Tooth pitch value calibration method, tooth pitch simulation standard and design and preparation method thereof

Abstract

The invention belongs to the technical field of pitch standards. In order to solve the technical problem that traditional pitch templates are difficult to process and manufacture, a pitch value calibration method, a pitch simulation standard and a design and preparation method thereof are provided. A standard with a pitch value can be simulated by a standard sphere. It is assumed that a partial arc of the standard sphere is used to replace the involute profile of a single tooth in a target pitch template. According to the geometric relationship between the horizontal projection circle of the standard sphere and the pitch circle of the target pitch template, the radius of the horizontal projection circle and the distance from the horizontal projection circle to the coordinate origin are calculated as the design radius of the standard sphere and the design distance from the center of the standard sphere to the central axis of a high-precision rotating table respectively; the design pitch angle is simulated by the rotation angle of the high-precision rotating table to obtain a simulated pitch angle; the pitch circle radius of the target pitch template is used as the pitch circle radius of the pitch simulation standard; and the arc length corresponding to the simulated pitch angle on the pitch circle is the pitch.

Description

Technical Field

[0001] The invention belongs to the technical field of pitch standard devices, and in particular relates to a pitch simulation standard device for simulating high-precision standard gears and a design method thereof, and also relates to a pitch value calibration method. Background Art

[0002] The pitch template is a standard device used for high-precision calibration and pitch value transfer of CNC gear measuring instruments, so it is also called a pitch standard. In the prior art, high-precision standard gears are used as traditional pitch templates, which have the following defects: (1) The processing technology of traditional pitch templates is very complicated and the manufacturing price is expensive. Its tooth surface is easily scratched by the probe and is not easy to repair; (2) Traditional pitch templates are difficult to process into large sizes, so the calibration range is limited and it is difficult to meet the requirements of larger gear measurement centers; (3) For high-precision gear measuring instruments, due to the limitation of processing accuracy, the accuracy of traditional pitch templates is often difficult to meet the equipment requirements. Summary of the invention

[0003] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art and to provide a design method for a pitch simulation standard to solve the technical problem that traditional pitch templates are difficult to process and manufacture, and to simulate a standard with pitch values ​​through a standard ball.

[0004] The present invention is achieved through the following technical solution: a design method of a pitch simulation standard comprises the following steps:

[0005] Obtain the parameters of the target pitch template, including pitch circle radius, pressure angle, module and number of teeth;

[0006] Establish the coordinate system O of the target pitch template w X w Y w :The center of the target pitch template is taken as the coordinate origin O w , along two mutually perpendicular radial directions are X w Axis, Y w axis;

[0007] In the coordinate system O of the target pitch template w X w Y w In the following example, it is assumed that the involute profile of a single tooth in the target pitch template is replaced by a partial arc of a standard sphere located on the concave side of the involute of the target pitch template: the intersection of the pitch circle of the target pitch template and the involute is taken as the intersection of the standard sphere in the coordinate system O w X w Y w The tangent point of the horizontal projection circle below;

[0008] According to the geometric relationship between the radius of the horizontal projection circle and the pitch circle radius of the target pitch template, the radius of the horizontal projection circle and the distance from the horizontal projection circle to the coordinate origin are calculated;

[0009] The radius of the horizontal projection circle is used as the design radius of the standard sphere, and the distance from the center of the horizontal projection circle to the coordinate origin is used as the design distance from the center of the standard sphere to the central axis of the high-precision rotating table, thereby obtaining the design parameters of the pitch simulation standard;

[0010] The designed pitch angle is simulated by the rotation angle of the high-precision rotating table to obtain the simulated pitch angle; the designed pitch angle θ′=2π / z, z represents the number of teeth of the target pitch template; the pitch circle radius of the target pitch template is used as the pitch circle radius of the pitch simulation standard; the arc length corresponding to the simulated pitch angle on the pitch circle is the pitch.

[0011] Furthermore, the design radius of the standard sphere, that is, the radius of the horizontal projection circle, is calculated according to the following formula:

[0012]

[0013] The design distance, i.e. the distance from the center of the horizontal projection circle to the coordinate origin, is calculated according to the following formula:

[0014]

[0015] In the formula, r c Represents the design radius of the standard sphere; r f Indicates the pitch circle radius of the target pitch template; r d Indicates the design distance from the center of the standard sphere to the central axis of the high-precision rotating table; l PN Indicates the tooth thickness of the target pitch sample, l PN =π·m n / 2,m n represents the module; α represents the pressure angle of the target pitch sample.

[0016] The present invention also provides a method for preparing a pitch simulation standard, using the design method of the pitch simulation standard of the present invention to obtain the design parameters of the pitch simulation standard; selecting a single standard ball according to the design radius and arranging the relative position of the standard ball and the high-precision rotating table according to the design distance, thereby preparing the pitch simulation standard.

[0017] The invention also provides a tooth pitch simulation standard, which is prepared by the method for preparing the tooth pitch simulation standard of the invention.

[0018] Furthermore, the standard balls are arranged on a high-precision rotating table according to the designed distance.

[0019] Furthermore, the standard ball seat is arranged outside the high-precision rotating table, and the relative position between the standard ball and the high-precision rotating table is determined by the laser optical path.

[0020] Furthermore, the laser interferometer is arranged on a high-precision rotating table, the orthogonal beam splitter prism is arranged in the center of the high-precision rotating table, a total reflection mirror is arranged on the top of the orthogonal beam splitter prism, the standard sphere is fixed outside the high-precision rotating table through a support seat, and a measuring mirror is arranged in the area of ​​the support seat opposite to the orthogonal beam splitter prism; the plane where the reflecting surface of the measuring mirror is located is the tangent plane of the standard sphere;

[0021] The relative position between the standard ball and the high-precision rotating table is determined by the laser optical path: the laser beam emitted by the laser interferometer in the horizontal direction is divided into a horizontal beam and a vertical beam after reaching the orthogonal beam splitter prism; the vertical beam coincides with the central axis of the high-precision rotating table; the vertical beam reaches the total reflection mirror and is reflected back to the orthogonal beam splitter prism, and then reflected back to the laser interferometer by the orthogonal beam splitter prism; the horizontal beam reaches the measuring mirror and is reflected back to the laser interferometer;

[0022] By adjusting the position of the support seat, the distance difference between the two reflected light beams plus the radius of the standard sphere is equal to the designed distance.

[0023] Furthermore, the standard ball is fixed on the support seat by a magnetic positioning device.

[0024] The present invention also provides a pitch value calibration method, which uses a three-coordinate measuring machine to calibrate the pitch value of the pitch simulation standard provided by the present invention:

[0025] Determine the number of rotations n=z-1 of the high-precision rotary table at the same initial position according to the number of teeth z, and use the designed pitch angle as the target angle for each rotation;

[0026] The standard ball at the initial position is sampled, and then the standard ball rotates synchronously with the high-precision rotating table. The standard ball is sampled every time it rotates, and the coordinates of the center of the standard ball at each position are fitted through the sampling points;

[0027] The center coordinates of the pitch simulation standard are fitted through the center coordinates of the standard balls at various positions;

[0028] Calculate the angles between the center coordinates of the pitch simulation standard and the lines connecting the center coordinates of the spheres at two adjacent positions as the simulated pitch angle;

[0029] The arc length corresponding to each simulated pitch angle on the pitch circle is calculated to achieve the calibration of the pitch value.

[0030] Furthermore, the error correction of the tooth pitch value is performed:

[0031] At least two different initial positions are set, and the pitch values ​​corresponding to each simulated pitch angle at each initial position are measured; the i-th pitch value at the j-th initial position is expressed as The instrument measurement error of the i-th tooth pitch value at the j-th initial position is expressed as l represents the theoretical tooth pitch value, l = πm n , thus establishing the error correction matrix M:

[0032]

[0033] Calculate the correction value of each pitch value according to the error correction matrix M:

[0034]

[0035] In the formula, represents the element in the i-th row and j-th column in the error correction matrix M, i∈{1,2,.....,z}, z represents the number of teeth, j∈{1,2,......,N}, N represents the total number of initial positions.

[0036] Compared with the prior art, the beneficial effects of the present invention include:

[0037] 1. The gear simulation standard of the present invention requires only the design radius of the standard sphere and the design distance from the center of the standard sphere to the central axis of the high-precision rotating table. This not only makes the design process simple and efficient, but also the fewer the design parameters, the less the preparation error introduced by the preparation of the standard, which is beneficial to improving the accuracy of the standard.

[0038] 2. The present invention very cleverly simulates the designed pitch angle by the rotation angle of the high-precision rotating table, and then simulates the pitch by the arc length corresponding to the simulated pitch angle on the pitch circle, so it is no longer necessary to process high-precision physical gears to provide the pitch value.

[0039] 3. The preparation method of the pitch simulation standard of the present invention is very simple: the high-precision rotating table can be obtained by purchasing a ready-made product, the standard ball can be obtained by purchasing a ready-made product or processing and manufacturing, and only one standard ball is needed, which greatly saves costs. At the same time, compared with sampling multiple standard balls, it reduces the accumulation of processing errors.

[0040] 4. For the simulation of target gear samples with smaller sizes, the standard device can be placed on a high-precision rotating table; for the simulation of target gear samples with larger sizes, the standard ball seat is placed outside the high-precision rotating table, and the relative position between the standard ball and the high-precision rotating table is determined by the laser optical path. In short, by adjusting the distance between the standard ball and the high-precision selection table, the simulation of the size of the target gear sample can be adjusted.

[0041] 5. Laser interferometer is a high-precision instrument. The distance between the standard ball and the high-precision rotating table determined by the optical path of the laser interferometer has extremely high accuracy and can meet the designed distance.

[0042] 6. The present invention measures the pitch values ​​corresponding to each simulated pitch angle at different initial positions by setting different initial positions, and then calculates the average value. The measurement errors in different directions can offset each other, forming a self-closed loop correction of errors and improving the error level. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a theoretical model diagram for using a partial arc of a standard sphere to replace the involute profile in the design process;

[0044] Figure 2 Schematic diagram of the structure of the pitch simulation standard in Example 1;

[0045] Figure 3 This is a schematic diagram of the deviation of the ball center trajectory from the ideal position caused by the eccentricity of the reference circle center;

[0046] Figure 4 is a schematic diagram of the first initial position;

[0047] Figure 5 is a schematic diagram of a second initial position;

[0048] Figure 6 This is the error level diagram before the pitch value is corrected;

[0049] Figure 7 This is the error level diagram after the pitch value is corrected.

[0050] Figure 8 Schematic diagram of the structure of the pitch simulation standard in Example 2. DETAILED DESCRIPTION

[0051] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0052] A method for designing a pitch simulation standard comprises the following steps:

[0053] Get the parameters of the target pitch template, including the pitch circle radius r f , pressure angle α, modulus m n and the number of teeth z;

[0054] refer to Figure 1 As shown, the coordinate system O of the target pitch template is established. w X w Y w :The center of the target pitch template is taken as the coordinate origin O w , along two mutually perpendicular radial directions are Xw Axis, Y w axis;

[0055] In the coordinate system O of the target pitch template w X w Y w In the following example, it is assumed that the involute profile of a single tooth in the target pitch template is replaced by a partial arc of a standard sphere located on the concave side of the involute of the target pitch template: the intersection point P of the pitch circle of the target pitch template and the involute is taken as the intersection point P of the standard sphere in the coordinate system O. w X w Y w The tangent point of the horizontal projection circle below;

[0056] According to the geometric relationship between the radius of the horizontal projection circle and the pitch circle radius of the target pitch template, the radius of the horizontal projection circle and the distance from the horizontal projection circle to the coordinate origin are calculated;

[0057] The design radius of the standard sphere, that is, the radius of the horizontal projection circle, is calculated according to the following formula:

[0058]

[0059] The design distance, i.e. the distance from the center of the horizontal projection circle to the coordinate origin, is calculated according to the following formula:

[0060]

[0061] In the formula, r c Represents the design radius of the standard sphere; r f Indicates the pitch circle radius of the target pitch template; r d Indicates the design distance from the center of the standard sphere to the central axis of the high-precision rotating table; l PN Indicates the tooth thickness of the target pitch sample, l PN =π·m n / 2,m n represents the module; α represents the pressure angle of the target pitch sample.

[0062] The radius of the horizontal projection circle is taken as the design radius r of the standard sphere. c , the center of the horizontal projection circle is o c To the coordinate origin O w The distance is taken as the design distance r from the center of the standard ball to the center axis of the high-precision rotating table. d , thereby obtaining the design parameters of the pitch simulation standard;

[0063] refer to Figure 2As shown in the figure, the design pitch angle is simulated by the rotation angle θ of the high-precision rotary table to obtain the simulated pitch angle; the design pitch angle θ′=2π / z, z represents the number of teeth of the target pitch template; the pitch circle radius r of the target pitch template f The pitch circle radius is used as the pitch simulation standard; the arc length corresponding to the simulated pitch angle on the pitch circle is the pitch.

[0064] After calculating the design parameters of the pitch simulation standard, a single standard ball is selected or prepared according to the design radius and the design distance r is calculated. d The relative positions of the standard ball and the high-precision rotating table are arranged to prepare a pitch simulation standard.

[0065] The three-coordinate measuring machine is used to calibrate the pitch value of the pitch simulation standard:

[0066] Determine the number of rotations n=z-1 of the high-precision rotary table at the same initial position according to the number of teeth z, and use the designed pitch angle as the target angle for each rotation;

[0067] The standard ball at the initial position is sampled, and then the standard ball rotates synchronously with the high-precision rotating table. The standard ball is sampled every time it rotates, and the coordinates of the center of the standard ball at each position are fitted through the sampling points;

[0068] The center coordinates of the pitch simulation standard are fitted through the center coordinates of the standard balls at various positions;

[0069] Calculate the angles between the center coordinates of the pitch simulation standard and the lines connecting the center coordinates of the spheres at two adjacent positions as the simulated pitch angle;

[0070] The arc length corresponding to each simulated pitch angle on the pitch circle is calculated to achieve the calibration of the pitch value.

[0071] Error correction for the tooth pitch value:

[0072] At least two different initial positions are set, and the pitch values ​​corresponding to each simulated pitch angle at each initial position are measured; the i-th pitch value at the j-th initial position is expressed as The instrument measurement error of the i-th tooth pitch value at the j-th initial position is expressed as The error correction matrix M is thus established:

[0073]

[0074] Each column in the error correction matrix M corresponds to an initial position, and the first column is As the subtrahend, the minuend is taken in the closed loop sequence from the 1st pitch value to the zth pitch value to calculate the difference; the second column is As the subtrahend, the minuend is taken in the closed loop sequence from the zth pitch value to the z-1th pitch value to calculate the difference; the third column is The minuend is taken in the closed-loop sequence from the z-1th pitch value to the z-2th pitch value to calculate the difference; and so on, in the closed loop, according to the symmetry characteristics, the measurement errors in some places are too large, and the errors in other places must be too small, so the errors can be significantly eliminated after accumulation.

[0075] Calculate the correction value of each pitch value according to the error correction matrix:

[0076]

[0077] In the formula, Indicates the correction value of the i-th tooth pitch value; represents the element in the i-th row and j-th column in the error correction matrix M, i∈{1,2,.....,z}, z represents the number of teeth, j∈{1,2,......,N}, N represents the total number of initial positions.

[0078] The standard balls are arranged in different ways according to the size of the target pitch template, which are described below with reference to Embodiment 1 and Embodiment 2 respectively.

[0079] Example 1

[0080] For the simulation of the target pitch sample with a smaller size, the standard ball is arranged on the high-precision rotating table. The standard ball is arranged on the high-precision rotating table according to the designed distance. In order to facilitate the replacement of the standard ball, the standard ball is adsorbed and fixed on the high-precision rotating table by a magnetic positioning device. During the measurement process, the standard ball is subjected to the 360° detection force F' of the instrument probe, which requires the magnetic force F1 to be slightly larger than (F'-G b ) / μ, where G b is the weight of the standard ball, and μ is the friction coefficient of the contact surface between the ball and the magnetic device.

[0081] The principle of the magnetic positioning device refers to the magnetic positioning device in the Chinese patent (CN1096822852B). An electromagnet and a circuit are set in a high-precision rotating table. The current size is changed by adjusting the resistance value of the current limiting resistor, thereby changing the magnetic force size.

[0082] The magnetic positioning device can also be a permanent magnet, with the upper and lower ends of the permanent magnet being N and S poles, and the periphery of the permanent magnet being wrapped by insulating material to prevent a large magnetic adsorption force from being generated on the instrument probe.

[0083] The standard ball is adsorbed and fixed on the high-precision rotating table by a magnetic positioning device. The center of the central cylinder of the high-precision rotating table is selected as the axis line of the pitch simulation standard. The central cylinder of the rotating table itself or other references are selected as the benchmark to avoid the central axis of the pitch simulation standard not coinciding with the axis of the high-precision rotating table itself, so as to more accurately determine the central axis of the pitch simulation standard.

[0084] By adjusting the distance between the center of the standard ball and the axis of the turntable (the distance can be measured by a laser cursor), the pitch circle radius r of the target pitch sample can be simulated. f At the same time, the simulated pitch angle can be controlled by rotating the high-precision rotary table to meet the requirements of different pitch arc lengths.

[0085] In order to simplify the verification process, this embodiment selects the most widely used standard ball in the international standard that can be directly purchased, that is, the standard ball with a diameter of 12.7 mm, and r d =r f , the parameters of the target pitch template are as follows: z = 8, m n =26.87925mm,r f =107.51875mm. The diameter of the standard ball is calibrated to meet the requirement of 12.7±0.0005mm; after testing on a three-dimensional coordinate measuring machine, when the magnet adsorption force is greater than 5.42N, the ball is not affected under 360° force. Table 1 is as follows.

[0086] Table 1 Design parameters of the pitch simulation standard

[0087]

[0088] According to the latest international gear standard ISO1328-1, the pitch measurement error level is evaluated. The single pitch deviation f pT Total pitch deviation grade F pT The calculation formulas are as follows:

[0089]

[0090]

[0091] The tooth pitch simulation standard in this embodiment is traced back to the gear multi-parameter metrology standard device of the China Institute of Metrology. Figure 3 The results of repeated measurements of a single pitch deviation are given. Figure 3It can be seen that the average value of single pitch deviation of the newly developed pitch template is between level 0 and level 1, the repeatability of single pitch deviation is less than 1.5μm, and the cumulative total pitch deviation is 7.0μm, which is greater than level 0 6.9492μm and less than level 1 9.8278μm. This shows that the newly developed pitch simulation standard has reached the level of level 1 pitch template.

[0092] The newly developed pitch simulation standard has an axisymmetric structure and a closed-loop feature. It uses multi-directional self-correction technology to eliminate system errors during use. Figure 4 The scenario in which the spherical center trajectory deviates from the ideal position due to the eccentricity of the reference circle center is given (as shown by the dotted trajectory in the figure). This often occurs in practical applications and will cause excessive system errors.

[0093] The pitch simulation standard in this embodiment is subjected to system error correction. At least two different initial positions are set, and the pitch values ​​corresponding to each simulated pitch angle at each initial position are measured; the i-th pitch value at the j-th initial position is expressed as The instrument measurement error of the i-th tooth pitch value at the j-th initial position is expressed as l represents the theoretical tooth pitch value, l = πm n .like Figure 5 As shown, a set of pitch arc length measurement results are obtained in the first initial position. (i=1,2,...8). Rotating pitch simulation standard, reference Figure 6 As shown, the position of the first tooth is changed to the second initial position to obtain the second set of pitch arc length measurement results (i=1,2,...8), and then continue to rotate and change the initial position of the first tooth until it reaches 360°, forming a closed loop. Through N azimuth changes, in this example, N=8, the corresponding error correction matrix is ​​established:

[0094]

[0095] In order to eliminate the systematic error of the instrument measurement, the correction value of each pitch value is calculated according to the error correction matrix by summing and averaging:

[0096]

[0097] In the formula, Indicates the correction value of the i-th tooth pitch value; represents the element in the i-th row and j-th column in the error correction matrix M, i∈{1,2,.....,z}, z represents the number of teeth, j∈{1,2,......,N}, N represents the total number of initial positions.

[0098] Figure 7The measurement results of the pitch simulation standard after 8 times of azimuth correction are shown. Figure 3 , Figure 7 The measurement deviation of a single tooth pitch is stable within level 0, and the cumulative deviation of the tooth pitch is 3.2μm, which is less than level 0 6.9492μm. The corrected tooth pitch value reaches level 0.

[0099] Example 2

[0100] For the simulation of the target gear sample with a larger size, the standard ball seat is arranged outside the high-precision rotating table, and the relative position between the standard ball and the high-precision rotating table is determined by the laser optical path. Figure 8 As shown, the details are as follows:

[0101] The laser interferometer 3 is arranged on the high-precision rotating table 1, the orthogonal beam splitter prism 4 is arranged in the center of the high-precision rotating table, a total reflection mirror 5 is arranged on the top of the orthogonal beam splitter prism 4, the standard ball is fixed outside the high-precision rotating table through a support seat, a magnetic positioning device is arranged in the support seat to adsorb and fix the standard ball, and a measuring mirror 6 is arranged in the area of ​​the support seat relative to the orthogonal beam splitter prism 4; the plane where the reflection surface of the measuring mirror 6 is located is the tangent plane of the standard ball;

[0102] The relative position between the standard ball and the high-precision rotating table is determined by the laser optical path: the laser beam emitted by the laser interferometer in the horizontal direction is divided into a horizontal beam and a vertical beam after reaching the orthogonal beam splitter prism; the vertical beam coincides with the central axis of the high-precision rotating table; the vertical beam reaches the total reflection mirror and is reflected back to the orthogonal beam splitter prism, and then reflected back to the laser interferometer by the orthogonal beam splitter prism; the horizontal beam reaches the measuring mirror and is reflected back to the laser interferometer;

[0103] By adjusting the position of the support seat, the distance difference between the two reflected light beams plus the radius of the standard sphere is equal to the designed distance.

[0104] When the pitch simulation standard of this embodiment is used for pitch value calibration, all steps are the same as those in Actual Example 1, except that the synchronous rotation method of the standard sphere and the high-precision rotating table is different from that in Example 1. Specifically: each time the designed pitch angle is simulated by the rotation of the high-precision rotating table, the support base is moved to a position where the center of the measuring mirror is perpendicular to the horizontal laser beam, and the distance from the support base to the orthogonal beam splitter prism is adjusted so that the distance difference between the two reflected light beams plus the radius of the standard sphere is equal to the designed distance.

[0105] Similarly, after the pitch value is calibrated, the multi-directional self-correction technology in Example 1 can be used to eliminate the system error during use.

[0106] The above technical solution is only one implementation mode of the present invention. For those skilled in the art, it is easy to make various types of improvements or modifications based on the principles disclosed in the present invention, and it is not limited to the technical solution described in the above specific embodiments of the present invention. Therefore, the above description is only preferred and does not have a restrictive meaning.

Claims

1. A design method for a pitch simulation standard, characterized in that: The following steps are involved: Obtain the parameters of the target pitch template, including pitch circle radius, pressure angle, module and number of teeth; Establish the coordinate system of the target pitch template :The center of the target pitch template is taken as the coordinate origin , along two mutually perpendicular radial directions are axis, axis; In the coordinate system of the target pitch template In the following example, it is assumed that the partial arc of a standard sphere located on the concave side of the involute of the target pitch template is used to replace the involute profile of a single tooth in the target pitch template: the intersection of the pitch circle of the target pitch template and the involute is taken as the intersection of the standard sphere in the coordinate system The tangent point of the horizontal projection circle below; According to the geometric relationship between the radius of the horizontal projection circle and the pitch circle radius of the target pitch template, the radius of the horizontal projection circle and the distance from the horizontal projection circle to the coordinate origin are calculated; The radius of the horizontal projection circle is used as the design radius of the standard sphere, and the distance from the center of the horizontal projection circle to the coordinate origin is used as the design distance from the center of the standard sphere to the central axis of the high-precision rotating table, thereby obtaining the design parameters of the pitch simulation standard; The designed pitch angle is simulated by the rotation angle of the high-precision rotary table to obtain the simulated pitch angle; the designed pitch angle , Indicates the number of teeth of the target pitch template; the pitch circle radius of the target pitch template is used as the pitch circle radius of the pitch simulation standard; the arc length corresponding to the simulated pitch angle on the pitch circle is the pitch.

2. The design method of the pitch simulation standard according to claim 1, characterized in that: The design radius of the standard sphere, that is, the radius of the horizontal projection circle, is calculated according to the following formula: ； The design distance, i.e. the distance from the center of the horizontal projection circle to the coordinate origin, is calculated according to the following formula: ； In the formula, represents the design radius of the standard sphere; Indicates the pitch circle radius of the target pitch template; Indicates the design distance from the center of the standard sphere to the central axis of the high-precision rotating table; Indicates the tooth thickness of the target pitch sample, , Represents the modulus; Indicates the pressure angle of the target pitch template.

3. A method for preparing a pitch simulation standard, characterized in that: The design parameters of the pitch simulation standard are obtained by adopting the design method of the pitch simulation standard described in any one of claims 1 or 2; a single standard ball is selected or prepared according to the design radius and the relative position of the standard ball and the high-precision rotating table is arranged according to the design distance, thereby preparing the pitch simulation standard.

4. A pitch simulation standard, characterized in that: The pitch simulation standard is prepared by the preparation method of the pitch simulation standard as claimed in claim 3.

5. The pitch simulation standard according to claim 4, characterized in that: The standard balls are arranged on the high-precision rotating table according to the designed distance.

6. The pitch simulation standard according to claim 4, characterized in that: The standard ball is arranged outside the high-precision rotating table, and the relative position between the standard ball and the high-precision rotating table is determined by the laser optical path.

7. The pitch simulation standard according to claim 6, characterized in that: The laser interferometer is arranged on a high-precision rotating table, the orthogonal beam splitter prism is arranged in the center of the high-precision rotating table, a total reflection mirror is arranged on the top of the orthogonal beam splitter prism, the standard ball is fixed outside the high-precision rotating table through a support seat, and a measuring mirror is arranged in the area of ​​the support seat opposite to the orthogonal beam splitter prism; the plane where the reflection surface of the measuring mirror is located is the tangent plane of the standard ball; The relative position between the standard ball and the high-precision rotating table is determined by the laser optical path: the laser beam emitted by the laser interferometer in the horizontal direction is divided into a horizontal beam and a vertical beam after reaching the orthogonal beam splitter prism; the vertical beam coincides with the central axis of the high-precision rotating table; the vertical beam reaches the total reflection mirror and is reflected back to the orthogonal beam splitter prism, and then reflected back to the laser interferometer by the orthogonal beam splitter prism; the horizontal beam reaches the measuring mirror and is reflected back to the laser interferometer; By adjusting the position of the support seat, the distance difference between the two reflected light beams plus the radius of the standard sphere is equal to the designed distance.

8. The pitch simulation standard according to claim 7, characterized in that: The standard ball is fixed on the support seat by a magnetic positioning device.

9. A method for calibrating a tooth pitch value, characterized in that: The pitch value of the pitch simulation standard as claimed in claim 4 is calibrated using a three-coordinate measuring machine: According to the number of teeth Determine the number of rotations of a high-precision rotary stage at the same initial position , taking the designed pitch angle as the target angle for each rotation; The standard ball at the initial position is sampled, and then the standard ball rotates synchronously with the high-precision rotating table. The standard ball is sampled every time it rotates, and the coordinates of the center of the standard ball at each position are fitted through the sampling points; The center coordinates of the pitch simulation standard are fitted through the center coordinates of the standard balls at various positions; Calculate the angles between the center coordinates of the pitch simulation standard and the lines connecting the center coordinates of the spheres at two adjacent positions as the simulated pitch angle; The arc length corresponding to each simulated pitch angle on the pitch circle is calculated to achieve the calibration of the pitch value.

10. The tooth pitch value calibration method according to claim 9, characterized in that: Error correction for the tooth pitch value: Set at least two different initial positions, and measure the pitch values ​​corresponding to each simulated pitch angle at each initial position; The first The tooth pitch value is expressed as , No. The first The instrument measurement error of the tooth pitch value is expressed as , , Indicates the theoretical tooth pitch value, , Represents the modulus, from which the error correction matrix is ​​established : Calculate the correction value of each pitch value according to the error correction matrix: In the formula, Indicates Correction value of the tooth pitch value; represents the error correction matrix Middle Line Column elements, , Indicates the number of teeth, , Indicates the total number of initial positions.

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