Method and coordinate measuring machine
Patent Information
- Application Number
- JP2023010186
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-01-28
- Filing Date
- 2023-01-26
- Publication Date
- 2025-10-24
AI Technical Summary
Existing methods for measuring gear tooth geometry using tactile scanning are inefficient due to long measurement times and the need for repeated screwing and unscrewing of the measuring probe, while optical sensors require prepositioning and axis accelerations that increase wear and reduce measurement efficiency.
A method and coordinate measuring machine that utilize a first and second sensor to measure geometric features, where the second measurement is performed without prepositioning based on the axial position from the first measurement, allowing for a virtual setting of the measurement start and reducing axis accelerations, thereby shortening the measurement process and minimizing wear.
This approach ensures numerically stable and repeatable evaluations by starting measurements at a consistent point, such as the tooth head, reducing the need for prepositioning and axis accelerations, thus enhancing measurement efficiency and reducing wear on the machine.
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
Technical Field
[0001] The subject matter of the present invention is a method for measuring components and a coordinate measuring machine for performing such a method.
Background Art
[0002] Gears are often measured on a coordinate measuring machine by tactile, i.e., mechanical scanning. Tactile measurement methods are very accurate but have the disadvantage of long measurement times. The measurement probe for scanning the gear must therefore engage with the tooth flanks to be scanned by screwing into each gap between the teeth of the gear and then retreat from the gap again after scanning the tooth flanks. The measurement probe is then screwed into the gap of the next tooth to be measured and this procedure is repeated.
[0003] In order to measure the geometry of the teeth of a gear, the performance of sensors that measure optically only, i.e., non-contact, has been significantly improved in recent years. Coordinate measuring machines for measuring the teeth of a gear are therefore increasingly having an optical sensor used instead of or in addition to a tactile measurement probe. Examples of optical sensors with respect to metrological methods are cameras, laser triangulation systems, interference systems, confocal systems or confocal chromatic systems, linear light projection systems, or focus variation.
Summary of the Invention
Problems to be Solved by the Invention
[0004] If the geometric features of a toothed component have already been determined by a sensor, a further sensor can be pre-positioned for further measurement based on the known measurement data before the further sensor starts the measurement. In this case, it is disadvantageous that the pre-positioning requires acceleration and deceleration of the further sensor and / or the toothed component before the actual measurement is carried out by an updated start of the machine axes and the acceleration updated for that purpose.
[0005] Against this backdrop, the present invention is based on the technical problem of identifying a method and coordinate measuring machine that enable more efficient measurement of toothed components. [Means for solving the problem]
[0006] The above technical problems are achieved in each case by the independent claims. Further embodiments of the present invention arise from the dependent claims and the following description.
[0007] According to a first aspect, the present invention relates to a method comprising: a method step of providing a toothed part on a coordinate measuring machine, wherein the coordinate measuring machine has a first sensor for measuring the geometric features of the toothed part, a second sensor for measuring the geometric features of the toothed part, and a motion axis for performing a measurement operation to acquire measurements of the toothed part; a method step of first measuring geometric features of the toothed part, such as tooth pitch, tooth surface flank line, tooth surface contour line, etc., using the first and / or second sensors, wherein a first relative measurement operation is performed to move along a first measurement path to acquire one or more first measurements to determine the geometric features; and a method step of second measuring geometric features of the toothed part, such as tooth pitch, tooth surface flank line, tooth surface contour line, etc., using the first and / or second sensors, wherein a second relative measurement operation is performed to move along a second measurement path to acquire second measurements to determine the geometric features. The method is distinguished in that the evaluation of the second measurement is performed taking into account the axis position known from the first measurement.
[0008] Considering the axial position in the context of this evaluation allows for the evaluation of measurements to always be performed using a comparable measurement start point, ensuring, for example, that the evaluation of the measurement always starts at the tooth head of the toothed component being measured, thus enabling a numerically stable and repeatable evaluation of the results.
[0009] When referring to the axis position in this application, this is not a measurement obtained with a toothed component in this case, but rather the position of the mechanical axis of the coordinate measuring machine.
[0010] When a measurement value is referred to in this application, in this case it is a measurement value taken on a toothed part, which is calculated from the sensor value of a first or second sensor and the axial position of the mechanical axis of a coordinate measuring machine. Such a sensor value may be, for example, the measured deflection of a tactile measuring probe experienced as a result of the measuring probe contacting the surface of the toothed part. Such a sensor value may be, for example, the measured distance of a light sensor with respect to a focal point on the surface of the toothed part.
[0011] Prior to the second measurement, the pre-positioning of the second sensor on the toothed component may not be performed based on measurements known from the first measurement. In this way, pre-positioning and updated start are not performed for the measurement, and instead only a measurement operation having an acceleration procedure at the start of the measurement and a deceleration procedure at the end of the measurement is performed, thus reducing the number of acceleration procedures required for the second measurement. The pre-positioning and deceleration can therefore be omitted. Since less axial acceleration is required for each measurement procedure, the measurement procedure can be shortened in this way, and wear on the coordinate measuring machine can be reduced.
[0012] According to one embodiment of this method, for the evaluation of the second measurement, the sequence of the second measurement may be determined based on the axis position. For example, the rotation angle of the rotation axis of the coordinate measuring machine and / or the axis position of the linear axis may be assigned to each measurement, and the evaluation sequence can be performed, for example, according to the increase or decrease of the assigned rotation angle and / or according to the increase or decrease of the assigned axis position.
[0013] Alternatively or additionally, one of the second measurements may be defined as the starting point for evaluating the second measurement based on the axial position. In particular, for example, one of the second measurements may be selected as the starting point from among those known based on the axial position from the first measurement which is on the tooth head of the toothed part.
[0014] Alternatively or additionally, in an axial position-based evaluation, it may be confirmed that some of the second measurements are not required to determine geometric features in relation to the second measurements. Thus, for example, the initial measurement of the second measurement may not be evaluated, discarded, or used as a starting point for evaluation. In particular, for example, some of the initial measurements of the second measurement may not be evaluated, discarded, or used as a starting point for evaluation that is not at the tooth head of the toothed part, so that it can be ensured that the evaluation starts from the measurement at the tooth head of the toothed part.
[0015] In the evaluation, a virtual setting of the relationship between the measured values of the second measurement and the toothed component may be made to determine an appropriate starting point for the evaluation. The virtual setting of the relationship may correspond to a shift and / or rotation of the coordinate system of the measurement and filtering of the second measured value at the starting point of the evaluation.
[0016] In particular, the virtual setting of the relationship between the measured values of the second measurement to the toothed part performed in the evaluation may be defined in the evaluation as, for example, one of the second measured values being at the tooth head of the toothed part as the starting point for the evaluation of the second measurement, and the evaluation being performed, for example, according to the increase in an assigned rotation angle, i.e., in a predetermined rotation direction. The virtual setting of the relationship thus enables the evaluation of the measured values of the second measurement to be carried out in an accurate, repeatable, and reproducible manner, and in particular enables the numerical stability of the evaluation to be ensured.
[0017] The second measurement pass may have a length greater than the minimum length required to determine the geometric features determined by the second measurement. For example, if a 360-degree part rotation is required, or if the measurement needs to be taken over a 360-degree angle to measure the geometric features to be determined, the second measurement pass may have a part rotation exceeding 360 degrees, or the measurement may be taken over an angular range exceeding 360 degrees. In particular, in this way, a virtual setting of the relationship may be possible in the context of this evaluation, in that the measurement taken up to a suitable starting point for evaluation is taken but not used as the starting point for evaluation.
[0018] Alternatively or additionally, the second measurement pass may have a first pass portion and a second pass portion, such that additional measurements not required to determine the geometric features of the toothed part to be determined by the second measurement are taken along the first pass portion, and a second measurement required to determine the geometric features of the toothed part is taken along the second pass portion.
[0019] According to one embodiment of this method, the angle increment and / or path increment may be determined from the axis position, and these may define the distance of the sensor used for the second measurement with respect to the geometric reference variables of the part suitable as the starting point for evaluation of the tooth head, etc.
[0020] To define a second measurement path, angle increments and / or path increments may be added to the minimum measurement path required to obtain the geometric features of the toothed part to be determined by the second measurement. The minimum measurement path required to obtain the geometric features of the toothed part to be determined by the second measurement is therefore supplemented or extended in particular by angle increments and / or path increments to enable, in the context of this evaluation, a virtual setting of the relationship of the measurements of the second measurement to the toothed part.
[0021] According to one embodiment of the present method, the angular increment and / or the path increment may be pre-fixed to the measurement path that is minimally required to determine the geometric features of the toothed component to be determined by the second measurement, so as to enable virtual setting of the relationship of the measured value of the second measurement to the toothed component in the context of this evaluation.
[0022] The second measurement values obtained along the angular increment and / or the path increment may not be defined as the starting point of the evaluation and / or may not be evaluated to determine the geometric features of the second measurement.
[0023] According to one embodiment of the present method, the axial position may have items of information regarding the relative position and / or orientation of the gear related to the sensor used in the second measurement.
[0024] The second sensor may be an optical sensor.
[0025] According to one embodiment of the present method, the axial position may have items of information regarding the relative angular position of the optical axis of the second sensor with respect to a reference point, reference line, or reference plane of the toothed component, such as the tooth tip, tooth root, tooth tip, flank line, contour line, middle part of the tooth tip, middle part of the tooth root, middle part of the tooth surface, etc.
[0026] The first sensor may be a tactile sensor such as a measurement probe having a ball tip, etc. The tactile sensor may be a switching or scanning measurement probe.
[0027] According to one embodiment of the present method, the first measurement may be tactilely performed by a tactile sensor, and the second measurement may be optically performed by an optical sensor.
[0028] The movement along the second measurement path may include a rotation of more than 360 degrees around the self-axis of the toothed component with respect to the sensor used in the second measurement.
[0029] The movement along the second measurement path by the machine axes of the coordinate measuring machine consists only of the component rotation of the components in front of the optical sensor, and the optical sensor may be stationary during measurement and not move during measurement.
[0030] The movement along the second measurement path by the machine axes of the coordinate measuring machine includes the component rotation of the components in front of the optical sensor, and the optical sensor may be moved translationally during measurement.
[0031] According to a second aspect, the present invention relates to a coordinate measuring machine configured to execute the method according to the present invention. The coordinate measuring machine may be only a measuring device provided and suitable only for the measurement task. The coordinate measuring machine may be a part integrated with a machine tool configured for cutting a toothed part.
Brief Description of the Drawings
[0032] The present invention will be described in more detail below based on the drawings showing exemplary embodiments. [Figure 1] FIG. 1 shows a coordinate measuring machine according to the present invention. [Figure 2] FIG. 2 shows a gear together with a tactile measurement system. [Figure 3] FIG. 3 shows the gear of FIG. 2 together with an optical measurement system. [Figure 4] FIG. 4 shows a flowchart of the method according to the present invention.
Embodiments for Carrying Out the Invention
[0033] FIG. 1 shows a coordinate measuring machine 2 according to the present invention configured to execute the method according to the present invention. The coordinate measuring machine 2 has a first sensor 4, which is a tactile sensor 4 for measuring the teeth of a gear and is a measuring probe having a ball tip 5 in this case. The coordinate measuring machine 2 has a second sensor 6, which is an optical sensor for measuring the teeth of a gear. In this case, the optical sensor 6 is a confocal chromatic distance sensor.
[0034] The coordinate measuring machine 2 has a control and evaluation unit 8 configured to control the relative measurement operation between sensors 4 and 6 and the toothed component 10 to be measured. In this case, the toothed component 10 is a gear. Furthermore, the control and evaluation unit 8 is used to evaluate the measurements obtained by sensors 4 and 6.
[0035] The coordinate measuring machine 2 has a turntable 11, which can rotate the gear 10 around axis C. The coordinate measuring machine 2 further has a linear drive device that translates sensors 4 and 6 along the x, y, and z axes of the Cartesian coordinates and performs relative measurement operations with respect to the gear 10.
[0036] In step (A) of the method according to the present invention, the gear 10 is supplied to the coordinate measuring machine 2.
[0037] In method step (B), a first measurement of the geometric features of the gear 10 is subsequently performed by the first sensor 4, as shown as an example in Figure 2. Here, for example, the contour line along the measurement path 12 and / or the flank line along the measurement path 14 are measured as geometric features of the gear 10. The measured geometry of the gear 10 is a three-dimensional measurement in space, but is calculated from the sensor value of the first sensor 4 and the axis position of the coordinate measuring machine 2, so the position and orientation of the gear 10 relative to the optical sensor 6 are known from the first measurement.
[0038] In method step (C), a second measurement of the geometric features of the toothed part 10 is subsequently performed by the second sensor 6, and a second relative measurement operation is performed so as to move along the second measurement path 16, and the second measurement is required to determine the geometric features.
[0039] The second measurement pass 16 includes a 360-degree rotation of the gear 10 and an additional angle increment 18, the angle increment 18 being fixed in advance as a supplement to the 360-degree rotation.
[0040] In step (D) of the method, the second measurement is evaluated, taking into account the axis position known from the first measurement.
[0041] In this case, the measurements obtained along the angle increment 18 during the second measurement are not used to evaluate the geometric characteristics of gear 2 obtained by the second measurement.
[0042] Prior to the second measurement, no pre-positioning of the second sensor 6 on the toothed component 10 based on the measurements from the first measurement is performed. Instead, a virtual setting of the relationship between the measurements of the second measurement and the toothed component 10 is performed in the evaluation. In this evaluation, the measurements taken along the angle increment 18 are not defined as the starting point for the evaluation of the second measurement. Rather, the first measurement among the second measurements following these measurements at the angle increment 18 is defined as the starting point for the evaluation of the second measurement.
[0043] In the evaluation, a virtual setting of the relationship between the measurements of the second measurement and the toothed part 10 is performed, in such a way that the measurements taken along the angle increment 18 are not defined as the starting point for the evaluation of the second measurement, but rather the first measurement among the second measurements following these measurements of the angle increment 18 is defined as the starting point for the evaluation of the second measurement.
[0044] In particular, the evaluation may begin from this starting value, which increases according to the angle of the C-axis position assigned to the measurement.
[0045] In this way, it can be ensured that the evaluation of the second measurement for each toothed component 10 always starts, for example, at the tooth head 20. For this purpose, the axis position has an item of information relating to the relative angular position of the optical axis 22 of the second sensor 6 with respect to the center 24 of the tooth head 20, for example, in order to enable a virtual setting of the relationship or to calculate the angular increment 18.
[0046] The second measurement path 16, therefore, has a length greater than the minimum length required to determine the geometric features determined by the second measurement, since the pre-positioning of the second sensor 6 is omitted. [Explanation of Symbols]
[0047] 2. Coordinate measuring machine 4. Tactile sensors 5 Ball tip 6. Light sensor 8. Control and Evaluation Unit 10 gears 11 Turntable 12 measurement paths 14 measurement paths 16 measurement paths 18 Angle increment 20 tooth heads 22 Optical axis 24 Center of the tooth crown
Claims
1. providing a toothed part (10) on a coordinate measuring machine (2), said coordinate measuring machine (2) having a first sensor (4) for measuring a geometric feature of said toothed part (10), having a second sensor (6) for measuring a geometric feature of said toothed part (10), and having a motion axis for performing a measurement operation to obtain measurements on said toothed part (10); a first measurement of a geometric feature of the toothed component (10), such as a tooth pitch, a tooth flank line, or a tooth flank profile line, by the first sensor (4) and / or the second sensor (6), wherein a first relative measurement operation is performed to move along a first measurement path (12, 14), and one or more first measurement values are obtained to determine the geometric feature; a second measurement of a geometric feature of the toothed component (10), such as a tooth pitch, a tooth flank line, a tooth flank profile line, etc., by the first sensor (4) and / or the second sensor (6), wherein a second relative measurement operation is performed to move along a second measurement path (16), and second measurements are taken to determine the geometric feature; It has A method, wherein the evaluation of the second measurement is performed taking into account the axial position known from the first measurement.
2. the second measurement is not preceded by a pre-positioning of the second sensor relative to the toothed component (10) based on measurements known from the first measurement. The method of claim 1.
3. a sequence of second measurements for the evaluation of the second measurements is determined based on the axial position; and / or a measurement of the second measurements is defined as a starting point for the evaluation of the second measurements based on the axis position; and / or determining, based on the axis positions in the evaluation, that some of the second measurements are not required to determine a geometric feature responsive to the second measurements; and / or a virtual setting of the relationship of the measured value of the second measurement to the toothed component (10) is carried out in the evaluation; 3. The method according to claim 1 or 2.
4. the second measurement path (16) has a length greater than the minimum length required to determine the geometric feature to be determined by the second measurement; the second measurement path (16) has a first path portion and a second path portion, along which further measurements are taken that are not required to determine the geometric feature of the toothed component (10) to be determined by the second measurement, and along which second measurements are taken that are required to determine the geometric feature of the toothed component (10).
3. The method according to claim 1 or 2.
5. an angle increment and / or a path increment is determined from the axial position and defines the distance of the first sensor (4) and / or the second sensor (6) used for the second measurement relative to a geometric reference of the toothed component (10) suitable as an evaluation start point; 3. The method according to claim 1 or 2.
6. the angular increment and / or path increment is added to a measurement path minimally required to obtain the geometric feature of the toothed component (10) determined by the second measurement to define the second measurement path (16). The method of claim 5.
7. the angular increment and / or path increment is pre-fixed to a measurement path (16) minimally required to determine the geometric feature of the toothed component determined by the second measurement. The method of claim 6.
8. a second measurement taken along the angle increment and / or the path increment is not defined as a starting point for the evaluation and / or is not evaluated to determine the geometric characteristics of the second measurement; The method of claim 5.
9. the axial position comprises an item of information about the relative position and / or orientation of the toothed component (10) in relation to the first or second sensor (4, 6) performing the second measurement; 3. The method according to claim 1 or 2.
10. The second sensor (6) is an optical sensor (6).
3. The method according to claim 1 or 2.
11. said axial position comprising an item of information about the relative angular position of the optical axis (22) of said second sensor (6) in relation to a reference point, line or surface of said toothed part, such as the head, root, tip, flank line, profile line, center of head, center of root, center of flank, etc.
10. The method of claim 9.
12. The first sensor (4) is a tactile sensor (4) such as a measurement probe having a ball tip or the like.
3. The method according to claim 1 or 2.
13. The first measurement is performed tactilely by a tactile sensor (4) and the second measurement is performed optically by an optical sensor (6).
3. The method according to claim 1 or 2.
14. the movement along the second measurement path (16) includes a rotation of more than 360 degrees about its own axis relative to the first sensor (4) and / or the second sensor (6) performing the second measurement.
3. The method according to claim 1 or 2.
15. A coordinate measuring machine configured to perform the method of claim 1 or 2.