A gear overall error measurement device and measurement method based on double-flank meshing

Abstract

The present invention provides a double-flank meshing-based gear overall error measurement device and method. The measurement device includes a mechanical portion and an electronic control portion. The mechanical portion can achieve one linear motion and two rotational motions. The linear motion is the horizontal positional movement of the special gear, and the two rotational motions are the rotational motion of the special gear shaft system and the rotational motion of the measured gear shaft system. The special gear shaft system is the active shaft system, and the measured gear shaft system is the passive shaft system. The measurement method uses a double-flank meshing method to calculate the measured tooth profile of each tooth of the measured gear, and then calculates the tooth profile deviation, pitch deviation, and overall gear error curve of the measured gear. The instrument structure of the present invention is relatively simple and low-cost. The use of the device and method proposed by the present invention can overcome the shortcomings of traditional methods and improve the measurement efficiency of gear overall error measurement.

Description

Technical Field

[0001] The present invention relates to a gear overall error measuring device and a measuring method, belonging to the fields of gear transmission, precision testing technology and instruments, and gear detection technology. Background Art

[0002] Gears are critical components of mechanical equipment, and their quality often directly determines the equipment's operational performance, service life, safety, and reliability. Gear integral error measurement technology, pioneered by Chinese scientists in the early 1970s, has significantly advanced the technological advancement of my country's gear industry. The integral error curve obtained by a gear integral error measurement instrument vividly depicts the gear meshing transmission process, accurately revealing the changing patterns of individual gear errors and the interrelationships between them. This makes it particularly suitable for gear process error analysis and dynamic performance prediction.

[0003] Gear integral error measurement instruments offer the advantages of high measurement efficiency, rich measurement information, and a measurement process that closely resembles actual use. They are particularly suitable for precision testing and quality control of mass-produced gear products. With the trend toward 100% inspection of automotive gears, integral gear error measurement methods have enormous application value. Domestic instruments based on integral gear error measurement technology include the CZ450 (worm-type) integral gear error measuring instrument and the CZW50 (gear-type) micro-gear measuring instrument, both developed by the Chengdu Tool Research Institute. The CZ450 worm-type integral gear error measuring instrument was awarded the second prize of the National Invention Award.

[0004] Traditional gear overall error measuring instruments usually use a special measuring element "jumping worm" as the master gear (i.e. MasterGear). Based on the single-sided meshing principle, measurements are performed under the condition of an overlap coefficient of less than 1. The cross-sectional overall error curve and tangential comprehensive deviation curve of the measured gear (i.e. PartGear) can be obtained.

[0005] However, the traditional gear overall error measurement technology still has some shortcomings: (1) the left and right tooth surfaces of the gear being measured need to be measured separately, and the measurement efficiency is lower than that of double-meshing measurement; (2) the tooth-jumping worm used has a complex shape and high precision requirements, making it difficult to manufacture; (3) the installation angle of the tooth-jumping worm needs to be adjusted, and the instrument structure is relatively complex and the cost is high. Summary of the Invention

[0006] The purpose of the present invention is to propose a gear overall error measurement device and measurement method based on double-sided meshing. By adopting the double-sided meshing method, the left tooth surface and the right tooth surface of the gear being measured can be measured simultaneously, and the measurement efficiency is relatively high, which makes up for the shortcomings of traditional methods; the instrument structure is relatively simple and the cost is low. The use of the device and method proposed in the present invention can improve the measurement efficiency of the gear overall error measurement.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A double-face meshing gear overall error measurement device, comprising a mechanical part and an electronic control part;

[0009] The mechanical part can realize one linear motion and two rotational motions; the linear motion is the horizontal position movement of the MOT gear, and the two rotational motions are the rotational motion of the MOT gear shaft system and the rotational motion of the measured gear shaft system; the MOT gear shaft system is the active shaft system, and the measured gear shaft system is the passive shaft system;

[0010] The mechanical structure that enables the horizontal movement of the MOT gear includes an X-axis workbench on which the MOT gear shaft system is mounted, a precision guide rail, an X-axis displacement sensor, an X-axis clutch mechanism, an X-axis servo motor, and an X-axis linear motion mechanism. The precision guide rail constrains the movement direction of the X-axis workbench to the center distance between the gear being measured and the MOT gear, i.e., the X-axis direction, and reduces the friction force of the X-axis movement. The X-axis displacement sensor is used to obtain the center distance between the gear being measured and the MOT gear.

[0011] The X-axis clutch mechanism can be closed or opened. When the X-axis clutch mechanism is opened, the movement of the X-axis worktable is independent of the rotational movement of the X-axis linear motion mechanism and the X-axis servo motor. When the X-axis clutch mechanism is closed, the X-axis linear motion mechanism converts the rotational movement of the X-axis servo motor into linear motion, driving the movement of the X-axis worktable. There is a spring connection along the X direction between the X-axis worktable and the fixed base. When the X-axis clutch mechanism is opened, the spring force can maintain close contact between the tooth surfaces of the gear being measured and the mate tooth.

[0012] The mechanical structure that realizes the rotational motion of the Mute gear shaft system includes a driving shaft, Mute gears, bearings, and a servo motor that drives the Mute gears. An angle sensor A for obtaining the rotation angle of the Mute gears and a corresponding reading head are installed on the driving shaft. During measurement, the Mute gear shaft system drives the measured gear shaft system to rotate.

[0013] The mechanical structure that realizes the rotational motion of the gear shaft system under test includes a driven shaft, a gear under test, and a bearing. An angle sensor B for obtaining the rotation angle of the gear under test and a corresponding reading head are installed on the driven shaft.

[0014] The electronic control part includes a high-speed synchronous data acquisition system, a servo motor drive control system and a computer; the high-speed synchronous data acquisition system collects signals from various angle sensors and displacement sensors, processes them and then sends them to the computer; the computer drives and controls each servo motor through the servo motor drive control system. The computer is used to realize human-computer interaction, measurement process control, measurement data processing and storage, report printing, and network communication functions.

[0015] Furthermore, in the above-mentioned gear overall error measurement device based on double-sided meshing, when the measurement efficiency requirement is low, the X-axis clutch mechanism, X-axis servo motor and X-axis linear motion mechanism can be removed, and the position of the code gear in the horizontal direction can be adjusted manually instead.

[0016] Furthermore, in the above-mentioned gear overall error measurement device based on double-sided meshing, the spring is removed, the center distance between the code gear and the gear being measured is adjusted to a preset center distance, and the position of the code gear in the horizontal direction is locked, then the device can be used to measure the tangential comprehensive deviation of the gear being measured.

[0017] Furthermore, in the above-mentioned gear overall error measurement device based on double-sided meshing, the motor driving the matte gear does not directly drive the driving shaft, but drives the driving shaft via a gear transmission system, a belt transmission system or a friction wheel transmission system, which can also realize the measurement function.

[0018] A method for measuring overall gear error based on double-flank meshing, the method comprising the following steps:

[0019] S1: Before starting the measurement, the X-axis displacement sensor must be calibrated so that its reading can reflect the absolute value of the center distance between the Mater gear and the gear being measured;

[0020] S2: Before starting the measurement, the angle sensors A and B must be reset to zero so that their readings can reflect the absolute coordinate values ​​of the rotation angles.

[0021] S3: Before starting the measurement, install the MOT gear and align the reference tooth of the MOT gear with the axis of the gear to be measured, so that the mid-plane of the reference tooth of the MOT gear passes through the axis of the gear to be measured accurately;

[0022] S4: Before starting the measurement, the gear to be measured must be installed;

[0023] In this method, the order of the above steps S1 to S4 can be changed if feasible;

[0024] S5: Start measurement. The servo motor driving the MOT gear rotates, which in turn drives the gear being measured to rotate. During the measurement, the MOT gear and the gear being measured maintain close contact on both sides of their tooth surfaces due to the spring force.

[0025] S6: Start counting after the speed of the code gear stabilizes; while starting counting, record the current time as time t0, and record the current values ​​of the X-axis displacement sensor, angle sensor A, and angle sensor B as reference values;

[0026] S7: After counting starts, the readings of the X-axis displacement sensor, angle sensor A, and angle sensor B are obtained and recorded in real time; at time t after counting starts, the actual rotation angle of the code gear relative to the reference value recorded in S6 is recorded as The actual rotation angle of the gear under test relative to the reference value recorded in S6 is recorded as The absolute value of the center distance between the gear being tested and the gear is recorded as a c (t);

[0027] S8: After counting starts, if the left and right tooth surfaces of all the gear teeth of the gear being measured have been measured, that is, they have been meshed with the measuring tooth surface of the MT gear once, then the data collection process is determined to be completed; otherwise, the process returns to S7 and continues to collect data;

[0028] S9: Based on the tooth profile data of the gear obtained in advance and the data at each moment obtained in the above steps a c (t) data, the measured tooth profile of each gear tooth can be calculated, and then the tooth profile deviation, pitch deviation and overall gear error curve of the gear can be calculated. The steps are as follows:

[0029] 1) Obtain the parametric equations of the tooth profiles of each gear tooth, based on which the tooth profile curves of each gear tooth after the gear tooth tooth rotates at any angle relative to the initial position can be drawn;

[0030] 2) In the XOY plane, establish a coordinate system O2-X2Y2 fixed on the gear being measured, with the origin O2 selected at the rotation axis of the gear being measured;

[0031] 3) In the coordinate system O2-X2Y2, the center line O1O2 connecting the gear to be measured rotates relative to the center O2 of the gear to be measured. The center of the Mater gear changes along the center line O1O2 direction a c (t), the tooth profile of the worm gear rotates relative to the worm gear center O1 According to the law, the tooth profile curve of each tooth of the matte gear at time t in the O2-X2Y2 coordinate system is obtained;

[0032] 4) Based on the tooth profile curve of each tooth of the matt gear at time t in the O2-X2Y2 coordinate system, the maximum possible extension at the current moment in the normal direction at a point on a tooth surface of the measured gear can be obtained; by traversing the tooth profile of the matt gear at each moment in the measurement process, the maximum possible extension at each moment in the normal direction at that point on the tooth surface of the measured gear can be obtained; the minimum value of these maximum possible extensions is the measured extension in the normal direction at that point on the tooth surface of the measured gear; the measured extension in the normal direction at each point on the tooth surface is calculated to obtain the measured tooth profile of the tooth surface;

[0033] 5) After calculating the measured tooth profile of each tooth surface, the existing gear geometry and graphics knowledge can be used to calculate the tooth profile deviation, pitch deviation and overall gear error curve of the measured gear according to the gear accuracy standard.

[0034] Beneficial effects

[0035] The technical solution proposed in this invention utilizes a double-sided meshing method during measurement, allowing for simultaneous measurement of both the left and right tooth flanks of the gear being measured, resulting in relatively high measurement efficiency. A jump tooth gear, based on a cylindrical gear, is used as the code gear. The jump tooth gear's shape closely matches the gear being measured, making it relatively easy to manufacture. The axis of the jump tooth gear is typically parallel to the axis of the gear being measured, resulting in a relatively simple instrument structure and low cost. This invention, through technological innovation, addresses the shortcomings of traditional methods, promoting the widespread application of gear overall error measurement technology in the gear industry and improving the quality of mass-produced gears. It possesses significant academic and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 Schematic diagram of the gear overall error measurement device based on double-flank meshing;

[0038] Figure 2 The flowchart of the gear overall error measurement method based on double-flank meshing is shown in Figure 2.

[0039] Figure 3 The tooth surface profile of the Mater gear and the reference tooth, measuring tooth and transmission tooth;

[0040] Figure 4 is the coordinate system O2-X2Y2 (initial state) fixed on the gear being measured;

[0041] Figure 5 is the tooth profile curve of the matt gear and the gear being measured in the XOY plane at time t;

[0042] Figure 6 The tooth profile curves of the Mater gear and the gear being measured in the coordinate system O2-X2Y2 at time t;

[0043] Figure 7 Schematic diagram of the calculation process of the maximum possible extension at the midpoint A of the coordinate system O2-X2Y2 at time t;

[0044] Figure numerals: 1-angle sensor B, 2-measured gear, 3-passive shaft, 4-angle sensor B reading head, 5-code gear, 6-driving shaft, 7-angle sensor A, 8-angle sensor A reading head, 9-bearing, 10-servo motor driving the code gear, 11-X-axis displacement sensor, 12-X-axis workbench, 13-X-axis servo motor, 14-X-axis linear motion mechanism, 15-X-axis clutch mechanism, 16-spring. DETAILED DESCRIPTION

[0045] The following specific examples are provided to further clearly, completely and in detail illustrate the advantages, features and specific embodiments of the present invention in conjunction with the accompanying drawings. This embodiment is a preferred embodiment based on the technical solution of the present invention and is a non-limiting description, illustration and explanation of the present invention. However, the scope of protection of the present invention is not limited to the following examples.

[0046] This embodiment relates to a gear overall error measurement device and measurement method based on double-flank meshing.

[0047] Traditional gear overall error measurement instruments usually use a special measuring element "jumping worm" as a special gear (i.e., MasterGear). Based on the principle of single-sided meshing, the measurement is performed under the condition of overlap coefficient <1. ​​The cross-sectional overall error curve and tangential comprehensive deviation curve of the measured gear 2 (i.e., PartGear) can be obtained. However, the traditional gear overall error measurement technology still has some shortcomings: (1) The left and right tooth surfaces of the measured gear 2 need to be measured separately, and the measurement efficiency is lower than that of double-meshing measurement; (2) The skipping worm used has a complex shape and high precision requirements, which makes it difficult to manufacture; (3) The installation angle of the skipping worm needs to be adjusted, which makes the instrument structure more complex and the cost higher.

[0048] Unlike traditional methods, the technical solution in this embodiment utilizes a double-flank meshing method during measurement, allowing simultaneous measurement of both the left and right tooth flanks of the gear 2 being measured, resulting in relatively high measurement efficiency. A jump tooth gear, based on a cylindrical gear, is used as the code gear 5. The shape of this jump tooth gear, similar to that of the gear 2 being measured, makes it easier to manufacture. The axis of the jump tooth gear is typically parallel to the axis of the gear 2 being measured, resulting in a simpler instrument structure and lower cost. This technical solution, through technological innovation, addresses the shortcomings of traditional methods, promoting the widespread application of gear overall error measurement technology in the gear industry and improving the quality of mass-produced gears. It holds significant academic and practical value.

[0049] The basic working principle of the device is: the computer controls the rotational movement of the matt gear 5 and the gear to be measured 2 through a servo motor. Under the action of the spring force, the matt gear 5 and the gear to be measured 2 realize double-sided meshing rolling measurement, during which the center distance of the two gears can change; the computer collects the signals of each angle sensor and displacement sensor through a high-speed synchronous data acquisition system, and after analysis and data processing, the actual tooth profile of the gear to be measured 2 can be calculated, and the overall error, each individual error and comprehensive error of the gear to be measured 2 can be obtained according to the international and national standards for gear accuracy.

[0050] The Mastergear 5 (i.e., previously translated as "standard gear" or "measurement gear" in literature, which is easy to confuse the meaning; the new national standard recommends translating it as "Mastergear") should use a "jump tooth gear" when high measurement accuracy is required, and ordinary gears with higher manufacturing accuracy can also be used when low measurement accuracy is required. The "jump tooth gear" is made based on ordinary gears with higher precision. The jump tooth gear selects a number of "measurement teeth" at a certain number of intervals in the circumferential direction (usually 1 tooth or 2 teeth, or more teeth can be spaced). The teeth other than the measurement teeth are called "transmission teeth". The tooth surfaces on both sides of the transmission teeth must be thinned to ensure that the overlap coefficient in the measurement is less than 1, that is, the number of tooth pairs of the driving gear and the driven gear that are simultaneously engaged in tooth surface meshing does not exceed 1.

[0051] like Figure 1 As shown, in order to solve the problems existing in the prior art, a gear overall error measurement device based on double-sided meshing is proposed, which includes a mechanical part and an electronic control part.

[0052] The mechanical part can achieve one linear motion and two rotational motions. The linear motion is the horizontal positional movement of the Mater gear 5, and the two rotational motions are the rotational motion of the Mater gear shaft system and the rotational motion of the shaft system of the gear under test 2. The Mater gear shaft system is the active shaft system 6, and the shaft system of the gear under test 2 is the passive shaft system 3.

[0053] The mechanical structure that enables the horizontal movement of the matt gear 5 includes an X-axis worktable 12 on which the matt gear shaft system is mounted, a precision guide rail, an X-axis displacement sensor 11, an X-axis clutch mechanism 15, an X-axis servo motor 13, and an X-axis linear motion mechanism 14. The precision guide rail constrains the movement direction of the X-axis worktable 12 to the center distance between the measured gear 2 and the matt gear 5 (i.e., the X-axis direction) and reduces the friction force of movement in the X-axis direction. The X-axis displacement sensor 11 is used to obtain the center distance between the measured gear 2 and the matt gear 5. The X-axis clutch mechanism 15 can be closed or opened. When the X-axis clutch mechanism 15 is opened, the movement of the X-axis worktable 12 is independent of the rotational movement of the X-axis linear motion mechanism 14 and the X-axis servo motor 13. When the X-axis clutch mechanism 15 is closed, the X-axis linear motion mechanism 14 converts the rotational movement of the X-axis servo motor 13 into linear motion, driving the movement of the X-axis worktable 12.

[0054] A spring 16 is connected between the X-axis workbench 12 and the fixed base along the X direction. When the X-axis clutch mechanism 15 is disconnected, the spring force can keep the measured gear 2 in close contact with the double-sided tooth surfaces of the code tooth.

[0055] The mechanical structure that realizes the rotational motion of the sprocket gear shaft system includes a drive shaft 6, a sprocket gear 5, bearings 9, and a servo motor 10 that drives the sprocket gear. Mounted on the drive shaft 6 is an angle sensor A7 for detecting the rotation angle of the sprocket gear 5, along with a corresponding angle sensor A reading head 8. During measurement, the sprocket gear shaft system rotates the shaft system of the gear 2 being measured.

[0056] The mechanical structure that realizes the rotational motion of the gear 2 includes a driven shaft 3, the gear 2, and a bearing 9. An angle sensor B1 for obtaining the rotation angle of the gear 2 and a corresponding angle sensor B reading head 4 are installed on the driven shaft 3.

[0057] The electronic control system includes a high-speed synchronous data acquisition system, a servo motor drive control system, and a computer. The high-speed synchronous data acquisition system collects signals from the angle sensors and displacement sensors, processes them, and then transmits them to the computer. The computer drives and controls the servo motors through the servo motor drive control system. The computer is used for human-computer interaction, measurement process control, measurement data processing and storage, report printing, and network communication.

[0058] Furthermore, in the above-mentioned gear overall error measurement device based on double-sided meshing, when the measurement efficiency requirement is low, the X-axis clutch mechanism 15, the X-axis servo motor 13 and the X-axis linear motion mechanism 14 can be removed, and the position of the code gear 5 in the horizontal direction can be adjusted manually instead.

[0059] Furthermore, in the above-mentioned gear overall error measurement device based on double-sided meshing, the spring 16 is removed and the position of the code gear 5 in the horizontal direction is locked, and after the center distance between the code gear 5 and the gear to be measured 2 is adjusted appropriately, it can be used to measure the tangential comprehensive deviation of the gear to be measured 2.

[0060] Furthermore, in the above-mentioned gear overall error measurement device based on double-sided meshing, the motor driving the matte gear may not directly drive the active shaft 6, but may drive the active shaft 6 via a gear transmission system, a belt transmission system or a friction wheel transmission system, and the measurement function can also be achieved.

[0061] Figure 1 In the figure, angle sensor A7 and angle sensor B1 usually adopt circular gratings; in order to improve the measurement accuracy, a circular grating equipped with multiple reading heads can be used, or a solution in which two circular gratings are arranged on one axis can be used (refer to the public patent with application number 201710464459.0 and patent name "Axis system five- and six-degree-of-freedom error measurement method and measurement system based on circular grating").

[0062] Figure 1 In the embodiment, the X-axis displacement sensor 11 typically employs a grating ruler. To improve measurement accuracy, a grating ruler with multiple readout heads can be used, or two grating rulers can be arranged on one axis. Alternatively, the X-axis displacement sensor 11 can employ a laser interferometer, a laser triangulation displacement sensor, an inductive, capacitive, or other type of displacement sensor. A variety of sensors can be used as long as they meet the required accuracy and cost constraints.

[0063] Further, Figure 1 In the design of the bearings 9 on the active shaft 6 and the passive shaft 3, a single bearing solution, a two-bearing solution, or a plurality of bearing solutions can be used; the types of bearings that can be used include sliding bearings, rolling bearings, air bearings, liquid static bearings, liquid dynamic bearings, magnetic bearings, etc.; various bearing types can be selected as long as they can meet the accuracy requirements and cost constraints.

[0064] Further, Figure 1In the embodiment, the servo motor 10 driving the code gear can be selected from types such as a DC brushed motor, a DC brushless motor, a DC synchronous motor, an AC servo motor, an AC motor, and a direct drive motor. The selected servo motor should have a uniform speed and small torque fluctuation (the current stepper motor generally has a large torque fluctuation and is not suitable for selection), and has a speed regulation function; the servo motor 10 driving the code gear can be directly connected to the active shaft 6 with a coupling, or it can be connected through a reducer. The servo motor can also be designed on the side of the active shaft 6, and the code gear 5 (active shaft 6) can be driven by a gear transmission or a friction wheel transmission. In principle, it is feasible to let the servo motor not drive the code gear 5 (active shaft 6), but drive the measured gear 2 (passive shaft 3), and the measured gear 2 (passive shaft 3) drives the code gear 5 (active shaft 6) for measurement, and the measurement can also be achieved. If the measurement efficiency and measurement accuracy requirements are not high, removing the servo motor and using hand-cranking or manual methods for measurement is also a feasible implementation method.

[0065] Further, Figure 1 In the example, the X-axis worktable 12 is mounted on a precision guide rail. Common precision guide rails include sliding guides, rolling guides, and air bearing guides. Precision guide rails should have high guiding accuracy and low friction to improve measurement accuracy. Common guide rail brands include Hiwin and THK.

[0066] Further, Figure 1 The X-axis servo motor 13 can be a brushed DC motor, a brushless DC motor, a synchronous DC motor, an AC servo motor, or a direct-drive motor. The servo motor can be directly connected to the X-axis linear motion mechanism 14 (e.g., a screw-nut pair) using a coupling or a speed reducer. If measurement efficiency is not critical, removing the servo motor and manually adjusting the position of the X-axis worktable 12 can also be a viable option.

[0067] Further, Figure 1 In the embodiment, the X-axis linear motion mechanism 14 is usually implemented by a screw-nut pair. The X-axis linear motion mechanism 14 can also be implemented by a steel belt drive, a synchronous toothed belt drive, a friction drive, etc., as long as the accuracy and cost requirements are met.

[0068] Further, Figure 1 In the embodiment, the X-axis clutch mechanism 15 can be implemented using electromagnetic brakes, cylinder locking, or other methods, and needs to have two operating states: closed and open. When the clutch mechanism is closed, the movement of the X-axis linear motion mechanism 14 and the X-axis worktable 12 are interdependent; when the clutch mechanism is open, the movement of the X-axis linear motion mechanism 14 and the X-axis worktable 12 are independent.

[0069] Further, Figure 1In the figure, the role of spring 16 is to provide a driving force. When the X-axis clutch mechanism 15 is disconnected, the driving force keeps the gear 2 under test in close contact with the tooth surfaces on both sides of the code tooth, thereby realizing a double-sided meshing measurement method. The spring 16 can be made of metal or rubber; the spring 16 can be in the form of providing tension or thrust; the spring 16 can be a cylindrical wound spring, or in the form of a spring plate or spring wire. The loading method of this driving force can also be changed to gravity loading, magnetic loading, electromagnetic loading, etc. As long as a suitable driving force can be provided, the gear 2 under test can be kept in close contact with the tooth surfaces on both sides of the code tooth during the measurement process without causing excessive deformation, various loading methods can be used.

[0070] Further, Figure 1 In the servo motor drive control system, motion control cards, motion controllers, single-chip microcomputer application systems, DSP / FPGA circuit boards and other implementation methods can be used; high-speed synchronous data acquisition systems can be implemented by motion control cards, counter cards, motion controllers, single-chip microcomputer application systems, DSP / FPGA circuit boards and other implementation methods; computers can be implemented by home PCs, commercial PCs, industrial PCs, PLC controllers, single-chip microcomputer application systems, DSP / FPGA circuit boards, cloud computing platforms and other implementation methods.

[0071] like Figure 2 As shown, a method for measuring overall gear error based on double-sided meshing includes the following steps:

[0072] S1: Before the measurement begins, the X-axis displacement sensor 11 must be calibrated so that its reading can reflect the absolute value of the center distance between the matt gear 5 and the gear being measured 2;

[0073] S2: Before starting the measurement, the angle sensor A7 and the angle sensor B1 must be reset to zero so that their readings can reflect the absolute coordinate value of the rotation angle;

[0074] S3: Before starting the measurement, install the matt gear 5 and align the reference tooth of the matt gear 5 with the axis of the gear 2 to be measured, so that the bisecting plane of the reference tooth of the matt gear 5 passes through the axis of the gear 2 to be measured as accurately as possible;

[0075] S4: Before the measurement begins, the gear 2 to be measured must be installed;

[0076] The order of the above four steps can be changed if feasible;

[0077] S5: Start measurement, drive the servo motor 10 of the special gear to rotate, drive the special gear 5 to rotate, and the special gear 5 drives the measured gear 2 to rotate; during the measurement process, under the action of the spring force, the special gear 5 and the measured gear 2 maintain close contact on both sides of the tooth surface;

[0078] S6: Start counting after the speed of the code gear 5 stabilizes; while starting counting, record the current time as time t0, and record the current values ​​of the X-axis displacement sensor 11, angle sensor A7, and angle sensor B1 as reference values;

[0079] S7: After counting starts, the readings of the X-axis displacement sensor 11, the angle sensor A7, and the angle sensor B1 are obtained and recorded in real time; at time t after counting starts, the actual rotation angle of the code gear 5 (relative to the reference value recorded in S6) is recorded as The actual rotation angle of the gear 2 under test (relative to the reference value recorded in S6) is recorded as The absolute value of the center distance between the tested gear 2 and the matt gear 5 is recorded as a c (t);

[0080] S8: After counting starts, if the left and right tooth surfaces of all the teeth of the gear 2 to be measured have been measured (i.e., they have been meshed with the measuring tooth surface of the matte gear 5 once), the data collection process is determined to be completed; otherwise, the process returns to S7 and continues to collect data;

[0081] S9: Based on the tooth profile data of the 5th gear obtained in advance and the data at each moment obtained in the above steps a c (t) data, the measured tooth profile of each tooth of the measured gear 2 can be calculated, and then the tooth profile deviation, pitch deviation and overall gear error curve of the measured gear 2 can be calculated. The steps are as follows:

[0082] (1) Obtain the parametric equations of the tooth profiles of each tooth of the matt gear 5, based on which the tooth profile curves of each tooth of the matt gear 5 after rotating at any angle relative to the initial position can be drawn;

[0083] (2) In the XOY plane, a coordinate system O2-X2Y2 fixed on the gear 2 to be measured is established, and the origin O2 is selected at the rotation axis of the gear 2 to be measured;

[0084] (3) In the coordinate system O2-X2Y2, the center line O1O2 connecting the gear 5 and the gear 2 to be measured rotates relative to the center O2 of the gear 2 to be measured. The center of the gear 5 changes along the center line O1O2 direction a c (t), the tooth profile of the code gear 5 rotates relative to the center O1 of the code gear 5 The tooth profile curve of each tooth of the mate gear 5 at time t in the O2-X2Y2 coordinate system is obtained according to the law;

[0085] (4) According to the tooth profile curve of each tooth of the code gear 5 at time t in the O2-X2Y2 coordinate system, the maximum possible extension at the current moment in the normal direction at a point on a tooth surface of the measured gear 2 can be obtained; by traversing the tooth profile of the code gear 5 at each moment in the measurement process, the maximum possible extension at each moment in the normal direction at that point on the tooth surface of the measured gear 2 can be obtained; the minimum value of these maximum possible extensions is obtained, which is the measured extension in the normal direction at that point on the tooth surface of the measured gear 2; the measured extension in the normal direction at each point on the tooth surface is calculated, and the measured tooth profile of the tooth surface is obtained;

[0086] (5) After calculating the measured tooth profile of each tooth surface, the existing gear geometry and graphics knowledge can be used to calculate the tooth profile deviation, pitch deviation and overall gear error curve of the measured gear 2 according to the gear accuracy standard.

[0087] In specific implementation, in step S1 above, when calibrating the X-axis displacement sensor 11, a calibration mandrel can be installed on each of the active shaft 6 and the passive shaft 3. The diameters of both mandrels are known. The X-axis worktable 12 is adjusted so that the outer diameters of the two mandrels just touch each other. At this point, the center distance between the active shaft 6 and the passive shaft 3 is known (equal to the average diameter of the two mandrels). This known center distance data is used to correct the indication of the X-axis displacement sensor 11, thereby achieving calibration of the X-axis displacement sensor 11.

[0088] In practice, in step S2 above, when performing the zero return operation on angle sensors A7 and B1, the usual approach is to capture the zero pulse of the circular grating and reset the circular grating's reading at the zero pulse to complete the zero return operation. Thereafter, the circular grating's reading is no longer reset to zero, and its reading reflects the absolute value of the rotation angle.

[0089] In specific implementation, in the above S3, when aligning the reference teeth of the code gear 5 with the axis of the gear 2 to be measured, even if the mid-plane of the reference teeth of the code gear 5 passes through the axis of the gear 2 to be measured as accurately as possible, a spherical pitch gauge can be used to adjust the center of the spherical pitch gauge to the plane formed by the axes of the code gear 5 and the gear 2 to be measured, so that the tooth surfaces on both sides of the left (or right) tooth groove of the code gear 5 are in contact with the spherical pitch gauge at the same time, thereby achieving the alignment of the adjacent tooth grooves of the code gear 5 reference teeth with the axis of the gear 2 to be measured; at this time, the code gear 5 is rotated by half the pitch angle (the precise actual rotation angle can be obtained by the angle sensor A7), thereby achieving the alignment of the reference teeth of the code gear 5 with the axis of the gear 2 to be measured. In actual implementation, an industrial camera (or machine vision system) with measurement function is installed above the code gear 5 to also achieve the position alignment of the reference teeth of the code gear 5.

[0090] In specific implementation, in the above S4, the gear 2 to be measured can be fixed by an expandable shaft during installation, or it can be fixed by threaded compression, magnetic attraction, bonding, etc., so that the gear 2 to be measured is firmly installed on the passive shaft 3, and no or only very small relative rotation occurs during the measurement process.

[0091] In practice, if feasible (i.e., guaranteed to be feasible), the order of steps S1-S4 is not strictly defined and can be selected at will. However, in practice, for a specific mechanical design, it may be impossible to install the calibration mandrel after the gear 2 under test has been installed. In this case, it is important to select a reasonable order. This order is within the skill of an engineer of ordinary skill in the art.

[0092] In practice, in step S5 above, the speed of the servo motor driving the matte gear 5 must be appropriately set. If the speed is too low, the measurement efficiency will be too low; if the speed is too high, disengagement may occur, and the bilateral tooth surface engagement measurement state cannot be maintained. The spring force must also be appropriately selected. Excessive spring force can cause significant deformation of the instrument's mechanical structure, affecting measurement accuracy; too little spring force can easily lead to disengagement due to inertia.

[0093] During specific implementation, in the above S6, the speed of the code gear 5 will undergo a speed-up process when the motor starts. It is necessary to reasonably select the time to start counting, that is, to start counting after the speed is basically stable. If it is convenient to process data, you can choose to start counting when the reference tooth of the code gear 5 rotates to face the axis of the gear 2 being measured (that is, the position in S3), but doing so will cause the total measurement time to be longer and the efficiency to be lowered. Another more reasonable processing method is to adjust the position of the code gear 5 in S3, record the absolute coordinate value of the angle sensor A7 after the return to zero operation in S2, consider the initial position of the reference tooth of the code gear 5 when processing the data, and translate the measurement results of each sensor along the time axis. Regardless of which of the above two processing methods is used, when calculating the gear error after the measurement data is collected, it can be considered that counting starts when the reference tooth of the code gear 5 rotates to face the axis of the gear 2 being measured (that is, the position in S3), so that the calculation process is relatively simple.

[0094] When counting starts, the current time is recorded as time t0, and the current values ​​of the X-axis displacement sensor 11, angle sensor A7, and angle sensor B1 are recorded as reference values, which are a c (t0), and

[0095] In the specific implementation, in the above S7, the work of obtaining and recording the readings of the X-axis displacement sensor 11, the angle sensor A7 and the angle sensor B1 in real time is completed by a computer-controlled high-speed synchronous data acquisition system. a c In addition to (t), the theoretical speed of the code gear 5 can also be recorded as ω 10 , the actual speed of the gear 5 is recorded as ω1(t); the theoretical speed of the gear 2 is recorded as ω 20 , the actual speed of the measured gear 2 is recorded as ω2(t); the theoretical rotation angle of the gear 5 is recorded as The rotation angle error of the gear 5 is recorded as The theoretical rotation angle of the gear 2 under test is recorded as The rotation angle error of the measured gear 2 is recorded as The center distance variation between the tested gear 2 and the matte gear 5 is recorded as Δa c (t); then the relevant parameters can be calculated by the following calculation formula:

[0096] Where Z1 is the number of teeth of the 5-tooth gear of the Mater gear, and Z2 is the number of teeth of the 2-tooth gear of the tested gear;

[0097]

[0098]

[0099]

[0100]

[0101] Δa c (t) = a c (t)-a c (t0);

[0102] Among them, the center distance variation of the measured gear 2 and the matte gear 5 is Δa c (t) is the traditional gear radial comprehensive deviation curve; and Δa c (t) curves can be drawn on the measurement report as a reference for judging whether the measurement process is normal, judging the gear processing quality and predicting the gear performance.

[0103] In the specific implementation, in the above S8, since the jump tooth gear is used as the code gear 5, the measurement order of each gear tooth of the measured gear 2 is not carried out in the order of natural numbers. For example, if the number of transmission teeth between the two measuring teeth of the jump tooth gear is 2, as shown in FIG. Figure 3As shown, the measured gear 2 has 10 teeth, with tooth 1 measured first. Therefore, the order of the measured tooth grooves on the measured gear 2 is 1#, 4#, 7#, 10#, 3#, 6#, 9#, 2#, 5#, and 8#. This order is based on the same principle as traditional gear overall error measurement. It should be noted that the tooth and tooth groove numbers of the measured gear 2 are not necessarily arranged in clockwise or counterclockwise order. If the numbering order or the rotation direction of the metric gear 5 changes, the measured tooth groove order may also change. If the numbering sequence between the two measured teeth of the jump gear is 2 (or 3), and the number of teeth on the measured gear 2 is an integer multiple of 2 (or 3), then in order to complete the measurement, the metric gear 5 and the measured gear 2 must be disengaged at an appropriate time during the measurement process. The metric gear 5 must rotate a certain pitch angle before reengaging to complete the measurement of all tooth surfaces. This principle is also the same as traditional gear overall error measurement. When it is determined that the left and right tooth surfaces of all the teeth of the gear 2 to be measured have been measured, it can be determined that the data collection process has been completed.

[0104] In specific implementation, in step (1) of S9 above, the parameter equations of the tooth profiles of the matte gear 5 are obtained based on the input parameters of the matte gear 5 or the measurement results of the actual matte gear 5. Figure 3 The tooth profile curve of the MT gear 5 is drawn according to the input parameters. The tooth profile curve can be expressed by the parametric equation r = r (θ), where the length r is the polar diameter from the origin O2 to any point on the profile, and the polar angle θ is the angle between the positive direction of the X axis and the vector The angle between them. Figure 3 The radius between the tooth profiles near the tooth root is the base circle radius r b The tooth profiles near the tooth top are connected by an arc with a radius of the tooth top circle r. a Arc connection. Figure 3 The teeth marked ① on the middle jump tooth gear are the reference teeth, the teeth marked ① and ④ are the measuring teeth, and the teeth marked ② and ③ are the transmission teeth (the tooth surfaces on both sides are thinned, and the thinning amount is generally 30 to 50 microns). The other teeth are defined as measuring teeth and transmission teeth according to the rule that two transmission teeth are spaced between two measuring teeth. The specific formula of the parametric equation r=r(θ) of the tooth surface profile curve of the Code Gear 5 can be obtained by referring to the gear manual or the applicant's published papers (such as "Basic Theory and Application Research of Gear Overall Error Measurement"). If the Code Gear 5 used has actual tooth profile data obtained through precise measurement, the tooth profile data obtained by actual measurement is preferred, which can improve the measurement accuracy.

[0105] In specific implementation, in step (2) of S9 above, if Figure 4As shown, in the XOY plane, a coordinate system O2-X2Y2 is established and fixed on the gear 2 being measured, and the origin O2 is selected at the rotation axis of the gear 2 being measured. The coordinate system O2-X2Y2 will rotate with the gear 2 being measured.

[0106] In specific implementation, in step (3) of S9 above, Figure 5 The figure shows that in the XOY plane, at time t, the measured gear 2 rotates relative to the center O2 of the measured gear 2 - The center of the gear 5 changes along the center line O1O2 direction a c (t), the code gear 5 rotates relative to the code gear 5 center O1 Figure 6 The figure shows that in the coordinate system O2-X2Y2, the center line O1O2 connecting the gear 5 and the gear 2 to be measured rotates relative to the center O2 of the gear 2 to be measured. The center of the gear 5 changes along the center line O1O2 direction a c (t), the tooth profile of the code gear 5 rotates relative to the center O1 of the code gear 5 The tooth profile curves of each tooth of the Mater gear 5 at time t in the O2-X2Y2 coordinate system can be obtained by comparing Figure 3 、 Figure 5 、 Figure 6 It can be seen that when the a c When the (t) data is known, the tooth profile curve of the matte gear 5 in the O2-X2Y2 coordinate system at each moment can be calculated.

[0107] In specific implementation, in step (4) of the above S9, the process of obtaining the maximum possible extension of a point on the tooth surface of the measured gear 2 in the normal direction at the current moment according to the tooth profile curve of each tooth of the code gear 5 at time t in the O2-X2Y2 coordinate system is as follows: Figure 7 As mentioned above, when calculating the gear error after the measurement data is collected, it can be considered that the counting starts when the reference tooth of the code gear 5 rotates to face the axis of the measured gear 2 (i.e., the position in S3). Figure 7 In the O2-X2Y2 coordinate system, the gear 2 to be measured is fixed on the gear 2 and does not rotate. In the O2-X2Y2 coordinate system, the gear 2 to be measured always maintains Figure 4 Taking the calculation of the maximum possible extension of point A on the right tooth surface corresponding to tooth groove ① as an example, according to the drawing parameters of the gear 2 to be measured, including the number of teeth, module, pressure angle, helix angle, modification coefficient, normal length, etc., the following can be established: Figure 7The theoretical contour line of the gear 2 under test is shown in , and the tooth surface normal AC at any point A on the theoretical contour line is calculated, where C is the tangent point of the normal line at point A and the base circle, and the length of the line segment CA is the theoretical extension of point A. The coordinates of point C and point A can be calculated, and the coordinates of point C and point A are fixed in O2-X2Y2 during the measurement process. The tooth profile curve of the mate gear 5 at time t has been calculated in step (3) of S9. Based on the knowledge of analytical geometry, the intersection point A' of the straight line CA and the right tooth surface of the mate gear No. 1 can be calculated, and the length of the line segment A'C can be calculated. This length is the maximum possible extension at point A of the gear 2 under test at time t. According to this method, the tooth profile of the mate gear 5 at each moment in the measurement process is traversed and calculated once, and the maximum possible extension at each moment in the normal direction of point A on the tooth surface of the gear 2 under test can be obtained; the minimum value of these maximum possible extensions is the measured extension in the normal direction of that point on the tooth surface of the gear 2 under test. By calculating the measured extension in the normal direction at each point on the tooth surface, the measured tooth profile of the tooth surface is obtained.

[0108] In specific implementation, in step (5) of S9, after calculating the measured tooth profile of each tooth surface using the method in step (4) of S9, the tooth profile deviation, pitch deviation, and overall gear error curve of the gear 2 under test can be calculated using existing knowledge of gear geometry and graphics, in accordance with gear accuracy standards. The gear accuracy standards used herein include GB / T10095.1-2022, GB / T10095.2-2008, GB / Z18620.1-2008, etc. Calculating various gear errors based on the measured tooth profile of the gear 2 under test is a common technique that is widely used in various gear measuring equipment and can be implemented by engineers and technicians in this field.

[0109] The gear overall error measurement device proposed in this invention is a multifunctional measuring device that can perform both double-meshing and single-meshing measurements (when spring 16 is removed and the X-axis worktable 12 is locked). Measurable items include radial composite deviation curves, tangential composite deviation curves, and overall error curves, as well as tooth profile deviation, pitch deviation, tooth thickness, and ring gear runout, which can be calculated from the overall error curves. These are simple inferences about the method and device of this invention, and others should not apply for additional patents based on the content provided in the description of the embodiments.

[0110] Those skilled in the art should understand that the above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. The present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes or modifications based on actual circumstances. These equivalent changes and modifications also fall within the scope defined by the claims of the present invention.

Claims

1. An error measurement method based on a double-sided meshing gear overall error measurement device, characterized in that: The error measurement device includes a mechanical part and an electronic control part; the mechanical part realizes one linear motion and two rotational motions; the linear motion is the horizontal position movement of the mate gear, and the two rotational motions are the rotational motion of the mate gear shaft system and the rotational motion of the measured gear shaft system; The components of the mechanical structure for realizing the horizontal position movement of the MOT gear include an X-axis workbench for installing the MOT gear shaft system, a precision guide rail, an X-axis displacement sensor, an X-axis clutch mechanism, an X-axis servo motor and an X-axis linear motion mechanism; The mechanical structure that realizes the rotational motion of the MOT gear shaft system includes a driving shaft, MOT gears, bearings, and a servo motor that drives the MOT gears. An angle sensor A for obtaining the rotation angle of the MOT gears and a corresponding reading head are installed on the driving shaft. The mechanical structure for achieving the rotational motion of the gear shaft under test comprises a driven shaft, a gear under test, and a bearing; an angle sensor B for obtaining the rotation angle of the gear under test and a corresponding reading head are mounted on the driven shaft; The error measurement method includes the following steps: S1: Before starting the measurement, the X-axis displacement sensor must be calibrated so that its reading can reflect the absolute value of the center distance between the Mater gear and the gear being measured; S2: Before starting the measurement, the angle sensors A and B must be reset to zero so that their readings can reflect the absolute coordinate values ​​of the rotation angles. S3: Before starting the measurement, install the MOT gear and align the reference tooth of the MOT gear with the axis of the gear to be measured, so that the mid-plane of the reference tooth of the MOT gear passes through the axis of the gear to be measured accurately; S4: Before the measurement begins, the gear to be measured must be installed. S5: The measurement begins, and the servo motor driving the Mater gear rotates, which in turn drives the Mater gear to rotate, and the Mater gear drives the gear to be measured to rotate. During the measurement, under the action of the spring force, the Mater gear and the gear to be measured maintain close contact on both sides of the tooth surface. S6: Start counting after the speed of the code gear stabilizes; while starting counting, record the current time as time t0, and record the current values ​​of the X-axis displacement sensor, angle sensor A, and angle sensor B as reference values; S7: After counting starts, the readings of the X-axis displacement sensor, angle sensor A, and angle sensor B are obtained and recorded in real time; at time t after counting starts, the actual rotation angle of the code gear relative to the reference value recorded in S6 is recorded as The actual rotation angle of the gear under test relative to the reference value recorded in S6 is recorded as The absolute value of the center distance between the gear being tested and the gear is recorded as a c (t); S8: After counting starts, if the left and right tooth surfaces of all the gear teeth of the gear being measured have been measured, that is, they have been meshed with the measuring tooth surface of the MT gear once, then the data collection process is determined to be completed; otherwise, the process returns to S7 and continues to collect data; S9: Based on the tooth profile data of the gear obtained in advance and the data at each moment obtained in the above steps a c (t) data, the measured tooth profile of each gear tooth can be calculated, and then the tooth profile deviation, pitch deviation and overall gear error curve of the gear can be calculated. The steps are as follows: 1) Obtain the parametric equations of the tooth profiles of each gear tooth, based on which the tooth profile curves of each gear tooth after the gear tooth tooth rotates at any angle relative to the initial position can be drawn; 2) In the XOY plane, establish a coordinate system O2-X2Y2 fixed on the gear being measured, with the origin O2 selected at the rotation axis of the gear being measured; 3) In the coordinate system O2-X2Y2, the center line O1O2 connecting the gear and the gear being measured rotates relative to the center O2 of the gear being measured. The center of the Mater gear changes along the center line O1O2 direction a c (t), the tooth profile of the worm gear rotates relative to the worm gear center O1 "The tooth profile curve of each tooth of the Mater gear at time t in the O2-X2Y2 coordinate system is obtained according to the law; 4) Based on the tooth profile curve of each tooth of the matt gear at time t in the O2-X2Y2 coordinate system, the maximum possible extension at the current moment in the normal direction at a point on a tooth surface of the measured gear can be obtained; by traversing the tooth profile of the matt gear at each moment in the measurement process, the maximum possible extension at each moment in the normal direction at that point on the tooth surface of the measured gear can be obtained; the minimum value of these maximum possible extensions is the measured extension in the normal direction at that point on the tooth surface of the measured gear; the measured extension in the normal direction at each point on the tooth surface is calculated to obtain the measured tooth profile of the tooth surface; 5) After calculating the measured tooth profile of each tooth surface, the existing gear geometry and graphics knowledge can be used to calculate the tooth profile deviation, pitch deviation and overall gear error curve of the measured gear according to the gear accuracy standard.

2. The error measurement method according to claim 1, wherein: The precision guide rail constrains the movement direction of the X-axis worktable to the center distance direction of the measured gear and the MOT gear, that is, the X-axis direction, and reduces the friction force of the X-axis movement; the X-axis displacement sensor is used to obtain the center distance between the measured gear and the MOT gear.

3. The error measurement method according to claim 2, wherein: The X-axis clutch mechanism can be closed or opened. When the X-axis clutch mechanism is opened, the movement of the X-axis worktable is independent of the rotational movement of the X-axis linear motion mechanism and the X-axis servo motor. When the X-axis clutch mechanism is closed, the X-axis linear motion mechanism converts the rotational movement of the X-axis servo motor into linear motion, driving the X-axis worktable to move. There is a spring connection along the X direction between the X-axis worktable and the fixed base. When the X-axis clutch mechanism is opened, the spring force can keep the measured gear in close contact with the double-sided tooth surface of the code tooth.

4. The error measurement method according to claim 3, wherein: The electronic control part includes a high-speed synchronous data acquisition system, a servo motor drive control system and a computer; The high-speed synchronous data acquisition system collects signals from various angle sensors and displacement sensors, processes them and then sends them to the computer; the computer drives and controls each servo motor through the servo motor drive control system. The computer is used to realize human-computer interaction, measurement process control, measurement data processing and storage, report printing and network communication functions.

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