DE4207511A1 - Grinding process for correcting involute profile of internal gear - depends on use of grinding tool in form of convex globoid worm which is meshed with rack formed dresser to produce corrected involute and then used to grind gear - Google Patents

Abstract

The grinding tool (1) is in the form of an internally meshing convex globoid worm. The final profile of the tool is generated by engagement with a dressing tool in the form of a rack (3) with a diamond coated tooth surface. The amount of involute profile correction produced is determined by adjustment of the dressing tool towards or away from the grinding tool. To grind the teeth of the internal gear the grinding tool is lowered into engagement with the gear and rotated about its axis at speed W1 whilst the workpiece rotates about a second normal axis at a relative speed W2 dependent on the number of gear teeth. ADVANTAGE - Method can be economically applied to small batch production.

Description

The method according to the invention for grinding involute teeth with the aid of an internally screwing, convex globoid screw worm as a re-shapeable grinding tool ( 1 ) represents a more economical grinding correction method for hardened internal gears for individual workpieces than the known part method. The grinding worm is made from a known grinding wheel ring according to DIN 69100. Their grinding screw threads are z. B. diamond-coated racks according to DIN 867 by screw rolling the convex grinding worm relative to the rack.

It is known to use larger numbers of hardened internal gears an uncorrectable, diamond-coated grinding worm to correct for internal gears for special planetary gear z. B. is this uneconomical due to small lot size. Therefore, to increase the Cost-effectiveness for this manufacturing area the Ver invention drive suggested.

This is based on any straight or oblique involute toothing according to a reference profile according to DIN 867. To several at the same time Tooth flanks of an internal gear wheel grinding with a globoid screw (not zend), a convex globoid screw is proposed grinding worm analogous to DE 36 42 816 A1 as an internal screw, modified Globoid screw, from z. B. known grinding wheels according to DIN 69100 ago posed to use, and that the screw connection up to z. B. 16 screw grinding flanks is expanded. According to the procedure, it is required the rotating grinding worm with modified involute envelope grinding to provide screw gears, which envelop the involute tooth profile flanks grind on a variable line of contact. To be a casual distortion when dressing or inserting the grinding screw gears To avoid this is determined by one of several factors Way to move stationary or move controlled.  

These procedural operating conditions are:

• 1. In the convex surface of the rotating grinding globular worm ( 1 ) by means of a relative hobbing tool according to DIN 867 as a multi-toothed, diamond-coated stationary rack rotated by the swivel angle δ on the infeed radius in the plane of rotation up to the partial circle coverage between the workpiece and the grinding globoid worm by the stationary and cut a radial relative delivery of the latter.
• 2. In this profiling cut, the grinding globoid worm ( 1 ) rotates with angular velocity W ₁ around its own axis in the center plane of rotation and with the relative workpiece angular velocity W ₂ normally in the center relative to it around the workpiece axis with a variable feed radius.
• 3. The diamond-coated dressing rack tool ( 3 ) as a straight shaped involute reference profile is tangentially longer and normally wider than the screw contact elbow. Thus, only a screw-rolling, radial infeed of the grinding worm body without longitudinal movement is to be carried out for inserting the profile.
• 4. After they have been profiled, the stationary grinding worm becomes radial withdrawn, into the stationary workpiece, thereby relatively by Δβ pivoted into it, in order to then center the workpiece tooth flanks Align the grinding screw profile for the first sanding.
• 5. In the case of globoid involute screw grinding, the grinding longitudinal tool movement one of the sum of the flank pitch β and the Tool pitch β₀ dependent, normal swiveling Δδ around the workpiece axis derived.
• 6. For subsequent reprofiling of the Globoidschleifschraubflanken radially moved back Schleifgloboidschnecke (1) movement by longitudinal brought to the dressing tool (3), while normal gradient-dependent pivoting about the workpiece axis, then after completion of the longitudinal movement radially infed, the Schraubschleif profilhüllflanken under relative rotation ratio W ₂ = W ₁ · Z ₁ / Z ₂ resharpened.
• 7. The position and the angular position of the dressing tool ( 3 ) determines the involute flank shape of the tool teeth. It can be determined by the radial adjustment of the same at a suitable pitch angle by the amount of tooth correction.
• 8. The relative swivel angle Δδ around the workpiece axis is a function the tooth pitch angle β plus grinding wheel pitch β₀ to the rotation plane and the size of the linear longitudinal movement of the grinding wheel axis parallel to the workpiece axis at a distance.
• 9. With relative grinding speed and wheel colliding mid-section plane with the plane of rotation can be with radial infeed the grinding wheel rotation axis is a hardened, concave screw Involute globoid helical gearwheel be corrected enveloping. These concave internal screw with a convex globoid screw the lines of contact between the tooth flanks all the more on the medium swivel the cutting plane, the smaller the slope differences are or the smaller the ratio of the distance between the grinding wheel rotation axis from the workpiece axis to the average effective grinding radius. Before Exposure of such a wheel pair is the exact match of Gauge grinding worm and globoid worm by the same manufacturing parameters with the same dimensions and use of the same reference profiles according to DIN 867.
• 10. By changing the pressure angle α = 20 ° according to DIN 867 in the profile Normal cutting of the grinding tool can make the hydrodynamic lubrication increased pressure and the local normal radius of curvature generating workpiece flank curvatures enlarged and the Hertzian Pressing can be spread over a larger area.
• 11. By reducing the center distance a d. H. through optimized approximation of the grinding tool radii to the corresponding wheel radii swivel the grinding contact sleeve lines towards the middle section plane, so that the surface areas of contact are enlarged and the load is increased the abrasive grain layer is reduced.

Image description

Fig. 1 shows schematically a convex grinding tool ( 1 ) in profile-cutting screw-rolling engagement with the dressing tool ( 3 ) outside the workpiece z. B. as a stationary internal spur gear ( 2 ). The straight dividing line of the rack and pinion tool ( 3 ) touches the cylindrical pitch circle jacket in P at x = 0 and is rotated by the swivel angle δ from the relative W ₂ rotation plane. The rack tool ( 3 ) can be moved radially with ± x to correct the profile.

Fig. 2 shows schematically according to the method, the grinding tool (1) delivered to the workpiece. The workpiece stands still while the grinding tool rotates in two normal planes in the ratio W ₁ : W ₂ = Z ₂ . To re-sharpen the grinding tool, it is subsequently rotated by means of a dressing tool by means of a linear longitudinal and radial infeed movement.

Fig. 3 shows the method according Dressing tool according to DIN 867.

Fig. 4 schematically shows a method according to the grinding head (4) to the central pivoting of the grinding tool by means of the circular arc guide (5) rotatably fixed in the grinding carriage (6) and linearly guided on the machine frame (7), grinder drive motor (8) drives over Kegelstirnradrädergetriebe grinding tool (11) on, this is positioned in the deepest grinding position and has finished grinding the internal spur gear ( 2 ), the slide ( 12 ) with a rotating plate ( 10 ) is rotatably mounted on bearings ( 11 ), slide ( 12 ) can be moved linearly to the stand ( 7 ) and Adjustable grinding tool. Dressing tool ( 3 ) connected to the turntable ( 10 ) so that it can be adjusted radially and pivotably. The grinding head ( 4 ) is supported with the help of the tailstock bearing ( 13 ).

Subject index

1 reshapable grinding tool designed as a convex internally screwing globoid screw
2 involute-shaped internal gear tooth and internal globoid gear tooth flanks
3 diamond-coated dressing tools with toothed rack reference profile according to DIN 867
4 grinding head
5 circular arc guidance
6 grinding slides
7 machine stands
8 grinding wheel drive motor
9 centering ring
10 turntables
11 pivot bearings
12 sledges
13 tailstock bearings

Sign meaning

β = helix angle
β _o = average pitch angle of the grinding profile path to the plane of rotation
δ = total swivel angle
Δδ = superimposed swivel angle
W₁ = angular speed of the grinding wheel
W₂ = relative angular velocity of the workpiece in the pitch circle
Z₁ = number of grinding tool screw turns
Z₂ = number of teeth on the workpiece
t = forehead division
d _o1 = grinding tool _{pitch circle} in the plane of rotation
d _o2 = workpiece _{pitch circle}

Claims (3)

1. Method for grinding involute teeth with the aid of an internally screwing, convex grinding globoid screw worm as a re-formable grinding tool 1 for the economic correction of hard-drawn internal gear and internal globoid tooth flanks by means of grinding wheel bodies according to DIN 69100 and using known and diamond-studded toothed rack profiling dressing tools, characterized in accordance with DIN 867 that the profiling of the konvexgloboiden screw 1 takes place schraubwälzend by their fixed radial, relative delivery to the profile tool 3 at the same time relatively rigid, gekoppel ter rotation about its rotational axis and its normal plane of rotation about the workpiece axis that, by the profiling of a modified convex Evolventenschraubhüllprofil in the grinding tool surface incised that this extends over several globoid screw revolutions, that this multi-course expansion simultaneously doubles the number of tooth fla nken involute-like envelope grinding corrected that the envelope grinding correction of the tooth flanks is only globoid screwing and not rolling, so that when the number of screw teeth Z = 1 of the grinding worm ( 1 ), the relative workpiece angular velocity W₂ is equal to the grinding tool angular velocity W₁ divided by the number of workpiece teeth Z₂ or pitch that the Linear grinding movement of the grinding tool axis as a function of the tooth pitch angle β, a rotation plane swiveling around the workpiece axis causes that after the first profiling of the convex grinding worm in relation to a specific workpiece and the central alignment of the workpiece to the grinding profile flanks, all further post-profiling and sharpening of the grinding profile flanks at constant angular speed speed and relative constant angular velocity ratio of workpiece and grinding tool is carried out that the radial displacement amount of the dressing tool Ver The extent of the involute tooth correction determines that the position of the grinding tool axis in the central section plane of a concave globoid worm wheel according to DE 36 42 816 A1 and the radial positional adjustment to the wheel pitch circle with congruence coverage with the grinding worm produces such a grinding correction of the hard-twisted globoid involute helical gear tooth flanks that produce the exact flanks with a hardened ground convex involute enveloping worm worm, provided that this was created using the same involute screw profile, which determined the parameters as the same-sized gauge block globoid worm, that with a large flank angle β to avoid multiple threads of the helical grinding threads (Z₁ <1), the rotation plane of the grinding worm direction is pivoted that the generation of the gear wheel flanks using a rack tool according to DIN 867 compliance with a certain, convex Globoidschnek ke size, and instead allows the use of grinding wheels of different radii. 2. Grinding machine according to claim 1, characterized in that its procedural construction is sub-assembly and known ten materials and processes that the control ki nematics as known using gear elements such as spur gear, bevel gear and worm gear that the fixed rotatable bearing of the rotating functional elements such as grinding wheels, workpiece plates with rolling or sliding also known bearings that the Drive energy supplied with the aid of speed-controlled three-phase motors will that linear delivery paths electromechanical and electro-hydraulic be performed with known machine elements that function dependent angular velocity relationships by means of change gears be permanently set that function-dependent superimposed swiveling movements of an adjustable guide ruler in cooperation with a rack and pinion gear, bevel pinion spur gear stage derived will. 3. Grinding machine according to claim 1, characterized in that its ver driving-based control computer-controlled according to the program takes place that the synchronization of angular speeds not mechanically son solved computer-controlled using known stepper motors is that all infeed movements are carried out by means of servo controls.