阅读说明：本技术 卡盘的防尘机构和卡盘 (Dustproof mechanism of chuck and chuck ) 是由 永翁博 于 2020-03-25 设计创作，主要内容包括：技术方案：卡盘的防尘机构包括流体供给源、设置于卡盘内部的内部空间、以及设置于卡盘的排出空间。供给流体从流体供给源供给到内部空间并成为加压流体而经过内部空间。排出空间从内部空间向卡盘的外部排出加压流体。(The technical scheme is as follows: the dustproof mechanism of the chuck comprises a fluid supply source, an inner space arranged in the chuck and a discharge space arranged in the chuck. The supply fluid is supplied from the fluid supply source to the interior space and passes through the interior space as a pressurized fluid. The discharge space discharges the pressurized fluid from the internal space to the outside of the chuck.)

1. A dust prevention mechanism of a chuck for preventing intrusion of foreign matter into an interior of the chuck, comprising:

a fluid supply source;

an internal space provided inside the chuck and through which a supply fluid supplied from the fluid supply source passes as a pressurized fluid; and

a discharge gap provided to the chuck and discharging the pressurized fluid from the inner space to an outside of the chuck.

2. The dust-proof mechanism of a chuck according to claim 1,

the chuck may further include a through flow path that communicates the fluid supply source with the internal space and penetrates a driving member that drives the jaw seat of the chuck.

3. The dust-proof mechanism of a chuck according to claim 2,

the through flow path extends along a central axis of the chuck.

4. The dust-proof mechanism of a chuck according to any one of claims 1 to 3,

further comprising a first sealing member disposed in a gap other than the discharge gap of the chuck.

5. The dust-proof mechanism of a chuck according to any one of claims 1 to 4,

the discharge gap is a gap between a guide groove extending in a radial direction of a chuck body of the chuck and a jaw seat inserted into the guide groove.

6. The dust-proof mechanism of a chuck according to claim 5,

the discharge gap is a gap that is open on a surface on the side where the pawl is attached, of gaps between the guide groove and the pawl holder.

7. The dust-proof mechanism of a chuck according to claim 6,

the seal device further includes a second seal member that covers a gap between the pawl seat and the guide groove from a radially outer side.

8. The dust-proof mechanism of a chuck according to any one of claims 1 to 7,

the fluid supply device further comprises a supply amount adjusting part for adjusting the supply amount of the supply fluid.

9. The dust-proof mechanism of a chuck according to any one of claims 1 to 8,

the lubricant supplying device further includes a mixing section that mixes the lubricant into the supply fluid.

10. The dust-proof mechanism of a chuck according to claim 9,

the mixing section includes a mixing amount adjusting section that adjusts a mixing amount of the lubricant mixed into the supply fluid.

11. A chuck is characterized in that a chuck body is provided with a chuck body,

the chuck includes the dust-proof mechanism of the chuck according to any one of claims 1 to 10.

Technical Field

The present invention relates to a dust-proof mechanism for a chuck and a chuck for preventing foreign matter from entering the chuck.

Background

Conventionally, an operating mechanism for moving the chuck jaws is provided inside the chuck. A dust-proof mechanism is known in which chip powder, cutting oil, or the like enters the chuck and does not adversely affect the chuck operation.

For example, a dust-proof mechanism as in patent document 1 is known. Here, a cover plate and a dust-proof plate are mounted on the front surface of the chuck body. The dust-proof plate is biased radially outward by a spring member and closes a gap between a bottom jaw connected to the claw seat and a notch of the cover plate. Further, for example, a dust-proof mechanism as in patent document 2 is known. Here, a center cap is attached to a front surface of the chuck body, and a high-pressure refrigerant liquid supplied from a machine tool is discharged from a back side of a peripheral edge portion of the center cap toward an outer side in a radial direction. Thus, the discharged refrigerant blows off dust such as chip powder attached to the periphery of the chuck.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. H04-136603

Patent document 2: international publication No. 2018/092879

Disclosure of Invention

Technical problem to be solved by the invention

However, in patent document 1, when a failure occurs in the spring member, it is difficult to close the gap between the bottom jaw and the notch of the cover plate by the dust-proof plate. In this case, foreign matter such as chip powder and cutting oil may enter the chuck body through the gap. In patent document 2, there is a possibility that dust such as chip powder is pressed into the gap between the chuck body and the chuck jaws by the high-pressure refrigerant liquid.

In view of the above problems, an object of the present invention is to provide a dust-proof mechanism for a chuck and a chuck, which can prevent foreign matter from entering the chuck.

Technical scheme for solving technical problem

The invention provides a dustproof mechanism of a chuck, which is used for preventing foreign matters from entering the interior of the chuck, and comprises:

a fluid supply source;

an internal space provided inside the chuck and through which a supply fluid supplied from the fluid supply source passes as a pressurized fluid; and

and a discharge gap provided in the chuck and discharging the pressurized fluid from the internal space to the outside of the chuck.

In the above-described dust-proof mechanism of the chuck,

the chuck may further include a through flow path that communicates the fluid supply source with the internal space and that passes through a driving member that drives the jaw seat of the chuck.

In the above-described dust-proof mechanism of the chuck,

the through flow passage may extend along a center axis of the chuck.

In the above-described dust-proof mechanism of the chuck,

the chuck may further include a first sealing member provided in a gap other than the discharge gap of the chuck.

In the above-described dust-proof mechanism of the chuck,

the discharge gap may be a gap between a guide groove extending in a radial direction of a chuck body provided in the chuck and a jaw seat inserted into the guide groove.

In the above-described dust-proof mechanism of the chuck,

the discharge gap may be a gap that is open on a surface of the chuck on the side where the claws are attached, of gaps between the guide groove and the claw holder.

In the above-described dust-proof mechanism of the chuck,

the seal device may further include a second seal member that covers a gap between the claw seat and the guide groove from a radially outer side.

In the above-described dust-proof mechanism of the chuck,

the fluid supply apparatus may further include a supply amount adjusting unit for adjusting a supply amount of the supply fluid.

In the above-described dust-proof mechanism of the chuck,

the lubricant supplying device may further include a mixing portion that mixes the lubricant into the supply fluid.

In the above-described dust-proof mechanism of the chuck,

the mixing section may further include a mixing amount adjusting section that adjusts a mixing amount of the lubricant mixed into the supply fluid.

In addition, the present invention provides a chuck,

the chuck comprises the dustproof mechanism of the chuck.

Effects of the invention

According to the present invention, foreign matter can be prevented from entering the chuck.

Drawings

Fig. 1 is a diagram showing a chuck including a dust-proof mechanism according to an embodiment of the present invention.

Fig. 2 is a view showing a state where the claws are taken out from the chuck of fig. 1.

Fig. 3 is a view III of fig. 2 and is a view showing a cross section of the chuck in a state where the driving member is advanced.

Fig. 4 is an enlarged view of a part of the view IV of fig. 2.

Fig. 5 is a perspective view illustrating the second sealing member of fig. 3 in a state where the jaw seat and the jaw guide member are omitted.

Fig. 6 is a view showing a section taken along line VI-VI in fig. 4.

Fig. 7 is a diagram showing a state where the driving member is retracted.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, an example will be described in which the chuck is a chuck fixed to a spindle of a machine tool such as an NC lathe.

As shown in fig. 1 to 3, the chuck 1 is fixed to a spindle 50 (fig. 3) of a machine tool such as an NC lathe. The chuck 1 includes: a chuck body 2; a jaw seat 7, the jaw seat 7 being provided in the chuck body 2; and a driving member 8, wherein the driving member 8 is disposed inside the chuck body 2.

The chuck body 2 has a mounting groove 3 extending in a radial direction, and the workpiece W is clamped by a claw 4 attached to the mounting groove 3. The workpiece W is conveyed to the chuck 1 by a loader 51 exemplified as a conveying device. The workpiece W held by the chuck 1 is machined by moving a tool post (not shown) including a plurality of tools in the front, rear, left, and right directions. When the diameter of the workpiece W to be machined changes or wear occurs due to long-term use, the claw 4 is replaced manually or by a claw automatic replacement device (not shown).

The chuck body 2 includes a front body 5 and a rear body 6 provided on a rear end surface of the front body 5 by mounting bolts (not shown). A plurality of mounting grooves 3 (e.g., 3) are provided on the front surface of the front body 5. The mounting grooves 3 are arranged at equal intervals in the circumferential direction. In addition, the precursor 5 includes: a cylindrical first inner peripheral surface 5 a; and a cylindrical second inner peripheral surface 5 b. The first inner peripheral surface 5a is provided on the rear side, and the second inner peripheral surface 5b is provided on the front side. The diameter of the second inner peripheral surface 5b is smaller than the diameter of the first inner peripheral surface 5 a. The front side refers to a side to which the claw 4 can be attached, and the rear side refers to a side of the spindle 50 of the machine tool.

The pawl seat 7 is disposed in each guide groove 25 of the front body 5. The guide groove 25 is disposed to correspond to the mounting groove 3 and extends in the radial direction. As shown in fig. 3 and 4, each guide groove 25 forms a space continuous with the corresponding mounting groove 3. The pawl base 7 is movable in the radial direction in the guide groove 25.

As shown in fig. 3, the coupling member 12 is provided to be able to advance and retreat in the pawl base 7. The coupling member 12 includes a rack-shaped coupling portion 12a that can be coupled to a coupling surface 4a (described later) of the pawl 4. The coupling member 12 is movable between a coupling position coupled to the claw 4 and a release position separated from the claw 4. When the coupling member 12 is located at the coupling position, the claws 4 guided to the mounting groove 3 are coupled to the claw seats 7. The coupling portion 12a engages with the coupling surface 4 a.

The claw 4 includes: a bottom jaw 13; and a top jaw 15, wherein the top jaw 15 is fixed to the front surface of the bottom jaw 13 by a plurality of bolts 14. The bottom jaw 13 is inserted into the mounting groove 3. The mounting groove 3 is formed in front of the jaw seat 7 inserted into the guide groove 25. A coupling surface 4a is provided on the rear surface of the bottom jaw 13.

As shown in fig. 1 to 4, a mounting surface 11 is formed at a position corresponding to each mounting groove 3 (a position on the outer peripheral side of the mounting groove 3) in the outer peripheral surface of the front body 5 of the chuck body 2. As shown in fig. 4 and 5, the mounting surface 11 is formed flat in a range from the mounting groove 3 to the guide groove 25. As shown in fig. 4, the claw guide member 10 is attached to the attachment surface 11 by a bolt 26. The claw guide member 10 is configured to guide the newly attached claw 4 to the attachment groove 3 of the chuck body 2 when the replacement is performed by a manual or automatic claw replacement device (not shown).

As shown in fig. 3, the driving member 8 drives the pawl holder 7. The drive member 8 has a set screw 27, a wedge shaped plunger 28 and a retainer 29. The draw screw 27, the wedge plunger 28, and the retainer 29 are integrally movable along the center axis CL.

The draw screw 27 is disposed centering on the center axis CL of the chuck body 2.

A wedge-shaped plunger 28 is mounted to the front surface of the draw screw 27. The wedge-shaped plunger 28 has a wedge-shaped engagement groove 28a, and the wedge portion 7a of the pawl holder 7 engages with the wedge-shaped engagement groove 28 a. Thereby, the draw screw 27 is engaged with each of the pawl seats 7 via the wedge-shaped plunger 28. The wedge-shaped engagement groove 28a is inclined with respect to the center axis CL.

The retainer 29 is interposed between the set screw 27 and the front body 5. The retainer 29 is disposed between the first inner peripheral surface 5a of the front body 5 and the outer peripheral surface of the draw screw 27. The retainer 29 is attached to the set screw 27 and is slidable on the first inner peripheral surface 5a of the front body 5. The draw screw 27 is held by a wedge plunger 28 to a drive guide member 9 described later, and is held by a retainer 29 to the front body 5.

The driving member 8 is configured to move each of the pawl seats 7 in the radial direction along the guide groove 25 by moving forward (rightward in fig. 3) or backward (leftward in fig. 3, see fig. 7) along the center axis CL. That is, as shown in fig. 3, when the driving member 8 advances, each of the pawl seats 7 moves outward in the radial direction. On the other hand, as shown in fig. 7, when the driving member 8 retreats, each of the pawl seats 7 moves inward in the radial direction. Thus, when the claws 4 are coupled to the coupling members 12 of the claw holder 7, the claws 4 can be moved radially outward by the forward movement of the driving member 8, and the claws 4 can be moved radially inward by the backward movement of the driving member 8.

As shown in fig. 3, a drive guide member 9 (also referred to as a guide bush) is provided inside the front body 5. The drive guide member 9 is configured to guide the movement of the drive member 8. More specifically, the driving guide member 9 includes: a cylindrical portion 9 a; and a rear end portion 9b provided at a rear end portion of the cylindrical portion 9 a. The cylindrical portion 9a is formed concentrically with the center axis CL. The distal end of the cylindrical portion 9a is attached to the second inner peripheral surface 5b of the front body 5. The outer peripheral surface of the cylindrical portion 9a is a guide surface for guiding the movement of the wedge-shaped plunger 28 attached to the driving member 8. The rear end portion 9b is formed perpendicularly to the center axis CL and is opposed to the front surface of the driving member 8. An external space B is formed inside the cylindrical portion 9 a. The external space B opens at the front surface of the chuck body 2. The external space B can be inserted with a part of the workpiece W in a state where the claw 4 grips the workpiece W.

As shown in fig. 1 to 3, a first cover member 30 is attached to a front surface of each of the pawl seats 7. The first cover member 30 extends radially inward from the corresponding pawl seat 7 beyond the cylindrical portion 9a of the drive guide member 9. In addition, a second cover member 31 is mounted between the first cover members 30 adjacent to each other in the circumferential direction. The first cover member 30 and the second cover member 31 cover a gap between the end portion on the inner side in the radial direction of the pawl seat 7 and the front body 5 and a gap between the front body 5 and the cylindrical portion 9a of the drive guide member 9. Therefore, foreign matter such as chip powder and cutting oil is prevented from entering the gap. The external space B is open radially inward of the first cover member 30 and the second cover member 31.

The chuck 1 according to the present embodiment includes a dust-proof mechanism 16, and the dust-proof mechanism 16 prevents foreign matter such as cutting powder and cutting oil generated during machining of the workpiece W from entering the chuck 1. The dust-proof mechanism 16 is configured to supply a supply fluid to an internal space a formed by the precursor 5 and the driving member 8 via the driving member 8 for operating the chuck 1, and to pressurize the internal space a. The dust-proof mechanism 16 is configured to supply the pressurized fluid in the internal space a to a discharge gap 32, which will be described later, of the chuck body 2, and to discharge the pressurized fluid from the discharge gap 32 to the outside of the chuck body 2.

More specifically, the dust-proof mechanism 16 according to the present embodiment includes: an air supply source 18 exemplified as a fluid supply source; an internal space a provided inside the chuck 1; and a discharge gap 32 provided in the chuck 1.

The air supply source 18 supplies supply air as an example of supply fluid to the discharge gap 32. The air supply source 18 may be configured to supply air as supply air into the internal space a. The supply fluid is not limited to air, and may be a gas other than air, which is excellent in operability, or may be a liquid.

The internal space a is connected to the air supply source 18, and pressurizes the supply air supplied from the air supply source 18. The inner space a includes a space defined by the front body 5, the pawl seat 7, the driving member 8, and the driving guide member 9. The internal space a is used as a term indicating a space formed between the components adjacent to each other inside the chuck 1. In the present embodiment, the internal space a has the following structure: the plurality of spaces including the minute gaps communicate in such a manner as to form a flow path through which air passes. As for the volume of the space defined between the front surface of the driving member 8 and the rear end portion 9b of the driving guide member 9 in the internal space a, the volume is larger in the case where the driving member 8 is retreated as shown in fig. 7 than in the case where the driving member 8 is advanced as shown in fig. 3.

The air supply source 18 and the internal space a communicate with each other through the through flow path 27 a. The through flow path 27a passes through the set screw 27 of the drive member 8. The through flow passage 27a may extend along the center axis CL. The through flow path 27a is open at the front surface of the puller screw 27 and communicates with the internal space a.

One end of the supply pipe 17 is connected to the through flow path 27 a. An air supply source 18 is connected to the other end of the supply pipe 17. The supply air from the air supply source 18 is supplied to the internal space a of the chuck body 2 via the supply pipe 17 and the through flow path 27 a.

The discharge gap 32 is a gap for discharging the pressurized air from the internal space a to the outside of the chuck body. The discharge gap 32 may be a gap provided between the guide groove 25 extending in the radial direction of the front body 5 and the pawl seat 7 inserted into the guide groove 25. More specifically, as shown in fig. 2 to 4, the discharge gap 32 may be a gap that is open on the front surface (the surface on the side where the claws 4 are attached) of the chuck body 2, of the gaps between the guide groove 25 and the side surfaces 7b (see fig. 4 and 6) of the claw holder 7. The discharge gap 32 communicates with the mounting groove 3 to which the claw 4 is mounted. Therefore, in the case where the claws 4 are attached to the attachment groove 3, the pressurized air is discharged from the discharge gap 32 to the outside of the chuck body 2 via the gap between the claws 4 and the attachment groove 3.

As shown in fig. 3, the dust-proof mechanism 16 may include first seal members 19a to 19d provided in gaps other than the discharge gap 32 among the gaps provided in the chuck body 2 in order to discharge the pressurized air to the outside from the discharge gap 32. The first sealing members 19a to 19d may be provided in a plurality of gaps of the chuck 1. For example, the first sealing member 19a may be provided in a gap between the front body 5 and the first cover member 30. The first seal member 19b may be provided in a gap between the front body 5 and the cylindrical portion 9a of the drive guide member 9. The first seal member 19c may be provided in a gap between the puller screw 27 and the retainer 29, and the first seal member 19d may be provided in a gap between the retainer 29 and the front body 5. Each of the first seal members 19a to 19d may be an O-ring formed of an elastic material such as rubber, for example.

In order to discharge the pressurized air from the discharge gap 32 to the outside, as shown in fig. 3 to 6, the dust-proof mechanism 16 may include a second seal member 20, and the second seal member 20 may cover the gap between the claw seat 7 and the guide groove 25 from the radially outer side. The pawl seat 7 protrudes above the second seal member 20. As shown in fig. 6, the second sealing member 20 abuts against the mounting surface 11 formed on the outer peripheral surface of the front body 5, and also abuts against the side surface 7b and the rear surface 7c of the pawl seat 7. Thereby, the gap between the pawl seat 7 and the guide groove 25 is covered and sealed from the outside in the radial direction. As shown in fig. 4 and 5, the second seal member 20 is formed so as to partially surround the circumference of the pawl seat 7 when viewed from the outside in the radial direction. More specifically, the second seal member 20 abuts both side surfaces 7b and the rear surface 7c of the pawl seat 7, and is formed in a rectangular frame shape with a portion cut away. Thus, the second seal member 20 covers the gaps between the guide groove 25 and the side surfaces 7b and the rear surface 7c of the pawl seat 7 from the radially outer side.

As shown in fig. 4 and 5, the second seal member 20 may be fixed to the mounting surface 11 by a plurality of bolt members 21. The second seal member 20 may be formed of an elastic material such as rubber. Alternatively, the second sealing member 20 may be formed of a resin material harder than an elastic material such as rubber. In this case, a layer of an elastic material such as rubber may be formed on the contact surface of the second seal member 20 with the pawl seat 7 and the contact surface with the attachment surface 11.

As shown in fig. 3, the dust-proof mechanism 16 may include a flow rate adjustment valve 22 as an example of a supply amount adjustment unit. The flow rate adjustment valve 22 may be attached to the supply pipe 17, and may adjust the supply amount of the supply air supplied from the air supply source 18 to the internal space a. The discharge amount of the pressurized air discharged from the gap of the chuck body 2 is adjusted by the flow rate adjusting valve 22. When the claws 4 are replaced by the automatic claw replacement device, the flow rate adjustment valve 22 may be controlled by a control device (not shown). Alternatively, in the case where the claw 4 is replaced manually, the flow rate adjustment valve 22 may be manually operated.

The dust-proof mechanism 16 may further include a mixing portion 33, and the mixing portion 33 mixes the lubricant into the supply air. When the pressurized air is continuously discharged from the internal space a to the outside, the lubricant applied to the components constituting the chuck 1 in advance is removed, and the operation of the chuck 1 may be affected. Therefore, the dust-proof mechanism 16 may be configured to be able to mix the lubricant into the supply air supplied from the air supply source 18. More specifically, the mixing section 33 may include a lubricant supply pump 34 that supplies lubricant (e.g., lubricating oil) to the supply pipe 17, and a mixing pipe 35 that connects the lubricant supply pump 34 and the supply pipe 17. In this way, the lubricant stored in the lubricant storage unit, not shown, is supplied to the supply pipe 17 by the lubricant supply pump 34 and mixed into the supply air in a mist form. The supply air mixed with the lubricant is supplied to the internal space a and pressurized.

The distribution valve 36 exemplified as the mixing amount adjusting unit may be attached to the mixing pipe 35. The mixing amount of the lubricant mixed into the supply air supplied to the internal space a of the chuck 1 is adjusted by the distribution valve 36. When the claw 4 is replaced by the automatic claw replacement device, the distribution valve 36 may be controlled by a control device (not shown). Alternatively, in the case of replacing the claw 4 by hand, the dispensing valve 36 may also be operated manually.

As described above, according to the present embodiment, the supply air supplied from the air supply source 18 to the internal space a is pressurized, and the pressurized air in the internal space a is discharged from the internal space a to the outside of the chuck 1 through the discharge gap 32. This can prevent foreign matter such as chip powder and lubricant from entering the chuck 1 from the outside through the discharge gap 32. In this case, it is possible to prevent the movement of the movable components such as the claw seat 7 and the driving member 8 in the chuck 1 from being hindered by the entering foreign matter. In addition, since the pressurized air is discharged from the internal space a to the outside through the discharge gap 32, the configuration of the air supply flow path can be simplified. Therefore, the intrusion of foreign matter can be prevented with a simple structure.

Further, according to the present embodiment, the through-flow passage 27a for communicating the air supply source 18 with the internal space a is inserted through the set-up screw 27 of the driving member 8 for driving the pawl holder 7. This can simplify the structure of the air supply flow path. In particular, according to the present embodiment, the through flow path 27a extends along the center axis CL. This makes it possible to uniformly supply the pressurized air to the discharge gap 32 defined by the respective claw seats 7 arranged at different positions in the circumferential direction. In addition, the lowering of the rotation balance of the chuck 1 can be prevented, and the vibration generated by the rotation can be reduced.

In addition, according to the present embodiment, the first seal members 19a to 19d are provided in the gaps other than the discharge gap 32 of the chuck 1. This allows the gaps other than the discharge gap 32 to be sealed by the first seal members 19a to 19d, and prevents the pressurized air from being discharged to the outside through the gaps. Therefore, the pressurized air can be supplied intensively to the discharge gap 32, and the discharge amount (or discharge speed) of the pressurized air from the discharge gap 32 can be increased. As a result, it is possible to further prevent foreign matter from entering from the outside of the chuck 1 to the inside through the discharge gap 32.

In addition, according to the present embodiment, the discharge gap 32 is a gap provided between the guide groove 25 extending in the radial direction of the chuck body 2 and the pawl seat 7 inserted into the guide groove 25. The workpiece W is machined by the jaws 4 being attached to the front surface of the chuck 1. Thus, by discharging the pressurized air from the gap existing on the side close to the workpiece W, it is possible to effectively prevent foreign matter such as chip powder and lubricant from entering the gap.

In addition, according to the present embodiment, the discharge gap 32 is a gap that is opened at the front surface of the chuck 1, among the gaps between the guide groove 25 and the pawl seat 7. Thus, by discharging the pressurized air from the discharge gap 32 opened in the front surface of the chuck 1, it is possible to further prevent foreign matter such as chip powder and lubricant from entering the discharge gap 32.

Further, according to the present embodiment, the second seal member 20 covers the gap between the pawl seat 7 and the guide groove 25 from the radially outer side. Thereby, a portion of the gap between the pawl seat 7 and the guide groove 25, which portion is open on the outer peripheral surface of the chuck body 2, can be sealed by the second sealing member 20, and the pressurized air can be prevented from being discharged to the outside from this portion. Therefore, pressurized air can be intensively supplied to the discharge gap 32, which is open on the front surface of the chuck 1, among the gaps between the guide groove 25 and the claw seat 7, and the discharge amount of the pressurized air from the discharge gap 32 can be increased. As a result, it is possible to further prevent foreign matter from entering from the outside of the chuck 1 to the inside through the discharge gap 32.

In addition, according to the present embodiment, the supply amount of the supply air supplied from the air supply source 18 to the internal space a is adjusted by the flow rate adjustment valve 22. Thus, the discharge amount of the pressurized air from the discharge gap 32 can be changed at the time of replacement of the claws 4 of the chuck 1, processing of the workpiece W, or standby of the chuck 1. Therefore, the pressurized air can be efficiently discharged. For example, when the possibility of intrusion of foreign matter is high, the discharge amount of the pressurized air can be increased, and intrusion of foreign matter can be effectively prevented. For example, by increasing the discharge amount of the pressurized air at the time of replacement of the claw 4, foreign matter such as chip powder and lubricant adhering to the newly attached claw 4 can be blown off by the pressurized air. Therefore, the foreign matter can be further prevented from entering the discharge gap 32. The discharge amount of the pressurized air may be increased at the time of replacement of the claw 4 as compared with the time of machining the workpiece W, and in this case, the intrusion of foreign matter can be further prevented. Since foreign matter such as chip powder and lubricant is generated in front of the chuck 1 during machining of the workpiece W, the entry of foreign matter into the discharge gap 32 can be further prevented by increasing the discharge amount of the pressurized air. On the other hand, since the possibility of intrusion of foreign matter is low during standby of the chuck 1, the discharge amount of pressurized air can be reduced, and the amount of air used can be reduced.

In addition, according to the present embodiment, the lubricant is mixed into the supply air. This makes it possible to supply the supply air mixed with the lubricant into the internal space a. Therefore, the lubricant can be attached to the member from which the lubricant is removed by the pressurized air. Therefore, the movable members such as the claw seat 7 and the driving member 8 in the chuck 1 can be smoothly moved.

Further, according to the present embodiment, the mixing amount of the lubricant mixed into the supply air is adjusted by the distribution valve 36. This enables efficient adhesion of the lubricant. For example, when the discharge amount of the pressurized air is increased at the time of replacement of the claw 4 or at the time of machining the workpiece W, it is considered that the lubricant is highly likely to be removed by the pressurized air. In this case, the lubricant can be efficiently adhered to each member by increasing the mixing amount of the lubricant. On the other hand, when the discharge amount of the pressurized air is reduced during standby of the chuck 1, it is considered that the lubricant is less likely to be removed by the pressurized air. In this case, the amount of lubricant used can be reduced by reducing the amount of lubricant mixed.

The present invention is not limited to the above-described embodiments, and can be implemented by appropriately changing a part of the configuration without departing from the scope of the invention.