JPS6310908Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of application of the invention] The invention detects immediately when an overload is applied to a screw tap attached to a tapping board, and prevents the screw tap from breaking. This invention relates to a torque detection device for a tapping board.

[Background of the idea]

When tapping a screw using a tapping machine, if the blade of the screw tap is worn or the diameter of the pilot hole pre-drilled in the workpiece material is small, the torsional stress generated in the screw tap becomes large. If the value exceeds a certain value, the screw tap will break.

Conventionally, a friction clutch is generally used as a means to protect the screw tap of a tapping machine from breakage, and when a predetermined torque is applied to the screw tap during tapping, the clutch portion of the friction clutch slips. This prevents rotational force from being transmitted to the screw tap. The friction clutch has a simple structure and can be manufactured at a relatively low cost, but on the other hand, it is troublesome to have to adjust the frictional force of the clutch portion every time the diameter of the screw tap used changes. Moreover, the adjustment of the frictional force is
The current situation is that it is not possible to obtain the optimum condition with a single adjustment, but it is actually necessary to tap several times to obtain the appropriate frictional force.

On the other hand, Japanese Patent Publication No. 54-15354 has been proposed as a means to protect the blades of cutting machines from breakage. The outline of Japanese Patent Publication No. 54-15354 is to use electromagnetic force to control the resistance torque of the cutter, but according to this structure, the electromagnetic coil must also move with the spindle during drilling. It is possible that it is difficult to dispose of the electric wires that connect to the electromagnetic coil. Moreover, the special public service 54-15354
Since this method uses magnetic force to control the torque of the cutter, consideration must be given to the possibility that floating iron powder and belt rubber friction powder generated by friction between the cart and the belt may adhere to the excitation part during drilling. There must be.

[Purpose of invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, to optically detect tap overload, to provide a torque detection device with a simple structure and high reliability, and to provide a tapping board with good operability. This is what we are trying to provide.

[Summary of the invention] The present invention involves attaching a chuck to the rotating main shaft, attaching a screw tap to the chuck, transmitting the rotational power of the electric motor to the V-belt wheel via the belt, and transmitting the rotational power transmitted to the V-belt wheel. In the structure of a tapping machine that transmits power to a spindle sleeve and further transmits the rotational power transmitted to the spindle sleeve to a main shaft to perform thread tapping, the spindle sleeve and the main shaft are integrally attached via an elastic body. , and a first encoder and a second encoder each having a slit are attached to both the spindle sleeve and the main shaft, and the first encoder has the same number of slits as the number of types of tap sizes on a straight line in the radial direction. The second encoder has slits at the same radius as the slits in the first encoder, but with different relative arrangement angles in the positive and negative directions, and the center of each encoder. forming slits symmetrically with respect to the point, and disposing the same number of photodetectors as the number of slits near the slits formed in the first encoder, selecting the photodetectors according to the tap size, During the tapping process,
The apparatus is characterized in that the slits of each encoder are overlapped when a twist corresponding to the maximum permissible torque amount of the tap in use occurs in the elastic body, thereby detecting an abnormality with a photodetector. be.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

In Figure 1, 1 is the head of the tapping board;
Reference numeral 2 indicates a main shaft having a spline shaft portion on the upper side, 3 indicates a quill supporting the main shaft 2, and a rack 4 is provided on the outer periphery of the quill 3. 5 is a pinion engaged with rack 4, 6 is a pinion shaft,
When the pinion shaft 6 is rotated by a handle (not shown), the main shaft 2 reciprocates up and down via the quill 3. 7 is a spindle sleeve, 8 is a bearing of the spindle sleeve 7, and the spindle sleeve 7 is supported by the head 1 via the bearing 8. Reference numeral 9 denotes a V-belt wheel. The V-belt wheel 9 is integrally attached to the spindle sleeve 7 via a key 10 and a nut 11. A motor (not shown) is connected to the V-belt wheel 9 via a belt 12.
The rotational power from 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 according to the amount of torsion torque 7 generated on the main shaft 2. 15 is a main shaft insertion member;
has a spline hole in its inner diameter portion and engages with the spline shaft portion of the main shaft 2 described above, and the main shaft insertion member 15 is integrally attached to the elastic body 13. That is, the rotational power from the electric motor is
It is transmitted to the main shaft 2 via the belt 12, the V-belt pulley 9, the spindle sleeve 7, the elastic body 13, and the main shaft insertion member 15. An encoder 16 having a slit indicated by X in FIG. 2A is fixed to the spindle sleeve 7 by means such as press fitting. The main shaft insertion member 15 also has an encoder 1 having a slit indicated by Y in FIG.
7 is fixed via a screw 18. 19a
and 19b indicate a pair of upper and lower photodetectors;
Photodetectors 19a and 19b are provided near encoders 16 and 17, as shown in FIG. In addition, in Fig. 1, 20 indicates head 1.
shows the belt cover attached to the top of the

Figures 2 to 5 are diagrams explaining the principle of the device of the present invention, Figure 6 is a block circuit diagram explaining the electrical operation system of the device of the present invention, and Figure 7 is a time diagram of the electrical operation system shown in Figure 6. This is a chart, a to f attached to Figure 7.
correspond to A-F in FIG.

Here, the operating system of the present invention will be explained based on FIGS. 2 to 7 while referring to FIG. 1.

Before the screw tapping process, the positional relationship between the pair of upper and lower encoders 16 and 17 is as shown in Fig. 2A, and the relative position between the slit X ₁ of the encoder 16 and the slit Y ₁ of the encoder 17 is There is a phase difference of φ=φ ₁ as an angle. This phase difference φ ₁
For example, if the diameter of the screw tap used is M ₁ ,
This is determined by the elastic body 13 to correspond to the amount of twist of the screw tap immediately before the breakage torque, and when the tap diameter indicating device (not shown) indicates the diameter of the screw tap to be used as _M1 , Signal A in FIG. 6 changes from logic "0" to logic "1".
When the signal A in Figure 6 changes from logic "0" to logic "1", the infrared LED shown in Figure 2B, for example,
The photodetector (light projector) 19a consisting of a light emitting diode or the like is activated and becomes capable of detecting the torsional torque of the tap with diameter _M1 . This corresponds to point P in FIG.

Next, when the operator turns on the starting switch of the tapping board, E of the control circuit 21 shown in FIG.
The signal changes from logic "0" to logic "1" and the first
The main shaft 2 shown in the figure begins to rotate. This corresponds to point Q in FIG. After that, processing of the workpiece material begins, but if no twist occurs in the elastic body ₁₃ at this time, as shown in _FIG . The phase difference φ ₁ is such that φ ₁ ≠0,
The light receiver 19b consisting of a phototransistor etc. does not receive the light from the light emitter 19a, and only the E signal of the output of the control circuit 21 is logic "1". Therefore, the main shaft 2 shown in FIG. Continue rolling.

On the other hand, if, for example, the diameter of the pilot hole pre-drilled in the workpiece material is less than the specified value for the tap diameter _M1 , the elastic body 13 will gradually twist, causing the encoder 16 to twist. The phase difference φ ₁ between the slit X ₁ and the slit Y ₁ of the encoder 17 also gradually decreases and approaches 0 (zero). When the phase difference φ ₁ becomes φ ₁ =0, the slit X ₁ and the slit Y ₁ overlap on the light detection axis of the emitter 19a and the receiver 19b, as shown in FIG. The light receiver 19b receives the light from. When the light receiver 19b receives the light from the light emitter 19a, the output signal C of the light receiver 19b shown in FIG.
As shown in FIG. 7c, the control circuit 21 changes the normal rotation signal E from the logic "1" to the logic "0" upon receiving the output signal. , the reversal signal F is changed from logic "0" to logic "1", and the main shaft 2 is reversed. This corresponds to point R in FIG.

Note that the diameter of the screw tap is not only M ₁ but also M ₂ ,
There are multiple types such as M ₃ , M ₄ , etc., but here, as an example, a case will be described in which the torsional torque of a screw tap with a tap diameter of M ₂ is detected.
The pair of upper and lower encoders 16 and 17 has slits X ₁ and Y ₁ for torsional torque detection when the screw tap diameter is M ₁ , as well as slits X ₂ for torsional torque detection when the screw tap diameter is M ₂ . and Y ₂ are provided with a phase difference of φ=φ ₂ as relative arrangement angles. The above phase difference φ=φ ₂ has a tap diameter of M ₂
(M ₁ <M ₂ ), which corresponds to the amount of twist of the screw tap just before the breakage torque. Further, near the encoders 16 and 17, in addition to the photodetectors 19a and 19b when the screw tap diameter is _M1 , photodetectors 22a and 22b are provided when the screw tap diameter is _M2 .

In the above configuration, when the tap diameter indicating device (not shown) indicates the diameter of the screw tap to be used to _M2 , the signal A in FIG. 6 becomes logic "0" and the signal B becomes logic "0". It becomes "1". 6th
When the signal A in the figure becomes logic "1" and the signal B becomes logic "1", the photodetector (projector) 22a is activated and becomes in a state where it is possible to detect the torsional torque of the tap with a diameter _M2 . This corresponds to point S in FIG.

Next, when the operator turns on the starting switch of the tapping board, the E signal of the control circuit 21 changes from logic "0" to logic "1", and the main shaft 2 starts rotating. Thereafter, processing of the material to be processed begins. At this time, if twisting does not occur in the elastic body 13, as shown in FIG. 2A, the encoder 16
The phase difference φ ₂ between the slit X ₂ of the encoder 17 and the slit Y ₂ of the encoder 17 is φ ₂ ≠0, and the optical receiver 22b
does not receive light from the light projector 22a, and only the E signal output from the control circuit 21 is in the logic "1" state, so the main shaft 2 continues to rotate normally.

On the other hand, if the diameter of the pilot hole pre-drilled in the workpiece material is less than the specified value for the tap diameter _M2 , the elastic body 13 will gradually twist, causing the encoder 16 to twist. The phase difference φ ₂ between the slit X ₂ and the slit Y ₂ of the encoder 17 also gradually decreases and approaches 0 (zero). and the phase difference φ ₂
When φ ₂ =0, as shown in Fig. 4 A and B, the slit X ₂ and the slit Y ₂
a and the light receiver 22b overlap on the optical detection axes, and the light receiver 22b receives the light from the projector 22a. When the light receiver 22b receives the light from the light emitter 22a,
The output signal D of the light receiver 22b shown in FIG. The reverse rotation signal F is changed from logic "0" to logic "1" and the main shaft 2 is reversed.

In addition, in the above embodiment, the screw tap diameter is
Phase difference φ ₁ between slits X ₁ and Y ₁ when M ₁
and the slit when the screw tap diameter is M ₂
Since the phase difference φ ₂ between X ₂ and Y ₂ is in the relationship φ ₁ <φ ₂ , the slit X ₂ and the slit Y ₂ are connected to the photodetector 22.
Before the slits X ₁ and slits Y ₂ overlap on the photodetection axes of the photodetectors 19a and 19b,
They will overlap on the photodetection axis line of b, but at this time, since the signal A in FIG. 6 is logic "0",
The photodetectors 19a and 19b are never activated. In this way, slits are formed in the pair of upper and lower encoders 16 and 17 with different relative arrangement angles according to the number of types of screw tap sizes, and the same number of photodetectors are arranged and switched as appropriate. By using this device, it is possible to detect the maximum allowable torque of multiple types of screw taps (tap diameters M ₁ , M ₂ , M ₃ , etc.). It can be used as an economical.

In addition, in the explanation so far, we have explained the case of so-called left-handed tapping in which the main shaft 2 rotates to the left, but as shown in the right half of _{FIG. 2} ...
If slits Y, Y ₁ , Y _{2 , .} . . , which are symmetrically phased by φ, φ ₁ , φ ₂ , . . . are provided in the encoder 17 located below the encoder 16, In both cases of right-handed thread tapping and left-handed thread tapping, it is possible to detect the maximum allowable torque amount of the used thread tap.

Furthermore, in order to operate _{the device of the present invention more reliably, as shown in FIG. 5, in addition to providing the slits X, X 1 ,} X _{2 ,} . In the same arrangement as ..., slits x, symmetrically with respect to the center point of the encoder 16.
In addition to newly adding x ₁ , x ₂ , . . . and providing slits Y, Y ₁ , Y ₂ , . . . to the encoder 17,
The slits Y, Y ₁ , Y ₂ , ... are arranged symmetrically with respect to the center point of the encoder 17 in the same arrangement as the slits Y, Y 1 , Y 2 , ...
If y ₁ , y ₂ , ... are newly added and a means for detecting the maximum allowable torque of the screw tap is provided, the main shaft 2
Detection can be performed twice during one rotation, improving detection accuracy. Also, in the unlikely event that one of the torque detection system slits becomes clogged, etc.
Since other detection systems are activated, there is no need to stop the operation of the tapping board due to the above trouble.
This contributes to improving the operating rate of this type of cutting machine.

FIG. 8 shows another embodiment of the present invention, in which the same parts as those in FIG. 1 are given the same reference numerals and their explanation will be omitted.

23 is a pinion formed on the outer periphery of the spindle sleeve 7, 24 is a gear, and the gear 24 meshes with the pinion 23. Further, 25 is a pinion formed on the outer periphery of the main shaft insertion member 15, and the outer diameter and number of teeth of the pinion 25 are the same as those of the spindle sleeve 7.
The outer diameter and number of teeth are the same as the pinion 23 formed on the outer periphery of the pinion 23. 26 is a gear that meshes with the pinion 25, and the outer diameter and number of teeth of the gear 26 are the same as the outer diameter and the number of teeth of the gear 24 that meshes with the pinion 23 formed on the outer periphery of the spindle sleeve 7. A gear shaft 27 supports the gears 24 and 26, and the upper and lower ends of the gear shaft 27 are connected to the bearings 2.
It is supported on the tapping machine head 1 via 8 and 29. One gear 26 of gears 24 and 26
is firmly fixed to the gear shaft 27 by means such as press fitting, and the other gear 24 is loosely fitted to the gear shaft 27 via a bearing 30.
The gear 24 is provided with a slit X, similar to the encoder 16 shown in FIG.
Similarly to the encoder 17 in FIG. 1, the encoder 6 is also provided with a slit Y. That is, in the embodiment shown in FIG. 8, the gear 24 has the function of the encoder 16 shown in FIG. 1, the gear 26 has the function of the encoder 17 shown in FIG. During machining, when twisting occurs in the elastic body 13 corresponding to the maximum allowable torque amount of the screw tap used, the torsion angle of the elastic body 13 is expanded by the rotation of the gears 24 and 26. , the torque detection device having the structure shown in FIG. As the means for enlarging , a belt transmission mechanism may be used instead of the above-mentioned gear mechanism.

[Effect of idea]

According to the present invention, the relative arrangement angle of the slits attached to the pair of encoders located above and below the elastic body is determined by the torsion angle of the elastic body corresponding to the maximum allowable torque amount for each type of screw tap size. In addition, a slit is formed to enable torque detection in the forward and reverse rotation directions of the main shaft and to increase detection frequency during one rotation of the main shaft, and a plurality of photodetectors are arranged near the encoder. , a photodetector is installed that can be selected according to the type of screw tap used, so if excessive torque is generated on the screw tap used during thread tapping, an abnormality is detected and the spindle is reversed, allowing the screw tap to be used. It is possible to prevent the screw tap from breaking, and when replacing the screw tap with a tap of a different size, it is possible to quickly set a photodetector that detects an overload suitable for the tap. In addition, since a complicated numerical processing circuit such as a microcomputer is not required to detect abnormal signals, the structure is extremely simple, and the torque of this type of cutting machine is highly reliable and suitable for practical use. A detection device can be obtained.

[Brief explanation of drawings]

Figure 1 is a vertical sectional view of the main part of a tapping machine incorporating the torque detection device of the present invention, and Figures 2 to 5
6 is a block circuit diagram explaining the electrical operation system of the device of the present invention, FIG. 7 is a time chart of the electrical operation system shown in FIG. 6, and FIG. 8 is a diagram illustrating the principle of the device of the present invention. FIG. 1 is a vertical cross-sectional view of a main part of a tapping machine incorporating a torque detection device different from that shown in FIG. In the figure, 2 is the main shaft, 7 is a spindle sleeve, 13 is an elastic body, 15 is a main shaft insertion member, 16 and 17 are encoders, 19a and 22a are photodetectors (emitters), and 19b and 22b are photodetectors (light receivers). 21 is a control circuit, 23 and 25 are pinions, 24 and 26 are gears, 27 is a gear shaft,
28-30 are bearings.

Claims (1)

[Claims for Utility Model Registration] 1. An elastic body is provided on the outer periphery of the lower end of a spindle sleeve which is supported by the head and rotationally driven, and a first encoder and a second encoder are provided above and below the elastic body. In the tapping board, a photodetector is provided in the vicinity of the first encoder, and the photodetector is actuated when slits formed in both encoders coincide to detect an overload state of the tap. N slits, the number of which is the same as the number of types of screw tap sizes, are formed directly above the second encoder, and N slits are formed at the same radius as each of the slits of the first encoder, and at a relative arrangement angle. Forming N slits each different from each other,
A first encoder and a second encoder are installed above and below the elastic body so as to maintain the relative arrangement angle, and one N encoder is installed at the same radius as each slit of the first encoder. 1. A torque detection device for a tapping board, characterized in that a plurality of photodetectors are arranged, and the operation of the photodetector or the output signal of the photodetector can be selected depending on the tap size. 2. The torsional torque value of the elastic body determined by the relative arrangement angle of the corresponding slits with the same radius formed in the first encoder and the second encoder is the maximum allowable torque amount of each which varies depending on the screw tap size. A torque detection device for a tapping board according to claim 1 of the utility model registration. 3 N slits formed in the second encoder at the same radius positions as the N slits formed in the first encoder, but with different relative arrangement angles, are further formed in the first encoder. The second encoder is formed to have a line symmetry with respect to a radial straight line passing through the center of the N slits formed in the second encoder, and the second encoder is formed to have N slits, and the elastic body is rotated in the clockwise and counterclockwise rotation directions. A torque detection device for a tapping board according to claim 1 or 2, which is capable of responding to torsional deformation. 4. A request for registration of a utility model in which the slits of the first encoder and the slits of the second encoder are formed symmetrically with respect to the center point of each encoder, allowing multiple detections during one rotation of the encoder. The torque detection device for a tapping board according to one item selected from the ranges 1 to 3.