spindle assembly

Abstract

This spindle device comprises: a spindle-mounting body; a first rolling element bearing that is lubricated using grease; a spindle that is rotatably supported on the spindle-mounting body via the first rolling element bearing; a rotation-driving motor that causes the spindle to rotate; a spiral-shaped first cooling flow path formed as a groove in the outer peripheral surface of the spindle, the first cooling flow path being formed in at least a first region where the first rolling element bearing is positioned in the axial direction of the spindle, and being covered by the first rolling element bearing in the first region; and a first supply flow path that supplies, to the first cooling flow path, cooling gas for cooling the first rolling element bearing. The first supply flow path has a first radial-direction flow path formed spanning the spindle-mounting body and the spindle in the radial direction. Among first gaps, a pair of first axial-direction gaps located on either side of the first radial-direction flow path in the axial direction function as first apertures for reducing leakage of the cooling gas from the first radial-direction flow path.

Description

[Technical Field]

[0001] The present disclosure relates to a technique for a spindle device. [Background technology]

[0002] Conventionally, a spindle device in a machine tool has a spindle device main body, a rolling bearing, a spindle rotatably supported on the spindle device main body via the rolling bearing, and a cooling flow path that cools the rolling bearing (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 5-309545 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, the cooling flow path includes a main supply path formed in a draw bar (push rod) disposed in the shaft bore of the spindle, a communication hole extending radially from the tip of the main supply path to the outer circumferential surface of the draw bar, a spiral groove formed in the spindle and communicating with the communication hole, and a cylindrical body shrink-fitted to the spindle to cover the spiral groove. The rolling bearing, particularly the inner ring, is cooled by the coolant flowing through this spiral groove via the cylindrical body. In conventional technology, the cylindrical body reduces heat transfer to the inner ring. Furthermore, forming the main supply path in the draw bar can sometimes result in a complex flow path configuration for the cooling flow path. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to one aspect of the present disclosure, there is provided a spindle device comprising: a spindle device main body, a first rolling bearing lubricated with grease, a spindle rotatably supported by the spindle device main body via the first rolling bearing, the spindle having a front end located on the front side and a rear end located on the rear side, a rotary drive motor for rotating the spindle, a first spiral cooling channel formed as a groove on the outer peripheral surface of the spindle, the first cooling channel being formed in at least a first region in the axial direction of the spindle where the first rolling bearing is disposed and being covered by the first rolling bearing in the first region, and a cooling gas for cooling the first rolling bearing being supplied to the first cooling channel. and a first supply passage for supplying cooling gas to the first rolling bearing, the first supply passage having a first radial passage formed across the spindle body and the spindle in the radial direction so as to include a part of a first gap between the spindle body and the spindle in the radial direction, the first radial passage having a first front-side passage formed in the spindle body and a second front-side passage formed in the spindle through which the cooling gas from the first front-side passage flows, and a pair of first axial gaps in the first gap located on both sides of the first radial passage in the axial direction function as first throttles for reducing leakage of the cooling gas from the first radial passage. According to this aspect, the cooling gas can be supplied from the spindle body to the first cooling passage formed on the outer peripheral surface of the spindle by the first radial passage formed across the spindle body and the spindle in the radial direction, thereby preventing the passage configuration for cooling the first rolling bearing from becoming complicated. Furthermore, since the first rolling bearing covers the first cooling flow passage, the first rolling bearing can be directly cooled by the cooling gas flowing through the first cooling flow passage. (2) In the above aspect, a relationship may be established in which, due to the function as the first throttle, the flow rate of the cooling gas flowing from the first front-side passage into the second front-side passage is greater than the flow rate of the cooling gas leaking from the first front-side passage into the pair of first axial gaps. According to this aspect, a larger flow rate of the cooling gas is supplied to the first cooling passage, thereby enabling efficient cooling of the first rolling bearing. (3) In the above-described embodiment, the spindle may further include a mounting chamber located between an inner peripheral surface of the spindle device body and an outer peripheral surface of the spindle, and the rotation drive motor may be a direct drive motor provided in the mounting chamber. According to this embodiment, the spindle can be rotated by the direct drive motor. (4) In the above aspect, the cooling device may further include a first exhaust passage that exhausts the cooling gas flowing out of the first cooling passage to the outside, the first exhaust passage including: a first upstream exhaust passage that circulates the cooling gas flowing out of the first cooling passage into the arranging chamber, the first upstream exhaust passage being formed in the spindle; the arranging chamber; and a first downstream exhaust passage that exhausts the cooling gas in the arranging chamber to the outside, the first downstream exhaust passage being formed in the spindle main body. According to this aspect, the cooling gas flowing out of the first cooling passage can be used to cool the rotation drive motor located in the arranging chamber. (5) In the above aspect, a downstream end of the first upstream discharge flow path may be located between the rear one of the pair of first axial gaps and the rotation drive motor in the axial direction. According to this aspect, it is possible to prevent the cooling gas flowing out from the first upstream discharge flow path from leaking to the first rolling bearing through the first axial gap. (6) In the above embodiment, the distance in the radial direction between the axis of the main shaft and the downstream end of the first upstream exhaust passage may be the same as the distance between the axis and the outer circumferential surface of the rotor of the direct drive motor. According to this embodiment, the cooling gas flowing out from the downstream end of the first upstream exhaust passage can smoothly reach the rotor of the direct drive motor. This allows the direct drive motor to be efficiently cooled by the cooling gas. (7) In the above-described embodiment, the main spindle may further include a second rolling bearing located rearward of the first rolling bearing, the second rolling bearing being lubricated with grease; a spiral second cooling passage formed as a groove on the outer peripheral surface of the main spindle, the spiral second cooling passage being formed in a second region in the axial direction of the main spindle where at least the second rolling bearing is disposed and being covered by the second rolling bearing in the second region; and a second supply passage that supplies the cooling gas for cooling the second rolling bearing to the second cooling passage, the second supply passage extending in the radial direction The cooling gas may have a second radial passage formed across the spindle body and the spindle in the radial direction so as to include a portion of a second gap between the spindle body and the spindle, the second radial passage having a first rear-side passage formed in the spindle body and a second rear-side passage formed in the spindle through which the cooling gas flows from the first rear-side passage, and a pair of second axial gaps located on both sides of the second radial passage in the axial direction within the second gap may function as second throttles to reduce leakage of the cooling gas from the second radial passage. According to this aspect, the second radial passage formed across the spindle body and the spindle in the radial direction allows cooling gas to be supplied from the spindle body to a second cooling passage formed on the outer peripheral surface of the spindle, thereby preventing the passage configuration for cooling the second rolling bearing from becoming complicated. Furthermore, the second rolling bearing covers the second cooling passage, allowing the second rolling bearing to be directly cooled by the cooling gas flowing through the second cooling passage. (8) In the above aspect, due to the function as the second throttle, a relationship may be established in which the flow rate of the cooling gas flowing from the first rear-side passage into the second rear-side passage is greater than a flow rate of the cooling gas leaking from the second front-side passage into the pair of second axial gaps. According to this aspect, a larger flow rate of the cooling gas is supplied to the second cooling passage, thereby enabling efficient cooling of the second rolling bearing. (9) In the above aspect, the cooling system may further include an encoder for detecting information related to the rotation of the main shaft, a bearing stopper positioned rearward of the second rolling bearing and restricting the axial movement of the second rolling bearing, and a second exhaust passage for exhausting the cooling gas flowing out of the second cooling passage to the outside, the encoder having a ring-shaped member attached to the outer circumferential surface of the bearing stopper and moving in conjunction with the rotation of the main shaft, the second exhaust passage having a second upstream exhaust passage connected to the second cooling passage and formed in the main shaft, and a second downstream exhaust passage through which the cooling gas flowing out of the second upstream exhaust passage flows and formed in the bearing stopper, a downstream outlet of the second downstream exhaust passage being formed on the outer circumferential surface of the bearing stopper rearward of the ring-shaped member. According to this aspect, the cooling gas injected from the downstream outlet forms a gas wall by a gas flow, thereby preventing foreign matter such as dust from adhering to the ring-shaped member. (10) In the above aspect, the pair of second axial gaps may be located between the second rolling bearing and the rotation drive motor in the axial direction. According to this aspect, it is possible to prevent the cooling gas flowing out from the first upstream discharge passage from leaking to the second rolling bearing through the second axial gaps. The present disclosure can be realized in various forms, and in addition to the spindle device described above, can be realized in the form of, for example, a method for manufacturing a spindle device, a method for controlling a spindle device, etc. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic diagram showing a vertical cross section of the spindle device according to the embodiment. [Figure 2] Cross-sectional view of the spindle device. [Figure 3] FIG. 4 is a diagram illustrating a first air flow path. [Figure 4] FIG. 4 is a cross-sectional view of the spindle device near a second rolling bearing. [Figure 5] FIG. 4 is a diagram illustrating a second air flow path. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. Implementation: FIG. 1 is a schematic diagram showing a vertical cross section of a spindle unit 1 according to an embodiment. The spindle unit 1 according to this embodiment is a motor-built-in type spindle unit provided in a machine tool such as a horizontal machining center. The spindle unit 1 grips a tool (shown) for machining a workpiece on its front side. FIG. 1 shows an axis AX of a spindle 10 of the spindle unit 1. The upper half of the drawing above the axis AX shows an unclamped state in which the tool is released from gripping, and the lower half of the drawing below the axis AX shows a clamped state in which the tool is gripped. In addition, in the axial direction along the axis AX, the side gripping the tool is the front side, and the side opposite the side gripping the tool is the rear side. In addition, the upper side of the page in FIG. 1 corresponds to the vertically upward side, and the lower side of the page corresponds to the vertically downward side.

[0009] The spindle device 1 includes a cylindrical spindle device main body 3, a spindle 10, a plurality of first rolling bearings 10A, a plurality of second rolling bearings 10B, a rotation drive motor 40, a push rod 30, a collet 32, a disc spring 33, a movement control mechanism 15, and a control device 90. The spindle device main body 3 is a housing that houses the main elements of the spindle device 1, such as the spindle 10 and the rotation drive motor 40, inside.

[0010] The spindle 10 is rotatably supported on the spindle body 3 via a plurality of first rolling bearings 10A and a plurality of second rolling bearings 10B. The spindle 10 has an axis AX and rotates about the axis AX when driven by a rotary drive motor 40. The spindle 10 has a front end 10F located on the front side and a rear end 10R facing the front end 10F and located on the rear side. The spindle 10 also has a spindle bore 10H that penetrates in the axial direction. A tool hole 10T is formed in the spindle bore 10H on the front end 10F side, and a tool is placed in the tool bore 10T for mounting the tool on the spindle 1.

[0011] In this embodiment, the number of first rolling bearings 10A is two. In addition, the number of second rolling bearings 10B is two. The first rolling bearings 10A and the second rolling bearings 10B are angular rolling bearings. The two first rolling bearings 10A are disposed axially forward of the rotation drive motor 40. The two first rolling bearings 10A are disposed side by side in the axial direction. Bearing holders 17 and 18 that restrict axial movement are disposed in front of and behind the inner rings 11A of the two first rolling bearings 10A. A spindle cap 10S is disposed in front of the bearing holder 17, and a step portion 10D of the main shaft 10 is formed behind the bearing holder 18. By fixing the spindle cap 10S to the main shaft 10, the two first rolling bearings 10A and bearing holders 17, 18 are axially sandwiched between the spindle cap 10S and a stepped portion 10D. The stepped portion 10D can be formed by a large-diameter portion 10p, which will be described later. A front cover 10C and a stepped portion 10E are disposed in front and behind the outer rings 13A of the two first rolling bearings 10A to restrict axial movement. The front cover 10C is fixed to the main body portion 3a with bolts, and the stepped portion 10E is formed on the main body portion 3a. The first rolling bearing 10A is interposed between the main spindle body 3 and the main shaft 10 in the radial direction of the main shaft 10, which is perpendicular to the axial direction. The second rolling bearing 10B is disposed axially rearward of the first rolling bearing 10A, specifically, rearward of the rotation drive motor 40. The two second rolling bearings 10B are disposed side by side in the axial direction. The second rolling bearing 10B is interposed between the spindle device main body 3 and the spindle 10 in the radial direction of the spindle 10. The first rolling bearing 10A and the second rolling bearing 10B each have inner rings 11A and 11B, outer rings 13A and 13B, and multiple rolling elements 12A and 12B arranged between the raceways of the inner rings 11A and 11B and the outer rings 13A and 13B. The multiple rolling elements 12A and 12B are held at equal intervals along the circumferential direction by a cage (not shown). The inner rings 11A and 11B are fitted onto the outer peripheral surface 10fa of the spindle 10. The first rolling bearing 10A and the second rolling bearing 10B are each lubricated with grease. In other words, grease is applied to the raceways of the inner rings 11A and 11B and the outer rings 13A and 13B and the rolling elements 12.

[0012] The rotary drive motor 40 is a direct drive motor that rotates the spindle 10. The rotary drive motor 40 includes a rotor 41 and a stator 42. The rotary drive motor 40 is disposed on the outer peripheral side of the spindle 10 inside the spindle device main body 3. The rotor 41 is configured to be rotatable integrally with the spindle 10 via a rotor sleeve 49. The rotor 41 rotates when power is supplied to the stator 42 under the control of the control device 90. The rotation of the rotor 41 rotates the spindle 10. The rotary drive motor 40 is provided in an arrangement chamber 98, which is a space located between the outer peripheral surface 10fa of the spindle 10 and the inner peripheral surface 3fa of the spindle device main body 3.

[0013] Push rod 30 is disposed in spindle bore 10H within spindle 10. Push rod 30 has one end 30F located on the front end 10F side and the other end 30R located on the rear end 10R side. Push rod 30 is movable along the axial direction of spindle 10 by operation of movement control mechanism 15. Push rod 30 is coupled to spindle 10 so as to move in conjunction with the rotational movement of spindle 10.

[0014] The collet 32 ​​is attached to one end 30F of the push rod 30. The collet 32 ​​moves in conjunction with the push rod 30 and assumes one of two states: a clamped state in which the tool is gripped, and an unclamped state in which the grip of the tool is released. Specifically, the collet 32 ​​is in the unclamped state when the push rod 30 is pushed forward by the movement control mechanism 15 and moves toward the one end 30F. On the other hand, the collet 32 ​​is in the clamped state when the push rod 30 moves away from the movement control mechanism 15 and toward the other end 30R due to the biasing force of the disc spring 33.

[0015] The disc spring 33 is disposed in the spindle bore 10H within the spindle 10, between the inner peripheral surface of the spindle 10 and the push rod 30. The disc spring 33 is disposed axially between a collar 34 disposed on the inner peripheral side of the spindle 10 and a large-diameter portion 30D formed on the other end 30R of the push rod 30. Specifically, the disc spring 33 is inserted through the outer peripheral portion of the push rod 30. A plurality of disc springs 33 are provided along the axial direction. The rear end of each disc spring 33 abuts against the large-diameter portion 30D of the push rod 30 in a state facing the axial direction. This causes the disc spring 33 to apply a biasing force to the push rod 30 from the front end 10F toward the rear end 10R. This biasing force keeps the collet 32 ​​in a clamped state when the movement control mechanism 15 is not operating.

[0016] The movement control mechanism 15 is disposed axially rearward of the push rod 30. The movement control mechanism 15 has a piston 18 configured to be movable in the axial direction. The piston 18 faces the other end 30R of the push rod 30 in the axial direction. When the piston 18 moves forward, the push rod 30 is moved forward by the piston 18 against the biasing force of the disc spring 33. This places the collet 32 ​​in an unclamped state.

[0017] The control device 90 is configured with a CPU, a storage device, etc., and controls the operation of the spindle device 1. For example, the control device 90 controls the operation of the rotation drive motor 40 of the spindle device 1.

[0018] The spindle device 1 further includes a cooling gas supply device 91, an air supply device 92, a hydraulic device 93, a coolant supply device 95, and a cooling liquid supply device 96. The operations of these devices 91, 92, 93, 95, and 96 are controlled by a control device 90.

[0019] The cooling gas supply device 91 supplies temperature-regulated cooling gas at a predetermined flow rate per minute to cool the inner rings 11A and 11B of the first rolling bearing 10A and the second rolling bearing 10B, respectively. In this embodiment, the cooling gas supply device 91 supplies cooling gas toward each of the tip ends 81a and 81b. Various gases, such as air, nitrogen, and carbon dioxide, can be used as the cooling gas. In this embodiment, air is used as the cooling gas. The cooling gas supply device 91 is, for example, an air temperature control device equipped with a compressor, and can arbitrarily set the air temperature and air supply amount. In response to a command from the control device 90, the cooling gas supply device 91 supplies air at least during the rotation of the spindle 10. The cooling gas supply device 91 supplies air into the spindle main body 3 through the tip ends 81a and 81b of pipes attached to the spindle main body 3. The flow path of the air supplied from the tip end 81a into the spindle body 3 will be described in detail later, but the outline is as follows. That is, the air supplied into the spindle body 3 flows through the first cooling gas flow path 20 to cool the inner ring 11A of the first rolling bearing 10A. The first cooling gas flow path 20 has a mounting chamber 98 in its middle. The air flowing through the mounting chamber 98 cools the rotation drive motor 40. The first cooling gas flow path 20 also has a through hole 20d formed in the bearing housing 14 as an air outlet. The bearing housing 14 is a component of the spindle body 3. The through hole 20d connects the mounting chamber 98 with the outside. The air flowing through the mounting chamber 98 is discharged to the outside from the through hole 20d. The through hole 20d is also used as a path for a wire connecting the rotation drive motor 40 and the control device 90.

[0020] The flow path of the air supplied from tip end 81b into spindle body 3 will be described in detail later, but the outline is as follows: That is, the air supplied into spindle body 3, more specifically into bearing housing 14, flows through second cooling gas flow path 26 and cools inner ring 11B of second rolling bearing 10B.

[0021] The air supply device 92 is, for example, a compressor, and sends pressurized air to a flow path provided in the piston 18 of the movement control mechanism 15. This flow path provided in the piston 18 constitutes a part of the air purge flow path 120. The air supplied by the air supply device 92 flows through the air purge flow path 120 and is sprayed onto the tool bore 10T located on the front side. This removes chips adhering to the tool bore 10T. The hydraulic device 93 supplies and discharges hydraulic oil to and from the cylinder chamber 18a to move the piston 18 along the axial direction. When the hydraulic device 93 moves the piston 18 forward to push the push rod 30 forward (to achieve the unclamped state), it supplies hydraulic oil to a first port 83 of the cylinder chamber 18a. On the other hand, when the hydraulic device 93 moves the piston 18 rearward to separate it from the push rod 30 (to achieve the clamped state), it supplies hydraulic oil to a second port 84 of the cylinder chamber 18a. The coolant supply device 95 supplies coolant to a coolant passage 130 extending in the axial direction through an opening 185 on the rear end side of the movement control mechanism 15. The coolant flows through the coolant passage 130, passes through one end 30F and the inside of the tool, and is supplied to the cutting point, which is the cutting edge of the tool.

[0022] The coolant supply device 96 supplies coolant to the outer rings 13A and 13B of the first rolling bearing 10A and the second rolling bearing 10B, respectively, and the stator 42 of the rotation drive motor 40. The coolant supply device 96 supplies cooling water as a coolant at least during the rotation of the spindle 10 in response to a command from the control device 90. The coolant supply device 96 supplies temperature-adjusted cooling water at a predetermined flow rate per minute. The coolant supply device 95 includes a tank and a pump, and may further include a heat exchanger such as a radiator. The coolant supply device 96 supplies coolant to a first flow path 85, a second flow path 87, and a third flow path 88 formed in the spindle main body 3 via a circulation pipe 97 that circulates the coolant. The first flow path 85, the second flow path 87, and the third flow path 88 are connected in parallel by the circulation pipe 97 and flow paths formed in the spindle main body 3. The first flow path 85, the second flow path 87, and the third flow path 88 will be described in detail below.

[0023] Next, we will explain the configuration related to the various flow paths of the spindle unit 1. Note that the criteria for "upstream" and "downstream" for the various flow paths are based on the flow direction of the fluid supplied from each device 91, 92, 93, 95, and 96 (Fig. 1). The spindle unit 1 has a coolant flow path 130 that supplies coolant to a machining point that is machined by a tool held by the collet 32, and an air purge flow path 120 that supplies air to be blown into the tool hole 10T to the tool hole 10T.

[0024] The coolant passage 130 includes a first coolant passage 19 formed in the movement control mechanism 15, a fourth coolant passage 47a formed in the fixed joint 47, a second coolant passage 48 formed in the rotary joint 46, and a third coolant passage 38 formed in the push rod 30. Coolant supplied from the coolant supply device 95 flows through the first coolant passage 19, the fourth coolant passage 47a, the second coolant passage 48, and the third coolant passage 38 in this order. The coolant then passes through one end 30F of the push rod 30 and inside the tool, and is supplied to the cutting point, which is the cutting edge of the tool. The cutting point is located on the front end 10F side. Thus, the coolant passage 130 is a passage formed along the axial direction. In response to a command from the control device 90, the coolant supply device 95 supplies coolant to the coolant passage 130 while the spindle 10 is rotating in the clamped state.

[0025] The air purge passage 120 includes a first air purge passage 55 formed in the piston 18, a second air purge passage 35 formed in the push rod 30, a third air purge passage 126 formed between the main shaft 10 and the push rod 30, and fourth and fifth air purge passages 155 and 156 formed within the main shaft 10. When the end faces of the piston 18 and the push rod 30 abut against each other in the unclamped state, the first air purge passage 55 of the piston 18 is connected to the second air purge passage 35 of the push rod 30. The second air purge passage 35 is formed by a gap between the inner circumferential surface of the outer push rod (not shown) and the outer circumferential surface of the inner push rod (not shown) of the push rod 30. As shown in FIG. 1 , the third air purge passage 126 allows air that has circulated through the second air purge passage 35 to flow. The third air purge passage 126 is formed by a gap between the main shaft 10 and the push rod 30. A plurality of fourth air purge passages 155 are formed at intervals around axis AX within front end 10F of spindle 10. The upstream end of fourth air purge passage 155 is connected to third air purge passage 126, and the downstream end of fourth air purge passage 155 is in communication with fifth air purge passage 156, the downstream end of which opens toward tool bore 10T. Air passes through fourth air purge passage 155 and is then blown from fifth air purge passage 156 into tool bore 10T. In response to a command from control device 90, air supply device 92 supplies pressurized air to air purge passage 120 when push rod 30 has been moved forward by piston 18, thereby entering an unclamped state.

[0026] The first flow path 85 is formed in the spindle body 3 in the axial direction, on the outer diameter side of the first rolling bearing 10A, in an area where the first rolling bearing 10A is located. The first flow path 85 is formed by a spiral groove formed in the outer peripheral surface of the main body 3a and an annular first cover member 3b that covers the groove. The main body 3a and the first cover member 3b constitute the spindle body 3. The outer ring 13A of the first rolling bearing 10A is cooled by the coolant flowing through the first flow path 85.

[0027] The second flow path 87 is formed on the outer diameter side of the stator 42 in an area of ​​the spindle body 3 in the axial direction where the rotation drive motor 40 is located. The second flow path 87 is formed by a spiral groove formed on the outer peripheral surface of the main body 3a and an annular second cover member 3c that covers the groove. The second cover member 3c constitutes the spindle body 3. The rotation drive motor 40 is cooled by the coolant flowing through the second flow path 87.

[0028] The third flow path 88 is formed in the bearing housing 14 in the axial direction, in a region where the second rolling bearing 10B is located, on the outer diameter side of the second rolling bearing 10B. The third flow path 88 is formed by a spiral groove formed in the outer peripheral surface of the housing main body 14a and an annular third cover member 14b that covers the groove. The housing main body 14a and the third cover member 14b constitute the bearing housing 14. The bearing housing 14 is attached to the rear end of the main body 3a and constitutes the spindle main body 3. The outer ring 13B of the second rolling bearing 10B is cooled by the coolant flowing through the third flow path 88.

[0029] Fig. 2 is a cross-sectional view of spindle device 1. Fig. 3 is a diagram for explaining first cooling gas flow path 20. Components such as push rod 30 and collet 32 ​​arranged in spindle 10 are omitted from Fig. 2. Fig. 3 is an enlarged view of the vicinity of first radial flow path 22 in first cooling gas flow path 20. Details of first cooling gas flow path 20 will be described using Figs. 2 and 3.

[0030] As shown in FIG. 2, first cooling gas flow path 20 includes, in order from upstream to downstream, first supply flow path 20a, first cooling flow path 20b, and first discharge flow path 20c. First supply flow path 20a has a tip end 81a, which is its upstream end, and a downstream end 21 connected to first cooling flow path 20b. First supply flow path 20a is a hole formed in spindle body 3 and spindle 10. First supply flow path 20a supplies air to first cooling flow path 20b for cooling inner ring 11A of first rolling bearing 10A. First supply flow path 20a includes first main body flow path 20a1 formed in spindle body 3 and first spindle flow path 20a2 formed in spindle 3. As shown in FIG. 3, a downstream portion of first main body flow path 20a1 and an upstream portion of first spindle flow path 20a2 form first radial flow path 22 extending radially. As shown in FIG. 3, the first radial flow passage 22 is a flow passage formed across the spindle device main body 3 and the spindle 10 in the radial direction.

[0031] As shown in FIG. 3, the first radial flow passage 22 includes, in order from upstream to downstream, a first front-side flow passage 22a, a first inlet opening 22c as an inlet opening, and a second front-side flow passage 22b. The first front-side flow passage 22a is a downstream portion of the first main body flow passage 20a1 formed in the spindle main body 3. The first inlet opening 22c and the second front-side flow passage 22b are formed in the large-diameter portion 10p of the spindle 10 and receive air flowing out from the first front-side flow passage 22a. The first inlet opening 22c is defined by a groove 25 formed circumferentially on the outer peripheral surface 10fa of the large-diameter portion 10p of the spindle 10. That is, the portion of the groove 25 formed circumferentially that is connected to the second front-side flow passage 22b in the radial direction is the first inlet opening 22c. The groove 25 is formed at a position radially opposite the downstream end 22d of the first front-side flow passage 22a. First inlet opening 22c and second front-side flow passage 22b constitute upstream portions of first main spindle flow passage 20a2. In this embodiment, there is only one second front-side flow passage 22b. However, in other embodiments, multiple second front-side flow passages 22b may be formed at different positions in the circumferential direction of main spindle 10. When multiple second front-side flow passages 22b are formed, the downstream ends of the multiple second front-side flow passages 22b may merge. As described above, first inlet opening 22c is defined by groove 25 formed circumferentially on outer peripheral surface 10fa of main spindle 10. This allows air from first front-side flow passage 22a to efficiently flow into second front-side flow passage 22b via groove 25, even when first front-side flow passage 22a and second front-side flow passage 22b are not aligned radially. In other words, air from first front-side flow passage 22a can flow into second front-side flow passage 22b via groove 25, even during rotation of main spindle 10.

[0032] The flow path cross-sectional area of ​​the first inlet opening 22c is larger than the flow path cross-sectional area of ​​the first front-side flow path 22a and the flow path cross-sectional area of ​​the second front-side flow path 22b. This allows a larger amount of air from the first front-side flow path 22a to flow into the first inlet opening 22c. A first gap GP1 is provided between the outer peripheral surface 10fa of the spindle 10 (specifically, the large diameter portion 10p) and the inner peripheral surface 3fa of the spindle main body 3 to prevent collision between the spindle main body 3 and the rotating spindle 10. The first radial flow path 22 is formed to include a part of this first gap GP1 (specifically, a first flow path forming gap GP1a described later). In other words, the first front-side flow path 22a and the second front-side flow path 22b communicate with each other via the first gap GP1. The flow path resistance of the first gap GP1 is set to be sufficiently larger than the flow path resistance of the first radial flow path 22 to an extent that the air in the first front-side flow path 22a can flow in the axial direction through the first gap GP1 and can be minimized from leaking out of the first radial flow path 22. In this embodiment, the radial dimension of the first gap GP1 is set to 20 μm or more and 70 μm or less, preferably 20 μm or more and 30 μm or less, so that the first gap GP1 can have a sealing function in the axial direction while suppressing collision between the spindle device main body 3 and the spindle 10.

[0033] As shown in FIG. 3 , the first gap GP1 includes a first flow passage forming gap GP1a that constitutes the first radial flow passage 22, and a pair of first axial gaps GP1b and GP1c located on both sides of the first radial flow passage 22 in the axial direction. The pair of first axial gaps GP1b and GP1c are located on both sides of the first flow passage forming gap GP1a in the axial direction and function as first throttles that reduce leakage of air, which is cooling gas, from the first radial flow passage 22. In this embodiment, the radial dimensions of the first gap GP1 and the pair of first axial gaps GP1b and GP1c are the same. Note that the predetermined flow rate of air supplied to the first cooling flow passage 20b can be achieved by changing the flow rate of air supplied to the first supply flow passage 20a, the radial dimension of the first gap GP1, or the axial dimension of the first gap GP1.

[0034] As shown in FIG. 2, first cooling flow channel 20b is a spiral flow channel formed as a groove in outer peripheral surface 10fa of main shaft 10. The flow space of first cooling flow channel 20b is defined by the spiral groove formed in outer peripheral surface 10fa of main shaft 10 and a member covering the groove. The member covering the groove is, for example, inner ring 11A of first rolling bearing 10A or bearing retainer 17. In other words, if the region in the axial direction of main shaft 10 where first rolling bearing 10A is arranged is defined as first region R10A, first cooling flow channel 20b is covered by inner ring 11A of first rolling bearing 10A in first region R10A. As a result, inner ring 11A of first rolling bearing 10A comes into direct contact with the cooling gas flowing through first cooling flow channel 20b. First cooling flow passage 20b is formed on the inner diameter side of first rolling bearing 10A in at least region R10A where first rolling bearing 10A is disposed, in the axial direction of main shaft 10. Inner ring 11A of first rolling bearing 10A is directly cooled by air flowing through first cooling flow passage 20b. In this way, inner ring 11A is cooled directly by first cooling flow passage 20b without passing through other members, and therefore heat is more easily transferred to inner ring 11A than when cooling is performed via other members.

[0035] The first exhaust flow path 20c is a flow path that exhausts air flowing out from the first cooling flow path 20b to the outside. The first exhaust flow path 20c has, in order from upstream to downstream, a first upstream exhaust flow path 20c1, an arrangement chamber 98, and a first downstream exhaust flow path 20c2. The first upstream exhaust flow path 20c1 is connected to the first cooling flow path 20b and allows air flowing out from the first cooling flow path 20b to flow into the arrangement chamber 98. The first upstream exhaust flow path 20c1 has a first upstream first exhaust flow path 20c3 formed in the radial direction and communicating with the first cooling flow path 20b, a first upstream second exhaust flow path 20c4 formed in the axial direction and communicating with the first upstream first exhaust flow path 20c3, and a first upstream third exhaust flow path 20c5 formed in the radial direction and communicating with the first upstream second exhaust flow path 20c4. The first upstream-side third discharge flow path 20c5 forms the downstream end 20c6 of the first upstream-side discharge flow path 20c1, which discharges air into the arrangement chamber 98. The first upstream-side third discharge flow path 20c5 is formed in the medium diameter portion 10q of the main shaft 10. Because the outer diameter of the medium diameter portion 10q is approximately the same as the outer diameter of the rotor 41, the downstream end 20c6 and the gap between the stator 42 and the rotor 41 are located at approximately the same position in the radial direction. Therefore, air that has discharged from the downstream end 20c6 into the arrangement chamber 98 can easily flow into the gap between the stator 42 and the rotor 41. In addition, the downstream end 20c6 of the first upstream-side discharge flow path 20c1 is located axially between the rotation drive motor 40 and one of the pair of first axial gaps GP1b, GP1c, which is the rearmost first axial gap GP1c. As a result, the pair of first axial gaps GP1b, GP1c function as first throttles, preventing the cooling gas flowing out from the first upstream exhaust passage from leaking to the first rolling bearing 10A via the pair of first axial gaps GP1b, GP1c. This allows a larger flow rate of cooling gas to be used to efficiently cool the rotation drive motor 40. The medium-diameter portion 10q has a smaller outer diameter than the large-diameter portion 10p and is located axially between the large-diameter portion 10p and the rotation drive motor 40. The first upstream-side first exhaust passage 20c3, the first upstream-side second exhaust passage 20c4, and the first upstream-side third exhaust passage 20c5 are holes formed in the main shaft 10.The first upstream first discharge flow path 20c3, the first upstream second discharge flow path 20c4, and the first upstream third discharge flow path 20c5 are formed in the single member, i.e., the spindle 10, resulting in less air leakage than when formed in two members. The downstream end of the first upstream third discharge flow path 20c5 opens into the mounting chamber 98 at a position in the axial direction that is forward of the rotation drive motor 40 within the mounting chamber 98 and on the outer periphery of the medium-diameter portion 10q. Air flowing out of the first upstream discharge flow path 20c1 flows into the mounting chamber 98. The air in the mounting chamber 98 cools the rotation drive motor 40 by circulating between the rotor 41 and the stator 42. The first downstream discharge flow path 20c2 is a hole formed in the spindle main body 3, specifically the bearing housing 14, which defines the mounting chamber 98. The first downstream discharge flow path 20c2 is located axially rearward of the rotation drive motor 40. The first downstream discharge flow path 20c2 discharges air in the arrangement chamber 98 to the outside of the spindle device main body 3. Because of the presence of the large diameter portion 10p and the medium diameter portion 10q, the spindle 10 is inserted from the rear side of the main body 3a, not from the front side of the main body 3a.

[0036] FIG. 4 is a cross-sectional view of the spindle unit 1 near the second rolling bearing 10B. Referring to FIG. 4, components located around the second cooling gas passage 26 and the second rolling bearing 10B will be described. The spindle unit 1 further includes an encoder 45, bearing holders 16a and 16b, a rotary joint 44, and a nut 43. The encoder 45 detects information related to the rotation of the spindle 10, such as the rotational angle position and rotational speed of the spindle 10, and transmits a detection signal to the control device 90. The encoder 45 may be optical or magnetic. When the encoder 45 is magnetic, the encoder 45 includes a magnetic ring 45a attached to the outer circumferential surface 16fa of the bearing holder 16a, which serves as a ring-shaped member interlocked with the rotation of the spindle 10, and a sensor 46b that outputs a detection signal to the magnetic ring 45a in response to changes in the magnetic field corresponding to the rotation.

[0033] Note that if encoder 45 is optical, a disk with slits formed therein is used as the ring-shaped member instead of magnetic ring 45a, and an optical sensor is used as sensor 46b. Bearing holder 16a is threadedly connected to the outer periphery of main shaft 10. Bearing holder 16b is located on the front side of inner ring 11B of second rolling bearing 10B and abuts against step 10G of main shaft 10. Bearing holder 16a is located on the rear side of inner ring 11B of second rolling bearing 10B and abuts against the end face of inner ring 11B of second rolling bearing 10B, and together with step 10G, restricts axial movement of inner ring 11B of second rolling bearing 10B. The step portion of the housing body 14a is located in front of the outer rings 13B of the two second rolling bearings 10B, and the bearing holder 14e is located behind them, so that the outer rings 13B of the two second rolling bearings 10B are axially sandwiched between the step portion 14c and the bearing holder 14e. The step portion 14c is formed on the housing body 14a, and the bearing holder 14e is threadedly connected to the inner periphery of the housing body 14a. The rotary joint 44 has a rotary joint 46 (FIG. 1) attached to the rear end of the spindle 10 and a fixed joint 47 (FIG. 1) attached to the movement control mechanism 15. The rotary joint 46 and the fixed joint 47 are in sliding contact with each other at their end surfaces. The rotary joint 46 and the fixed joint 47 have flow paths through which coolant supplied from a coolant supply device 95 (FIG. 1) flows. The nut 43 is disposed between the bearing holder 16a and the main shaft 10, and locks the bearing holder 16a to prevent it from loosening.

[0037] Next, second cooling gas flow path 26 will be described with reference to FIG. 5 in addition to FIG. 4. FIG. 5 is a diagram for explaining second cooling gas flow path 26. As shown in FIG. 4, second cooling gas flow path 26 includes, in order from upstream to downstream, second supply flow path 26a, second cooling flow path 26b, and second discharge flow path 26c. Second supply flow path 26a has tip end 81b, which is its upstream end, and downstream end 28 connected to second cooling flow path 26b. Second supply flow path 26a has second main body flow path 26a1 formed in housing main body 14a and second spindle flow path 26a2 formed in spindle 10. Second main body flow path 26a1 is a hole formed in housing main body 14a, which is a component of spindle unit main body 3. Second spindle flow path 26a2 is a hole formed in spindle 10, which is a component of spindle unit 1. Because second main body flow passage 26a1 is formed in one member, housing main body 14a, there is less air leakage than if it were formed in two members. Second supply flow passage 26a supplies air to second cooling flow passage 26b for cooling inner ring 11B of second rolling bearing 10B. As shown in FIG. 5, the downstream portion of second main body flow passage 26a1 and the upstream portion of second main shaft flow passage 26a2 form second radial flow passage 122 extending radially. Second radial flow passage 122 is a flow passage formed spanning between bearing housing 14 and main shaft 10 in the radial direction.

[0038] As shown in FIG. 5, second radial flow passage 122 includes, in order from upstream to downstream, first rear-side flow passage 122a, second inlet opening 122c, and second rear-side flow passage 122b. First rear-side flow passage 122a is the downstream portion of second main body flow passage 26a1 formed in bearing housing 14. Second inlet opening 122c is formed in outer peripheral surface 10fa of main shaft 10 and receives air flowing out from first rear-side flow passage 122a. Second inlet opening 122c is defined by a groove 125 formed circumferentially in outer peripheral surface 10fa of main shaft 10. That is, the portion of groove 125 formed circumferentially that is connected to second rear-side flow passage 122b in the radial direction constitutes second inlet opening 122c. Groove 125 is formed at a position radially opposite downstream end 122d of first rear-side flow passage 122a. The second inlet opening 122c and the second rear-side flow passage 122b constitute the upstream portion of the second main spindle flow passage 26a2. In this embodiment, there is only one second rear-side flow passage 122b. However, in other embodiments, multiple second rear-side flow passages 122b may be formed at different positions in the circumferential direction of the main spindle 10. When multiple second rear-side flow passages 122b are formed, the downstream ends of the multiple second rear-side flow passages 122b may merge. As described above, the second inlet opening 122c is defined by a groove 125 formed circumferentially on the outer circumferential surface 10fa of the main spindle 10. This allows air from the first rear-side flow passage 122a to efficiently flow into the second rear-side flow passage 122b via the groove 125, even when the first rear-side flow passage 122a and the second rear-side flow passage 122b are not aligned radially. In other words, air from the first rear-side flow passage 122a can flow into the second rear-side flow passage 122b via the groove 125, even during rotation of the main spindle 10.

[0039] The flow path cross-sectional area of ​​the second inlet opening 122c is larger than the flow path cross-sectional area of ​​the second rear-side flow path 122b. This allows a larger amount of air from the first rear-side flow path 122a to flow into the second inlet opening 122c. Here, a second gap GP2 is provided between the outer peripheral surface 10fa of the spindle 10 and the spindle unit main body 3, specifically, the inner peripheral surface 14fa of the bearing housing 14, to prevent collision between the spindle unit main body 3 and the rotating spindle 10. The second radial flow path 122 is formed to include a part of this second gap GP2 (more specifically, a second flow path forming gap GP2a described later) in the middle. In other words, the first rear-side flow path 122a and the second rear-side flow path 122b communicate with each other via the second gap GP2. The flow path resistance of the second gap GP2 is set to be sufficiently larger than the flow path resistance of the second radial flow path 122 to an extent that the air in the first rear-side flow path 122a can flow in the axial direction through the second gap GP2 and can be minimized from leaking out of the second radial flow path 122. In this embodiment, the dimension of the second gap GP2 in the radial direction is set to 20 μm or more and 70 μm or less, preferably 20 μm or more and 30 μm or less, thereby allowing the second gap GP2 to have a sealing function in the axial direction while suppressing collision between the spindle device main body 3 and the spindle 10.

[0040] As shown in FIG. 5, the second gap GP2 includes a second flow passage forming gap GP2a that constitutes the second radial flow passage 122, and a pair of second axial gaps GP2b and GP2c located on both sides of the second radial flow passage 122 in the axial direction. The pair of second axial gaps GP2b and GP2c are located on both sides of the second flow passage forming gap GP2a in the axial direction and function as second throttles that reduce leakage of air, which is cooling gas, from the second radial flow passage 122. In this embodiment, the second gap GP2 and the pair of second axial gaps GP2b and GP2c have the same radial dimension. The predetermined flow rate of air supplied to the second cooling flow passage 26b can be achieved by changing the flow rate of air supplied to the second supply flow passage 26a, the radial dimension of the second gap GP2, or the axial dimension of the second gap GP2. 1 and 5, the pair of second axial gaps GP2b, GP2c are located axially between the second rolling bearing 10B and the rotation drive motor 40. In this way, the pair of second axial gaps GP2b, GP2c function as a second throttle, and therefore, the cooling gas flowing out from the first upstream discharge flow passage 20c1 can be prevented from leaking to the second rolling bearing 10B via the second axial gaps GP2b, GP2c.

[0041] As shown in FIG. 4, second cooling flow channel 26b is a spiral flow channel formed as a groove in outer peripheral surface 10fa of main shaft 10. The flow space of second cooling flow channel 26b is defined by the spiral groove formed in outer peripheral surface 10fa of main shaft 10 and a member covering the groove. The member covering the groove is, for example, inner ring 11B of second rolling bearing 10B. In other words, if the region in the axial direction of main shaft 10 where second rolling bearing 10B is arranged is defined as second region R10B, second cooling flow channel 26b is covered by inner ring 11B of second rolling bearing 10B in second region R10B. As a result, inner ring 11B of second rolling bearing 10B comes into direct contact with the cooling gas flowing through second cooling flow channel 26b. Second cooling flow passage 26b is formed on the inner diameter side of second rolling bearing 10B in at least region R10B where second rolling bearing 10B is disposed, in the axial direction of main shaft 10. Inner ring 11B of second rolling bearing 10B is directly cooled by air flowing through second cooling flow passage 26b. In this way, inner ring 11B is cooled directly by second cooling flow passage 26b without passing through other members, so heat is more easily transferred to inner ring 11B than when cooling is performed via other members.

[0042] The second exhaust flow path 26c is a flow path that discharges air flowing out from the second cooling flow path 26b to the outside. The second exhaust flow path 26c is a hole formed in the main shaft 10 and the bearing holder 16a. The second exhaust flow path 26c has a second upstream exhaust flow path 26c1 connected to the second cooling flow path 26b and a second downstream exhaust flow path 26c2 through which air flowing out from the second upstream exhaust flow path 26c1 flows. The second upstream exhaust flow path 26c1 is a hole formed in the main shaft 10. The second downstream exhaust flow path 26c2 is a hole formed in the bearing holder 16a. In other words, the second exhaust flow path 26c is formed in two components, the main shaft 10 and the bearing holder 16a, and air leaks from between the two components. However, because the second exhaust flow path 26c is formed on the exhaust side of the second cooling flow path 26b, a flow rate sufficient to cool the inner ring 11B can be supplied to the second cooling flow path 26b. The downstream outlet 26c3 of the second downstream discharge flow path 26c2 is formed on the outer peripheral surface 16fa of the bearing holder 16a, rearward of the magnetic ring 45a, which is a ring-shaped member. This positions the downstream outlet 26c3 near the magnetic ring 45a. The downstream outlet 26c3 injects air into the space between the outer peripheral surface 16fa and the inner peripheral surface of the bearing housing 14. The air injected radially from the downstream outlet 26c3 forms a gas wall (air curtain) with the gas flow, thereby preventing foreign matter such as dust from adhering to the magnetic ring 45a. As shown in FIG. 1, the second cooling gas flow path 26 further includes a through hole 26d formed in the bearing housing 14 as an air outlet. The through hole 26d connects the space between the outer peripheral surface 16fa and the inner peripheral surface of the bearing housing 14 to the outside. The air injected radially from the downstream outlet 26c3 is discharged to the outside through the through hole 26d.

[0043] According to the above embodiment, as shown in Fig. 2 and Fig. 3, first radial flow passage 22 formed radially across spindle body 3 and spindle 10 can supply air from spindle body 3 to first cooling flow passage 20b formed on outer peripheral surface 10fa of spindle 10. Furthermore, according to the above embodiment, as shown in Fig. 4 and Fig. 5, second radial flow passage 122 formed radially across spindle body 3 and spindle 10 can supply air from spindle body 3 to second cooling flow passage 26b formed on outer peripheral surface 10fa of spindle 10. This eliminates the need to form flow passages for cooling inner rings 11A, 11B in push rod 30 disposed in the axial hole of spindle 10, thereby preventing the flow passage configurations of first cooling gas flow passage 20 and second cooling gas flow passage 26 from becoming complicated. Furthermore, the first cooling flow path 20b and the second cooling flow path 26b allow the inner rings 11A and 11B, which are the main heat sources of the first rolling bearing 10A and the second rolling bearing 10B, to be directly cooled with air. This prevents the temperature of the grease applied to the first rolling bearing 10A and the second rolling bearing 10B for lubrication from becoming too high, thereby suppressing grease degradation. In other words, the time until the grease performance deteriorates and reaches the end of its life can be extended. Furthermore, according to the above embodiment, as shown in FIG. 2, the first discharge flow path 20c has a mounting chamber 98 in which the rotation drive motor 40 is mounted. This allows the air flowing out of the first cooling flow path 20b to cool the rotation drive motor 40 located in the mounting chamber 98. In other words, the air used to cool the inner ring 11A of the first rolling bearing 10A can be used to cool the rotation drive motor 40.

[0044] Furthermore, according to the above embodiment, as shown in FIG. 1, the spindle device 1 can cool the outer ring 13A of the first rolling bearing 10A using the first flow path 85 formed in the spindle device main body 3, can cool the rotation drive motor 40 using the second flow path 87, and can cool the outer ring 13B of the second rolling bearing 10B using the third flow path 88.

[0045] B. Other Embodiments: B-1. Alternative embodiment 1: The spindle device 1 of the above embodiment may be used in a vertical machining center.

[0046] B-2. Alternative embodiment 2: In the above embodiment, the first gap GP1 and the second gap GP2 have the same radial dimension in the axial direction, but this is not limited to this. For example, the radial dimension of the pair of first axial gaps GP1b, GP1c of the first gap GP1 may be smaller than the radial dimension of the first flow path forming gap GP1a. This increases the flow path resistance of the pair of first axial gaps GP1b, GP1c, thereby reducing the amount of air leaking from the pair of first axial gaps GP1b, GP1c.

[0047] B-3. ​​Alternative embodiment 3: In the above embodiment, the pair of first axial gaps GP1b, GP1c function as first throttles, so that the flow rate of air flowing from the first front-side passage 22a into the second front-side passage 22b via the first inlet opening 22c is greater than the flow rate of cooling gas leaking from the first front-side passage 22a into the pair of first axial gaps GP1b, GP1c, in the spindle device 1. This relationship holds true at each phase position during the rotational operation of the spindle 10. With this relationship, a larger flow rate of cooling gas is supplied to the first cooling passage 20b, so that the first rolling bearing 10A can be efficiently cooled. Furthermore, the pair of second axial gaps GP2b, GP2c may function as second throttles, so that the flow rate of air flowing from the first rear-side flow passage 122a into the second rear-side flow passage 122b via the second inlet opening 122c is greater than the flow rate of cooling gas leaking from the first rear-side flow passage 122a into the pair of second axial gaps GP2b, GP2c. This relationship holds true at each phase position during the rotational operation of the spindle 10. With this relationship, a greater flow rate of cooling gas is supplied to the second cooling passage 26b, thereby efficiently cooling the second rolling bearing 10B.

[0048] B-4. Alternative embodiment 4: In the above embodiment, the distance between the axis AX and the downstream end 20c6 of the first upstream discharge passage 20c1 in the radial direction of the main shaft 10 may be the same as the distance between the axis AX and the outer circumferential surface of the rotor 41 of the rotation drive motor 40. This allows the cooling gas flowing out from the downstream end 20c6 of the first upstream discharge passage 20c1 to smoothly reach the rotor 41. This allows the rotation drive motor 40 to be efficiently cooled by the cooling gas.

[0049] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features of the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0050] 1...spindle device, 3...spindle device main body, 3a...main body portion, 3b...first cover member, 3c...second cover member, 3fa...inner peripheral surface, 10...spindle, 10A...first rolling bearing, 10B...second rolling bearing, 10C...front cover, 10D, 10E...step portion, 10F...front end portion, 10G...step portion, 10H...spindle inner hole, 10S...spindle cap, 10R...rear end portion, 10T...tool hole, 10fa...outer peripheral surface, 10q...medium diameter portion, 10p...large diameter portion, 11A, 11B...inner ring, 12A, 12B...rolling element, 13A, 13B...outer ring, 14...bearing housing, 14a...housing main body portion, 14b...third cover Bar member, 14c...step portion, 14e...bearing holder, 14fa...inner peripheral surface, 15...movement control mechanism, 16a...bearing holder, 16fa...outer peripheral surface, 17...bearing holder, 18...piston, 18a...cylinder chamber, 19...first coolant passage, 20...first cooling gas passage, 20a...first supply passage, 20a1...first main body passage, 20a2...first spindle passage, 20b...first cooling passage, 20c...first exhaust passage, 20c1...first upstream exhaust passage, 20c2...first downstream exhaust passage, 20c3...first upstream first exhaust passage, 20c4...first upstream second exhaust passage, 20c5...first upstream third exhaust passage, 2 0c6...downstream end, 20d...through hole, 21...downstream end, 22...first radial flow passage, 22a...first front side flow passage, 22b...second front side flow passage, 22c...first inlet opening, 22d...downstream end, 25...groove, 26...second cooling gas flow passage, 26a...second supply flow passage, 26a1...second main body flow passage, 26a2...second main shaft flow passage, 26b...second cooling flow passage, 26c...second exhaust flow passage, 26c1...second upstream exhaust flow passage, 26c2...second downstream exhaust flow passage, 26c3...downstream outlet, 26d...through hole, 28...downstream end, 30...push rod, 30D...large diameter portion, 30F...one end, 30R...other end, 32...collector nut, 34...collar, 35...second air purge passage, 38...third coolant passage, 40...rotary drive motor, 41...rotor, 42...stator, 43...nut, 44...rotary joint, 45...encoder, 45a...magnetic ring, 46...rotary joint, 46b...sensor, 47...fixed joint, 47a...fourth coolant passage, 48...second coolant passage, 49...rotor sleeve, 55...first air purge passage, 81a...tip portion, 81b...tip portion, 83...first port, 84...second port, 85...first passage, 87...second passage, 88...third passage, 90...control device,91...cooling gas supply device, 92...air supply device, 93...hydraulic device, 95...coolant supply device, 96...coolant supply device, 97...circulation pipe, 98...arrangement chamber, 120...air purge flow path, 122...second radial flow path, 122a...first rear side flow path, 122b...second rear side flow path, 122c...second inlet opening, 122d...downstream end, 125...groove, 126...third air purge flow path, 130...coolant flow path, 155...fourth air purge flow path, 156...fifth air purge flow path, 185...opening, AX...axis, GP1...first gap, GP1a...first flow path forming gap, GP1b, GP1c...first axial gap, GP2...second gap, GP2a...second flow path forming gap, GP2b, GP2c...second axial gap, R10A, R10B...area,

Claims

1. A spindle device, a spindle device body; a first rolling bearing lubricated with grease; a spindle rotatably supported by the spindle device main body via the first rolling bearing, the spindle having a front end portion located on a front side and a rear end portion located on a rear side; a rotary drive motor that rotates the main shaft; a spiral first cooling flow passage formed as a groove in the outer peripheral surface of the spindle, the first cooling flow passage being formed in at least a first region in the axial direction of the spindle in which the first rolling bearing is disposed, and being covered by the first rolling bearing in the first region; a first supply flow path that supplies a cooling gas to the first cooling flow path to cool the first rolling bearing, the first supply flow path has a first radial flow path formed across the spindle body and the spindle in the radial direction so as to include a part of a first gap between the spindle body and the spindle in the radial direction, the first radial flow passage is formed on the rear side of the first rolling bearing, the first radial flow passage includes a first front-side flow passage formed in the spindle main body and a second front-side flow passage formed in the spindle, through which the cooling gas from the first front-side flow passage flows, a pair of first axial gaps located on both sides of the first radial flow path in the axial direction among the first gaps function as first throttles that reduce leakage of the cooling gas from the first radial flow path, The spindle device further includes: an arrangement chamber located between an inner peripheral surface of the spindle device body and an outer peripheral surface of the spindle; a first exhaust flow path that exhausts the cooling gas flowing out of the first cooling flow path to the outside, the rotary drive motor is a direct drive motor provided in the placement chamber, The first discharge flow path is a first upstream exhaust flow path formed in the main shaft, which allows the cooling gas flowing out of the first cooling flow path to flow into the arrangement chamber; The placement room; a first downstream-side discharge flow path that discharges the cooling gas in the arrangement chamber to the outside, the first downstream-side discharge flow path being formed in the spindle device main body, a spindle device, wherein a downstream end of the first upstream discharge flow path is located in the axial direction between the rear one of the pair of first axial gaps and the rotation drive motor, and is located rearward of the first radial flow path.

2. The spindle device according to claim 1, a spindle device having a relationship in which, due to its function as the first throttle, the flow rate of the cooling gas flowing from the first front-side flow passage into the second front-side flow passage is greater than the flow rate of the cooling gas leaking from the first front-side flow passage into the pair of first axial gaps.

3. The spindle device according to claim 1, a spindle device, wherein in the radial direction, the distance between the axis of the spindle and the downstream end of the first upstream discharge flow path is the same as the distance between the axis and the outer peripheral surface of a rotor of the direct drive motor.

4. A spindle device, a spindle device body; a first rolling bearing lubricated with grease; a spindle rotatably supported by the spindle device main body via the first rolling bearing, the spindle having a front end portion located on a front side and a rear end portion located on a rear side; a rotary drive motor that rotates the main shaft; a spiral first cooling flow passage formed as a groove in the outer peripheral surface of the spindle, the first cooling flow passage being formed in at least a first region in the axial direction of the spindle in which the first rolling bearing is disposed, and being covered by the first rolling bearing in the first region; a first supply flow path that supplies a cooling gas to the first cooling flow path to cool the first rolling bearing, the first supply flow path has a first radial flow path formed across the spindle body and the spindle in the radial direction so as to include a part of a first gap between the spindle body and the spindle in the radial direction, the first radial flow passage includes a first front-side flow passage formed in the spindle main body and a second front-side flow passage formed in the spindle, through which the cooling gas from the first front-side flow passage flows, a pair of first axial gaps located on both sides of the first radial flow path in the axial direction among the first gaps function as first throttles that reduce leakage of the cooling gas from the first radial flow path, The spindle device further includes: a second rolling bearing located rearward of the first rolling bearing and lubricated with grease; a spiral second cooling flow passage formed as a groove on the outer peripheral surface of the spindle, the second cooling flow passage being formed in at least a second region in the axial direction of the spindle in which the second rolling bearing is disposed, and being covered by the second rolling bearing in the second region; a second supply flow path that supplies the cooling gas to the second cooling flow path to cool the second rolling bearing, the second supply flow path has a second radial flow path formed across the spindle body and the spindle in the radial direction so as to include a part of a second gap between the spindle body and the spindle in the radial direction, the second radial flow passage includes a first rear-side flow passage formed in the spindle main body and a second rear-side flow passage formed in the spindle and through which the cooling gas from the first rear-side flow passage flows, a pair of second axial gaps located on both sides of the second radial flow path in the axial direction among the second gaps function as second throttles that reduce leakage of the cooling gas from the second radial flow path, The spindle device further includes: an encoder for detecting information regarding the rotation of the spindle; a bearing presser positioned rearward of the second rolling bearing and configured to restrict movement of the second rolling bearing in the axial direction; a second exhaust flow path that exhausts the cooling gas flowing out of the second cooling flow path to the outside, the encoder has a ring-shaped member attached to the outer peripheral surface of the bearing holder and interlocking with the rotation of the main shaft, The second discharge flow path is a second upstream exhaust passage connected to the second cooling passage and formed in the main shaft; a second downstream discharge flow path through which the cooling gas flowing out from the second upstream discharge flow path flows, the second downstream discharge flow path being formed in the bearing holder; a downstream outlet of the second downstream discharge flow path is formed on an outer peripheral surface of the bearing holder, the outer peripheral surface being located rearward of the ring-shaped member.

5. The spindle device according to claim 4, a spindle device having a relationship in which, due to its function as the second throttle, the flow rate of the cooling gas flowing from the first rear-side flow passage to the second rear-side flow passage is greater than the flow rate of the cooling gas leaking from the second front-side flow passage to the pair of second axial gaps.

6. The spindle device according to claim 4, The pair of second axial gaps are located between the second rolling bearing and the rotation drive motor in the axial direction.

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