A method for tracing the quantitative values ​​of involutes with large base circle radii

Abstract

This invention belongs to the field of precision gear measurement technology, specifically relating to a method for tracing the measurement values ​​of involutes with large base circle radii. The method includes the following steps: Step 1, determining the coordinate system and measurement transfer parameters for measurement value tracing; Step 2, adjusting the pose of the involute template; Step 3, adjusting the position of the involute template; Step 4, calibrating the involute parameters; Step 5, eliminating coordinate system establishment errors to calibrate the measuring instrument. The method provided by this invention fills the gap in measurement value tracing methods for large-size gears with diameters greater than 500 mm. It can effectively identify the impact of coordinate system establishment errors on the accuracy of gear profile measurement, improve the applicability of large gear measuring instruments in complex environments such as on-machine measurement, achieve high-precision measurement of involutes, is simple and easy to implement, has high measurement accuracy, is convenient for transportation and installation adjustment, and has good market application prospects and promotional value.

Description

Technical Field

[0001] This invention belongs to the field of precision gear measurement technology, specifically relating to a method for tracing the measurement value of an involute curve with a large base circle radius. Background Technology

[0002] Large gears generally refer to gears with a diameter greater than 500mm. Gears with a diameter between 500 and 3000mm are called large gears, and those with a diameter greater than 3000mm are called extra-large gears. Large and extra-large gears are widely used in shipbuilding, heavy-duty helicopters, and new energy equipment. Compared with general gear transmission devices, these gear transmission devices are characterized by high power (50MW and above per shaft), large size (gear diameter 3-5m), large mass (single unit up to tens of tons), high gear precision (3-5 grades), long service life, and complex structure. However, precise control of tooth surface profile, improvement of manufacturing accuracy, reduction of vibration and noise, and improvement of power density all require precision measurement technology for large gears. The key to achieving precision measurement of large gears is ensuring the measurement accuracy of the large gear measuring instruments.

[0003] For the calibration of the measurement accuracy of large gear measuring instruments, the involute template verified by the National Institute of Metrology is generally used to measure the tooth profile. The instrument reading is then corrected by comparing the template value with the parameter verification value, thus achieving traceability of the tooth profile measurement results of the large gear measuring instrument.

[0004] Dalian University of Technology, Kyoto University, and the National Institute of Metrology of Japan have developed a dual-roller laser measurement device for involute references based on a pure rolling generating method. This device uses a laser interferometer to directly measure involute templates with a base disk, achieving high-precision measurement of involutes with U(Fα,fHα,ffα) < 0.5 μm. However, this method is limited by the size of the rollers and can only be used for the traceability of involute tooth profiles with small to medium base circle parameters of specific specifications; it cannot be used for the traceability of large gears with diameters greater than 500 mm.

[0005] To achieve traceability of the measurement values ​​of involute tooth profiles with large base circle radii, PTB in Germany built a 5m×4m×2m coordinate measuring machine and incorporated it into the length traceability chain. They also developed a calibration program for 3D measurement of gear templates. This measurement method obtains the spatial position error mapping of the tooth surface detection points for the tooth profile measurement task through length measurements using multiple laser trackers, thereby correcting the errors of the tooth surface detection points and providing traceability of measurement values ​​based on laser frequency calibration. However, the measurement accuracy of this method is limited, and the measurement results have not yet reached the first-level accuracy evaluation standard for large involute gears.

[0006] The lack of a traceability method for the measurement of involute tooth profiles with large base circle radii has resulted in the absence of a measurement transfer system for large gears. Consequently, the corresponding measuring instruments for large gears cannot be calibrated, and the accuracy of the measurement results for the involute tooth profiles of large gears with diameters greater than 500 mm cannot be verified. Summary of the Invention

[0007] This invention provides a method for tracing the measurement values ​​of involutes with large base circle radii, in order to overcome the problem that existing technologies cannot achieve the measurement value tracing of involute tooth profiles with large base circle radii.

[0008] To achieve the objectives of this invention, the solution provided is: a method for tracing the quantitative values ​​of an involute with a large base circle radius, comprising the following steps:

[0009] Step 1: Determining the coordinate system and measurement transfer parameters for measurement traceability:

[0010] Establish three coordinate systems: the gear workpiece coordinate system, the large gear measuring instrument's measurement coordinate system, and the involute template's design coordinate system;

[0011] Determining the parameters for value transfer: the involute tooth profile cylindrical surface that enables value transfer, and the reference surface used for spatial positioning;

[0012] Step 2: Adjusting the pose of the involute template:

[0013] The involute template, along with the six-degree-of-freedom fine-tuning device, is placed on the upper surface of the gear being tested.

[0014] Step 3: Adjust the position of the involute template:

[0015] The probe of the large gear measuring instrument is used to measure the spatial positioning reference surface of the involute template, and the design coordinate system of the involute template is made to coincide with the measurement coordinate system by fine-tuning the six-degree-of-freedom fine-tuning device.

[0016] Step 4: Involute parameter calibration:

[0017] When performing involute parameter calibration, the involute template rotates with the workpiece coordinate system. The tooth profile deviation measurement method of gear tooth profile is used to measure the tooth profile deviation curve of the involute template. If the calibration standard is met, the calibrated large gear measuring instrument can perform involute tooth profile measurement.

[0018] If the calibration standard is not met, proceed to the next step;

[0019] Step 5: Eliminate coordinate system establishment errors to calibrate measuring instruments.

[0020] By analyzing the tooth profile deviation measurement results F α Identify the coordinate system establishment error (Δx0, Δy0):

[0021] F α =f(Δx0,Δy0)

[0022] The established coordinate system is then corrected to ensure that the measurement coordinate system coincides with the workpiece coordinate system. Steps three and four are then repeated until the calibration standard is met, at which point the involute tooth profile is measured.

[0023] Compared with the prior art, the advantages of the present invention are:

[0024] 1. The method provided by this invention fills the gap in the traceability method for large gears with a diameter greater than 500mm. In the method of this invention, the position of the involute template spans the workpiece coordinate system and the measurement coordinate system. By measuring the involute template, the influence of coordinate system establishment error on the tooth profile measurement accuracy can be effectively identified, thereby effectively overcoming the common problems in high-precision measurement of large gears.

[0025] 2. The method of the present invention can use a template with the same radius as the base circle of the gear being measured to calibrate the measurement system. The calibrated measurement space includes the actual measurement space, which can realize "one-to-one" and "point-to-point" calibration and correction of the large gear measuring equipment on the production site, and improve the applicability of the large gear measuring instrument in complex environments such as on-machine measurement.

[0026] 3. The method of this invention ensures the relative positional relationship between the involute tooth surface and the center of the base circle through measurement and fine-tuning, enabling high-precision measurement of the involute. Because of the method provided by this invention, the corresponding involute template is small in size, avoiding the problem of increased uncertainty in the transfer parameters caused by factors such as temperature and gravity affecting the template's accuracy and stability when using large templates.

[0027] 4. The measurement method provided by this invention is simple and easy to implement, with high measurement accuracy. It can effectively meet the calibration requirements of high-precision large gear measuring instruments and large gear in-machine measurement systems. It is also easy to transport, install and adjust, and has good market application prospects and promotion value. Attached Figure Description

[0028] Figure 1 This is a schematic diagram illustrating the principle of the involute measurement method based on pure rolling generation;

[0029] Figure 2 This is a schematic diagram of the involute template structure used in the embodiments of the present invention;

[0030] Figure 3 yes Figure 2 Axial view along direction A;

[0031] Figure 4 This is a schematic diagram of the method for tracing the magnitude of the involute tooth profile with a large base circle radius.

[0032] The attached figures are labeled as follows:

[0033] 1-Involute tooth profile cylindrical surface; 2-Reference bottom surface; 3-Reference top surface; 4-Tooth root reference surface; 5-Tooth tip reference surface; 6-Rotary worktable; 7-Gear under test; 8-Involute template; 9-Large gear measuring instrument; 10-Six-degree-of-freedom fine-tuning device. Detailed Implementation

[0034] The method of the present invention will now be described in detail with reference to the accompanying drawings.

[0035] See Figure 1 This is the principle of a common pure rolling generating method in existing technology. The roller radius is the same as the base circle radius. When the roller rolls purely on the guide rail, the position of the intersection point P of the standard involute and the generating line (guide rail) does not change. By placing a probe at point P, the involute can be measured. However, this method is limited by the size of the roller and can only be used for the traceability of involute tooth profiles with small to medium base circle parameters of specific specifications.

[0036] A method for tracing the quantitative values ​​of an involute with a large base circle radius specifically includes the following steps:

[0037] Step 1: Determining the coordinate system and measurement transfer parameters for measurement traceability:

[0038] When using templates to calibrate a gear measuring system, the following three coordinate systems are required: the gear workpiece coordinate system, the measuring coordinate system of the large gear measuring instrument 9, and the design coordinate system of the involute template 8.

[0039] The parameters for value transfer are: the involute tooth profile cylinder 1 that can be used for value transfer, and the reference surface used for spatial positioning, and the verification values ​​given by the National Institute of Metrology.

[0040] According to the above requirements, the structure of the involute template 8 provided in this embodiment of the invention is as follows: See Figure 1 and Figure 2 It includes two opposing involute tooth profile cylindrical surfaces 1 for realizing the transfer of measurement values, and reference bottom surfaces 2 and reference top surfaces 3 symmetrically arranged on the upper and lower sides for spatial positioning. Tooth root reference surfaces 4 and tooth tip reference surfaces 5 are arranged parallel on the front and rear sides, and the involute template 8 has the verification value of the National Institute of Metrology.

[0041] Step 2: Adjusting the pose of involute template 8:

[0042] See Figure 4During measurement, the involute template 8, which has been verified by the National Institute of Metrology and has a verification value, is placed together with the six-degree-of-freedom fine-tuning device 10 on the upper surface of the gear 7 being measured. By adjusting the six-degree-of-freedom fine-tuning device 10, the tooth-shaped involute template 8 can rotate slightly around the X, Y, and Z directions and translate along the X, Y, and Z directions.

[0043] Step 3: Adjust the position of involute template 8:

[0044] The probe of the large gear measuring instrument 9 is used to measure the spatial positioning reference surface of the involute template 8, and the design coordinate system of the involute template 8 is made to coincide with the measurement coordinate system by adjusting the six-degree-of-freedom fine-tuning device 10.

[0045] That is, the spatial position of the involute template 8 in the measurement coordinate system is ensured by measuring with the large gear instrument 9. Since the actual position of the involute template 8 is also placed on the rotary table 6, it can rotate with the workpiece around the rotation axis and also exists in the gear workpiece coordinate system. Therefore, the involute template spans two coordinate systems: the measurement coordinate system and the gear workpiece coordinate system.

[0046] Step 4: Involute parameter calibration:

[0047] When performing involute parameter calibration, the involute template 8 rotates with the workpiece coordinate system. The tooth profile deviation measurement method of gear tooth profile is used to measure the tooth profile deviation curve of the involute template 8. If the calibration standard measurement result is consistent with the verification value of the involute template 8, or within the error allowable range of the large gear measuring instrument 9, then the calibrated large gear measuring instrument 9 can perform involute tooth profile measurement.

[0048] If the calibration standard is not met, proceed to the next step.

[0049] Step 5: Eliminate coordinate system establishment errors to calibrate measuring instruments.

[0050] In practical work, workpiece installation eccentricity and instrument geometric errors can be detected and eliminated or corrected through other methods. However, the inconsistency in measurement results is mainly caused by the measurement coordinate system not coinciding with the axis of the rotary table 6. This is also difficult to determine and is common in large gear measuring instruments 9.

[0051] By analyzing the tooth profile deviation measurement results F α Identify the coordinate system establishment error (Δx0, Δy0):

[0052] F α =f(Δx0,Δy0)

[0053] The established coordinate system is corrected until the slope error is equal to the verification value of the involute template 8 or within the allowable range of the instrument error. This indicates that the measuring coordinate system coincides with the workpiece coordinate system and meets the calibration standard. Then, the above steps are repeated to complete the calibration of the large gear measuring instrument 9 before performing involute tooth profile measurement.

[0054] The above description is merely the technical method and implementation method of the present invention. The scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by any person based on the technical solution and inventive concept of the present invention are covered within the scope of protection of the present invention.

Claims

1. A method for tracing the quantitative values ​​of an involute with a large base circle radius, characterized in that: Includes the following steps Step 1: Determining the coordinate system and measurement transfer parameters for measurement traceability: Establish three coordinate systems: the gear workpiece coordinate system, the measurement coordinate system of the large gear measuring instrument (9), and the design coordinate system of the involute template (8); Determination of parameters for value transfer: the involute tooth profile cylindrical surface (1) that can transfer values, and the reference surface used for spatial positioning; Step 2: Adjusting the pose of the involute template (8): Place the involute template (8) together with the six-degree-of-freedom fine-tuning device (10) on the upper surface of the gear (7) being tested; Step 3: Adjust the position of the involute template (8): The probe of the large gear measuring instrument (9) is used to measure the spatial positioning reference surface of the involute template (8), and the design coordinate system of the involute template (8) is made to coincide with the measurement coordinate system by the fine-tuning six-degree-of-freedom fine-tuning device (10). Step 4: Involute parameter calibration: When performing involute parameter calibration, the involute template (8) rotates with the workpiece coordinate system. The tooth profile deviation of the involute template (8) is measured by the gear tooth profile deviation measurement method. If the calibration standard is met, the calibrated large gear measuring instrument (9) can perform involute tooth profile measurement. If the calibration standard is not met, proceed to the next step; Step 5: Eliminate coordinate system establishment errors to calibrate measuring instruments. By analyzing the tooth profile deviation measurement results F α Identify the coordinate system establishment error (Δx0, Δy0): F α =f(Δx0,Δy0) The established coordinate system is then corrected to ensure that the measurement coordinate system coincides with the workpiece coordinate system. Steps three and four are then repeated until the calibration standard is met, at which point the involute tooth profile is measured.

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