JPH0429949Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention has a
This invention relates to a bit alignment device for a suction type screw tightening machine in which a tightening rod having a bit at its tip for rotating a screw to be tightened is rotatably and slidably inserted.

``Prior Art'' A suction type screw tightening machine is already known, and FIG. 3 is a perspective view of an example of the screw tightening machine. In this figure, 1 is the machine body, 2 is a hopper that accommodates machine screws, etc. attached to the machine body 1, and a scoop plate 3 that moves up and down sends the machine screws, etc. in the hopper 2 to the chute 4 with directionality. It is configured as follows.

7 is an air cylinder attached to the body 1, which moves the motor 9 up and down via the holder 8. 1
0 is a support pipe attached to the lower part of the holder 8.

In FIG. 4, which shows an enlarged view of the portion from the support pipe 10 to the catcher 6, 11 is an intake pipe whose upper end is slidably inserted into the support pipe 10, and 12 is a cap with the upper end of the intake pipe 11 closed. This is locked to the lower end of the support pipe 10 so that the intake pipe 11 cannot be separated from the support pipe 10, and the intake pipe 11 is biased downward by a spring 13 via the cap 12.

The upper end of 16 is connected to the shaft of motor 9,
It is a tightening rod that is inserted into the intake pipe 11 through the cap 12 and has a tightening bit 15 such as a machine screw attached to its lower end.

17 is a small diameter portion provided on the intake pipe 11 to support the bit 15 (see Fig. 5); 18 is a flat portion provided on the bit 15 in a portion facing the small diameter portion 17; allows for ventilation.

Reference numeral 19 denotes a suction pipe connected to the suction pipe 11, which is connected to a suction pump (not shown), etc., to suck the air inside the suction pipe 11, and attract the screw to be tightened to the tip of the bit 15. It is configured as follows.

20 is a stopper fixed to the intake pipe 11;
Reference numeral 21 denotes a support plate whose one end is fixed to the machine body 1, and a catcher 6 is provided at the bottom of the support plate for supporting machine screws, etc. sent through the chute 4 one by one. An intake pipe 11 is slidably inserted. 23 is work,
24 is a screw hole, and 25 is a machine screw.

In FIG. 3, a slide shaft 26 is fixed to the lower surface of the holder 8, and a stopper 27 provided on the outer periphery of the slide shaft comes into contact with the body 1 to stop the bit 15 from descending.

Tightening of the machine screw 25 by this device begins with the scoop plate 3 feeding the machine screw 25 in the hopper to the chute 4 as shown in FIG. The machine screws 25 mounted on the chute 4 are oriented in a predetermined direction at the intermediate portion of the chute 4 and supported one by one by a catcher 6.

The machine screw 25 supported by the catcher 6 enters the intake pipe 11 by the intake air, and the head of the machine screw 25 is attracted to the tip of the bit 15 by the negative pressure of the intake pipe. Then, due to the operation of the air cylinder 7, the intake pipe 11 is lowered together with the motor 9, etc.
The lower end contacts the screw hole 24 of the workpiece 23 at a position overlapping with the screw hole 24 of the workpiece 23 . Further, when the motor 9 and the like are lowered, the intake pipe 11 is inserted into the support pipe 10, thereby compressing the spring 13.

On the other hand, the machine screw 25 set in the bit 15 is in contact with the mouth of the screw hole 24 of the workpiece 23, and the motor 9 is activated to rotate the tightening rod 16 and screw the machine screw 25 into the screw hole 24. be. When the screws 25 are tightened, the motor 9, intake pipe 11, etc. are returned to their original positions repeatedly.

"Problem that the invention aims to solve" The conventional screw tightening machine is constructed as described above, and the difference in diameter between the support hole 22 of the support plate 21 and the intake pipe 11 causes the intake pipe 11 to move slightly in the radial direction. making it possible to do so. In addition, due to the difference in diameter between the small diameter portion 17 of the intake pipe 11 and the diameter of the bit 15, the intake pipe 11
This allows the bit 15 to move in its radial direction. This is the axis of bit 15 and work 2
When a deviation occurs in the axis of the screw hole 24 of No. 3, the deviation is absorbed.

However, since the intake pipe 11 moves freely with respect to the support hole 22 and the bit 15 moves freely within the small diameter portion 17 of the intake pipe 11, the bit 1
If the bit 15 is not held as close to a predetermined axial center position as possible, there is a problem in that the positioning accuracy when aligning the axes of the bit 15 and the screw hole 24 of the workpiece 23 will be lowered.

Furthermore, when installing the intake pipe 11 in a computer-controlled industrial robot and teaching it the screw tightening position, the position of the bit 15 is not fixed, so the positioning accuracy during teaching and driving becomes low. There are also problems.

``Purpose of the invention'' This invention improves the positioning accuracy when aligning the bit with the axis of the screw hole by aligning the intake pipe or bit so that it is in the fixed position as much as possible when no external force is acting on it. It is an object of the present invention to provide a screw tightening device which can improve the detection accuracy of the bit position during teaching and driving when mounted on a robot.

``Means for Solving the Problems'' In order to achieve the above objective, the main means adopted by the present invention is that a bit is provided at the tip of the intake pipe that slides in the axial direction. In a screw tightening machine in which a tightening rod is rotatably and slidably housed, a floating shaft consisting of an intake pipe or a tightening rod and a cylindrical pressurizing body are fitted in a relatively slidable manner, and A guide member is fixed to the screw tightening machine main body or the intake pipe facing the pressurizing body, a conical tapered surface is formed on the opposing portion of the pressurizing body or the guide member, and the pressurizing body or This is a bit alignment device for a screw tightening machine which presses and urges the guide members together.

Among the above components, the conical tapered surface provided on at least one of each pressure body and each guide member may be inclined in any direction of the axis of the intake pipe, and is compatible with the tapered surface. The contacting end portion may be in contact with substantially the entire surface of the tapered surface, or may be in contact with a portion of the tapered surface.

"Operation" In the suction pipe of the screw tightening machine of the present invention and the tightening rod inserted therein, the pressurizing body and the guide member are pressed against each other, so an external force in a direction perpendicular to the axis is applied to them. When not, the floating shaft is biased toward the guide member in the axial direction by the centripetal action of the tapered surface. When a perpendicular external force is applied to the floating shaft, the pressurizing body can shift relative to the guide member, and the floating shafts such as the intake pipe and tightening rod can move somewhat accordingly. If the axes of the screw hole in the workpiece and the tightening rod do not match, one or both of the tightening rod and intake pipe will shift accordingly, absorbing the decrease in positioning accuracy and allowing screws, etc., to be screwed into the screw hole. can. When screwing in a machine screw, etc. is finished, and the intake pipe and tightening rod are released from the workpiece and machine screw, etc., the intake pipe and tightening rod return to their original coaxial position due to the centripetal action of the tapered surface. do.

"Embodiments" Hereinafter, embodiments embodying the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention.

Here, FIG. 1 is a sectional view showing the main parts of a screw tightening device according to one embodiment of the present invention, and FIG. 2 is a sectional view showing the main parts of another embodiment.

It should be noted that the following example is only a specific example of the present invention, and is not intended to limit the technical scope of the present invention.

In FIG. 1, reference numeral 11 denotes an intake pipe which is an example of a floating shaft, and one end of which is slidably inserted into a support hole 22 of a support plate 21 fixed to the body 1 of FIG. 3. A tightening rod 16 is an example of a floating shaft slidably inserted into the intake pipe 11, and a bit 15 is attached to the tip thereof.

Reference numeral 30 denotes a ring-shaped guide member fixed to the support plate 21 around the support hole 22, the surface of which is a conical tapered surface 3 centered on the intake pipe 11.
It's becoming 1. Reference numeral 32 denotes a cylindrical pressurizing body which is disposed opposite to the tapered surface 31 and into which the intake pipe 11 is inserted. A plurality of balls 36 are interposed between the tapered surface 31 and a ring-shaped recess 35 provided on the surface of the cylindrical body 33 facing the cylindrical body 31 . 37 is pressurizing body 3
2 toward the tapered surface 31, one end of which is locked to the cylindrical body 33, and the other end supported by a cover 38 fixed to the support plate 21.

Reference numeral 39 denotes a stepped guide member formed by reducing a portion of the inner diameter of the intake pipe 11, and its axial surface forms a conical tapered surface 40. 41
is a pipe-shaped pressurizing body which is disposed in contact with the tapered surface 40 and into which the tightening rod 16 is slidably inserted; 43 and a plurality of balls 44 as ventilation protrusions interposed between the cylindrical body 42 and the tapered surface 40, and is biased toward the tapered surface 40 by a coiled spring 45.

In the screw tightening device configured as described above, when the air in the intake pipe 11 is sucked from the piping 19, the air on the tip side of the bit 15 passes between the plurality of balls 44 forming the pressurizing body 41. Since it flows, the tip of the bit 15 also becomes negative pressure.
Picks up machine screws.

Pipe-shaped pressurizing bodies 32 and 41 arranged on the outer peripheries of the intake pipe 11 and the tightening rod 16 are connected to guide members 30 and 39 fixedly provided on the support plate 21 and the inner periphery of the intake pipe 11, respectively. It is pressed against the tapered surfaces 31 and 40 by springs 37 and 45.

Therefore, when the intake pipe 11 is raised together with the motor 9 and no external force is acting on the intake pipe 11 and the tightening rod 16 as shown in FIG. Since the guide members 30, 39 are pressed against the tapered surfaces 31, 40 with equal force, the balls 36, 44 forming a part of the pressurizing bodies 32, 41 are pressed against the tapered surfaces 31, 40 of the guide members 30, 39.
The intake pipe 11 is located at approximately the same distance from the center of the support hole 22, and the intake pipe 11 is located approximately at the center of the support hole 22.
The tightening rods 16 are each located approximately in the center of the intake pipe 11. That is, both are aligned to a predetermined center position.

Moreover, the forces of springs 37 and 45 act on the suction pipe 11 and the tightening rod 16, respectively, so that they do not move from the above-mentioned positions. If placed in the matching position, the axis of the bit 15 can always be aligned with the axis of the screw hole 24, and the machine screw 25 can be screwed into the screw hole 24 reliably.

When the axes of the bit 15 and the screw hole 24 are misaligned, both or one of the intake pipe 11 and the tightening rod 16 is compressed by the spring 37 via the respective pressure bodies 32 and 41 depending on the eccentric direction. ，
45 is compressed and moves in the radial direction, it is possible to screw the machine screw 25 into the screw hole 24 whose axis is misaligned.

In this way, the intake pipe 11 and the tightening rod 1
Even if both or one of the screws 6 move in the radial direction, if they separate from the workpiece 23 and the machine screw 25,
The compressed springs 37, 45 use their reaction force to return the pressurizing bodies 32, 41 to the center position of each tapered surface 31, 40 and maintain that state.
If the position of the workpiece 23 is determined accurately, it is possible to always align the axes of the screw 24 and the bit 15.

The ball 36 in the above embodiment is a ring, etc.
Any material that can smoothly move in contact with the tapered surface 31 can be used. And the pressurizing body 32
As shown in FIG. 2, except for the ball 36 in FIG. It is appropriate to do so. However, surface contact is also possible.
Coating the contacting surfaces of the pressurizing body 32 and the guide member 30 with fluororesin is also suitable for smoothing the movement of the pressurizing body 32.

The pressure body 41 of the tightening rod 16 can also be constructed as shown in FIG. Pressure body 41
Although the air gap between the balls 44 is utilized for the ventilation in the portion shown in FIG. The tapered surfaces 31 and 40 can also be inclined in the opposite direction to that shown in FIG. 1, that is, in the direction toward the tip of the bit 15. Then, the tapered surface 31,
40 can also be formed on the pressurizing bodies 32 and 41.

Although the above embodiment has been described with reference to an application to an industrial robot, it is also applicable to an application in which screws are tightened in a fixed position. When applied to a robot, since the positions of the intake pipe 11 and the tightening rod 16 are fixed, the position detection accuracy during teaching can be increased, and accurate screw tightening work can be performed.

``Effect of the invention'' As described above, the present invention provides a screw tightening machine in which a tightening rod with a bit at the tip is rotatably and slidably housed in an intake pipe that slides in the axial direction. A floating shaft consisting of an intake pipe or a tightening rod and a cylindrical pressure body are fitted so as to be able to slide relative to each other, and a guide member is fixed to the screw tightening machine body or the intake pipe opposite to the pressure body. A bit of a screw tightening machine, characterized in that a conical tapered surface is formed on opposing portions of the pressure body or the guide member, and the pressure body or the guide member is biased to press against each other. Since it is an alignment device,
The intake pipe as a floating shaft is aligned with the support plate as a guide member, or the tightening rod as a floating shaft is aligned with the intake pipe as a guide member, and the respective taper surfaces are aligned. The core action allows swing shafts such as intake pipes and tightening rods to maintain their fixed positions. Therefore, the positioning accuracy when aligning the axes of the bit and the screw hole is improved, and screw tightening can be performed relatively efficiently and accurately. In this case, the positioning accuracy can be further improved by providing alignment properties to the intake pipe and the tightening rod. When this screw tightening device is applied to a robot, the position of the bit can be easily detected.
It is possible to increase the accuracy and perform more accurate screw tightening.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the main parts of a screw tightening device according to one embodiment of the present invention, FIG. 2 is a cross-sectional view showing the main parts of another embodiment, and FIG. 3 is a perspective view of the screw fastening device.
FIG. 4 is a sectional view showing essential parts of a conventional screw tightening device, and FIG. 5 is an enlarged sectional view taken along line A--A in FIG. 4. Explanation of symbols, 11...Intake pipe, 15...Bit, 16...Tightening rod, 21...Support plate,
22... Support hole, 30... Guide portion, 31... Tapered surface, 32... Pressure body, 37... Spring, 39...
...Guide portion, 40... Tapered surface, 41... Pressure body, 45... Spring.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) In a screw tightening machine in which a tightening rod with a bit at the tip is rotatably and slidably accommodated in an intake pipe that slides in the axial direction, an intake pipe Alternatively, a cylindrical pressurizing body is slidably fitted onto a floating shaft made of a tightening rod via a bearing member, and a guide member is fixed to the screw tightening machine body or the intake pipe opposite to the pressurizing body. A bit adjustment for a screw tightening machine, characterized in that a conical tapered surface is formed on opposing portions of the pressure body or the guide member, and the pressure body or the guide member is biased to press against each other. Core device. (2) The bit alignment device according to claim 1, wherein the pressurizing body is urged to press against the conical tapered surface via a ball.