JPH0731007Y2 - Power transmission monitoring device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION << Industrial Application Field >> The present invention relates to a power transmission means such as a belt for transmitting rotational power from a prime mover in various machines including a rotary prime mover such as a machine tool, an automobile, and a conveyor. The present invention relates to a power transmission monitoring device capable of detecting an abnormal operation such as, for example, slipping or belt breakage.

<Prior Art> Conventionally, in a machine tool or the like, when the rotation of a motor that is a prime mover is transmitted by a belt, in order to detect belt slip and belt breakage, a rotation speed corresponding to a control signal given to the motor, There is a power transmission monitoring device that compares the rotational speed measured by the pulley on the power receiving side and outputs an abnormal signal that the transmission is abnormal when the speed difference exceeds an allowable value.

Usually, an appropriate value is selected for the tolerance as a criterion for determining whether or not there is an abnormality in this device, depending on the magnitude of the inertia of the power transmission rotary system. In other words, if the inertia is large,
It is large because the driven side is inferior when starting and stopping.
If it is small, the followability is good, so that it is made small, and an appropriate sensitivity is set so as not to detect anomaly excessively or to be too dull.

<Problems to be solved by the invention> However, when the inertia of the power transmission rotary system is always constant, it is sufficient to set a certain tolerance in advance as described above. In the case where the inertia varies, for example, in a machining center, when the machining tool is exchanged for each process, the tool inertia varies. Therefore, the power transmission monitoring devices used for these machining centers have the largest inertia. The tolerance is set based on the tool.
As a result, even if a transmission abnormality such as a belt slip occurs in the power transmission means when a tool with a small inertia is attached, it cannot be detected until the predetermined slip amount is reached.

Therefore, the present invention was made in order to eliminate such a drawback, and the purpose thereof is to constantly detect abnormalities with constant sensitivity even if the inertia of the power transmission rotary system is changed. An object of the present invention is to provide a power transmission monitoring device capable of detecting the.

<Means for Solving the Problems> The present invention aims to achieve the above-mentioned object by means for detecting the rotation speed of a driven part driven by a prime mover via a rotation transmission means and a plurality of rotations with different inertias. For each drive system, a memory that stores a temporal change pattern of the rotation speed that indicates a normal transmission state in each operating state of the prime mover at startup, steady state, and stop, and the rotation speed detected by the rotation speed detection means And a means for detecting a transmission abnormality of the rotation transmission means by comparing the pattern of the temporal change of the rotation speed of the corresponding rotation drive system in the memory with each other.

<Operation> In the present invention thus configured, when starting the prime mover for each of a plurality of rotary drive systems having different inertias in advance,
A rotation speed temporal change pattern representing a normal transmission state in each of the normal and stopped operating states is stored in a memory, and the rotational speed of the driven part detected by the rotation speed detection means and the temporal change pattern in the memory are stored. It is detected that an abnormality has occurred in the transmission means by performing a comparison process with the rotation speed of the corresponding rotary drive system.

<< Example >> Next, the Example of this invention is described based on drawing.

FIG. 1 shows an electrical configuration when the present invention is applied to a machine tool in which the rotation of a motor is transmitted by a belt. In the figure, a power transmission monitoring device 1 includes a CPU 11 and a ROM.
12, the RAM 13, the I / O circuit 14, and the rotation speed detection sensor 2 connected to the I / O circuit 14.

The motor 5 and the spindle 3 of the machine tool are connected to each other by a belt 4 which is wound between a pulley 51 and a pulley 31. While the motor control circuit 6 outputs a rotation command to the motor 5, the motor 5 rotates and drives the spindle 3 to rotate. The rotation speed detection sensor 2 installed facing the pulley 31 of the spindle 3 is composed of a proximity switch or the like, detects the rotation speed of the spindle 3 without contact, and outputs the detection signal.
It is sent to the I / O circuit 14.

The power transmission monitoring device 1 monitors the transmission abnormality of the belt 4 based on the rotation signal of the spindle 3 input to the I / O circuit 14 and the data regarding the rotation command to the motor 5 input from the motor control circuit 6. .

When the transmission abnormality can be detected, the I / O circuit 14 outputs an abnormality signal. The abnormal signal is sent to the alarm device 7 including a buzzer and the like, and is also sent to the motor control circuit 6 to switch the command to the motor 5 to a stop signal when necessary.

In addition, ROM12 and RAM which are memories in the power transmission monitoring device 1
In 13 is stored a pattern representing a change with time of the rotation speed at the time of start-up, steady state and stop, which corresponds to the inertia of the motor 5, the belt 4, the spindle 3, the machining tool and the like (not shown) in the machine tool. . Since the rotary system to which power is transmitted has different inertias when the type of tool to be attached or when a gear ratio is provided in the middle to switch the gear ratio, a plurality of patterns corresponding to the inertia are stored. To be done.

Based on the flowchart of FIG. 3, the abnormality diagnosis process performed by the power transmission monitoring device 1 will be described with reference to FIG.

First, when the start signal of the motor 5 is output from the prime mover control circuit 6 (step 31Y), the rotation indicated by the solid line in FIG. 2 for a fixed time of 0 to t ₁ second at the start corresponding to the start signal. The velocity pattern is read. On the other hand, the rotation speed of the spindle 3 input from the rotation speed detection sensor 2 changes with time indicated by the broken line in the figure. Here, the rotation speeds of the both are sequentially compared and judgment 1 is performed (steps 32 and 3).
3) If the difference x is not within the allowable value, it is determined to be abnormal and an abnormal signal is output (step 33NG, step 3).
8).

If the difference x is within the permissible value, after the time t ₁ when the rotation speed reaches almost N, until the stop signal is output (steps 32Y, 34N), it is a steady state and the rotation speed is N. The straight line pattern is called, the two are successively compared, and the determination 2 is made (step 35).

If the difference x is not within the allowable value, it is determined to be abnormal and an abnormal signal is output (step 35NG, step 38).

When the stop signal is output after the state where the difference x is within the allowable value has passed (step 34Y), the rotation speed pattern for a fixed time of t _{2 to} t ₃ seconds is called, and the two are sequentially compared. , Judgment 3 (steps 36N and 37). If the difference x is not within the allowable value, it is determined to be abnormal and an abnormality signal is output (step 37NG, step 38). Here, no abnormality is output as the determination result (step 37).
If the rotation is stopped (OK), the process ends (step 36 YES).

In this embodiment, slipping or cutting of the belt 4 is performed by a simple process of comparing a pattern representing a temporal change in the number of revolutions based on the content of a rotation command from the prime mover control circuit 6 with a rotation signal from the rotation speed detection sensor 2. Etc. can be detected quickly and highly accurately.

Further, even when the tool attached to the spindle 3 is replaced, the determination based on the rotation speed change pattern of the inertia corresponding to the tool is performed, and the determination processing corresponding to various situations becomes possible.

Although not shown as an example, an actual rotation speed of the motor 5 is detected, and a pattern showing a tolerance of the rotation speed corresponding to the rotation speed is prepared and compared with the rotation speed of the spindle 3. It is also possible to make a determination.

<Effect> As described above, the power transmission monitoring device according to the present invention shows a normal transmission state in each operating state at the time of starting, steady state, and stopping of the prime mover for each of a plurality of rotary drive systems having different inertias in advance. The temporal change pattern of the rotational speed is stored in the memory, and the rotational speed of the driven part detected by the rotational speed detecting means and the temporal change pattern of the rotational speed of the corresponding rotary drive system in the memory are compared and processed. By doing so, it is detected that an abnormality has occurred in the transmission means.Therefore, even when the inertia of the rotary drive system connected to the same prime mover is often changed, such as in a machining center, it is optimal each time. It is possible to detect abnormality of the transmission means with various sensitivity.

As a result, even small transmission abnormalities that could not be detected in the past can be detected, it is possible to speed up fault detection in such power transmission machines and prevent false fault detection notifications.
This has the effect of significantly improving the maintainability.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an embodiment in which the present invention is applied to a machine tool, FIG. 2 is an explanatory diagram showing a processing example in a transmission monitoring device, and FIG. 3 is a processing operation in a power transmission monitoring device. It is a flowchart shown. 1 ... Power transmission monitoring device 2 ... Rotation speed detection sensor 3 ... Spindle 4 ... Belt 5 ... Motor 6 ... Motor control circuit 7 ... Alarm device 11 ... CPU 12 ... ROM 13 ... RAM 14 ... I / O circuit 31 ... Pulley 51 ... Pulley

Claims (1)

[Scope of utility model registration request] 1. A means for detecting a rotational speed of a driven part driven by a prime mover via a rotation transmitting means, and a plurality of rotary drive systems having different inertias, respectively, when the prime mover is started, when it is stationary, and when it is stopped. Memory storing a temporal change pattern of the rotation speed indicating a normal transmission state in the operating state of the rotation speed, the rotation speed detected by the rotation speed detection means, and the time of the rotation speed of the corresponding rotation drive system in the memory. And a means for detecting a transmission abnormality of the rotation transmission means by comparing the pattern with the dynamic change pattern, and a power transmission monitoring device.