CN104985260B - The continuous Rolling-cut shear method of straight bevel gear - Google Patents

Abstract

A kind of continuous Rolling-cut shear method of straight bevel gear, is that cutterhead is with ω based on a kind of hypocycloid of near linear_tSpeed rotate, gear is then with ω_gSpeed rotate, the now relative motion of gear and cutter is round as a ball equivalent to cutter and gear is round as a ball makees pure rolling mesh motion.When the rolling circle radius of cutter are consistent with reference radius and equal to gear rolling circle radius half when, then the track that the point of a knife of cutter tooth is formed on gear is near linear, so as to can be used for the continuous Rolling-cut shear of straight bevel gear.With following features：Cutting Process is that continuous rolling cut has production efficiency machining accuracy higher；Also ability wet can be cut to cut, the dry processing efficiency cut is higher, flank of tooth finish is preferable, the wet straight bevel gear that obtains of processing of cutting is not strict straight line in its tooth length direction but has micro cydariform, and cydariform amount can be controlled by adjusting lathe parameter, so as to the contact area of profile shifted gear, more preferable transmission performance is made it have.

Description

The continuous Rolling-cut shear method of straight bevel gear

Technical field

The present invention relates to the processing method of straight bevel gear, the continuous Rolling-cut shear side of particularly a kind of straight bevel gear Method.

Background technology

Straight bevel gear is convenient due to its design and installation, substantial amounts of at present to apply each in each row the advantages of transmission performance is good In industry.Current processing method has forging, gear-shaping, double-cutterhead milling teeth etc..

Forging is only applicable to produce in enormous quantities, is not well positioned to meet flexible production and the increasingly production of single and mini-batch production Demand.Gear-shaping technique and Double-cutter Milling Process efficiency are low, and machining accuracy is low, and processing versatility is bad.Therefore in the urgent need to one Plant high in machining efficiency, the good processing method of versatility.

The content of the invention

It is an object of the invention to provide a kind of Gear milling process method of straight bevel gear, the method has following features：

Its Cutting Process is continuous rolling cut (face-hobbing), with production efficiency machining accuracy higher；Can Wet also ability of cutting is cut, and the dry processing efficiency cut is higher, and preferably, but requirement to cutter and lathe is higher for flank of tooth finish, wet to cut It is just the opposite.

The present invention realizes that the technical scheme of above-mentioned purpose is：

General principle of the invention is that cutterhead is with ω based on a kind of hypocycloid of near linear_tSpeed rotate, gear is then With ω_gSpeed rotate, the now relative motion of gear and cutter equivalent to radius be R_vCutter is round as a ball and radius is R_gWork Pure rolling mesh is moved.When the rolling circle radius and reference radius r of cutter_vDuring consistent and half equal to gear rolling circle radius, That is R_v=r_v=R_g/ 2, then the track that the point of a knife of cutter tooth is formed on gear is near linear, so as to can be used for straight bevel gear Continuous Rolling-cut shear.

Technical process of the invention and parameter are calculated and carried out by following steps：

First, cutting parameter is determined：According to the drawing requirement of straight bevel gear, and it is dry cut or the wet processing request cut, select Use suitable lathe, clamping mode, the type of cooling, feed speed ω_f, speed of mainshaft ω_c。

2nd, the parameter of cutterhead is calculated：

A) number of teeth of cutterhead:By the number of teeth z of work gear to be added_gAnd its root angle δ is determined, is calculated as follows：z_t/z_g= 2sin (δ) wherein z_tIt is the number of teeth of cutterhead；

B) cutter radius：First select the spherical radius R of theoretical contact point₀, the midpoint in tooth surfaces of bevel gears, i.e. R₀=R_d- B/2, in formula, R_dIt is the big end radius of bevel gear, B is the face width of tooth of bevel gear, its radius r_vScope be：

C) pressure angle of blade：The pressure angle of flank of tooth form-cutting sword is calculated as follows：α_c=atan (2r_vtanα/R₀),

Wherein α is the pressure angle of work gear to be added, is 20 degree.According to cutting method twice, then flank of tooth shaping is not involved in The pressure angle of cutting edge is desirable to be less than α_cValue to avoid interference with, according to cutting at one time method, then inside and outside knife is flank of tooth shaping Cutting edge, its pressure angle is equal to α_c。

D) inside and outside point width：Inside and outside, point width is determined according to the position of the actual cutting edge of the modulus and cutting of gear Calmly, it is necessary to calculate repeatedly in theory, to ensure that a pair of gears have good contact zone and sideshake.

3rd, cutter spacing parameter：

A) calculate nothing and transform into cutter spacing：Product shape principle and corresponding Mathematical Modeling according to cycloid, calculate without the knife for transforming into Position：If lathe is cage chair type lathe, it is without cutter spacing is transformed into：

Wherein r_iFor radially nothing transforms into cutter spacing, θ_iFor angular without cutter spacing is transformed into, r is cutterhead radial；

If lathe is cartesian co-ordinate type lathe, it is without cutter spacing is transformed into：

Wherein, H_iFor vertical nothing transforms into cutter spacing, V_iIt is level without transforming into cutter spacing.

B) initial cutter spacing is calculated：Its start angle is relative to transform into angle θ without the angle for transforming into increase or reduction one_k, exhibition Angulation θ_kDetermined by the direction for transforming into, i.e. climb cutting and upmilling, transform into angle θ_kProcessing one gear teeth of gear are as waited from engaging-in to nibbling out The angle that cage chair turns.For cage chair type lathe, initial cutter spacing is calculated as follows：

Wherein, r_c0It is initial radial cutter spacing, θ_i0It is initial angular cutter spacing.

For cartesian co-ordinate type lathe, then initial cutter spacing is：

Wherein, H_i0It is initial perpendicular cutter spacing, V_i0It is initial level cutter spacing.

4th, machine root angle parameter：The parameter is determined by the tapered tooth system of gear, to processing equal-depth teeth straight-tooth cone tooth Wheel, then the parameter is the pitch cone angle of straight bevel gear, and to processing tapered tooth straight bevel gear, then the parameter is the root cone of gear Angle.

5th, the movement relation of each axle：If lathe is the lathe of cage chair type, now the movement relation equation of each axle of lathe is

Wherein ω_gIt is gear rotational speed, ω_cIt is the rotating speed of cage chair, r_cIt is lathe cage chair radius.

Needed if lathe is cartesian co-ordinate type lathe the horizontal and vertical axle of cutterhead, i.e. X-axis and Y-axis is virtual for one is shaken Platform axle, the amount of feeding of this cage chair axle is the amount of feeding of gear generating motion.But due to cutter shaft right angle motion in its angle Do not change, so also needing to an additional differential motion, now, the movement relation equation of each axle of lathe is：

Wherein, H and V are respectively the displacement of machine tool horizontal axle and vertical axis, and t is time parameter.

6th, cutting process：According to the processing of cutting at one time method, then the lathe setting according to the 3rd step can machine straight The processing of bevel gear；Or processed using secondary cutting method, then after above-mentioned generating motion completion, by initial cutter spacing along the horizontal plane Mirror image, obtains new initial cutter spacing as follows：

Above formula corresponds to cage chair type lathe and cartesian co-ordinate type lathe respectively

Then ensure that the position of workpiece is constant, to avoid processing random tooth, inverts cutter shaft, by the motion of each axle in the 5th step Relation carries out once quick generating motion again, due to this knife cutting output very little, be optimization tooth form adjustment contact area therefore The speed for transforming into is quickly.

7th, the adjustment of lathe parameter：Due to lathe, cutterhead, frock composition error, bull wheel that actual cut goes out and steamboat Contact area is often inconsistent with theoretical calculation, and the movement relation to cutter spacing and the workpiece spindle of machine tool chief axis is finely adjusted to reach Optimal contact condition.

The present invention has following features：Its Cutting Process is continuous rolling cut (face-hobbing), with production higher Efficiency machining accuracy；Wet can cut also ability to cut, the dry processing efficiency cut is higher, flank of tooth finish is preferable, but to cutter and machine Bed requirement it is higher, it is wet cut it is just the opposite；The straight bevel gear that obtains of processing be not strict straight line in its tooth length direction and It is have micro cydariform, and cydariform amount can be controlled by adjusting lathe parameter, so that the contact area of profile shifted gear, has it There is more preferable transmission performance；Two kinds of straight bevel gears of tooth of equal-depth teeth and tapered tooth can be processed.

Brief description of the drawings

Fig. 1 is basic process principle schematic diagram of the invention.

Fig. 2 is cutter head structure schematic diagram used in the present invention.

Fig. 3 is the cutter head structure front view carried out used by cutting at one time of the invention.

Fig. 4 is the cutter head structure top view carried out used by cutting at one time of the invention.

Fig. 5 is the cutter head structure left view carried out used by cutting at one time of the invention.

Fig. 6 is the cutter head structure front view carried out used by secondary cutting of the invention.

Fig. 7 is the cutter head structure top view carried out used by secondary cutting of the invention.

Fig. 8 is the cutter head structure left view carried out used by secondary cutting of the invention.

Fig. 9 is the structural representation that last processing of the invention obtains straight bevel gear.

In figure：1. cutter is round as a ball, 2. outer knife, 3. in knife, 4. workpiece gear, 5. straight-side profile, 6. cutterhead, 7. gear rolling Circle.

Specific embodiment

As shown in figure 1, general principle of the invention is based on a kind of hypocycloid of special near linear, cutterhead is with ω_t Speed rotate, gear is then with ω_gSpeed rotate, the now relative motion of gear and cutter equivalent to radius be R_vCutter Round as a ball 1 and radius be R_gGear round as a ball 7 make pure rolling mesh motion.As round as a ball 1 radius of cutter and reference radius r_vIt is consistent and During the half of 7 radius round as a ball equal to gear, i.e. R_v=r_v=R_g/ 2, then the track that the point of a knife of cutter tooth is formed on gear is closely Like straight line, so as to can be used for the continuous Rolling-cut shear of straight bevel gear.

In reality processing, required because cutterhead and gear and the number of teeth can not strictly meet above-mentioned theory, therefore processing Tooth form is difficult to absolute straight line.True this absolute straight line is also unfavorable to transmission properties, therefore wants appropriate adjustment position Parameter, so as to be formed with the straight line flank of tooth of micro cydariform.

Optimization can make the gear of side meet the requirement of cydariform according to more than, but formed due to outer knife 2 and interior knife 3 Curved surface does not have symmetry on the gear teeth.If using only cutting at one time, the left and right tooth form of gear some differences for being permitted can be made.Therefore can It is divided into cutting at one time method and twice cutting method：Cutting at one time method only carries out cutting at one time, and the gear teeth and the left and right sides flank of tooth are by cutter Inside and outside knife it is tough once formed, the benefit of this processing method is high in machining efficiency.But a disadvantage is that the left and right flank of tooth has micro Asymmetric, contact zone is difficult adjustment；Secondary cutting method is on the basis of cutting at one time, one to be cut again using reverse knife is tough Secondary, two lateral tooth flanks of gear are formed by the outer knife 2 (or interior knife 3) of cutter, two lateral tooth flanks absolute symmetry in theory, its benefit It is full symmetric flank profil, contact zone is easily adjusted.

Process tool

In order to avoid cutterhead interference and secondary cutting, using the shape of cutterhead 6 such as Fig. 2 institutes of present invention cutting straight bevel gear Show, cutterhead 6 is regardless of rotation direction, you can fill left-handed cutterhead, it is also possible to fill dextrorotation cutterhead.Cutting at one time method is used not when processing big steamboat With the cutter head of rotation direction, tip shapes are as shown in Fig. 3, Fig. 4, Fig. 5；Secondary cutting method uses the cutter head as shown in Fig. 6, Fig. 7 Fig. 8, The cutter head can cut twice regardless of rotation direction.Machining tool

Process cutting straight bevel gear can be realized on the lathe that can realize generation processing spiral bevel gear. The structure of lathe can be cage chair formula and Cartesian coordinate type.

A pair of straight bevel gears can be processed by identical cutterhead or each processed with different cutterheads, be counted by theory Calculation obtains optimal lathe adjusting parameter, lathe adjusting parameter is modified finally according to actual contact situation, to optimize tooth The contact situation of wheel.

Can process tapered tooth straight bevel gear with the present invention can also process equal-depth teeth straight bevel gear, and processing is received The root angle adjusting parameter of lathe is determined by the root angle of gear during contracting tooth straight bevel gear, and processes equal-depth teeth straight bevel gear When lathe root angle adjusting parameter determined by the pitch cone angle of gear.

Tapered tooth straight bevel gear to be processed, its basic parameter is as shown in the table：

The Basic parameters of gear of form 1

According to above parameter, processed on 6 axle Cartesian coordinate type spiral bevel gear milling machines, added with secondary cutting method Work, its step is as follows：

1st, determine that the basic cutting parameter of gear is as follows according to processing conditions

The basic processing conditions of form 2

2nd, to calculate cutter basic parameter according to the above method as shown in the table：

The cutterhead of form 3 and insert parameters

3rd, initial cutter spacing is calculated according to the above method, the basic adjusting parameter for obtaining lathe is following (due to a pair of gears Big steamboat is just the same, therefore machined parameters are completely the same)

4th, the equation of motion for being calculated lathe is as follows：

According to above parameter, you can processing obtains the straight-side profile 5 of workpiece gear 4, finally processing obtains straight bevel gear Structure it is as shown in Figure 9.

Claims (1)

1. a kind of continuous Rolling-cut shear method of straight bevel gear, it is characterised in that：Based on a kind of hypocycloid of near linear, knife Disk is with ω_tSpeed rotate, gear is then with ω_gSpeed rotate, the now relative motion of gear and cutter equivalent to radius be R_v Cutter is round as a ball and radius is R_gGear it is round as a ball make pure rolling mesh motion；As cutter rolling circle radius and reference radius r_vUnanimously And equal to gear rolling circle radius half when, i.e. R_v=r_v=R_g/ 2, then the track that the point of a knife of cutter tooth is formed on gear is Near linear, so as to can be used for the continuous Rolling-cut shear of straight bevel gear；

Technical process and parameter are calculated and carried out by following steps：

First, cutting parameter is determined：According to the drawing requirement of straight bevel gear, and it is dry cut or the wet processing request cut, from conjunction Suitable lathe, clamping mode, the type of cooling, feed speed ω_f, speed of mainshaft ω_c；

2nd, the parameter of cutterhead is calculated：

A) number of teeth of cutterhead:By the number of teeth z of work gear to be added_gAnd its root angle δ is determined, is calculated as follows：z_t/z_g=2sin (δ) Wherein z_tIt is the number of teeth of cutterhead；

B) cutter radius：First select the spherical radius R of theoretical contact point₀, the midpoint in tooth surfaces of bevel gears, i.e. R₀=R_d- B/2, In formula, R_dIt is the big end radius of bevel gear, B is the face width of tooth of bevel gear, its radius r_vScope be：

C) pressure angle of blade：The pressure angle of flank of tooth form-cutting sword is calculated as follows：

α_c=atan (2r_v tanα/R₀)

Wherein α is the pressure angle of work gear to be added, is 20 degree；According to cutting method twice, then the cutting of flank of tooth shaping is not involved in The pressure angle of sword is taken less than α_cValue to avoid interference with, according to cutting at one time method, then inside and outside knife is the cutting of flank of tooth shaping Sword, its pressure angle is equal to α_c；

D) inside and outside point width：Inside and outside, point width is determined according to the position of the actual cutting edge of the modulus and cutting of gear, needed To calculate repeatedly in theory, to ensure that a pair of gears have good contact zone and sideshake；

3rd, cutter spacing parameter：

A) calculate nothing and transform into cutter spacing：Product shape principle and corresponding Mathematical Modeling according to cycloid, calculate without the cutter spacing for transforming into：If Lathe is cage chair type lathe, then be without transforming into cutter spacing：

$\left\{\begin{array}{c}{r}_i=r\\ {\mathrm{\θ}}_i=acos(R_0/2r_v)\end{array}\right.$

Wherein r_iFor radially nothing transforms into cutter spacing, θ_iFor angular without cutter spacing is transformed into, r is cutterhead radial；

If lathe is cartesian co-ordinate type lathe, it is without cutter spacing is transformed into：

$\left\{\begin{array}{c}{H}_i=r_{c}sin\left({\mathrm{\θ}}_i\right)\\ V_i=R_0/2\end{array}\right.$

Wherein, H_iFor vertical nothing transforms into cutter spacing, V_iIt is level without transforming into cutter spacing；

B) initial cutter spacing is calculated：Its start angle is relative to transform into angle θ without the angle for transforming into increase or reduction one_k, transform into angle θ_k Determined by the direction for transforming into, i.e. climb cutting and upmilling, transform into angle and be and wait processing one gear teeth of gear from engaging-in to nibbling out cage chair turn Angle；For cage chair type lathe, initial cutter spacing is calculated as follows：

$\left\{\begin{array}{c}{r}_{i0}=r_c\\ {\mathrm{\θ}}_{i0}=acos(R_0/2r_v)\±{\mathrm{\θ}}_k\end{array}\right.$

Wherein, r_c0It is initial radial cutter spacing, θ_i0It is initial angular cutter spacing；

For cartesian co-ordinate type lathe, then initial cutter spacing is：

$\left\{\begin{array}{c}{H}_{i0}=r_{c}sin({\mathrm{\θ}}_i\±{\mathrm{\θ}}_k)\\ V_{i0}=r_{c}cos({\mathrm{\θ}}_i\±{\mathrm{\θ}}_k)\end{array}\right.$

Wherein, H_i0It is initial perpendicular cutter spacing, V_i0It is initial level cutter spacing；

4th, machine root angle parameter：The parameter determines by the tapered tooth system of gear, to processing equal-depth teeth straight bevel gear, then The parameter is the pitch cone angle of straight bevel gear, and to processing tapered tooth straight bevel gear, then the parameter is the root angle of gear；

5th, the movement relation of each axle：If lathe is the lathe of cage chair type, now the movement relation equation of each axle of lathe is

$\left\{\begin{array}{c}{\mathrm{\ω}}_g={\mathrm{\ω}}_t{z}_t/z_g\\ {\mathrm{\ω}}_c={\mathrm{\ω}}_f\\ r_c=r_v\end{array}\right.$

Wherein ω_gIt is gear rotational speed, ω_cIt is the rotating speed of cage chair, r_cIt is lathe cage chair radius；

It is virtually a cage chair to be needed the horizontal and vertical axle of cutterhead, i.e. X-axis and Y-axis if lathe is cartesian co-ordinate type lathe Axle, the amount of feeding of this cage chair axle is the amount of feeding of gear generating motion；But due to cutter shaft right angle motion in its angle not Change, so also needing to an additional differential motion, now, the movement relation equation of each axle of lathe is：

$\left\{\begin{array}{c}{\mathrm{\ω}}_g={\mathrm{\ω}}_t{z}_t/z_g+{\mathrm{\ω}}_c/sin\mathrm{\δ}\\ v_H={\mathrm{\ω}}_c{r}_{v}cos({\mathrm{\ω}}_{c}t+{\mathrm{\θ}}_k)\\ v_V=-{\mathrm{\ω}}_c{r}_v\sin ({\mathrm{\ω}}_{c}t+{\mathrm{\θ}}_k)\end{array}\right.$

Wherein, H and V are respectively the displacement of machine tool horizontal axle and vertical axis, and t is time parameter；

6th, cutting process：According to the processing of cutting at one time method, then the lathe setting according to the 3rd step can machine straight-conical teeth The processing of wheel；Or using the processing of secondary cutting method, then after above-mentioned generating motion completion, by initial cutter spacing mirror along the horizontal plane Picture, obtains new initial cutter spacing as follows：

$\left\{\begin{array}{c}{r}_{i1}=r_{i0}\\ {\mathrm{\θ}}_{i1}=-{\mathrm{\θ}}_{i0}\end{array}\right.$

$\left\{\begin{array}{c}{H}_{i1}=H_{i0}\\ V_{i1}=-V_{i0}\end{array}\right.$

Above formula corresponds to cage chair type lathe and cartesian co-ordinate type lathe respectively；

Then ensure that the position of workpiece is constant, to avoid processing random tooth, inverts cutter shaft, by the movement relation of each axle in the 5th step Quick generating motion is carried out once again, due to this knife cutting output very little, is transformed into optimize the adjustment contact area of tooth form Speed quickly；

7th, the adjustment of lathe parameter：Due to lathe, cutterhead, frock composition error, contact of the bull wheel that actual cut goes out with steamboat Region is often inconsistent with theoretical calculation, and the movement relation to cutter spacing and the workpiece spindle of machine tool chief axis is finely adjusted to reach most preferably Contact condition.