JPH01301018A - Torque detector for tapping machine - Google Patents

Abstract

PURPOSE:To improve load torque detection accuracy by fixing a pair of encoders vertically through an elastic member then detecting the overlapping range of alits within the range of respecetive central angles 2theta and calculating the value of load torque. CONSTITUTION:Rotary force of a belt 12 is transmitted through a belt wheel 9, a spindle sleeve 7, an elastic member 13 and a spindle fitting member 15 to a spindle 2. First and second encoders 16, 17 are fixed respectively to the spindle pulley 7 and the spindle fitting member 15 with the elastic member 13 being held between them, where slits X, X'; and Y, Y' having central angle of 2theta are made respectively with phase shaft of theta. Overlapping degree of the slits X and Y, X' and Y' is detected through an optical detector 19, and when the elastic member 13 rotary deforms due to the load torque applied onto a tap the overlapping degree of the slit varies to vary the width of pulse outputted from the optical detector 19 thus enabling calculation of the value of load torque. By such arrangement, load torque can be detected accurately for both right hand and left hand screw tap.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides a tapping device that immediately detects when an overload is applied to a screw tap attached to a tapping drilling machine and prevents the screw tap from breaking. This invention relates to a torque detection device for a drilling machine.

[Background of the invention]

When tapping using a tapping drilling machine,
If the blade of the screw tap is worn, the diameter of the pilot hole pre-drilled in the workpiece material is small, or the tapping speed is too fast, the torsional torque generated in the screw tap will increase, causing the screw tap to If the maximum allowable torque value is exceeded, the screw tap will break.

As a means for protecting the screw taps of a tapping drilling machine from breakage, Jitto No. 58-137177 has been proposed. An overview of Utility Application No. 137177/1983 will be explained using FIGS. 1 and 9. Spindle sleeve 7 and main shaft 2
are integrally attached via an elastic body 13, and a first encoder 16 and a second encoder 17 shown in FIG. 9 each having a slit are attached to both the spindle sleeve 7 and the main shaft 2. The same number of perforations X (X□, At the same radius position as each drilling hole X and at a relative arrangement angle of 0 (01,0□
,...) in the positive and negative directions respectively (Y□
, Y2. ) and further each encoder 16.
Drill holes symmetrically with respect to the center point of 17 (X□, X2...
and Yl, y2. ...) and the perforations X (Xl, X2..) formed in the first encoder 16.
), the number of photodetectors 19 (19a
, 19b, ...), select the photodetector 19 according to the tap size, and select the photodetector 19 according to the tap size. By overlapping the perforations of each encoder 16, 17, the photodetector 19 is configured to detect an abnormality.

However, according to this structure, the number of types of taps used is n
In this case, the first encoder 16 requires an integral multiple of r1 holes, and the second encoder 17 requires 2n holes.
Since the number of holes Y is an integer multiple of n, additional n photodetectors 1 are required.
9 is required.

Therefore, there are limits to the number of perforations and the number of photodetectors 19 that can be formed in the same encoder due to constraints on the arrangement space and price.

Depending on the thread diameter, thread pitch, and material of the workpiece, the number of types of screw taps varies depending on the application, such as mild steel, 1g iron, aluminum, etc., including general shapes, spiral shapes, gun tap shapes, etc. becomes very large.

As described above, it is not possible to detect the allowable maximum torque value of each of the various types of screw taps using the conventional method.

Furthermore, if the elastic body 13 undergoes some degree of permanent torsional deformation due to aging, there is no mechanism for correcting this torsional deformation, so it is not possible to accurately detect the load torque applied to the screw tap during the tapping process. Furthermore, there was a problem in that the error in detecting the load torque increased during right-handed rotation drive, left-handed rotation drive, and middle rotation. Therefore, when there is only one photodetector, the perforations formed in the first encoder and the second encoder are f
With fσ delivery, it is possible to accurately detect the load torque applied to the screw tap during both clockwise and counterclockwise rotation, and to detect excessive loads depending on the various screw tap sizes and types and the material of the workpiece. There has been a need for a device that detects the occurrence of torque and prevents breakage of screw taps.

[Object 1 of the Invention] The object of the present invention is to eliminate the drawbacks of the prior art described above, detect the occurrence of excessive load torque applied to the tap, and provide a method that corresponds to the maximum allowable torque value of each of various types of threaded taps.
The tapping drilling machine is equipped with a highly reliable torque detection device.

[Summary of the invention]

According to the present invention, a spindle sleeve and a main shaft of a cutting drilling machine are integrally attached via an elastic body, and first and second encoders attached to both the spindle sleeve and the main shaft are centered at the same radius in the circumferential direction. Angle 2D @
A surrounding slit is formed, and a relative positional relationship is maintained so that the slits overlap within a center angle of 0, and the overlap of the slits of both encoders is detected by a photodetector. The pulse period time to and pulse time width Lx of the detection signal from the photodetector during processing are ap+
If the torsion angle P of the elastic body is calculated, the load torque value T applied to the screw tap can be calculated even during clockwise and counterclockwise rotation.
can be detected accurately.

measuring the time of the detection signal output from the photodetector;
The torsion angle P of the elastic body is calculated by calculation, and the load torque value T applied to the tap is calculated, and the allowable maximum torque value determined corresponding to the load torque value T and each screw tap size and type inputted externally in advance is calculated. is set in a storage device, and an arithmetic processing device is provided which compares the load torque value T with the maximum allowable torque value of the screw tap specified by an external input device. Also, the maximum usable rotational speed is set in advance in the memory device according to the screw tap size to be used and the material of the workpiece.

A warning device is provided that issues an nJ alarm if an attempt is made to tap the screw at a rotation speed higher than that.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 8.

In Fig. 1, 1 is the head of a tapping drilling machine, 2
numeral 3 is a main shaft with a spline shaft portion on the upper side; 3 is a cryle supporting the main shaft 2; a support 4 is provided on the outer periphery of the cryle 3; 5 is a pinion engaged with the rack 4; 6 is a pinion shaft; when the pinion shaft 6 is rotated by a handle (not shown), the main shaft 2 slides in the vertical direction via the cryle 3; 7 is the spindle sleeve, 8 is the bearing of the spindle sleeve 7,
is supported by the head 1 via a bearing 8. 9
is a bell 1-wheel, and the bell 1-wheel 9 is integrally attached to the spindle sleeve 7 via a key 10 and a nut 11, and the belt pulley 9 is connected to an electric motor (not shown) via a belt 12. ) is transmitted. An elastic body 13 is attached to the lower end of the spindle sleeve 7 via a screw 14, and the torsion angle changes depending on the amount of torque when a load torque in the rotational direction is generated on the main shaft 2. Reference numeral 15 designates a main shaft insertion member. The main shaft insertion member 15 has a spline hole in its inner diameter portion and engages with the spline shaft portion of the main shaft 2 described above. It is integrally attached to the elastic body 13. That is,
The rotational force from the electric motor is applied to the belt 12 and the belt wheel 9.
．． Spindle sleeve 7, elastic body 13, main shaft insertion member 1
5 to the main shaft 2. spindle sleeve 7
A first encoder 16 having a slit having a central angle of 20 as indicated by X in FIG. Further, a second encoder 17 having a sulin 1 with a center angle 2θ shown as Y in FIG. 19 is a photodetector, and as shown in FIG.
It is fixed to the head 1 via a holding member 20 so as to be in a position where it can pass through the slit provided in the head 7 .

○-X of the encoder 16 shown in FIG. 2(a).

The encoder 17 is attached via the elastic body 13 as shown in the principle diagram shown in FIG. 2(C) while maintaining a relative positional relationship such that the encoder 17 coincides with o-y2 of the encoder 17 shown in FIG. 2(B). When the elastic body 13 is not twisted, the center angle O range of Xo-〇-X□ of the slit X formed in the encoder 16 and Y2-0 of the slit Y formed in the encoder 17
The range of the central angle O of -YO will be polymerized.

(1) When the screw tap is being driven to the right (when the right-hand screw tap is being used), when a load is applied to the screw tap, the first elastic body 13 is twisted according to the load, and the overlapping range of the slits formed in the encoder 16 and 17 is As shown in the figure (a), the center angle is 0 (Y2-
The center angle 0R (Yo-〇-X) is larger than 〇-Yo).

(2) When a load is applied to the screw tap during left-handed rotation drive (while using a left-handed screw tap), the elastic body 13 is twisted in accordance with the load, and the overlapping range of the slits formed in the encoder 16 and 17 is As shown in the figure (b), the center angle is 0 (Y2
-0-Y, ) is smaller by the central angle 0L(y, -o-x,).

Therefore, by detecting these central angles OR and θm, the torsion angle P of the elastic body 13 can be found as P=θR1 or P=Ot, and from the torsional spring constant K of the elastic body 13, right-handed tap and left-handed tap are determined. No matter which one is used, the load torque value '■' applied to the screw tap is 'r=K ・O
It can be calculated as n, T=K·Ob.

In this mechanism, since the maximum measurement of the torsion angle P of the elastic body 13 is 0, it is equivalent to the allowable maximum torque value TMrnax of the largest screw tap among the screw tap sizes and types that can be installed on the tapping drilling machine. Elastic body 1
A slit with a center angle of 20 is formed in the encoders 16 and 17 to convey torque detection during clockwise and counterclockwise rotation. It is something.

Next, the torsion angle P of the elastic body 13, that is, the center angle Or
Detection of e, 0m will be explained.

(1) Consider the case of right-handed rotation driving (right-handed screw tap in use).

First, since the torsion angle P of the elastic body 13 is zero during no-load rotation, the ring hX formed on the encoder 16.
, Y have a central angle O, and when detected by the photodetector 19, the encoder 1G is detected as shown at 21 in FIG.
, 17 rotate once, a detection signal of logic "1" with a pulse time width tx=tqo corresponding to the overlapping range of the slits °X, Y is generated at intervals of the pulse period time to. From the ratio of this pulse time 'I'llll t no o and pulse period time to, if the polymerization angle of Surin hX and Y is O'u, then D'p = 2πXtao/jo. becomes equal to O.

When a load is applied to the screw tap during the tapping process, as shown in Figure 4 (a) and c, the pulse time width Lx at which the detection confidence of the photodetector 19 becomes logic ``1'' becomes, □ +jR□ increases. Therefore, the torsional angle P occurring in the elastic body 13
Let PR□, P, 2□ respectively, PR1==2πXtR
□/1o-0', PR, = 2gX702/lO-θ
′, and the load applied to the screw tap 1−
The torque value T is T, 1. If TFL□, then TRx =
It can be calculated as K x PRl + TR2=K x PR2.

(2) Consider the case of left-handed rotation drive (while using a left-handed screw tap).

Figure 4 (b) during no-load rotation, as well as during clockwise rotation 1 rotation.
As shown in (a), during one rotation of the encoder 16.17, the logic rlJ is detected (the fi number is at the interval of the pulse period time to From the ratio of the generated pulse time width tLo and the pulse period time to, if the overlapping angle of the slits X and Y is O''mu, then 0'mu = 2πXtLo/lo, this value is equal to the center angle O mentioned above. Become.

When a load is applied to the screw tap during the tapping process, the pulse time width tx = tLo at which the detection signal of the photodetector 19 becomes logic "1" becomes b tL as shown in Fig. 4 (b) and c.
-11tLJ2. Therefore, the torsion angles P occurring in the elastic body 13 are P and L, respectively.

If PL2, Pl-1=2 πX tL, l/t
o O't-Hp,, = 2 x X uL, /
It can be calculated by dividing t o -0't, and if the load torque value T applied to the screw tap is 'f゛, □, T, respectively, then TL□=KXPL, yo, TL 2= KXPX
M can be calculated.

As described above, even during clockwise and counterclockwise rotation driving, the photodetector 19 detects the overlapping range of Surin l-X and Y formed on the encoder 16 and 17, and the logic of the detection signal is "1".
The pulse period time 1; o and the pulse time width t,
The torsion angle P occurring in the nine-point elastic body 13, which determines x by Δ1g, is determined, and the load 1 to torque value T applied to the screw tap can be easily calculated.

Furthermore, according to this detection means, even if the elastic body 13 undergoes some degree of permanent torsional deformation due to aging, the pulse time width of the detection signal during no-load rotation (both clockwise and counterclockwise rotation) is maintained. It'll be determined that Lx and the pulse period time to are set, and as described above, <OL, O'a are set to L'', and even if these values are not equal to θ, based on these θ'1., θ'g, In order to calculate the torsion angle P of the elastic body 13 by measuring the pulse period time to and pulse time Illtx of the detection signal during the tapping process, the permanent torsion deformation ΔP=O'u-
0 or ΔP=0'mu θ can be corrected to obtain an accurate load torque value T.

Next, the operation of the arithmetic processing device will be explained using FIGS. 5 to 8. Fig. 5 is a block circuit diagram, in which a detection signal obtained by detecting the overlapping range of Surin +-x, y formed on the encoder 16. Various conditions such as tap size and type, as well as the material of the workpiece, etc., are determined by the microcomputer 2.
2 is entered. These input signals are read and the microcomputer 22 operates the right rotation relay 23 and the left rotation relay 24 to drive the electric motor (not shown) to the right or left as appropriate, thereby driving the main shaft 2 to the left (right or left). (when using a threaded tap) and left-handed rotation drive (when using a left-handed threaded tap).

The 9 notification device 25 receives input from the external input device 21. 1
Under these conditions, calculate the maximum allowable rotational speed Nmax, which the screw tap can use, measure the pulse cycle time of the detection signal of the photodetector 19 during no-load rotation, and find the actual rotational speed, Nmax, <When H, microcomputer 2
According to instructions from 2, old news will be issued.

FIG. 7 shows data necessary for the microcomputer 22 to execute arithmetic processing based on various conditions of the photodetector 19 and the external input device 21.

Fig. 7 (a) Maximum usable rotational speed Nmax depending on the combination of screw tap size and workpiece material
, are predetermined as N□ to N6, and the microcomputer 22
This is what is set in the memory 'Jan'. Figure 7 (
b) depends on the screw tap size and type of screw tap.
Each allowable maximum torque value 'r''Mmax is predetermined as shown in the table and set in the storage device within the microcomputer 22.

FIG. 8 is a flowchart 1 showing an explanation of the operation of the present invention.

For example, if the thread tap diameter used is [right-hand thread], [general thread],
[6 mm], and the workpiece material is [aluminum]. First, when these input conditions are inputted from the external input device 21, they are read by the microcomputer 22, and from Fig. 7 (a), the maximum rotational speed to be used is Nmax, = N, and from Fig. 7 (b), the allowable maximum rotational speed is 1 to Set TMmax,=”r,−0.

Next, measure the pulse period time to and pulse time width tx of the detection signal during no-load rotation, and create a RAM (random access memory) area [θ] to store the calculated value O'u = 2πXLx/lo. Clear it. External input device 2
1, the clockwise rotation relay 23 is energized and the main shaft 2 is rotated clockwise. After that, a rising change of the detection signal of the photodetector 19 from logic rQJ to "1" is detected, and a timer counting operation of pulse period time to is started, until the detection signal changes from logic "OJ to rlJ" again. Continue the timer counting operation. (This timer counting operation is necessary for operating the microcomputer 22, and is performed at a timing that is an integral multiple of the clock cycle of the lock signal.) This measured pulse cycle time t , from o to no-load rotation speed N=60/lo
is calculated, and if N)Nmax,=N, the alarm device 25 is activated. If N≦Nmax, = N, then the pulse time 1 for which the detection signal is logic “1”
Count u L X with a timer. Here, if no value is stored in [0] of the RAM area, 0'q = 2πX
Calculate tx/lo and store the value in [0] of the RAM area.

Next, the pulse cycle time to of the detection signal during tapping
The measurement of , pulse time width t, and x is repeated, and each time the torsion angle P occurring in the elastic body 13 and the load torque value T applied to the screw tap are calculated from the following formula.

P = 27CX t x / t o -0'T=K
XP Compare the calculated load torque value T and the above-mentioned allowable maximum torque value with T'Mmax, = T6-1, and T≦
If TMmax,=TG-8, the measurement of the pulse period time to and pulse time @tx of the detection signal is repeated.

If T)TMmax, =T, -□, the load torque value applied to the screw tap exceeds its allowable maximum torque value, and excessive load torque is generated, so immediately The computer 22 deenergizes the clockwise rotation relay 23 to stop the clockwise rotation of the main shaft 2. After that, a slight delay time is provided, and the counterclockwise rotation relay 24
is energized, the main shaft 2 is immediately rotated counterclockwise, and the threaded tap, which is experiencing excessive load torque, is separated from the workpiece. Thereafter, in response to an input instruction from the external input 1, the counterclockwise rotation relay 24 is deenergized to stop the rotation of the main shaft 2.

According to 29, even if an excessive load of 1-lux is applied to the thread tap during the tapping process, breakage of the thread tap can be prevented.

In addition to the above-described example, the maximum rotational speed Nmax, allowable maximum torque value TMmax, of the screw tap to be used can be determined by the microcomputer 22 according to various conditions inputted by the external input device 21, as shown in FIG. By selecting the setting values shown in (a) and (b), the rotational speed N of the screw tap and the load 1 - torque value T can be detected in the same manner as described above.

Furthermore, in the above description, as shown in FIGS. 2(a) and 2(b), the encoders 16 and 17 are connected to Surin 1-X.

In the case of forming Y, in FIGS. 2(a) and 2(b), slits X′Y l are additionally formed symmetrically with respect to the center point of each encoder 16, 17. According to the present invention, torque detection can be performed multiple times during one rotation of the main shaft 2, and the accuracy of torque detection can be improved. A range slit with a center angle of 20 is formed in the same radius and circumferential direction on the integrated encoders located above and below, and the mutual slits are overlapped with each other with a center angle of 0, and the overlapping range of the slits of both encoders is illuminated. Detected by a detector, Jiff-determined the pulse period time to and pulse time width LX of the detection signal, and determined the torsion angle P of the elastic body from the ratio of the increase/decrease in the pulse time width tx and the pulse period time to; An arithmetic processing device is provided which calculates the load torque value 'r applied to the screw tap during tapping by multiplying by the torsional spring constant I (of the elastic body).

Even if some permanent torsional deformation occurs in the elastic body, the load torque value T can be calculated by correcting it, and the accuracy of load torque blowout can be improved in both right-handed and left-handed threaded taps. In addition, by inputting various score conditions such as size, type, material of workpiece material, etc. from an external input device, the maximum rotational speed Nmax of the screw tap to be used, the maximum allowable rotation speed, etc. The torque value TMmax is selected from the values stored in advance in the storage device, and compared with the actual no-load rotation speed N and the load 1 - torque value T applied to the screw tap during tapping, and N > N is determined. max
, the alarm system will be activated when .

When '11''> T M max , the rotation of the main shaft is stopped and then reversed, so that breakage of the screw tap can be prevented.

4. Brief explanation of the drawings Fig. 1 is a vertical cross-sectional view of the main parts of a tapping drilling machine incorporating the torque detection device of the present invention, Figs. 2 and 3 are diagrams of the principle of the device of the present invention, and Fig. 4 is a timing chart, Fig. 5 is a block circuit diagram, Fig. 6 is a front view of the external input device, Fig. 7 is memory data, Fig. 8 is a flowchart 1 diagram, and Fig. 9 is a diagram of the principle of the conventional technology. It shows. .

In the figure, 2 is the main shaft, 7 is the spindle sleeve, 13
15 is an elastic body, 15 is a main shaft insertion member, 16 and 17 are encoders, 19 is a photodetector, 21 is an external input device, 22 is a microcomputer, 23 is a relay for forward rotation, 24 is a relay for reverse rotation, and 25 is an alarm device. It is.

Name of patent applicant: Co., Ltd. [1 Riko 1. fl fil
Town Sai 1m Sai ZrfU (〕】
(ri) (ha) Y+ 3 (!l (i)
(mouth 2 end 40 (a) Hirisai 5 cause 6c 2X and +7 (¥1 sai g mouth sai de diagram)

Claims (1)

[Claims] 1. An elastic body is provided on the outer periphery of the lower end of the spindle sleeve which is supported by the head and is rotationally driven, and a screw tap is rotatably driven through the elastic body, and a screw tap is rotatably driven through the elastic body. A photodetector is provided near the first encoder and the second encoder provided below, and when torsional torque is generated in the elastic body, the photodetector detects the overlap of the slits formed in both the encoders. In the tapping drilling machine that senses an overload condition applied to a screw tap, a slit is formed in the first and second encoders with the same radius and within a range of center angle 2θ in the circumferential direction, and The first encoder and the second encoder are mounted above and below the elastic body while maintaining a relative positional relationship such that the slits formed in the encoder overlap within a range of center angle θ, and the slits of both encoders and the second encoder are mounted above and below the elastic body. One photodetector is arranged at the same radius position, and the photodetector detects the overlapping range of the slits of both encoders during rotational driving, and the pulse synchronization time to and pulse time width tx of the detection signal are is measured, and from the times to and tx, the torsion angle P occurring in the elastic body is calculated, and the load torque value T applied to the screw tap is calculated. It has an arithmetic processing unit for comparing the magnitude with the allowable maximum torque value TMi determined corresponding to the screw tap size and type inputted by the screw tap, and detects excessive load torque applied to the screw tap during tapping process. A torque detection device for a tapping drilling machine. 2. The slits formed in the first and second encoders have a maximum allowable torque value TMmax. The torsion angle P of the elastic body corresponding to Pmax. If the Pmax. and the center angle 2θ of the slit formed in the first and second encoders, 2Pmax. The torque detection device for a tapping drilling machine according to claim 1, which has a relationship of <2θ. 3. In measuring the time of the pulse of the detection signal from the photodetector, measure the pulse synchronization time to and pulse time width tx during no-load rotational driving, and calculate the torsion angle ΔP of the elastic body at no-load. However, if a slight twist angle has occurred, the invention has an arithmetic processing device that can correct the twist angle ΔP and calculate the twist angle P of the elastic body during the tapping process. A torque detection device for a tapping drilling machine according to item 1 or 2. 4. When calculating the torsion angle of the elastic body, use the increase difference in the pulse time width tx and the pulse period time to during clockwise rotation drive (when using a right-handed screw tap), and use the pulse period time to during counterclockwise rotation drive (when using a right-handed screw tap). (when using a left-handed screw tap), one item selected from claims 1 to 3, comprising an arithmetic processing device that calculates using the decrease difference in the pulse time width tx and the pulse period time to. Torque detection device for a tapping drilling machine described in . 5. The slit of the first encoder and the slit of the second encoder are formed symmetrically with respect to the center point of each encoder, so that torque detection can be performed multiple times during one rotation of the encoder. A torque detection device for a tapping drilling machine according to one of claims 1 to 4. 6. Screw tap size and type from the external input device;
Furthermore, it is possible to input the material of the workpiece, and based on these input conditions, the maximum usable rotational speed is stored in advance in the storage device, and the pulse period time to is determined from the detection signal from the photodetector during no-load rotational driving. Claim 1: The invention comprises an arithmetic processing device that measures the rotational speed, calculates the rotational speed, and determines whether the rotational speed exceeds the maximum usable rotational speed, and, if necessary, an alarm device that issues an alarm. The torque detection device for a tapping drilling machine according to one item selected from items 1 to 5.