JP2016118550A - Shape measurement method and shape measurement device for coil spring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the shape of a coil spring in a short time with high precision.MEANS FOR SOLVING THE PROBLEM: A shape measurement method measures the shape of a coil spring. The surface shape of the strand wire of the coil spring is roughly measured while relatively linearly moving a non-contact displacement meter in an axial direction relative to the coil spring for each of a plurality of rotation angles when the non-contact displacement meter is relatively rotated with a first angle interval relative to the coil spring (S12). Next, the surface shape of the strand wire of the coil spring is measured by moving the non-contact displacement meter relative to the coil spring to the prediction position of the strand wire of the coil spring that can be predicted from measurement results of roughly measuring each of a plurality of rotation angles when the non-contact displacement meter is relatively rotated with a second angle interval smaller than the first angle interval relative to the coil spring (S14, S16).SELECTED DRAWING: Figure 4

Description

  The technique disclosed in this specification relates to a technique for measuring the shape of a coil spring. The coil spring here means a spring in which a strand is wound a plurality of times in the axial direction when viewed from the front.

  An apparatus for measuring the shape of a coil spring has been developed (for example, Patent Document 1). In the measurement apparatus of Patent Document 1, a coil spring is rotatably held around a winding axis, and a laser irradiation device (non-contact displacement meter) is disposed facing the coil spring. The laser irradiation device can linearly move in a direction parallel to the winding axis of the coil spring. In this measuring device, while rotating the coil spring at a predetermined feed angle, the surface shape of the spring is measured for each rotation angle while moving the laser irradiation device along the winding axis. Thereby, the overall shape of the coil spring is measured.

JP 2013-119088 A

  In the technique of Patent Document 1, the surface shape of the coil spring is measured by linearly moving the laser irradiation device in the axial direction of the coil spring for each rotation angle while rotating the coil spring around the axis. For this reason, in order to measure the entire shape of the coil spring, it is necessary to repeat the rotation around the axis of the coil spring and the movement of the laser irradiation apparatus in the axial direction. If the feed angle of the coil spring is set to be small, the measurement accuracy is improved, but there is a problem that it takes time for measurement. On the other hand, if the feed angle of the coil spring is set to be large, the measurement time can be shortened but the measurement accuracy is lowered.

  This specification aims at providing the technique which makes it possible to measure the shape of a coil spring accurately in a short time.

  This specification discloses the shape measuring method which measures the shape of a coil spring. This measurement method includes an arrangement step, a first measurement step, and a second measurement step. In the arranging step, the coil spring is arranged so that both ends of the coil spring are located on a preset axis. The first measurement step is non-contact with the coil spring for each of a plurality of rotation angles when the non-contact displacement meter is rotated relative to the coil spring at a first angular interval around the axis. The surface shape of the wire of the coil spring is measured while moving the linear displacement meter relatively linearly in a direction parallel to the axis. The second measurement step is for each of a plurality of rotation angles when the non-contact displacement meter is rotated relative to the coil spring at a second angular interval smaller than the first angular interval around the axis. The surface shape of the coil spring wire is measured by moving the non-contact displacement meter to the coil spring to the predicted position of the coil spring wire predicted from the measurement result of the first measurement step.

  In this shape measuring method, measurement is performed when rotated at the second angular interval using the measurement result when rotated at the first angular interval. That is, the position of the strand is predicted from the measurement result when rotated at the first angular interval, and the surface shape of the coil spring strand is measured by moving the non-contact displacement meter to the predicted position. . For this reason, in a 2nd measurement process, the range which must measure the surface shape of the strand of a coil spring can be narrowed. As a result, measurement can be performed in a short time even if the second angular interval is set small. In this shape measuring method, the shape of the coil spring can be measured with high accuracy in a short time.

  Moreover, this specification discloses the measuring apparatus which can implement suitably said shape measuring method. That is, the measuring device disclosed in this specification includes a holding jig that holds the coil spring so that both ends of the coil spring are located on a predetermined axis, and a surface shape of the coil spring held by the holding jig. A non-contact displacement meter capable of measuring the angle, and an adjustment mechanism for adjusting the position of the non-contact displacement meter with respect to the coil spring held by the holding jig. In this measuring apparatus, an adjustment mechanism is used to adjust the rotation angle of the non-contact displacement meter relative to the coil spring with respect to each of the plurality of rotation angles when rotated relatively to the coil spring at a first angular interval. While the non-contact displacement meter is relatively linearly moved in a direction parallel to the axis, the surface shape of the wire of the coil spring is measured by the non-contact displacement meter. For each of the plurality of rotation angles when the non-contact displacement meter is rotated relative to the coil spring at a second angular interval smaller than the first angular interval around the axis, The non-contact displacement meter is moved relative to the coil spring by the adjustment mechanism to the predicted position of the coil spring wire predicted from the measurement result of the surface shape of the wire, and the coil spring element is moved by the non-contact displacement meter. Measure the surface shape of the line.

The figure which shows the structure of a shape measuring apparatus typically. The figure for demonstrating operation | movement of the laser displacement meter at the time of shape measurement. The figure which predicted the relationship between the position of the strand of a coil spring, and the position of the circumferential direction. The flowchart which shows the flow of a shape measurement by a shape measuring apparatus. The flowchart which shows the flow of a rough measurement process. The flowchart which shows the flow of a detailed measurement process. The flowchart which shows the flow of a strand detection process. The figure which shows the structure of the shape measuring apparatus of Example 2 typically. The graph which shows a visual field when the shape of a coil spring is measured using a pattern projection type sensor. The graph which shows a visual field when measuring the shape of a coil spring using a laser displacement meter. The figure which shows the structure of the shape measuring apparatus of Example 3 typically.

  Hereinafter, some technical features of the embodiments disclosed in this specification will be described. The items described below have technical usefulness independently.

(Feature 1) In the measurement technique disclosed in this specification, in the second measurement step, the position of the non-contact displacement meter in the radial direction of the coil spring is based on the coil diameter predicted from the measurement result of the first measurement step. By adjusting the distance, the distance between the coil spring and the non-contact displacement meter may be adjusted. According to such a configuration, even when the diameter of the coil spring changes in the axial direction of the coil spring, the distance between the non-contact displacement meter and the coil spring is adjusted to an appropriate distance. The surface shape of the line can be measured.

(Feature 2) In the measurement technique disclosed in this specification, in the second measurement step, the non-contact displacement meter may move so that the predicted position is located at the center of the visual field of the non-contact displacement meter. According to such a configuration, since the wire of the coil spring is easily located at the center of the field of view of the non-contact displacement meter, the surface shape of the wire of the coil spring can be accurately measured.

(Feature 3) In the measurement technique disclosed in the present specification, in the first measurement step, a first step of rotating a non-contact displacement meter relative to the coil spring relative to the coil spring by a first angle; The second step of measuring the surface shape of the element wire of the coil spring while moving the non-contact displacement meter relatively linearly relative to the coil spring in a direction parallel to the axis may be repeatedly performed. According to such a configuration, the surface shape of the wire of the coil spring can be efficiently measured at the first angular interval in the circumferential direction of the coil spring.

(Feature 4) In the measurement technique disclosed in the present specification, in the second measurement step, the non-contact displacement meter moves linearly relative to the coil spring along the axial direction of the coil spring, and at the same time, the shaft A non-contact displacement meter may move to the predicted position by rotating around the coil spring. According to such a configuration, the time for measuring the surface shape of the coil spring can be shortened by moving the non-contact displacement meter spirally with respect to the coil spring.

  The shape measuring apparatus 10 of an Example is demonstrated referring drawings. The shape measuring device 10 is a device that measures the shape of the coil spring W. As shown in FIG. 1, the shape measuring apparatus 10 includes a holding jig 12, 14, a drive mechanism (16, 18) that drives the holding jig 12, 14, a laser displacement meter 24, and a laser displacement meter 24. An adjustment device (20, 22, 26-30) for adjusting the position and angle and an arithmetic device 32 are provided.

  The holding jigs 12 and 14 hold the coil spring W to be measured. The holding jig 12 has a conical shape and holds one end of the coil spring W. The holding jig 14 has a conical shape and holds the other end of the coil spring W. The holding jigs 12 and 14 are arranged so that their respective axes are coaxial, and are arranged so that the apexes of the conical shape face each other. The holding jigs 12 and 14 can rotate around the axis thereof (around the axis parallel to the Z axis) while holding the coil spring W. In the following description, the rotation axis of the holding jigs 12 and 14 may be simply referred to as a rotation axis.

  The drive mechanism (16, 18) is controlled by the arithmetic unit 32 to switch between a state (holding state) where the coil spring W is held by the holding jigs 12, 14 and a state where the coil spring W is not held (non-holding state). The coil spring W held by the tools 12 and 14 is rotated around the rotation axis of the holding jigs 12 and 14. Specifically, the drive mechanism (16, 18) includes a rotating mechanism 16 and a reciprocating mechanism 18. The rotation mechanism 16 includes a motor and a transmission mechanism that transmits the rotation operation of the motor to the holding jig 12. When the rotation mechanism 16 operates, the holding jig 12 rotates around its axis. In a state where the coil spring W is held by the holding jigs 12 and 14, the rotation of the holding jig 12 is transmitted to the holding jig 14 by the coil spring W. As a result, the holding jigs 12 and 14 and the coil spring W are rotated together around the axis. The rotation angle of the motor is detected by an encoder. The arithmetic device 32 can position the holding jig 12 at a predetermined angle based on the rotation angle detected by the encoder (the rotation angle of the holding jig 12).

  The reciprocating mechanism 18 includes a motor and a conversion mechanism that converts the rotating operation of the motor into a reciprocating operation of the holding jig 14. When the reciprocating mechanism 18 is actuated, the holding jig 14 is separated from the holding jig 12 in the axial direction (Z-axis direction) and close to the holding jig 12 in the axial direction (Z-axis direction). The state is switched to When the holding jig 14 moves in a direction approaching the holding jig 12 with the coil spring W disposed between the holding jigs 12 and 14, the coil spring W is clamped (held) by the holding jigs 12 and 14. The Conversely, when the holding jig 14 moves in a direction away from the holding jig 12, the coil spring W held by the holding jigs 12, 14 can be removed from the holding jigs 12, 14.

  The laser displacement meter 24 is a kind of non-contact displacement meter, which irradiates the measurement object (that is, the coil spring W) with laser light and receives light reflected from the measurement object, thereby measuring the measurement object. Measure the surface shape. The laser displacement meter 24 inputs the measurement result to the arithmetic device 32. The laser displacement meter 24 is a two-dimensional laser displacement meter having a line light source, and irradiates the measurement object with slit light. The slit light emitted from the laser displacement meter 24 has the rotation axis of the holding jigs 12 and 14 positioned on the optical axis thereof, and extends along the rotation axis of the holding jigs 12 and 14. A part of W in the axial direction is irradiated. As will be described later, the laser displacement meter 24 is movable in the Z-axis direction. By moving the laser displacement meter 24 in the Z-axis direction, the entire axial direction of the coil spring W is irradiated with laser light. On / off of the laser displacement meter 24 is controlled by the arithmetic unit 32. As the laser displacement meter 24, a known laser displacement meter can be used.

  The adjusting devices (20, 22, 26 to 30) are controlled by the arithmetic device 32 and adjust the position and laser irradiation direction of the laser displacement meter 24 with respect to the coil spring W held by the holding jigs 12 and 14. . Specifically, the adjustment device (20, 22, 26-30) includes a z-direction position adjustment device (22, 28) for adjusting the position of the laser displacement meter 24 in the Z-axis direction, and an r-axis of the laser displacement meter 24. An r-direction position adjusting device (20, 30) for adjusting the position of the direction and an irradiation angle adjusting device 26 for adjusting the irradiation direction of the laser light emitted from the laser displacement meter 24 are provided.

  The z-direction position adjusting device (22, 28) includes a z-direction guide rail 22 and a z-direction position adjusting mechanism 28. The z-direction guide rail 22 guides the laser displacement meter 24. The z-direction guide rail 22 extends parallel to the rotation axis of the holding jigs 12 and 14 (that is, the Z-axis direction). The z-direction position adjusting mechanism 28 moves the laser displacement meter 24 along the z-direction guide rail 22. The z-direction position adjusting mechanism 28 includes a motor and a conversion mechanism that converts the rotation of the motor into the movement of the laser displacement meter 24 in the z direction. The rotation angle of the motor is detected by an encoder. The computing device 32 can position the laser displacement meter 24 at a predetermined position in the z-axis direction based on the rotation angle (drive amount of the z-direction position adjusting mechanism 28) detected by the encoder.

  The r direction position adjusting device (20, 30) includes an r direction guide rail 20 and an r direction position adjusting mechanism 30. The r-direction guide rail 20 engages with the z-direction guide rail 22 and guides the z-direction guide rail 22. The r-direction guide rail 20 extends in a direction orthogonal to the z-direction guide rail 22 and in a direction approaching or separating from the coil spring W held by the holding jigs 12 and 14. The r-direction position adjusting mechanism 30 moves the z-direction guide rail 22 along the r-direction guide rail 20. The r-direction position adjusting mechanism 30 includes a motor and a conversion mechanism that converts the rotation of the motor into a displacement in the r direction of the z-direction guide rail 22. As the z-direction guide rail 22 moves along the r-direction guide rail 20, the laser displacement meter 24 moves in the r direction. That is, the laser displacement meter 24 is movable in a direction approaching or separating from the coil spring W held by the holding jigs 12 and 14. The rotation angle of the motor of the r-direction position adjusting mechanism 30 is detected by an encoder. The computing device 32 can position the laser displacement meter 24 at a predetermined position in the r-axis direction based on the rotation angle detected by the encoder (the driving amount of the r-direction position adjusting mechanism 30).

  The irradiation angle adjusting device 26 adjusts the mounting angle of the laser displacement meter 24 with respect to the z-direction guide rail 22. That is, the laser displacement meter 24 is attached to a slider (not shown) guided by the z-direction guide rail 22. The slider is provided with an attachment shaft, and a laser displacement meter 24 is rotatably attached to the attachment shaft. The mounting shaft for attaching the laser displacement meter 24 is orthogonal to both the z-direction guide rail 22 and the r-direction guide rail 20. The irradiation angle adjusting device 26 adjusts the irradiation direction of the laser light emitted from the laser displacement meter 24 by rotating the laser displacement meter 24 around the mounting axis. Since the mounting axis is orthogonal to the Z direction and the r direction, the laser displacement meter 24 rotates in the rz plane. As the laser displacement meter 24 rotates, the laser light emitted from the laser displacement meter 24 is emitted from a direction that obliquely intersects the rotation axis of the holding jigs 12 and 14. Therefore, the laser beam can be irradiated from the front (direction perpendicular to the axis) to the coil spring W held by the holding jigs 12 and 14, and obliquely upward or obliquely downward (direction intersecting the axis obliquely). Can be irradiated with laser light.

  The arithmetic device 32 controls the operation of the drive mechanism (16, 18), the laser displacement meter 24, and the adjustment device (20, 22, 26-30), and changes the shape of the coil spring W from the measurement result of the laser displacement meter 24. calculate. In other words, the arithmetic device 32 controls the operation of the drive mechanism (16, 18) and the adjustment device (20, 22, 26-30), so that the laser light emitted from the laser displacement meter 24 can be detected by the coil spring W. It can be determined whether the part is illuminated. For this reason, the arithmetic unit 32 first stores the operation states of the drive mechanisms (16, 18) and the adjustment devices (20, 22, 26-30) and the measurement results output from the laser displacement meter 24 in association with each other. Then, the shape of the coil spring W is calculated from the stored information. Specifically, the arithmetic unit 32 specifies the shape of the coil spring W by processing the stored position information and measurement information according to the processing program. The shape of the coil spring W specified by the arithmetic device 32 is displayed on a display (not shown). Note that a known computer can be used as the arithmetic device 32.

  Next, the flow of measuring the shape of the coil spring W using the shape measuring apparatus 10 described above will be described. The shape measuring apparatus 10 calculates the shape of the coil spring W by performing each process shown in FIG. First, in step S <b> 10 of FIG. 4, the coil spring W is set in the shape measuring apparatus 10. That is, the arithmetic unit 32 drives the reciprocating mechanism 18 to move the holding jig 14 to a position away from the holding jig 12 so that the coil spring W can be set on the holding jigs 12 and 14. To do. When one end of the coil spring W is set on the holding jig 12, the arithmetic device 32 drives the reciprocating mechanism 18 to move the holding jig 14 in a direction close to the holding jig 12. As a result, the coil spring W is held by the holding jigs 12 and 14.

  If it progresses to step S12 of FIG. 4, the shape measuring apparatus 10 will implement the rough measurement process which measures the approximate shape of the coil spring W. FIG. In the rough measurement process, the shape measuring apparatus 10 measures the approximate shape of the coil spring W, and creates a movement locus of the laser displacement meter 24 when performing detailed measurement from the measured approximate shape of the coil spring W. The rough measurement process will be described with reference to FIG.

(Coarse measurement process)
As shown in FIG. 5, in the rough measurement process, first, the arithmetic device 32 drives the rotating mechanism 16 and the adjusting devices (20, 22, 26 to 30) to adjust the position of the laser displacement meter 24 and the laser irradiation angle. However, the surface shape of the coil spring W is measured by the laser displacement meter 24 (step S20). This will be specifically described with reference to FIG. First, the arithmetic device 32 drives the rotation mechanism 16 to position the holding jigs 12 and 14 and the coil spring W at a predetermined rotation angle θ (rotation angle θ around the rotation axis of the holding jigs 12 and 14). Further, the arithmetic device 32 drives the z-direction position adjustment mechanism 28 and the r-direction position adjustment mechanism 30 to position the laser displacement meter 24 at the initial position. Further, the arithmetic device 32 drives the irradiation angle adjusting device 26 so that the laser light emitted from the laser displacement meter 24 becomes an angle orthogonal to the rotation axis of the holding jigs 12 and 14. Thereby, the laser displacement meter 24 is set to an initial state. When the laser displacement meter 24 is in the initial state (the state shown in FIG. 2A), the laser displacement meter 24 is positioned at a position outside the holding jig 12 in the Z direction (a position below in FIG. 2) (that is, a lower position). The laser displacement meter 24 is set at a predetermined distance from the rotation axis of the holding jigs 12 and 14.

  Next, the computing device 32 measures the surface shape of the coil spring W with the laser displacement meter 24 while driving the z-direction position adjusting mechanism 28 to move the laser displacement meter 24 in the z direction. This measurement is performed until the laser displacement meter 24 moves to a position outside the holding jig 14 in the Z direction (position indicated by B in FIG. 2). Thereby, the surface shape (position of the strand) of the coil spring W at the position of the predetermined rotation angle in the circumferential direction of the rotating shaft is measured over the entire axial direction of the coil spring W. The surface shape measured by the laser displacement meter 24 is stored in the arithmetic device 32. The laser displacement meter 24 moves from a position A (a position below the holding jig 12) to a position B (a position above the holding jig 14) shown in FIG. The measured results include the results of measuring the surface shapes of the holding jigs 12 and 14.

  Hereinafter, the holding jigs 12 and 14 and the coil spring W are positioned to a predetermined rotation angle θ by driving the rotating mechanism 16 and the measurement by the laser displacement meter 24 while driving the z-direction position adjusting mechanism 28 is performed. Run repeatedly. Thereby, the surface shape of the coil spring W at a plurality of rotation angles in the circumferential direction of the rotating shaft is measured, and the measurement result is stored in the arithmetic unit 32. In the rough measurement, for example, the surface shapes at four locations in the circumferential direction of the coil spring W are measured. In this case, the holding jigs 12 and 14 and the coil spring W are rotated by the rotation mechanism 16 at intervals of 90 °. In the rough measurement process, the rough shape of the coil spring W is measured in a short time by setting the angular interval wide.

  When proceeding to step S22 of FIG. 5, the arithmetic unit 32 analyzes the measurement result obtained in step S20 and detects the positions of the holding jigs 12 and. As described above, the measurement result obtained in step S20 includes the shape of the coil spring W and the shapes of the holding jigs 12 and 14. It is known in advance that the holding jigs 12 and 14 have a conical shape and the side surfaces thereof are measured as straight lines. For this reason, the arithmetic unit 32 specifies the positions of the holding jigs 12 and 14 from the measurement result obtained in step S20 using the shape information of the holding jigs 12 and 14 given in advance.

  Next, the computing device 32 detects the shape of the spring wire of the coil spring W (step S24). That is, the coil spring W to be measured in this embodiment is formed by coiling a spring steel wire having a circular cross section. In step S24, the shape of the coil spring W is extracted from the measurement result of step S20, and the shape of the spring wire is specified from the extracted measurement result. The process of step S24 will be described with reference to FIG.

  As shown in FIG. 7, in the strand detection process, first, data obtained by measuring the shape of the holding jigs 12 and 14 is deleted from the measurement result in step S20 (step S40). As described above, the measurement result obtained in step S20 includes the shape of the coil spring W and the shapes of the holding jigs 12 and 14. Here, from the position of the holding jigs 12 and 14 detected in step S22, the measurement result (data) obtained in step S20 is data representing the shape of the holding jigs 12 and 14, or the shape of the coil spring W. It is possible to determine whether the data is data to be represented. In step S40, the arithmetic unit 32 deletes the shape data of the holding jigs 12 and 14 from the measurement result of step S20 using the positions of the holding jigs 12 and 14 detected in step S22.

  Next, the arithmetic unit 32 interpolates the data omission of the measurement data (shape data of the coil spring W) obtained in step S20 (step S42). That is, when there is a gap in the measurement data, the data gap is interpolated using the measurement data before and after the measurement data where the gap has occurred. Next, the intervals of the measurement data groups obtained in step S42 are made uniform (S44), and the data groups are smoothed (S46). And the strand of the coil spring W is detected by fitting the obtained data group in a circular shape (S48).

  When the strand of the coil spring W is detected in step S48, the process returns to step S26 in FIG. 5 to estimate the coil diameter of the coil spring W (S26). That is, the spring element wire of the coil spring W is detected from the measurement result of step S20. As described above, the measurement in step S20 is performed at four locations in the circumferential direction of the coil spring W, and the coil spring W is not continuously measured in the circumferential direction. For this reason, the computing device 32 estimates the coil diameter of the coil spring W from the shape of the spring wire of the coil spring W detected in step S24 (the shape of the four circumferential directions). The coil spring W to be measured includes a cylindrical coil spring having a constant coil diameter and a spring (for example, a barrel spring, a conical spring, etc.) whose coil diameter changes in the axial direction. In the case of a cylindrical coil spring, the coil diameter estimated in step S26 is a constant value, and in the case of a spring such as a barrel spring, the coil diameter estimated in step S26 varies depending on the position in the axial direction.

(Wire position prediction process)
When the coil diameter of the coil spring W is estimated in step S26, the process returns to step S14 in FIG. 4 and the predicted wire position (θ _s , z _{s) of the} coil spring W that will be measured during the detailed measurement in the next step S16. , R _s ) is calculated (S14). Here, theta _s is the angle of rotation for positioning the coil spring W during detailed measurement, z _s is the predicted position in the z direction of the spring wire which is measured during detailed measurement (expected height), r _s details This is the predicted position (corresponding to the predicted coil diameter) of the spring element wire measured at the time of measurement. The computing device 32 uses the strand position (θ _i , z _ij , r _ij ) of the coil spring W acquired by the rough measurement process in step S12 to predict the strand position (θ _s ) of the coil spring W during the detailed measurement. , Z _s , r _s ).

The process of step S14 will be described in detail. The arithmetic device 32 obtains the approximate shape of the coil spring W by the rough measurement process in step S12. That is, the wire position (θ _i , z _ij , r _ij ) of the coil spring W is acquired for each of the rotation angles θ _i (i = 1 to n (for example, 4)) for which the rough measurement was performed. (Ij represents the wire detection order j (j-th winding) at the rotation angle θ _i .) Since the coil spring W is formed by spirally winding a spring wire, the arithmetic unit 32 is First, the strand positions (θ _i , z _ij , r _ij ) of the coil spring W acquired by the rough measurement process are rearranged in the order along the strands of the coil spring W. Specifically, in order from the position of the wire corresponding to the end of the coil spring W, the position of the wire adjacent to the position of the wire along the wire of the coil spring is specified. The same process is repeated until it reaches. Thereby, each of the strand positions (θ _i , z _ij , r _ij ) acquired in step S12 is associated with the adjacent strand position.

This will be specifically described with reference to FIG. In FIG. 3, the position z _{ij in the} height direction among the strand positions (θ _i , z _ij , r _ij ) acquired for the four rotation angles by the rough measurement process is along the strand of the coil spring W. Sorted. That is, in step S12, z ₁₁ ,... Is acquired for a rotation angle of 90 °, z ₂₁ , z ₂₂ ,... Are acquired for a rotation angle of 180 °, and z ₃₁ , z ₃₂ ,. .., And z ₄₁ , z ₄₂ ,... Are acquired for a rotation angle of 360 °. Then, z ₃₁ , z ₄₁ , z ₁₁ , z ₂₂ , z ₃₂ ... Are specified in order from z ₂₁ located at one end of the coil spring W. Thus, for _example, it is found a point adjacent to the _{z 11} is the _{z 41} and _{z 22.}

As described above, if the strand positions (θ _i , z _ij , r _ij ) of the coil spring W acquired by the coarse measurement process are rearranged along the strands of the coil spring W, then the measurement is performed during the detailed measurement. for each rotation angle theta _s performed, the will be measured in the rotation angle theta _s strand predicted position _{(θ s, z s, r} s) is calculated. That is, when the rotation angle θ _s is determined, the wire of the coil spring W measured at the rotation angle θ _s is any of the wire positions (θ _i , z _ij , r _ij ) acquired by the rough measurement process. Whether it is located between two points can be specified. For example, as shown in FIG. 3, when the rotation angle θ _s is located between 180 ° and 270 °, the wire of the coil spring W is measured between the point z ₂₁ and the point z _31. it can be seen that measured between the z ₂₂ and the point _{z 32.} Thus, strands predicted position of the coil spring _{W (θ s, z s,} r s) exist to interval (i.e., two strands position (theta _{i, z ij,} interval defined by _{r ij))} calculated but Once identified, the two strands positions _{(θ i, z ij, r} ij) strand predicted position using the data of _{(θ s, z s, r} s) of interpolation (interpolation) To do. For example, two strands positions _{(θ i, z ij, r} ij) in section specified in, _{r s} and _{z s} is assumed to vary linearly, and calculates the predicted position _{r s} and _{z s.} Thereby, the strand predicted position (θ _s , z _s , r _s ) at the time of detailed measurement is calculated.

(Detailed measurement process)
When the strand position prediction process in step S14 ends, the arithmetic device 32 then executes a detailed measurement process that measures the entire shape of the coil spring W in detail (step S16). The detailed measurement process will be described with reference to FIG.

In detail the measurement processing as shown in FIG. 6, first, the arithmetic unit 32, wire predicted position calculated in step _{S14 (θ s, z s,} r s) rotating mechanism 16 and the adjustment device based on the (20, 22 , 26 to 30), and the surface shape of the coil spring W is measured by the laser displacement meter 24 while adjusting the position and laser irradiation angle of the laser displacement meter 24 (S30). Since the wire predicted position of the coil spring W by the step _{S14 (θ s, z s,} r s) is computed, at step S30, the laser displacement gauge 24 wire predicted position _{(θ s, z s, r} s ) In order, the surface shape of the coil spring W is measured.

Specifically, the arithmetic unit 32 first strand predicted position calculated in step _{S14 (θ s, z s,} r s) and to the order along the wire of the coil spring W. The rearranging method is performed by the same method as that in step S14 described above. Thereby, the strand predicted positions (θ _s , z _s , r _s ) are arranged in order from one end side to the other end side of the coil spring W. Next, the position (z direction and r direction) of the laser displacement meter 24 and the rotation mechanism 16 when measuring the coil springs W at the respective predicted wire positions (θ _s , z _s , r _s ) in the rearranged order. The rotation angle of is calculated. That is, the position of the laser displacement meter 24 (z direction and r direction) and the rotation of the rotation mechanism 16 so that the predicted wire position (θ _s , z _s , r _s ) is positioned at the center of the field of view of the laser displacement meter 24. Calculate the corner. Specifically, the position in the z direction of the laser displacement meter 24 and the predicted position z _s, and left the position of r direction of the laser displacement gauge 24 from the predicted position r _s by a predetermined distance (distance suitable for measurement) position The rotation angle of the rotation mechanism 16 is set so that the position of the rotation angle θ _s of the coil spring W _faces the laser displacement meter 24. As is apparent from the above description, (if not cylindrical coil spring) may change the wire predicted position r _s, by the laser displacement meter 24 is displaced in the direction r, the distance between the coil spring W Maintained at an appropriate distance.

Next, the arithmetic unit 32 drives the rotating mechanism 16 and the adjustment device (20,22,26～30), rearranged strand predicted position _{(θ s, z s, r} s) in this order, the The laser displacement meter 24 is sequentially positioned at a position corresponding to the predicted wire position (θ _s , z _s , r _s ), and the surface shape of the coil spring W is measured. Here, the strand predicted positions (θ _s , z _s , r _s ) are rearranged in the order along the strands of the coil spring W, and the laser displacement meter 24 has the rearranged strand predicted positions (θ _s , Z _s , r _s ) in order, the laser displacement meter 24 measures the surface shape of the coil spring W while moving relative to the coil spring W in a spiral manner. As a result, setting small angular interval of the rotation angle theta _s in detail the measurement process, it is possible to suppress the time required to measure the surface shape of the coil spring W becomes long. In step S30, the irradiation angle of the laser light emitted from the laser displacement meter 24 is adjusted so as to be an angle orthogonal to the rotation axis of the holding jigs 12 and 14, as in step S20.

  Next, the computing device 32 processes the measurement result of step S30 and detects the shape of the spring element wire of the coil spring W (step S32). The process of step S32 is performed in the same manner as the process of step S24 already described (that is, the process of FIG. 7). Next, the computing device 32 updates the spring shape data with the wire data of the coil spring W detected in step S32 (S34). As a result, the spring shape data is replaced with the measurement data measured in detail in step S16.

(Shape data output processing)
When the detailed measurement process in step S16 ends, the arithmetic device 32 executes a shape data output process for outputting the created shape data of the coil spring W (step S18). Specifically, the arithmetic unit 32 outputs the created shape data to a monitor (not shown). The monitor displays the coil spring W based on the created shape data. Therefore, the operator can grasp the overall shape of the coil spring W from the coil spring W displayed on the monitor.

As described above, in the shape measuring apparatus 10 of the present embodiment, the predicted strand position (θ _s , z _s , r) using the strand position (θ _i , z _ij , r _ij ) acquired in the rough measurement process. _s ), and based on the calculated strand predicted position (θ _s , z _s , r _s ), the laser displacement meter 24 is moved with respect to the coil spring W to measure the shape of the coil spring W in detail. . For this reason, even if it performs a detailed measurement process with a small rotation angle space | interval, it can suppress that the measurement of the surface shape of the coil spring W takes long time. Therefore, the shape of the coil spring W can be accurately measured in a short time. Further, in detail the measurement process, strand predicted position _{(θ s, z s, r} s) is controlled so that the center of the field of view of the laser displacement meter 24, also the distance between the laser displacement meter 24 and the coil spring W Is controlled to be an appropriate distance. This also makes it possible to accurately measure the shape of the coil spring W.

  Next, the shape measuring apparatus 130 according to the second embodiment will be described with reference to FIG. Hereinafter, only differences from the first embodiment will be described, and detailed description of the same configurations as those of the first embodiment will be omitted. The same applies to Example 3. The shape measuring apparatus 130 of the present embodiment uses a pattern projection sensor 144 that is a kind of a non-contact displacement meter, instead of the laser displacement meter 24. The pattern projection type sensor 144 is a three-dimensional sensor having a surface light source, and irradiates the measurement target with planar pattern light from two directions intersecting each other.

Specifically, the pattern projection sensor 144 includes two irradiation units 146a and 146b that are spaced apart in the Z-axis direction, and a light receiving surface 148 that is disposed between the two irradiation units 146a and 146b, It has a processor (not shown). The two irradiation units 146a and 146b respectively irradiate the same part of the coil spring W with pattern light (strictly, the two pattern lights irradiate at least part of the coil spring W). The pattern light is a planar light having a stripe pattern, and on the optical axis of the pattern light (the central axis of the planar pattern light, indicated by a broken line in FIG. 8), the rotation axes of the holding jigs 12 and 14 Is located. By moving the pattern projection type sensor 144 in the Z-axis direction, the pattern light is irradiated to the entire axial direction of the coil spring W.
The light receiving surface 148 includes a light receiving element such as a CMOS, and receives light reflected from the coil spring W (that is, pattern light irradiated from the irradiation units 146a and 146b and reflected from the same portion of the coil spring W). To do. The optical axes of the light emitted from the irradiation units 146 a and 146 b cross obliquely with respect to the axis perpendicular to the light receiving surface 148. The light receiving surface 148 is parallel to the rotation axis of the holding jigs 12 and 14 and receives reflected light from the coil spring W from the front (in a direction orthogonal to the axis).
The processor analyzes the reflected light received by the light receiving surface 148, and generates the three-dimensional shape of the coil spring W at the irradiation site of the pattern light in real time. The calculation device 32 stores the operation state of the drive mechanism (16, 18) and the adjustment device (20, 22, 26-30) and the measurement result output from the pattern projection sensor 144 in association with each other and stored. The shape of the coil spring W is generated in three dimensions from the information.
Similar to the shape measuring apparatus 10 of the first embodiment, the shape measuring apparatus 130 also calculates the shape of the coil spring W by performing each step shown in FIG.

According to the shape measuring apparatus 130 of the present embodiment, the same effects as the shape measuring apparatus 10 of the first embodiment can be achieved. In addition, the laser displacement meter 24 acquires two-dimensional data of (z, r), whereas the pattern projection sensor 144 has three-dimensional data of (θ, z, r) (or (x, z, r)). Can be obtained. That is, the pattern projection type sensor 144 can acquire data of a plurality of angles by one irradiation (see FIGS. 9 and 10). For this reason, by using the pattern projection type sensor 144, it is possible to increase the measurement angle interval and reduce the number of times the rotary stage is driven. As a result, the measurement time can be further shortened.
Note that there are various types of pattern light projectors mounted on the pattern projection sensor 144. For example, as a pattern light projection device, a “laser modulation grating projection device that projects lattice-like light (hereinafter sometimes simply referred to as a grating) by scanning with a one-dimensional resonant scanner while modulating the output of a line laser. May be used. Also, use a pattern projection light sensor equipped with "multi-line LED grating projector" or "multi-path grating projector" that shifts the phase of the grating at high speed by using multiple LEDs as light source and switching them May be. Alternatively, a pattern projection light sensor equipped with an “interference fringe projection device” that projects interference fringes generated by superimposing beams divided into two by a beam splitter may be used. Further, a pattern projection light sensor equipped with a device for projecting a stripe pattern by a liquid crystal projector may be used. Further, as a pattern projection / analysis method, a spatial code encoding method may be used, a phase shift method may be used, or high accuracy analysis may be performed using the two in combination. An arithmetic device for analyzing the image of the fringe pattern may be incorporated in the pattern projection type sensor, or a computer connected to the pattern projection type sensor may be used as the arithmetic device. It is also conceivable to increase the measurement accuracy by projecting a mixture of light of a plurality of wavelengths as the pattern light and receiving the reflected light by a light receiving sensor corresponding to each wavelength. For example, a fringe pattern formed by appropriately mixing red light (R), green light (G), and blue light (B) as projection light is projected, received by a color CCD camera having RGB elements, and received by R elements. It is also conceivable to improve the two-dimensional distance analysis accuracy by combining and analyzing the received light image, the image received by the G element, and the image taken by the B element. By appropriately combining these projection methods and image analysis algorithms, it is possible to configure a pattern projection type sensor that can measure with higher accuracy and higher speed than a laser displacement meter.
In this embodiment, the irradiation units 146a and 146b and the light receiving surface 148 of the pattern projection type sensor are arranged along the Z-axis direction. However, the positional relationship between the irradiation units 146a and 146b and the light receiving surface 148 is limited to this. Absent. For example, the irradiation units 146a and 146b and the light receiving surface 148 may be arranged horizontally (that is, on a plane substantially orthogonal to the Z axis).

  Next, the shape measuring apparatus 230 according to the third embodiment will be described with reference to FIG. The shape measuring apparatus 230 of this embodiment uses an optical sensor 244 using a wavelength confocal method instead of the laser displacement meter 24. The optical sensor 244 is a kind of non-contact displacement meter, and irradiates the measurement target with white light (illustrated by a broken line in FIG. 11).

The optical sensor 244 includes therein a light source 246, a plurality of lenses (not shown), a confocal filter (not shown), and a spectrometer (not shown). The light source 246 is provided at one end of the optical sensor 244 in the axial direction (r-axis direction), and emits white light in the axial direction toward the other end. The plurality of lenses are arranged in the axial direction inside the optical sensor 244. The confocal filter is provided on the path of reflected light (described later) from the measurement object (coil spring W). The spectroscope is provided behind the confocal filter in the traveling direction of the reflected light (that is, the side opposite to the side where the coil spring W is disposed with respect to the confocal filter).
The white light emitted from the light source 246 passes through the plurality of lenses and is decomposed into a plurality of monochromatic lights by the chromatic aberration of the lenses. The white light decomposed into a plurality of monochromatic lights is applied to the surface of the coil spring W. White light is irradiated in the direction in which the rotation axes of the holding jigs 12 and 14 are positioned on the optical axis. By moving the optical sensor 244 in the Z-axis direction, white light is irradiated to the entire axial direction of the coil spring W. Of the reflected light (not shown) reflected from the surface of the coil spring W, only the monochromatic light having the wavelength focused on the surface of the coil spring W passes through the confocal filter, and the monochromatic light that is not focused is the confocal light. All are blocked by the focal filter. The light that has passed through the confocal filter is detected by the spectroscope, and the detection result is output to the arithmetic unit 32. The arithmetic device 32 stores the operating state of the drive mechanism (16, 18) and the adjusting device (20, 22, 26-30) and the detection result output from the optical sensor 244 in association with each other, and from the stored information The shape of the coil spring W is generated.
The optical sensor 244 irradiates the coil spring W with white light from a direction orthogonal to the rotation axis of the holding jigs 12 and 14. Similar to the shape measuring apparatus 10 of the first embodiment, the shape measuring apparatus 230 also calculates the shape of the coil spring W by performing each step shown in FIG.

  Also with the shape measuring apparatus 230 of the present embodiment, the same operational effects as those of the shape measuring apparatus 10 of the first embodiment can be achieved. Further, by using the optical sensor 244 using the wavelength confocal method, it is possible to appropriately measure even when the surface of the coil spring W is a mirror surface or a rough surface. Further, since the shape measurement is performed only from the reflected light focused on the surface of the coil spring W, an excellent spatial resolution can be obtained with little influence from ambient light. When a plurality of wavelength confocal point measurement sensors are arranged linearly at intervals so that measurement light does not interfere with each other, a line sensor is formed, and when a plurality of wavelength confocal point measurement sensors are arranged in a plane, an area sensor is formed. These line sensors and area sensors can be mounted as non-contact displacement meters. Further, the wavelength confocal (chromatic confocal) sensor is designed so that the incident angle and the reflection angle of the measurement light are substantially equal.

  Although the present embodiment has been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.

For example, in the above embodiment, the laser displacement meter 24 is moved spirally with respect to the coil spring W in the detailed measurement process, but the driving method of the laser displacement meter 24 is not limited to such a method. For example, similarly to the coarse measurement process of step S12, the positioning of the rotation angle theta _s of the coil spring W, it may be performed separately and movement in the z direction of the laser displacement gauge 24. Even in such a driving method, since wire predicted position _{(θ s, z s, r} s) is other than it is not necessary to measure the shape of the coil spring W, high-speed movement between adjacent strands predicted position Can be done. For this reason, even if the laser displacement meter 24 is driven by such a driving method, it is possible to suppress an increase in measurement time. The same applies to other non-contact displacement gauges.

  In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

10: shape measuring device 12, 14: holding jig 16: rotating mechanism 18: reciprocating mechanism 20: r direction guide rail 22: z direction guide rail 24: laser displacement meter 26: irradiation angle adjusting mechanism 28: z direction position adjustment Mechanism 30: r-direction position adjustment mechanism 32: arithmetic unit 34: 36, 38, 40, 42, 44, 46: measurement range 50: calibration jig W: coil spring

Claims (6)

A shape measuring method for measuring the shape of a coil spring,
An arrangement step of arranging the coil spring so that both ends of the coil spring are located on a preset axis;
For each of a plurality of rotation angles when the non-contact type displacement meter is rotated relative to the coil spring at a first angular interval around the axis, the non-contact type displacement meter is arranged with respect to the coil spring. A first measurement step of measuring the surface shape of the wire of the coil spring while relatively moving linearly in a direction parallel to
The first measurement step for each of a plurality of rotation angles when the non-contact displacement meter is rotated relative to the coil spring at a second angular interval smaller than the first angular interval around the axis. A second measuring step of measuring the surface shape of the coil spring wire by moving the non-contact displacement meter to the coil spring to the predicted position of the coil spring wire predicted from the measurement result of
A method for measuring the shape of a coil spring.   In the second measurement step, the coil spring and the non-contact displacement meter are adjusted by adjusting the position of the non-contact displacement meter in the radial direction of the coil spring based on the coil diameter predicted from the measurement result of the first measurement step. The shape measuring method of the coil spring according to claim 1, wherein the distance to the coil spring is adjusted.   The shape measuring method of the coil spring according to claim 1 or 2, wherein, in the second measuring step, the non-contact displacement meter moves so that the predicted position is located at the center of the visual field of the non-contact displacement meter. In the first measurement process,
A first step of rotating a non-contact displacement meter relative to a coil spring relative to the axis by a first angle;
A second step of measuring the surface shape of the wire of the coil spring while linearly moving the non-contact displacement meter relative to the coil spring in a direction parallel to the axis;
The method of measuring the shape of the coil spring according to any one of claims 1 to 3, wherein the step is repeatedly executed.   In the second measurement step, the non-contact displacement meter moves linearly relative to the coil spring along the axial direction of the coil spring and simultaneously rotates relative to the coil spring around the axis. The shape measurement method of the coil spring according to claim 1, wherein a non-contact displacement meter moves to the predicted position. A shape measuring device for measuring the shape of a coil spring;
A holding jig for holding the coil spring so that both ends of the coil spring are located on a preset axis;
A non-contact displacement meter capable of measuring the surface shape of the coil spring held by the holding jig;
An adjustment mechanism for adjusting the position of the non-contact displacement meter with respect to the coil spring held by the holding jig,
For each of a plurality of rotation angles when the non-contact displacement meter is rotated relative to the coil spring at a first angular interval around the axis, the non-contact displacement meter is adjusted with respect to the coil spring by the adjusting mechanism. Measuring the surface shape of the wire of the coil spring with a non-contact displacement meter, while relatively linearly moving in the direction parallel to the axis,
For each of a plurality of rotation angles when a non-contact displacement meter is rotated relative to the coil spring at a second angular interval smaller than the first angular interval around the axis, The non-contact displacement meter is moved relative to the coil spring by the adjusting mechanism to the predicted position of the coil spring strand predicted from the measurement result of the surface shape of the wire, and the coil spring strand is also moved by the non-contact displacement meter. Coil spring shape measuring device that measures the surface shape of