JPS6029028B2 - Shaft overload detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device configured to detect an overload condition in a power transmission system via a slip clutch and stop a drive source.

In the transmission parts of mechanical devices that are relatively large and have complex structures, a slip clutch is inserted as a safety device to prevent the device from being destroyed in the event of an overload. The system detects this and stops the drive source.

However, in the conventional detection means, when re-driving a drive device that has been automatically stopped due to overload detection, it is difficult to restore the drive device to the state before the stoppage. In addition, in the method of monitoring the time required for one rotation of the spindle using a timer or the like and detecting overload from the delay in rotation, overload cannot be detected while the spindle rotates once, and at the same time, whenever the rotation speed of the spindle is changed, There was an inconvenience in that the monitoring timer had to be changed. Furthermore, Jikko Floor 49-4133
As shown in Publication No. 1, this device detects the relative rotation of two gears, but this device makes the currents generated by two generator coils associated with the two gears in phase. Therefore, once one of the gears has stopped due to overload, there is a problem in that in order to restart it, readjustment is required so that the currents are in the same phase.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shaft overload detection device that has a simple structure and is easy to use without requiring adjustment even when restarting after once detecting an overload condition.

The present invention provides a shaft overload detection device provided in a transmission mechanism that transmits rotation of an output shaft to a driven shaft by a pair of gears interposed with a slipping clutch, in which a large number of small holes are formed at a pitch corresponding to the number of teeth of the gears. A rotary disk having a hole in the peripheral edge thereof is attached to each of the output shaft and the driven shaft, and the rotating disk cooperates with the hole 4 of the disk to detect the rotation of the disk and generate a signal. A small hole detection device capable of transmitting a signal is provided, and the small hole detection device corresponding to the rotating disk attached to the output shaft is connected to each input terminal of the plurality of counters so that a detection signal can be inputted to the input terminal, The small hole detection device corresponding to the rotating disk attached to the driven shaft is connected to the reset terminal of the plurality of counters, and the detection signal is configured to be input to the set terminal.

An embodiment of the present invention will be described below with reference to the drawings.

The rotation of the output shaft 3 driven by the motor 1 and the reducer 2 is transmitted to the main shaft 7, which is a driven shaft, by a pair of meshing gears 5 and 6. A slip clutch 4 is interposed between them.

That is, the clutch portion 40 of the slip clutch 4 and the output shaft 3 are integrally fixed, and the gear 5 rotatably engaged with the clutch member is driven by a friction plate 41 with a spring 42. They are compressed and integrated as a slip clutch to rotate. Therefore, under normal conditions, the gear 5 and the output ball 3 rotate as one,
Rotation is transmitted to the main shaft 7 via the gear 6, but when an overload occurs on the main shaft 7 side, slip occurs between the gear 5 and the friction plate 41, and the gear 5 transfers the rotation of the output shaft 3 to the main shaft. It is designed not to be transmitted to the other side. A rotary disk 8 is fixed to the output shaft 3 so that it can rotate together with the output shaft.

This rotary disk 8 has a large number of small holes 81 bored at equal intervals along its periphery, and is also provided with a transmission type photoelectric switch 9 that detects the light beam passing through the small holes and outputs it as a signal. put. Apart from this, the main shaft 7 is also similarly provided with a rotating disk 10 having small holes 101 arranged therein and a photoelectric switch 11, so that the rotation of the main shaft 7 can be detected.
Small holes 81 and 101 in the disks 8 and 101
The pitch is set to correspond to the ratio of the number of teeth of gears 5 and 6. The outputs of the photoelectric switches 9 and 11 are:
As shown in FIG. 2, the counters are introduced into a set of two counters C, , C2.

Each of these counters is equipped with an input terminal S and an IJ set terminal R, and when a signal is input to the input terminal S of the counter, it is counted and progressive, and when a signal is input to the reset terminal R, it is counted. The count is cleared and becomes zero. Furthermore, when the counts of the counters C, C2 progress to 1, 2, and reach 2, a signal for stopping the motor can be sent out. In the configuration of this device, the output of the output shaft side photoelectric switch 9 can be inputted to the input terminal S of each counter, and the output of the main shaft side photoelectric switch 11 can be inputted to the reset terminal R of each counter. I'll keep it. However, the photoelectric switch 11 has a positive contact output and a reverse contact output, which will be described later, and the positive contact output 11a is sent to the first counter C,
The reverse bushing point output 11b is made to be introduced into the second counter C2. Next, the operation of this device will be explained.

In a normal operating state where no overload is acting on the main shaft 7, the rotation of the output shaft 3 is transmitted to the main shaft 7 via the gears 5 and 6, and at this time the two photoelectric switches 9 and 1 are activated.
1 detects the movement of the small hole and outputs the same number of signals shifted by a slight time t' as shown in FIG. 3A.
Looking now at the counter C in FIG. 1, even though the output shaft side photoelectric switch 9 inputs to the input terminal S, the reset input of the main shaft side photoelectric switch 11 is introduced, so the count is progressive. Therefore, no stop command is issued to the motor 1. However, if an overload is applied to the main shaft 7, the slip clutch 4 is activated, and the gear 5 begins to slip, the rotating disk 10 will no longer rotate normally, and the photoelectric switch 11 will not operate as shown in FIG. As shown, a normal signal (dotted line) cannot be obtained.

Therefore, the counter C receives only an input signal and is not reset, so that the count progresses and a stop signal is issued to the motor. On the other hand, when the main shaft 7 is stopped due to an overload, it may stop at a position where the small hole 101 of the rotating disk 10 and the photoelectric switch 11 are aligned. 3rd as reverse contact output 11b
It emits a signal as shown in Figure '.

Since this signal is not reset in the second counter C2, only the input of the output shaft side photoelectric switch 9 is counted, and therefore the count is progressive and a stop signal is issued to the motor 1. In the present invention, since it is necessary that the gear 6 on the driven shaft side and the rotating disk 10 are integrated, the rotating disk is not configured as a disk, and the gear 6' as shown in FIG.
Alternatively, the disk 10' may be directly fixed to the disk 10'.

It is also possible to use a proximity switch instead of a photoelectric switch. According to the device of the present invention, it is extremely easy to handle because it does not require any adjustment or operation when restarting operation after detecting an overload and automatically stopping. It is effective and convenient.

[Brief explanation of the drawing]

FIG. 1 is a structural explanatory diagram showing the main part configuration of the shaft overload detection device according to the present invention. Figure 2 is a schematic wiring diagram of the signal system. Figure 3 shows the waveform of the detection signal. FIG. 4 is a partial view of another embodiment of the device of the present invention. 1...
...Motor, 2...Reducer, 3...Output shaft,
4...Slip clutch, 5, 6...Gear, 7...Main shaft (
Driven shaft), 8, 10...Rotating disk, 9, 11
...Photoelectric switch, C,,C2...Counter. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. In a shaft overload detection device installed in a transmission mechanism that transmits rotation of an output shaft to a driven shaft by a pair of gears with a sliding clutch interposed, a large number of small Rotating disks with holes drilled in their peripheries are attached to the output shaft and the driven shaft, respectively, and the rotation of the disks is detected by working with the small holes of the respective rotating disks to generate a signal. A small hole detection device capable of transmitting a signal is provided, and the small hole detection device corresponding to the rotary disk attached to the output shaft is connected to each input terminal of the plurality of counters so that a detection signal can be inputted to the input terminal, A shaft overload characterized in that a small hole detection device corresponding to a rotary disk attached to the driven shaft is connected to a reset terminal of the plurality of counters so that a detection signal can be inputted to the reset terminal. Detection device.