DD279627A1 - METHOD AND DEVICE FOR PRODUCING STRAIGHT OR CROWNED HEADDRESSES WITH LENGTH AND HEAVY BALLIFIED MODIFIED TOOTHED FLANKS - Google Patents

Abstract

The invention relates to a method and a device for producing straight or helical spur gears with longitudinally and vertically ball-shaped tooth flanks. According to the invention, an adjusting slide on the bobbin of a gear grinding machine is delivered radially to the workpiece axis as a function of the position of the bobbin by means of an eccentric rotated by means of an NC-controlled actuator and, at the same time, an additional movement for the rolling movement takes place via NC-controlled positioning drives.

Description

For this 5 pages drawings

Field of application of the invention

Field of application of the invention are gear grinding machines for cylindrical gears, with the application of machine tools, general engineering, gear construction and vehicle construction.

Characteristic of the known technical solutions

It is known a method (Technical Information, WMW NILES 7.03 / 88), in which a desired spherical flank surface by separate influence on height and longitudinal crowning arises. For the height crowning in the direction of the profile, a concave dressing of the effective edge of the grinding wheel and for the longitudinal crowning in the tooth longitudinal direction of the current grinding point dependent on the workpiece-related radial change in position of the grinding wheel. As a shape memory for the width crowning serves a template that scanned during the lifting movement of the grinding wheel and z. B. mechanical elements is transmitted to the bearing of the grinding spindle to initiate this radial movement in a certain ratio. The profile correction of the grinding wheel for the height crowning is formed on the flank of the gear in the same size.

Adjusting such templates for a desired longitudinal crowning is cumbersome and time consuming. Also corrections of the longitudinal crowning in unsatisfactory course can be carried out only with considerable effort. Moreover, with this method, only a constant height crown over the entire tooth width and a constant longitudinal crowning over the entire tooth height can be realized. However, the non-symmetrical deformation of the gear teeth in engagement of the teeth and the influence of the bearings require, for a high load capacity and a low-noise running of the teeth the special conditions adapted profile modifications (Weck, Mauer, VDI-Z 130) 1988 No. 6 p.97 -101 /.

Another method (DD 203836 B 23 F 5/06) uses to produce profile and longitudinal corrections a shift of the swash plate for each job in the engagement field of the toothing in dependence on the Wälzstellung and the stroke position of the plunger of the gear cutting machine. The per se known points of engagement of the teeth with the tool are summarized formula and presented in the proposal. According to the connected to the engagement field correction instructions of the flank surface a computerized decision process runs which Korrokturbet ^r AEGP for the grinding wheel axis in the operating points of the grinding wheel to be effective. Thus, a topographic distribution of the correction amounts in the points of the flank surface is possible.

The gear grinding machines with z. B. double bevel wheel apply for machining the flanks in the longitudinal direction of the tooth very high stroke rates for the grinding wheel bearing grinding ram. Since the highest points of a convex flank surface in the central region of the flank surface, the necessary number of strokes of the grinding spindle bearing in the processing of this surface according to the present proposal are twice as large as the number of strokes of Schleifstößeis. In addition, exactly where the flank surfaces exactly, d. H. Without corrections, to be processed, reversing movements of the drive elements for the grinding spindle bearings required. Displacements due to speed-dependent elastic deformations and looseness associated with mechanical elements are unavoidable. This creates deviations in the middle of the flank surface, which exert a disturbing influence on the engagement of a toothing. Furthermore, a device (DS 3018869 B 23 F-5/06) for generating longitudinal and profile-corrected tooth flanks on a gear grinding machine is known in which with a in the axial direction of the sanding wheel to be ground and forth longitudinal slide and a transverse thereto and movable rolling carriage a longitudinal correction template or a profile correction template is connected and trigger these stencils with the aid of probe elements and hydraulic or mechanical actuators a .Summierte axial movement of the grinding wheel.

A disadvantage of this proposal with the use of correction templates is also, as already mentioned above, that the adaptation of the templates for the realization of desired modifications is complicated and only the same longitudinal correction over the entire tooth height and the same profile correction over the entire tooth length can be effective.

The aim of the invention is to improve the allocation possibilities of different large correction deviations in the flank topography, and the avoidance of speed-dependent elastic deformations, especially in the central region of the flank surface at higher Stößelhubzahlen, to reduce disturbing influences on the meshing conditions.

Explanation of the essence of the invention

The invention has for its object to develop a method in which the frequency of the eccentric movement does not exceed the stroke frequency of the plunger of the gear grinding machine in cooperation with a designed for performing the method means of a known eccentric for radial adjustment of the grinding wheel.

It should be achieved that act in the highest position of the eccentric no moments on its actuator, its exact zero position is guaranteed in this position, any positional deviations of the actuators exert no influence on the actual position of the grinding spindle bearing and the Umkehrbowegung of the eccentric with the associated drive elements in the Hubendlagen the plunger occurs in which its torque is zero.

According to the task with respect to the method is achieved in that the grinding spindle bearing with grinding spindle and grinding wheel depending on the stroke position of the grinding wheel in the longitudinal direction of the tooth correction amounts in the sense of a Zahnlängsmodifikation and the workpiece depending on the Wälzweg performs an additional movement in the sense of a profile modification, the to the workpiece radial position change of the grinding wheel is initiated in conjunction with the angle of rotation dependent change in the radius vector sizes of an eccentric.

According to further features of the invention is thereby moved so that the extreme points of the contact lines of the grinding wheel lie with the flank surface on a curve that passes through the Tragbildzentrum the flank surface and the extreme point of the eccentric coincides with the respective extreme point of the contact line.

The inventive method is basically carried out with a straight edge generating profile of the grinding wheel. This does not exclude from departing from this principle in certain cases by the grinding wheel receives a basic profile correction, which is transferred in connection with the Zahnlängsmodifikation when engaging the grinding wheel along the contact line by a radial additional movement of the grinding spindle bearing changed to the flank of the workpiece.

All Korekturwerte for the operating points between grinding wheel and flank surface are processed in a microprocessor control so that the appropriate position assignment for the plunger, the eccentric and the workpiece rotation are maintained.

The task with respect to the device for carrying out the method according to the invention is achieved in that the rotatably mounted in the ram of the gear grinding eccentric, which acts on an adjusting slide, in which the grinding spindle is mounted, an NC-controlled actuator is associated with a displacement measuring in Connection stands and that the plunger is a Wegmeßsystem added. In this case, the plunger movement control technology is the leading axis, which follows the axis of the actuator for the eccentric in position control.

According to these statements, there are two different ways of making a topographical assignment of correction values in the points of engagement between the grinding wheel and the flank surface of the toothing. These two possibilities differ in that firstly they work with a straight edge grinding wheel profile or secondly with a curved grinding wheel profile.

In the second case, for each point of engagement of the grinding wheel with the flank surface of the toothing, the difference between the correction required at this point and the correction already present on the disc profile must be formed. The grinding wheel profile must adapt to the flank profile n.it the smallest modification. As a result of this basic profile correction on the grinding wheel, the z. B. related to a Zahnmittelschnitt, the resulting correction movements are together for Zahnlängs- and profile modification smaller than those that are necessary in the first case. Smaller correction movements are very advantageous because they allow larger Doppelhubzahlen the Schleifstößels with favorable technical and economic effects

 In the following explanations with reference to a preferred embodiment, the first case will be described in more detail.

embodiment

In the accompanying drawings show:

1: The schematic representation of a gear grinding machine with partially cut ram,

2 shows the tooth of a rack with helical teeth and straight edge profile,

3: the tooth of a rack, according to FIG. 2,

4 shows a part of the tooth of the generating rack, according to FIG. 2, FIG.

Fig. 5: the tooth of a production rack with front section in true size.

In Fig. 1, the stator 1 with rotary member 2, ram 3 and Vei carriage 4 of a grinding wheel 5 equipped as a tool gear grinding machine is shown schematically. The gear grinding machine operates in the itemized method, wherein the flanks of the designed as a double cone grinding wheel 5 ir represent connection with the lifting movement a of the plunger 3, the flank surfaces of a reference rack. The Schle .'scheibe 5 wrapped with this lifting movement and the rolling movement of the workpiece 6, the flank surfaces of the workpiece 6 a. I / as grinding spindle bearing 7 is radially displaceable in the direction of arrow b and is spring-loaded against an eccentric 8 from. The eccentric 8 is gekoppalt with an actuator 9 and a position measuring system 10. The rotation of the eccentric 8 leads to a radial change in position of the grinding spindle bearing 7. Rotary part 2 and plunger 3 are connected to a further measuring system 11 for determining the position of the plunger 3 relative to the rotary member 2. The ram drive with the measuring system 11 is the leading axis, which follows the axis with actuator 9 for a predetermined function in position control, so that hollagenabhängig for this axis in each operating point of the grinding wheel 5 in a microprocessor control prepared correction amounts in the sense of a Zahnlängsmodifikation can be added. The workpiece 6, whose flank surfaces are to be processed, is mounted on the rotary table 12, which in turn is mounted in the bottom slide 13. Rotary table 12 and bed carriages 13 are each driven by an actuator 14 and 15, which are in positional control with each other. In this case, the rotary table 12 performs a rotation about the workpiece axis 16 and the bed carriage 13 a longitudinal movement perpendicular to the plane of the drawing. The actuators 14 and 15 in position control are controlled so that they comply with the required rolling ratio for a particular workpiece. Depending on the rolling path of the bed carriage 13, the round table 12 is overridden by actuator 14 in a microprocessor control prepared correction amounts in the sense of a profile modification.

The use of an eccentric 8 for dependent on the ram stroke change in position of the grinding spindle bearing 7 has the advantages that

- In the highest position of the eccentric 8 no moments act on the actuator,

- always the exact zero position is guaranteed at the highest position of the eccentric 8,

there is a high loop, in particular also for this position of the grinding spindle bearing 7,

- In this position, the positional deviations of the actuators can not influence the actual position of the grinding spindle bearing 7,

- The frequency of the eccentric movement is not greater than the stroke frequency of the plunger 3 and

- The reverse movement of the eccentric 8 occurs with the associated drive elements in the Hubendlagen the plunger 3, where the plunger 3 has the instantaneous speed zero.

The effect of this device when using the method according to the invention is apparent from the following statements:

The following correlations exist for the length and profile modifications:

2 represents the tooth of a rack with rack profile as helical gearing. The normal section 17 of a flank surface 18 is at right angles to the reference edge line 19.

The reference edge line 19 is assigned the x-axis, the normal section 17 the / -axis and the perpendicular to the flank surface 18 the z-axis of a coordinate system KS (x, y, z), wherein the coordinate origin of the KS (x, y, z) in the center 20 of the flank surface 18 is located. In the grinding process, the flank surface 18 is described by the effective edge of the grinding wheel 5 and its stroke in the tooth longitudinal direction, wherein the operating points between grinding wheel 5 and flank surface of a workpiece 6 due to the lifting movement of the grinding wheel 5 lie on a contact line 21. As a result of the rolling movement, the contact line 21 travels over the entire flank surface 18 so that the flank surface 18 of the workpiece tooth is formed as a result of the lifting movement a of the grinding wheel 5 and the rolling movement of the workpiece 6. So the Berührungslirve 22 z. B. a dependent of Wälzweg Nachberührungslinie to the contact line 21. The contact line 21 is z. During the lifting movement of the grinding wheel 5 in the tooth longitudinal direction receives the grinding wheel δ a radial movement to the workpiece axis 16 in the direction of arrow b such that not the contact line 21, but the contact line 23 is traversed. In this case, the point 24 with respect to the point 25 with the coordinates x, y has the distance ζ from the flank surface 18. The new contact line 23 has an extreme point in the center 20. This is the highest point with respect to the flank surface 18 for the contact line 23 thus produced. The contact line 23 touches the contact line 21 in the center 20. The corrected contact line 26 has reference to the adjacent contact line 2

nowhere the distance zero, but an extreme point 27 for which the z-distance to the point 28 (x, y) becomes the smallest. For a given topography of the flank surface 18, the points with the smallest distance of the contact lines 22 and 26, namely 27 and 28, can be determined. The associated amounts for x, y, and ζ have the following meaning: y is a measure of the Wälzstellung, χ one for the ram position with eccentric zero (extreme) and ζ is a measure of the rolling correction, the z. B.

can be performed by the bed carriage 13. In the case of spur toothing, the point 28 coincides with the normal section 17.

If the topography of the flank surface 18 is known, then the lines of contact 26 can be determined with the location of the extreme points and with the associated z-magnitude, so that they can be processed in a microprocessor control for the associated axes.

The employed considerations are based on the following geometric relationships:

The normal section of the flat flank surface 18 is at right angles to the reference edge line 19. The straight line 29 is the normal in the center 20 of the flank surface 18.

The basic idea of a flank surface modification is explained on a simple example of a convex flank surface.

3 corresponds in the illustration of FIG. 2.

In order to be able to describe a crowning of the generated flank surface, it is given a rectangular coordinate system KS (x, y,

z) as in Fig. 2 so that its origin coincides with the center 20 and its x-axis coincides with the reference edge line 19. The y-axis lies in the plane of the flank surface 18 and the z-axis of the KS (x, y, z) is identical to the straight line 29. In the case of a curved flank surface, the xz-Ebone of the KS (x, y, z) intersects this surface in the contact line 30 and the yz-plane in the contact line 31. The contact line 30, the width crowning and the contact line 31, the high crown of the flank surface to be generated ,

In the simplest case, the generating flank surface can be determined using the equation

u = mathem. parameter

ζ = ux ² + vy ² (1)

ν = mathem. parameter

represent. In this case, height and Bre'tenbaliigkeit show a parabolic course. The sectional curves of the modified flank surface with a plane cut perpendicular to the z-axis are ellipses. In the case of non-pressurized loading, such flank surfaces of a pair of wheels produced in this way contact one another punctiformly in the center 2C. As the load increases, an ellipsoidal contact pattern arises that is related to equation (1).

The contact line 21 moves in the course of the rolling movement over the entire flank surface 18. Their current position is dependent on the relative position between generating and generated flank surface. The contact line 21 should have the equation

y = mx + n. m = increase (2)

The parameter η indicates the respective intersection of the contact line 21 with the y-axis as a coordinate section in continuous rolling motion. For Fig. 3, η = 0.

The plane defined by ζ and the contact line 21 intersects the generating flank surface in the contact line 23:

ζ = ux ² + ν (m ² x ² + 2 mnx + n ² )

(3) ζ = vn ² + 2 vmnx + (u + vm ² ) x ²

This is a 2nd order polynomial dependent on η, that is, η. H. from the intersection of the contact line 21 with the y-axis. This polynomial can be used to control the movement in the z-direction, so that the contact line 22 can be imaged. All these curves of the contact lines 23; 30; 31 have Extiempun.:te E. For the situation in Fig. 3, this extreme point E coincides with the center 20, since here η = 0 applies. The extreme points E are obtained from (3) for dz / dx = z '= 0. It is:

z '= 2 Vinn + 2 (u + vm ² ) χ = 0

vm ...

x = j-n. (4)

u + vm

Equation (4) is a straight line 32 passing through the center 10, that is, all extreme points E of the corrected contact lines 26 (Figure 2) lie on this straight line 32 as the rolling motion progresses (Figure 3).

Equation (4) in (3) provides, for the extremum E, the value ζ as a function of the parameter n. The equation (2) in conjunction with (4) indicates the y-value for the extreme point E.

The contact line 21 extends through the angle y inclined to the reference edge line 19. The parameter m in equation (2) is the same

the amount of tan γ. To determine tan y, the following considerations are required. FIG. 4 shows a part of a tooth of the production rack according to FIG. The reference point is the center 20, in which also the origin of the KS (x, y, z) according to FIG. 2 is located. By the Bezugsflanklir.ic 1 a is the rolling plane 33, which also includes the Wälzgerade 34. The rolling line 34 is always parallel to the workpiece axis 16 and closes with the reference edge line 19, the helix angle β. The normal of the flank surface 18 is aisle 29 about the Normaieingriffswinkel α η inclined to Wälzebeno 33. The end plane 35 is the position vector W associated with the amount of 1 and its coordinates ₍ based on

the KS (x, y, z) indicated. Thus is

fcos β

V sin β · sin On

I -sin G · cosa _n

The position vector Z of the flank surface 18 is the amount 1

The straight line 36 is the front profile of the production rack with the vector S. This is obtained as the ultimate product of W and Z. Thus ^? st

i-sinβsina _n cos β 0.

Normal section 17 and straight line 36 of the flank surface 18 include the angle η. From S you win:

tann, = -tan · sina _n (5)

The vector S is at the same time position vector of the engagement plane of the toothing

[sense S = j cosn

I ⁰ -

The angle γ, which includes the contact line 21 with the reference edge line 19, results as the ultimate product B from S and Z.

/ cos η B = J meaning

L ⁰ ·

That is, the angle y has the same size as η, but is offset by 90 °. For the increase m of the contact line 21 according to equation (2), the following applies:

m = tany = tansssina _n (6)

Fig. 5 is an illustration of a teeth of the generating rack, in which the front section of the teeth occurs in true size. With a rolling feed h, the origin of the KS (x, y, z) shifts in the drawing plane together with the tooth from the center 20 to point 37. This results in the coordinate section n acc. Fig. 5 in dependence on the rolling feed h.

, sina _n = h (7)

cos β For straight toothing (β = 0 °), m = 0, and equation (3) takes the following form:

(8th)

The solution shown here is generalizable in that, for the equation (2), instead of the quadratic expressions in χ and y, a polynomial of higher degree is used for the variables χ and y, e.g. B.

r = U ₀ + u, x + U ₂ X ² ... + UpX ^p + V ₀ + viy + v ₂ y ² ... + ν _ρ ν ^μ (9)

The further procedure is in principle the same as indicated for formula (1). You get again the extreme points E as a function of the parameter n, only that now these extreme points lie on a curve (p-1) th degree. Thus, the extreme points E with respect to the center 20 can be determined. If an arbitrary topography Flankonfläche be achieved, then also z. For example, the constants v ₀ ... v _p

the variable y be subjected to a change as a function of the parameter n. Of course, it is also possible to relate the correction values directly to the contact lines of the flank surfaces.

Mathematical connections

The flank surface normals along the contact line ζ = f (x, y) always intersect the grinding wheel axis at one point.

This point sequence is in the first approximation an equidistant to the contact line of the flank surface and determines the position and size assignments between ram stroke and eccentric.

The equidistant has the function with the coordinate q, which extends from the center 20 to the point 38, or with respect to the reference edge line 19 to the point 39.

ζ = Wo + Wiq + w ₂ q ² + ... w _p q ^p (10)

The position of the equidistant includes certain position assignments of the eccentric 8. The following applies to the eccentric function:

ζ = (1-cos (p) e I e = eccentricity (11)

Depending on the path of the grinding wheel, the angle φ is thus obtained:

cos (p = 1 (where + Wiq + w ₂ q ² + ... w _p q ^p ) (12)

Claims (6)

1. A method for generating straight or helical spur gears with longitudinally and höhenballig modified tooth flanks on tooth flank grinding machines in which the tooth flank surfaces are produced in the longitudinal direction and by a relative rolling movement of the workpiece in the profile direction using a trained as a double-cone grinding wheel by the lifting movement of a plunger , characterized in that the grinding spindle bearing (7) with grinding spindle and grinding wheel (5) in dependence of the stroke position of the grinding wheel (5) in the longitudinal direction of the tooth correction amounts in the sense of a tooth longitudinal modification and the workpiece (6) as a function of Wälzweg a Zusatzwälzbewegung in the sense a profile modification executes. 2. The method according to claim 1, characterized in that the workpiece (6) radial length change of the grinding wheel (5) is introduced in conjunction with an eccentric (8). 3. The method according to claim 1 and 2, characterized in that the extreme points (E) of the contact lines (21; 22; 23) of the grinding wheel (5) lie with the flank surface (18) on a curve passing through the support image center (20). the flank surface (18) goes and the extreme point of the eccentric (5) coincides with the respective extreme point (E) of the contact line (21; 22; 23). 4. The method according to claim 1 to 3, characterized in that the grinding wheel (5) receives a basic profile correction, "3 in conjunction with the Zahnlängsmodifikation when engaging the grinding wheel (5) along the contact line by a radial additional movement of the grinding spindle bearing (7) changed the flank of the workpiece (6) is transmitted. 5. The method according to claim 1 to 4, characterized in that the correction values for the operating points between grinding wheel (5) and flank surface (18) are processed in a microprocessor control so that the corresponding position assignment for plunger (3), eccentric (8) and Workpiece rotation are maintained. 6. Device for generating straight or helical spur gears with longitudinally and höhenballig modified tooth flanks, in which the rolling movement for the workpiece by rotating a rotary table and linear displacement of a bed carriage by means of NC-controlled actuators and the grinding spindle bearing is arranged in a Verstellschlitten, which is mounted adjustably in guides in the ram of the gear grinding machine by a rotatable eccentric to the workpiece axis, characterized in that the eccentric (8) is associated with an NC-controlled actuator (9) which is coupled to a position measuring system (10) and the plunger (3) a position measuring system (11) is added, wherein the plunger movement is the leading axis, which follows the axis of the actuator (9) for the eccentric (8) in position control.