spindle assembly

Abstract

This spindle device comprises: a spindle including a tapered hole positioned on one end and to which a tool is detachably attached, and a spindle cylindrical portion that is positioned on another end side with respect to the tapered hole and that communicates with the tapered hole; a collet chuck that is arranged inside the spindle cylindrical portion and holds the tool; and a draw bar connected to a collet-other-end of the collet chuck to move the collet chuck back and forth along an axial direction of the spindle. The collet chuck comprises a plurality of collet gaps that extend from an annular collet-one-end forming one end to the other end side of the spindle, and form flow paths guiding air to the tapered hole. The spindle cylindrical portion comprises an accommodation space in which the collet-other-end is accommodated in a clamped state. The spindle comprises a plurality of spindle air supply paths for supplying air to the accommodation space in an unclamped state. The spindle device further comprises an annular path that communicates respective upstream sides of the plurality of spindle air supply paths with each other.

Description

[Technical Field]

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

[0002] A spindle of a spindle unit used in a machine tool is provided with a tapered hole for detachably receiving a tool. When the tool is removed, foreign matter such as chips may be trapped on the inner surface of the tapered hole. To address this issue, a technology is known in which air discharge holes are provided on the inner surface of the tapered hole and air is discharged from the air discharge holes to remove foreign matter. However, when air is discharged from the air discharge holes, the air may swirl in the circumferential direction of the tapered hole. The swirling air creates negative pressure near the axis of the tapered hole, which may result in a suction phenomenon in which foreign matter is drawn into the tapered hole. Therefore, the spindle unit of Patent Document 1 is provided with a direct-flow discharge hole that discharges air in a straight line in the axial direction of the tapered hole, in addition to an air discharge hole (swirl-flow discharge hole) provided in the tapered hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-88036 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the spindle device of Patent Document 1, it is necessary to provide a direct flow discharge hole in addition to the swirl flow discharge hole, which may complicate the structure or control. [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 housing; a spindle rotatably supported by the spindle housing, the spindle having a tapered bore located at one end and a tool detachably attached thereto, and a spindle cylinder located at the other end closer to the tapered bore and communicating with the tapered bore; a collet chuck disposed within the spindle cylinder for gripping the tool; and a drawbar connected to the other end of the collet of the collet chuck for moving the collet chuck back and forth along the axial direction of the spindle. The collet chuck has a plurality of claws for gripping the tool, the plurality of claws being arranged circumferentially around the central axis of the spindle, a plurality of collet gaps extending from one end of an annular collet forming one end toward the other end of the spindle and forming a flow path for guiding air to the tapered hole, the plurality of collet gaps being gaps between the respective claws of the plurality of claws, and a collet cam surface, the spindle cylindrical portion having a storage space for storing the other end of the collet in a clamped state, and a partition surface defining the storage space having a cam surface that abuts against the collet cam surface when the collet chuck moves forward. The spindle has a plurality of air supply paths for supplying air to the storage space in an unclamped state. The spindle device further has an annular path connecting the upstream sides of the plurality of spindle air supply paths. According to this aspect, air supplied to the air supply passage temporarily remains in the storage space, passes from the storage space through the gap between the spindle cylindrical portion and the outer periphery of the collet, flows through the collet gap, and is discharged from the tapered hole. Because the air flows through the collet gap and becomes a straight flow, the occurrence of a suction phenomenon near the axis of the tapered hole can be suppressed. Furthermore, according to this aspect, air can be supplied to the storage space from multiple air supply passages, allowing air to be supplied more uniformly to the multiple collet gaps. Furthermore, the spindle device has an annular passage that connects the upstream sides of the multiple spindle air supply passages. The annular passage makes it possible to more uniform the flow rate of air flowing into the multiple spindle air supply passages, thereby making it more uniform the flow rate of air that flows through the storage space and becomes a straight flow after passing through each of the multiple collet gaps.This reduces the likelihood of bias in the flow of air flowing out of each of the multiple collet gaps, making it possible to further suppress the occurrence of the suction phenomenon near the central axis of the tapered hole. (2) In the spindle device of the above aspect, the relative positions of each of the plurality of collet gaps with respect to each of the plurality of air supply paths may be the same. According to this aspect, the paths from the air supply paths to the collet gaps are the same for all of the air supply paths. This makes it less likely that the flow of air ejected from the air supply paths will be uneven, making it easier for the air to flow straight through the tapered hole, and reducing the occurrence of suction. (3) In the spindle device of the above aspect, the number of the plurality of collet gaps may be the same as the number of the plurality of air supply passages, the plurality of collet gaps may be arranged at equal intervals, and the plurality of air supply passages may be arranged at equal intervals. According to this aspect, for all air supply passages, air ejected from the air supply passage is guided to a nearby air gap. This makes it difficult for the air flow to become uneven, and the air flows in a straight line, thereby suppressing the occurrence of suction. (4) In the spindle device of the above aspect, the plurality of air supply passages may extend radially of the spindle, and the phase positions of the plurality of air supply passages may coincide with the phase positions of the plurality of collet gaps. According to this aspect, air ejected from each air supply passage flows smoothly to the nearest collet gap, making the air flow less turbulent. Therefore, the air flows in a straight line, and the occurrence of the suction phenomenon can be suppressed. (5) The spindle unit of the above aspect may further include a biasing member that biases the draw bar in a direction away from the tapered hole along the axial direction, and a cylinder device that presses the draw bar toward the tapered hole in the unclamped state. According to this aspect, the present application can be applied to a spindle unit that includes a biasing member and a cylinder device. (6) The spindle device of the above aspect further includes an inner pipe arranged within the draw bar, the inner pipe having a pipe one end portion forming one end and a pipe other end portion closer to the other end side of the spindle than the pipe one end portion; a pipe air supply passage arranged outside the inner pipe and extending from the pipe one end portion to the pipe other end portion; an other end air flow path arranged close to the pipe other end portion for introducing air into the pipe air supply passage, the other end air flow path distributing air radially inward of the inner pipe; a one end air flow path arranged close to the pipe one end portion for discharging air from the pipe air supply passage, the one end air flow path distributing air radially outward of the inner pipe; a guide sleeve disposed between the spindle and the draw bar, a collet sleeve disposed between the spindle and the draw bar and adjacent to the guide sleeve in the axial direction, a third air supply passage formed by a gap between the guide sleeve and the draw bar and communicating with the one-end air passage, a guide sleeve passage formed at one end of the guide sleeve and extending along the radial direction of the guide sleeve and communicating with the third air supply passage, a collet sleeve passage formed between the spindle and the collet sleeve and having the other end communicating with the guide sleeve passage and the one end communicating with the plurality of spindle air supply passages, and a coolant passage disposed inside the inner piping. According to this aspect, the present application can be applied to a spindle device including an inner piping, a piping air supply passage, a guide sleeve passage, a collet sleeve passage, and a coolant passage. (7) The above-described embodiment may further include an air communication passage formed radially outward of the spindle air supply passage, the air communication passage supplying air from outside to the air supply passage; and a front-side bearing disposed axially near the one end of the spindle and rotatably supporting the spindle, the air communication passage having a one-end-side flow passage located axially closer to the one end than the front-side bearing and formed in the spindle housing and the spindle. According to this embodiment, the air communication passage including the one-end-side flow passage is formed radially outward of the spindle air supply passage, thereby preventing the configuration of the spindle device from becoming more complex than when the air communication passage is formed in the spindle radially inward of the spindle air supply passage, for example, in a shaft hole of the spindle. Furthermore, by forming the one-end-side flow passage in the spindle housing or the spindle, it is not necessary to use an additional member for forming the one-end-side flow passage. (8) In the above aspect, the spindle housing may have a first end face in which a first opening constituting the one-end-side flow passage is formed, the spindle may have a second end face in which a second opening constituting the one-end-side flow passage is formed and which faces the first end face in the axial direction, and the one-end-side flow passage may have an axial flow passage that includes the first opening and the second opening and extends in the axial direction. According to this aspect, a flow passage that spans the spindle housing, which is a non-rotating element, and the spindle, which is a rotating element, can be formed as an axial flow passage. (9) In the above aspect, the spindle housing may include a sleeve that surrounds the spindle in the axial direction, the sleeve having an outer peripheral surface, the first end face, and a third end face protruding from the outer peripheral surface, the spindle housing may further have a fourth end face opposing the third end face in the axial direction, and the spindle device may further include a seal disposed between the third end face and the fourth end face, the seal being compressed in the axial direction in the unclamped state to urge the sleeve toward the second end face. According to this aspect, the first end face and the second end face are in close contact with each other, thereby preventing air from leaking to the outside from the axial flow path. (10) In the above-described embodiment, the spindle may further include a spindle cap that forms the tapered hole, and the spindle housing may further include a front cap that constitutes one end of the spindle housing, and the one-end-side flow passage may be formed in the spindle cap and the front cap. According to this embodiment, the spindle cap and the front cap can be easily assembled to the spindle device, and therefore the one-end-side flow passage can be easily formed in the spindle device. (11) In the above-described embodiment, the spindle may have a cap small diameter portion located radially inward of the spindle housing and a cap large diameter portion located axially closer to the other end than the cap small diameter portion and having an outer diameter larger than that of the cap small diameter portion, and the second end surface may be formed on the cap large diameter portion. According to this embodiment, the second end surface can be easily formed by utilizing the cap large diameter portion of the spindle cap. (12) In the above aspect, the valve may further include a biasing member that biases the draw bar in a direction away from the tapered hole along the axial direction, and a cylinder device that pushes the draw bar toward the tapered hole in the unclamped state, wherein the first end face and the second end face are spaced apart in the clamped state, and the second end face abuts against the first end face in the unclamped state. According to this aspect, the first end face abuts against the second end face in the unclamped state, thereby allowing communication of the axial flow path. (13) In the above aspect, the front cap may further include a presser plate attached to the front cap, the presser plate having the fourth end surface. According to this aspect, the fourth end surface can be formed by the presser plate. (14) In the above aspect, the spindle housing may have a one-end-side housing inner circumferential surface on which an inner circumferential surface opening constituting the one-end-side flow passage is formed, and the spindle may have a one-end-side spindle outer circumferential surface on which an outer circumferential surface opening constituting the one-end-side flow passage is formed, and in the unclamped state, the outer circumferential surface opening is disposed at a position radially opposite the inner circumferential surface opening, and the one-end-side flow passage includes the inner circumferential surface opening and the outer circumferential surface opening, and in the unclamped state, may have a radial flow passage extending in the radial direction. According to this aspect, a flow passage spanning the spindle housing, which is a non-rotating element, and the spindle, which is a rotating element, can be formed as a radial flow passage. 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. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. [Figure 2] Enlarged view of region R2 in Figure 1. [Figure 3] FIG. [Figure 4] An enlarged cross-sectional view of a collet chuck. [Figure 5] A view of the collet chuck viewed along the central axis. [Figure 6] FIG. 11 is a first schematic cross-sectional view of a spindle device according to a second embodiment. [Figure 7] FIG. 10 is a second schematic cross-sectional view of the spindle device according to the second embodiment. [Figure 8] FIG. [Figure 9] FIG. [Figure 10] FIG. [Figure 11] FIG. 10 is a diagram showing the spindle device in an unclamped state. [Figure 12] FIG. 12 is a schematic diagram of a portion of the spindle device shown in FIG. 11 . [Figure 13] FIG. 1 is a diagram for explaining another embodiment of the second embodiment. [Figure 14] FIG. 2 is a diagram for explaining another embodiment of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: FIG. 1 is a schematic diagram showing a longitudinal section of a spindle unit 1 according to a first embodiment. FIG. 2 is an enlarged view of region R2 in FIG. 1. The spindle unit 1 according to this embodiment is a motor-built-in type spindle unit provided in a machine tool such as a machining center. The spindle unit 1 holds a tool for machining a workpiece on its front side. Specifically, the tool is configured by attaching a machining tool to a tool holder. FIG. 1 shows a central axis AX of a spindle 10 of the spindle unit 1. The upper half of the drawing above the central axis AX shows an unclamped state in which the tool holder is released from its grip, while the lower half of the drawing below the central axis AX shows a clamped state in which the tool holder is gripped. This is similarly illustrated in FIG. 4, which will be described later. In addition, with respect to the axial direction along the central axis AX, the side that grips the tool is referred to as the front side, and the side opposite the side that grips the tool is referred to as the rear side. In addition, the upper side of the paper in FIG. 1 corresponds to the vertically upward direction, and the lower side of the paper corresponds to the vertically downward direction.

[0009] Spindle device 1 includes a cylindrical spindle housing 3, spindle 10, front bearing 10A, rear bearing 10B, electric motor 40, draw bar 30, collet chuck 20, disc spring 33 as a biasing member, cylinder device 15, and control device 90. Spindle housing 3 has main elements of spindle device 1 such as spindle 10 and electric motor 40 arranged inside.

[0010] The spindle 10 is rotatably supported by the spindle housing 3 via two bearings, a front bearing 10A and a rear bearing 10B. The spindle 10 has a central axis AX and rotates about the central axis AX when driven by an electric motor 40. The spindle 10 has one end 10F, which is the front end, and another end 10R opposite the one end 10F. The spindle 10 has a tapered bore 10T penetrating in the axial direction, a spindle cylindrical portion 10H, and a spindle cap 10C. The tapered bore 10T is located at one end, i.e., the one end 10F of the spindle 10, and a tool is removably attached to the tapered bore 10T. The spindle cylindrical portion 10H is located closer to the other end than the tapered bore 10T, i.e., closer to the other end 10R of the spindle 10. The spindle cylindrical portion 10H communicates with the tapered bore 10T.

[0011] The front bearing 10A is an angular type rolling bearing located axially forward of the electric motor 40. Two front bearings 10A are located with a gap between them in the axial direction. The front bearing 10A is located between the spindle housing 3 and the spindle 10 in the radial direction of the spindle 10, which is perpendicular to the axial direction. The rear bearing 10B is a roller type rolling bearing located axially rearward of the electric motor 40. The rear bearing 10B is located between the spindle housing 3 and the spindle 10 in the radial direction of the spindle 10.

[0012] Electric motor 40 includes rotor 41 and stator 42. Electric motor 40 is disposed on the outer periphery of spindle 10 within spindle housing 3. Rotor 41 is configured to be rotatable integrally with spindle 10. Control of control device 90 supplies power to stator 42, causing rotor 41 to rotate, which in turn causes spindle 10 to rotate.

[0013] The collet chuck 20 is disposed within the spindle cylindrical portion 10H. The collet chuck 20 moves forward and backward along the axial direction of the spindle 10 in conjunction with the draw bar 30, thereby taking one of two states: a clamped state in which the tool is gripped, and an unclamped state in which the tool is no longer gripped. Specifically, the collet chuck 20 is in the unclamped state when the draw bar 30 is pushed forward by the cylinder device 15 and moves toward the draw bar one end 30F. On the other hand, the collet chuck 20 is in the clamped state when the draw bar 30 is separated from the cylinder device 15 and moves toward the draw bar other end 30R due to the biasing force of the disc spring 33.

[0014] Draw bar 30 is disposed in spindle cylindrical portion 10H. Draw bar 30 is connected to collet chuck 20 and moves collet chuck 20 back and forth along the direction of central axis AX of spindle 10. Draw bar 30 has one draw bar end 30F located on the one end 10F side and another draw bar end 30R located on the other end 10R side. Draw bar 30 can move along the axial direction of spindle 10 by operation of cylinder device 15, which will be described later. Draw bar 30 is connected to spindle 10 so as to move in conjunction with the rotational movement of spindle 10.

[0015] The disc spring 33 is disposed in the spindle cylindrical portion 10H within the spindle 10, between the inner peripheral surface of the spindle 10 and the drawbar 30. The disc spring 33 is disposed in the axial direction of the spindle 10 between a collar 34 disposed on the inner periphery of the spindle 10 and a large-diameter portion 30D formed at the other end 30R of the drawbar 30. Specifically, the disc spring 33 is disposed by being inserted through the outer periphery of the drawbar 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 drawbar 30 on the other end 30R side of the drawbar 30, facing the axial direction. This allows the disc spring 33 to apply a biasing force to the drawbar 30 in a direction away from the tapered bore 10T, i.e., in a direction from the one end 10F side toward the other end 10R side. This biasing force keeps the collet chuck 20 in a clamped state when the cylinder device 15 is not in operation. Note that grease may be applied to the disc spring 33 to reduce frictional force.

[0016] The cylinder device 15 is disposed axially rearward of the draw bar 30. The cylinder device 15 has a piston 18 configured to be movable in the axial direction. The piston 18 faces the other end 30R of the draw bar 30 in the axial direction. When the piston 18 moves forward, the draw bar 30 moves forward by the piston 18 against the biasing force of the disc spring 33. This causes the collet chuck 20 to enter 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 electric motor 40 of the spindle device 1.

[0018] The spindle unit 1 further includes an air supply device 92 and a coolant supply device 95. The operation of the air supply device 92 and the coolant supply device 95 is controlled by the control device 90. The air supply device 92 is, for example, a compressor, and sends pressurized air to a passage provided in the piston 18 of the cylinder device 15. Specifically, the air supply device 92 stops supplying air in the clamped state and supplies air in the unclamped state. In the unclamped state, the air supplied by the air supply device 92 is supplied to the tapered hole 10T, thereby removing chips adhering to the tapered hole 10T. The coolant supply device 95 supplies coolant to a coolant passage 130 extending in the axial direction through an opening 85 on the rear end side of the cylinder device 15. The coolant flows through the coolant passage 130, passes through the draw bar one end 30F, and inside the tool, and is supplied to the machining point, i.e., the cutting edge of the tool.

[0019] As shown in FIG. 1, the drawbar 30 is composed of an outer circumferential drawbar 30A, a push rod 37, and a draw bolt 26. As shown in FIG. 2, an inner pipe 36 is disposed inside the outer circumferential drawbar 30A. Specifically, both ends of the inner pipe 36 protrude in the radially outward direction. The protruding ends of the inner pipe 36 are press-fitted into the inner periphery of the outer circumferential drawbar 30A. A large diameter portion 30D formed on the outer circumferential drawbar 30A near the other end 30R of the drawbar abuts against a disc spring 33. The outer circumferential drawbar 30A is a cylindrical member and has a first rod hole 31H penetrating therethrough in the axial direction. The inner pipe 36 is also a cylindrical member and is disposed within the first rod hole 31H, and has a second rod hole 32H penetrating therethrough in the axial direction. The inner piping 36 has a piping one end portion 36A (FIG. 1) that forms one end, and a piping other end portion 36B that is closer to the other end portion 10R than the piping one end portion 36A. The inner periphery of the push rod 37 is connected to the outer periphery of the outer periphery-side draw bar 30A by threaded engagement. The draw bolt 26 has a generally cylindrical shape. As shown in FIG. 4 (described later), the draw bolt other end portion 28, which is the rear end portion of the draw bolt 26, is connected to the push rod 37 by threaded engagement. As shown in FIG. 4 (described later), the spindle unit 1 further has a guide sleeve 30G and a collet sleeve 30H. The guide sleeve 30G is disposed between the spindle 10 and the draw bar 30. The collet sleeve 30H is disposed between the spindle 10 (more specifically, the spindle body) and the push rod 37. The collet sleeve 30H is disposed adjacent to the guide sleeve 30G in the axial direction. Guide sleeve 30G, collet sleeve 30H, and spindle cap 10C are fitted in this order onto the inner periphery of spindle 10, and spindle cap 10C is fixed to spindle 10 (more specifically, to the spindle body) with bolts. Guide sleeve 30G and collet sleeve 30H are axially sandwiched between step portion 10D of spindle 10 and spindle cap 10C, and are fixed to spindle 10 (more specifically, to the spindle body). Spindle cap 10C, guide sleeve 30G, and collet sleeve 30H rotate together with the spindle body and constitute spindle 10.

[0020] Next, the configuration related to the various flow paths of the spindle unit 1 will be described with reference to Figures 1 and 2. The criteria for "upstream" and "downstream" for the various flow paths are based on the flow direction of the fluid supplied from the air supply device 92 and the coolant supply device 95. The spindle unit 1 is equipped with a coolant flow path 130 (Figures 1 and 2) that supplies coolant to a machining point to be machined by a tool gripped by the collet chuck 20, and an air supply path 120 (Figures 1 and 2) that supplies air to be blown into the tapered hole 10T to the tapered hole 10T.

[0021] The coolant passage 130 includes a first coolant passage 19 (FIG. 1) formed in the cylinder device 15, a fourth coolant passage 47a (FIG. 1) formed in the fixed joint 47, a second coolant passage 48 (FIG. 2) formed in the rotary joint 46, a third coolant passage 38 (FIGS. 1 and 2) formed in the inner pipe 36, a fifth coolant passage 49, and a sixth coolant passage 50. As shown in FIG. 2, the third coolant passage 38 as a coolant passage is disposed inside the inner pipe 36 and is formed by the second rod hole 32H of the inner pipe 36. As shown in FIG. 1, the fifth coolant passage 49 is disposed inside the push rod 37. The sixth coolant passage 50 is disposed inside the cylindrical spool 25 (FIG. 4) disposed inside the draw bolt 26. The 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, the third coolant passage 38, the fifth coolant passage 49, and the sixth coolant passage 50 in this order, passing through the tool and being supplied to the machining point, which is the cutting edge of the tool, located on the one end 10F side. In this manner, 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.

[0022] Air supply passage 120 includes an upstream air supply passage 55 (FIGS. 1 and 2) formed in a non-rotating element of spindle unit 1, and a downstream air supply passage 56 (FIG. 1) located downstream of upstream air supply passage 55 and formed in a rotating element of spindle unit 1. Upstream air supply passage 55 is formed in piston 18, which is a non-rotating element. Upstream air supply passage 55 is also referred to as first air supply passage 55. Downstream air supply passage 56 includes second air supply passage 35 (FIGS. 1 and 2) formed in draw bar 30 and between draw bar 30 and inner piping 36, third air supply passage 125 (FIG. 1) formed by the gap between spindle 10 and draw bar 30, sixth air supply passage 126 (FIG. 1) as a guide sleeve passage, fourth air supply passage 155 (FIG. 1) as a collet sleeve passage formed in spindle 10, and spindle air supply passage 156 (FIG. 1).

[0023] As shown in FIG. 2, the downstream end of the first air supply passage 55 is an opening formed in the piston 18 at a position facing the draw bar 30 in the axial direction. When the end faces of the piston 18 and the draw bar 30 abut against each other in the unclamped state, the first air supply passage 55 of the piston 18 is connected to the second air supply passage 35 of the draw bar 30. The second air supply passage 35 has an upstream flow passage 35A formed in the outer peripheral draw bar 30A, an other-end air flow passage 35C, a downstream flow passage 35B, and an one-end air flow passage 35D (FIG. 1). The downstream flow passage 35B, which serves as a piping air supply passage, is formed by a gap between the inner peripheral surface of the outer peripheral draw bar 30A and the outer peripheral surface of the inner piping 36. The downstream flow passage 35B is disposed outside the inner piping 36 and extends from one piping end 36A to the other piping end 36B. The downstream flow passage 35B communicates with a plurality of spindle air supply passages 156, which will be described later. The other-end air flow path 35C is located between the upstream-side flow path 35A and the downstream-side flow path 35B. The other-end air flow path 35C is located close to the other end 36B of the pipe. The other-end air flow path 35C extends in the radial direction of the inner pipe 36. Air flows through the other-end air flow path 35C radially inward of the inner pipe 36 and flows into the downstream-side flow path 35B. The one-end air flow path 35D (FIG. 1) is located between the downstream-side flow path 35B and the third air supply path 125. The one-end air flow path 35D is located close to the one end 36A of the pipe. The one-end air flow path 35D extends in the radial direction of the push rod 37 and the outer periphery-side draw bar 30A. Air flows through the one-end air flow path 35D radially outward of the push rod 37 and the outer periphery-side draw bar 30A and flows out into the third air supply path 125.

[0024] As shown in FIG. 1, the third air supply passage 125 is formed by a gap between the guide sleeve 30G and the push rod 37. The third air supply passage 125 is in communication with the second air supply passage 35. As shown in FIG. 4, which will be described later, the guide sleeve 30G has a large-diameter portion 30I protruding radially outward from one end. The large-diameter portion 30I abuts against a stepped portion 10D of the main shaft 10. A fourth air supply passage 155 is formed between the inner periphery of the main shaft 10 and the outer periphery of the large-diameter portion 30I. The sixth air supply passage 126 is formed on the stepped portion 10D side of the main shaft 10 of the large-diameter portion 30I. The sixth air supply passage 126 is formed on the stepped portion 10D side of the large-diameter portion 30I of the guide sleeve 30G and extends radially of the large-diameter portion 30I. The sixth air supply passage 126 connects the third air supply passage 125 and the fourth air supply passage 155. The fourth air supply passage 155 is an annular flow path (annular passage) around the central axis AX, formed between the inner periphery of the spindle 10 and the outer periphery of the collet sleeve 30H. The upstream end of the fourth air supply passage 155, i.e., the other end, is connected to the third air supply passage 125 via the sixth air supply passage 126, and the downstream end of the fourth air supply passage 155, i.e., one end, is connected to the upstream end of the spindle air supply passage 156. More specifically, a plurality of spindle air supply passages 156 are provided, and the fourth air supply passage 155, which is an annular passage, connects the upstream ends of the plurality of spindle air supply passages 156 to each other. The downstream end of the spindle air supply passage 156 opens into the spindle cylindrical portion 10H, as will be described in detail later.

[0025] FIG. 3 is a perspective view of the collet chuck 20 and the draw bolt 26. FIG. 4 is an enlarged cross-sectional view of the collet chuck 20 and the draw bolt 26 in the unclamped state. In FIG. 4, the air flow is indicated by arrows. FIG. 5 is a view of the collet chuck 20 in the unclamped state as viewed from the front along the central axis AX. In FIG. 5, the inner periphery of the spindle 10 and the outer periphery of the collet sleeve 30H along line IV-IV in FIG. 4 are indicated by dashed lines. The front and rear directions in FIGS. 3 to 5 are the same as those in FIG. 1. As shown in FIG. 3, the collet chuck 20 has an annular collet one end 20a forming one end, multiple collet gaps 20b, and a collet other end 20c forming the other end. As shown in FIG. 4, the collet one end 20a is positioned closer to the tapered hole 10T than the collet other end 20c. 3, the plurality of collet gaps 20b extend from one collet end 20a to the other end 10R (FIG. 1) which is the other end side of the spindle 10. The plurality of collet gaps 20b form a flow path that guides air to the tapered hole 10T.

[0026] As shown in Fig. 3, the collet chuck 20 has collet jaws 21 as a plurality of jaw portions. In this embodiment, the collet chuck 20 has six collet jaws 21. The plurality of collet jaws 21 are attached to the outer peripheral surface of a draw bolt one end 27, which is the front end of the draw bolt 26, so as to surround the entire circumference of the draw bolt one end 27 (Fig. 4). A spool 25 is disposed inside the draw bolt 26. The spool 25 is slidably inserted into the draw bolt 26.

[0027] As shown in FIG. 3, the collet jaws 21 have a shape roughly obtained by dividing a cylinder into six sections along the central axis of the cylinder. The collet jaws 21 have a shape extending along the central axis AX of the collet chuck 20. The collet jaws 21 have a collet base 22, a collet cylindrical section 23, a collet tip section 24, a jaw inclined surface 21a (FIG. 4), a first jaw cam surface 21b serving as a collet cam surface, a collet recess 21c, and a second jaw cam surface 21d. The collet base 22 is the rear end of the collet jaws 21. The collet tip section 24 is the front end. The collet cylindrical section 23 is located between the collet base 22 and the collet tip section 24. The thickness of the collet base 22 is thicker than the thickness of the collet cylindrical section 23. The inner peripheral surface of the collet base 22 protrudes inward from the inner peripheral surface of the collet cylindrical section 23. On the inner peripheral surface of collet claw 21, claw inclined surface 21a is provided at the boundary between collet base portion 22 and collet cylindrical portion 23. The outer peripheral surface of collet base portion 22 protrudes outward beyond the outer peripheral surface of collet cylindrical portion 23. On the outer peripheral surface of collet claw 21, a first claw cam surface 21b is provided at the boundary between collet base portion 22 and collet cylindrical portion 23. Claw inclined surface 21a and first claw cam surface 21b are surfaces that are inclined with respect to central axis AX. The tip of the outer peripheral surface of collet tip portion 24 protrudes toward main shaft 10 relative to the outer peripheral surface of collet cylindrical portion 23. A second claw cam surface 21d is provided on the outer peripheral surface of collet tip portion 24. Second claw cam surface 21d is part of the surface connecting the protruding tip of collet tip portion 24 and collet cylindrical portion 23. Second claw cam surface 21d is inclined with respect to central axis AX. An inner peripheral convex portion 24b is formed on the inner peripheral surface of collet tip portion 24, protruding toward center axis AX relative to the inner peripheral surface of collet cylindrical portion 23. Inner peripheral convex portion 24b engages with a pull stud of a tool (not shown).

[0028] Collet recess 21c is formed on the outer peripheral surface of collet base 22, recessed inward. Coil spring 71 is wound around each collet recess 21c, pressing collet claws 21 against draw bolt 26. Collet claws 21 are fixed at intervals in the circumferential direction. Key structures (not shown) that fit into the collet claws 21 and the draw bolt 26 are formed. This prevents the collet claws 21 from rotating relative to one end 27 of the draw bolt. The gap between two adjacent collet claws 21 is collet gap 20b.

[0029] As shown in FIG. 4, the draw bolt 26 has a bolt slope 26a formed in a position facing the claw slope 21a. The collet sleeve 30H has a spindle cam surface 10M formed as a cam surface facing the first claw cam surface 21b in the clamped state. The bolt slope 26a and the claw slope 21a come into contact with each other. This allows the inner peripheral convex portion 24b of the collet claw 21 to hold the pull stud of a tool (not shown). When the draw bar 30 moves forward, the first claw cam surface 21b comes into contact with the spindle cam surface 10M. The collet claw 21 then transitions from the clamped state to the unclamped state. This causes the inner peripheral convex portion 24b of the collet claw 21 to open radially outward relative to the pull stud of the tool (not shown). The collet sleeve 30H has a spindle convex portion 10P formed in a position facing the second claw cam surface 21d. Spindle protrusion 10P is a portion of spindle cylindrical portion 10H that protrudes radially inward from the end adjacent to tapered hole 10T. When drawbar 30 moves backward, second pawl cam surface 21d comes into contact with spindle protrusion 10P. Collet pawl 21 then transitions from its unclamped state to its clamped state.

[0030] As shown in Figures 1 and 4, storage space 10N of spindle 10 is a space in which collet base 22 is stored in the clamped state. As shown in Figure 4, spindle cam surface 10M is a partition surface that defines storage space 10N. Fourth air supply passage 155 extends along the direction of central axis AX. Spindle air supply passage 156 extends along the radial direction of spindle 10. The downstream end of spindle air supply passage 156 opens into storage space 10N.

[0031] As shown in FIG. 5 , a plurality of spindle air supply passages 156 are provided at intervals in the circumferential direction of the spindle 10. The spindle air supply passages 156 are provided corresponding to the collet gaps 20b. In this embodiment, the number of spindle air supply passages 156 is six, the same as the number of collet gaps 20b. The internal space of the spool 25 is a sixth coolant flow passage 50 through which coolant flows. The plurality of collet gaps 20b are arranged at equal intervals in the circumferential direction. The plurality of spindle air supply passages 156 are arranged at equal intervals in the circumferential direction. That is, the relative positions of each of the six collet gaps 20b with respect to one spindle air supply passage 156 are the same for all spindle air supply passages 156. Furthermore, the phase positions of the plurality of air supply passages 120 and the plurality of collet gaps 20b coincide with each other. Here, the phase positions refer to positions in the circumferential direction of the spindle 10.

[0032] When a tool is attached, the tool is inserted into the internal space of the collet chuck 20 and the draw bar 30 moves rearward. In conjunction with this, the collet chuck 20 moves rearward and deforms to tighten the pull stud of the tool, gripping the tool. On the other hand, when the tool is removed for tool replacement, the draw bar 30 moves forward. In conjunction with this, the collet chuck 20 moves forward and deforms so that the inner peripheral surface of the collet chuck 20 moves away from the pull stud of the tool. The tool is pulled forward and a new tool is inserted.

[0033] When a tool is removed for tool replacement, air is ejected toward the tapered bore 10T, preventing chips generated during machining from adhering to the tapered bore 10T. If the ejected air swirls around the tapered bore 10T, negative pressure may be created near the axis of the tapered bore 10T, resulting in a suction phenomenon in which chips are drawn into the tapered bore. If a suction phenomenon occurs, the drawn-in chips may adhere to the tapered bore 10T, potentially reducing tool installation accuracy. To address this issue, the inventors devised a method for directing air flow in a straight line along the central axis AX. This suppresses air swirl and prevents the suction phenomenon, thereby improving the cleanliness of the tapered bore 10T and improving tool installation accuracy. Specifically, in this embodiment, the spindle air supply passage 156 opens to the storage space 10N. As a result, the air ejected from spindle air supply passage 156 temporarily remains in storage space 10N and flows from storage space 10N toward tapered hole 10T. This reduces the bias of the flow compared to a structure in which the air flows directly into tapered hole 10T without passing through storage space 10N, making it possible to make the flow straight. Furthermore, in this embodiment, the air flows through collet gap 20b extending from storage space 10N in the axial direction and is supplied to tapered hole 10T. Because the air flows along collet gap 20b, the air flowing out into tapered hole 10T can be made to flow straight.

[0034] In this embodiment, a plurality of spindle air supply passages 156 are provided. This makes it possible to prevent uneven distribution of air supplied to storage space 10N, thereby enabling more uniform supply of air to the plurality of collet gaps 20b. In this embodiment, the relative positions of the plurality of collet gaps 20b with respect to one spindle air supply passage 156 are the same for all spindle air supply passages 156. Furthermore, the number of the plurality of collet gaps 20b is the same as the number of the plurality of spindle air supply passages 156. The plurality of collet gaps 20b are arranged at equal intervals. Furthermore, the plurality of spindle air supply passages 156 are arranged at equal intervals. The phase positions of the plurality of spindle air supply passages 156 and the phase positions of the plurality of collet gaps 20b match. As a result, air ejected from each spindle air supply passage 156 passes through storage space 10N and flows smoothly to the nearest collet gap 20b, reducing uneven air flow and reducing turbulence in the straight air flow.

[0035] According to the first embodiment described above, the collet chuck 20 has multiple collet gaps 20b extending from the collet one end 20a toward the other end 10R of the spindle 10. The spindle cylindrical portion 10H has multiple air supply paths 120 for supplying air to the storage space 10N in the unclamped state. As a result, air supplied to the spindle air supply path 156 temporarily remains in the storage space 10N, flows from the storage space 10N through the collet gaps 20b, and is discharged from the tapered bore 10T. Because the air passes through the collet gaps 20b and becomes a straight flow, the occurrence of a suction phenomenon near the central axis AX of the tapered bore 10T can be suppressed. The spindle unit 1 also has a fourth air supply path 155 as a circular path connecting the upstream sides of the multiple spindle air supply paths 156. The fourth air supply passage 155 makes the flow rate of air flowing into the multiple spindle air supply passages 156 more uniform, thereby making the flow rate of air that flows through the storage space 10N and passes through each of the multiple collet gaps 20b to become a straight flow more uniform. This makes it less likely that the flow of air flowing out of each of the multiple collet gaps 20b will be uneven, further reducing the occurrence of the suction phenomenon near the central axis AX of the tapered bore 10T. Furthermore, the partition surface that defines the storage space 10N has the spindle cam surface 10M, so air can be supplied to the storage space 10N that has the spindle cam surface 10M. Furthermore, the multiple collet gaps 20b are gaps between each of the multiple collet jaws 21. This allows air to flow through the gaps between the collet jaws 21.

[0036] The relative position of each of the plurality of collet gaps 20b with respect to each of the plurality of spindle air supply passages 156 is the same for each of the plurality of spindle air supply passages 156. As a result, the path from the spindle air supply passage 156 to the collet gap 20b is the same for all of the spindle air supply passages 156. As a result, the flow of air ejected from the spindle air supply passage 156 is less likely to be uneven, and the air is more likely to flow straight through the tapered hole 10T, making it possible to further suppress the occurrence of the suction phenomenon.

[0037] The number of the plurality of collet gaps 20b is the same as the number of the plurality of spindle air supply paths 156. The plurality of collet gaps 20b are arranged at equal intervals. The plurality of spindle air supply paths 156 are arranged at equal intervals. As a result, for all spindle air supply paths 156, air ejected from the spindle air supply paths 156 is guided to the nearest collet gap 20b. This makes it difficult for the air flow to become uneven, and the air flows in a straight line, thereby suppressing the occurrence of the suction phenomenon. Furthermore, the phase positions of the plurality of spindle air supply paths 156 and the phase positions of the plurality of collet gaps 20b match. As a result, air ejected from each spindle air supply path 156 flows smoothly to the nearest collet gap 20b, making it difficult for the air flow to become turbulent. This makes it possible for the air to flow in a straight line, thereby suppressing the occurrence of the suction phenomenon.

[0038] The spindle unit 1 includes a disc spring 33 that biases the draw bar 30, and a cylinder device 15 that presses the disc spring 33. As a result, the present application can be applied to a spindle unit 1 that includes the disc spring 33 and the cylinder device 15. The spindle unit 1 also includes an inner piping 36, a downstream flow path 35B that is arranged outside the inner piping 36, a third coolant flow path 38 that is arranged inside the inner piping 36, a sixth air supply path 126, and a fourth air supply path 155. As a result, the present application can be applied to a spindle unit 1 that includes the inner piping 36, the downstream flow path 35B, the sixth air supply path 126, the fourth air supply path 155, and the third coolant flow path 38.

[0039] B. Alternatives to the First Embodiment: (B1) In the first embodiment described above, the phase positions of the multiple air supply passages 120 and the phase positions of the multiple collet gaps 20b match. Alternatively, the phase positions of the multiple spindle air supply passages 156 and the phase positions of the multiple collet gaps 20b may not match. Even if the phase positions of the multiple spindle air supply passages 156 and the phase positions of the multiple collet gaps 20b are misaligned, the air ejected from the multiple spindle air supply passages 156 each flows into the nearest collet gap 20b via the same path, making it less likely that the air flow will be uneven. This allows the air to flow in a straight line, reducing the occurrence of the suction phenomenon.

[0040] (B2) In the first embodiment described above, the number of collet gaps 20b is the same as the number of spindle air supply passages 156. The collet gaps 20b are arranged at equal intervals. The spindle air supply passages 156 are arranged at equal intervals. Alternatively, for example, a configuration may be used in which the number of collet gaps 20b is greater than the number of spindle air supply passages 156. In this configuration, it is preferable that the relative positions of the collet gaps 20b with respect to the spindle air supply passages 156 are the same for all spindle air supply passages 156. This makes it less likely that unevenness will occur in the air flow.

[0041] (B3) In the first embodiment, multiple spindle air supply passages 156 were provided, but only one may be provided. Even in this case, the air supplied from spindle air supply passage 156 to storage space 10N is circulated in the circumferential direction by storage space 10N, and is thereby supplied to multiple collet gaps 20b.

[0042] C. Second embodiment: FIG. 6 is a first schematic diagram showing a cross-section of the spindle device 11 of the second embodiment. FIG. 7 is a second schematic diagram showing a cross-section of the spindle device 11 of the second embodiment. FIG. 6 is a diagram showing the clamped state, and FIG. 7 is a diagram showing the unclamped state. The main difference between the spindle device 11 and the spindle device 1 of the first embodiment is that the air supply passage 320 is formed radially outward from the shaft hole 10J of the spindle 10. The air supply passage 320 includes an upstream air supply passage 355 ( FIG. 6 ) formed in a non-rotating element of the spindle device 11, and a downstream air supply passage 356 ( FIG. 6 ) located downstream of the upstream air supply passage 355 and formed in a rotating element of the spindle device 11. Details of the upstream air supply passage 355 and the downstream air supply passage 356 will be described later. In the spindle device 11, components similar to those in the first embodiment are designated by the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0043] The spindle device 11 includes a cylindrical spindle housing 3, a spindle 10, a front bearing 10A, a rear bearing 10B, an electric motor 40, a draw bar 230, a collet chuck 20, a disc spring 33 as a biasing member, a cylinder device 15, and a control device 90.

[0044] The main elements of the spindle device 1, such as the spindle 10 and the electric motor 40, are arranged inside the spindle housing 3. The spindle housing 3 has a housing main body 17 that accommodates the electric motor 40, a bearing housing 12 fixed to the other end of the housing main body 17, and a cylindrical front cap 14 that constitutes one housing end, which is the front end (one end) of the spindle housing 3. The front cap 14 is fixed to the housing main body 17 by bolts together with a first front outer ring holder 61, which will be described later.

[0045] The spindle 10 has an axially extending shaft hole 10J that includes a tapered bore 10T and a spindle cylinder portion 10H as elements. The front bearing 10A and the rear bearing 10B rotatably support the spindle 10 relative to the spindle housing 3. The collet chuck 20 is disposed within the spindle cylinder portion 10H and is configured to be able to grip a tool. In this embodiment, the front bearing 10A and the rear bearing 10B are angular rolling bearings. The front bearing 10A is located forward of the electric motor 40 and is located near one end 10F in the axial direction. The rear bearing 10B is located rearward of the electric motor 40 and is located near the other end 10R in the axial direction.

[0046] The draw bar 230 is connected to the other end of the collet of the collet chuck 20 and moves the collet chuck 20 back and forth along the axial direction. Unlike the first embodiment, the draw bar 230 differs from the draw bar 30 in that it does not have separate inner and outer piping but a single piping. The draw bar 230 has a rod hole 382H penetrating it in the axial direction. The rod hole 382H communicates with the fourth coolant passage 47a of the fixed joint 47. The rod hole 382H forms a rod coolant passage 338 through which coolant supplied from the fourth coolant passage 47a flows. The coolant flowing through the rod coolant passage 338 passes through the tool and is supplied to the machining point, i.e., the cutting edge of the tool, located at the one end 10F. Similar to the first embodiment, the draw bar 230 has a draw bolt at one end and a cylindrical spool disposed inside the draw bolt. The interior of this cylindrical spool defines the downstream side of the rod coolant passage 338 .

[0047] Although the illustration of the collet chuck 20 in the second embodiment is simplified, it has the same configuration as the collet chuck 20 in the first embodiment (FIG. 3). Also, as in the first embodiment, the spindle cylindrical portion 10H has a storage space 10N in which the other end 20c of the collet (FIG. 3) is stored in the clamped state. Also, as in the first embodiment, the partition surface that defines the storage space 10N has a spindle cam surface 10M (FIG. 8) that abuts against the first jaw cam surface 21b (FIG. 8) serving as a collet cam surface when the collet chuck 20 moves forward.

[0048] The spindle device 11 further has a front member 234 and a rear member 235 arranged on the outer periphery of a push rod 337 of the draw bar 230. The front member 234 and the rear member 235 are each cylindrical. The front member 234 and the rear member 235 are arranged with a gap between them in the axial direction. A disc spring 33 is arranged in a compressed state between the front member 234 and the rear member 235. The front end of the disc spring 33 abuts against the front member 234, and the rear end of the disc spring 33 abuts against the rear member 235. The rear member 235 is fixed to the outer periphery of the push rod 337. As a result, the rear member 235 moves in conjunction with the push rod 337. The front member 234 is arranged in a shaft hole 10J of the spindle 10. The rear member 235 is pushed forward by the piston 18 of the cylinder device 15 as the piston 18 moves forward. As a result, the push rod 337 moves forward in conjunction with the rear member 235, and the collet chuck 20 also moves forward. As shown in FIG. 7, when the collet chuck 20 moves forward, the collet claws 21 open within the axial hole 10J, and the spindle unit 11 enters an unclamped state. The piston 18 moves forward and backward by supplying hydraulic oil to and discharging hydraulic oil from the cylinder chamber using a hydraulic device 93 provided in the spindle unit 11. The hydraulic device 93 is also provided in the spindle unit 1 of the first embodiment, but is not shown in the first embodiment.

[0049] Fig. 8 is a diagram showing a front portion of the spindle device 11. Fig. 9 is a schematic diagram showing a part of the spindle device 11. Fig. 10 is a diagram showing a rear portion of the spindle device 11. Figs. 8 and 9 are diagrams showing the spindle device 11 in a clamped state. The configuration of the spindle device 11 will be further described with reference to Figs. 8 to 10.

[0050] As shown in FIG. 8 , the spindle device 11 further includes a first front outer race retainer 61, a second front outer race retainer 62, and a front inner race retainer 64. The first front outer race retainer 61 and the second front outer race retainer 62 clamp the outer race of the front bearing 10A in the axial direction, thereby restricting axial movement of the outer race of the front bearing 10A. The second front outer race retainer 62 is disposed on the inner circumferential surface of the housing main body 17. The first front outer race retainer 61 is clamped between the housing main body 17 and the front cap 14, thereby fixing its position. The front inner race retainer 64 and a stepped surface 142 formed on the outer circumferential surface of the spindle main body 10E of the spindle 10 clamp the inner race of the front bearing 10A, thereby restricting axial movement of the inner race of the front bearing 10A. The front inner ring holder 64 is sandwiched between the spindle body 10E and the spindle cap 10C that constitutes the spindle 10.

[0051] The spindle unit 11 further includes a sleeve 69, a retaining plate 16, and a seal 79. The sleeve 69 is cylindrical and positioned radially between the front cap 14 and the spindle cap 10C. The sleeve 69 surrounds the spindle cap 10C, with its axial center at the center. The sleeve 69 is axially movably disposed on the inner peripheral surface of the front cap 14. As shown in FIG. 9 , a protrusion 69b is formed on the outer periphery of the sleeve 69, protruding radially outward from an outer peripheral surface 69fa. The protrusion 69b is formed circumferentially on the outer peripheral surface 69fa of the sleeve 69. The rear end surface of the protrusion 69b abuts against a step portion of the front cap 14. A third end surface 69e, which is the front end surface of the protrusion 69b, abuts against the seal 79, which will be described later. The third end surface 69e is also a component of the protrusion 69b and therefore protrudes radially outward from the outer peripheral surface 69fa. The retaining plate 16 is disk-shaped and attached to the front cap 14 with bolts. A fourth end face 14e, which is the rear end face of the retaining plate 16, abuts against the sealant 79. The third end face 69e and the fourth end face 14e face each other in the axial direction and sandwich the sealant 79. The sealant 79 is positioned so as to fit into the recess 14b defined by the front cap 14 and the retaining plate 16. The sleeve 69 further has a first end face 69fb, which is the end face on the other (rear) end side in the axial direction. The sleeve 69 is pressed toward the front cap 14 by the retaining plate 16 and the sealant 79, but rotates slightly around the central axis AX due to frictional force as the spindle 10 rotates. The sleeve 69 can also be considered a component of the spindle housing 3.

[0052] 9, the seal 79 is an annular elastic member arranged to surround the outer peripheral surface 69fa of the sleeve 69. For example, synthetic rubber is used as the seal 79. The seal 79 is arranged between the third end face 69e and the fourth end face 14e in an axially compressed state. The seal 79 prevents air flowing through the air supply path 320 from leaking to the outside.

[0053] The spindle cap 10C forming the tapered hole 10T (FIG. 8) has a cap small diameter portion 10Cb located radially inside the spindle housing 3 and a cap large diameter portion 10Ca having an outer diameter larger than that of the cap small diameter portion 10Cb. 10Cb The cap large diameter portion 10Ca is located closer to the other end (rearward) than the second smallest inner circumference of the first front outer ring retainer 61 and the inner circumference of the sleeve 69. The cap large diameter portion 10Ca has a second end face 10fb that faces the first end face 69fb of the sleeve 69 in the axial direction. In the clamped state, the first end face 69fb and the second end face 10fb are spaced apart in the axial direction.

[0054] As shown in FIG. 10 , the spindle unit 11 further includes a first rear outer ring holder 67, a second rear outer ring holder 68, a rear inner ring holder 66, a closing plate 65, and a preload spring 148. The closing plate 65 is disk-shaped and fixed to the inner circumferential surface of the bearing housing 12. The bearing housing 12 is fixed to the other end of the housing main body 17. The bearing housing 12 is a component of the spindle housing 3. The first rear outer ring holder 67 and the second rear outer ring holder 68 are fixed to each other with bolts 82. The first rear outer ring holder 67 and the second rear outer ring holder 68 restrict axial movement of the outer ring of the rear bearing 10B. The rear inner ring holder 66 is fastened to the spindle main body 10E with bolts 146. Rear inner ring holder 66 and the stepped surface 144 formed on the outer peripheral surface of the spindle body 10E sandwich the inner ring of the rear side bearing 10B, Rear bearing 10BThe preload spring 148 applies a preload to the rear bearing 10B and the front bearing 10A. A plurality of preload springs 148 are arranged at regular intervals in the circumferential direction centered on the axial direction. One end of the preload spring 148 abuts against the closure plate 65, and the other end of the preload spring 148 abuts against the second rear outer ring retainer 68. As a result, the second rear outer ring retainer 68 receives a rearward external force F from the preload spring 148, and in the clamped state, it is displaced rearward by a value VL compared to the unclamped state. In addition, the first rear outer ring retainer 67, which is integrated with the second rear outer ring retainer 68 by the bolt 82, is also displaced rearward by a value VL, thereby pressing the outer ring of the rear bearing 10B rearward. As a result, a preload is applied to the rear bearing 10B and the front bearing 10A. In this embodiment, the value VL is 0.2 mm. When the state of the spindle device 11 transitions from the clamped state to the unclamped state, the rear member 235 and the draw bar 230 are pushed forward by the piston 18. In this case, the spindle 10 receives a thrust force toward the front side of the piston 18 against the pressing force of the disc spring 33, and is thereby displaced slightly forward. In this embodiment, the spindle 10 is displaced 0.2 mm further forward in the unclamped state than in the clamped state.

[0055] Next, the air supply passage 320 will be described in detail with reference to FIGS. 11 and 12 in addition to FIGS. 7 to 10. FIG. 11 is a diagram illustrating the spindle unit 11 in an unclamped state. FIG. 12 is a schematic diagram of a portion of the spindle unit 11 shown in FIG. 11. With respect to the air supply passage 320, the upstream side and downstream side are defined based on the air flow direction. As shown in FIG. 7, an upstream end 331 of the air supply passage 320 is formed at the rear end of the spindle housing 3 (more specifically, the housing main body 17). The air supply device 92 communicates with the upstream end 331 via a circulation pipe. When the spindle unit 11 is in an unclamped state, the air supply device 92 sends pressurized air into the air supply passage 320 via the upstream end 331.

[0056] The air supply passage 320 includes, in order from upstream to downstream, an air communication passage 321 (FIGS. 7, 8, and 10) including an upstream end portion 331, an annular passage 30Ha (FIGS. 8 and 11), and a spindle air supply passage 327 (FIG. 8) connected to the downstream end portion of the air communication passage 321 via the annular passage 30Ha. As shown in FIG. 8, the downstream end of the spindle air supply passage 327 opens into the storage space 10N. Air that flows from the spindle air supply passage 327 into the storage space 10N temporarily remains in the storage space 10N and then flows from the storage space 10N through the collet gaps 20b toward the tapered hole 10T. In this embodiment, the number of spindle air supply passages 327 is six, the same as in the first embodiment. The air supplied from the spindle air supply passage 327 to the storage space 10N flows through the storage space 10N formed in the circumferential direction and then flows into the six collet gaps 20b (FIG. 3).

[0057] As shown in FIG. 7, the air communication passage 321 is formed radially outward of the spindle air supply passage 327. As shown in FIGS. 8 and 9, the air communication passage 321 has, in order from upstream to downstream, an upstream communication passage 321A formed in the non-rotating element and a downstream communication passage 321C formed in the rotating element. As such, the upstream communication passage 321A is a passage formed in the non-rotating element of the spindle unit 11, and the downstream communication passage 321C is a passage formed in the rotating element of the spindle unit 11. In this embodiment, the upstream communication passage 321A is formed in the housing main body 17, the first front outer ring retainer 61, and the front cap 14, which are non-rotating elements. The upstream communication passage 321A allows air that has flowed in from the upstream end 331 (FIG. 10) to flow to the inside of the front cap 14, which is located forward of the front bearing 10A. The downstream-side communication passage 321C is formed in the rotating elements of the sleeve 69, spindle cap 10C, front inner race retainer 64, and spindle body 10E. Of the upstream-side communication passage 321A and the downstream-side communication passage 321C, the passage located axially closer to one end 10F than the front bearing 10A is the one called the one-end-side passage 321B. In this embodiment, the one-end-side passage 321B is formed in the first front outer race retainer 61, the front cap 14 which is part of the spindle housing 3, the sleeve 69, the spindle cap 10C which is part of the spindle 10, and the front inner race retainer 64. In other words, the one-end-side passage 321B is formed in the downstream portion of the upstream-side communication passage 321A and the upstream portion of the downstream-side communication passage 321C.

[0058] As shown in Fig. 8, the air supply passage 320 is a flow path that branches into two from a connecting passage 69a (Figs. 8 and 9), which is an annular groove formed in the outer peripheral surface of the sleeve 69, to an annular passage 30Ha, which will be described later. These two branched flow paths are formed at positions that face each other in the radial direction. Note that the number of branched flow paths in the air supply passage 320 from the connecting passage 69a (Figs. 8 and 9) to an annular passage 30Ha, which will be described later, is not limited to two as described above, and may be, for example, three.

[0059] The front cap 14 is formed with, in order from the upstream side to the downstream side, an axial flow passage 14a shown in FIG. 8 and a radial flow passage 14c shown in FIG. 9 connected to the axial flow passage 14a. The axial flow passage 14a and the radial flow passage 14c form the one-end-side flow passage 321B. The axial flow passage 14a is a flow passage extending along the axial direction. The radial flow passage 14c is a flow passage connected to the downstream end of the axial flow passage 14a and extending in the radial direction.

[0060] As shown in FIG. 9 , sleeve 69 is formed with, in order from the upstream side to the downstream side, a connecting passage 69a, which is an annular groove formed in outer peripheral surface 69fa, a radial passage 69c, and an axial passage 69d. Connecting passage 69a, radial passage 69c, and axial passage 69d constitute one-end-side passage 321B. Connecting passage 69a is formed at a position facing radial passage 14c in the radial direction of main shaft 10. Radial passage 69c is a passage extending along the radial direction. The upstream end of radial passage 69c is connected to connecting passage 69a. Axial passage 69d is a passage extending along the axial direction. The upstream end of axial passage 69d is connected to radial passage 69c. The downstream end of axial passage 69d is a first opening 69fp formed in first end face 69fb.

[0061] As shown in FIG. 9, the spindle cap 10C has, in order from upstream to downstream, a circumferential groove 10fv, a first axial flow passage 10a, a radial flow passage 10b, and a second axial flow passage 10c. The circumferential groove 10fv, the first axial flow passage 10a, the radial flow passage 10b, and the second axial flow passage 10c form the one-end-side flow passage 321B. The circumferential groove 10fv is a groove flow passage formed circumferentially on the second end face 10fb. The portion of the circumferential groove 10fv on the second end face 10fb side is a second opening 10fp. The first axial flow passage 10a is a flow passage extending along the axial direction. The upstream end of the first axial flow passage 10a is connected to the circumferential groove 10fv. The radial flow passage 10b is a flow passage extending along the radial direction. The upstream end of the radial flow passage 10b is connected to the first axial flow passage 10a. The second axial flow passage 10c is a flow passage extending along the axial direction, and an upstream end of the second axial flow passage 10c is connected to a downstream end of the radial flow passage 10b.

[0062] The axial flow passage 69d, the circumferential groove 10fv, and the first axial flow passage 10a form an axial flow passage 321Bb that includes a first opening 69fp and a second opening 10fp. As shown in Fig. 9, in the clamped state, the axial flow passage 69d and the circumferential groove 10fv face each other with a small gap in the axial direction.

[0063] As shown in FIG. 12, when the spindle device 11 transitions from the clamped state to the unclamped state, the cylinder device 15 advances the spindle 10 including the spindle cap 10C, moving the second end face 10fb toward the first end face 69fb. As a result, in the unclamped state, the first end face 69fb and the second end face 10fb abut against each other. In the unclamped state, the rotational phase position of the spindle 10 is controlled and stopped so that the axial flow passage 69d and the first axial flow passage 10a are aligned in the axial direction. By controlling and stopping the rotational phase position of the spindle 10, entering the unclamped state, and supplying air, the axial flow passage 69d and the first axial flow passage 10a are aligned in the axial direction, allowing air to flow smoothly from the upstream side to the downstream side of the axial flow passage 321Bb. When the second end face 10fb advances and abuts against the first end face 69fb, the first end face 69fb is also slightly displaced forward. On the other hand, at least in the unclamped state, the seal material 79 is compressed in the axial direction, and therefore urges the sleeve 69 toward the second end face 10fb. As a result, in the unclamped state, the first end face 69fb and the second end face 10fb of the sleeve 69 are in close contact with each other, which can prevent air from leaking from the axial flow path 321Bb to the outside. Furthermore, because the first end face 69fb and the second end face 10fb are in close contact with each other due to the elastic force of the seal material 79, the amount of wear on the first end face 69fb and the second end face 10fb can be reduced.

[0064] As shown in FIG. 11 , the front inner ring retainer 64 is formed with an axial passage 64a extending along the axial direction. The upstream end of the axial passage 64a is connected to a second axial passage 10c formed in the spindle cap 10C. The spindle body 10E is further formed with, in order from upstream to downstream, an axial passage 10Ea extending along the axial direction and a radial passage 10Eb extending along the radial direction. The upstream end of the axial passage 10Ea is connected to the axial passage 64a. The upstream end of the radial passage 10Eb is connected to the axial passage 10Ea. The axial passage 64a, the axial passage 10Ea, and the radial passage 10Eb form a downstream-side communicating passage 321C.

[0065] As shown in FIG. 8, the downstream end of radial flow path 10Eb, which is the downstream end of downstream-side communication path 321C, is connected to annular path 30Ha. Annular path 30Ha is an annular groove formed around central axis AX on the outer peripheral surface of collet sleeve 30H. As shown in FIGS. 8 and 11, the upstream sides of multiple spindle air supply paths 327 are connected to annular path 30Ha. That is, annular path 30Ha connects multiple spindle air supply paths 327. Air flowing through radial flow paths 10Eb of two downstream-side communication paths 321C flows through annular path 30Ha, allowing it to flow more uniformly into six spindle air supply paths 327. The air that flows into spindle air supply path 327 flows into storage space 10N. The air that flows into storage space 10N becomes a straight flow by flowing through collet gap 20b.

[0066] The second embodiment has the same configuration as the first embodiment, and thus provides the same effects. For example, air supplied to the storage space 10N passes through the collet gap 20b and becomes a straight flow, so that even if the tool is removed from the tapered hole 10T, the occurrence of the suction phenomenon near the central axis AX of the tapered hole 10T can be suppressed. Also, as shown in FIG. 8, the spindle unit 11 has an annular passage 30Ha that connects the upstream sides of the multiple spindle air supply passages 327. The annular passage 30Ha allows the multiple spindle air supply passages 327Since the flow rate of air flowing into the tapered hole 10T can be made more uniform, the flow rate of air flowing through the storage space 10N and passing through each of the plurality of collet gaps 20b to become a straight flow can be made more uniform. Therefore, the flow of air flowing out from each of the plurality of collet gaps 20b is less likely to be biased, and the occurrence of the suction phenomenon near the central axis AX of the tapered hole 10T can be more effectively suppressed. Furthermore, according to the second embodiment, since the air communication passage 321 including the one-end-side flow passage 321B is formed radially outward from the spindle air supply passage 327, the air communication passage 321 can be formed radially inward from the spindle air supply passage 327 of the spindle 10, for example, in the spindle hole 10J of the spindle 10, which can provide a more uniform flow rate of the air. 11 This prevents the configuration from becoming complicated. For example, since it is not necessary to form the air communication passage 321 inside the draw bar 230, it is not necessary to make the draw bar 230 a double-pipe structure. Furthermore, by forming a part of the air communication passage 321 in the front cap 14 and the spindle cap 10C, the front cap 14 and the spindle cap 10C can be easily assembled, and the one-end-side flow passage 321B can be easily formed. Furthermore, by forming the one-end-side flow passage 321B in the spindle housing 3 and the spindle 10, it is not necessary to use another member to form the one-end-side flow passage 321B. Furthermore, according to the second embodiment, as shown in FIG. 12 , the first opening 69fp of the spindle housing 3, which is a non-rotating element, and the second opening 10fp of the spindle 10, which is a rotating element, are opposed to each other, and thus the axial flow passage 321Bb spanning the spindle housing 3 and the spindle 10 can be formed.

[0067] D. Alternatives to the second embodiment: FIG. 13 is a first diagram for explaining another embodiment of the second embodiment. FIG. 14 is a second diagram for explaining another embodiment of the second embodiment. FIG. 13 is a diagram corresponding to FIG. 11 and shows an unclamped state. FIG. 14 is a diagram corresponding to FIG. 12 and shows one-end-side flow path 321B in an unclamped state. In the first embodiment, as shown in FIG. 12, one-end-side flow path 321B has axial flow path 321Bb formed by axial flow path 69d, circumferential groove 10fv, and first axial flow path 10a. However, instead of this, for example, as shown in FIG. 13, it may have radial flow path 421Bb extending in the radial direction. Note that, unlike spindle device 11 of the second embodiment shown in FIG. 11, spindle device 111 shown in FIG. 13 does not have sleeve 69, seal member 79, or presser plate 16. In this embodiment, one-end-side flow passages 321B are formed in first front outer race retainer 61, front cap 14 which is a part of spindle housing 3, spindle cap 10C which is a part of spindle 10, and front inner race retainer 64. Although downstream-side communicating passages 321C formed in spindle cap 10C, front inner race retainer 64, and spindle body 10E which are rotating elements shown in Fig. 13 are branched into two passages by annular groove 10Cd, this is not limitative and three passages may be formed. When there are two downstream-side communicating passages 321C, for example, the downstream-side communicating passages 321C are provided at positions facing each other in the radial direction of spindle 10.

[0068] The front cap 14 of the spindle housing 3 is formed with, in order from upstream to downstream, an axial flow passage 14h extending along the axial direction shown in FIG. 13 and a radial flow passage 14i extending along the radial direction shown in FIG. 14. The downstream end of the axial flow passage 14h is connected to the upstream end of the radial flow passage 14i. The axial flow passage 14h and the radial flow passage 14i form a one-end-side flow passage 321B. The downstream end of the radial flow passage 14i has an inner circumferential surface opening 14k that opens to an inner circumferential surface 14j of the front cap 14. The inner circumferential surface 14j is located forward (toward one end) of the front-side bearing 10A. The inner circumferential surface 14j is also referred to as a one-end-side housing inner circumferential surface 14j.

[0069] The spindle cap 10C of the main shaft 10 is formed with, in order from upstream to downstream, an annular groove 10Cd, a radial passage 10Ce extending along the radial direction, and an axial passage 10Cf extending along the axial direction. The annular groove 10Cd, the radial passage 10Ce, and the axial passage 10Cf together form the one-end-side passage 321B. The annular groove 10Cd is a groove passage formed circumferentially on the outer circumferential surface 10fc of the cap small diameter portion 10Cb. The outer circumferential surface 10fc is also referred to as the one-end-side main shaft outer circumferential surface 10fc. The annular groove 10Cd has an outer circumferential surface opening 10fr that opens radially outward. The upstream end of the radial passage 10Ce is connected to the annular groove 10Cd. The downstream end of the radial passage 10Ce is connected to the axial passage 10Cf. The control device 90 controls and stops the rotational phase position of the spindle 10 so that, in the unclamped state, the radial flow passage 10Ce is positioned radially opposite the inner circumferential surface opening 14k, or so that, when the inner circumferential surface opening 14k is at the 0-degree position, the two radial flow passages 10Ce are positioned at 90-degree and 270-degree positions. The air supply is stopped when the spindle 10 changes from the unclamped state to the clamped state. The radial flow passage 14i, the annular groove 10Cd, and the radial flow passage 10Ce form a radial flow passage 421Bb extending radially in the unclamped state. In this embodiment, even when the spindle 10 shifts slightly forward during the transition from the clamped state to the unclamped state, the cap large-diameter portion 10Ca and the front cap 14 are spaced apart in the axial direction.

[0070] The air flowing through the radial flow passage 421Bb shown in FIG. 14 flows sequentially through the axial flow passage 10Cf, the axial flow passage 64a of the front inner ring retainer 64 shown in FIG. 13, the axial flow passage 10Ea and the radial flow passage 10Eb of the spindle body 10E, and then flows into the spindle air supply passage 327 via the annular passage 30Ha. As shown in FIG. 14, the boundary portion of the radial flow passage 421Bb between the radial flow passage 14i and the annular groove 10Cd is formed by a gap between the inner circumferential surface 14j and the outer circumferential surface 10fc. This gap is part of the annular gap around the center axis AX. Gaps (side gaps) between the inner circumferential surface 14j and the outer circumferential surface 10fc are also formed on both axial sides of the boundary portion of the radial flow passage 421Bb. These side gaps have a flow passage resistance sufficient to prevent the air flowing through the radial flow passage 421Bb from leaking to the outside. The flow passage resistance of these side gaps prevents air from leaking from the radial flow passage 421Bb.

[0071] According to the other embodiment described above, a flow path extending across spindle housing 3, which is a non-rotating element, and spindle 10, which is a rotating element, can be formed as radial flow path 421Bb. Note that spindle device 11 may be provided with both axial flow path 321Bb shown in Fig. 12 and radial flow path 421Bb shown in Fig. 14.

[0072] 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]

[0073] 1, 11... spindle device, 3... spindle housing, 10... spindle, 10a... first axial flow passage, 10b... radial flow passage, 10c... second axial flow passage, 10A... front side bearing, 10B... rear side bearing, 10C... spindle cap, 10Ca... large diameter portion of cap, 10Cb... small diameter portion of cap, 10Cd... annular groove, 10Ce... radial flow passage, 10Cf... axial flow passage, 10 D...Step portion, 10E...Spindle body, 10Ea...Axial flow passage, 10Eb...Radial flow passage, 10F...One end portion, 10H...Spindle cylindrical portion, 10J...Shaft hole, 10M...Spindle cam surface, 10N...Storage space, 10P...Spindle protrusion, 10R...Other end portion, 10T...Tapered hole, 10fb...Second end face, 10fc...Outer peripheral surface, 10fp...Second opening, 10fr...Outer peripheral surface opening, 10fv...Circumferential groove 、12...bearing housing, 14...front cap, 14a, 14h...axial flow path, 14b...recess, 14c, 14i...radial flow path, 14e...fourth end face, 14j...inner peripheral surface, 14k...inner peripheral surface opening, 15...cylinder device, 16...pressure plate, 17...housing body, 18...piston, 19...first coolant flow path, 20...collet chuck, 20a...one end of collet, 20b...collet gap, 20c...other end of collet, 21...collet claw, 21a...claw inclined surface, 21b...first claw cam surface, 21c...collet recess, 21d...second claw cam surface, 22...collet base, 23...collet cylindrical portion, 24...collet tip portion, 25...spool, 24b...inner peripheral convex portion, 26...draw bolt, 26a...bolt inclined surface, 27...draw bolt one end portion, 28...draw bolt other end portion, 30...draw bar, 30A...outer peripheral draw bar, 30D, 30I...large diameter portion, 30F...draw bar one end portion, 30G...guide sleeve, 30H...collet sleeve tube, 30Ha...annular passage, 30R...other end of drawbar, 31H...first rod hole, 32H...second rod hole, 33...disc spring, 34...collar, 35...second air supply passage, 35A...upstream side passage, 35B...downstream side passage, 35C...other end air passage, 35D...one end air passage, 36...inner piping, 36A...one end of piping, 36B...other end of piping, 37...push rod, 38...third coolant passage, 40...electric motor, 41...rotor, 42...stator, 46...rotating jaw Inlet, 47...fixed joint, 47a...fourth coolant passage, 48...second coolant passage, 49...fifth coolant passage, 50...sixth coolant passage, 55...upstream air supply passage, 56...downstream air supply passage, 61...first front outer ring retainer, 62...second front outer ring retainer, 64...front inner ring retainer, 64a...axial passage, 65...closure plate, 66...rear inner ring retainer, 67...first rear outer ring retainer, 68...second rear outer ring retainer, 69...sleeve, 69a...connecting passage, 69b... Convex part , 69c… Radial flow passage , 69d… Axial flow path, 69fa... outer peripheral surface, 69fb... first end surface, 69fp... first opening, 69e... third end surface, 71... coil spring, 79... sealing material, 82... bolt, 85... opening, 90... control device, 92... air supply device, 93... hydraulic device, 95... coolant supply device, 111... spindle device, 120... air supply path, 125... third air supply path, 126... sixth air supply path, 130...coolant flow path, 142...step surface, 144...step surface, 146...bolt, 148...preload spring, 155...fourth air supply path, 156...spindle air supply path, 230...draw bar, 234...front side member, 235...rear side member, 320...air supply path, 321...air communication path, 321A...upstream side communication path, 321B...one end side flow path, 321Bb...axial direction flow path 、3 21C...Downstream communication passage, 327...Main spindle air supply passage 、3 31...Upstream end portion, 337...Push rod, 338...Rod coolant passage, 355...Upstream air supply passage, 356...Downstream air supply passage 355, 382H...Rod hole, 421Bb...Radial passage, AX...Center axis, R2...Area

Claims

1. A spindle device, A spindle housing; a spindle rotatably supported by the spindle housing, the spindle having a tapered hole located at one end and a tool detachably attached thereto, and a spindle cylinder portion located closer to the other end than the tapered hole and communicating with the tapered hole; a collet chuck disposed within the spindle cylindrical portion and configured to grip the tool; a draw bar that is disposed within the spindle cylindrical portion, is connected to the other end of the collet of the collet chuck, and moves the collet chuck back and forth along the axial direction of the spindle, the spindle comprises a spindle body rotatably supported by the spindle housing, and a collet sleeve disposed on an inner peripheral side of the spindle body, the collet sleeve having the spindle cylindrical portion on the inner peripheral side, The collet chuck is a plurality of claw portions that grip the tool, the plurality of claw portions being arranged in a circumferential direction around a central axis of the spindle; a plurality of collet gaps extending from one end of an annular collet forming one end toward the other end of the spindle and forming a flow path for guiding air to the tapered hole, the collet gaps being gaps between the respective claw portions of the plurality of claw portions; a collet cam surface; the collet sleeve has a plurality of spindle air supply passages formed at intervals from one another in the circumferential direction, each of the spindle air supply passages having a plurality of spindle air supply passages extending along a radial direction, the spindle cylindrical portion has a storage space in which the other end of the collet is stored in a clamped state, a partition surface that partitions the storage space has a cam surface that comes into contact with the collet cam surface when the collet chuck moves forward; the spindle device further includes an annular passage formed between the spindle body and the collet sleeve, the annular passage connecting upstream sides of the plurality of spindle air supply passages, a spindle device configured so that, in an unclamped state, air flows sequentially through the annular passage, the plurality of spindle air supply passages, the storage space, and the collet gap, and is supplied to the tapered hole.

2. The spindle device according to claim 1, a spindle device, wherein a relative position of each of the plurality of collet gaps with respect to each of the plurality of spindle air supply passages is the same as each other.

3. The spindle device according to claim 2, the number of the plurality of collet gaps is the same as the number of the plurality of spindle air supply passages, a spindle device, wherein the plurality of collet gaps are arranged at equal intervals, and the plurality of spindle air supply passages are arranged at equal intervals.

4. The spindle device according to claim 3, a spindle device in which the phase positions of the plurality of spindle air supply passages and the phase positions of the plurality of collet gaps coincide with each other.

5. The spindle device according to claim 1, further comprising: a biasing member that biases the draw bar in a direction away from the tapered hole along the axial direction; a cylinder device that pushes the draw bar toward the tapered hole in the unclamped state.

6. The spindle device according to claim 1, further comprising: an inner pipe disposed within the draw bar, the inner pipe having a pipe one end portion forming one end of the inner pipe and a pipe other end portion closer to the other end of the spindle than the pipe one end portion; a piping air supply passage disposed outside the inner piping and extending from one end of the piping to the other end of the piping; an air flow path at another end of the piping, the air flow path being disposed adjacent to the other end of the piping and configured to allow air to flow into the piping air supply path, the air flowing inward in the radial direction of the inner piping; an air flow path disposed adjacent to one end of the piping for allowing air to flow out from the piping air supply path, the air flow path being configured to allow air to flow radially outward from the inner piping; a guide sleeve disposed between the spindle body and the draw bar and adjacent to the collet sleeve in the axial direction; a third air supply passage formed by a gap between the guide sleeve and the draw bar, the third air supply passage having one end communicating with the air flow passage; a guide sleeve flow path formed at one end of the guide sleeve and extending along a radial direction of the guide sleeve, the guide sleeve flow path communicating with the third air supply path; a collet sleeve flow path as the annular path formed between the spindle body and the collet sleeve, the other end side of which communicates with the guide sleeve flow path and one end side of which communicates with the plurality of spindle air supply paths; a coolant flow path disposed inside the inner piping.

7. The spindle device according to claim 1, further comprising: an air communication passage formed radially outward of the spindle air supply passage, which supplies air from outside to the spindle air supply passage; a front-side bearing arranged at a position close to the one end of the main shaft in the axial direction and rotatably supporting the main shaft, a spindle device, wherein the air communication passage is a one-end-side flow path located closer to the one end than the front-side bearing in the axial direction, and the one-end-side flow path is formed in the spindle housing and the spindle.

8. The spindle device according to claim 7, the spindle housing has a first end surface in which a first opening constituting the one-end-side flow path is formed, the main shaft has a second end surface in which a second opening constituting the one-end-side flow path is formed, the second end surface facing the first end surface in the axial direction, The one-end-side flow passage includes the first opening and the second opening and has an axial flow passage extending in the axial direction.

9. The spindle device according to claim 8, the spindle housing includes a sleeve that surrounds the spindle around the axial direction, the sleeve has an outer circumferential surface, the first end surface, and a third end surface protruding from the outer circumferential surface, the spindle housing further has a fourth end surface facing the third end surface in the axial direction, The spindle device further includes: a sealant disposed between the third end surface and the fourth end surface, the sealant being compressed in the axial direction in the unclamped state to urge the sleeve toward the second end surface.

10. The spindle device according to claim 9, The main shaft further includes a spindle cap that forms the tapered hole, the spindle housing further includes a front cap that forms one housing end of the spindle housing, The one end side flow path is formed in the spindle cap and the front cap.

11. The spindle device according to claim 10, The main shaft is a cap small diameter portion located radially inside the spindle housing; a cap large diameter portion located closer to the other end than the cap small diameter portion in the axial direction, the cap large diameter portion having an outer diameter larger than that of the cap small diameter portion; The second end surface is formed on the large diameter portion of the cap.

12. The spindle device according to claim 8, further comprising: a biasing member that biases the draw bar in a direction away from the tapered hole along the axial direction; a cylinder device that pushes the draw bar toward the tapered hole in the unclamped state, In the clamped state, the first end surface and the second end surface are spaced apart from each other, a spindle device that causes the second end surface to abut against the first end surface in the unclamped state;

13. The spindle device according to claim 10, further comprising: a main spindle device having a presser plate attached to the front cap, the presser plate having the fourth end surface.

14. The spindle device according to any one of claims 7 to 13, the spindle housing has a first-end-side housing inner circumferential surface on which an inner circumferential surface opening that constitutes the first-end-side flow path is formed, the main shaft has a one-end-side outer circumferential surface on which an outer circumferential surface opening that constitutes the one-end-side flow path is formed, In the unclamped state, the outer peripheral surface opening is disposed at a position opposite to the inner peripheral surface opening in the radial direction, the one-end-side flow path includes the inner circumferential surface opening and the outer circumferential surface opening, and has a radial flow path extending in the radial direction in the unclamped state.

Images