JP2018187056A - sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly perform a vertical reciprocation operation of a feed dog.SOLUTION: In a sewing machine 100, a feed operation is added to a feed dog 31 for feeding a workpiece, by combining a reciprocation operation of a feed direction component and a reciprocation operation of a vertical direction component. The sewing machine includes: a sewing machine motor 16 which serves as a driving source of the reciprocation operation of the feed direction component; a vertical feed motor 66 which serves as a driving source of the reciprocation operation of the vertical direction component; a cloth presser 13 for pressing the workpiece on a needle plate 11; a detection part 161 for detecting the height of the feed dog; and a motor control device 90 for controlling the vertical feed motor so that the feed dog performs feeding at target height. The motor control device stores a plurality of control parameters regarding responsiveness of the vertical feed motor, and performs control of the vertical feed motor by switching the control parameters according to the detection height of the feed dog by the height detection part.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a sewing machine that performs feed adjustment.

Conventionally, the sewing machine uses the torque of the sewing machine motor as a drive source for the reciprocating motion in the vertical direction of the feed dog and the reciprocating motion in the horizontal direction (feeding direction).
Then, the feed adjustment motor for changing the operation transmission amount to the feed adjustment body provided in the transmission mechanism for transmitting the horizontal reciprocation operation from the sewing machine motor to the feed dog is controlled to arbitrarily set the feed amount. It was possible to change and adjust (see, for example, Patent Document 1).

JP 2010-246839 A

As described above, the sewing machine that drives the feed dog in the vertical direction and the horizontal direction by a single drive source can change the feed pitch, but it can change the shape of the trajectory around the feed dog. It is difficult to change arbitrarily, and for example, it is not possible to perform good feeding on fabrics having different thicknesses and flexibility.
For this reason, in recent years, it has been studied to mount a vertical feed motor independent of the horizontal reciprocation for the vertical reciprocation of the feed dog.

Since the vertical feed motor needs to give the feed dog up and down reciprocating movement in synchronization with the drive of the sewing machine motor, it detects the rotation of the output shaft and upper shaft of the sewing machine motor and feeds back to follow this. Control is performed.
Accordingly, when the feed dog is pressed from above by the cloth presser while the drive of the vertical feed motor follows the drive of the sewing machine motor, a load is applied to the vertical feed motor, so the load is applied. Control parameters for feedback control are set so that the machine motor can be tracked in the state.

On the other hand, during various adjustment operations such as adjustment of feed dog operation, adjustment operations such as idle feed may be performed by driving the sewing machine motor and vertical feed motor with the feed dog retracted upward. is there.
In such an upward retracted state of the cloth presser, the load on the vertical feed motor is reduced, so that the acceleration of the upward movement of the feed dog is increased, so-called overshoot occurs. There was a risk of collision with the lower surface side of the plate.

  An object of the present invention is to properly perform the up and down reciprocation of the feed dog.

The invention according to claim 1 is a sewing machine,
In the sewing machine that combines the reciprocating motion of the feed direction component and the reciprocating motion of the vertical component to the feed dog that feeds the workpiece,
A motor serving as a drive source for the reciprocating operation of the feed direction component;
A vertical feed motor serving as a drive source for the reciprocating motion of the vertical component;
A cloth presser that holds the workpiece on the needle plate,
A height detector for detecting the height of the feed dog;
A motor control device that controls the vertical feed motor so that the feed dog feeds at a target height;
The motor control device stores a plurality of control parameters related to the responsiveness of the vertical feed motor, and switches the control parameter according to the detected height of the feed dog by the height detection unit to control the vertical feed motor. Control is performed.

The invention according to claim 2 is the sewing machine according to claim 1,
The motor control device stores a threshold value that exceeds a target height of the feed dog, and switches the control parameter to change the upper and lower values when the detected height of the feed dog by the height detection unit exceeds the threshold value. The feed motor is controlled.

The invention according to claim 3 is the sewing machine according to claim 1 or 2,
The height detection unit is an encoder that outputs a change in the shaft angle of the output shaft of the vertical feed motor.

The invention according to claim 4 is a sewing machine,
In the sewing machine that combines the reciprocating motion of the feed direction component and the reciprocating motion of the vertical component to the feed dog that feeds the workpiece,
A motor serving as a drive source for the reciprocating operation of the feed direction component;
A vertical feed motor serving as a drive source for the reciprocating motion of the vertical component;
A cloth presser that holds the workpiece on the needle plate,
A height detector for detecting the height of the feed dog;
A current detection unit for detecting a current value flowing through the vertical feed motor;
A motor control device that controls the vertical feed motor so that the feed dog feeds at a target height;
The motor control device stores a plurality of control parameters related to the responsiveness of the vertical feed motor, and controls the vertical feed motor by switching the control parameter according to a current value flowing through the vertical feed motor. Features.

The invention according to claim 5 is the sewing machine according to claim 4,
The motor control device stores a threshold value of a current flowing through the vertical feed motor,
In the angular section of the upper shaft where the feed dog protrudes from the needle plate, when the detected current value flowing through the vertical feed motor by the current detection unit is less than or equal to the threshold value, the control parameter is switched to switch the vertical feed motor. Control is performed.

The invention according to claim 6 is the sewing machine according to claim 4 or 5,
The motor control device is characterized in that the control parameter is switched in accordance with a current value flowing through the vertical feed motor during non-sewing.

  As described above, according to the present invention, it is possible to appropriately move the feed dog up and down regardless of fluctuations in the pressing pressure of the cloth presser.

It is a perspective view which shows the main structures in the sewing machine bed part of the sewing machine which is 1st embodiment. It is a perspective view of a feed adjustment mechanism. It is a perspective view of a vertical feed mechanism. It is operation | movement explanatory drawing of the vertical feed mechanism at the time of the shaft angle of a vertical feed motor 0 degree. It is operation | movement explanatory drawing of the vertical feed mechanism at the time of the shaft angle of -10 degrees of a vertical feed motor. It is operation | movement explanatory drawing of the vertical feed mechanism at the time of the shaft angle +10 degree of a vertical feed motor. It is a block diagram which shows a motor control apparatus and the surrounding structure. It is a diagram which shows the various signals at the time of lowering a cloth presser and driving a vertical feed motor. It is a diagram which shows the various signals at the time of driving a vertical feed motor by retracting the cloth presser upward. It is a flowchart which shows operation control of the up-and-down feed motor by a motor control apparatus. It is a block diagram of the motor control device of the sewing machine of the second embodiment. It is a flowchart which shows operation control of the up-and-down feed motor by the motor control apparatus of 2nd embodiment. It is a flowchart which shows the process of pressing pressure detection mode.

[First embodiment]
Hereinafter, the sewing machine which is the first embodiment of the present invention will be described in detail.
FIG. 1 is a perspective view showing a main configuration in the sewing machine bed portion of the sewing machine 100.
As shown in FIG. 1, a sewing machine 100 is illustrated in which a needle up / down movement mechanism (not shown) that moves a sewing needle up and down, a sewing machine motor 16 (see FIG. 7) that is a driving source thereof, and a rotation operation by the sewing machine motor 16. The upper shaft, the hook 12 that entangles the upper thread with the lower thread, the needle plate 11, the cloth presser 13 that presses the sewing product from above on the upper surface of the needle plate 11, and the needle plate 11 in accordance with the vertical movement of the sewing needle. A feeding device 30 for feeding the upper cloth, a belt mechanism 20 for transmitting a rotational force from the upper shaft to the lower shaft 33 of the feeding device 30, a sewing machine frame (not shown) for supporting the above components, and a sewing machine; And a motor control device 90 (see FIG. 7) for controlling a plurality of motors including the motor 16.
The sewing machine 100 is a so-called lockstitch sewing machine, and includes various components such as a balance mechanism and a thread tension provided in a general lockstitch sewing machine.

The sewing machine frame includes a bed portion positioned at a lower portion of the entire sewing machine, a standing body portion that is erected upward at one end portion in the longitudinal direction of the sewing machine bed portion, and the same direction as the bed portion from the upper end portion of the standing body portion. And an arm portion (not shown) extending in the direction.
In the following description, the horizontal direction parallel to the longitudinal direction of the sewing machine bed is defined as the Y-axis direction, the horizontal direction orthogonal to the Y-axis direction is defined as the X-axis direction, and is orthogonal to the X-axis and Y-axis directions. Let the direction be the Z-axis direction.
The sewing machine 100 feeds the workpiece along the X-axis direction.

[Needle vertical movement mechanism and belt mechanism]
The needle up-and-down moving mechanism is disposed on the inner side of the arm portion, is rotationally driven by the sewing machine motor 16 and is disposed along the Y-axis direction, a needle bar that holds the sewing needle at the lower end portion, And a crank mechanism (not shown) that converts the rotational force of the upper shaft into a reciprocating drive force that moves up and down and transmits it to the needle bar.
The belt mechanism 20 includes a main driving pulley fixedly mounted on the upper shaft, a driven pulley 21 fixedly mounted on the lower shaft 33 of the feeding device 30, and a timing belt 22 stretched between the main driving pulley and the driven pulley 21. And. The lower shaft 33 rotates at the same speed as the upper shaft by the belt mechanism 20.
Instead of the belt mechanism, a rotational force may be transmitted from the upper shaft to the lower shaft 33 by a gear transmission mechanism including a vertical axis and a bevel gear.

[Feeding device]
As shown in FIG. 1, the feeding device 30 obtains power from a feed dog 31 that appears and disappears from the opening of the needle plate 11 and feeds the fabric in a predetermined direction, a feed base 32 that holds the feed dog 31, and the sewing machine motor 16. The lower shaft 33 that rotates and rotates, the horizontal feed mechanism 40 as a feed mechanism that transmits the reciprocating motion in the X-axis direction (horizontal direction) along the cloth feed direction to the feed base 32, and the feed base 32 An up / down feed mechanism 60B that provides a reciprocating motion in the up / down direction is provided.

[Horizontal feed mechanism]
The horizontal feed mechanism 40 includes a feed adjustment mechanism 50 that adjusts a feed amount that is a stroke of a reciprocating operation in the X-axis direction with respect to the feed base 32, a crank rod 41 that extracts a reciprocating operation along the X-axis direction from the lower shaft 33, A horizontal feed shaft 42 to which reciprocating rotation is applied from the crank rod 41 via the feed adjusting mechanism 50, and a reciprocating driving force of the horizontal feed shaft 42 is converted into a reciprocating driving force in the feeding direction and transmitted to the feed base 32. The horizontal feed arm 43 is provided.

  One end of the crank rod 41 rotatably holds an eccentric cam (not shown) fixed to the lower shaft 33, and the other end is connected to the feed adjusting mechanism 50. The crank rod 41 is arranged so that its longitudinal direction is generally along the X-axis direction. When the lower shaft 33 is driven at full rotation, the other end of the crank rod 41 is doubled by the eccentric cam. The reciprocating motion is performed along the longitudinal direction with a stroke of. The reciprocating motion of the crank rod 41 is transmitted as reciprocating power to the horizontal feed shaft 42 via the feed adjusting mechanism 50.

  As shown in FIG. 2, the feed adjusting mechanism 50 is fixedly mounted on the horizontal feed shaft 42 and extends outward in the radial direction with the horizontal feed shaft 42 as the center. A pair of first link bodies 53 that connect the end portion and the swing arm 51, a pair of second link bodies 54 that guide the reciprocating motion direction of the other end portion of the crank rod 41 in either direction, A feed adjustment body 55 that determines the guiding direction by the second link body 54, a support shaft 52 that rotates integrally with the feed adjustment body 55, a fixed attachment to the support shaft 52, and the support shaft 52 as a center. An input arm 56 extended outward in the radial direction and a feed adjustment motor that rotates the feed adjustment body 55 to adjust the amount of reciprocation in the X-axis direction (horizontal direction) transmitted from the lower shaft 33 to the feed base 32. 57 and the output of the feed adjustment motor 57 And a two transmission links 58 and 59 for transmitting the input arm 56 twice power from.

The first link body 53 has one end connected to the other end of the crank rod 41 and the other end connected to the swing end of the swing arm 51, both of which rotate around the Y axis. It is linked movably.
One end of the second link body 54 is connected to the other end of the crank rod 41 together with one end of the first link 53, and the other end is connected to the rotating end of the feed adjusting body 55. Both end portions are connected so as to be rotatable about the Y axis.
The feed adjusting body 55 is fixedly equipped with a support shaft 52 along the Y-axis direction at the base end portion, and the support shaft 52 is supported so as to be rotatable around the Y-axis in the sewing machine frame.
Further, the rotation end portion of the feed adjusting body 55 is connected to the other end portion of the second link body 54 so as to be rotatable around the Y axis.

  In the feed adjustment mechanism 50, the longitudinal directions of the first link body 53 and the second link body 54 coincide with each other, that is, the link bodies 53 and 54 overlap each other when viewed from the Y-axis direction. When the feed adjusting body 55 is rotated, the driving force of the crank rod 41 is not transmitted to the swing arm 51. At this time, since the reciprocating motion is not transmitted to the horizontal feed shaft 42, the reciprocating stroke of the feed base 32 in the X-axis direction is zero, that is, the feed amount is zero. In this way, the rotation angle of the feed adjusting body 55 in which the link bodies 53 and 54 overlap each other is defined as a “neutral angle of the feed adjusting body 55”.

Then, when the feed adjusting body 55 is rotated from the neutral angle to one side, a reciprocating swinging operation is given to the swinging arm 51 side according to the rotation angle amount, thereby reducing the feed amount in the forward feed direction. Can be bigger.
Further, when the feed adjusting body 55 is rotated in the reverse direction from the neutral angle, a reciprocating swinging operation can be imparted to the swinging arm 51 side according to the rotational angle amount. Is transmitted with the phase reversed, which can increase the feed amount in the reverse feed direction.

The feed adjusting motor 57 is arranged with the output shaft directed in the Y-axis direction on one end side in the Y-axis direction inside the sewing machine bed portion. One end of the transmission link 58 is fixed to the output shaft of the feed adjustment motor 57 with its longitudinal direction being substantially in the X-axis direction. Accordingly, the other end portion of the transmission link 58 rotates up and down by driving the feed adjusting motor 57.
The transmission link 59 has a lower end connected to the other end of the transmission link 58 so as to be rotatable about the Y axis in a state where the longitudinal direction thereof is substantially along the Z-axis direction. Accordingly, the transmission link 59 moves up and down as a whole by driving the feed adjusting motor 57.
The input arm 56 is fixedly mounted on the support shaft 52 and extends substantially along the X-axis direction from the support shaft 52, and its extended end rotates around the Y axis at the upper end of the transmission link 59. Connected as possible.
Accordingly, when the feed adjusting motor 57 is driven, the feed adjusting body 55 can be rotated via the transmission links 58 and 59 and the input arm 56.

  The horizontal feed shaft 42 is supported so as to be rotatable along the Y-axis direction in the sewing machine bed portion, and is disposed downstream of the lower shaft 33 in the cloth feed direction (left side in FIG. 1). A reciprocating power is applied from the lower shaft 33 to the one end of the horizontal feed shaft 42 on the vertical barrel side via the feed adjusting mechanism 50 described above, and from the other end of the horizontal feed shaft 42 via the horizontal feed arm 43. The reciprocating motion along the X-axis direction is transmitted to the feed base 32.

The base end of the horizontal feed arm 43 is fixedly connected to the end of the horizontal feed shaft 42 on the needle plate 11 side, and the swinging end thereof is connected to the feed base 32 in a state of being directed substantially upward. .
Accordingly, the horizontal feed arm 43 can reciprocate the feed base 32 along the X-axis direction by driving the sewing machine motor 16. Further, the stroke of the reciprocating operation along the X-axis direction of the feed base 32 can be arbitrarily adjusted by controlling the feed adjustment motor 57 of the feed adjustment mechanism 50.

The feed base 32 is disposed below the needle plate 11, one end in the cloth feed direction (X-axis direction) is connected to the vertical feed mechanism 60 </ b> B, and the other end is connected to the horizontal feed arm 43. Further, a feed dog 31 is fixedly installed at the upper part of the intermediate position in the longitudinal direction of the feed base 32.
Thus, the feed base 32 is given a reciprocating drive force in the vertical direction from one end thereof, and a reciprocating drive force in the feed direction is given from the other end in the same cycle. Then, by combining these reciprocating driving forces, an ellipse motion is performed along the XZ plane. The feed dog 31 also performs an ellipse motion along with the feed base 32, and the tip of the feed dog 31 protrudes upward from the opening of the needle plate 11 when moving along the upper region of the ellipse motion trajectory. It is possible to send.

[Vertical feed mechanism]
FIG. 3 is a perspective view of the vertical feed mechanism 60B, and FIGS. 4 to 6 are operation explanatory views of the vertical feed mechanism 60B.
The vertical feed mechanism 60B is connected to the vertical feed motor 66 serving as a drive source for the reciprocating operation in the vertical direction (Z-axis direction) with respect to the feed base 32, and is connected to the output shaft of the vertical feed motor 66 to perform a rotation operation. One link 61B, a second link 62B having one end connected to the rotating end of the first link 61B, a third link 63B having one end connected to the other end of the second link 62B, and a third A rotation shaft 67 coupled to the other end of the link 63B and fixed in position within the sewing machine frame; a fourth link 64 coupled to the third link 63B via the rotation shaft 67; A fifth link 65 having one end connected to the rotating end of the four links 64 and the other end connected to one end of the feed base 32 is provided.
In addition, it can be easily considered to change to a configuration using a motor, an eccentric cam, and a link, or a configuration using a motor, a rack, and a pinion instead of the vertical feed mechanism 60B.

The vertical feed motor 66 is disposed at the end on the needle plate 11 side in the Y-axis direction in the sewing machine bed portion, and is spaced apart from the feed adjustment motor 57 of the feed adjustment mechanism 50 described above in the Y-axis direction. Both of these motors 57 and 66 require a large installation space. Thus, the motors 57 and 66 are arranged in the sewing machine bed portion so as to be separated from each other in the longitudinal direction. Space can be secured.
The vertical feed motor 66 is arranged with its output shaft along the Y-axis direction.

Further, the vertical feed motor 66 uses a stepping motor having the same specifications and the same performance as the feed adjustment motor 57 described above, and the same model and type.
Thereby, it is possible to share the motor and its peripheral members, and it is possible to reduce costs and improve maintainability.

The first link 61 </ b> B is fixedly supported by the output shaft of the vertical feed motor 66 at the base end that is the center of rotation.
On the other hand, the other end of the third link 63B is fixedly supported by a rotating shaft 67 that is rotatably supported by a frame of the sewing machine bed portion.
The pivot end of the first link 61B and the pivot end of the third link 63B are connected to one end and the other end of the second link 62B so as to be rotatable about the Y axis.
And these 1st-3rd links 61B-63B are the states in which the 1st link 61B is substantially parallel to the Z-axis direction, and the rotation edge part has faced upwards, as shown in FIG. When the link 63B is substantially parallel to the Z-axis direction and the rotation end thereof is directed downward, the second link 62B has a respective length so that the second link 62B is in a horizontal state substantially parallel to the X-axis direction. Is set.

Accordingly, when the output shaft of the vertical feed motor 66 is the shaft angle (0 °) shown in FIG. 4, the first link 61B and the second link 62B are 90 ° (right angle). This state is the “origin” in the link row composed of the first to third links 61B to 63B.
At the shaft angle that is the “origin”, the height of the feed dog 31 coincides with the height of the upper surface of the needle plate 11.
Further, when the vertical feed motor 66 is rotationally driven in the reverse direction (counterclockwise) as shown in FIG. 5 with respect to the axis angle serving as the “origin”, the feed dog 31 rises from the upper surface of the needle plate 11, 6, when the vertical feed motor 66 is rotationally driven in the forward direction (clockwise), the feed dog 31 is lowered from the upper surface of the needle plate 11.
In the sewing machine 100, the motor control device 90 has the first link 61 </ b> B and the second link 62 </ b> B aligned on the same straight line with respect to the vertical feed motor 66 for the feed operation for one stitch by the feed dog 31. Operation control is performed in which the reciprocating rotation in the forward and reverse directions is performed once within an angle range that does not reach the output shaft angle in the maximum extension state (dead point) (for example, the origin ± 10 °).

  Thus, the link row composed of the first to third links 61B to 63B maintains the rotation operation of the vertical feed motor 66 and the application of the vertical motion to the feed base 32 at the same frequency, so that the horizontal direction Compared with the case where the reciprocating motion of feeding is applied by a motor independent of the sewing machine motor 16, the reciprocating stroke is small, and the followability to high-speed rotation sewing is excellent. In particular, the vertical feed motor 66 performs driving while avoiding an axial angle at which the first link 61B and the second link 62B are dead points, and further, the first link 61B and the second link 62B form a right angle. By performing the driving within the range including the shaft angle, the reciprocating stroke can be further reduced, and the followability to high-speed sewing can be further improved.

Further, the fourth link 64 is pivoted integrally with the third link 63B because the base end is fixed to the pivot shaft 67 in a state substantially along the X-axis direction.
The fifth link 65 has one end connected to the rotating end of the fourth link 64 and the other end connected to one end of the feed base 32 in a state substantially along the Z-axis direction. The vertical movement can be transmitted to the feed base 32 via the fifth link 65 by the rotation of the fourth link 64.

[Cloth presser]
As shown in FIG. 4 (not shown in FIGS. 5 and 6), the cloth presser 13 is disposed on the upper surface of the needle plate 11 directly above the protruding position of the feed dog 31, and the lower end of the presser bar 14. It is supported by.
The presser bar 14 is supported by the sewing machine arm portion so as to be movable up and down, and is pressed downward by a pressing spring (not shown). The compression length of the pressing spring can be adjusted by an adjusting screw provided on the upper portion of the presser bar 14, and the pressing pressure of the cloth presser 13 can be adjusted by the adjusting screw.
Further, the sewing machine arm portion is equipped with a press-up lever (not shown) that can pull up and hold the cloth presser 13 to the upper retracted position via the presser bar 14 by a turning operation.

[Motor control device]
The motor control device 90 and the surrounding configuration are shown in the block diagram of FIG.
As shown in FIG. 7, the motor control device 90 includes a microcomputer 91 and a memory 92, and the microcomputer 91 executes various operation controls to be described later according to various programs and various setting data stored in the memory 92. .
In addition, an operation input unit 93 for inputting selection, execution, and setting of various operation controls for the feeding device 30 to be described later is connected to the microcomputer 91 via an interface 93a.

The microcomputer 91 is connected to a sewing machine motor 16, a feed adjusting motor 57, and a vertical feed motor 66 via respective motor drivers 16a, 57a, 66a.
The sewing machine motor 16, the feed adjustment motor 57, and the vertical feed motor 66 are respectively provided with encoders 161, 571, 661 as detection means for detecting their shaft angles, and these encoders 161, 571, 661 are provided. Are connected to the microcomputer 91 via motor angle detection circuits 161a, 571a, and 661a.
Each encoder 161, 571, 661 outputs a pulse at a constant minute angular interval with respect to the output shaft of each motor 16, 57, 66, and each motor angle detection circuit 161a, 571a, 661a includes each encoder 161, 571. , 661 are counted. Then, the microcomputer 91 calculates the output shaft angle of each motor 16, 57, 66 from the count value.
The output shaft angle of the sewing machine motor 16 matches the upper shaft angle. The upper shaft angle is one rotation (0 to 360 °) and corresponds to one reciprocating vertical movement of the sewing needle. In the following description, the upper shaft angle 0 ° corresponds to the top dead center of the sewing needle, and 180 ° corresponds to the bottom dead center.

[Operation control of vertical feed motor]
Since the feed dog 31 needs to move up and down in synchronization with the up and down movement of the sewing needle, the motor control device 90 obtains the upper shaft angle from the output of the encoder 161 of the sewing machine motor 16, and the up and down feed motor 66 In order to synchronize with the sewing machine motor 16, operation control is performed so that the vertical feed motor 66 performs one reciprocal rotation between the swing angle of FIG. 5 and the swing angle of FIG. To do.
That is, the target swing angle of the vertical feed motor 66 is determined for each minute angle of the upper shaft angle, and based on the deviation between the current swing angle of the vertical feed motor 66 detected by the encoder 661 and the target swing angle. The vertical feed motor 66 is feedback-controlled.

By the way, as described above, the cloth presser 13 to which a predetermined pressing pressure is applied is disposed at the protruding and retracting position of the feed dog 31 on the upper surface of the needle plate 11. The vertical feed motor 66 that applies the vertical reciprocating motion to the feed dog 31 performs feedback control following the sewing machine motor 16 against the load caused by the pressing pressure from the cloth presser 13.
In order to perform the feedback control of the vertical feed motor 66 while ensuring the followability with respect to the sewing machine motor 16, as a control parameter, a position that is a deviation between the current swing angle of the vertical feed motor 66 and the target swing angle or a coefficient for the speed deviation. It is necessary to set a large gain and speed gain (hereinafter simply referred to as “gain”).
The memory 92 stores a first gain that is set to a numerical value that can perform a reciprocating rotation operation with appropriate followability with respect to the pressing pressure of the cloth presser 13. The pressing pressure of the cloth presser 13 can be adjusted and varies within a certain range, but the first gain is set to the most appropriate value for the entire range of the varying pressing pressure.
For this reason, when sewing is performed in a state in which the pressing pressure by the lowered cloth presser 13 is applied, the feedback control of the vertical feed motor 66 is performed based on the first gain, so that the sewing machine motor 16 can be satisfactorily followed. In addition, it is possible to send the sewing product appropriately.

On the other hand, when the adjustment work around the sewing needle of the sewing machine 100 is performed, the sewing machine motor may be driven in a state where the cloth presser 13 is retracted upward by the press-up lever.
In this case, since the feed dog 31 is not pressed by the cloth presser 13, the vertical feed motor 66 follows the sewing machine motor 16 in a state where there is no load by the cloth presser 13 and feedback control is performed.
However, if the feedback control of the vertical feed motor 66 is performed based on the first gain described above, the values of the position gain and the speed gain become too large, and the feed dog 31 has a large overshoot when it rises. There is a possibility that the base portion other than the tooth tip of the feed dog 31 may collide with the needle plate 11.
Accordingly, the memory 92 stores a second gain that is set to a numerical value that can perform a reciprocating rotation operation with appropriate follow-up performance when there is no pressing pressure of the cloth presser 13. The position gain and speed gain of the second gain are set to be smaller than the position gain and speed gain of the first gain described above.

FIG. 8 is a diagram showing an operation when the cloth presser 13 is lowered and the vertical feed motor 66 is driven. The “sewing machine rotation reference signal” in FIG. 8 is divided into a sewing needle lowering section (upper shaft angle 0 to 180 °) and a sewing needle raising section (upper shaft angle 180 to 360 °) output by the encoder 161 of the sewing machine motor 16. The “vertical feed motor shaft angle” is a signal indicating a change in the shaft angle of the output shaft output from the encoder 661 of the vertical feed motor 66.
The “control parameter switching signal” is a signal for the microcomputer 91 to instruct the motor driver 16a of the sewing machine motor 16 to switch between the first gain and the second gain.

  In the state of FIG. 8, since the cloth presser 13 is lowered, the first gain suitable for the load of the cloth presser 13 is maintained. Reference numeral L1 is a target shaft angle indicating the vertical feed motor shaft angle at the proper uppermost position of the feed dog 31 during sewing. The vertical feed motor shaft angle is equal to or less than the target shaft angle L1 from the initial rotation of the sewing machine motor 16. It can be seen that

FIG. 9 is a diagram showing an operation when the cloth presser 13 is retracted upward and the vertical feed motor 66 is driven.
Since there is no load due to the cloth presser 13, when the vertical feed motor 66 is driven with the first gain, the feed dog 31 is likely to overshoot when it is raised, and the vertical feed motor shaft angle is larger than the target shaft angle L1 described above. The high upper threshold L2 is exceeded.
The value of the upper limit threshold L2 is stored in the memory 92, and the microcomputer 91 monitors the “vertical feed motor shaft angle”, which is an output signal of the encoder 661 of the vertical feed motor 66, and the vertical feed indicated by this signal. When the motor shaft angle exceeds the upper limit threshold L2 (a value higher than the target shaft angle L1 described above), a switch from the first gain to the second gain is commanded by the control parameter switching signal.
That is, the encoder 661 of the vertical feed motor 66 functions as a “height detection unit that detects the height of the feed dog” according to the output shaft angle.
The upper limit threshold L2 is set to a vertical feed motor shaft angle at which the base portion other than the tip of the feed dog 31 does not collide with the lower surface of the needle plate 11.

The operation control of the vertical feed motor 66 by the motor control device 90 described above will be described based on the flowchart of FIG.
First, the microcomputer 91 of the motor control device 90 commands the start of driving of the sewing machine motor 16 and the vertical feed motor 66 and starts control of the vertical feed motor 66 (step S1).
At this time, the first gain is selected as a control parameter at the start of motor driving (step S3).

Next, the motor control device 90 detects the output of the encoder 661 of the vertical feed motor 66 and monitors the vertical feed motor shaft angle (step S5).
Then, it is determined whether the vertical feed motor shaft angle exceeds the above-described upper limit threshold L2 (step S7).
At this time, if the vertical feed motor shaft angle does not exceed the above-described upper limit threshold L2 (step S7: NO), it is determined whether the driving of the sewing machine motor 16 is stopped (step S9).
When the sewing machine motor 16 is stopped, the sewing is finished (step S9: YES), and when the driving of the sewing machine motor 16 is continued (step S9: NO), the process is returned to step S5.

On the other hand, in step S7, when the vertical feed motor shaft angle is equal to or greater than the above-described upper limit threshold L2 (step S7: YES), it is considered that the cloth presser 13 is retracted and there is no load due to the pressing pressure, and the microcomputer 91 Outputs a control parameter switching signal (step S11).
Thereby, the control parameter of the vertical feed motor is switched from the first gain to the second gain. Therefore, since the amount of movement of the vertical feed motor is reduced, overshoot of the feed dog 31 is suppressed, and the height of the feed dog 31 is reduced (step S13).

Next, the motor control device 90 determines whether or not the drive of the sewing machine motor 16 is stopped (step S15). If the drive of the sewing machine motor 16 is continued (step S15: NO), the process proceeds to step S11. Processing is returned.
If the sewing machine motor 16 is stopped, the sewing is finished (step S15: YES).

[Technical effects of the first embodiment]
In the sewing machine 100, the motor control device 90 stores the first gain and the second gain as control parameters relating to the response of the vertical feed motor 66, and the vertical feed motor shaft angle by the encoder 661 of the vertical feed motor 66. Accordingly, the motor is controlled by switching between the first gain and the second gain.
For this reason, even if the load of the vertical feed motor 66 varies due to the presence or absence of the pressing state of the cloth presser 13, the occurrence of overshoot of the feed dog 31 is suppressed, and the base portion other than the tooth tip of the feed dog 31 And the needle plate 11 can be prevented from colliding, and the feed dog 31 can be properly reciprocated up and down.

Further, the motor control device 90 stores an upper limit threshold L2 exceeding the target axis angle L1, and when the vertical feed motor shaft angle by the encoder 661 of the vertical feed motor 66 exceeds the upper limit threshold L2, the control parameter is set to the first parameter. The vertical feed motor 66 is controlled by switching from the gain to the second gain.
For this reason, when the vertical feed motor shaft angle exceeds the upper limit threshold L2, the overshoot suppression function of the feed dog 31 immediately works, and the occurrence of a collision between the base portion other than the tip of the feed dog 31 and the needle plate 11 is suppressed. In addition, it is possible to achieve proper optimization of the up and down reciprocating motion.

[Others]
In the first embodiment, the case where the motor control device 90 switches between the two control parameters of the first gain and the second gain according to the presence or absence of the pressing state of the cloth presser 13 is illustrated. The number is not limited to this.
For example, since the pressing pressure of the cloth presser 13 can be adjusted, the pressing pressure fluctuates within the adjustable range. Therefore, a gain composed of three or more values corresponding to the stepwise pressing pressure is prepared. Alternatively, three or more threshold values for the vertical feed motor shaft angle may be set stepwise to select a corresponding gain.

[Second Embodiment]
A second embodiment of the present invention will be described.
FIG. 11 is a block diagram of a sewing machine motor control device 90A according to the second embodiment.
The sewing machine according to the second embodiment includes a motor control device 90A obtained by adding a current detection unit 662A to the motor control device 90 of the sewing machine 100 described above. The machine configuration of the sewing machine is the same as that of the sewing machine 100.

The current detection unit 662A detects a current value supplied to the vertical feed motor 66 through the motor driver 66a.
The microcomputer 91 of the motor control device 90A can detect the fluctuation of the load applied to the vertical feed motor 66 by detecting the current value supplied to the vertical feed motor 66 by the current detector 662A. Thereby, it is possible to detect the presence or absence of the pressing state of the cloth presser 13 not from the output of the encoder 661 of the vertical feed motor 66 but from the current detection unit 662A.

In feedback control, when the deviation of the current supplied to the vertical feed motor 66 increases due to the load by the cloth presser 13 or the like, the current value is increased to increase the torque output and reduce the deviation.
For this reason, in a state where there is a load due to the pressing pressure with the cloth presser 13 descending, when the tooth tip of the feed dog 31 becomes higher than the upper surface of the needle plate 11, the detected current value by the current detecting unit 662A increases.
On the other hand, in the state where the cloth presser 13 is retracted and there is no load due to the pressing pressure, even when the tooth tip of the feed dog 31 is higher than the upper surface of the needle plate 11, the detected current value by the current detection unit 662A does not increase. .

Accordingly, the microcomputer 91 determines the current value to be supplied to the vertical feed motor 66 when the tooth tip of the feed dog 31 from the encoder 161 of the sewing machine motor 16 is higher than the upper surface of the needle plate 11. And compare with a predetermined current threshold. When the detected current value is larger than the threshold value, the first gain is selected assuming that there is a load due to the pressing pressure of the cloth presser 13, and when the detected current value is less than the threshold value, the presser of the cloth presser 13 is selected. The second gain is selected assuming that there is no load due to pressure, and the vertical feed motor 66 is controlled.
Note that the threshold value of the current is the current of the vertical feed motor 66 in a state where there is a load due to the pressing pressure of the cloth presser 13 in a certain section of the upper shaft angle where the tooth tip of the feed dog 31 is higher than the upper surface of the needle plate 11. It should be a value between the value and the current value of the vertical feed motor 66 in a state where there is no load due to the pressing pressure of the cloth presser 13 in the same section of the upper shaft angle.
The current threshold is also stored in the memory 92.

The operation control of the vertical feed motor 66 by the motor control device 90A will be described based on the flowchart of FIG.
First, the microcomputer 91 of the motor control device 90A commands to start driving the sewing machine motor 16 and the vertical feed motor 66, and starts control of the vertical feed motor 66 (step S21).
At this time, the first gain is selected as a control parameter at the start of motor driving (step S23).

Next, the motor control device 90A is a section where the current upper shaft angle is higher than the upper surface of the needle plate 11 from the output of the encoder 161 of the sewing machine motor 16 (referred to as a feed dog protruding section). It is determined whether or not there is (step S25).
If the current upper shaft angle is not the feed dog protruding section (step S25: NO), it is determined whether the drive of the sewing machine motor 16 is stopped (step S31).
When the sewing machine motor 16 is stopped, the sewing is finished (step S31: YES), and when the driving of the sewing motor 16 is continued (step S31: NO), the process is returned to step S25.

When the current upper shaft angle is the feed dog protruding section (step S25: YES), the motor control device 90A detects the energization current of the vertical feed motor 66 by the current detector 662A (step S27).
Then, it is determined whether the energization current value of the vertical feed motor 66 exceeds a prescribed threshold value (step S29).
At this time, when the energization current value of the vertical feed motor 66 is larger than the prescribed threshold value (step S29: NO), the drive stop determination of the sewing machine motor 16 described above is performed (step S31).
On the other hand, if the energization current value of the vertical feed motor 66 is equal to or less than the specified threshold value (step S29: YES), the microcomputer 91 considers that the cloth presser 13 is retracted and there is no load due to the pressing pressure, and the microcomputer 91 Is output (step S33).
Thereby, the control parameter of the vertical feed motor is switched from the first gain to the second gain. Therefore, the overshoot of the feed dog 31 is suppressed, and the height of the feed dog 31 is reduced (step S35).

Next, the motor control device 90A determines whether the drive of the sewing machine motor 16 has been stopped (step S37). If the drive of the sewing machine motor 16 is continued (step S37: NO), the process proceeds to step S33. Processing is returned.
If the sewing machine motor 16 is stopped, the sewing is finished (step S37: YES).

[Technical effects of the second embodiment]
In the sewing machine, the motor control device 90A controls the motor by switching between the first gain and the second gain according to the energization current value of the vertical feed motor 66.
For this reason, similarly to the case of the motor control device 90 described above, the occurrence of overshoot of the feed dog 31 is suppressed even when the load of the vertical feed motor 66 varies due to the presence or absence of the pressing state of the cloth presser 13. In addition, the occurrence of a collision between the base portion other than the tip of the feed dog 31 and the needle plate 11 can be reduced, and the vertical reciprocation of the feed dog 31 can be appropriately performed.

In addition, the motor control device 90A stores a current threshold value, and in the upper shaft angle section in which the feed dog 31 protrudes from the needle plate 11, the detected current value flowing through the vertical feed motor 66 by the current detection unit 662A is equal to or less than the threshold value. In this case, the vertical feed motor 66 is controlled by switching the control parameter from the first gain to the second gain.
In this case as well, as soon as the detected current value flowing through the vertical feed motor 66 falls below the threshold value, the overshoot suppression function of the feed dog 31 works, and the base plate other than the tip of the feed dog 31 collides with the needle plate 11. It is possible to realize the optimization of the reciprocating motion up and down quickly while suppressing the occurrence.

[Others]
In the second embodiment, the case where the motor control device 90A switches between the two control parameters of the first gain and the second gain according to the presence or absence of the pressing state of the cloth presser 13 is illustrated. It is not limited.
For example, since the pressing pressure of the cloth presser 13 can be adjusted, the pressing pressure varies within the adjustable range, and the energization current value of the vertical feed motor 66 in the feed dog protruding section also varies according to the pressing pressure.
Accordingly, a gain composed of three or more values corresponding to the level of the pressing pressure in steps is prepared, and three or more threshold values for the detected current value of the vertical feed motor 66 are set in steps, and the corresponding gains are set. May be selected.

  Further, in the case of a sewing machine provided with the motor control device 90A, when the sewing machine motor 16 is not driven and the sewing machine 16 is not being sewn, the current detection unit 662A detects the pressing pressure of the sewing product, and the current pressing pressure of the cloth presser 13 is detected. It is possible to determine which of the three or more types of stepping pressures belongs, and to select a gain as a control parameter suitable for this.

Specifically, the pressing pressure of the cloth presser 13 is arbitrarily adjusted with an adjusting screw to be in a lowered state.
Then, while the sewing machine motor 16 is stopped, the vertical feed motor 66 is driven to a specified projection height (for example, the maximum projection height at the time of sewing) in the feed dog projection section and stopped, and the vertical feed The energization of the vertical feed motor 66 is continued so that the output shaft of the motor 66 maintains the current position.
At this time, since the vertical feed motor 66 is energized so as to hold the current position with a torque output corresponding to the pressure of the cloth presser 13, the current detecting unit 662A corresponds to the current pressure of the cloth presser 13. A current value is detected.
Therefore, by storing a table indicating the relationship between the current value and the pressing pressure in the memory 92 of the motor control device 90A, the current pressing pressure of the cloth presser 13 is determined by the detected current value of the current detecting unit 662A. Can be identified.
Then, a gain as an appropriate control parameter is determined by selecting a corresponding one from a plurality of gains as a control parameter determined in a stepwise manner from the specified pressing pressure of the current fabric presser 13. be able to.
The process for determining the gain as the control parameter (referred to as “pressing pressure detection mode”) is performed, for example, by inputting the execution by the operation input unit 93 at the time of sewing.

FIG. 13 is a flowchart illustrating processing in the upper pressing pressure detection mode. Thus, the above processes will be described in order.
First, when execution of processing in the pressing pressure detection mode is input from the operation input unit 93, the motor control device 90A causes the vertical feed motor 66 and the feed dog top dead center at which the feed dog 31 has the highest protruding height during sewing. Control is performed so as to drive to the point and to stop and hold the position (step S41).

Then, the motor control device 90A detects the energization current value of the vertical feed motor 66 by the current detector 662A, and specifies the current pressing pressure of the cloth presser 13 (step S43).
Next, the motor control device 90A selects a corresponding one from a plurality of gains as control parameters determined in a stepwise manner from the specified pressure of the cloth presser 13, and determines the gain.

The motor control device 90A may be configured to individually perform the pressing pressure detection mode process and the control parameter selection process shown in the flowchart of FIG.
Further, in the processing of the upper presser pressure detection mode, there is a load caused not only by the presser pressure by the cloth presser 13 but also by the presser pressure of the cloth presser 13 based on the detected current value of the vertical feed motor 66 by the current detector 662A. It is also possible to determine whether or not there is no load, and when there is no load on the pressure of the cloth presser 13, a gain as a control parameter corresponding to this may be selected.

  90 A of motor control apparatuses can perform the process of the pressing pressure detection mode, and obtain the value of the pressing pressure by the cloth presser 13 (in addition, whether there is a load due to the pressing pressure or no load). Therefore, it is not necessary to drive the sewing machine motor 16 by one stitch, and it is possible to select a gain as an appropriate control parameter from the first stitch at the start of sewing.

In addition, although the sewing machine in 1st and 2nd embodiment mentioned above illustrated the structure which can adjust the pressing pressure of the cloth presser 13 manually with an adjustment screw, it is not limited to this.
For example, the pressing pressure can be increased or decreased in the vicinity of the numerical value input from the operation input unit 93, and the operation adjusting screw may be rotated by a motor so that the pressing pressure corresponding to the input value is obtained.
In this case, gains as a plurality of control parameters of the vertical feed motor 66 corresponding to various fluctuating pressing pressures are prepared in the memory 92, and gains corresponding to the pressing pressures input from the operation input unit 93 are prepared. It is desirable to select in advance.

11 Needle plate 13 Cloth presser 16 Sewing machine motor (drive source for reciprocating movement of feed direction component)
30 feed device 31 feed dog 40 horizontal feed mechanism 50 feed adjustment mechanism 60B vertical feed mechanism 66 vertical feed motor 66a motor driver 90, 90A motor control device 91 microcomputer 92 memory 93 operation input unit 100 sewing machine 161 encoder (height detection unit)
661 Encoder 662A Current detection unit

Claims (6)

In the sewing machine that combines the reciprocating motion of the feed direction component and the reciprocating motion of the vertical component to the feed dog that feeds the workpiece,
A motor serving as a drive source for the reciprocating operation of the feed direction component;
A vertical feed motor serving as a drive source for the reciprocating motion of the vertical component;
A cloth presser that holds the workpiece on the needle plate,
A height detector for detecting the height of the feed dog;
A motor control device that controls the vertical feed motor so that the feed dog feeds at a target height;
The motor control device stores a plurality of control parameters related to the responsiveness of the vertical feed motor, and switches the control parameter according to the detected height of the feed dog by the height detection unit to control the vertical feed motor. A sewing machine characterized by performing control.   The motor control device stores a threshold value that exceeds a target height of the feed dog, and switches the control parameter to change the upper and lower values when the detected height of the feed dog by the height detection unit exceeds the threshold value. The sewing machine according to claim 1, wherein the feed motor is controlled.   The sewing machine according to claim 1 or 2, wherein the height detection unit is an encoder that outputs a change in an axial angle of an output shaft of the vertical feed motor. In the sewing machine that combines the reciprocating motion of the feed direction component and the reciprocating motion of the vertical component to the feed dog that feeds the workpiece,
A motor serving as a drive source for the reciprocating operation of the feed direction component;
A vertical feed motor serving as a drive source for the reciprocating motion of the vertical component;
A cloth presser that holds the workpiece on the needle plate,
A height detector for detecting the height of the feed dog;
A current detection unit for detecting a current value flowing through the vertical feed motor;
A motor control device that controls the vertical feed motor so that the feed dog feeds at a target height;
The motor control device stores a plurality of control parameters related to the responsiveness of the vertical feed motor, and controls the vertical feed motor by switching the control parameter according to a current value flowing through the vertical feed motor. Characteristic sewing machine. The motor control device stores a threshold value of a current flowing through the vertical feed motor,
In the angular section of the upper shaft where the feed dog protrudes from the needle plate, when the detected current value flowing through the vertical feed motor by the current detection unit is less than or equal to the threshold value, the control parameter is switched to switch the vertical feed motor. The sewing machine according to claim 4, wherein control is performed.   The sewing machine according to claim 4 or 5, wherein the motor control device switches the control parameter in accordance with a current value flowing through the vertical feed motor during non-sewing.

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