JPS6057357B2 - Stepping motor stepout correction device for sewing machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention forms a stitch pattern by driving a stepping motor based on stitch information stored in advance in a microcomputer (hereinafter referred to as microcomputer) and setting the needle swing position and cloth feed amount. The present invention relates to a sewing machine in which the present invention is possible, and particularly to a step-out correction device for a stepping motor in a sewing machine.

Conventionally, as an example of a step-out correction device for a stepping motor in a sewing machine, the one described in Japanese Patent Application Laid-Open No. 1120816 is known, and according to this device, the stepping motor step-out correction device is corrected when the power of the sewing machine is turned on and off. We try to compensate for the adjustment, but if the stepping motor loses its synchronization due to, for example, force being applied to the cloth feed dog or needle bar during sewing, it is necessary to adjust the sewing machine to compensate for this. It is necessary to turn the power off once, and for this reason, the power to the pattern selection means is turned off, and the selected pattern is canceled, so the pattern selection operation must be performed again after the power is turned on again. However, the disadvantage was that the work became complicated and work efficiency decreased. The object of the present invention is to overcome the drawbacks of the above-mentioned conventional devices.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. On the front surface of the horizontal arm of the machine frame 1 of the sewing machine, stitch patterns (not shown) are individually displayed, and currently selected patterns are selected by operating the pattern selection switch 3. A pattern display panel 2 provided with display means (not shown) for displaying a pattern is arranged.

A start/stop switch 4 that alternately generates a start/stop signal for the rotation of the main shaft 10 when pressed is provided on the front side of the jaw of the machine frame 1, and a needle bar 9 (see Fig. 2) is provided on the machine frame of the jaw. The needle 5 is fixed to the lower end of the needle bar 9. On bed 6,
The needle hole 8a corresponding to the needle drop point of the needle 5 and the feed dog 12 (second
A needle plate 7 is provided with a long hole 8b for the needle (see figure) to appear and disappear. Further, in FIG. 2, the needle bar 9 is connected to be movable up and down in conjunction with the rotation of the main shaft 10, and also in a direction crossing the cloth feeding direction in conjunction with the swinging of a rod 11 connected to the swing stepping motor SM1. The needle swing position is determined in relation to each step angle of the swing stepping motor SM1. A clutch device (FIG. 3) for transmitting and interrupting the power of the sewing machine motor M (FIG. 11) to the main shaft 10 is loosely fitted to the main shaft 10. This clutch device is shown, for example, in Japanese Patent Application No. 55-100241 filed by the present applicant, and the pulley 16 and main shaft 10 are normally interlocked by the action of the clutch spring 20, but the clutch When the magnet CMG is excited, the stop lever 2
0 engages with the locking portion 18 or 19 to disengage the clutch and the sewing machine stops at the needle up position or needle down position. Further, the feed dog 13 performs a feed motion by four movements in conjunction with a lower shaft 14 connected to the main shaft 10, and also operates a feed stepping motor via a crank 16, a link 15, and a well-known feed amount setting cam mechanism 12. The feed amount is set in relation to each step angle of SM2. Further, a pulse generator (FIG. 4) is arranged in relation to the main shaft 10, which generates timing pulses for obtaining drive timings for each stepping motor and stop pulses for obtaining excitation timings for the clutch magnet CMG.

This pulse generator consists of a magnet 21 fixed to a main shaft 10 and having a large diameter part 21a and a small diameter part 21b, and magnetically sensitive elements 22 and 23 arranged close to the outer peripheral surface of this magnet 21. 22 and 23 generate a logic RHJ signal when facing the large diameter portion 21a, and generate a logic RHJ signal when facing the small diameter portion 21b.
When facing the needle 5, it generates a logic RLJ signal, and the magnetic sensing element 22 generates a needle swing timing signal (H level) in relation to the spindle rotation range where the needle 5 is above the throat plate 1.
The cloth feed timing signal (L level) is arranged to be generated in relation to the lower spindle rotation range, and the magnetically sensitive element 23 is located further forward in the rotational direction of the spindle 10 than the magnetically sensitive element 22. The rising and falling timing of the signal becomes the excitation timing of the clutch magnet/CMG. Swing/feed stepping motor SMl, S
M2 has eight pole teeth f1 to F4, f as shown in FIG.
It is a split type consisting of a stator 27 which has a V-FC and has a plurality of small teeth 26 formed on each pole tooth, and a rotor 24 which has a plurality of teeth 27 formed on its outer peripheral surface. 1-
A two-phase excitation system is adopted, and therefore, each step has a small pitch P as shown in FIG. 7, making it possible to form a fine stitch pattern using the swing/feed stepping motors SM1 and SM2. The rotation range of these stepping motors is limited by a stopper body (not shown) fixed to the rotation shaft, and the rotation within this rotation range is caused by the transition of the excitation state of A-H as shown in Figure 8. move. That is, in this embodiment, the swing stepping motor SMl has a rotation range of 32 steps as shown in FIG. Corresponds to the rightmost side. The rotation range of the feed stepping motor SM2 is 41 steps as shown in Fig. 9. JOJ corresponds to the setting of 0 cloth feed amount, and 1+23J (L origin) and 1-17J correspond to the setting of cloth feed amount, respectively. Supports forward and reverse maximum amount settings. Additionally, these stepping motors include
For example, the step angle detection device using a photosensor is described in Japanese Patent Application Laid-open No. Sho M-120816! Place the ISD (Figure 10). A step angle detection device SD is disposed on the feed stepping motor SM2 so that, in FIG. 11, the rotational position of the feed stepping motor SM2 is such that SD is on when the rotational position of the feed stepping motor SM2 is on the L origin, and SD is off when it is to the right of the L origin. Next, the electric circuit of this embodiment will be explained.

In FIG. 10, MC is a well-known microcomputer having storage, calculation, and input/output functions, and stores in advance needle swing and cloth feed amount information corresponding to each stitch of a plurality of stitch patterns. A sewing machine motor M is connected to the output port of the microcomputer MC via a latch for holding commands from the microcomputer MC and a motor drive circuit MDR, and a swing stepping motor SMl and a feed stepping motor SM2 are connected via a stepping motor drive circuit SDR. and the clutch magnet CMG via the clutch drive circuit CDR. In addition, the output terminals of the clock pulse generator ADl magnetically sensitive elements 22 and 23 for operating the microcomputer MC are connected to the input port, and the pattern selection is further carried out via a buffer for synchronizing the command timing with the operating speed of the microcomputer MC. The switch 3, start/stop switch 4, and step angle detection device SD are connected separately. In the microcomputer MC, one-point mode setting function, buttonhole sewing function, stepping motor step-out correction function, etc. are programmed and stored in advance. ) from 11th to
This will be explained based on the flowchart in FIG.

This flow includes (1) a stop function (■ ) A determination function for determining whether or not to correct step-out of the stepping motor; and (■) an operation function for correcting step-out of the stepping motor, which will be explained in sequence below. 1 Clutch magnet 0FF routine is a routine in which the clutch magnet CMG is deactivated in FIG. 3 to release the engagement between the locking portion 18 or 19 and the stop lever 20.

1 motor low speed signal routine is the speed at which the sewing machine main shaft rotates once when the sewing machine motor M is started, and the stepping motor SM2 can reciprocate through its rotation range (Fig. 9) while the needle is positioned below the throat plate. In other words, in order to make it possible to correct the out-of-step of the feed stepping motor SM2 during one revolution of the main shaft 10, it is set to be driven at a low speed.

Therefore, in FIG. 11, when the start/stop switch 4 is pressed and turned on, if the sewing machine motor M is stopped,
The sewing machine motor M is started through the motor low speed signal routine, and if the sewing machine motor M is rotating, the lower stop flag is set. While the sewing machine motor M is rotating, when the upper stop timing comes, it is determined whether the one-point mode (unit pattern stitching or cycle stitching such as buttonhole stitching) is selected. At this time, if it is not the one-point mode, it is immediately determined whether the upper stop flag is set, and if the upper stop flag is set, the clutch magnet CM is activated in response to the rise of the output signal of the magnetic sensing element 23.
If G is on and in one point mode,
At the final stitch, after the final stitch flag and single stitch flag are set, it is determined whether the upper stop flag is set or not.The upper stop flag is set as shown in Fig. 12. It is only relevant to the setting of the single stitch flag, ie the last stitch flag. Next, while the sewing machine motor is rotating, when the bottom stop timing comes, it is determined whether or not the bottom stop flag is set. Clutch magnet CMG is turned on.

That is, in one point mode, the clutch magnet CMG is turned on near the top stop timing, and if not in the one point mode, the clutch magnet CMG is turned on near the bottom stop timing, and in each case, the clutch magnet CMG is turned on near the bottom stop timing.
will stop at the top or stop at the bottom, but in either case, after the clutch magnet CMG is turned on, 300n1
After S is set in the timer and the sewing machine motor M rotates for this period, it is determined whether the first clutch magnet is on or off because these stop positions are different from the upper and lower stop timings as described above.

At this time, after 300ms of the timer has elapsed, if the sewing machine motor M is rotating, 1500n1s is set in the timer, the clutch magnet CMG is turned on during this period, the power of the sewing machine motor M is turned off, and the sewing machine motor When 1500ms of the timer elapses after the stop of M, the clutch magnet JCMG is moved to the locking portion 18 or 1 by the action of the 1st clutch magnet CMG routine.
9 is released.

(■) Figure 12 is a flow that continues from Figure 11, where 1 pulse timer means one pulse width of the driving pulse of the stepping motor, and 1 pulse timer means the microcontroller MC.
is built in to set the time of one pulse width of the above drive pulse (
(preset) is enabled, and the flow shown in FIG. 12 goes around every gap in the pulse width.

Then, it is determined that one pulse time has elapsed, and if the pulse time has elapsed, the pulse timer is preset, and then it is determined that one feed dog has sunk, and if the feed dog has sunk, the flow shown in Figure 12 is activated. If the feed dog has not sunk, the flow returns immediately. In Fig. 12, the J difference register is a register provided in the microcomputer MC, and its role will be described later, but in the initial state (when the power of the sewing machine is switched from OFF to ON), this register has the RO function. is stored.

Therefore, when 1 difference register ni 0J is determined, first J
It is determined whether the feed origin orientation flag is set or reset.

However, as shown in Fig. 11, the feed origin directional plug cannot be reset unless the sewing machine motor M is stopped by operating the start/stop switch while the sewing machine motor M is rotating. , when the sewing machine motor M stops rotating, the one-step angle detection device SD
It is determined whether J is on or off. (■) Now, a case will be described in which the feed out-of-step correction is performed in a state where the feed origin orientation flag is reset.

If the feed dog sinks and the rotational position of the feed stepping motor SM2 is at L (+23) in Fig. 9, the step angle detection device W is detected.
Since tSD is on, the feed origin orientation flag is set, and immediately after static excitation in state A (a) 001) in Figure 6 is performed for a certain period of time, the stepping motor is driven based on the stitch information from the microcomputer MC. However, although the rotational position is L as shown in x in Figure 19, for example, the step angle detection device is off, so r1 is added to the value stored in the difference register, and the value stored in the difference register becomes 1-. 1J, and a 1-pulse forward rotation routine is applied.

Pulse forward rotation routine - is stepping motor SM2
This is a routine for driving the stepping motor SM2 to the left in FIG. 9 by a step, and after this routine drives the stepping motor SM2 from Becomes ROJ. Next, after the pulse time has elapsed, the value stored in the difference register is ROJ as the feed dog sinks, and since the step angle detection device SD is still off, RlJ is added to the value stored in the difference register, and the value stored in the difference register is ROJ. The stored value becomes RlJ and the one-pulse forward rotation routine is applied again. In this way, each time the stored value of the difference register repeats between RlJ and ROJ, the pulse forward rotation routine operates, and the feed stepping motor SM2 step angle detection device! It continues to be driven to the left in Fig. 9 until SD is turned on, and when the step angle detection device SD is turned on, the feed origin orientation flag is set, and then the static excitation is constant in Fig. 6 A state (A) 001) Since the feed stepping motor SM2 is stopped at L in FIG. 9, the feed step-out correction is completed.

Thereafter, the feed stepping motor is driven based on the stitch information from the microcomputer MC, and its rotational position becomes Y in FIG.
In the above configuration, when the operator senses a step-out while operating the sewing machine with the zigzag pattern selected and operates the start/stop switch, the lower stop flag is set because the sewing machine motor M is still rotating. Ru.

In connection with setting the lower stop flag, the rotation of the sewing machine motor M stops according to the flow shown in Fig. 11 and the needle is stopped at the lower position, and the feed origin orientation flag is reset, but the feed dog sinks in the needle lower position. 12th immediately.
The flow shown in the figure acts to correct the feed out-of-step. next,
When the pattern selection switch 3 is operated to select, for example, buttonhole stitching to form a buttonhole stitch, and the last stitch has been formed, the last needle flag is set, and as described above, it is related to the setting of the last needle flag. and the top stop flag is set.

Then, according to the flow shown in FIG. 11, the upper stop occurs and the feed origin orientation flag is reset, but the flow shown in FIG. 12 does not work in the upper stop because the feed dog has not sunk. When the start/stop switch 4 is operated in order to sew the next buttonhole in this state where the needle is stopped,
The sewing machine motor M is started at a low speed by the motor low speed signal routine. When the needle 5 penetrates the cloth and reaches the lower position, that is, the feed dog is depressed, the feed origin orientation flag remains reset, so the flow shown in FIG. 12 is activated. At this time, while the cloth feed timing signal is generated by the motor low speed signal routine, the stepping motor SM2 is driven at low speed so as to make one round trip, so that sewing can be continued with proper stitches from the first stitch onwards.

In addition, in the above flow, when the top stop occurs in relation to the state in which one-point mode such as buttonhole sewing is selected, the speed at the next startup of the sewing machine is set to a predetermined low speed to compensate for the feed out-of-step. I try to do it, but in other cases,
For example, in a sewing machine that stops at the top in connection with the operation of the thread trimming means, the speed when starting the sewing machine from the top stop may be set to a predetermined low speed to compensate for the feed out-of-step as described above. .

In addition, the above is the flow related to the step-out correction of the feed stepping motor, but for example, the timing to perform the step-out correction is selected at the needle top position, and the step angle detection device is placed at the end of the rotation range of the swing stepping motor. Therefore, it is possible to perform step-out correction of the swing stepping motor using this flow.

As described above, according to the present invention, step-out correction of the stepping motor is performed in conjunction with the operation of the sewing start/stop switch of the sewing machine. The selection pattern is canceled, eliminating the need for complicated operations such as performing the selection operation again, improving work efficiency, and correcting stepping motor step-out each time the start/stop switch is operated. Since the stepping motor can be checked frequently and the stepping motor can always be set in an appropriate state, it is possible to maintain proper stitching.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the sewing machine, Figure 2 is a perspective view of the main parts inside the machine frame of the sewing machine, Figure 3 is a perspective view of the clutch device, Figure 4 is the pulse generator, and Figure 5 is the structure of the stepping motor. Figure 6 is a diagram showing the excitation method of the stepping motor, Figure 7 is a diagram showing one step angle of the stepping motor,
Figure 8 is a diagram showing the rotation range of the swing stepping motor;
Figure 9 is a diagram showing the rotation range of the feed stepping motor;
FIG. 10 is a block diagram of the electric circuit, and FIGS. 11 and 12 are flow charts of the microcomputer. In the figure, M is the sewing machine motor, 13 is the feed dog, SM2
is a feeding stepping motor, MC is a microcomputer, SDR is a drive circuit, 4 is a start/stop switch, 21
23 is a pulse generator, 16 to 20, CMG is a clutch device, and SD is a step angle detection device.

Claims (1)

[Claims] 1. A drive motor connected to the main shaft and capable of being electrically driven or stopped; a cloth feeding means connected to the main shaft so as to give cloth feeding motion to the feed dog; A stepping motor that is connected to the cloth feed means or the needle bar and whose action can set the cloth feed amount of the cloth feed means or the needle swing position of the needle bar; A memory body that stores stitch information corresponding to the needle swing position and cloth feed amount for each stitch of the sewing pattern in advance, and a pattern in which one of the stitch information in the memory body can be selected and read out by manual operation. In a sewing machine having a selection means and a drive circuit that drives a stepping motor based on the read stitch information, a stop signal that enables manual operation and stops the drive motor in connection with an operation while the drive motor is being driven is provided. operating means 4 for generating an activation signal which causes the drive motor to be in a driving state in connection with an operation of the drive motor during a standstill; a detection means (SD) that generates a detection signal, a correction means that can command a drive circuit to drive the stepping motor in a specific step angle direction and statically excite for a certain period of time in relation to the generation of the detection signal, and a stop signal. or a control means for operating the correction means in relation to the generation of the start signal.