JP2007212362A - Image processor and spring forming machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processor capable of stabilizing the measurement position in a coil spring, and a spring forming machine capable of improving the yield of the coil spring using the image processor. <P>SOLUTION: The spring length of the coil spring 91 and the feed amount of a wire rod 90 are metered on the condition that the tip cut end 92 of the wire rod 90 in the head part of the coil spring 91 lies between a first reference line L1 and a second reference line L2 and the displacement amount Zp between intersections becomes threshold Sk1 or more. Therefore, the rotation position of the coil spring 91 during measurement is stabilized, and more accurate measurement than before is allowed. Thus, variation in spring length and coil diameter of the coil spring is suppressed, and the yield can be improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus that captures an image of a coil spring being formed through a camera as needed and performs image processing, and a spring forming machine that corrects the position of a tool according to information acquired from the image processing apparatus.

Compared with a general coil spring, the length of the spring is relatively long, the pitch is relatively coarse, and the ratio of the coil diameter D to the wire diameter d (= D / d) is relatively large. Easy and yield is poor. On the other hand, there is known a spring forming apparatus that includes an optical spring length measuring device and stores a reference feeding amount of a wire and a reference spring length of a coil spring in correspondence with each other. In this spring forming machine, when the feed amount of the wire reaches the reference feed amount, the deviation amount between the reference spring length corresponding to the reference feed amount and the actually measured spring length is obtained, and according to the deviation amount. The position of the pitch tool was corrected (for example, see Patent Document 1).
JP-A-53-123363 (Claims 1 and 2, upper right column on page 4, lower left column on page 5, lines 2 to 10, line 2)

  By the way, when the feeding amount of the wire reaches the reference feeding amount while the coil spring is growing while rotating, the position of the tip end 1A of the wire 1 is the winding direction (see FIG. 18). 18 in the vertical direction). For this reason, in the conventional configuration, the difference between the reference spring length and the actually measured spring length is different between the reference spring length and the actually measured spring length under the condition that the position of the tip cut end 1A, that is, the number of turns is different. The amount of the pitch tool was to be corrected by obtaining the amount. For this reason, the correction is not performed accurately, and the shape of the coil spring varies, resulting in a poor yield.

  The present invention has been made in view of the above circumstances, and an image processing device capable of stabilizing the measurement position in the coil spring and a spring capable of improving the yield of the coil spring using the image processing device. The purpose is to provide a molding machine.

  In order to achieve the above object, an image processing apparatus according to the first aspect of the present invention provides an image of a coil spring which is formed from a wire rod by a spring molding machine and is inserted into the outside of a guide bar and growing while rotating. The first reference line and the second reference line that extend in the winding axis direction of the coil spring and are parallel to each other at a predetermined interval in the image processing apparatus that sequentially captures images from the side through the camera and performs image processing. The first of the images of the coil spring that is set to cross the side contour of the wire against the background of the guide bar and is located at the head of the coil spring at the intersection of the first reference line and the side contour of the wire Leading intersection detecting means for detecting a leading intersection and a second leading intersection located at the beginning of the coil spring among the intersections of the second reference line and the side contours of the wire, and the first leading intersection And the second intersection Interstitial point deviation amount detection means for detecting the deviation amount in the winding axis direction of the wire as an inter-intersection deviation amount, and the tip end of the wire rod is located between the first reference line and the second reference line, and the deviation amount between the intersection points And a measurable state detecting means for detecting a state in which the value becomes equal to or greater than a predetermined threshold as a measurable state.

  According to a second aspect of the present invention, there is provided a spring forming machine that includes a wire rod feeding device that feeds a wire rod, a pitch tool that can change a pitch of a coil spring, and a pitch that is set by a servo motor based on preset target position data. A control unit that controls the position of the tool, the image processing device according to claim 1, and a spring length measuring unit that measures the spring length of the coil spring on condition that the image processing device detects a measurable state; Further, the present invention is characterized in that it is provided with spring length correcting means for correcting the target position data so as to reduce a deviation amount between the actual spring length measured by the spring length measuring means and the theoretical spring length.

  According to a third aspect of the present invention, there is provided a spring forming machine that uses a wire feeding device that feeds a wire, a forming tool that can change a coil diameter of a coil spring, and a servo motor based on preset target position data. The control unit that controls the position of the forming tool, the image processing device according to claim 1, and the start of forming the coil spring, or that the image processing device has detected a measurable state, After the measurement of the wire feed amount is started, and after the wire has been fed for a predetermined number of turns, the measurement is terminated with the end condition that the image processing device has detected a measurable state. The feed deviation amount measuring means for obtaining a deviation amount between the actual feed amount measured until the end condition and the theoretical feed amount, and the actual feed amount obtained by the feed deviation amount measuring means The target position data is reduced so as to reduce the deviation from the theoretical feed amount. Characterized in place and a coil diameter correction means for correcting the data.

  A spring molding machine according to a fourth aspect of the present invention includes: a wire rod feeding device that feeds a wire rod; a molding tool that can change a coil diameter of a coil spring; a pitch tool that can change a pitch of the coil spring; A control unit that controls the positions of the forming tool and the pitch tool with a servo motor based on the target position data that has been set, the image processing apparatus according to claim 1, and a condition that the image processing apparatus has detected a measurable state The target position data is corrected so as to reduce the deviation between the spring length measuring means for measuring the spring length of the coil spring and the actual spring length measured by the spring length measuring means and the theoretical spring length. The measurement of the feed amount of the wire is started on the condition that the spring length correction means and the formation of the coil spring are started, or the image processing apparatus detects the measurable state, and then the predetermined number of turns Min wire is sent After that, the measurement is terminated with the end condition that the image processing device has detected a measurable state, and the actual feed amount and the theoretical feed amount measured between the start condition and the end condition are The feed deviation amount measuring means for obtaining the deviation amount of the feed and the coil for correcting the target position data so as to reduce the deviation amount between the actual feed amount and the theoretical feed amount obtained by the feed deviation amount measuring means. It is characterized in that it includes a diameter correcting means.

  According to a fifth aspect of the present invention, in the spring molding machine according to the second or fourth aspect, the spring length measuring means scans the laser beam along a scanning line offset laterally from the guide bar, and the laser projector. A laser receiver that receives the laser, and an arithmetic processing unit that detects the spring length of the coil spring based on the position where the laser light from the laser projector to the laser receiver is blocked by the head of the coil spring It is characterized in that it is provided with.

  A sixth aspect of the present invention is the spring molding machine according to the third or fourth aspect, wherein the control unit is configured to decelerate the wire feeding speed by the wire feeding device before the start condition or the end condition is satisfied. It has the characteristics in that place.

  The invention of claim 7 is the spring molding machine according to claim 3 or 4, wherein the theoretical wire feed amount fed from the start condition to the end condition is Lr, and from one turn of the coil spring When the predetermined reference feed amount set short is Sr, the control unit decelerates the wire feed speed at the reference position where the wire is fed with Lr-Sr as the target feed amount from the start condition, and the feed deviation The amount measuring means measures the actual feed amount from the reference position to the end position at which the image processing apparatus has detected the measurable state, and assuming that the actual feed amount is Sj, Sj−Sr is actually It is characterized in that it is determined so as to obtain the amount of deviation between the feed amount and the theoretical feed amount.

[Invention of Claim 1]
In the image processing apparatus according to the first aspect, the first reference line and the second reference line are set so as to cross the side outline of the wire rod with the guide bar as a background in the image of the coil spring. And among the intersections of the first reference line and the side contour of the wire rod, the first top intersection located at the top of the coil spring and the intersection of the second reference line and the side contour of the wire rod of the coil spring A deviation amount in the winding axis direction from the second top intersection point located at the head is detected as a deviation amount between the intersection points. Here, the silhouette of the leading portion of the coil spring against the background of the guide bar has a stepped shape with the leading end cut of the wire interposed therebetween, so the leading end cut of the wire is located between the first reference line and the second reference line. In such a case, the amount of deviation between the intersections is greater than in other cases and exceeds a predetermined threshold, and this state is detected as a measurable state. That is, according to the image processing apparatus of the present invention, only when the tip end of the coil spring is located at a certain rotational position around the guide bar in the process of the coil spring growing while rotating around the guide bar. Is detected as a measurable state. By measuring the spring length of the coil spring or the feeding amount of the wire rod on the condition that the image processing device has detected a measurable state, the measurement position in the coil spring becomes stable and more accurate measurement than before is possible. Is possible.

[Invention of claim 2]
In the spring forming machine according to claim 2, the spring length is measured and compared with the theoretical value on the condition that the image processing apparatus according to claim 1 detects the measurable state, and the target position data of the pitch tool is obtained. Therefore, more accurate correction than before can be performed, variation in spring length can be suppressed, and yield can be improved.

[Composition of claim 3]
In the configuration of claim 3, the feeding deviation amount measuring means is configured to start the coil spring, or the feeding deviation amount measuring means is based on the fact that the image processing apparatus according to claim 1 detects the measurable state. Measurement of the feed amount is started, and then the wire rod is fed for a predetermined number of turns, and the measurement of the feed amount of the wire rod is ended on the condition that the image processing apparatus has detected a measurable state. Here, the image processing apparatus according to claim 1 detects the measurable state only when the tip end of the coil spring is located at a certain rotational position around the guide bar. The variation in the number of windings actually formed can be suppressed. In addition, the wire feed amount L is as follows: the coil diameter is D, the pitch is P, the number of turns is N, and the wire length of the end turn part is a.
L = ((π · D) ² + P ² ) ^0.5 × N + a
Therefore, if the variation in the number of windings is small as described above, the variation in pitch or / and coil diameter is reflected in the amount of deviation between the theoretical value of the wire feed amount and the actual measurement value. Since the target position data of the forming tool is corrected so as to reduce the deviation amount of the coil diameter, variation in the coil diameter of the coil spring can be suppressed, and the yield can be improved as compared with the conventional technique.

[Invention of claim 4]
In the configuration of claim 4, the spring length is measured on condition that the forming of the coil spring is started or the image processing apparatus according to claim 1 detects the measurable state, and the measured value and Since the target position data of the pitch tool is corrected by comparing with the theoretical value, more accurate correction than before can be performed, and variations in the spring length can be suppressed. In addition, the image processing apparatus is formed between the start condition and the end condition, with the start condition being a measurable state and the image processing apparatus again detecting the measurable state is the end condition. Measure the amount of wire fed for a predetermined number of turns. And since the target position data of a forming tool is correct | amended by comparing the measured value and theoretical value of wire supply amount, the dispersion | variation in the coil diameter of a coil spring is suppressed conventionally. By these, a yield can be improved conventionally.

[Invention of claim 5]
According to the configuration of the fifth aspect, the spring length of the coil spring can be measured in a non-contact manner using a laser.

[Invention of claim 6]
According to the configuration of claim 6, since the wire rod feeding speed by the wire rod feeding device is decelerated before the start condition or the end condition is established, the tip end of the wire rod is formed between the first reference line and the second reference line. The rotational position of the coil spring when the image processing apparatus detects a measurable state is relatively stabilized. Thereby, measurement with higher accuracy can be performed.

[Invention of Claim 7]
In the configuration of claim 7, the wire is fed with Lr-Sr obtained by subtracting a predetermined reference feed amount Sr from the theoretical feed amount Lr of the wire fed from the start condition to the end condition as a target feed amount. The wire feeding speed is reduced at the fed reference position. Then, the amount of deviation between the actual feed amount and the theoretical feed amount from the reference position to the end position where the image processing apparatus detects the measurable state is obtained. Also with this configuration, it is possible to obtain a deviation amount between the theoretical wire feed amount fed from the start condition to the end condition and the actual wire feed amount.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment according to the invention will be described with reference to FIGS.
The spring forming machine 10 shown in FIG. 1 is assembled by assembling a wire feeder 20, a pair of up / down linear motion mechanisms 30, 30, a pair of inclined linear motion mechanisms 40, 40, etc. on a base 11 standing upright. Become. The wire rod feeding device 20 includes a pair of rollers 21 and 21 arranged on the front surface of the base 11 and arranged vertically. A wire guide 12 (generally called “quill”) is extended from one side (right side in FIG. 1) in the horizontal direction from the joint between the rollers 21 and 21 of the wire feeding device 20. A wire rod insertion hole (not shown) is formed through the wire rod guide 12 on a common tangent line between the rollers 21 and 21. Then, the wire 90 is sandwiched between the rollers 21 and 21, and the rollers 90 are rotated symmetrically by using the feeding servo motor 22 (see FIG. 5) as a drive source. Is fed from the tip of the wire guide 12. The wire 90 formed by the spring forming machine 10 of this embodiment has a circular cross section.

  As shown in FIG. 2, a mandrel tool 13 protrudes from the base 11 in front of the wire guide 12 in the wire feeding direction. The mandrel tool 13 has a bar shape with a semicircular cross section, and its flat side surface 13A faces the wire guide 12 side.

  As shown in FIG. 1, the pair of inclined linear motion mechanisms 40, 40 are attached to additional plates 41, 41 fixed to the front surface of the base 11. One inclined linear motion mechanism 40 extends obliquely upward from the mandrel tool 13 on the side opposite to the wire rod feeding device 20, and the other inclined linear motion mechanism 40 is disposed below the one inclined linear motion mechanism 40. Then, it extends so as to go obliquely upward as it moves away from the mandrel tool 13. Each inclined linear motion mechanism 40 is provided with a slider 43 that linearly moves in the direction in which they extend. One end of the link member 42 is rotatably connected to the end of the slider 43 on the side away from the mandrel tool 13, and the other end of the link member 42 is connected to the eccentric shaft 45 </ b> J of the rotating disk 45. It is connected so that it can rotate. The rotating disk 45 is pivotally supported with respect to the additional plate 41, and an eccentric shaft 45J is disposed at a position eccentric from the center of rotation. Then, the rotary disk 45 is rotationally driven by the vertical movement servomotor 46 attached to the back surface side of the additional plate 41, and thereby the slider 43 moves linearly.

  A tool attachment 43A is attached to the mandrel tool 13 side of the slider 43 of each inclined linear motion mechanism 40, and the forming tool 16 is fixed to the tool attachment 43A. As shown in FIG. 2, the forming tool 16 provided in one inclined linear motion mechanism 40 is abutted against the mandrel tool 13 obliquely from above, and the forming tool 16 provided in the other inclined linear motion mechanism 40 is It is abutted against the mandrel tool 13 obliquely from below. Further, round grooves (not shown) extend in the vertical direction on the front end surfaces of the forming tools 16 and 16. Then, the wire rod 90 fed from the wire rod feeding device 20 is guided upward in the round groove of each forming tool 16, 16, so that the wire rod 90 is formed in an arc shape so as to surround the mandrel tool 13. Thus, the coil spring 91 is formed, and the coil spring 91 grows away from the base 11 as shown in FIG.

  As shown in FIGS. 1 and 3, the vertical movement mechanisms 30 and 30 are symmetrically arranged vertically with the mandrel tool 13 interposed therebetween. Each vertical translation mechanism 30 includes a slider 31 similar to the slider 43 of the tilt translation mechanism 40, and the slider 31 is connected to an eccentric shaft 34 </ b> J of the rotating disk 34 via a link member 32. . Then, the rotary disk 34 is rotationally driven by the servo motor 35 so that the slider 31 moves directly.

  A tool mounting bracket 31A is fixed to the slider 31 in the upper vertical movement mechanism 30, and a cutting tool 15 is fixed to the tool mounting bracket 31A. The cutting tool 15 has a prismatic shape and extends vertically downward from the tool mounting bracket 31A. When the cutting tool 15 is lowered, it rubs adjacent to the flat side surface 13 </ b> A of the mandrel tool 13, and the wire 90 is cut between the edge of the cutting tool 15 and the edge of the mandrel tool 13.

  A tool mounting bracket 31A is fixed to the slider 31 in the lower vertical linear motion mechanism 30, and the pitch tool 14 is fixed to the tool mounting bracket 31A. As shown in FIG. 4, an inclined surface 14 </ b> A inclined with respect to the vertical direction is provided on the side opposite to the base 11 in the tip end portion of the pitch tool 14, and the inclined surface 14 </ b> A constitutes the coil spring 91. Is in contact with the base 11 in the winding axis direction. Then, by moving the pitch tool 14 upward, the wire 90 constituting the coil spring 91 can be pushed away from the base 11 to increase the pitch of the coil spring 91.

  As shown in FIG. 3 and FIG. 4, a guide bar 17 is provided on the coaxial extension line of the mandrel tool 13 and is abutted against the tip surface of the mandrel tool 13. The guide bar 17 has a circular cross section and is provided with a tapered portion 17A at the tip. Moreover, the base end part of the guide bar 17 is attached so that it can be attached or detached to the mount frame which is not shown in figure, and can move back and forth toward the metal core 13, for example. Then, the coil spring 91 grown away from the base 11 is inserted into the outside of the guide bar 17, and grows while rotating around the guide bar 17 (see FIG. 16).

  When the coil spring 91 is completed and separated from the subsequent wire 90 by the cutting tool 15, the guide bar 17 is retracted at a high speed, and the coil spring 91 is removed from the guide bar 17 and naturally falls.

  FIG. 5 shows a control device 60 for driving the spring molding machine 10. A control circuit 60C (corresponding to a “control unit” according to the present invention) of the control device 60 includes a CPU 61, a ROM 62, a RAM 63, and a flash memory 64. Then, by executing the NC program stored in the flash memory 64, the wire feeding device 20, the vertical linear motion mechanisms 30, 30, the inclined linear motion mechanisms 40, 40, etc. are driven, and the coil spring 91 is formed from the wire 90. Is done. FIG. 6 shows an example of a part of the NC program. As shown in the figure, in the NC program, designated tool numbers “Z1” to [Z3] and target position data D1 to D3 of the designated tool are written in parallel with “GO1” which is a tool movement command. Has been. Here, for example, “Z1” indicates one forming tool 16, “Z2” indicates the other forming tool 16, and “Z3” indicates the pitch tool 14. A correction arithmetic expression for subtracting the correction value H1 from the target position data D1 is written on the right side of the designated tool number “Z1”, and a correction is made from the target position data D2 on the right side of the designated tool number “Z2”. A correction arithmetic expression for subtracting the value H2 is described, and further, a correction arithmetic expression for subtracting the correction value H3 from the target position data D3 is described to the right of the designated tool number “Z3”. Then, the tools of the designated tool numbers “Z1” to “Z3” are positioned and controlled at the position specified by the numerical value of the calculation result of the correction calculation formula. That is, the target position data D1 to D3 can be corrected by subtraction of the correction values H1 to H3.

  The control circuit 60C corresponds to the “feeding deviation amount measuring means” according to the present invention, receives a detection value of a rotation sensor (not shown) provided in the feeding servo motor 22, and from the start of measurement to the end of measurement. The feed amount of the wire 90 is measured based on the difference between the detected values between the two, and the CPU 61 provided in the control circuit 60C executes step S45 of the coil diameter correction program PG4 described later, thereby obtaining the actual feed amount. Find the deviation from the theoretical feed amount.

  As shown in FIG. 1, the spring molding machine 10 is provided with a laser projector 53 and a laser receiver 54 with a guide bar 17 interposed therebetween, and the laser projector 53 and the laser receiver 54 are provided in the control device 60. The spring length measuring device 56 (corresponding to the “spring length measuring means” according to the present invention) is connected to the light projecting / receiving light control unit 55. In this spring length measuring device 56, the laser projector 53 scans the laser beam so as to cross the wire 90 of the coil spring 91 along a scanning line L3 offset laterally from the guide bar 17, as shown in FIG. Then, the laser light receiver 54 receives the laser light, and the light projecting / receiving control unit 55 detects the spring length of the coil spring 91 based on the position where the laser light is blocked by the coil spring 91.

  The spring molding machine 10 is provided with a camera 50 for image processing (specifically, a CCD camera). The camera 50 has an optical axis in a direction orthogonal to the axial direction of the guide bar 17, and is disposed obliquely above the guide bar 17. And the camera 50 image | photographs sequentially the coil spring 91 which grows along the guide bar 17, as shown in FIG. An annular illuminator 51 (see FIG. 1) is integrally fixed to the camera 50 with a bracket (not shown).

  An image photographed by the camera 50 is taken into an image processing device 52 provided in the control device 60. The image has a plurality of pixel data arranged in a matrix in the vertical and horizontal directions, and each pixel data has binary signal information composed of “white” and “black”. The shade of the shadow on the image is represented by the density of the pixel data “black” of the pixel data. Connected to the image processing device 52 is a monitor 52M for making the captured image visible. 7 and 8 conceptually show images captured by the image processing device 52. Here, since the coil spring 91 has a circular cross section, the degree of reflection of the light from the illuminator 51 on the camera 50 side toward the coil spring 91 differs depending on the position of the coil spring 91 in the circumferential direction. Then, the central portion in the width direction of the wire 90 as viewed from the camera 50 side becomes bright because the reflected light to the camera 50 is strong. Further, since the guide bar 17 is also circular in cross section, the reflected light to the camera 50 becomes weak and dark at both side portions of the guide bar 17 in the width direction. Further, since the coil spring 91 has a larger diameter than the guide bar 17, the white portion at the center of the coil spring 91 is projected on the black portion image on both sides of the guide bar 17. Thereby, the side part outline R1 of the wire 90 can be clearly distinguished against the background of the guide bar 17.

  The image processing device 52 executes the image processing program PG1 shown in FIG. 10 to perform image processing. Then, first, a reference line setting process (S11) is executed to set the first reference line L1 and the second reference line L2 on the captured image as shown in FIG. Specifically, for example, the center line in the width direction of the guide bar 17 is obtained from the contour lines (R3 in FIG. 7) on both sides in the width direction of the guide bar 17, and the center line is offset up and down. A first reference line L1 and a second reference line L2 are set. As a result, the first reference line L1 and the second reference line L2 extend in the winding axis direction of the coil spring 91 and cross the side outline R1 of the wire 90 with the guide bar 17 in the background.

  Next, a pixel data extraction process (S12 in FIG. 10) is executed to extract a pixel data group arranged along the first reference line L1 and the second reference line L2. Specifically, for example, a pixel data group arranged along the first reference line L1 with a width of 1 bit is taken, and a pixel data group arranged along the second reference line L2 with a width of 1 bit is taken. take in. FIG. 9 shows a part of a linear pixel data group having a 1-bit width arranged along the first reference line L1. In the figure, one of the square ridges corresponds to one pixel data G1.

  Next, the leading intersection specifying process (S13 in FIG. 10: corresponding to the “leading intersection detecting means” according to the present invention) is executed, and among the intersections between the first reference line L1 and the side contour line R1 of the wire 90 A first head intersection point P1 located at the head of the coil spring 91 is obtained, and a second head intersection point P2 located at the head of the coil spring 91 among the intersection points of the second reference line L2 and the side contour line R1 of the wire rod 90 is obtained. Ask. Specifically, a predetermined bit pattern is searched from the side away from the base 11 for a linear pixel data group having a 1-bit width arranged along the first reference line L1. As an example, for example, as shown in FIG. 9, the search is performed from the side away from the base 11 (the right side of FIG. 9), and the “black” pixel as in the part indicated by reference numeral A1 in FIG. When the bit pattern in which “white” pixel data continues for 3 bits or more is first recognized after the data continues for 3 bits or more, the position of the top pixel data G1 of the continuous “white” pixel data is Obtained as the first head intersection P1. The second head intersection point P2 is similarly determined.

  Next, an inter-intersection deviation amount calculation process (S14 in FIG. 10: corresponding to “inter-intersection deviation amount detection means” according to the present invention) is executed, and between the first leading intersection P1 and the second leading intersection P2. A deviation amount in the winding axis direction of the coil spring 91 is obtained as an inter-intersection deviation amount Zp. Specifically, the search start position of the predetermined bit pattern described above on the first reference line L1 and the second reference line L2 is set to the same position in the winding axis direction of the coil spring 91, and the search start position The difference between the bit length from the first start intersection point P1 to the first head intersection point P2 and the bit length from the search start position to the second start intersection point P2 is obtained as the above-described inter-intersection deviation amount Zp.

  Next, state detection processing (S15: corresponding to “measurable state detection means” according to the present invention) is executed to determine whether or not the amount of deviation Zp between the intersections is greater than or equal to a predetermined threshold value set in advance. Then, a case where it is equal to or greater than the threshold is detected as a measurable state, and a state detection signal Jk is output to the control circuit 60C.

  Here, as shown in FIG. 7, the silhouette of the leading portion of the coil spring 91 has a stepped shape with the leading end cut 92 of the wire 90 sandwiched therebetween, so that the leading end cut 92 of the wire becomes the first reference line L1 and the second reference line. When located between L2 (see FIG. 8), the inter-intersection deviation amount Zp is larger than in other cases (see FIG. 7). Therefore, the threshold value is always smaller than the inter-intersection deviation amount Zp when the front end cut 92 is located between the first reference line L1 and the second reference line L2 (see FIG. 8). It is always set to a value larger than the inter-intersection deviation amount Zp when it is not located between the line L1 and the second reference line L2 (see FIG. 7). If the inter-intersection deviation amount Zp is equal to or larger than the threshold value, the state detection signal Jk is output. If not, the state detection signal Jk is not output.

  In FIG. 14, for example, the graph Gf1 of the distance Y1 in the winding axis direction from the proximal end portion of the coil spring 91 to the first leading intersection P1 with respect to the feed amount X of the wire 90, and the coil spring 91 A graph Gf2 of the distance Y2 in the winding axis direction from the base end of the second head to the second head intersection P2 is shown. In the figure, the vertical axis interval of both graphs Gf1 and Gf2 widens at a constant interval, and the leading edge 92 of the wire rod 90 passes between the first reference line L1 and the second reference line L2 at this widening timing. Thus, it can be seen that the coil spring 91 rotates once.

  The control circuit 60C of the control device 60 measures the spring length Bj of the coil spring 91 and the feed amount Xj of the wire 90 on the condition that the state detection signal Jk is acquired from the image processing device 52. Specifically, every time the CPU 61 of the control circuit 60C forms the wire 90 one by one using the NC program described above, the counter update program PG2, the spring length correction program PG3, and the coil shown in FIGS. The diameter correction program PG4 is simultaneously executed by the multitask function.

  When the counter update program PG2 is executed, as shown in FIG. 11, the detection signal counter N is reset to the initial value “0” (S21), and thereafter the state detection signal Jk is acquired from the image processing device 52. (S22: YES), the detection signal counter N is incremented by one (S23). As a result, each time the coil spring 91 makes one rotation around the guide bar 17 and the leading edge 92 passes through a predetermined position (between the first reference line L1 and the second reference line L2), the detection signal counter. N is incremented.

  When the spring length correction program PG3 is executed, as shown in FIG. 12, the counter i is reset to the initial value “0”, and the spring length Bj (0) before molding is set to “0”. (S31). And it waits until the detection signal counter N becomes any value of “2”, “5”, “8” or “12” (S32: NO loop), and when it becomes any value (S32: YES), the counter i is incremented by 1 (S33), the spring length is measured by the spring length measuring device 56, and the measurement result is taken into Bj (i) (S34).

  Next, the spring length Bj (i-1) measured before that is subtracted from the spring length Bj (i), or in the case of the spring length Bj (1) measured first, the spring length Bj before molding The section spring length Bj is obtained by subtracting (0) (S35).

  Subsequently, the theoretical value Br (i) of the section spring length stored in advance in the data table is subtracted from the section spring length Bj to obtain a deviation amount ΔB between the actually measured value and the theoretical value (S36). Here, the theoretical value Br (i) of the section spring length can be obtained, for example, as the product of the number of turns included in a part of the section of the coil spring 91 and the designed pitch. Then, a value obtained by multiplying the deviation amount ΔB by a predetermined coefficient K3 is set as the correction value H3 in the NC program (S37), and the process returns to step S32. As a result, during the molding of one coil spring 91, the target position data of the pitch tool 14 is obtained at a total of four times when the detection signal counter N becomes “2”, “5”, “8”, or “12”. D3 is corrected.

  When the coil diameter correction program PG4 is executed, it waits until the detection signal counter N becomes “2” as shown in FIG. 13 (S41: NO loop), and the detection signal counter N becomes “2”. Using (S41: YES) as a start condition, measurement of the feeding amount Xj of the wire 90 is started by the wire feeding device 20 (S42). Then, the feeding amount is continuously measured until the detection signal counter N becomes “5” (S43: NO loop), and the end condition is that the detection signal counter N becomes “5” (S43: YES). The measurement of the feed amount Xj is finished (S44).

  Next, a theoretical feed amount Xr (i) of the wire 90 stored in advance in the data table is subtracted from the actually measured feed amount Xj to obtain a deviation amount ΔX (S45). Here, the theoretical feed amount Xr (i) is obtained by multiplying the function of the designed coil diameter and pitch by the number of turns “3” until the detection signal counter N changes from “2” to “5”. Can be sought. Then, a value obtained by multiplying the deviation amount ΔX by a predetermined coefficient K1 is set as the correction value H1 in the NC program, and a value obtained by multiplying the deviation amount ΔX by a predetermined coefficient K2 is set as the correction value H2 (S46). ), The coil diameter correction program PG4 is terminated. Thereby, the target position data D1 and D2 of the forming tools 16 and 16 are corrected at an initial stage during the formation of one coil spring 91.

The configuration of the spring forming machine 10 of the present embodiment is as described above.
The operation of the spring forming machine 10 will be described. The spring forming machine 10 repeats the operation of forming the coil spring 91 from the wire 90 and separating it from the subsequent wire 90 by repeatedly executing the NC program. At this time, each coil spring 91 is inserted outside the guide bar 17, grows while rotating around the guide bar 17, and the leading portion of the coil spring 91 moves in a direction away from the base 11. Then, the growing image of the coil spring 91 is sequentially captured from the side by the camera 50 at a predetermined cycle, and the captured images are sequentially captured by the image processing device 52.

  The image processing device 52 sequentially processes the captured images in a predetermined cycle as follows. That is, the first reference line L1 and the second reference line L2 are set so as to cross the side outline R1 of the wire rod 90 with the guide bar 17 in the background of the captured image (see FIG. 7). And the 1st top intersection P1 located in the head of the coil spring 91 among the intersections of the 1st reference line L1 and the side part outline R1 of wire 90, and the 2nd reference line L2 and side part outline R1 of wire 90 And the second head intersection point P2 located at the head of the coil spring 91 is identified, and the amount of deviation Zp between the intersection points in the winding axis direction between the first head intersection point P1 and the second head intersection point P2 is determined. Ask. Here, the silhouette of the leading portion of the coil spring 91 has a stepped shape with the leading end cut 92 of the wire 90 sandwiched therebetween, so that the leading end cut 92 has the first reference line L1 and the second reference line L2 as shown in FIG. 7, the inter-intersection deviation amount Zp becomes larger than that in the case where the front end cut 92 is displaced from between the first reference line L1 and the second reference line L2, as shown in FIG. Be over threshold. Then, the state in which the inter-intersection deviation amount Zp is equal to or greater than the threshold is detected as a measurable state, and a state detection signal Jk is output.

  Here, in this embodiment, as shown in the lowermost stage of FIG. 15, the entire coil spring 91 is wound by at least 12 turns. In other words, the coil spring 91 rotates about the guide bar 17 at least 12 times, and the leading edge 92 passes through the first reference line L1 at least 12 times, and the control circuit 60C of the spring forming machine 10 receives from the image processing device 52. The state detection signal Jk is received 12 times or more. Then, the CPU 61 of the control circuit 60C receives the predetermined state detection signal Jk from the start of forming the coil spring 91, and the spring of the coil spring 91 between the start and end of forming the coil spring 91. The length Bj is measured a plurality of times by the spring length measuring device 56. Then, since the section spring length for each section where the spring length Bj is measured is obtained and compared with the theoretical value, and the target position data D3 of the pitch tool 14 is corrected, the spring length variation of the formed coil spring 91 is varied. Is suppressed.

Further, the CPU 61 starts measuring the feed amount Xj of the wire 90 on the condition that the predetermined state detection signal Jk is received from the start of forming the coil spring 91, and then the wire for a predetermined number of turns. The measurement of the feed amount Xj is ended on the condition that the state detection signal Jk is received after 90 is fed. Here, the image processing device 52 outputs the state detection signal Jk only when the coil spring 91 is positioned at a certain rotational position around the guide bar 17 (that is, detects the measurable state), so the start condition Variation in the number of windings actually formed between the end condition and the end condition is suppressed. In addition, the wire feed amount L is as follows: the coil diameter is D, the pitch is P, the number of turns is N, and the wire length of the end turn part is a.
L = ((π · D) ² + P ² ) ^0.5 × N + a
Therefore, when the variation in the number of windings is small as described above, the variation in the coil diameter and the pitch is reflected in the deviation amount ΔX between the theoretical value and the actual measurement value of the feeding amount of the wire 90. Since the target position data D1 and D2 of the forming tools 16 and 16 are corrected so as to reduce the amount of deviation, variations in the coil diameter of the formed wire rod 90 can be suppressed.

  As described above, even if the shape of the wire 90 varies during molding, the cause of the variation can be quickly corrected by correcting the target position data D3 of the pitch tool 14 and / or the position data D1 and D2 of the molding tools 16 and 16. To be eliminated. The coil spring 91 is completed by cutting the coil spring 91 from the subsequent wire 90 after being wound by a predetermined number of times of 12 times or more.

  As described above, according to the spring molding machine 10 of the present embodiment, the front end cut end 92 of the wire 90 in the leading portion of the coil spring 91 is located between the first reference line L1 and the second reference line L2 and is shifted between the intersection points. Since the spring length of the coil spring 91 or the feed amount Xj of the wire 90 is measured on the condition that the amount Zp is equal to or greater than the threshold value, the rotational position of the coil spring 91 at the time of measurement is stable and more accurate than before. Measurement becomes possible. Thereby, the dispersion | variation in the shape of the coil spring 91 is suppressed, and a yield can be improved.

[Other Embodiments]
The present invention is not limited to the above-described embodiment. For example, the embodiments described below are also included in the technical scope of the present invention, and various other than the following can be made without departing from the scope of the invention. It can be changed and implemented.

  (1) In the above-described embodiment, it is preferable to decelerate the wire feeding speed by the wire feeding device 20 just before the start condition and the end condition for measuring the feed amount Xj are satisfied. As a result, the leading end 92 of the wire 90 enters relatively slowly between the first reference line L1 and the second reference line L2, and the rotational position of the coil spring 91 when the image processing device 52 detects the measurable state. Becomes more stable and more accurate measurement can be performed.

  (2) In the above embodiment, for the coil diameter correction, the CPU 61 of the control circuit 60C starts measuring the feeding amount Xj on the condition that the state detection signal Jk is acquired from the image processing device 52. The measurement of the feed amount Xj may be started on the condition that the molding of the coil spring 91 is newly started.

  (3) In the embodiment described above, the deviation amount ΔX between the theoretical feed amount Xr (i) of the wire rod 90 fed from the start condition to the end condition and the actual feed amount Xj is obtained, and the deviation amount. Although the coil diameter is corrected based on ΔX, it may be configured as follows. That is, the measurement of the feed amount Xj of the wire 90 is started on the condition that the forming of the coil spring 91 is started, and the feed amount Xj of the wire 90 is set to the end condition as shown in FIG. The wire rod 90 is fed at a normal feeding speed to a reference position Q1 which is theoretically short by a predetermined reference feed amount Sr than the length of the wire. Then, the wire rod 90 is fed at a low speed from the reference position Q1, and the actual position from the image processing device 52 to the end position where the image detection device 52 outputs the state detection signal Jk (the position where the leading edge 92 has reached the first reference line L1). Is measured, and a deviation amount ΔS (= Sj−Sr) between the actual feeding amount Sj and the theoretical feeding amount Sr is obtained, and the coil diameter is corrected based on the deviation amount ΔS. . Next, the passage of the end position is used as a start condition, and from there, as shown in FIG. 17B, the feed amount Xj of the wire 90 is theoretically a predetermined reference feed amount Sr from the length to reach the end condition. The wire 90 is fed at a normal feeding speed to the deficient reference position Q1, and the actual feeding amount Sj between the reference position Q1 and the wire 90 is fed at a low speed to the end position and the theoretical position. A deviation amount ΔS from the feeding amount Sr is obtained, and the coil diameter is corrected based on the deviation amount ΔS. This is repeated below.

  (4) In the embodiment, the spring length of the coil spring 91 is measured by the spring length measuring device 56, but the spring length may be measured by image processing.

  (5) The spring molding machine 10 of the above embodiment corrects all of the target position data D1 to D3 of the pitch tool 14 and the forming tools 16, 16, but corrects one or two target position data. You may make it the structure to carry out. Therefore, for example, a configuration in which only the spring length of the coil spring is measured or a configuration in which only the wire feed amount is measured may be used.

  (6) The theoretical values of the embodiment include not only values calculated from design numerical values but also empirical values obtained in the process of forming a good coil spring.

1 is a front view of a spring forming machine according to an embodiment of the present invention. Partial enlarged front view of a part of the spring forming machine Side view of spring forming machine Partially enlarged side view of a part of the spring forming machine Conceptual diagram showing the control configuration of the spring forming machine Program list showing part of NC program Conceptual image of guide bar and coil spring image Conceptual image of guide bar and coil spring image Conceptual diagram of pixel data group along the first reference line Flow chart of image processing program Counter update program flowchart Spring length correction program flowchart Coil diameter correction program flowchart A graph showing the positional relationship between the feed amount and the first and second intersections A graph showing the relationship between the feed amount and the position of each head intersection Graph showing the relationship between feed amount and spring length The partial expanded side view which expanded some spring forming machines of other embodiments Coil spring side view

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Spring forming machine 11 Base 14 Pitch tool 16 Forming tool 17 Guide bar 20 Wire rod feeding device 50 Camera 52 Image processing device 53 Laser projector 54 Laser receiver 56 Spring length measuring device (spring length measuring means)
60 control device 60C control circuit (control unit)
90 Wire material 91 Coil spring 92 End cut D1-D3 Target position data L1 1st reference line L2 2nd reference line L3 Scan line P1 1st top intersection P2 2nd top intersection R1 Side contour Zp Inter-point deviation amount ΔB, ΔX , ΔS Deviation amount

Claims (7)

In an image processing apparatus that performs image processing by sequentially capturing images of a coil spring that is molded from a wire rod by a spring molding machine and that is inserted into the outside of the guide bar and growing while rotating, from the side through a camera.
The first reference line and the second reference line that extend in the winding axis direction of the coil spring and are parallel to each other at a predetermined interval are the sides of the wire with the guide bar in the background of the image of the coil spring. Set to cross the contour line,
Of the intersections between the first reference line and the side contour of the wire rod, the first top intersection located at the top of the coil spring and the intersection of the second reference line and the side contour of the wire rod Head intersection detection means for detecting a second head intersection located at the head of the coil spring on the same image;
A point-to-intersection deviation amount detecting means for detecting the amount of deviation in the winding axis direction between the first head intersection point and the second head intersection point as a deviation amount between intersection points;
Detectable state detection in which a state where the tip end of the wire is located between the first reference line and the second reference line and the deviation amount between the intersections is equal to or greater than a predetermined threshold is detected as a measurable state. And an image processing apparatus. A wire feeding device for feeding the wire,
A pitch tool capable of changing the pitch of the coil spring;
A control unit for controlling the position of the pitch tool by a servo motor based on preset target position data;
An image processing apparatus according to claim 1;
A spring length measuring means for measuring a spring length of the coil spring on the condition that the image processing apparatus detects the measurable state;
Spring forming comprising spring length correcting means for correcting the target position data so as to reduce a deviation amount between an actual spring length measured by the spring length measuring means and a theoretical spring length. Machine. A wire feeding device for feeding the wire,
A forming tool capable of changing the coil diameter of the coil spring;
A control unit for controlling the position of the forming tool by a servo motor based on preset target position data;
An image processing apparatus according to claim 1;
The measurement of the feeding amount of the wire is started on the condition that the forming of the coil spring is started or the image processing apparatus detects the measurable state, and then a predetermined number of turns After the wire has been fed, the measurement is terminated on the condition that the image processing apparatus has detected the measurable state, and the actual feeding measured between the start condition and the end condition. A feeding deviation amount measuring means for obtaining a deviation amount between the quantity and the theoretical feeding amount;
Coil diameter correcting means for correcting the target position data so as to reduce the deviation amount between the actual feeding amount obtained by the feeding deviation amount measuring means and the theoretical feeding amount. Spring forming machine. A wire feeding device for feeding the wire,
A forming tool capable of changing the coil diameter of the coil spring;
A pitch tool capable of changing the pitch of the coil spring;
A control unit for controlling the positions of the forming tool and the pitch tool by a servo motor based on preset target position data;
An image processing apparatus according to claim 1;
A spring length measuring means for measuring a spring length of the coil spring on the condition that the image processing apparatus detects the measurable state;
Spring length correcting means for correcting the target position data so as to reduce a deviation amount between the actual spring length measured by the spring length measuring means and the theoretical spring length;
The measurement of the feeding amount of the wire is started on the condition that the forming of the coil spring is started or the image processing apparatus detects the measurable state, and then a predetermined number of turns After the wire has been fed, the measurement is terminated on the condition that the image processing apparatus has detected the measurable state, and the actual feeding measured between the start condition and the end condition. A feeding deviation amount measuring means for obtaining a deviation amount between the quantity and the theoretical feeding amount;
Coil diameter correcting means for correcting the target position data so as to reduce the deviation amount between the actual feeding amount obtained by the feeding deviation amount measuring means and the theoretical feeding amount. Spring forming machine.   The spring length measuring means includes a laser projector that scans a laser beam along a scanning line that is offset laterally from the guide bar, a laser receiver that is disposed opposite to the laser projector and receives the laser, and An arithmetic processing unit for detecting a spring length of the coil spring based on a position where a laser beam from the laser projector to the laser receiver is blocked by a head of the coil spring. The spring forming machine according to 2 or 4.   5. The spring molding according to claim 3, wherein the control unit is configured to decelerate a wire feeding speed by the wire feeding device before the start condition or the end condition is satisfied. Machine. When the theoretical feed amount of the wire fed from the start condition to the end condition is Lr, and a predetermined reference feed amount set shorter than one turn of the coil spring is Sr, The control unit decelerates the wire feeding speed at a reference position where the wire is fed using Lr-Sr as a target feeding amount from the start condition,
The feeding deviation amount measuring means measures an actual feeding amount from the reference position to an end position where the image processing apparatus detects the measurable state, and the actual feeding amount is defined as Sj. The spring forming machine according to claim 3 or 4, wherein Sj-Sr is obtained as a deviation amount between the actual feeding amount and the theoretical feeding amount.

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