JP2000308909A - Work holding device - Google Patents

Abstract

(57) [Problem] To provide a work gripping device that can be mounted on a spindle of an existing machine tool and used to improve versatility. SOLUTION: When moving a claw member 19 for gripping a work, an outer cylinder detent pin 29a is moved to the cylindrical member 1.
6, the rotation of the outer cylinder 14 is restricted, and the cone brake plate 31 is separated from the cylindrical member 16 to separate the outer cylinder 14 from the main body 12. When the main shaft 3 is rotated in this state, the outer cylinder 14 does not rotate, and the scroll member 20 rotates together with the main body 12. Scroll member 20
The rack teeth 23 of the claw member 19 mesh with the scroll teeth 22. The claw member 19 is held by the outer cylinder 14 so as to be movable only in the radial direction. Move in the radial direction. Since the rotational force of the main shaft 3 is used in this way, versatility can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding device used in a machine tool such as a lathe.

[0002]

2. Description of the Related Art A work gripping device (also referred to as a chuck) for gripping a work is mounted on the tip of a spindle of a lathe. The work gripping device is provided with a plurality of claw members arranged at equal intervals around the rotation axis of the main shaft and held movably in the radial direction.
The number of claw members is generally three or four.

In the work holding device, it is necessary to move the claw member in the radial direction when the work is attached and detached. There is a work gripper configured to manually move the claw member using a tool such as a wrench called a chuck wrench.
Since it takes a lot of trouble to attach and detach the work, a work gripping device configured to automatically move the claw member is used.

For example, a hydraulic cylinder is arranged on a main shaft of a machine tool such that a piston rod moves coaxially with the main shaft, and the axial movement of the piston rod is controlled by a claw member by utilizing the principle of leverage or the wedge principle. There is a so-called lever-shaped or wedge-shaped work holding device configured to convert the movement into a radial movement. Further, a spiral-shaped guide portion (for example, a groove) is formed on the scroll plate disposed on the rear end side of the claw member, and an engaging portion (for example, a projection) that engages with the guide portion on the rear end surface of the claw member. There is also a so-called scroll-type work holding device in which a scroll plate is formed by rotating a scroll plate with a motor to move a claw member in a radial direction.

However, the above-described work gripping device requires a drive source for moving the claw member in addition to a drive source for rotating the main shaft, so that the configuration of the machine tool including the work gripping device is large. In addition, there is a problem that product costs increase.

Japanese Patent Application Laid-Open No. Hei 8-19903 discloses a work gripping and spindle driving device that can rotate the spindle and drive the claw members by the same drive source. FIG. 4 is a cross-sectional view for explaining the device.
(A) is a cross-sectional view of a headstock 41 of a lathe to which the above-described device is applied, and (b) is a cross-sectional view of a scroll chuck 40 mounted on the headstock 41.

In this apparatus, in order to operate the chuck 40 and grasp a workpiece, hydraulic pressure pressurized from a hydraulic pressure source 42 is introduced into a cylinder 44 from an electromagnetic switching valve 43, and a piston 45 is driven to drive a clamp tooth 46. Positioning pin 47 between teeth
And fix the main shaft 48 so as not to rotate. The movement of the piston 45 at this time is detected by the proximity switch 49. The movement of the piston 45 is detected by the proximity switch 49,
When the clamp of the main shaft 48 is confirmed, the control device issues a start command to the motor 50 to start the motor 50. The output shaft 51 is rotated, and the gear 52 is rotated.

The rotation of the gear 52 causes the ring gear 53 to rotate. When the ring gear 53 is driven to rotate, the internal teeth 5
4 drives the pinion 55 to rotate. Since the pinion 55 and the pinion 56 are integral, the rotation drives the internal teeth 57 to rotate. The scroll plate 58 is rotated by the driving of the internal teeth 57, the master jaw 59 is driven in the radial direction by the rotation of the scroll plate 58, and the workpiece is clamped by the soft jaw 60.

When the main shaft 48 is driven to rotate, hydraulic pressure is introduced into the cylinder 44 so that the pinton 45 is unclamped to release the main shaft 48. Next, when the motor 50 is started and rotated in the same direction as when the workpiece was clamped, the chuck 40 rotates together with the workpiece (therefore, the spindle 48 also rotates), and the workpiece can be cut by the tool rest. Become.

[0010]

In a general lathe, a driving source such as a motor is arranged at the rear end of a main shaft, and power is transmitted from the rear end using a transmission mechanism comprising a plurality of gears, for example. To rotate the main shaft. On the other hand, in the above-described workpiece gripping and spindle drive device, the motor 50 is disposed on the side of the spindle 48 and the ring gear 5 is provided.
The power is transmitted from the distal end side by using a transmission mechanism composed of 3 or the like, and the main shaft 48 is rotationally driven. Therefore, when the above-described work gripping and spindle drive device is applied to an existing lathe, the entire headstock must be changed, which leads to an increase in manufacturing cost and a problem of poor versatility.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and has as its object to improve the versatility of a work which can be mounted on a spindle of an existing machine tool and used. It is to provide a gripping device.

[0012]

Means and Effects for Solving the Problems Claim 1
Is attached to the main body 12 so as to be rotatable about the axis 3a of the main shaft 3, and the main body 12 is coaxially mounted to the main shaft 3 of the machine tool 2 that can be driven forward and reverse. At the front end, a holding member 15 for holding a plurality of claw members 19, 19 arranged at equal intervals around the axis 3a so as to be movable in the radial direction, and at the rear end side of the front end of the holding member 15 The scroll member 2 which is arranged and rotates around the axis 3a in conjunction with the rotation of the main body 12
0, the scroll member 20 has a spiral-shaped guide portion 22 formed around the axis 3a on the front end surface, and the claw member 19 has the rear end surface facing the scroll member 20 on the front end surface. Engaging part 23 engaged with guide part 22
Is further provided with a rotation braking means 29 for allowing or restricting the rotation of the holding member 15 and a connecting / separating means 30 for connecting or separating the holding member 15 and the main body 12 to grip the work W. Therefore, when the claw member 19 is moved, the rotation braking means 29 causes the holding member 15 to move.
Rotation of the scroll member 20 by rotation of the main shaft 3 in a state where the holding member 15 and the main body 12 are separated by the connection / separation means 30, while rotating the gripped work W. The rotation braking means 29 allows the holding member 15 to rotate, and the connection / separation means 30 connects the holding member 15 and the main body 12 to each other. It is characterized in that the holding member 15 is configured to rotate.

In the work holding device according to the first aspect, when the claw member 19 is moved to hold the work W,
The rotation of the holding member 15 is restricted, and the holding member 15 and the main body 12 are separated. In this state, when the main shaft 3 is rotated, the main body 12 is rotated, but the holding member 15 is not rotated. Then, the scroll member 20 rotates in conjunction with the rotation of the main body 12. The engagement portion 23 of the claw member 19 is engaged with the guide portion 22 of the scroll member 20, and the rotation position of the scroll member 20 causes the engagement position of the engagement portion 23 with the guide portion 22 along the guide portion 22. Move. The claw member 19 is held so as to be movable only in the radial direction, and the guide portion 22 is formed in a spiral shape about the axis 3a. Moving. Therefore, when gripping the work W in the outside gripping mode, first, the main shaft 3 is rotated in a specific direction to move the claw member 19 outward in the radial direction. Then, after arranging the work W near the center of the front end of the holding member 15, the main shaft 3 is rotated in the opposite direction to move the claw member 19 toward the radially inward side, that is, toward the center, thereby gripping the work W. I do. On the other hand, when gripping the workpiece W in the lining mode, the direction of the claw member 19 is reversed from that in the external gripping mode, and the operation is also performed in reverse.

On the other hand, when rotating the gripped work W, the rotation of the holding member 15 is allowed and the holding member 1 is rotated.
5 and the main body 12 are connected. In this state, when the main shaft 3 is rotated, the main body 12 is rotated, and the holding member 15 is also rotated integrally with the main body 12. Therefore, the holding member 1
The work W gripped by 5 also rotates.

As described above, the pawl member 19 is moved by using the rotational force of the main shaft 3 provided in the machine tool 2, so that the work W can be moved only by attaching the work holding device to the main shaft 3.
Can be held and rotated. Therefore, the present invention can be easily applied to the main spindle 3 of the existing machine tool 2, and a highly versatile work holding device can be realized. In addition, since a dedicated driving source for moving the claw member 19 is not required, the configuration can be made with a simple structure and the size can be reduced. Further, by increasing the length of the guide portion 22 by enlarging the scroll member 20, the moving distance of the claw member 19 increases, so that the range of the outer diameter or the inner diameter of the work W that can be gripped by one type of claw member 19 is reduced. Can be expanded. Further, by controlling the torque of the main shaft 3, the gripping force of the work W by the claw member 19 can be changed, so that the work W can be gripped with the optimal gripping force. In particular, even with a work W that is easily deformable like a thin-walled cylindrical part, it can be gripped without being deformed by controlling the gripping force and can be precisely centered. Accuracy can be improved.

The work gripping device according to a second aspect is characterized in that the main shaft 3 is provided with a hydraulic cylinder 5, and the connection / separation means 30 operates using the hydraulic cylinder 5 as a drive source.

In the work holding device of the second aspect, the hydraulic cylinder 5 provided in the main shaft 3 of the machine tool 2 in advance is used as a drive source of the connection / separation means 30. in this way,
Since the configuration and functions provided in the machine tool 2 are used in advance, there is almost no need to remodel the machine tool 2 or the like, and the present invention can be applied at low cost. Also, machine tool 2
By using the configuration on the side, etc., it is possible to simplify the configuration, reduce the size, and reduce the weight of the work holding device.

Further, the work gripping device according to a third aspect of the present invention is characterized in that the work gripping device is provided with speed change means 24 for changing the speed of rotation of the main body 12 and transmitting the speed to the scroll member 20.

According to the third aspect of the present invention, the rotation of the main body 12 is transmitted to the scroll member 20 at a variable speed.
Accordingly, the rotation of the main body 12 is reduced to reduce the scroll member 20.
, The rotation angle of the scroll member 20 can be controlled with a control amount smaller than the minimum control amount of the rotation angle of the main shaft 3 of the machine tool 2, so that the positioning accuracy when the claw member 19 is moved can be improved. it can. This is effective when gripping the work W. On the other hand, if the rotation of the main body 12 is increased and transmitted to the scroll member 20, the scroll member 20 rotates faster than the main shaft 3, so that the claw member 19 can be moved faster. This is effective when removing the work W. When rotating the gripped work W, if the rotation of the main body 12 is transmitted to the scroll member 20 at the same speed, the scroll member 20 rotates at the same speed as the holding member 15 and the claw member 19 does not move. The work W does not come off or an excessive gripping force acts on the work W.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a specific embodiment of a work holding device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a side sectional view of a work holding device 1 according to an embodiment of the present invention, FIG. 2 is a front view of the work holding device 1, and FIG. It is a perspective view showing a state.

As shown in FIG. 3, the work holding device 1
It is used by being attached to the tip of the main shaft 3 of the lathe 2. Spindle 3
Is mounted on the headstock 4 and is driven to rotate about the axis 3a by a drive mechanism (not shown). The main shaft 3 is a cylindrical member. A connecting rod 6 is inserted through the main shaft 3, and a rotary cylinder 5 is disposed on the base end side. The rotary cylinder 5 and the connecting rod 6 are connected to each other. Further, a rotary joint 7 is attached to the rear end of the rotary cylinder 5.
Hydraulic hoses 8 are connected to the rotary joint 7. The operating oil from a hydraulic source (not shown) is supplied to the switching valve 9.
And the hydraulic hoses 8, 8 are supplied to the rotary cylinder 5. The rotary cylinder 5 moves the connecting rod 6 forward or rearward in response to switching of the operation lever 10 of the switching valve 9.

Next, a specific configuration of the work holding device 1 will be described with reference to FIG. The work holding device 1
A main body 12 is coaxially attached to the tip of the main shaft 3 by a plurality of mounting bolts 11. An outer cylinder 14 is attached to the main body 12 using a bearing 13 so as to be rotatable around an axis 12a of the main body 12 (the axis 3a of the main shaft 3). The outer cylinder 14 is integrally formed by connecting a holding member 15 disposed on the distal end side of the main body 12 and a cylindrical member 16 disposed on the proximal end side of the main body 12 with a plurality of fixing bolts 17. Have been.

The holding member 15 has a plurality of (three in this embodiment) grooves 18, 18, 18 at its tip (see FIG. 2). Each groove 18 extends in the radial direction around the line 12a of the main body 12, and is formed such that its forming direction is equally spaced (120 ° in the present embodiment). Each groove 18 has a claw member 19.
Are fitted so as to be slidable along the longitudinal direction. Accordingly, the holding member 15 holds three claw members 19 arranged at equal intervals around the axis 12 at the distal end thereof so as to be movable in the radial direction.

The claw member 19 has a base jaw 19a fitted into the groove 18 and a top jaw 1 fixed to a front end surface of the base jaw 19a by a mounting bolt (not shown).
9b. The top jaw 19b has a plurality of contact surfaces S1 and S2 that contact the work W on the radially inner side. The contact surfaces S1 and S2 are formed at positions where the distance from the axis 12a of the main body 12 is different from each other. Therefore, when gripping the work W, the position in the radial direction of the claw member 19 and the contact surface with which the work W is brought into contact are selected according to the outer diameter of the work W. Also, top jaw 19b
Can be gripped by gripping a workpiece W having a larger outer diameter or a workpiece W having a smaller outer diameter by exchanging the workpiece W with another type, that is, a workpiece having a different position of the contact surface when fixed to the base jaw 19a. it can.

On the rear end side of the holding member 15 from the front end, a scroll member 20 is attached to the front end of the main body 12 by a bearing 21 so as to be rotatable around the axis 12a. The scroll member 20 has scroll teeth 22 on its distal end surface, which are spiral-shaped guides around the axis 12a. On the other hand, the base jaw 19 a of the claw member 19 has a plurality of rack teeth 23.
23 are formed along the radial direction. Therefore, if the scroll member 20 is rotated with the outer cylinder 14 including the holding member 15 fixed, the claw member 19 moves in the radial direction.

Further, a speed reducer 24 is provided between the scroll member 20 and the main body 12. Accordingly, the scroll member 20 rotates at a speed lower than the rotation speed of the main body 12 in conjunction with the rotation of the main body 12. In this embodiment,
The speed reducer 24 is composed of a harmonic drive (registered trademark). That is, the wave generator 25 serving as the input shaft is fixed to the main body 12, the circular spline 26 serving as the fixed shaft is fixed to the outer cylinder 14, and the flex spline 27 serving as the output shaft is connected to the wave generator 25 and the circular generator. Each of the splines 26 meshes with the spline 26 and is fixed to the rear end of the scroll member 20 by mounting bolts 28. Therefore, when the wave generator 25 (the main body 12) is rotated while the circular spline 26 (the outer cylinder 14) is fixed, the flex spline 27 (the scroll member 2) is rotated.
0) rotates at a lower speed than the wave generator 25. The circular spline 26 is connected to the holding member 15.
And a cylindrical member 16, which is fixed by fixing bolts 17.

The upper surface 2a of the lathe 2 and the outer cylinder 1
The outer cylinder 1 is located at a position close to the outer peripheral surface of the cylindrical member 16 of FIG.
A rotation braking means 29 for permitting or restricting the rotation of the fourth rotation is disposed. The rotation braking means 29 includes an outer cylinder detent pin 29.
a, and a pin operating cylinder 29b for projecting or retracting the outer cylinder detent pin 29a toward the outer peripheral surface of the outer cylinder 14. A concave portion 16 is formed on the outer peripheral portion of the cylindrical member 16.
The rotation of the outer cylinder 14 is limited by fitting the outer cylinder rotation stop pin 29a into the recess 16a, while the outer cylinder 14 is removed by removing the outer cylinder rotation stop pin 29a from the recess 16a. Rotation is allowed.

Further, the outer cylinder 1 is provided inside the cylindrical member 16.
A connecting / separating means 30 for connecting or separating the main body 4 and the main body 12 is provided. The connection / separation means 30 includes a cone brake plate 31, a brake operation connection member 32, and a brake plate support pin 33 for connecting these members. The cone brake plate 31 is disposed in a storage space 34 formed between the main body 12 and the tubular member 16, and is inserted movably along the main body 12 while inserting the main body 12 therein. The surface 31a is a pressure contact surface that is pressed against the outer cylinder 14 (the cylindrical member 16), and the pressure contact surface 31a is inclined so that the outer diameter decreases toward the distal end side. In addition, the brake operating connection member 32 is disposed in a storage space 35 formed between the main body 12 and the main shaft 3 on the front end side of the main shaft 3, and the front end of the connection rod 6 is fixed by a mounting bolt 36. Fixed to the part.

Then, the brake plate support pins 33, 33
Is extended from the storage space 34 to the storage space 35 in parallel with the axis 12a and penetrates the main body 12. At the end on the storage space 35 side, the brake operating connecting member 32 is attached by mounting bolts 38, 38. The cone brake plate 31 is fixed to the end on the storage space 34 side by mounting bolts 37, 37. As a result, the connection / separation means 30 advances toward the distal end or retracts toward the main shaft 3 as the connection rod 6 advances or retreats. When the main shaft 3 rotates, the connection / separation means 30 rotates integrally with the main body 12.

On the other hand, in the cylindrical member 16, the inner peripheral surface 16b facing the pressure contact surface 31a of the cone brake plate 31 is
It is inclined so that the inner diameter becomes smaller toward the distal end side, and forms a tapered structure with the press contact surface 31a. Therefore, the connection / separation means 30 is advanced, and the pressure contact surface 31 a of the cone brake plate 31 is moved to the inner peripheral surface 16 of the cylindrical member 16.
In the state of being pressed against b, the connection / separation means 30 and the outer cylinder 14 are integrally rotatable by frictional resistance between the pressed surfaces. Then, as described above, the connection / separation means 3
Since 0 rotates integrally with the main body 12, the main body 12 and the outer cylinder 14 rotate integrally. In addition, the connection / separation means 30 is retracted so that the pressure contact surface 31 of the cone brake plate 31 is moved.
In a state where a is separated from the inner peripheral surface 16b of the cylindrical member 16, the main body 12 and the outer cylinder 14 are separated.

The operation of the work gripping device 1 will be described. First, when gripping the work W, the outer shaft rotation stopping pin 29a of the rotation braking means 29 was aligned with the concave portion 16a of the cylindrical member 16 while rotating the main shaft 3 to rotate the work gripping device 1. Later, outer cylinder detent pin 2
9a is fitted into the recess 16a to restrict the rotation of the outer cylinder 14, and the connecting / separating means 30 is retracted toward the main shaft 3 to separate the outer cylinder 14 from the main body 12. In this state, when the main shaft 3 is rotated, the main body 12 rotates, but the outer cylinder 14 does not rotate, and the scroll member 20 rotates in conjunction with the rotation of the main body 12. The rack teeth 23 of the claw member 19 mesh with the scroll teeth 22 of the scroll member 20, and when the scroll member 20 rotates, the meshing position of the rack teeth 23 with respect to the scroll teeth 22 moves along the scroll teeth 22. I do. The claw member 19 is held by the outer cylinder 14 so as to be movable only in the radial direction, and the scroll teeth 22 are formed in a spiral shape around the axis 12 a of the main body 12. It moves in the radial direction according to the rotation of 20.

Therefore, when gripping the work W, first, the main shaft 3 is rotated in a specific direction to move the claw member 19 outward in the radial direction. Then, after arranging the work W near the center of the distal end portion of the outer cylinder 14, the main shaft 3 is rotated in the reverse direction to move the claw member 19 radially inward, that is, toward the center, so that the contact surface The workpiece W is gripped by bringing S1 or S2 into contact with the outer peripheral surface of the workpiece W. If the outer diameter of the workpiece W is small, the inner contact surface S1 may be used, and if the outer diameter is large, the outer contact surface S2 may be used.

On the other hand, when rotating the gripped work W, the outer cylinder detent pin 29a of the rotation braking means 29 is withdrawn from the concave portion 16a of the cylindrical member 16 to allow the rotation of the outer cylinder 14, and the coupling / separating means is provided. The outer cylinder 14 and the main body 12 are connected by advancing 30 to the distal end side. In this state, when the main shaft 3 is rotated, the main body 12 is rotated and the main body 1 is rotated.
The outer cylinder 14 also rotates integrally with the outer cylinder 2. Therefore, the outer cylinder 1
The work W gripped by 4 also rotates. Then, a desired cutting process is performed on the work W by a cutting tool (not shown).

A speed reducer 24 is interposed between the main body 12 and the scroll member 20, and this speed reducer 24 is constituted by a harmonic drive.
When the outer cylinder 2 and the outer cylinder 14 rotate integrally, the circular spline 26 serving as a fixed axis rotates integrally with the outer cylinder 14, and the wave generator 25
And the rotation speed is the same. Therefore, the speed reducer 24 does not function, and the scroll member 20 rotates at the same speed as the outer cylinder 14 and the claw member 19 does not move. Therefore, the work W falls off or an excessive gripping force acts on the work W. Never.

As described above, according to the present embodiment, the claw member 19 is moved by using the rotational force of the main shaft 3 provided in the lathe 2, so that the work gripping device 1 is simply mounted on the main shaft 3. Thus, the work W can be gripped and rotated. Therefore, it can be easily applied to the main spindle 3 of the existing lathe 2, and the work gripping device 1 excellent in versatility can be realized.

Further, since a dedicated driving source for moving the claw member 19 is not required, it is possible to realize a simple structure and to reduce the size.

Further, by increasing the outer diameter of the scroll member 20 to extend the length of the scroll teeth 22,
Since the moving distance of the claw member 19 becomes longer, the range of the outer diameter of the work W that can be gripped by one type of top jaw 19a can be expanded. Thereby, the types of top jaws prepared in advance corresponding to the outer diameter of the work W are reduced, and the cost can be reduced. Further, the frequency of performing the replacement work of the top jaw is reduced, the burden on the operator is reduced, and the working efficiency can be improved.

Further, by controlling the torque of the main shaft 3, the gripping force of the work W by the claw member 19 can be changed, so that the work W can be gripped with an optimum gripping force. In particular, even for a work W that is easily deformable such as a thin-walled cylindrical part, by controlling the gripping force, the workpiece can be gripped without being deformed and highly accurate centering can be performed. Can be improved.

Further, since the rotary cylinder 5 provided in the lathe 2 is used as a drive source of the connection / separation means 30, there is almost no need to remodel the lathe 2 or the like, and the work gripping device 1 can be applied at low cost. can do. Further, by using the rotary cylinder 5 on the lathe 2 side, the configuration of the work gripping device 1 can be simplified, reduced in size and reduced in weight.

Since the scroll member 20 is rotated at a speed lower than the rotation speed of the main shaft 3 (main body 12), the scroll member 20 is controlled with a control amount smaller than the minimum control amount of the rotation angle of the main shaft 3 of the lathe 2. Since the rotation angle of 20 can be controlled, the positioning accuracy when moving the claw member 19 can be improved. This is effective when gripping the work W.

It should be noted that a speed-increasing gear may be used instead of the speed reducer 24. In this case, since the scroll member 20 rotates at a speed higher than the rotation speed of the main body 12, the claw member 19 can be moved quickly. This is effective when removing the work W.

In the present embodiment, the work W is gripped outside. However, when the work W is lined, the direction of the claw member 19 (top jaw) is reversed, and the operation is reverse to that of the outside grip. By doing so, a lining mode is obtained.
Needless to say, the same effect as that obtained by the outer grip can be obtained.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a work holding device according to an embodiment of the present invention.

FIG. 2 is a front view of the work holding device.

FIG. 3 is a perspective view showing a state where the work holding device is mounted on a lathe.

FIG. 4 is a cross-sectional view showing a conventional technique, in which (a) shows a headstock of a lathe and (b) shows a scroll chuck.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Work holding apparatus 2 Lathe 3 Main shaft 3a Axis 5 Rotating cylinder 6 Connecting rod 12 Main body 12a Axis 14 Outer cylinder 15 Holding member 16 Cylindrical member 16a Depression 19 Claw member 20 Scroll member 22 Scroll teeth 23 Rack teeth 24 Reduction gear 25 Wave generator Reference Signs List 26 circular spline 27 flex spline 29 rotation braking means 29a outer cylinder rotation stop pin 29b pin operation cylinder 30 connection / separation means 31 cone brake plate 32 brake operation connection member 33 brake plate support pin W work

Claims (3)

[Claims] 1. A main body (12) coaxially mounted on a main shaft (3) of a machine tool (2) that can be driven forward and reverse, and the main body rotatable about an axis (3a) of the main shaft (3). (1
2) and the axis (3)
a) A plurality of claw members (19 ·
19) holding member (1) for movably holding in the radial direction.
5) and a scroll member (2) which is arranged on the rear end side of the front end of the holding member (15) and rotates around the axis (3a) in conjunction with the rotation of the main body (12).
0), and the scroll member (20) has a spiral-shaped guide portion (2) centered on the axis (3a) on the distal end surface.
2), the claw member (19) has a guide portion (2) on its rear end face facing the scroll member (20).
2) forming an engaging portion (23) to be engaged with, and further a rotation braking means (29) for allowing or restricting the rotation of the holding member (15); the holding member (15) and the body ( 1
And (2) connecting and separating the work (W) and the claw member (19) for gripping the work (W).
Is moved, the rotation of the holding member (15) is limited by the rotation braking means (29), and the holding member (15) and the main body (1) are connected by the connection / separation means (30).
While the scroll member (20) is rotated by the rotation of the main shaft (3) in a state where 2) and (2) are separated, when the gripped work (W) is rotated, the holding member is rotated by the rotation braking means (29). The rotation of (15) is permitted, and the holding member (15) is connected by the connection / separation means (30).
And the main shaft (3) in a state where the main shaft (3)
A workpiece gripping device characterized in that the holding member (15) is rotated together with the main body (12) by the rotation of. 2. The device according to claim 1, wherein said main shaft is provided with a hydraulic cylinder, and said connecting / disconnecting means is operated by using said hydraulic cylinder as a drive source. Work holding device. 3. The work gripping device according to claim 1, further comprising a speed change means (24) for changing the speed of rotation of the main body (12) and transmitting the speed to the scroll member (20).