JPH0224587Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is for detecting floating screws in screw tightening units attached to versatile industrial robots used for inserting, extracting, assembling parts, etc. in high-mix, low-volume production. Regarding equipment.

BACKGROUND OF THE INVENTION Recently, this type of versatile industrial robot has been attracting attention, and as the use of industrial robots has increased, various work tools have been developed. Among these, screw tightening units are important when performing assembly work, and highly versatile screw tightening units have been developed in order to make effective use of highly versatile robots. As shown in FIG. 3, this screw tightening unit has a driver bit 35 which is rotatable and lowerable by a motor 33. A guide sleeve 38 is disposed around the driver bit 35 so as to be movable integrally or relatively movably.
A predetermined screw can be attracted to the tip of the driver bit 35.

Problems to be Solved by the Invention In this screw tightening unit 25, there is a difference between the amount of descent of the driver bit 35 and the amount of insertion of the screw when tightening the screw, but the motor 3 is designed to absorb this difference.
The drive shaft 33a of No. 3 and the driver bit 35 are connected by a spring 51 so as to be relatively movable. Therefore, when detecting a floating screw during screw tightening, the dog 42 is fixed directly to the driver bit 35, and the sensor 40 that detects the dog 42 is moved close to the driver bit 35 and together with the guide sleeve 38. Not only does the installation require troublesome work, but the installation position is also limited, making adjustment difficult.

Means for Solving the Problems The present invention aims to eliminate the above-mentioned drawbacks.
A driver stand is arranged that moves up and down by the operation of a cylinder. A driver bit, which rotates in response to the rotation of the motor, is arranged on the driver stand so as to move together with the driver bit. Further, a guide sleeve is arranged to enclose the driver bit, and this guide sleeve is attached to the suction sleeve. Moreover, this suction sleeve is held by a holding sleeve attached to the driver stand, and the suction sleeve is biased away from the holding sleeve by a spring.

A sensor is attached to the driver base so as to move therewith, and the sensor is configured to be located close to the side of the suction sleeve. Further, a dog is fixed to a side of the suction sleeve that moves together with the guide sleeve at a position corresponding to the sensor and spaced a predetermined distance from the sensor.

On the other hand, an air supply source is connected to the first supply/discharge port of the cylinder via a pressure reducing valve, and the pressure reducing valve is adjusted so as to reduce the pressing force when the rod of the cylinder is lowered.

Function With the above device, there is no need to attach the dog directly to the driver bit, and there is no need to attach the sensor close to the driver bit, and the dog is fixed to the driver stand side that moves together with the driver bit, and the dog is attached to the guide sleeve. Since it can be exposed and fixed to the outside, its assembly work is extremely simple, and its maintenance management is also simple.

Embodiment An embodiment of the present invention will be described below based on the drawings. In FIGS. 1 and 2, 1 is an arm 3 of an articulated industrial robot, which is configured to rotate by receiving rotation from a motor (not shown) via a reducer (not shown). has been done. A through hole portion 4 is bored at the tip of the arm 3, and a vertical groove 5 is formed so as to communicate with the through hole portion 4. A fixing shaft 26 of a screw tightening unit 25 is inserted through the through hole 4, and the fixing shaft 26 is fixed to the tip of the arm 3 by two mounting bolts 31 located across the vertical groove 5. ing. This fixed shaft 26 has a sufficient length to be movable, and brackets 27 and 27a are fixed to its upper and lower ends, respectively. This bracket 27, 27a has 2
A book guide shaft 28 is fixed, and a driver stand 29 is slidably guided on this guide shaft 28. This driver stand 29
The cylinder 3 fixed to the bracket 27 is
0 rods 30a are connected to each other, and are configured to give the driver stand 29 a lifting motion.
The cylinder 30 has a first supply/discharge port 47 and a second supply/discharge port 48 , and the first supply/discharge port 47 has a pressure reducing valve 49 .
An air supply source (not shown) is directly connected to the second supply/discharge port 48 via the second supply/discharge port 48, and is configured so that the pressing force thereof is reduced when the rod 30a is lowered.

Further, the driver body 3 is mounted on the driver stand 29.
2 is fixed, and a motor 33 is fixed to this driver body 32. A drive shaft 33a of this motor 33 is located below, and a connecting shaft 34 is connected to this drive shaft 33a. Further, this connecting shaft 34 is rotatably held by the driver main body 32, and furthermore, a driver bit 35 is connected to the lower end of the connecting shaft 34. It is configured so that it can be moved freely.

On the other hand, the holding sleeve 3 is attached to the driver stand 29.
6 is fixed, and this holding sleeve 36 holds a suction sleeve 37 to which a guide sleeve 38, which will be described later, is fixed. This retaining sleeve 3
6 and the suction sleeve 37, a spring is disposed between the suction sleeve 37 and the suction sleeve 37 to urge the suction sleeve 37 away from the holding sleeve 36. The suction sleeve 37 also has a suction section 37a, and the suction section 37a has an air chamber around the driver bit 35. A guide sleeve 38 is fixed to the lower end of the suction sleeve 37 so as to enclose the driver bit 35, and its tip is configured to reach inside a chuck unit 39, which will be described later.

A sensor 40 that moves together with the holding sleeve 36 is attached via a mounting plate 41, and this sensor 40 is attached to the suction sleeve 37.
It is located close to the side of the screw and is part of the screw floating detection device. Further, a dog 42 is fixed and exposed to the outside on the side near the tip of the suction sleeve 37, and this dog 42 is located corresponding to the sensor 40 and at a predetermined distance from the sensor 40. , the sensor 40 detects the movement of the dog 42 and moves the driver bit 35 and the suction sleeve 3.
It is configured to detect the amount of relative movement with respect to 7 and detect the floating of the screw.

The bracket 27a is connected to the guide sleeve 38.
The chuck unit 3 also serves as a guide, and has a pair of chuck pawls 43 at its lower end.
9 is fixed. Also, this bracket 27
a also protrudes to the rear of the fixed shaft 26,
Adjustment bolt 44 screwed into the lower end of the arm 3
It is configured to be held and fixed by two nuts 45 that are screwed together.

In the screw tightening unit described above, when the motor 33 starts rotating and the cylinder 30 is activated, the driver stand 29 is lowered. At the same time, the guide sleeve 38 descends and comes into contact with a workpiece (not shown). At this time, since the guide sleeve 38 is only pressed by the spring, the workpiece will not be damaged. When the driver stand 29 further descends from this state, the driver bit 35 moves into the guide sleeve 38.
The screw (not shown) at the tip of the guide sleeve 38 is screwed into a predetermined position on the workpiece.
At this time, in order to maintain contact between the driver bit 35 and the screw, the amount of movement of the driver stand 29 by the cylinder 30 is greater than the amount of insertion of the screw, but the pushing force of the rod 30a is configured to be small. Since the driver bit 35 is held down by the screw, it is screwed together with the screw, and the driver bit 35 is held down by the screw.
The pressing force applied to 5 will not damage the workpiece. When the screw is screwed in by a predetermined amount, the sensor 40 detects the dog 42, confirming that the screw is securely tightened. Furthermore, if the screw insertion stops midway due to some reason, the driver bit 35 and driver stand 29 also stop. Therefore, the sensor 40 that moves together with the holding sleeve 36 also stops and does not detect the dog 42 of the suction sleeve 37. This allows screw lifting to be detected.

Effects of the Invention As explained above, the present invention connects a driver stand to the rod of the cylinder, arranges the driver bit that rotates in response to the rotation of the motor to move together with this driver stand, and A sleeve is arranged to suck the screw by enclosing it, and the relative movement between the driver bit and the sleeve is detected by a sensor installed on the driver body side and a detection dog installed on the sleeve side. Also, there are advantages such as the detection dog can be easily assembled and its adjustment can be done from the outside.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of the present invention, FIG. 2 is an air control circuit diagram according to the present invention, and FIG. 3 is a sectional view of a main part of a conventional example. 3...Arm, 4...Through hole, 5...Vertical groove,
25... Screw tightening unit, 26... Fixed shaft, 27, 27a... Bracket, 28... Guide shaft, 29... Driver stand, 30... Cylinder, 30a... Rod, 31... Mounting bolt,
32...Driver body, 33...Motor, 33a
... Drive shaft, 34 ... Connection shaft, 35 ... Driver bit, 36 ... Holding sleeve, 37 ... Suction sleeve, 37a ... Suction part, 38 ... Guide sleeve, 39 ... Chuck unit, 40 ... Sensor , 41...Mounting plate, 42...Dog, 43...
Chuck claw, 44...adjustment bolt, 45...nut, 47...first supply/discharge port, 48...second supply/discharge port,
49...Pressure reducing valve, 50...Air supply source, 51...
Spring.

Claims (1)

[Claims for Utility Model Registration] A driver stand 29 is connected to the rod of the cylinder 30, and a driver bit 35 that rotates in response to the rotation of a motor 33 is attached to the driver stand 29.
At the same time, a holding sleeve 36 is fixed integrally to this driver stand 29, and a suction sleeve 37 is attached to this holding sleeve 36.
The suction sleeve 37 is urged away from the holding sleeve 36 by a spring, and the driver bit 35 is attached to the suction sleeve 37.
A guide sleeve 38 is installed to prevent the tip of the rod 30a from protruding, and a sensor is provided to detect relative movement between the guide sleeve 38 and the driver bit 35. Pressure reducing valve 4 that reduces the pressing force when descending
In the screw tightening unit to which the air supply source 50 is connected via 9, a sensor 40 is attached to the driver stand 29 so as to move together therewith, and this sensor 40 is positioned close to the side of the suction sleeve 37. , A dog 4 is provided on the side of the suction sleeve 37 that moves together with the guide sleeve 38 at a position corresponding to the sensor 40 and at a predetermined distance from the sensor 40.
2. A screw floating detection device for a screw tightening unit, characterized in that: 2 is fixed.