JP5160834B2 - Control device for carriage driving motor of flat knitting machine - Google Patents

Description

  The present invention relates to a controller for a motor for driving a carriage of a flat knitting machine for driving a carriage that causes a knitting needle to perform a knitting operation while traveling along a needle bed.

  Conventionally, for example, as introduced as a general flat knitting machine in the column of the prior art of Patent Document 1, a carriage having a knitting cam for knitting is provided on a needle bed in which knitting needles are arranged. It can be reciprocated along it. A servo motor is used as the carriage driving motor of such a flat knitting machine, which is called a main motor and serves as a driving force for the knitting operation.

  In a flat knitting machine, the rating of the carriage drive motor is selected so as to have a sufficient output for a knitting pattern that involves the use of a knitting needle that maximizes the load. Generally, a motor has a continuous rating that can be used continuously and an intermittent rating that can be used for a short time. When the motor is electrically driven, an electric loss and a mechanical loss are generated to generate heat. The carriage driving motor is selected so that the maximum load is, for example, about 80% of the continuous rating. Whatever knitting width or pattern knitted fabric can be knitted by a flat knitting machine user, the heat generated by the motor may exceed the heat-resistant temperature of electrical insulators and the life of the motor may be shortened. This is to prevent it from occurring.

  A needle selection mechanism is mounted on the carriage together with the knitting cam. The knitting needles arranged in the needle bed are acted upon by the knitting cam when selected by the needle selection mechanism when passing through the carriage. The selection of the knitting needle is performed according to the knitting width and knitting pattern of the knitted fabric. In normal knitted fabric knitting, the load factor of the carriage drive motor reaches only about 50 to 70% of the rating when the rating is selected as described above. The knitting at maximum load is infrequent. A motor with a large rating is larger and more expensive than a motor with a lower rating. Selection of a carriage drive motor under conditions that provide sufficient output even at the maximum load results in selection of a large and expensive motor because of rare conditions.

In a honing machine in the field of machine tools, for example, Patent Document 2 discloses a prior art for monitoring a load of a servo motor when the servo motor is used for driving a grindstone expansion device. In the honing machine, the grindstone is shrunk to be inserted into the machining hole with a reduced outer diameter, and then the servomotor is rotated at a high speed until it contacts the inner wall of the machining hole to rapidly expand the grindstone. If the grindstone comes into contact with the machining hole too rapidly, a large load or impact is applied to the grindstone, which may cause the wheel to be broken or the machinability to be lowered. In this prior art, the contact of the grindstone with the inner wall is detected by a sudden increase in load, and the rotation of the servo motor is switched to a low speed so that the grindstone is expanded at a low speed by cutting feed. Therefore, the monitoring of the load of the servo motor in this prior art is not performed for the purpose of protecting the grinding wheel driven by the servo motor, but for the purpose of protecting the servo motor itself.
JP-A-6-280141 JP 60-217059 A

  The object of the present invention is to prevent the shortening of life due to heat generation without lowering the knitting efficiency at the time of knitting at the maximum load, etc., even if an inexpensive motor rated for the load that is normally used is selected. To provide a control device for a carriage driving motor of a flat knitting machine.

The present invention relates to a controller for a carriage drive motor of a flat knitting machine that reciprocates along a needle bed.
An output circuit capable of applying output power to the carriage drive motor;
A monitoring circuit for monitoring the load factor of the carriage drive motor;
Even if the carriage drive motor is driven continuously, the difference between the load factor monitored by the monitoring circuit and the safe load factor that has a certain margin until the temperature rise reaches the allowable limit value is preliminarily determined based on the measured data. A temperature estimation circuit that correlates the set temperature change rate and estimates the temperature of the carriage drive motor from the temperature change rate;
If the estimated temperature of the carriage drive motor by the temperature estimation circuit exceeds the allowable limit value, the output power applied from the output circuit to the carriage drive motor is reduced, and the estimated temperature cannot exceed the allowable limit value while the output power is being reduced. And a protection circuit that controls the output circuit to protect the carriage drive motor so as to stop the reduction and return the output power ,
Reduction of the output power applied to the carriage drive motor by the output circuit is carried out in the next course running after the carriage running in which the estimated temperature exceeds the allowable limit value . It is a control apparatus of a drive motor.

In the present invention, the output power applied from the output circuit to the carriage driving motor is reduced so as to reduce the maximum traveling speed of the carriage.

In the present invention, the output power applied from the output circuit to the carriage driving motor is reduced so as to reduce the acceleration of the carriage.
In the present invention, the output power applied from the output circuit to the carriage driving motor is reduced so as to reduce the maximum traveling speed of the carriage and reduce the acceleration of the carriage.

  In the present invention, the monitoring circuit monitors an average load factor within a predetermined time as the load factor.

  In the present invention, the protection circuit may gradually reduce the output power or return the output power by controlling the output circuit in a plurality of stages.

  In the present invention, the protection circuit may change the degree to which the output power applied from the output circuit to the carriage driving motor is reduced according to the load factor monitored by the monitoring circuit. To do.

  Further, in the present invention, the temperature estimation circuit divides a difference between the safe load factor and the load factor monitored by the monitoring circuit into a plurality of ranges so that the temperature change rate corresponds to each range. The temperature change rate is made to correspond with reference to the set table data.

  According to the present invention, a control device for a carriage driving motor of a flat knitting machine that reciprocates along a needle bed includes an output circuit, a monitoring circuit, a temperature estimation circuit, and a protection circuit. The output circuit can apply output power to the carriage driving motor. The monitoring circuit monitors the load on the carriage driving motor. The temperature estimation circuit associates the difference between the safe load factor of the carriage drive motor and the load factor monitored by the monitoring circuit with a temperature change rate set in advance based on the actual measurement data, and calculates the carriage drive motor from the temperature change rate. Estimate the temperature. In the safe load factor, even if the carriage driving motor is driven continuously, there is a certain margin until the temperature rise reaches the allowable limit value. The protection circuit reduces the output power applied to the carriage drive motor from the output circuit when the estimated temperature of the carriage drive motor by the temperature estimation circuit exceeds the allowable limit value, and the estimated temperature falls within the allowable limit while the output power is being reduced. If the value does not exceed the value, the reduction is stopped and the output power is returned to control the output circuit to protect the carriage driving motor. The carriage drive motor reduces the rotational speed by reducing the applied output power, and the carriage travel speed decreases to reduce the load, thus protecting the carriage drive motor from heat generation due to excessive load. Can do. The protection circuit controls the output circuit so that the output power is returned when the estimated temperature does not exceed the allowable limit value while the output of the carriage drive motor is being reduced. The rotational speed can be recovered and the carriage traveling speed can be returned to avoid a decrease in productivity. As the carriage driving motor, an inexpensive motor rated for the load that is normally used can be selected and used efficiently. When knitting at the maximum load, etc., the load factor is monitored and continuous use at a load larger than the rating is allowed at the beginning to improve production efficiency.If the estimated temperature exceeds the allowable limit value, the output current is It is possible to prevent the shortening of life due to heat generation.

Further , the output power applied to the carriage driving motor by the output circuit is reduced during the next course after the carriage traveling in which the estimated temperature exceeds the allowable limit value is completed. In the course during the knitting operation, the condition for driving the carriage is not changed, so that it is possible to avoid the appearance of the knitted fabric from being deteriorated by changing the loop length of the stitch to be knitted in the course.

  Further, according to the present invention, the output power applied from the output circuit to the carriage driving motor is reduced so as to reduce the maximum traveling speed of the carriage. By reducing the maximum traveling speed of the carriage, the load required for driving for knitting needle selection and knitting operation and the load due to sliding friction associated with traveling are reduced.

  Further, according to the present invention, the output power applied from the output circuit to the carriage driving motor is reduced so as to reduce the acceleration of the carriage. When the traveling direction is reversed outside the range of the knitting width, it is necessary to accelerate the carriage from the stopped state to the maximum traveling speed, but the load can be reduced by reducing the acceleration.

  Further, according to the present invention, the monitoring circuit monitors the average load factor within a predetermined time as the load factor. Therefore, the monitoring circuit reflects the use state of the motor that needs protection, not the instantaneous load fluctuation for each knitting needle. The rate can be monitored.

  Further, according to the present invention, the protective circuit gradually reduces the output power by controlling the output circuit or returns the output power in a plurality of stages, so that abrupt fluctuations in the traveling state of the carriage are avoided, The influence on the knitting state of the knitted fabric can also be reduced.

  Further, according to the present invention, the protection circuit changes the degree to which the output power applied from the output circuit to the carriage driving motor is reduced according to the magnitude of the load factor monitored by the monitoring circuit. Accordingly, the output power can be reduced.

  Further, according to the present invention, the temperature estimation circuit corresponds the temperature change rate with reference to the table data based on the actual measurement data to the difference between the safe load factor and the load factor monitored by the monitoring circuit. Even a temperature close to the value can be estimated with high accuracy.

  In the following, an optimum embodiment for carrying out the present invention will be shown.

  FIG. 1 shows a schematic external configuration of a flat knitting machine 1 according to an embodiment of the present invention. The flat knitting machine 1 includes a needle bed 2 at the front and rear, and is opposed to each other by an intermediate tooth opening 3. The front and rear needle beds 2 are each provided with a carriage 4, and the front and rear carriages 4 are connected by a bridge 5 at the portion of the tooth opening 3. The carriage 4 is driven to reciprocate in the longitudinal direction of the needle bed 2 that is the left-right direction in the drawing. A plurality of yarn path rails 6 are installed above the tooth opening 3. Although not shown in the drawings, a yarn feeder as a yarn supplying member that supplies knitting yarn to the tooth mouth 3 is supported on the yarn path rail 6 so as to be able to run. The bridge 5 is provided so as to straddle the yarn path rail 6, and one yarn feeder can be selected from a plurality and can be taken along. When performing splicing and the like, a plurality of yarn feeders may be taken to a set of needle selection mechanisms and cam mechanisms. Each yarn feeder is supplied with a knitting yarn from the knitting yarn cone 7 via a yarn feeding mechanism such as a top spring device 8.

  A large number of knitting needles are arranged in the needle bed 2, and a knitting operation is selectively performed by a needle selection mechanism and a cam mechanism mounted on the carriage 4. In the knitting operation, the hook at the tip of the knitting needle is advanced to the tooth opening 3 and the knitting yarn supplied from the yarn feeder is repeatedly drawn into the needle bed 2. One or a plurality of system needle selection mechanisms and cam mechanisms are mounted on the carriage 4. When a cam mechanism of a plurality of systems is mounted on the carriage 4, the plurality of yarn feeders can be taken along and the knitted fabrics of the plurality of courses can be knitted by one run of the carriage 4. The knitting of the knitted fabric is performed according to control by the controller 9 to which knitting data created in advance is input.

  The reciprocating travel of the carriage 4 is driven by a main motor 10 as a carriage driving motor. For example, a driving belt 11 installed along the needle bed 2 is joined to the carriage 4, and the rotational force of the main motor 10 is converted into a linear driving force via a transmission mechanism 12 including a timing belt. By switching the rotation direction of the main motor 10, the traveling direction of the carriage 4 is switched.

  A servo motor is used as the main motor 10. The controller 9 includes a servo amplifier 13, a torque monitor 14, a protection circuit 15, and a temperature estimation circuit 16. The servo amplifier 13 functions as an output circuit for supplying output power to the main motor 10. The torque monitor 14 detects the output torque of the main motor 10 proportional to the output current of the servo amplifier 13 as a load, and functions as a monitoring circuit.

  FIG. 2 shows an example of control used while protecting the main motor 10 by the controller 9 of the flat knitting machine 1 shown in FIG. This control is executed every processing cycle of the controller 9. If the average load torque calculation executed in step s1 is performed over a predetermined time, the processing cycle is longer than the predetermined time. The predetermined time can be about 30 seconds, for example. Within this predetermined time, the carriage 4 travels a plurality of times.

  In each processing cycle, first, in step s1, the torque monitor 14 monitors the torque for a predetermined time. Next, in step s2, the temperature estimation circuit 16 estimates the motor temperature from the average load torque that is the monitoring result of the torque monitor 14. The estimation of the motor temperature is performed by simulating the motor temperature and the allowable maximum temperature rise value at the maximum outside temperature allowed by the flat knitting machine 1 based on the load torque versus temperature change data. For example, even if the main motor 10 is continuously used, a safe load factor (a%, 0 ° C.) with a margin of 5 ° C. up to the allowable maximum temperature rise value is used as a reference. While monitoring the current load factor (n%) with a period of every 30 seconds as 1 count, temperature rise or fall is simulated based on table data as shown in Table 1 below.

  For example, if the flat knitting machine 1 has been stopped for a sufficiently long time, the motor temperature should match the outside air temperature, and the calculation is performed so as to integrate the temperature change for each count after starting the main motor 10. Then, the motor temperature can be estimated. Although the estimated motor temperature is not an actual measurement value but a virtual one, it is based on prior actual measurement data and is expected to have high accuracy.

  In step s3, the protection circuit 15 compares the virtual temperature estimated by the temperature estimation circuit 16 with an allowable temperature based on an allowable limit value such as an allowable maximum temperature rise value. When it is determined in step s3 that the virtual temperature exceeds the allowable temperature, in step s4, the speed reduction coefficient having an initial value of 1.0 is multiplied by a reduction ratio of 0.9, for example, to obtain a speed reduction coefficient. Is set to 0.9, the speed is limited, and the display indicating that the speed is being reduced is displayed in step s5. The display during the speed reduction is performed by, for example, a display provided on the operation panel of the controller 9 of the flat knitting machine 1, or by blinking a display lamp provided on the upper part of the flat knitting machine 1.

  The reduction rate can be set in increments of 0.1 within a range of 0.1 to 1.0, for example. The motor also has an intermittent rating that can withstand a short time, such as 200 seconds at 150%, even if it exceeds 100% of the continuous rating. Therefore, even if a load torque exceeding the safe load ratio is applied, the life of the motor is not shortened for a short time within the intermittent rating, and the carriage 4 can be driven with an output commensurate with an instantaneously increasing load.

  If it is determined in step s3 that the virtual temperature does not exceed the allowable temperature, the speed reduction coefficient is set to an initial value of 1.0 in step s6. The speed reduction coefficient is set to 1.0 when the virtual temperature is determined not to exceed the allowable temperature at all in step s3, and after the virtual temperature exceeds the allowable temperature and the knitting speed is reduced. In some cases, the virtual temperature may be recovered so as not to exceed the allowable temperature by reducing the load. When the virtual temperature has recovered, setting the speed reduction coefficient to 1.0 means returning the speed reduction coefficient that has been reduced by multiplying the reduction ratio in step s4 to the initial value.

  The allowable temperature serving as a reference for releasing the speed limit may be different from the allowable temperature serving as a reference for the speed limit. As described above, the speed limit is performed at a temperature increased by 5 ° C. based on a temperature having a margin of 5 ° C. up to the allowable temperature increase value, that is, the allowable temperature increase value. If the speed limit is canceled at 0 ° C. from the reference temperature, the speed limit is canceled at a temperature that is 5 ° C. lower than the allowable temperature increase value, and the motor can be reliably protected.

  After step s5 or step s6 is completed, the knitting speed at which the carriage 4 runs in step s7 is calculated by multiplying the command speed commanded by the controller 9 by the speed reduction coefficient and reflected for each course. That is, if the carriage 4 is traveling at the time of calculating the average load torque in step s1, the reflection to the knitting speed calculated in step s7 is that the traveling course ends and the next course travels. Become. In the course during the knitting operation, the condition for driving the carriage is not changed, so that the stitch loop length to be knitted can be prevented from changing in the course.

  In addition, although the speed limit in step s4 and the speed return in step s6 are performed in one process, they can be changed gradually in a plurality of times. Since the reduction of the output power or the return of the output power is gradually performed in a plurality of stages, the influence on the knitting state of the knitted fabric can be reduced by avoiding a sudden change in the traveling state of the carriage 4. Whether the change is performed once or divided into a plurality of times can be determined according to the degree to which the average load torque calculated by the torque monitor 14 exceeds the safe load factor. Since the degree of reduction of the output power applied from the servo amplifier 13 to the main motor 10 is changed according to the magnitude of the load monitored by the torque monitor 14, the output power can be reduced according to the necessity of protection. it can.

  Furthermore, since the load of the main motor 10 is monitored by the output torque detected by the torque monitor 14 and the motor temperature is virtually calculated, for example, it is not necessary to detect the surface temperature of the main motor 10, and the temperature sensor Can be implemented at low cost. Further, since the controller 9 controls the knitting operation of the main motor 10 and the knitting needle according to the knitting data, it is possible to calculate the load according to the control state and obtain the average load torque only by calculation.

  As described above, the protection circuit 15 of the controller 9 calculates the virtual motor temperature by monitoring the load factor of the main motor 10 that is a carriage driving motor, and the motor load factor increases depending on the knitting pattern. When the temperature exceeds the allowable temperature, the output of the main motor 10 for running the carriage 4 in the next course knitting is lowered, so that the main motor 10 can be prevented from generating heat and shortening its life. As the main motor 10, an inexpensive motor rated for the output that is normally used is selected, but when performing knitting at the maximum load, it is protected so that the load is reduced after using the maximum load as much as possible. Shortening due to heat generation can be avoided without reducing the knitting efficiency.

  FIGS. 3A and 3B show changes in travel speed before and after changing the carriage travel speed when the reduction rate in step s4 of FIG. 2 is 0.9 in FIGS. Show. When reversing the direction in reciprocating travel, the carriage 4 is temporarily stopped and then accelerated, and maintained at the maximum travel speed and then decelerated. Before the change shown in (a), the maximum running speed is the maximum knitting speed V, whereas in the speed change shown in (b), the maximum running speed is reduced to 0.9V. The load applied while the carriage 4 is traveling at the maximum traveling speed can be reduced by reducing the traveling speed.

  Note that the load on the main motor 10 which is a carriage driving motor can be reduced by changing the acceleration as shown in FIG. That is, before the change, as shown in (a), the vehicle is accelerated so as to reach the maximum knitting speed V from time t1 at time t1, but as shown in (c), the acceleration is reduced and time t1 is reached. If the maximum knitting speed V is reached in a longer time t2, the load during acceleration can be reduced. Furthermore, as shown in (d), both the speed and the acceleration can be changed, and the maximum traveling speed reached at time t3 longer than time t1 can be reduced to 0.9V.

  4, 5, and 6 show a comparison between the case of no speed limit control, the case of speed limit according to the load factor, and the case of speed limit based on virtual temperature calculation in this embodiment.

  When the speed limitation as shown in FIG. 4 is not performed, if the load factor is kept at 95% from time t0 to time t2 as shown in (a), the temperature of the motor at time t1 as shown in (b). The allowable temperature is exceeded. Since it is used in a state where the temperature exceeds the allowable temperature from the time t1 to the time t2, the life of the main motor 10 is shortened.

  As shown in FIG. 5A, when the load factor is monitored, if the load factor exceeds the reference, the speed reduction coefficient is multiplied, and if the load factor falls below, the temperature exceeds the allowable temperature as shown in FIG. 5B. There is nothing. For example, when the main motor 10 is driven from time t10 to time t12, the speed is reduced if the load factor exceeds the reference at time t11. However, since the speed limit is performed in a state where there is a margin up to the allowable temperature, the knitting efficiency is deteriorated.

  As shown in FIG. 6A, the virtual motor temperature calculated based on the actually measured load factor and temperature rise table is monitored. If the virtual motor temperature exceeds the allowable temperature, the speed is decreased, and if the virtual motor temperature falls below, the speed is decreased. Try to return the speed. For example, the motor temperature exceeds the allowable temperature between time t20 and time t27, between time t21 and time t22, between time t25 and time t26, and the like. Even if the motor temperature instantaneously exceeds the permissible temperature, the motor temperature decreases due to speed limitation at time t22 or time t26, and the knitting efficiency can be increased without shortening the life of the main motor 10.

1 is a front view illustrating a schematic external configuration of a flat knitting machine 1 including a carriage driving motor control device according to an embodiment of the present invention. 3 is a flowchart illustrating an example of control that is used while protecting the carriage driving motor by the controller 9 of the flat knitting machine 1 shown in FIG. 1. Change the travel speed of the carriage drive motor before the change for protection and change the maximum speed to reduce the travel speed change and acceleration when changing the protection of the carriage drive motor. 5 is a time chart showing a change in travel speed when protecting the carriage drive motor and a change in travel speed when protecting the carriage drive motor by changing the maximum speed and the acceleration to reduce the acceleration. It is a time chart which shows the relationship between the change of a load factor, and a temperature rise about the case without speed limit control. It is a time chart which shows the relationship between the change of a load factor, and a temperature rise about the case of the speed limit according to a load factor. It is a time chart which shows the relationship between the change of a load factor, and a temperature rise about the case of speed restriction | limiting based on virtual temperature calculation in a present Example of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat knitting machine 2 Needle bed 3 Tooth mouth 4 Carriage 9 Controller 10 Main motor 13 Servo amplifier 14 Torque monitor 15 Protection circuit 16 Temperature estimation circuit

Claims (8)

In the controller for the carriage drive motor of the flat knitting machine that reciprocates along the needle bed,
An output circuit capable of applying output power to the carriage drive motor;
A monitoring circuit for monitoring the load factor of the carriage drive motor;
Even if the carriage drive motor is driven continuously, the difference between the load factor monitored by the monitoring circuit and the safe load factor that has a certain margin until the temperature rise reaches the allowable limit value is preliminarily determined based on the measured data. A temperature estimation circuit that correlates the set temperature change rate and estimates the temperature of the carriage drive motor from the temperature change rate;
If the estimated temperature of the carriage drive motor by the temperature estimation circuit exceeds the allowable limit value, the output power applied from the output circuit to the carriage drive motor is reduced, and the estimated temperature cannot exceed the allowable limit value while the output power is being reduced. And a protection circuit that controls the output circuit to protect the carriage drive motor so as to stop the reduction and return the output power,
Reduction of the output power applied to the carriage drive motor by the output circuit is carried out in the next course running after the carriage running in which the estimated temperature exceeds the allowable limit value. Drive motor control device.   2. A control device for a carriage driving motor of a flat knitting machine according to claim 1, wherein the output power applied from the output circuit to the carriage driving motor is reduced so as to reduce the maximum traveling speed of the carriage. . The reduction of the output circuit output power applied to the carriage drive motor, the flat knitting machine of the carriage drive motor control apparatus according to claim 1, characterized in that to reduce the acceleration of the carriage. The flat knitting machine according to claim 1, wherein the output power applied from the output circuit to the carriage driving motor is reduced so as to reduce the maximum traveling speed of the carriage and reduce the acceleration of the carriage. Control device for the carriage drive motor.   2. The controller for a carriage driving motor of a flat knitting machine according to claim 1, wherein the monitoring circuit monitors an average load factor within a predetermined time as the load factor.   The carriage circuit of the flat knitting machine according to claim 1, wherein the protection circuit gradually reduces the output power by controlling the output circuit or returns the output power in a plurality of stages. Motor control device.   2. The protection circuit according to claim 1, wherein the degree of reduction of output power applied from the output circuit to the carriage driving motor is changed according to a load factor monitored by the monitoring circuit. Control device for carriage drive motor of flat knitting machine.   The temperature estimation circuit divides the difference between the safety load factor and the load factor monitored by the monitoring circuit into a plurality of ranges, and the temperature change rate is set to correspond to each range. The control device for the motor for driving the carriage of the flat knitting machine according to any one of claims 1 to 7, wherein the temperature change rate is associated with reference to the data.

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