JP2716161B2 - Screw seat confirmation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention detects a gap (seating) between a seating surface of a screwed body such as a bolt and a nut and a seating surface of an object to be fastened. The present invention relates to a seating confirmation device capable of confirming fastening of a screw tightening body.

[Conventional technology] In order to confirm the degree of tightening of a bolted body such as a bolt or a nut to a workpiece by a screwing machine, it is necessary to roughly classify the method into a torque detection method and a seating method. it can.

[Problems to be Solved by the Invention] In the former torque detection method, complete screw tightening is not completed, for example, when the resistance of the screwing force due to the deformed or deformed male and female screws is large. When the set tightening torque value is reached, erroneous tightening (erroneous operation) may occur. In the latter method of confirming seating, a microswitch, a proximity sensor, or the like is used to detect the amount of gap between the seating surface of the screw fastener and the seating surface of the object to be fastened. With the seating confirmation method, only rough determination can be made, and it is difficult to reliably determine whether or not a person is seated.

[Means for Solving the Problems] The present invention has been made in view of such a situation. In particular, when the screw tightened body is seated using ultrasonic waves, and when the screw tightened body is not seated, the seated state is better. Focusing on the fact that the sound pressure reflectivity of the fastening member's seat surface decreases and the voltage level of the fastening member's seat surface echo decreases, a seating confirmation device that can accurately confirm the seating of the screw tightening body is provided. To provide.

[Examples] The present invention will be described in detail below based on examples shown in the drawings.

In FIG. 1, reference numeral 1 denotes a robot device of an automatic screw tightening machine, and a bracket 3 is attached to a leading end of a robot arm 2 of the robot device. A seating confirmation device 5, which is the device of the present invention, is mounted and supported. Next, the mechanism of the seating confirmation device 5 will be described with reference to FIG. Reference numeral 6 denotes a support cylinder which is vertically attached by the bracket 3 and is attached by a mounting screw 7. A vertical support shaft 8 is supported by the support cylinder 6 so as to be vertically movable. A flange 9 is integrally formed at the lower end of the housing. A transducer holder 10 is provided on the lower surface of the flange 9.
Flanges 11 are joined, and both flanges 9, 11 are joined by mounting screws 12. Reference numeral 13 denotes a transducer fitted and held inside the transducer holder 10, and the transducer 13 is fixed in the transducer holder 10 by mounting screws 14. Reference numeral 15 denotes a socket screwed to the lower side of the transducer holder 10, and a head 17 of a screw fastener 16 is loosely fitted into the socket 15. Reference numeral 18 denotes a flange portion 16 formed on the outer periphery of the support cylinder 6 and a flange 9 of the support shaft 8.
And a spring 20 for always urging the support shaft 8 downward, is attached to the upper end of the support shaft 8 to prevent the support shaft 8 from falling out of the support cylinder 6. Stopper screw.

The above is the structure of the seating confirmation device 5 of the present embodiment. Next, the operation thereof will be described. In FIG. 2, the screw fastening member 16 is a member to which the fastening member 21 is screwed.
The head seating surface 17 'of the screwed body 16 and the seating surface of the object 21
The gap a of 21 'is measured to detect whether or not the object 21 is seated.

Therefore, when the detection is performed, the head 17 of the screw fastening body 16 fastened to the fastened body 21 by the screw fastening machine 4
The socket of the seating confirmation device 5 is fitted, and the transducer 13 is joined to the upper surface of the screw fastener head 17 by using the elastic pressure of the spring 18. Then, the ultrasonic pulse generator 22 shown in FIG.
Transmit the ultrasound to 13. By transmitting the ultrasonic wave to the transducer 13, the echo voltage output from the transducer 13, that is, the reflected voltage at the seating surface 21 ′ of the object 21 is converted into an oscillograph 25 via the receiver 23 and the gate circuit 24.
Monitored at. That is, the greater the gap a between the seating surface 17 'and the seating surface 21', the higher the echo voltage is output. That is, if the gap a is small and the seating is completed, the echo voltage is low. Therefore, if the echo voltage is higher than the set value, it means that the seating has not been completed.
If a display or an alarm is generated at 26, it is easy to detect that the seating is uncertain. If the seating is uncertain, re-fastening is performed again by the screw fastening machine 4, and then re-inspection is performed by the seating confirmation device 5, and if the seating is completed, the next screw fastening is performed.

As described above, according to this embodiment, the echo 13 obtained by joining the transducer 13 to the upper surface of the head 17 of the screw fastening body 16 screwed to the fastening body 21 and supplying ultrasonic waves to the transducer 13 is obtained. Detects voltage strength and tightens screw
It can detect 16 seating situations appropriately and accurately.

In the above-described embodiment, the seating confirmation device 5 is adjacent to the screw fastening machine 4, but is not limited to this.
The operator may carry the seating confirmation device 5 alone and carry it alone.

[Effects of the Invention] As described above, the present invention provides a transducer 13 having an oscillating surface joined to the upper surface of a screw fastener head 17, and an ultrasonic pulse generator 22 for transmitting ultrasonic waves to the transducer.
A receiver 23 for receiving an echo signal from the transducer, and a gate circuit for receiving the signal from the receiver and the signal from the ultrasonic pulse generator and detecting the echo voltage level of the seat surface of the object 21 Since it is a screw seating confirmation device having 24
By supplying the ultrasonic waves to 13, the obtained echo voltage strength can be detected, and the seating state of the screw fastener 16 can be properly and accurately detected.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an embodiment of the present invention, FIG. 2 is a cross-sectional explanatory view of only a screw seat confirmation device, and FIG. 3 is a processing circuit diagram thereof. DESCRIPTION OF SYMBOLS 1 ... Robot, 2 ... Arm 3 ... Bracket, 4 ... Screw fastening machine 5 ... Seating confirmation device, 6 ... Support cylinder 7 ... Mounting screw, 8 ... Vertical support shaft 9 ... Flange 10 ... … Transducer holder 11… Flange, 12… Mounting screw 13… Transducer, 14… Mounting screw 15… Socket, 16… Screw fastener 17… Head, 17 '… Seat 18… Spring , 19… Flange 20… Stopper screw, 21… Fastened body 21 ′… Seat

Claims (3)

(57) [Claims] 1. A transducer (13) having an oscillating surface joined to the upper surface of a screw fastener head (17), and an ultrasonic pulse generator (22) for transmitting ultrasonic waves to the transducer.
And a receiver (23) for receiving an echo signal from the transducer; receiving a signal from the receiver and a signal from the ultrasonic pulse generator to adjust an echo voltage level on a seat surface of the object (21). An apparatus for confirming seating of a screw, comprising a gate circuit (24) for detection. 2. A power screw tightening device comprising the above seating confirmation device. 3. A screw tightening robot device comprising the seating confirmation device and a power screw tightening device.