JP2005351683A - Fastening tool, its management system, and set of those - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for more surely managing the measuring accuracy of a torque measurement means provided with a fastening tool. <P>SOLUTION: The management system for managing the fastening tool equipped with the torque measurement means comprises: a torque measurement means for measuring the generation torque of the fastening tool in the management system; an input means for inputting the torque measured by the measurement means at the fastening tool side to the management system side; a calculation means for calculating the index representing the rate of difference between the torque measured by the torque measurement means of the management system side and the torque measured by the torque measurement means of the fastening tool side; and a teaching means for teaching the index calculated by the calculation means to the fastening tool. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for managing a tightening tool for tightening screws (bolts, nuts, screws, etc.). In particular, the present invention relates to a technique for managing the torque measurement accuracy of a tightening tool having a torque measuring means.

As a tightening tool for tightening screws, a tightening tool having means for measuring a torque applied to the screws or a torque applied to the screws is known. Such a tightening tool is widely used in manufacturing sites of industrial products including automobiles.
In industrial products, the tightening torque of screws is specified, and it is necessary to strictly control the tightening torque at the time of tightening at the manufacturing site. Since it takes a lot of labor and time to individually inspect the tightening torque of all screws, the tightening torque usually depends on the measured value of the torque measuring means provided in the tightening tool. Is managing. In this method, it is necessary to ensure the measurement accuracy of the torque measuring means of the tightening tool. Normally, the measurement accuracy of the torque measuring means provided in the tightening tool is checked before the work starts, and if a measurement error occurs, the torque measuring means of the tightening tool is calibrated. Then, the measurement accuracy of the torque measuring means of the tightening tool is confirmed again after the work is completed, and it is guaranteed whether or not the tightening work performed from the start of the work to the end of the work is appropriate.
The measurement accuracy of the torque measuring means of the tightening tool can be confirmed using a test apparatus described in Patent Document 1, for example. The test apparatus of Patent Document 1 includes a test shaft that simulates screws, measures the torque loaded on the test shaft by the tightening tool, and compares the torque measured by the tightening tool itself with the tightening tool. This is to confirm the torque measurement accuracy.
German Patent Invention No. 3305457

The conventional test apparatus only measures the measurement accuracy of the torque measuring means provided in the tightening tool. If a measurement error occurs, the operator needs to calibrate the torque measuring means of the tightening tool. In addition to forcing the operator to perform troublesome work, it is possible that measurement errors are not correctly removed due to human error. If a tightening tool having a measurement error is used, it may be necessary to inspect all the screws fastened with the tightening tool.
The present invention solves the above problems. The present invention provides a technique for more reliably managing the measurement accuracy of the torque measuring means provided in the tightening tool.

The present invention provides an apparatus for managing a tightening tool having torque measuring means. This management device is provided on the management device side to measure torque generated by the tightening tool, to the management device side to input torque measured by the torque measurement device on the tightening tool side, and to the management device Calculating means for calculating an index indicating the degree of difference between the torque measured by the torque measuring means on the side and the torque measured by the torque measuring means on the tightening tool, and teaching the tightening tool the index calculated by the calculating means Teaching means.
The torque measuring means on the management device side and the torque measuring means on the tightening tool side may measure the torque applied to the screws in real time, or measure the final torque applied to the screws in real time. It may be a thing, and the last torque added to screws may be measured afterwards. When the torque applied to the screws is measured in real time, the index is calculated from the torque measured simultaneously by the torque measuring means on the management device side and the torque measuring means on the fastening tool side. When measuring the final torque applied to the screws, an index is calculated from the final torque measured by the torque measuring means on the management device side and the torque measuring means on the fastening tool side.

This management device measures the torque generated (or generated) by the tightening tool. On the other hand, a value obtained by measuring the same torque by the torque measuring means on the tightening tool side is obtained from the tightening tool side. Then, an index indicating the degree of difference between the two is calculated.
The torque measuring means on the tightening tool side must be small and simple, and the reliability of the measured value is low. On the other hand, highly reliable torque measuring means with high reliability can be prepared on the management device side.
Therefore, the difference between the torque measured by the torque measuring means on the management device side and the torque measured by the torque measuring means on the tightening tool side indicates the measurement error of the torque measuring means on the tightening tool side, and they are different. The index indicating the degree indicates the degree of measurement error of the torque measuring means on the tightening tool side. By teaching the calculated index to the tightening tool, the tightening tool can know the measurement error occurring in its torque measuring means. Furthermore, if the index is used, the tightening tool can calibrate its own torque measuring means by itself. There is no need for the operator to calibrate the torque measuring means of the tightening tool.
In this management apparatus, the measurement error of the torque measuring means on the tightening tool side is taught to the tightening tool. The clamping tool can calibrate its own torque measuring means by itself. Since no operator is involved, human error can be eliminated, and the torque measurement accuracy of the tightening tool can be guaranteed (maintenance is maintained).

  In the above management apparatus, a storage unit storing a predetermined range is added to the index, and the teaching unit is within a predetermined range where the index calculated by the calculation unit is stored in the storage unit. If present, it is preferable not to teach the index to the tightening tool.

  The measuring device on the management device side also has a limit in the repeatability of torque measurement. The torque measurement means on the tightening tool side also has a limit in the repeatability of torque measurement. Therefore, the difference between the torque measured by the measuring means on the management device side and the torque measured by the torque measuring means on the tightening tool side includes an error due to the above repeatability. If the calibration process is performed for every minute error caused by the measurement accuracy of the measuring means, the measurement error of the torque measuring means of the tightening tool may be increased. Therefore, when the measurement error is slight and within the normal range, it may be preferable not to calibrate the torque measuring means of the tightening tool. For this purpose, the normal range of the index is stored, and if the calculated index is within the normal range, the calculated index is not taught to the tightening tool.

  Further, for example, the tightening tool may be damaged due to impact or the like, and the measurement accuracy of the torque measuring means of the tightening tool may be significantly reduced. In such a case, it is necessary to first repair the damaged portion rather than calibrating the torque measuring means. For example, if the torque measuring means of an abnormal tightening tool is forcibly calibrated, a damaged tightening tool may continue to be used depending on the measurement accuracy that has been recovered from the moment. Therefore, when the measurement error is large and exceeds the calibratable range, the torque measuring means of the tightening tool may not be calibrated. That is, it is preferable to store the uncalibrated range of the index, and if the calculated index is within the uncalibrated range, the calculated index is not taught to the tightening tool. In this case, for example, the operator may be notified of this fact, and the disassembly and inspection of the tightening tool may be promoted.

The index calculated by the calculating means is preferably the ratio of the torque measured by the torque measuring means on the management device side and the torque measured by the torque measuring means on the tightening tool side.
The calculating means can easily calculate the index, and the tightening tool taught with the index can easily calibrate its own measurement error. For example, the tightening tool can correctly calibrate its torque measuring means by multiplying the torque value measured as before by the taught ratio value.

In the above apparatus, accumulation storage means for accumulating and storing an index taught to the tightening tool by the teaching means, and integrated index calculation means for accumulating the index group accumulated and stored in the accumulation storage means, The second storage means for storing the permissible range of the accumulation index is added, and the teaching means tightens the index calculated by the calculation means only when the accumulation index calculated by the accumulation index calculation means is within the permissible range. It is preferable to teach the accessory tool. Accumulating the index group means converting the index group into one index indicating the error tendency indicated by each index of the index group. For example, if each index indicates a difference, it indicates that all index groups are added. Alternatively, if each index indicates a ratio, it indicates that all ratio values are multiplied.
The torque measurement accuracy of the tightening tool decreases due to deterioration due to use and deterioration with time. Specifically, the measurement error of torque measurement increases, and the repeatability of torque measurement decreases. In such a case, maintenance such as replacement of consumable parts is required rather than calibrating the torque measuring means. Even if you calibrate the torque measurement means of a tightened tool that has deteriorated, you cannot remove the decrease in repeatability, and the tightening tool whose measurement accuracy has fallen depends on the measurement accuracy that has recovered momentarily. May continue to be used. Therefore, when a large measurement error occurs in the torque measuring means as compared with a new state, the torque measuring means of the tightening tool may not be calibrated.
In this apparatus, the teaching means teaches and stores the index taught to the tightening tool, and the accumulated index group is accumulated to calculate the accumulated index. The stored and stored index is an index that has been taught to the tightening tool in the past, and indicates a measurement error that has been removed from the torque measuring means of the tightening tool in the past. That is, the integrated index indicates the total of measurement errors that have been removed from the torque measuring means of the tightening tool so far, and the torque inherently generated in the torque measuring means of the tightening tool with respect to the new state. The measurement error is shown. This apparatus stores the permissible range of the accumulation index, and only teaches the tightening tool the index calculated by the calculation means when the calculated accumulated index is within the permissible range. On the other hand, if the calculated accumulated index is not within the allowable range, the index is not taught to the tightening tool. In this case, for example, the operator may be notified of this fact and the maintenance of the tightening tool may be promoted.

In the above apparatus, when the index calculated by the calculating means is a ratio of the torque measured by the torque measuring means on the management apparatus side and the torque measured by the torque measuring means on the tightening tool side, the integrated index calculating means The accumulation index to be calculated can be a product obtained by multiplying all the values of the plurality of ratios accumulated and stored in the accumulation storage means.
The calculation means and the accumulation index calculation means can easily calculate the index and the accumulation index, and the accumulation index can correctly indicate the degree indicated by each index.

  In the above apparatus, it is preferable that the teaching unit includes a communication unit capable of wirelessly and / or wiredly communicating with a communication unit included in the tightening tool. Thereby, the index calculated by the calculating means can be taught to the tightening tool via the communication means, and the torque measurement accuracy of the tightening tool can be managed easily.

The present invention also provides a new and useful clamping tool. One tightening tool provided by the present invention is a tightening tool having a torque measuring means, and a sensor for detecting an index corresponding to the torque, and a torque from the detection index of the sensor transmitted from an external device. Communication means for receiving data used for calculating the torque, and torque calculation means for calculating torque from the index detected by the sensor using the data received by the communication means.
Further, another tightening tool provided by the present invention is a tightening tool including a torque measuring unit, and the torque measuring unit detects an index corresponding to the torque, and the index and torque detected by the sensor. Basic relationship storage means for storing the basic relationship, index storage means for storing a correction index transmitted from an external device, sensor detection index, basic relationship stored in the basic relationship storage means, and index Torque calculation means for calculating torque from a correction index stored in the storage means is provided.
These tightening tools can calibrate their own torque measuring means by themselves using, for example, the above management device, and the measurement accuracy of the torque measuring means is reliably managed.

Furthermore, by using the present invention, a tightening tool set is provided. This tightening tool set can be constituted by the above-described management device and the above-described tightening tool.
In this tightening tool set, the measurement accuracy of the torque measuring means provided in the tightening tool is more reliably managed. If this tightening tool set is deployed at, for example, an industrial product manufacturing site, the tightening torque of screws used in the industrial product can be correctly managed.

  The present invention provides a technique for more reliably managing the measurement accuracy of the torque measurement means provided in the tightening tool.

First, the main features of the embodiments described below are listed.
(Embodiment 1) The management device is pivotally supported and has an inspection shaft that is formed to be engageable with the main shaft of the tightening tool, a brake device that applies a braking torque to the inspection shaft, A torque sensor for detecting an index corresponding to the torque that is present, and a calculation means for calculating the torque applied by the spindle of the tightening tool to the inspection axis from the detected index of the sensor. The management device can measure the torque applied to the inspection shaft by the tightening tool by rotating the inspection shaft with the tightening tool.
(Mode 2) The management device includes torque-angle information that describes the relationship between the rotation angle and the torque, and an angle sensor that detects the rotation angle of the inspection shaft. The brake device adjusts the braking torque applied to the inspection shaft based on the output of the angle sensor, the output of the torque sensor, and the torque-angle information. The management device can make the relationship between the rotation angle of the inspection shaft and the torque necessary for further rotating the inspection shaft at the rotation angle substantially equal to the stored torque-angle information.
(Mode 3) The management device includes a communication device. The management device can communicate with a communication device provided in the tightening tool.
(Mode 4) The management device includes a display device. The management device can display the result of the inspection of the tightening tool on the display device and notify the operator or the like.
(Mode 5) The tightening tool includes a memory circuit. The tightening tool can store the number of times it is used, identification information assigned to it, a calibration coefficient taught by the management device, and the like in a memory circuit.
(Mode 6) The tightening tool includes a communication device. The tightening tool can communicate with a communication device provided in the management device.

(Example 1) Hereinafter, a tightening tool set which is an example embodying the present invention will be described with reference to the drawings.
FIG. 1 schematically shows a tightening tool set according to this embodiment, a tightening tool 10 for tightening screws (bolts, nuts, screws, etc.), and a management apparatus for managing the tightening tool 10. 50 is shown. FIG. 2 shows an electrical configuration of the tightening tool 10 and the management device 50. As shown in FIGS. 1 and 2, the management device 50 mainly includes a brake unit 60 and a computer 90. The brake unit 60 and the computer 90 are connected by a communication cable 88. Although not shown, the tightening tool set includes a plurality of groups of tightening tools 10.
The fastening tool 10 is assumed to be used in a production line for industrial products such as automobiles. In other words, the tightening tool 10 is configured so that a predetermined tightening portion (for example, a bolt for fixing the engine to the vehicle body) in a predetermined process (for example, an engine assembling process) is set to a predetermined tact time (for example, per vehicle body). 10 seconds), and tightening with a predetermined tightening torque is required.
The management device 50 is a device for maintaining the tightening tool group 10 in a normal state. Furthermore, the tightening operation performed by the tightening tool is managed by maintaining the tightening tool 10 in a normal state, and the tightening torque of the tightening portion tightened by the tightening tool 10 is managed. It is a device for. Therefore, the management device 50 maintains the individual tightening tools 10 in a normal state, finds a tightening tool 10 that is difficult to maintain the normal state, and uses the abnormal tightening tool 10. It is required to prevent this.

First, the tightening tool 10 will be described. The tightening tool 10 is a power tool for tightening screws (bolts, nuts, screws, etc.). As shown in FIG. 1, the tightening tool 10 includes a case 11, a main shaft 16 protruding from the case 11, and an engagement member 20 attached to the tip of the main shaft 16. Further, a battery 28 serving as a power source for the tightening tool 10, a trigger switch 22 for an operator to operate the tightening tool 10, a torque setting switch 32, and the like are provided.
The main shaft 16 is rotatably supported with respect to the case 11 or the like of the tightening tool 10 and is configured to be rotatable by a motor or the like described later.
The engaging member 20 is fixed to the main shaft 16 so as not to rotate relative to the main shaft 16 in the rotational direction. On the other hand, the main shaft 16 is fixed in a removable manner in the axial direction. The engaging member 20 is formed in a shape that can be engaged with the heads of the screws. In the tightening tool 10, a plurality of engaging member 20 groups are prepared corresponding to various screws, and the engaging member 20 corresponding to the type of screws to be tightened is selected and attached to the main shaft 16. be able to.
The trigger switch 22 is a switch for operating rotation / stop of the main shaft 16. The trigger switch 22 can also adjust the rotation speed of the main shaft 16, and the main shaft 16 rotates faster as the trigger switch 22 is operated more greatly (as it is pulled larger). The torque setting switch 32 is a switch for setting a tightening torque, and outputs a voltage corresponding to the set tightening torque. The torque setting switch 32 can be configured using, for example, a dial type volume switch.

As shown in FIG. 2, the tightening tool 10 includes a motor 12 for rotating the main shaft 16 and a motor control circuit 26 inserted on a circuit connecting the motor 12 and the battery 28.
The motor 12 is a brushless DC motor and operates by receiving power from the battery 28. The motor 12 is designed so that the rotor is miniaturized and the moment of inertia of the rotor is reduced.
The motor control circuit 26 is a circuit for controlling the motor 12. The motor control circuit 26 includes a semiconductor switch element and the like, and can switch between conduction / interruption of the motor 12 and the battery 28. The motor control circuit 26 operates based on a command from the processing circuit 24, and can adjust the rotational speed of the motor 12 by switching over time the state in which power is supplied / interrupted from the battery 28 to the motor 12.

As shown in FIG. 2, the tightening tool 10 includes a rotary encoder 14 and a torque sensor 18.
The rotary encoder 14 outputs a pulse signal every time the main shaft 16 rotates by a predetermined angle, and the rotation angle of the main shaft can be known from the number of pulses output by the rotary encoder 14. The rotary encoder 14 can be composed of, for example, a magnetic sensor (for example, a Hall element) facing the peripheral side surface of the main shaft 16 and a plurality of magnets provided on the peripheral side surface facing the magnetic sensor.
The torque sensor 18 is a sensor that outputs an electrical signal (voltage) corresponding to the torque acting on the main shaft 16. For example, the torque sensor 18 can be configured by arranging the main shaft 16 so that the magnet and the magnetic sensor face each other. When torque acts on the main shaft 16 and distortion occurs in the main shaft 16, the magnetic permeability of the main shaft 16 changes based on the inverse magnetostriction effect. By detecting the magnetic permeability with a magnetic sensor, the torque value acting on the main shaft 16 can be known. In addition, what employ | adopted various systems is provided for the rotary encoder 14 and the torque sensor 18, and they can be utilized suitably.
The trigger switch 22, the torque setting switch 32, the rotary encoder 14, and the torque sensor 18 are connected to a processing circuit 24 described later, and their output signals are input to the processing circuit 24.

As shown in FIG. 2, the clamping tool 10 includes a processing circuit 24 that performs processing for controlling the operation of the clamping tool 10, a memory circuit 30 that stores various data, and external and electronic information. A transmission / reception circuit 34 for transmitting and receiving is provided. The memory circuit 30 and the transmission / reception circuit 34 are connected to the processing circuit 24, and the memory circuit 30, the transmission / reception circuit 34 and the processing circuit 24 are configured to be able to exchange electronic information.
The processing circuit 24 can calculate the torque applied to the screws by the main shaft 16 (hereinafter referred to as the output torque of the tightening tool 10) from the output signal of the torque sensor 18. The processing circuit 24 stores a relational expression between the output signal of the torque sensor 18 and the output torque of the tightening tool 10, and calculates the output torque of the tightening tool 10 based on the output signal of the torque sensor 18.
The processing circuit 24 includes a pulse counter that counts the output pulses of the rotary encoder 14, and can calculate the rotation angle, rotation speed, and the like of the main shaft 16 based on the value of the pulse counter.
The processing circuit 24 can calculate the set tightening torque based on the output voltage of the torque setting switch 32.

The memory circuit 30 is a non-volatile storage circuit for recording electronic information. The memory circuit 30 stores, for example, calibration coefficient data, usage count data, tool data, and the like.
The calibration coefficient data describes one value k, for example. Hereinafter, this value k is referred to as a calibration coefficient. As described above, the processing circuit 24 stores a relational expression between the output signal of the torque sensor 18 and the output torque of the tightening tool 10. This relational expression is determined when the tightening tool 10 is designed. However, the relationship between the output signal of the torque sensor 18 and the output torque of the tightening tool 10 gradually changes due to deterioration and changes over time due to the use of the tightening tool 10, and the time when the tightening tool 10 is manufactured (design time). ), The torque actually output by the tightening tool 10 cannot be obtained correctly. That is, an error occurs between the output torque calculated from the relational expression stored in the processing circuit 24 and the actual output torque of the tightening tool 10. The calibration coefficient k is an index describing this error. That is, if the output torque calculated from the relational expression stored in the processing circuit 24 is corrected by the calibration coefficient k, the output torque of the tightening tool 10 can be obtained correctly.
The calibration coefficient data is stored in an update as needed during the process of using the tightening tool 10. As will be described in detail later, the calibration coefficient data is obtained by the management device 50 and updated by the management device 50.
As the calibration coefficient k, for example, a quotient obtained by dividing the actual output torque of the tightening torque 10 by the output torque calculated from the relational expression stored in the processing circuit 24 can be used. In this case, the calibration coefficient k of the new tightening tool 10 (that is, at the time of design) is 1.

The use frequency data is data describing the cumulative number of times that the tightening tool 10 has tightened the screws, and is an index indicating the degree to which the tightening tool 10 has been used. The use count data is updated by the processing circuit 24 every time the tightening tool 10 is used.
The tool data describes identification information for identifying the tightening tool 10 from other tightening tools. For example, in the tightening tool 10 of the present embodiment, information “tool ID: MK0910” is described.

The transmission / reception circuit 34 can transmit, for example, use count data, tool data, and the like stored in the memory circuit 30 to the management device 50 based on a command from the processing circuit 24. The transmission / reception circuit 34 can receive calibration coefficient data transmitted from the management device 50. The transmission / reception circuit 34 can receive an information request signal transmitted from the management device 50.
The transmission / reception circuit 34 may transmit / receive electronic information by wire, or may transmit / receive electronic information wirelessly. The transmission / reception circuit 34 of this embodiment transmits and receives electronic information wirelessly.

The operation of the tightening tool 10 will be described. The flowchart of FIG. 8 shows the flow of operations when the tightening tool 10 tightens screws.
When an operator who uses the tightening tool 10 engages the engaging member 20 of the tightening tool 10 with the head of the screw and operates the trigger switch 22, the flow shown in FIG. 8 starts. At this time, the operator sets the tightening torque in advance using the torque setting switch 32.
When the trigger switch 22 is turned on (Yes in step S2), the set value of the tightening torque is calculated from the output signal of the torque setting switch 32 in step S4.
In step S6, the processing circuit 24 instructs the motor control circuit 26 to drive the motor 12. The main shaft 16 is rotated by the rotation of the motor 12, and the screws are tightened.
In step S8, a torque value is calculated from the relational expression between the output signal of the torque sensor 18 and the output signal of the torque sensor 18 stored in the processing circuit 24 and the output torque.
In step S10, the torque value calculated in step S8 is corrected using calibration coefficient data. This corrected torque value is a measured value of the output torque of the tightening tool 10 measured by the tightening tool 10.
In step S12, the tightening torque set value (set torque value) calculated in step S4 is compared with the output torque value obtained by correction in step S8. When the output torque value is smaller than the set torque value (in the case of no), the process returns to step S8, and the processes of step S8 to step S12 are repeated until the answer becomes YES in step S12. If yes in step S12, the process proceeds to step S14.
In step S14, the processing circuit 24 instructs the motor control circuit 26 to stop the motor 12. With the above operation, the tightening tool 10 tightens the screws with the set tightening torque.
In step S16, the processing circuit 24 rewrites the use count data stored in the memory circuit 30 so that 1 is added. When an operator or the like who has confirmed that the operation of the motor 12 has stopped, turns off the trigger switch 22 (YES in step S18), the processing flow by the processing circuit 24 ends.
The tightening tool 10 measures the rotation angle of the main shaft 16 based on the output signal of the rotary encoder while performing the above-described tightening operation. The processing circuit 24 gives a command to the motor control circuit 12 based on the measured rotation angle of the main shaft 16. The processing circuit 24 can also store the measured output torque and the measured rotation angle in the memory circuit 30.

  As described above, the tightening tool 10 compares its output torque with the set torque, and controls the motor 12 to tighten the screws. The tightening tool 10 includes an output signal of the built-in torque sensor 18, a reference relational expression describing the reference relation (initial relation) of the output torque of the tightening tool 10, and calibration coefficient data for calibrating the reference relational expression. Is remembered. This calibration coefficient data is stored so that it can be updated at any time during the process of using the tightening tool 10. Thereby, the tightening tool 10 continues to correctly grasp the relationship between the output signal of the torque sensor 18 and the output torque of the tightening tool 10. Even if the tightening tool 10 is deteriorated in the course of use, for example, its own output torque can be correctly measured, and the screws can be correctly tightened with the set tightening torque.

Next, the management device 50 will be described. As shown in FIG. 1, the brake unit 60 of the management device 50 includes a case 61, a bearing device 67 fixed to the case 61, an inspection shaft 66 rotatably supported by the bearing device 67, and an inspection. An engagement protrusion 70 formed at the end of the shaft 66 is provided.
The engagement protrusion 70 is formed in a shape imitating the head of a screw and is formed so as to be engageable with the engagement member 20 of the tightening tool 10. Thus, the inspection shaft 66 can be rotated by the tightening tool 10 in the same manner as when screws are tightened by the tightening tool 10.

  As shown in FIG. 2, the brake unit 60 includes a brake mechanism 62 that applies a braking torque to the inspection shaft 66, a brake control circuit 76 that controls the operation of the brake mechanism 62, and a rotary that detects the rotation angle of the inspection shaft 66. An encoder 64 and a torque sensor 68 that detects torque acting on the inspection shaft 66 are provided. In addition, a transmission / reception circuit 74 for transmitting and receiving electronic information wirelessly, an input / output circuit (I / O) 78 connected to the computer 90 via a communication cable 88, and the like are provided. The brake control circuit 76, the rotary encoder 64, the torque sensor 68, the transmission / reception circuit 74, and the like are connected to the I / O 78.

The brake mechanism 62 is a mechanism that applies a braking torque to the inspection shaft 66. The braking torque is a torque that acts in a direction that prevents the rotation of the inspection shaft 66 when it rotates, and acts in a direction that keeps the inspection shaft 66 stopped when the inspection shaft 66 is stopped. The brake mechanism 62 increases or decreases the braking torque applied to the inspection shaft 66 based on a command from the brake control circuit 76. As the brake mechanism 62, for example, a friction brake mechanism that presses a friction material against the inspection shaft 66, or a magnetic fluid brake (magnetic fluid clutch) can be employed.
The brake control circuit 76 is a circuit that gives a command to the brake mechanism 62 and controls the operation of the brake mechanism 62.

  The transmission / reception circuit 74 of the brake unit 60 can transmit calibration coefficient data or the like to the transmission / reception circuit 34 of the tightening tool 10, for example. Further, the transmission / reception circuit 74 can receive the use frequency data, tool data, and the like transmitted from the tightening tool 10. The transmission / reception circuit 74 can also transmit an information request signal for requesting transmission of information to the transmission / reception circuit 34 of the tightening tool 10. The transmission / reception circuit 74 may be a circuit that transmits / receives electronic information by wire, or a circuit that transmits / receives electronic information wirelessly. The transmission / reception circuit 74 of this embodiment transmits and receives electronic information wirelessly.

  As shown in FIGS. 1 and 2, the computer 90 of the management device 50 includes a CPU 94 that performs various arithmetic processes, a RAM 96 that is used as a work memory when the CPU 94 performs arithmetic processes, a brake unit 60, and a communication cable 88. Etc., a keyboard 99 for the user to teach information to the computer 90, a display device 98 for the computer 90 to display information to the user, and the like. The computer 90 also includes a storage device 100 that stores data, programs, and the like used by the CPU 94 for arithmetic processing. The storage device 100 is a hard disk drive device built in the computer 90.

The storage device 100 of the computer 90 stores data such as torque-angle data 102 and tool management data 104.
The torque-angle data 102 indicates the angle at which the screws are rotated when the screws are rotated and screwed into a member to be tightened (hereinafter referred to as a base material), and the screws screwed up to the rotation angle. Further, it is data describing the relationship of torque required for screwing.
FIG. 3 illustrates the relationship between the rotation angle and torque described by the torque-angle data 102 (hereinafter referred to as torque-angle information). As shown in FIG. 3, the torque-angle information can be displayed in a graph in which the horizontal axis is the rotation angle θ and the vertical axis is the torque T.
FIG. 3A shows torque-angle information of a tightening portion (so-called hard joint) composed of a relatively hard (highly elastic) base material and screws, and FIG. 3B shows a comparison. Torque-angle information of a tightening part (so-called soft joint) composed of a base material and screws that are soft and soft (low elasticity).

In the case of the hard joint shown in FIG. 3A, in the range of the rotation angle θ from zero to θ1, the torque T gradually increased from zero, and the screws started to engage with the screw holes of the base material. Is shown. When the rotation angle θ is in the range of θ1 to θ2, the torque T is small and substantially constant, and the screws are screwed into the screw holes of the base material until the heads of the screws are seated on the base material. Is shown. When the rotation angle θ is in the range of θ2 to θ3, the torque T increases rapidly, and when the rotation angle θ is θ2, the heads of the screws are seated on the base material until the rotation angle θ reaches θ3 ( This shows that the screws are fastened to the base material (until the torque T reaches T1). In this case, the tightening torque is T1.
In the case of the soft joint shown in FIG. 3B, the range of the rotation angle θ from zero to θ1 and the range of the rotation angle from θ1 to θ2 are substantially equal to the hard joint shown in FIG. When the rotation angle θ is in the range from θ2 to θ4, the torque T gradually increases. When the rotation angle θ is θ2, the heads of the screws are seated on the base material and the rotation angle θ becomes θ4. It shows that the screws are fastened to the base material (until the torque T reaches T1). That is, as in the case of the hard joint shown in FIG. 3A, the tightening torque in the case of the soft joint shown in FIG. 3B is also T1.
As well shown in FIGS. 3 (a) and 3 (b), there is no significant difference in torque-angle information between the hard joint and the soft joint until the screws are seated (the rotation angle is θ2 or less). can not see. On the other hand, after the screws are seated (the rotation angle is θ2 or more), a significant difference can be confirmed between the hard joint and the soft joint. As apparent from FIGS. 3A and 3B, the hard joint has a larger torque value increment relative to the rotation angle increment.
When tightening screws using the tightening tool 10, the actual tightening torque may not be the same when the soft joint is tightened and the hard joint is tightened even if the set torque is set to the same value. Are known. This is due to the difference in torque-angle information between the hard joint and the soft joint. When the torque-angle information is different, the rotational speed of the spindle 16 and the motor 12 of the tightening tool 10 is also different. This is because the influence of the moment of inertia of the spindle, the motor, etc. on the output torque changes. Therefore, in order to manage the tightening torque of the tightening tool 10 and manage the tightening torque of the tightening part, the tightening part is tightened when measuring the output torque of the tightening tool 10. It is preferable to operate the tightening tool 10 in the same manner as sometimes.
The torque-angle data 102 describes a plurality of torque-angle information of various tightening parts. For example, torque-angle information for tightening a bolt for assembling the engine to the vehicle body is described. Each torque-angle information is assigned a torque-angle pattern ID for distinguishing it from other torque-angle information. For example, a torque-angle pattern ID “ENG005” is assigned to the torque-angle information shown in FIG.

The tool management data 104 describes various information related to a plurality of tightening tools 10 groups in association with identification information (tool ID) of the tightening tools 10, and each piece of information related to the plurality of tightening tools 10 groups. Are managed for each tightening tool 10. FIG. 4 illustrates information described in the tool management data 104. FIG. 4 shows information 104a of the tightening tool 10 whose identification information is “tool ID: MK0910”.
As shown in FIG. 4, the tool management data 104 describes the tool ID of the tightening tool 10 such as “tool ID: MK0910” (142 in the figure). Further, the tool management data 104 describes a process in which the fastening tool 10 is used, such as “engine assembly process T line” (144 in the figure). The tool management data 104 describes a torque-angle pattern ID (146 in the figure), for example, “ENG005”. This torque-angle pattern ID corresponds to identification information of torque-angle information described in the torque-angle data 102. The torque-angle information corresponding to the torque-angle pattern ID described in the tool management data 104 describes the torque-angle information of the tightening part tightened by the tightening tool 10. For example, here, torque-angle information of a bolt for assembling the engine to the vehicle body is described.

As shown in FIG. 4, the tool management data 104 includes the date and time (148 and 150 in the figure) when the tightening tool 10 is inspected by the management device 50, and the cumulative number of times the tightening tool 10 is used (152 in the figure). ), The output torque Ta (154 in the figure) of the tightening tool 10 measured by the management device 50, the output torque Tb (156 in the figure) of the tightening tool 10 measured by the tightening tool 10, and the calculated calibration coefficient k (158 in the figure), the result J (160 in the figure) of determining the necessity of the calibration processing, the integrated calibration coefficient (162 in the figure) indicating the integrated value of the calibration coefficient, and the like are described.
The tool management data 104 describes discrimination criteria (164 in the figure) for the calibration coefficient k and the integrated calibration coefficient kt. The calibration coefficient discrimination standard describes, for example, a normal range (1 ± k1 in the figure) and a calibratable range (1 ± k2 in the figure) of the calibration coefficient k. The discrimination standard for the integrated calibration coefficient kt describes, for example, an allowable range (1 ± kx in the figure) of the integrated calibration coefficient kt.
From the tool management data 104 shown in FIG. 4, for example, it can be confirmed that the tightening tool 10 has been inspected before the start of work (8:00) and after the end of work (17:00). It can be confirmed from the inspection result before the work start and the inspection result after the work end that the work of the engine assembly process T line on that day has been normally performed.

The storage device 100 of the computer 90 stores a measurement program 106, a calibration program 108, a management program 110, and the like. These programs are programs executed by the CPU 94.
The measurement program 106 is a program for controlling the brake unit 60 and the like and measuring the output torque and the like of the tightening tool 10. The measurement program 106 includes a program for calculating the rotation angle and rotation speed of the inspection shaft 66, that is, the rotation angle and rotation speed of the main shaft 16 of the tightening tool 10 from the output signal of the rotary encoder 64, for example.
The measurement program 106 calculates a torque applied to the engagement protrusion 70 of the inspection shaft 66, that is, an output torque applied to the inspection shaft 66 by the tightening tool 10 from an output signal of the torque sensor 68, for example. Is included.
The measurement program 106 includes a program that gives a command to the brake control circuit 76 based on the calculated rotation angle of the inspection shaft 66 and the calculated output torque of the tightening tool 10.
The measurement program 106 includes a program for instructing the transmission / reception circuit 74 of the brake unit 60 to exchange information with the tightening tool 10. The measurement program 106 can know, for example, information stored in the memory circuit 30 of the tightening tool 10 or a measured value of the output torque of the tightening tool 10 measured by the tightening tool 10.

The calibration program 108 is a program for performing a calibration process on the tightening tool 10 based on information obtained by the process of the measurement program 106 or the like.
The calibration program 108 includes a program for calculating a calibration coefficient based on the output torque of the tightening tool 10 measured by the management device 50 and the output torque of the tightening tool 10 measured by the tightening tool 10. . Specifically, the calibration coefficient k is calculated by dividing the output torque of the tightening tool 10 measured by the management device 50 by the output torque of the tightening tool 10 measured by the tightening tool 10. If the calibration coefficient k is 1, it indicates that the output torque measured by the management device 50 is equal to the output torque measured by the tightening tool 10. If the calibration coefficient k is larger than 1, it means that the output torque measured by the management device 50 is larger than the output torque measured by the tightening tool 10. If the calibration coefficient k is smaller than 1, it indicates that the output torque measured by the management device 50 is smaller than the output torque measured by the tightening tool 10. A larger difference between the calibration coefficient k and 1 indicates that the error between the output torque measured by the management device 50 and the output torque measured by the tightening tool 10 is larger. The calibration coefficient k can be said to be an index indicating an error between the output torque of the tightening tool 10 measured by the management device 50 and the output torque of the tightening tool 10 measured by the tightening tool 10. Since the output torque measured by the management device 50 is the torque actually output by the tightening tool 10, the calibration coefficient k is the degree of measurement error when the tightening tool 10 measures its output torque. It can be said that it is an index showing.
FIG. 5 is a graph showing an example of the relationship between the number of uses N of the tightening tool 10 and the calculated calibration coefficient k. In the graph of FIG. 5, the horizontal axis indicates the number of uses N, and the vertical axis indicates the calibration coefficient k. In the graph of FIG. 5, the calibration coefficient k changes continuously as the number of uses N increases, and the calibration coefficient k changes abruptly when the number of uses N is N2, N4, N6, for example. The situation is shown. The state in which the calibration coefficient k continuously changes indicates that the measurement error when measuring the output torque of the tightening tool 10 increases as the number of uses N of the tightening tool 10 increases. ing. The manner in which the calibration coefficient k is changing rapidly will be described in detail later. However, the management device 50 calibrated the tightening tool 10 to remove the torque measurement error of the tightening tool 10 that has occurred. Is shown.

The calibration program 108 inquires the calculated calibration coefficient k against the calibration coefficient k discrimination standard 164 described in the tool management data 104 to determine whether the tightening tool 10 is normal or abnormal but can be calibrated. And a program for determining whether the level is abnormal and cannot be calibrated. The processing of the calibration program 108 will be described with reference to the graph of FIG. In the graph of FIG. 5, the “normal range” and the “calibratable range” described by the discrimination criterion 164 of the calibration coefficient k are shown. The calibration program 108 determines that the tightening tool 10 is normal if the calculated calibration coefficient k is within the normal range (1−k1 ≦ k ≦ 1 + k1). If the calculated calibration coefficient k is within a calibratable range (1-k2 ≦ k ≦ 1-k1, 1 + k1 ≦ k ≦ 1 + k2), it is determined that the tightening tool 10 is abnormal but is in a calibratable state. . If the calculated calibration coefficient k is not within the above range (k <1-k2, 1 + k2 <k), it is determined that the tightening tool 10 is abnormal and cannot be calibrated. In the case shown in FIG. 5, when the number of times of use is N2 and N6, it is determined that the tightening tool 10 is in an abnormal state but can be calibrated. Further, when the number of uses is N7, it is determined that the tightening tool 10 is abnormal and cannot be calibrated. It should be noted that the determination criterion 164 for the calibration coefficient k may describe a “non-calibrated range” that indicates outside the calibratable range, instead of describing the “calibratable range”.
Even if the calculated calibration coefficient k is within the normal range, the calibration program 108 takes into account the history of the calibration coefficient k described in the tool management data 104, but the tightening tool 10 is abnormal but can be calibrated. Is determined to be in a bad state. For example, as shown in FIG. 5, a predetermined range (1-k1 ≦ k ≦ 1-k1 ′, 1 + k1 ′ ≦ k ≦ 1 + k1) that is separated from the reference value 1 within the normal range is determined. When the calculated calibration coefficient k is within the predetermined range, the history of the calibration coefficient k is inquired, and the calibration coefficient k is continuously within the predetermined range for a predetermined number of times of use (for example, FIG. 5). N3 times to N4 times in the middle) is determined that the tightening tool 10 is abnormal and can be calibrated.

The calibration program 108 includes a program for calculating the integrated calibration coefficient kt. The calibration program 108 multiplies the calculated calibration coefficient k by the latest integrated calibration coefficient kt described in the tool management data 104 to calculate a new integrated calibration coefficient kt.
FIG. 6 is a graph showing an example of the relationship between the number of times the tightening tool 10 is used and the integrated calibration coefficient kt. In the graph of FIG. 6, the horizontal axis indicates the number of uses N, and the vertical axis indicates the integrated calibration coefficient kt. The initial value of the integrated calibration coefficient kt is defined as “1”. FIG. 6 shows how the integrated calibration coefficient kt changes stepwise. Although this will be described in detail later, the integrated calibration coefficient kt of the tool management data 104 is updated only when the clamping tool 10 is subjected to calibration processing, and when the clamping tool 10 is not subjected to calibration processing, the previous calibration coefficient kt is updated. This is because the value is maintained. The integrated calibration coefficient kt is updated with the calibration coefficient k at that time each time calibration processing is performed on the tightening tool 10. The calibration coefficient k when the calibration process is performed indicates the torque measurement error of the tightening tool 10 removed by the calibration process. Therefore, the integrated calibration coefficient kt indicates the torque measurement error of the tightening tool 10 that is cumulatively removed. In other words, this is a torque measurement error that occurs in the tightening tool 10 when no calibration process is performed on the tightening tool 10. As the integrated calibration coefficient kt is different from the initial value 1, the tightening tool 10 inherently generates a torque measurement error with respect to a new state.

The calibration program 108 makes an inquiry about the calculated integrated calibration coefficient kt to the criterion for determining the integrated calibration coefficient kt described in the tool management data 104, and whether or not the tightening tool 10 is allowed to perform the calibration process. Includes a program to determine whether or not The processing of the calibration program 108 will be described with reference to the graph of FIG. The graph of FIG. 6 shows the “calibration allowable range” described by the discrimination criterion for the integrated calibration coefficient kt. If the calculated integrated calibration coefficient kt is within the allowable range (1−kx ≦ kt ≦ 1 + kx), the calibration program 108 determines that it is permitted to perform the calibration process on the tightening tool 10. If the calculated calibration coefficient k is not within the above range, it is determined that it is not allowed to perform the calibration process on the tightening tool 10. In the case shown in FIG. 5, when the number of uses is N2, N4, and N6, it is determined that the tightening tool 10 is in an abnormal but calibratable state. Further, when the number of times of use is N7, it is determined that the tightening tool 10 is in an abnormal and uncalibrated state. In the case shown in FIG. 6, when the number of uses N is N10, it is determined that the calibration process is not allowed for the tightening tool 10.
The calibration program 108 includes a program for instructing the transmission / reception circuit 74 of the brake unit 60 to exchange information with the tightening tool 10. For example, the calculated calibration coefficient k can be taught to the tightening tool 10. . The calibration program 108 performs calibration processing of the tightening tool 10 by teaching the tightening tool 10 the calculated calibration coefficient k. When the calibration program 108 determines that the tightening tool 10 is abnormal but is in a calibratable level, and further determines that the tightening tool 10 is allowed to perform the calibration process, the calibration program 108 tightens the calculated calibration coefficient k. The accessory tool 10 is taught. Specifically, the transmission / reception circuit 74 is instructed to transmit the calculated calibration coefficient k to the transmission / reception circuit 34 of the tightening tool 10.

  The management program 110 is a program for accumulating and managing information obtained when the management tool 50 inspects the tightening tool 10. For example, the management program 110 includes a program for creating the tool management data 104. Further, the management program 110 includes a program for determining and notifying the maintenance timing of the tightening tool 10 from the number of times of use of the tightening tool 10 described in the tool management data 104, for example.

Next, the operation flow of the management apparatus 50 will be described. FIG. 7 is a flowchart showing a flow of operations of the management device 50 when the tightening tool 10 is inspected. The flowchart of FIG. 7A shows the operation flow of the management apparatus 50. The processing of each step is performed by the CPU 94 executing the measurement program 106, the calibration program 108, the management program 110, and the like. The flowchart of FIG. 7B shows the flow of operation of the tightening tool 10 inspected by the management device 50. Hereinafter, the flow of operations when the management device 50 inspects the tightening tool 10 will be described with reference to FIG.
In step S52 shown in FIG. 7A, the transmission / reception circuit 74 of the brake unit 60 transmits an information request signal to the transmission / reception circuit 34 of the tightening tool 10. In response to the information request signal, the tightening tool 10 transmits tool data, usage count data, and the like from the transmission / reception circuit 34 (step S102 in FIG. 7B).
In step S54, the transmission / reception circuit 74 of the brake unit 60 receives the tool data, the usage count data, and the like transmitted from the transmission / reception circuit 34 of the tightening tool 10. Data received by the transmission / reception circuit 74 is transferred to the computer 90 via the communication cable 88 or the like. The computer 90 reads the tool ID of the tightening tool 10 from the received tool data and identifies the tightening tool 10. Here, “tool ID: MK0910” is read.
In step S56, data corresponding to the tightening tool 10 is read from the tool management data 104 based on the tool ID read in step S54. Here, the tool management data 104a shown in FIG. 4 is read in correspondence with “tool ID: MK0910”.

In step S58, the torque-angle pattern ID is read from the tool management data 104a read in step S56, and torque-angle information corresponding to the torque-angle pattern ID is selected from the torque-angle data 102 and read. The read torque-angle information is stored in the RAM 96. Here, the torque-angle information shown in FIG. 3A is selected in correspondence with the torque-angle pattern ID “ENG005”. The torque-angle information selected here is the torque-angle information of the tightening site where the tightening tool 10 is tightened during normal work.
An inspector who inspects the tightening tool 10 by the management device 50 while the above steps are in progress or at the stage when the above steps are completed, applies the brake to the engaging member 20 of the main shaft 16 of the tightening tool 10. The trigger switch 22 of the tightening tool 10 is operated by engaging with the engaging protrusion 70 of the inspection shaft 66 of the unit 60 (step S104 in FIG. 7B). When the trigger switch 22 is operated, the tightening tool 10 performs the same operation as when tightening screws according to the tightening work flow shown in FIG. The main shaft 16 of the tightening tool 10 rotates the inspection shaft 66 of the brake unit 60. At this time, the brake mechanism 62 applies a substantially constant small braking torque to the inspection shaft 66.
In step S60, it is determined whether or not the rotation speed of the inspection shaft 66 has reached a predetermined rotation speed. The CPU 94 calculates the rotation speed of the inspection shaft 66 based on the value of the pulse counter. When the rotation speed of the inspection shaft 66 reaches a predetermined rotation speed, the process proceeds to the next step S62.

In step S62 of FIG. 7A, the pulse counter that counts the pulse signal output from the rotary encoder 64 is reset. This pulse counter always counts the pulse signal output from the rotary encoder 64, and at the same time it is reset, starts counting the pulse signal again from zero.
In step S <b> 64, the CPU 94 starts a process of calculating the rotation angle of the inspection shaft 66 and the output torque of the tightening tool 10. The CPU 94 calculates the rotation angle of the inspection shaft 66 based on the value of the pulse counter, and calculates the output torque of the tightening tool 10 based on the output signal of the torque sensor 68. When the pulse counter is zero, the rotation angle of the inspection shaft 66 is set to zero. The measured rotation angle and output torque pair data is stored in the RAM 96. Thereafter, the process of measuring and storing the rotation angle and the output torque is repeatedly executed at a predetermined cycle, and an actual measurement value of torque-angle information is created in the RAM 96.
In step S66, the measured rotation angle of the inspection shaft 66 and the output torque pair data of the tightening tool 10 are compared with the torque-angle information selected in step S58. At this time, the rotation angle indicating the seating time in the torque-angle information (here, the angle θ2 in FIG. 3A) is added to the measured rotation angle of the inspection shaft 66. That is, the data of the pair of the measured rotation angle of the inspection shaft 66 and the output torque of the tightening tool 10 is compared with the data after the seating of the torque-angle information (angle θ2 or more).

In step S68, based on the comparison result in step S66, a command is given to the brake control circuit 76 so that the relationship between the measured rotation angle and the output torque is the relationship described in the torque-angle information. In response to the command, the brake control circuit 76 controls the operation of the brake mechanism 62, and the braking torque applied to the inspection shaft 66 is increased or decreased. For example, when the measured output torque is smaller than the value described in the torque-angle information, the braking torque applied to the inspection shaft 66 is increased. When the measured output torque is larger than the value described in the torque-angle information, the braking torque applied to the inspection shaft 66 becomes small. As a result, the tightening tool 10 operates in the same manner as during normal tightening work (here, work for tightening a bolt for assembling the engine to the vehicle body).
In step S70, it is determined whether the inspection shaft 66 is rotating or stationary. If the inspection shaft 66 is rotating (No), the process returns to Step S66. If the inspection shaft 66 is stationary (Yes), the process proceeds to step S72.
The relationship between the rotation angle of the inspection shaft 66 (that is, the rotation angle of the main shaft 16 of the tightening tool 10) and the output torque of the tightening tool 10 by the processing in steps S66 to S70 is the torque-angle information selected in step S58. To be equal to the relationship of Thereby, the relationship between the rotation angle of the main shaft 16 of the tightening tool 10 and the output torque becomes equal to that during normal tightening work, and the tightening tool 10 operates in the same manner as during normal tightening work.
When the inspection shaft 66 stops, the inspector operating the tightening tool 10 turns off the trigger switch 22 (step S110 in FIG. 7B).

In step S <b> 72, an information request signal is transmitted from the transmission / reception circuit 74 of the brake unit 60 toward the transmission / reception circuit 34 of the tightening tool 10. Upon receiving this information request signal, the tightening tool 10 transmits output torque information from the transmission / reception circuit 34 (steps S112 and S114 in FIG. 7B). The output torque information here is a measured value of the output torque calculated by the tightening tool 10 using the calibration coefficient data. The output torque information may describe all the output torque measured by the tightening tool 10, but it is sufficient if it describes the maximum value of the measured output torque. The maximum value of the output torque corresponds to the tightening torque when the screws are tightened.
In step S74, the output torque information transmitted from the transmission / reception circuit 34 of the tightening tool 10 is received by the transmission / reception circuit 74 of the brake unit 60. The management device 50 extracts the maximum value of the output torque from the output torque information, and detects the tightening torque measured by the tightening tool 10.
In step S76, the maximum value is extracted from the measured value of the output torque accumulated and stored in the RAM 96. That is, the tightening torque of the tightening tool 10 measured by the management device 50 is specified. Then, the calibration coefficient k is calculated by dividing the tightening torque measured by the brake unit 60 by the tightening torque measured by the tightening tool 10.

  In step S78, it is determined whether or not the calibration coefficient k calculated in step S76 is within the normal range. The normal range of the calibration coefficient k is described in the tool management data 104. If the calibration coefficient k is within the normal range, the value of the output torque of the tightening tool 10 and the measured value of the output torque of the tightening tool 10 are in good agreement. That is, the tightening tool 10 can accurately grasp its own output torque. In this case, the tightening tool 10 is in a normal state, and it can be determined that the screw can be tightened with a predetermined tightening torque with high accuracy. On the other hand, if the calibration coefficient k is not within the normal range, there is an unacceptable error between the output torque value of the tightening tool 10 and the measured value of the output torque of the tightening tool 10 itself. In other words, the tightening tool 10 recognizes its output torque including an unacceptable error. In this case, in this case, it can be determined that the tightening tool 10 is in an abnormal state and the screws cannot be tightened with a predetermined tightening torque with high accuracy. If the calibration coefficient k is within the normal range (Yes in step S78), the process jumps to step S86. If the calibration coefficient k is not within the normal range (NO in step S78), the process proceeds to step S80.

  In step S80, it is determined whether or not the calibration coefficient k calculated in step S76 is within the calibratable range. The calibratable range of the calibration coefficient k is described in the tool management data 104. In the previous step S78, it is determined that the tightening tool 10 is in an abnormal state. In step S80, the degree of abnormality of the tightening tool 10 is determined. If the calculated calibration coefficient k is within the calibratable range, the error between the output torque value output by the tightening tool 10 and the output torque value measured by the tightening tool 10 is abnormal. The level is not so big. In other words, when the expected deterioration of the tightening tool 10 is taken into consideration, the error is at a predetermined level. In this case, the tightening tool 10 is determined as being in a state in which it can be returned to a normal state by receiving a calibration process. On the other hand, if the calculated calibration coefficient k is not within the calibratable range, the error between the output torque value output by the tightening tool 10 and the output torque value measured by the tightening tool 10 is: The planned level has been exceeded. In this case, the tightening tool 10 is also estimated to be damaged or abnormally deteriorated, for example, and it is determined that the tightening tool 10 is suspected of returning to a normal state even if the calibration process is performed. If the calibration coefficient k is within the calibratable range (Yes in step S80), the process proceeds to step S82. If the calibration coefficient k is not within the calibratable range (NO in step S80), the process jumps to step S86.

In step S82, the integrated calibration coefficient kt is calculated, and it is determined whether or not the calculated integrated calibration coefficient kt is within the allowable calibration range. The allowable calibration range of the integrated calibration coefficient kt is described in the tool management data 104. In the previous step S78, it is determined that the tightening tool 10 is in an abnormal state but can be calibrated. In this step S82, it is determined whether or not the calibration process is allowed to be performed on the tightening tool 10. If the calculated integrated calibration coefficient kt is within the allowable calibration range, even if the tightening tool 10 is subjected to the calibration process, the torque measurement error that is cumulatively removed is not excessive. In this case, it is determined that the tightening tool 10 is allowed to perform the calibration process. On the other hand, if the calculated integrated calibration coefficient kt is not within the allowable calibration range, if the calibration process is performed on the tightening tool 10, the torque measurement error accumulated and removed from the tightening tool 10 is excessive. turn into. That is, the tightening tool 10 inherently generates a large torque measurement error compared to a new state. Therefore, the tightening tool 10 is greatly deteriorated due to use or changes with time. I can judge. In this case, it is determined that the calibration process is not allowed for the tightening tool 10.
If the calculated integrated calibration coefficient kt is within the allowable range of the calibration process (Yes), the process proceeds to step S84. If the calculated integrated calibration coefficient kt is not within the allowable range of the calibration process (No), the process jumps to Step S86.

  In step S84, information describing the calibration coefficient k calculated in step S76 is transmitted from the transmission / reception circuit 74 of the brake unit 60 to the transmission / reception circuit 34 of the tightening tool 10. The transmission / reception circuit 34 of the tightening tool 10 receives the information describing the transmitted calibration coefficient k (step S116 in FIG. 5B). The tightening tool 10 recognizes the calibration coefficient k from the received information, and writes and stores it in the calibration coefficient data of the memory circuit 30. Specifically, the previous calibration coefficient k described in the calibration coefficient data is multiplied by the calibration coefficient k taught in the current examination and stored as a new calibration coefficient k (step S118 in FIG. 5B). . The process of step S84 is a process of calibrating the torque measurement accuracy of the tightening tool 10. The calibration coefficient k stored in the memory circuit 30 of the tightening tool 10 is updated so that the tightening tool 10 can correctly calculate its output torque based on the output signal of the torque sensor 18. become.

In step S86, the inspection results and the like obtained by the above processing are described in the tool management data 104 and stored in the storage device 100. Here, when the calibration process is performed on the tightening tool 10 by the process of step S84, the integrated calibration coefficient kt calculated in the current inspection is employed as the integrated calibration coefficient kt. When the calibration process is not performed, the latest integrated calibration coefficient kt described in the tool management data 104 is adopted. That is, it becomes the same as the integrated calibration coefficient kt at the previous inspection. Since the integrated calibration coefficient kt is updated in this way, the integrated calibration coefficient kt described in the tool management data 104 is equal to the calibration coefficient k stored in the memory circuit 30 of the tightening tool 10.
In step S88, the inspection results and the like obtained by the above processing are displayed on the display device 98 of the computer 90. For example, information described by the tool management data 104 is displayed on the display device 98 of the computer 90. Further, for example, when the calculated calibration coefficient k is within the normal range (Yes in step S78 of FIG. 5A), “Torque measurement accuracy of this tightening tool is normal” is displayed. Also good. If the calculated calibration coefficient k is not within the allowable range for the calibration process (No in step S80 in FIG. 5 (a)), “The torque measurement accuracy of this tightening tool has decreased significantly. Please carry out overhaul, etc. ". Further, when the calculated integrated calibration coefficient kt is not within the allowable range for the calibration process (No in step S82 in FIG. 5A), “the torque measurement accuracy of this tightening tool is the same as when it is new. It has been greatly calibrated in comparison. Check the consumable parts, replace them, and inspect again. ” When calibration processing is performed on the tightening tool 10 (step S84), a message such as “The torque measurement accuracy of the tightening tool has been reduced. The torque measurement accuracy has been calibrated.” Is displayed. Also good.

As described above, the management device 50 inspects the tightening tool 10 and obtains the calibration coefficient k indicating the degree of torque measurement error of the tightening tool 10. By teaching the determined calibration coefficient k to the tightening tool 10, it is possible to remove the torque measurement error occurring in the tightening tool 10 by the tightening tool 10 itself.
When the torque measurement error of the tightening tool 10 is measured, if a torque measurement error exceeding a predetermined level occurs in the tightening tool 10, there is a possibility that some trouble has occurred in the tightening tool 10. There is also a possibility that the accuracy of torque measurement is further rapidly reduced. Even if the calibration process is performed on such a tightening tool 10, the torque measurement accuracy only recovers momentarily. In some cases, the torque measurement accuracy recovered momentarily is trusted, and the tightening tool 10 in which the failure has occurred is continuously used. In the management device 50, when a torque measurement error exceeding a predetermined level occurs in the tightening tool 10, the calibration process is not performed, and the inspector is notified so that the tightening tool 10 is inspected. Prompt. Thereby, for example, the tightening tool 10 in which a failure has occurred is prevented from being used continuously.
When the torque measurement error of the tightening tool 10 is accumulated and largely removed, and a substantial torque measurement error is inherently generated as compared to a new state (design time), for example, deterioration due to use or aging There is a possibility that a change or the like has progressed greatly, and there is a possibility that the torque measurement accuracy increases more rapidly or the torque measurement repeatability decreases. Even if the calibration process is performed on such a tightening tool 10, the torque measurement accuracy only recovers momentarily. The tightening tool 10 having deteriorated may be used continuously because the torque measurement accuracy recovered momentarily is trusted. In the management device 50, when a substantial torque measurement error is inherently generated as compared with a new state (design time), the calibration process is not performed, and the inspector is informed to that effect, and the tightening tool 10 maintenance etc. are encouraged. This prevents the tightening tool 10 having deteriorated from being used continuously.
Based on the calculated calibration coefficient k, the management device 50 performs processing for determining the deterioration state of the tightening tool 10 described above, processing for calibrating the torque measurement accuracy of the tightening tool 10, and the like. Since the management device 50 calibrates the torque measurement accuracy of the tightening tool 10 after determining the deterioration state of the tightening tool 10 and the like, the management device 50 can give high reliability to the torque measurement accuracy of the tightening tool 10. .

  The management device 50 can describe and store information on a plurality of tightening tools 10 groups in the tool management data 104. Accordingly, a tightening tool set can be configured by the plurality of tightening tools 10 group and the management device 50. The torque measurement accuracy of the tightening tools 10 group is maintained by the management device 50. Further, the management device 50 can quickly grasp the abnormality or deterioration state of the tightening tool 10 group. In order to inspect and calibrate each tightening tool 10, it is only necessary to rotate the inspection shaft 66 of the management device 50 with the tightening tool 10, and it is sufficient to perform substantially the same work as one screw tightening work. . In this tightening tool set, the torque measurement accuracy of a large number of tightening tools 10 can be maintained with high reliability. When this tightening tool set is employed in a production site of mass-produced industrial products such as automobiles, for example, high reliability can be imparted to many manufactured industrial products.

In the above description, the case where the relationship between the output torque of the tightening tool 10 and the output signal of the torque sensor 18 changes due to deterioration due to use of the tightening tool 10 or deterioration over time has been described as an example. The relationship between the output torque of the tool 10 and the output signal of the torque sensor 18 varies depending on, for example, the torque-angle information of the tightening part. That is, for example, with the tightening tool 10 adjusted for a hard joint, the soft joint cannot be tightened with a correct tightening torque. Therefore, conventionally, every time the tightening tool is used for another tightening part, it is necessary to remove the torque measuring error of the tightening tool while measuring it. The management device 50 is also effective for this problem. For example, when the production line on which the tightening tool 10 is deployed is changed and is used for a different tightening part, torque-angle information of the tightening part is stored in the torque-angle data 102 to manage the tool. The torque-angle pattern 146 of the data 104 may be rewritten. When the tightening tool 10 is inspected as usual by the management device 50, the calibration coefficient data of the tightening tool 10 is corrected, and the tightening tool 10 is correctly calibrated so as to correspond to the new tightening site.
The tightening tool 10 may employ, for example, a current sensor that detects the current value of the motor 12 instead of the torque sensor 18, and may calculate its own output torque based on the current value of the motor 12. Can also manage such a group of tightening tools 10.

As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, when the management device 50 teaches the calculated calibration coefficient k to the tightening tool 10, it may teach only the calibration coefficient k as in the present embodiment, or a new one with the calibration coefficient k taken into account. A relational expression between the output signal of the torque sensor 18 and the output torque may be taught. In any case, it can be said that the calibration coefficient k is taught. The tightening tool 10 can correctly measure its own output torque by calculating the torque using the taught new relational expression.
The management device 50 may directly input the output of the torque sensor 18 built in the tightening tool 10 when inputting the torque measured on the tightening tool 10 side. The management device 50 stores the relational expression between the output signal of the torque sensor 18 used by the tightening tool 10 and the output torque in advance, or inputs the relational expression from the tightening tool 10, so that the tightening tool 10 side The torque measured with can be known.
In addition, the technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology illustrated in this specification or the drawings achieves a plurality of objects at the same time, and achieving one of the objects itself has technical utility.

The figure which shows the external appearance structure of the clamping tool of an Example, and its management apparatus. The figure which shows the electric structure of the clamping tool of an Example, and its management apparatus. The figure which illustrates torque-angle information. The figure which illustrates the information which the tool management data describes. The figure which illustrates the relationship between the frequency | count of use of a fastening tool, and a calibration coefficient. The figure which illustrates the relationship between the frequency | count of use of a fastening tool, and an integrated calibration coefficient. The flowchart which shows the flow of operation | movement of a management apparatus. The flowchart which shows the flow of operation | movement when a fastening tool fastens screws.

Explanation of symbols

10. Tightening tool 12 .. Motor 16. Spindle 18. Torque sensor 24. Processing circuit 30 Memory circuit 50 Management device 60 Brake unit 62 Brake mechanism 66 Inspection shaft 68 ..Torque sensor 74..Transmission / reception circuit 76..Brake control circuit 90..Computer 94..CPU
100 .. Storage device

Claims (11)

A device for managing a tightening tool having a torque measuring means,
A torque measuring means on the management device side for measuring the torque generated by the tightening tool;
Input means for inputting torque measured by the torque measuring means on the tightening tool side to the management device side;
A calculating means for calculating an index indicating a degree of difference between the torque measured by the torque measuring means on the management device side and the torque measured by the torque measuring means on the tightening tool side;
Teaching means for teaching the tightening tool the index calculated by the calculating means;
A management device comprising: Storage means for storing a predetermined range related to the index is added,
2. The management apparatus according to claim 1, wherein the teaching means does not teach the calculated index to the tightening tool when the calculated index is within the predetermined range.   The management device according to claim 2, wherein the storage unit stores at least a normal range of the index.   4. The management apparatus according to claim 2, wherein the storage unit stores at least an uncalibrated range of the index.   5. The index calculated by the calculating means is a ratio of the torque measured by the torque measuring means on the management device side and the torque measured by the torque measuring means on the tightening tool side. Management device. Accumulation storage means for accumulating and storing an index taught to the tightening tool by the teaching means;
An accumulation index calculation means for accumulating an index group accumulated and stored in the accumulation storage means and calculating an accumulation index;
Second storage means for storing the allowable range of the accumulation index is added,
The teaching means teaches the tightening tool the index calculated by the calculating means only when the accumulated index calculated by the accumulated index calculating means is within an allowable range. Management device. The index calculated by the calculating means is a ratio of the torque measured by the torque measuring means on the management device side and the torque measured by the torque measuring means on the tightening tool side,
7. The management apparatus according to claim 6, wherein the accumulation index calculated by the accumulation index calculation means is a product obtained by multiplying a plurality of ratios accumulated and stored in the accumulation storage means.   The management apparatus according to claim 1, wherein the teaching unit includes a communication unit that can communicate wirelessly and / or with a communication unit included in the tightening tool. A tightening tool having a torque measuring means,
A sensor for detecting an index corresponding to the torque;
Communication means for receiving data used when calculating torque from a detection index of a sensor transmitted from an external device;
Torque calculating means for calculating torque from the detection index of the sensor using data received by the communication means;
Tightening tool comprising A tightening tool having a torque measuring means,
A sensor for detecting an index corresponding to the torque;
Basic relationship storage means for storing the basic relationship between the index and torque detected by the sensor;
Index storage means for storing a correction index transmitted from an external device;
Torque calculation means for calculating torque from the detection index of the sensor, the basic relationship stored in the basic relationship storage means, and the correction index stored in the index storage means;
Tightening tool comprising   A tightening tool set comprising the management device according to claim 1 and the tightening tool according to claim 9 or 10.

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