JPH0632741B2 - Sewing machine controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called belt drive type sewing machine control device for connecting a motor and a sewing machine with a belt and transmitting the rotational force of the motor to the sewing machine. is there.

2. Description of the Related Art The conventional belt drive type sewing machine drive system described above will be described below with reference to FIG.

In FIG. 7, reference numeral 1 denotes a sewing machine, which is connected to a motor 2 via a sewing machine pulley 3, a belt 4, and a motor pulley 5. 6 is a control device, 7 is a pedal, and 8 is a needle position detector for detecting the needle position.

The operation of the sewing machine drive system configured as above will be described below.

First, when the pedal 7 is depressed, the control device 6 detects the depressed position of the pedal 7 by a built-in pedal sensor circuit, starts the motor 2 when the pedal 7 reaches a certain depressed position, and further moves to the depressed position. According to the speed setting, the speed is controlled so that the deviation from the actual speed from the speed detector built in the motor 2 becomes small.

The rotational force of the motor 2 is transmitted to the sewing machine 1 via the motor pulley 5, the belt 4 and the sewing machine pulley 3, the sewing machine is activated, and the sewing machine 1 is operated at a speed according to the depressed position of the pedal 7.

Next, the pedal 7 is moved to its original position (hereinafter referred to as the neutral position).
Then, the controller 6 stops the sewing machine 1 at the predetermined needle position (needle up position or needle down position) detected by the needle position detector 8.

Problems to be Solved by the Invention As described above, the conventional one controls the speed of the motor 2 in accordance with the operation of the pedal 7, and as a result, the ratio of the sizes of the sewing machine pulley 3 and the motor pulley 5 is naturally increased. Therefore, the speed of the sewing machine 1 changes even if the speed setting by the pedal 7 is constant. Therefore, usually, the desired sewing machine speed may not be obtained due to the work of selecting and determining the motor pulley diameter from the desired sewing machine speed after measuring the sewing machine pulley diameter, or due to the difficulty in obtaining the determined motor pulley. Had problems such as.

In view of the above problems, the present invention provides a sewing machine control device in which the relationship between the pedal depression position and the sewing machine speed is constant regardless of the ratio between the motor pulley and the sewing machine pulley.

Means for Solving the Problems In order to solve the above problems, a sewing machine control device of the present invention includes a counter for counting speed detection signals from the speed detector between generation signals of the needle position signal, and the pedal. A multiplier that multiplies a speed command signal corresponding to the stepped position of the pedal with a settable multiplier value and outputs a speed setting value; speed control means for controlling the speed to a speed according to the speed setting value; computing means; prohibiting means It has the configuration.

Action According to the present invention, with the above-mentioned configuration, the calculating means calculates the pulley ratio between the sewing machine pulley diameter and the motor pulley diameter based on the count result of the counter, and further sets the pulley ratio in the multiplier as the multiplier value. As a result, the speed command signal comes to command the sewing machine speed, and the speed control means controls the motor speed according to the speed set value. On the other hand, it has the function of automatically keeping the sewing machine speed constant. When the count result value is larger than the specified value or smaller than the specified value, the calculation by the calculation means is prohibited to prevent the influence of external noise or the like.

Embodiment A sewing machine control device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a block diagram of a sewing machine controller as one embodiment of the present invention. In FIG. 1, reference numeral 9 denotes a speed setter, which detects the amount of pedal depression and outputs the sewing machine start command signal S _D and the sewing machine speed command signal P _S as digital values. 10 is a multiplier, 11 is a speed control circuit, 12 is a motor, 13 is a speed detector that detects the speed of the shaft of the motor 12 and outputs a pulsed speed detection signal P _E , and 14 is the motor 12 and the belt. A sewing machine connected via the sewing machine 14, 15 is a needle position detector which is connected to the shaft of the sewing machine 14 and detects a needle position (needle up position or needle down position) and outputs a needle position signal N _D , 16 is a counter, 17 Is a latch circuit including a D flip-flop, and 18 is an arithmetic circuit.

Further, FIG. 2 shows a concrete configuration example of the arithmetic circuit 18. In FIG. 2, 19 is a central processing unit (hereinafter referred to as cp
u) and is synchronized with the clock signal from the oscillation circuit 20. The input from the input port 21 and the output port 22
From the RAM, input / output to / from the RAM 23, and reading of instructions from the RoM 24. Reference numeral 25 denotes a reset circuit, which automatically switches from "L" to "H" after the operating voltage for operating the above circuits is stabilized after the power is turned on, and from this point the processing of the cpu19 is performed. Is about to start.

The operation of the sewing machine controller configured as described above will be described below with reference to FIGS. 3 and 4, particularly in the portion of FIG.

First, in FIG. 1, when the pedal is depressed for a certain amount or more, a start command signal S _D is output from the speed setter 9, the speed control circuit 11 starts the motor 12, and therefore the sewing machine 14 connected by the belt is also simultaneously started. to start. On the other hand, the speed setter 9 outputs a speed command signal P _S according to the pedal depression position, and the multiplier 10 multiplies the set value D _P from the arithmetic circuit 18 to set the speed set value P _M to the speed control. The speed control circuit 11 applies a feedback control operation to the circuit 11 so that the speed detection signal P _E from the speed detector 13 for detecting the speed of the motor 12 becomes equal to the speed set value P _M. The motor 12 uses the speed setting value P
_The speed is controlled so that the rotation speed is instructed by _M.

Next, when the pedal is returned to the neutral position, the speed setter 9 turns off the start command signal S _D , and the speed control circuit 11 first sets a sufficiently low speed for positioning the needle according to the speed command signal P _S. Then, the speed detection signal P _E is measured, and when the actual speed reaches the positioning speed and the needle position signal N _D is output, the motor 12 is stopped and the sewing machine 14 is moved to a predetermined needle position. Stop.

As described above, the variable speed operation by depressing the pedal and the fixed position stop control of the needle by the pedal neutrality are repeated to perform the sewing. Here, the set value D _P , which is the gist of the present invention, will be described below. Describe.

The counter 16 operates so as to count the speed detection signal P _E after the needle position signal N _D is reset at the rear edge when switching from “H” to “L”, and the latch circuit 17 is operated.
Represents the output data D _C of the counter 16 as described above,
When the needle position signal N _D is switched from “H” to “L”, it is latched and output to the arithmetic circuit 18.

In FIG. 2, first, when the power is turned on and the reset signal from the reset circuit 25 switches from “L” to “H”, the cpu 19 starts its operation and fetches the instruction word from the RoM 24 to execute it. Start.

In FIG. 3, the set value D _P1 is first set in the initial state immediately after the reset signal is switched from “L” to “H”. Next, the pedal is depressed and the start command signal S _D
Interrupt is permitted from the time when the "L" → "H" is switched, and at the second switching point "H" → "L" of the needle position signal N _D , that is, the sewing machine 14 makes one revolution. Data D _{E of} the latch circuit 17, that is,
The number of pulses of the speed detection signal P _E indicating the rotation angle of the motor 12 during one rotation of the sewing machine 14 is input, and the calculation is performed by substituting it into the following equation (1).

D _P = D _E ÷ R (1) (where R is the number of pulses of the speed detection signal P _E for one rotation of the motor) That is, the result D _P in equation (1) is the rotation angle ratio of the motor shaft to the sewing machine shaft, , The ratio of the sewing machine pulley diameter to the motor pulley diameter (hereinafter referred to as the pulley ratio). Therefore, if the speed command value of the sewing machine is N _SM and the speed command value of the motor is N _MT , the expression (2) is established.

N _MT = N _SM × D _P (2) The motor speed command value N _MT in the equation (2) corresponds to the speed set value P _M in FIG. 2, and therefore the speed command signal P _S is the sewing machine speed command. It can be said that it shows the value. Therefore, it can be said that the above shows a correction means for obtaining a constant sewing machine speed for any pulley ratio.

Here, the aforementioned pulley ratio D _P1 at the time of initial setting
Since not be measured immediately after power-on, but a suitable value is set, the low speed when positioning the needle as described above is (given as a speed setting signal P _S even when the pedal neutral), too high In this case, there is a problem that the slip angle of the needle stop position becomes large and the stopping accuracy deteriorates.Therefore, a small value among the usually considered pulley ratios, for example, a value such as 1/3 to 1/4. Is selected.

Further, the part shown by the broken line in FIG. 3 (b) shows the processing in the case of an abnormality. That is, 26 indicates that when the pseudo needle position signal N _D is continuously input from “H” to “L” due to noise or the like, the latch output D _E becomes a very small value. Further, reference numeral 27 indicates a prohibition means for not performing calculation, and not performing calculation when the latch output D _E becomes a very large value due to noise added to the speed detection signal P _E.

FIG. 4 details the method of setting the set value D _P until the calculation of the pulley ratio is completed, and will be described below with reference to FIG. Normally, a timer built in the cpu 19 performs an interrupt process at regular intervals t1. In FIG. 3, when the start command signal S _D is output, the timer process becomes effective, and the timer interrupt process is performed along with the interrupt process (“H” → “L”) by the pulse signal of the speed detection signal P _E. wherein the period of the speed detection signal P _E is measured, the period t ₁ × when it exceeds T _M1 repeating the slight value △ D _P control such as to apply to said pulley ratio D _P successively by. That is, the control of the motor 12 generally has the characteristic that the speed decreases as the load torque increases, and it is possible that the motor cannot be started if the speed is set too low. Means for increasing the value D _P are effective.
It should be noted that the above-mentioned T _M1 may be set to a value corresponding to a speed low enough to determine whether or not the motor 12 has started.

Examples of the time charts for the above-described operations of FIGS. 3 and 4 are shown in FIGS. 5 and 6, respectively, and further description will be given according to the same drawings.

As shown in FIG. 5, until the needle position signal N _{D, which} is generated once for each revolution of the sewing machine 14, passes twice, the set value D _P is set to a sufficiently small value D _P1 and the motor speed is Starts operating at a low speed, but after calculating the pulley ratio as described above, the speed is switched to the normal speed setting, and the motor speed based on the calculation result value D _P2 is obtained thereafter.

Next, as shown in FIG. 6, activated when instruction signal S _D is as the motor 12 is large perforations load immediately after being outputted can not be started, △ D _P one by the set every time t1 Raise the value, start at ts, and then operate as described above.

As described above, by providing the arithmetic circuit 18 and the multiplier 10 according to the present invention, actually measuring the ratio of the machine pulley diameter and pulley diameter, the actual to the speed command signal P _S by the multiplier 10 Since the speed setting value P _M of the motor 12 is output by multiplying the pulley ratio, the speed command signal P _S commands the sewing machine speed.
That is, in other words, according to the present invention, since the sewing machine pulley diameter and the motor pulley diameter are actually measured and automatically corrected,
The sewing machine speed as set can be obtained with any pulley ratio.

Further, according to the present invention, the operation for inhibiting the pseudo signal due to the external noise of the needle position signal N _D or the speed detection signal P _E by the prohibition means as shown by the broken line in FIG. Therefore, a highly reliable sewing machine controller is constructed.

The above-mentioned needle position signal N _D is generated once for each rotation, but it goes without saying that the object of the present invention can be achieved even if a plurality of needle position signals N _D are arranged at one rotation. Becomes That is, if the number of the detection signals is M, it can be said that the following equation (3) may be used as an arithmetic expression. (Instead of expression (1)) Effects of the Invention As described above, the present invention is a counter that counts speed detection signals between generation signals of a needle position signal and outputs a count result value,
A multiplier that multiplies the speed command signal by a settable multiplier value and outputs the speed setting value, calculation means that performs calculation when the counting is completed, and sets the calculation result to the multiplier value. By providing a prohibition means for prohibiting the calculation by the calculation means when it is larger or smaller than the specified value, the ratio of the sewing machine pulley diameter to the motor pulley diameter is actually measured, and it acts so as to automatically correct it. The sewing machine speed can be obtained as set even for the ratio. In addition, the sewing machine control device having an extremely high reliability can be obtained, which acts to prohibit the operation of the pseudo signal due to external noise or the like.

[Brief description of drawings]

FIG. 1 is a block diagram of a sewing machine controller according to an embodiment of the present invention, FIG. 2 is a block diagram of an arithmetic circuit in the same, FIGS. 3 and 4 are flowcharts showing arithmetic operation, FIG. FIG. 6 is a time chart showing the operation,
FIG. 7 is a front view of a sewing machine showing a configuration of a conventional example. 9 ... Speed setter, 10 ... Multiplier, 11 ... Speed control circuit, 12 ... Motor, 13 ... Speed detector, 14 ...
Sewing machine, 15 ... Needle position detector, 16 ... Counter, 1
8 ... Arithmetic circuit.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Doi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP 58-111155 (JP, A) JP 55-92585 (JP, A) JP 61-257686 (JP, A) JP 61-257689 (JP, A) JP 61-52174 (JP, A) JP 61-257690 (JP, A) Kaisho 61-257688 (JP, A)

Claims (1)

[Claims] 1. A speed setter for generating a speed command signal, a motor, speed detecting means for generating R speed detection signals per rotation to detect the speed of the motor, a speed set value and the speed. Speed control means for controlling the speed of the motor by a detection signal, a needle position detector that detects the needle position of the sewing machine and generates a needle position signal, and the speed detection signal between the generation signal of the needle position signal. A counter that counts and outputs a count result value C, a multiplier that multiplies the speed command signal by a settable multiplier value and outputs the speed set value, and performs a calculation C / R when the counting ends. A calculation means for setting the calculation result to the multiplier value, and a prohibition means for prohibiting the calculation by the calculation means when the count result value C is larger than a prescribed value X or smaller than a prescribed value Y. Sewing machine controller