CN104439530A - Undercutting machining method for extra-large-pressure-angle transmission gear - Google Patents

Abstract

The invention belongs to a machining technology for a gear, and relates to an improved undercutting machining method for an extra-large-pressure-angle transmission gear. The undercutting machining method is characterized by including the following steps that rough gear hobbing is performed; a tooth root undercutting circle is machined. According to the improved undercutting machining method for the extra-large-pressure-angle transmission gear, designing, manufacturing and machining periods of a tool are greatly shortened, machining efficiency is improved, and the machining cost is lowered.

Description

A kind of excess pressure angle travelling gear is uprooted processing method

Technical field

The invention belongs to gear machining technology, relate to the improvement of processing method that a kind of excess pressure angle travelling gear uprooted.

Background technology

The application of roller gear in aero-engine field is gradually to the design of gears in large load, minor structure, for improving the flexural strength of gear, the pressure angle of gear is increasing gradually, and for improving the fatigue resistance of gear, the tooth root portion of gear does not carry out grinding.Because after the flank of tooth of gear carries out carburizing, Quenching Treatment, there is the surface of one deck high pressure stress on heat treatment surface, and in working gear, it can improve the fatigue resistance of gear greatly.The tooth root structure of certain type excess pressure angle travelling gear is see Fig. 1, its pressure angle is 25 ° ~ 30 °, tooth root is uprooted radius of circle r=0.5mm ~ 1mm, and tooth root circle of uprooting passes through radius of a circle R=20mm ~ 100mm mutually with the flank of tooth, and gear teeth face is δ relative to the uproot projection amount of round tangent line of tooth root.Current processing method is: to uproot processing to gear according to the gear hobbing cutter of the geometric parameter design specialized of gear.Its shortcoming is: the design difficulty of hobcutter is large, and the cycle of the Design and manufacture of cutter is very long, and different parts needs to use different cutters, and make processing cost high, the process-cycle is long, and working (machining) efficiency is low.

Summary of the invention

The object of the invention is: the excess pressure angle travelling gear proposing a kind of improvement is uprooted processing method, to shorten the design of cutter, manufacturing cycle and process-cycle, improve working (machining) efficiency, cut down finished cost.

Technical scheme of the present invention is: a kind of excess pressure angle travelling gear is uprooted processing method, the pressure angle of the travelling gear processed is 25 ° ~ 30 °, tooth root is uprooted radius of circle r=0.5mm ~ 1mm, tooth root is uprooted to justify and is passed through radius of a circle R=20mm ~ 100mm mutually with the flank of tooth, gear teeth face is δ relative to the uproot projection amount of round tangent line of tooth root, and the step of processing is as follows:

1.1, thick gear hobbing process: carry out gear hobbing process to gear blank, the transverse tooth thickness of gear blank is worked into the requirement that drawing specify, forms semi-finished product gear, and the root radius of semi-finished product gear is greater than tooth root and uproots to justify and pass through radius of a circle mutually with the flank of tooth;

1.2, process tooth root to uproot circle: to uproot circle with one of following method processing tooth root:

1.2.1, grinding-shaping method processing: be installed on gear grinding machines by semi-finished product gear, to uproot circle with formed grinding wheel processing tooth root, the computational methods of formed gear geometric parameter are as follows;

$W=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))...\left[1\right]$

In formula: W is the width of emery wheel, R be tooth root uproot circle pass through diameter of a circle mutually with the flank of tooth, S is the reference circle transverse tooth thickness of gear, M is the modulus of gear, Z is the number of teeth of gear, and α j is that tooth root circle of uprooting passes through mutually with the flank of tooth and justifies the pressure angle located, and α is the nominal pressure angle of gear;

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))...\left[2\right]$

Wf is the space width on root diameter of gear, and df is the root diameter of gear, and α f is the pressure angle at root circle place; The arc radius at emery wheel edge is r;

1.2.2 the geometric parameter of emery wheel, is appraised and decided: W and Wf substitution formula [3] and formula [4] are appraised and decided, if meet formula [3] and formula [4], assert that the geometric parameter of emery wheel is qualified, carry out tooth root with this geometric parameter trimming wheel and to uproot round processing;

W≥2r〃min；……………………………[3]

W-Wf≥0.05；……………………………[4]

Otherwise, assert that the geometric parameter of emery wheel is defective, grinding-shaping method processing method can not be adopted to process;

1.2.2, the milling method of forming processing: semi-finished product gear is installed on milling machine, with special-purpose milling cutter to gear carry out tooth root uproot circle processing;

The computational methods of special-purpose milling cutter tool width and point of a knife fillet are:

$\mathrm{Wd}=\frac{\mathrm{R\π}}{Z}-R(\frac{s}{M-Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))...\left[5\right]$

In formula, Wd is the width of special-purpose milling cutter;

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-\mathrm{df}(\frac{s}{M-Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))...\left[6\right]$

1.2.3 the geometric parameter of special-purpose milling cutter, is appraised and decided: W and Wf substitution formula [7] and formula [8] are appraised and decided, if meet formula [7] and formula [8], assert that the geometric parameter of special-purpose milling cutter is qualified, manufacture special-purpose milling cutter with this geometric parameter and carry out tooth root and to uproot round processing;

Wd≥2〃Rmin……………………………[7]

Wd-Wf≥0.04……………………………[8]

Otherwise, assert that the geometric parameter of special-purpose milling cutter is defective, milling method of forming processing method can not be adopted to process; Need the gear hobbing cutter of design specialized to carry out tooth root to uproot round processing.

Advantage of the present invention is: the excess pressure angle travelling gear proposing a kind of improvement is uprooted processing method, substantially reduces the design of cutter, manufacturing cycle and process-cycle, improves working (machining) efficiency, reduce processing cost.One embodiment of the present of invention, prove through test, certain type Gear Root round process-cycle of uprooting shortens more than 60%.The tool expense of single-piece saves more than 5000 yuan.

Accompanying drawing explanation

Fig. 1 is the tooth root structural representation of certain type excess pressure angle travelling gear.

Fig. 2 adopts grinding-shaping method to carry out the schematic diagram processed.

Detailed description of the invention

Below the present invention is described in further details.See Fig. 1,2, a kind of excess pressure angle travelling gear is uprooted processing method, the pressure angle of the travelling gear processed is 25 ° ~ 30 °, tooth root is uprooted radius of circle r=0.5mm ~ 1mm, tooth root is uprooted to justify and is passed through radius of a circle R=20mm ~ 100mm mutually with the flank of tooth, gear teeth face is δ relative to the uproot projection amount of round tangent line of tooth root, and the step of processing is as follows:

1.1, thick gear hobbing process: carry out gear hobbing process to gear blank, the transverse tooth thickness of gear blank is worked into the requirement that drawing specify, forms semi-finished product gear, and the root radius of semi-finished product gear is greater than tooth root and uproots to justify and pass through radius of a circle mutually with the flank of tooth;

1.2, process tooth root to uproot circle: to uproot circle with one of following method processing tooth root:

1.2.1, grinding-shaping method processing: be installed on gear grinding machines by semi-finished product gear, to uproot circle with formed grinding wheel processing tooth root, the computational methods of formed gear geometric parameter are as follows;

$W=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))...\left[1\right]$

In formula: W is the width of emery wheel, R be tooth root uproot circle pass through diameter of a circle mutually with the flank of tooth, S is the reference circle transverse tooth thickness of gear, M is the modulus of gear, Z is the number of teeth of gear, and α j is that uproot circular arc and the flank of tooth of tooth root passes through the pressure angle that circle locates mutually, and α is the nominal pressure angle of gear;

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))...\left[2\right]$

Wf is the space width on root diameter of gear, and df is the root diameter of gear, and α f is the pressure angle at root circle place; The arc radius at emery wheel edge is r;

1.2.2 the geometric parameter of emery wheel, is appraised and decided: W and Wf substitution formula [3] and formula [4] are appraised and decided, if meet formula [3] and formula [4], assert that the geometric parameter of emery wheel is qualified, carry out tooth root with this geometric parameter trimming wheel and to uproot round processing;

W≥2rmin；……………………………[3]

W-Wf≥0.04；……………………………[4]

Otherwise, assert that the geometric parameter of emery wheel is defective, grinding-shaping method processing method can not be adopted to process;

1.2.2, the milling method of forming processing: semi-finished product gear is installed on milling machine, with special-purpose milling cutter to gear carry out tooth root uproot circle processing;

The computational methods of special-purpose milling cutter tool width and point of a knife fillet are:

$\mathrm{Wd}=\frac{\mathrm{R\π}}{Z}-R(\frac{s}{M-Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))...\left[5\right]$

In formula, Wd is the width of special-purpose milling cutter;

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-\mathrm{df}(\frac{s}{M-Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))...\left[6\right]$

1.2.3 the geometric parameter of special-purpose milling cutter, is appraised and decided: W and Wf substitution formula [7] and formula [8] are appraised and decided, if meet formula [7] and formula [8], assert that the geometric parameter of special-purpose milling cutter is qualified, manufacture special-purpose milling cutter with this geometric parameter and carry out tooth root and to uproot round processing;

Wd≥2〃Rmin……………………………[7]

Wd-Wf≥0.4……………………………[8]

Otherwise, assert that the geometric parameter of special-purpose milling cutter is defective, milling method of forming processing method can not be adopted to process; Need the gear hobbing cutter of design specialized to carry out tooth root to uproot round processing.

Embodiment

Part processing instance 1:

In the processing of booster pump driven gear, the parameter of gear is: the number of teeth 23, modulus 2.25, pressure angle 27.5 °, reference circle transverse tooth thickness 3.95, root diameter φ 45.9, Fillet "R" 0.5+00.3, tooth root are uprooted radius of circle R24.1max,

To the calculating of grinding wheel width W;

$W=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))=1.445$

To the calculating of the space width Wf at Gear Root circle place; Because root circle is less than basic circle, we press the space width that basic circle calculates basic circle place.

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))=0.9$

Compared by calculating above and draw

1.44≥2×0.5

1.445–0.9＝0.545

The shaping can carrying out gear is uprooted Milling Process.

Through the actual processing of part, we adopt width to be 1.2, and fillet is that the emery wheel of R0.5 is processed on molded gear grinding machine, achieve the processing of uprooting of part.

Part processing instance 2:

In the processing of mesomerism gear, the parameter of gear is: the number of teeth 57, modulus 2.25, pressure angle 27.5 °, reference circle transverse tooth thickness 4.1, root diameter φ 121.9, root fillet tooth root is uprooted radius of circle R62.15max,

To the calculating of grinding wheel width W;

$W=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))=2.88$

To the calculating of the space width Wf at Gear Root circle place; Because root circle is less than basic circle, we press the space width that basic circle calculates basic circle place.

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))=2.81$

Compared by calculating above and draw

2.88≥2×0.7

2.88–2.81＝0.06

The shaping can carrying out gear is uprooted Milling Process.

Through the actual processing of part, we adopt width to be 1.4, and fillet is that the emery wheel of R0.7 is processed on molded gear grinding machine, achieve the processing of uprooting of part.

Part processing instance 3:

In the processing of travelling gear, the parameter of gear is: the number of teeth 25, modulus 2.5, pressure angle 25 °, reference circle transverse tooth thickness 4.2, root diameter φ 55.5, root fillet tooth root is uprooted radius of circle R29.39max,

To the calculating of grinding wheel width W;

$W=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))=3.75$

To the calculating of the space width Wf at Gear Root circle place; Because root circle is less than basic circle, we press the space width that basic circle calculates basic circle place.

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))=3.24$

Compared by calculating above and draw

3.75≥2×0.8

3.75–3.24＝0.53

The shaping can carrying out gear is uprooted Milling Process.

Through the actual processing of part, we adopt width to be 1.4, and fillet is that the emery wheel of R0.7 is processed on molded gear grinding machine, achieve the processing of uprooting of part.

Claims (1)

1. an excess pressure angle travelling gear is uprooted processing method, the pressure angle of the travelling gear processed is 25 ° ~ 30 °, tooth root is uprooted radius of circle r=0.5mm ~ 1mm, tooth root is uprooted to justify and is passed through radius of a circle R=20mm ~ 100mm mutually with the flank of tooth, gear teeth face is δ relative to the uproot projection amount of round tangent line of tooth root, it is characterized in that, the step of processing is as follows:

1.1, thick gear hobbing process: carry out gear hobbing process to gear blank, the transverse tooth thickness of gear blank is worked into the requirement that drawing specify, forms semi-finished product gear, and the root radius of semi-finished product gear is greater than tooth root and uproots to justify and pass through radius of a circle mutually with the flank of tooth;

1.2, process tooth root to uproot circle: to uproot circle with one of following method processing tooth root:

1.2.1, grinding-shaping method processing: be installed on gear grinding machines by semi-finished product gear, to uproot circle with formed grinding wheel processing tooth root, the computational methods of formed gear geometric parameter are as follows;

$W=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))\·\·\·\left(1\right)$

In formula: W is the width of emery wheel, R be tooth root uproot circle pass through diameter of a circle mutually with the flank of tooth, S is the reference circle transverse tooth thickness of gear, M is the modulus of gear, Z is the number of teeth of gear, and α j is that tooth root circle of uprooting passes through mutually with the flank of tooth and justifies the pressure angle located, and α is the nominal pressure angle of gear;

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-R(\frac{\mathrm{R\π}}{Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))\·\·\·\left(2\right)$

Wf is the space width on root diameter of gear, and df is the root diameter of gear, and α f is the pressure angle at root circle place; The arc radius at emery wheel edge is r;

1.2.2 the geometric parameter of emery wheel, is appraised and decided: W and Wf substitution formula [3] and formula [4] are appraised and decided, if meet formula [3] and formula [4], assert that the geometric parameter of emery wheel is qualified, carry out tooth root with this geometric parameter trimming wheel and to uproot round processing;

W≥2r·min；……………………………[3]

W-Wf≥0.04；……………………………[4]

Otherwise, assert that the geometric parameter of emery wheel is defective, grinding-shaping method processing method can not be adopted to process;

1.2.2, the milling method of forming processing: semi-finished product gear is installed on milling machine, with special-purpose milling cutter to gear carry out tooth root uproot circle processing;

The computational methods of special-purpose milling cutter tool width and point of a knife fillet are:

$\mathrm{Wd}=\frac{\mathrm{R\π}}{Z}-R(\frac{S}{M-Z}-(\mathrm{inv\αj}-\mathrm{inv\α}))\·\·\·\left(5\right)$

In formula, Wd is the width of special-purpose milling cutter;

$\mathrm{Wf}=\frac{\mathrm{R\π}}{Z}-\mathrm{df}(\frac{S}{M-Z}-(\mathrm{inv\αf}-\mathrm{inv\α}))\·\·\·\left(6\right)$

1.2.3 the geometric parameter of special-purpose milling cutter, is appraised and decided: W and Wf substitution formula [7] and formula [8] are appraised and decided, if meet formula [7] and formula [8], assert that the geometric parameter of special-purpose milling cutter is qualified, manufacture special-purpose milling cutter with this geometric parameter and carry out tooth root and to uproot round processing;

Wd≥2·Rmin……………………………[7]

Wd-Wf≥0.04……………………………[8]

Otherwise, assert that the geometric parameter of special-purpose milling cutter is defective, milling method of forming processing method can not be adopted to process; Need the gear hobbing cutter of design specialized to carry out tooth root to uproot round processing.