JP4167384B2 - Work clamp mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a work clamp mechanism for a lathe spindle.
[0002]
[Prior art]
A conventional work clamping mechanism will be described with reference to FIG.
In FIG. 2, a stator 52 of the electric motor is fixed to the spindle housing 51. A rotating part 56 integral with the rotor 55 of the electric motor is rotatably supported by the stator 52 via bearings 53 and 54. A master jaw 58 is disposed inside the chuck 57 attached to the rotating portion 56, and a claw 59 for grasping the workpiece is attached to the master jaw 58.
On the other hand, the draw bar 60 and the plunger 61 are integrally fixed via screws, and the master jaw 58 and the plunger 61 are slidably tapered and driven by the draw bar 60 in the direction of the main shaft. The attached claw 59 is arranged so that it can be opened and closed.
A hydraulic piston 61 and a hydraulic cylinder 62 for driving the draw bar 60 are arranged at the rear of the main shaft. The hydraulic cylinder 62 is fixed to the rotating unit 56 and rotates together with the rotating unit 56. Oil is supplied to the hydraulic cylinder 62 through a fluid coupling 64 from an oil injection flange 63 fixed to the spindle housing 51.
[0003]
Next, a series of work clamping operations of the work clamping mechanism according to the conventional technique will be described.
When the workpiece is clamped, oil is supplied to the hydraulic cylinder 62 disposed at the rear part of the main shaft via a fluid coupling, and the draw bar 60 is driven toward the rear portion of the main shaft. When the plunger 61 coupled to the draw bar 60 is pulled to the rear part of the main shaft, the master jaw 58 tapered to the plunger 61 moves toward the center of the main shaft, and the claw 59 attached to the master jaw 58 grasps the workpiece. . Further, the gripping force of the workpiece is a gripping force corresponding to the hydraulic pressure acting on the piston.
The lathe spindle mechanism disclosed in FIG. 2 is a mechanism that is most commonly used in NC lathes that are currently manufactured, and the configuration thereof is that a built-in motor is employed and the draw bar 60 is retracted. In other words, a general-purpose chuck that opens and closes the claw 59 is employed.
[0004]
[Problems to be solved by the invention]
However, the above prior art has the following problems.
[0005]
In order to maintain the gripping force of the workpiece, it is necessary to constantly generate the hydraulic pressure supplied to the hydraulic cylinder. For this reason, there is a problem that the power consumption of the lathe increases because the hydraulic unit must always be operated. In addition, since the waste heat of the hydraulic unit warms the machine, the machining accuracy deteriorates. In addition, the noise of the hydraulic unit is large, which causes the working environment to deteriorate. Furthermore, since the grasping force adjustment is performed by adjusting the valve of the hydraulic unit, the automatic grasping program cannot be set in the automatic operation program, which hinders automatic machining.
[0006]
In addition, as a condition required for the work clamping apparatus, (1) a general-purpose chuck generally owned by a lathe user can be used, and no new investment such as purchasing a special chuck is required. (2) The built-in motor configuration is capable of cutting workpieces with high accuracy without vibrations caused by gears. (3) There are three points that it is an inexpensive configuration that does not require the second motor for driving the draw bar.
[0007]
The present invention solves the above-described problems. By eliminating the hydraulic unit, power consumption is reduced, machining accuracy is improved, noise is improved in the work environment, and optimum workpiece grasping is performed without stopping automatic operation. A work clamping mechanism that can be applied to a lathe spindle mechanism that uses a built-in motor and a general-purpose chuck, and that does not require a second electric motor for driving the draw bar. The purpose is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a work clamping device according to the present invention comprises a chuck attached to the tip of a spindle, a spindle housing for fixing a stator of an electric motor, and a rotation having a female screw fixed to the rotor of the electric motor and having an inner diameter. , A draw bar in which an external thread fitted to the female screw is arranged on the outer diameter, a claw that opens and closes by driving the draw bar in the direction of the main shaft and grasps the workpiece, and is connected to the chuck in the previous period, and the main shaft housing And an armature 1 that is switched and coupled to any one of the rotating parts, and the rotation of the chuck with respect to the spindle casing is restricted by being coupled to the spindle casing, and the armature 1 is coupled to the rotating section by being coupled to the rotating section. An armature 1 that allows rotation of the chuck with respect to the spindle housing, coupled to the draw bar, and the spindle housing and the rotating portion While the A armature 2 which is also coupled to switch or, with respect to the spindle housing to restrict the rotation relative to the spindle housing of the drawbar by coupling, spindle housing of the drawbar by binding to the rotating part An armature 2 that allows rotation, and two armature switching mechanisms for coupling the armature 1 and the armature 2 to either the fixed portion or the rotating portion, respectively. .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0010]
In FIG. 1, a stator 2 of an electric motor is fixed to a spindle housing 1. A rotating portion 7 integral with the rotor 6 of the electric motor is rotatably supported on the stator 2 via bearings 3, 4, and 5. A chuck 9 is fixed to the collar 8 to which the bearings 3 and 4 are attached. A master jaw 10 is disposed inside the chuck 9, and a claw 11 for grasping a workpiece is attached to the master jaw 10. In addition, a female screw 12 is processed on the inner diameter of the rotating portion 7, and a draw bar 14 in which an male screw 13 combined with the female screw 12 is processed on the outer diameter is disposed on the inner diameter of the rotating portion 7. Further, the draw bar 14 and the plunger 15 are constrained in the main shaft direction via a thrust bearing 16. The master jaw 10 and the plunger 15 are slidably tapered and are arranged so that the claw 11 attached to the plunger 15 can be opened and closed by driving the draw bar 14 in the main shaft direction.
On the other hand, an armature 17 meshed with a spline 24 processed to the outer diameter of the collar 8 is disposed at the front of the main shaft, and a brake disk 18 and a claw clutch 19 are disposed at both ends of the armature 17, respectively. Further, the armature is attached to the piston 21 via the bearing 20, and the piston is arranged by a spring 22 and a pneumatic cylinder 23 so as to be drivable in the main shaft direction. In addition, at the rear portion of the main shaft, an armature 26 that is meshed with a spline 25 processed into the draw bar 14 and brake disks 27 and 28 are disposed at both ends of the armature 26, respectively. Further, the armature is attached to the piston 30 via a bearing 29, and the piston is arranged by a spring 31 and a pneumatic cylinder 32 so as to be driven in the main shaft direction.
The rotational direction position of the rotor is detected by a rotational position detector 33 attached to the spindle housing and a detection gear 34 attached to the rotor.
[0011]
Next, a series of work clamping operations of the work clamping mechanism of the present invention will be described.
At the time of workpiece clamping, first, the pneumatic cylinders 23 and 32 are operated to drive the pistons 21 and 30, and the armatures 17 and 26 are fixed to the spindle housing 1 via the brake disks 18 and 27. At this time, the rotational position of the rotor 6 detected by the position detector is stored on the control device side. When the rotor 6 is rotated in this state, the draw bar 14 and the chuck 9 are constrained in the rotational direction with respect to the main shaft casing 1 via the armatures 17 and 26, so that the draw bar 7 is driven in the main shaft direction. . When the rotor 6 is rotated so as to draw the draw bar 7 toward the rear part of the main shaft, the plunger 15 coupled to the draw bar 7 is pulled, and the master jaw 10 taper-coupled to the plunger 15 moves toward the center of the main shaft. Then, the claw 11 attached to the master jaw 10 grasps the workpiece. The clamping force of the workpiece can be set by setting the maximum applied current supplied to the motor on the controller side in advance, so that the generated torque of the motor can be set. Therefore, the workpiece clamping force is set by the lead of the screw 12 and the master jaw 10 taper angle. Is possible.
[0012]
After the workpiece clamping, first, the operation of the pneumatic cylinder 32 is stopped, the armature 26 is driven by the spring 31, and is coupled to the rotating portion 7 via the brake disk 28. Next, when the rotor 6 is rotated and fixed to the spindle housing 1 of the armature 17 at the time of clamping, the rotor 6 is rotated to the rotation direction fixed position stored in the control device. Here, the pneumatic piston 23 is stopped, the piston 21 is driven by the spring 22, and the armature 17 is coupled so that the claw clutch 19 is engaged. Thereby, since the rotation part 7, the chuck | zipper 9, and the draw bar 14 rotate integrally through the armatures 17 and 26, the grasping force of a workpiece | work is maintained.
[0013]
In the above-described embodiment, the claw clutch 19 is used for coupling the armature 17 and the rotating portion 7, but the same effect as the present invention can be obtained even if a brake disk is used instead of the claw clutch 19. .
In this case, it is not particularly necessary to match the rotation position of the chuck 9 with the rotation position of the rotation unit 7. Therefore, after clamping, the armatures 17 and 26 may be simultaneously driven and coupled to the rotation unit 7. Further, since it is not necessary to rotate the draw bar 14 in order to align the rotation position of the claw clutch 19, it is not necessary to attach the thrust bearing 16.
[0014]
In the above embodiment, the armature driving method has been described by using the pneumatic piston. Obtainable.
[0015]
【The invention's effect】
According to the present embodiment, since the workpiece can be clamped without a hydraulic unit, power consumption can be suppressed. Further, since the waste heat of the hydraulic unit does not warm the machine, machining accuracy is improved. Further, the working environment is improved because no noise is generated in the hydraulic unit. Furthermore, since the workpiece grasping force can be set simply by setting the maximum applied current to the electric motor from the control device, it is possible to input it on the program, and the optimum workpiece grasping force can be set without stopping the automatic operation.
Furthermore, since a general-purpose chuck generally owned by a lathe user can be used, no new investment such as purchasing a special chuck occurs. Further, since it corresponds to a built-in motor configuration capable of cutting a workpiece with high accuracy, there is no vibration due to gears and the like, and when the workpiece clamping device of the present invention is applied to a lathe, high-quality cutting can be performed. Further, since the second motor for driving the draw bar is not required, it can be manufactured at low cost.
[Brief description of the drawings]
FIG. 1 is a view showing a workpiece clamping mechanism in an embodiment of the present invention.
FIG. 2 is a view showing a work clamp mechanism according to a conventional technique.
[Explanation of symbols]
1 .. Spindle housing 2.. Stator 3, 4, 5, 20, 29.. Bearing 6, Rotor 7 Rotating part 8 Collar 9 Chuck 10 · Master jaw, 11 · · Claw, 12 · · Female screw, 13 · · Male screw, 14 · · Drawbar, 15 · Plunger, 16 · · Thrust bearing, 17, 26 · · Armature, 18, 27, 28 · · Brake disk, 19 ... Claw clutch, 21, 30 ... Piston, 22, 31 ... Spring, 23, 32 ... Pneumatic cylinder, 24, 25 ... Spline, 33 ... Rotary position detector, 34 ... Detection gear.

Claims (1)

In the main axis of a lathe that is rotated by an electric motor,
A chuck attached to the spindle tip,
A spindle housing for fixing the stator of the electric motor;
A rotating part fixed to the rotor of the electric motor and having a female screw on the inner diameter;
A draw bar in which the male screw fitted to the female screw is arranged on the outer diameter;
A claw that opens and closes by driving the draw bar in the direction of the main shaft and grasps the workpiece,
An armature 1 that is coupled to the chuck and is switched and coupled to either the main spindle housing or the rotating portion, and the chuck rotates relative to the main shaft housing by coupling to the main shaft housing. And the armature 1 that allows the chuck to rotate with respect to the spindle housing by being coupled to the rotating portion;
An armature 2 that is coupled to the draw bar and is switched and coupled to either the spindle housing or the rotating portion, and is coupled to the spindle housing to rotate the draw bar relative to the spindle housing The armature 2 that allows rotation of the draw bar with respect to the spindle housing by coupling to the rotating portion;
Two armature switching mechanisms for coupling the armature 1 and the armature 2 to either the fixed portion or the rotating portion, respectively;
Work clamp mechanism characterized by comprising

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