JPH0453522Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a rotation detection device, and in particular to a rotation detection device for a welding device having a torch rotation axis for welding a substantially circumferential joint such as a circumferential or saddle-shaped joint. It is useful as a rotation limit detection device for regulating the angle.

Prior Art When attaching a small diameter nozzle to the side surface of a cylindrical structure, a pipe member having approximately the same diameter as the through hole is fitted into a through hole provided in the cylindrical structure and welded on the circumference.

Automatic welding equipment used for such construction requires detection of the rotation limit of the welding head in order to avoid problems caused by twisting of the power supply cable, cooling water hose, shield gas hose, etc. connected to the welding head. Become.

Therefore, conventionally, for example, as shown in FIG. 9, a male threaded part 93 is provided concentrically on a rotating shaft 92 of a welding head (not shown), and a female threaded block 94 is attached to the male threaded part 93 so that it can move in the axial direction and rotate. A rotation limit detection device 91 has been proposed in which limit switches 95 and 96 are provided on both sides of the female screw block 94 in the direction of movement.

Problems with the Prior Art A rotation limit detection device 91 as shown in FIG. 9 has a problem in that the detection accuracy is poor because the female screw block 94 moves only one thread pitch per rotation of the rotating shaft 92.

Purpose of the invention The purpose of the present invention is to provide a rotation detection device that is simple in construction and handling, can be constructed at low cost, and has excellent detection accuracy.

Composition of the invention The rotation detection device of the invention has a threaded part provided on the rotating member side and a threaded part that is screwed into the threaded part on the rotating member side, and moves along the rotation center axis by rotation of the rotating member. a moving member, a detected portion provided at a predetermined portion of a screw portion on either the rotating member side or the moving member side, and the detected portion provided on the other of the rotating member side or the moving member side. The configuration is characterized in that it is equipped with a detector for detecting.

Function One of the detected part and the detection part is provided on the rotating member side, and the other is provided on the moving member side.

By the way, since the rotating member side rotates but the movable member side does not rotate, the detected part and the detection part rotate relative to each other in accordance with the rotation of the rotating shaft.

Therefore, the relative displacement of the detected part with respect to the detection part is one circumferential length of the screw for one rotation of the rotating shaft, and since this length can be made sufficiently large, high detection accuracy can be obtained.

Furthermore, it does not include any components that require advanced technology, is easy to handle, and is inexpensive.

Embodiments Hereinafter, the present invention will be explained in more detail based on embodiments shown in the figures. Here, FIG. 1 is a side view of a welding head equipped with a rotation detection device according to an embodiment of the present invention, FIG. 2 is a sectional view of essential parts of a rotation detection device according to an embodiment of the present invention, and FIG. 2 is an external view seen from below, FIG. 4 is a perspective view showing the main parts of the embodiment device shown in FIGS. 2 and 3, and FIG.
6 is a diagram equivalent to FIG. 4 of another embodiment of the present invention, FIG. 7 is a diagram equivalent to FIG. 4 of yet another embodiment of the present invention, and FIG. 7 is a diagram equivalent to FIG. FIG. 2 is a view corresponding to FIG. 2, and FIG. 8 is a sectional view taken along the line X-X' in FIG. Note that the present invention is not limited to the embodiments shown in the figures.

A welding head 1 shown in FIG. 1 is supported by a welding head support arm 2, and a motor 3 rotates a rotating shaft 4, thereby making it possible to rotate a welding torch 5 in a circumferential manner.

A rotation detecting device 11 is provided on the upper part of the rotating shaft 4, so that the rotation of the rotating shaft 4 can be detected and the limit within which the welding torch 5 can be rotated can be known.

Figures 2, 3 and 4 show the rotation detection device 1.
1 is shown in detail.

That is, a male threaded portion 12 is fixedly provided around the rotating shaft 4, and a thread 13 having a length corresponding to the rotational tolerance range of the rotating shaft 4 is provided on the male threaded portion 12.

A female screw block 14 is screwed into the male screw portion 12. A pin 15 parallel to the rotating shaft 4 passes through a part of this female threaded block 14, so when the male threaded portion 12 rotates due to the rotation of the rotating shaft 4, the female threaded block 14 does not rotate but is parallel to the rotating shaft 4. Move to.

A limit switch 16 is attached to the female screw block 14.
and 18 are provided, and their detection rollers 17 and 19 are in contact with the thread 13 of the male threaded portion 12 exposed through the opening 14 _a provided in the female threaded block 14 .

If the allowable rotation range of the welding torch 5 is 1.5 revolutions, the allowable rotation range of the rotating shaft 4 is 1.5 revolutions,
Correspondingly, the screw thread 13 is basically 1.5 rotations long, but the detection rollers 17, 1
Since the rollers 9 detect the thread 13 at different positions, an error occurs, so in order to eliminate the error, the length is actually longer than the length of 1.5 rotations by the distance between the detection rollers 17 and 19.

Both ends 13 _a and 13 _b of the thread 13 are tapered so that they can smoothly come into contact with the detection rollers 17 and 19.

Now, in the normal position of the welding torch 5, as shown in FIG.
is being detected. When the rotating shaft 4 is rotated in the direction of arrow A, the female screw block 14 moves downward,
The sensing rollers 17 and 19 slide over the thread 13 and come closer to the end _13a . Finally, the detection roller 19 of the limit switch 18
comes off the end _13a of the screw thread 13.

On the other hand, when the rotating shaft 4 is rotated as shown by arrow B, the female screw block 14 moves upward, and the screw thread 13
The end _13b of the roller approaches the detection rollers 17 and 19, and finally the end 13b comes to come off the detection roller 17.

Therefore, limit switches 16 and 18
Focusing on the detection status of both limit switches 1
The range in which 6 and 18 detect the screw thread 13 is the normal rotation range, and when the limit switch 16 detects the screw thread 13 but the limit switch 18 does not, it is the rotation limit in the direction of arrow A, and the limit switch 18 detects the screw thread 13. When the peak 13 is detected but the limit switch 16 does not detect it, it can be determined that the rotation limit in the direction of arrow B has been reached.

Therefore, the rotation limit of the rotating shaft 4 can be easily detected with high accuracy.

Note that the rotation limit can be detected even if one of the limit switches 16 or 18 is omitted and only one limit switch is used. However, in this case, it is difficult to distinguish between the ends 13 _a and 13 _b of the thread 13.

FIG. 5 shows another embodiment in which the rotation detection device 11 of the above embodiment is applied, in which the rotation of the rotation shaft 4 for rotating the welding torch is transmitted to a dummy rotation shaft 4', and then the rotation is detected. I'm starting to do it.

By doing so, the rotating shaft 4 for rotating the welding torch 5 can be shortened, which has the advantage of increasing the degree of freedom in the device layout.

FIG. 6 shows a modification of the rotation detection device 11 of the above embodiment, in which the male threaded portion 12 has a threaded thread 13 with a length corresponding to the length of the permissible rotation range of the rotating shaft 4. Instead, a male threaded portion 22 having a longer thread 23 is used. Then, screw thread missing _{portions 23 a and} 2
3 _b (not shown in the figure).

According to the rotation detecting device 21 configured in this manner, the screwing range between the male threaded portion 22 and the female threaded block 14 is widened, so there is an advantage that the movement becomes stable and smooth.

The rotation detection device 31 shown in FIG.
1, a limit switch 36 is provided on the rotating shaft 4 side.

That is, the rotating shaft 4 is provided with a male threaded portion 32, and a female threaded block 34 is provided to be screwed into the male threaded portion 32. This female screw block 34 is passed through a pin 35 and moves in the axial direction without rotating.

The thread 33 of the female screw block 34 is connected to the rotation shaft 4.
The end portions 33 _a and 33 _b are tapered so that the detection rollers 37 and 39 of the limit switches 36 and 38 come into smooth contact with each other.

The limit switches 36 and 38 are connected to the rotating shaft 4
The female screw block 34 is housed in a space 40 provided inside the female screw block 34 through the opening _32a of the male screw portion 32.
Detection rollers 37 and 39 are brought into contact with the screw threads 33 of. These limit switches 36, 38 are
It is attached to a mounting plate 41, and this mounting plate 41 rotates together with the rotating shaft 4.

Therefore, when the rotating shaft 4 rotates, the detection rollers 37 and 39 of the limit switches 36 and 38 track the thread 33 of the female screw block 34, and
When rotated to the rotation limit, the end 33 _a or 3
_3b , the rotation limit can be detected accurately and easily.

As a modification of this rotation detection device 31, the sixth
As in Embodiment 21 as shown in the figure, the length of the thread 33 provided on the female screw block 34 is longer than the length of the permissible rotation range, and missing portions of the thread are provided at both ends of the permissible rotation range. may be configured.

Further, as in the application example shown in FIG. 5, a dummy rotating shaft 4' is provided which is rotated in conjunction with the rotation of the rotating shaft 4 for rotating the welding torch 5, and the above-mentioned dummy rotating shaft 4' is provided. A rotation detection device 31 may also be configured.

If the limit switches 36, 38 are provided inside the rotating shaft 4, it becomes easy to protect the limit switches 36, 38 from adverse environments such as heat and dust.

In the above embodiment, the screw thread is removed and used as the detected portion, but a drilled hole or a recessed portion may be provided in the screw thread and used as the detected portion.

Further, although a limit switch is used as a detector, a proximity switch or the like may be used instead.

In addition, in the above embodiment, the rotation limit was simply detected by providing a detected part at a portion corresponding to the rotation limit of the rotating shaft, but in addition to this, a separate detector and a large number of detected parts were provided. The angle of rotation may also be detected.

Effects of the invention According to the invention, the invention has a threaded part provided on the rotating member side and a threaded part that is screwed into the threaded part on the rotating member side, and moves along the rotation center axis by rotation of the rotating member. a member, a detected portion provided at a predetermined portion of a screw portion on either the rotating member side or the movable member side, and a detected portion provided on the other of the rotating member side or the movable member side to detect the detected portion. A rotation detection device is provided, which is characterized by having a detector for detecting the rotation of a rotation member, thereby making it possible to easily and accurately detect the rotation of a rotating member with a simple and inexpensive configuration.

[Brief explanation of the drawing]

Fig. 1 is a side view of a welding head equipped with a rotation detection device according to an embodiment of the present invention, Fig. 2 is a cross-sectional view of essential parts of a rotation detection device according to an embodiment of the present invention, and Fig. Fig. 4 is an external view seen from below.
FIG. 5 is a view corresponding to FIG. 2 of another embodiment of the present invention, and FIG. 6 is a perspective view showing a main part of the embodiment shown in FIG. FIG. 7 is a diagram corresponding to FIG. 4 of the example, FIG. 7 is a diagram equivalent to FIG. 2 of yet another embodiment of the present invention, FIG. FIG. 2 is a sectional view of a main part of an example of a rotation limit detection device of FIG. Explanation of symbols: 1... Welding head, 4... Rotating shaft, 5... Welding torch, 11... Rotation detection device,
12...Male thread part, 13...Screw thread, 14...Female thread block, 15...Pin, 16, 18...Limit switch, 17, 19...Detection roller, 1
4 _a ...opening, 13 _a , 13 _b ...end, 21...
... Rotation detection device, 22 ... Male screw part, 23 ... Thread thread, 23 _a ... Missing part, 31 ... Rotation detection device,
32...Male thread part, 34...Female thread block, 3
3... Screw thread, 36... Limit switch, 33
_a , 33 _b ... end.

Claims (1)

[Claims for Utility Model Registration] 1. A movement that has a threaded portion provided on a rotating member side and a threaded portion that is threadedly engaged with the threaded portion on the rotating member side, and moves along a central axis of rotation as the rotating member rotates. a member; a detected portion provided at a predetermined portion of a screw portion on either the rotating member side or the movable member side; and a detected portion provided on the other of the rotating member side or the movable member side to detect the detected portion. A rotation detection device characterized by comprising a detector for detecting rotation. 2. The rotation detection device according to claim 1, wherein the rotating member is a rotating shaft. 3. The threaded part on the rotating shaft side is a male threaded part having a thread length corresponding to the rotational tolerance range of the rotating shaft, and the movable member has a female threaded part that screws into the male threaded part. The block is a female thread block that moves along the rotation axis without rotating due to the rotation of the rotation shaft, the detected portions are both ends of the thread, and a detector is provided on the female thread block and detects the ends of the thread. 2. The rotation detection device according to claim 2, which is a limit switch for detecting. 4. The threaded part on the rotating shaft side is a male threaded part having a length longer than the allowable rotation of the rotating shaft, and the movable member has a female threaded part that screws into the male threaded part, and the moving member has a female threaded part that screws into the male threaded part. It is a female screw block that moves along the rotation axis without rotating due to the rotation of the shaft, and the detected member is a missing part of the screw thread provided at both ends of the length of the screw thread that is allowed to rotate. 3. The rotation detecting device according to claim 2, wherein the rotation detecting device is a limit switch provided on the female thread block and detecting a missing portion of the thread. 5. The threaded part on the rotating shaft side is a male threaded part, and the movable member has a female threaded part that has a thread length corresponding to the rotational tolerance range of the rotating shaft and is screwed into the male threaded part. The block is a female screw block that moves along the rotation axis without rotating due to the rotation of the rotation shaft, the detected portions are both ends of the screw thread of the female screw block, and a detector is provided on the male screw portion side. The rotation detection device according to claim 2, which is a limit switch that detects the end of the thread of the female screw portion. 6. The threaded part on the rotating shaft side is a male threaded part, and the movable member has a female threaded part that has a thread length longer than the permissible rotation range of the rotating shaft and is screwed into the male threaded part. This is a female screw block that moves along the rotation axis without rotating due to the rotation of the shaft, and the detected part is a missing screw thread provided at both ends of the female screw part with a length corresponding to the allowable rotation range of the screw thread. 3. The rotation detection device according to claim 2, wherein the detector is a limit switch provided on the male threaded portion side and detects a missing thread of the female threaded portion.