Machining method for flexural gears used in harmonic reducers

Abstract

This invention discloses a method for machining a flexible gear for a harmonic reducer, comprising the following steps: S1, blanking; S2, upsetting and drawing; S3, forging to obtain a prototype; S4, performing a first-stage preheating and a second-stage preheating; S5, quenching treatment; S6, first-stage tempering treatment; S7, rough turning; S8, second-stage tempering treatment; S9, finish turning; S10, machining the gear teeth; S11, surface hardening treatment to obtain the finished flexible gear. This invention rationally improves the steps of steel heat treatment, turning, gear tooth machining, and surface hardening treatment, thereby increasing the strength of the flexible gear itself and improving the machining accuracy of the gear teeth. This ensures that the flexible gear, when used in a harmonic reducer, guarantees high precision and stability for the reducer and extends the service life of the reducer.

Description

Technical Field

[0001] This invention relates to the field of harmonic reducer technology, and in particular to a method for processing a flexible wheel for a harmonic reducer. Background Technology

[0002] Harmonic reducers are precision speed reduction devices widely used in various industrial fields. The flexspline is one of the core components of a harmonic reducer, and its performance (e.g., precision, hardness, stability) directly affects the performance and service life of the reducer. In existing technologies, the performance of the flexspline is often improved by using superior materials, which not only significantly increases costs but also does not yield significant performance improvements. In view of the above technical problems, this invention proposes a processing method for the flexspline of a harmonic reducer to improve its precision and stability. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for processing a flexible wheel for a harmonic reducer, which aims to solve the technical problem that the performance of the flexible wheel in the harmonic reducer needs to be further improved in the prior art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for machining a flexspline for a harmonic reducer includes the following steps: S1, Select 40CrNiMo raw material steel bar and cut it to obtain billet; S2, upsetting and drawing the billet; S3, the billet is forged to obtain a prototype; the prototype includes a cylinder and end plates. S4, heat the prototype to 780~800℃ for a first-stage preheating, the first-stage preheating holding time is T1; then heat to 830~850℃ for a second-stage preheating, the second-stage preheating holding time is T2, and then cool to room temperature; S5, heat to 850~890℃, hold for a period of time, and then quench after T3; S6, undergo a tempering process, heat to 150~600℃, hold at that temperature for a period of time (T4), and then cool to room temperature; S7. Rough turning is performed on the prototype part, including turning the inner circle, turning the outer circle, and turning the end face; to obtain the semi-finished flexible wheel; S8. The semi-finished flexible wheel undergoes a secondary tempering process, heated to 150~600℃, held at that temperature for a period of time (T5), and then cooled to room temperature. S9, the semi-finished flexible wheel is precision machined; S10, machining the teeth of the semi-finished flexible gear; S11, surface hardening treatment, to obtain the finished flexible wheel.

[0005] Furthermore, in the processing method for the flexible wheel of the harmonic reducer, the upsetting process in step S2 is a cross upsetting process.

[0006] Furthermore, in the processing method for the flexible wheel of the harmonic reducer, the heat preservation time T1 of the first stage of preheating in step S4 is 20~30 minutes; the heat preservation time T2 of the second stage of preheating is 2~2.5 hours.

[0007] Furthermore, in the processing method for the flexible wheel of the harmonic reducer, the heat preservation time T3 in step S5 is 1~2 hours, and the quenching method is oil quenching.

[0008] Furthermore, in the processing method for the flexible wheel of the harmonic reducer, the heat preservation time T4 in step S6 is 2-3 hours.

[0009] Furthermore, in the processing method for the flexible wheel used in the harmonic reducer, in step S8, the heat preservation time T5 is 2 hours.

[0010] Furthermore, in the processing method of the flexible wheel for the harmonic reducer, in step S10, the semi-finished flexible wheel is fixed on a mandrel, and the mandrel is provided with a cooperating conical boss and a conical recess. The conical recess is inserted into the cylinder of the semi-finished flexible wheel, and the outer wall of the conical recess is cylindrical.

[0011] Furthermore, in the processing method for the flexure wheel used in the harmonic reducer, the thickness of the finished flexure wheel cylinder is 0.01d~0.02d, and the length of the finished flexure wheel cylinder is 0.5d~0.12d; where d is the diameter of the pitch circle of the flexure wheel.

[0012] Furthermore, in the processing method for the flexible wheel of the harmonic reducer, the surface hardening treatment in step S11 is carburizing treatment.

[0013] Beneficial Effects: This invention provides a processing method for a flexible wheel in a harmonic reducer. Compared with existing technologies, steps S2 and S3, through upsetting and forging, improve the steel's fibrous structure, significantly refine the grains, and produce a prototype free of obvious defects such as cracks, holes, porosity, and fissures, ensuring that the connection between the flexible wheel's cylinder and end plate is less prone to cracking. In step S4, the first and second preheating stages ensure more thorough preheating, which helps eliminate internal stress and reduce carbide precipitation. In step S5, heating to 850-890℃ and holding before quenching helps eliminate internal structural defects in the 40CrNiMo steel and improves its strength and toughness; subsequent quenching treatment allows the 40CrNiMo steel to achieve high strength and hardness. In step S6, the first tempering treatment reduces the material's hardness and brittleness, while improving its toughness and plasticity. In step S8, the second tempering further eliminates residual stress, making the flexible wheel less prone to cracking. Furthermore, by further defining the structure of the gear teeth, the strength and service life of the harmonic reducer can be improved. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the flex wheel clamping of the harmonic reducer provided by the present invention. Detailed Implementation

[0015] This invention provides a method for processing a flexspline for a harmonic reducer. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0016] This invention provides a method for processing a flexspline for a harmonic reducer. The accompanying drawings are for illustrative purposes only and are not to scale with actual products. The drawings only depict structures relevant to the invention; some conventional structures are not specifically shown.

[0017] The method for machining the flexspline for the harmonic reducer includes the following steps: S1, Select 40CrNiMo raw material steel bar and cut it to obtain billet; S2, upsetting and drawing the billet; S3, the billet is forged to obtain a prototype; the prototype includes a cylinder and end plates. S4, heat the prototype to 780~800℃ for a first-stage preheating, the first-stage preheating holding time is T1; then heat to 830~850℃ for a second-stage preheating, the second-stage preheating holding time is T2, and then cool to room temperature; S5, heat to 850~890℃, hold for a period of time, and then quench after T3; S6, undergo a tempering process, heat to 150~600℃, hold at that temperature for a period of time (T4), and then cool to room temperature; S7. Rough turning is performed on the prototype part, including turning the inner circle, turning the outer circle, and turning the end face; to obtain the semi-finished flexible wheel; S8. The semi-finished flexible wheel undergoes a secondary tempering process, heated to 150~600℃, held at that temperature for a period of time (T5), and then cooled to room temperature. S9, the semi-finished flexible wheel is precision machined; S10, machining the teeth of the semi-finished flexible gear; S11, surface hardening treatment, to obtain the finished flexible wheel.

[0018] Preferably, the upsetting process in step S2 is a cross upsetting process.

[0019] Preferably, the heat preservation time T1 for the first stage of preheating in step S4 is 20 to 30 minutes; the heat preservation time T2 for the second stage of preheating is 2 to 2.5 hours.

[0020] Preferably, the holding time T3 in step S5 is 1 to 2 hours, and the quenching method is oil quenching.

[0021] Preferably, the heat preservation time T4 in step S6 is 2 to 3 hours.

[0022] Preferably, in step S8, the heat preservation time T5 is 2 hours.

[0023] like Figure 1 As shown, preferably, in step S10, the semi-finished flexible wheel is fixed on a mandrel 1. The mandrel is provided with a cooperating conical boss 31 and a conical recess 32. The conical recess is inserted into the cylinder of the semi-finished flexible wheel, and the outer wall of the conical recess is cylindrical. Two nuts 2 are also provided on the mandrel for clamping. The conical recess actually acts as an expansion sleeve. In use, the flexible wheel workpiece 9 (including the cylinder 91 and end plate 92) is placed on the conical recess. After tightening the nuts, the conical recess expands slightly, clamping the flexible wheel. After processing, the flexible wheel can be easily removed by loosening the nuts. Figure 1 As shown, in practical applications, each nut 2 is provided with a corresponding washer 209.

[0024] Preferably, the thickness of the finished flexible wheel cylinder is 0.01d to 0.02d, and the length of the finished flexible wheel cylinder is 0.5d to 0.12d; where d is the diameter of the pitch circle of the flexible wheel.

[0025] Preferably, the surface hardening treatment in step S11 is carburizing.

[0026] As can be seen from the above analysis, compared with the existing technology, the present invention makes reasonable improvements to the heat treatment, turning, gear machining and surface hardening treatment of 40CrNiMo steel, which improves the strength of the flexible wheel itself and the machining accuracy of the gear teeth. This enables the flexible wheel to ensure that the harmonic reducer has high precision and stability in actual application, and also improves the service life of the harmonic reducer.

[0027] It is understood that those skilled in the art can make equivalent substitutions or changes to the technical solution and inventive concept of the present invention, and all such changes or substitutions should fall within the protection scope of the present invention.

Claims

1. A method for machining a flexspline for a harmonic reducer, characterized in that, Includes the following steps: S1, Select 40CrNiMo raw material steel bar and cut it to obtain billet; S2, the billet is upset; the upset is a cross upset. S3, the billet is forged to obtain a prototype; the prototype includes a cylinder and end plates. S4. Heat the prototype to 780~800℃ for a first-stage preheating, and hold the preheating temperature for 20~30 minutes; then heat to 830~850℃ for a second-stage preheating, and hold the preheating temperature for 2~2.5 hours; then cool to room temperature. S5, heat to 850~890℃, hold for 1~2 hours and then quench, the quenching method is oil quenching; S6, undergo a tempering process by heating to 150~600℃, holding for 2~3 hours, and then cooling to room temperature; S7. Rough turning is performed on the prototype part, including turning the inner circle, turning the outer circle, and turning the end face; to obtain the semi-finished flexible wheel; S8. The semi-finished flexible wheel undergoes a secondary tempering process, heated to 150~600℃, held for 2 hours, and then cooled to room temperature. S9, the semi-finished flexible wheel is precision machined; S10, Machining gear teeth on the semi-finished flexible wheel; In this step, the semi-finished flexible wheel is fixed on a mandrel, and the mandrel is provided with a cooperating conical boss and a conical recess, which are inserted into the cylinder of the semi-finished flexible wheel, and the outer wall of the conical recess is cylindrical. S11, Surface hardening treatment to obtain the finished flexible wheel; the surface hardening treatment is carburizing treatment. The thickness of the finished flexible wheel cylinder is 0.01d~0.02d, and the length of the finished flexible wheel cylinder is 0.5d; where d is the diameter of the pitch circle of the flexible wheel.

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