JPS6225281Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drive device for a rotary guide bush that rotates synchronously with the main shaft at the same rotation speed.

Automatic lathes with a guide bushing, especially automatic headstock sliding type automatic lathes, have a guide bushing in front of the main spindle, and can perform heavy cutting by cutting near this guide bushing, and can also cut long and thin parts with high precision. Its greatest feature is that it can be processed. As is well known, there are two types of guide bushes: fixed guide bushes and rotating guide bushes.The former has high rigidity and is capable of high-precision machining, but due to the rotation of the workpiece, the inner surface of the guide bush and the outer circumference of the workpiece It has the disadvantage that it is prone to seizing because slippage occurs between the two. Therefore, in the case of a large-diameter workpiece where the circumferential speed of the workpiece's outer periphery is high, the latter type, that is, a rotating guide bush, is used exclusively.

As long as the rotating guide bushing is properly sealed from the outside world and properly lubricated, seizure should not occur, but in reality, cutting oil and fine chips often flow into the bearing. This results in poor rotation, and if the rotation progresses further, it may eventually lead to seizure and damage to the machine.

The present invention was developed to eliminate these accidents, and includes an intermediate shaft that rotates in synchronization with the main shaft.This intermediate shaft rotates the rotating guide bushing synchronously at the same rotation speed as the main shaft. By providing an overload safety device on the shaft, it is possible to detect malfunction of the rotating guide bushing and stop the operation of the machine, thereby preventing accidents such as seizure.

Hereinafter, the present invention will be explained based on the drawings.

FIG. 1 is a drive system diagram of an NC automatic lathe having a drive device for a rotating guide bush of the present invention, in which the rotation of a motor 1 such as a DC motor or a pulse motor is transmitted to a first intermediate shaft 3 via a belt 2. Ru.

The first intermediate shaft 3 is provided parallel to the main shaft 4, and includes a timing pulley 5, a timing belt 6,
The main shaft 4 is rotationally driven via a timing pulley 7. The first intermediate shaft 3 is formed of a spline, and a pulley 5 is fitted onto the spline to transmit rotation and to be able to slide in the axial direction. The shaft also slides to transmit driving force to the main shaft 4. For sliding movement of the main shaft 4 in the front-rear direction, rotation of the pulse motor 8 is converted into linear motion by a ball screw 9, and the headstock moves along a guideway (not shown). The detailed structure of the main shaft 4 is almost the same as that of the prior art, so it will not be described in detail here.

FIG. 2 shows details of the drive system from the first intermediate gear 3 to the rotary guide bush 15.
A gear 10 is fixed to the end of the intermediate shaft 3 and meshes with a gear 12 provided on the second intermediate shaft 11. A torque limiter 13 is provided between the second intermediate shaft 11 and the gear 12 as an overload safety device, and detects overload and stops the machine. A gear 14 is provided at the other end of the second intermediate shaft 11 and meshes with a gear 16 provided on the rotary guide bush 15 to rotate the rotary guide bush 15.

The housing 17 that rotatably supports the second intermediate shaft 11 is adjustable, and the gears 10, 12, and gear 1
4 and 16 are fixed at a position where they are in a proper meshing state. Here, it is desirable that at least one of the pairs of gears 10 and 12 and gears 14 and 16 be made of plastic to prevent noise generation and reduce inertial force.

The torque limiter 13 is designed to cut off the transmitted torque and cause the pin 18 to protrude when an overload occurs. Therefore, as shown in FIG. 3, the protrusion of the pin 18 can be detected and the machine can be stopped. In this embodiment, the torque limiter 1
Lever 19 that does not operate when pin 18 of 3 is inserted
is rotatably provided around a pivot 20, and this lever 19 is pressed by a pin 18 and rotated counterclockwise to press a limit switch 21 to detect an overload condition. The spring 30 urges the lever 19 to come into contact with the stopper 31, and the leaf spring 32 locks the tip of the lever 19 when the lever 19 is rotated by the protrusion of the pin 18, and the spring 30
This is a storage means for the torque limiter 13 to prevent the lever 19 from returning to its original position by the urging force of the pin 18 and being rotated again by the pin 18 to repeatedly press the limit switch 21.

The rotary guide bush 15 of this embodiment has substantially the same structure as a general rotary guide bush. That is, the rotary guide bush 15 is fixed to the guide bush housing 22. The rotary guide bush 15 has a bearing 2 in the outer sleeve 23.
4, the gear 16 is fixed to this inner sleeve 25, and a tapered surface is formed at the inner diameter portion of the tip, into which a guide bush 26 is fitted and tightened with a nut 27. The guide bush is fixed, and the inner diameter of the guide bush is adjusted by tightening the nut 27.
A seal 28 is attached to the tip of the rotating guide bush 15.
is provided, cutting oil, chips, etc. are removed from the bearing 24.
This prevents them from entering the area.

In the automatic lathe of this embodiment, as in other headstock sliding type lathes, the driving force of the main shaft drive motor 1 is the first intermediate shaft 3.
It is transmitted to the main shaft 4 via the main shaft 4, and rotationally drives the workpiece gripped by the main shaft 4.

On the other hand, the headstock is sequentially advanced via the ball screw 9 by the rotation of the pulse motor 8. cutting tool 29
is attached to a tool post (not shown) and is located at the front mouth of the guide bush 26, and is cut into a desired shape by combining the forward movement of the headstock and the forward and backward movements of the cutting tool 29.

At this time, the rotational force of the rotating guide bushing 15 rotates the guide bushing 26 via the gears 10 and 12, the torque limiter 13, the second intermediate shaft 11, and the gears 14 and 16. If the reduction ratio from the first intermediate shaft 3 to the main shaft 4 and the reduction ratio to the guide bush 26 are made the same, the main shaft 3 and the guide bush 26 will rotate at the same rotational speed, and there will be a gap between the workpiece and the guide bush 26. No slipping occurs in the direction of rotation.

When cutting oil, fine chips, etc. enter the bearing 24 of the rotating guide bushing 15 and the bearing 24 malfunctions, the torque limiter 13 is activated with a predetermined torque and the limit switch 2 is activated via the lever 19.
1 to stop the machine urgently and prevent the bearing 24 of the rotating guide bush 15 from seizing, or even if the bearing 24 is not detected in time and the bearing 24 seizes, it will prevent the main shaft drive motor from burning out or other machine parts from being damaged. is completely prevented.

In the above explanation, the first intermediate shaft 3 and the second intermediate shaft 1
1 and 1, but as mentioned above, this is due to the tension of the timing belt 6 and the gear 1.
0, 12 and gears 14, 16, it is clear that by using other tensioning devices a single intermediate shaft is sufficient.

As detailed above, according to the present invention, it is possible to prevent the bearing from seizing due to poor rotation of the rotating guide bushing, or at least to completely prevent the drive motor from burning out or other parts from being damaged due to the bearing from seizing. , its practical effects are enormous.

[Brief explanation of the drawing]

FIG. 1 is a drive system diagram of an NC automatic lathe having a drive device for a rotary guide bush of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a cross-sectional view along AA of FIG. 2. 3...First intermediate shaft, 4...Main shaft, 5, 7...Timing pulley, 6...Timing belt, 1
0, 12...Gear, 11...Second intermediate shaft, 13...
...Torque limiter, 14, 16...Gear, 15
...Rotating guide bush.

Claims (1)

[Scope of utility model registration request] In an automatic lathe having a rotating guide bushing, there is a main shaft that grips and rotates a workpiece, an intermediate shaft that is provided parallel to the main shaft and rotates in synchronization with the main shaft, and a rotating guide bushing that is provided on the intermediate shaft and that rotates. an overload safety device that detects an overload caused by the overload and stops driving the entire machine; and an overload safety device that rotates concentrically and synchronously at the same rotation speed as the main shaft driven by the output shaft of the overload safety device. 1. A drive device for a rotary guide bush, comprising: a rotary guide bush.