阅读说明：本技术 主轴装置 (Spindle device ) 是由 室田真弘 于 2019-07-22 设计创作，主要内容包括：本发明提供一种主轴装置(20),其具备主轴壳体(24)、能够旋转地支撑在主轴壳体(24)的内部的主轴轴体(22)、具有供主轴壳体(24)沿主轴轴体(22)的轴向插通的插通孔(26H)的主轴安装台(26)、以及覆盖主轴安装台(26)的安装台罩(29)。在安装台罩(29)的内部设有用于调节安装台罩(29)的内部的温度的温度调节部(80)。(A spindle device (20) is provided with a spindle housing (24), a spindle shaft body (22) rotatably supported inside the spindle housing (24), a spindle mount (26) having an insertion hole (26H) through which the spindle housing (24) is inserted in the axial direction of the spindle shaft body (22), and a mount cover (29) covering the spindle mount (26). A temperature adjusting part (80) for adjusting the temperature inside the mounting table cover (29) is arranged inside the mounting table cover (29).)

1. A spindle device is characterized by comprising:

a spindle housing;

a spindle shaft body rotatably supported inside the spindle housing;

a spindle mount having an insertion hole through which the spindle housing is inserted in an axial direction of the spindle shaft;

a mount cover covering the spindle mount; and

and a temperature adjusting unit provided inside the mount table cover and configured to adjust a temperature inside the mount table cover.

2. The spindle device according to claim 1,

the temperature adjusting unit has a heat sink fixed to an outer peripheral surface of the spindle mount, and a pipe through which a refrigerant flows is attached to the heat sink.

3. Spindle device according to claim 1 or 2,

a gas supply pipe for supplying compressed gas into the mount table cover is connected to the mount table cover.

4. The spindle device according to claim 3,

a part of the seal gas supplied to the gap between the rotating member rotatably disposed on the surface of the spindle housing on the one end side of the spindle shaft body and the cover member covering the outer peripheral surface of the rotating member flows into the gas supply pipe.

5. Spindle device according to claim 1 or 2,

a cooling passage for cooling the supplied gas is formed in the spindle mount, and the gas flowing through the cooling passage is supplied to a gas supply destination.

6. The spindle device according to claim 5,

the cooling flow path includes:

a first communicating portion communicating with the gas inlet; and

and a second communicating portion which is formed wider than the first communicating portion and communicates the first communicating portion with the gas outlet.

7. A spindle device according to claim 5 or 6,

the gas supply destination is a gap between a rotating member provided rotatably on a surface of the spindle housing on one end side of the spindle shaft body and a cover member covering an outer peripheral surface of the rotating member.

8. A spindle device according to claim 5 or 6,

the gas supply destination is a bearing that rotatably supports the spindle shaft body.

9. A spindle device according to any one of claims 2 to 8,

the heat dissipation plate has a first heat dissipation plate and a second heat dissipation plate arranged with a gap with respect to the first heat dissipation plate,

the second heat sink is disposed closer to one end side of the spindle shaft than the first heat sink, and a rotating member that is rotatable in conjunction with the spindle shaft is provided at one end side of the spindle shaft.

10. The spindle device according to claim 9,

the gap extends in a direction intersecting the axial direction of the spindle shaft body.

11. Spindle device according to claim 9 or 10,

the second heat dissipation plate has a larger surface area than the first heat dissipation plate.

12. A spindle device according to any one of claims 9 to 11,

the first and second heat radiating fins are fixed to the spindle mounting base at one position.

Technical Field

The present invention relates to a spindle device used in a lathe (machine tool) that machines a machining object with a tool.

Background

Heat generated during machining of a workpiece may cause thermal deformation of a spindle housing or the like that houses a spindle shaft body, and the machining accuracy may be reduced due to the thermal deformation. Therefore, a countermeasure to suppress thermal deformation becomes important.

For example, japanese patent application laid-open publication No. 2011-240428 discloses the following cooling structure: the housing and the main shaft are provided with coolant passages, respectively, and the main shaft and the bearing are cooled by supplying and receiving coolant between the coolant passage in the housing and the coolant passage in the main shaft and flowing the coolant into the main shaft.

However, in the cooling structure of japanese patent application laid-open No. 2011-240428, the heat generated by the bearing is not transmitted to the housing, although it is cooled. When the amount of heat transferred to the casing is locally different in the casing, thermal deformation is likely to occur due to a temperature difference generated between the local parts of the casing. In recent years, machining of a workpiece is sometimes controlled on a nanometer scale, and in this case, even if the amount of thermal deformation occurring during machining is small, the reduction in machining accuracy is significantly inclined. Therefore, a countermeasure for suppressing the reduction in the machining accuracy is strongly required.

Disclosure of Invention

Therefore, an object of the present invention is to provide a spindle device capable of suppressing a reduction in machining accuracy.

An aspect of the present invention is a spindle device including: a spindle housing; a spindle shaft body rotatably supported inside the spindle housing; a spindle mount having an insertion hole through which the spindle housing is inserted in an axial direction of the spindle shaft; a mount cover covering the spindle mount; and a temperature adjusting unit provided inside the mount table cover and configured to adjust a temperature inside the mount table cover.

According to the present invention, the inside of the mount table cover can be cooled by the temperature adjusting portion. Therefore, it is possible to reduce the temperature difference between the spindle mount covered by the mount cover, the spindle housing inserted through the insertion hole of the spindle mount, and the spindle shaft supported inside the spindle housing, and the local temperature difference of the components. Therefore, the thermal deformation of the member covered by the mount cover can be suppressed. As a result, a reduction in machining accuracy can be suppressed.

The above objects, features and advantages will become more readily apparent from the following description of the embodiments with reference to the accompanying drawings.

Drawings

Fig. 1 is a schematic view showing a lathe according to the present embodiment.

Fig. 2 is a diagram showing a cross section of the spindle device of fig. 1.

Fig. 3 is a schematic view showing a cross section of a spindle device according to modification 1.

Fig. 4 is a schematic view showing a cross section of a spindle device according to modification 2.

Fig. 5 is an enlarged view of a part of the spindle device according to modification 3.

Fig. 6 is a view showing the spindle device according to modification 5 from the same perspective as fig. 1.

Detailed Description

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, taking preferred embodiments as examples.

[ embodiment ]

Fig. 1 is a diagram showing a lathe 10. The lathe 10 machines an object to be machined by using a tool, and includes a base 12, a spindle support 14, a table support 16, a table 18, and a spindle device 20.

The spindle support portion 14 is provided on the base chassis 12, and supports the spindle device 20 movably in the left-right direction with respect to the base chassis 12. The direction (axial direction) in which the spindle shaft body 22 in the spindle device 20 extends is defined as a front-rear direction, a direction perpendicular to the axial direction within a plane parallel to a mounting surface F on which the spindle device 20 is mounted is defined as a left-right direction, and a direction perpendicular to the mounting surface F and the axial direction is defined as a vertical direction. The lower direction is the direction in which gravity acts. One end of the spindle shaft body 22 of the spindle device 20, on which the chuck unit 30 is provided, is defined as a front side, and the other end of the spindle shaft body 22 is defined as a rear side.

The spindle support portion 14 includes: a first sliding portion 14a provided on the base chassis 12 in the left-right direction; a spindle moving table 14b movable along the first slide portion 14 a; and a first driving mechanism, not shown, for driving the spindle moving stage 14 b.

The first drive mechanism includes a motor and a member such as a ball screw that converts a rotational force of the motor into a linear motion. The spindle moving table 14b is moved along the first slide portion 14a by the first driving mechanism, and thereby the spindle device 20 provided on the spindle moving table 14b is moved in the left-right direction with respect to the base chassis 12.

The table support portion 16 is provided on the base 12, and supports the table 18 to be movable in the front-rear direction with respect to the base 12. The table support portion 16 includes a second slide portion 16a provided on the base chassis 12 in the front-rear direction, and a second drive mechanism, not shown, that drives the table 18 movable along the second slide portion 16 a.

The second driving mechanism includes a motor and a member such as a ball screw for converting a rotational force of the motor into a linear motion. By the second driving mechanism, the table 18 is moved in the front-rear direction with respect to the base chassis 12 via the second slide portion 16 a. The table 18 may be rotatable about a vertical axis as a rotation axis.

In the present embodiment, the object is held by the chuck section 30 of the spindle device 20, and the tool is held by the table 18. However, the tool may be held in the chuck section 30 of the spindle device 20, and the object may be held in the table 18.

Fig. 2 is a view showing a cross section of the spindle device 20 of fig. 1. The spindle device 20 of the present embodiment is used for controlling machining of a machining object in a nanometer unit, for example, by rotatably holding the machining object. The spindle device 20 includes a spindle shaft body 22, a spindle housing 24, a spindle mount 26, a cover member 28, and a mount cover 29 as main components.

The spindle shaft body 22 is a cylindrical member and has a cylindrical through hole 22H penetrating in the axial direction. In the example shown in fig. 2, the through-hole 22H includes a front-side through-hole 22Ha and a rear-side through-hole 22Hb having a smaller diameter than the front-side through-hole 22 Ha. A chuck unit 30 is provided on one end side (front side) of the spindle shaft body 22, and a motor 40 is provided on the other end side (rear side).

The chuck unit 30 is a rotary member provided at one end of the spindle shaft body 22 so as to be rotatable on the front surface of the spindle housing 24 in conjunction with the rotation of the spindle shaft body 22, and is used to attach and detach a processing object in the present embodiment. In fig. 1, the chuck section 30 is formed in a disk shape, but may have another shape. The chuck unit 30 includes a base 30a fixed to the front side of the spindle shaft body 22, and a suction pad 30b detachably attached to the base 30 a. An opening OP is formed in the suction surface of the suction pad 30 b. The base 30a and the suction pad 30b are formed with a communication path 30c that communicates the opening OP with one end of the through hole 22H of the spindle shaft body 22. In the chuck unit 30, air outside the chuck unit 30 is sucked from the opening OP to the through hole 22H through the communication path 30c by a vacuum pump not shown, whereby the object is held in close contact with the suction surface.

The motor 40 is a drive source of the spindle shaft body 22, and includes a motor housing 40a attached to the rear side of the spindle housing 24, a rotor 40b provided in the motor housing 40a, and a stator 40 c. The main shaft body 22 is fixed to the rotor 40 b. Therefore, the main shaft body 22 rotates in conjunction with the rotation of the rotor 40 b.

The spindle housing 24 has a substantially cylindrical housing main body 24a and a rear side housing cover 24 b. The case body 24a is provided with an annular flange portion 50 protruding outward from the outer peripheral surface of the case body 24 a. The flange portion 50 may be formed integrally with the case main body 24a, or may be fixed to the case main body 24a by a predetermined fixing member independently of the case main body 24 a.

A rear side case cover 24b is provided on the rear side of the case main body 24a so as to cover the opening on the rear side of the case main body 24a, and the rear side case cover 24b is detachably provided. A motor case 40a of the motor 40 is fixed to a surface (rear end surface) side of the rear case cover 24 b.

A substantially cylindrical shaft body arrangement space is formed between the rear case cover 24b and the case main body 24a so as to penetrate in the front-rear direction. The spindle shaft body 22 is disposed in the shaft body disposition space, and the spindle shaft body 22 disposed in the shaft body disposition space is rotatably supported via a bearing 60.

In the present embodiment, the bearing 60 includes a thrust bearing 60a and a radial bearing 60 b. The thrust bearings 60a are provided on the left and right sides of the main shaft body 22, respectively, and the radial bearings 60b are provided in front of and behind the main shaft body 22 at positions closer to the rear side of the main shaft body 22 than the thrust bearings 60 a. The bearing 60 may be a hydrostatic bearing or a rolling bearing. However, when the machining of the object to be machined is controlled on a nanometer scale as described above, it is preferable to use a hydrostatic bearing.

The spindle mount 26 is mounted on a mounting surface F (fig. 1) of the spindle moving table 14 b. The spindle mount 26 has an insertion hole 26H through which the spindle housing 24 is inserted in the axial direction of the spindle shaft 22. The front side of the spindle housing 24 inserted into the insertion hole 26H is fixed to the front side of the spindle mount 26 via the flange portion 50 provided on the housing main body 24a, and the rear side of the spindle housing 24 is supported via the support member 70 provided on the rear side of the spindle mount 26.

Specifically, the flange portion 50 is detachably fixed to the front side of the spindle mount 26 (the side opening of the insertion hole 26H) by a rod-shaped fastening member such as a bolt. On the other hand, the support member 70 supports the spindle housing 24 on the rear side of the spindle mount 26 (the other side opening side of the insertion hole 26H). That is, the spindle housing 24 is supported at both ends from the front and rear of the spindle housing 24 and is held by the spindle mount 26.

The cover member 28 covers the front surface of the flange portion 50, the outer peripheral surface of the housing main body 24a extending forward from the front surface, and a part of the outer peripheral surface of the chuck portion 30. Although the cover member 28 covers a part of the outer peripheral surface of the chuck section 30, the entire outer peripheral surface may be covered, and at least a part of the outer peripheral surface of the chuck section 30 may be covered.

The cover member 28 is provided with a gas flow passage 28a through which a seal gas for sealing the seal portion flows. The seal portions are gaps between the chuck portion 30 and the cover member 28 and between the chuck portion 30 and the housing main body 24 a. The gas may be compressed to a predetermined pressure. Specifically, for example, air may be mentioned. By supplying the seal portion with the seal gas, it is possible to prevent debris generated during processing of the object to be processed, a cooling medium used during processing, and the like from entering the interior (shaft body arrangement space) of the spindle housing 24 through the gap. The seal gas flowing through the seal portion is discharged to the outside from the front side of the spindle device 20 or the like.

A flow path for the refrigerant, not shown, through which the refrigerant flows is formed in the cover member 28, and the temperature of the cover member 28 is adjusted by the refrigerant flowing through the flow path for the refrigerant. The refrigerant is, for example, water or compressed air.

As shown in fig. 1 and 2, the mount cover 29 is a cover member that covers the spindle mount 26. The mount cover 29 is fixed to the spindle moving base 14b (see fig. 1) in a state of covering substantially the entire spindle mount 26. A part of the front side of the spindle housing 24 inserted into the insertion hole 26H of the spindle mount 26 is exposed to the outside from the mount cover 29.

A temperature adjusting unit 80 (see fig. 1) for adjusting the temperature inside the mount table cover 29 is provided inside the mount table cover 29 and on both the left outer surface and the right outer surface of the outer peripheral surface of the spindle mount table 26. Each temperature adjustment unit 80 has a heat radiation plate 82 fixed to the outer surface of the spindle mount 26.

In the present embodiment, the heat sink 82 includes first fins 82a and second fins 82b arranged with a gap from the first fins 82 a. The second heat radiation fins 82b are arranged on the front side of the first heat radiation fins 82 a. The gap between the first heat radiation fin 82a and the second heat radiation fin 82b extends in a direction intersecting the axial direction of the spindle shaft body 22. In the example shown in fig. 1, the direction in which the gap extends is substantially orthogonal to the axial direction of the spindle shaft body 22.

The pipe 84 is attached to the heat sink 82. The pipe 84 is a pipe for circulating the refrigerant. In the present embodiment, the refrigerant is a liquid such as water. But may also be a gas. The pipe 84 penetrates the mount cover 29, and has a cover inner pipe portion 84a disposed inside the mount cover 29 and a cover outer pipe portion 84b disposed outside the mount cover 29.

The cover inner pipe portion 84a is fixed to the heat dissipation plate 82 by a predetermined fixing member. A circulation pump 86 is provided at the cover outer pipe portion 84 b. In the example shown in fig. 1 and 2, the left-side pipe 84 and the right-side pipe 84 of the spindle mount 26 are not connected to each other and form a single circulation path, but the left-side pipe 84 and the right-side pipe 84 may be connected to each other and form a single circulation path.

The coolant is circulated by the circulation pump 86 inside the pipe 84 (the cover inner pipe portion 84a and the cover outer pipe portion 84b), and at least the spindle mount 26 covered by the mount cover 29 is cooled by the coolant. Cooling passages 26a (see fig. 2) for cooling the seal gas are formed on both the left and right sides of the spindle mount 26.

A hose 88a of a compressor 88 (see fig. 2) provided outside the mount cover 29 is connected to an inlet of the cooling passage 26 a. On the other hand, the flow path 28a (see fig. 2) formed in the cover member 28 is connected to the outlet of the cooling flow path 26a via the communication pipe 89. Therefore, the seal gas flowing through the cooling passage 26a passes through the communication pipe 89 and the passage 28a in this order, and is supplied to the gap between the chuck unit 30 and the cover member 28 to which the gas is supplied.

A gas supply pipe 90 for supplying a sealing gas into the mount cover 29 is connected to the mount cover 29. The flow path 28b (see fig. 2) formed in the cover member 28 is connected to the inlet of the gas supply pipe 90.

The flow path 28b is a flow path for supplying a part of the sealing gas supplied to the gap between the chuck unit 30 and the cover member 28 to the gas supply pipe 90. In the present embodiment, one end side of the flow path 28b opens to the gap between the chuck section 30 and the cover member 28, and the other end side of the flow path 28b opens to the outer peripheral surface of the cover member 28. Further, since the seal gas supplied to the seal portion is discharged to the outside of the spindle housing 24, the gas supply pipe 90 may be connected to a discharge path, not shown, provided in the spindle housing 24.

Next, the flow of the seal gas will be described with reference to fig. 1 and 2. In the spindle device 20 of the present embodiment, the seal gas is output from the compressor 88. When the seal gas is output from the compressor 88, the seal gas flows into the cooling passage 26a formed in the spindle mount 26 through the hose 88a of the compressor 88 and flows through the cooling passage 26 a.

The seal gas flowing out of the cooling passage 26a flows into the passage 28a formed in the cover member 28 through the communication pipe 89, and flows into the gap between the chuck unit 30 and the cover member 28 through the passage 28 a. Part of the seal gas flowing to the gap is discharged from the front side of the spindle device 20 to the outside, and the other part of the seal gas flows into the flow path 28b formed in the cover member 28.

The seal gas flowing into the flow path 28b flows into the gas supply pipe 90 through the flow path 28b, flows through the gas supply pipe 90, and then flows into the mount cover 29. The seal gas flowing into the mount cover 29 generates convection inside the mount cover 29, and a part of the seal gas is discharged to the outside from the discharge port of the mount cover 29. The discharge port may be a slit formed between the mount cover 29 and the spindle housing 24, or may be a through hole provided in the mount cover 29.

[ modified example ]

The above embodiments have been described as examples of the present invention, but the technical scope of the present invention is not limited to the scope described in the above embodiments. Of course, various modifications and improvements can be made to the above-described embodiments. The present invention can be embodied in other forms that are obvious from the description of the claims and that can be modified or improved. The following describes an example in which modifications or improvements are made to the above-described embodiments.

(modification 1)

Fig. 3 is a schematic view showing a spindle device 20 according to modification 1. In fig. 3, the same components as those described in the above embodiment are denoted by the same reference numerals, and the components of the above embodiment that have been described are appropriately omitted.

In the spindle device 20 according to modification 1, the gas supply pipe 90 is connected to a dedicated compressor 92 that supplies compressed gas into the mount cover 29, and the compressed gas that has flowed into the gas supply pipe 90 from the compressor 92 is supplied into the mount cover 29. As described above, as in the above embodiment, the compressed gas supplied to the inside of the mount cover 29 may not be the seal gas.

(modification 2)

Fig. 4 is a schematic view showing a spindle device 20 according to modification 2. In fig. 4, the same components as those described in the above embodiment are denoted by the same reference numerals, and the components of the above embodiment that have been described are appropriately omitted.

In the spindle device 20 according to modification 2, the bearing 60 is a hydrostatic bearing, and the spindle housing 24 (housing main body 24a) is provided with a flow passage 60d for supplying a bearing gas to the bearing 60. The gas for the bearing may be a compressed gas that compresses a gas such as air to a predetermined pressure, or may be compressed at a pressure higher than that of the seal gas. The supply unit 94 for supplying the gas for the bearing is connected to an inlet of the cooling passage 26b formed in the spindle mounting table 26 via a communication passage 96, and an outlet of the cooling passage 26b is connected to the passage 60 d.

In the casing main body 24a of fig. 4, a flow path connecting the radial bearing 60b and the cooling flow path 26b is omitted for convenience of explanation.

In the spindle device 20 of modification 2, the bearing gas output from the supply unit 94 flows into the cooling passage 26b through the communication passage 96, flows through the cooling passage 26b, and the bearing gas flowing out of the cooling passage 26b is supplied to the bearing 60 through the passage 60 d. The bearing gas supplied to the bearing 60 flows from the bearing 60 to the shaft body arrangement space, and functions as a support body for the main shaft body 22. The bearing gas flowing through the shaft body arrangement space is discharged to the outside through a discharge path, not shown, formed in the spindle housing 24.

In this way, the cooling passage 26b for cooling the bearing gas may be formed in the spindle mount 26, and the bearing gas flowing through the cooling passage 26b may be supplied to the bearing 60 as a gas supply destination.

(modification 3)

Fig. 5 is an enlarged view of a part of the spindle device 20 according to modification 3. In fig. 5, the same components as those described in the above embodiment are denoted by the same reference numerals, and the components of the above embodiment described above are appropriately omitted.

In the spindle device 20 according to modification 3, a cooling passage 26c is provided instead of the cooling passage 26a according to the above embodiment. The cooling flow path 26c includes a first communicating portion 100 communicating with the inlet port, and a second communicating portion 102 communicating the first communicating portion 100 with the outlet port. The second communicating portion 102 is formed wider than the first communicating portion 100. That is, the second communicating portion 102 is larger than the first communicating portion 100 in the cross-sectional area in the direction orthogonal to the flow path direction of the gas flowing through the cooling flow path 26 c.

By providing the space in which the rear side of the cooling flow path 26c is wider than the front side in this manner, the compressed gas flowing from the first communicating portion 100 to the second communicating portion 102 adiabatically expands, and the temperature of the compressed gas is likely to decrease. Therefore, the gas flowing through the cooling passage 26c can be cooled more than in the case of the above embodiment.

Further, in modification 3, the wall surface surrounding the second communicating portion 102 is formed with irregularities. Therefore, the surface area of the wall surface is larger than that in the case where the irregularities are not present, and the gas flowing through the cooling passage 26c can be cooled more. However, the wall surface surrounding the second communicating portion 102 may not be formed with the irregularities. The wall surface surrounding the second communicating portion 102 is a wall surface forming a partition wall of the spindle mount 26 of the second communicating portion 102.

In the example shown in fig. 5, the second communicating portion 102 extends substantially straight in the axial direction of the main shaft body 22, but may have a curved portion such as a meandering portion. When the second communicating portion 102 has a curved portion, the distance from the first communicating portion 100 to the outlet can be increased as compared with the case where the second communicating portion extends substantially straight, and the gas flowing in the cooling passage 26c can be cooled more.

In the example shown in fig. 5, the cross-sectional area of the second communication portion 102 in the direction perpendicular to the flow path direction of the gas flowing through the cooling flow path 26c is substantially constant, but may not be constant. For example, the cross-sectional area of the second communicating portion 102 in the direction orthogonal to the flow path direction of the gas flowing through the cooling flow path 26c may be increased as going from the first communicating portion 100 to the outlet.

(modification 4)

The shape of the first fins 82a is the same as that of the second fins 82b in the above embodiment, but may be different. The size of the first fins 82a is the same as that of the second fins 82b in the above embodiment, but may be different.

Further, the heat transferred from the inside of the spindle housing 24 to the spindle housing 24 is easily transferred from the flange portion 50 fixed to the spindle housing 24, and the spindle mount 26 tends to have a temperature gradient in which the temperature on the front side is higher than the temperature on the rear side. Therefore, the surface area of the second fin 82b is preferably larger than the surface area of the first fin 82 a. In this way, even if there is a temperature gradient in the front-rear direction of the spindle mount 26, the temperature gradient occurring in the front-rear direction can be alleviated.

In order to easily reduce warpage of the heat sink 82 due to a temperature difference between the spindle mount 26 and the heat sink 82, the first heat sink 82a and the second heat sink 82b are preferably fixed to the spindle mount 26 at one location.

(modification 5)

In the above embodiment, the heat dissipation plate 82 is divided into two pieces, i.e., the first heat dissipation fin 82a and the second heat dissipation fin 82 b. However, as illustrated in fig. 6, the heat dissipation plate 82 may be divided into four first to fourth heat dissipation fins 82a to 82 d. Further, although not shown, the heat dissipation plate 82 may be divided into three, five or more, or may be unified into one.

(modification 6)

The above-described embodiments and the above-described modifications may be arbitrarily combined within a range not inconsistent with each other.

[ technical idea ]

The following describes technical ideas that can be grasped from the above-described embodiments and modifications.

The spindle device 20 includes: a spindle housing 24; a spindle shaft body 22 rotatably supported inside the spindle housing 24; and a spindle mount 26 having an insertion hole 26H through which the spindle housing 24 is inserted in the axial direction of the spindle shaft 22.

The spindle device 20 includes a mount cover 29 covering the spindle mount 26, and a temperature adjusting unit 80 for adjusting the temperature inside the mount cover 29 is provided inside the mount cover 29.

In the spindle device 20, the temperature adjusting unit 80 can cool the inside of the mount cover 29. Therefore, heat generation of the spindle mount 26 covered by the mount cover 29, the spindle housing 24 inserted into the insertion hole 26H of the spindle mount 26, or the spindle shaft body 22 supported inside the spindle housing 24 can be reduced. Therefore, a reduction in machining accuracy due to thermal deformation of the spindle mount 26, the spindle housing 24, and the spindle shaft body 22 can be suppressed.

The temperature adjusting unit 80 may have a heat sink 82 fixed to the outer peripheral surface of the spindle mount 26, and a pipe 84 through which a refrigerant flows may be attached to the heat sink 82.

In this way, the heat generated by the spindle mount 26 can be dissipated by the heat dissipating plate 82, and the inside of the mount cover 29 can be cooled by the refrigerant. Therefore, heat generation of the spindle mount 26, the spindle housing 24, or the spindle shaft 22 is more easily reduced.

A gas supply pipe 90 for supplying compressed gas into the mount cover 29 may be connected to the mount cover 29.

In this way, convection can be generated inside the mount cover 29 by the compressed gas. Therefore, the inside of the mount cover 29 can be cooled over the entire inside so that the temperature difference in the inside is smaller than in the case where the compressed gas is not supplied to the inside of the mount cover 29.

Part of the seal gas supplied to the gap between the rotary member 30 and the cover member 28 may flow into the gas supply pipe 90, wherein the rotary member 30 is rotatably provided on the surface of the spindle housing 24 on the one end side of the spindle shaft body 22, and the cover member 28 covers the outer peripheral surface of the rotary member 30.

In this way, the seal gas that seals the gap between the rotating member 30 and the cover member 28 can be used as the compressed gas for generating convection inside the mount cover 29. Therefore, the amount of gas consumed can be significantly reduced as compared with the case where the compressed gas and the seal gas for causing convection in the interior of the mount cover 29 are separately used. Therefore, the inside of the mount cover 29 can be efficiently cooled.

The spindle mount 26 may be provided with cooling passages 26a to 26c for cooling the supplied gas, and the gas flowing through the cooling passages 26a to 26c may be supplied to the gas supply destination.

In this way, the gas flowing through the cooling passages 26a to 26c of the spindle mount 26 covered by the mount cover 29 can be cooled by the temperature adjusting unit 80, and the cooled gas can be supplied to the gas supply destination. Therefore, heat generation at the gas supply destination and the paths from the cooling channels 26a to 26c to the gas supply destination can be reduced. Further, the reduction in the machining accuracy due to the thermal deformation can be further suppressed.

The cooling channel 26c may include: a first communicating portion 100 communicating with an inlet of gas; and a second communicating portion 102 formed wider than the first communicating portion 100 and communicating the first communicating portion 100 with the outlet port of the gas.

Thus, the compressed gas flowing from the first communicating portion 100 to the second communicating portion 102 adiabatically expands, and the temperature of the compressed gas is likely to decrease. Therefore, the gas flowing through the cooling passage 26c can be further cooled.

The gas supply destination may be a gap between the rotating member 30 and the cover member 28, the rotating member 30 being rotatably provided on the surface of the spindle housing 24 on the one end side of the spindle shaft body 22, and the cover member 28 covering the outer peripheral surface of the rotating member 30. In this way, the sealing gas for sealing the gap can be supplied in a cooled state.

The gas supply destination may be a bearing that rotatably supports the spindle shaft body 22. In this way, the gas for the hydrostatic bearing can be supplied in a state in which the gas for the hydrostatic bearing is cooled.

The heat sink 82 may include first heat radiation fins 82a and second heat radiation fins 82b arranged with a gap from the first heat radiation fins 82a, and the second heat radiation fins 82b may be arranged closer to one end side of the spindle shaft body 22 than the first heat radiation fins 82a, wherein the one end side of the spindle shaft body 22 is provided with the rotating member 30 that is rotatable in conjunction with the spindle shaft body 22.

In this way, even if a temperature gradient is generated on the other end side of the one end side of the spindle shaft body 22 of the spindle mount 26, the temperature gradient generated on the one end side and the other end side is easily relaxed.

The gap between the first heat radiation fin 82a and the second heat radiation fin 82b may extend in a direction intersecting the axial direction of the spindle shaft body 22.

In this way, compared to the case where the gap between the first heat radiation fin 82a and the second heat radiation fin 82b is parallel to the axial direction of the spindle shaft body 22, it is easier to alleviate the temperature gradient generated between the one end side and the other end side of the spindle shaft body 22 of the spindle mount 26.

The surface area of the second heat dissipation fins 82b may be larger than the surface area of the first heat dissipation fins 82 a.

In this way, the temperature gradient generated between the one end side and the other end side of the spindle shaft body 22 of the spindle mount 26 is more easily relaxed.

The first and second heat radiation fins 82a and 82b may be fixed to the spindle mount 26 at one position.

Thus, warping of the heat sink 82 due to a temperature difference between the spindle mount 26 and the heat sink 82 is easily reduced.