DE2445113A1 - SPRING COUPLING AND METHOD OF MANUFACTURING IT - Google Patents

Description

Serrated coupling and process for its manufacture

The invention relates to a special type of serrated coupling in which the teeth of one coupling half Drum-shaped, that is to say convex in the longitudinal direction on both engagement flanks, while the teeth of the other Coupling halves have the shape of an hourglass, that is, they are concave on both engagement flanks in the longitudinal direction (DT-PS 869.450). Sometimes one or both of the coupling halves have a cylindrical web surrounding its ring of coupling teeth, which is used during machining of the coupling teeth stands in the way of the tools and is notched by the tools in the known manufacturing process.

The invention is based on the object of designing the coupling and the machining process for its production in such a way that that this notching of the web is omitted. The invention thus relates to an improved modification of the known coupling with the aim of making them easier to manufacture and use in some coupling halves, such as in turbine blade rings,

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which are provided with such cylindrical webs and in which the disadvantages described have so far occurred.

The known serrated coupling described above is for years in great extent in use, especially in the manufacture of gas turbines for the aerospace industry, where the blade rings of the turbocompressor and the turbine are formed by separate rotor disks, which are secured by the serrated clutches are rigidly connected. Deliver in this application the serrated clutches provide a very precise centering and drive connection of the blade rings. The manufacturing process is proportionate fast. Because at the same time, two tooth flanks and the corresponding tooth gap bottoms are created on each serrated tooth coupling machined and the associated head edges beveled. Usually this is done with a cup-shaped grinding wheel. Recently The same serrated clutches are extensive in component devices of machine tools, and also in large stationary gas turbines and is used in other cases. The couplings are manufactured using the same known process, however, using a face cutter head, the cutters of which are suitable for size and shape, the same surfaces of rotation to work out how the circumference of the grinding wheel. Therefore, when the term "cutting edges" is used below, it is referred to Term applies in the same way to the cutting profile of a cutter head or that of a grinding wheel.

In the known method, as described in the cited patent is explained, are at the same time two spaced apart tooth flanks, the rounding or beveling of their Tip edges, the profile rounding of these tooth flanks on the tooth gap base and at least half of the tooth gap base itself is machined on each tooth flank «Most of the time, the upper end faces run of the teeth and the base surfaces of the tooth gaps parallel. They are more or less flat and represent surfaces of rotation of the coupling halves, although in some cases inclined cutting tools come to use to work out longer teeth, the rounding between the tooth gap base and the tooth flanks

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have, wherein the tooth gap base surfaces have the shape of two flat, somewhat conical surfaces of revolution. Most of them common manufacturing process extends the tool axis essentially parallel to the axis of the workpiece, and the tooth flanks represent conical surfaces of revolution, their straight Surface lines are inclined to the axis of the workpiece and with conical surface lines of the grinding surface or that of the straight cutting edges the surface described coincide with the cutter head, these surface lines in an axial plane of the cutting tool lie. The conical surface lines of the tooth flanks are therefore to the tool axis inclined at an angle that corresponds to the normal tooth pressure angle.

When using the known method explained above and the known configuration of the serrated coupling, the result is the object underlying the present invention, if the to be worked out The clutch ring gear is on a machine part, which has a projection that is made of one piece with it and protrudes into the area of action of the tool. Such a A projection can, for example, surround the ring of the clutch teeth be a cylindrical web which protrudes in the axial direction from the disk carrying the turbine blade ring and over protrudes the plane in which the tooth gap bottoms lie. Unless this web has such a large diameter that it is extends with clearance around the entire range of motion of the tool, then the tool cuts when working out the clutch teeth Notches into the web or otherwise mutilates it.

For those cases in which such a protruding web is only provided on one coupling half in one piece with it, a solution to this problem has been proposed. In doing so, the tool that works the clutch teeth is opposite to the workpiece aligned in such a way that when the workpiece is partially switched, the tool is in successive axial workpiece planes is tilted in such a direction that it cuts deeper into the serration gaps at the inner end than at the outer end

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the serrations. As a result, the knife tips of the tool wander on a circle that is at a distance from the projecting ridge of the workpiece. Such a tilting of the But the cutter head requires that when machining the other coupling half of the cutter head by about the same amount in the opposite direction is tilted relative to the workpiece. But that means tilting in one direction, consequently on the inner end of the tooth is cut deeper than the outer end of the tooth. This tilting is required to be accurate or approximate To generate matching tooth flanks on the coupling halves when the tooth flanks come into contact with one another are conical surfaces of revolution. When using this known Solution, therefore, the other coupling half must be designed differently from the first coupling half. With her not only must the protruding cylindrical web is missing; it must also be the outer surface of the area to be toothed to under the tooth root of the Clutch teeth may be undercut because the knife tips are on wander in a circle that penetrates deeper into the workpiece in this area. The design of this coupling half is therefore often made considerably more difficult or completely unacceptable, because there are limits to the design of the coupling part.

If it proves necessary when designing both coupling halves, Providing projections, such as sealing rings or cylindrical webs, has therefore hitherto not been a solution to the problem. Wanted to you can use the simple manufacturing process, in which the serration by cutter heads with straight cutting edges or is worked out by straight profiled grinding wheels and therefore receives tooth flanks that are essentially conical surfaces are, then one had to accept the notching or mutilation of the annular protruding web. With a well-known Solution to the problem of the invention has recently been proposed that cut into the cylindrical webs by the tools To cover notches with a special sealing ring.

The solution according to the invention to the problem described above is briefly explained below:

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The invention represents an improvement of the serrated coupling explained above and its manufacturing method and includes a new design of this spline coupling. In this, the basic idea is retained, the clutch teeth in the longitudinal direction on both adjacent tooth flanks to be convex in one coupling half and concave in the other coupling half. Each newly designed in this way The coupling half can still be worked out by a rotating face cutter head that rotates around its axis and thereby traverses the surface of the workpiece in such a way that the tool is at two separate points in the zone to be toothed Workpiece comes to the cut and parts of the opposite to each other oriented flanks of two clutch teeth located at a distance from one another machined, whereupon the partial circuit by a relative The tool and workpiece are rotated around the workpiece axis. The tool axis always comes one after the other in consecutive Axial planes of the workpiece to lie. This machining method of the coupling teeth creates two Coupling halves, each of which has coupling teeth, their flanks are both curved lengthways or lengthwise from end to end with the centers of curvature of the lengthways curvature of the two opposite flanks of each coupling tooth on each coupling half on opposite sides of the tooth come to rest. These properties are characteristic of the method and of the couplings according to the invention are derived from the known method and the known coupling.

A fundamentally important feature of the invention is the use of cutting tools that are used when machining First, work out curved, profiled surfaces of revolution in an axial plane of the tool in both coupling halves, instead of straight profiled surfaces of revolution, and secondly to the axis of the workpiece are inclined, the direction of the tool inclination for the machining of each coupling half is chosen so that in the Workpiece is pierced deeper at the inner end instead of the outer end. The two coupling halves each have both in the

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Direction of the tooth height as well as, as mentioned above, in the longitudinal direction a curvature, and the tooth gap bottoms are concave in the longitudinal direction »

In the simplest embodiment of the manufacturing process According to the invention, spherically profiled cutter heads are used, one of which has a convex cutting surface and the other has a concave cutting surface, both of which have the same spherical radius. Tooth flanks are generated that completely fit together. Regarding the radii of curvature are Deviations possible, e.g. deviations from the exact spherical shape of the cutting surfaces of the tools in order to achieve that the to rest against each other specific coupling tooth flanks in the direction the tooth height or curved differently in the longitudinal direction are.

As is known, it is with the known serrated clutches conical tooth flanks (which are straight profiled in every axial plane of the tool) can only be used to generate ejjpp lungs tooth flanks which fit together completely or have different curvatures in a precisely manageable manner when indented Position of the two coupling halves the corresponding tool axes either coincide or around the coupling axis in are rotatable in a parallel relationship to each other. The two coupling halves have cylindrical projections that are made in one piece with consist of them, or differently shaped projections, then results in the required tilted position of the tool when attempting the To work out the usual conical surfaces, into conical surface lines that cross each other with considerable tooth flank interference. The invention avoids such interference by using spherical or approximately spherical cutter heads that have such Tilting the cutter heads allow them to pierce as deeply as possible into both coupling halves at the inner end of the tooth gap is required to abut the projections of the coupling halves to avoid, but nevertheless to generate tooth flanks lying on top of one another, which are either completely adjacent to one another or to each other in a certain precisely controllable way

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lie,

The invention will now be explained in detail with reference to the drawing. In these show:

Fig. 1 shows two turbine blades, which by the serration coupling are combined according to the invention and each have a protruding cylindrical web for sealing, where the two webs touch each other more or less exactly,

2 and 3 are partial longitudinal sections of the two adjacent turbine blade wheels of FIG. 2, the sealing one annular projection and the coupling teeth are shown, whose tooth gap bottoms are inclined and which therefore allow the tool to remain at a distance from the projections. The tools are shown in phantom, and the two paddle wheels are axially apart for the sake of clarity reproduced separately,

FIGS. 4 and 5 in a manner corresponding to FIGS. 1 and 3 Way, the well-known serrated coupling, in which the outer annular, sealing-off projections are notched,

6 shows a schematic partial section of the coupling, the sectional plane being approximately through the middle of the height of the coupling teeth runs perpendicular to the axis of rotation of the paddle wheel and wherein the coupling teeth have a convex longitudinal curvature and the Coupling teeth within the tool circle in a partial switching position are shown and a segment of the annular projection is shown,

7 shows the view of a plane which runs at right angles to the line OP in FIG. 6 and the two adjacent one another Coupling teeth are partially shown,

Fig. 8, the two cutter heads in an axial plane of the clutch, which the line OC contains the Figure 6 and also record the ge * tended cutter head axes of the invention, that is where there is an axial plane, the de »workpiece and the two cutter heads together is,

FIG. 9 shows an axial plane of the coupling which contains the line ÖP of FIG. 6 and shows the outlines of the tooth profiles which are rotated into the plane of the drawing.

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In Figures 1, 2 and 3, two serrated clutches 2 and 4 are illustrated, which are designed according to the invention. Every Coupling half consists of one piece with a turbine blade wheel 6 and 8. The paddle wheels and the couplings are designed symmetrically to their axis 10. Every turbine blade wheel has an annular projection 12, 14, which the clutch teeth the receiving space surrounds and seals. The end faces 16 and the projections 12 and 14 coincide more or less precisely with the Partial circular plane 20 of the clutch ring gears together. This plane is the common plane of rotation used in the illustrated Embodiments should get to the point that represents the mean tooth height of the clutch teeth. The dashed The cutter heads 22, 24 shown have externally and internally cutting knives which have spherical or approximately spherical surfaces of revolution describe. These surfaces have essentially the same dimensioned radii of curvature 26 and 28. The inside for the cut coming knives in Figure 2 and the knives coming outside to cut in Figure 3 can be curved or straight, as desired, as they only serve as a roughing knife.

As can be seen, each cutter head axis 30, 32 is inclined to the axis of the associated workpiece in workpiece axial planes, each in such a direction that the cutter head penetrates deeper at the inner end of the tooth gap than at the outer tooth gap end. The inclination of each knife head axis is sufficient for the knife tips to move past the points P " _D at a distance from the end faces 16 and 18 of the annular projections. On these

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Places roughly intersect the ring of the knife tips and the inner circle of the end faces of the projections. You can determine the inclination required for this very easily from the draft, after one has the basic proportions of Has temporarily set clutch and cutter head according to the known construction. The slope estimated first becomes then checked to ensure that once the design has been completed in the manner outlined below, the required Space between the cutter heads and the end faces 16, 18 remains.

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If you use curved cutting profiles of the cutter heads or grinding wheels when manufacturing the serrated coupling described here, then the degree of inclination between the tool and the workpiece is not necessarily required for one of the coupling halves to be just as large as the other half of the coupling, as long as the pressure angles are matched accordingly. This is an additional feature of the novel process that can be of particular value in some cases where the projections to be provided by the tools on the two coupling halves are not designed to match.

FIG. 4 shows two serrated clutches 34, 36 which serve the same purpose as those shown in FIG. Figure 5 corresponds FIG. 3 and shows a coupling half and the tool used for its production in the known method which was explained at the beginning became. As is the case with the adjacent turbine blades 6, 8 of Figure 1, the paddle wheels 38 and 40 of Figures 4 and 5 are provided with annular projections 42, 44, which consist of one piece with the paddle wheels and project up to the partial plane 46 of the coupling, so that their end faces coincide with this sub-level. The tooth root surfaces of each coupling half lie in a flat surface of revolution, and this This also applies to the knife tips of the knife heads if they have pierced the workpiece to the full depth of the tooth gap. There the tools have diameters which largely correspond to those shown in FIGS discussed above and shown in U.S. Patent 3,356,339) that notches 47,49 are cut in the projections 42,44.

Figures 6 to 9 represent design drawings from which details of the geometric principles of the new method result in aligning the cutter heads that cut spherical surfaces for both coupling halves. You can also see the characteristics of the new toothing of the two coupling halves.

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FIG. 6 shows a partial section of the serrated tooth coupling in a plane of rotation which runs through the center of the tooth height. This plane can be called the parting plane. When looking at FIG. 6, one looks in the direction of that coupling half, the teeth of which have curved tooth flanks, which are finished by the internal cutting knives. The points P and P ¹ lie on the middle pitch circle. Point C represents the axis of a cutter head which is intended for a coupling half corresponding to the state of the art. The line r or PC represents the radius of such a cutter head in the dividing plane. The circular arc c represents the curve in the dividing plane that would be generated by such a cutter head. Line A or OP is the mean pitch circle radius of the coupling. The lines OP and PC are perpendicular to each other. What is shown in FIG. 6 provides the basis for the subject matter of the invention, which will now be explained with reference to FIGS. 7 to 9. With the new type of serrated tooth coupling, the tooth flanks from the inside to the outside are strictly speaking not circular, but rather weakly elliptically curved, and the ellipses go through the points P and P. The section 50 represents part of the circular projection, the end face of which lies more or less precisely in the dividing plane, at least in the exemplary embodiment described. The point Ρ ~ _ρ on the projection represents approximately the point at which the cutter head would notch the face of the circular projection if the cutter head were not inclined.

The view shown in FIG. 7 lies in a plane which intersects the teeth perpendicular to the tooth flanks and which runs through the point P. In Figure 7, parts of the serrated teeth of the coupling half W and the coupling half ¥ _ are shown. reproduced ₀ The tooth flanks of the coupling half ¥ are convexly curved from the inside to the outside and the tooth flanks of the coupling half W are concave. The line PC in Figure 7 represents the parting plane, and the angle 0 is the normal pressure angle at the point P. The line X shows the axis of an imaginary cutter head, which corresponds to the prior art, while the line r _¥ or

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PCLj represents the true length of the normal radius of curvature of the tooth flanks according to the invention, which are to be regarded as parts which are contained in the tooth heights of the circular arc c. The point C _n lies on the cutter head axis X _Q , which is represented in FIG. 6 by the point C, this cutter head corresponding to a part which is designed in the usual and known manner. The line X. in FIG. 7 shows the axis of the spherical cutter head, which according to the invention is intended for the coupling half with the convexly curved tooth flanks, and the point Χ ^ _ρ represents the intersection of this cutter head axis with the dividing plane. The axis X goes through through the point C ^. Their position results directly from FIG. 8. The partial sizes b and b of the tooth height

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lie in the plane of Figure 7 and represent the tooth root of the two Coupling halves with the convex and concave tooth flanks on the coupling radius A, see Figure 6. They are in the illustrated preferred embodiment dimensioned the same.

FIG. 8 is a view of that axial plane of the coupling which contains the line OC of FIG. Illustrated are X,

the axis of the coupling and the projection of the point P on the line ÖC, which in turn reproduces the partial plane in this representation. The partial sizes b and b are measured perpendicular to the dividing plane from point P and end at points 5 ^ »and 52, respectively. For _{the sake of simplicity, point P_ p} is shown on line OC, known to coincide with the sub-plane. The radius of curvature r ^ is shown starting from the center C _{n of} the circular arc. Furthermore, the cutting edges of the two cutter heads T. and T ″ are shown. The cutting edge lengths E ^ and E ₂ slightly exceed half the tooth gap width at the narrowest points. The setting of their angle of inclination results from a calculation in such a way that flat tooth gap bottoms result over the entire tooth gap width or a roof-shaped shape of the tooth gap bottom in the width direction. The smallest amount of inclination of the cutter head axis which is necessary so that the cutter heads T 1 or T "spare the annular projections 50, from lines passing through the points 52 and 5" and the point P "" on the

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go through opposite sides of the parting plane. Because of the location of the end faces of the annular projections in this Embodiment, the angle of inclination i ^. and ig of tools be dimensioned the same or approximately the same. Of course, it is not necessary for these angles to be the same as long as as the radius of curvature r "is maintained when a full The tooth flanks of the coupling teeth lie against one another in the longitudinal direction is desired and the centers of curvature coincide at both cutter heads at C ". The knife angles of the knife heads at the center point P depend on the chosen angles of inclination.

If it is desired that the tooth flank curvatures of the two coupling halves deviate from one another, then that can be done basically achieve in the same way as with the previously known serrated clutches of this special type with conical tooth flanks. Anyone who understands the design disclosed here with tooth flanks lying closely on top of one another does not need any further instructions.

For example, the cutter head with convex tooth flanks can be cut with a tool that machines a smaller spherical surface in order to achieve deviations in the curvatures of approximately the same number for the tooth profile and the tooth length. In the process, the cutter head moves around a smaller number of teeth in the machining area, as shown in dashed lines in FIG. In FIG. 6, a new line of symmetry OC 'can be seen in the processing zone, an intersection curve running ^{through P and P M.} In FIG. 7, the new center of curvature C 'lies in the plane of the drawing on the original tooth flank normal.

PC ' _N represents the new spherical curvature radius for the convex tooth curve. The axis of the new cutting tool for cutting the coupling half with the convex tooth flanks, which are adapted to the tooth flanks of the other coupling half with limited contact, passes through point C' _N and lies in the plane which is perpendicular to the plane of the drawing in FIG. 6 and contains the line OC ·. The whole construction of FIG. 6 is swiveled around

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an angle '. * around the point O, then the line ÖC' _N comes to coincide with the original position of the line ÖC. Here, too, the inclination of the axis X _{1 of} the new cutter head, which is necessary in order to spare the annular projection 50, can be determined by taking the points C ' _N1 , P ₁ , P ¹ Qp ₁ from FIG. 6 in the figure 8 is projected and the circular arc described by the figure 7 ^{around the center point C 1} VT ₁ with the radius of curvature PC ' _{N is projected.}

How much the profiles of the adjacent flanks of the coupling teeth differ from one another can be determined independently of the Determine the deviation of the longitudinal curvatures by taking the relative Centers of the tooth flank curvature in the tooth height relocated to points that are selected at the necessary distance from point P. are. Of course, these center points do not have to sit on the knife head axes. For example, in the most extreme cases, the Center of curvature of the profile extending in the vertical direction of the tooth for the cutter head, which forms the concave tooth flank machined, lie at a certain distance from point P, the tooth flank running essentially straight in the height direction and therefore allows the use of straight cutting edges of the tool for machining this coupling half.

FIG. 9 shows a view of an axial plane of the coupling which contains the line OP of FIG. 6 and the outlines of the Shows tooth profiles rotated into the image plane. The head surface of each coupling half can be used as a flat surface of revolution be trained. This applies to one or both coupling halves. The head surface can also be a cone surface, which is generally runs parallel to both tooth root angles and goes through the middle points. These angles are calculated as follows:

tg e ~ = ^sin

1 - tg Ji cos & tg ι

where \ = tg "A

i = angle of inclination of the cutter head to the workpiece axis 0 = normal pressure angle in the dividing plane at the middle point P.

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- Ik -

The curves R ^, R ₂ at the base of the tooth gap can easily be determined.

The corners of the tooth tips can be bevelled slightly. The inclined surfaces form surfaces of revolution that are used when machining the corresponding tooth flank surfaces are produced at the same time. This is done by appropriate design of the cutter head or by dressing the grinding wheels in a known manner, This is common practice in the manufacture of the known serrated clutches on which the invention is based.

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Claims (7)

Expectations Tj serrated coupling in which the planks on both sides each Coupling halves are curved longitudinally from one end to the other and the centers of curvature of the longitudinal curvature of the opposite Flanks of each tooth on each coupling half on opposite sides Sides of the tooth lie, each tooth flank is also curved in the direction of the tooth height, characterized in that the tooth gap bottoms of each coupling half (2, 4t) in the longitudinal direction are concave and that the tooth gaps of each coupling half (2, 4) are dimensioned deeper at the inner end than at the outer end. 2. Serrated tooth coupling according to claim 1, characterized in that the abutting tooth flanks lie close to one another Are spherical surfaces. 3. Serrated tooth coupling according to claim 1, characterized in that the abutting tooth flanks differ somewhat from one another Have radii of curvature. 4. Serrated coupling according to claim 1, wherein the teeth of the a coupling half is designed straight in the direction of the tooth height. 5. A method for toothing the serrated coupling according to any one of claims 1 to 4, in which a) the interlocking of the workpiece by a rotating tool takes place in the manner of a face cutter head, which acts on the surface of the workpiece by cutting such that the cutting path of the Tool in the zone of the workpiece to be toothed on two separate Places acts and thereby the oppositely directed flanks of two spaced apart teeth of the working out the desired toothing, b) then a partial circuit by relative rotation of the tool and workpiece takes place around the workpiece axis and c) the machining operations and the partial circuits , alternate, with the tool axis in successive axial Planes of the workpiece come to rest until all of the teeth are carved out are characterized in that the machining 509832/0653 work 1) the axis (30 - X ₀ , 32 - X ₄ ) of the tool (22 - T, £ X "θ 2k - T.) relative to the axis (lü) of the workpiece (6, 8) (in the axial planes of the workpiece) is inclined in one direction (ij, ip) ^d * ^{e for each} coupling half is chosen so that at the inner end the tooth gap is inserted deeper into the workpiece than at the outer end and 2) when interlocking at least one of the two coupling halves a tool with curved cutting edges is used. 6. The method according to claim 1, characterized in that during the machining, the tools (24 - T.) work out convex spherical surfaces when interlocking a coupling half, while the tools (22 - T ₂ ) work out concave spherical surfaces when interlocking the other coupling half fit snugly against the convex spherical surfaces. 7. The method according to claim 6, characterized in that for interlocking one of the coupling halves, a tool with a straight line Cutting edges is used and works out surfaces that have a substantially infinite radius of curvature in the direction of the tooth height to have. 509832/0653