JPH04256508A - Detecting method for cutting torque and device in drilling machine - Google Patents

Abstract

PURPOSE:To detect torque with simple structure by fixing plural permanent magnets on torque transmission flanges respectively fixed on the facing end parts of a driving shaft and a driven shaft and connecting the driving shaft and the driven shaft with magnetic force. CONSTITUTION:Torque transmission flanges 25, 24 are fixed respectively to the mutually facing end parts of the driven shaft 11 and the driving shaft 16 of a drilling machine. Plural permanent magnets 27, 26 are fixed on each of these flanges 25, 24, and transfer torque between the driving shaft 16 and the driven shaft 11 is changed by detecting each phase of these permanent magnets 26, 27 with magnetic sensors 31, 32.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting cutting torque applied to a drill when drilling a hole in a cutting material using a drill, and an apparatus for carrying out this method.

0002

[Prior art] When drilling holes using a drill,
When the drill has a small diameter or when drilling difficult-to-cut materials, a torque limiter function is installed on the part that connects the drive shaft and driven shaft, so that when the drive torque or thrust load exceeds a set value, the drive shaft and drill A drive shaft with a chuck that releases the connection, or when the drive torque or thrust load exceeds a set value, disconnects the connection between the drive shaft and the driven shaft, and at the same time moves the drive shaft back together with the driven shaft to stop it. Various devices have been proposed that emit alarms and alarms.

Conventional torque detection methods include a method of mechanically detecting the torsion of a torsion spring, a method of using a combination of a torsion bar and a strain gauge, and a method of using a combination of a torsion bar and a phase difference detection gear. .

0004

[Problems to be Solved by the Invention] The various conventional devices described above have the effect of preventing damage to the drill or workpiece or damage to the machine when an abnormality occurs during the drilling process, but they do not prevent drilling when an abnormality occurs. Since the machining is stopped, manual labor is required to restart the drilling work, and there is a problem in that the machine must be stopped.

[0005] In addition, in all of the above-mentioned known torque detection methods, it is difficult to detect extremely low torque acting on a shaft rotating at high speed with high accuracy, or it requires advanced technology. There's a problem.

An object of the present invention is to solve the above-mentioned problems by constantly detecting the cutting torque during drilling, and by performing drilling under optimal conditions for the detected value, thereby reducing manual labor. The object of the present invention is to provide a method for detecting torque that can safely perform drilling until the end without any need for drilling, and a method for detecting torque that can detect even extremely low torque with high precision.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a cutting resistance torque detection method for a drilling machine, in which a drive shaft driven by a drive means and a concentric shaft rotating together with a drill are provided. A large number of permanent magnets facing each other are fixed in a non-contact manner to torque transmission flanges fixed to opposite ends of the driven shaft, and the torque of the driving shaft is transmitted to the driven shaft through the magnetic coupling between the facing permanent magnets. A method for detecting cutting torque in a drilling machine, characterized in that the transmitted torque is determined by magnetically detecting the phase shift between the permanent magnet on the drive shaft side and the permanent magnet on the driven shaft side, and the method for drilling the hole. In a cutting resistance torque detection device for a processing machine, torque transmission flanges are fixed to opposing ends of a drive shaft driven by a drive means and a concentric driven shaft rotating together with the drill, and each torque transmission flange has a , a plurality of permanent magnets are arranged and fixed on a circumference concentric with the same diameter as the center of rotation so as to face each other at the same pitch, and both torque transmission flanges are connected by magnetic force, and furthermore, the phase of each torque transmission flange is fixed. The present invention provides a cutting torque detection device for a drilling machine, which is provided with magnetic sensors for detecting the deviation of the shaft, and has a circuit configured to convert the detected values of the magnetic sensors into torque transmitted between a driving shaft and a driven shaft.

[0008]

[Operation] Since the present invention has the above configuration, when the drive shaft starts rotating, there is no load on the driven shaft side, so the phase difference between the torque transmission flange on the drive shaft side and the torque transmission flange on the driven shaft side is There is almost no difference.

When the main shaft moves forward and the drill at the tip of the driven shaft cuts into the workpiece material, a phase shift occurs between the torque transmission flanges placed opposite each other depending on the cutting resistance, and this is detected by the magnetic sensor. be done. The detected values of each magnetic sensor are input to an arithmetic circuit and converted into transmitted torque. When the value of the transmitted torque exceeds a certain value due to the above action, the drill is prevented from becoming damaged by means such as retracting the main shaft.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIGS. 1 to 4 of the embodiment shown in the drawings, reference numeral 1 denotes a bed that supports the entire apparatus. A pair of parallel rails 2 are fixed on the left and right sides on this bed 1, and a slide base 4 is mounted on these rails 2 via linear motion bearings 3.
is attached so that it can move forward and backward.

A forward and backward feed screw 5 is mounted inside the bed 1 so as to be rotatable but not movable in the axial direction, and the shaft of a feed pulse motor 6 that drives the feed screw 5 is connected to the feed screw 5 by a coupling. be done.

Reference numeral 7 denotes an arm having a screw hole that engages with the feed screw 5 and is fixed to the rear lower end of the slide base 4. The slide base 4 is made by integrally joining a front member 9 and a rear member 10, and FIG. 3 shows the details thereof.

Reference numeral 11 denotes a driven shaft, which is rotatably but immovably mounted in the front member 9 via bearings 12 and 13, and the drill 1 is attached to a drill chuck 14 attached to the tip of the driven shaft.
Install 5.

Reference numeral 16 indicates bearings 19 and 2 in the rear member 10.
The driving shaft is rotatably mounted through the shaft 0 and cannot be moved in the axial direction, and is coaxial with the driven shaft 11, and has a pulley 17 fixed to the rear thereof.

A variable speed motor 23 is fixed to the front upper end of the bracket 22 fixed on the rear end of the rear member 10.
A pulley 21 is fixed to a shaft end that projects rearward from the rear end of a bracket 22. The pulleys 17 and 21 are interlocked by a belt 29, and the drive shaft 16 is rotated by a variable speed motor 23.

Torque transmission flanges 24 and 25 are fixed to opposing ends of the drive shaft 16 and driven shaft 11, respectively. The flanges 24 and 25 are opposed to each other with a slight gap X of about 0.2 mm as shown in FIG. 3, for example. The same number of permanent magnets 26 and 27 are embedded and fixed in the flanges 24 and 25 at regular intervals on a circumference that is concentric with the center of rotation and has the same diameter. These permanent magnets 26 and 27 have opposite poles that are the same, and both flanges 24 and 2
The driven shaft 11 is flush with the opposing surface of the driven shaft 11.
If the side is unloaded, each magnet 2 fixed to the flange 24
The flange 25 rotates with each magnet 27 located in the middle of the flange 25.

Magnetic sensors 31 and 32 are fixed to predetermined positions of the rear member 10 and front member 9, respectively, and permanent magnets 26 and 27 are exposed on the back surfaces of the respective flanges 24 and 25.
It is located close to the rear end of the.

33 in FIG. 4 is a control computer, and the detection signals from the magnetic sensors 31 and 32 are sent to the waveform shaping circuit 3.
4, the signal is input to the control computer 33 through the phase difference detection circuit 35 and the low-pass filter 36. Further, the feed pulse motor 6 is connected to a control computer 33 via a driver 37. In addition, there is an operation panel 39 for operating the drilling machine, and a C for various displays.
An RT 40 is equipped and connected to the control computer 33.

The control computer 33 also includes a CPU 41,
It is composed of a ROM and RAM 42, an A/D converter 43, a pulse motor controller 44, an I/O unit 45, a CRT controller 46, and the like.

The control circuit described above is similar to that described in ``Drilling Method and Apparatus'' currently filed as Japanese Patent Application No. 1-326811.

Next, the operation of the above control circuit will be explained as follows.
First, operate the keyboard on the operation panel 39 to determine the machining depth, retreat distance, cutting start gap, initial step distance, initial feed rate, maximum feed code, minimum feed code, feed variable amount at torque over and torque under. , the limit number of times when the torque is over, when the torque is under, when the thrust is over, the maximum cutting resistance torque value, etc. are input into the computer 33.
Make me remember.

When the initial value input operation is completed, the tip of the drill 15 is brought into light contact with the reference surface of the workpiece material (not shown) by manual operation, and the setting switch on the operation panel 39 is pressed. This causes the computer to memorize the reference position, and then the pulse motor 6 reverses the feed screw 5 to return the drill 15 to the rest position and stop it.

Next, when the start switch on the operation panel 39 is pressed, the pulse motor 6 and the variable speed motor 23 start rotating, and the feed screw 5 rotates forward at high speed to move the slide base 4.
is advanced in rapid traverse, and at the same time the drive shaft 16 starts rotating.

Then, the tip of the drill 15, which was in the rest position, approaches the reference surface of the workpiece in rapid traverse while rotating, and when the tip of the drill 15 is separated from the reference surface by the cutting start gap, the pulse motor 6 is turned on. The motor 6 stops once, then the motor 6 starts rotating at the cutting feed rate, and the drill 1
5 is advanced with cutting feed to cut into the workpiece and perform initial cutting.

In this initial cutting, the computer 33
When cutting is performed at the cutting feed rate and drill rotation speed set under the initial conditions stored in the computer 33, and the step distance that is also stored in the computer 33 is advanced, the pulse motor is activated to discharge chips generated during cutting. 6 reverses, the feed screw 5 is reversed and the drill 15 is retreated at high speed, and the drill 15 is retreated at a rapid rate until the tip of the drill 15 comes out of the reference plane.

Next, the pulse motor 6 starts rotating in the normal direction again, causing the feed screw 5 to rotate in the normal direction, and while rotating the drill 15, the drill 15 enters the previously drilled hole and starts from the inner end of this hole. After the tip of the drill 15 moves forward in rapid traverse until it reaches the position of the gap set by the conditions, cutting is started again.

During this cutting process, the cutting resistance torque is constantly monitored, and when it exceeds the maximum cutting resistance torque value set in the initial conditions, it is immediately retreated at high speed, and
The next cutting conditions are automatically corrected based on the values set in the initial conditions, and cutting is restarted.

In the above operation, when the drive shaft 16 is rotated and no load is applied to the driven shaft 11, the flanges 24 and 25 receive a repulsive force due to the repulsive force of the permanent magnets 26 and 27 attached to the flanges 24 and 25, as described above. The permanent magnets of the opposing flanges rotate together in a balanced position, that is, in a state where the permanent magnets of the opposing flanges are located between the adjacent permanent magnets 26 and 27 arranged on the circumference. Magnetic sensors 31 and 32 at this time
, the waveform shaping circuit 34, the phase difference detection circuit 35, and the low-pass filter 36 output signals are shown in FIG. 5a.

Furthermore, when a load is applied to the driven shaft 11 in this state, the positions of the permanent magnets 26 and 27 between the opposing flanges 24 and 25 of the driven shaft 11 are shifted from the no-load state position by an amount commensurate with the load. Rotate in the same position. The output signals from the magnetic sensors 31 and 32, the waveform shaping circuit 34, the phase difference detection circuit 35, and the low-pass filter 36 at this time are shown in FIG.
Shown below. That is, the output voltage from the filter 36 is a function of the torque transmitted between the drive shaft 16 and the driven shaft 11.

In the waveform diagrams of FIGS. 5a and 5b above, A1
, A2 is the output waveform from each sensor 31, 32, B1
, B2 is the output waveform from the waveform shaping circuit 34, C is the output waveform from the phase difference detection circuit 35, D is the output voltage from the low-pass filter 36, and in FIG. 5, a is when no load is applied, and b is when no load is applied. This is the case when becomes large.

The voltage (a function of the cutting torque value) output from the low-pass filter 36 and input to the control computer 33 is analyzed by a program stored in advance in the control computer 33 as described above.
Change machining conditions such as step distance and cutting feed rate to optimal values as needed. By doing so, the machining time is reduced, breakage of the drill is prevented, and the workability of the drilling process is improved.

[0032] In the embodiment, the permanent magnets 26 facing each other
, 27 are made to have the same polarity so that they are repelled, but they may be attracted by having different polarities facing each other.

[0033]

[Effect] As described above, this invention connects the driving shaft and the driven shaft by magnetic force by fixing a plurality of permanent magnets to the torque transmission flanges fixed to the opposing ends of the driving shaft and the driven shaft. , torque can be detected with a simpler structure compared to conventional methods that use springs, torsion bars, and strain gauges.

Furthermore, by setting the interval between the permanent magnets arranged on the circumference to a value commensurate with the transmitted torque, the phase difference between the driving side and the driven side of the torque transmitting flange with respect to the transmitted torque is expanded, and a minute position is It is easy to detect the phase difference, and since the torque is transmitted without contact, harmful vibrations on the driving side are absorbed and not transmitted to the driven side.

[Brief explanation of the drawing]

[Figure 1] Partial longitudinal side view of the embodiment

[Figure 2] Front view of the same as above

[Figure 3] Enlarged vertical cross-sectional view of the main parts of the same as above

[Figure 4] Block diagram same as above

[Figure 5] Output waveform diagram same as above

[Explanation of symbols]

11 Driven axis 14 Drill chuck 15 Drill 16 Drive shaft 24, 25 Torque transmission flange 26, 27 Permanent magnet 31, 32 Magnetic sensor 33 Computer

Claims (2)

[Claims] Claim 1: In a method for detecting cutting resistance torque of a drilling machine, a drive shaft driven by a drive means and a concentric driven shaft rotating together with a drill are fixed at opposing ends with a minute gap between them. A large number of permanent magnets facing each other are fixed to the torque transmission flange in a non-contact manner, and the torque of the drive shaft is transmitted to the driven shaft by the magnetic coupling between the facing permanent magnets. A method for detecting cutting torque in a drilling machine, characterized in that transmission torque is determined by magnetically detecting a misalignment between a permanent magnet on a driving shaft side and a permanent magnet on a driven shaft side. 2. In a cutting resistance torque detection device for a drilling machine, the torque is measured so that there is a minute gap between the opposing ends of a drive shaft driven by a drive means and a concentric driven shaft that rotates together with the drill. The transmission flanges are fixed, and a plurality of permanent magnets are arranged and fixed on the circumference of each torque transmission flange, which is concentric with the rotation center and has the same diameter, so as to face each other at the same pitch, and both torque transmission flanges are magnetically attached. Furthermore, a magnetic sensor is provided to detect the displacement of each of the torque transmission flanges that occurs in response to fluctuations in the transmission torque, and the detected value of each magnetic sensor is used as the transmission torque between the drive shaft and the driven shaft. A cutting torque detection device for a drilling machine, characterized by comprising a conversion circuit.