CN101269425A - Round-head gear hob and self-chamfering hob of round-head gear - Google Patents

Abstract

The invention relates to a round head grinding-retention hobbing cutter and a round head grinding-retention self-chamfer hobbing cutter, which are the the round head grinding-retention hobbing cutter and the round head grinding-retention self-chamfer hobbing cutter used for processing a high-speed heavy-duty gear. The structure is as follows: the tooth crest of the round head grinding-retention hobbing cutter is a circular arc; the circular arc is connected with a main cutting edge through a chamfered corner; the design value R of the circular arc is equal to [(Pimn/4 plus (Delta1minus Deltal2) minus-cosine Alpha minus1.4mntg Alpha)] tf (45 DEG plus Alpha/2); wherein, Delta1 is projection amount, Delta2 is grinding-retention amount, (Delta1 minus Delta2) is the difference between the projection amount and the grinding-retention amount, and Alpha is the pressure angle Alpha of a main cutting edge. The round head grinding-retention hobbing cutter and the round head grinding-retention self-chamfer hobbing cutter solve the technical shortcomings that: with the adoption of the common grinding-retention hobbing cutter for processing and producing the high-speed heavy-duty gear, the wheel gear dedendum part transition curve as well as the root straight line are connected with the tooth part involute; after the hobbing cutter is processed, when being abrasively processed through carburize quenching, the root part generates a grinding step and is a straight. The round head grinding-retention hobbing cutter and the round head grinding-retention self-chamfer hobbing cutter has a segment of a circular arc satisfying the requirement of the root part of the high-speed heavy-duty gear for rounding off and avoids the generation of the grinding step.

Description

Round end stays mill hobboing cutter and round end to stay mill from tooth-rounding hob

Technical field

The present invention relates to a kind of machine tools, particularly a kind of round end of processing the high-speed overload gear stays mill hobboing cutter and round end to stay mill from tooth-rounding hob.

Background technology

Before the present invention, as shown in Figure 1 be the common mill hobboing cutter basic tooth profile that stays, the cutter tooth top is a straight line, there is R=0.2-0.3m at the tooth top two ends _nFillet and tangent with main cutting edge, adopt this common mill hobboing cutter processing of staying, making the high-speed overload gear exists gear teeth root easement curve to add root straight line and tooth portion slick and sly connection of involute, and this gear roll processing after during the carburizing and quenching grinding tooth root portion produce the grinding step and tooth root portion is the technological deficiency of a straight line, and never obtain fine solution, as shown in Figure 2, rolling cut backgear involute flank 1, gear compound graduation circle 2, fillet curve 3 (approximate circular arc), the back-geared involute flank 5 of grinding, the monolateral stock removal 4 of gear teeth face, the form of gear tooth after the carburizing and quenching grinding as shown in Figure 3, the grinding step I that grinding produces, this place fractures at this place behind the stand under load easily for stress raiser.Is that a straight line two tooth angle place very little easement curves of radius of curvature are connected with the profile of tooth behind the common hob cutting in tooth portion, the continuous curve nature of such tooth portion produces the grinding step after grinding, and the big specification requirement of high-speed overload gear two 1. tooth root portions do not allow to produce the grinding step after to be a complete smooth curve (easement curve) be connected 2. grindings with flank of tooth involute is slick and sly, overcome above-mentioned defective so must redesign a kind of basic tooth profile of cutter, satisfy the requirement of high-speed overload gear.

Summary of the invention

Purpose of the present invention just is to overcome above-mentioned defective, designs a kind of round end and stays mill hobboing cutter and round end to stay mill from tooth-rounding hob.

Technical scheme of the present invention is:

Round end stays mill hobboing cutter and round end to stay mill from tooth-rounding hob, and its major technique is characterised in that it is circular arc that round end stays mill hobboing cutter tooth top, and circular arc is connected with main cutting edge by transitional edges, the circular arc design load

R＝[(πm _n/4+(δ-Δ)-cosα-1.4m _nt _gα)]t _g(45°+α/2)

Wherein, δ is a projection amount, and Δ is for staying the mill amount, and (δ-Δ) is main cutting edge pressure angle α for projection amount with staying the poor of mill amount, α.

When advantage of the present invention and effect are the R circular arc gear hobbing of this cutter top at the gear root, form easement curve (approximate circular arc) according to the generate process principle, thereby satisfied one section required circular arc of high-speed overload gear root rounding off requirement, meanwhile R has given when design and has stayed the projection amount (δ-Δ) of avoiding producing the effect of grinding step, projection amount exist in cutting the time effect of uprooting in advance, so do not produce the grinding step during grinding, thereby two a big technological deficiency and difficult problems when having solved the high-speed overload gear and making.

Other advantage of the present invention and effect will continue to describe below.

Description of drawings

Fig. 1---the common basic tooth profile schematic diagram that stays the mill hobboing cutter.

Fig. 2---the common form of gear tooth schematic diagram that stays after the gear hobbing of mill hobboing cutter is processed.

Fig. 3---the common form of gear tooth schematic diagram of gear after the carburizing and quenching grinding that stays after the mill hobboing cutter is processed.

Fig. 4---round end of the present invention stays mill hobboing cutter basic tooth profile schematic diagram.

Fig. 5---round end of the present invention stays the form of gear tooth schematic diagram behind the mill hob cutting.

Fig. 6---the form of gear tooth schematic diagram after the carburizing and quenching grinding of the present invention.

Fig. 7---round end of the present invention stays the basic tooth profile schematic diagram of mill from tooth-rounding hob.

Fig. 8---round end of the present invention stays the form of gear tooth schematic diagram of mill from the tooth-rounding hob rolling cut.

The specific embodiment

As shown in Figure 4, R circular arc 6, transitional edges 7, main cutting edge 8, transitional edges pressure angle α 9, main cutting edge pressure angle α 10, stay mill amount Δ 11, projection amount δ 12, its design load is:

R＝[(πm _n/4+(δ-Δ)-cos?α-1.4m _nt _gα)]t _g(45°+α/2)

Give during this R radius distance value design and stayed the grinding projection amount δ 12 that avoids producing the grinding step, the cutter tooth top is a R circular arc 6, link by transitional edges 7 and main cutting edge 8, transitional edges pressure angle 9 α '=α/2, this value is the design load after taking all factors into consideration, it had both guaranteed that transitional edges 7 had certain angle, rear flank during fabrication, do not make the not enough defective of the long caused involute flank length of run of transitional edges again, main cutting edge 8 is the oblique line of pressure angle α 10=α, main play the generated involute flank of tooth and pressure angle of involute equals α, stay mill amount Δ 11 to stay the mill amount for the Tool in Cutting gear, projection amount δ 12 is realized by cutter R radius value for to avoid producing the projection amount that grinding step face is stayed; During circular arc 6 gear hobbings at this cutter top at the gear root, form easement curve (approximate circular arc) according to the generate process principle, make high-speed overload gear root obtain one section required circular arc, meanwhile when the design of circular arc 6, just given allowance poor (δ-Δ) avoiding producing the projection amount δ 12 of grinding step effect and stay mill amount Δ 11, difference that should (δ-Δ) exist in cutting the time effect of uprooting in advance, so can not produce the grinding step during grinding, the defective of having avoided stress to concentrate is as Fig. 5, shown in Figure 6.

As shown in Figure 7,, save labour and cost, stay on the mill hobboing cutter at round end to be provided with, form round end and stay mill, at the distance cutter tooth top (2.2m of place from tooth-rounding hob from chamfering cutting edge 13 for reducing operation _n-2.65m _nIn the scope) be the inclined cutting sword 13 of pressure angle=45 °, pressure angle α " 14=45 °, because the pressure angle of oblique cutting edge is 45 °, thus automatically chamfer machining is carried out in the tooth top both sides of gear during gear hobbing, the rolling cut end, the tooth top chamfering is finished automatically.

Fig. 8 is that round end stays the form of gear tooth of mill from the tooth-rounding hob rolling cut, and shade III place is a gear teeth profile of tooth, and there is (0.2-0.25) m of automatic formation at the tooth top place _nX45 ° chamfering; Shade IV place is a cutter; Cutter be on the basis of Fig. 5 cutter to the further expansion of tool function, it has increased the function to the gear teeth tips automatic chamfering again except that the function with Fig. 5 cutter, very strong practical value is arranged.Fig. 7 only has been to increase the oblique cutting edge of pressure angle=45 ° from the difference of tooth-rounding hob and Fig. 4 cutter, other each one is identical with Fig. 4, and it has increased the chamfering function of tooth top when having behind Fig. 4 cutter rolling cut no grinding step function behind the tooth root rounding off and grinding.

Use round end of the present invention to stay mill hobboing cutter and round end to stay mill can satisfy the manufacturing requirement of high-speed overload gear fully from tooth-rounding hob, high-speed overload gear linear velocity by its manufacturing has reached 148m/sec, rotating speed reaches 5.5 ten thousand commentaries on classics/min, transient speed reaches 6.7 ten thousand commentaries on classics/min, and the rotative power of maximum tooth roller box reaches 5.5 ten thousand kilowatts.

The scope that the present invention asks for protection is not limited only to the description of this specific embodiment.

Claims (2)

1. round end stays mill hobboing cutter and round end to stay mill from tooth-rounding hob, it is characterized in that it is circular arc that round end stays mill hobboing cutter tooth top, and circular arc is connected with main cutting edge by transitional edges, the circular arc design load

R＝[(πm _n/4+(δ-Δ)-cosα-1.4m _nt _gα)]t _g(45°+α/2)

Wherein, δ is a projection amount, and Δ is for staying the mill amount, and (δ-Δ) is main cutting edge pressure angle α for projection amount with staying the poor of mill amount, α.

2. round end according to claim 1 stays mill from tooth-rounding hob, it is characterized in that at distance cutter tooth top 2.2-2.65m _aThe place is provided with pressure angle α " be 45 ° inclined cutting sword.

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