JP3357497B2 - Automatic screw tightening machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a torque method tightening control and an angle method tightening control can be arbitrarily selected or combined in accordance with a work at a tightening site so as to perform optimum tightening for the work. The present invention relates to an automatic screwing machine configured as described above.

[0002]

2. Description of the Related Art Conventionally, as a tightening method for tightening a desired work with a predetermined tightening torque, two types of tightening control, a torque method and an angle method, are widely known. Among these tightening controls, the torque method sets a target torque value in advance,
The torque value output from the torque detecting means is compared with the target torque value when the tightening is started, and when the torque values match, the motor is stopped. In the angle method, a target rotation angle of the motor from a fixed position after the start of the tightening is set in advance, and the rotation angle output from the rotation angle detecting means such as an encoder and the target rotation are set when the tightening is started. The motor is stopped by comparing the angles with each other, and when they match, the motor is stopped. This type of tightening control method has both advantages and disadvantages, and it depends on which one is adopted and which combination.
At the stage when the screw tightening machine is manufactured, that is, at the stage when the control software for the screw tightening machine is developed, it is comprehensively determined from the characteristics such as the breaking torque of the screw, the tightening characteristics taking into account the characteristics of the work, and the measured torque values. Have been.

[0003]

Therefore, although this kind of screw tightening machine is provided with an expensive control device for performing the tightening control, the work is changed, and for example, from the tightening of the machine screw to the tightening of the tapping screw. If any of the tightening, such as multi-stage tightening or additional tightening after completion of tightening, is to be performed, select a tightening control method suitable for the new work and install a new control device that performs this tightening control. It must be manufactured or control software changed. For this reason, this kind of screw tightening machine is poor in versatility and unsuitable for multi-kind production, and an automatic screw tightening machine equipped with a control device suitable for multi-kind production is demanded.

The present invention has been made in view of the above-mentioned demands, and a first object of the present invention is to provide an arbitrary number of tightening controls of a torque method tightening control and an angle method tightening control corresponding to a desired work at a tightening site. It is an object of the present invention to provide an automatic screwdriver having a control device capable of selecting or combining methods.

[0005]

[0006]

[0007]

[0008]

Means for Solving the Problems Various screw tightening conditions in each tightening pattern of the torque method tightening control pattern and the angle method tightening control pattern are stored as channel numbers, and the tightening operation is performed by combining the tightening patterns by the number of channel numbers. In an automatic screw tightening machine having a control unit for performing the tightening, each tightening pattern is configured to have a measurement start torque value.

[0009]

[0010]

[0011]

[0012]

[0013]

[Function] In the above automatic screw tightening machine, before starting work
And tighten the actual work until the screw breaks.
To detect the tightening torque characteristics,
Data required for tightening in the desired pattern
Collect and start measuring torque when tightening torque method
Memorize the value and change this data to tighten in multiple stages
For each channel number so that retightening can be performed.
be able to. Therefore, when tightening,
Tightening rule stored for each channel number
Is called and the torque method tightening pattern or angle
The law tightening pattern is selected according to the channel number,
Continuous tightening of channel number without time loss
Can be done. Also, with the torque method tightening pattern
Can select multi-stage tightening or re-tightening
Can be tightened to the workpiece by torque method and angle method
, Multi-stage tightening, and additional tightening
Fastening can be performed with the mounting pattern.

[0014]

[0015]

[0016]

[0017]

[0018]

[0019]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes an automatic screwing machine, which has a driver base 3 that moves up and down by operation of a cylinder 2.
The driver base 3 is configured to be integrally movable with a chuck base 6 to which a chuck unit 5 for guiding a driver bit 4 to be described later is fixed up to a predetermined position, and thereafter the driver base 3 alone can be lowered. A motor 7 and torque detecting means 8 and an encoder 9 positioned above and below the motor 7 are fixed to the driver base 3, and an output shaft 8a of the torque detecting means 8 is fixed.
Is connected to the driver bit 4 via a universal joint 10. The torque detecting means 8 tightens a screw (not shown), and
Is detected as an analog value by a strain sensor (not shown) or a magnetostrictive sensor (not shown) comprising a strain tube (not shown) and a strain gauge (not shown),
This is configured to be output to a control device 11 described later. Further, the encoder 9 is configured to output a rotation pulse to a motor drive unit 13 to be described later as the motor 7 rotates.

The control device 11 of the automatic screwing machine 1 includes:
The control unit 12, the motor drive unit 13, the storage unit 14 for storing various data, the display unit 15 for displaying various input data and the quality of tightening, and the amplifying unit 16a and the calibration unit 16b for analog values from the torque detecting means 8 An A / D converter 16 for converting a digital torque value into a digital torque value via
An operation unit 17 for giving various commands and a cylinder driving unit 18 for driving the cylinder 2 are provided.

The motor drive unit 13 supplies power to the motor 7 in accordance with a speed command value including an initial speed, a maximum speed, and an acceleration, and outputs a rotation pulse from the encoder 9 to the control unit 12. Have been.

The operation unit 17 is provided with a start signal, a setting /
An operation mode selection command signal is output to the control unit 12, and a tightening program number corresponding to a work (not shown) is output from the program selection unit 17a to the control unit 12.

The storage unit 14 stores a measurement start torque value, a speed command value, and a target value necessary for operating a torque method tightening control unit described later from a tightening torque characteristic obtained by actually tightening a desired work until the screw is broken. Data such as a torque value, an upper / lower limit torque value, and an upper / lower limit tightening time is stored for each channel number. In addition, the storage unit also stores a measurement start torque value, a speed command value, a target rotation angle, an upper / lower limit rotation angle, an upper / lower limit torque value, and an upper / lower limit torque value necessary for operating the angle method tightening control unit described later from the tightening torque characteristics. It is configured to store data such as the lower limit tightening time for each channel number. Further, the storage unit 14 changes the data so as to operate the torque method tightening means or the angle method tightening means in accordance with the multi-step tightening and re-tightening pattern, and stores these data in another channel number (for multi-step tightening). , A plurality of channel numbers, and in the case of additional tightening, one channel number).

The storage section 14 stores the tightening torque characteristics,
Select either torque method tightening control or angle method tightening control from the tightening characteristics such as the characteristics of the work, or combine them in any order so that the optimum tightening control for the work can be performed. It is configured to select a tightening pattern and store a channel number corresponding to the tightening pattern together with a program number corresponding to the type of work. The storage unit 14 stores an abnormality processing program having the same abnormality processing program number as the program number, and the abnormality processing program returns the screw corresponding to the tightening abnormality at the time of the i-th channel tightening. An abnormal processing channel number for calling data for performing an abnormal processing operation such as a retightening operation is stored in an (i + 1) th address. Further, the storage unit 14 stores a channel tightening abnormality detection signal output when each tightening program or abnormality processing program is executed together with the type of the abnormality, and inputs the signal from the A / D converter 16 for each channel tightening. It is configured to store the peak torque value of the digital torque value.

Further, the storage unit 14 includes a tightening program for driving the control unit 12, a tightening method registration program,
A torque method tightening control program constituting the torque method tightening control means, an angle method tightening control program, a channel tightening data registration program, and an abnormality processing program constituting the angle method tightening control means are stored.
As shown in FIG. 2, the tightening program reads 1) a setting / operation mode command signal from the operation unit,
In operation mode, jump to 5). 2) Wait for a program registration command signal from the operation unit. If this signal has not been input, jump to 4). 3) Execute the tightening method registration program. 4) Read the setting / operation mode command signal from the operation unit,
In the setting mode, return to 2). 5) Read the tightening start command signal from the operation unit, and if it is not input, return to 1). 6) Output a cylinder drive command signal to the cylinder drive section. 7) Read the tightening program number from the operation unit. 8) Set i = 1. 9) Of the channel numbers stored in the storage unit corresponding to the fastening program numbers, the i-th channel number (C
H number). 10) Determine whether the channel number is the torque method tightening control, and if this is not the torque method tightening control, execute the angle method tightening program and jump to 12). 11) Retrieve the data stored corresponding to the channel number and execute the torque method tightening program. 12) The presence or absence of an abnormality detection signal is determined, and when this is stored in the storage unit, the process jumps to 16). 13) Set i = i + 1. 14) determine whether an i-th channel number (following the channel number) stored corresponding to the program number is stored, and when this is stored,
Return to 9). 15) Output a tightening OK display command signal to the display
Jump to 3). 16) Set i = i + 1. 17) Read the abnormality processing program number corresponding to the program number. 18) It is determined whether there is an i-th abnormal processing channel number in the abnormal processing program number, and if there is no i-th abnormal processing channel number, jump to 22). 19) Retrieve the data stored corresponding to the abnormality processing channel number and execute the abnormality processing program. 20) The presence or absence of a new abnormality detection signal is determined, and when this is stored in the storage unit, the flow returns to 16). 21) When a new abnormality detection signal is not stored in the storage unit, return to 13). 22) Output a fastening failure display command signal to the display unit. 23) Output a return command signal to the cylinder drive unit. 24) Return. It is configured so that

The registration program of the tightening method, as shown in FIG. 3, 1) waits for the input of the tightening program number from the operation unit. 2) Read the tightening program number. 3) i = 1. 4) It is determined whether or not a torque method registration signal has been input from the operation unit. If this signal has not been input, the process jumps to 10). 5) Wait for the input of the channel number for selecting the torque method tightening program. 6) The channel number corresponding to the torque method is stored as the i-th tightening method corresponding to the tightening program number in the storage unit. 7) Set i = i + 1. 8) It is determined whether or not there is a registration completion signal from the operation unit. If this is not input, the process returns to 4). 9) Return. 10) It is determined whether or not an angle method registration signal has been input from the operation unit. If this signal has not been input, the process returns to 8). 11) Wait for the input of the channel number for selecting the angle method tightening program. 12) Store the channel number corresponding to the angle method as the i-th tightening method corresponding to the program number in the storage unit, and return to 8). It is configured so that (Instead of inputting the type information of the torque method control and the angle method control, the torque method and the angle method may be distinguished in advance by the channel number.)

Further, as shown in FIG. 4, the torque method tightening program includes: 1) a measurement start torque value, a target torque value, an upper / lower limit torque value, an upper / lower limit tightening time, and a speed command value corresponding to the channel number. (For example, data suitable for various tightening patterns such as machine screw tightening, tapping screw tightening, multi-step tightening, and additional tightening) are stored for each channel number. ing.). 2) Output a motor drive command signal and a speed command value to the motor drive unit. 3) Read the digital torque value from the A / D converter. 4) Judge whether the torque value has reached the measurement start torque value,
When this does not reach the measurement start torque value, the process returns to 3). 5) Start the tightening time measurement. 6) Read the digital torque value from the A / D converter. 7) It is determined whether the torque value has reached the target tightening torque value. If the torque value has not reached the target tightening torque value, the routine jumps to 14). 8) Output a motor stop command signal to the motor drive unit. 9) The peak torque value is read, and the tightening time measurement is completed. 10) It is determined whether or not this torque value is within the range of the upper and lower limit torque values.
Jump to 7). 11) It is determined whether or not the tightening time has reached the lower limit tightening time. If the tightening time has not reached the lower limit tightening time, the process jumps to 17). 12) Output a channel tightening completion command signal to the display unit (the display unit may display the completion of channel tightening). 13) Output a peak torque value display command signal to the display unit,
Jump to 19). 14) It is determined whether or not the tightening time has reached the upper limit tightening time. If the tightening time has not reached the upper limit tightening time, the process returns to 6). 15) Output a motor stop command signal to the motor drive unit. 16) The peak torque value is read, and the tightening time measurement ends. 17) The channel tightening abnormality detection signal is stored in the storage unit together with the type of abnormality. 18) Output a peak torque value display command signal to the display unit. 19) Return. It is configured as follows.

As shown in FIG. 5, the angle method tightening program includes: 1) a measurement start torque value corresponding to a channel number, a target rotation angle, an upper and lower limit rotation angle, an upper and lower limit tightening time, a speed command value, Recalls data stored in the storage unit such as the lower limit torque value in advance (The storage unit stores data suitable for various tightening patterns such as machine screw tightening, tapping screw tightening, multi-step tightening, and additional tightening for each channel number. It is memorized.) 2) Output a motor drive command signal and a speed command value to the motor drive unit. 3) Read the digital torque value from the A / D converter. 4) Judge whether the torque value has reached the measurement start torque value,
When this does not reach the measurement start torque value, the process returns to 3). 5) Start the tightening time measurement. 6) The counting of the rotation pulses from the encoder is started, and the rotation angle of the motor is calculated. (This rotation angle may be the number of rotation pulses). 7) Judge whether the rotation angle of the motor has reached the target rotation angle,
When this does not reach the target rotation angle, jump to 15). 8) Output a motor stop command signal to the motor drive unit. 9) The peak torque value and the rotation angle are read, and the tightening time measurement is completed. 10) It is determined whether or not this rotation angle is within the range of the upper and lower limit rotation angles, and when the rotation angle is not within the range of the upper and lower limit rotation angles, jump to 18). 11) It is determined whether or not the peak torque value is within the range of the upper and lower limit torque values, and when this is not within the predetermined range, jump to 18). 12) Judge whether the tightening time has reached the lower limit tightening time, and when this does not reach the lower limit tightening time, jump to 18). 13) Output a channel tightening completion command signal to the display unit (the display unit may display the completion of channel tightening). 14) Output a peak torque value display command signal to the display unit,
Jump to 20). 15) It is determined whether or not the tightening time has reached the upper limit tightening time. If the tightening time has not reached the upper limit tightening time, the process returns to 6). 16) Output a motor stop command signal to the motor drive unit. 17) While reading the peak torque value and the rotation angle,
End the tightening time measurement. 18) The channel tightening abnormality detection signal is stored in the storage unit together with the type of abnormality. 19) Output a peak torque value display command signal to the display unit. 20) Return. It is configured as follows.

The channel tightening data registration program, as shown in FIG. 6, 1) waits for an input of a channel number from the operation unit. 2) Read the channel number. 3) Output a data item display command signal to the display unit (each time the display unit receives the data item display command signal, the measurement start torque value, target torque value, target rotation angle, upper / lower limit torque value, upper / lower limit rotation) The angle, the upper and lower limit tightening time, and the motor speed command value are displayed.) 4) Judge whether data has been input from the operation unit. If not, jump to 6). 5) Read the input data corresponding to the channel number. 6) It is determined whether there is a next data item call command signal from the operation unit. When this signal is input, the process returns to 3). 7) It is determined whether or not a new channel number has been input from the operation unit. When the new channel number has been input, the process returns to 2). 8) It is determined whether or not a registration completion command signal has been input, and if it has not been input, the process returns to 4). 9) Return. It is configured so that

The abnormality processing program is configured to use the torque method tightening control or the angle method tightening control according to the content of the abnormality, and the data used at that time is, for example, when a screw is removed. When the speed command value reverses the polarity so as to loosen the screw, and when the screw floating abnormality is to be treated, the target rotation angle is appropriately set so that the screw is forcibly tightened until it is seated on the work ( At this time, means for detecting the seating of the screw is required), and is stored for each abnormality processing channel number dedicated to abnormality processing.

In the above automatic screw tightening machine, prior to the start of work, actual work is tightened until the screw is broken to detect a tightening torque characteristic, and from the tightening torque characteristic, it is necessary to perform tightening in a desired pattern. Collect data. At this time, if the machine screw is tightened by the torque method, the measurement start torque value, the target torque value,
Data such as upper and lower limit torque value, upper and lower limit tightening time, motor speed command value, etc. are collected. Similarly, when the tightening is performed by the angle method, data such as a measurement start torque value, a target rotation angle, an upper and lower limit rotation angle, an upper and lower limit tightening time, a motor speed command value, and an upper and lower limit torque value are collected. These data are stored in the storage section 14 together with the type information of the tightening control for each channel number. Further, if multi-stage tightening and re-tightening are to be performed, the data of the torque method tightening control and the angle method tightening control are changed so that the motor is driven in accordance with these tightening patterns, and these are changed for each channel number. In other words, in the case of multi-stage tightening, a plurality of channel numbers are allocated, and data for performing tightening control in each stage is assigned to each channel number, and in the case of additional tightening, data for performing additional tightening for one channel number is tightened. (Instead of this type information, a channel number may be assigned in advance to a torque method for tightening, an angle method for tightening, a torque method abnormal tightening process, or an angle method abnormal tightening process. ).

When the optimum tightening pattern for the desired work is registered in the storage unit 14 , the setting mode is selected by the setting / operation mode switch (not shown) of the operation unit 17, and the tightening program number is set by the program selecting unit 17a. I do. With the setting of the tightening program number, the address of the storage unit 14 corresponding to the tightening program number is sequentially called, and from the tightening torque characteristics, an optimum tightening pattern is set as a channel number so that optimum tightening is performed when tightening the work. The information is stored singly or in combination with a predetermined number. For example, when performing high-precision tightening with a machine screw, the torque method tightening control data is used.When tightening a tapping screw with a forming screw value larger than the target torque value, the angle method must be used until the internal thread is completely cut. In order to call the tightening data of the tapping screw, then the torque method tightening control data, and when tightening, the tightening control data described above is called and the tightening data by the torque method or the angle method can be called. An arbitrary number of channel numbers are stored.

When an optimum tightening pattern is set for a desired work, an operation mode is selected by a setting / operation mode switch, and a start command signal is output from the operation unit 17 together with a tightening program number corresponding to the desired work. Then, the stored channel number and type information corresponding to the tightening program number are sequentially called. Therefore, various data stored corresponding to the first channel number is called, and the channel is tightened by the torque method tightening control or the angle method tightening control. Thereafter, when the next channel number corresponding to the program number is stored in the storage unit 14, the tightening is continuously performed by the torque method tightening control or the angle method tightening control. For this reason, even if any of the torque method tightening control and the angle method tightening control method are set first, or even in multi-stage tightening control, or even after tightening is completed and additional tightening is performed, Tightening control can be switched without a loss of time, smooth tightening can be performed, and at this time, since the driver bit does not come off from the screw, tightening can be performed under optimum conditions.

In addition, even when the torque method tightening control or the angle method tightening control is performed, even if an error such as no screw or screw floating occurs in the tightening control, an error such as retightening or reverse rotation of the screw. If the processing means is stored in the storage unit as a channel number, these abnormal processes can be continuously and automatically performed.

Further, when a screw floating abnormality occurs by performing the torque method tightening control, if an error processing channel number by the angle method is selected, the screw is forcibly seated on the work by the angle method tightening control. Until it is tightened. In this case, it is necessary to detect the seating of the head of the screw.

In the embodiment, a program number is provided according to the type of work, a channel number is stored according to the program number, and data corresponding to the channel number is sequentially called. If it is limited to one type of work, it is only necessary to store only an arbitrary number of channel numbers and sequentially call them without providing a program number.

[0037]

As described above, the present invention provides a torque method.
Each tightening control pattern and angle method tightening control pattern
Various screw tightening conditions in the mounting pattern
Number and tighten by the number of channel numbers
Control unit that performs tightening operation by combining
For each tightening pattern, the measurement start torque value
Before starting work,
Tighten by tightening the actual work until it breaks
The torque characteristics are detected.
Gather the data needed to tighten in the desired pattern
For torque method tightening, enter the measurement start torque value.
Remember, change this data again and tighten
It can be stored for each channel number so that it can be tightened
it can. Therefore, when tightening work,
On the other hand, the tightening conditions stored for each channel
And torque method tightening pattern or angle method tightening
Is selected according to the channel number.
Tighten the number of tunnels continuously without any time loss
be able to. In the torque method tightening pattern, multi-stage
You can also select floor tightening or retightening,
Workpiece torque method, angle method tightening, multi-stage
Desired tightening pattern combining floor tightening and retightening
Tightening can be done by turns .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the overall configuration of the present invention.

FIG. 2 is a flowchart illustrating a tightening control program according to the present invention.

FIG. 3 is a flowchart illustrating a registration program of a tightening method according to the present invention.

FIG. 4 is a flowchart illustrating a torque method tightening program according to the present invention.

FIG. 5 is a flowchart illustrating an angle method tightening program according to the present invention.

FIG. 6 is a flowchart illustrating a channel tightening data registration program according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automatic screw tightener 2 Cylinder 3 Driver stand 4 Driver bit 5 Chuck unit 6 Chuck stand 7 Motor 8 Torque detection part 8a Output shaft 9 Encoder 10 Universal joint 11 Control device 12 Control part 13 Motor drive part 14 Storage part 15 Display part 16 A / D conversion unit 16a Amplification unit 16b Calibration unit 17 Operation unit 17a Program selection unit 18 Cylinder drive unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-160488 (JP, A) JP-A-6-47635 (JP, A) JP-A-6-79551 (JP, A) 277432 (JP, A) JP-A-59-110519 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23P 19/06

Claims (1)

(57) [Claims] 1. A torque method tightening control pattern, stores the channel number of various screwing conditions in each fastening pattern angle method tightening control pattern, Chang
Tightening in combination with only tightening pattern the number of channel number
In the automatic screw driver including a control unit that performs only operation, each clamping patterns are all having a measurement start torque value
Automatic screwing machine, characterized in that as that.