Shape measurement system and shape measurement method

Abstract

To measure a tooth profile, a tooth muscle and a diameter of a gear regardless of a diameter of the gear.SOLUTION: The present disclosure proposes a shape measurement system that measures a shape of a gear, as an example, the shape measurement system including a reference jig having a gear placement surface on which the gear to be measured is placed, at least one optical sensor that irradiates the reference jig and the gear with light to make measurement, a linear motion stage that linearly moves the reference jig and the gear in a direction along the gear placement surface, and a controller that outputs a measurement result of the shape of the gear on the basis of measurement data by at least one optical sensor. The linear motion stage and the at least one optical sensor are configured so that an area over the reference jig and the gear across the gear placement surface is irradiated with the light from the optical sensor when the reference jig and the gear are moved straight on the linear motion stage. The controller applies alignment data for known contour shape data of the measurement data of the reference jig to the measurement data of the gear to acquire the shape of the gear.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a shape measurement system and a shape measurement method. [Background technology]

[0002] Power transmission devices are core components of various products, including automobiles, construction machinery, and aircraft. The machining accuracy of gears is an important factor that determines the performance of power transmission devices, and quality control of gear shapes is essential to ensure transmission performance. In particular, the tooth profile, tooth trace, and diameter must be machined with high precision because they are directly related to the meshing of gears. For example, the N9 precision gear specified in JIS B 1702-1 is stipulated to have a tooth trace error of 34 μm or less when the dimensions are a diameter of 500 mm and a tooth depth of 20 mm. As such, gears require high machining accuracy, and precise measurement is necessary for quality control of gear shapes. On the other hand, in order to achieve 100% inspection on the production line, it is desirable to have a short measurement time.

[0003] The mainstream method for measuring gears is to use a contact probe. This method measures the gear shape by placing a probe on the tooth surface and moving the probe or by rotating the gear. However, while this method can provide highly accurate measurements, it has the problem of taking a long time to measure.

[0004] In this context, in order to provide a highly accurate and quick measurement method, shape measurement systems using non-contact methods such as optical sensors have been proposed in recent years. For example, Patent Document 1 proposes a device in which multiple optical sensors are oriented relative to a gear and the gear is rotated to measure the overall shape. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2018-537693 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in Patent Document 1, because measurements are taken while the gear is rotating, if an angle error occurs in the rotary encoder, the measurement accuracy deteriorates in proportion to the size of the gear. For example, if the gear diameter is 500 mm, and the encoder angle error is 10 seconds (10° / 3600), a measurement error of 12 μm will occur. In view of these circumstances, the present disclosure provides a shape measurement technology capable of measuring the tooth profile, tooth trace, and diameter of a gear with high accuracy regardless of the size of the gear. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the present disclosure proposes, as an example, a shape measurement system for measuring the shape of a gear, comprising: a reference jig having a gear mounting surface on which the gear to be measured is mounted; at least one optical sensor that performs measurement by irradiating light onto the reference jig and the gear; a linear stage that moves the reference jig and the gear linearly in a direction along the gear mounting surface; and a controller that outputs measurement results of the gear shape based on measurement data from the at least one optical sensor, wherein the linear stage and the at least one optical sensor are configured such that light from the optical sensor is irradiated across the reference jig and the gear across the gear mounting surface when the reference jig and the gear move linearly on the linear stage, and the controller obtains the shape of the gear by applying alignment data for data of a known contour shape of the measurement data of the reference jig to the measurement data of the gear.

[0008] Further features related to the present disclosure will be apparent from the description of the present specification and the accompanying drawings. Also, the aspects of the present disclosure are achieved and realized by the elements and combinations of various elements and the following detailed description and the appended claims. Note that the description of the present specification is merely a typical example and does not limit the scope or application of the present disclosure in any way. Effect of the Invention

[0009] According to the technology disclosed herein, a reference jig with a known shape is measured at the same time as the gear, and the reference jig is used as a reference for alignment when synthesizing partial shape data, thereby eliminating the effect of angular error of the rotary encoder on the synthesis accuracy of the gear's entire shape. As a result, it is possible to measure and evaluate the gear's entire shape with high accuracy, regardless of the gear size. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing an example of a schematic top configuration of a shape measurement system 1 according to a first embodiment. [Diagram 2] 1 is a diagram showing an example of a schematic front configuration of a shape measurement system 1 according to a first embodiment. [Diagram 3] 5 is a flowchart for explaining gear measurement processing according to the first embodiment. [Figure 4] 4A to 4C are diagrams showing measurement results of arbitrary cross sections of the gear 100 and the reference jig 101 measured by the optical sensors 201 and 202 in step S102 of FIG. 3. [Diagram 5] FIG. 1 is a diagram showing a concept of synthesizing partial shape data of a gear 100 and a reference jig 101 measured by an optical sensor 201. [Figure 6] FIG. 2 is a diagram for explaining the concept of synthesizing partial shape data of the gear 100 and the reference jig 101 measured by the optical sensor 202. [Figure 7] FIG. 2 shows an example of the overall shape of gear 100 obtained by combining partial shape data of gear 100 and reference jig 101 measured by optical sensors 201 and 202. [Figure 8] FIG. 13 is a diagram (top view) showing a schematic configuration example of a shape measuring system 1A according to a second embodiment. [Figure 9] 11 is an enlarged view (top view) of the periphery of a gear 100 of a shape measurement system 1A according to a second embodiment. [Figure 10] FIG. 11 is a diagram showing an example of a schematic front configuration of a measurement system 1A according to a second embodiment. [Figure 11] 10 is a flowchart for explaining gear measurement processing according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] This embodiment discloses a method in which a gear to be measured, which is placed on a reference jig whose contour shape and dimensions are known, is measured together with the reference jig using an optical sensor, and coordinate transformation values ​​(translation and rotational movement) are calculated for the measurement data of the reference jig based on the coordinate data of the reference jig in a virtual space, and the coordinate transformation values ​​are applied to the measurement data of the gear to draw the gear shape (shape synthesis) and measure (calculate) the shape and dimensions of the target gear.

[0012] Hereinafter, an embodiment of the present disclosure will be described with reference to the accompanying drawings. In the accompanying drawings, functionally identical elements may be indicated by the same numbers. Note that the accompanying drawings show specific embodiments and implementation examples according to the principles of the present disclosure, but these are for understanding the technology of the present disclosure and are by no means used to interpret the technology of the present disclosure in a limited manner.

[0013] In the present embodiment, the description is given in sufficient detail for a person skilled in the art to implement the present disclosure, but it should be understood that other implementations and forms are possible, and that changes in configuration and structure and substitutions of various elements are possible without departing from the scope and spirit of the technical ideas of the present disclosure. Therefore, the following description should not be interpreted as being limited thereto.

[0014] Furthermore, the embodiments of the present disclosure, as described below, may be implemented in software running on a general-purpose computer, or may be realized in dedicated hardware, or a combination of software and hardware.

[0015] (1) First embodiment The first embodiment will be described with reference to FIGS. <Configuration example of shape measurement system 1> 1 and 2 are a top view and a front view, respectively, showing a schematic configuration example of a shape measurement system 1 according to this embodiment.

[0016] Shape measurement system 1 has gear 100 as a measurement target, and includes reference jig 101 with a known shape used for alignment when synthesizing the gear's entire circumference shape, a fixing mechanism (not shown) for gear 100 and reference jig 101, rotation stage 102, linear stage 103, controller 104, computer 105, and optical sensors 201 and 202 that measure the shapes of gear 100 and reference jig 101 using a light cutting method. Note that here, controller 104 and computer 105 are separate, but computer 105 may be configured to have the functions of controller 104. Also, although two optical sensors are provided in this embodiment, three or more optical sensors may be provided.

[0017] The material of the gear 100 may be, for example, steel. The gear specifications may be, for example, module number 15, number of teeth 12, height 60 mm, and precision N9 class. In the case of the gear specifications shown in the example, the tip circle diameter is 215.8 mm, the tooth depth is 33.7 mm, the allowable error of the tooth profile is 60 μm, and the allowable error of the tooth trace is 36 μm. The precision of the diameter is about the general tolerance, and in the case of the gear 100, the tolerance is 200 μm.

[0018] The optical sensors 201 and 202 are arranged so as to measure the tooth surfaces of the gear 100 in different directions (side faces). For example, in this embodiment, the optical sensors 201 and 202 are optical devices including a light emitting unit (light source) including a semiconductor laser or the like, an optical system including a light projecting lens and a light receiving lens, and a light receiving unit (light receiving element) that receives the light focused by the light receiving lens. In this embodiment, the optical sensors 201 and 202 are arranged symmetrically with respect to a line 12 that passes through the center O of the reference jig 101 and is parallel to the y-axis (the moving direction of the linear stage 103). In addition, the distance between the optical sensor 201 and the tooth bottom of the gear 100, that is, the line segment S1-R1 in FIG. 1, is set to 180 mm. Similarly, the line segment S2-R1' between the optical sensor 202 and the tooth bottom of the gear 100 is also set to 180 mm. It is preferable that the optical sensors 201 and 202 are the same sensor in order to unify the measurement accuracy. Furthermore, the linearity of optical sensors 201 and 202 is ±0.01%. When the tooth depth of gear 100 is 33.7 mm, the measurement accuracy in the direction of optical axis 21a is ±3.37 μm. Since the measurement accuracy is 1 / 10 or less of the tolerances of the tooth profile, tooth lead, and diameter, it can be said that optical sensors 201 and 202 have sufficient measurement accuracy.

[0019] The gear 100 is placed on the gear mounting surface 108 of the reference jig 101 and fixed to the reference jig 101 (a fixing mechanism is not shown). The reference jig 101 is a regular polygonal prism with a known shape having the same number of vertices as the number of teeth of the gear 100, and in this embodiment is a regular dodecagonal prism. The reference jig 101 has the bottom surface (upper surface) of the polygonal prism as the gear mounting surface 108. Since the optical sensors 201 and 202 measure the gear 100 and the reference jig 101, the tooth trace T1-R1 of the gear 100 and the contour of the reference jig 101 must fall within the measurement range MR1 in the direction of the optical axis 21a. Similarly, the tooth trace T1'-R1' of the gear 100 and the contour of the reference jig 101 must fall within the measurement range MR2 in the direction of the optical axis 22a of the optical sensor 202. In this embodiment, the measurement ranges MR1 ​​and MR2 are 80 mm, so the length of the opposing sides of the reference jig 101 is set to 220 mm, and the gear 100 is placed on the reference jig 101 so that the tooth traces T1-R1 and T1'-R1' of the gear 100 and the contour of the reference jig 101 fall within the measurement ranges MR1 ​​and MR2.

[0020] The height of reference jig 101 is 30 mm, and the shape precision is about 1 / 10 of the gear diameter tolerance, i.e., 20 μm. Gear 100 and reference jig 101 are measured with the same optical sensor, so it is desirable that the reflection characteristics of their surfaces are the same.

[0021] The reference jig 101 is mounted on a rotating stage 102. The rotation axis 11 of the rotating stage 102 and the center point O of the reference jig 101 are aligned. The rotating stage 102 is mounted on a linear stage 103. The linear stage 103 is driven in the y-axis direction in Figure 1. The optical sensors 201 and 202 measure a part of the gear 100 while the linear stage 103 is moving in the y-axis direction.

[0022] The computer 105 reads a program for executing the processing of a flowchart described below (see FIG. 3) from a memory (not shown), and instructs the controller 104 to control the necessary operations based on the program. In response to instructions given from the computer 105, the controller 104 controls the rotation of the rotation stage 102 (operation of the rotary encoder), the linear movement of the linear movement stage 103, the irradiation of light by the optical sensors 201 and 202, and the like.

[0023] As shown in Fig. 2, the optical sensors 201 and 202 are installed so that the longitudinal direction of the spread (radiation angle φ) of the line beams 21 and 22 emitted from the sensors is parallel to the z-axis. Here, the radiation angle φ of the line beams 21 and 22 is, for example, 26.7°, and the length (longitudinal length) of the line beams 21 and 22 on the tooth surface of the gear 100 is approximately 80 mm. In this embodiment, the irradiation range of the line beams 21 and 22 in the line direction is set so that the line beams 21 and 22 are irradiated across the gear mounting surface 108 of the reference jig 101 and across the side surfaces of the gear 100 and the reference jig 101. This makes it possible to measure the shapes of the gear 100 and the reference jig 101 simultaneously.

[0024] <Gear measurement processing> 3 is a flowchart for explaining the gear measurement process according to the first embodiment. In the following explanation, the subject of operation of each step is the controller 104 or the computer 105. If the computer 105 has the functions of the controller 104, the subject of operation is the computer 105.

[0025] (i) Step S101 After the user (operator) places and fixes the gear 100 to be measured on the reference jig 101, the user (operator) inputs an instruction to start measurement using an input device of the computer 105. The controller 104 then receives from the computer 105 the command to start measurement, along with information on the movement distance (one movement step) of the linear stage 103 during one measurement process, and initializes the operations of the optical sensors 201 and 202, the rotation stage 102, and the linear stage 103.

[0026] (ii) Step S102 The controller 104 controls the linear stage 103 and the optical sensors 201 and 202 to measure the tooth surface of the gear 100 and the partial shape of the reference jig 101 while moving the gear 100 and the reference jig 101 in a straight line for a distance of one movement step in the y-axis direction in Fig. 1. The measurement range corresponds to the distance of one movement step and includes at least one tooth of the gear 100 and one vertex of the reference jig 101. The controller 104 sends the data acquired in one measurement process (measurement data of the reference jig 101 and measurement data of the gear 100) to the computer 105. The computer 105 stores the received measurement data in a memory (not shown) until all the data has been acquired.

[0027] (iii) Step S103 The computer 105 checks whether the measurement process has been completed for the entire circumference of the gear 100. If measurement data for the entire circumference of the gear 100 has been acquired (Yes in step S103), the process proceeds to S105. If measurement data for the entire circumference of the gear 100 has not yet been acquired (No in step S103), the process proceeds to S104.

[0028] (iv) Step S104 In response to a command from the computer 105, the controller 104 controls the rotating stage 102 to rotate the gear 100 and the reference jig 101 by an arbitrary angle around the rotation axis 11. The rotation angle can be, for example, 360° / N based on the number of teeth N of the gear 100. When the number of teeth N=12, the angle is 360° / 12=30°. By measuring each tooth at a rotation angle of 360° / N, the incidence conditions of the line beams 21 and 22 are the same for all teeth of the gear 100. As described above, any angle can be used for the rotation angle, but by setting the rotation angle to 360° / N, the positional relationship between each tooth of the gear 100 and the optical sensor 201 or the optical sensor 202 can be made reproducible for each measurement, so that each tooth can be measured under the same optical conditions. In other words, the measurement conditions are the same for all teeth of the gear 100.

[0029] (v) Step S105 When the computer 105 confirms that it has received measurement data for the entire circumference of the gear from the controller 104, it ends the measurement process.

[0030] (vi) Step S106 Computer 105 synthesizes each of the measured partial shapes of gear 100 to obtain the overall gear shape. At this time, the partial shape of reference jig 101 measured simultaneously with gear 100 in step S102 is used as a reference for alignment when synthesizing the overall gear shape.

[0031] <Gear Circumference Shape Synthesis Processing> The synthesis process of the entire circumference of a gear will be described with reference to Fig. 4 to Fig. 7. Fig. 4 shows the measurement results of an arbitrary cross section of the gear 100 and the reference jig 101 measured by the optical sensors 201 and 202 in step S102 in Fig. 3. In Fig. 4, the dotted lines indicate the actual shapes of the gear 100 and the reference jig 101, and the solid lines indicate the measurement ranges of the gear 100 and the reference jig 101. In step S102 in Fig. 3, the linear stage 103 is moved in the y-axis direction, and the optical sensors 201 and 202 irradiate the line beams 21 and 22 in the x-axis direction. However, the linear stage 103, the optical sensors 201 and 202, the line beams 21 and 22 are omitted in Fig. 4.

[0032] The range measured in step S102 is range A1 and range A1' (equivalent to one movement step of the linear stage) of about 40 mm in the y direction in Fig. 4. Measured shape 301 of reference jig 101 measured by optical sensor 201 is B1-V1-C1 including vertex V1, and measured shape 401 of gear 100 is Bg1-R1-T1-Cg1 including tooth trace R1-T1. Measured shape 301' of reference jig 101 measured by optical sensor 202 is B1'-V6-C1' including vertex V6. Measured shape 401' of gear 100 is Bg1'-R1'-T1'-Cg1' including tooth trace R1'-T1'.

[0033] FIG. 5 is a diagram showing a concept of synthesizing partial shape data of the gear 100 and the reference jig 101 measured by the optical sensor 201. A known contour shape 101' of the reference jig 101 is drawn in a virtual space (on a calculation coordinate system) for synthesizing point clouds. In FIG. 5, the contour shape 101' is indicated by a dotted line. The measured shape 301 of the reference jig 101 measured in step S102 of FIG. 3 is coordinate-transformed so as to overlap with a region including the vertex V1 of the contour shape 101' in the virtual space. That is, for example, first, a translation amount is calculated for superimposing the measurement data (coordinates) of the vertex V1 of the reference jig 101 on a point (coordinates) corresponding to the vertex V1 on the contour shape 101'. Next, a rotation amount (rotation angle) is calculated for superimposing the line segment V1-C1 of the measurement data on the line segment corresponding to the line segment V1-C1 in the contour shape 101'. The translation amount and rotation amount are calculated for the measurement data of each time, and become coordinate transformation values ​​for the measurement data of each time. Then, the partial shape 401 of the gear 100 is also subjected to the same coordinate transformation as that performed on the measured shape 301 of the reference jig (partial measured shape). Similarly, partial shape data of the gear 100 and the reference jig 101, whose measurement range includes vertices V2 to V12 of the reference jig 101, are synthesized based on the contour shape 101'. By the above processing, it is possible to synthesize the tooth flank shape of the gear 100 measured by the optical sensor 201.

[0034] Further, the tooth surface measured by the optical sensor 202 is subjected to the same synthesis process as the tooth surface measured by the optical sensor 201. FIG. 6 is a diagram for explaining the concept of synthesizing partial shape data of the gear 100 and the reference jig 101 measured by the optical sensor 202. As shown in FIG. 6, a known contour shape 101' of the reference jig 101 is drawn by a dotted line in the virtual space for point cloud synthesis. The measured shape 301' (partial measured shape) of the reference jig 101 measured in step S102 of FIG. 3 is coordinate-converted so as to overlap with a region including the vertex V6 of the contour shape 101' in the virtual space. At this time, the partial shape 401' of the gear 100 is also subjected to the same coordinate transformation as the measured shape 301' of the reference jig 101. Similarly, the partial shapes of the gear 100 and the reference jig 101 including the vertices V7 to V12 and V1 to V5 of the reference jig 101 in their measurement ranges are synthesized based on the contour shape 101'. In this way, it is possible to synthesize the tooth flank shape of the gear 100 measured by the optical sensor 202.

[0035] Fig. 7 shows an example of the overall shape of gear 100 obtained by combining partial shape data of gear 100 and reference jig 101 measured by optical sensors 201 and 202. It can be seen from Fig. 7 that measured shape 100' of gear 100 is a shape combining the overall shapes of one side of the gear shown in Fig. 5 and Fig. 6. In this way, because the common reference jig 101 is used as the reference for alignment with the partial shape data measured by optical sensors 201 and 202, it becomes possible to combine the overall shapes of both tooth surfaces of the gear.

[0036] <Advantages of the First Embodiment> According to the first embodiment, the following effects can be obtained. (i) By measuring the gear 100 while moving it in a straight line, the measurement accuracy is consistent regardless of the gear size. (ii) By using the reference jig 101 as a reference for alignment when synthesizing partial data of the gear 100, the entire peripheral shape of the gear 100 can be accurately evaluated.

[0037] (2) Second embodiment Next, as a second embodiment, an example in which the arrangement of sensors is changed will be described.

[0038] <Configuration example of shape measurement system 1A> (i) Overall configuration example FIG. 8 is a diagram (top view) showing a schematic configuration example of a shape measuring system 1A according to the second embodiment.

[0039] Shape measurement system 1A has gear 100 as a measurement target, and includes reference jig 101a with a known shape used for alignment when synthesizing the gear's entire circumference shape, a fixing mechanism (not shown) for gear 100 and reference jig 101a, rotation stage 102, controller 104, computer 105, optical sensors 201 and 202 that measure the shapes of gear 100 and reference jig 101, and linear stages 106 and 107 that drive optical sensors 201 and 202 in the z-axis direction. Note that here, controller 104 and computer 105 are separate, but computer 105 may be configured to have the functions of controller 104. Also, although two optical sensors are provided in this embodiment, three or more optical sensors may be provided.

[0040] The dimensions, shape, and material of the gear 100 are the same as those in the first embodiment. The reference jig 101a is a regular polygonal prism of known shape with the same number of vertices as the number of teeth of the gear 100, and in the second embodiment, it is a regular dodecagonal prism.

[0041] The specifications of the optical sensors 201 and 202 are the same as those in the first embodiment. The optical sensors 201 and 202 are installed so that the longitudinal direction of the spread (radiation angle ψ) of the line beams 21 and 22 emitted from the sensors is parallel to the y-axis in Fig. 8. The optical sensors 201 and 202 measure the tooth flanks of the gear 100 in different directions (side faces). In this embodiment, the optical sensors 201 and 202 are arranged symmetrically with respect to a straight line 12a that passes through the center Oa of the reference jig 101a and is parallel to the y-axis.

[0042] The gear 100 is placed on a reference jig 101a and fixed to the reference jig 101a (a fixing mechanism is not shown). The reference jig 101a is mounted on the rotation stage 102 so that the center point Oa coincides with the rotation axis 11 of the rotation stage 102.

[0043] (ii) Layout and dimensions Fig. 9 is an enlarged view (top view) of the periphery of gear 100 of shape measurement system 1A. An example of the positional relationship between optical sensors 201 and 202 and gear 100 and reference jig 101a, as well as an example of the dimensions of reference jig 101a will be described with reference to Fig. 9.

[0044] In the second embodiment, the optical sensor 201 is positioned so that the main optical axis 21a passes through the apex T1 of the tooth tip of the gear 100, and S1-T1 is 90 mm. Similarly, the optical sensor 202 is positioned so that the main optical axis 22a passes through the apex T1' of the tooth tip of the gear 100, and S2-T1' is 90 mm.

[0045] In order to measure the gear 100 and the reference jig 101a using the optical sensor 201, the tooth trace T1-R1 of the gear 100 and the contour of the reference jig 101a must fall within the measurement range MR1 of the optical sensor 201 in the direction of the optical axis 21a. Similarly, the tooth trace T1'-R1' of the gear 100 and the contour of the reference jig 101a must fall within the measurement range MR2 of the optical sensor 202 in the direction of the optical axis 22a. In this embodiment, the measurement ranges MR1 ​​and MR2 are 80 mm, so the length of the diagonal of the reference jig 101a is 220 mm, and the tooth trace T1-R1 and the contour of the reference jig 101a fall within the measurement range MR1, and the tooth trace T1'-R1' and the contour of the reference jig 101a fall within the measurement range MR2.

[0046] Furthermore, since the vertex of reference jig 101a is used as the reference point for alignment, the irradiation range in the y-axis direction of line beam 21 needs to include vertex V1 of reference jig 101a and tooth lead T1-R1 of gear 100. Similarly, the irradiation range in the y-axis direction of line beam 22 needs to include vertex V5 of reference jig 101a and tooth lead T1'-R1' of gear 100.

[0047] The reference jig 101a and the gear 100 are positioned so as to satisfy the above conditions. The height of the reference jig 101a is 30 mm, and the shape precision is about 1 / 10 of the gear diameter tolerance, i.e., 20 μm. Since the gear 100 and the reference jig 101a are measured by the same optical sensor, it is desirable that the reflection characteristics of their surfaces are the same.

[0048] (iii) Front configuration example 10 is a diagram showing an example of the front configuration of measurement system 1A according to the second embodiment. Optical sensors 201 and 202 are fixed to linear stages 106 and 107, respectively, and move in the z-axis direction to measure the shapes of gear 100 and reference jig 101a. Optical sensor 201 is controlled to move in the z-axis direction so that its measurement range 31 includes gear 100 and reference jig 101a. Similarly, optical sensor 202 is controlled to move in the z-axis direction so that its measurement range 32 includes gear 100 and reference jig 101a.

[0049] <Gear measurement processing> 11 is a flowchart for explaining gear measurement processing according to the second embodiment. In the following explanation, the subject of operation of each step is the controller 104 or the computer 105. If the computer 105 has the function of the controller 104, the subject of operation is the computer 105.

[0050] (i) Step S201 After the user (operator) places and fixes the gear 100 to be measured on the reference jig 101a, the user (operator) inputs an instruction to start measurement using an input device of the computer 105. The controller 104 receives from the computer 105 the command to start measurement, together with information on the movement distance (measurement ranges 31 and 32) of the linear stages 106 and 107 during one measurement process, and initializes the operations of the optical sensors 201 and 202, the rotation stage 102, and the linear stages 106 and 107.

[0051] (ii) Step S202 Controller 104 controls linear motion stages 106 and 107 and optical sensors 201 and 202 to measure the tooth surface of gear 100 and the partial shape of reference jig 101a while linear motion stages 106 and 107 move optical sensors 201 and 202 in a straight line a predetermined distance in the z-axis direction of Fig. 10. The movement distance of linear motion stages 106 and 107 in the z-axis direction corresponds to measurement ranges 31 and 32 (measurement ranges 31 and 32 are the same range). In other words, the optical sensors 201 and 202 are moved using the linear stages 106 and 107 so that, in one measurement operation, data for the heights of the measurement ranges 31 and 32 can be acquired using the line beam 21 to measure the tooth trace T1-R1 of the gear 100 and the vertex V1 of the reference jig 101a and at least a portion of the adjacent sides, and using the line beam 22 to measure the tooth trace T1'-R1' of the gear 100 and the vertex V5 of the reference jig 101a and at least a portion of the adjacent sides.

[0052] The controller 104 sends the data acquired in one measurement process (the measurement data of the reference jig 101a and the measurement data of the gear 100) to the computer 105. The computer 105 stores the received measurement data in a memory (not shown) until all the data has been acquired.

[0053] (iii) Step S203 The computer 105 checks whether the measurement process has been completed for the entire circumference of the gear 100. If measurement data for the entire circumference of the gear 100 has been acquired (Yes in step S203), the process proceeds to step S205. If measurement data for the entire circumference of the gear 100 has not yet been acquired (No in step S203), the process proceeds to step S204.

[0054] (iv) Step S204 In response to a command from the computer 105, the controller 104 controls the rotation stage 102 to rotate the gear 100 and the reference jig 101a by an arbitrary angle around the rotation axis 11. For example, the rotation angle can be set to 360° / N based on the number of teeth N of the gear 100. When the number of teeth N=12, the angle is 360° / 12=30°. By measuring each tooth at a rotation angle of 360° / N, the incidence conditions of the line beams 21 and 22 become the same for all teeth of the gear 100. In other words, the measurement conditions become the same for all teeth of the gear 100.

[0055] As described above, any rotation angle can be used, but by setting the rotation angle to 360° / N, the positional relationship between each tooth of gear 100 and optical sensor 201 or optical sensor 202 can be made reproducible for each measurement, so that the incidence conditions of line beams 21, 22 are the same for all teeth of gear 100. In other words, the optical conditions (measurement conditions) can be made the same for all teeth of gear 100.

[0056] (v) Step S205 When the computer 105 confirms that it has received measurement data for the entire circumference of the gear from the controller 104, it ends the measurement process.

[0057] (vi) Step S106 Computer 105 synthesizes each of the measured partial shapes of gear 100 to obtain (draw) the overall shape of the gear. At this time, the partial shape of reference jig 101a measured simultaneously with gear 100 in step S102 is used as a reference for alignment when synthesizing the overall shape of the gear. The method of synthesizing the overall shape of gear 100 is the same as in the first embodiment, so a description thereof will be omitted.

[0058] <Advantages of the second embodiment> According to the second embodiment, in addition to the above effects (i) and (ii) of the first embodiment, restrictions on the measurement range in the height (tooth trace) direction of the gear 100 are alleviated. For example, even if the thickness (height) of the gear 100 increases, the gear 100 can be measured by adjusting (increasing) the movable range in the z direction of the optical sensors 201 and 202. This is because, while in the first embodiment, the measurement range in the height direction of the gear 100 depends on the spread angle ψ of the line beams 21 and 22, in the second embodiment, measurement is possible within the operating range of the linear stages 106 and 107.

[0059] (3) Variations In the first and second embodiments, the shape measurement process of the external gear has been described, but the shape of the internal gear can also be measured using the technology disclosed herein. More specifically, when measuring the shape of the internal gear, the angles of the optical sensors 201 and 202 with respect to the xy plane can be adjusted to an angle that allows light to be irradiated onto both the reference jig 101 or 101a and the internal gear, thereby making it possible to apply the all-around shape synthesis process described above.

[0060] (4) Summary (i) According to the technique of the present disclosure, the gear 100 to be measured is placed on the reference jig 101 or 101a whose contour shape is known, and measurement is performed by irradiating light onto the reference jig 101 and the gear 100 using at least one optical sensor 201 or 202. The computer 105 obtains the shape of the gear by applying alignment data of the measurement data of the reference jig to the data of the known contour shape of the gear. The gear mounting surface 108 of the reference jig is preferably larger than a circle defined by the outer diameter of the gear. The shape of the gear mounting surface 108 of the reference jig 101 or 101a can be a regular polygon with the same number of vertices as the number of teeth of the gear 100.

[0061] In this embodiment, the measurement data of the reference jig 101 or 101a, whose contour shape is known, is aligned with the known contour shape data to calculate the deviation of the measurement data of the reference jig 101 or 101a from the known contour shape data (the amount of parallel movement and rotational movement on the calculation coordinates: coordinate transformation values), and this is applied to the measurement data of the gear 100. Therefore, even if the position of the gear 100 placed on the reference jig 101 or 101a is slightly misaligned, it is possible to accurately synthesize the entire circumference shape of the gear 100.

[0062] (ii) In the shape measurement system 1 or 1A according to the present embodiment, as in the prior art, a rotating stage (including a rotary encoder) 102 on which the reference jig 101 or 101a is placed and which rotates the gear 100 and the reference jig 101 or 101a can be used. In this case, the computer 105 rotates the rotating stage 102 by an arbitrary angle and operates the optical sensors 201 and 202 to obtain one measurement data of the reference jig 101 or 101a and the gear 100, and repeats the rotation by an arbitrary angle and the measurement operation by the optical sensors 201 and 202 to obtain measurement data of the entire circumference of the reference jig 101 or 101a and the gear 100. The computer 105 then applies alignment data (amount of translation and amount of rotation on the calculation coordinate system: coordinate transformation value) of the measurement data of the entire circumference of the reference jig 101 or 101a with respect to the data of the known contour shape to the measurement data of the entire circumference of the gear 100 to obtain the entire circumference shape of the gear 100. In this way, the measurement data of reference jig 101 or 101a is used for alignment, so even if a rotary stage 102 and a rotary encoder are used, it is possible to eliminate the adverse effect on the synthesis accuracy of the gear's overall shape caused by the angular error of the rotary encoder. This makes it possible to evaluate the gear's overall shape with high accuracy, regardless of the size of gear 100.

[0063] (iii) In the shape measurement system 1 or 1A according to the present embodiment, the rotation stage 102 and the linear motion stages 103, 106, and 107 for relatively linearly moving the optical sensors 201 and 202 and the reference jig 101 or 101a on which the gear 100 is placed, in a direction perpendicular to the optical axis of the light from the optical sensors 201 and 202, can be used. In this case, the computer 105 operates the optical sensors 201 and 202 while linearly moving the linear motion stages 103, 106, and 107, to obtain measurement data of a part of the gear 100 and a part of the reference jig 101 or 101a, and then rotates the rotation stage 102 by an arbitrary angle to change the measurement location. The computer 105 then repeats obtaining local measurement data and changing the measurement location by rotation to obtain measurement data of the entire circumference of the gear 100 and the reference jig 101 or 101a. Once the measurement data for the entire circumference has been acquired, computer 105 acquires the entire circumference shape of gear 100 by applying alignment data (amounts of translation and rotation on the calculation coordinates: coordinate transformation values) for the known contour shape data of the measurement data for the entire circumference of reference jig 101 or 101a to the measurement data for the entire circumference of gear 100. Since the gear 100 or optical sensors 201 and 202 are thus moved in a straight line to measure the three-dimensional shape, the measurement accuracy depends on the accuracy of optical sensors 201 and 202 and linear stages 103 or 106 and 107, and does not depend on the diameter of gear 100. In other words, it is possible to measure the tooth profile and tooth trace with high accuracy regardless of the gear size.

[0064] In the first embodiment, linear motion stage 103 linearly moves reference jig 101, on which gear 100 is placed, in a direction (y-axis direction) parallel to gear placement surface 108 of reference jig 101. Light emitted by optical sensors 201 and 202 is configured to have a spread of a predetermined angle φ in the movement direction of linear motion stage 103 (y-axis direction).

[0065] In the second embodiment, the linear motion stages 106 and 107 move the optical sensors 201 and 202 linearly in the height direction (z-axis direction) of the reference jig 101a and the gear 100. The light emitted by the optical sensors 201 and 202 is configured to have a spread of a predetermined angle ψ in the movement direction of the linear motion stages 106 and 107.

[0066] (iv) The functions of the present embodiment can also be realized by software program code. In this case, a storage medium on which the program code is recorded is provided to a system or device, and the computer (or CPU or MPU) of the system or device reads the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-mentioned embodiment, and the program code itself and the storage medium on which it is stored constitute the present disclosure. Examples of storage media for supplying such program code include flexible disks, CD-ROMs, DVD-ROMs, hard disks, optical disks, magneto-optical disks, CD-Rs, magnetic tapes, non-volatile memory cards, and ROMs.

[0067] Also, an operating system (OS) running on a computer may perform all or a part of the actual processing based on the instructions of the program code, and the functions of the above-mentioned embodiments may be realized by the processing. Furthermore, after the program code read from a storage medium is written into a memory on a computer, a CPU of the computer may perform all or a part of the actual processing based on the instructions of the program code, and the functions of the above-mentioned embodiments may be realized by the processing.

[0068] Furthermore, the program code of the software that realizes the functions of the embodiments may be distributed over a network and stored in a storage means such as a hard disk or memory of the system or device, or in a storage medium such as a CD-RW or CD-R, so that when used, the computer (or CPU or MPU) of the system or device reads out and executes the program code stored in the storage means or storage medium.

[0069] The processes and techniques described herein are not inherently related to any particular apparatus, but may be implemented by any suitable combination of components. Furthermore, various types of general-purpose devices may be used. A dedicated apparatus may be constructed to perform the steps of the methods described herein. Furthermore, various inventions may be formed by suitable combinations of multiple components disclosed in the embodiments. For example, some components may be omitted from all components shown in the embodiments. Furthermore, components across different embodiments may be appropriately combined. Although the present disclosure has been described with reference to specific examples, these are in all respects illustrative and not limiting. Those skilled in the art will recognize that there are numerous combinations of hardware, software, and firmware suitable for implementing the present disclosure. For example, the described software may be implemented in a wide range of program or script languages, such as assembler, C / C++, perl, Shell, PHP, Java (registered trademark), etc.

[0070] Furthermore, in the above-described embodiment, the control lines and information lines are those that are considered necessary for the explanation, and not all of the control lines and information lines in the product are necessarily shown. All of the components may be connected to each other.

[0071] Additionally, other implementations of the present disclosure will be apparent to those of ordinary skill in the art from consideration of the specification and embodiments of the present disclosure disclosed herein. The specification and examples are exemplary only, with the scope and spirit of the present disclosure being indicated by the following claims. [Explanation of symbols]

[0072] 1. 1A Shape Measurement System 11 Rotation axis 100 Gears 101, 101a Reference fixture 102 Rotating Stage 103, 106, 107 Linear stage 104 Controller 105 Computer 108 Gear mounting surface 201, 202 Optical sensor 21, 22 Line beam 21a, 22a Line beam optical axis 301, 301' Partial measurement shape of standard jig 401, 401' Gear Partial Measurement Shape

Claims

1. A shape measurement system for measuring a shape of a gear, comprising: a reference jig having a gear mounting surface on which the gear to be measured is mounted; At least one optical sensor that irradiates light onto the reference jig and the gear to perform measurements; a linear motion stage that moves the reference jig and the gear linearly in a direction along the gear mounting surface; a controller that outputs a measurement result of the gear profile based on measurement data by the at least one optical sensor; the linear motion stage and the at least one optical sensor are configured such that, when the reference jig and the gear move linearly on the linear motion stage, light from the optical sensor is irradiated across the reference jig and the gear with the gear mounting surface therebetween, A shape measurement system in which the controller obtains the shape of the gear by applying alignment data for data of a known contour shape of the measurement data of the reference jig to the measurement data of the gear.

2. In claim 1, a diameter of a circle defined by an outer diameter of the gear mounting surface of the reference jig; and The difference in diameter of the circle defined by the outer diameter of the gear is A shape measurement system that is below the measurement range of the optical sensor.

3. In claim 1, a rotation stage on which the reference jig is placed and which rotates the gear and the reference jig; The controller: a process of acquiring one measurement data set of the reference jig and the gear by rotating the rotation stage by an arbitrary angle and operating the optical sensor; a process of repeating the rotation by the arbitrary angle and the measurement operation by the optical sensor to obtain measurement data of the entire circumference of the reference jig and the gear; a process of acquiring a circumferential shape of the gear by applying alignment data of the measurement data of the circumferential circumference of the reference jig with respect to the data of the known contour shape to the measurement data of the circumferential circumference of the gear; A shape measurement system that performs the above.

4. In claim 1, a rotation stage on which the reference jig is placed and which rotates the gear and the reference jig; the linear motion stage is configured to relatively linearly move the reference jig, on which the gear is placed, and the optical sensor in a direction perpendicular to an optical axis of the light from the optical sensor, The controller: a process of acquiring measurement data of a portion of the gear and a portion of the reference jig by operating the optical sensor while moving the linear motion stage linearly; A process of changing a measurement location by rotating the rotation stage by an arbitrary angle; a process of acquiring measurement data of the entire circumference of the gear and the reference jig by repeating the process of acquiring the measurement data and the process of changing the measurement location; a process of acquiring a circumferential shape of the gear by applying alignment data of the measurement data of the circumferential circumference of the reference jig with respect to the data of the known contour shape to the measurement data of the circumferential circumference of the gear; A shape measurement system that performs the above.

5. In claim 4, the linear motion stage linearly moves the reference jig on which the gear is mounted in a direction parallel to the gear mounting surface of the reference jig, A shape measurement system, wherein the light emitted by the optical sensor has a spread at a predetermined angle in the movement direction of the linear stage.

6. In claim 4, the linear motion stage linearly moves the optical sensor in a height direction of the reference jig and the gear; A shape measurement system, wherein the light emitted by the optical sensor has a spread at a predetermined angle in the movement direction of the linear stage.

7. In claim 2, a shape of the gear mounting surface of the reference jig is a regular polygon having the same number of vertices as the number of teeth of the gear.

8. A shape measurement method for measuring a shape of a gear, comprising the steps of: placing the gear to be measured on a reference jig having a known contour shape; using at least one optical sensor to irradiate light onto the reference jig and the gear to perform measurements; and generating, using a controller, measurements of the gear profile based on measurement data from the at least one optical sensor; while the reference jig and the gear are moving linearly on a linear stage which moves the gear linearly, light from the optical sensor is irradiated across the reference jig and the gear via a gear mounting surface on which the gear is mounted, A shape measurement method in which, in the step of generating measurement results of the gear shape, the controller obtains the gear shape by applying alignment data for data of a known contour shape of the measurement data of the reference jig to the measurement data of the gear.

9. In claim 8, further comprising: a step of acquiring measurement data of a part of the gear and a part of the reference jig by operating the optical sensor while linearly moving a linear motion stage that relatively moves the optical sensor and the reference jig, on which the gear is placed, in a direction perpendicular to the optical axis of the light from the optical sensor; a step of rotating a rotation stage on which the reference jig is placed and which rotates the gear and the reference jig by an arbitrary angle to change a measurement location; and repeating the acquisition of the measurement data and changing the measurement location to acquire measurement data of the entire circumference of the gear and the reference jig, The controller obtains the overall shape of the gear by applying alignment data of the measurement data of the entire circumference of the reference jig with respect to the data of the known contour shape to the measurement data of the entire circumference of the gear.

10. In claim 9, In the step of acquiring measurement data of a part of the gear and a part of the reference jig, the controller controls the linear motion stage to linearly move the reference jig on which the gear is mounted in a direction parallel to the gear mounting surface of the reference jig; A shape measuring method, wherein the light emitted by the optical sensor has a spread at a predetermined angle in the movement direction of the linear stage.

11. In claim 9, In the step of acquiring measurement data of a portion of the gear and a portion of the reference jig, the controller controls the linear motion stage to linearly move the optical sensor in a height direction of the reference jig and the gear; A shape measuring method, wherein the light emitted by the optical sensor has a spread at a predetermined angle in the movement direction of the linear stage.

Images