JP2011256468A - Flat-knitting machine and power-saving control method of flat-knitting machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of times to use a servomotor as a servobrake for racking needle beds while preventing inadvertent movement of the needle beds, thereby saving power.SOLUTION: In a flat-knitting machine having a pair of front-and-rear needle beds, one of which is rackable to the other by means of a servomotor, a brake is provided for inhibiting racking of the needle beds. Based on knitting data of the knitted fabric, a slide force imparted from the fabric or carriage to the needle beds is determined. When the determined slide force is under a first predetermined value and the needle beds are not racked by means of the servomotor, the excitation of the servomotor is released and the brake is switched on.

Description

  The present invention relates to a flat knitting machine, and more particularly to control of needle bed racking.

  The flat knitting machine includes a pair of front and back needle beds, for example, one of which is rackable with respect to the other needle bed. By allowing the needle beds to be racked together, the range in which the stitches can be moved is widened, and various knitted fabrics can be knitted. Here, the racking of the needle bed is controlled by a servo motor, and when the needle bed is not racked, the servo motor is used as a servo brake. However, in order to use it as a servo brake, it is necessary to excite the coil of the servo motor, which requires electric power. On the other hand, most of the knitting course (carriage stroke) of the knitted fabric, for example, about 80% depending on the knitted fabric, is a course without the needle bed racking.

  Therefore, in courses where the needle bed is not racked, it is conceivable to turn off the brake by the servo motor (servo brake) and fix the needle bed with another brake. However, the inventor has studied this point, and sliding force may be applied to the needle bed from the knitted fabric or carriage, and even if the course is not racked, the needle bed may move inadvertently when braking with a brake. I found. Moreover, in the braking by the brake, it cannot be returned to the original position after the needle bed has moved. Then, knitting is continued while the needle bed is placed at a position different from the knitting data. On the other hand, the servo brake can be returned to the original position. In what conditions for this, it is necessary to consider whether to switch a servo brake and other brakes.

  Regarding a robot or the like, it is known that a brake different from the servomotor is provided and the servomotor is turned off and the brake is turned on during a period in which the shaft is not driven by the servomotor (Patent Document 1: JP2000-308990A). . This eliminates the need for excitation of the servo motor, thereby saving power. However, in the case of a flat knitting machine, if the servo motor is switched to the brake simply by not driving the shaft by the servo motor, that is, not racking, the needle bed is not effective due to the force from the knitted fabric or carriage as described above. May move in preparation.

JP2000-308990A

  An object of the present invention is to reduce the frequency of using a servo motor that racks the needle bed as a servo brake while preventing inadvertent movement of the needle bed, thereby saving power.

  The present invention includes at least a pair of front and back needle beds, and at least one needle bed is rackable with respect to the other needle bed along the longitudinal direction of the needle bed by a servo motor for racking and serving as a servo brake. In a flat knitting machine for knitting a knitted fabric by operating needles of a needle bed by a carriage that reciprocates on at least a pair of needle beds, a brake for prohibiting racking of a lacquerable needle bed and knitting data of the knitted fabric And a slide force calculation unit for obtaining a slide force applied to the rackable needle bed from the knitted fabric or the carriage. The sliding force here is a force applied to rack the needle bed from other than the servo motor, which causes the needle bed to move carelessly. When the obtained sliding force is equal to or less than a first predetermined value and the needle bed is not racked by the servomotor, the servomotor is de-energized and the brake is turned on, and the obtained sliding force is the first predetermined value. And an output interface for exciting the servo motor and turning off the brake when the needle bed is racked by the servo motor.

  The present invention also includes at least a pair of front and rear needle beds, and at least one of the needle beds is rackable with respect to the other needle bed along the longitudinal direction of the needle bed by a servo motor for racking and serving as a servo brake. The flat knitting machine performs racking of a freely lacable needle bed in order to control power saving of the flat knitting machine that knitted the knitted fabric by operating the needles of the needle bed with a carriage that reciprocates on the at least one pair of needle beds. A brake for prohibiting is provided, and a step for obtaining a sliding force applied to the rackable needle bed from the knitted fabric or carriage based on the knitting data of the knitted fabric, and the obtained sliding force is equal to or less than a first predetermined value And when the needle bed is not racked by the servo motor, the excitation of the servo motor is released and the brake is turned on, and the obtained sliding force In a power saving control method for a flat knitting machine, executing a step of exciting the servo motor and turning off the brake when the first predetermined value is exceeded and when the needle bed is racked by the servo motor. is there.

  In the present invention, the sliding force applied from the knitted fabric or the carriage to the needle bed that can be racked is obtained. In the present invention, switching between braking by a servo motor or braking by another brake is performed, and specifically, the sliding force is determined in order to determine whether or not the other bed can suppress the sliding force by suppressing the sliding force. Ask. Accordingly, the accuracy of the required sliding force may be such that this determination can be made. When the obtained sliding force is equal to or less than the first predetermined value and the needle bed is not racked by the servo motor, the servo motor is de-energized and the brake is turned on. The power consumption can be reduced by releasing the excitation. Also, when the sliding force exceeds the first predetermined value and when the needle bed is racked by the servo motor, the servo motor is excited and the brake is turned off, so the servo motor is always excited when necessary. . Furthermore, since the servo motor or another brake is switched based on the knitting data, the control in anticipation can be performed. In other words, it is possible not only to discriminate whether the brake by the servo motor is appropriate at each time point or whether another brake is appropriate, but also the situation can be predicted in the next course or the next next course, so that more rational control can be performed. The switching of the brake may be performed in course units or in the course of the course. For example, the servo motor is used as a brake in a section where the sliding force is not less than the first predetermined value in the course, and a brake other than the servo motor is used in other sections in the course. Anyway.

  The slide force can be obtained by an apparatus other than a flat knitting machine such as a knit design system based on the knitting data. Further, whether or not the obtained sliding force is equal to or less than the first predetermined value and whether or not the needle bed is racked by the servo motor can also be obtained by the knit design system based on the knitting data. Therefore, in the knit design system, it is decided whether to use the brake by the servo motor or another brake, and memorize it in the flat knitting machine, and switch between the brake by the servo motor and the other brake by the output interface of the flat knitting machine. Also good.

The brake is preferably a non-excited brake that is turned off by energization and turned on by de-energization. If it does in this way, the power consumption at the time of turning on a brake will not generate | occur | produce, but it can further aim at power saving.
Preferably, the sensor further includes a sensor for measuring a sliding force such as a strain gauge, and the output interface prohibits the release of excitation of the servo motor when the sliding force obtained by the sensor is equal to or greater than a second predetermined value. At the same time, turn off the brake. The sliding force acting on the needle bed can be obtained from the knitting data. However, if the force applied to the needle bed is monitored with a strain gauge or the like, the slide force actually applied to the needle bed can be obtained, and it is possible to cope with an unexpected load. The second predetermined value may be the same as or different from the first predetermined value. For example, when the control based on the knitting data is a principle and the control based on the sensor is considered as a backup safety means, the second predetermined value is set larger than the first predetermined value.

Preferably, the sliding force calculating unit obtains a sliding force applied from the carriage to the needle bed based on the traveling speed of the carriage and the number of selected needles in a rack bed that can be freely racked. The force applied from the carriage to the needle bed increases as the number of selected needles increases, and the force applied from the carriage to the needle bed increases as the traveling speed of the carriage increases. Therefore, the sliding force can be obtained from the traveling speed of the carriage and the number of selected needles.
Particularly preferably, the sliding force calculating unit applies the sliding force applied from the knitted fabric to the needle bed based on the number of pitches that the rackable needle bed is racked and the number of knitting yarns passing between the front and back needle beds. Ask for. The number of knitting yarns that cross between the front and back needle beds represents the degree to which the front and back needle beds are connected to each other by the knitting yarns, and the number of racking pitches is the force with which each yarn tries to rack the needle beds. Represents. Therefore, the force with which the knitted fabric racks the needle bed can be obtained from the number of pitches that the rack bed that can be racked is racked and the number of knitting yarns that cross between the front and back needle beds.

  Also preferably, the slide force calculated from the knitting data by the slide force calculation unit is calculated from the excitation current value of the servo motor or the output torque of the servo motor when the knitted fabric is knitted by exciting the servo motor. A correction unit is provided that changes the first predetermined value when the measured sliding force differs from the sliding force obtained from the knitting data by a predetermined condition or more compared to the force.

  When the flat knitting machine is cold at the start, a sliding force larger than the sliding force obtained from the knitting data may act on the needle bed. In addition, when dust accumulates in the needle grooves of the flat knitting machine, a sliding force larger than the sliding force obtained from the knitting data may act on the needle bed. On the contrary, when the flat knitting machine is warmed up for a long time after the start of knitting and the needle grooves are cleaned cleanly, only a sliding force smaller than the sliding force obtained from the knitting data may work.

Therefore, for example, the servomotor is excited for about 1 to 2 courses at the start of knitting, for example, knitting is performed with the maximum number of needles selected, and the sliding force applied to the servomotor from the needle bed during this time is measured. The carriage speed during this period may be constant, for example, or may be changed between several speeds. The sliding force applied to the needle bed can be measured from the value of the excitation current of the servo motor or the output torque of the servo motor. And, for example, when the ratio or difference between the measured slide force and the slide force calculated from the knitting data is obtained and this ratio is deviated from 1 or more by a predetermined condition, or the absolute value of the difference is deviated by more than a predetermined condition The first predetermined value relating to the sliding force obtained from the knitting data is changed. For example, if the measured slide force is greater than the slide force obtained from the knitting data by a predetermined condition or more, the first predetermined value is decreased.

Schematic plan view of the flat knitting machine of the embodiment Block diagram of the power saving control unit in the embodiment Diagram showing the sliding force applied from the carriage to the needle bed Diagram showing the sliding force applied from the knitting yarn to the needle bed

  In the following, an optimum embodiment for carrying out the invention will be shown. The scope of the present invention should be construed in consideration of the possibility of modification by well-known techniques in the description of the scope of claims.

  1 to 4 show a flat knitting machine 2 according to an embodiment. In FIG. 1, reference numeral 4 denotes a front needle bed and reference numeral 6 denotes a rear needle bed, each of which includes a large number of knitting needles, and there is a mouth 8 between the needle beds 4 and 6. Here, the rear needle bed 6 is rackable in the left-right direction in FIG. 1 and the front needle bed 4 is fixed, but both may be rackable. Further, the present invention may be applied to a flat knitting machine such as a four-needle bed provided with needle beds or transfer member beds before and after the upper and lower sides. In that case, the four needle beds and the like are divided into front and rear, and the two needle beds on the front and rear are preferably racked.

  The carriage 10 reciprocates left and right in FIG. 1 on the needle beds 4 and 6, and one stroke is called one course or one knitting course. The carriage 10 selects the needles of the needle beds 4 and 6, and operates by controlling the bat of the selected needle with a cam. At this time, a sliding force acts on the rear needle bed 6 from the carriage 10 through the needle. A toothed belt 12 is driven by a carriage driving servomotor (not shown), and a racking servomotor 14 is also used as a servo brake to rack the rear needle bed 6. Reference numeral 15 denotes a sensor for measuring a sliding force, for example, a strain gauge provided on a needle bed or a shaft of a servo motor. When a strain gauge is used as the sensor 15, the sliding force can be obtained even when the servo motor is off. The sensor 15 may be a current sensor that monitors the value of the excitation current of the servo motor 14 or a sensor that measures the output torque of the servo motor 14. However, when the servo motor is off, there is an unexpected load from the knitting data. If you join, you can not respond.

  A brake 16 is a type that operates as a brake without excitation, and the brake action is released by excitation. The structure of the brake 16 is shown in the lower left of FIG. Reference numeral 20 denotes a shaft. A screw (not shown) is engraved in the center portion, meshes with a nut provided on the rear needle bed 6, and when the shaft 20 is rotated by the servo motor 14, the rear needle bed racks to the left and right. 22 is a brake disk, 24 is an exciting coil, 26 is a spring, and 27 is a friction plate. When the coil 24 is excited, the friction plate 27 overcomes the repulsive force of the spring 26 and is separated from the brake disk 22 to release the brake. The When energization of the coil 24 is stopped, the friction plate 27 is pressed against the brake disc 22 by the repulsive force of the spring 26, and the brake is turned on. Therefore, there is no power consumption when the brake is on, and power is consumed when the brake is released.

  The control unit 18 of the flat knitting machine stores and analyzes the knitting data, and controls the servo motor 14 control signal, the brake 16 control signal, the carriage movement control signal, and the needle selection device and cam control signal in the carriage. Is output. The power saving control unit 30 of the embodiment is provided in the control unit 18.

  In FIG. 2, reference numeral 30 denotes a power saving control unit, and reference numeral 32 denotes a knitting data storage unit, which stores knitting data of the knitted fabric. The knitting data analyzing unit 34 analyzes the knitting data before executing each knitting course. For example, before starting the knitting, the knitting data analyzing unit 34 reads ahead and analyzes all the knitting courses. The object of analysis is the racking state, that is, how many pitches the rear needle bed 6 is racked with respect to the front needle bed 4 in the left and right direction, the number of knitting yarns, that is, between the front and back needle beds. The number of knitting yarns that cross The pitch is the distance between the needles in the needle bed. As the original racking state, for example, the racking state between the front and back needle beds at the time when the stitch is formed is stored, but this data may be ignored. Further, the loop length of the stitch is obtained from the knitting data, and if necessary, the material, thickness, etc. of the knitting yarn are stored as data other than the knitting data. These data are stored in the storage unit 36.

  The correction unit 37 calculates the sliding force obtained from the knitting data and the sliding force measured from the excitation current value of the servo motor 14 or the output torque of the servo motor when the knitted fabric is knitted by exciting the servo motor 14. When the measured slide force differs from the slide force obtained from the knitting data by a predetermined condition or more, the first predetermined value is changed, and the changed first predetermined value is stored.

  When the flat knitting machine 2 is cold at the start, a sliding force larger than the sliding force obtained from the knitting data may act on the rear needle bed 6. Further, even when dust accumulates in the needle groove of the flat knitting machine 2, a sliding force larger than the sliding force obtained from the knitting data may act on the rear needle bed 6. On the contrary, when the flat knitting machine 2 is warmed up for a long time after the start of knitting and the needle grooves are cleaned cleanly, only a sliding force smaller than the sliding force obtained from the knitting data may work.

  Therefore, for example, the servomotor is excited for about 1 to 2 courses at the start of knitting, for example, knitting is performed with the maximum number of needles selected, and the sliding force applied to the servomotor from the needle bed during this time is measured. The carriage speed during this period may be constant, for example, or may be changed between several speeds. This knitting does not need to be performed for each knitted fabric. For example, at the start of every day, the knitting machine 2 adjusts the cam of the carriage 10 so that the flat knitting machine 2 can knitting stitches having a size according to the knitting data. This should be done at the same time as the routine. The sliding force applied to the rear needle bed 6 can be measured from the value of the excitation current of the servo motor 14 or the output torque of the servo motor 14. When knitting is performed in order to measure the sliding force applied from the knitting needle to the servomotor at the start of knitting or the like, empty knitting in which the needle is moved up and down without using the knitting yarn may be used.

  When the ratio or difference between the measured slide force and the slide force calculated from the knitting data is obtained, and this ratio deviates from 1 or more by a predetermined condition, or the absolute value of the difference deviates by more than a predetermined condition, knitting The first predetermined value relating to the sliding force obtained from the data is changed. For example, if the measured slide force is greater than the slide force obtained from the knitting data by a predetermined condition or more, the first predetermined value is decreased. On the other hand, when it is smaller than the predetermined condition, the first predetermined value may be increased, or the first predetermined value may not be changed.

  The storage unit 38 stores elements relating to the sliding force acting on the rear needle bed 6 from the carriage 10. These elements include the number of needles selected from the rear needle bed 6 and the carriage speed. The sliding force is a force for racking the rear needle bed 6 in the left-right direction, and there are one that works from the carriage 10 and one that works from the knitted fabric. If the stitch is racked to the left and right with respect to the position at the time of formation due to the racking of the rear needle bed 6, a sliding force acts on the rear needle bed 6 from the knitting yarn. This force becomes stronger as the number of knitting yarns extending between the front and back needle beds 4 and 6 increases, and becomes stronger as the distance (number of pitches) by which the stitch is racked to the left and right is larger than when the stitch is formed. . Furthermore, since the loop length of the stitch is small, it becomes strong even when the tension of the knitting yarn is high or the material is thick and hard. Note that the current racking distance may be simply used instead of the racking distance based on the time when the stitch is formed. The slide force calculation units 40 and 42 convert these data into a slide force from the knitted fabric using an appropriate table, map, function, or the like.

  The sliding force calculation unit 42 calculates the sliding force applied from the carriage 10 to the rear needle bed from the carriage traveling speed and the number of stitches. That is, the carriage controls the bat of the needle with a cam, and at this time, the bat is pushed by the carriage 10 to generate a sliding force. Here, when the transition from the state where the influence of the carriage is small (the carriage is inversion or few needles are selected) to the state where a large number of needles are selected at the knitting portion or the like, the sliding force suddenly works. The rear needle bed 6 may be racked. Similarly, the sliding force works even if the number of needles selected suddenly changes during the course. These sliding forces increase as the traveling speed of the carriage increases. The racking command storage unit 44 stores the presence / absence of a racking command.

  The determination unit 46 adds the sliding force obtained by the sliding force calculation units 40 and 42. The sliding force has a direction. The servo motor 14 is turned on unconditionally and the brake 16 is turned off unconditionally in the course of racking and each of the first and second courses before and after the course. The servo motor 14 is turned off (excitation is released) and the brake 16 is turned on (also excited) in the course other than the first predetermined value and the course in which racking is performed and courses other than 1-2 courses before and after that. Cancel). The first predetermined value is corrected by the correcting unit 37. In this way, which of the servo motor 14 and the brake 16 is turned on is stored in the storage unit 48 in units of courses.

  The output interface 50 monitors the knitting progress, reads data from the storage unit 48, for example, one course before executing each course, and if the sliding force obtained by the sensor 15 is equal to or less than the second predetermined value. The servo motor 14 and the brake 16 are controlled according to the data in the storage unit 48. If the sliding force exceeds the second predetermined value, the rear needle bed 6 is performing racking, or a force that causes the rear needle bed 6 to be inadvertently racked for some reason is applied. The motor 14 is turned on and the brake 16 is turned off.

  Steps 1 to 4 in FIG. 3 show a mechanism in which the rear needle bed 6 is pushed by the carriage 10. When the carriage is reversed and needle selection starts, the bat of the needle is operated and pushed by the carriage, and a sliding force is applied. This force is proportional to the number of needles operated by the carriage 10 at the knitting portion. In addition, when the number of needles selected per predetermined length changes during the course, a sliding force proportional to the change in the number of needles works.

  FIG. 4 shows a mechanism of the sliding force that works from the knitted fabric. Reference numeral 52 denotes a transition yarn between the front and back needle beds 4 and 6, 54 denotes a stitch of the front needle bed 4, and 55 denotes a stitch of the rear needle bed 6. In FIG. 4, the stitch 55 racks to the right side when viewed from the front, and a force that racks the rear needle bed 6 to the left side in FIG. This force is proportional to the number of crossover yarns 52, is proportional to the racking distance from the formation of the stitch 55, and is stronger as the loop length of the stitch 55 is shorter. Therefore, the sliding force working from the knitted fabric can be calculated from these factors.

In the embodiment, the following effects can be obtained.
1) When there is no possibility that the rear needle bed 6 is inadvertently racked, the servo motor 14 is turned off and the excitation of the brake 15 is released to save power.
2) Switching data between the servo motor 14 and the brake 16 can be obtained in advance from the knitting data.
3) The sliding force actually acting on the rear needle bed is obtained from the sensor 15, and when the sliding force is large, the servo motor 14 is turned on.
4) Control can take into account both sliding force from the carriage and sliding force from the knitted fabric.
2 may be provided in a knit design system (not shown) from the knitting data storage unit 32 to the determination unit 46, and the flat knitting machine 2 may be provided with only the storage unit 48 and the output interface 50 in FIG.

2 Flat knitting machine 4 Front needle bed 6 Rear needle bed 8 Tooth mouth 10 Carriage 12 Belt 14 Servo motor 15 Sensor 16 Brake 18 Control unit 20 Shaft 22 Brake disk 24 Coil 26 Spring 27 Friction plate 30 Power saving control unit 32 Knitting data storage Unit 34 knitting data analysis unit 36, 38 storage unit 40, 42 sliding force calculation unit 44 racking command storage unit 46 determination unit 47 correction unit 48 storage unit 50 output interface 52 crossover yarns 54, 55 stitches

Claims (9)

At least one pair of front and rear needle beds is provided, and at least one needle bed is rackable to the other needle bed by a servo motor that is used for racking and also serves as a servo brake, and can be racked along the longitudinal direction of the needle bed. In a flat knitting machine for knitting a knitted fabric by operating needles of a needle bed with a carriage reciprocating on the needle bed of
A brake to prohibit racking of the free needle bed,
Based on the knitting data of the knitted fabric, a sliding force calculating unit for obtaining a sliding force applied to the lacquerable needle bed from the knitted fabric or the carriage,
When the obtained sliding force is equal to or less than a first predetermined value and the needle bed is not racked by the servomotor, the servomotor is de-energized and the brake is turned on, and the obtained sliding force is the first predetermined value. A flat knitting machine comprising: an output interface for exciting the servo motor and turning off the brake when exceeding the value and racking the needle bed by the servo motor.   The flat knitting machine according to claim 1, wherein the brake is a non-excited brake that is turned off by energization and turned on by de-energization.   The sensor further includes a sensor for measuring the sliding force, and the output interface has a sliding force obtained by the sensor that is equal to or greater than a second predetermined value, prohibits the servo motor from being de-energized, and turns off the brake. The flat knitting machine according to claim 1 or 2, characterized in that.   The slide force calculation unit obtains a slide force applied to the needle bed from the carriage based on the traveling speed of the carriage and the number of selected needles, in a rack bed that can be freely racked. 2 flat knitting machines.   The slide force calculating unit obtains a slide force applied to the needle bed from the carriage based on a traveling speed of the carriage and the number of selected needles in a rack bed that can be freely racked. Flat knitting machine.   The sliding force calculation unit obtains the sliding force applied from the knitted fabric to the needle bed based on the number of pitches that the rack bed that can be racked is racked and the number of knitting yarns that cross between the front and back needle beds. The flat knitting machine according to claim 4, wherein the flat knitting machine is characterized.   The sliding force calculation unit obtains the sliding force applied from the knitted fabric to the needle bed based on the number of pitches that the rack bed that can be racked is racked and the number of knitting yarns that cross between the front and back needle beds. The flat knitting machine according to claim 5, wherein the flat knitting machine is characterized.   When the knitted fabric is knitted by exciting the servo motor, the sliding force measured from the value of the exciting current of the servo motor or the output torque of the servo motor is calculated with the sliding force obtained from the knitting data by the sliding force calculator. The correction unit is provided for changing the first predetermined value when the measured sliding force is different from the sliding force obtained from the knitting data by a predetermined condition or more. 2 flat knitting machines. At least one pair of front and rear needle beds is provided, and at least one needle bed is rackable to the other needle bed by a servo motor that is used for racking and also serves as a servo brake, and can be racked along the longitudinal direction of the needle bed. In order to control power saving of a flat knitting machine that knits the knitted fabric by operating the needles of the needle bed with a carriage that reciprocates on the needle bed,
The flat knitting machine is equipped with a brake to prohibit racking of the needle bed that can be racked freely,
Based on the knitting data of the knitted fabric, a step for obtaining a sliding force applied to the lacing-free needle bed from the knitted fabric or carriage;
When the obtained sliding force is equal to or less than a first predetermined value and the needle bed is not racked by the servomotor, the servomotor is de-energized and the brake is turned on, and the obtained sliding force is the first predetermined value. A power saving control method for a flat knitting machine, wherein when the value is exceeded and when the needle bed is racked by the servo motor, the servo motor is excited and the brake is turned off.

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