JPH0750414B2 - Stroke end detection device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stroke end detection device for a rotating body such as a rotating arm of an industrial robot, and a dock is directly fixed to the rotating arm. Switch ON /
By turning off and turning on / off the second switch via the switching lever, a small stroke end detection device for a rotating body is obtained.

<Prior Art> As a stroke end detecting device for detecting a stroke end of a rotary arm of an industrial robot, there is a conventional one as follows.

This device is a device for detecting the stroke end when the rotation stroke of the rotary arm exceeds one rotation.

As shown in FIG. 6, the stroke end detection device in this case is the drive gear 1 fixed to the rotary shaft of the rotary arm.
And a driven gear 2 meshed with the drive gear 1. Reference numeral 3 denotes a drive motor that rotationally drives this rotary shaft, and its ON / OFF is controlled by the detection circuit 4.

In this case, since the stroke end corresponding to two rotations of the rotary shaft (rotary arm) is detected, the radius of the drive gear 1 is R ₁
Then, that of the driven gear 2 is R ₂ (R ₂ ≧ 2R ₁ ). That is, when the drive gear 1 makes two revolutions, the driven gear 2 makes one revolution. Then, by detecting the rotational position of the driven gear 2 in one rotation with the limit switches 5 and 6,
The stroke end of the rotation stroke (two rotations) of the rotary arm is detected.

When this stroke end is detected, the detection circuit 4 stops the driving of the drive motor 2 and controls it to perform the next operation.

Here, the limit switches 5 and 6 are arranged along the circumference of the driven gear 2 so as to face each other, and are turned on by being fixed to the driven gear 2 and contacting a projecting dock 7.
Becomes The limit switch 5 has the driven gear 2 in the forward direction 1
When the driven gear 2 makes one rotation in the opposite direction (360 degrees in the arrow Y direction in the figure), the switch 6 is turned on when the rotation (rotation by 360 degrees in the arrow X direction in the figure) occurs. . Then, the detection circuit 4 detects the stroke end of the rotary arm when one of the switches 5 and 6 is turned on,
In this configuration, the driving of the drive motor is stopped.

<Problems to be Solved by the Invention> However, in such a conventional stroke end detection device for a rotating body, when detecting the stroke end of the rotation stroke corresponding to two rotations of the rotating body,
A driven gear having a radius equal to or more than twice the radius of the driving gear is meshed with the driving gear, and a limit switch for detecting the stroke end is provided on the driven gear.

As a result, it is necessary to secure a mounting location for a large driven gear, which deteriorates the mountability and causes an increase in the size of the stroke end detection device of the rotating body.

Then, the objective of this invention is providing the stroke end detection apparatus of the rotary body which can be mounted in a small space.

<Means for Solving the Problem> The present invention is directed to a rotating body that rotates in both forward and reverse directions, a protrusion attached to the rotating body, and a protrusion that is disposed along the circumference of the rotating body so as to be spaced apart from each other. The pair of first switches with which the projecting pieces abut, and the pair of first switches are interposed between the pair of first switches.
A switching lever that is switched between a switch ON position and a switch OFF position when the projecting piece abuts, and a second switch that is turned ON / OFF by this switching lever;
A stroke end detection device for a rotary body, comprising: a determination unit that detects that the rotary body has reached the stroke end based on output signals from the first and second switches.

<Operation> In the stroke end detection device for a rotating body according to the present invention, when the rotating body rotates, the protrusion sequentially operates the first switch.
When the switch is turned on, the switch lever is switched between the switch on position and the switch off position. This switching lever turns the second switch on and off.

Then, the detection of the stroke end of the rotating body is performed by this first
The determination means performs the combination of the output of the switch and the output of the second switch. For example, the first switch detects the rotation direction and the rotation position of the rotating body, and the second switch detects the rotation speed of the rotating body.

As a result, in order to detect the stroke end corresponding to two rotations of the rotating body, for example, by the second switch, 1
The stroke end is detected in the state of the first switch by detecting the second rotation or the second rotation.

<Embodiment> An embodiment of a stroke end detection device for a rotating body according to the present invention will be described below with reference to the drawings.

FIG. 1 is a conceptual diagram showing a main part of a stroke end detection device for a rotating body according to an embodiment of the present invention.

In this figure, reference numeral 21 denotes a disk (rotating body) attached to a rotary shaft 22 of a rotary arm of an industrial robot, for example. The rotary shaft 22 is driven and rotated by a drive motor 23, and therefore the disk 21 rotates in the arrow L or R direction in the figure.

A dock (projection piece) 24 is projectingly provided on the outer peripheral portion of the disc 21. The dock 24 is a plate or a ridge, and the tip of the dock 24 projects outward from the outer peripheral edge of the disc 21 by a predetermined length.
Is stuck to.

The limit switches 25 and 26 for detecting the rotational position of the disc 21 are arranged along the outer periphery of the disc 21 at a predetermined distance. These limit switches 25 and 26 are mounted at positions close to the disk 21 so that the dock 24 contacts the disk 21 when the disk 21 is rotated.

Further, the limit switches 25 and 26 are arranged at positions separated from each other by a predetermined angle (for example, ± 30 degrees). Therefore, these limit switches 25 and 26 are separated from the center of rotation of the disk 21 by an interval of 60 degrees.
It is located outside the circumference of.

The positions where the limit switches 25 and 26 are arranged correspond to the stroke end of the rotation stroke of the rotary shaft 22 (the position where the rotary shaft 22 rotates 330 degrees with respect to the reference position).

Therefore, the limit switch 25 detects the stroke end position of the circular plate 21 in the clockwise direction in the figure (the arrow R direction in the figure). The limit switch 26 is a disk
It is possible to detect the stroke end position in the counterclockwise direction (the direction of the arrow L in the figure) of 21.

It should be noted that these limit switches 25 and 26 both use B contacts, as shown in FIG.

Further, 27 is a switching lever which is a substantially V-shaped member, and is provided so as to be swingable by being biased by a spring 27a with a pin 28 penetrating the bent portion as a fulcrum.

This switching lever 27, as shown in FIG.
Are arranged in proximity to the outer periphery of and corresponding to the reference position. The switching lever 27 is arranged at an intermediate position between the limit switches 25 and 26.

The switching lever 27 is biased by a spring 27a and is configured to reciprocate between the solid line position and the broken line position shown in the drawing (swing about the pin 28 as a fulcrum) by contacting the dock 24.

For example, when the disk 21 rotates in the direction of the arrow R in the drawing, the switching lever 27 contacts the dock 24 and swings from the solid line position in the drawing to the broken line position in the drawing, and is biased by the spring 27a to the broken line position. Retained.

On the other hand, when the disk 21 reversely rotates in the direction of the arrow L in the drawing and the dock 24 comes into contact with the switching lever 27 from the reverse direction, the switching lever 27 swings from the broken line position in the drawing to the solid line position in the drawing. .

That is, the switching lever 27 is switched between two positions by the dock 24.

Then, in the vicinity of this switching lever 27, the limit switch
29, 30 are provided. The limit switch 29 is arranged to be turned on when the switching lever 27 is in the solid line position shown, and the limit switch 230 is arranged to be turned on when the switching lever 27 is in the broken line position. As shown in FIG. 2, these limit switches 29, 30 have normally open contacts (A
Contact point).

The decision circuit 31 uses these limit switches 25, 26 and 2
The fact that the disc 21 has reached the stroke end is detected based on the respective output signals from 9,30. Then, when the determination circuit 31 detects this stroke end,
The drive of the drive motor 23 is stopped, the brake is applied, and the next command is output.

Specifically, as shown in FIGS. 2 (A) and 2 (B), the determination circuit 31 includes a limit switch 25 and a limit switch 29.
And a circuit in which the limit switch 25 and the limit switch 29 are connected in parallel. The terminal 32 of this parallel circuit (FIG. 2 (A)) is connected to the power supply for the drive motor 23, and the terminal 33 is connected to the forward rotation switch (plus side) of the drive motor 23. Also,
The terminal 34 of the parallel circuit (FIG. 2 (B)) is also used as a driving power source, and the terminal 35 is used as a motor reverse switch (minus side).
Each is connected.

Therefore, when the disc 21 is rotating in the direction of arrow R in FIG. 1, the limit switch 27 is OFF and the limit switch 2
When 5 is turned on, the rotation of the drive motor 23 stops. Also,
When the disk 21 is rotating in the direction of the arrow L in FIG. 1, when the limit switch 30 is OFF and the limit switch 26 is ON, the drive motor 23 stops rotating.

Further, in the determination circuit 31, the B-contact limit switches 25 and 26 and the A-contact limit switches 29 and 30 are connected in parallel. Therefore, even if the limit switches 29, 30 do not operate due to a malfunction of the switching lever 27, the drive motor 23 is always driven at the stroke end position of the disc 21 when the limit switches 25, 26 operate. Yes (has a fail-safe function).

Next, the operation of this embodiment will be described with reference to FIG.

FIG. 3 is a timing chart showing ON / OFF states of the respective switches 25, 26, 29, 30 corresponding to the rotation angle position of the dock 24 in the stroke end detection device for a rotating body according to the embodiment of the present invention. It is a chart.

The vertical axis of this timing chart is ON / OFF of each switch
The horizontal axis indicates the relative rotation angle of the dock 24.

This timing chart shows the case where the disk 21 rotates in the direction of arrow R in FIG.

When the disk 21 starts to rotate in the R direction, the dock 24 starts rotating from the effective stroke side from the stroke end position where the limit switch 26 is turned off. In this state, the selector lever 27 is in the solid line position and the limit switch 30 is in the O position.
N, limit switch 29 is OFF.

From this state, the disc 21 starts the first rotation.

When the disk 21 rotates up to 330 degrees (at the end of the first rotation),
The dock 24 pressurizes the limit switch 25 for a certain period of time. Only during this pressing, the limit switch 25 is turned off.

Further, when the disk 21 rotates and the dock 24 reaches the 360 degree position (immediately before the second rotation), the dock 24 contacts the switching lever 27 and tilts it. As a result, the switching lever 27 is swung to the position shown by the broken line and switched. Therefore,
Limit switch 29 is turned on. At the same time, the limit switch 30 is turned off.

Further, when the disk 21 rotates and the dock 24 reaches the 390 degree position, the limit switch 26 is brought into contact with the dock 24 and turned off only during that time.

Then, the disk 21 rotates further and the dock 24 is placed at the 690 degree position.
When comes, the limit switch 25 is turned off for the second time. At this time, the determination circuit 31 shown in FIG. 2 (A) determines that the limit switches 25 and 30 have both turned off, and that the stroke end position of the effective stroke S has been reached, so that the drive motor 23 is de-energized and the drive motor 23 is driven. The driving of the motor 23 stops.

The disc 21 is braked by the electromagnetic brake.

That is, the stroke end of the disc 21 is detected, and its overstroke is prevented.

In the above embodiment, the limit switches 29,30
Although the normally open contact (A contact) was used in Fig. 4, (A),
As shown in (B), normally closed contact (B contact) limit switches 41, 42 may be used.

4 (A), (B) and FIG. 5 show another embodiment of the present invention.

In this case, as shown in FIG. 5, the determination circuit 31 shuts off the energization of the drive motor 23 when both the limit switches 41 and 26 are turned off. That is, the stroke end (rotational position of 690 degrees) of the disc 21 is detected by these limit switches 41 and 26.

Other configurations and operations are similar to those of the above embodiment.

Further, in the present invention, in addition to the above-described embodiment, for example, the rotation stroke of the rotating body may be three rotations (1050 degrees) or more, and the stroke end thereof may be detected. That is, the stroke end can be detected by connecting the switch for detecting the rotation speed of the rotating body and the switch for detecting the rotation position in parallel and interposing the switch in the power supply line to the drive motor. .
That is, it is possible to reliably prevent the overstroke of the rotating body having a stroke of two or more rotations with a simple configuration.

<Effects of the Invention> As described above, according to the stroke end detection device for a rotating body of the present invention, only the mounting positions of the switching lever and the switch need to be secured in the vicinity of the rotating body, so that the device can be downsized. In addition, it is possible to improve the mountability.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a stroke end detection device for a rotating body according to an embodiment of the present invention, and FIGS. 2A and 2B are stroke end detection devices for a rotating body according to an embodiment of the present invention. Limit switch connection circuit diagram, FIG. 3 is a timing chart showing the operation of the rotary body stroke end detection apparatus according to one embodiment of the present invention, and FIGS. 4 (A) and 4 (B) are other embodiments of the present invention. FIG. 5 is a timing diagram showing the operation of a limit switch connection circuit of a rotary body stroke end detection device according to an example, FIG. 5 is a timing chart showing the operation of a rotary body stroke end detection device according to another embodiment of the present invention, and FIG. It is a conceptual diagram which shows the stroke end detection apparatus of a rotary body. 21 ... Disc (rotating body), 22 ... Rotating shaft, 23 ... Drive motor, 24 ... Dock (projection piece), 25, 26 ... Limit switch (first switch), 27 ... Switching lever , 29, 30 ... Limit switch (second switch), 31 ... Judgment circuit (judgment means).

 ─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-57-48444 (JP, A) JP-A-2-61456 (JP, A) JP-A-62-19915 (JP, A) Actual development Sho-55- 11561 (JP, U) Actually opened 50-56898 (JP, U) Actually opened 61-16613 (JP, U)

Claims (1)

[Claims] Claim: What is claimed is: 1. A rotating body that rotates in both forward and reverse directions, a protrusion attached to the rotating body, and a pair of protrusions that are arranged apart from each other along the circumference of the rotating body and are in contact with each other. A switching lever that is interposed between the first switch and the pair of first switches and that is switched between a switch ON position and a switch OFF position by contacting the projecting piece, and the switching lever. A second switch that is turned on and off by a switch, and a determination unit that detects that the rotating body has reached the stroke end based on the output signals from the first and second switches. Characteristic rotary end detection device for rotating body.