JP4999480B2 - sewing machine - Google Patents

Description

  The present invention relates to a sewing machine.

  Conventionally, in a sewing machine, a holding base for holding a sewing product and moving it in the XY direction, a stepping motor for moving the holding base, a sensor for detecting whether the holding base is at the origin position, And a control unit that controls the stepping motor based on an input signal from the sensor (see, for example, Patent Document 1). Here, since the sensor has a response speed (self-starting frequency speed), the speed at which the holding table passes over the sensor is set in accordance with the response speed. In other words, the speed of the stepping motor driven at the self-starting frequency speed is a speed at which the stepping motor can reliably stop at the origin position when the holding table is detected by the sensor.

For example, when using an electromagnetic sensor with a response speed of 1 kHz and a stepping motor with a self-starting frequency of 500 PPS and a moving amount of 0.05 mm per pulse, the self-starting frequency speed is 500 PPS × 0.05 mm = 25 mm / s. In order to move 100 mm to the origin position, it took 4 seconds to return to the origin position (100 / (0.05 × 500) = 4 seconds).
Japanese Examined Patent Publication No. 6-102112

In recent years, it has been desired to further shorten the time until return to the origin.
The subject of this invention is improving usability by shortening the time until it returns to an origin.

The sewing machine according to claim 1 is:
A holding stand for holding the sewing product and moving it in the XY direction;
A stepping motor for moving the holding table;
A sensor for detecting whether or not the holding table is at the origin position;
Based on an input signal from the sensor, a control unit that speed-controls the stepping motor to a self-starting frequency speed at which the sensor detects when the holding base is at the origin position and can be stopped immediately;
Of the drive pulse number of the stepping motor for the movement of the holding table after the origin search , add the drive pulse number for the positive direction movement and subtract the drive pulse number for the negative direction movement. And a counter that counts the count value by
The controller is
While subtracting the count value of the counter when searching for the origin, the stepping motor is driven for a predetermined time to accelerate from the self-starting frequency speed to a high frequency speed exceeding the self-starting frequency speed ,
Next, the stepping motor is driven at the high frequency speed until the count value of the counter becomes 0, and after the holding table passes through the point where the count value of the counter becomes 0,
Furthermore, the stepping motor is driven at the self-starting frequency speed until the sensor detects the holding base.

The sewing machine according to claim 2 is the sewing machine according to claim 1 ,
The counter is characterized by continuing to store the count value even when power supply is stopped.

  According to the present invention, since the number of driving pulses of the stepping motor with respect to the movement of the holding table after the previous origin search is counted by the counter, the position where the count value becomes 0 is the approximate origin position. That is, based on the count value of this counter, the holding table can be moved to the vicinity of the origin position. Thereby, it is possible to move to the vicinity of the origin position without considering the response speed of the sensor up to the point where the count value becomes 0, and the stepping motor can be driven at the self-starting frequency speed or higher. In other words, after the stepping motor is driven at the self-starting frequency speed for a predetermined time as in the first aspect of the invention, the stepping motor is driven at a frequency exceeding the self-starting frequency speed until the count value of the counter becomes zero. Until the sensor detects the holding base, or after driving the stepping motor at the self-starting frequency speed for a predetermined time as in the invention of claim 2, The sensor detects the holding base after driving the stepping motor to a count value at which the frequency exceeding the self-starting frequency speed can be decelerated to the self-starting frequency speed before the count value of the counter reaches 0 at a frequency exceeding the speed. It becomes possible to drive the stepping motor at the self-starting frequency speed. If the stepping motor can be driven at a frequency exceeding the self-starting frequency speed, the time until return to the origin is shortened, and usability is improved.

  Further, since the counter continues to store the count value even when the power supply is stopped, the count value obtained by the previous origin search can be reflected even after the power is turned on.

  Hereinafter, the sewing machine according to the present embodiment will be described with reference to the drawings. FIG. 1 is a perspective view illustrating a main configuration of the sewing machine according to the present embodiment. As shown in FIG. 1, the sewing machine 1 includes a sewing machine body 3 that is placed on the upper surface of a sewing machine table 2. At the distal end of the sewing machine arm 4 of the sewing machine body 3, a needle bar 6 that can move up and down that holds the sewing needle 5 and an intermediate presser that moves up and down in synchronization with the raising and lowering of the needle bar 6 and surrounds the periphery of the sewing needle 5. 7 and the needle bar 6 and the intermediate presser 7 are moved up and down by a drive mechanism (not shown) built in the sewing machine main body 3.

The sewing machine 1 also includes a moving mechanism 30 that holds the sewing product and moves it as desired. As shown in FIG. 1, the moving mechanism 30 includes a holding base 31 that is disposed on the sewing machine table 2 and extends below the sewing machine arm 4. That is, the holding table 31 has a tip portion disposed below the sewing arm 4, and the tip portion approaches the vicinity of the sewing needle 5 and the intermediate presser 7 described above disposed on the tip side of the sewing machine arm 4. It is provided in the state of taking out. A mounting plate 41 for mounting a sewing product is connected to the base end portion of the holding table 31.

  The mounting plate 41 is connected at its rear end portion to the lower end on the front side of the base end portion of the holding base 31 described above, and extends along the upper surface of the sewing machine table 2. The front end portion of the mounting plate 41 is formed in a square frame shape, and the sewing needle 5 drops the needle inside the front end portion frame.

In addition, a holding plate 38 formed in a square frame shape having substantially the same size as the mounting plate 41 described above is provided at the tip of the holding table 31.
The pressing plate 38 is disposed above the mounting plate 41, and its rear end portion is attached to the front of the holding table 31 so as to be movable up and down. Thereby, the pressing plate 38 can press and hold the sewn product placed on the placing plate 41. That is, the presser plate 38 holds the sewn product and, along with the driving of the X feed motor 32 and the Y feed motor 33 of the moving mechanism 30 described later, the held sewn product together with the presser plate 38 in the front-rear and left-right directions (XY). Direction).

FIG. 2 is a block diagram showing a main control configuration of the sewing machine according to the present embodiment. As shown in FIG. 2, the control unit 40 of the sewing machine 1 is provided with a CPU 51, ROM 52, RAM 53, and EEPROM 54, and determines whether or not the activation pedal 36 and the holding base 31 to which an activation instruction is input are at the origin position. An origin sensor (sensor) 37 to be detected is electrically connected via input circuits 41 and 42, respectively. The origin sensor 37 is a magnetic proximity sensor, and outputs a detection signal to the control unit 40 when the holding base 31 is at the origin position.
In addition, an operation panel 35 to which various instructions are input is electrically connected to the control unit 40. The control unit 40 includes an X feed motor 32, a Y feed motor 33, which are stepping motors as drive sources of the moving mechanism 30, and a sewing machine motor 34, which is a drive source of the drive mechanism, via drive circuits 43, 44, and 45, respectively. Are electrically connected. The control unit 40 controls the drive circuits 43, 44, 45 based on the input signals from the operation panel 35, the start pedal 36, and the origin sensor 37, and controls the X feed motor 32, Y feed motor 33, and sewing machine motor 34. It is designed to drive. Here, the control unit 40 controls the speed of the stepping motor 34 to the self-starting frequency speed at which the origin sensor 37 detects the origin position and can be stopped immediately.

Here, as the origin search program for returning the holding base 31 to the origin position, three types of origin search programs are prepared and stored in the ROM 52.
When the origin search is performed, the first origin search program drives the X-feed motor 32 or the Y-feed motor 33 for a predetermined time to change from a self-starting frequency speed to a high frequency speed (a frequency speed exceeding the self-starting frequency speed, preferably the origin sensor 37. After that, the holding base 31 is driven at a high frequency speed until it is detected by the origin sensor 37 if it is at the origin position. At the time of detection by the origin sensor 37, the X feed motor 32 or the Y feed motor 33 is driven at a high frequency speed, so that the holding base 31 passes through the origin position. For this reason, in the first origin search program, the position is detected by the origin sensor 37 when the holding base 31 is at the origin position at the point where the self-activation frequency speed is reached while decelerating to the self-activation frequency speed after the origin detection. Thus, the X feed motor 32 or the Y feed motor 33 is driven.

  After the return to origin, the CPU 51 resets the count value based on the number of drive pulses of the X feed motor 32 and the Y feed motor 33 to 0 and stores it in the EEPROM 54. The number of drive pulses of the X feed motor 32 and the Y feed motor 33 with respect to the movement of the holding table 31 after the return to origin is counted by the EEPROM 54. Specifically, when counting the number of drive pulses for movement in the positive direction, it is counted up (addition), and when counting the number of drive pulses for movement in the negative direction, it is counted down (subtraction). . Thus, the EEPROM 54 is a counter according to the present invention.

  In the second and third origin search programs, the origin search is performed based on the count value stored in the EEPROM 54 described above. At this time, even if the holding table 31 is simply returned to a point where the count value becomes 0, there is a possibility that a deviation occurs between the point where the count value becomes 0 and the origin position due to a malfunction such as a motor step-out. is there. In order to eliminate this deviation, the second and third origin search programs perform an origin search based on the count value of the EEPROM 54 and the detection result of the origin sensor 37.

  In the second origin search program, when the origin is searched, the X feed motor 32 or the Y feed motor 33 is driven for a predetermined time to accelerate from the self-starting frequency speed to the high frequency speed, and then the count value of the EEPROM 54 becomes zero. It is designed to be driven at a high frequency. Since the X feed motor 32 or the Y feed motor 33 is driven at a high frequency at the point where the count value is 0, the holding base 31 passes through the point where the count value is 0. For this reason, in the second origin search program, the position is detected by the origin sensor 37 when the holding base 31 is at the origin position at the point where the self-activation frequency speed is reached while decelerating to the self-activation frequency speed after the origin detection. Thus, the X feed motor 32 or the Y feed motor 33 is driven.

  In the third origin search program, when the origin is searched, the X feed motor 32 or the Y feed motor 33 is driven for a predetermined time to accelerate from the self-starting frequency speed to the high frequency speed, and then the count value of the EEPROM 54 becomes zero. After the high frequency speed is driven at a high frequency up to a count value that can be reduced to the self-starting frequency speed, it is driven at the self-starting frequency speed until the origin sensor detects the holding base 31.

  Even after the origin search by the second and third origin search programs, the CPU 51 resets the count value based on the number of drive pulses of the X feed motor 32 and the Y feed motor 33 to 0 and stores it in the EEPROM 54. Therefore, the EEPROM 54 stores a count value reflecting the latest return to origin.

Next, the operation of the sewing machine according to this embodiment will be described.
In the following description, the self-starting frequency is 500 pps, the maximum driving frequency is 10,000 pps, the acceleration / deceleration time (predetermined time) required for acceleration / deceleration from the self-starting frequency to the maximum driving frequency is 0.1 second, and the amount of movement per pulse. A case where the origin search is started from the position where the distance to the origin is 100 mm using the X feed motor 32, the Y feed motor 33 of 0.05 mm, and the origin sensor 37 having a response speed of 1 kHz will be described. Each origin search program is selected by an instruction from the operation panel 35, and the control unit 40 executes the selected origin search program.

First, a case where the first origin search program is executed will be described.
When the first origin search program is executed, the control unit 40 controls the drive circuits 43 and 44 to drive the X-feed motor 32 and the Y-feed motor 33 for acceleration / deceleration time (0.1 second), so that the self-start frequency ( Accelerate from 500 pps to high frequency (10000 pps). At this stage, the holding table 31 has moved by 26.25 mm (movement distance = movement amount per pulse × number of drive pulses required for acceleration from the self-starting frequency to a high frequency = movement per pulse). Amount x acceleration / deceleration time x (self-starting frequency + high frequency) / 2 = (self-starting frequency x amount of movement per pulse + high frequency x amount of movement per pulse) x acceleration / deceleration time / 2 = (self-starting frequency (Speed + high frequency speed) × acceleration / deceleration time / 2 = (0.05 × 500 + 0.05 × 10000) × 0.1 / 2 = 26.25). The self-starting frequency speed is 25 mm / s, and the high frequency speed is 500 mm / s.

  Thereafter, the control unit 40 controls the drive circuits 43 and 44 to drive the X feed motor 32 and the Y feed motor 33 at a high frequency speed until there is a detection signal from the origin sensor 37. Specifically, since it is driven at a high frequency speed by 73.75 mm (− = distance to the origin−moving distance at acceleration = 100 mm−26.25 mm), the origin sensor 37 starts driving at a high frequency speed. The time until the detection signal is 0.1475 seconds (= remaining distance to the origin × movement amount per pulse / high frequency = 73.75 × 0.05 / 10000).

  When the detection signal from the origin sensor 37 is input, the control unit 40 controls the drive circuits 43 and 44 so as to decelerate from the high frequency speed to the self-starting frequency speed, and the X feed motor 32 and the Y feed motor 33. Is driven to pass the holding table 31 with respect to the origin position. The moving time and moving distance at this time are 0.1 second and 26.25 mm as in acceleration, but since the origin sensor 37 has a response speed, 10 pulses (= high frequency in driving at a high frequency speed). / Response speed = 10000/1000). Therefore, in reality, 26.75 mm including 0.5 mm (= 10 pulses × 0.05 mm (movement amount per pulse)) is the movement amount after passing through the origin position, and the response time is 0.001 second ( = 10 pulses / 10000 (high frequency pulse)).

Thereafter, the control unit 40 controls the drive circuits 43 and 44 to drive the X feed motor 32 and the Y feed motor 33 at the self-starting frequency speed until the origin sensor 37 outputs a detection signal. This completes the return to origin. The time at this time is 1.07 seconds (= remaining distance to the origin position / (distance per pulse × self-starting frequency) = 26.75 / (0.05 × 500)).
As a result, the total time from the start to the end of the origin search is 1.4185 seconds (= 0.1 + 0.1475 + 0.1 + 0.001 + 1.07).

  After the return to origin, the CPU 51 resets the count value based on the number of drive pulses of the X feed motor 32 and the Y feed motor 33 to 0 and stores it in the EEPROM 54. The number of drive pulses of the X feed motor 32 and the Y feed motor 33 is counted by the EEPROM 54.

Next, a case where the second origin search program is executed will be described. In this case, the same conditions as in the first origin search program described above are used, but the difference between the point where the count value is 0 and the origin position is −2 mm, that is, the position at the start of the origin search. The distance from the virtual origin (position where the count value becomes 0) is assumed to be 98 mm, for example.
Also, during the execution of the second and third origin search programs, the drive pulses of the X feed motor 32 and the Y feed motor 33 with respect to the movement of the holding base 31 are counted by the EEPROM 54, but approach the origin position. Therefore, the count value is almost always counted down.

  When the second origin search program is executed, the control unit 40 controls the drive circuits 43 and 44 to drive the X-feed motor 32 and the Y-feed motor 33 for a predetermined time (0.1 second), and the self-starting frequency (500 pps). ) To high frequency (10000 pps). At this stage, the holding table 31 has moved by 26.25 mm (movement distance = movement amount per pulse × acceleration / deceleration time × (self-starting frequency + high frequency) /2=0.05×0.1. X (500 + 10000) / 2 = 26.25).

  Thereafter, the control unit 40 controls the drive circuits 43 and 44 to drive the X feed motor 32 and the Y feed motor 33 at a high frequency speed until the count value of the EEPROM 54 becomes zero. Specifically, since it is driven at a high frequency speed by 71.75 mm (− = distance to the virtual origin at the start of origin search−movement distance at acceleration = 98 mm−26.25 mm), it is driven at a high frequency speed. The time from the start until the detection signal of the origin sensor 37 is 0.1435 seconds (= remaining distance to the origin / (movement amount per pulse × high frequency) = 71.75 / (0.05 × 10000) )

  When the count value of the EEPROM 54 becomes 0, the control unit 40 controls the drive circuits 43 and 44 to drive the X-feed motor 32 and the Y-feed motor 33 so as to decelerate from the high frequency speed to the self-starting frequency speed. Then, the holding base 31 is passed with respect to the virtual origin. The moving time and moving distance at this time are 0.1 seconds and 26.25 mm as in the acceleration. That is, if the deviation from the virtual origin -2 mm is added, the remaining distance to the origin position becomes 24.25 mm.

Thereafter, the control unit 40 controls the drive circuits 43 and 44 to drive the X feed motor 32 and the Y feed motor 33 at the self-starting frequency until the origin sensor 37 outputs a detection signal. This completes the return to origin. The time at this time is 0.97 seconds (= remaining distance to the origin position / (distance per pulse × self-starting frequency) = 24.25 / (0.05 × 500)).
As a result, the total time from the start to the end of the origin search is 1.3135 seconds (= 0.1 + 0.1435 + 0.1 + 0.97).

Further, a case where the third origin search program is executed will be described. In this case as well, the same condition as in the case of the first origin search program described above is used, and an explanation will be given by exemplifying a state where there is no deviation where the point where the count value becomes 0 becomes the origin position.
When the third origin search program is executed, the control unit 40 controls the drive circuits 43 and 44 to drive the X-feed motor 32 and the Y-feed motor 33 for a predetermined time (0.1 second), and the self-starting frequency (500 pps). ) To high frequency (10000 pps). At this stage, the holding table 31 has moved by 26.25 mm (movement distance = movement amount per pulse × predetermined time × (self-starting frequency + high frequency) /2=0.05×0.1× (500 + 10000) /2=26.25). The remaining distance to the origin position is 73.75 mm (= 100−26.25).

  Thereafter, the control unit 40 controls the drive circuits 43 and 44 from the high frequency speed to the count value that can be decelerated from the self-starting frequency speed until the count value of the EEPROM 54 becomes 0, and the X feed motor 32 and the Y feed. The motor 33 is driven at a high frequency. The number of drive pulses required to decelerate from the high frequency to the self-starting frequency is 525 pulses (= acceleration / deceleration time × (self-starting frequency + high frequency) /2=0.1× (500 + 10000) / 2 = 525). Therefore, the X feed motor 32 and the Y feed motor 33 can be driven at a high frequency speed until the count value reaches 525. In the present embodiment, a predetermined margin value is provided (for example, 10 pulses) so as to ensure that the self-starting frequency speed is obtained before passing the origin position. Deceleration is started from a point where the count value obtained by adding 10 pulses is 535. The distance from the point where the count value is 535 to the point where the count value is 0 is 26.75 mm (= count value 535 × movement amount per pulse = 535 × 0.05). Therefore, the time for driving at a high frequency speed is 0.094 seconds (= (remaining distance to the origin position−remaining distance from the count value 535) / (movement amount per pulse × high frequency) = ( 73.75-26.75) / (0.05 × 10000)).

When the count value reaches 535, the control unit 40 controls the drive circuits 43 and 44 to drive the X-feed motor 32 and the Y-feed motor 33 so as to decelerate from the high frequency speed to the self-starting frequency speed. The moving time and moving distance at this time are 0.1 seconds and 26.25 mm as in the acceleration. The distance from the completion of deceleration to the origin position is 0.5 mm (= 10 pulse travel distance). From this point, the control unit 40 controls the drive circuits 43 and 44 so that the origin sensor 37 outputs a detection signal. The X feed motor 32 and the Y feed motor 33 are driven at the self-starting frequency until output. This completes the return to origin. The time at this time is 0.02 seconds (= remaining distance to the origin position / (distance per pulse × self-starting frequency) = 0.5 / (0.05 × 500)).
As a result, the total time from the start to the end of the origin search is 0.314 seconds (= 0.1 + 0.094 + 0.1 + 0.02).

  As described above, according to the sewing machine 1 of the present embodiment, the time can be significantly shortened compared with the conventional origin return, regardless of which origin search program is used. Specifically, the search time, which conventionally took 4 seconds under the same conditions, is less than half in any origin search program. This is made possible by driving the X-feed motor 32 and the Y-feed motor 33 at a high frequency speed when searching for the origin. Such shortening improves usability.

Further, since the EEPROM 54 stores the stored contents even when the power supply is stopped, the count value is continuously stored. For this reason, even after the power is turned on, the count value obtained by the previous origin search can be reflected.
Of course, the present invention is not limited to the above-described embodiment and can be modified as appropriate.

It is a perspective view showing the principal part structure of the sewing machine of this embodiment. It is a block diagram showing the main control structure of the sewing machine of FIG.

Explanation of symbols

1 sewing machine 2 sewing machine table 3 sewing machine body 4 sewing machine arm 5 sewing needle 6 needle bar 30 moving mechanism 31 holding base 32 X feed motor (stepping motor)
33 Y-feed motor (stepping motor)
34 Sewing motor 35 Operation panel 36 Start pedal 37 Origin sensor (sensor)
38 Presser Plate 40 Control Unit 41 Mounting Plate 41, 42 Input Circuit 43, 44, 45 Drive Circuit 51 CPU
52 ROM
53 RAM
54 EEPROM (Counter)

Claims (2)

A holding stand for holding the sewing product and moving it in the XY direction;
A stepping motor for moving the holding table;
A sensor for detecting whether or not the holding table is at the origin position;
Based on an input signal from the sensor, a control unit that speed-controls the stepping motor to a self-starting frequency speed at which the sensor detects when the holding base is at the origin position and can be stopped immediately;
Of the drive pulse number of the stepping motor for the movement of the holding table after the origin search , add the drive pulse number for the positive direction movement and subtract the drive pulse number for the negative direction movement. And a counter that counts the count value by
The controller is
While subtracting the count value of the counter when searching for the origin, the stepping motor is driven for a predetermined time to accelerate from the self-starting frequency speed to a high frequency speed exceeding the self-starting frequency speed ,
Next, the stepping motor is driven at the high frequency speed until the count value of the counter becomes 0, and after the holding table passes through the point where the count value of the counter becomes 0,
Further, the stepping motor is driven at the self-starting frequency speed until the sensor detects the holding table. The sewing machine according to claim 1 , wherein
The sewing machine according to claim 1, wherein the counter continues to store the count value even when power supply is stopped.

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