JP2020012203A - Embroidery frame drive device of embroidery machine - Google Patents

Abstract

To provide an embroidery frame drive device of an embroidery machine which can perform positioning with higher accuracy and perform high speed and light driving without backlash.SOLUTION: An embroidery frame drive device 100 which drives an embroidery frame in a front, rear, left, and right directions of an embroidery machine includes: a first cam rack 204 which has a trochoidal tooth form and extends in a right and left direction of the embroidery machine; a first roller pinion 210 which is engaged with the first cam rack; a first motor 206 which rotationally drives the first roller pinion; a second cam rack 308 which has a trochoidal tooth form and extends in a longitudinal direction of the embroidery machine; a second roller pinion 306 which is engaged with the second cam rack; a second motor 304 which drives the second roller pinion; and a slider 202 which is movably provided in the longitudinal direction of the embroidery machine along the second cam rack. The first cam rack is movably mounted in the slider in a right and left direction with respect to the slider. A frame connection plate 10 for connecting the embroidery frame for supporting an object to be sewn is mounted in the first cam rack.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an embroidery frame driving device for an embroidery machine.

  In an embroidery machine or a sewing machine, various embroidery frame driving devices have been developed for driving a sewing frame or an embroidery frame for supporting an object to be sewn in the front-rear and left-right directions. A cogged belt is used for such an embroidery frame driving device. (Patent Document 1), a device using a rack gear and a pinion gear engaged with the rack gear (Patent Document 2), a device using a ball screw (Patent Document 3), and a device using a linear motor ( There is patent document 4).

JP 2001-000768 A JP 2008-173440 A JP 2005-065960 A JP-A-2004-024877

  A driving device using a cogged belt is capable of high-speed driving, but has a problem in that the cogged belt itself is an elastic body, so that the belt expands and contracts due to a load or heat and a positional shift occurs. In addition, since the cog belt and the toothed pulley engage with each other due to sliding contact, there is a problem that backlash occurs due to wear and causes displacement.

  In a drive device using a rack gear and a pinion gear, both the rack gear and the pinion gear are substantially rigid. There is a problem that noise is generated.

  A drive device using a ball screw is substantially rigid for both the ball nut and the screw shaft, so it is less likely to expand or contract due to load or heat, and is less likely to be misaligned. Although there is no problem, since the screw shaft is rotated and driven, the inertia of the screw shaft becomes a problem, and there is a problem that a high-output servomotor is required for high-speed driving.

  Further, in a drive device using a linear motor, the embroidery frame can be driven at high speed and with high accuracy by directly driving the embroidery frame, but there is a problem that it is very expensive. In addition, there is a model platform that is easily affected by the external environment such as a magnetic field, dust, and oil and is difficult to control. Furthermore, since a speed reduction mechanism cannot be incorporated, there is a problem that the drive device becomes large in order to obtain a large thrust.

  An object of the present invention is to provide an embroidery frame drive device for an embroidery machine that has no backlash, is capable of higher-precision positioning, and can be driven at high speed and lightly. And

According to the present invention, there is provided an embroidery frame driving apparatus for driving an embroidery frame in a front-rear and left-right direction of the embroidery machine with respect to a stationary portion of the embroidery machine. Cam rack extending in the first direction, a first roller pinion having a plurality of rotatable rollers engaged with the first cam rack, a first motor for driving the first roller pinion to rotate, and a trochoid tooth profile A second cam rack extending in the front-rear direction of the embroidery machine, a second roller pinion having a plurality of rotatable rollers engaged with the second cam rack, and a second roller driving the second roller pinion. Motor, and a slider provided movably in the front-rear direction of the embroidery machine along the second cam rack,
An embroidery frame driving device is provided in which a first cam rack is mounted on a slider so as to be movable in the left-right direction with respect to the slider, and an embroidery frame for supporting a workpiece is mounted on the first cam rack.

  According to the present invention, an embroidery frame driving device for driving the embroidery frame in the front-rear and left-right directions has first and second cam racks having trochoid tooth shapes, and first and second cam racks engaging with the first and second cam racks. Since the roller pinion is used, non-backlash, high-precision positioning and high-speed and light driving performance are possible.

1 is a perspective view of an embroidery frame driving device according to a preferred embodiment of the present invention. FIG. 2 is a perspective view of an X-axis drive unit of the embroidery frame drive device of FIG. 1. It is a perspective view of a roller pinion. It is a side view of the roller used for a roller pinion. It is a side view which shows another example of a roller. FIG. 5 is a schematic diagram illustrating a relative positional relationship between a roller of FIG. 4 and teeth of a cam rack. FIG. 6 is a schematic diagram showing a relative positional relationship between the rollers of FIG. 5 and teeth of a cam rack. It is a perspective view showing an example of a positioning mechanism of a roller pinion. 9 is a schematic diagram for explaining the operation of the positioning mechanism of FIG. 9 is a schematic diagram for explaining the operation of the positioning mechanism of FIG. FIG. 9 is a perspective view illustrating a positioning method in the positioning mechanism of FIG. 8 together with a Y slider. It is the perspective view seen from the opposite side to FIG. It is a perspective view which shows another example of the positioning mechanism of a roller pinion. FIG. 14 is a perspective view of the positioning mechanism of FIG. 13 shown with a Y slider. It is a perspective view showing an example of a backlash removal mechanism for removing backlash between a roller pinion and a cam rack. It is a perspective view showing other examples of a backlash removal mechanism. 4 is a schematic diagram for explaining a backlash formed between a roller of a roller pinion and teeth of a cam rack. It is a schematic diagram for explaining the operation of the backlash removal mechanism. It is a perspective view which shows another example of an embroidery frame drive device. It is a perspective view which shows another example of an embroidery frame drive device.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
Referring to FIGS. 1 and 2, an embroidery frame driving apparatus 100 according to a preferred embodiment of the present invention includes a frame 102 fixed to a stationary main body (not shown) of an embroidery machine (not shown), and an X-axis drive. And a Y-axis driving unit 300.

  The X-axis drive unit 200 has a Y slider 202 extending in the left-right direction or the X-axis direction of the embroidery machine. The Y slider 202 has a vertical wall 202a disposed vertically and a bottom wall 202b protruding horizontally from the lower end of the vertical wall 202a, and is viewed in a cross section (YZ plane) perpendicular to the X axis. It is a member that sometimes exhibits an approximately L shape. An X-axis servomotor 206 having an output shaft 206a (see FIGS. 9 and 10) is attached to the standing wall 202a as a first motor. The X-axis servo motor 206 is attached to the back surface of the upright wall 202a so that its output shaft 206a is horizontally oriented in the Y-axis direction and penetrates the upright wall 202a and projects from the opposite side surface. A roller pinion 210 is attached to the tip of the output shaft 206a as a first roller pinion. The X-axis servo motor 206 is also connected to a control device (not shown) of the embroidery machine such as an NC device, and is obviously controlled by a program.

  An X-axis guide 201 extending in the X-axis direction is fixed to the bottom wall 202b. A frame connecting plate 10 for mounting an embroidery frame (not shown) is attached to the bottom wall 202b so as to reciprocate along the X-axis guide 201. More specifically, a guide shoe (not shown) that slides along the X-axis guide 201 is attached to the bottom surface of the frame connecting plate 10 so that the frame connecting plate 10 can reciprocate in the X-axis direction. Is attached to the bottom wall 202b.

  A cam rack 204 extending in the X-axis direction is fixed to the frame connecting plate 10 as a first cam rack. The cam rack 204 has a trochoid tooth shape that engages with the roller pinion 210. The roller pinion 210 includes a pair of support plates 212 and 214 arranged in parallel, a plurality of rollers 218 extending between the support plates 212 and 214 in parallel with the central axis Op, and a pair of support plates 212 and 214. And a connecting portion 216 extending outward from one side along the central axis Op.

  The rollers 218 are arranged at equal intervals on a circumference around the central axis Op between the support plates 212 and 214. Rollers 218 are rotatably attached to support plates 212 and 214 at both ends. The distal end of the output shaft 206 a of the X-axis servo motor 206 is connected to the connecting portion 216. When the roller pinion 210 is attached to the X-axis servo motor 206, the center axis Op of the roller pinion 210 coincides with the center axis Om of the X-axis servo motor 206.

  The Y-axis drive unit 300 has a Y-axis servomotor 304 that reciprocates the X-axis drive unit 200 in the Y-axis direction as a second motor. The Y-axis servomotor 304 is attached to a bracket 302 fixed to the back surface of the vertical wall 202a of the Y slider 202. When the Y-axis servomotor 304 is mounted on the bracket 302, its output shaft (not shown) is oriented in the Z-axis direction. As a second roller pinion, a roller pinion 306 is attached to the tip of the output shaft of the Y-axis servo motor 304. The roller pinion 306 has substantially the same configuration as the roller pinion 210 of the X-axis drive unit 200. The Y-axis servomotor 304 is also connected to a control device (not shown) of the embroidery machine such as an NC device, and is obviously controlled by a program.

  A cam rack 308 extending in the Y-axis direction is fixed to the frame 102 as a second cam rack. The cam rack 308 has a trochoid tooth shape that engages with the roller pinion 306. A pair of Y-axis guides 318, 320 extending in the Y-axis direction are further fixed to the frame 102. Brackets 310 and 312 are attached to both ends of the Y slider 202, and guide shoes 314 and 316 that slide on Y-axis guides 318 and 320 are attached to the brackets 310 and 312. Thus, the Y slider 202 is attached to the frame 102 so as to be able to reciprocate in the Y-axis direction.

  By driving the Y-axis servo motor 304 in this way, the Y slider 202 is driven relative to the frame 102 in the Y-axis direction or in the front-rear and left-right directions according to the rotation direction of the output shaft. Similarly, by driving the X-axis servo motor 206, the frame connecting plate 10 is driven in the X-axis direction or the left-right direction with respect to the Y slider 202 according to the rotation direction of the output shaft 206a. Thus, the embroidery frame attached to the frame connecting plate 10 is driven in the front-rear and left-right directions with respect to the frame 102.

  In the present embodiment, the cam racks 204 and 308 having the trochoid tooth shape and the roller pinions 210 and 306 are used for the driving force transmission mechanism of the embroidery frame driving device 100 that drives the frame connecting plate 10 in the X-axis and Y-axis directions. Non-backlash, high-precision positioning and high-speed and light driving performance are possible. However, in order to obtain such an effect, the relative positioning between the cam racks 204 and 308 and the roller pinions 210 and 306, particularly the rollers 218 thereof, is important.

  Referring to FIGS. 3 to 7, the roller 218 of the roller pinion 210 is usually formed in a cylindrical shape as shown in FIG. In this case, as shown in FIG. 6, if the center axis Or of the roller 218 is inclined with respect to the axis Oc of the cam rack 204 (the direction parallel to the surface of the trochoid tooth profile of the cam rack 204) as shown in FIG. , The contact point Pc between the roller 218 and the tooth profile of the cam rack 204 is located near both ends of the roller 218. For this reason, noise is generated, a positioning error of the cam rack 204 in the X-axis direction is increased, or a smooth operation between the cam rack 204 and the roller pinion 210 is prevented.

  Therefore, for example, as shown in FIG. 5, it is possible to use a roller 218a in the form of a rotating body in which the central portion of the roller gradually expands outward in the radial direction along the central axis Or of the roller. In this manner, the roller 218a has at least a side surface obtained by rotating, for example, an ellipse, a quadratic curve, a hyperbola, or a curve having a larger radius at the center of the roller along the central axis Or around the central axis Or. Can be formed. As a result, even if an angular displacement occurs between the center axis Or and the axis Oc due to a mounting error, the contact point Pc between the roller 218 and the tooth profile of the cam rack 204 is located near the center of the roller 218. The aforementioned problems are reduced or prevented.

  In the above description, the roller pinion 210 and the cam rack 204 have been described, but the same applies to the roller pinion 306 and the cam rack 308.

  When positioning the roller pinion 210 with respect to the cam rack 204, positioning of the roller pinion 210 in the Z-axis direction may be a problem. If the roller pinion 210 is not sufficiently close to the cam rack 204 in the Z-axis direction, a gap or backlash as shown by reference numeral G in FIG. 17 is formed. Conversely, if the roller pinion 210 is urged or pressed against the cam rack 204 with a strong force, the roller pinion 210 and the cam rack 204 do not operate smoothly. In order to prevent this, a positioning mechanism for the roller pinion 210 described later can be provided.

  Referring to FIGS. 8 to 11, an example of a positioning mechanism of the roller pinion 210 is shown. In this example, the X-axis servo motor 206 is mounted on the vertical wall 202a of the Y slider 202 via the mounting plate 208. At the four corners of the mounting plate 208, slots 208a are formed. The mounting plate 208 is formed by inserting a fixing screw 220 into the slot 208a and screwing the fixing screw 220 into a screw hole (not shown) formed in the vertical wall 202a, or a through hole (not shown) formed in the vertical wall 202a. ), And screwed to a nut (not shown) from the opposite side to fix it to the standing wall 202a.

  The four slots 208a are arranged on a circumference centered on the center Os of the mounting plate 208, and are formed so as to be curved along the circumference. Thereby, the mounting plate 208 is guided by the slot 208a and the fixing screw 220, and can rotate around the center Os (see FIGS. 9 and 10). By rotating the mounting plate 208, the output shaft 206a of the X-axis servo motor 206 moves by a distance δ in the Z-axis direction.

  When the X-axis servomotor 206 is mounted on the vertical wall 202a of the Y slider 202, for example, as shown in FIGS. 11 and 12, a measuring device 222 having a function of a compression spring is used to mount the mounting plate 208 around the center Os. Can be determined. The measuring device 222 has a compression spring disposed therein, and can measure the force F acting on the measuring terminal 222a in the axial direction. The measured value is used to determine the force acting between the roller pinion 210 and the cam rack 204. An appropriate rotational position of the mounting plate 208 can be determined so that the pressure is constant.

  In the above description, the roller pinion 210 and the cam rack 204 have been described, but the same applies to the roller pinion 306 and the cam rack 308.

  Next, referring to FIGS. 13 and 14, another example of the positioning mechanism of the roller pinion 210 is shown. In this example, the roller pinion 210 is moved linearly in the Z-axis direction together with the X-axis servo motor 206 to perform positioning. 13 and 14, the X-axis servo motor 206 is mounted on a mounting plate 232 by mounting screws 238. The mounting plate 232 is mounted on the upright wall 202a of the Y slider 202 via a guide block 234 that holds the mounting plate 232 movably only in the Z-axis direction. The guide block 234 is attached to the upright wall 202a of the Y slider 202 by an attachment screw 236.

  A ball plunger 240 is provided on the top of the guide block 234. As is well known, the ball plunger 240 has a hollow body formed with external threads (not shown) that engage with internal threads (not shown) formed in the guide block 234, and is disposed within the body. And a ball or pin that is pressed in the axial direction of the ball plunger 240 by the pressing spring and partially protrudes from the tip of the main body of the ball plunger 240. The outer screw of the ball plunger 240 is screwed into the inner screw of the guide block 234, and the ball or pin of the ball plunger 240 is brought into contact with the top of the mounting plate 232 to urge the mounting plate 232 in the Z-axis direction. can do. Thus, the roller pinion 210 can be urged or pre-pressed to the cam rack 204 with a constant pressing force. Thus, even if the tooth surface of the cam rack is worn, the roller pinion 210 is constantly urged against the tooth surface of the cam rack 204 by the spring force of the ball plunger 240, and backlash is removed.

  In the above description, the roller pinion 210 and the cam rack 204 have been described, but the same applies to the roller pinion 306 and the cam rack 308.

  15 and 16, a backlash removing mechanism between the roller pinion 210 and the cam rack 204 is illustrated. In FIG. 15, the cam rack 204 includes a fixed cam rack 226 and a movable cam rack 224. The fixed cam rack 226 is fixed by a fixing screw 232 so as not to move with respect to the frame connecting plate 10. The movable cam rack 224 is movably attached to the fixed cam rack 226. The movable cam rack 224 has a slot 224a extending in the X-axis direction, and a mounting screw 228b is inserted into the slot 224a. The mounting screw 228b is screwed into an internal screw (not shown) formed in the fixed cam rack 226. Thus, the movable cam rack 224 is attached to the fixed cam rack 226 so as to be movable in the X-axis direction along the fixed cam rack 226.

  The cam rack 204 has a coil spring 232. As shown in FIG. 18, the movable cam rack 224 is urged in the X-axis direction by a coil spring 232 to remove backlash. Alternatively, as shown in FIG. 16, the movable cam rack 224 may be fixed by a fixing screw 230 at a position where the backlash is removed.

  In the above description, the roller pinion 210 and the cam rack 204 have been described, but the same applies to the roller pinion 306 and the cam rack 308.

  In the above-described embodiment, the Y-axis driving unit 300 drives the X-axis driving unit 200 on one side by one Y-axis servomotor 304. However, as shown in FIG. The device 330 may be further provided on the opposite side in the X-axis direction so that the X-axis driving unit 200 is driven in the Y-axis direction on both sides of the Y slider 202.

  The driving device 330 has a second Y-axis servomotor 304a that reciprocates the X-axis driving unit 200 in the Y-axis direction. The second Y-axis servo motor 304a is attached to a bracket 302a fixed to the back surface of the vertical wall 202a of the Y slider 202. When the second Y-axis servomotor 304a is mounted on the bracket 302a, its output shaft (not shown) is oriented in the Z-axis direction. A roller pinion 306a is attached to the tip of the output shaft of the second Y-axis servo motor 304a. The roller pinion 306a has substantially the same configuration as the roller pinion 210 of the X-axis drive unit 200. The second Y-axis servomotor 304a is also connected to a control device (not shown) of an embroidery machine such as an NC device, and is controlled in synchronization with the Y-axis servomotor 304 by a program. No. A cam rack 308a extending in the Y-axis direction is fixed to the frame 102. The cam rack 308a has a trochoid tooth shape that engages with the roller pinion 306a.

  Further, as shown in FIG. 20, the X-axis drive unit 200 may be driven in the Y-axis direction on both sides of the Y slider 202 by one Y-axis servo motor 304. In the Y-axis drive section 350 of FIG. 20, the output shaft (not shown) of the Y-axis servomotor 304 is coupled to an input section (not shown) of the gearbox 352. The gearbox 352 has an output shaft 354 extending in the X-axis direction, and roller pinions 356 and 368 are attached to both ends of the output shaft 354. Roller pinions 356, 358 engage cam racks 360, 362, respectively. The trochoid teeth are formed on the cam racks 360 and 362 on the upper side in the Z-axis direction.

DESCRIPTION OF SYMBOLS 10 Frame connection plate 100 Embroidery frame drive device 102 Frame 200 X-axis drive unit 201 Axis guide 202 Slider 202a Standing wall 202b Bottom wall 204 Cam rack 206 X-axis servomotor 206a Output shaft 208 Mounting plate 208a Slot 210 Roller pinion 212 Support plate 214 Support plate 216 Connecting portion 218 Roller 218a Roller 222 Measuring device 222a Measuring terminal 224 Movable cam rack 224a Slot 226 Fixed cam rack 232 Mounting plate 234 Guide block 240 Ball plunger 300 Y-axis driving portion 302 Bracket 302a Bracket 304 Y-axis servo motor 304a Second Y-axis Servo motor 306 Roller pinion 306a Roller pinion 308 Cam rack 308a Cam rack 310 Bracket 312 Packet 314 guide shoes 316 guide shoe 318 Y-axis guide 320 Y-axis guide 330 drives 350 the shaft driving unit 352 gearbox 354 output shaft 356 roller pinion 358 roller pinion 360 cam rack 362 cam rack 368 roller pinion

Claims (7)

An embroidery frame driving device that drives an embroidery frame in front, rear, left, and right directions of the embroidery machine with respect to a stationary portion of the embroidery machine,
A first cam rack having a trochoid tooth profile and extending in the left-right direction of the embroidery machine;
A first roller pinion having a plurality of rotatable rollers engaged with the first cam rack;
A first motor that rotationally drives a first roller pinion;
A second cam rack having a trochoid tooth profile and extending in the front-rear direction of the embroidery machine;
A second roller pinion having a plurality of rotatable rollers engaged with the second cam rack;
A second motor for driving a second roller pinion;
A slider provided movably in the front-rear direction of the embroidery machine along the second cam rack,
An embroidery frame driving device in which a first cam rack is attached to the slider so as to be movable in the left-right direction with respect to the slider, and an embroidery frame for supporting a workpiece is attached to the first cam rack.   2. The embroidery frame driving device according to claim 1, wherein the first and second roller pinions include rollers formed of a rotating body whose central portion bulges outward in the radial direction.   3. The embroidery frame driving device according to claim 1, further comprising a positioning device for positioning the first and second roller pinions relative to the first and second cam racks.   The positioning device changes the rotation position of the first and second roller pinions about an axis parallel to the rotation axis of each of the first and second roller pinions to thereby position the first and second roller racks with respect to the first and second cam racks. 4. The embroidery frame driving device according to claim 3, wherein the relative positions of the first and second roller pinions are changed.   The positioning device linearly moves the first and second roller pinions with respect to the first and second cam racks, so that each of the first and second roller pinions with respect to the first and second cam racks. 4. The embroidery frame driving device according to claim 3, wherein the relative position is changed.   3. The embroidery frame driving device according to claim 1, wherein the first and second cam racks include a fixed cam rack and a movable cam rack movably provided along the fixed cam rack.   3. The embroidery frame driving device according to claim 1, wherein both ends of the slider drive the slider in the front-rear direction.

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