JP2008011971A - Sewing machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To optimize a sewing machine rotation speed and a feed timing when performing XY drive in an optional direction of a cloth pressor by semi-closed loop control. <P>SOLUTION: The sewing machine comprises: a vertical needle movement mechanism; a positioning means having operation amount detection means 76c and 77c for detecting the operation amount of pulse motors 76a and 77a for moving a cloth holding part to an optional position; a thread take-up lever mechanism; a needle location detection means 2b for detecting a needle location in a vertical direction; a pattern storage means 72 for storing sewing pattern data; an operation control means 1000 for outputting command pulses one by one to the pulse motors while maintaining a prescribed deviation from an actual operation; and a required time storage means for storing required time for outputting the command pulses. The operation control means starts the output of the command pulses at the timing of completing the output of the command pulses when a sewing needle 108 reaches an object to be sewn on a needle plate by referring to the required time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a sewing machine having a drive mechanism that moves a cloth holding mechanism to an arbitrary position.

  2. Description of the Related Art Conventionally, an electronic cycle sewing machine that forms a predetermined stitch pattern based on sewing pattern data has been widely used. This electronic cycle sewing machine sequentially refers to the movement amounts in the X and Y axis directions for each needle defined in the sewing pattern data, and the cloth presser for holding the fabric is moved by a pulse motor in the X axis direction and the Y axis direction. A predetermined stitch pattern is formed by driving each needle.

The electronic cycle sewing machine has a case where each pulse motor is driven by open loop control and a case where it is driven by semi-closed loop control.
In the case of a conventional sewing machine that performs sewing with open loop control, the sewing machine's control device has pulled out of the cloth on the needle plate according to the sewing pattern data for each stitch (upper needle position). The command pulses to the pulse motor are sequentially output within the angle range of the upper shaft angle at. At that time, the output timing is adjusted so that the output of the required number of command pulses ends immediately before the sewing needle descends and pierces the fabric (see, for example, Patent Document 1). If the movement of the cloth presser does not end before the sewing needle pierces the cloth, the sewing needle pierced in the cloth will be pulled in the direction of movement of the cloth and will deviate from the needle hole. Such a situation was avoided by adjusting the timing.
In general, the sewing machine is slightly delayed from the top dead center of the sewing needle, the balance reaches the top dead center, and the sewing thread is pulled up. When the cloth movement starts and ends before the sewing thread has been pulled up (before reaching the top dead center of the balance), the sewing thread remaining under the cloth without being pulled up is held by the needle plate. It is sandwiched between the fabrics held by the frame and causes resistance to pulling, and the seam becomes loose. Such a phenomenon has occurred remarkably when the sewing speed at which the cloth movement operation can be performed with sufficient time is slow.
For this reason, as described above, the output timing is adjusted so that the output of the command pulse ends just before the timing when the sewing needle pierces the cloth so that the cloth movement is performed as much as possible after the top dead center of the balance.

  In the open loop control, if the pulse motor is operating in accordance with the drive pulse output timing of the control device, the planned sewing is performed faithfully. However, if the pulse output is increased in order to move the fabric at a high speed, or if the torque load increases due to thick or hard fabric, the pulse output from the control device cannot be tracked and the amount of rotation of the pulse motor is small. There has been a problem of causing a so-called step-out that increases or does not stop.

Therefore, in semi-closed loop control, the pulse motor is equipped with an encoder that outputs pulses according to the amount of rotation, and the deviation between the number of command pulses and the number of detected pulses of the encoder every time a command pulse is output from the control device. The command pulses are sequentially output so that the deviation does not become larger than the set number (see, for example, Patent Document 2).
Pulse motor step-out occurs when the deviation between the number of command pulses and the number of detected pulses from the encoder increases, but the step-out is prevented by delaying the output timing of the command pulses so that the deviation does not increase as described above. ing.
JP 2000-279666 A JP 2004-321771 A

However, in the invention described in Patent Document 2, step-out can be prevented by monitoring a deviation between the number of command pulses and the number of detected pulses of the encoder. Since it fluctuates according to the operating speed, it is impossible to predict the time required to output the number of command pulses to be output with one stitch.
As a result, in the semi-closed loop control, as in the invention described in Patent Document 1, the output timing can be adjusted so that the output of the required number of command pulses ends immediately before the sewing needle descends and pierces the fabric. There wasn't. In other words, in semi-closed loop control, the time required to output the required number of command pulses cannot be predicted, so the timing of command pulse output can be adjusted to end just before the timing when the sewing needle pierces the fabric. There wasn't.
The electronic cycle sewing machine does not detect the motor operation amount of the pulse motor, but detects the actual cloth movement amount in the X-axis direction and the Y-axis direction, and calculates the deviation from the movement amount based on the command pulse. Although it is conceivable to perform closed loop control that performs operation control within a predetermined range, the time required for outputting the required command pulse number cannot be predicted in this case, and the same problem occurs.

  An object of the present invention is to appropriately perform thread pulling by a balance while suppressing the step-out of a pulse motor that performs cloth movement, and to prevent needle bending and needle breakage.

According to the first aspect of the present invention, there is provided a needle up-and-down movement mechanism that moves the sewing needle up and down by rotating the upper shaft, a cloth holding portion that holds the workpiece, and a pulse motor that moves the cloth holding portion to an arbitrary position. A positioning means having an operation amount detecting means for detecting an operation amount of the pulse motor or the cloth holding portion, a balance mechanism for pulling up a sewing thread in conjunction with the needle up / down movement mechanism, and an upper / lower position of the sewing needle. Needle position detecting means for detecting a needle position in the direction, pattern storage means for storing sewing pattern data indicating the operation amount of the cloth holding portion for each needle for a series of sewing operations with a plurality of needle movements, and the sewing pattern data Based on the position data, a command pulse having the number of pulses corresponding to the operation amount for each stitch is output to the pulse motor one pulse at a time while maintaining a predetermined deviation from the output of the operation amount detecting means. Comprising a work control unit, and the required time storage means for storing the required time needed for each of a plurality of operation amounts, and
The operation control means obtains a required time from the required time storage means for each needle of the sewing pattern data, and the timing at which the output of the command pulse is completed when the sewing needle reaches the workpiece on the needle plate. In this case, the output of the command pulse is started.

The needle position detection means may be another configuration that operates in synchronization with the needle, for example, a means that detects the needle position from the rotation angle of the upper shaft or the sewing machine motor.
Further, the operation amount detecting means may detect the operation amount of the pulse motor, or may detect the operation amount of the cloth holding unit.
The sewing pattern data includes information for determining the operation amount of the pulse motor for each of the total number of stitches required for sewing at least for a series of sewing operations (for example, a sewing pattern such as a sewing pattern) using a plurality of needles. include. The information for determining the amount of movement of the pulse motor may be the amount of movement of the pulse motor for each needle itself, or information indicating the target position for each needle in the coordinate system with a fixed origin in position coordinates. May be.

  The invention described in claim 2 has the same configuration as that of the invention described in claim 1, and also includes a period during which the sewing needle is positioned above the workpiece to be sewn on the needle plate and a movement amount for each needle. A configuration is adopted in which speed control means for limiting the rotational speed of the sewing machine motor is provided so that the required time for outputting the command pulse of the corresponding number of pulses is equal to or less than the rotational speed.

  The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and measures the required time when the pulse motor is actually driven by command pulses at individual pulse numbers. The measurement processing means for storing in the required time storage means is provided.

  The invention according to claim 4 has the same configuration as that of the invention according to claim 3, and further includes execution selection means for inputting the selection of execution and non-execution of measurement and storage of the required time by the measurement processing means. The composition is taken.

According to the first aspect of the present invention, when the sewing needle is at a predetermined position in the vertical direction, a command pulse is output from the operation control means in accordance with the operation amount for each needle determined in the sewing pattern data.
The command pulse must be output before the descending sewing needle reaches the sewing product. Even if the command pulse is output at a high speed, the pulse motor does not have the characteristics of the motor itself or the movement of the sewing product. The command pulse cannot be followed according to the torque load for performing the operation, and a step-out may occur.
Therefore, the operation control means outputs the command pulse one pulse at a time, and if it is confirmed that the deviation from the operation amount of the pulse motor detected by the operation amount detection means is maintained within a certain range, the next one pulse The pulse output control is performed to output.
As a result, it is difficult to obtain the required time required to output the command pulse of each pulse number by calculation, but the output required time for each pulse number is stored in the required time storage means. By referring to this, it is possible to recognize the required time for each number of pulses.
Since the required time for outputting the number of pulses required in advance for each hand movement is known from the required time storage means, the timing for starting the output of the drive pulse while monitoring the rotational speed and the needle position by the detection of the needle position detection means By appropriately adjusting, the output of the drive pulse can be completed at a timing immediately before the sewing needle reaches the workpiece.
Thus, for each needle, the cloth can be moved as much as possible from the completion of lifting the balance (top dead center) until the sewing needle reaches the sewing product, and the sewing needle is stuck in the sewing product. It is possible to avoid the movement of the cloth.
Therefore, it is possible to appropriately perform needle drop and thread pulling with a balance at an appropriate position while suppressing the step-out of the pulse motor that moves the cloth, and it is possible to improve the sewing quality.

  According to the second aspect of the present invention, the sewing needle is set to be sewn longer than the time required for the output of the command pulse having the number of pulses corresponding to the movement amount for each stitch determined in the sewing pattern data by the speed control means. Since the rotation speed of the sewing machine motor is controlled so that the sewing machine is positioned above the sewing machine, movement of the sewing product is prevented when the sewing needle is stuck in the sewing product, and the needle drops more accurately. Breaking can be prevented, and the sewing quality can be further improved.

  According to the third aspect of the present invention, since the time required for outputting each pulse number is measured by the actual driving of the cloth holding portion by the measurement processing means, data can be collected during actual sewing work, which is efficient. Furthermore, by executing the measurement while holding the workpiece, it is possible to prepare more accurate data in the required time storage means, and based on this, by driving the pulse motor and performing sewing, It is possible to improve the sewing quality.

  In the invention according to claim 4, it is possible to arbitrarily switch between execution and non-execution of measurement and storage of the required time by the measurement processing means, and it is possible to execute sewing according to various situations.

(Overall configuration of electronic cycle sewing machine)
Embodiments of the present invention will be described with reference to FIGS.
In the present embodiment, an electronic cycle sewing machine will be described as an example of the sewing machine. The electronic cycle sewing machine has a holding frame as a cloth holding portion for holding a cloth that is a sewing object to be sewn, and is held by the holding frame by moving the holding frame relative to the sewing needle. The sewing machine forms a seam on a cloth based on predetermined sewing data (seam pattern).
Here, the direction in which the sewing needle 108 described later moves up and down is the Z-axis direction (up-and-down direction), and one direction orthogonal to this is the X-axis direction (left-and-right direction). The direction perpendicular to the Y axis direction is defined as the Y-axis direction (front-rear direction).

  As shown in FIG. 1, an electronic cycle sewing machine 100 (hereinafter referred to as a sewing machine 100) includes a sewing machine body 101 provided on the upper surface of the sewing machine table T and a pedal provided on the lower part of the sewing machine table T for operating the sewing machine body 101. R and the like.

(Sewing frame and upper shaft)
As shown in FIG. 1, the sewing machine body 101 includes a sewing machine frame 102 whose outer shape is substantially U-shaped in a side view. The sewing machine frame 102 has a sewing machine arm portion 102a that extends above and below the sewing machine body 101, and a sewing machine bed portion 102b that extends below the sewing machine body 101 and extends in the front-rear direction.
The sewing machine body 101 has a power transmission mechanism disposed in a sewing machine frame 102, and has an upper shaft and a lower shaft (both not shown) that are rotatable and extend in the front-rear direction. The upper shaft is disposed inside the sewing machine arm portion 102a, and the lower shaft is disposed inside the sewing machine bed portion 102b.

The upper shaft is connected to a sewing machine motor 2a (see FIG. 3), and rotational power is applied by the sewing machine motor 2a. Further, the lower shaft (not shown) is connected to the upper shaft through a vertical axis (not shown), and when the upper shaft rotates, the power of the upper shaft moves to the lower shaft side through the vertical axis (not shown). The lower shaft rotates.
A needle bar 108a that moves up and down in the Z-axis direction by turning the upper shaft is connected to the front end of the upper shaft, and a sewing needle 108 is connected to the lower end of the needle bar 108a as shown in FIG. Is provided. The upper shaft, the sewing machine motor 2a, the needle bar 108a, and a transmission mechanism (not shown) for applying a driving force for the vertical movement from the upper shaft to the needle bar 108a constitutes a needle vertical movement means.
The needle up / down movement mechanism is also provided with a balance mechanism (not shown). This balance mechanism includes a balance 103 that swings up and down to pull up the sewing thread, and a balance crank that converts the rotational drive of the upper shaft into a reciprocating swing operation and transmits it to the balance 103. In this balance mechanism, the balance 103 is synchronized with the vertical movement of the sewing needle 108 by obtaining the power of vertical swing from the upper shaft to the balance 103. The top dead center of the balance 103 is adjusted so that the phase is slightly delayed from the top dead center of the sewing needle 108 (for example, 60 to 70 °).

  An encoder 2b (see FIG. 3) is provided on the upper shaft. The encoder 2b detects the rotation angle of the upper shaft of the sewing machine motor 2a. For example, the encoder 2b outputs a pulse signal to the control device 1000 every time the upper shaft rotates 1 ° by the sewing machine motor 2a. Further, with one rotation of the upper shaft, the needle bar 108a performs one reciprocating motion. That is, it is possible to detect the needle position in the vertical direction of the sewing needle by detecting the rotation angle of the upper shaft by the encoder 2b, and the encoder 2b functions as a needle position detecting means. In the following description, it is assumed that the sewing needle 108 is set to the top dead center when the upper shaft angle is 0 degree.

A hook (not shown) is provided at the front end of the lower shaft (not shown). When the lower shaft rotates together with the upper shaft, a seam is formed by the cooperation of the sewing needle 108 and the shuttle (not shown).
The connection configuration of the sewing machine motor 2a, the upper shaft, the needle bar 108a, the sewing needle 108, the lower shaft (not shown), the shuttle (not shown) and the like are the same as those conventionally known and will not be described in detail here.

  Further, in order to prevent the cloth from lifting due to the vertical movement of the sewing needle 108, the sewing machine arm 102a moves up and down in conjunction with the vertical movement of the needle bar 108a and presses the cloth around the sewing needle 108 downward. An intermediate press mechanism (not shown) having a presser 29 is provided. Such an intermediate press mechanism obtains the vertical drive force of the intermediate presser 29 from the upper shaft.

  Further, the electronic cycle sewing machine 100 includes a holding frame 111 as a cloth holding portion that holds the cloth to be sewn under the sewing needle 108, an attachment member 113 that supports the holding frame 111, and the attachment member 113. An X-axis motor 76a and a Y-axis motor 77a (see the figure) as pulse motors that move the holding frame 111 to arbitrary positions along the XY plane perpendicular to the vertical movement direction of the sewing needle 108, and the respective X-axis Encoders 76c and 77c (see the figure) as operation amount detecting means for detecting the operation amounts of the motor 76a and the Y-axis motor 77a, and a cloth presser cylinder for moving up and down the holding frame 111 for releasing the cloth via the attachment member 113 (see FIG. And a cloth moving device as positioning means.

The holding frame 111 moves downward to hold the fabric, and moves the held cloth in the front-rear and left-right directions together with the holding frame 111 as the X-axis motor 76a and the Y-axis motor 77a are driven. Then, the movement of the holding frame 111 and the operation of the sewing needle 108 and the hook (not shown) are interlocked to form a stitch based on the stitch data of predetermined sewing pattern data on the cloth.
The holding frame 111 includes a cloth presser (not shown) and a lower plate (not shown), and the attachment member 113 can be driven up and down by driving a cloth presser cylinder disposed in the sewing machine arm 102a. When the cloth presser is lowered, the cloth is held and held between the lower plate and the lower plate.

  The pedal R operates as an operation pedal for driving the sewing machine motor 2a to move the needle bar 108a (the sewing needle 108) up and down and to operate the holding frame 111. That is, the pedal R incorporates, for example, a sensor (depressing amount detecting means) composed of a variable resistor or the like for detecting the depressing operation position when the pedal R is depressed, and an output signal from the sensor is An operation signal of the pedal R is output to a control device 1000 described later, and the control device 1000 is configured to start driving the sewing machine motor 2a in accordance with the operation position and the operation signal.

(Sewing machine control system: overview)
The sewing machine 100 (sewing machine main body 101) has an operation panel 74a for an operator to perform various setting operations on the sewing machine and input operations of various data as shown in FIGS. The operation panel 74a and the sewing machine main body 101 are connected by a wired or wireless line (not shown).
The operation panel 74a includes a plurality of operation key groups capable of various sewing machine settings and various data input operations, a data display unit 74d for displaying various setting states, and the like.
As shown in FIG. 4, the operation panel 74a includes a data display section 74d, a preparation key 74e, a reset key 74f, a + / forward key 74g, a − / reverse key 74h, a pattern number key 74i, an X enlargement / reduction ratio key 74j, There are provided a Y enlargement / reduction ratio key 74k, a speed key 74l, an adjustment mode key 74m, and LEDs 90 and 91 indicating the operation state of the sewing machine and each key.

The data display portion 74d displays the location where the LED 91 is lit, various data numbers corresponding to the keys, data numerical values, and the like.
The preparation key 74e is a key for performing an operation of confirming data or a numerical value changed by the + / forward key 74g or the − / reverse key 74h.
The reset key 74f is a key for performing an operation of resetting data and numerical values changed by the + / forward key 74g, the − / reverse key 74h, and the like.
The + / forward key 74g and − / reverse key 74h are keys for operations for changing various data numbers and data values (forward feed; +, reverse feed; −).
The pattern number key 74i calls, for example, the sewing pattern data 72a corresponding to the sewing pattern in order to select a desired sewing pattern when performing sewing using the sewing pattern data 72a stored in advance. The sewing pattern No. Is a key for displaying. The sewing pattern data 72a will be described later.

The X enlargement / reduction ratio key 74j and the Y enlargement / reduction ratio key 74k are keys for inputting and displaying the enlargement / reduction ratio for the X-axis component and the Y-axis component of the pattern when the sewing pattern is executed. is there.
The speed key 74l is a key for inputting and displaying the setting of the sewing speed at the time of sewing.
The adjustment mode key 74m is a key for switching execution selection between a normal mode and an adjustment mode, which will be described later. Every time the key is pressed, the normal mode and the adjustment mode are switched. The adjustment mode key 74m is used to control the rotational speed of the sewing machine or the time required for the X-axis motor 76a and the Y-axis motor 77a to adjust the output start timing of command pulses to the X-axis motor 76a and Y-axis motor 77a. It functions as an execution selection means for inputting selection of execution and non-execution of measurement and storage.
Various data such as sewing data set and input via various keys on the operation panel 74a is output to the control device 1000 described later and stored in the EEPROM 72 described later.

(Sewing machine control system: control device)
Further, as shown in FIG. 3, the sewing machine 100 includes a control device 1000 as an operation control unit for controlling the operation of each unit and each member described above. The control apparatus 1000 includes a ROM 70, a RAM 71, an EEPROM 72, and a CPU 73 as shown in FIG.

The ROM 70 (PROM) stores a follow-up control program 70a for controlling the sewing machine 100 (sewing machine body 101), a measurement processing program 70b, a speed control program 70c, an output timing adjustment program 70d, and various types of sewing data. Has been.
The RAM 71 is provided with various work memories and counters, and is used as a work area during sewing operations and data processing, and temporarily stores programs and data read from the ROM 70 and the EEPROM 72. .

The EEPROM 72 stores various sewing pattern data 72a, X enlargement / reduction ratio data and Y enlargement / reduction ratio data, sewing speed data, required time table 72b, speed limit table 72c, and output start angle table 72d.
The sewing pattern data 72a is a needle movement pattern for sewing, and data for the X direction movement amount and the Y direction movement amount when moving the holding frame 111 for each needle to execute the needle movement pattern. (Command pulse number) is data that is combined in the sewing order. A plurality of sewing pattern data 72a are prepared in the EEPROM in accordance with various sewing patterns.
At the time of sewing, when the upper axis angle is the data reading timing, the XY movement amount of the sewing pattern data 72a is read, and the number of pulses corresponding to the magnification specified by the X enlargement / reduction ratio key 74j or the Y enlargement / reduction ratio key 74k is X. Command pulses are output to the shaft motor 76a and the Y-axis motor 77a.

  The CPU 73 performs various operation processes, arithmetic processes, and the like based on various programs stored in the ROM 70 using the RAM 71 as a work area (work area).

The CPU 73 is connected to the operation panel 74a via the interface 74, and selects and changes sewing pattern data based on data input from the operation panel 74a.
Further, the CPU 73 is connected to the cloth presser switch 74b and the pedal R via the interface 74. When an instruction signal is input from the cloth presser switch 74b and the pedal R, the CPU 73 performs sewing on the basis of the sewing pattern data described above. Processing for causing each part of 100 to perform sewing is performed.

The CPU 73 is connected to a sewing machine motor drive circuit 75b that drives the sewing machine motor 2a via the interface 75, and controls the operation of the needle up-and-down moving mechanism by controlling the rotation of the sewing machine motor 2a.
The sewing machine motor 2a is provided with an encoder 2b as a needle position detecting means. In the sewing machine motor drive circuit 75b for driving the sewing machine motor 2a, a Z-phase signal output from the encoder 2b for each rotation of the sewing machine motor 2a is received. The CPU 73 can input the origin (0 ° position) in one rotation of the upper shaft by this signal. The encoder 2b inputs an A-phase signal and a B-phase signal output every 1 ° in the rotation angle of the sewing machine motor 2a to the CPU 73 via the interface 75, and the A-phase signal is based on the Z-phase signal described above. By counting the number of pulses of the signal and the B phase signal, the CPU 73 can recognize the current rotation angle and rotation direction of the upper shaft.
For example, a servo motor can be applied to the sewing machine motor 2a.

The CPU 73 also has an X-axis motor drive circuit 76b and a Y-axis motor for driving an X-axis motor 76a and a Y-axis motor 77a provided in the holding frame 111 that holds the cloth to be sewn via the interface 76 and the interface 77, respectively. A drive circuit 77b is connected to control the operation of the holding frame 111 in the X-axis direction and the Y-axis direction.
The X-axis motor 76a and the Y-axis motor 77a are provided with encoders 76c and 77c, respectively, as operation amount detecting means. In the drive circuits 76b and 77b for driving the motors 76a and 77a, the encoders 76c and 77c The Z-phase signal output at each rotation of 76a and 77a is input to the CPU 73 via the interfaces 76 and 77. With this signal, the CPU 73 determines the origin (0 ° position) at each rotation of the motors 76a and 77a. Can be recognized. Also, from each encoder 76c, 77c, the A phase signal and the B phase signal output every 1 ° in the rotation angle of each motor 76a, 77a are input to the CPU 73 via the interfaces 76, 77, and the above-described Z By counting the number of pulses of the A phase signal and the B phase signal based on the phase signal, the CPU 73 can recognize the current rotation angle and rotation direction of the motors 76a and 77a.

  Further, the CPU 73 is connected to an electromagnetic valve driving circuit 79b for controlling the cloth presser cylinder electromagnetic valve 79a for operating the cloth presser motor cylinder 79a via the interface 79, and controls the lifting operation of the cloth presser.

(Sewing machine control system: tracking control program)
The CPU 73 executes the follow-up control program 70a stored in the ROM 70 to output response pulses from the encoders 76b and 77b for each pulse when outputting command pulses to the X-axis motor 76a and the Y-axis motor 77a. The response is monitored, and command pulses are output from the interfaces 76 and 77 while adjusting the output interval so that the deviation between the command pulse and the response pulse does not open more than a predetermined number (for example, 2 pulses). The deviation is set to a limit number of pulses or less that the response pulse cannot be tracked with respect to the command pulse. This prevents the motors 76a and 77a from being stepped out.

(Sewing machine control system: measurement processing program)
The CPU 73 executes the measurement processing program 70b stored in the ROM 70 so that the tracking control program described above is applied to each of the X-axis motor 76a and the Y-axis motor 77a in a state where the adjustment mode is selected. When a command pulse is output based on 70a, the required time is measured, and the required time for each number of pulses is accumulated and recorded. Thus, a required time table 72b indicating the relationship between the number of command pulses and the required output time is generated and stored in the EEPROM 72.
That is, the CPU 73 functions as a measurement processing unit by executing the measurement processing program 70b.
FIG. 5 shows an example of the required time table 72a. The required time table 72b is generated individually for each of the X-axis motor 76a and the Y-axis motor 77a. As shown in the figure, the required time is not calculated for all the pulse numbers, and the required time may be stored for only a part of the number of pulses.

(Sewing machine control system: speed control program)
The CPU 73 executes the speed control program 70c stored in the ROM 70, so that during sewing, the sewing machine motor 2a according to the number of command pulses for each needle for each of the X-axis motor 76a and the Y-axis motor 77a. When the current rotational speed is higher than the limited rotational speed, control is performed to keep the rotational speed of the sewing machine motor 2a below the rotational speed limit.

Here, a method of calculating the rotational speed limit by the speed control program 70c will be described with reference to FIG.
This speed control program 70c is a sewing machine motor so that the period during which the sewing needle 108 is positioned above the cloth on the throat plate 110 does not fall below the time required to output the command pulses for the number of pulses for the target movement amount. This is a program for controlling the rotation speed 2a.
As shown in FIG. 6, in the case of the rotational speed SMn [rpm] of the sewing machine motor 2a, the period of one cycle is 60 / SMn [s]. When a value obtained by multiplying the maximum feed ratio RM set according to the thickness of the fabric is considered as a period in which the sewing needle 108 is positioned above the fabric in one cycle, RM * 60 / SMn [s]. Here, the maximum feed ratio RM is a value that is set and input in advance from the operation panel 74a in accordance with the type of fabric within a range of about 0.4 to 0.6.
In order not to fall below the time required for outputting the command pulses for the number of pulses required for the period in which the sewing needle 108 is positioned above the cloth on the needle plate 110, the time required for the number n of pulses is set to be less. Assuming TMn, RM * 60 / SMn only needs to be equal to or greater than TMn. Therefore, the limiting rotational speed SMn only needs to satisfy the condition of the following expression (1).
SMn ≦ RM * 60 / TMn (1)

Therefore, in the speed control program 70c, when the required time table 72b is generated (or sequentially updated), the number n of command pulses that satisfy the condition of the expression (1) and the limit rotational speed SMn are accordingly generated. The speed limit table 72c showing the relationship is generated individually for each of the X-axis motor 76a and the Y-axis motor 77a. FIG. 7 is a conceptual diagram of the speed limit table 72c. In order to correspond to the thickness of the fabric, the upper axis angle of the holding start of the holding frame 111 and the upper axis angle of the feeding end of the holding frame 111 are adjusted for each maximum feed ratio RM. A relationship with SMn is generated for each maximum feed ratio RM. In the limit speed table 72c, the limit rotation speed SMn is determined in units of 100 [rpm]. However, if the resolution of the sewing machine motor drive circuit 75b can be further subdivided, a more detailed limit rotation speed is obtained for each command pulse number. It may be determined.
At the time of sewing, when the command pulse number n in the X direction and the Y direction is read from the sewing pattern data 72a for each stitch, the lower rotational speed is referenced with reference to the speed limit tables 72c in the X direction and the Y direction. Is determined, and if the current rotational speed exceeds SMn, the rotational speed of the sewing machine motor 2a is controlled to be SMn.
That is, the CPU 73 functions as a speed control unit that limits the rotational speed of the sewing machine motor by executing the speed control program 70c.

(Sewing machine control system: output timing adjustment program)
The CPU 73 executes the output timing adjustment program 70d stored in the ROM 70, so that the sewing needle 108 reaches the cloth on the needle plate 110 for each of the X-axis motor 76a and the Y-axis motor 77a during sewing. At this time, control is performed to start outputting the command pulse at the timing when the output of the command pulse is completed.

Here, a method of calculating the pulse output start timing by the output timing adjustment program 70d will be described with reference to FIG.
The actual rotational speed SCn of the sewing machine motor 2a is determined by the rotational speed SMn determined by the speed control program 70c, the rotational speed determined by the speed key 74l of the operation panel 74a, and the speed of the sewing machine motor that is in accordance with the characteristics of the sewing machine head. The lowest value is adopted among the average rotation speeds.
Therefore, in the case of SCn <SMn, as shown in FIG. 8, the required time TMn for pulse output is longer than the period in which the sewing needle 108 is above the fabric.
In the case of the required time TMn for pulse output at the rotational speed SCn, the following equation (2) is established if the required upper shaft angle angle AFn [°] for pulse output is used.
AFn = 360 * (TMn / (60 / SCn)) (2)
Therefore, if the upper shaft angle at the end of the fabric feed is AE [°], the output upper shaft angle for completing the output of the command pulse when the sewing needle 108 reaches the fabric on the needle plate 110 is represented by the following formula ( ASn [°] shown in 3). The upper shaft angle AE at the end of the fabric feed is set according to the maximum feed ratio RM as shown in the speed limit table 72c described above.
ASn = AE−AFn (3)

Therefore, in the output timing adjustment program 70d, when the required time table 72b and the speed limit table 72c are generated (or updated sequentially), the output required time TMn at each pulse number and the sewing machine motor 2a at each pulse number. The command rotational speed SMn and the actual rotational speed SCn equal to or lower than the limited rotational speed SMn are set according to the formula (3) for each of the minimum rotational speed, for example, 400 [rpm] to the actual rotational speed SCn An output start angle table 72d indicating the relationship between the number of pulses n and the output start upper shaft angle ASn is individually generated for each of the X-axis motor 76a and the Y-axis motor 77a. FIG. 9 is a conceptual diagram of the output start angle table 72d. Since the upper shaft angle of the feed end of the holding frame 111 is determined for each maximum feed ratio RM in order to correspond to the thickness of the fabric, the relationship between the command pulse number n and the output start upper shaft angle ASn is The output start angle table 72d shown is generated for each maximum feed ratio RM. In the output start angle table 72d, the limit rotation speed SMn is determined in units of 100 [rpm]. However, if the resolution of the sewing machine motor drive circuit 75b can be further subdivided, the limit rotation speed is finer for each command pulse number. May be determined.
Further, the actual rotational speed SCn is obtained every time the cloth movement amount is read from the sewing pattern data at the time of sewing without using the table 72c or the table 72d, and from each of the equations (2) and (3), every time the needle is moved. The start timing of the command pulse may be adjusted by calculating the output start upper shaft angle ASn.

(Overall operation description of electronic cycle sewing machine)
Next, the sewing operation of the electronic cycle sewing machine 100 according to the present invention will be described based on the flowchart shown in FIG. The following processing is realized by the CPU 73 executing the above-described programs 70a to 70d, and is repeatedly performed every time the upper shaft angle changes by 1 ° according to the resolution of the encoder 2b of the sewing machine motor 2a. It is what is said.

  First, at the time of sewing when the sewing machine motor 2a of the sewing machine 100 is driven, the encoder 2b determines whether the current upper shaft angle is a position for calculating the cloth movement pulse output start timing (for example, 180 ° in the upper shaft angle). (Step S110). The calculation position of the cloth movement pulse output start timing is set in advance.

  If the upper shaft angle is not the position for calculating the pulse output start timing of the cloth movement, the process proceeds to step S112 (step S110: NO), and if it is the position for calculating the pulse output start timing (step S110: YES). ) For each of the X-axis motor 76a and the Y-axis motor 77a, the output start angle table 72d is referred to, and the output start upper shaft angle ASn is obtained from the number of command pulses and the maximum feed ratio (step S111).

  Next, it is determined whether the current upper shaft angle is the output start upper shaft angle ASn of the X-axis motor 76a obtained in step S111 (step S112). The output start upper shaft angle ASn is specified in advance by the output start angle table 72d.

  When the upper shaft angle is not the output start upper shaft angle ASn of the X-axis motor 76a, the process proceeds to step S115 (step S112: NO), and when it is the output start upper shaft angle ASn (step S112: YES). ), The time when the output of the command pulse to the X-axis motor 76a is started is stored (step S113), and the drive of the X-axis motor 76a is started (step S114).

  Next, it is determined whether the current upper shaft angle is the output start upper shaft angle ASn of the Y-axis motor 77a obtained in step S111 (step S115). The output start upper shaft angle ASn is specified in advance by the output start angle table 72d.

  When the upper shaft angle is not the output start upper shaft angle ASn of the Y-axis motor 77a, the process proceeds to step S118 (step S115: NO), and when it is the output start upper shaft angle ASn (step S115: YES). ), The time when the output of the command pulse to the Y-axis motor 77a is started is stored (step S116), and the drive of the Y-axis motor 77a is started (step S117).

Next, it is determined whether the current upper shaft angle is the sewing machine motor speed switching position (for example, the upper shaft angle is 90 °) (step S118). This sewing machine motor speed switching position is specified in advance.
If the upper shaft angle is not the sewing motor rotation speed switching position, the process proceeds to step S121 (step S121: NO).
If it is the sewing motor rotation speed switching position (step S121: YES), the cloth movement amount of the next needle movement in the X and Y axis directions is read from the sewing pattern data 72a, and the command pulse number of each motor 76a, 77a is read. From the above, the speed limit SMn is specified by the speed limit table 72c. For each of the motors 76a and 77a, the highest among the rotational speeds determined by the limit rotational speed SMn and the speed key 74l of the operation panel 74a and the average rotational speed at the time of acceleration / deceleration of the sewing machine motor according to the characteristics of the sewing machine head. A low speed is selected, which is set as the rotational speed SCn of the sewing machine motor 2a (step S119).
Then, the speed of the sewing machine motor 2a is adjusted to the rotational speed SCn (step S120).

  Next, the CPU 73 determines whether or not the current mode setting is the adjustment mode. If it is not the adjustment mode, the process ends (step S121: NO), and if it is the adjustment mode, the process proceeds to step S122.

In step S122, it is determined whether the output of the command pulse to the X-axis motor 76a is completed. If not completed, the process proceeds to step S124 (NO in step S122).
If the command pulse output has been completed, the elapsed time from the output start time of the command pulse stored in step S113 is obtained, and as a result, the output of the command pulse of the X-axis motor 76a at the number of pulses is required. Time is obtained, and this is overwritten and stored in the required time table (step S123).

In step S124, it is determined whether or not the output of the command pulse to the Y-axis motor 77a has been completed. If it has not been completed, the process ends (step S124: NO).
If the command pulse output has been completed, the elapsed time from the output start time of the command pulse stored in step S116 is obtained, and as a result, the output of the command pulse of the Y-axis motor 77a is required for the number of pulses. Time is obtained, and this is overwritten and stored in the required time table (step S125).
Then, the process ends.

(Effect of electronic cycle sewing machine)
Thus, since the sewing machine 100 according to the present invention includes the required time table 72b indicating the relationship between the number of command pulses and the required output time, the semi-closed loop control is performed on the X-axis motor 76a and the Y-axis motor 77a. , The required time that could not be accurately grasped unless the motor is actually driven can be known from the required time table 72b. As a result, an output start angle table 72d indicating the relationship between the number of command pulses and the output start angle can be generated in advance. The output start angle table 72d allows the sewing needle 108 to determine the output start timing of the drive pulse. The output of the driving pulse can be finished at the timing just before reaching the fabric.
Thereby, for each needle, the cloth can be moved as much as possible from the completion of lifting of the balance 103 (top dead center) to the arrival of the sewing needle 108, and the sewing needle 108 is stuck in the cloth. The movement of the cloth can be avoided.
Accordingly, it is possible to appropriately carry out the needle drop and the thread lifting with the balance 103 at an appropriate position while suppressing the out-of-step of the X-axis motor 76a and the Y-axis motor 77a that move the cloth, thereby improving the sewing quality. It becomes possible.

  Further, in the sewing machine 100, the speed control program 70c is executed by the CPU 73, whereby a speed limit table 72c is generated, whereby a command for the number of pulses corresponding to the movement amount for each stitch determined in the sewing pattern data 72a is generated. Since the rotational speed of the sewing machine motor 2a is controlled so that the sewing needle 108 is positioned above the fabric longer than the time required for outputting the pulse, the movement of the fabric with the sewing needle 108 stuck in the fabric is performed. Thus, needle drop can be performed more accurately, and it is possible to prevent needle breakage and further improve the sewing quality.

  Further, in the sewing machine 100, since the CPU 73 executes the measurement processing program 70b, the time required to output each pulse number can be obtained by the actual driving of the holding frame 111. Therefore, the measurement can be performed while holding the fabric. A more accurate required time table 72b can be generated, and based on this, a speed limit table 72c and an output start table 72d are generated, and the X-axis motor 76a and the Y-axis motor 77a are driven to perform sewing. It becomes possible to aim at the back of the further sewing quality.

  In addition, an adjustment mode key 74m is provided on the operation panel 74, and by selecting the adjustment mode, execution and non-execution of measurement processing can be arbitrarily switched, and sewing according to various situations can be executed. It becomes.

(Other)
Further, the cloth movement may be a driving mechanism such as an arc driving (R-θ system) instead of a mechanism for driving in the XY axis direction.
Further, without providing the speed limit table 72c or the output start angle table 72d, the speed limit of rotation of the sewing machine motor 2a and the output start angle of the pulse may be calculated for each needle.
In addition, it is needless to say that other specific detailed structures can be appropriately changed.

It is a perspective view which shows the sewing machine concerning this invention. FIG. 3 is an enlarged perspective view showing the vicinity of the holding frame and needle bar of the sewing machine according to the present invention. It is a block diagram which shows the control apparatus of a sewing machine. It is a top view which shows the operation panel of a sewing machine. It is a conceptual diagram which shows a required time table. It is explanatory drawing which shows the relationship between a needle position and a command pulse output period. It is a conceptual diagram which shows a speed limit table. It is explanatory drawing which shows the relationship between a needle position and command pulse output start timing. It is a conceptual diagram which shows an output start angle table. It is a flowchart which shows the sewing operation | movement of the sewing machine concerning this invention.

Explanation of symbols

2a Sewing machine motor 2b Encoder (needle position detection means)
70 ROM
70a Tracking control program 70b Measurement processing program 70c Speed control program 70d Output timing adjustment program 71 RAM
72 EEPROM (storage means, intermediate presser height storage means)
73 CPU
74 Adjustment mode key (execution selection means)
76a X-axis motor (pulse motor)
77a Y-axis motor (pulse motor)
76c Encoder (Operation amount detection means)
77c Encoder (Operation amount detection means)
100 electronic cycle sewing machine 108 sewing needle 111 holding frame (cloth holding part)
1000 Control device (operation control means)

Claims (4)

A needle up-and-down movement mechanism that moves the sewing needle up and down by rotating the upper shaft;
A positioning means having a cloth holding part for holding the workpiece, a pulse motor for moving the cloth holding part to an arbitrary position, and an operation amount detecting means for detecting an operation amount of the pulse motor or the cloth holding part; ,
A balance mechanism that pulls up the sewing thread in conjunction with the needle up-and-down movement mechanism;
Needle position detecting means for detecting the vertical needle position of the sewing needle;
Pattern storage means for storing sewing pattern data indicating the operation amount of the cloth holding portion for each needle for a series of sewing operations with a plurality of needles;
Based on the position data of the sewing pattern data, command pulses having the number of pulses corresponding to the operation amount for each stitch are output to the pulse motor one pulse at a time while maintaining a predetermined deviation from the output of the operation amount detection means. Operation control means for
A required time storage means for storing the required time required for each of a plurality of movement amounts;
With
The operation control means obtains a required time from the required time storage means for each operation amount of the sewing pattern data, and the output of the command pulse is completed when the sewing needle reaches the sewing object on the needle plate. A sewing machine that starts outputting the command pulse at a timing.   The rotation speed is equal to or less than the rotation speed at which the period during which the sewing needle is positioned above the workpiece to be sewn on the needle plate and the time required for outputting the command pulse having the number of pulses corresponding to the movement amount for each stitch. The sewing machine according to claim 1, further comprising speed control means for limiting a rotational speed of the sewing machine motor so that   3. A measurement processing means for measuring the required time and storing the required time in the required time storage means when the pulse motor is actually driven by command pulses at individual pulse numbers. Sewing machine.   4. The sewing machine according to claim 3, further comprising execution selection means for inputting selection of execution and non-execution of measurement and storage of the required time by the measurement processing means.

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