CN102042382B - Gear and method for forming tooth profile of gear - Google Patents

Abstract

The invention provides a gear (30) and a method for forming a tooth profile (40) of the gear (30). In the method, a cubic curve (21) is used to revise a basic rack (15); the cubic curve (21) is tangent to a basic tooth shape (16) of the basic rack (15) in the midpoint of the root (19) of the basic tooth shape (16), the midpoint of the side edge (17) of the basic tooth shape (16) and the midpoint of a crown part (18) of the basic tooth shape (16); the cubic curve (21) forms a revised basic tooth shape (22); the revised basic tooth shape (22) is copied to obtain a revised rack; and the tooth profile (40) of the gear (30) is formed by using the revised rack.

Description

Gear and the method that forms the flank profil of this gear

Technical field

The present invention relates to a kind of gear, relating in particular to the gear Line of contact is the gear of a level and smooth continous curve; The present invention relates to a kind of method that forms the flank profil of this gear in addition, relates in particular to a kind of profile of tooth of utilizing cubic curve correction basic rack, and utilizes the method for the flank profil of revising tooth bar generate (generate, creation) gear.

Background technique

As shown in Figure 1, known rotary gear pump 1 comprises a pump housing 2 and is positioned at driving gear 3 and the driven gear 4 of the pump housing 2 inside.If driving gear 3 rotates towards a certain direction, drive the driven gear 4 that is meshed with driving gear 3 and rotate in the opposite direction, so the fluid that desire can be carried transmits along the space between the wheel tooth portion, and discharges from output terminal 5.

In the gear, the flank profil of tooth portion can utilize tooth bar to come generate.Fig. 2 shows in the rotary gear pump 1, two intermeshing involute gears 6.The flank profil of involute gear 6 comprises an involute 8, root circle interior angle 9 and bizet circle exterior angle 10.

When two involute gears 6 were meshing with each other interlock, the point of contact 7 between two gears can connect into a Line of contact 11.As shown in Figure 2, the Line of contact 11 that involute gear 6 produces is a rough continous curve, and it comprises two straight sectioies and two camber line parts.This straight section is by in two involute gears 6, tooth portion involute 8 parts contact with each other produce, institute was produced when this camber line part then was meshing with each other by the round exterior angle 10 of the bizet of two involute gears 6 and root circle interior angle 9, the tangent line of these Line of contact 11 straight sectioies and camber line part connecting place is discontinuous, therefore can't form level and smooth continous curve." unsmooth " of above-mentioned Line of contact refers to a subdifferential of inter_curve, and just the tangent line of inter_curve is discontinuous.

To a rotary gear pump 1 of carrying fluid, when the discontinuous Line of contact 11 of tangent line can cause pumping, the unsettled pressure of output terminal 5 output devices fluctuation, and the noise when increasing by 6 runnings of two involute gears.In addition, also can't provide accurate, a stable and quantitative output, so industry high-accuracy, high-quality for needs, high stability output, for example the medical application pump influences more so.

On the other hand, most rotary gear pumps especially almost do not have constrictive liquid for delivery of fluid.Engagement figure when Fig. 3 shows Fig. 2 two gears engagement rotation.When if two gears are about to mesh, the crown 12 and 13 on the tooth root that lay respectively at two gears seal 14 if form, produce the contact of two single-points in some moment during i.e. two involute gears, 6 engagements, there is containing space between 2 contacts, the liquid that cause sealing in 14 can't be got rid of, and then two gear interlocks is in a flash following, and the liquid that is positioned at sealing 14 can not had a compressibility because of it, and push the gear of former driving fit fully and damage mechanical structure, also can cause the noise of certain degree in addition.

Summary of the invention

The object of the present invention is to provide a kind of method of flank profil of formative gear; By the gear of said method formation flank profil, the Line of contact when it is meshing with each other is a level and smooth continous curve, the noise in the time of therefore stable fluid supply can being provided and reducing running.

Another object of the present invention is to provide a kind of method of flank profil of formative gear; By the gear of said method formation flank profil, its Shi Buhui that is meshing with each other produces sealing, therefore can not cause fluid extruding gear structure and damage mechanical tissue.

For reaching above-mentioned purpose, the method for the flank profil of formative gear provided by the invention, its step comprises: the module according to desiring Generating gear, obtain a basic rack, a basic profile of tooth of this basic rack comprises a side, a bizet and a root; Utilize the basic profile of tooth of this basic rack of cubic curve correction, revise basic profile of tooth and obtain one, wherein this cubic curve and this basic profile of tooth are tangential on three point of contacts of this root mid point, this side mid point and this bizet mid point; The coefficient of this cubic curve can be obtained by these point of contacts, and can a pressure angle, a full-depth tooth is dark and a facewidth is that parameter is represented; Copy the basic profile of tooth of above-mentioned correction and get a correction tooth bar, utilize the flank profil of this correction tooth bar generate one gear.

The present invention provides a kind of gear in addition, and the flank profil of this gear is by above-mentioned correction tooth bar institute generate.The Line of contact of the gear train that the present invention produces is a level and smooth continous curve, and the noise in the time of therefore can significantly reducing the gear running also obtains stable and several pulsation-free outputs.

Description of drawings

Embodiments of the present invention are described in conjunction with graphic:

Fig. 1 is the schematic representation of known rotary gear pump;

Fig. 2 is in the known rotary gear pump, two involute tooth wheels mesh schematic representations;

Engagement figure when Fig. 3 meshes for the known gears group;

Fig. 4 is the method flow diagram of formative gear of the present invention;

The employed basic rack of Fig. 5 step a of the present invention;

Fig. 6 is for utilizing a cubic curve, revises the basic profile of tooth of Fig. 5 and produces one and revise basic profile of tooth;

Fig. 7 shows gear-profile of the present invention, and shows the tolerance schematic representation of this flank profil;

When Fig. 8 is meshing with each other for gear train of the present invention, the schematic representation of the level and smooth Continuous Contact line of tool; And

Packingless schematic representation when Fig. 9-1 turns round for the present invention's one gear train to Fig. 9-4.

Embodiment

Following example or explanation only are used for describing, explaining marrow of the present invention, but not desire restriction the present invention.Relevant detailed description of the present invention and technology contents now just cooperate graphic being described as follows:

See also shown in the flow chart of Fig. 4, the invention provides a kind of method of flank profil of formative gear, its step comprises:

A. according to the module of desiring Generating gear, obtain a basic rack;

B. utilize the basic profile of tooth of basic rack among the cubic curve correction step a, revise basic profile of tooth and obtain one;

C. copy the basic profile of tooth of correction of above-mentioned steps b and get a correction tooth bar, utilize the flank profil of this correction tooth bar generate one gear.

Below do at length to explain orally with regard to each step:

Among Fig. 4, step a obtains a basic rack according to the module m that desires generate.Module m is by number of teeth n, pitch diameter P _dAnd helixangle _pDefine, as shown in the formula (1):

$m=\frac{P_d\cos {\mathrm{\β}}_p}{n}---\left(1\right)$

According to module, can obtain a basic rack that is used for the Generating gear flank profil, as shown in Figure 5, it shows that a basic rack 15 has a plurality of basic profiles of tooth 16, these basic profiles of tooth 16 comprise a side 17, a bizet 18 and a root 19.

Fig. 6 is among the above-mentioned steps b, utilizes the schematic representation of cubic curve correction basic rack.The shown dotted line of Fig. 6 is among the step a, the basic profile of tooth 16 of basic rack 15.Step b utilizes a cubic curve 21 to revise this basic profile of tooth 16 and obtain the basic profile of tooth 22 of a correction.At first set up a right angled coordinates (X _r, Y _r) to describe this cubic curve 21, the true origin O of right angled coordinates _r, be positioned at the center of facewidth Sw on the nodel line 20, and make nodel line 20 proper and coordinate X _rThe axle conllinear.The tooth depth of this basic rack 15 is h (equaling to desire the dark h of full-depth tooth of Generating gear), and pressure angle then is α.

Revise basic profile of tooth 22 and can utilize cubic curve 21 to describe, show for convenient, cubic curve 21 is divided into X _rAxle upper curve section 21a and X _rAxle lower curve section 21b, definition is shown in (2) and (3) formula respectively:

x _r1＝u

${\mathrm{<figure-callout\; id="1"\; label="y\; r"\; filenames="H2009102066375E00011.png,H2009102066375E00052.png"\; state="\{\{state\}\}">y</figure-callout>}}_r=a_1{u}^3+b_1{u}^2+\frac{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="H2009102066375E00011.png,H2009102066375E00032.png"\; state="\{\{state\}\}">\; <figure-callout\; id="0"\; label="h"\; filenames="H2009102066375E00032.png"\; state="\{\{state\}\}">h</figure-callout>\; </figure-callout>}}{2},0\&le;u\&le;\frac{\mathrm{Sw}}{2}---\left(2\right)$

x _r2＝u+Sw

${\mathrm{<figure-callout\; id="2"\; label="y\; r"\; filenames="H2009102066375E00011.png,H2009102066375E00032.png"\; state="\{\{state\}\}">y</figure-callout>}}_r=a_2{u}^3+b_2{u}^2-\frac{\mathrm{<figure-callout\; id="2"\; label="h"\; filenames="H2009102066375E00011.png,H2009102066375E00032.png"\; state="\{\{state\}\}">h</figure-callout>}}{2},-\frac{\mathrm{<figure-callout\; id="2"\; label="Sw"\; filenames="H2009102066375E00011.png,H2009102066375E00032.png"\; state="\{\{state\}\}">Sw</figure-callout>}}{2}<u\&le;0---\left(3\right)$

The basic profile of tooth 16 of each of this basic rack 15 is tangent at 3 with this cubic curve 21 respectively, comprise that coordinate is (0 in this basic profile of tooth 16, h/2) root 19 mid points, coordinate are that side 17 mid points and the coordinate of (Sw/2,0) is (Sw ,-h/2) bizet 18 mid points.Therefore, by above-mentioned three point of contacts, can solve the coefficient of describing cubic curve 21 formulas (2), formula (3) and be respectively following formula (4), formula (5), can get one by this cubic curve 21 of mirror and revise basic profile of tooth 22.

$a_1=\frac{-4\mathrm{Sw}\cot \mathrm{\&alpha;}+8\mathrm{<figure-callout\; id="3"\; label="h\; Sw"\; filenames="H2009102066375E00011.png"\; state="\{\{state\}\}">h</figure-callout>}}{{\mathrm{Sw}}^{}}$

$b_1=\frac{2\mathrm{Sw}\cot \mathrm{\&alpha;}-6h}{{\mathrm{Sw}}^2}---\left(4\right)$

$a_2=\frac{-4\mathrm{Sw}\cot \mathrm{\&alpha;}+8\mathrm{<figure-callout\; id="3"\; label="h\; Sw"\; filenames="H2009102066375E00011.png"\; state="\{\{state\}\}">h</figure-callout>}}{{\mathrm{Sw}}^{}}$

$b_2=\frac{-2\mathrm{Sw}\cot \mathrm{\&alpha;}+6h}{{\mathrm{Sw}}^2}---\left(5\right)$

Wherein, above-mentioned facewidth Sw can be calculated by aforesaid module m, and its formula is as shown in the formula (6):

$\mathrm{Sw}=\frac{\mathrm{\&pi;}\&CenterDot;m}{2}---\left(6\right)$

If desire the external diameter O of Generating gear _dWith root diameter R _dFor known, can calculate pitch diameter P respectively by following formula (7), (8) _dThe dark h of full-depth tooth.Pitch diameter P _dBe external diameter O _dWith root diameter R _dMean.By default helixangle _pWith number of teeth n collocation pitch diameter P _d, can calculate module m by formula (1).

$P_d=\frac{O_d+R_d}{2}---\left(7\right)$

$h=\frac{O_d-R_d}{2}---\left(8\right)$

In addition, formula (6) then can draw the facewidth Sw of basic rack 15 on nodel line 20.With facewidth Sw, the dark h of full-depth tooth and pressure angle α difference sleeve type (4) and formula (5), can obtain cubic curve 21, this cubic curve of mirror can obtain to revise basic profile of tooth 22.Step c copies this and revises basic profile of tooth 22 and obtain complete correction tooth bar, and utilizes the flank profil 40 of this correction tooth bar generate one gear.Because utilizing the flank profil 40 of tooth bar Generating gear is a known technology, does not therefore add at this and give unnecessary details.Among Fig. 7 and illustrate and the flank profil 40 of institute of the present invention Generating gear can allow a tolerance nargin T, be about about 5% of the dark h of full-depth tooth.

The method of the flank profil of formative gear of the present invention can be applicable to form the flank profil of parallel axes spiral gear.

The present invention also proposes a kind of gear 30, and the flank profil 40 of this gear is to utilize said method to form, and comprises the tooth portion 31 of at least one engagement corresponding gear, and it is characterized in that: the Line of contact 32 of this gear 30 is a level and smooth continous curve.As shown in Figure 8, this gear 30 can be used for rotary gear pump.Among the above-mentioned embodiment, the pressure angle α of this basic rack 15 is in the time of 22 ° to 28 °, and the dark h of the full-depth tooth of this gear is good when being less than or equal to 1.5 times of gear m, therefore when 30 engagements of two gears, can not produce sealing 14.

The gear 30 that comprises seven tooth portions with Fig. 8 is example, utilizes the formed gear train of the present invention, and the Line of contact 32 when it rotates is a level and smooth continous curve, and in the time of so can avoiding pumping, delivery pressure produces wave phenomenon.

Following table 1-1 invests the mode of execution most end of this specification to showing the parameter example that 12-2 is one to 12 tooth portion of gear tool, does not produce sealing 14 when these gears are meshing with each other; Wherein in above-mentioned table, true origin is positioned on the pitch circle center of circle of this gear, and coordinate (X Y) depicts the flank profil of this gear.Seven gears with table 7-2 are example, the operating condition that the gear engagement time does not produce sealing 14 as Fig. 9-1 to shown in Fig. 9-4.

On the other hand, utilize the present invention to form the gear of flank profil, can be a parallel axes spiral gear.These gears can be applicable to rotary gear pump, or preferably, for delivery of liquid, for example are the outward rotation type gear pump of helical tooth wheels, or a rotary positive displacement gear pump.

The above only is the preferred embodiments of the present invention, and purpose does not lie in the claim protection domain of limitation patent of the present invention, and the equivalence that all utilizations specification of the present invention and graphic content are done changes and modifies, and all should be contained in the scope of the present invention.

Table 1-1

Table 1-2

Table 2-1

Table 2-2

Table 3-1

Table 3-2

Table 4-1

Table 4-2

Table 5-1

Table 5-2

Table 6-1

Table 6-2

Table 7-1

Table 7-2

Table 8-1

Table 8-2

Table 9-1

Table 9-2

Table 10-1

Table 10-2

Table 11-1

Table 11-2

Table 12-1

Table 12-2

The proper noun contrast between Chinese and English

Rotary gear pump (rotary gear pump)

Driving gear (driving gear)

Driven gear (driven gear)

Tooth portion (tooth)

Flank profil (tooth profile)

Tooth bar (rack)

Generate (n.generating v.generate)

Involute gear (involute gears)

Involute (involute)

Root circle interior angle (root fillet)

Bizet circle exterior angle (tip rounded)

Line of contact (path of contact)

Pumping (pumping)

Fluctuation (ripple) [the unsettled pressure of output terminal 5 output devices fluctuations (ripple)]

Crown (addendum)

Tooth root (dedendum)

Sealing (encapsulation)

Module (module)

Pitch diameter (pitch diameter) Pd

Pitch circle (pitch circle)

Helix angle (helix angle) β p

Right angled coordinates (Cartesian coordinates, (Xr, Yr))

Initial point (origin) Or

Nodel line (pitch line)

Conllinear (collinear)

Tooth depth (rack height) h

Pressure angle (pressure angle) α

External diameter (outside diameter) Od

Root diameter (root diameter) Rd

Tolerance (tolerance)

Outward rotation type gear pump (external gear pump)

Parallel axes spiral gear (helical gear)

Rotary positive displacement gear pump (rotary positive-displacement pump)

Cubic curve (cubic curve)

Basic rack (standard rack)

Revise tooth bar (amended rack)

Claims (3)

1. the method for the flank profil of a formative gear is characterized in that, comprises step:

A. according to a module of desiring Generating gear, obtain a basic rack (15), a basic profile of tooth (16) of described basic rack (15) comprises a side (17), a bizet (18) and a root (19);

B. set up a right angled coordinates (Xr, Yr), the true origin of described right angled coordinates is positioned at the center of the facewidth of described basic profile of tooth, described desire Generating gear has one and revises basic profile of tooth, the basic profile of tooth of described correction is expressed with a cubic curve, and described cubic curve comprises the curve section that is positioned on the Xr axle, and (xr1 is yr1) with the curve section (xr2 that is positioned under the Xr axle, yr2), represent with following formula respectively:

x _r1＝u

y _r1＝a ₁u ³+b ₁u ²+h/2 0≤u≤Sw/2 (1)

x _r2＝u+Sw

yr ₂＝a ₂u ³+b ₂u ²-h/2 -Sw/2＜u≤0 (2)

Wherein, Sw is the facewidth of described basic profile of tooth, and h is that the full-depth tooth of described desire Generating gear is dark, and a1, a2, b1, b2 are coefficient;

C. define described cubic curve and described basic profile of tooth is tangential on described root mid point (0, h/2), described side mid point (Sw/2,0) and described bizet mid point (Sw,-h/2) three point of contacts, with coordinate (0, h/2), (Sw/2,0) and (Sw, the formula (1) of-h/2) substitution step B obtains described coefficient a1, a2, b1, b2 with (2), represents with following formula respectively:

$a_1=\frac{-4\mathrm{Sw}\cot \mathrm{\&alpha;}+8h}{{\mathrm{Sw}}^3}$ $b_1=\frac{2\mathrm{Sw}\cot \mathrm{\&alpha;}-6h}{{\mathrm{Sw}}^2}---\left(3\right)$

$a_2=\frac{-4\mathrm{Sw}\cot \mathrm{\&alpha;}+8h}{{\mathrm{Sw}}^3}$ $b_2=\frac{-2\mathrm{Sw}\cot \mathrm{\&alpha;}+6h}{{\mathrm{Sw}}^2}---\left(4\right)$

Wherein, α is the pressure angle of described basic rack;

D. the formula (3) of known described pressure angle, the dark and described facewidth substitution of described full-depth tooth step C is tried to achieve described coefficient a1, a2, b1, b2 with (4), and the formula (1) of described coefficient a1, a2, b1, b2 substitution step B is obtained the basic profile of tooth of described correction with (2);

E. copy the basic profile of tooth of described correction (22) and get a correction tooth bar, utilize the flank profil (40) of described correction tooth bar generate one gear.

2. the method for the flank profil of formative gear according to claim 1 is characterized in that, described pressure angle is between 22～28 degree, and described full-depth tooth is less than or equal to 1.5 times of described module deeply.

3. a gear comprises at least one tooth portion (31), it is characterized in that, the flank profil (40) of described tooth portion (31) is to be formed by claim 1 or 2.

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