Machining process of gear/gear sleeve with large diameter

A processing technology and large-diameter technology, applied in metal material coating technology, manufacturing tools, coatings, etc., can solve problems such as decarburization and large gear distortion, and achieve the effect of eliminating surface decarburization

Inactive Publication Date: 2014-06-18
SUZHOU JIEDERUI PRECISION MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, most gears or gear sleeves are directly quenched by carburizing or secondary heating and quenching after carburizing. Due to the high temperature of carburizing, the gear distortion is relatively large after carburizing and quenching.
And after inspection, the qualified rate of gear distortion is only about 60%, and some surfaces have decarburization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Embodiment 1. A large-diameter disc-shaped spiral bevel gear for a single-stage reducer for a truck, with 36 teeth and a modulus of 13 mm, made of SAE8822H steel. Technical requirements The effective hardening layer depth of carburizing and quenching is 1.778~2.285mm, the surface and core hardness are 57~65HRC and 30~45HRC respectively; the metallographic structure of martensite, retained austenite and carbide is 1~5, the surface Depth of non-martensitic structure ≦0.025mm; Distortion requirements: inner hole roundness error≦0.15mm, outer edge flatness error≦0.10mm, inner edge flatness error≦0.20mm.

[0025] It follows the following process route:

[0026] The first step, forging;

[0027] The second step, isothermal normalizing;

[0028] The third step, machining;

[0029] The fourth step, carburizing;

[0030] The fifth step, press quenching;

[0031] The sixth step, tempering;

[0032] The seventh step, the inner hole of the car;

[0033] The eighth step, gear...

Embodiment 2

[0042] Embodiment 2. The gear sleeve of the synchronizer in the transmission of heavy-duty trucks is made of 20CrH steel, the effective hardening layer depth is 0.7~1.5mm, the surface hardness is ≧59HRC, the carbide is ≦1 grade, and the retained austenite is ≦ 15% (volume fraction), inner hole roundness error≦0.10mm, inner hole taper error≦0.05mm.

[0043] It follows the following process route:

[0044] The first step, forging;

[0045] The second step, isothermal normalizing;

[0046] The third step, machining;

[0047] The fourth step, carburizing;

[0048] The fifth step, press quenching;

[0049] The sixth step, tempering;

[0050] The seventh step, the inner hole of the car;

[0051] The eighth step, gear pairing;

[0052] The ninth step, shot blasting;

[0053] The tenth step, phosphating;

[0054] The eleventh step, storage.

[0055] The fourth step carburizing process is: preheating at 460°C for 3 hours → heating at 900°C for 3.5 hours → carburizing at 930°C...

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Abstract

The invention relates to the field of mechanical manufacturing, and in particular relates to a machining process of a gear/gear sleeve with a large diameter. The machining process comprises the following steps of: step 1, forging; step 2, isothermal normalizing; step 3, machining; step 4, carburizing; step 5, quenching via a pressing machine; step 6, tempering; step 7, lathing of an inner bore; step 8, gear pairing; step 9, shot blasting; step 10, phosphating; and step 11, warehousing. The quenching is carried by using the pressing machine, so that influences of various potential distortion factors existing during the machining and the heat treatment of materials in a production process can be removed or reduced under the action of the pressure. According to the machining process provided by the invention, the distortion of the gear/gear sleeve to be machined is controlled in an acceptability limit; and the problem of surface decarburization is basically eliminated.

Description

technical field [0001] The invention relates to the field of mechanical manufacturing, in particular to a large-diameter gear and tooth sleeve processing technology. Background technique [0002] During the heat treatment of the workpiece, especially during the quenching process, there is a temperature difference due to the inconsistent heating and cooling speed of each part of the cross section, and the non-isochronous nature of the structure transformation, which makes the volume expansion and contraction of each part on the cross section of the workpiece uneven. And the elastic-plastic distortion is inconsistent, which leads to the generation of heat treatment stress. The size, state and distribution of heat treatment stress directly affect the quality of heat treatment. For example, once the higher quenching stress exceeds the yield strength and brittle fracture strength of steel, it will cause distortion and even cracking of the workpiece. The causes of heat treatment...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F17/00C21D1/18C21D9/32C23C8/22
Inventor 姚振红
Owner SUZHOU JIEDERUI PRECISION MACHINERY
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