JPH0746443Y2 - Tool unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an improvement of a tool unit that uses a ball screw mechanism and a ball spline mechanism together.

2. Description of the Related Art As a tool unit in which a spindle equipped with a rotary tool such as a drill at its tip is reciprocally moved in the axial direction while rotating, the applicant has proposed a tool unit that uses both a ball screw mechanism and a ball spline mechanism. Proposed in No. 56381.

In the tool unit according to the above application, a ball screw groove and a ball spline groove that extends in the axial direction across the ball screw groove are provided on the outer peripheral surface of the main shaft, while a ball screw nut fitted to the main shaft is provided. First and second rotation driving means for individually rotating the ball spline nut are provided, and further control means for differentially controlling the first and second rotation driving means is provided, and the first and second rotation driving means are provided. When the ball screw nut is rotated by the rotary drive means, the main shaft reciprocates in the axial direction, while when the ball spline nut is rotated by the second rotary drive means, the main shaft performs the rotary motion. When the rotation driving means of (1) are simultaneously operated, the main shaft rotates and reciprocates in the axial direction. The rotation and the axial movement of the main shaft, that is, the axial feed is controlled by differentially controlling the rotations of the both nuts by the control means.

However, in the tool unit described above, the spindle feed of the spindle is controlled only by the rotation difference between the ball screw nut and the ball spline nut.
When the tool unit emergency stop due to
There is a possibility that the rotation difference between the both nuts increases and abnormal shaft feed is applied, the main shaft runs away, falls off from the nut, and the thread groove of the nut is damaged. In particular, when the spindle is rotating at high speed, runaway of the spindle is rapid and very dangerous.

The present invention has been made for the purpose of solving the above problems.

Means for Solving the Problems In order to achieve the above object, in the present invention, a clutch that operates in response to an operation of an emergency stop button of the tool unit is provided with a first rotation drive means and a second rotation drive means. If the reduction ratio is the same as that of the driving means, it is provided between them and the first and second rotation driving means are interlocked to eliminate the difference in rotation between the both nuts, or the clutch is used as a ball screw nut. It is provided between the nut for the ball spline and the nuts are interlocked with each other to eliminate the difference in rotation between the nuts.

Action According to the tool unit having the above configuration, when the emergency stop button of the tool unit is operated, in response to this, the clutch is actuated and the rotation difference between the both nuts is eliminated, so that even if the main spindle rotates. , Only the axis feed stops instantly.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a tool unit according to the present invention.
An attachment 11 for mounting a rotary tool (not shown) such as a drill is attached to the tip of 10. Further, the outer peripheral surface of the main shaft 10 is provided with a spiral ball screw groove 12 from the rear end to the substantially central portion, and a plurality of ball spline grooves 13 extending in the axial direction across the ball screw groove 12 are provided in the main shaft 10. It is provided from the rear end beyond the area where the ball screw groove 12 is formed. On the other hand, a spindle tip portion 10a protruding from a support frame 21 described later has a round shaft shape in which neither the ball screw groove 12 nor the ball spline groove 13 is processed.

A ball screw nut 15 and a ball spline nut 16 are fitted on the main shaft 10 through a large number of balls 14. A transmission pulley 17 is fixed to the end of the ball screw nut 15, and a transmission pulley 18 is fixed to the end of the ball spline nut 16.

Ball screw nut 15 fitted to the spindle 10 as described above
The ball spline nut 16 and
It is rotatably supported by a support frame 21 via 20. At this time, the tip end portion 10a of the main shaft 10 is projected to the outside through the tubular body 22 that is connected to the support frame 21,
A seal ring 23 is interposed between the outer peripheral surface of a and the end opening 22a of the tubular body 22.

On the other hand, the ball screw nut 15 includes a drive pulley 26, a timing belt 27, and a transmission pulley 17 fixedly mounted on a rotary shaft 25 of the first servomotor 24 attached to the support frame 21.
It is designed to be rotationally driven via. Further, the ball spline nut 16 includes a drive pulley 30, a timing belt 31, and a transmission pulley fixedly mounted on a rotation shaft 29 thereof by a second servo motor 28 also attached to the support frame 21.
It is designed to be rotationally driven via 18.

The reduction ratio between the first servomotor 24 and the ball screw nut 15 and the reduction ratio between the second servomotor 28 and the ball spline nut 16 are set to be the same. Reference numeral 32 is a control device for differentially controlling the first servo motor 24 and the second servo motor 28.

An electromagnetic clutch 33 is arranged between the drive pulleys 26 and 30, and an electromagnetic coil 34 thereof is fixed to the support frame 21. On the other hand, the clutch plates 35 and 36 facing each other can be fitted by spline-fitting a shaft 37 projecting from one clutch plate 35 to a cylindrical shaft 38 projecting from the other clutch plate 36 or by sliding through a key. And is urged by a spring 39 so as to be separated from each other, and a cylindrical shaft 38 is rotatably supported in the electromagnetic coil 34 via a bearing 40.

As shown in FIG. 2, the electromagnetic coil 34 is connected to the electric circuit of the emergency stop button 41 of the tool unit, and when the operator operates the emergency stop button 41, the current is cut off. ing. Therefore, the current always flows through the electromagnetic coil 34, the clutch plates 35 and 36 are made to approach each other against the spring 39, and the non-operating state (neutral state) is maintained, but the emergency stop button 41 is operated. When the current to the electromagnetic coil 34 is cut off, the clutch plates 35 and 36 are separated from each other by the spring 39, the clutch plate 35 contacts the drive pulley 26, and the clutch plate 36 contacts the drive pulley 30. 26 and 30 are interlockingly connected via clutch plates 35 and 36.

The tool unit having the above configuration, when the ball screw nut 15 is rotationally driven, the spindle 10 reciprocates in the axial direction,
When the ball spline nut 16 is driven to rotate, the spindle 10
Makes a rotational movement. Therefore, when both nuts 15 and 16 are driven to rotate at the same time, the spindle 10 reciprocates in the axial direction while rotating, so drilling with a drill, tap or other rotary tool (not shown) attached to the tip of the spindle 10 ,
Performs tapping.

However, when the main shaft 10, which is also a ball screw shaft, is rotated with respect to the ball screw nut 15, the main shaft 10 itself moves in the axial direction due to the screw action, so when the main shaft 10 rotates, the first servomotor 24 and the second servo motor 24 The servomotor 26 is always operated, and the control device 32 differentially controls the rotations of both nuts 15 and 16 so as to maintain a constant rotation difference. Set it arbitrarily. In this case, since both nuts 15 and 16 are constantly rotating, the shaft feed speed can be adjusted easily and quickly.

Further, since the ball screw groove 12 and the ball spline groove 13 are not provided in the tip portion 10a of the main shaft 10 which is the operation part of the rotary tool, and the outer peripheral surface is sealed by the seal ring 23, both nuts 15 It is possible to effectively prevent dust and other foreign matter from entering the 16 ,. Meanwhile, the ball screw groove 12
Also, since the shaft portion provided with the ball spline groove 13 is not exposed to the front by the seal ring 23, there is no inconvenience that grease or lubricating oil applied to the shaft portion is scattered.

Then, when the worker actuates the emergency stop button 41 due to a power outage or an abnormality in the NC during working with the above-mentioned tool unit, the current of the electromagnetic coil 34 is cut off, so that both clutch plates 35, 36 are The springs 39 push the clutch plates 35 against each other so that the clutch plates 35 contact the drive pulley 26,
The clutch plate 36 comes into contact with the drive pulley 30 and both drive pulleys 2
6, 30 are interlockingly connected via both clutch plates 35, 36. Due to the interlocking connection of both drive pulleys 26 and 30, the rotary shaft 25 and the rotary shaft 29 rotate synchronously, and further, the nuts 15 and 16 with the same reduction ratio from both drive pulleys 26 and 30 also rotate synchronously and the rotation difference between them. Since there is no longer, the spindle feed of the spindle 10 stops. At this time, the electric currents to the first and second servomotors 24 and 28 are also cut off, but the rotating shafts 25 and 29 thereof continue to rotate due to the inertial force, so that the main shaft is inserted via the ball spline nut 16.
Although 10 spins, axis feed stops immediately.

FIG. 3 shows a tool unit in which the electromagnetic clutch 33 is provided between the ball screw nut 15 and the ball spline nut 16 so that both nuts 15 and 16 are directly interlocked and synchronously rotated during an emergency stop. Shows.

In this tool unit, clutch plates 35 and 36 are axially slidably mounted on the ends of nuts 15 and 16, respectively, and are biased by springs 42 to abut each other. On the other hand, the electromagnetic coil 34 disposed between the two clutch plates 35 and 36 is excited by the electromagnetic coil 34 and the two clutch plates 3
It acts to space 5,36 against spring 42.

Therefore, when the operator actuates the emergency stop button 41 to cut off the current of the electromagnetic coil 34, the clutch plates 35 and 36 come into contact with each other by the action of the spring 42, and the nuts 15 and 16 are fixed to the clutch plate 3 respectively.
Since they are linked together via 5,36 and rotate synchronously, the spindle 10
Axis feed stops.

Effect of the Invention As described above, the tool unit of the present invention uses the clutch that operates in response to the operation of the emergency stop button to rotate the ball screw nut and the ball spline nut in synchronism so that the nut Since it is configured to eliminate the difference in rotation, it is possible to instantaneously stop only the shaft feed without stopping the rotation of the main shaft.

Therefore, when the tool unit is brought to an emergency stop due to a power failure, NC abnormality, etc., it is possible to reliably prevent runaway of the spindle, resulting in extremely high safety.

In addition, the entire device can be made compact, and a highly accurate and highly safe uniaxial tool unit can be obtained.

In addition, by differentially controlling the ball screw nut and the ball spline nut, the feed speed of the spindle can be adjusted easily and quickly, so the response is superior to that of the conventional device with a separate rotation mechanism and feed mechanism. There is.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view of a tool unit according to the present invention, and FIG.
FIG. 3 is an electric circuit diagram of the clutch, and FIG. 3 is a vertical sectional front view showing another embodiment. 10 …… Spindle, 11 …… Attachment 12 …… Ball screw groove 13 …… Ball spline groove, 14 …… Ball 15 …… Ball screw nut 16 …… Ball spline nut 17,18 …… Transmission pulley, 21… … Support frame 24 …… 1st servo motor 28 …… 2nd servo motor, 32 …… Control device 33 …… Electromagnetic clutch, 34 …… Electromagnetic coil 35, 36 …… Clutch plate 41 …… Emergency stop button

Claims (2)

[Scope of utility model registration request] 1. A ball screw groove and a ball spline groove extending in the axial direction across the ball screw groove are provided on the outer peripheral surface of a main shaft on which a rotary tool such as a drill is mounted, and are fitted to the main shaft. First and second rotation driving means for individually rotating the ball screw nut and the ball spline nut are provided, and further control means for differentially controlling the first and second rotation driving means is provided. In the tool unit, the clutch that operates in response to the operation of the emergency stop button of the tool unit is provided between the first rotation driving means and the second rotation driving means having the same reduction ratio. Characteristic tool unit. 2. A clutch, which operates in response to an operation of an emergency stop button of the tool unit, is provided between the ball screw nut and the ball spline nut. Tool unit.