JPS59107866A - Controller for torque of impact wrench - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a torque control device for an ink tightening wrench driven by an air motor, and has a tightening torque control mechanism using a detection device using light reflection and a torsion hole. It has an extremely simple structure, can be controlled accurately, and the control value can be varied.

As such a control device, Japanese Patent Application Laid-Open No. 55-164
There is a device described in Japanese Patent No. 482.

However, this known device uses a fluid element, and the main valve that cuts off the supply of air to the air motor is also operated by air pressure, so the response speed is slow and clean air must be supplied because it uses a fluid element. was there.

This invention aims to completely eliminate the drawbacks of the above-mentioned conventional devices, and uses an electromagnet as the main valve that uses a detection device that uses light reflection to shut off the supply of air to the air motor. The object of the present invention is to provide a control device that is a closed type and can provide stable operation with a fast response speed.

That is, in this invention, an impact mechanism driven by an air motor is provided with a torsion bar to which a tightening tool is attached at the front end, and only one end of a cylindrical spindle case fitted outside the tone bar is attached to the tone bar. The curved end of the spindle case is a four-turn valve that opens or closes the exhaust hole provided in the torsion bar when the torsion bar is twisted. The impact wrench is equipped with eight main valves that are opened and closed by detecting the pressure change in the air passage when the rotary start valve is opened or closed, in the middle of the passage that sends compressed air to the air motor. A moving member that moves forward and backward in response to pressure changes in the passage toward the main valve is provided, and a detection device that is also an optical fiber sensor that is sensitive to the movement of this member, and a signal from this detection device controls the electromagnet for opening and closing the main valve. It is equipped with a control circuit that converts the torsion of the torsion bar into changes in air pressure, and uses an optical fiber sensor to detect changes in the position of advancing and retracting members such as diaphragms due to this pressure change to control the main valve. It has excellent effects such as extremely fast response speed and no risk of malfunction.

The details of the present invention will be explained below based on an embodiment shown in the accompanying drawings.

In the figure, 1 is a handle of an impact wrench, which has an air port 2 and an air passage 3, and a large opening valve V+ in FIG. 4, which is operated by a lever 4 attached to the handle 1. This valve 1 closes the valve port using a bullet and air pressure when the lever 4 is not pressed, and opens the valve port when the lever 4 is pressed.

Further, a main valve v2 and a fixed line valve v8 are provided in the base of the handle 1, a cylindrical tooth 5 is provided in the upper part of the handle 1, and an air motor 6 is installed in the case 5. . Further, a rotation direction switching valve v4 for the air motor 6 is provided at the lower part of the case 5, and this valve v4 is manually operated using a lever.

Reference numeral 7 denotes a hammer case fixed to the front part of the case 5. A hammer frame 8 is rotatably installed inside the hammer case 7, and an anvil 9 is rotatably attached to the center of the frame 8. Torsion bar 10 at the front of 9
is provided. Further, a driver 11 is rotatably fitted into one rear part of the hammer frame 8.
is connected to the rotor shaft of the air motor 6 by a spline.

A hammer 12 is rotatably attached to the hammer frame 8, and when there is almost no resistance acting on the tone bar 10', the rotation of the rotor of the air motor 6 is transmitted to the driver 11, anvil 9, and torsion bar 10 to continuously rotate the hammer 12. It rotates, but resistance is added to tone 4 number 10! When it stops rotating, the driver 11 and hammer 12, which continue to rotate, strike the stopped anvil 9 and rotate the torsion bar 10. Such an impact mechanism is far more advanced than the known impact mechanism. You can use this mechanism. In addition, an insertion part 14 for various tightening tools 13 suitable for the pole 14 nut to be tightened is provided at the tip of the torsion bar 10,
Further, the tip of the spindle case 15 is placed over the base of this part, and the rear end is fixed to the tone bar 10. This spindle case 15 is a rigid tube, and the torsion bar 1
0 outside III, and can rotate freely with respect to the bar 10 except for the rear end, and the front end is provided with an exhaust hole 16' corresponding to the exhaust hole 16 provided in the bar 10. Two exhaust holes 16, 16' form a rotation stop valve v5,
When the torsion bar 10 is not twisted as shown in FIG.
is open, and when the torsion bar 10 is twisted, the two exhaust holes 16 and 16' are shifted as shown in Fig. 3, and the valve v6 is opened.
It should be closed.

In the circuit diagram of FIG. 4, 17 is a compressed air source, and this air source 17 communicates with the air passage 3 via the inlet valve 2, and the passage 3 connects the main valve 2 and the filter element 18 of FIG. There is a fixed throttle valve V8 through it. Main valve v
2 is slidably fitted into the bushing 19 as shown in FIG.
The electromagnet 21 is connected to a control circuit 23. The electromagnet 21 is connected to a control circuit 23.

In this embodiment, the electromagnet 21 uses a pull-type solenoid, which shuts off the main valve (2) when it is energized. The passage 28 with the fixed throttle valve V8 leads to the fixed throttle valve v7 via a manually adjustable needle valve v6, as shown in FIG. This valve v7 is a venturi type provided on the rear cover 27 of the case 5 in FIG. 10 valves ■6 communicate with the exhaust port 16. A small spine is provided at the narrowest part of the throttle valve v7, and this passage 26 is communicated with the position detection device A via a passage 29 provided in the rear cover 27, as shown in FIG.

This device A has a reciprocating member 31 that moves forward and backward by a diaphragm 30, and this member 31 is provided with a black part a and a white part A, and this part is detected by a reflective optical fiber sensor 32. Connected optical fiber 33
is led to a photoelectric conversion type intensifier 34, and its output circuit is connected to the control circuit 23. In this embodiment,
It is assumed that the contacts on the amplifier 34 side close when the reflected light enters.

Further, the chamber 35 at the front part of the diaphragm 30 is connected to the passage 29.
The reciprocating member 31 communicates with the spring 3 in the rear chamber 35'.
6 in the direction of the diaphragm 30, and this spring 36
Adjust the elasticity of the screw 3. It can be adjusted freely by adjusting the angle.

Note that 38 in FIGS. 4 and 5 is a switch that is opened and closed by the trigger lever 39, and is connected to the control circuit 23. This trigger lever 39 is linked to the Fi lever 4°, and the switch 38 can be opened and closed only by operating the lever 4. do.

Next, to explain the action, press the lever 4 and press the large mouth valve V+.
When opened, compressed air from the compressed air source 17 enters the passage 3 from the air port 2 and passes through the main valve ■2 → switching valve ■4.
- The tightening tool 1 can be installed in the insertion part 14 by rotating the rotary shaft of the motor 6, the driver N11, the hammer frame 8, the anvil 9, and the torsion bar 10.
Turn the nut etc. by 3.

On the other hand, a part of the compressed air passes through the fixed throttle valve Va and is depressurized appropriately, and flows from the passage 28 to the needle valve 6, as shown in Fig. 3. Although it is open, the air pressure in the passages 24 and 25 is Close to atmospheric pressure.

Therefore, the pressure in the passages 26, 29 and the chamber 35 becomes negative pressure due to the Venturi mechanism, and the pressing force of the spring 36 (Thus, since the diaphragm 3o and the member 31 are moving toward the chamber 35 side, the black part a It faces the optical fiber sensor 32.

At this time, since the optical fiber sensor 32 does not receive reflected light, no optical signal is sent to the amplifier 34, and the control circuit 23 does not operate, so the main valve 2 remains open.

Due to the above action, the nut, etc. is turned and enters the tightening U stage, and the Q1 impact mechanism starts its action, applying a strong torque to the torsion bar 10. Due to the resistance of the giant nut, etc., the insertion portion 14 of the torsion bar 10 When the rotation of the torsion bar 10 is inhibited, the torsion bar 10 begins to twist.

In this state, the rear end of the outer spindle case 15 is fixed to the torsion bar 10, and the front end is free with respect to the bar 10. In contrast, only the spindle case 15 rotates, and as a result, the exhaust hole 16 and the exhaust hole 16' are misaligned, as shown in FIG.
closes. When the valve v5 closes, the air pressure in the passage 24.25 increases, with the result that the air pressure in the passage 26.29 and the chamber 3 increases.
The air pressure inside 5 also increases.

This pressure acts on the left side of the diaphragm 30, and the advancing/retracting part 31 moves toward the chamber 35' against the spring 36, and the white part of the advancing/retracting part 31 moves to the optical fiber (- position of the sensor 32). The optical fiber sensor 32 receives the reflected light.Therefore, a signal is sent from the amplifier 34 to the circuit 23.
3, ゛'' - The triggering magnet 21 is energized.

When the electromagnet 21 is energized, the main valve v2 moves to the left in FIG. 2 and blocks the air from the passage 3 toward the air motor 6, so that the air motor 61-j: mates.

At this time, when the air motor 6 is stopped with the lever 4 pressed down, the torsion bar 10 is restored and the valve 5 is opened, so the passage 26, 29 and the chamber 35 become negative pressure again, and the diaphragm 30 moves forward and backward. The member 31 moves to the chamber 35 side, and the black part a comes to a position opposite the optical fiber sensor 32, but after the circuit 23 turns off and the electromagnet 21 is temporarily excited, the electromagnet 21 remains in its excited state. Make sure to do so.

Thereafter, when the lever 4 is released from the pressure, the valve V+ closes, and the air is supplied to the passage 3 during compression.

At the same time, the switch 38 is also opened, and the excitation state is released.
Return to initial state.

In addition, in the above embodiment, the pressure change take-out part was provided at the fixed throttle valve v7 at the rear of the impact wrench, but this pressure change take-out part can be taken out from any part of the pipe line from fixed throttle valves ■7 to ■6. The same effect can be achieved even if

Furthermore, the pressure change detection section is composed of a diaphragm 30, a reciprocating member 31, a spring 36, a sensor 32, etc.
It is not limited to this structure.

FIG. 6 is a longitudinal sectional view showing another embodiment of the detection device used in the torque control device of the present invention. In this figure, 100 is a diaphragm, 101 is a reciprocating member fixed to the diaphragm, C is a light reflecting portion thereof, 102 is a reflective optical fiber sensor, and 103 is a pressure input portion. Further, this sensor 102 is connected to the amplifier 34 and control circuit 23 shown in FIGS. 4 and 5.

In the case of this embodiment, when a pressure signal is input from the pressure input section 103, it is converted into a movement of the diaphragm 1oo, and the forward/backward movement 101 provided on this diaphragm 100 is also displaced.

In this way, since the advancing and retracting member 101 is displaced, the tip of the reflective optical fiber 7, which is incident on the 102, also changes.
The signal output from the optical fiber sensor 102 changes. By observing the output from this optical fiber sensor 102, the tightening torque of the bolt can be determined.

In the above two embodiments, a reflective optical fiber sensor is used as the optical fiber sensor, but the same effect can be obtained even if a transparent optical fiber sensor is used.

In addition, the pressure can be extracted by increasing the pressure as the torsion bar is twisted, as shown in the example.
A possible method is to reduce the pressure when the torsion bar is twisted.

As stated above, the present invention uses a 1-yeon bar as the torque detection part, converts the twist of the 7-yon bar into a change in air pressure, and converts the pressure change into a change in the position of the diaphragm. The change in the position of the diaphragm is converted into a change in the amount of light by an optical fiber sensor, and this change in light amount is converted into a change in the amount of electricity by a photoelectric element.The main valve is controlled by detecting the amount of electricity, so it can be operated at high speed. You can get a good response. Additionally, there is no risk of malfunction due to moisture or dust in the air, and the device can be made smaller and lighter. Furthermore, the torque control range can be easily adjusted.

Note that the device of the present invention can be applied not only to the impact wrench shown in the embodiment, but also to other nut runners and various pneumatic tools. Therefore, the device of the present invention is highly effective in increasing the precision of torque control, reducing the size of the device, and improving reliability, and has an extremely wide range of applications.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view showing an example of an impact wrench embodying the present invention, Fig. 2 is an enlarged rear view of a partially longitudinal sectional view of the same as above, and Fig. 3 [, II is a bottom view of the spindle case tip in various states. , FIG. 4 is a circuit diagram, FIG. 5 is a block diagram, and FIG. 6 is an enlarged longitudinal sectional side view showing another embodiment of the detection device. 2... Air inlet, 3... Air passage, 6... Air motor, 10... Torsion bar, 13... Tightening tool, 15... Spindle case, 16... Exhaust hole, 2
1... Electromagnet, 23... Control circuit, 31,101.
・・Advancing/retracting member, 32°102・・Optical fiber sensor,
A...Detection device. Patent applicant: Japan Pneumatic Industry Co., Ltd. Agent: Kama 1) Bun 2

Claims (1)

[Claims] 1. An impact mechanism driven by an air motor is provided with a torsion bar to which a tightening tool is attached at the front end, and only one end of a cylindrical spindle gauge fitted on the outside of this torsion bar is torsioned. 7-1 A letter of appreciation for opening or closing the exhaust hole provided in the tokitone yonbar, which is fixed to the top and is rotatable relative to other haton yonbars, and is twisted at the other end of the spindle coos. A rotary start valve is provided, and a main valve is provided in the middle of the passage for sending compressed air to the air motor, which is opened and closed by detecting a pressure change in the air passage when the rotation stop valve is opened or closed. The impact wrench is equipped with a detection device consisting of a reciprocating member that moves forward and backward according to pressure changes in the passage toward the rotary stop valve, and an optical fiber sensor that is sensitive to the movement of this member, and a signal from this detection device is used to detect the main body. A torque control device for an impact wrench, characterized in that it is equipped with a control circuit that controls an electromagnet for opening and closing a valve. 2. The torque control device for an impact wrench as set forth in claim 1, wherein the detection device includes an adjusting member such as a screw and a spring that adjusts the amount of movement of the advancing/retracting member.