JP3000536B2 - Non-uniform pitch spring orientation detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the orientation of unequal pitch springs.

[0002]

2. Description of the Related Art An unequal-pitch spring (hereinafter referred to as a "spring") is one in which the pitch of coil windings in the direction of the center line of the coil is not uniform. In particular, as shown in FIG. Pitch is one end 1
b (the pitch between the centers of the windings 2 is n), and the other end 1a
Small (the pitch between winding centers is m). Such a spring 1 is employed, for example, as a measure against surging in a valve opening and closing mechanism of an automobile engine, and is mounted with the end 1a having a dense coil pitch on the head side and the sparse end 1b on the cam side.

In the assembly line of an automobile engine, the spring 1 is continuously supplied to a spring mounting device by a parts feeder in a predetermined orientation. In the parts feeder, a device for detecting the orientation of the spring and a device for reversing the one having the opposite orientation are incorporated.

As a device for detecting the orientation of a spring, a device using optical means is generally used.
And 6 are known. In the apparatus shown in FIG. 5, an identification mark 20 is manually applied to one end of the spring 1 at one end, either sparse or dense, for example, the spring winding 2 at the end 1a of the winding pitch m (dense) by paint or the like in advance. The identification mark 20 is automatically identified by image processing using the camera 21, and the direction of the spring 1 is detected. That is, from the image obtained by imaging the entire spring 1 with the camera 21,
It is determined which of the two ends of the spring 1 has the image of the identification mark 20 to determine whether the orientation of the spring 1 is correct. A method of confirming the orientation of the spring by visual judgment of an operator without using the camera 21 is also partially performed.

In the apparatus shown in FIG. 6, a lighting device 22 is disposed on one side of a spring 1 and a pair of light receiving elements 23 and 24 for receiving light passing through both ends of the spring 1 are disposed on the opposite side. The direction of the spring 1 is detected based on the difference in the amount of light passing through the lighting fixture 22 that has passed through both ends 1a and 1b. That is, the amount of light passing through the end 1a of the spring 1 with the small winding pitch m is equal to the end 1b of the large winding pitch n.
, The direction of the spring 1 is determined from the difference between the passing light amounts.

[0006]

The conventional spring orientation detecting device has the following problems.

(In the case of the apparatus shown in FIG. 5) (a) A work step and equipment for attaching an identification mark to one end of the spring are required, and the assembly cost of the spring is increased. (B) It is necessary to attach an identification mark to one end of a small pitch side or a large pitch side of a spring. If the identification mark is mistakenly attached to the opposite end, the orientation of the spring is erroneously determined. From lack of reliability. (C) When the spring is transported to the orientation detecting device by a parts feeder or the like, the identification mark attached to the spring is rubbed or stained, and it becomes difficult to identify the spring with the camera.
The orientation of the spring may be erroneously determined.

(In the case of the apparatus shown in FIG. 6) (a) Since the wire diameter, pitch, number of turns, etc. of the windings of the spring are different for each type, the amount of light passing through both ends which determines the orientation of the spring and the numerical condition of the difference are determined by the type. Different for each. Therefore, every time the type of the assembly spring is changed, complicated numerical condition setting for orientation determination is required, and the workability of the type switching is poor. (B) If the spring disposed between the luminaire and the light receiving element is displaced due to inclination or the like, the amount of light passing through both ends of the spring increases or decreases, and the orientation of the spring cannot be determined. There is a lack of reliability such as erroneous determination in some cases.

[0009]

According to the present invention, there is provided an illumination section for irradiating at least both ends of an unequal pitch spring with slit light parallel to the direction of the coil center line, and an illumination section illuminated with light from the illumination section. An imaging unit that captures and captures reflected light from linearly illuminated portions at both ends of an equal-pitch spring, and an image obtained by the imaging unit, from adjacent illuminated portions at both ends of an unequal-pitch spring. The mutual spacing,
A calculation determination unit that calculates the respective magnitude relations, and determines the direction of the unequal pitch spring from the comparison result;
The above problem is solved by an uneven pitch spring orientation detecting device comprising:

[0010]

The illuminated portions at both ends of the spring illuminated by the slit light of the illuminating portion are aligned on a straight line parallel to the center line direction of the spring, and the reflected light from the illuminated portion is applied to the spring winding in the imaging portion. A plurality of point-like images arranged in a straight line at an interval corresponding to the pitch of, the mutual interval between adjacent point-like images at both ends of the spring is calculated by the calculation determination unit, the magnitude relationship is compared, and from the comparison result The orientation of the spring is detected and determined. Since the orientation is detected by comparing the magnitudes of the winding pitches at both ends of the spring, accurate spring orientation detection can be performed without changing the numerical conditions even if the type of the spring is changed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a device for detecting the orientation of unequal pitch springs. The apparatus includes an illuminating unit 4 for irradiating a laser slit light 5 parallel to a center line of the spring 1 over the entire length of the spring 1 placed horizontally at a predetermined position;
An imaging unit 6 that captures the laser reflected light 5 ′ from the spring 1, and a calculation determination unit 10 that determines the magnitude of the winding pitch at both ends of the spring 1 from the image formed by the imaging unit 6 to detect the orientation. Prepare.

The illumination section 4 irradiates the spring 1 with laser slit light 5 from obliquely above. The irradiation position is determined by experimentally obtaining a range L in which reflected light can be reliably obtained even if the position of the spring 1 is shifted in the X direction and the Y direction in FIG. Set. Note that the displacement in the Y direction in FIG. 1B is dealt with by increasing the width S of the laser slit light. With the laser slit light 5, an illuminated portion 3 as shown in FIG. 2A is formed on the outer peripheral surface of the spring 1 over the entire length of the spring 1 in the center line direction. This illuminated part 3
Are point light sources arranged in a straight line at intervals corresponding to two pitches of the windings of the spring 1.

The image pickup section 6 includes a filter 7, a lens 8 and a camera 9, and is arranged at a position directly above the spring 1.
The filter 7 is an optical filter that transmits only the laser reflected light 5 ′ from the spring 1. The laser reflected light 5 ′ that has passed through the filter 7 passes through the lens 8 and passes through the camera 9.
Incident on. The camera 9 captures an image of the illuminated portion 3 of the spring 1 from the laser reflected light 5 ′, and outputs an image signal of a point-like image 11 as shown in FIG.

A filter 7 provided in the imaging section 6 cuts off disturbance light from the spring 1 other than the laser reflected light 5 '. Therefore, the image 11 obtained by the imaging unit 6 becomes only the point image 11 of the illuminated portion 3 of the spring 1, and the subsequent image processing is facilitated, and the accuracy of the image processing is increased.

The calculation judging section 10 judges the orientation of the spring 1 by performing arithmetic processing on the image signal from the image pickup section 6 as shown in the flowchart of FIG. Now, the first winding pitch from the outermost end of the end 1a on the smaller winding pitch side of the spring 1 is P1, the second winding pitch is P2, and the opposite end on the larger winding pitch side is P1. Assuming that the first winding pitch from the outermost end of 1b is P4 and the second winding pitch is P3, the operation determination unit 10 performs the following image processing. The winding pitches P1 to P4 are the pitches of the spring winding 2 in the illuminated portion 3 by the laser slit light 5.

When an image is input from the image pickup unit 6, the operation determination unit 10 firstly obtains a plurality of dot images 11 arranged in a straight line.
Labeling (numbering). Next, the barycentric coordinates of each labeled image 11 are calculated. That is, since the shape and area of the point-like image 11 are unstable, the coordinates of the center point of each image 11 are calculated by the centroid method, and the centroid coordinates 12 as shown in FIG. I do. The barycentric coordinates 12 correspond to the center point of each of the illuminated portions 3 of the spring winding 2 of the spring 1.

After that, the calculation judging unit 10 calculates the distance between the adjacent barycentric coordinates 12, calculates the winding pitch of the spring 1, and calculates the winding pitches P1 to P4 of the spring 1. This calculation is performed at least at both ends 1 of the spring 1.
This is performed including the two positions of the second winding pitches P2 and P3 of a and 1b. Then, the magnitudes of the second winding pitches P2 and P3 are compared, and the orientation of the spring 1 is determined from the comparison result. The second winding pitches P2 and P3 are extracted from both ends of the spring 1 because at both ends of the winding 2 of the spring 1, there are portions where the pitch is reduced due to the end of winding.

The magnitude comparison of the actually measured values of the second winding pitches P2 and P3 at both ends 1a and 1b of the spring 1 is performed without setting numerical conditions according to the type of the spring 1. Therefore, even if the type of the spring 1 is changed,
The device of the present invention can be used as it is.

[0020]

According to the present invention, the orientation of the spring is detected by calculating the winding pitch at both ends and comparing the size of the windings with the reflected light from the slit light applied to both ends of the unequal pitch spring. Compared with the method of detecting the orientation by the method of detecting the orientation by the difference in the amount of passing light at both ends of the spring, there is no risk of misjudgment due to the misalignment of the spring. Since the orientation is detected based on the magnitude relationship of the winding intervals, there is no need to change the setting of the detection conditions in accordance with the type change of the assembly spring, so that it is possible to easily and quickly respond to the change of the lot.

[Brief description of the drawings]

FIG. 1A is a front view showing an embodiment of the present invention,
(B) is a plan view.

FIGS. 2A and 2B are diagrams for explaining an image processing operation for spring orientation determination by the apparatus of FIG. 1, wherein FIG. 2A is a plan view of the spring, FIG. 2B is an image view of an illuminated portion of the spring, C) is an image diagram after image processing by the centroid method.

FIG. 3 is a flowchart showing an example of an image processing operation sequence for spring orientation determination by the apparatus of FIG. 1;

FIG. 4 is a side view showing an example of an unequal pitch spring.

FIG. 5 is a side view schematically showing a conventional spring orientation detecting device.

FIG. 6 is a side view schematically showing another conventional spring orientation detecting device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spring 2 Spring winding 3 Illuminated part 4 Illumination part 5 Laser slit light 5 'Laser reflected light 6 Imaging part 7 Filter 10 Operation determination part

Claims (1)

(57) [Claims] An apparatus for detecting the orientation of an unequal pitch spring in which the pitches of coil windings at both ends in the center line direction of the unequal pitch spring are different in size, wherein at least both ends of the unequal pitch spring are provided with coils. An illumination unit that irradiates slit light parallel to the center line direction; and an imaging unit that captures and captures reflected light from linearly illuminated portions at both ends of an unequal pitch spring irradiated with light from the illumination unit. And, from the image obtained by the imaging unit, calculate the mutual interval between adjacent illuminated portions at both ends of the unequal pitch spring, compare the magnitude relationship, and from the comparison result, the direction of the unequal pitch spring And a calculation judging unit for judging the orientation.