JP3415174B2 - Spindle braking system for multi-task machine tools - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work spindle braking device in a compound machining machine tool in which the work spindle is rotationally driven and C-axis controlled by a single spindle motor capable of servo control.

[0002]

2. Description of the Related Art In a multi-tasking lathe, a spindle is rotated at a low speed while accurately controlling a rotation angle of a workpiece spindle (hereinafter, simply referred to as a spindle) that grips a workpiece through a chuck, and a rotating tool is used. When machining such as contouring, there is a problem that the C-axis control of the spindle becomes unstable due to fluctuations in the cutting load, and chatter vibration occurs on the spindle. Therefore, in order to maintain a constant load on the spindle motor that drives the spindle to rotate, the spindle lock is originally provided for indexing, in which the spindle is fixed at a fixed angle position and the workpiece is cut with a rotating tool. A torque load was applied by controlling the pressure of the hydraulic pressure supplied to the hydraulic brake.

In addition, instead of the hydraulic brake, there has been proposed a device in which an electric torque applying device such as a torque motor and an electromagnetic powder clutch is separately provided to apply a torque load from the outside (for example, a special feature). Kaihei 3-2811
No. 01 and JP-A-3-281147).

[0004]

However, since all of the above-described conventional torque imparting devices are mounted on the rear portion of the main spindle, chatter vibration due to a cutting load is directly applied to the C-axis when performing machining while controlling the C-axis. Transmitted to the drive motor,
The control rigidity of the C-axis drive motor capable of withstanding chatter vibration has been required. Further, since the main shaft itself is a hollow shaft and has no torsional rigidity, chatter vibration occurs in the rotation direction. The point of torsional rigidity can be solved by increasing the rigidity of the spindle itself, but there was a limit because it was restricted by design such as bearing dimensions, inertia, and through holes. Further, if the main spindle lock hydraulic brake and the torque applying device are separately provided adjacent to each other at the rear portion of the main spindle, there is a problem that the total length of the main spindle becomes long.

The present invention has been proposed in view of the above circumstances, and it is a multi-tasking machine tool in which the overall length of the spindle can be shortened and the C-axis of the spindle can be controlled with high accuracy without being affected by the rigidity of the spindle. An object of the present invention is to provide a spindle braking device in.

In order to achieve the above object, according to the present invention, a brake for locking a spindle is provided at a rear end portion of the work spindle.
And a torque applying device is provided on the outer peripheral portion of the front end of the work spindle.

[0007]

With the above configuration, the variable load (chatter vibration) during cutting that is transmitted to the chuck, the work spindle, and the spindle motor through the work is generated by the torque applying device provided on the outer peripheral portion of the front end of the work spindle near the machining point. Attenuated.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a spindle device of a multi-task machine tool having a spindle braking device according to the present invention.

In the figure, 1 is a headstock, 2 is a spindle case fixed to the headstock 1, 3 is a plurality of bearings 4 on the spindle case 2.
The work spindle is rotatably supported via a rotary drive spindle motor 5 incorporated in the spindle case 2 to directly drive the workpiece spindle. The main shaft 3 is a hollow shaft,
A flange portion 6 is continuously provided at the front end, and the flange portion 6
A chuck 7 for gripping the work W is fixedly attached thereto. Further, a lock brake disc 8 is attached to the rear end of the main shaft 3, and the lock brake disc 8 is clamped and fixed by a brake cylinder 9 mounted on the main shaft case 2 to lock the main shaft 3 at a fixed angular position. It is supposed to do. The rotation angle position of the spindle 3 is detected by the rotation position detector 10 mounted on the rear end of the spindle case 2.

Reference numeral 11 denotes a torque applying device provided on the outer peripheral portion of the front end of the main shaft 3. The torque applying device 11 is provided on a torque applying brake disc 12 fixed to the outer peripheral portion of the flange portion 6 and an annular bracket 13 fixed to the front end surface of the spindle case 2 and surrounding the flange portion 6 and the brake disc 12. And a pair of brake cylinders 14 disposed on both sides of the brake disc 12 and a pair of brake pads 15 disposed so as to face each other with the brake disc 12 sandwiched between the brake cylinders 14. , 15 and. Brake pad 1
5 is slidably supported by a support shaft 16 fixed to an annular bracket 13, and a brake disc 1 is supported by a spring 17.
It is urged to release 2. On the other hand, compressed air is supplied to each brake cylinder 14 from the air supply port 18 through the communication hole 19, and the air pressure presses the brake pad 15 against the brake disc 12 against the spring 17. As a material of the brake pad 15, a metal material having a small change in friction coefficient and excellent in seizure resistance and wear resistance, for example, a copper alloy for metal is desirable. In addition, by periodically injecting lubricating oil into the rotating space 21 of the brake disc 12 from the lubricating oil supply port 20 (see FIG. 2) to suppress the change in the friction coefficient between the brake disc 12 and the brake pad 15, stick-slip is prevented. At the same time as preventing the phenomenon, it reduces the heat generated by the braking operation.
The lubricating oil accumulated in the rotating space 21 is the annular bracket 1.
It is discharged from a discharge port 22 provided in the lower part of 3, and is processed in the processing part of the machine. Further, air is constantly supplied to the rotating space 21 through the purge air supply port 23, and the seal portion 2
4 (see FIG. 2) to prevent chips and cutting oil from entering the rotating space 21 and cool the brake disc 12. The brake cylinders 14, 14 and the brake pads 15, 15 are composed of a plurality of sets, and the brake disc 12
Are assembled to the annular bracket 13 at appropriate intervals in the circumferential direction.

In the spindle device configured as described above, when the spindle motor 5 is controlled by the C-axis to index and position the spindle 3, and when the spindle 3 is rotated at a low speed to feed the workpiece, the torque imparting device 11 is used. To operate. The compressed air supplied from the air supply port 18 through the communication hole 19 is supplied to each brake cylinder 14, presses the brake pad 15 against the brake disc 12 against the spring 17, and sandwiches the brake disc 12 between the brake pads 15 and 15. A torque load is applied to the main shaft 3 by pressing it so as to attach it.
Then, at the same time that the C-axis control of the spindle motor 5 is released, the supply of compressed air is stopped, and the brake pad 15 is separated from the brake disc 12 by the action of the spring 17.

In the above embodiment, an example in which a friction brake is used as the torque applying device 11 is shown, but a torque motor,
An electric torque applying device such as an electromagnetic powder clutch may be used.

[0014]

As described above, according to the present invention,
Fix the work spindle at a fixed angular position and rotate it with a rotary tool.
When cutting a gear, a brake for locking the spindle and torque application
By using the device together, the torsional vibration of the spindle due to machining
Motion can be attenuated.

Further, the fluctuating load (chatter vibration) transmitted to the chuck, the spindle and the motor through the work during cutting is damped by the torque applying device provided on the outer periphery of the front end of the work spindle near the machining point. Therefore, the C-axis control of the spindle can be performed with high accuracy without being affected by the control rigidity of the motor and the torsional rigidity of the spindle itself.

Further , a lock brake and a brake are provided at the rear of the spindle.
Spindle compared to the one with separate luke attachment devices
The total length can be shortened.

Further, as described above, the total length of the main shaft can be shortened.
Therefore , the inertia can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view showing a spindle device section of a combined machining machine tool including a spindle braking device according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the same main part.

[Explanation of symbols]

1 Headstock 2 Spindle case 3 Work spindle 5 Spindle motor 6 Flange 7 chuck 11 Torque imparting device 12 Brake disc for torque application 13 annular bracket 14 Brake cylinder 15 brake pads

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23Q 5/04 B23B 19/02 B23Q 5/54

Claims (3)

(57) [Claims] 1. A composite machining machine tool in which a work spindle for gripping a work via a chuck is index-controlled and / or C-axis controlled by a motor, and a spindle locking brake is provided at a rear end portion of the work spindle.
A spindle braking device for a compound machining machine tool , wherein a torque applying device is provided on the outer peripheral portion of the front end of the work spindle. 2. The spindle braking device for a multi-task machine tool according to claim 1, wherein the torque applying device is a friction brake. 3. The torque applying device is a torque motor,
The spindle braking device for a multi-task machine tool according to claim 1, which is an electric torque applying device such as an electromagnetic powder clutch.