JPS6047070B2 - A power tool that can detect the rotation angle after a certain torque - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pneumatic tool that can detect the rotation angle of a drive shaft after a certain torque, and therefore can discriminate and control the rotation angle of the drive shaft after a certain torque.

Conventionally, for pneumatic tools such as impact wrenches and nut runners, the reaction force of the rotational force of a drive shaft driven by an air motor is applied to a torsion bar, and the tightening torque is detected based on the torsion angle of the torsion bar. , one in which the tightening torque is controlled is known.

However, although this type of pneumatic tool can detect tightening torque, it cannot accurately detect the rotation angle of nuts, etc. after a certain tightening torque, and cannot accurately control the rotation angle. There are drawbacks.

An object of the present invention is to eliminate the above drawbacks by accurately detecting the rotation angle of the drive shaft after a certain tightening torque, and determining and controlling the rotation angle of the drive shaft after the certain tightening torque. The purpose of the present invention is to provide a new pneumatic tool that can be used.

In order to achieve the above object, the present invention provides a torque sensor that detects the rotation angle of a torsion bar that receives rotational reaction force of a drive shaft driven by an air motor, and a torque sensor that detects the rotation angle of the shaft of the air motor from the rear of the air motor. A rotation angle sensor is provided to detect a constant tightening torque based on an output signal of the torque sensor, and to cause the rotation angle sensor to detect a rotation angle of the drive shaft after the constant tightening torque. It is characterized by what it did.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments. In FIG. 1, 1 and 2 are nutrunners having the same structure fixed in parallel to the underframe 3, and 4 and 5 are electromagnetic switching valves that control the supply of air to the nutrunners 1 and 2, respectively.
6 is a torque-angle control device.

The nut runner 1 transmits the rotational force of the air motor 11 to the drive shaft 1 through a planetary gear mechanism 12, which is an example of a transmission mechanism.
3, the rotational force and rotational speed of the air motor 11 are increased or decreased and transmitted to the drive shaft 13.

The reaction force of the rotational force of the drive shaft 13 is applied to the upper end of the torsion bar 14 via an internal gear (not shown) of the planetary gear mechanism 12 and the case 12a.

The torsion bar 14 is connected to the drive shaft 13 as shown in FIG.
The flange portions 14a at the lower end are fixed to the underframe 3 with bolts 15, as shown in FIG.

Therefore, the nut runner 1 is fixed to the underframe 3 via the torsion bar 14. - The shaft bar 14 is twisted by a reaction force corresponding to the tightening torque of the drive shaft 13. A bar 21 extending in the radial direction of the case 12a is fixed to the case 12a of the planetary gear mechanism 12, so that when the torsion bar 14 is twisted, the bar 21 rotates together with the case 12a.

A torque sensor consisting of a limit switch 22 is provided at a position opposite to the tip of the bar 21, and the torque sensor is provided with a limit switch 22.
When the tightening torque reaches a certain value and the torsion bar 14 is twisted by a certain angle, a torque sensor 2 is installed at the tip of the lever 21.
2 to press the torsion bar 1 to the torque sensor 22.
A constant torque is detected through the twist angle of 4. When the torque sensor 22 detects a constant torque, the output signal from the torque sensor 22 turns off the electromagnetic switching valve 4, stops driving the nut runner 1, and causes the torque angle control device 6 to tighten. It is designed to output a signal indicating that the torque has reached a constant value. On the other hand, a rotation angle detection shaft 25 is fixed to a rotation shaft (not shown) of the air motor 11. The center of the disc 27 is fixed at the tip, and one or more through holes 26 are provided at equal intervals on a circle with a constant diameter on the disc 27.

Further, as shown in FIG. 4, a U-shaped (non-contact rotation angle sensor 28 It is provided in the frame 3, and as the air motor 11 rotates, the light emitting element and the light receiving element are opposed to each other via the circular through hole 26, so that the rotation angle sensor 28 outputs pulses.The rotation angle sensor 28 After the torque sensor 22 outputs a signal that detects a predetermined constant torque Ts (snag torque), the pulse is sent to the counter 6 via the amplifier 65 of the torque angle control device 6, as shown in FIG.
6. The counter 66 counts the number of pulses, and comparators 67 and 68 output a signal representing the rotation angle 0 of the drive shaft 13 after the snug torque Ts.
is being input. The comparator 67 is a target angle setting device) 69
A signal representing the target angle θc input from the drive shaft 13
When the actual rotation angle θ becomes the target rotation angle θc, the drive circuit 70
A signal for turning off the electromagnetic switching valve 4 is outputted via the switch. On the other hand, the comparator 68 receives a signal representing the lower limit rotation angle θ1 output from the lower limit setting device 71 and an upper limit rotation angle θ output from the upper limit setting device 72.
2, the actual rotation angle 0 is compared with the lower limit rotation angle θ1 and the upper limit rotation angle θ2, and if θ≦θ1, the lamp 52 is turned on via the drive circuit 73. When θ1 and θ<θ2, a signal is output to turn on the lamp 51 via the drive circuit 73, and when θ2≦θ, the drive circuit 73 outputs a signal to turn on the lamp 51.
A signal for lighting the lamp 53 is outputted via the . Therefore, as shown in FIG. 6, the rotation angle θ of the drive shaft 13 after the snug torque Ts is within the allowable range, that is, θ1 - θ<θ2 with respect to the target rotation angle θc.
If so, the lamp 51 indicating the pass status lights up and θ≦θ1
In the case of θ≧θ2, the lamp 52 indicating the under-rotation angle condition lights up, and when θ≧θ2, the lamp 5 indicating the over-rotation angle condition lights up.
3 will be lit. On the other hand, the nut runner 2 has the same structure as the nut runner 1, and is equipped with a limit switch 32 as a torque sensor and a rotation angle sensor 38, and their output signals are used for torque angle control. In the device 6, the signal is processed in the same way as in the nutrunner 1.

On the other hand, lever switches 41 and 42 are provided at both ends of the lower part of the underframe 3, respectively. When the lever switch 41 is turned on, both the electromagnetic switching valves 4 and 5 are turned on, air is supplied to the air motors of the nut runners 1 and 2, and the nut runners 1 and 2 are rotated together. Lever switch 42
When turned on, both the electromagnetic switching valves 4 and 5 are turned on, and the nut runners 1 and 2 are driven, and the torque sensor 22 is turned on.
, 32 are both detecting snug torque, the signals from the rotation angle sensors 28, 38 are input to the counter of the torque angle control device 6. Above 1.
The Lukoo angle control device 6 controls the drive shaft 1 of the nut runners 1 and 2 based on the output signals from the respective torque sensors 22 and 32.
When the respective tightening torques 3 and 30 exceed a certain torque, that is, the snug torque Ts, lamps 46 and 4 turn on, respectively.
7, and further includes a circuit (not shown) for logically determining the output signals from the torque sensors 22, 32, and a circuit (not shown) for determining the output signals of the logic circuit when the tightening torques of both the drive shafts 13, 30 are both greater than or equal to the snug torque Ts. It is provided with a comprehensive TORF pass lamp 48 that lights up.

Further, the torque angle control device 6 is configured to control the drive shaft 3 in order to indicate the tightening torque of the nut runner 2 in the same manner as the lamps 51, 52, 53 indicating the tightening torque of the nut runner 1.
The rotation angle θ after the snug torque Ts of 0 is (θ≦θ
1), the lamp 55 lights up in the case of (θ1〈O〉θ2
), and a lamp 56 that lights up when (θ2≦θ), and further includes a total torque passing lamp 48 and a passing lamp that light up when both passing lamps 46 and 47 are lit. It includes a general pass lamp 58 that lights up when both pass lamps 48, 51, and 55 turn on, and a general fail lamp 57 that turns off when any one of the pass lamps 48, 51, and 55 goes out. Note that 59 is a power lamp, and 61 is a manual automatic changeover switch. The pneumatic tool having the above configuration operates as follows.

First, the connectors 81 and 82 at the tips of the drive shafts 13 and 30 are fitted into nuts (not shown) to be fastened, respectively. Next, the lever switch 41 on the right side in FIG. 1 is turned on, both the electromagnetic switching valves 4 and 5 are turned on, and the nut runners 1 and 2 are rotated together to tighten the nut.

When the tightening torque of each nut reaches the snug torque Ts, the torque sensors 22, 32 are turned on due to the twisting of the torsion bars 14, 31, turning off the magnetic switching valves 4, 5, and the nut runners 1, 2 are rotated. to stop.

Then, the lamps 46 and 47 of the torque angle control device 6 and the total torque pass lamp 48 are turned on. Next, when the lever switch 42 on the left side in FIG.
, 2, the rotation angle sensors 28 and 38 start reading the rotation angles of the drive shafts 13 and 30, and input pulses to the torque angle control device 6.

The torque angle control device 6 performs signal processing as described above, and when the rotation angle 0 after the snug torque Ts of the drive shafts 13, 30 reaches the target rotation angle θc, the electromagnetic switching valve 4
Nut runner 1 is output by outputting a signal to turn off each nut runner 1.
, 2 are stopped. However, the drive shafts 13 and 30 do not necessarily stop at the moment when the target rotation angle 0c is reached due to the delay in transmission of the above-mentioned signals and the inertia of the nutrunners 1 and 2. On the other hand, at this time, the torque angle control device 6 sets the rotation angle θ after the snag torque Ts when the drive shafts 13, 30 actually stop to a lower limit value θ1, by the operation of the counter 66, comparators 67, 68, etc. Upper limit value θ2
The rotation angle θ of the drive shaft 13 is (θ
The pass lamp 51 is lit when the rotation angle 0 of the drive shaft 30 is (θ1 x θ<θ2), and the pass lamp 54 is lit when the rotation angle 0 of the drive shaft 30 is (θ1 x θ<θ2). When both the comprehensive torque pass lamps 48 are lit, the comprehensive torque pass lamp 58 is lit.

In other cases, the overall failure lamp 57 is turned on. As a result, the drive shafts 13, 30 after the snug torque Ts
The rotation angle can be accurately determined and controlled. In the above embodiment, the lever switch 41 controls the drive of the nut runners 1 and 2.
, 42, the lever switch 41 is used as the starting switch, and the lever switch 4
The subsequent operations may be performed automatically without operating step 2.

Furthermore, it goes without saying that the present invention can be applied to any number of "θ" pneumatic tools, not just two.

As is clear from the above description, the present invention includes a torque sensor that detects a constant rotation angle of a torsion bar that receives a rotational reaction force of a drive shaft driven by an air motor, and a torque sensor that detects a rotation angle of a shaft of the air motor from the rear of the air motor. A rotation angle sensor is provided to detect a constant tightening torque based on an output signal of the torque sensor, and the rotation angle sensor is configured to detect a rotation angle of the drive shaft after the constant tightening torque. Therefore, the rotation angle of the drive shaft after the constant tightening torque can be accurately detected, and the rotation angle of the drive shaft after the constant tightening torque can be determined and controlled. Further, the present invention includes a rotation angle sensor that detects the rotation angle of the shaft of the air motor from the rear of the air motor,
Since there is no rotation angle sensor installed around the drive shaft, the drive shaft can be inserted into narrow spaces where nuts and other equipment are crowded, and tightening operations can be performed without interfering with nuts or other equipment. Moreover, the rotation angle of the air motor shaft after a certain tightening torque can be detected accurately and easily, and the practical effect of nut tightening can be achieved.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is a sectional view of the torsion bar portion of the nut runner, and Fig. 3 is a schematic diagram of an embodiment of the present invention.
Figure 4 is a perspective view of the rotation angle sensor, Figure 5 is a block diagram of the main parts of the torque angle control device, and Figure 6 is the relationship between the rotation angle of the drive shaft and the tightening torque. It is a line diagram showing a relationship. 1, 2... Nut runner, 11... Air motor, 13, 30... Drive shaft, 14, 31...
... Torque sensor, 22, 32 ... Torque sensor, 28, 38 ... Rotation angle sensor.

Claims (1)

[Claims] 1 Rotate the drive shafts 13 and 30 with the air motor 11,
A pneumatic tool that tightens an object to be tightened, applies a reaction force of the rotational force of drive shafts 13 and 30 to torsion bars 14 and 31, and detects the tightening torque based on the rotation angle of the torsion bars 14 and 31. In, the torsion bar 14,
31 to detect a constant torque, and rotation angle sensors 28, 38 to detect the rotation angle of the shaft of the air motor 11 from the rear of the air motor 11. sensor 22,
32, the constant tightening torque is detected, and the rotation angle sensors 28, 38 are made to detect the rotation angle of the drive shafts 13, 30 after the constant tightening torque. A pneumatic tool that can detect the rotation angle after a certain torque.