DE4313535A1 - Five-axis gear-cutting machine for producing spiral gears, and method of operating the machine - Google Patents

Abstract

Spiral-toothed bevel or hypoid gears in particular are produced according to one of the known forming or generating processes on this fully automatic, electronically controlled gear-cutting machine. Through the use of axes required solely in terms of gear-tooth mathematics, this machine, apart from the spindles for tool and work gear, only requires three axes moving during the process without restricting its function. This results in a very simple and rigid machine construction. The method according to the invention shows that the plunge movement, relatively between tool and work gear, is carried out by a rotation of the headstock, which is thereby given a double function. The sequences of movement of the machine axes as a function of time are also virtually linear in order to produce the most complicated gear tooth systems, such as form-generated hypoid pinions. A considerable improvement in the stability and rigidity of the control process of the electronic control equipment can thereby be achieved. The preconditions for a favourable dynamic behaviour of the gear-cutting machine during the machining process are created by the reduction in the movable machine parts as well as by the simplification of the kinematic sequences.

Description

The invention relates to a fully automatic gear system machine for the production of curved toothed gears according to the upper Concept of claim 1 and a method for operating the Gear cutting machine, for the production of spiral and hypoid cones wheel.

Newer gear cutting machines enable the fully automatic spa processing with the help of forehead cutter heads after a continuous part process or single part process.

Such a gear cutting machine is described in EP-A-0 355 318 ben. The motor is rotatably mounted in a roller bearing driven roller contains three more, each rotatably mounted adjusting drums, namely an eccentric, Orientation and tilt drum. Before the gearing process adjust these adjusting drums in such a way that the Drums rotatably mounted tool as the desired tool Position for cutting a gear. Furthermore are additionally the swivel table around the vertical swivel axis, the work wheel headstock radial to the swivel axis and a vertically displaceable slide (hypoid stick). All of these settings are through an electronic tax device automatically adjustable and fixable. During the Gearing process move, except the rotation of the factory stuff and work wheel, the generating drum, which is used to generate rolling gears a certain angular range around their axis ro animals and the roller, which is for every kind of gears carries out a feed movement in the machine longitudinal axis. Like this The setting as well as the gearing process is probably done with the help  a diskette used in the control device automa carried out table.

This means that ten are moving on this classic machine Liche axes are required, six of which are only used as settings axes and four as axes moved in the gearing process be set.

Gear cutting machines are known from DE-A36 43 967 and WO-A-89/01 838 became known for the same purpose, which less moved Ma machine axes and in particular no roller with inclination have facility. There are three at right angles to each other orderly machine axes, one swivel axis and two machines nominal spindles for tool and work wheel. The Wälzbewe is determined by at least two and the axis offset (hypoid) through at least one of the right-angled machine axes testifies. With control means and appropriately regulated drive The car is used for these machine axes and spindles all processes achieved. All gearing processes and Setting options for conventional machines (classic Type) are to be realized and are known as before exposed, especially the kinematic equivalent to Knife head inclination and corrections of the flank longitudinal shape, in Single flank cut, in double flank cut, etc.

The kinematic equivalent of these machines is based on the Cartesian principle that by three translational and three rotational degrees of freedom any configuration can be realized between two bodies in space, esp special for every rolling position of classic machines builds a setting of the six axes of the Cartesian Ma machine design can be calculated for the tool and work wheel take the same relative positions to each other. There this principle of a well-known mathematical rule corresponds and in machining centers and robots for a long time  is used, it can be assumed to be known. Ins A method is known from DD 26/537 C2 in particular that it enables ke on a six axis NC machine tool produce toothed gears with any flank line, which shows that on every universal machine tool with three translational and three rotatory axes Any gear with an arcuate flank line can be provided, provided there are tax resources that a ko Realize ordained movement.

It is also a gear cutting machine from EP 0501 196 A1 knows that only the "na door "toothing axes. This machine is true in contrast to the "Cartesian" machines to the special ones Adjusted conditions for the bevel gear meshing, nec However, in addition to four rotary and two translatory, axes moved in the process, another axis around the eccentric set the tool's tool life, making a total of seven measurements machine axes are required.

The invention as characterized by the features of claim 1 is used, solves the task of a fully automatic gear to create a machine with a minimum of movement Construction parts allows a particularly rigid structure and the integration of power electronics and NC-Tech nik simplified, as well as to show a procedure with which the universal use of the gear cutting machine received undiminished remains.

The advantages achieved by the invention are essential Lichen to see that the gear cutting machine according to the invention only the five axially required axes owns. In particular, the machine according to the invention has this Feature on that they have no translational axis of movement in Machine longitudinal direction required, but the plunge feed  (which has no gear mathematical meaning) and all Corrective movements in this direction are geometrically equivalent achieved by rotating the swivel table, whereby the Swivel table has a double function. All of the above Gear cutting machines point the axis in the machine longitudinal direction Axis moved in the process to realize a milling feed and correction of the flank line for each type of Bevel and hypoid gears are needed. Use these machines the swivel table axis of rotation exclusively around the required adjust the angle between the tool and the work wheel.

The elimination of another machine axis compared to the kar tesian gear cutting machine provides a very simple machine with the highest possible mechanical and kinematic stability. This simplification is achieved by eliminating the universal Character of the Cartesian six axis machine on which with suitable tools and clamping devices also any parts such as e.g. B. Housing could be edited. The invention Machine is specially designed for the production of gears especially those with a conical body and curved miger flank line adapted and corresponds to the vector math table representation of the gearing process.

Since with each of the known gear machine types only after End the piercing process the exact geometric Ver Relationships between tool and factory wheel are made, he possible rotation of the swivel table, as well as the Be movement along an additional longitudinal axis, the position changes tion of the tool relative to the work wheel with the purpose of a Grooving feed. For bevel gears, their head and foot cones point at one point (those with a proportional tooth height) results in a plunge using the swivel table rotation even a much more balanced machining of the tooth gap over the entire tooth width, resulting in an improved process dynamics and longer tool life. With everyone  their gear types do not have any disadvantages of inventions machine in accordance with the known machines.

An embodiment of the invention is described below explained in more detail by drawings. It shows:

Fig. 1 is a perspective view of a Kegelradverzahn machine,

Fig. 2 shows the control scheme for the controlled movement of the machine axes in five teeth process,

Fig. 3 is a perspective view of the triangular vector model to represent the teeth process,

Fig. 4 twisting of the vector model of Fig. 2 about the Z-axis,

Fig. 5 rotation of the vector model of Fig. 2 and 3 about the X axis,

Fig. 6 graphs with the movements of the machine axes,

Fig. 7 block diagram of the plunge movement.

Referring to FIG. 1, the generating or roll cradle is on a machine bed 10 on the one hand 11 superimposed in the direction of the double arrow A displaceable ge other hand, a spindle stock 12 about a pivot axis 13, which is the so-called bed means in Rich processing of the double arrow B pivotably supported. On the spin delstock is a work wheel spindle 15 which is rotatable about an axis 14 . On the rolling stock 11 is a vertical slide 16 in the direction of the double arrow C slidably gela and there is a tool spindle 18 rotatably mounted about the axis 17 , to which a tool 19 , for example a cutter head for cutting a bevel gear 20 is attached. According to the invention, the work wheel spindle 15 is fixedly arranged in the headstock 12 in such a way that the axis 14 intersects at a point 21 with the pivot axis 13 and the imaginary roller axis 22 .

The work wheel 20 is fastened to the work wheel spindle 15 in the usual manner (not shown here) with the aid of a tensioning device, the tensioning device ensures the correct longitudinal position (direction of the double arrow D) of the work wheel 20 , so that the tip of the reference part cone 23 is normally in contact with the The intersection of the work wheel axis 14 , the headstock axis 13 and the roller axis 22 lies at point 21 . The tool 19 is placed in the longitudinal direction of its spindle 18 (direction of the double arrow E) so that the knife tips cut the foot cone of the work wheel 15 when the headstock 12 is in the angular position at the end of the piercing process. A fine tuning of the tool 19 (in the range 0.001 to 0.1 mm) in the direction E is not necessary, since this is realized by a small additional pivoting of the headstock 12 about the pivot axis 13 , which leads to approximately the same result (the difference through this second order approximation is small). As can not only on a machine controlled in the process axis in the direction of the double arrow E, but also on a fine adjustment in this direction.

As a tool 19 , a grinding or honing tool, for example a cup wheel for a single part process, can be used ver.

The work wheel spindle 15 and the tool spindle 18 are actuated by steplessly variable-speed drives 37 and 38 , as shown schematically in FIG. 2. Their coupling takes place via a rigid electronic transmission, which is made up of the drive controllers 32 and 33 , the angle stepper sensors 42 and 43 coupled to the motors 37 and 38 and the position measuring systems 47 and 48 . The coordination of the two controlled systems of the spindles 15 and 18 with the effect of a rigid coupling is carried out by the NC axis control 25 . In the same Wei se the machine axes A, B and C, whose motors 34 , 35 and 36 are provided with the angle incrementers 39, 40 and 41 , which pass on their signals to the drive controller 29 , 30 and 31 and whose absolute position of the Measuring systems 44 , 45 and 46 is transmitted to the NC axis control 25 . The cooperation of all five axes (B, C, A, 15 and 18 ) is coordinated by the NC axis control 25 . The kinematic sequences are prepared by the control computer 24 from the input data, which have entered the memory elements of the control from a floppy disk 49 or manually via a keyboard 28 on the operating part 27 , in the form of value tables or functional equations for the NC axis control. Furthermore, the machine control has the so-called PLC part 26 , which enables the machine to be operated with coolant, chip disposal, hydraulics, etc.

An electrical control cabinet with the is not shown Control computer, which in addition to the Gear cutting machine is arranged, in particular with the help of the control computer in the gear cutting process the machine axes A and C and the two machine spindles are set automatically and regulated, d. H. directions A, B and C are also to be understood as machine axes.

FIG. 3 gives an illustration of the triangular vector model, which is used to represent the gearing process. The position shown shows the work wheel 20 with the tooth flank 51 and the calculation point 50 , as it would be attached in a gear cutting machine of classic design for gear cutting. The vector Rm connects the axis intersection 21 with the calculation point 50 , the vector connects the axis intersection 21 with the partial point 53 on the tool axis 17th The tool axis 17 is still arbitrary in space in Fig. 3, that is, it is parallel to none of the coordinate axes C, 22 or 14 .

The first rotation of the triangular vector model takes place around the work wheel axis 14 by the value TALF according to the rotation arrow until the tool axis 17 lies parallel to the plane 52 . This rotation can be realized in the gear cutting machine by rotating the work wheel spindle 15 about its axis 14 .

Fig. 4 shows the triangular model vector after rotation TALF. The tool axis 17 is now parallel to a line 55 which lies in the plane 52 and is therefore also parallel to the plane 52. With the subsequent rotation about the axis 13 by the angle TWNK according to the arrow in FIG. 4, the parallelism of the tool axis becomes 17 made with the axis 22 . This rotation is realized in the gear cutting machine according to the invention by rotating the headstock 12 about the axis 13 in the direction of the double arrow B in FIG. 1.

Fig. 5 shows the triangular vector model in the final state after the two-described distortions, that is, the tool axis 17 is parallel to the rolling axis 22, thus achieved a configuration which can be adjusted by the five axes of the gear cutting machine according to the invention.

The rolling process, which is neces sary for producing rolled toothings, can be understood in FIG. 3 by rotating the triangular vector about axis 22 (Y axis). In each rolling position, the rotations described with reference to FIGS . 3, 4 and 5 must then be carried out in order to obtain the coordinates of the axes (ie the default manipulated variables) of the gear cutting machine according to the invention, a special feature of this method being that the The position of the tool partial point 53 on the tool axis 17 , in relation to the direction E according to FIG. 5, is the same in every rolling position after the rotation into the final state, as a result of which every movement in the direction of the double arrow E (Y axis) in FIG. 5 can be saved or is not required. This relationship will be verified in the following using a numerical example.

Table 1

Numerical example

As an example, a form-rolled hypoid rite is shown in Table 1 zel with a partial cone angle (reference partial cone) DELT = 20 ° and a spiral angle BETA = 30 °. The definition of rotation matrices around the three coordinate axes of the triangular vector model is as follows:

The direction of the tool axis vector 17 in the middle rolling position shown in FIG. 3 is calculated from the inclination by the partial cone angle and by the crowning inclination (Table 1) as follows:

The tool axis vector has thus assumed the general spatial position of the tool axis 17 in FIG. 3. The first rotation TALF from FIG. 3 to FIG. 4 has a tool axis vector without a component in the X direction (axis B) as its target in order to produce parallelism to line 55 according to FIG . The calculation is as follows:

this results in

and

COS (TALF) _* K _x -sin (TALF) _* K _y = 0
and TALF = arctan (K _x / K _y ) = 4.68 °

The second rotation from FIG. 4 to FIG. 5 by the angle TWNK around the X axis (axis 13 ) is calculated as follows:

this results in

and

sin (TWNK) _* K _y1 + cos (TWNK) _* K _z1 = 0
and TWNK = arctan (-K _z1 / K _y1 ) = -22.431 °

The tool axis 17 now has only one component in the Y direction (axis 22 ):

The vector in FIG. 3 describes the position of the tool part point 53 , in the example used it has the form in the starting position:

The two twists shown must now also be on be applied:

in which

TWNK = -22.431 ° and TALF = 4.68 °

are the previously calculated values. The result is:

which also creates the connection to the machine axes A and C and the direction E. The calculation results for the beginning of the rolling, the middle of the rolling and the end of the rolling, which cause the triangular vector model to rotate about the rolling axis 22 , are then determined analogously to the calculation process shown. These results are summarized in Table 2.

Table 2

Calculation results

It can be seen in the numerical example that, in particular, the value Y in the direction E (point 53 ) remains unchanged for all rolling positions, as was already apparent from the explanations for FIG. 5. The example verifies that a displacement of the tool in the direction E relative to the work wheel does not have to be according to the invention.

Fig. 6 shows a further advantage of the method according to the invention, which is based on the simplicity of the simultaneous movements of the three gear machine axes A, B and C and the Werkradspin del 15 (the tool spindle 18 rotates at a constant angular velocity and is therefore not considered further) . In Fig. 6 a form gewälzten hypoid pinion (WT from -15 ° to + 20 °) are shown the waveforms of the rotations TALF and TWNK and the translations A and C in the form of curves in dependence on the roll angle for the entire Wälzspektrum to produce. Since the rolling movement has the importance of the reference variable, the abscissa of the diagram is identical to the time axis, ie the curves also represent path-time relationships. In addition to the constant straight line for E, which does not exist as a movement axis in the gear cutting machine according to the invention, these are Curves for the rolling element axis A and the work wheel rotation TALF almost straight, while the curves for the rolling element axis C and the headstock rotation TWNK (axis B) have continuously monotonically increasing profiles, i.e. without turning points or extreme values in the range under consideration. This is a particular advantage in relation to the dynamic behavior of the mechanical assemblies and the dynamic behavior of the electronic controller components of the control means. The ideal case for the behavior of mechanics and electronics are kinematic relationships in the form of straight lines, that is to say functions of first order, this ideal case is already very well approximated by the method according to the invention.

It is known that the rotation TALF ( Fig. 6) of the work wheel 20 to produce a rolled bevel or hypoid gear with a differential rotation and with continuous part process still with an additional rotation, the part movement must be superimposed.

Fig. 7 shows the principle of the plunge movement of the gear cutting machine and the inventive method. Fig. 7 shows the outline of the gear cutting machine (identical to the outline of the triangular vector model). A rotation in the direction B around the point 21 realizes the approach between the tool 19 and the work wheel 20th A rotation by the angle P represents the fully inserted state, as is achieved in a completely identical manner by a displacement in the direction E in machines according to the prior art. The setting at the beginning of the rolling, the middle of the rolling or the end of the rolling can be used to control in which zone of the later tooth gap (left center or right) the machining begins. In any case, the cutting begins gradually at the first contact between the tool 19 and the work wheel 20 and increases at constant angular velocity in the direction B continuously. The highest cutting performance is shortly before reaching the fully set state, which also gives an advantage for the calming of the technologically logical plunge process in dynamic terms and in terms of tool life. In the method according to the invention, the headstock 12 can be rotated about the axis 13 in the direction B for piercing at a constant angular velocity, whereas in the prior art machines a mostly accelerated piercing movement in the direction E must take place.

Claims (9)

1. Fully automatic gear cutting machine for producing gear teeth with curved teeth, in particular bevel and hypoid gears, according to a form or rolling gear process, in continuous or single-part processes, with integration of controlled and regulated drives, an electronic gear and a control computer, machine axes (A, B and C) and machine spindles ( 15 and 18 ) checked during adjustment and in the process, or moved according to predetermined kinematic laws who containing

• - a machine bed ( 10 ),
• - A on the machine bed ( 10 ) about a pivot axis ( 13 ) pivotally arranged headstock ( 12 ), which cher a work wheel spindle ( 15 ) with axis ( 14 ),
• - An arranged on the machine bed, movable rolling stock ( 11 ), with a displaceable vertical slide ( 16 ), with a tool spindle ( 18 ) rotatable therein about an axis ( 17 ),
• - Means for displacing the rolling stock ( 11 ) and the vertical slide ( 16 ) and for rotating the spindle stock ( 12 ) relative to one another,

characterized in that

• - only three machine axes (A, B and C) and two machine spindles are provided for carrying out the gearing process,
• no machine axis moved in the process is provided in the machine longitudinal direction (E) and in the longitudinal direction of the work wheel axis (D),
• - The pivot axis ( 13 ) of the headstock ( 12 ) is parallel to the direction of displacement (C) of the vertical slide ( 16 ) or parallel to the direction of displacement (A) of the rolling element ( 11 ) or between these two directions,
• - All axes (A, B and C) and spindles ( 15 and 18 ) can also be moved and regulated in the gear cutting process.

2. Gear cutting machine according to claim 1, characterized in that

• - A roller ( 11 ) has a horizontal direction of displacement device (direction A) and
• - A vertical slide ( 16 ) has a vertical direction of displacement (direction C) and
• - A tool spindle ( 18 ) in a vertical slide ( 16 ) with its axis ( 17 ) perpendicular to the displacement direction (C) of the vertical slide ( 16 ) and perpendicular to the displacement direction (A) of the rolling stock ( 11 ) is arranged,
• 3. Gear cutting machine according to claim 1, characterized in that the rolling axis ( 22 ), the work wheel axis ( 14 ) and the pivot axis ( 13 ) all intersect at one point ( 21 ).

4. Gear cutting machine according to claim 1, characterized in that the pivot axis ( 13 ) and the work wheel axis ( 14 ) are arranged perpendicular to each other. 5. Gear cutting machine according to claim 1, characterized in that the change in the longitudinal position (direction E) of the tool ( 19 ) by combining spacers between the tool's ( 19 ) and tool spindle ( 18 ) or by Ver the clamping means for fastening the tool ( 19 ) on the tool spindle ( 18 ) or by a manually or automatically operated, not moved in the process adjusting axis in the tool axis direction (E). 6. Gear cutting machine according to claim 1, characterized in that the longitudinal position of the work wheel ( 20 ) (direction D) by coordination with spacers or adjustment of the clamping means between the work wheel ( 20 ) and the work wheel spindle ( 15 ) or by a manually or automatically operated, Actuating axis not moved in the process in the direction of the work wheel axis (D). 7. A method for producing bevel and hypoid gears on a gear cutting machine according to claim 1, wherein on the tool spindle ( 18 ) a tool ( 19 ) and on the work wheel spindle ( 15 ) a work wheel ( 20 ) is arranged, characterized in that

• - A work wheel ( 20 ) is fixed in its axial position (direction D) on its spindle ( 15 ) so that the tip of its reference part cone ( 23 ) is exactly or approximately with the intersection of the work wheel axis ( 14 ), the pivot axis ( 13 ) and the rolling axis ( 22 ) coincides (point 21 ) and
• - A tool ( 19 ) in its axial position (direction E) on its spindle ( 18 ) is fixed so that the calculation point ( 50 ) is generated in the central rolling position and that for generating the complete tooth flank ( 51 ) unchanged in this axial position (direction E) remains fixed and only in the horizontal (direction A) and verti cal (direction C) direction for the purpose of rolling ver and
• - A headstock ( 12 ) while rolling a Drehbe movement TWNK about its axis ( 13 ), the size of which together with the size of a compensating rotation of the work wheel ( 20 ) around TALF about its axis ( 14 ) so that they are chosen enable the constant axial position of the tool ( 19 ) during the entire rolling and
• - During the process flow for the production of any curved toothed bevel and hypoid gears only ever maximally three machine axes (A, B and C) and two machine spindles ( 18 and 15 ) are moved.

8. The method according to claim 7, characterized in that the plunging movement which is normally neces sary before rolling takes place by rotating the headstock ( 12 ) about its axis ( 13 ), characterized in that

• - This twisting with constant angular velocity leads to a continuous increase in the chip removal volume and
• - This grooving process can be carried out in any rolling position, which does not lead to any unwanted intersections on the flank and delivers a geometrically exact result.

9. The method according to claim 7, characterized in that to achieve tooth flank corrections, the movements of all machine axes (A, B and C) and all machine spindles ( 15 and 18 ) can be superimposed with small additional movements and these additional movements with polynomials of first to sixth order, be written depending on the rolling motion. Small movements are usually defined in this context with amplitudes of about 5% of the main movements.