JP2001179512A - Working device for inner diameter of and both end faces of cylindrical work, and chuck for grasping cylindrical work - Google Patents

Abstract

PROBLEM TO BE SOLVED: To work the inner surface of and both end surfaces of a cylindrical work by continuous chucking without displacing the work. SOLUTION: A spindle side end face W1 of a cylinder liner W is pressed to a stopper 40 positioned at a contact position P1 to grasp its outer diameter by a grasping claw 19. A cutter holder 56 enters a central hole B of the cylinder liner W, and an inner diameter W3 is worked by an inner diameter working cutter T3. Continuously, the stopper 40 is retracted to a retracting position P2, a front end surface W2 is worked by an end face working cutter T2 mounted on the cutter holder 56, and then a spindle side end face W1 is worked by an end face working cutter T1 mounted on the cutter holder 56. The cylinder liner W is not displaced after it is once grasped by the chuck to execute the working of the inner diameter and the axial both end faces, which shortens a working time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a processing device for performing one chucking on the inner diameter and both end surfaces in the axial direction of a thin cylindrical work such as a cylinder liner used in an engine of an automobile, and a processing device for the same. It relates to the chuck used.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 8, the inner diameter of a thin cylindrical work such as a cylinder liner and the processing of both end faces thereof are performed by grasping the outer diameter of the work W by a grasping claw 101 of a chuck 100. Also, the end face W2 in the chuck axial direction front side (far side from the spindle) is machined, and then the work W is held, the front and rear of the work W are exchanged, and the end face W1 is located at the position where the end face W2 was. , The end face W1 was processed. Further, Japanese Unexamined Patent Publication No.
No. 174301 discloses that one end of a cylindrical work is machined by one chucking. According to this, the axial position of the work is determined by a stopper.
The inner diameter of the work is grasped by the collet chuck, the stopper is retracted in that state, and the end surface on the main spindle side is processed using the space created by the retracted stopper, and the opposite end surface is also processed. is there.

[0003]

In the above, both ends are machined by changing the workpiece, and the machining time is prolonged. Also, with the technique described above, the inner diameter machining of a cylindrical work as in the present application cannot be performed. Especially when the cylindrical work is a cylinder liner,
Since the piston slides on the inner surface, inner diameter processing is extremely important. An object of the present invention is to perform machining of the inner surface and both end surfaces of a cylindrical work by one chucking without changing the work.

[0004]

In order to solve the above-mentioned problems, in the present application, there is provided an apparatus for processing the inner diameter and both end faces of a cylindrical work, wherein a tool holder of a lathe is provided with an inner diameter processing tool in the same tool holder. It is provided with two end face cutting tools for processing both end faces of the cylindrical work, and a main shaft of the lathe is provided with a chuck having a plurality of grasping claws for grasping the outer diameter of the cylindrical work so as to be movable in a radial direction, The chuck has a stopper for abutting against the spindle-side end face of the cylindrical work and positioning the work in the axial direction, and a chuck between the contact position for abutting the cylindrical work and the retracted position moved to the spindle side. The stopper is provided so that it can be moved in the axial direction, and the stopper is used when the cutting tool holder is inserted into the center hole of the cylindrical work in the state where the stopper is in the contact position and the inner diameter machining of the cylindrical work is performed by the inner diameter machining tool. , For cutting tools for bore machining Characterized in that it has a relief space to avoid interference between the end face machining cutting tool disposed on the spindle side of the position (claim 1).

According to this structure, the outer diameter is grasped in a state where the cylindrical work is positioned in the axial direction with the stopper as the contact position, and the inner diameter of the work is processed by the inner diameter cutting tool.
Pull the stopper to the retracted position to form a machining space between the work and the chuck body, control the position of the tool holder that has entered the center hole of the work, and change the work with the end face cutting tool of the tool holder. And process both end surfaces in order. Since these processes can be performed without changing the work, the processing time can be shortened. In addition, since the same tool holder is provided with a cutting tool for the inner diameter and two cutting tools for the end face, a small amount of the tool holder is required. By moving, it is possible to shift from inner diameter processing to both end face processing, and the processing time can be further reduced.

Specifically, the stopper has a cylindrical wall portion facing the main shaft side end surface of the cylindrical work protruding from the bottom wall portion toward the cylindrical work, and a front end surface of the cylindrical wall portion. And the inner space of the cylindrical wall portion is formed as a clearance space (claim 2). A blow nozzle is provided on the bottom wall of the stopper to blow out a pressurized fluid toward a processing portion of the cylindrical workpiece to remove chips (claim 3). According to this, the chips generated at the processing portion are removed from the cylindrical workpiece processing portion by the pressurized fluid, and smooth processing can be performed.

The grasping claw is fixed to a master jaw provided on the chuck body so as to move in the radial direction, and the master jaw acts to cancel the centrifugal force acting on the master jaw and the grasping claw when the chuck rotates. (See claim 4). According to this, the centrifugal force generated in the gripping jaws and the master jaw due to the rotation of the chuck is canceled by a gripping force reduction prevention mechanism such as a counterbalance mechanism, so that a relatively small thin and easily deformed cylindrical work is not deformed. Even when the outer diameter is grasped by the grasping force, the small grasping force can be stably maintained during the rotation of the chuck, and the cutting can be performed smoothly.

Further, the chuck according to the present invention processes both ends of an inner diameter processing tool and a cylindrical workpiece on the same tool holder.
It is provided with two end face cutting tools, and is used when the cutting tool holder is inserted into the center hole of the cylindrical work to perform inner diameter processing, and then the two end face cutting tools are used to sequentially process both end faces of the cylindrical work. A stopper which is provided on a chuck body and has a plurality of grasping claws for grasping an outer diameter of a cylindrical work, which can be moved in a radial direction, and which comes into contact with an end face of a cylindrical work on a main shaft side to position an axial position of the work. Is provided so as to be movable in the chuck axis direction between a contact position where it comes into contact with the cylindrical work and a retracted position moved to the main spindle side, and the stopper has a contact surface with the main spindle side end surface of the cylindrical work. When the inner wall of the cylindrical wall portion is provided, and the inner space of the cylindrical wall portion is in contact with the stopper and the inner diameter processing of the cylindrical work is performed by the inner diameter processing blade, the mounting position of the inner diameter processing blade is set. End face located closer to the spindle An escape space for avoiding interference with the cutting blade is provided, and a blow nozzle for blowing a pressurized fluid obliquely toward a processing portion of the cylindrical work is provided at the stopper (Claim 5). . Also, grasp claws,
The chuck is fixed to a master jaw provided to move in the radial direction on the chuck body, and the master jaw is connected to a master jaw and a gripping force preventing mechanism that acts to cancel the centrifugal force acting on the gripping claw when the chuck rotates. (Claim 6).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a chuck body 1 includes a front body 2 and a rear body 3 for closing a back surface of the front body 2. The front body 2 and the rear body 3 are integrally connected by a connection screw 4. Hereinafter, the spindle S
The direction approaching P is the rear, and the direction moving away from the main axis SP is the front. An accommodation hole 5 for accommodating a driving member is provided inside the chuck body 1, and a wedge plunger 6 shown as a driving member is accommodated in the accommodation hole 5 so as to be able to advance and retreat in the chuck rotation axis CL direction (front-back direction). Have been.
Between the wedge plunger 6 and the holding plate 7, the flange 9 of the female screw member 8 is held, and the wedge plunger 6
The female screw member 8 is integrated. Female thread member 8
Is screwed to the tip of an outer draw pipe 10 connected to a driving source such as a rotary cylinder (not shown) provided at the rear end of the main shaft SP.

A plurality (three in this case) of radial guide grooves 11 are formed in the front body 2 at predetermined angular intervals in the circumferential direction. Each guide groove 11 has a master jaw 12
Is guided movably in the radial direction.
A wedge portion 14 provided on the inner side in the chuck radial direction of the master jaw 12 is engaged with a wedge groove 15 provided on the wedge plunger 6, and when the wedge plunger 6 moves back and forth, the master jaw 12 opens and closes in the radial direction. It has become.

The master jaw 12 has a substantially L-shaped cross-section by integrally projecting a gripping claw mounting portion 16 forward from the guide base 13, and the mounting portion 16 has a widthwise direction as shown in FIG. Reinforcement rib portions 17 are connected to the guide base 12 on both sides, and the space between the reinforcement rib portions 17 is a space 18 to reduce the weight of the master jaw 12. A grasping claw 19 for grasping the outer diameter of a cylinder liner W exemplified as a cylindrical work is integrally fixed to the inside of the mounting portion 16 in the chuck radial direction with a mounting screw 20. The grasping claw 19 has a spike-shaped arc surface 21 whose grasping surface matches the outer shape of the cylinder liner W.
It has become.

A well-known counter balance mechanism 22 is connected to the master jaw 12 as a mechanism for preventing a decrease in gripping force. In the counter balance mechanism 22, a locking groove 23 is formed on the back surface of the guide base 12 of each master jaw 12. An intermediate portion of a counter lever 24 is pivotally supported on a portion of the front body 2 facing the locking groove 23 via a spherical bearing portion 25 so as to be swingable in the radial direction. The front end 26 of the counter lever 24 is engaged with the locking groove 23. A balance weight 27 is provided between the rear body 3 and the front body 2 so as to be slidable in the radial direction corresponding to each master jaw 12, and a counter lever 24 is provided in an engagement hole 28 of the balance weight 27. The rear end 29 is locked. Then, the centrifugal force in the radial direction outward due to the balance weight 27 generated when the chuck rotates,
The counter lever 24 converts the force into a radially inward force and transmits the force to the master jaw 12 to cancel the radially outward centrifugal force generated by the gripping claw 19 (including the mounting screw 20) and the master jaw 12. It has become.

At the center of the front surface of the front body 2, a stopper guide member 30 is integrally fixed. Stopper guide member 30
Has a large-diameter shaft portion 31 and a small-diameter shaft portion 32 extending rearward from the back thereof. The small diameter shaft portion 32 penetrates the center of the female screw member 8 and projects rearward from the rear body 3.
A guide hole 33 is provided in the large-diameter shaft portion 31 so as to open ahead of the chuck axis. The guide hole 33 communicates with a through hole 34 at the center of the small diameter shaft portion 32. Outer peripheral surface 31a of large diameter shaft portion 31
The center hole 6a of the wedge plunger 6 is slidably guided in the axial direction.

A stopper 40 is fitted in the guide hole 33 so as to be able to advance and retreat in the axial direction of the chuck. Stopper 40
The main shaft side end face W of the cylinder liner W extends from the front surface of the disc-shaped bottom wall portion 41 toward the cylinder liner W (front).
A cylindrical wall portion 42 facing 1 is projected, and its front end surface is a contact surface 42a with the main shaft side end surface W1. Bottom wall 4
A front end of a push-pull shaft 43 is screwed to the back surface of 1. The push / pull shaft 43 is slidably guided in the through-hole 34 in the chuck axis direction, and is engaged with a slide key 44 provided integrally with the push / pull shaft 43 and a key groove 45 formed in the through hole 34. In some cases, it is stopped. A male screw portion 46 is formed at the rear end of the push / pull shaft 43, and is connected to a piston rod of a rotary cylinder (not shown) arranged at the rear end of the main shaft via a draw pipe 47 different from the above.
By the movement of the piston rod, the piston rod reciprocates in the axial direction of the chuck between a contact position (projection position) P1 shown by a solid line in FIG. 1 and a retreat position (retraction position) P2 shown by a two-dot chain line. . The inner space of the cylindrical wall portion 31 is:
When the main shaft side end surface W1 of the cylinder liner W is in contact with the contact surface 42a of the cylindrical wall portion 42 in a state of protruding to the contact position P1, when the entire inner diameter is processed by the inner diameter processing blade tool T3 described later, This is a clearance space 48 into which the edge processing blade T1 arranged closer to the main shaft than the blade T3 enters, so that the stopper 40 does not interfere with the edge processing blade T1.

At the center of the push / pull shaft 43, a fluid passage hole 4 is provided.
9 is formed to penetrate, and the tip of the fluid passage hole 49 communicates with a nozzle 50 formed in the bottom wall portion 41. Nozzle 50
Are provided at two places as shown in FIG.
2 is provided diagonally so as to face the inner peripheral surface. The fluid passage hole 49 is connected to a coolant supply source or a compressed air supply source (not shown) through a center hole 47a of the draw pipe 47, and a coolant liquid supplied from the coolant supply source or the compressed air supply source, or The compressed air is blown to the inner diameter portion as a processing portion of the cylinder liner W or the end face W1 on the spindle side of the cylinder liner W. Such a chuck is integrally fixed to a mounting adapter 52 integrally fixed to the tip of the main spindle SP with a mounting bolt 51 with a mounting bolt 53 penetrating through the chuck body 1.

A turret tool rest 55 of the lathe, which is arranged to face the main spindle SP of the lathe, is provided with a tool holder 56 for machining the inside diameter and both end faces. Blade holder 5
Reference numeral 6 is a size that can enter the hollow hole B of the cylinder liner W. An edge processing tool T1 for processing the spindle-side end face W1 of the cylinder liner W is attached to the tip of the spindle holder at the tip of the spindle side, and on the turret tool post side,
An end face processing tool T2 for processing a front end face W2 opposite to the main spindle side end face W1 is attached, and the main spindle side end face W1 is provided.
An inner diameter processing blade T3 of the cylinder liner W is mounted at a position slightly in the direction of the end surface processing blade T2 from the processing blade T1. When the inner diameter processing tool T3 reaches the main shaft side end of the cylinder liner W (the state of FIG. 1), the front end face W2 and the cutting tool T2 can be processed so that the front end face W2 can be continuously processed after the inner diameter processing. The axial distance between the cutting tool T1 and the cutting tool T2 is set so that a slight axial gap S is generated, and the end face processing by the cutting tool T1 can be performed immediately after the processing with the cutting tool T2. W
Are set slightly longer than the axial length (distance between both end faces) of the cutting tool T1, and the cutting tools T1 and T3 are attached so that the other cutting tool does not interfere with the cylinder liner W when processing with one cutting tool. As is well known, the turret tool rest 55 is controlled to change a spatial position with respect to the cylinder liner W, so that a corresponding processing portion can be processed by each of the blade tools T1 to T3. In the present embodiment, all the cutting blades of the cutting tools T1 to T3 face forward with respect to the paper surface of FIG.

Next, the operation will be described. The grasping claw 19 is at the unchucking position where it has moved radially outward, and
It is assumed that the stopper 40 is at the retreat position P2. Prior to gripping of the cylinder liner W, the stopper 40 is advanced from the retreat position P2 to be at the contact position P1. Next, the spindle liner W is pressed against the contact surface 42 a of the stopper 40 by hand or by a loader such as a robot. While maintaining the contact state, the wedge plunger 6 is moved rearward through the outer draw pipe 10 so that the wedge portion 14 and the wedge groove 1 are moved.
The master jaw 12 is moved radially inward from the unchucking position by engagement with the master jaw 5, and the outer diameter of the wedge plunger 6 is chucked by the gripping claws 19 at the tip of the master jaw 12. When this work is mounted, the blade holder 5
6 is far from the chuck. The gripping force of the gripping claws 19 is set to a level that does not cause as much distortion as possible in the thin and easily distorted cylinder liner W, and is set to a level that can sufficiently oppose the cutting resistance (FIG. 3). .

Next, the lathe is started, and the spindle SP rotates forward. The position of the turret tool rest 55 is controlled, the cutting tool holder 56 enters the hollow hole B of the cylinder liner W, and the inner diameter W3 from one end to the other end of the cylinder liner W is processed by the cutting tool T3. At this time, coolant or pressurized air blows obliquely to the inner surface of the cylindrical wall portion 31 through the pressurized fluid passage hole 49 and the nozzle 50, and chips generated at the time of inner diameter machining are generated by the flow of the pressurized fluid. From the cylinder liner W and discharged outward from the front opening of the cylinder liner W. Since the entire circumference of the contact surface 42a is in pressure contact with the spindle-side end surface W1 of the cylinder liner W, the pressurized fluid blown out from the nozzle 50 causes the cylindrical wall portion 31 and the spindle-side end surface W1. There is little leakage from between, and it can be used without waste for chip discharge.

When the inner diameter is processed by the cutting tool T3 and is processed to a position near the end of the cylinder liner W, the cutting tool T1 protrudes toward the main shaft from the main shaft side end face W1 of the cylinder liner W. It does not enter the inner clearance space 48 and interfere with the stopper 40 (FIG. 4). When the cutting tool T3 processes the inner diameter W3 up to the main shaft side of the cylinder liner W (the state of FIG. 1), the stopper 40 is moved backward to the retracted position P2. At the retreat position P2,
A sufficient space is formed between the contact surface 42a of the stopper 40 and the spindle-side end surface W1 of the cylinder liner W to allow the blade T1 to protrude and process the spindle-side end surface W1. Next, the cutting tool holder 56 is moved so that the cutting tool T2 is at a processing position where the front end face W2 is processed, and the front end face W2 is subsequently processed. At the time when the inner diameter machining is completed, the cutting tool T2 has reached a position separated from the front end face W2 by a small distance S in the axial direction, so that the amount of movement of the cutting tool holder 56 when moving to machining with the cutting tool T2 is extremely large. There is little waste time for shifting from the inner diameter processing step to the processing step of the front end face W2 (FIG. 5).

When the processing of the front end face W2 is completed, the tool holder 56 is then moved so that the tool T1 is at a position where the tool T1 cuts the spindle end face W1, and the spindle end face W1 is cut.
Since the axial distance between the cutting tools T1 and T2 is slightly larger than the axial length of the cylinder liner W, the time required to move the cutting tool T1 to the processing position on the main spindle side end face W1 after processing the front end face W2 is also increased. , Very slight. Also, during the processing of the spindle-side end face W1, the pressurized fluid blows out from the nozzle 50 toward the spindle-side end face W1, so that the chips being processed are reliably removed (FIG. 6). These cutting tools T1,
At the time of the end face machining at T2, in the present embodiment, the spindle SP is rotated in the reverse direction due to the direction of the cutting edge. When the machining of the spindle-side end face W1 is completed in this way, the blade holder 56 comes out of the hollow hole B of the cylinder liner W in the axial direction. Thereafter, the rotation of the spindle SP is stopped, the wedge plunger 6 is moved forward, the cylinder liner W is unchucked and taken out, and the stopper 40 is projected to the contact position for the next work set (FIG. 7).

During machining, the chuck is rotated by the rotation of the main shaft SP, and a radially outward centrifugal force acts on the master jaw 12 and the gripping claws 19 to reduce the gripping force. Since the radially outward centrifugal force acts on the master jaw 12 via the counter lever 24 as a force directed inward in the radial direction of the master jaw 12, the radially outward centrifugal force generated on the master jaw 12 and the gripping claws 19 is generated. The centrifugal force is cancelled, and the gripping force of the gripping claws 19 is prevented from decreasing, and the gripping force holding the cylinder liner W so as not to be distorted is stably maintained. In the present embodiment, the front end face W2 is machined following the inner diameter machining, and then the main spindle side end face W1 is machined.
The processing order of W2 may be reversed. Further, the rotation of the spindle SP was switched between forward and reverse during the processing by the cutting tool T3 and the cutting tools T1 and T2.
, So that the cutting tool T
If 3 is attached, the rotation of the main shaft SP is all unified in the same direction.

[0022]

As described above, according to the present invention, the inner surface and both end surfaces can be machined without changing the cylindrical work, and the machining time can be shortened. In addition, since the same tool holder is provided with a cutting tool for the inner diameter and two cutting tools for the end face, a slight movement of the cutting tool holder inserted into the hollow hole of the cylindrical work allows two end face processings from the inner working. And the processing time can be further reduced. In addition, since the pressurized fluid is blown out from the stopper toward the processing part of the cylindrical work, chips generated at the processing part can be immediately removed,
Cutting can be performed smoothly. In addition, a built-in gripping force reduction mechanism such as a counterbalance mechanism is built into the chuck to counteract the centrifugal force generated in the gripping claw and master jaw, thereby preventing a reduction in gripping force. Even when the outer diameter of a thin cylindrical workpiece that is easily distorted is grasped with a small grasping force so as to suppress deformation as much as possible, the small grasping force can be stably maintained while the chuck is rotating, and cutting can be performed. It can be done smoothly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state at the time of finishing an inner diameter machining in an apparatus of the present invention.

FIG. 2 is a front view of a chuck used in FIG.

FIG. 3 is an operation explanatory diagram showing a time of chucking.

FIG. 4 is an operation explanatory diagram showing an inside diameter cutting operation.

FIG. 5 is an operation explanatory view showing cutting of the front end surface.

FIG. 6 is an operation explanatory view showing cutting of the spindle-side end surface.

FIG. 7 is an explanatory diagram of an operation at the time of work unchucking.

FIG. 8 shows a conventional processing method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chuck body 12 Master jaw 19 Grasp claw 22 Counter balance mechanism (grasping force lowering prevention mechanism) 40 Stopper 42 Cylindrical wall portion 42a Contact surface 48 Escape space 50 Blowout nozzle 55 Turret tool rest 56 Tool holder B Center hole P1 Contact Position P2 Evacuation position T1, T2 End face cutting tool T3 Inner diameter cutting tool W Cylinder liner (tubular work) W1 Main shaft side end face W2 Front end face W3 Inner diameter

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B23B 5/26 B23B 5/26

Claims (6)

[Claims] An apparatus for processing the inner diameter and both end faces of a cylindrical work, wherein a tool post of a lathe has two end face processing tools for processing both end faces of an inner diameter processing blade and a cylindrical work in the same blade holder. Equipped with a chuck comprising a plurality of grasping claws for grasping the outer diameter of the cylindrical work so as to be movable in the radial direction, and the chuck has a spindle-side end face of the cylindrical work. A stopper for contacting and positioning the work in the axial direction is provided so as to be movable in the chuck axial direction between a contact position for contacting the cylindrical work and a retracted position moved to the spindle side, and the stopper is a stopper. When the cutting tool holder is inserted into the center hole of the cylindrical work in the state where it is in the abutment position, and the inside diameter machining of the cylindrical work is performed by the cutting tool for inside diameter processing, it is arranged closer to the spindle than the mounting position of the cutting tool for inside diameter processing. End face cutting tool provided An apparatus for processing the inner diameter and both end faces of a cylindrical work, characterized by having a clearance space for avoiding interference with the cylindrical work. 2. The stopper has a cylindrical wall portion protruding from the bottom wall portion toward the cylindrical work in a direction facing the main shaft side of the cylindrical work, and abutting the front end surface of the cylindrical wall portion. 2. The apparatus for processing the inner diameter and both end faces of a cylindrical work according to claim 1, wherein the inner surface of the cylindrical wall portion is formed as a clearance space in addition to the surface. 3. The cylindrical work according to claim 2, wherein a blow nozzle for blowing out a pressurized fluid toward a processing portion of the cylindrical work to remove chips is provided on a bottom wall portion of the stopper. For processing the inner diameter and both end faces of 4. The grasping claw is fixed to a master jaw provided on the chuck body so as to move in the radial direction, and acts on the master jaw to cancel a centrifugal force acting on the master jaw and the grasping claw when the chuck rotates. The apparatus for processing the inner diameter and both end faces of a cylindrical work according to any one of claims 1 to 3, wherein a mechanism for preventing a decrease in gripping force is connected. 5. The same blade holder is provided with an inner diameter processing blade and two end surface processing blades for processing both end surfaces of a cylindrical work, and the inner surface is processed by inserting the blade holder into a central hole of the cylindrical work. Then, a chuck used for sequentially processing both end faces of the cylindrical work with two end face processing blades, and a plurality of grasping claws for grasping the outer diameter of the tubular work are provided on the chuck body in a radial direction. A stopper that is movably provided and abuts against the spindle-side end face of the cylindrical workpiece to position the workpiece in the axial direction. The stopper is provided between the contact position that contacts the cylindrical workpiece and the retracted position that is moved toward the spindle. The stopper is provided so as to be movable in the axial direction, and the stopper has a cylindrical wall portion having a contact surface with the end face on the main shaft side of the cylindrical work, and the inner space of the cylindrical wall portion is located at the contact position where the stopper is in contact. Internal diameter machining of cylindrical workpieces with internal machining tools When performing the machining, a clearance space for avoiding interference with the end face machining blade disposed on the spindle side from the mounting position of the inner diameter machining tool is provided. A chuck for gripping a cylindrical workpiece, comprising a blow nozzle for blowing a pressurized fluid obliquely toward the chuck. 6. The grasping claw is fixed to a master jaw provided on the chuck body so as to move in the radial direction, and acts on the master jaw to cancel the centrifugal force acting on the master jaw and the grasping claw when the chuck rotates. 6. A chuck for gripping a cylindrical workpiece according to claim 5, further comprising a mechanism for preventing a decrease in gripping force.