DE1955385A1 - Method and device for the production of undercut circular arc grooves - Google Patents

Description

S chw.

Brovm, Boveri & Gie joint-stock company. Baden (Switzerland)

Method and device for producing undercut circular arc grooves.

The invention relates to a method for the production of approximately in the direction of the generatrix of a rotating body, Circular arc grooves provided with undercuts, in particular blade fastening grooves on rotors of turbo machines, by means of a tool spindle head, the drive shaft of which is normal to the end of the four-piece piece, and with a cutting tool rotating around the axis of the drive shaft for the machining of the two groove flanks of a pre-machined groove, and a device for implementation of the procedure.

It is known per se to produce profile grooves that follow an arc of a circle by milling. A pinger milling cutter arranged in a tool spindle head is swiveled into a radius so that its feed movement describes an arc and the teeth of the end milling cutter machine a flank of the groove. During the pivoting movement ULm in the opposite direction, the teeth on the other flanks of the groove lift off chips. Long work tents are necessary for the grooving because of the Arbeltsmethode, since the finger cutters only advance with a small feed rate and a shallow depth of cut

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In addition, occur in this manufacturing process to the Pinger milling cutters often suffer damage due to the one-sided loading of the shank, if in relation to the groove width large undercuts are to be made. Therefore For example, when making fir tree grooves, it is necessary to close the two flanks in two passes edit .. Because of the required surface size and the close machining tolerances, a third? - tool pass is sometimes required necessary.

When making such curved grooves with Backstitching, the methods of simple measuring or fitting cannot be used, but it becomes necessary to to carry out comparative measurements with the help of gauges or calibres. However, this results in great difficulties which are based on the often uneven machining of the groove flanks. Above all, when machining the groove flanks with the risk of professional shifts expected,

The present invention is based on the object of the long machining times for the production of circular arc grooves and avoid undercuts and eliminate the tedious yet imprecise methods of measurement.

The object according to the invention is thereby achieved achieved that inelnande ^ 'arranged working groups of the two-part Cutting tool the two groove flanks with the same

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Brush early chip removal in the groove area and the normal distance between the circumferential lines of the working groups by shifting the associated axes of rotation against one another is changeable.

A further process step according to the invention is to be seen in the fact that the working groups of the two-part Cutting tool are pivotable about a fixed axis of rotation lying outside the working circles.

. According to the invention, an advantageous method step is that the working groups of the two-part cutting tool Swivel from a non-coaxial to a coaxial position during the chip removal.

An apparatus for performing the method according to the invention is characterized in that two of the drive shaft driven, rotating cutter heads in two mutually displaceable cutter heads supported on a base plate Bearing elements are arranged, and that the cutter heads from rings with tooth roots and with several cutting parts are formed, and the cutting edges of the cutting parts at the same time each edit a groove flank whose curvature is that of the corresponds to the closed cutter head.

A preferred embodiment of the invention The device is designed in such a way that each of the bearing elements is equipped with an articulated pivot lever ' and the pivot lever through one eye each on a stationary one

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Pins are rotatably mounted, with means for guiding the mutually displaceable bearing elements on the base plate are provided.

A practical training of the device according to the Invention is characterized in that on the base plate means for controlling the feed of the cutter heads from a non-coaxial starting position into a coaxial end division during the chip removal and back to the starting position are provided after the work process has been carried out.

A device for carrying out the method according to the invention is advantageously designed in such a way that that the cutter heads are formed from two rings provided with recesses and lying in parallel planes and that the cutting part feet of the second cutter head the recesses of the first cutter head protrude and that the cutting part feet of the first cutter head into the recesses of the second cutter head reach in, and that the cutting part feet with the recesses during the rotary movement Comb tooth-like, but there is no surface contact.

The invention is to be explained in more detail with reference to the drawing,

Fig. 1 and Fig. 2 show a diagram of the working method of the two cutter heads.

Fig. 5 and ^ show an embodiment of a Werlczeug-ßpindelkopfes at the start of work and at the end of the chip removal.

009887/1219 BADORfGlNAL

Pig. 5 is a vertical section through the ^{suction spindle head shown in B 1} Ig, and 4 along the line AA, but on an enlarged scale.

Fig. 6 illustrates one. Cut through the two from the Cutter heads detached from the tool head according to line B-B.

B'ig. Figure 7 shows a top view of both in Pig. β cut Cutter heads from the side facing the groove during machining.

In FIGS. 1 to 7, corresponding parts are denoted by the same reference numerals.

1 shows a tool 9 symbolized by a thick dash-dotted line, with lines simultaneously identifying the two groove flanks 7 and 7 to be machined. A schematically drawn cutter head 1, mounted in a sliding or rolling manner in a support ring 3, as indicated by cliir-sh 5 &'4> ~ - ^τ ·, is inserted into the pre-machined Ihi'c (7th - 3). The introduction is made major-oh. sins in iiiohi ^ -g. r-'if a ν / & rk G tucker ζ engend & 2ΐ instils tehencL lktl geciir.-iten tool locker Cilko ^ rie *

hencLü l

if Dch-imatiseh ciarf ^ itellt. imd lie- · U s ^ c- ^ ev ^ rssc ^ x ^ · ~ i-- · i.iilb deu first Maßcerkopfcü 1, the ac _: n gj / öcsäip ^ n P ^: - 3 ^ HeH ^ : -. -, - has. The Mosserko /; i "2 wiM sleiohsextiß ml '-: - ά ^ Ά i-Jesssrkopf I by the pulling part movement described above in sio vox ¹ « machined groove, after which the two Moaseri heads during de

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Rotatiorx touch the two flanks 7 and 8 and the chip lift he follows.

In the retracted position shown in Fig. 1 it can be seen that the axes of rotation of the cutter heads 1 and 2 _{marked as M 1} and M _{9 are in a non-coaxial position »}

Pig. FIG. 2 shows a diagram of the work process that corresponds to FIG. The difference between the two figures ™ is given by the displacement of the two working circles of the cutter heads 1 and 2 carried out during the advance. The displacement of the axes of rotation M ₁ and H 2 is ended when the two are in a coaxial position. This fact results in the profile having the final dimensions of the groove flanks 7 * 3 at this point in time.

The two cutter heads 1 and 2 are then moved back into the starting position and extended in the same way as the adjustment movement, but in the opposite direction aiiE the hat of the workpiece 9.

Fig. 3 shows its execution form of a works contractor, as he StB. ? .ri the. Spindle head single .Ιιβ -.- ιΐί'ιη.'Ίϊο'η & η ^ li ^ reclit «Prüsma3ch" / - 'i € 2' ~ .B & E "^;; ^ aeli1; can be. JMo- 'c- ^ Ar ,. '^ ßfftrköpfQ 1,2 werdei. ms in Fig _. 1 and 2 with the help of Lag: ■ /: "■; ^ 6 in the TiT-.sriiigei) 3> ^ rotatable aufgsxiomisan _ä An dl: - both support rings 5 ^ 4 are mutually flexible pivoting levers H ₉ IS articulated, the second end of which has an eye bearing 26.27

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is formed. These eye bearings 26, 27 are rotatably arranged on a bearing journal 10 fastened on the base plate 14, which forms the fulcrum for the two mutually pivotable support rings 5 * 4. To guide the same are on theirs Perimeter lugs 12 are provided which have guide slots. The guide slots take on bolts 25, which also are attached to the base plate 14. This ensures precise guidance of the displacement movement and at the same time is a Means given to prevent the two support rings from a possible lifting from each other, and their contact with the base plate 14 to ensure.

There are more claws on the two support rings 5 * 4 15 and 16 articulated, which are transmitted by a gear motor 18 via cam rollers 17 tfie feed movement to the support rings and thus automatically move the cutter heads 1, 2.

The rotary movement or the torque is controlled by a drive shaft (not shown) with the axis M to which the shown Drive plate 24 is connected, removed. About in the drive plate 24 fastened bolts 25 and Levers 19 and 20 movably arranged thereon, the cutter heads 1 and 2 are set in rotation. The lever 19 is with his the second end is connected directly to the cutter head 2 via the bolt 21. The lever 20, however, is with the corresponding The end is connected to the cutter head 1 via the bolt 21a fastened in an extension 22, the extension 22 to compensate the different radii of the cutter heads.

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Pig. 4 shows the coaxial position of the machining of the rear: Kreisbogennuten cut with the same tool spindle head as shown in Figure 3, the axes of rotation M, and M ₂ coincide this figure with the designated axis M.. This position also means the end position of the feed and the chip removal. The cam rollers IJ, which regulate the feed rate through the increase in the cam tracks and the feed itself through the difference in level of the cam tracks, take over the return of the cutter heads to the starting position after this end position, in which the cutter heads are moved out of the groove.

. Fig. 5 shows a section through the tool spindle head, whereby the cutting plane through the guide bolts attached to the base plate, in this case screwed in is marked.

The mutually displaceable support rings J and 4 are arranged such that the supporting ring 4 is able to slide on the base plate and the support ring 3 ^au i "the support ring 4 is slidable. By further bearing elements JO and by fixing means such as nuts Jl, the supporting rings 5 , 4 clamped to the base plate 14 without inhibiting the sliding movement of the parts against each other. In the first, in this case front support ring 3>, a bearing seat ring 5 is provided for the inside and 5a for the outside they for receiving the sealing means; 52, the

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be installed between the two. In the other support ring 4 an outer bearing seat ring is not necessary, because the kisser Bearing seat is provided in the support ring 4 itself. A bearing seat ring 6 has the inner bearing seat and the sealing means 33 are again between the support ring 4 and the bearing seat ring 6 arranged.

The bearing rings 5 and 6 are mechanically connected with the drive shaft 3 ^> being a drive plate 24 is fastened to this shaft by means of screws 27. By screwed into the drive plate 24 bolts 23 and the bolts 21, on which the rocker arms 19 and 20 are rotatably arranged, the movable connection is made.

Because the two bearing seat rings 5 * 6 are at unequal distances of the drive plate 24, it is necessary to arrange a shoulder 22 on the receiving ring 5 by the bolt is screwed in. The rocker arms 19 and 20 are each provided on the bolts 23 against axial circlips Shift secured.

However, the bearing seat rings 5 and 6 still have one task to take over, which is the actual cutter heads 1 and 2 to be attached to them and to be adjusted or centered. The two cutter heads are only through one in this figure The dash-dotted outline, the springs 35 ensuring the entrainment of each cutter head. The cutter heads can for example be attached to the bearing seat rings 5 and 6 with screws that are thickened on the circumference.

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On the one hand, there is an exchange option for the use given another cutter head and on the other hand, the Peineeinstellung the two cutter heads 1 and 2 to each other in a simple manner.

FIG. 6 shows a section through the cutter heads 1 and 2, three main parts being fundamentally differentiated at the cutter heads. In the case of the cutter head 1, the ring la forms the basic element in which the aforementioned screw through-holes are provided. Furthermore, the tooth root 16 'is placed on the ring la and the tooth part 28 is connected to it in turn. In the case of the cutter head Λ. The parts ring 2a and tooth root 2b are also to be distinguished, only the tooth part 29 has its cutting edges on the outer circumference, while the cutting edges of the tooth part 28 are arranged on the inner circumference.

Another difference between the two cutter heads 1, 2 is given by the fact that the ring la on the inner Has circumference recesses Ic for partial inclusion the tooth roots 2b of the second cutter head 2 are used. In contrast, there are no openings in the ring 2a of the cutter head 2 provided, but the space remaining free between the tooth roots 2b is partially due to the tooth roots Ib filled out.

The movement that the two cutter heads perform could be called the meshing of an internally toothed ring gear with a., externally toothed pinion, where

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However, there is no common contact surface, but between the Schneiciteilfüssen Ib and 2b and the respective Recess Ic and 2c always remains a free space.

On the cutter head 1 strips 37 are also provided, to which a cover plate 36 is attached. Around the tooth base 2b of the cutter head 2 v / earth sealing strips 38 are arranged, which are attached to the tooth root 2b by pressing edges 39. The intended Cover must be movably slidably attached to the cover plate 36 and its size must be as large as possible Adjustment of the two cutter heads correspond to each other. Complete coverage of the two cutter heads 1.2 against the groove is because of the chips that may penetrate into the gap between cutter head 1 and cutter head 2 necessary, as these could be an obstacle for the different rotary movements.

Fig. 7 shows a plan view of part of the two Cutter heads 1, 2, the recesses Ic of the cutter head 1 can be seen better. The one behind in this illustration the aforementioned lying cutter head 2 protrudes through the recesses Ic with its tooth root 2b, while in the through the tooth roots 2b formed gap 2c reach into the tooth roots Ib of the first cutter head 1.

Because the cover is designed to be movable, the strips 37 are only positioned over the inner arch of each tooth root Ib arranged, to which the cover plate 36 e.g.

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Rivets or grooved pins are attached. The elastic sealing strips 58 have a on the inner and outer part of the arch larger width, like the parts running in the radial direction, since those occurring due to the axial displacement Slideways measured in the radial direction are greatest.

It appears two-dimensional, the tooth roots Ib, 2b individually SJi. to arrange the rings la and Ib mountable to the different profile shapes not having to exchange the whole cutter head.

• An advantageous embodiment of the tooth parts is therein to see that cutting tips can be inserted into the tooth parts are, their attachment to the tooth parts 28,29 in conventional This can be done e.g. by screwing or soldering.

Because of the reduced processing time, the advantages of the invention are not only in the economic field, but are also given by the fact that a pre-machined groove is made by a single operation on both flanks 7,8 is brought to the finished size, and that a profile shift is completely excluded due to the simultaneous machining and the measurement methods are largely simplified.

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Claims (1)

Patent claims s © Process for the production of undercuts running approximately in the direction of the generatrix of a rotating body provided circular arc grooves, in particular blade fastening grooves on rotors of turbo machines, by a tool spindle head, whose drive shaft is normal to the workpiece producing, and with one around the axis of the drive shaft rotating cutting tool for machining the two groove flanks of a pre-machined groove, characterized in that that nested / arranged working groups of the two-part cutting tool (1,2) the two groove flanks (7,8) at the same time Coat the chip removal in the groove area (9) and the normal distance between the circumferential lines of the working circles by moving them against each other the associated axes of rotation is variable. 2. The method according to claim 1, characterized in that the working groups of the two-part cutting tool (1,2) by one Fixed axis of rotation outside of the working groups can be pivoted. j5. The method of claim 1, characterized in that the working groups of the two-part cutting tool (1,2) pivot during the Spanabhubes of a non-coaxial (M ^, Mg) in an axial ko (M) position. 4. Device for performing the method according to claim 1, characterized in that two of the drive shaft (34) 009887/1219 driven, rotating cutter heads (1,2) in two mutually displaceable bearing elements supported on a base plate (14) (3 to 6) are arranged, and that the cutter heads (1,2) from rings (la, 2a) with tooth feet (Ib, 2b) and with several cutting parts (2b, 29) are formed, and the cutting edges of the cutting parts (20, 29) each have a groove flank (7, B) at the same time. machine whose curvature corresponds to that of the assigned cutter head (1,2). 5 · Device according to claim 4, characterized in that each of the bearing elements (3 to 6) with an articulated pivot lever (11,12) and the swivel levers (11,12) each by an eye (26,27) on a fixed pin (IC) are rotatably mounted, with means for guiding (13,25,30) the mutually displaceable bearing elements (3 to 6) on the Base plate (l4) are provided. 6. The device according to claim 4, characterized in that on the base plate (14) means (17,10) for controlling the advance of the cutter heads (1,2) from a non-coaxial initial position (M ₁ , M ₂ ) into a coaxial end position ( M) are provided during the chip removal and again in the initial position (M ₁ , M ₂ ) after the work process has been completed. 7. Apparatus according to claim 6, characterized in that the means (17, 18) for controlling the feed are formed from a cam-controlled mechanical-electrical system (15 to 18). 8. Apparatus according to claim 4, characterized by the ■ Κ ** Λθ3 «009ββ7 / 1218 6ad original - 15 - ■ 44/69 Power transmission from the drive shaft (34) to the two Cutter heads (1,2) £ Ι £ 53Ε2 ££ Ξ ^ ££ 2Ι by means of two tenons (21,25) mounted rocker arms (19,20). 9. Apparatus according to claim 4, characterized in that the cutter heads (1,2) are formed from two rings (la, 2a) lying in parallel planes and provided with recesses (Ic, 2c) and that the cutting part pods (2b) of the second cutter head (2) the recesses (ic) of the first cutter head (l) protrude and that the cutting part feet (Ib) of the first Cutter head (1) into the recesses (2c) of the second cutter head (2), and that during the rotary movement the cutting part pods (Ib, 2b) with the recesses (ic, 2c) Comb tooth-like, but there is no surface contact. 10. The device according to claim 4, characterized by the small profile cutting plates which can be inserted into the cutting parts (28, 29). 11. The device according to claim 4, characterized by a movable cover of the cutter heads (1,2) by means of a Plate (3b) and elastic connecting elements (30,39) from the plate (36) to the cutting part pods (Ib, 2b) via strips (37). 12. The device according to claim 4, characterized in that on the bearing elements (3 to 6) claws (15,16) are articulated, which the feed movement of a cam control on the Transfer tool. Public company Brown, Boveri & Cie. 009887 / 1213- _BAB0RlGlNAL