1. A method for optimizing the tooth profile of a rigid wheel of a harmonic reducer is characterized by comprising the following steps: the method specifically comprises the following steps:

s1, forming an observation gap on the harmonic reducer rigid wheel through secondary cutting processing;

s2, mounting the cut harmonic reducer in a harmonic reducer flexible gear tooth radial deformation measuring device, and measuring by the harmonic reducer flexible gear tooth radial deformation measuring device to obtain flexible gear parameters of the harmonic reducer in a meshing motion state;

s3, processing the obtained flexbile gear parameters through MATLAB, substituting the processed flexbile gear parameters into a flexbile gear motion trail equation, and obtaining a motion trail highly fitting the real flexbile gear motion through MATLAB simulation;

and S4, taking a flexible gear motion track envelope curve obtained based on the simulation of the radial deformation of the real flexible gear, and fitting the envelope curve by adopting a plurality of sections of circular arcs based on the envelope curve to obtain the optimized rigid gear tooth shape.

2. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 1, wherein the method comprises the following steps: the observation notch in the step S1 is in the shape of a sector, the centers of two arcs of the sector are both located on the central axis of the rigid wheel, the radii of the two arcs are respectively equal to the radius of the addendum circle of the rigid wheel and the radius of the outer contour of the rigid wheel, and the height of the sector is equal to the length of the gear of the rigid wheel.

3. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 2, wherein the method comprises the following steps: the degree of the central angle corresponding to the fan-shaped body is 27.5 degrees.

4. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 2, wherein the method comprises the following steps: the device for measuring the radial deformation of the flexible gear teeth of the harmonic reducer comprises a moving device body part and a parameter measuring part, wherein the moving device body part and the parameter measuring part are fixedly installed on a fixed base.

5. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 4, wherein the method comprises the following steps: the moving device body part comprises an alternating current servo motor, an Oldham coupling I, a torque and rotating speed sensor I, an Oldham coupling II, a harmonic reducer after cutting processing, a flange coupling, a torque and rotating speed sensor II, an Oldham coupling III and a magnetic powder brake; the alternating current servo motor drives the first torque and speed sensor to rotate through the first crosshead shoe coupler, the first torque and speed sensor drives the harmonic reducer after cutting through the second crosshead shoe coupler to rotate, the harmonic reducer after cutting drives the second torque and speed sensor to rotate through the flange coupler, and the second torque and speed sensor drives the magnetic powder brake to rotate through the third crosshead shoe coupler.

6. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 5, wherein the method comprises the following steps: alternating current servo motor fixed mounting on motor unable adjustment base, torque speed sensor one and torque speed sensor two are fixed respectively on sensor fixing base one and sensor fixing base two, harmonic speed reducer ware fixed mounting after the cutting process is on speed reducer ware unable adjustment base, motor unable adjustment base, sensor fixing base one, sensor fixing base two, speed reducer ware unable adjustment base and magnetic powder brake respectively fixed mounting be in unable adjustment base is last.

7. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 5, wherein the method comprises the following steps: the parameter measuring part comprises a first fixed support plate, a second fixed support plate, a three-degree-of-freedom displacement table, a displacement table fixing plate and a sensor fixing plate, the first fixed support plate and the second fixed support plate are symmetrically arranged in the middle of the fixed base in the width direction in parallel, a third fixed support plate is connected between the first fixed support plate and the second fixed support plate, the three-degree-of-freedom displacement table is formed by connecting three displacement tables in different displacement directions, the bottom of the three-degree-of-freedom displacement table is fixed at the central position of the displacement table fixing plate, and the displacement table fixing plate is fixed on the first fixed support plate and the second fixed support plate; the point laser displacement sensor is fixed at one end of the sensor fixing plate, and the sensor fixing plate is fixed on one of the three-degree-of-freedom displacement tables.

8. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 7, wherein the method comprises the following steps: the specific process of step S2 is as follows:

s2.1, after the harmonic reducer subjected to cutting processing is installed in a device for measuring radial deformation of a flexible gear tooth of the harmonic reducer, the position of a point laser displacement sensor is calibrated through a three-degree-of-freedom displacement table, so that the point laser displacement sensor can normally measure, and the point laser displacement sensor is fixed at the opening end of an observation opening on a rigid gear;

s2.2, opening an alternating current servo motor, enabling the alternating current servo motor to rotate, sequentially driving a first torque rotating speed sensor, a harmonic reducer, a second torque rotating speed sensor and a magnetic powder brake to rotate, and enabling a point laser displacement sensor to record data;

s2.3, moving the point laser displacement sensor by 0.5mm along the negative direction of the x axis through the three-degree-of-freedom displacement table;

and S2.4, repeating the steps S2.2 and S2.3 until the point laser displacement sensor moves to the closed end of the rigid wheel observation gap.

9. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 8, wherein the method comprises the following steps: the specific content of step S3 is as follows: and (3) carrying out noise reduction and optimization processing on data recorded by the point laser displacement sensor through MATLAB, finally obtaining an absolute value delta of the difference value between the maximum value and the minimum value of the radial deformation of the flexible wheel at each section position at the interval of 0.5mm along the x axis, and selecting the maximum value delta max and the minimum value delta min from a plurality of absolute values delta.

10. The method for optimizing the tooth profile of the rigid wheel of the harmonic reducer according to claim 9, wherein the method comprises the following steps: and substituting the extreme values delta max and delta min of the radial deformation of the flexible gear into a flexible gear motion trail equation, and obtaining the flexible gear motion trail through MATLAB simulation.

Background

The wave speed reducer has the characteristics of large transmission ratio, high transmission precision, compact structure, strong bearing capacity and the like, is suitable for application scenes with high precision, high load and small installation space, and is widely applied to the fields of aerospace, industrial robots and the like at present. The harmonic reducer is mainly composed of a wave generator, a rigid gear and a flexible gear. The wave generator is arranged in the flexible gear, and the flexible gear is expanded by the wave generator to generate deformation with the same shape as the wave. The partial teeth of the long shaft part of the flexible gear are contacted and meshed with the teeth of the rigid gear after being installed in the wave generator, and the partial teeth of the short shaft part are separated from the teeth of the rigid gear. The positions of the major and minor axes alternate with the rotation of the wave generator. Because of the extremely small difference of the number of teeth between the rigid gear and the flexible gear, the transmission with large reduction ratio can be realized according to the transmission ratio formula i ═ Zf-Zc)/Zf (Zf is the number of teeth of the flexible gear, and Zc is the number of teeth of the rigid gear).

The flexible gear and the rigid gear transmit motion and force through mutual meshing, and the tooth form of the rigid gear and the tooth form of the flexible gear play a decisive role in the meshing effect, so that the good tooth form can improve the transmission efficiency and the transmission precision, the stress between the meshing tooth surfaces is more uniform, the meshing performance is improved, and the service life of the gear is prolonged.

At present, an envelope method is mostly adopted for designing and optimizing the tooth form of the rigid wheel. The method comprises the steps of substituting a flexible gear parameter into a flexible gear motion track equation to obtain a flexible gear theoretical motion track, and obtaining an envelope curve of the rigid gear tooth profile based on the track. The method has the biggest problem that the substituted flexible gear parameters are obtained by adopting empirical values or a static measurement method, and the flexible gear parameters obtained by the two methods are inaccurate, so that the flexible gear motion track close to the real situation is difficult to obtain in a simulation mode, the transmission effect of the rigid gear tooth form obtained by enveloping and the flexible gear tooth form in the actual meshing process is poor, and even the phenomenon of flexible gear and rigid gear interference can be caused.

Disclosure of Invention

The invention aims to make up for the defects of the prior art and provides a method for optimizing the tooth profile of a rigid wheel of a harmonic reducer.

The invention is realized by the following technical scheme:

a method for optimizing the tooth profile of a rigid wheel of a harmonic reducer specifically comprises the following steps:

s1, forming an observation gap on the harmonic reducer rigid wheel through secondary cutting processing;

s2, mounting the cut harmonic reducer in a harmonic reducer flexible gear tooth radial deformation measuring device, and measuring by the harmonic reducer flexible gear tooth radial deformation measuring device to obtain flexible gear parameters of the harmonic reducer in a meshing motion state;

s3, processing the obtained flexbile gear parameters through MATLAB, substituting the processed flexbile gear parameters into a flexbile gear motion trail equation, and obtaining a motion trail highly fitting the real flexbile gear motion through MATLAB simulation;

and S4, taking a motion track envelope curve of the real flexspline motion, and fitting the envelope curve by adopting a plurality of sections of circular arcs based on the envelope curve to obtain the optimized rigid gear tooth shape.

The observation notch in the step S1 is in the shape of a sector, the centers of two arcs of the sector are both located on the central axis of the rigid wheel, the radii of the two arcs are respectively equal to the radius of the addendum circle of the rigid wheel and the radius of the outer contour of the rigid wheel, and the height of the sector is equal to the length of the gear of the rigid wheel.

The degree of the central angle corresponding to the fan-shaped body is 27.5 degrees.

The device for measuring the radial deformation of the flexible gear teeth of the harmonic reducer comprises a moving device body part and a parameter measuring part, wherein the moving device body part and the parameter measuring part are fixedly installed on a fixed base.

The moving device body part comprises an alternating current servo motor, an Oldham coupling I, a torque and rotating speed sensor I, an Oldham coupling II, a harmonic reducer after cutting processing, a flange coupling, a torque and rotating speed sensor II, an Oldham coupling III and a magnetic powder brake; the alternating current servo motor drives the first torque and speed sensor to rotate through the first crosshead shoe coupler, the first torque and speed sensor drives the harmonic reducer after cutting through the second crosshead shoe coupler to rotate, the harmonic reducer after cutting drives the second torque and speed sensor to rotate through the flange coupler, and the second torque and speed sensor drives the magnetic powder brake to rotate through the third crosshead shoe coupler.

Alternating current servo motor fixed mounting on motor unable adjustment base, torque speed sensor one and torque speed sensor two are fixed respectively on sensor fixing base one and sensor fixing base two, harmonic speed reducer ware fixed mounting after the cutting process is on speed reducer ware unable adjustment base, motor unable adjustment base, sensor fixing base one, sensor fixing base two, speed reducer ware unable adjustment base and magnetic powder brake respectively fixed mounting be in unable adjustment base is last.

The parameter measuring part comprises a first fixed support plate, a second fixed support plate, a three-degree-of-freedom displacement table, a displacement table fixing plate and a sensor fixing plate, the first fixed support plate and the second fixed support plate are symmetrically arranged in the middle of the fixed base in the width direction in parallel, a third fixed support plate is connected between the first fixed support plate and the second fixed support plate, the three-degree-of-freedom displacement table is formed by connecting three displacement tables in different displacement directions, the bottom of the three-degree-of-freedom displacement table is fixed at the central position of the displacement table fixing plate, and the displacement table fixing plate is fixed on the first fixed support plate and the second fixed support plate; the point laser displacement sensor is fixed at one end of the sensor fixing plate, and the sensor fixing plate is fixed on one of the three-degree-of-freedom displacement tables.

The specific process of step S2 is as follows:

s2.1, after the harmonic reducer subjected to cutting processing is installed in a device for measuring radial deformation of a flexible gear tooth of the harmonic reducer, the position of a point laser displacement sensor is calibrated through a three-degree-of-freedom displacement table, so that the point laser displacement sensor can normally measure, and the point laser displacement sensor is fixed at the opening end of an observation opening on a rigid gear;

s2.2, opening an alternating current servo motor, enabling the alternating current servo motor to rotate, sequentially driving a first torque rotating speed sensor, a harmonic reducer, a second torque rotating speed sensor and a magnetic powder brake to rotate, and enabling a point laser displacement sensor to record data; s2.3, moving the point laser displacement sensor by 0.5mm along the negative direction of the x axis through the three-degree-of-freedom displacement table;

and S2.4, repeating the steps S2.2 and S2.3 until the point laser displacement sensor moves to the closed end of the rigid wheel observation gap.

The specific content of step S3 is as follows: and (3) carrying out noise reduction and optimization processing on data recorded by the point laser displacement sensor through MATLAB, finally obtaining an absolute value delta of the difference value between the maximum value and the minimum value of the radial deformation of the flexible wheel at each section position at the interval of 0.5mm along the x axis, and selecting the maximum value delta max and the minimum value delta min from a plurality of absolute values delta.

And substituting the extreme values delta max and delta min of the radial deformation of the flexible gear into a flexible gear motion trail equation, and obtaining the flexible gear motion trail through MATLAB simulation.

The invention has the advantages that:

the method comprises the steps of measuring by using a device for measuring the radial deformation of the gear teeth of the flexible gear of the harmonic reducer to obtain real parameters of the flexible gear of the harmonic reducer in a meshing motion state, obtaining a motion track highly fitting real flexible gear motion through MATLAB simulation, taking an envelope curve of the motion track of the flexible gear, and adopting a multi-section arc fitting envelope curve based on the envelope curve to obtain the tooth profile of the optimized rigid gear. The invention provides a high-reliability method for optimizing the tooth profile of the rigid gear of the harmonic reducer, and the method has important significance for optimizing the tooth profile of the rigid gear of the harmonic reducer.

The invention can effectively optimize the tooth form of the rigid gear of the harmonic reducer, the backlash between the rigid gear and the flexible gear optimized by the invention is smaller, the meshing transmission efficiency is higher, the stress of the tooth surface is more uniform, the service life is longer, the flexible gear and the rigid gear have better meshing performance and better contact stress condition of the tooth surface, and the condition that the interference is generated between the flexible gear and the rigid gear due to the unreasonable tooth form design of the rigid gear is avoided.

Drawings

FIG. 1 is a schematic structural diagram of a device for measuring radial deformation of a flexible gear tooth of a harmonic reducer according to the present invention;

FIG. 2 is a flow chart of the method of the present invention;

FIG. 3 is an exploded view of the harmonic reducer after cutting;

FIG. 4 is a graph of the processed data;

FIG. 5 is a graph showing the motion trajectory simulation and envelope curve of the flexspline;

FIG. 6 is a schematic view of a parameter measurement section.

Detailed Description

As shown in fig. 2, a method for optimizing a tooth profile of a rigid wheel of a harmonic reducer specifically includes the following steps:

firstly, forming an observation notch 94 with a specific shape on a rigid wheel 93 of the harmonic reducer 9 through secondary cutting processing;

and secondly, mounting the processed harmonic reducer 9 into a device for measuring radial deformation of a flexible gear tooth of the harmonic reducer. Opening a device switch, calibrating the position of the point laser displacement sensor 10 through the three-degree-of-freedom displacement table 13, enabling the point laser displacement sensor 10 to measure normally, and fixing the point laser displacement sensor at the opening end of the rigid wheel observation opening 94;

thirdly, controlling the alternating current servo motor 2 to rotate through the controller 22, and returning and storing data recorded by the point laser displacement sensor 10 to the industrial computer 23;

fourthly, the point laser displacement sensor 10 is moved by 0.5mm along the negative direction of the x axis through the three-degree-of-freedom displacement platform 13;

fifthly, repeating the third step and the fourth step until the point laser displacement sensor 10 moves to the closed end of the rigid wheel observation gap 94;

and sixthly, performing noise reduction and optimization processing on the data on the industrial computer 23 through MATLAB, and visualizing the data to obtain the graph shown in FIG. 4. Solving the absolute value delta of the difference value between the maximum value and the minimum value of the radial deformation of the flexible wheel at each section position at intervals of 0.5mm along the x axis, and selecting the maximum value delta max and the minimum value delta min from a plurality of deltas;

step seven, substituting the extreme values delta max and delta min of the radial deformation of the flexible gear into a flexible gear motion trail equation, and obtaining a flexible gear motion trail through MATLAB simulation, as shown in figure 5;

eighthly, taking a motion track envelope curve of the flexible gear, as shown in fig. 5;

and step nine, fitting the envelope curve by using a plurality of sections of curves to obtain the optimized tooth profile of the rear rigid wheel.

As shown in fig. 1, the device for measuring radial deformation of a flexible gear tooth of a harmonic reducer comprises a body part of a movement device and a parameter measuring part.

The exercise device body portion: the alternating current servo motor 2 is fixedly arranged on a motor fixing base 3 fixed on the fixing base 1, a first torque and speed sensor 5 is driven to rotate through a first crosshead shoe coupling 4, the first torque and speed sensor 5 drives a cut harmonic speed reducer 9 to rotate through a second crosshead shoe coupling 7, the cut harmonic speed reducer 9 drives a second torque and speed sensor 16 to rotate through a flange coupling, and the second torque and speed sensor 16 drives a magnetic powder brake 19 to rotate through a third crosshead shoe coupling 18; the motor fixing base 3 is positioned in the middle of the fixing base 1 in the width direction, the distance from the length direction to the port of the fixing base 1 is 200mm, the bottom surface of the motor fixing base 3 is overlapped with the upper surface of the fixing base 1, and 2 sliding block nut bolt combination arrays of M20 which are uniformly distributed at a distance of 200mm in the transverse direction and 2 uniformly distributed at a distance of 100mm in the longitudinal direction are fixed on the fixing base 1; the alternating current servo motor 2 is fixed at the center of the upper end of the motor fixing base 3 through 4 square evenly distributed bolts with the interval of 80 mm; the first torque and rotation speed sensor 5 is connected with the alternating current servo motor 2 through a first crosshead shoe coupling 4 and is concentric with the first crosshead shoe coupling 4, the first torque and rotation speed sensor 5 is fixed on a first sensor fixing base 6 through 4 square uniformly distributed bolts with the spacing of 100mm, the first sensor fixing base 6 is fixed in the middle of the fixing base 1 in the width direction through 4 square uniformly distributed slide block nut bolt arrays with the spacing of 200mm, and the distance from the fixing base 1 to the port in the length direction is 500 mm; the input end of the harmonic reducer 9 after cutting is connected with a first torque and speed sensor 5 through a cross-slide coupling II 7, the three parts are concentric, the harmonic reducer 9 after cutting is fixed in the middle of the upper end of a reducer fixing base 8 through a 360-degree bolt and screw hole array combination with the radius of 80mm, the reducer fixing base 8 is located in the middle of the width direction of a fixing base 1, the distance from the length direction to the port of the fixing base 1 is 800mm, the bottom surface of the reducer fixing base 8 is overlapped with the upper surface of the fixing base 1, 2 slide block nut and bolt combination arrays of M20 are uniformly distributed in the transverse direction at the distance of 200mm, and 2 slide block nut and bolt combination arrays of M20 are uniformly distributed in the longitudinal direction at the distance of 100mm and fixed on the fixing base 1; a second torque and speed sensor 16 is connected with the output end of the harmonic speed reducer 9 after cutting processing through a flange coupling 15, the three are concentric, the second torque and speed sensor 16 is fixed on a second sensor fixing base 17 through 4 square uniformly distributed bolts with the spacing of 100mm, the second sensor fixing base 17 is fixed in the middle of the fixing base 1 in the width direction through 4 square uniformly distributed slider nut bolt arrays with the spacing of 200mm, and the distance from the fixing base 1 in the length direction is 1000 mm; the magnetic powder brake 19 is connected with the second torque and rotation speed sensor 16 through the third Oldham coupling 18, the magnetic powder brake 19 is positioned in the middle of the fixed base 1 in the width direction, the distance from the length direction to the port of the fixed base 1 is 1500mm, the bottom of the magnetic powder brake 19 is superposed with the upper surface of the fixed base 1, 2 magnetic powder brakes are transversely and uniformly distributed at a distance of 500mm, and 2 magnetic powder brakes are longitudinally and uniformly distributed at a distance of 200mm and are fixed on the fixed base 1 through M20 slide block nut-bolt combined arrays; the magnetic particle brake 19 can be used to simulate different loads.

The torque and rotation speed sensor is arranged to ensure that the input working condition of the harmonic reducer to be measured reaches an ideal standard and finally ensure the accuracy of the measurement result. The method has the functions of detecting whether the actual rotating speed of the input end of the harmonic reducer is consistent with the output rotating speed of the servo motor or not and detecting whether the torque of the output end of the harmonic reducer is the same as the direction torque input by the magnetic powder brake or not. Two torque-speed sensor embodiments: after the comprehensive power supply is started, the torque and rotation speed sensor enters a working state and feeds back real-time torque and rotation speed parameters of the input end and the output end of the harmonic reducer in real time through a display screen of the industrial computer.

As shown in fig. 6, the parameter measurement section: the first fixed support plate 11 and the second fixed support plate 20 are symmetrically arranged in the middle of the fixed base 1 in the width direction, the distance between the first fixed support plate 11 and the second fixed support plate 20 in the width direction is 600mm, and the distance between the centers of the two support plates in the length direction is 1000mm from the port of the fixed base 1; the third fixed support plate 21 is connected between the first fixed support 11 and the second fixed support plate 20, the first fixed support plate 11 and the second fixed support plate 20 are both H-shaped, and the bottoms of the first fixed support 11 and the second fixed support plate 20 are both connected with aluminum frames with the length of 600 mm; the three-degree-of-freedom displacement table 13 is formed by connecting three displacement tables in different displacement directions, the bottom of the three-degree-of-freedom displacement table 13 is fixed at the center position of a displacement table fixing plate 14 through 4 square uniformly distributed bolt and screw hole array combinations with the distance of 50mm, and the displacement table fixing plate 14 is fixed on a first fixed support plate 11 and a second fixed support plate 20 through M8 slide block nut and bolt array combinations which are uniformly distributed for 2 in the transverse direction with the distance of 580mm and uniformly distributed for 2 in the longitudinal direction with the distance of 80 mm; the point laser displacement sensor 10 is fixed at one end of a sensor fixing plate 12 through 4 square uniformly distributed bolt and screw hole array combinations with the interval of 80mm, and the sensor fixing plate 12 is fixed on a three-degree-of-freedom displacement table through 4 square uniformly distributed bolt and screw hole array combinations with the interval of 80 mm.

As shown in fig. 3, the harmonic reducer includes a wave generator 91, a flexible gear 92, and a steel gear 93, the rigid gear 93 of the harmonic reducer is processed by secondary cutting to form an observation notch 94 of a specific shape, the observation notch 94 is shaped as a sector, centers of two arcs of the sector are both located on a central axis of the rigid gear, radii of the two arcs are respectively equal to a radius of an addendum circle of the rigid gear and a radius of an outer contour of the rigid gear, a height of the sector is equal to a length of the gear of the rigid gear, and a central angle corresponding to the sector is 27.5 degrees.