JPS6047865B2 - sewing machine - Google Patents

Description

Detailed Description of the Invention 7 The present invention relates to a sewing machine, and particularly to a drive device for driving a swinging member that reciprocates around a fixed axis, such as a needle bar support and a feed adjuster. The present invention relates to a sewing machine having special features.

In conventional sewing machines, swinging members such as the needle bar support and the feed adjuster are driven by converting the rotation of the main shaft of the sewing machine into swinging motion by a motion conversion mechanism. This motion conversion mechanism generally requires many parts, which increases the cost of the device, and also has the disadvantage that it is difficult to manufacture a sewing machine compactly. Also, if you combine many parts,
It is inevitable that frictional resistance and play will occur between each part,
These causes a decrease in energy efficiency and a deterioration in the positioning accuracy of the swinging member, and furthermore, the high-speed response performance is limited by the inertia of each component. On the other hand, the motion conversion mechanism has been simplified or omitted by using a rotary step motor as a drive source for the swinging member, but in this case, a relatively large Since it is difficult to accommodate a step motor within the limited space of a sewing machine frame, the degree of freedom in design is severely restricted, and the transmission mechanism that transmits the driving force of the step motor to the swinging member is I needed some arrows.

Against this background, the present invention simplifies the mechanism of the sewing machine and improves energy efficiency by making the drive device for the various swinging members in the sewing machine capable of directly driving these swinging members. and 5 which were made for the purpose of improving sewing accuracy, enabling high-speed operation, and increasing the degree of freedom in design.

In order to achieve this objective, the sewing machine according to the present invention (
1) a needle bar to which a needle is fixed at the lower end; (2) a support 3 for the needle bar so that it can move up and down;
and (3) a needle bar support mounted on the sewing machine frame so as to be able to swing about one fixed axis in order to impart lateral swing movement to the needle; and (3) integral with the needle bar support. 4. It is configured to be swingable around the fixed axis and has a large number of teeth. A movable part is formed with a fixed part attached to the sewing machine frame, and a large number of teeth facing the large number of teeth of the movable part are formed, and a magnetic force is generated between the movable part and the fixed part. (4) a step drive device having an excitation coil wound around a fixed part to move the movable part in steps;
a drive command device for supplying a step drive command to the excitation coil to determine a lateral swing position of the needle with respect to a workpiece cloth to be sewn; The sewing machine is configured to perform a desired sewing operation on the work cloth.

In another aspect, (1) a feed dog for imparting a feed motion to the work cloth to be sewn; and (2) one fixed axis for controlling the feed motion of the work cloth by the feed dog. (3) a movable part formed integrally with the feed adjuster, capable of swinging around the fixed axis, and having a large number of teeth; A large number of teeth are formed facing the large number of teeth on the sewing machine frame, and a magnetic force is generated between the fixed part attached to the sewing machine frame, the movable part, and the fixed part to move the movable part in steps. (4) a drive command device for supplying a step drive command to the excitation coil in order to determine the adjustment position of the feed adjuster; The sewing machine is configured to perform a desired sewing operation on the work cloth by cooperating with a needle that reciprocates up and down according to the step operation of the step drive device.

The movable part and the fixed part can be made of laminated silicon steel plates, bulk electromagnetic mild steel, etc., and the movable part can also be made of a permanent magnet.

The surfaces of the movable part and the fixed part that face each other can be flat if the rotation angle of the swinging member is extremely small, but generally the center axis of rotation of the swinging member is It is desirable to have an arcuate curved surface centered on the center.

The fixed part and the movable part are attached to the sewing machine frame and the swinging member directly or indirectly through another member by various means such as adhesion, screw fixing, spring fixing, press fitting, etc.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a diagram showing only the characteristic parts of the sewing machine according to the present invention, and the sewing machine frame 1 is removed to clearly show the internal mechanism, and only the position is shown with two-dot chain lines.

Since the parts other than those shown here are the same as those of known sewing machines, the explanation will be omitted. A sewing machine frame 1 includes a bed 2 and a head 5 disposed above the bed supported by a support 3 and an arm 4.
It is equipped with A needle bar support 6, which is one of the swinging members, is provided inside the head 5, with a boss 7 formed at its upper end pivotally connected to a fixed frame (not shown) by a pivot 8. There is.

The needle bar support body 6 has needle bar support parts 9 and 11, one on top and one on the top.
These support the needle bar 12 so as to be swingable in the axial direction. A sewing machine needle 13 is attached to the lower end of the needle bar 12 by a needle holder 141. On the other hand, a needle bar holding shaft 16 is fixed to the intermediate portion of the needle bar 12 by a needle bar holding shaft 15, and this needle bar holding shaft 16 is connected to a needle bar crank rod 17.
It is connected to the needle bar crank 18 by. The needle bar crank 18 is connected to a sewing machine main shaft 19 which is disposed horizontally within the arm 4 and is rotated by a sewing machine motor (not shown).
Since the needle bar 12 is fixed to one end of the needle bar 12, the needle bar 12 is caused to reciprocate up and down as the main shaft 19 of the sewing machine rotates. To perform sewing work other than straight stitches, use the needle bar 12.
In addition to the above-mentioned vertical reciprocating motion, it is necessary to provide a lateral rocking motion to the motor, and this rocking motion is provided by a rocking type step drive device 20 (hereinafter simply referred to as a step motor). The swing width step motor 20 has a stator (fixed part) 21 fixed to the sewing machine frame 1 with a set screw (not shown), and a set screw 23 fixed to the needle bar support 11 at the lower end of the needle bar support 6. Swinger (movable part) 2
2. The stator 21 is made of laminated silicon steel plates, and as shown in enlarged form in FIGS. 2 and 3, four salient poles 2, I, ■, ■, and
4, each wire 25 is wound around each of these salient poles 24 to form an excitation coil, forming four stator phases.

Further, an appropriate number of stator teeth 26 are formed at the tip of each salient pole 24. On the other hand, the swinger 22 has a structure in which a permanent magnet 29 is sandwiched between laminated silicon steel plate parts 27 and 28 in which a large number of swinger teeth 30 are formed on the surface facing the stator 21, and the laminated silicon steel plate part 27 is the N pole. Thus, the laminated silicon steel plate portion 28 serves as the south pole.

The swinger teeth 30 on the north pole side and the swinger teeth 30 on the south pole side are shifted in phase by exactly 180 degrees. The stator teeth 26 and the swinger teeth 30 have their respective tip surfaces connected to the needle bar support 6.
They are formed so as to be located on an arcuate curved surface centered on the rotation center axis (the axis of the pivot 8), and are opposed to each other with a slight gap in between.

The maximum swing angle of the swinger 22 is 3 gears 12'', which corresponds to an oscillation width of ±5TmITL at the tip of the sewing machine needle 13. Stator teeth 26 and swinger teeth 3 are provided to position and hold the needle bar 12, needle bar support 6, and sewing machine needle 13.
0 is formed. Returning to FIG. 1, reference numeral 35 denotes a presser bar, which is always urged downward by a spring 36, but can also be held in the raised position by a known mechanism (not shown). A presser foot 38 is fixed to the lower end of the presser bar 35 by a thumbscrew 37. Presser foot 3
A needle plate (not shown) is provided on the bed 2 below the needle plate 8, and a feed dog 41 is arranged below the needle plate.

The feed dog 41 is screwed to a feed base 42, and when the feed base 42 is operated by a known feed drive mechanism (not shown), the feed dog 41 cooperates with the aforementioned presser foot 38 and throat plate. to give feed to the processed cloth. In the sewing machine of this embodiment, a feed adjuster 43 for adjusting the direction and amount of feed of the work cloth by the feed dog 41 is also driven by the step motor 50.

The feed adjuster 43 is provided with a guide groove 44 having a rectangular cross section on its end surface, and has a feed adjuster shaft 45 at one end that is supported by a bearing 47 of the bed 2 (see FIG. 4) and is arranged to rotate seven times. ,
It is fixed by a set screw 48. Feed adjuster 43
A feed angle top 46 is slidably fitted into the guide groove 44, and this feed angle top 46 is moved up and down within the guide groove 44 by a feed drive mechanism (not shown). Since the time guide groove 44 is not vertical but inclined, a horizontal motion component is generated in the feed angle piece 46, and this horizontal motion component is transmitted to the feed base 42 via the feed drive mechanism.
is transmitted to the feed dog 41, giving a feed motion to the feed dog 41. The magnitude of this feed movement, that is, the feed amount is determined by the guide groove 44.
The larger the inclination is, the larger the inclination is.If the direction of the inclination of the guide groove 44 is reversed, the feeding direction can be reversed.To do this, the feed adjuster 43 must be swung by a predetermined angle in both forward and reverse directions together with the feed adjuster shaft 45. This is why the feed step motor 50 is used as the drive mechanism. As shown in FIG. 4, the step motor 50 includes a stator 51 fixed to the sewing machine frame 1 with a set screw 53 and a swinger 52 fixed to the feed adjuster shaft 45 with a set screw 62. ing.

The stator 51 is a sintered product made by sintering pure iron and phosphorus powder.
Each salient pole 54 is provided with four salient poles 54, and each salient pole 54 is wound with one wire 55 many times to form an excitation coil, thereby configuring four stator phases. The winding direction of the wire 55 in the salient poles 54 of I and ■ is the same, and the salient poles 54 of ■ and ■
The winding direction of the wire 55 is also the same, but the salient poles 5 of I and ■
The winding directions of the wires 55 in the salient poles 54 of No. 4, ■ and ■ are different from each other. An appropriate number of stator teeth 57 are formed at the tip of each salient pole 54 along an arc centered on the axis of the feed regulator shaft 45, and a large number of swinger teeth 57 are formed on the opposite surface of the swinger 52. 58 is also the feed adjuster shaft 4
It is formed along an arc centered on the axis of 5. The swinger 52 is also a sintered product made of the same material as the stator 51, and includes a mounting arm 59.
It is fitted onto the feed adjuster shaft 45 and fixed with a set screw 62. The swinging angle range of the swinger 52 is 40, and the swinger teeth 58 and stator teeth 57 are formed so that the swinger 52 can be positioned and held at positions divided into three parts of this range.

The sewing machine constructed as described above is controlled by a control circuit shown in FIG.

The timing pulse generator 65 supplies one timing pulse to the CK (clock) terminal of the address counter 66 each time the sewing machine main shaft 19 reaches a specific rotational phase.

The address counter 66 is reset when the power-on signal SN is supplied to the RT (reset) terminal, counts the timing pulses supplied to the CK terminal, and stores the stitch information storage device 67 in accordance with each count. Configured to specify an address. At each address of the stitch information storage device 67, needle position (width) information and feed information for forming a predetermined stitch are stored.
Each time the designated address of the address counter 66 changes by one rotation, one set of needle position information and feed information is outputted to the step motor drive circuit 68. However, the needle position information and the feed information are output with a phase difference of approximately half a rotation of the sewing machine main shaft (19). Step motor drive circuit 68
is a swing drive circuit 69 in which the final stage transistors Tl, T2, T3 and T4 are connected to the wire 25 as shown in FIG. 6, and a final stage transistor T5.
includes a feeding drive circuit 71 connected to the aforementioned wire 55 as shown in FIG. That is, each wire 25 of the swinging step motor 20 is selectively energized in either the forward or reverse direction depending on whether the transistors T1 and T2 are made conductive or the transistors T3 and T4 are made conductive. , thereby stator teeth 26
The four stator phases including the salient poles 24 of I, ■, ■, and ■ are excited so that the salient poles of I, ■, ■, and ■ of the feed step motor 50 become N poles or S poles. The transistors T5 connected to the respective wires 55 are selectively made conductive and the respective wires 55 are energized, whereby the stator phases including the salient poles 54 of I and ■, respectively, are excited to the S pole, and The stator phases including each of the salient poles (2) are excited to the north pole. Next, the operation will be explained.

Each salient pole 2 of I, ■, ■, ■ of the swinging step motor 20
When the wires 25 of 4 are sequentially energized as shown in A, B, C, and D in Table 1, the step motor 20 is
It stabilizes in the states shown as C and D.

However, the upper half of FIG. 8 shows the north pole side of the swinger 22, and the lower half shows the south pole side in linear relation.For ease of drawing and understanding, the stator teeth are 26 and the number of swinger teeth 30 are under-drawn. When the current in direction 1 as shown in A in Table 1 is supplied to each wire 25 of the salient poles 24 of I, ■, ■, ■ in the stator 21, the stator teeth of the salient poles 24 of I, ■ The wires 25 are energized so that the stator teeth 26 of the salient poles 26 become the S poles, and the stator teeth 26 of the salient poles 24 of ■ and ■ become the N poles.

Therefore, on the N-pole side of the swinger 22 shown in the upper half of FIG. pole 2
The four stator teeth 26 push the swinger teeth 30 of the same polarity to the farthest position and are stabilized in the state shown at A in FIG. Also in the lower half of FIG. 8, the stator teeth 26 of the − salient poles 24 of ■,
, ■ The stator teeth 26 of the salient poles 24 are the swinger teeth 3 of the same polarity.
0 and is stable in the state shown at A in FIG. Next, if the wires 25 of the salient poles 24 of I, ■, ■, ■ are energized as shown in B in Table 1, the state stabilized as shown in B in Figure 8 for the same reason as above. , the swinger 22 is rotated to the left by an angle corresponding to 114 of the pitch of the swinger teeth 30 (swinger pitch).

Similarly, as shown in C and D in Table 1, I, ■, ■, ■
When the wire 25 of the salient pole 24 is energized), the swinger 22
are rotated and stabilized at the positions shown in C and D in FIG. 8, respectively, and when energized again as shown in A in Table 1, they are rotated by an angle corresponding to the swing pitch. Even when the energization state is changed from DC to BA in Table 1, the same explanation can be applied except that the direction of rotation of the swinger 22 is reversed.

That is, the wires 25 of the salient poles 24 of I, ■, ■, ■,
By sequentially giving step drive commands with the polarities shown in A, B, C, and D in Table 1, the swinger 22 can be moved in either the forward or reverse direction by an angle that is an integral multiple of the angle corresponding to 114 of the swinger pitch. This means that the needle bar support 6 can also be rotated by the same angle.

Therefore, based on the needle position information from the stitch information storage device 67, the transistors Tl, T2, T of the swinging width drive circuit 69
3 and T4 are appropriately connected and a step drive command is given to the wire 25, so that the vertical reciprocating movement of the needle bar 12 and the swinging movement of the needle bar 12 by the swing width step motor 20 are combined. , the movement of the sewing machine needle 13 necessary to form various pattern stitches is obtained.

It should be noted that in this embodiment, the swinging step motor 20 is a hybrid motor, as is clear from the above description.
Since it is M (permanent magnet) type, (1) large driving and holding torque can be obtained considering the size of the device, and (2) both attractive force and repulsive force can be generated between the stator 21 and the swinger 22. act, and as a result of these canceling each other out, the bearing load on the pivot shaft 8 of the needle bar support 6 is reduced, and the deflection of each part is reduced. A circuit for excitation voltage waveform shaping is not required in the drive circuit 68, and (4) the stator 21 and swinger 22
Since the gap between the swinger 22 and the swinger 22 can be increased, many advantages such as easier machining and assembly can be obtained, but it is of course also possible to use a variable reluctance type step motor that does not use a permanent magnet for the swinger 22. It is. Next, the operation of the feed regulator 43 will be explained with reference to Table 2 and FIG. 9.

FIG. 9 shows the feed step motor 50 in a linearly expanded manner, and the number of stator teeth 57 and swinger teeth 58 are less than the actual number in order to facilitate drawing and understanding. .

As shown in A in Table 2, the wire 55 of the I salient pole 54 and the wire 55 of the ■ salient pole 54 of the stator 51 are energized,
When the other wires are not energized, the ninth
As shown in A of the figure, the stator teeth 57 of the salient poles 54 of I are
The stator teeth 57 of the salient poles 54 are excited to the north pole, and each stator tooth 57 is excited to the swinger tooth 58.
The swinger 52 is held by attracting it to the nearest position.

If the energization state is changed from this state as shown in B in Table 2), the stator tooth 57 of the salient pole 54 of ■ becomes the N pole, and the stator tooth 57 of the salient pole 54 of Stator tooth 57
are respectively excited to the south pole and attract the swinger teeth 58 opposite them, so that the swinger 52 is rotated to the left by an angle corresponding to 1/4 of the swinger pitch and stabilized.

Similarly, if the wire 55 is energized as shown in C and D in Table 2, the swinger 52 rotates to the positions shown in C and D in FIG. When energized as shown in FIG. 2, the swinger 52 is rotated by an angle corresponding to the swinger pitch. Of course, when the energization state is changed to D-C-B-A in Table 2, the swinger 52 is moved to the right in FIG. For each step drive command given from the drive circuit 71, the swing pitch is rotated in either the forward or reverse direction by an angle corresponding to 1/4 of the swing pitch.

Therefore, each time the sewing machine main shaft 19 rotates once, a number of step drive commands corresponding to the feed information from the stitch information storage device 61 are applied to the feed drive circuit 71, so that the feed dog 41 receives the above-mentioned feed information. street. A feed motion in the direction and amount of is obtained, and this feed motion and the aforementioned sewing machine needle 1
In combination with the lateral rocking motion of step 3, a predetermined sewing operation is automatically performed.

In addition, as is clear from the explanation above, the feed step motor 50 is of the variable reluctance type with monofilar winding and unipolar excitation, but like the swinging width step motor 20, it may be of the hybrid PM type. is also possible.

Further, the swinging member is not limited to those of the above two embodiments, and for example, as known from Japanese Patent Publication No. 35-14086, the needle bar may be swinged around a vertical axis. By means of a needle bar support of the type that obtains a lateral oscillating movement of the sewing machine needle, or by a precessional movement of the needle bar, as is known from U.S. Pat. No. 3,782,311. Therefore, it is also possible to apply the present invention to a drive device for a needle bar support of a type that obtains a lateral oscillating movement of a sewing machine needle. Further, as is well known, the feed adjuster is provided with a guide groove for guiding a square piece operated by a forked rod that is engaged with a cam provided on the main shaft of the sewing machine and caused to swing. The present invention can also be applied to a drive device for a feed adjuster similar to No. 43, and in short, it is possible to apply the present invention to a sewing machine equipped with a member that swings around a fixed axis and needs to be positioned at multiple positions. If so, the present invention can be similarly applied. As described in detail above, the present invention is a member that swings around a fixed axis in a sewing machine, and which needs to be positioned at a plurality of seven positions, in a novel swing-type step drive device. Since the drive unit is designed to be driven by a rotary pulse motor, the drive unit itself is smaller than when a rotary pulse motor is used, increasing the degree of freedom in sewing machine design. Since there is no need for a complicated motion conversion mechanism such as a oscillating motion converter, frictional resistance, play and inertia can be significantly reduced, energy efficiency and sewing accuracy can be improved, and high-speed operation is possible. Many effects can be obtained, such as making it possible. Furthermore, by controlling the supply of current to the excitation coil of the step drive device, it is possible to control the position of the swinging member of the sewing machine in an open-loop manner, compared to the case where closed-loop servo control is used. The effect of reducing costs can be obtained. In addition, since the excitation coil of the step drive device is wound around the fixed part, the mass of the entire moving part can be reduced compared to when the coil is wound around the moving part, and the positioning of the swinging member is The effect of improving accuracy and responsiveness is obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts of a sewing machine which is an embodiment of the present invention. FIG. 2 is a front view of the swinging width step motor in the sewing machine of FIG. 1. FIG. 3 is a 3-3 sectional view in FIG. 2. FIG. 4 is a front view of the feed step motor in the sewing machine of FIG. 1. FIG. 5 is a block diagram of the control circuit of the sewing machine shown in FIG. 1. 6 and 7 are circuit diagrams of essential parts of the step motor drive circuit shown in FIG. 5. FIG. FIG. 8 is an explanatory diagram of the operation of the shaking step motor shown in FIG. 2. FIG. 9 is an explanatory diagram of the operation of the feed step motor shown in FIG. 4. 1 Sewing machine frame, 6: Needle bar support (swinging member), 8: Pivot, 20: Swing width step motor, 21: Stator (fixed part), 22: Swinger (
Movable part included 24: salient pole, 25: wire, 26: stator tooth, 30: swinger tooth, 43: feed adjuster swinging member, 45
: Feed adjuster shaft, 50: Feed step motor, 51:
Stator (fixed part), 52: Swinger (movable part).

Claims (1)

[Scope of Claims] 1. A needle bar to which a needle is fixed at the lower end, and one fixed axis for supporting the needle bar so that it can move vertically and reciprocally, and giving the needle a lateral rocking motion. A needle bar support body is installed on the sewing machine frame so as to be able to swing around the fixed axis, and a needle bar support body is integrally constructed with the needle bar support body so as to be able to swing around the fixed axis, and a large number of teeth are formed. A movable part is formed, and a large number of teeth facing the many teeth of the movable part are formed, and a magnetic force is generated between the fixed part attached to the sewing machine frame and the movable part and the fixed part. a step drive device having an excitation coil wound around a fixed part for moving the movable part in steps; and the excitation coil for determining the horizontal swing position of the needle with respect to the workpiece cloth to be sewn. a drive command device for supplying a step drive command to a sewing machine, the sewing machine performs a desired sewing operation on the work cloth according to the step operation of the step drive device. 2. A patent characterized in that the facing surfaces of the movable part and the fixed part are formed as arcuate curved surfaces centered on the fixed axis, and the movable part is fixed to the lower end of the needle bar support. A sewing machine according to claim 1. 3. A feed dog for applying a feed motion to the work cloth to be sewn, a feed adjuster that is swingable around one fixed axis to control the feed motion of the work cloth by the feed dog, and a movable part configured integrally with a feed adjuster, capable of swinging around the fixed axis, and having a large number of teeth formed therein;
A large number of teeth facing the large number of teeth of the movable part are formed,
A step having a fixed part attached to the sewing machine frame, and an excitation coil wrapped around the fixed part to generate a magnetic force between the movable part and the fixed part to move the movable part in steps. a drive device; and a drive command device for supplying a step drive command to the excitation coil in order to determine the adjustment position of the feed adjuster; A sewing machine that operates to perform a desired sewing operation on the processed cloth. 4. The sewing machine according to claim 3, wherein the opposing surfaces of the movable part and the fixed part are formed as arcuate curved surfaces centered on the fixed axis.