JP2022178355A - Key wear detector - Google Patents

Abstract

To provide a key wear detector in which the degree of wear of a key of a power transmission system can be detected during operation of a power transmission device.SOLUTION: A key wear detector mechanically connects a rotating shaft of a servomotor 2 and a driving pulley by a key member. One end of the key member fits into a first groove formed in the rotary shaft, and the other end fits into a second groove formed in the inner peripheral wall of the driving pulley. A servo driver 51 detects the load acting on the servomotor 2 which repeats forwarding, reversing and stopping, and the detected load signal is output to a personal computer PC 53 via a programmable logic controller PLC 52, and the PC 53 computes, processes and determines the detected torque value. The PC 53 detects the input detection torque value, determines whether or not the detection torque value exceeds a reference value, and when the detection torque value exceeds the reference value, determines that the wear is abnormal and reports that the wear is abnormal.SELECTED DRAWING: Figure 7

Description

The present invention relates to a key wear detection device for detecting wear of a key used in a connecting portion between a rotating shaft and a rotating body.

In a conventional power transmission device, it is known that a key is used as a mechanical element in a connecting portion between a rotating body such as a belt or a gear and a rotating shaft that transmits power to the rotating body.
The key is fitted in both the groove formed in the outer wall of the rotating shaft on the drive side and the groove formed in the rotating body on the driven side to prevent slippage in the circumferential direction and prevent slipping of the rotating shaft on the drive side. It has the role of reliably transmitting the rotational force to the driven side.

However, this key requires replacement of elements due to mechanical wear. The extent of this wear cannot be visually confirmed by an external inspection during operation of the power transmission device.
For this reason, it has been difficult to visually recognize when and when the power transmission device needs to be stopped during operation.

The key of the connecting portion mechanically wears due to repeated forward and reverse rotation of the drive motor. In a machine or facility using this key structure, it is necessary to stop the power transmission device in order to replace parts when the degree of wear of the key increases due to aging.

The device of Patent Document 1 is not intended to detect the amount of wear of the key during operation of the power plant.

Japanese Patent Application Laid-Open No. 2003-172668

Conventionally, when trying to detect the presence or absence of key wear and the amount of wear, there was no choice but to stop the equipment of the power transmission device and inspect and investigate the amount of wear of the key. As a result, a long period of work stoppage due to facility stoppage was required, resulting in a decrease in the facility operating rate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to detect the degree of wear of a key in a power transmission system during operation of the power transmission system without stopping the equipment. An object of the present invention is to provide a wear detector.

The key wear detection device of the present invention comprises a rotating shaft (3) of a driving motor (2), a rotating body (10) rotating synchronously with the rotating shaft, and load means (20) for applying a load to the rotating body. and a key member having one end (31) fitted in a first groove (5) formed in the rotary shaft and the other end (32) fitted in a second groove (12) formed in the rotating body. (30), torque detection means (51) for detecting the torque value output from the drive motor, and key wear determination means (51) for determining the extent of key wear based on the detected torque value detected by the torque detection means 53).

The key member has, for example, one end fitted in the first groove formed in the outer peripheral wall (4) of the rotating shaft, and the other end formed in the inner peripheral wall (11) of the rotating body. fit into the second groove.
Any one of a gear device, a cam device, and a belt transmission device may be employed as the load means. Also, the load means is not limited to these devices.

In general, when a power transmission device such as a gear device, a cam device, or a belt transmission device is operated, a key member that mechanically connects the rotation shaft of the drive motor and the rotating body is mechanically changed every time the power transmission is repeatedly turned on and off. The amount of wear increases at the connecting points.

Based on the torque value detected by the torque detection means, the key wear amount determination means outputs a signal as a result of the magnitude of the amount of wear.
The operator can know the degree of wear of the key member based on the output result of the key wear amount determining means.

Therefore, the operator can detect the degree of wear of the key member while operating the mechanical equipment having the power transmission device. Since the actual physical wear of the key member can be known without conducting an investigation at the site where the key member is located, the operator can check the result of the key wear determining means. Based on this, it is possible to determine whether or not the key member needs to be replaced.

Therefore, by replacing the key member before the mechanical equipment breaks down, it is possible to reduce the number of failures and prevent the operating rate of the equipment or machines to be lowered. It is possible to detect wear while operating equipment and machinery without stopping the operation.

1 is a perspective view of a first embodiment of the invention; FIG. 1 is a schematic cross-sectional view of a first embodiment of the present invention; FIG. FIG. 4 is a diagram showing experimental data of the device according to the first embodiment of the present invention, and is a characteristic diagram showing the relationship between the amount of key wear, the detected torque value, and the motor operation. FIG. 4 is a schematic diagram showing an operation state and an operation image in relation to FIG. 3; FIG. 4 is a diagram showing experimental data of the device according to the first embodiment of the present invention, and is a characteristic diagram showing the relationship between the key wear amount and the detected torque value. FIG. 5 is an explanatory diagram of hypothetical events in the difference between the detected torque value of the apparatus according to the first embodiment of the present invention and the positional relationship between the key member, the rotating shaft, and the rotating body; 1 is a block diagram of an apparatus according to a first embodiment of the invention; FIG. 1 is a flow chart of an apparatus according to a first embodiment of the invention; FIG. 4 is a schematic diagram showing changes over time in the amount of wear of the key member;

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. In addition, the same code|symbol is attached|subjected to the substantially same structural part in several embodiment, and description is abbreviate|omitted.
(First embodiment)

In the first embodiment, the key wear detection device of the present invention is applied to a belt transmission device.
FIG. 1 shows a mechanical portion of a key wear detector to which the present invention is applied. This key wear detection device shows an embodiment applied to a key structure connecting a drive pulley of a belt transmission device and a rotation shaft of a drive motor.

As shown in FIG. 1, a rotating shaft 3 of a servomotor 2 as a driving motor attached to a frame 1 and a driving pulley 10 as a rotating body are connected by a key structure. A belt 20 wound around the drive pulley 10 is wound around a tail pulley (not shown) via bend pulleys 41 and 42 . By driving the belt 20, for example, a feeding mechanism is provided as a load means on the side of a driven pulley (not shown). By the operation of this feeding mechanism, for example, a pallet (not shown) is carried in and out.

As shown in FIGS. 1 and 2, a first groove 5 as a key groove is formed in the outer peripheral wall 4 of the rotary shaft 3 of the servomotor 2 . A drive pulley 10 as a rotating body has an inner peripheral wall 11 formed with a second groove 12 as a key groove. One end 31 of a rod-shaped key member 30 fits into the first groove 5 and the other end 32 fits into the second groove 12 . As a result, the rotating shaft 3 and the drive pulley 10 are mechanically connected, and the torque of the rotating shaft 3 on the drive side is transmitted to the drive pulley 10 on the driven side. The rotary shaft 3 rotates in both forward and reverse directions.

The servomotor 2 performs each operation of forward rotation, reverse rotation, or stop. As shown in FIG. 7, during operation, a programmable logic controller (PLC) 52 as a control device instructs a servo driver 51 according to a command from a personal computer (PC) 53, and a drive signal from the servo driver 51 is output to the servo motor 2. do.

The servo driver 51 follows commands from the PLC 52 and controls the output torque, rotation speed, and position of the servo motor 2 . The PLC 52 outputs the target value of the belt position to the servomotor 2 . A servo amplifier (not shown) that receives the target value from the PLC 52 supplies an output (electric power) necessary for the servo motor 2 to move according to the target value. An encoder (not shown) detects the actual rotational position and speed of the servomotor 2 and returns the electric signal as a feedback signal to the servo amplifier. An encoder takes the signal from the servo motor 2 and returns it to the servo amplifier side. Then, the target value output from the PLC 52 is compared with the feedback signal, and the output of the servomotor 2 is controlled so that the error approaches zero.

As a result, the drive pulley 10 is integrated with the rotating shaft 3 of the servomotor 2 to operate as desired. The drive pulley 10 rotates forward, reverse, or stops in synchronism with the forward rotation, reverse rotation, or stop of the rotating shaft 3 .

In the belt transmission, the key member 30 that mechanically connects the rotary shaft 3 and the driving pulley 10 mechanically wears due to deterioration of materials, deterioration of parts, generation of frictional force, and the like.
FIG. 9 is a schematic diagram showing shapes of a plurality of keys showing different degrees of key wear.

For example, as the amount of wear δ of the key member is shown in FIG. 9, the shape of the key member 30 changes in the order of (A), (B), and (C) as time elapses due to wear. From the initial (A) state of no wear, the amount of wear δ increases as the usage time increases.

After the wear amount δ1 in the intermediate period (B), in which the wear amount further increases, if left unattended, the wear amount δ2 (>δ1) in the final period (C) is reached and the operation is stopped.

A change in the amount of wear δ affects the value of the load due to the reaction of the driving force of the servomotor 2 . A load acts on the rotary shaft 3 of the servomotor 2 from the belt 20 shown in FIG.

As shown in FIG. 7, the servo driver 51 detects the load acting on the servo motor 2, outputs the detected load signal to the PC 53 via the PLC 52, and the PC 53 calculates, processes, and judges the detected torque value. .

As shown in FIG. 8, the PC 53 detects the input detected torque value (step S55), determines whether or not the detected torque value exceeds the reference value (step S56), and determines whether the detected torque value exceeds the reference value. If it exceeds, it is determined that the wear is the abnormal wear value, and an alarm is displayed indicating that the wear is abnormal (step S57). If the detected torque value does not exceed the reference value, return to the previous process.

In this way, the torque value is analyzed based on the load acting on the servomotor 2, and the operator is notified of the abnormal wear of the key member 30. FIG.
(Experiment 1)

In Experiment 1, the load applied to the servomotor changed with the amount of wear of the key member as one factor, and the operation period was 2 seconds.
FIG. 3 shows a raw waveform of one cycle of the servo motor torque test results. FIG. 3 shows changes in detected torque values for Experimental Examples 1 to 4 with different amounts of key wear.

Experimental conditions were the same for experimental examples 1 to 4, with a load of 60 kg and a belt tension of 320 N. For Experimental Examples 1 to 4, the wear amount δ (mm) of the key member was used as a variable.
Experimental example 1: wear amount δ = 0,
Experimental example 2: wear amount δ = 0.1,
Experimental example 3: wear amount δ = 0.2,
Experimental Example 4: The amount of wear δ was set to 0.5.

In Experimental Examples 1 to 4, one cycle was defined as stopping, forward rotation, stopping, and reverse rotation in 2 seconds.

The detected torque value was divided into stop period A, forward rotation period B, stop period C, and reverse rotation period D and analyzed. The waveform of the detected torque value is as shown in FIG.
FIG. 4 shows an image of the rotational positions of the rotating shaft, the rotating body, and the driving pulley during the operation period of 2 seconds for each experimental example.

A, B, C, and D shown in FIG. 4 show momentary images of operating states during the stop period A, forward rotation period B, stop period C, and reverse rotation period D shown in FIG.
(Experiment 2)

In Experiment 2, the peak values of the detected torque were compared based on the experimental data obtained in Experiment 1.
FIG. 5 shows experimental data extracted from the graph shown in FIG. 3 for each experimental example.

When the servomotor rotates forward, the peaks of the detected torque values for Experimental Examples 1 to 4 are assumed to be peaks 35, 36, 37, and 38 (positive), respectively.
When the servomotor is reversed, the peaks of the detected torque values are defined as valley (negative) peaks 55, 56, 57, and 58 for Experimental Examples 1 to 4, respectively.

Normality or abnormality was determined depending on whether these peak values exceeded or fell below the reference values for peaks or troughs, respectively.
As a result of the analysis, when comparing Experimental Examples 1 to 4, as the amount of key wear increases, peaks or troughs (positive or negative) increase during acceleration during both forward rotation and reverse rotation.

At this time, it can be seen that a torque peak occurs when a slip occurs between the rotating shaft and the drive pulley both during forward rotation and reverse rotation.
When slip occurs during forward rotation, slip occurs at the peak values of torque crests indicated by reference numerals 35, 36, 37, and 38, and when slip occurs during reverse rotation, torque troughs indicated by reference numerals 55, 56, 57, and 58 occur. Slip occurs at peak values.

FIG. 6 shows a schematic diagram of the hypothetical event. Slip occurs when the detected torque value exceeds the torque corresponding to the maximum static friction force.
In FIG. 6, A is when the unit rotates, B is when the detected torque value is equal to or less than the torque value corresponding to the maximum static friction force, and C is the occurrence of slip when the detected torque value exceeds the torque corresponding to the maximum static friction force. D indicates each position and relative positional relationship of the rotating shaft, the key member, and the drive pulley when they are integrally rotated by keeping the engagement of the key member.

In FIG. 6A, when the rotating shaft rotates clockwise, the drive pulley rotates together with the rotating shaft via the key member.
FIG. 6B shows that when the rotating shaft rotates clockwise, the torque corresponding to the frictional force is larger than the detected torque, and the rotating shaft rotates together.
FIG. 6C shows that when the detected torque becomes larger than the torque equivalent to the frictional force, the torque that rotates the rotary shaft clockwise is larger than the torque equivalent to the frictional force that tries to stop the drive pulley from the load means, so that the rotary shaft slips. do.
In FIG. 6D, it slips, but the rotation shaft and drive pulley rotate together due to the keyed connection.

A positive torque value peaks during acceleration at the start of forward rotation. A negative peak value of the torque value is taken during acceleration at the start of reverse rotation. In any of Experimental Examples 1, 2, 3, and 4, the detected torque value takes a peak value during normal rotation acceleration and during reverse rotation acceleration.

It can be seen that the detected torque value increases as the amount of key wear increases. A reference detected torque value for the detected torque value was identified.

In this embodiment, when the detected torque value exceeds a specific reference value, it is determined that an abnormal wear value should be reported.

According to this embodiment, in a power transmission device having a key structure, it is possible to detect key wear while operating mechanical equipment.
In the present invention, an abnormality of the key member can be notified based on the analysis result of the detected torque value.
(Other embodiments)

The determination in the first embodiment was performed based on the transition of the detected torque value in one cycle of forward rotation, stop, reverse rotation, and stop of the drive motor. It can also be performed based on the transition of the detected torque value in the cycle.
Determination of the analysis result of the present invention is not limited to the flow chart shown in FIG.

Examples of the judgment are the comparison of the peak value of the crest during forward rotation and the reference value, and the comparison of the peak value of the trough and the reference value during reverse rotation. When it is detected that either one of or exceeds the reference value, or when it is detected that both of them exceed the reference value, an abnormality may be notified.

Further, in the present invention, the determination may be based on the selection of the peak value or the characteristic of the detected torque waveform deviating from the standard.

Although the first embodiment described above is applied to the key structure that connects the rotating shaft of the belt transmission device motor and the driving pulley as the rotating body, the present invention can be applied to power transmission devices having other types of key structures. can.

As another embodiment, the embodiment is not limited as long as it is a rotating body that is connected to the rotating shaft using a key member instead of the pulley. The rotating body may be, for example, a gear or other rotating body for power transmission.

As described above, the present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the gist of the present invention.

2 servo motor (drive motor),
3 rotation axis,
4 outer wall,
5 first groove,
10 drive pulley (rotating body),
11 inner peripheral wall,
12 second groove,
20 belt (load means),
30 key member,
31 one end,
32 other end,
41 bend pulley,
42 bend pulley,
50 servo motors,
51 servo driver (torque detection means),
52 Programmable Logic Controller (PLC),
53 Personal computer (PC) (key wear determination means).

Claims (7)

a rotating shaft (3) of the drive motor (2);
a rotating body (10) that rotates in synchronization with the rotating shaft;
load means (20) for applying a load to the rotating body;
A key member (30) having one end (31) fitted in a first groove (5) formed in the rotating shaft and having the other end (32) fitted in a second groove (12) formed in the rotating body. )When,
Torque detection means (51) for detecting a torque value output by the drive motor;
A key wear detection device, comprising key wear determination means (53) for determining a degree of key wear based on the detected torque value detected by the torque detection means. The key member has one end fitted into the first groove formed in the outer peripheral wall (4) of the rotating shaft and the other end formed in the inner peripheral wall (11) of the rotating body. 2. The key wear detection device according to claim 1, wherein the key wear detection device is fitted in the second groove. 3. A key wear detector according to claim 1, wherein said load means is a gear device. 3. A key wear detector according to claim 1, wherein said load means is a cam device. 3. A key wear detection device according to claim 1, wherein said load means is a belt transmission device. manufacturing device. 6. The key wear determining means compares a peak value of the detected torque value with a reference value, and determines key wear when the peak value exceeds the reference value. The key wear detection device according to item 1. The key wear determination means compares the peak value of the detected torque value with a reference value based on the transition of the detected torque value in one cycle of forward rotation, stop, reverse rotation, and stop of the drive motor, and determines that the peak value is 6. The key wear detection device according to claim 1, wherein key wear is determined when the reference value is exceeded.

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