End-meshing harmonic reducer with adjustable backlash and stiffness, test bench and application thereof

Abstract

This invention relates to the field of automated equipment manufacturing technology, specifically to an end-meshing harmonic reducer with adjustable backlash and stiffness, a test bench, and their applications. The reducer comprises an input end base, an input shaft, bearings, a bearing housing, a shaft end retaining ring, a single-wave end face cam, a universal ball bearing, a sleeve, a spring, a slide rail, a grooved wheel, a slider, a live gear, a rigid wheel, an output end base, an output shaft, a snap ring, shims, and a housing. The end face cam drives the live gear to mesh with the rigid wheel, thereby driving the grooved wheel to transmit power. Adjustments to the meshing backlash, stiffness, and center distance of the transmission components can be achieved through shim and bolt adjustment. The input and output shaft angles and input / output torques are sensed by an encoder and a torque sensor, respectively, and analyzed by a computer to generate angular velocity and torque curves. Finally, the influence of meshing parameters on transmission performance is verified through motion law change trend analysis.

Description

Technical fields:

[0001] This invention relates to the field of automated equipment manufacturing technology, specifically to an end-meshing harmonic reducer and test bench with adjustable backlash and stiffness that can overcome the defects of traditional harmonic gears such as easy fatigue failure of the flexible wheel and weak load-bearing capacity, and can be applied to the expected adjustment function to explore the influence of multi-parameter coupling on the transmission performance of the end-meshing gear system. Background technology:

[0002] As aircraft continue to operate on the ground and conduct external exploration, the nature of the missions is becoming increasingly complex, long-term, and unpredictable. The transmission systems of important joints such as robotic arms, deployment and release mechanisms, and servo drive mechanisms all adopt compact harmonic reducers developed in-house.

[0003] Traditional harmonic gear transmission devices use a wave generator with a specific geometry to force a thin-walled flexible wheel to undergo periodic deformation, continuously engaging, disengaging, and meshing with a rigid wheel to generate relative motion. However, the thin-walled flexible wheel has low stiffness, small tooth module, and low load-bearing capacity. During loaded driving and variable load meshing, it is prone to generating additional stress, leading to deformation of the flexible wheel. Its periodic deformation and vibration can cause fatigue failure, thus affecting the operating state of the transmission system. Summary of the Invention:

[0004] This invention addresses the shortcomings and deficiencies of existing technologies by proposing a high-performance end-meshing harmonic reducer and an end-meshing harmonic reducer test bench that enables adjustment of backlash and stiffness. Based on this, a standardized comprehensive experimental platform is built to achieve the expected adjustment functions, thereby exploring the influence of multi-parameter coupling on the transmission performance of end-meshing gear systems.

[0005] This invention achieves its purpose through the following measures:

[0006] An end-meshing harmonic reducer with adjustable backlash and stiffness is characterized by comprising an input end base (18), an input shaft (19), a bearing (20), a bearing housing (21), a shaft end retaining ring (22), a single-wave end face cam (23), a universal ball bearing (24), a sleeve (25), a spring (26), a slide rail (27), a grooved wheel (28), a slider (29), a movable gear (30), a rigid wheel (31), an output end base (32), an output shaft (33), a snap ring (34), a washer (35), and a housing (36); the input end base (18) and the bearing housing (21) are fixedly connected by bolts; the input shaft (19) is connected to the bearing housing (21) and the input end base (18) by the bearing (20). Axial positioning is achieved through the shoulder and bearing seat (21) holes using snap rings; the single-wave end face cam (23) and the input shaft (19) are connected to the hub by a flat key; the shaft end retaining ring (22) is fixed to the input shaft (19) at the end face by a tapered bolt, thus completing the axial positioning of the single-wave end face cam (23); the output shaft (33) and the output end base (32) are connected by bearings, and axial positioning is achieved through a shaft snap ring (34); the rigid wheel (31) and the output end base (32) are fixed to the end face by bolts, aligning the protrusion of the output end base (32) with the rigid wheel groove, thus completing the circumferential positioning of the rigid wheel (31); the grooved wheel (28) and the output shaft (33) are connected to the hub by a flat key, and the slide rail (27) The groove of the grooved wheel (28) is embedded in the groove of the grooved wheel (28), and the two are fixed together by bolts; the shaft end retaining ring (22) is fixed to the output shaft (33) at the end face by tapered bolts to realize the axial positioning of the grooved wheel (28); the movable tooth (30) and the sleeve (25) are fixed together by the thread on the surface of the sleeve, the universal ball bearing (24) is embedded in the sleeve (25), the slider (29) and the movable tooth (30) are fixed together by bolts, the movable tooth (30), the sleeve (31), the universal ball bearing (24), and the slider (29) together form the movable tooth assembly, the universal ball bearing (24) realizes the rolling friction between the movable tooth assembly and the single-wave end face cam, and the slider (29) is placed in the slide rail (27) to realize the sliding of the movable tooth assembly, the slider (29) and the slide rail (27) 27) All are made of friction-reducing materials to reduce friction and noise. The spring (26) is arranged around the live tooth (30) and axially positioned by the end face of the sleeve (25). Therefore, the live tooth assembly is in constant contact with the single-wave end face cam (23) and moves axially with its rotation. The tooth profiles of the live tooth (30) and the rigid wheel (31) are all positive helical surfaces, and the top of the teeth is trimmed to improve the meshing characteristics. The input end base (18), the output end base (32) and the housing (36) are fixed together by long bolts. By changing the number of shims (35), the center distance between the input end base (18), the output end base (32) and the housing (36) is adjusted, thereby changing the meshing overlap of the teeth. The meshing clearance and overall stiffness of the live tooth (30) change accordingly.

[0007] In this invention, due to the large number of live teeth (30), the grooved wheel (28) requires a large number of slots. At the same time, interference is likely to occur between adjacent live teeth (30), which will inevitably aggravate the vibration of movement. Therefore, the live teeth (30) are removed by a tooth-removal method. In order to avoid the phenomenon of insufficient load-bearing capacity due to the reduction of the number of meshing teeth at the same time, each group of live teeth (30) is provided with three gear teeth.

[0008] In this invention, the rigid wheel (31) has 50 teeth and the theoretical total number of teeth of the live tooth (30) is 49. Therefore, the transmission ratio is 50, which is the ratio of the number of teeth of the rigid wheel and the difference between the number of teeth of the rigid wheel (31) and the theoretical total number of teeth of the live tooth (30). Since the theoretical total number of teeth of the live tooth (30) is slightly smaller than the number of teeth of the rigid wheel (31), the teeth of the live tooth (30) always enter the tooth groove of the next rigid wheel (31) after each cycle of movement. The interlocking meshing and power transmission functions are thus realized.

[0009] The working principle of the mid-end meshing harmonic reducer of the present invention is as follows: When the single-wave end face cam (23) rotates clockwise, it pushes the live tooth (30) assembly to move axially. The live tooth (30) moving to the right along the contour of the single-wave end face cam (23) gradually engages with the teeth of the rigid wheel (31). The live tooth assembly is forced to contact the contour surface of the cam end face under the action of the spring. Therefore, the live tooth (30) moving to the left along the contour of the single-wave end face cam (23) gradually disengages from the teeth of the rigid wheel (31). Since the rigid wheel (31) is fixed to the machine base, the live tooth (30) is subjected to the reaction force of the rigid wheel (31) and thus moves upward or downward along the inclined surface of the teeth of the rigid wheel (31), and is forced to complete the composite motion of axial movement and circumferential rotation, thereby transmitting power to the grooved wheel (28), and finally driving the output shaft connected to the grooved wheel to output power.

[0010] The present invention also provides a test bench for an end-meshing harmonic reducer with adjustable backlash and stiffness, characterized in that it includes a cast iron perforated plate workbench (1), an aluminum profile (2), a motor base plate (3), a stepper motor (4), an angle iron (5), an angle bracket (6), a coupling (7), a transmission shaft (8), a flange connecting plate (9), an encoder flange (10), an angle encoder (11), an end-meshing harmonic reducer with adjustable backlash and stiffness as described above (12), a reducer base plate (13), a torque sensor connecting flange (14), a torque sensor (15), a magnetic powder brake (16), and a brake connecting flange (17);

[0011] The cast iron perforated plate workbench (1) and the aluminum profile (2) are fixedly connected by bolts and washers. The length of the aluminum profile (2) can be selected according to the specific experimental conditions, and the relative position can be determined through the through hole of the workbench. The aluminum profile (2) has a scale, and the specific center distance can be adjusted by aligning the experimental equipment base plate with the scale. The motor base plate (3) and the reducer base plate (13) are fixedly connected to the aluminum profile (2) by T-bolts and nuts, and the T-nuts are placed in the sliding groove of the aluminum profile (2). The sliding motion can determine the relative positions of the motor base plate (3) and the reducer base plate (13) and align them with the required scale; the stepper motor (4) is fixed to the motor base plate (3) by angle iron (5), and the vertical height is determined by the position of the bolt in the long hole of the angle iron (5) to adjust the coaxiality of the system; the flange connecting plate (9), the torque sensor connecting flange (14), and the brake connecting flange (17) are all fixed to the aluminum profile (2) by angle brackets and T-bolts, and the relative positions of the flange connecting plate (9), the torque sensor connecting flange (14), and the brake connecting flange (17) can be determined by the sliding motion of the T-nut in the groove of the aluminum profile (2) and align them with the required scale; the flange connecting plate (9) is fixed to the encoder flange (10) by bolts; the angle encoder (11) consists of a fixed end and a movable end, and its fixed end is fixed to the encoder flange (10) by bolts; the side clearance and stiffness adjustable end meshing harmonic reducer (12) is fixed to the reducer base plate (13) and the reducer base plate (14). 3) The system is fixed by angle iron (5), and the vertical height is determined by the position of bolts in the holes of angle iron (5) to adjust the coaxiality of the system; the brake connecting flange (17) is fixed to the aluminum profile (2) by angle bracket (6), and fixed to the magnetic powder brake (16) by bolts; the transmission shaft (8) is fixed to the stepper motor (4), the end meshing harmonic reducer (12) with adjustable backlash and stiffness, the magnetic powder brake (16), and the torque sensor (15) by coupling (7) to transmit power.

[0012] In this invention, the stepper motor (4), magnetic powder brake (16), angle encoder (11) and torque sensor (15) are all powered by a storage battery. The storage battery is placed on the upper part of the cast iron perforated plate and can be charged through the interface current. The speed and torque characteristics of the stepper motor (4) are adjusted by a controller and a pulse generator. The controller and pulse generator are placed on the upper part of the cast iron perforated plate.

[0013] The experimental process of the experimental platform proposed in this invention is as follows: The battery provides power to the stepper motor, magnetic powder brake, angle encoder, torque sensor and their control and debugging components. The stepper motor controller adjusts the stepper motor microstepping and torque characteristics. The pulse generator sends pulse signals to the stepper motor and adjusts the duty cycle. The stepper motor then inputs power at a certain speed. The power is transmitted to the end-meshing harmonic reducer through intermediate links such as the drive shaft and coupling. The end-meshing harmonic reducer then realizes the staggered meshing function to amplify the torque and transmit the power to the torque sensor. Finally, the magnetic powder brake provides a variable output load. Both the input and output drive shafts are equipped with absolute angle encoders, which can continuously measure the real-time angle information of the input and output ends for multiple turns and transmit the signals to the host computer to generate angle curves. After data processing, angular velocity and angular acceleration curves are obtained as the basis for dynamic performance analysis of the end-meshing harmonic reducer. The encoder interface is connected to the debugger to determine and correct the initial state. The torque sensor is placed between the output encoder and the magnetic powder brake, which can measure the output torque information in real time and transmit the signals to the host computer. The magnetic powder brake interface is connected to the controller, which can adjust the load torque value to realize the data acquisition function under variable working conditions. Adjusting the number of shims in the end-meshing harmonic reducer can adjust the center distance between the rigid wheel, the live gear assembly, and the single-wave end face cam to adjust the tooth meshing overlap. The live gear meshing backlash and overall stiffness change accordingly. Adjusting the relative position between the base plate and the flange and the aluminum profile changes the center distance of the experimental equipment, which changes the overall stiffness of the experimental platform. Data from multiple sets of structural parameters under various working conditions are measured and the signals are collected to the host computer. Data processing yields the transmission error, vibration characteristics, and torque characteristics of the end-meshing harmonic deceleration device with variable parameters such as gear meshing backlash, overall stiffness, and experimental platform center distance. This allows us to understand the influence mechanism of structural parameters on the performance parameters of the end-meshing harmonic deceleration device.

[0014] The experimental platform proposed in this invention is adjustable, adopts a series layout, and the experimental equipment is interchangeable. The required type of sensor can be installed or replaced at any intermediate link. Different types of motors, reducers and brakes can be adjusted to meet certain coaxiality and center distance, and have sufficient overall rigidity. Attached image description:

[0015] Figure 1 This is a schematic diagram of the experimental setup for the mid-end meshing harmonic reducer of this invention.

[0016] Figure 2 This is a schematic diagram of the structure of the mid-end meshing harmonic deceleration device of the present invention.

[0017] Figure 3 This refers to the structure of the input terminal base and bearing housing in this invention.

[0018] Figure 4This is a schematic diagram of the input shaft and single-wave end face cam structure in this invention.

[0019] Figure 5 This is a schematic diagram of the rigid wheel and the output end base structure in this invention.

[0020] Figure 6 This is a schematic diagram of the grooved wheel, slide rail and output shaft structure in this invention.

[0021] Figure 7 This is a schematic diagram of the movable tooth assembly in this invention.

[0022] Figure 8 This is a schematic diagram of the transmission principle of the present invention.

[0023] Figure 9 This is a schematic diagram of the experimental principle of the experimental platform in this invention.

[0024] Reference numerals: Cast iron perforated plate workbench (1), aluminum profile (2), motor base plate (3), stepper motor (4), angle iron (5), angle bracket (6), coupling (7), transmission shaft (8), flange connecting plate (9), encoder flange (10), angle encoder (11), end meshing harmonic reducer (12), reducer base plate (13), torque sensor connecting flange (14), torque sensor (15), magnetic powder brake (16), brake connecting flange (17), input end base (18), input shaft (19), bearing (20), bearing seat (21), shaft end retaining ring (22), single wave end face cam (23), universal ball bearing (24), sleeve (25), spring (26), slide rail (27), grooved wheel (28), slider (29), live gear (30), rigid wheel (31), output end base (32), output shaft (33), snap ring (34), gasket (35), housing (36). Detailed implementation method:

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0026] This invention provides an end-meshing harmonic reducer and experimental platform capable of adjusting backlash and stiffness. An end-face cam drives a movable gear to mesh with a rigid wheel, thereby driving a grooved wheel to transmit power. Adjustments to the meshing backlash, stiffness, and center distance of the transmission components can be made using shims and bolts. Encoders and torque sensors detect the input and output shaft angles and input / output torques, respectively, and computer analysis generates angular velocity and torque curves. Finally, the influence of meshing parameters on transmission performance is verified through motion law change trend analysis.

[0027] Includes a cast iron perforated plate workbench (1), aluminum profile (2), angle iron (5), stepper motor (4), motor base plate (3), controller, drive shaft (8), coupling (7), torque sensor connecting flange (14), angle code (6), end meshing harmonic reducer (12), reducer base plate (13), magnetic powder brake (16), brake connecting flange (17), angle encoder (11), encoder flange (10), flange connecting plate (9), and torque sensor (15);

[0028] The cast iron perforated plate workbench (1) is fixedly connected to the aluminum profile (2), and their relative positions can only be determined by fixing them through holes; the aluminum profile (2) has a scale, which can realize the adjustment of the center distance of the experimental equipment; the torque sensor connecting flange (14), flange connecting plate (9), and brake connecting flange (17) are all fixedly connected to the aluminum profile (2), and are connected by T-bolts through angle brackets (6), and their relative positions are determined by the bolt positions; the motor base plate (3) and reducer base plate (13) are all fixedly connected to the aluminum profile (2) through T-bolts and nuts, and their relative positions are determined by the bolt positions;

[0029] The encoder flange (10) is bolted to the flange connecting plate (9) to connect the fixed end of the angle encoder (11); the stepper motor (4) is bolted to the motor base plate (3) by angle iron (5), and the vertical height is determined by the position of the bolt in the angle iron hole to adjust the coaxiality of the system; the end meshing harmonic reducer (12) is bolted to the reducer base plate (13) by angle iron (5), and the vertical height is determined by the position of the bolt in the angle iron hole to adjust the coaxiality of the system; the brake connecting flange (17) is bolted to the aluminum profile (2) by angle bracket (6), and bolted to the magnetic powder brake (16); the drive shaft (8) is connected to the stepper motor (4), the end meshing harmonic reducer (12), the magnetic powder brake (16), and the torque sensor (15) by coupling (7) to transmit power;

[0030] The battery is placed on the upper part of the cast iron perforated plate and provides power to the stepper motor (4), controller, magnetic powder brake (16), angle encoder (11) and torque sensor (15), and is charged through a preset interface; the controller is placed on the upper part of the cast iron perforated plate and adjusts the speed and torque characteristics of the stepper motor (4) through a pulse generator.

[0031] Among them, the end meshing harmonic reducer (12) includes an input end base (18), an output end base (32), a housing (36), a rigid wheel (31), a grooved wheel (28), a single-wave end face cam (23), a live gear (30), a slide rail (27), a slider (29), a sleeve (25), a universal ball bearing (24), a spring (26), a bearing (20), an input shaft (19), an output shaft (33), a snap ring (34), a bearing seat (21), a gasket (35), and a shaft end retaining ring (22);

[0032] The bearing housing (21) is fixedly connected to the input end base (18); the input shaft (19) is connected to the bearing housing (21) and the input end base (18) through bearings, and is axially positioned by a shoulder and a snap ring; the single-wave end face cam (23) is connected to the input shaft (19) through a flat key to complete the hub connection;

[0033] The shaft end retaining ring (22) is fixed to the input shaft at the end face by a tapered bolt, thereby completing the axial positioning of the single-wave end face cam (23); the output shaft (33) is connected to the output end base (32) by a bearing and is axially positioned by a snap ring (34); the rigid wheel (31) is fixed to the output end base (32) at the end face, and the rigid wheel (31) is circumferentially positioned by the protrusion of the output end base (32) and the rigid wheel groove;

[0034] The grooved wheel (28) is connected to the output shaft via a flat key; the shaft end retaining ring (22) is fixed to the output shaft at the end face via tapered bolts to achieve axial positioning of the grooved wheel; the movable tooth is fixed to the slider and is placed in the slide rail for sliding; the movable tooth, sleeve, and universal ball bearing are fixed together, with a spring arranged around the movable tooth and axially positioned by the end face of the sleeve. The input end base, output end base, and housing are fixed together by long bolts, and the wheelbase of the three is adjusted by shims to achieve adjustment of the movable tooth meshing backlash and stiffness.

[0035] This invention employs an end-meshing configuration, using a single-wave end-face cam as the input element and a grooved wheel as the output element. Rigid elements are used to improve load-bearing capacity and overcome inherent fatigue failure defects, achieving interlocking meshing of the live gears to complete power transmission. The slider and slide rail are both made of anti-friction materials. The live gear assembly contacts the single-wave end-face cam via a universal ball bearing, significantly reducing transmission friction resistance and improving lifespan. Both the rigid wheel teeth and the live gear teeth undergo profile modification, improving transmission smoothness and preventing meshing interference. Springs are arranged around the live gear to ensure contact between the live gear assembly and the cam. The structural parameters are variable; the wheelbase between the rigid wheel, the live gear assembly, and the single-wave end-face cam is adjusted by the number of shims. To achieve adjustment of the meshing backlash and stiffness of the live gear, both the input and output shafts adopt a double-bearing support method to improve the transmission stiffness and stability of the end-meshing harmonic reducer. The end face cam has a wave number of 1, so the live gear assembly completes one reciprocating motion for each rotation of the end face cam. The difference between the number of teeth of the rigid wheel and the theoretical total number of teeth of the live gear is equal to the wave number of the end face cam, and the transmission ratio is equal to the number of teeth of the rigid wheel. The end face profile of the end face cam, the tooth profile of the live gear, and the tooth profile of the rigid wheel are all positive helical surfaces. It can measure performance parameters under multiple working conditions and multiple coupling factors. When the structural parameters change, the operating state of the end-meshing harmonic reducer can be uniquely determined, satisfying the real-time and synchronization requirements of multiple sets of sensor signals under the same working condition.

[0036] Example 1:

[0037] This example provides an experimental platform for end-meshing harmonic reducers that allows for adjustment of backlash and stiffness, such as... Figure 1 As shown, the experimental platform for the end-meshing harmonic reducer that can realize the adjustment of backlash and stiffness includes a cast iron perforated plate workbench (1), aluminum profile (2), motor base plate (3), stepper motor (4), angle iron (5), angle bracket (6), coupling (7), transmission shaft (8), flange connecting plate (9), encoder flange (10), angle encoder (11), end-meshing harmonic reducer device (12), reducer base plate (13), torque sensor connecting flange (14), torque sensor (15), magnetic powder brake (16), and brake connecting flange (17).

[0038] The cast iron perforated plate workbench (1) and the aluminum profile (2) are fixedly connected by bolts and washers. The length of the aluminum profile (2) can be selected according to the specific experimental conditions and the relative position can be determined through the through hole of the workbench. The aluminum profile (2) has a scale, and the specific center distance can be adjusted by aligning the experimental equipment base plate with the scale. The motor base plate (3) and the reducer base plate (13) are fixedly connected to the aluminum profile (2) by T-bolts and nuts. The relative position of the motor base plate (3) and the reducer base plate (13) can be determined by sliding the T-nut in the slide groove of the aluminum profile (2) and aligning it with the required scale. The stepper motor (4) is fixedly connected to the motor base plate (3) by angle iron (5). The vertical height is determined by the position of the bolt in the long hole of the angle iron (5) to adjust the coaxiality of the system. The flange connecting plate (9), the torque sensor connecting flange (14), and the brake connecting flange (17) are all fixedly connected to the aluminum profile (2) by angle brackets and T-bolts. The sliding of the nut in the groove of the aluminum profile (2) determines the relative position of the flange connecting plate (9), the torque sensor connecting flange (14), and the brake connecting flange (17) and aligns them with the required scale; the flange connecting plate (9) is fixed to the encoder flange (10) by bolts; the angle encoder (11) consists of a fixed end and a movable end, and its fixed end is fixed to the encoder flange (10) by bolts; the end meshing harmonic deceleration device (12) is fixed to the reducer base plate (13) by angle iron (5), and the vertical height is determined by the position of the bolt in the hole of the angle iron (5) to adjust the coaxiality of the system; the brake connecting flange (17) is fixed to the aluminum profile (2) by angle bracket (6) and fixed to the magnetic powder brake (16) by bolts; the drive shaft (8) is fixed to the stepper motor (4), the end meshing harmonic deceleration device (12), the magnetic powder brake (16), and the torque sensor (15) by coupling (7) to transmit power.

[0039] The structure of the end-meshing harmonic reducer (12) in this example is as follows: Figure 2 As shown, its components include an input end base (18), an input shaft (19), a bearing (20), a bearing housing (21), a shaft end retaining ring (22), a single-wave end face cam (23), a universal ball bearing (24), a sleeve (25), a spring (26), a slide rail (27), a grooved wheel (28), a slider (29), a movable gear (30), a rigid wheel (31), an output end base (32), an output shaft (33), a snap ring (34), a washer (35), and a housing (36); the input end base (18) and the bearing housing (21) are fixedly connected by bolts, and their structures are as follows. Figure 3 As shown; the input shaft (19) is connected to the bearing housing (21) and the input end base (18) through the bearing (20), and is axially positioned by a snap ring through the shaft shoulder and the hole of the bearing housing (21);

[0040] The single-wave end face cam (23) and the input shaft (19) are connected to the hub via a flat key, and their structures are as follows: Figure 4 As shown; the shaft end retaining ring (22) is fixed to the input shaft (19) at the end face by a tapered bolt, completing the axial positioning of the single-wave end face cam (23); the output shaft (33) is connected to the output end base (32) by a bearing, and the axial positioning is completed by a shaft retaining ring (34); the rigid wheel (31) is fixed to the output end base (32) at the end face by bolts, and aligning the protrusion of the output end base (32) with the rigid wheel groove can enable the rigid wheel (31) to complete the circumferential positioning. The structures of the two are as follows. Figure 5 As shown; the grooved wheel (28) and the output shaft (33) are connected by a flat key, and the slide rail (27) is embedded in the groove of the grooved wheel (28). The two are fixed together by bolts. The structure of the three is as follows. Figure 6 As shown; the shaft end retaining ring (22) is fixed to the output shaft (33) at the end face by a tapered bolt to achieve axial positioning of the grooved wheel (28);

[0041] The movable tooth (30) and the sleeve (25) are fixedly connected by threads on the surface of the sleeve. The universal ball bearing (24) is embedded in the sleeve (25). The slider (29) and the movable tooth (30) are fixedly connected by bolts. The movable tooth (30), the sleeve (31), the universal ball bearing (24), and the slider (29) together form the movable tooth assembly. The structure of each part is as follows: Figure 7 As shown, the rolling friction between the live gear assembly and the single-wave end face cam can be achieved by the universal ball bearing (24). The sliding of the live gear assembly can be achieved by placing the slider (29) in the slide rail (27). The slider (29) and the slide rail (27) are both made of friction-reducing material to reduce friction and noise. The spring (26) is arranged around the live gear (30) and is axially positioned by the end face of the sleeve (25). Therefore, the live gear assembly is always in contact with the single-wave end face cam (23) and moves axially with its rotation.

[0042] The tooth profiles of the live teeth (30) and the rigid wheel (31) are all positive helical surfaces, and the top of the teeth is trimmed to improve the meshing characteristics. Since there are many live teeth (30), the grooved wheel (28) needs to have a large number of grooves. At the same time, interference is likely to occur between adjacent live teeth (30), and the vibration of the movement will inevitably be aggravated. Therefore, the live teeth (30) are removed by tooth removal. In order to avoid the phenomenon of insufficient load-bearing capacity due to the reduction of the number of meshing teeth at the same time, each group of live teeth (30) is provided with three teeth in this embodiment. The input end base (18), the output end base (32) and the housing (36) are fixed together by long bolts. By changing the number of shims (35), the center distance of the three can be adjusted to change the meshing overlap of the teeth. The meshing clearance and overall stiffness of the live teeth (30) change accordingly.

[0043] The working principle of the end-meshing harmonic reducer (12) is as follows: Figure 8As shown, when the single-wave end face cam (23) moves in the direction shown in the figure, i.e., rotates clockwise in the left view, it pushes the movable tooth (30) assembly to move axially. The movable tooth (30) moving to the right along the contour of the single-wave end face cam (23) gradually engages with the teeth of the rigid wheel (31). Under the action of the spring, the movable tooth assembly is forced to contact the contour surface of the cam end face. Therefore, the movable tooth (30) moving to the left along the contour of the single-wave end face cam (23) gradually disengages from the teeth of the rigid wheel (31). Since the rigid wheel (31) is fixed to the machine base, the movable tooth (30) is subjected to the reaction force of the rigid wheel (31) and moves along the inclined surface of the teeth of the rigid wheel (31). Upward or downward, it is forced to complete a composite motion of axial movement and circumferential rotation, thereby transmitting power to the grooved wheel (28), and finally driving the output shaft connected to the grooved wheel to output power. In this embodiment, the number of teeth of the rigid wheel (31) is 50, and the theoretical total number of teeth of the live tooth (30) is 49, so the transmission ratio is 50, that is, the ratio of the number of teeth of the rigid wheel and the difference between the number of teeth of the rigid wheel (31) and the theoretical total number of teeth of the live tooth (30). Since the theoretical total number of teeth of the live tooth (30) is slightly smaller than the number of teeth of the rigid wheel (31), the teeth of the live tooth (30) always enter the tooth groove of the next rigid wheel (31) after each cycle of movement, and the functions of tooth meshing and power transmission are thus realized.

[0044] The stepper motor (4), magnetic powder brake (16), angle encoder (11), and torque sensor (15) are all powered by a battery, which is placed on the upper part of the cast iron perforated plate and can be charged through the interface current. The speed and torque characteristics of the stepper motor (4) are adjusted by a controller and a pulse generator, which are placed on the upper part of the cast iron perforated plate.

[0045] The experimental procedure is as follows Figure 9As shown, the battery provides power to the stepper motor, magnetic powder brake, angle encoder, torque sensor, and their control and debugging components. The stepper motor controller adjusts the stepper motor's microstepping and torque characteristics, and the pulse generator sends pulse signals to the stepper motor and adjusts the duty cycle. The stepper motor then inputs power at a certain speed, which is transmitted to the end-meshing harmonic reducer through intermediate links such as the drive shaft and coupling. The end-meshing harmonic reducer then realizes the staggered meshing function to amplify the torque and transmit the power to the torque sensor. Finally, the magnetic powder brake provides a variable output load. Both the input and output drive shafts are equipped with absolute angle encoders, which can continuously measure the real-time angle information of the input and output ends for multiple turns and transmit the signals to the host computer to generate angle curves. After data processing, angular velocity and angular acceleration curves are obtained as the basis for dynamic performance analysis of the end-meshing harmonic reducer. The encoder interface is connected to the debugger to determine and correct the initial state. The torque sensor is placed between the output encoder and the magnetic powder brake, which can measure the output torque information in real time and transmit the signals to the host computer. The magnetic powder brake interface is connected to the controller, which can adjust the load torque value to realize the data acquisition function under variable working conditions. Adjusting the number of shims in the end-meshing harmonic reducer can adjust the center distance between the rigid wheel, the live gear assembly, and the single-wave end face cam to adjust the tooth meshing overlap. The live gear meshing backlash and overall stiffness change accordingly. Adjusting the relative position between the base plate and the flange and the aluminum profile changes the center distance of the experimental equipment, which changes the overall stiffness of the experimental platform. Data from multiple sets of structural parameters under various working conditions are measured and the signals are collected to the host computer. Data processing yielded the transmission error, vibration characteristics, and torque characteristics of the end-meshing harmonic reducer, based on variable parameters such as gear meshing backlash, overall stiffness, and experimental platform center distance. This revealed the influence mechanism of structural parameters on the performance parameters of the end-meshing harmonic reducer. The experimental platform is adjustable, employs a series layout, and all experimental equipment is interchangeable. Sensors of the required type can be installed or replaced at any intermediate stage. Different types of motors, reducers, and brakes can be adjusted to meet specific coaxiality and center distance requirements, and possess sufficient overall stiffness.

[0046] This invention replaces the flexible gear in a traditional harmonic reducer with a rigid element through an end-meshing configuration, improving load-bearing capacity and overcoming the inherent defects of fatigue failure, achieving live-tooth meshing and power transmission. The experimental platform can perform functions such as angle information collection, torque sensing, variable stiffness and adjustable backlash, and can also adjust center distance and coaxiality. It has advantages such as adjustability, interchangeability, high expandability, functional versatility, high stiffness and economy, and can fully adapt to the complexity and long-term nature of future tasks while reducing operating costs.

Claims

1. A side gap and stiffness adjustable end-meshing harmonic reducer, characterized by, The system includes an input base (18), an input shaft (19), a bearing (20), a bearing housing (21), a shaft end retaining ring (22), a single-wave end face cam (23), a universal ball bearing (24), a sleeve (25), a spring (26), a slide rail (27), a grooved wheel (28), a slider (29), a movable gear (30), a rigid wheel (31), an output base (32), an output shaft (33), a snap ring (34), a washer (35), and a housing (36). The input base (18) and the bearing housing (21) are fixedly connected by bolts. The input shaft (19) is connected to the bearing housing (21) and the input base (18) by the bearing (20), and the connection is completed by a snap ring through the shaft shoulder and the hole of the bearing housing (21). Axial positioning; the single-wave end face cam (23) and the input shaft (19) are connected to the hub by a flat key; the shaft end retaining ring (22) is fixed to the input shaft (19) at the end face by a tapered bolt to complete the axial positioning of the single-wave end face cam (23); the output shaft (33) and the output end base (32) are connected by a bearing and axial positioning is completed by a shaft retaining ring (34); the rigid wheel (31) and the output end base (32) are fixed to the end face by bolts, aligning the protrusion of the output end base (32) with the rigid wheel groove to complete the circumferential positioning of the rigid wheel (31); the grooved wheel (28) and the output shaft (33) are connected to the hub by a flat key, and the slide rail (27) is embedded in the groove of the grooved wheel (28). The shaft end retaining ring (22) is fixed to the output shaft (33) at the end face by a tapered bolt to achieve axial positioning of the grooved wheel (28); the movable tooth (30) and the sleeve (25) are fixedly connected by threads on the sleeve surface, and the universal ball bearing (24) is embedded in the sleeve (25); the slider (29) and the movable tooth (30) are fixedly connected by bolts. The movable tooth (30), the sleeve (25), the universal ball bearing (24), and the slider (29) together form the movable tooth assembly. The universal ball bearing (24) realizes the rolling friction between the movable tooth assembly and the single-wave end face cam. The movable tooth assembly slides by placing the slider (29) in the slide rail (27). Both the slider (29) and the slide rail (27) are made of reduced... The material is made of friction material to reduce friction and noise. The spring (26) is arranged around the live tooth (30) and axially positioned by the end face of the sleeve (25). Therefore, the live tooth assembly is in constant contact with the single-wave end face cam (23) and moves axially with its rotation. The tooth profiles of the live tooth (30) and the rigid wheel (31) are all positive helical surfaces, and the top of the teeth is trimmed to improve the meshing characteristics. The input end base (18), the output end base (32) and the housing (36) are fixed together by long bolts. By changing the number of shims (35), the center distance between the input end base (18), the output end base (32) and the housing (36) is adjusted, thereby changing the meshing overlap of the teeth. The meshing clearance and overall stiffness of the live tooth (30) change accordingly.

2. The side play and stiffness adjustable end engagement harmonic reducer according to claim 1, characterized in that, Because there are many live teeth (30), the number of slots required for the grooved wheel (28) is large. At the same time, interference is likely to occur between adjacent live teeth (30), which will inevitably aggravate the vibration of the movement. Therefore, the live teeth (30) are removed by a tooth-removal method. In order to avoid the phenomenon of insufficient load-bearing capacity due to the reduction of the number of meshing teeth at the same time, three gear teeth are set for each group of live teeth (30).

3. The side play and stiffness adjustable end engagement harmonic reducer of claim 1, wherein, The rigid wheel (31) has 50 teeth, and the theoretical total number of teeth of the live gear (30) is 49. Therefore, the transmission ratio is 50, which is the ratio of the number of teeth of the rigid wheel and the difference between the number of teeth of the rigid wheel (31) and the theoretical total number of teeth of the live gear (30). Since the theoretical total number of teeth of the live gear (30) is slightly less than the number of teeth of the rigid wheel (31), the teeth of the live gear (30) always enter the tooth groove of the next rigid wheel (31) after each cycle of movement. The meshing of teeth and the power transmission function are thus realized.

4. A test bench for end-meshing harmonic reducers with adjustable backlash and stiffness, characterized in that, The components include a cast iron perforated plate worktable (1), an aluminum profile (2), a motor base plate (3), a stepper motor (4), an angle iron (5), an angle bracket (6), a coupling (7), a transmission shaft (8), a flange connecting plate (9), an encoder flange (10), an angle encoder (11), a backlash and stiffness adjustable end-meshing harmonic reducer (12) as described in any one of claims 1-3, a reducer base plate (13), a torque sensor connecting flange (14), a torque sensor (15), a magnetic powder brake (16), and a brake connecting flange (17); wherein the cast iron perforated plate worktable (1) The aluminum profile (2) is fixed to the aluminum profile (2) by bolts and washers. The aluminum profile (2) has a scale, and the specific center distance can be adjusted by aligning the experimental equipment base plate with the scale. The motor base plate (3) and the reducer base plate (13) are fixed to the aluminum profile (2) by T-bolts and nuts. The relative position of the motor base plate (3) and the reducer base plate (13) can be determined by sliding the T-nut in the groove of the aluminum profile (2) and aligning it with the required scale. The stepper motor (4) is fixed to the motor base plate (3) by angle iron (5). The vertical height is determined by the position of the bolt in the long hole of the angle iron (5). To adjust the coaxiality of the system; the flange connecting plate (9), the torque sensor connecting flange (14), and the brake connecting flange (17) are all fixed to the aluminum profile (2) by angle brackets and T-bolts. The relative positions of the flange connecting plate (9), the torque sensor connecting flange (14), and the brake connecting flange (17) can be determined by sliding the T-nut in the groove of the aluminum profile (2) and aligning it with the required scale; the flange connecting plate (9) is fixed to the encoder flange (10) by bolts; the angle encoder (11) consists of a fixed end and a movable end, and its fixed end is connected to the encoder flange (10) The system is fixed by bolts; the adjustable backlash and stiffness end meshing harmonic reducer (12) and reducer base plate (13) are fixed by angle iron (5), and the vertical height is determined by the position of the bolt in the hole of angle iron (5) to adjust the coaxiality of the system; the brake connecting flange (17) and aluminum profile (2) are fixed by angle bracket (6), and fixed by bolts to magnetic powder brake (16); the drive shaft (8) is fixed by coupling (7) to stepper motor (4), adjustable backlash and stiffness end meshing harmonic reducer (12), magnetic powder brake (16) and torque sensor (15) to transmit power.

5. The play and stiffness adjustable, end-engaging harmonic reducer test bed according to claim 4, characterized in that, The stepper motor (4), magnetic powder brake (16), angle encoder (11) and torque sensor (15) are all powered by a battery. The battery is placed on the upper part of the cast iron perforated plate and can be charged through the interface current. The speed and torque characteristics of the stepper motor (4) are adjusted by a controller and a pulse generator. The controller and pulse generator are placed on the upper part of the cast iron perforated plate.

6. Use of a test bench for end-meshing harmonic reducers with adjustable backlash and stiffness, characterized in that, The battery provides power to the stepper motor, magnetic powder brake, angle encoder, torque sensor, and their control and debugging components. The stepper motor controller adjusts the stepper motor's microstepping and torque characteristics. A pulse generator sends pulse signals to the stepper motor and adjusts the duty cycle, allowing the stepper motor to input power at a specific speed. This power is transmitted through the drive shaft and coupling to the end-meshing harmonic reducer. The end-meshing harmonic reducer then amplifies the torque through staggered meshing and transmits the power to the torque sensor. Finally, the magnetic powder brake provides a variable output load. Absolute angle encoders are installed on both the input and output drive shafts, allowing continuous multi-turn measurements of the real-time angle information at both ends. The signals are transmitted to the host computer to generate angle curves. Data processing yields angular velocity and angular acceleration curves, serving as the basis for dynamic performance analysis of the end-meshing harmonic reducer. The encoder interface connects to the debugger to determine and correct the initial state. The torque sensor is placed between the output encoder and the magnetic powder brake, allowing real-time measurement of the output torque information and transmission of the signal to the host computer. The magnetic powder brake interface connects to the controller, allowing adjustment of the load torque value to achieve data acquisition under variable operating conditions. Adjusting the number of shims in the end-meshing harmonic reducer allows adjustment of the center distance between the rigid wheel, the live gear assembly, and the single-wave end face cam, thereby adjusting the gear tooth meshing overlap. The live gear meshing backlash and overall stiffness change accordingly. Adjusting the relative positions between the base plate and flange and the aluminum profile changes the center distance of the experimental equipment, which in turn changes the overall stiffness of the experimental platform. Data from multiple sets of structural parameters under various operating conditions are measured and the signals are collected to the host computer. After data processing, the transmission error, vibration characteristics, and torque characteristics of the end-meshing harmonic reducer under variable parameters such as gear meshing backlash, overall stiffness, and experimental platform center distance are obtained. This reveals the influence mechanism of structural parameters on the performance parameters of the end-meshing harmonic reducer.

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