rotor, the stator is arranged to surround the rotor, the rotor is configured to rotate together with the shaft, the shaft is arranged inside the rotor, and a fluid conveying structure is provided on the outer periphery of the shaft, the fluid conveying structure is configured to be able to convey fluid within the housing when the shaft is rotating, and the fluid conveying structure moves the fluid between the fluid conveying structure and the inner periphery of the rotor in the radial direction of the shaft.

[0007] In the rotating device of the present invention, the shaft is provided with a fluid transport structure, and as the shaft rotates, the fluid between the fluid transport structure and the inner periphery of the rotor moves radially along the shaft. As a result, the fluid that has moved radially along the shaft then moves along the inner periphery of the rotor, cooling the rotor. This makes it possible to prevent malfunctions caused by heat generated by the rotor as it rotates.

[0008] Various embodiments of the present invention will be described below as examples, and the embodiments described below can be combined with each other. Preferably, there is provided a rotating device in which the fluid transport structure has a plurality of protrusions, and the plurality of protrusions are arranged so as to be aligned in the circumferential direction of the shaft. Preferably, a rotating device is provided, wherein the protrusion extends in a direction parallel to the center of rotation of the shaft. Preferably, a rotating device is provided in which the protrusion extends helically in a direction parallel to the center of rotation of the shaft. Preferably, a rotating device is provided in which the protrusion is formed so as to taper in the radial direction of the shaft. Preferably, a rotating device is provided in which the fluid transport structure faces the inner periphery of the rotor in spaced relation. Preferably, the rotor further comprises a bracket, the bracket being provided at an end of the shaft, the rotor being attached to the bracket, and a groove being formed on a surface of the bracket. The groove is configured to allow the fluid moved in the radial direction of the shaft by the fluid transport structure to pass through. Preferably, the rotating device is provided with a supply port and a discharge port in the housing, and the fluid flows into the housing through the supply port and is discharged from the housing through the discharge port. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a rotation device 100 according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA shown in FIG. [Figure 3] Fig. 3A is a perspective view of the shaft 5 shown in Fig. 2. Fig. 3B is a front view of the shaft 5 shown in Fig. 3A. [Figure 4] 4 is an enlarged view showing the protrusion 50 shown in region B in FIG. 3B and the opposing rotor 2B. In FIG. 4, the flow of fluid or the like in the protrusion 50 is schematically shown. [Figure 5] Fig. 5A is a perspective view of the bracket 8 shown in Fig. 2. Fig. 5B is a front view of the bracket 8 shown in Fig. 5A. [Figure 6] 6A and 6B are explanatory diagrams of the flow of fluid when the shaft 5 is rotating. Fig. 6A is an enlarged view of the rectangular dashed line area A shown in Fig. 2, and Fig. 6B is an enlarged view of the rectangular dashed line area B shown in Fig. 2. [Figure 7] Figure 7A is a perspective view of a shaft 5 having a fluid transport structure 5C having a different configuration from that shown in Figures 3A and 3B. Figure 7B is a front view of the shaft 5 shown in Figure 7A. DETAILED DESCRIPTION OF THE INVENTION

[0010] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an independent invention.

[0011] 1. Configuration Description As shown in FIGS. 1 and 2, the rotation device 100 includes a housing 1, a motor 2, a sealant 3, a rotary table 4, a shaft 5, a bearing 6, and a bracket 8. In this embodiment, the rotation device 100 is an indexing device including a rotary table 4 having tapped holes 4A for fixing a workpiece, a jig, or the like. The rotation device 100 employs a so-called direct drive system, and is configured so that the rotary table 4 rotates integrally with a rotor 2B of the motor 2, which will be described later. The rotary table 4, the shaft 5, the bearing 6, and the bracket 8 can be made of metal.

[0012] 1-1 Cabinet 1 As shown in FIG. 2, the housing 1 houses the motor 2, shaft 5, bearing 6, and bracket 8. The motor 2, shaft 5, and bracket 8 are arranged coaxially within the housing 1. In other words, the centers of rotation of the rotor 2B, shaft 5, and bracket 8 correspond to the center line O. In this embodiment, the housing 1 is made up of multiple members, and specifically, the housing 1 includes a main body 1A, a front cover 1B, a rear cover 1C, and a box 1D.

[0013] <Main body 1A> As shown in FIG. 2, the main body 1A is cylindrical and is provided to surround the motor 2, shaft 5, bearing 6, and bracket 8. A front cover 1B, a rotary table 4, and the like are disposed on the front side of the main body 1A, thereby closing the front side of the main body 1A. A rear cover 1C is disposed on the rear side of the main body 1A, thereby closing the rear side of the main body 1A. The front corresponds to the direction of arrow Dr1 (direction from the rear cover 1C toward the front cover 1B) shown in FIG. 2, and the rear corresponds to the direction of arrow Dr2 (direction from the front cover 1B toward the rear cover 1C) shown in FIG. 2. As shown in FIGS. 6A and 6B, a stator 2A of the motor 2 and an outer ring 6B of a bearing 6 (described later) are fixed to the inner circumferential surface of the main body 1A.

[0014] As shown in FIG. 2, the housing 1 is provided with a supply section 1a for supplying a fluid into the housing 1 and a discharge section 1b for discharging the fluid from inside the housing 1.

[0015] As shown in FIG. 2, the supply unit 1a has a pipe 1a1 and a throttle valve 1a2. The pipe 1a1 is connected to a fluid supply source, such as a compressor. In this embodiment, the fluid is a gas (air). The throttle valve 1a2 has a function of adjusting the amount of fluid supplied from the pipe 1a1 into the box 1D. The throttle valve 1a2 is connected to an end of the pipe 1a1, and has a fluid supply port 1a3 formed therein. The supply port 1a3 is provided in the box 1D and allows the fluid to flow into the housing 1. If the fluid supplied from the throttle valve 1a2 is a gas, it is preferably compressed. As shown in FIGS. 2 and 6B, the discharge portion 1b has a joint portion 1b1, a discharge passage 1b2, and a discharge port 1b3. The joint portion 1b1 is connected to the outer surface of the main body portion 1A. The discharge passage 1b2 is a through hole formed to communicate between the joint portion 1b1 and the discharge port 1b3. The discharge port 1b3 is disposed between the bearing 6 and the stator 2A in a direction parallel to the center line O. Note that a flow of fluid occurs from the supply unit 1a (high-pressure side) to the discharge unit 1b (low-pressure side). For this reason, it is preferable that the motor 2 be disposed between the supply unit 1a and the discharge unit 1b in a direction perpendicular to the center line O (see the direction Ar in FIG. 2). In addition, it is preferable that the motor 2 be disposed between the supply unit 1a and the discharge unit 1b in a direction parallel to the center line O. This ensures that the fluid passes through the motor 2 as it flows from the high-pressure side to the low-pressure side, enabling the motor 2 to be cooled efficiently. Furthermore, since high-temperature fluid tends to accumulate in the upper part of the space, the outlet 1b3 may be formed at a position on the housing 1 (main body 1A) that is equal to or higher than the height position of the center line O so that the high-temperature fluid can be easily discharged.

[0016] As shown in Fig. 2, a passage 1c, which is a through-hole, is formed in the main body 1A. The passage 1c is formed to connect the space inside the box 1D with a space Sp1 inside the main body 1A. As shown in Fig. 2, the space Sp1 is surrounded by the inner circumferential surface of the main body 1A, the motor 2, the bracket 8, and the rear cover 1C. The space Sp1 is also formed between the motor 2 and the bracket 8 and the rear cover 1C in a direction parallel to the center line O. 6A and 6B, a space Sp2 is also formed within the main body 1A. The space Sp2 is surrounded by the inner circumferential surface of the main body 1A, the bearing 6, the motor 2, and the shaft 5. The space Sp2 is also formed between the bearing 6 and the motor 2 in a direction parallel to the center line O.

[0017] <Front lid part 1B and rear lid part 1C> As shown in FIG. 2, the front cover 1B is an annular member disposed at the front end of the main body 1A. The front cover 1B has a plurality of holes formed therein into which fixing members bt1, such as bolts, are inserted, and the front cover 1B is fixed to the main body 1A via the fixing members bt1. A rotary table 4 is disposed inside the front cover 1B. A bearing 6 (bearing outer ring 6B) is disposed on the back surface of the front cover 1B. The rear cover 1C is a plate-like member disposed at the rear end of the main body 1A. The rear cover 1C is connected to the main body 1A by, for example, bolts or the like.

[0018] <Box 1D> 1 and 2, the box 1D is a box-shaped member attached to the outer surface of the main body 1A. Inside the box 1D, cables and electrical devices (not shown) used for controlling the rotating device 100 are provided. Power is supplied to the stator 2A of the motor 2 through a cable extending from the box 1D.

[0019] 1-2 Motor 2 2, the motor 2 is housed in the housing 1 and has the function of integrally rotating the shaft 5, the rotary table 4, and the bracket 8. The motor 2 includes a stator 2A and a rotor 2B.

[0020] <Stator 2A> 2, the stator 2A is fixed to the inner circumferential surface of the main body 1A and is disposed so as to surround the rotor 2B. Electric power is supplied to the windings of the stator 2A via a cable (not shown) extending from the box 1D.

[0021] <Rotor 2B> As shown in FIG. 2, the rotor 2B is formed of, for example, a permanent magnet and is disposed inside the stator 2A with a gap therebetween. The rotor 2B is configured in an annular shape and is disposed so as to surround the shaft 5. The rotor 2B is connected to a bracket 8 via a fixing member bt4 formed, for example, by a bolt, and the bracket 8 is connected to the shaft 5 via a fixing member bt3 formed, for example, by a bolt. Therefore, the rotor 2B is configured to rotate integrally with the shaft 5 and the like. As shown in FIGS. 6A and 6B, the rotor 2B has end portions 2a and 2b, an inner peripheral portion 2c, and an outer peripheral portion 2d. The end portion 2a is provided on one side (front side) in a direction parallel to the center line O, and the end portion 2b is provided on the other side (rear side) in a direction parallel to the center line O. A bracket 8 is disposed on the end portion 2b, and the bracket 8 is connected to the rotor 2B via a fixing member bt3 formed, for example, by a bolt. The inner peripheral portion 2c is provided so as to face a fluid transport structure 5C of the shaft 5, which will be described later, and the outer peripheral portion 2d is provided so as to face the stator 2A.

[0022] 1-3 Rotary table 4 The turntable 4 is a portion to which, for example, a workpiece or a jig such as a chuck is fixed. That is, the turntable 4 has tapped holes 4A, and a workpiece or the like can be fixed to the turntable 4 via the tapped holes 4A. With the turntable 4 rotating, a cutting tool of a machine tool such as a machining center is pressed against the workpiece, thereby machining the workpiece. As shown in FIG. 2, the turntable 4 is disposed inside the front cover 1B with a gap therebetween, and a shaft 5 is disposed on the back side. The turntable 4 is connected to the shaft 5 via a fixing member bt2, which is formed, for example, by a bolt.

[0023] 1-4 Sealing material 3 2, the sealant 3 is disposed in the gap between the front cover 1B and the rotary table 4 so as to seal the gap. The sealant 3 is also disposed in front of the bearing 6. The provision of the sealant 3 in the rotary device 100 improves the airtightness of the space within the housing 1.

[0024] 1-5 Shaft 5 As shown in FIG. 2, the shaft 5 is disposed inside the rotor 2B. The shaft 5 is a columnar member extending in a direction parallel to the center line O. In other words, the shaft 5 has a front end 5a and a rear end 5b, and is a substantially cylindrical member extending from the front end 5a to the rear end 5b. A hole 5c is formed in the rear end 5b of the shaft 5, into which the fixing member bt3 is screwed. A plurality of steps are formed on the outer periphery of the shaft 5 in a direction parallel to the center line O. Specifically, an arrangement surface portion 5A, a protruding portion 5B, and a fluid transport structure portion 5C are formed on the outer periphery of the shaft 5.

[0025] <Arrangement surface section 5A and overhang section 5B> As shown in FIGS. 2 to 3B, an inner ring 6A of a bearing 6 is provided on the mounting surface 5A. The mounting surface 5A is formed at a position closer to the front end 5a than the protruding portion 5B and the fluid transport structure 5C. The protruding portion 5B is formed to protrude in the radial direction of the shaft 5 relative to the mounting surface 5A. The inner ring 6A of the bearing 6 is disposed on a step formed by the mounting surface 5A and the protruding portion 5B.

[0026] <Fluid transport structure 5C> The fluid transport structure 5C is configured to be able to transport the fluid within the housing 1 while the shaft 5 is rotating. Specifically, the fluid transport structure 5C has the function of moving the fluid between the fluid transport structure 5C and the inner periphery 2c of the rotor 2B in the radial direction of the shaft 5. The fluid moved in the radial direction of the shaft 5 then directly collides with the inner periphery 2c of the rotor 2B, thereby facilitating cooling of the inner periphery 2c of the rotor 2B.

[0027] As shown in Figures 6A and 6B, the fluid transport structure 5C is disposed inside the rotor 2B so as to face the inner periphery 2c of the rotor 2B. A space pt is provided between the fluid transport structure 5C and the inner periphery 2c of the rotor 2B. The flow of fluid in the space pt will be explained in "2. Explanation of Operation" below.

[0028] As shown in FIGS. 3A to 4, the fluid transport structure 5C has a plurality of protrusions 50 and a plurality of grooves 51. The protrusions 50 are formed so as to protrude in the radial direction of the shaft 5. The protrusions 50 are arranged at equal intervals in the circumferential direction of the shaft 5. As shown in FIGS. 3A and 3B, the protrusions 50 are formed so as to extend parallel to the center line O. The protrusions 50 have the function of moving the fluid around the fluid transport structure 5C (the fluid in the grooves 51 and the fluid between a pair of adjacent protrusions 50) along the protrusions 50 when the shaft 5 is rotating. This allows the protrusions 50 to move the fluid in the radial direction of the shaft 5. Note that, since the fluid transport structure 5C has a plurality of protrusions 50, the surface area of ​​the shaft 5 can be increased. In other words, the protrusions 50 also have the function of improving the cooling effect of the shaft 5 due to heat radiation.

[0029] As shown in FIG. 3B , in this embodiment, the angle θ between a pair of adjacent protrusions 50 is 15 degrees, but is not limited to this. Specifically, the angle θ (degrees) may be, for example, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 degrees, or may be within a range between any two of the values ​​exemplified here. Furthermore, the protrusions 50 may be arranged at non-equidistant intervals in the circumferential direction of the shaft 5. In this case, the angle θ between any pair of protrusions 50 may be any of the values ​​exemplified here or within a range between any two of the values ​​exemplified here.

[0030] As shown in Figures 6A and 6B, the protrusion 50 is provided so as to face the entire inner circumferential portion 2c of the rotor 2B in a direction parallel to the center line O. In other words, the width of the protrusion 50 in a direction parallel to the center line O is equal to or greater than the width of the rotor 2B. This makes it possible to effectively cool the entire surface of the inner circumferential portion 2c of the rotor 2B. Note that, in the direction parallel to the center line O, the protrusion 50 (fluid transport structure 5C) does not need to face the entire inner circumferential portion 2c of the rotor 2B, but only needs to face a portion of the inner circumferential portion 2c of the rotor 2B.

[0031] As shown in FIG. 4, the protrusion 50 is tapered in the radial direction of the shaft 5. Specifically, the protrusion 50 has an apex 50A and a pair of inclined surfaces 50B. The apex 50A is flat, and the inclined surfaces 50B are connected to both edges of the apex 50A. The inclined surfaces 50B extend from the apex 50A to the groove 51. The inclination angle α (degrees) of the inclined surfaces 50B is, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 90 degrees, and may be within a range between any two of the values ​​exemplified here. Here, the inclination angle α is the angle between a virtual line L1 and the inclined surface 50B. The virtual line L1 passes through the lower ends of the pair of inclined surfaces 50B and is perpendicular to the virtual line L2. The imaginary line L2 is a line that passes through the center line O (see FIGS. 3A and 3B) and the position P1 at the center of the top portion 50A.

[0032] The groove 51 is formed between a pair of adjacent protrusions 50. The groove 51 is formed so as to be recessed radially inward from the lower end of the inclined surface 50B. As shown in FIGS. 6A and 6B, when the shaft 5 is rotating, the fluid in the space Sp2 flows into the groove 51 (see flow w3).

[0033] The opposing distance d1 (mm) shown in FIG. 4 is, for example, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 mm, and may be within a range between any two of the numerical values ​​exemplified here. Here, as shown in FIG. 4, the opposing distance d1 is the distance on a virtual line L3, which is the distance between a center position P of the groove 51 and the inner circumferential portion 2c of the rotor 2B. The virtual line L3 is a line passing through the center line O and a center position P2 of the groove 51. The virtual line L4 corresponds to an inscribed circle passing through the center positions of the grooves 51. The position P2 is the intersection of the virtual line L3 and the virtual line L4, and the tangent to the virtual line L4 (inscribed circle) at the position P2 is perpendicular to the virtual line L3.

[0034] Furthermore, the fluid transport structure 5C faces the inner circumferential portion 2c of the rotor 2B with a gap therebetween. This prevents interference between the flow w2 and the flow w3 described below. The facing distance d2 (mm) shown in FIG. 4 is, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm, and may be within a range between any two of the values ​​shown here. As shown in FIG. 4, the facing distance d2 is the distance on the imaginary line L2, and is the distance between the center position P1 of the top portion 50A and the inner circumferential portion 2c of the rotor 2B.

[0035] 1-6 Bearing 6 As shown in FIGS. 6A and 6B, the bearing 6 is configured to rotatably support the shaft 5 and includes an inner ring 6A and an outer ring 6B. The inner ring 6A is fixed to the mounting surface 5A of the shaft 5. The outer ring 6B is fixed to the housing 1, and specifically, the outer ring 6B is provided so as to be sandwiched between the main body 1A and the front cover 1B. In addition to the inner ring 6A and the outer ring 6B, the bearing 6 also includes rolling elements (e.g., balls) provided so as to be interposed between the inner ring 6A and the outer ring 6B. The outer ring 6B supports the shaft 5 and other components (shaft 5, rotor 2B, and bracket 8) via the inner ring 6A and the rolling elements.

[0036] 1-7 Bracket 8 As shown in Fig. 2, the bracket 8 is provided at the rear end 5b of the shaft 5, and the rotor 2B is attached to the bracket 8. The rotation device 100 is provided with the bracket 8, so that the rotor 2B is supported on the shaft 5. As shown in Figs. 5A and 5B, the bracket 8 is provided with a base 8A, a first protrusion 8B, a groove 8C, a second protrusion 8D, and holes 8E and 8F.

[0037] <Base 8A and First Protrusion 8B> 5A and 5B, the base 8A is, for example, a circular plate-like member. The first protrusions 8B are arranged at equal intervals in the circumferential direction on the periphery of the base 8A. A groove 8C through which a fluid passes is formed between a pair of adjacent first protrusions 8B.

[0038] <Groove 8C> The grooves 8C are configured to allow passage of the fluid moved radially of the shaft 5 by the fluid-transporting structure 5C. As shown in FIGS. 5A and 5B, the grooves 8C are formed on the surface of the bracket 8. In this embodiment, the grooves 8C are formed in the base 8A, a pair of adjacent first protrusions 8B, and the second protrusion 8D. The grooves 8C are arranged at equal intervals in the circumferential direction of the base 8A. The grooves 8C have an inner end 8C1 and an outer end 8C2. The outer end 8C2 is located on the outer peripheral surface 8a of the base 8A, and the inner end 8C1 is located at the apex 8D1 of the second protrusion 8D. In other words, the grooves 8C extend in an L-shape from the outer peripheral surface 8a of the base 8A to the apex 8D1 of the second protrusion 8D.

[0039] As shown in FIG. 5B , in this embodiment, the angle φ between a pair of adjacent inner ends 8C1 is 30 degrees. The angle φ between a pair of adjacent outer ends 8C2 is also the same. The angle φ is not limited to 30 degrees. Specifically, the angle φ (degrees) may be, for example, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, or 120 degrees, or may be within a range between any two of the values ​​exemplified here. The grooves 8C may be arranged at non-equidistant intervals. In this case, the angle φ between any pair of grooves 8C may be any of the values ​​exemplified here or within a range between any two of the values ​​exemplified here.

[0040] <Second protrusion 8D> 5A and 5B, the second protrusion 8D is formed to protrude from the base 8A in a direction parallel to the center line O, and an apex 8D1 of the second protrusion 8D protrudes further than the first protrusion 8B. The second protrusion 8D is formed in an annular shape. The rear end 5b of the shaft 5 is inserted inside the second protrusion 8D.

[0041] <Hole 8E, 8F> 5A and 5B, the holes 8E and 8F are through holes formed parallel to the center line O. The fixing member bt4 is inserted into the hole 8E, and the fixing member bt3 is inserted into the hole 8F.

[0042] 2 Operation explanation Assume that the shaft 5 and rotor 2B are rotating in the direction R shown in Figure 4. When the motor 2 is running, the stator 2A generates heat due to copper loss, and the rotor 2B generates heat due to iron loss. Note that copper loss is a loss that occurs when current flows through the windings of the stator 2A, and iron loss is a type of loss represented by hysteresis loss and eddy current loss. Hysteresis loss is a friction loss between molecules that occurs when the direction and arrangement of magnetic molecules in the iron core changes due to fluctuations in the magnitude and direction of the magnetic flux within the iron core. Therefore, in the rotation device 100, a cooling fluid is supplied into the box 1D of the housing 1 through the supply port 1a3 of the supply unit 1a. The fluid that has flowed into the box 1D passes through the passage 1c of the main body 1A and flows into the space Sp1 of the main body 1A.

[0043] As the shaft 5 rotates, a fluid flow w1 is generated in the space pt along the sidewall of the groove 51 and the inclined surface 50B of the protrusion 50. The flow w1 flows from the shaft 5 toward the inner periphery 2c of the rotor 2B. In other words, the direction of the flow w1 includes a radial component of the shaft 5. The fluid corresponding to the flow w1 collides with the inner periphery 2c of the rotor 2B, reducing its kinetic energy. As a result, the pressure of the fluid near the inner periphery 2c of the rotor 2B increases (Bernoulli's principle). As the fluid pressure increases, a flow w2 is generated toward the end 2a of the rotor 2B, as shown in FIGS. 6A and 6B, and the fluid flows into the space Sp2 where the pressure is low. Concurrently, a flow w2 is generated toward the end 2b of the rotor 2B, and the fluid flows into the space Sp1 via the groove 8C where the pressure is low. The fluid that flows into the space Sp1 or the space Sp2 collides with, for example, the stator 2A or the inner wall of the housing 1, loses speed, and diffuses. In this manner, in the embodiment, by generating a flow w1 that causes the fluid to directly collide with the inner circumferential portion 2c of the rotor 2B and a flow w2 that moves along the inner circumferential portion 2c, it is possible to directly cool the inner circumferential portion 2c of the rotor 2B. In the embodiment, the fluid corresponding to the flow w2 flows into the space Sp1 or the space Sp2 and diffuses throughout the entire space within the housing 1, making it possible to suppress the accumulation of heat around the motor 2.

[0044] Furthermore, the fluid that has diffused into the space Sp2, etc. flows again as flow w3 into the fluid transport structure 5C (space pt). In other words, because high-pressure flow w2 is generated, the pressure in the portion of the space pt on the root side of the groove 51 and the protrusion 50 is relatively low. For this reason, the fluid that has diffused into the space Sp2, etc. flows into the fluid transport structure 5C as flow w3 in the opposite direction to flow w2. In this way, in the embodiment, the fluid around the rotor 2B is replaced, so the temperature drops and the rotor 2B can be cooled by the fluid, thereby improving cooling efficiency.

[0045] The fluid in the space Sp2 absorbs heat from the motor 2 and the temperature rises. Therefore, the fluid in the space Sp2 flows into the discharge passage 1b2 via the discharge port 1b3 and is discharged to the outside of the housing 1. At the same time, fluid is supplied into the housing 1 via the supply port 1a3 of the supply unit 1a, and unheated fluid is again supplied to the motor 2. In other words, the rotation device 100 cools the motor 2 more effectively by replacing the fluid in the housing 1.

[0046] 3. Functions and Effects of the Embodiments Direct-drive rotating devices, such as the rotating device 100 according to the embodiment, tend to trap heat from the motor installed inside the device, causing thermal expansion of components such as bearings. In particular, bearings are components that ensure smooth axial rotation of the shaft, so thermal expansion of the bearings affects the performance of the rotating device. Therefore, the shaft 5 of the rotating device 100 according to the embodiment is provided with a fluid conveying structure 5C. As the shaft 5 rotates, fluid between the fluid conveying structure 5C and the inner circumferential portion 2c of the rotor 2B moves radially along the shaft 5. The fluid that moves radially along the shaft 5 then moves along the inner circumferential portion 2c of the rotor 2B, cooling the rotor 2B. This suppresses heat transfer from the rotor 2B to other peripheral components (such as the bearing 6), thereby suppressing thermal expansion of the peripheral components (such as the bearing 6) and preventing malfunctions in the rotating device 100.

[0047] In a direct-drive rotating device, when the rotor rotates at high speed, friction between the shaft surface and the fluid creates a layered flow on the circumferential surface of the shaft. For example, if the fluid is a gas, a layered entrained airflow (wd) (see Figure 4) is created on the circumferential surface of the shaft. This layered flow (entrained airflow) prevents heat from being dissipated from the shaft surface to the fluid. In contrast, in the rotation device 100 according to the embodiment, the flow w1 is generated, which can inhibit the formation of a laminar flow (entrained air), thereby preventing heat dissipation from being impeded. Furthermore, in the rotation device 100 according to the embodiment, in addition to the flow w1, flows w2 and w3 are generated, so even if a laminar flow (entrained air) is formed to some extent, the fluids forming the laminar flows can be replaced, thereby preventing heat dissipation from being impeded.

[0048] In the rotating device 100 according to this embodiment, the bracket 8 has a groove 8C, which reduces the contact area between the bracket 8 and the rotor 2B. This reduces heat transfer from the rotor 2B to the bracket 8, thereby suppressing temperature increases in the shaft 5 and bracket 8, and ultimately suppressing temperature increases in the bearing 6 that contacts the shaft 5. This reduces thermal expansion of various components in the rotating system. Note that the rotor 2B is effectively cooled by the fluid being directly impinged on it by the fluid transport structure 5C.

[0049] In the rotating device 100 according to this embodiment, the outlet 1b3 is disposed between the bearing 6 and the stator 2A (motor 2) in a direction parallel to the center line O. This makes it easier for the fluid that has received heat from the motor 2 and has increased in temperature to be discharged from the outlet 1b3 before moving toward the bearing 6, making it possible to suppress thermal expansion of the bearing 6.

[0050] 4. Other embodiments Although the fluid has been described as being a gas (air in the embodiment), it is not limited to this and may be a liquid. Furthermore, when the fluid is a gas, for example, nitrogen or carbon dioxide may also be used. Furthermore, the fluid supplied from the supply port 1a3 into the box 1D may be cooled in advance. In the embodiment, the shape of the protrusion 50 is described as being trapezoidal in a cross section perpendicular to the center line O, but this is not limited to this. For example, the shape of the protrusion 50 in a cross section perpendicular to the center line O may be triangular or a quadrangle other than a trapezoid. In the embodiment, the rotary table 4, the bracket 8, and the shaft 5 are described as separate parts, but this is not limited to this, and at least two of these (for example, the rotary table 4 and the shaft 5, the bracket 8 and the shaft 5, or all of these) may be integrally formed. In the embodiment, the bracket 8 has the groove 8C, but this is not limited to this. The bracket 8 may have a through hole (not shown) formed therein instead of the groove 8C. The through hole may be formed, for example, in an L-shape from the outer peripheral surface 8a of the base 8A to the apex 8D1 of the second protrusion 8D. In the embodiment, the rotor 2B is attached to the bracket 8, but this is not limiting. The rotor 2B may be attached to the shaft 5. In this case, the rotor 2B can be connected to the protruding portion 5B of the shaft 5 via a fixing member, for example. In addition, it is preferable that a gap is formed between the rotor 2B and the protruding portion 5B to allow a fluid to pass through. 7A and 7B, the protrusion 50 may extend spirally in a direction parallel to the center line O. This configuration has the effect of increasing the component of the fluid flow parallel to the center line O. [Explanation of symbols]

[0051] 1: Housing 1a3: Supply port 1b3 :Exhaust port 2: Motor 2A: Stator 2B: Rotor 2c: Inner circumference 5: Shaft 5C: Fluid transport structure 8: Bracket 8C:Groove 50:Protrusion 100: Rotating device

Claims

1. The motor includes a housing, a motor, and a shaft. The motor and the shaft are coaxially arranged within the housing, The motor includes a stator and a rotor. the stator is disposed to surround the rotor, the rotor is configured to rotate with the shaft; the shaft is disposed inside the rotor, and a fluid transport structure is provided on an outer periphery of the shaft; A rotating device, wherein the fluid conveying structure is configured to be able to convey fluid within the housing when the shaft is rotating, and the fluid conveying structure moves the fluid between the fluid conveying structure and the inner peripheral portion of the rotor in the radial direction of the shaft.

2. 2. The rotation device according to claim 1, the fluid-transporting structure has a plurality of protrusions; A rotating device, wherein the plurality of protrusions are arranged in a line in the circumferential direction of the shaft.

3. 3. The rotation device according to claim 2, A rotating device, wherein the protrusion extends in a direction parallel to the center of rotation of the shaft.

4. 3. The rotation device according to claim 2, A rotating device, wherein the protrusion extends spirally in a direction parallel to the center of rotation of the shaft.

5. A rotation device according to any one of claims 2 to 4, A rotating device, wherein the protrusion is formed so as to taper in the radial direction of the shaft.

6. A rotating device according to any one of claims 1 to 5, The fluid transport structure faces the inner periphery of the rotor with a gap therebetween.

7. A rotating device according to any one of claims 1 to 6, Further comprising a bracket, the bracket is provided at an end of the shaft, and the rotor is attached to the bracket; A groove is formed on the surface of the bracket, A rotating device, wherein the groove portion is configured to allow the fluid moved in the radial direction of the shaft by the fluid transport structure portion to pass through.

8. A rotating device according to any one of claims 1 to 7, The housing is provided with a supply port and a discharge port, The fluid flows into the housing through the supply port and is discharged from the housing through the discharge port.

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