CN102501035A - Quenching and tempering method in tooth punching process of gear with medium-hard tooth surface - Google Patents

Abstract

The invention discloses a quenching and tempering method in tooth punching process of a gear with a medium-hard tooth surface. The method comprises the following steps of: machining of a gear blank: roughly turning and drilling the gear blank after forging and normalizing treatments; rough turning and heat treatment of a tooth shape: roughly hobbing the gear to form the tooth shape; releasing needed grinding amount according to a tooth thickness; then quenching and tempering at medium and high temperature, wherein the heating process of the quenching is under the protection of a carbon potential atmosphere; and carrying out shot blasting after the heat treatment; finish machining of the tooth shape: firstly, finely machining a tooth shape assembling standard of the gear by semi-finish turning and accurate grinding; and then finely machining the tooth shape of the gear by tooth grinding. The gear manufactured by the method disclosed by the invention has the advantages that the hardness of the tooth surface and the tooth root is improved, the hardness of the quenched and tempered tooth surface ranges from about HB340-370, thereby solving the problem that the medium-hard gear hobbing tool with tooth surface hardness higher than HB320 is difficult to machine. As a process of hobbing before the heat treatment is adopted in the method, the hobbing efficiency is greatly improved and the tool loss is reduced.

Description

The processing method that the tooth punching of a kind of middle hard gear-face gear is modified

Technical field

What the present invention relates to is a kind of gear working method, the processing method that the tooth punching of in particular a kind of middle hard gear-face gear is modified.

Background technology

Because the cutting hardness of hobboing cutter can only be processed the part below the HB320 usually.And the product that the has product of some imports especially, quenching and tempering hardness often reaches HB350 even higher, often is to adopt two kinds of methods to such part: a kind of be with in the quenching and tempering hardness people of hard gear for being reduced to below the HB320; Another kind makes gear into hardened face gear, improves intensity and precision.

These two kinds of methods all have weak point separately, and first method is to be that cost satisfies existing gear hobbing working ability to sacrifice a part of intensity, and the gear teeth face behind the finished product is inhomogeneous to tooth root hardness from tooth top, and this can reduce the service life of gear; Second kind then is that the material of gear has been used low-carbon alloy steel instead, has increased the carburizing and quenching Technology for Heating Processing, has increased very big cost.

Summary of the invention

Goal of the invention: the objective of the invention is to overcome the deficiency of prior art, provide the tooth punching of a kind of middle hard gear-face gear modified processing method, the tooth face hardness of hard gear is inhomogeneous in the solution, and tooth face hardness satisfies the processing of above lathe of HB350 and cutter.

Technical scheme: the present invention realizes through following technical scheme, the present invention includes following steps:

(1) the tooth base is processed: after the tooth base is forged normalized treatment, carry out rough turn and boring;

(2) profile of tooth roughing and heat treatment: thick gear hobbing processes profile of tooth, and transverse tooth thickness is emitted the mill amount that needs, and quenches then and middle high tempering, and the heating process of quenching is protected with carbon potential atmosphere, carries out bead after the heat treatment;

(3) profile of tooth fine finishining: at first the tooth-formation of gear reference for assembling is carried out fine finishining, through roll flute tooth-formation of gear is carried out fine finishining then through half finish turning and correct grinding.

Heat treatment may further comprise the steps in the said step (2):

(1) gear after the roughing is heated to 800～900 ℃ in carbon potential atmosphere, oil quenching;

(2) at 450～550 ℃ gear is carried out temper then.

Beneficial effect: the present invention compares prior art and has the following advantages: gear of the present invention is a common medium-carbon steel; The gear that uses method of the present invention to prepare has improved flank of tooth tooth root hardness; Tooth face hardness after the modifier treatment can reduce middle hard gear-face gear teeth portion spot corrosion situation greatly about HB340～370; Solved the problem that tooth face hardness is higher than the middle hardness gear gear hobbing cutter processing difficulties of HB320; Because the present invention adopts the preceding thick gear hobbing processing of heat, has improved gear hobbing effectiveness greatly, has reduced the cutter loss.

The specific embodiment

Elaborate in the face of embodiments of the invention down, present embodiment provided detailed embodiment and concrete operating process, but protection scope of the present invention is not limited to following embodiment being to implement under the prerequisite with technical scheme of the present invention.

As shown in Figure 1, the middle hard gear-face gear that present embodiment need be processed is 42CrMoA; Modulus is m=14, and the number of teeth is z=65, and addendum coefficient is ha=1, the hand of spiral left, pressure angle α=20 °, helixangle=14 °, tip clearance coefficient C=0.25, overlap arc X=0.153, centre-to-centre spacing a=620mm.

Present embodiment may further comprise the steps:

(1) the tooth base is processed: after the tooth base is forged normalized treatment, carry out rough turn and boring;

Concrete rough turn and boring is as follows:

1) earlier rough turnly goes out each one, then in left datum level mint-mark;

2) the tooth base after rough turn carries out the ultrasonic examination inspection, guarantees not have the tooth base not have obvious defects;

3) on the center circle of no mint-mark face, hole then;

(2) profile of tooth roughing and heat treatment: thick gear hobbing processes profile of tooth, and transverse tooth thickness is emitted the suitable mill amount that needs, and heat-treats then, and heat treatment process comprises quenches and the processing of middle high tempering, and heating process is protected with carbon potential atmosphere, carries out bead after the heat treatment;

Thick agglomeration is drawn together:

1) at first with mint-mark face location, gear is carried out axial compression, the verification outside circle is beated, allowable error 0.05mm;

2) carry out thick gear hobbing then, deburring is carried out chamfering to the parts of tooth at tooth two ends again.

Heat treatment process may further comprise the steps:

1) gear after the roughing is heated to about 860 ℃ oil quenching in carbon potential atmosphere;

2) then the gear tempering 8 after 500 ℃ of left and right sides temperature are to oil quenching by 10 hours;

(3) profile of tooth fine finishining: tooth-formation of gear is carried out fine finishining through half finish turning, correct grinding and roll flute.

Half finish turning detailed process is following:

The car both ends of the surface are put the mill amount and are 0.1～0.2mm respectively, and the mill amount of putting of skiving tip circle is 0.4～0.5mm, and it is 0.4～0.5mm that the car endoporus is put the mill amount; And on datum level marking (that end face that gets off with endoporus one cutter car); Sharp edge is carried out abate.

Behind half finish turning hardness is checked that this moment, gear hardness can reach about HB350, integral hardness is even.

The correct grinding detailed process is following:

Grind both ends of the surface respectively to total thickness, roll flute tip circle and endoporus are to drawing requirement.

Roll flute may further comprise the steps:

1) with left datum end face location, end face fastens, and the verification endoporus is beated, and allowable error is 0.01mm, slightly finish grindes profile of tooth to drawing requirement;

2) by the standard correction of the flank shape, tooth root rounding off, tooth top rounding.

At last, the gear of moulding is carried out magnetic particle testing, demagnetization then, line cutting keyway meets the demands again, removes the burr of each one, and sharp rib abate is got final product.

Claims (2)

1. the modified processing method of middle hard gear-face gear tooth punching is characterized in that, may further comprise the steps:

(1) the tooth base is processed: after the tooth base is forged normalized treatment, carry out rough turn and boring;

(2) profile of tooth roughing and heat treatment: thick gear hobbing processes profile of tooth, and transverse tooth thickness is emitted the mill amount that needs, and quenches then and middle high tempering, and the heating process of quenching is protected with carbon potential atmosphere, carries out bead after the heat treatment;

(3) profile of tooth fine finishining: at first the tooth-formation of gear reference for assembling is carried out fine finishining, through roll flute tooth-formation of gear is carried out fine finishining then through half finish turning and correct grinding.

2. the processing method that a kind of middle hard gear-face gear according to claim 1 tooth punching is modified is characterized in that, heat treatment may further comprise the steps in the said step (2):

(1) gear after the roughing is heated to 800～900 ℃ in carbon potential atmosphere, oil quenching;

(2) at 450～550 ℃ gear is carried out temper then.

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