JPS624404Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a chuck that can automatically handle a wide range of workpieces of different diameters machined by machine tools.

The amount of movement of the master yaw in the power chuck is the amount necessary to replace and grip the same workpiece, and when the diameter of the workpiece is changed beyond this movement, it is normal to remove the top yaw from the master yaw and replace it. be. For example, in Japanese Patent Application Laid-Open No. 54-45880, the outer position of the master yaws is individually adjusted manually in a device in which a double master yaw is provided. For this reason, the response was difficult and time-consuming. In recent years, numerically controlled machine tools have become widespread in factories, and in addition to the high precision of these machine tools, the reliability of control devices has been significantly improved, leading to continuous unmanned operation. However, in order to be unmanned for a long time, it must be possible to completely handle various types of workpieces. One of the demands for this is an automated wide-area chuck that can handle workpieces of different diameters.

This invention was made in response to the above-mentioned circumstances and provides a chuck that can automatically and quickly change the diameter of workpieces of different diameters. That is, the master yaw of the power chuck is separated into two and has a double structure that can be moved independently, and the first master yaw is interposed between the opposing surfaces of the first and second master yaws so that there is no gap in the axial direction. The second master yaw rotates with the threaded screw and is movable in the axial direction.The drive shaft is connected to a rotary shaft for adjusting the diameter and rotated by a drive source, and the radial position of the top yaw is set according to the rotation axis. The amount of movement of the member that is displaced in the axial direction as it rotates is detected by a position detector, and the diameter is compared with the diameter of the next workpiece based on a command, and the diameter is automatically changed based on the judgment result.

Embodiments of this invention will be described below based on the drawings. For example, a main shaft 3 supported by a bearing 2 on a head stock 1 of a lathe has a chuck main body 4 secured to the front end surface thereof, centered by a shot taper. The chuck main body 4 has three open-headed grooves 5 cut out radially at equal angles from the center hole. A first master yo 6 is fitted in the inner cross groove 5a so that it can only slide, and a second master yo 7 can slide in the outer cross groove 5b in the same direction as shown in FIG. Fitted in condition.

A substantially semi-cylindrical recess 6a having an axis in the radial direction is cut into the joint surface side of the first master yo 6, and a recess 6a having an axis in the radial direction centered on the joint surface is cut into the second master yo 7. A female thread 7a is provided around half the circumference. A male screw 8 having a length with no gap in the axial direction is housed in the recess 6a in a meshing state with the semi-female screw 7a. A spline hole 8a is cut in the center of this male thread, and a spline drive shaft 10 which is supported by the chuck body 4 and has a bevel gear 9 fixed to the chuck center side is fitted therein. Therefore, when this spline drive shaft is rotated, the second master yaw 7 is moved in the radial direction with respect to the first master yaw 6 because the male screw 8 is fixed on the side surface of the recess 6a. The second master yaw 7 has a replaceable top yaw 11 fastened to its upper surface. T-grooves with the same inclination are cut in the center-side end surface of the first master yaw 6, and the main shaft side is inclined to open outward. An engaging ring 12 is connected to the tip of a draw tube 13 that passes through the center of the main shaft 3.
On the other hand, a hydraulic cylinder 14 is fixed to the rear end of the main shaft 3, and a hollow piston rod of a piston 15 fitted in this cylinder is connected to the draw tube 13. and hydraulic cylinder 14
Pressure oil is supplied and discharged through oil passages 17a and 17b of a rotary joint 17 provided on a bracket 16 of the headstock 1. On the other hand, the bevel gears 9 of the three drive shafts 10 and the bevel gears 18 supported at the center of the meshing chuck body 4 are connected to a rotating shaft 19 passing through the center of the draw tube 13. A gear 20 is fixed to the rear end of the rotating shaft 19, and meshes with a gear 23 of an output shaft of a servo motor 22 provided on a bracket 21 protruding from the rear end of the headstock 1. A clutch 24 is interposed between the output shaft of the servo motor 22 and connects or disconnects the power line according to a command.
Further, between the rear rotary joint 17 of the rotary shaft 19 and the gear 20, a female thread is fitted with a key so as to be movable on the shaft, and the outer thread thereof is fixed concentrically to the rear end of the hydraulic cylinder 14. There is a displacement body 25 that is screwed into the thread of the cylindrical body 26. Therefore, when the rotating shaft is rotated, the displacement body 25 is moved in the axial direction along with the rotation. A bearing 27 is provided on the outside of the displacement body 25.
The screw rack body 28 is supported by the bracket 21.
It is prevented from rotating by , and is displaced by the same amount as the displacement body 25 moves in the axial direction. A pinion 30 of a position detector 29 is engaged with this screw rack body 28.
It is designed to detect the amount of displacement. Therefore, the value of the diameter of the workpiece gripped by the top jaw 11 is output from the position detector 29. Also, rotation axis 1
The boss 19a provided on the bevel gear 18 side of 9 and the engagement ring 1
A disc spring 31 is interposed between the draw tube 13 and the fixing portion of the draw tube 2, and when the draw tube 13 is pulled to grip a workpiece, the disc spring 31 is compressed and the rotary shaft 19 is rotated integrally with the draw tube 13. 32 is a switching valve for oil passages 17a and 17b to the hydraulic cylinder 14.

In FIG. 3 showing the control circuit, 40 is an input dial for the diameter of various workpieces, 41 is a storage device for input diameters, and 42 is a readout circuit for reading out the next workpiece diameter from the storage device 41 in response to a command for machining workpieces of different diameters. , 43 is a comparison circuit that compares the current grasping diameter, which is the output of the position detector, with the read workpiece diameter, and when they do not match, it determines whether the motor is running in the forward or reverse direction, outputs the output, and connects the clutch 24. When they match, a signal is output to stop the motor and shut off the clutch. 44 is a servo motor drive circuit.

When the top jaw 11 is currently open, when a number indicating the type of workpiece to be gripped next (the diameter is larger than the current one) is commanded, the readout circuit 42
The workpiece diameter corresponding to that number is read out from the storage device 41 by . On the other hand, the current diameter of the workpiece of the top jaw 11 is outputted by the position detector 29, and is compared in the comparator circuit 43. As a result, a drive command in the + direction, that is, a direction in which the top gear 11 is expanded, is output, and a command to connect the clutch 24 is also output. With this command, the motor is rotated forward by the output of the servo motor drive circuit 44, and the gear 2
3.20, the drive shaft 10 is rotated via the rotating shaft 19 and the bevel gears 18.9, the male screw 8 is rotated, and the second
The master yaw 7 is moved outwardly with respect to the first master yaw together with the top yaw. On the other hand, as the rotating shaft 19 rotates, the displacement body 25 screwed into the screw of the internally threaded cylindrical body 26 is rotated and displaced in the axial direction, and this displacement causes the screw rack body 28, whose rotation is prevented by a bracket, to be rotated and displaced in the axial direction. replaced by displacement,
As the pinion 30 meshes with the screw rack rotates, the position detector 29 outputs a diameter value based on the amount of movement of the top gear 11, and when the comparison circuit 43 determines that they match, a signal is sent to stop the servo motor and shut off the clutch. At this point, the clutch 24 is commanded to be disconnected, and the output of the servo motor drive circuit 44 is stopped. When a clutch cutoff signal is output from a switch (not shown), the workpiece is sent from the loader to the chuck, and the switching valve 32 is switched to open the oil passage 17b.
Oil is sent to the front chamber of the cylinder 14 via the rotary joint 17, causing the piston 15 to move to the left. As a result, the draw tube 13 is pulled, the engagement ring 12 pulls the first master yaw 6 inward, and the second
The master yaw 7 and top yaw 11 grip the workpiece and compress the disc spring 31 to
9 and draw tube 13 are integrated to prevent loosening of the top jaw and movement of the displacement body due to rotation of the chuck.

As detailed above, this invention provides a second master yaw superimposed on the first master yaw so that they can move together or move independently, and compare the current diameter and the next diameter of the second master yaw. Now it is possible to adjust automatically while
This eliminates the need for individual adjustment of the top slider and allows the grasping diameter to be widened, which is extremely effective in achieving unmanned mixed production of workpieces with different diameters.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the present invention, FIG. 2 is a sectional view taken along the line -- in FIG. 1, and FIG. 3 is a control block diagram. 3...Main shaft, 4...Chuck body, 6...First
Master station, 7...Second master station, 8...
Screw, 10... Drive shaft, 13... Draw tube, 14... Hydraulic cylinder, 19... Rotating shaft, 2
2... Servo motor, 24... Clutch, 25...
... Displacement body, 29 ... Position detector, 40 ... Workpiece diameter input dial, 41 ... Memory device, 42 ... Readout circuit, 43 ... Comparison circuit.

Claims (1)

[Scope of utility model registration request] A plurality of first master yaws are installed on the front end of the main shaft so as to be movable only in the radial direction, and the plurality of first master yaws inserted through the center of the main shaft are simultaneously moved by an equal amount in the radial direction. a drive device for moving the draw tube in the axial direction in response to a workpiece gripping command; A second master yaw is provided on the chuck body and has a top yaw fixed to the front surface thereof, and a recess in the axial direction cut into the second master yaw side of the first master yaw restricts the axial movement, and the circumferential direction of the second master yaw is regulated. The half of the screw is retracted and is provided in the radial direction at the boundary between the first and second master yos so as to be screwed into a semi-cylindrical female screw cut in the axial direction on the first master yo side of the second master yo. a screw, a drive shaft that rotates together with the screw and is provided in a radial direction to allow movement of the screw in the axial direction; and a rotation shaft that is inserted into the draw tube and rotates the drive shaft. , a motor that drives the rotating shaft, a clutch that connects the power line of the motor in response to a workpiece grip diameter change command, and a displacement body that is moved in the axial direction as the rotating shaft rotates;
a position detector for detecting the position of the second master yaw by detecting the amount of movement of the displacement body in the axial direction; a storage means for storing various workpiece diameters; Compares the value of the workpiece diameter read by the diameter change command with the current gripping diameter of the second master yaw, which is the output of the position detector, outputs the result, and also outputs a signal that determines the moving direction of the second master yaw. A power chuck for wide area grasping, comprising a comparison circuit that operates the clutch and the motor based on the output signal.