Belt tension detection device and belt tension detection method

Abstract

To provide a belt tension detection device and a belt tension detection method capable of detecting belt tension with a simple configuration.SOLUTION: A belt 5 is wound around a drive pulley 10, a bend pulley 11, a tail pulley 12, and the like, which are connected to a first servomotor 2 capable of rotating forward and backward. In the belt 5, fixed parts of a plurality of claw feeding devices 30 are fixed at equal intervals, the claw feeding device feeding out a plurality of pallets 7 movable on guide rails 8, 9 by repeating stop, feed, and stop. The load fluctuation accompanying the loosening of the belt 5 appears in an output value of a servo driver that detects a torque value output by the first servomotor 2. A personal computer detects the degree of looseness of the belt on the basis of the detected torque value detected by the servo driver.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a belt tension detection device and a belt tension detection method for detecting slack in a belt of a belt transmission device. [Background technology]

[0002] 2. Description of the Related Art As one type of power transmission device, a belt transmission device is known in which power is transmitted from a driving pulley to a driven pulley by a timing belt. For this type of belt transmission device, a belt slack detection device as disclosed in Patent Document 1 is known as a device for detecting slack in the belt.

[0003] This belt slack detector includes a thread-like detector element that is cut when the surface of the rotating belt makes sliding contact with the element for a certain period of time, and a notification means that is activated when the detector element is cut.

[0004] When the belt wound around the pulley loosens over time and gradually sags due to its own weight, the detector element that slides against the belt breaks. When the detector element breaks, an alarm is issued by the alarm means and a weight falls. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-39042 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to make it possible to detect the tension of a belt in a mechanism in which a load acts on the belt of a belt transmission device.

[0007] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a belt tension detection device and a belt tension detection method that are capable of detecting belt tension with a simple configuration without providing a sensor as a mechanical element. [Means for solving the problem]

[0008] The belt tension detection device of the present invention comprises a first drive motor (2), a drive pulley (10) connected to a rotary shaft of the first drive motor; A belt (5) wound around the driving pulley and the driven pulley (11, 12, 13, 15, 16); Apply load to the belt The claw feed device includes a fixed portion (31) fixed to the belt. A load means (30) a torque detection means (21) for detecting a torque value output by the first drive motor; a belt slackness detection means (23) for detecting a slackness of the belt based on a detected torque value detected by the torque detection means; A claw body (33) that is reciprocable relative to the fixed portion; a second drive motor (25) that reciprocates the claw body relative to the fixed portion; A configuration comprising the following is adopted.

[0009] Generally, when a belt wound around multiple pulleys becomes loose, a mechanism connected to the belt becomes misaligned. When a mechanism becomes misaligned, a reaction occurs, causing a load fluctuation on the belt, which appears in the torque value of the drive motor.

[0010] According to the present invention, the torque value of the drive motor linked to the belt behavior and state is collected, and the output result corresponding to the belt slackness is analyzed. As a result of the analysis, the belt slackness is detected.

[0011] The torque value generated by torque detection means such as a torque driver of the belt-type power transmission device of the present invention is used as the detection value, and slack in the belt tension is detected based on this detected torque value.

[0012] The amount of displacement corresponding to the degree of slack in the belt is detected as an electrical signal. The torque value increases as the amount of positional deviation corresponding to the amount of displacement as the electrical signal increases. The degree of slack in the belt is detected based on the amount of displacement corresponding to the corresponding positional deviation signal.

[0013] According to the belt tension detection device of the present invention, it is possible to detect the degree of slack in a belt without the physical operation of breaking off the detection element caused by an increase in the amount of slack in the belt.

[0014] The belt tension detection method of the present invention is a method for detecting the tension of a belt wound around a drive pulley and a driven pulley, and includes the steps of detecting a torque value output by a drive motor that drives the drive pulley, comparing a peak value of the detected torque value with a reference value, and determining that the belt is largely loose when the peak value exceeds the reference value. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a claw feed device and a pallet transport device according to a first embodiment of the present invention; [Diagram 2] Cross-sectional view of line II-II in Figure 1. [Diagram 3] FIG. 2 is an enlarged perspective view of a portion III in FIG. [Figure 4] FIG. 2 is a partially enlarged perspective view showing the pawl feeding device and a second drive motor according to the first embodiment of the present invention. [Diagram 5] Cross-sectional view of line VV in Figure 4. [Figure 6] FIG. 1 is a block diagram of a system configuration according to a first embodiment of the present invention. [Figure 7] 4 is a flowchart showing an example of an operation according to the first embodiment of the present invention. [Figure 8] FIG. 4 is an enlarged perspective view corresponding to FIG. 3 and showing the release state of the claw body. [Figure 9] FIG. 2 is a partially enlarged perspective view showing the tension adjustment pulley of the first embodiment of the present invention. [Figure 10]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 detected torque value, the belt operation, and the pawl feed operation. [Figure 11] FIG. 11 is an enlarged characteristic diagram of part XI in FIG. [Figure 12] 5A and 5B are schematic diagrams illustrating an image of the operation of the feed claws and belts relative to a pallet according to the first embodiment of the present invention. [Figure 13] FIG. 13 is a schematic explanatory diagram showing the relationship between the feed pawls and the pallet when the belt tension is at a reference level. [Figure 14] FIG. 13 is a schematic explanatory diagram showing the relationship between the feed pawls and the pallet when the belt tension is reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that, in a plurality of embodiments, substantially the same components are denoted by the same reference numerals, and description thereof will be omitted. First embodiment

[0017] In the first embodiment, the belt tension detection device of the present invention is applied to a belt transmission device that drives a pallet conveying device. FIG. 1 shows a mechanical portion of a belt tension detection device according to a first embodiment of the present invention.

[0018] 1, 2 and 3, in the belt transmission device 35, a drive pulley 10 is fixed to a rotating shaft 3 of a first servo motor 2 attached to a frame 1. A belt 5 wound around the drive pulley 10 is wound around a bend pulley 11, a tail pulley 12, a bend pulley 13, a tension adjusting pulley 14, a bend pulley 15 and a bend pulley 16.

[0019] The multiple pawl feed devices 30 as a load means are attached to the belt 5 between the bend pulley 11 and the tail pulley 12. As shown in Figures 3 to 5, the multiple pawl feed devices 30 have multiple fixing parts 31 fixed to the upper belt 5 at equal intervals in the direction in which the belt extends.

[0020] As shown in Figures 4 and 5, the multiple pawl feed device 30 has an eccentric plate 27 eccentrically provided on a disk 26 attached to the rotating shaft of a second servo motor 25, which corresponds to the second drive motor described in the claims.

[0021] When the disk 26 rotates forward or backward, the shaft 28 rotates forward or backward via the shaft 39 connected to the eccentric plate 27. When the shaft 28 rotates about its axis, the arm 29 rotatably attached to the other end of the lever 38 reciprocates, and the lever 40 connected to the other end of the arm 29 rotates about a fulcrum 43, so that the movable plate 44 connected to the other end of the lever 40 can reciprocate in the direction of the arrow 45. The claw body 33 engaged with the movable plate 44 can reciprocate in the direction of the arrow 45 relative to the fixed part 31. FIG. 5 shows a state in which the claw body 33 fits into a groove 48 of the pallet 7, but when the claw body 33 moves rightward in FIG. 5 relative to the groove 48 of the pallet 7, the claw body 33 is released.

[0022] As shown in Fig. 1, multiple pallets 7 are movable in the direction of arrow 17 on guide rails 8, 9. Pallet 7 has grooves 48 on its side into which claw body 33 of claw feed device 30 can fit. Fig. 3 shows the claw body 33 fitted into groove 48 of pallet 7, and Fig. 8 shows the claw body 33 released from groove 48 of pallet 7.

[0023] By driving the second servo motor 25, the claw body 33 is extended to enter an engaged state as shown in Fig. 3, and the claw body 33 is contracted to enter a released state as shown in Fig. 8. The multiple claw feed devices 30 arranged at equal intervals on the belt 5 are controlled in position by the second servo motor 25 linked to the belt position control by the first servo motor 2, and sequentially stop and feed the pallet 7, repeatedly transporting it in the direction of the arrow 17 shown in Fig. 1.

[0024] Next, the conveyance of a pallet by the interlocking of the belt transmission device 35 and the pawl feed device 30 will be described with reference to Figs. 12A, 12B, 12C and 12D.

[0025] 12A, the claw body 33 is in a released state in which it is released from the groove 48 of the pallet 7 relative to the fixed part 31 fixed to the belt 5. From this state, the claw body 33 is moved in the direction indicated by the two-dot chain line by the forward rotation of the second servo motor 25.

[0026] Next, as shown in FIG. 12B, the claw body 33 fits into the groove 48 of the pallet 7, and when the first servo motor 2 is driven in the forward direction to move the belt 5 in the direction of the arrow 46 (forward), the pallet 7 that engages with the claw body 33 moves in the pallet conveying direction, parallel to the direction of movement.

[0027] Next, as shown in FIG. 12C, the belt 5 is stopped, and the second servo motor 25 is driven in the reverse direction to release the claw bodies 33 from the grooves 48 of the pallet 7.

[0028] 12D, the second servo motor 25 is stopped, the pallet 7 is maintained at that position, the first servo motor 2 is reversed, and the belt 5 is returned (moved backward) in the return direction of the arrow 47. In this way, by repeating the operations A, B, C, and D in Figure 12 in order, the belt 5 repeatedly moves back and forth (stop, forward, stop, return), and multiple pallets 7 are stopped and forwarded in sequence, thereby transporting multiple pallets 7 in one direction.

[0029] Next, the operation of driving the belt 5 will be described.

[0030] The first servo motor 2 performs any one of the following operations: forward rotation, reverse rotation, and stop. As shown in Fig. 6, a programmable logic controller (PLC) 22 as a control device instructs a servo driver 21 in response to a command from a personal computer PC23, and a drive signal of the servo driver 21 is output to the first servo motor 2.

[0031] The servo driver 21 follows commands from the PLC 22 and controls the output torque, rotational speed, and position of the servo motor 2. The PLC 22 outputs a target value for the belt position to the servo motor 2. A servo amplifier (not shown) receives the target value from the PLC 22 and supplies the output (power) required 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 servo motor 2 and returns the electrical signal as a feedback signal to the servo amplifier. The encoder takes in the signal from the servo motor 2 and returns it to the servo amplifier. The target value output by the PLC 22 is then compared with the feedback signal, and the output of the servo motor 2 is controlled so that the error approaches zero.

[0032] As a result, the drive pulley 10, which rotates integrally with the rotating shaft 3 of the servo motor 2, controls the belt 5 to a desired position. The rotating shaft 3 is controlled to stop, rotate forward, stop, reverse, and stop at a desired speed and position to drive the belt 5. The belt 5 repeats the operations of stopping, feeding, stopping, and returning. A second servo motor 25 is driven in synchronization with this first servo motor 2, and the position of the claw feed device 30 is controlled. As a result, the pallets 7 are sequentially fed, stopped, and fed repeatedly in the conveying direction, and are conveyed in one direction of the arrow 17 shown in FIG. 1.

[0033] The belt transmission device 35 applies torque fluctuations to the belt 5 due to the load acting from the claw feed device 30. For example, as shown in Fig. 13, if the belt tension, which was initially at a standard level, gradually loosens, an increase in load occurs due to a collision when the claw body 33 fits into the groove 48 of the pallet 7, as shown in Fig. 14.

[0034] Due to loosening of the belt 5 caused by aging, etc., the torque value detected by the first servo motor 2 from the drive pulley 10 via the belt 5 fluctuates due to a reaction to the repeated change in behavior of the claw body 33 as it engages with and disengages from the groove in the pallet 7.

[0035] 6, the servo driver 21 detects the load acting on the first servo motor 2 and outputs the detected load signal to the PC 23 via the PLC 22, which then calculates, processes and judges the detected torque value. Here, the servo driver 21 corresponds to the torque detection means recited in the claims, and the PC 23 corresponds to the belt slackness determination means recited in the claims.

[0036] 7, the PC 23 detects the input detected torque value (step S51), determines whether the detected torque value exceeds a reference value (step S52), and if the detected torque value exceeds the reference value, determines that an abnormality in belt tension has occurred and issues a warning indicating that the tension is abnormal (step S53). If the detected torque value does not exceed the reference value, the process returns to the previous process.

[0037] In this manner, the torque value is analyzed based on the load acting on the servo motor 2, and the occurrence of an abnormality in the tension of the belt 5 is notified to the operator. (Experiment 1)

[0038] In experiment 1, the load applied to the first servo motor, which changes with the belt tension as one of its elements, was compared over an operating period of 2 seconds with changes in the detected torque value output during this operating period.

[0039] The raw waveform of one cycle of the servo motor torque experiment results is shown in Fig. 10. Fig. 10 shows the transition of the detected torque value for each of Experimental Examples 1 to 4, which have different belt tension settings.

[0040] The experimental conditions for Experimental Examples 1 to 4 were as follows, based on the belt tension reference value. Experimental Example 1: Belt tension standard, Experimental example 2: Belt tension 190N, Experimental example 3: Belt tension 105N, Experimental Example 4: Belt tension was set to 50N or less.

[0041] In Experimental Examples 1 to 4, one cycle was defined as stopping, moving, stopping, and returning the belt for 2 seconds. The period when the belt was moving corresponds to the nail-engaged state, and the period when the belt was returning corresponds to the nail-removed state.

[0042] In the above one cycle, before the pallet starts to be conveyed, when the belt is stopped and before it starts to move, and during the initial operation of the first servo motor, the detected torque value corresponding to the degree of slackness of the belt fluctuates greatly. An enlarged view of the resulting waveform is shown in Fig. 11.

[0043] When the belt slack is small (when the initial belt tension setting is maintained), peak 55 of the detected torque value falls below the reference value as shown in Experimental Example 1. When the belt tension begins to slacken, before the feed operation starts, peaks 56, 57, and 58 of the detected torque value exceed the reference value as shown in Experimental Examples 2, 3, and 4.

[0044] It can be seen that the maximum torque value detected when the belt is stopped before the belt starts to be fed increases as the degree of slack in the belt tension increases.

[0045] In this embodiment, when the detected torque value exceeds a specific reference value, it is determined that an abnormal value for slack in the belt tension needs to be notified.

[0046] According to this embodiment, in a power transmission device having a belt, it is possible to detect slack in the belt tension while the machine equipment is operating.

[0047] In the present invention, an abnormality in the belt tension can be notified based on the analysis results of the detected torque value.

[0048] Prevents misalignment caused by loose belts. Eliminates the need to check belt tension, improving operation rates. Detects belt tension while equipment or machinery is in operation, without stopping the operation.

[0049] Therefore, by adjusting the belt tension before the mechanical equipment breaks down, the number of breakdowns can be reduced and a decrease in the availability rate of the operating equipment or machine can be prevented. When a slackness in the belt is detected, the tension of the belt is adjusted by vertically adjusting the position of the tension adjusting pulley 14 of the belt tension mechanism shown in FIG.

[0050] Generally, in a belt transmission device, if the driving shaft is rotated in the normal direction, stopped, reversed, and stopped repeatedly, the degree of slack in the belt gradually increases due to aging.

[0051] The result of the degree of the belt slackness is determined based on the torque value detected by the torque detection means and its transition (change in the detected torque value over a predetermined period of time). As a result of the determination, the belt slackness determination means outputs a slackness detection signal.

[0052] Based on the output result of the belt slackness determining means, the operator can know the degree of belt slackness.

[0053] Therefore, the belt tension detection device of the present invention can detect the degree of belt slack based on the operation of the control device of the belt drive motor. The degree of belt slack can be detected without providing a sensor as a mechanical element for detecting the actual amount of slack in the belt, without physically measuring the tension using a machine including a sensor, and without palpation by an operator.

[0054] The operation of the belt transmission device is continued, and if an abnormality such as loosening of the belt occurs during the operation, the computer outputs an output abnormality signal, thereby making it possible to avoid the occurrence of an actual breakdown.

[0055] Furthermore, by detecting the abnormality signal output by the computer, an operator can carry out mechanical operations to adjust the belt tension before a breakdown occurs, thereby preventing breakdowns and improving the availability of the equipment. (Other embodiments) In the above embodiment, the loading means is a pawl feed device, but in the present invention, the loading means may be any mechanism, machine, etc. that applies a load to the belt. The number and form of the loading means are not limited.

[0056] As described above, the present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit and scope of the present invention. [Explanation of symbols]

[0057] 2 a first servo motor (a first driving motor); 5 belt, 7 pallets, 8, 9 Guide rail (guide member), 10 Drive pulley (rotating body), 11 Bend pulley, 12 Tail pulley, 14 tension adjustment pulley, 21 Servo driver (torque detection means), 22 Programmable logic controller (PLC), 23 Personal computer (PC) (belt slackness determination means), 25 second servo motor (second drive motor), 30 claw feed device (loading means), 31 Fixed part, 32 Moving parts, 33 Claw body, 35 Belt transmission device, 48 Groove, 60 Pallet transport device.

Claims

1. A first drive motor (2); A drive pulley (10) connected to a rotary shaft of the first drive motor; A belt (5) wound around the driving pulley and the driven pulley (11, 12, 13, 15, 16); A load means (30) which is a claw feed device that applies a load to the belt and includes a fixed portion (31) fixed to the belt; a torque detection means (21) for detecting a torque value output by the first drive motor; a belt slackness detection means (23) for detecting a slackness of the belt based on a detected torque value detected by the torque detection means; A claw body (33) capable of reciprocating relative to the fixed portion; a second drive motor (25) that drives the hook body reciprocally relative to the fixed portion.

2. A pallet (7) having a groove (48) into which the claw body can be fitted; 2. The belt tension detection device according to claim 1, further comprising: a guide member (8, 9) for guiding the pallet so as to be transportable in a direction parallel to the direction of movement of the belt.

3. 3. The belt tension detection device according to claim 2, further comprising a pallet transport device (60) which transports the pallet in one direction by advancing the belt with the claw body engaged in the groove of the first pallet, reversing the belt with the claw body not engaged in the groove of the first pallet, advancing the belt with the claw body engaged in the groove of the next second pallet, reversing the belt with the claw body not engaged in the groove of the second pallet, and repeating the same process thereafter, thereby repeatedly stopping and feeding the pallet in one direction.

4. 4. The belt tension detection device according to claim 1, wherein the first drive motor is a servo motor capable of rotating in both forward and reverse directions.

5. 5. The belt tension detection device according to claim 1, wherein the belt slackness detection means comprises: a belt slackness determination means that compares a peak value of the detected torque value with a reference value and determines that the belt slackness is large when the peak value exceeds the reference value.

6. 5. The belt tension detection device according to claim 1, wherein the belt slack detection means compares a peak value of a detected torque value with a reference value when the first drive motor is initially started, the belt is in a stopped state and before the belt is fed, and determines that the belt has a large slack when the peak value exceeds the reference value.

7. The belt tension detection device according to any one of claims 1 to 6, further comprising a tension adjustment pulley (14).

8. A method for detecting tension of a belt wound around a drive pulley and a driven pulley, comprising the steps of: a step of controlling the position of the belt by a first drive motor, controlling the position of a claw body that can be switched between engagement and release with a pallet by a second drive motor, the claw body arranged on the belt repeatedly switching between an engagement state and a release state with the pallet, and transporting the pallet in the engagement state; detecting a torque value output by a drive motor that drives the drive pulley; comparing a peak value of the detected torque value with a reference value; and determining that the belt is largely loose when the peak value exceeds the reference value.

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