CN201190777Y - Tooth depth-varying gear - Google Patents

Abstract

The utility model relates to a gear with variable tooth depth, belonging to the mechanical transmission technical field, which comprises gear teeth uniformly distributed along a circumference and involute tooth profiles at two sides of the gear teeth, wherein the relationship between the tooth addendum ha of the basic tooth profile of the gear teeth and the gear modulus is 1.05<=ha<=1.25m. The utility model can modify structure to increase the length of mesh lines by 15% around, improve the contact bearing ability by at least 10%, improve the bending bearing ability by 5-9% and reduce noise, without increasing the material cost, changing tools, changing process and increasing manufacture difficulty of the gear. Therefore, the utility model has substantive features and outburst progress.

Description

Gear wheel with changed tooth height

Technical field

The utility model relates to a kind of gear, and especially a kind of improvement of involute gear belongs to the mechanical transmissioning technology field.

Background technique

Involute gear is most widely used a kind of gear in various gear transmissions.Since the eighties of last century the eighties, the hardened face gear of employing carburizing and quenching roll flute has day by day replaced the soft flank of tooth and the middle hard gear-face gear of normalizing or quenching with Subsequent tempering gear hobbing, becomes the main trend of current gear technique development.

The basic parameter of involute gear has pressure angle, addendum coefficient, tip clearance coefficient, top circle angular coefficient etc.For the unification of cutter, domestic and international standard of all working out the involute gear basic rack tooth profile.For the gear of 20 °, 25 ° pressure angles, its tip clearance coefficient, top circle angular coefficient have variation, but addendum coefficient all equals 1.To the gear that different processing technologys are made, its tip clearance coefficient, top circle angular coefficient also have variation, but addendum coefficient also all equals 1.For a long time, all designing and calculating of gear are all followed this certificate.

Below be example (pressure angle is 25 ° and can analogizes) with the gear of 20 ° of pressure angles.

Fig. 1 is modified or the basic rack tooth profile of the soft flank of tooth of normalized treatment gear hobbing and middle hard gear-face gear.Among Fig. 1, α-pressure angle, α=20 °;

The ha-addendum, ha=han*m;

The m-modulus is a normal module to helical gear;

The han*-addendum coefficient, han*=1;

H '-working depth, h '=2han*m;

The c-bottom clearance, c=c _n* m;

c _n*-and tip clearance coefficient, c _n*=0.25;

The h-whole depth, h=2.25m;

The p-tooth pitch, p=π m;

ρ _f-Fillet radius, ρ _f≈ 0.38m.

Fig. 2 is the basic rack tooth profile of the hardened face gear of carburizing and quenching roll flute.

Among Fig. 2, α-pressure angle, α=20 °;

The ha-addendum, ha=han*m;

The han*-addendum coefficient, han*=1;

Ha0-dedendum of the tooth (comprising bottom clearance), ha0=1.4m;

The c-bottom clearance, c=c _n* m;

c _n*-and tip clearance coefficient, c _n*=0.4;

The h-whole depth, h=2.40m;

The p-tooth pitch, p=π m;

α _F-excessive sword pressure angle;

u _F-the amount of uprooting;

ρ _f-Fillet radius, ρ _f≈ 0.39m.

Addendum coefficient has determined gear tooth supporting plane height, influences transverse contact ratio ε _α, and bearing capacity and noise.

More than the common ground of two kinds of basic rack tooth profiles be: addendum coefficient han*=1, addendum and dedendum of the tooth (not comprising bottom clearance) equate, working depth h '=2han*m, the addendum coefficient of a pair of phase gear equates.

Many times along in the conventional application, therefore people make the transverse contact ratio that can strengthen fail to strengthen owing to ignored some problem long-term, and the bearing capacity that can improve fails to improve, and the noise that can reduce fails to reduce.

By traditional design method, the tolerance of size of top circle is generally by h9～h11 design.When adopting the hardened face gear of carburizing and quenching roll flute owing to there is heat treatment deformation, after the heat treatment, top circle all have rise to some extent big.In order to guarantee design size, after the heat treatment, carry out car or mill processing to the big top circle that rises.And what will machine away is that hardness is one deck hardened layer of HRC58～HRC62, not only wants expensive man-hour, and because of interrupted cutting, can major injury lathe and cutter, simultaneously, after the hardened layer car of tooth top falls, also can produce certain adverse effect to intensity.(referring to top circle processing after the carburizing and quenching gear heat treatment among Fig. 4 and the contrast signal of not processing two kinds of situation tooth top carburized cases variations).

The model utility content

The technical problems to be solved in the utility model is: at the shortcoming of above prior art existence, under the prerequisite that does not change existing process means and processing conditions, propose a kind of gear wheel with changed tooth height, thereby significantly improve engaging gear transverse contact ratio and bearing capacity, reduce running noise.Further can also after heat, not process top circle, save man-hour, improve tooth top intensity.

The claimant recognizes through studying for a long period of time and scrupulous thinking: the problem of following two aspects is by long-standing neglect:

1), the available flank profil length of Gear Processing generation is greater than the active profile length of reality engagement use, do not use when the involute profile that i.e. processing generates has a segment length (concerning gearwheel, this segment length is often very considerable) to use and cause waste (referring to Fig. 3).Among Fig. 3, h _AFThe available flank profil length that-Gear Processing generates; h _AEThe active profile length that the actual engagement of-gear is used.

2) though, the used single circular arc of carburizing and quenching roll flute gear stay the mill hobboing cutter addendum coefficient equal 1, but the available flank profil length that generates behind the roll flute equals the involute profile length that the processing of 1 rack type cutter generates greater than addendum coefficient, can reach addendum coefficient usually and equal the involute that 1.1～1.14 rack type cutter processing generates and can use flank profil length.These length that generate are also never considered to utilize more, the active profile length longer (referring to Fig. 5) that the available flank profil length that makes Gear Processing generate is used than actual engagement.Among Fig. 5, ha0 is the addendum of cutter, and it equals the dedendum of the tooth that comprises bottom clearance of gear, ha0=1.4m, h1=ρ _f(1-sin α) ≈ 0.39m (20 ° of 1-sin)=0.256m, section are partly for staying the mill part, work addendum h3=ha0-ha1=(1.4-.0256) m=1.144m of the maximum rack type cutter that can reach behind the roll flute.

More than the fact of two aspects be objective reality respectively, fail to cause people's emphasis for a long time, especially never the people considered it is organically connected with design of gears simultaneously, by changing design it is used.The claimant is according to for many years practical experience, groped different parameters, the tip diameter of different size gear behind the carburizing and quenching big number range that rises, and also can be used to it by changing design.

In order to solve above technical problem, the claimant takes all factors into consideration and utilizes after above two aspect factors and the heat treatment top circle big factor that rises, and has proposed gear wheel with changed tooth height of the present utility model.This gear has the gear teeth that are uniformly distributed along the circumference, and described gear teeth both sides are involute profile, it is characterized in that: concern 1.05m≤ha≤1.25m between the addendum ha of described gear basic rack tooth profile and the described module.

The dedendum of the tooth of described gear (not comprising bottom clearance) is 1m, the working depth 2.05m of gear basic rack tooth profile～2.25m, and promptly the addendum of same gear and dedendum of the tooth are unequal.And the addendum of the large and small gear in a pair of gear that is meshed is unequal generally speaking.The utility model further improves: the tolerance of size design of the top circle of described gear is not h9～h11.The size of top circle has been considered the big factor that rises after the heat, for not needing strict dynamically balanced a large amount of industrial gears, does not process after the size heat of top circle.

Like this, by changing the addendum (addendum that adds gearwheel generally speaking) of gear, two-part involute profile that the above-mentioned script of mentioning is not used can be used, do not change dedendum of the tooth to reach, do not need to design the purpose of the noise of the bearing capacity of transverse contact ratio that special tool just realizes strengthening, raising and reduction, reach the purpose of not processing top circle after the heat by tolerance of size and the manufacturing size before the regulation heat that changes top circle simultaneously.

Particularly, application of the present utility model is mainly following three aspects:

1) to widely used carburizing and quenching roll flute gear, adopt still that addendum coefficient equals 1, the tooth top tip clearance coefficient approximates 0.4 the single circular arc of standard and stays under the prerequisite of mill hobboing cutter, can be increased to 1.05m～1.25m scope to the addendum of gear.The most frequently used generally speaking scope is the addendum 1.15m～1.2m of small gear, and individual cases also allow to be increased to 1.25m; The addendum 1.1m of gearwheel～1.15m, individual cases also allow to be increased to 1.20m.The transverse contact ratio of increasing, the bearing capacity of raising and the anti noise of reduction can be obviously played in this change.Usually transverse contact ratio can improve 13%～18%, and the bearing capacity of contact fatigue strength can improve more than 10%, and the bearing capacity of flexural strength can improve 5%～9%.

2) to modified or normalizing gear hobbing gear, still under the prerequisite that adopt that addendum coefficient equals 1, the tooth top tip clearance coefficient equals 0.25 standard hob, can be increased to 1.05m～1.10m to the addendum of gear, the most frequently used generally speaking is the addendum that strengthens small gear, also can strengthen the addendum of gearwheel sometimes simultaneously.Usually transverse contact ratio improves more than 5%, and bearing capacity also can increase.

3) to widely used carburizing and quenching roll flute gear, the tolerance of size of top circle is designed to js12～js13 by different range, the manufacturing size of heat treatment nipper base top circle is added IT9 or subtracts IT9 by the lower deviation that different range is defined as the top circle size, though can reach after the heat treatment top circle have rise to some extent big, but diameter remains in the dimensional tolerance range of drawing design, does not need row processing again.

On basis of the present utility model, as required, can further consider problems such as adjustment such as modification coefficient, parameter optimization, intensity calculating, correction of the flank shape design.

In a word; the utility model is increasing the gear material cost hardly, is not changing cutter, is not changing technology, is not strengthening basically under the prerequisite of manufacture difficulty; with the architecture advances that has scientific basis; can realize improving the length of line of action about 15%; the contact bearing capacity more than 10% that improves; 5%～9% the crooked bearing capacity that improves also reduces the remarkable result of noise, and realizes that not processing top circle after the heat treatment saves man-hour, protection lathe and strengthen tooth top intensity purpose to reach.

Description of drawings

Below in conjunction with accompanying drawing the utility model is further described.

Fig. 1 is modified or the soft flank of tooth of normalized treatment (how with gear hobbing or Gear Shaping) and the basic rack tooth profile schematic representation of middle hard gear-face gear.

Fig. 2 is the basic rack tooth profile schematic representation of the hardened face gear of carburizing and quenching roll flute.

Fig. 3 is existing gear engagement starting point E and involute starting point F position view.Among the figure, h _AFBe the useful flank profil height that processing generates, h _AEBe the actual active profile height of using of engagement.

Fig. 4 is top circle processing after the carburizing and quenching gear heat treatment and the contrast schematic representation that does not add tooth top carburized case variation in man-hour.A) being that carburized case distributes after the carburizing and quenching gear heat treatment wherein, b) be the carburized case situation of processing after the carburizing and quenching gear heat treatment behind the top circle.

The flank profil schematic representation that stays roll flute stripe shape cutter that Fig. 5 has the amount of uprooting for existing single circular arc.

Among Fig. 5: α-pressure angle, α=20 °;

α _F-excessive sword pressure angle;

The ha0-cutter teeth is risen (comprising bottom clearance), ha0=1.4m;

u _F-the amount of uprooting (comprise and stay mill amount and reduction in tooth thickness);

ρ _f-Fillet radius, ρ _f≈ 0.39m;

H1-Fillet and 20 ° of pressure angle tangent line point of contact height;

The apex height of h2-transitional edges;

The work addendum of the maximum rack type cutter that can reach behind the h3-roll flute.

When being derivation gear and gear engagement, calculates Fig. 6 the reference drawing of length of line of action and starting point of meshing circular diameter formula.

Fig. 7 calculates the reference drawing of length of line of action and starting point of meshing circular diameter formula when being derivation gear and tooth bar engagement.

Embodiment

1) (referring to Fig. 6) when design relevant calculation formula (comprising from the derivation formula) gear used of gear wheel with changed tooth height and gear engagement, among Fig. 6:

O ₁, O ₂-small gear, the center of gearwheel;

A '-centre distance;

r _A1, r _A2,-small gear, the Outside radius of gearwheel;

r _B1, r _B2,-small gear, the Base radius of gearwheel;

r ₁, r ₂,-small gear, the reference radius of gearwheel;

α _t'-working pressure angle;

E ₂, E ₁-small gear, the starting point of meshing during the gearwheel engagement;

E ₁E ₂-small gear, the length of line of action during the gearwheel engagement;

O ₁E ₂, O ₂E ₁-small gear, garden, the starting point of meshing radius during the gearwheel engagement.

$E_1{E}_2=\sqrt{{r_{a1}}^2-{r_{b1}}^2}+\sqrt{{r_{a2}}^2-{r_{b2}}^2}-a^{\&prime;}\sin {{\mathrm{\&alpha;}}_t}^{\&prime;}$

$O_2{E}_1=\sqrt{{(a^{\&prime;}\sin {{\mathrm{\&alpha;}}_t}^{\&prime;}-\sqrt{{r_{a1}}^2-{r_{b1}}^2})}^2+{r_{b2}}^2}$

$O_1{E}_2=\sqrt{{(a^{\&prime;}\sin {{\mathrm{\&alpha;}}_t}^{\&prime;}-\sqrt{{r_{a2}}^2-{r_{b2}}^2})}^2+{r_{b1}}^2}$

Small gear and gearwheel mesh practical involute height h _E1=r _A1-O ₁E ₂

The practical involute height of gearwheel and pinion h _E2=r _A2-O ₂E ₁

During the engagement of gear and tooth bar (referring to Fig. 7), Fig. 7 omitted with derive irrelevant

The flank profil of cutter tooth top bottom clearance part, among Fig. 7:

O ₁-with the center of tooth bar engaging gear;

(h _An ^*-x) the tooth bar reference line moves the working depth of the cutter tooth top after the xm distance after the m-displacement;

r _A1-with the Outside radius of tooth bar engaging gear;

r _B1-with the Base radius of tooth bar engaging gear;

r ₁-with the reference radius of tooth bar engaging gear;

r _F1-with the root radius of tooth bar engaging gear;

α _t-working pressure angle;

F ₂The starting point of meshing during engagement of-wheel and rack;

F ₁F ₂Length of line of action during the engagement of-wheel and rack;

O ₁F ₂Garden, the starting point of meshing radius during engagement of-wheel and rack, i.e. the available flank profil starting point circle radius that processing generates.

$F_1{F}_2=\sqrt{{r_{a1}}^2-{r_{b1}}^2}-r_{b1}\tan {\mathrm{\&alpha;}}_t+\frac{({h_{\mathrm{an}}}^{*}-x)m}{\sin {\mathrm{\&alpha;}}_t}$

$O_1{F}_2=\sqrt{{(r_{b1}\tan {\mathrm{\&alpha;}}_t-\frac{({h_{\mathrm{an}}}^{*}-x)m}{\sin {\mathrm{\&alpha;}}_t})}^2+{r_{b1}}^2}$

The available involute height h that gear generates _F1=r _A1-O ₁F ₂

2) determining step

(1) gear parameter of calculating primary standard size.Length of line of action when calculating the wheel and rack engagement and height, length of line of action when gear and gear engagement and height.

(2) determine that tentatively adding of large and small addendum circle diameter of gear is a large amount of.Calculate 2 kinds of length of line of actions and height.

(3) carburizing and quenching gear is determined the processing dimension of top circle tolerance of size and heat treatment nipper base top circle.

(4) do addendum thickness, slip ratio, transverse contact ratio, bottom clearance, calculate with other gear presence of interference etc. and to check.As satisfying, can determine the final size of large and small addendum circle diameter of gear.

3) processing dimension of the top circle tolerance of size of carburizing and quenching gear and heat treatment nipper base top circle determines

During the top circle tolerance of size of part: da on the drawing≤630mm, press js12;

During da＞630mm, press js13.

The processing dimension of the top circle of the tooth base before the carburizing and quenching:

During da≤250mm, the upper deviation adds IT9 by the lower deviation of js12, and lower deviation is pressed the lower deviation of js12;

During 250mm＜da≤630mm, the upper deviation is pressed the lower deviation of js12, and lower deviation subtracts IT9 by the lower deviation of js12;

During da＞630mm, the upper deviation is pressed the lower deviation of js13, and lower deviation subtracts IT9 by the lower deviation of js13;

Press above size and tolerance design and processing, can guarantee under the heat-treat condition of normal control, rise to some extent greatly though heat back top circle has, diameter remains in the dimensional tolerance range of drawing design, does not need row processing again.

4) the relevant check:

(1) guaranteed h because of becoming in the tooth depth design _F＞h _ESo, there is not the meshing interference problem, do not need to do the meshing interference checking computations.

(2) past to the requirement of addendum thickness Sa is: normalizing or modified gear Sa＞0.25m, carburizing and quenching gear Sa＞0.4m.This limits value facts have proved it is too conservative, particularly can be much smaller than above-mentioned value to heat treatment and the stable gear of machining accuracy.Artificer's experience is desirable: normalizing or modified gear Sa＞0.2m, the desirable 0.15m of special circumstances; Carburizing and quenching gear Sa＞0.28m, the desirable 0.25m of special circumstances.

(3) bottom clearance will guarantee that tooth top and teeth groove are in service and not brush up against enough oil storage space mutually, and general 0.2m is enough, the desirable 0.15m of special circumstances.

(4) slip ratio can reduce by selecting rational modification coefficient, generally is controlled in 2, preferably less than 1.5.

(5) during particular design such as other check of needs, can be undertaken by general design of gears computational methods.

Embodiment one

Present embodiment is a pair of carburizing and quenching roll flute gear, and parameter is: modulus m=5mm, number of teeth z1=29, z2=89, centre distance a '=325mm, helixangle=22.5 °, addendum coefficient han ^*=1, tip clearance coefficient C _n ^*=0.4, the modification coefficient x1=0.572 of small gear, the modification coefficient x2=0.6289 of gearwheel, facewidth b=125mm, being designed to gear wheel with changed tooth height can be according to the following steps:

(1) gear parameter and the relevant numerical value of calculating primary standard size.Try to achieve:

The standard pitch diameter d1=156.947mm of little, gearwheel, d2=481.665mm;

The tip diameter da1=172.046mm of little, gearwheel, da2=497.333mm;

The root diameter df1=148.667mm of little, gearwheel, df2=473.954mm;

Small gear is the available involute height h that the processing of 1 rack type cutter generates by addendum coefficient _F1=9.496mm=1.899m;

Small gear and gearwheel mesh practical involute height h _E1=9.182mm=1.837m;

Gearwheel is pressed the available involute height h of the rack type cutter processing generation of addendum coefficient 1 _F2=9.643mm=1.929m;

The practical involute height of gearwheel and pinion h _E2=8.553mm=1.711m;

Small gear, the length of line of action E during the gearwheel engagement ₁E ₂=21.536mm;

Transverse contact ratio ε _α=1.361.

(2) determine that tentatively adding of large and small addendum circle diameter of gear is a large amount of, calculate relevant numerical value.Rise 1.2m by pinion gear teeth, gearwheel addendum 1.1m, try to achieve:

The tip diameter da1=174.046mm of little, gearwheel, da2=498.333mm;

Small gear is the available involute height h of the rack type cutter processing generation of 1.1 (leaving certain surplus) by the cutter addendum coefficient _F1=10.894mm=2.179m;

Small gear and gearwheel mesh practical involute height h _E1=10.533mm=2.107m;

Gearwheel is the available involute height h that the processing of 1.1 rack type cutter generates by the cutter addendum coefficient _F2=10.615mm=2.123m;

The practical involute height of gearwheel and pinion h _E2=9.717mm=1.943m.

Small gear, the length of line of action E during the gearwheel engagement ₁E ₂=24.548mm.

(3) determine the processing dimension of top circle tolerance of size and heat treatment nipper base top circle.

The tip diameter size of small gear and tolerance da1=174.046j s12 (± 0.2) mm;

The tip diameter size of gearwheel and tolerance da2=498.333j s12 (± 0.315) mm.

The processing dimension of heat treatment nipper base top circle:

The upper deviation of the processing dimension of small gear heat treatment nipper base top circle :-0.2+IT9=-0.2+0.1=-0.1mm; Lower deviation :-0.2mm.

The upper deviation of the processing dimension of gearwheel heat treatment nipper base top circle :-0.315mm; Lower deviation :-0.315-IT9=-0.315-0.155=-0.47mm.

(4) addendum thickness of gear wheel with changed tooth height, slip ratio, transverse contact ratio, bottom clearance, calculate with other gear presence of interference etc. and to check

Thick Sa1=2.214mm=0.4428m＞the 0.25m of tooth top little, gearwheel;

Sa2＝3.564mm＝0.7128m＞0.25m；

The slip ratio ξ 1=0.557 of little, gearwheel, ξ 2=0.721 is normal.

Transverse contact ratio ε _α=1.552, improve 14% than former 1.361;

Small gear, the length of line of action during the gearwheel engagement is brought up to 24.548mm by 21.536mm, raising rate 14%;

The tooth top crack Δ 1=1.5mm＞0.2m of little, gearwheel, Δ 2=1.0mm 〉=0.2m; Maximum rising in a large number less than the limit upper deviation adjusted by limit upper deviation value after the tip diameter heat, and Δ 1 reduces 0.315/2=0.16mm, and Δ 2 reduces 0.2/2=0.1mm, can not cause interference.There is not interference through checking computations and other gear.

Calculate through intensity, this becomes tooth depth design back contact strength safety coefficient to gear and brings up to 1.060 by original 1.004, and the contact strength bearing capacity improves 11.4%; The flexural strength safety coefficient of small gear brings up to 1.574 by original 1.497, and the flexural strength bearing capacity improves 5.1%, and the flexural strength safety coefficient of gearwheel brings up to 1.510 by original 1.409, and the flexural strength bearing capacity improves 7.1%.

Small gear original weight 84.5kg becomes tooth depth design back weight and increases 0.54kg, increases by 0.63%; Gearwheel original weight 129kg; become tooth depth design back weight and increase 0.77kg; increase by 0.6%; obtain and improve 14% transverse contact ratio; the contact strength bearing capacity improves 11.4%; the flexural strength bearing capacity improves 5.1%～7.1% remarkable benefit, and has realized not processing top circle after the heat, reaches the effect of saving man-hour, protection lathe and strengthening tooth top intensity.

Embodiment two

Present embodiment is a pair of modified gear hobbing gear, and parameter is: modulus m=9mm, number of teeth z1=18, z2=70, centre distance a '=415mm, helixangle=10 °, addendum coefficient han ^*=1, tip clearance coefficient C _n ^*=0.25, the modification coefficient x1=0.722 of small gear, the modification coefficient x2=0.8627 of gearwheel, facewidth b=190mm, being designed to gear wheel with changed tooth height can be according to the following steps:

(1) gear parameter and the relevant numerical value of calculating primary standard size.Try to achieve:

The standard pitch diameter d1=164.499mm of little, gearwheel, d2=639.719mm;

The tip diameter da1=192.754mm of little, gearwheel, da2=670.505mm;

The root diameter df1=154.995mm of little, gearwheel, df2=632.747mm;

Small gear is the available involute height h that the processing of 1 rack type cutter generates by addendum coefficient _F1=16.342mm=1.816m;

Small gear and gearwheel mesh practical involute height h _E1=15.726mm=1.747m;

Gearwheel is the available involute height h that the processing of 1 rack type cutter generates by addendum coefficient _F2=16.612mm=1.846m;

The practical involute height of gearwheel and pinion h _E2=13.821mm=1.536m;

Small gear, the length of line of action E during the gearwheel engagement ₁E ₂=34.256mm;

Transverse contact ratio ε _α=1.272.

(2) determine that tentatively adding of large and small addendum circle diameter of gear is a large amount of, calculate relevant numerical value.Rise 1.1m by pinion gear teeth, gearwheel addendum 1.05m, try to achieve:

The tip diameter da1=194.554mm of little, gearwheel, da2=671.405mm;

Small gear is the available involute height h that the processing of 1 rack type cutter generates by the cutter addendum coefficient _F1=17.242mm=1.916m;

Small gear and gearwheel mesh practical involute height h _E1=16.913mm=1.879m;

Gearwheel is the available involute height h that the processing of 1 rack type cutter generates by the cutter addendum coefficient _F2=17.062mm=1.896m;

The practical involute height of gearwheel and pinion h _E2=14.802mm=1.645m.

Small gear, the length of line of action E during the gearwheel engagement ₁E ₂=36.751mm.

(3) addendum thickness of gear wheel with changed tooth height, slip ratio, transverse contact ratio, bottom clearance, calculate with other gear presence of interference etc. and to check

Thick Sa1=3.609mm=0.401m＞the 0.20m of tooth top little, gearwheel;

Sa2＝6.756mm＝0.75m＞0.20m；

The slip ratio ξ 1=0.721 of little, gearwheel, ξ 2=1.024 is normal.

Transverse contact ratio ε _α=1.365, than former 1.272 raisings 7.3%,

Small gear, the length of line of action during the gearwheel engagement is brought up to 36.751mm by 34.256mm, raising rate 7.3%;

The tooth top crack Δ 1=1.8mm＞0.15m of little, gearwheel, Δ 2=1.35mm 〉=0.15m; There is not interference through checking computations and other gear.

This becomes tooth depth design back contact ratio to gear obvious increasing, and meshing quality improves, and intensity strengthens to some extent.

In a word, the utility model is studied by long-term practice, according to rigorous theory analysis, has proposed the gear structure of standard that breaks traditions, and has derived concrete design method, thereby made it to have practicability, and is practical by this structure of checking proof.The utility model is increasing the gear material cost hardly, is not changing cutter, is not changing technology, is not strengthening basically under the prerequisite of manufacture difficulty; with the architecture advances that has scientific basis; can realize improving the length of line of action about 15%; the contact bearing capacity more than 10% that improves; 5%～9% the crooked bearing capacity that improves also reduces the remarkable result of noise, and realizes that not processing top circle after the heat treatment saves man-hour, protection lathe and strengthen tooth top intensity purpose to reach.Therefore have significant substantive distinguishing features and outstanding progress.

Claims (6)

1. a gear wheel with changed tooth height has the gear teeth that are uniformly distributed along the circumference, and described gear teeth both sides are involute profile, it is characterized in that: concern 1.05m≤ha≤1.25m between the modulus m of the addendum ha of described gear teeth basic rack tooth profile and described gear.

2. according to the described gear wheel with changed tooth height of claim 1, it is characterized in that: the dedendum of the tooth of described gear basic rack tooth profile is 1m, and the working depth of described gear basic rack tooth profile is 2.05m～2.25m.

3. according to claim 1 or 2 described gear wheel with changed tooth height, it is characterized in that: described gear is the carburizing and quenching roll flute gear of pair of meshing, pressure angle is 20 °, wherein concern 1.05m≤ha≤1.25m between the modulus m of the addendum ha of the gear teeth basic rack tooth profile of small gear and described gear, concern 1.05m≤ha≤1.20m between the addendum ha of the gear teeth basic rack tooth profile of gearwheel and the modulus m of described gear.

4. according to claim 1 or 2 described gear wheel with changed tooth height, it is characterized in that: described gear is the carburizing and quenching roll flute gear of pair of meshing, pressure angle is 25 °, wherein concern 1.05m≤ha≤1.15m between the modulus m of the addendum ha of the gear teeth basic rack tooth profile of small gear and described gear, concern 1.05m≤ha≤1.10m between the addendum ha of the gear teeth basic rack tooth profile of gearwheel and the modulus m of described gear.

5. according to claim 1 or 2 described gear wheel with changed tooth height, it is characterized in that: described gear is the modified or normalized treatment gear of pair of meshing, concerns 1.05m≤ha≤1.1m between the addendum ha of the gear teeth basic rack tooth profile of described large and small gear and the modulus m of described gear.

6. according to the described gear wheel with changed tooth height of claim 3, it is characterized in that: the tolerance of size of described wheel tooth tip circle is js12～js13.

Images