US2991672A - Machine for the cold form generating of cylindrical workpieces - Google Patents

Description

6 Sheets-Sheet 1 July 11, 1961 A. MEYER ETAL MACHINE FOR THE cow FORM GENERATING CYL ORKPIECES INDRICAL W Filed May 15, 1959 ALBERT MEYER AND Orro WENGER C 5 m H NV M w 0 Hm w W V. B

July. 11, 1961 A. MEYER ETAL 2,991,672

MACHINE FOR THE cow FORM GENERATING OF CYLINDRICAL WORKPIECES Filed May 15. 1959 6 Sheets-Sheet 2 G ALBERT MEYER Aw OTTO WENGER I/ve/ENraRs ATTORNEYS July 11, 196 A. MEYER ETAL 2,991,672

MACHINE FOR THE cow FORM GENERATING OF CYLINDRICAL WORKPIECES Filed May 15, 1959 6 Sheets-Sheet 3 ALBERT ME YER AND Orro Mensa/2 I N VENTORS BY MMPW ATTORNEYS July 11, 1961 A. MEYER EI'AL MACHINE FOR THE COLD FORM GENERATING OF Filed May 15, 1959 CYLINDRICAL WORKPIECES 6 Sheets-Sheet 4 ALBERT MEYER AND OTTO WENGER IMVENTORS July 11, 1961 A. MEYER ETAL 2,991,672

MACHINE FOR THE COLD FORM GENERATING 0F CYLINDRICAL WORKPIECES Filed May 15. 1959 6 Sheets-Sheet 5 Flig. 12

65 Fig. 11 \1'\ g l ALBERT MEYER AND Orro WENGER INVENTORS 4 BY Wm, M WM ATTORNEYS July 11, 1961 A. MEYER EI'AL 2,991,672

MACHINE FOR THE com FORM GENERATING OF CYLINDRICAL WORKPIECES Filed May 15. 1959 6 Sheets-Sheet 6 ALBERT MEYER m OTTO u/ENGER INVEH roles By u M ATTo RNEVS Unite 2,991,672 MA CHINE FOR THE COLD FORM GENERATING F CYLINDPICAL WURKPECES Albert Meyer, Thalwil, and Dtto Wenger, Zurich, Switzerland, assignors to Maag-Zahurader 8: Maschinen Aktiengesellschaft, Zurich, Switzerland Filed May 15, 1959, Ser. No. 313,481 Claims priority, application Switzerland May 16, 1953 Claims. (Cl. 80-16) In our copending application Ser. No. 812,509, filed May 11, 1959, titled A Method for the Cold Form Generating of Cylindrical workpieces there is described a method for the cold form generating of cylindrical workpieces such as 'splined shafts, straight and helical spur gears as well as other generated profiles without cutting by means of profiling tools moved relative to the workpiece.

The method is for generating profiles on cylindrical workpieces, the profiles having raised and depressed portinuously rotating the workpiece about its central longitudinal axis simultaneously with the movement of the cold forming tools, and simultaneously moving the workpiece in the direction of the longitudinal axis to feed it between the tools.

It is a prime object of the present invention to provide a machine for carrying out said method.

To this end the machine according to the present invention comprises driving means producing a rotary, rolling motion of a workpiece to be profiled about its longitudinal axis, clamping means for clamping said workpiece, generating tools for generating the desired profile in the workpiece, tool holders adapted to receive said tools and mounted pivotally about an axis intersecting the longitudinal middle axis of workpiece, motion transmitting means connected with said driving means and adapted to move the tool holders with the tools in the direction in which profiles being produced extend and in the direction towards and away from the longitudinal middle axis of the workpiece and means for rotating and feeding the workpiece axially with respect to the Workpiece between the latter and the tools.

Other features and advantages of the invention will oecome apparent from the description, now to follow, of preferred embodiments thereof, given by way of example only and in which reference will be made to the accompanying, partially diagrammatical drawings, in which:

FIG. 1 is a partial longitudinal sectional elevation view through the axis of the workpiece and a partial cross sectional view of a tool holder, taken along line I-I of FIG. 2;

FIG. 2 is a transverse sectional view through the workpiece showing three tools and tool holders positioned around the workpiece;

FIG. 3 is partial view of the profile of the workpiece being produced;

FIG. 4 is a view similar to FIG. 2 showing a workpiece having two diametrally oppositely positioned tools for producing straight spur gears;

FIG. 5 is a longitudinal sectional view taken along line V-V of FIG. 4;

tates Patent G FIG. 6 is a plan view of the arrangement of FIG. 4 seen in the direction of the arrow VI of FIG. 4; 7

'FIG. 7 is a view similar to that of FIG. 6 showing the disposition of the tools for forming helical spur gears;

FIGURE 8 shows a partial section of an embodiment of the machine according to the invention;

FIGURE 9 is a section taken along the axis Y of a tool holder of the machine according to FIGURE 8;

FIGURE 10 shows a sectional view along the line III-III of the same tool holder as shown in FIGURE 9;

FIGURE 11 is a section taken along the line IVIV in FIGURE 10;

FIGURE 12 illustrates, in a section similar to that of FIGURE 11, a modified embodiment of the tool holder, and

FIGURE 13 illustrates diagrammatically the hydraulic-mechanical control for additional motions imparted to the tools and to the workpiece.

Generally speaking, the cold working is carried out by executing a rapid movement of the cold working tools 1 (FIGS. l-S) relative to the workpiece A in the direction X (FIG. 1) of the longitudinal axis of the workpiece, and also moving the tools in the direction Y both toward and away from the axis of the workpiece. The distance which the tools are moved toward and away from the axis of the workpiece is less than the height of the portions of the profile, as shown in FIG. 3, being formed, is. is less than the sum of the radial dimensions of the shaded areas k and m. The workpiece is also continuously rotated around its central longitudinal axis and is fed in the direction G (FIG. 1) between the tools 1. The resultant path of the tools relative to the workpiece is the path C (FIG. 1). The tools themselves can also be rotated about their own axes in the direction indicated by the arrows on the tools 1.

FIG. 2 shows how the tools may be disposed around the workpiece for producing a spur gear, each of the tools being given a motion as described with reference to FIG. 1.

FIGS. 4 6 show an arrangement of tools and the worle piece for producing spur gears. In addition to the motion given to the tools as described with reference to 'FIG. 1, the workpiece can be oscillated in its movement around its longitudinal axis, as indicated by the double arrow adjacent the large arrow indicating the rotation, and the tools can be oscillated back and forth along their own axes of rotation, as represented by the arrows u and v, this oscillation being synchronized with the rotational oscillation of the workpiece. This type of movement enables the tools to produce many diiferent sizes and shapes of teeth depending on the degree of movement.

FIG. 7 shows an arrangement of tools and workpiece similar to that of FIGS. 4-6 in which the workpiece and tool are given the same type of movement. In this instance, however, the axis of the tools has been set at a substantial angle to the longitudinal axis of the workpiece, with the result that there is formed helically extending teeth rather than straight teeth.

The apparatus as disclosed in FIGS. 8l3 is for carrying out the method as set forth above.

The machine represented in FIGURE 8 comprises a headstock 11 slidably mounted on a horizontal guide Ill and provided with a clamping device 12- for clamping a workpiece A. A tailstock 14 with a hydraulic feed 15 is mounted in the axis of rotation of and opposite to the headstock 11 and on a guide 13' aligned with the guide 10.

In a plane perpendicular to the longitudinal middle axis B of the workpiece A two rotatably mounted tool holders 3 are provided on opposite sides of said axis, the axes Y of said toolholders being exactly aligned and being situated in said plane perpendicular to the axis B of the workpiece.

A motor 16 drives two driving pistons for each toolholder 3 through a cam drive, not shown, in housing 17, said pistons imparting to the work pistons 18 and 19 respectively through hydraulic conduits 20 and 21 respectively the movement necessary for the tool. This movement is the resultant of the small oscillations in direction of the axis Y of the piston 18 and consequently of the toolholder 3 as well as oscillations in the longi tudinal direction of the toothing to be produced, i.e. in direction of the X-axis. Thus the tools 1 execute relative to the workpiece A a movement C the path of which has the shape of a fiat ellipse which rises slightly in the direction in which said tools move along the workpiece during the forming of the workpiece.

The adjustment of the tool holders in direction of axis Y for the desired diameter of the workpiece is effected by means of a toothed annular nut 24 arranged in the machine housing which housing is in the form of a pressed frame '22 with tie rods 23. The simultaneous adjustment of the opposite toolholders 3 is effected by means of a manual drive 25 which rotates gears 25a meshed with nuts 24.

A piston 62 being continually exposed to hydraulic pressure serves for the return movement of the toolholder 3 in direction of axis Y and for taking up the play.

The tools in the present embodiment are formed by generating worms having basic rack for-m (Figures 2, 4 and 10) and rotatably mounted in supports 26 with their axis perpendicular to the pivoting axis Y. Pivots 27 of said supports 26 are guided in a slide support 23 slidable on the tool holder 3 perpendicularly to the axis Y and driven by a piston 19.

The support 26 pivotably mounted in the slide support 28 permits adjusting the pitch angle of the generating worms 1. By pivoting the tool holders 3 about their axis Y the direction of movement of the slide support 28 is so adjusted that it coincides exactly with the direction which the profile to be produced extends.

The rotary motion of the generating worms 1 is transmitted from the drive shafts 34 through bevel gears 29, 3t) and 31, 32 (Figure 10) and a cardan shaft 33. In order to permit transmission of the rotation of the drive shafts 34 in spite of the axial oscillations of the toolholders sliding spline shaft joints 35 are provided. The drive shafts 34 of the generating worms are rigidly interconnected by a gearing 36 and a connecting shaft 37. An adjustable clutch 3% permits the adjustment of the Worms for obtaining a correct meshing of the teeth with the work-piece (phase adjustment).

Moreover, the generating worms 1 of both tool holders are connected through bevel gearing 39, a shaft 40, bevel gearing 41, a differential drive 42, a shaft 43 and bevel gearing ts to a regulating drive 45 which insures through an auxiliary motor 46 a uniform rotaton of the tools.

For executing a generating movement between the generating worms 1 and the workpiece A, i.e. for maintaining a rigid ratio of rotation between these two in accordance with the desired number of teeth on the workpiece, a further driving train is provided through a shaft 47, a pickoif gear group 48, a splined shaft 49 and a dividing gearing 50 in the headstock 11.

In order to produce a constant feed of the workpiece A in direction of its longtudinal axis relatively to the tools a feed step gearing 51 driven by the splined shaft 49 is provided which is connected for rotation with a 7 feed nut 55 through a hollow shaft 52, a clutch 53 and a gearing 54. By rotating the feed nut a threaded, hollow spindle 56 supported bythe headstock 11 is displaced in direction of the axis B of the workpiece A.

For generating helical gears an additional rotation of the workpiece A with'regard to the generating worms 1 in a ratio corresponding-to the feed is required. This additional rotation is obtained through a shaft 57, pickoff gears 58, and a sahf-t 59 with a worm gear 59a on the end thereof which energizes with the input gear of a differential gearing 42. When a straight gear tooth is being formed, alternating drive 58 is not operated and the worm shaft 59 and therefor the bevel gear in the differential which is meshed with the worm wheel 59a are inoperative. The shaft 40, through bevel gear 41, drives the differential gears 42 and thereby the shaft 43 at half of the speed of the shaft 40. The shaft 43 rotates the workpiece A.

In order to introduce into the drive of the workpiece the necessary additional rotation for the generating of helical gear systems, the alternating drive 58 is brought into operation and thereby the shaft 43 has a motion superimposed on its rotation by the worm wheel 59a and the planet pinions of the difierential 42. Depending on the direction of rotation of the gear wheel being generated, this said additional rotation is positive or negative. The alternating drive 58 is formed as a reversing drive which maintains or reverses the direction of rotation of the shaft 59 with regard to that of the shaft 57.

For rapid adjustments in the direction of the feed there is provided an auxiliary motor 60 driving the shaft 57 directly through a chain drive 61.

FIGURES l0 and 11 illustrate a toolholder by means of which an additional, axial reciprocating movement may be imparted to the generating worm. Together with a corresponding oscillating rotary motion of the workpiece this additional reciprocation compensates for possible deviations from the desired direction of the teeth.

The compensating axial reciprocating movement of the generatingworm is generated by a piston 63 which acts on a pinion 64 to move two identical wedges 65 (tapered in longitudinal direction) in the slide guide of the support 28. 1

A further embodiment for obtaining the additional axial, reciprocating motion of the generating worms is shown in FIGURE 12 according to which a piston produces the desired reciprocating movement of the worm through a lever 71 and two wedges 65 which slide in the slide guide of the support 28.

As a result of this reciprocating movement an oscillating rotary motion must be superposed on the constant rotary motion of the workpiece. The motor 16 produces both movements through a cam drive 75 (FIGURE 13) mounted in the housing 17 and being rotatably adjustable with regard to the cam drive driving the tool holders 3. The cam drive 75 drives a piston 76 which acts on fluid in a conduit 77 to move the piston 63, and the cam drive 75 also drives an adjustable lever transmission acting on a piston 78 imparting an axial reciprocating motion to a partial worm 72 in the gearing 50 so that the workpiece receives a reciprocating motion through a worm gear 73. The oscillation angle may be set by adjusting the lever transmission 79 according to the diameter of the workpiece.

The feed of the mentioned hydraulic members is carried out through feed conduits 80 and valves 81. 82 designates safety valves. The pressure medium connections 83, 84 admit pressure fluid to the opposite ends of the respective cylinders to cause the return movements of worm 72 and of the pistons 63 and 70.

The drive of the oscillating movement C is so synchronized with the reciprocating motion of the generating tools that they execute a go movement for each alternate movement C of the tools and a return movement during the intermediate movements C.

Generally speaking when working with the machine of the invention, the outer part of a cylindrical workpiece A of cold worked metal is repeatedly exposed to the action of the generating worms 1, which execute rapid movements C (FIGURE 1) in directions substantially parallel to the axis B of the workpiece A in order to produce the desired profile on the workpiece, this profile being formed by the generating or rollingmotion between the rotating workpiece A and the worm 1.

As the clamping device carrying the workpiece A is slidable on the machine bed in the direction of the profile to be produced, profile lengths corresponding approximately to the stroke of the headstock 11 may be produced. Thus, it is possible toproduce long profiled bodies which may then be cut up into separate sections.

In order to produce a spur gear by means of the machine according to FIGURE 8 the procedure is as follows:

A cylindrical bar, e.g. a steel rod serves as workpiece A' whose outer diameter corresponds approximately to the pitch circle of the gear to be produced. This workpiece is clamped in the clamping device 12, then the generating worms 1 are set in the proper position radially of the rod by means of the manual adjustment 25 so that the distance between the tooth crest of the tool at the inner end of the stroke thereof in the sense of the axis Y, corresponding to the position of these worms shown in FIGURE 8 and the workpiece axis B corresponds to the root circle of the gear to be produced. Moreover, the pitch angle of the generating worms is set by means of the slide support 28. For obtaining the desired number of teeth on the workpiece the necessary pick-off gears 48 are mounted and for the desired pitch angle of the toothing the necessary pick-off gears 58 are mounted. Thereupon the motors 16 and 46 are switched on in order to move the tools so that they execute the movements C in the plane parallel to the profile to be produced. At the same time the workpiece is fed by the engagement of the clutch 53 for the feed gearing 51 towards the Working area between the tools and is rotated about its axis B. This rotation is transmitted to the shafts 5 and therefore to the generating worms by means of the described gearing. As soon as the front end surface of the workpiece enters the range of the operating tools, these form during each oscillation a depression in the workpiece. These depressions are distributed over the whole circumference of the workpiece due to its rotation and the desired profiles are produced by the feed of the workpiece. The material displaced by the formation of the grooves forms the crests of the teeth projecting beyond the pitch circle. By this rotary oscillating and feeding movements all tools take part in producing all tooth surfaces, thus insuring an absolute uniformity of the workpieces.

For producing helical spur gears the longitudinal axes of the generating worms 1 are pivoted with regard to the axis B of rotation of the workpiece A so that the helix lines in the tangential section on the working side of the worms 1 are aligned with the desired helix angle of the gear. The ratio of rotation between the worms 1 and the workpiece A which is a whole number multiple remains the same depending on the desired number of teeth; but the number of rotations of the work must be corrected according to the pitch angle and the feed just as with nor mal profiling machines.

When producing some specific teeth types it has been found that the rolling movements of the profiling worms 1 may produce deviation in the work A from the desired direction of the teeth.

This is avoided by an additional, axial reciprocating movement of the generating worms produced by the alternative embodiment according to FIGURES l1 and 12 together with the additional oscillating rotation of the workpiece about its axis B synchronized with the above movement.

This additional reciprocating movement of the tools takes place in a direction perpendicular to the desired direction of the teeth, i.e. perpendicular to the plane of the movement C (FIGURE 8). It is so set that the tool executes a go movement perpendicular to the plane of the movement C during alternate movements C, whereas the return movement takes place during the intermediate movements C.

Wherever the direction of the teeth deviates these axial strikes of the tools are so adjusted that they start before or after the .tool has hit the work, i.e. before or after commencement of rolling; thus the tools-act longer on one flank of the gear than on the opposite one for compensating the deviation.

The additional, oscillating rotation of the workpiece corresponds exactly to the axial strokes of the generating worms in the generating circle of the toothing to be produced.

The machine described permits the manufacture of rolled profiles in the outer zone of a workpiece and it is possible to produce from generating worms with a basic rack form any number of teeth together with the socalled profile corrections (profile displacement). There.- fore, it is no longer necessary, as with the prior art machines, to provide a special tool for each number of teeth or each type of tooth.

Another advantage of the described machine lies in the fact that no radial forces are taken up by the workpiece supports on account of the opposite disposition of the tools.

Of course, the machine could also be constructed so that the workpiece is maintained stationary and the feed is imparted to the generating tools in the direction of the profile.

Of course more than two tools may be disposed concentrically to the workpiece axis, whereby the pivoting axis of the tools intersect the workpiece axis in one point.

Consequently, while we have shown and described what are now thought to be the preferred forms of the invention, it is to be understood that the same is susceptible of other forms and expressions. Consequently, we do not limit ourselves to the precise structures shown and described hereinabove, except as hereinafter claimed.

We claim:

1. A machine for cold form generating of profiles on cylindrical workpieces, said profiles having raised and depressed portions progressing along the length of said cylindrical workpiece, by moving cold forming tools relative to the workpiece, said machine comprising a plurality of cold forming tools spaced around the circumference of a workpiece to be shaped, a plurality of tool holders in which said tools are mounted, said tool holders being rotatable around axes which are perpendicular to and intersect in the longitudinal axis of said workpiece, each of said tools being rotatably mounted in the respective tool holder for rotation around an axis which is perpendicular to the axis of rotation of said tool holder, each of said tool holders being mounted formovement toward and away from the workpiece along the axis of rotation of the tool holder and along an axis perpendicular to the axis of rotation of the tool holder, clamping means for clamping the workpiece, a first driving means for moving the clamping means and the tool holders relative to each other rotatably and in the axial direction of said workpiece for feeding the workpiece relative to said tools, said driving means being connected to said tools for rotating said tools, and a second driving means connected to said tool holders for moving said tool holders toward and away from said workpiece along the axes of rotation of said tool holders and simultaneously in a direction perpendicular to the axes of rotation of said tool holders in timed relationship to said first driving means, whereby the movement of coordinated.

2. A machine as claimed in claim 1, in which the tools are worms and said second driving means imparting to the tool holder a motion toward and away from the workpiece which is smaller than the desired profile depth, and in which said first driving means rotates said worms about their own axis at a speed which has a predetermined ratio to the speed of rotation of the workpiece.

3. A machine as claimed in claim 2, in which the tool holders are arranged in pairs on diametrically opposite sides of the workpiece axis, and said second driving means oscillates them in opposite directions.

work and the movement of the tools is 4. A machine as claimed in claim '1, wherein the generating tools are worms, and saidseconcl driving means drives said tool holders toward and away from the workpiece and along said workpiece in an elliptical path in a direction opposite to the directon in which said first driving means rotates said worms, and means are connected between said driving means for synchronizing the movements of the workpiece and of the tools.

5. A machine as claimed in claim 4, in which said second driving means comprises means for imparting to the worms an additional reciprocating movement perpendicular to the plane in which said elliptical path lies, and said first driving means include means for superposing an References Cited in thelfile of this patent i UNITED STATES PATENTS Stiefel Mar. 29, 192i Grob et a1. Aug. 23, 1955 FOREIGN PATENTS 7 Switzerland May 14, 195 Great Britain May 7, 1958 Germany Aug. 23, 1956

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