US 2565925 A
Description (OCR text may contain errors)
Aug. 28, 1951 A LOMBARD ETAL 2,555,925
METHOD OF MANUFACTURING GUIDE VANES FOR AXIAL FLOW TURBINES AND COMPRESSORS Filed March 24 1947 3 Sheets-Sheet 1' EI'AL ING GUIDE VANES FOR AXIAL FLO 195.1 A'j'A. LOMBARD METHOD OF MANUFACTUR Filed March 24, 1947 TURBINES AND COMPRESSORS 3 Sheets-Sheet 2 Aug. 28, 1951 3 METHOD OF MAN Filed March 24, 1947 TURBINES AND COMPRESSORS A. A. LOMBARD ETAL UFACTURING GUIDE VANE S FOR AXIAL FLOW 5 Sheets-Sheet '5 &
frwaarr I 050551222, :6? ZomZarJ- 2W2ZZ2'7' Z paged Patented Aug. 28, 1951 UNITED STATES PATENT OFFICE METHOD OF MANUFACTURING GUIDE VANES FOB, AXIAL FLOW TURBINES AND 'COMPRESSORS Adrian Albert Lombard, Clitheroe, and Walter Edward Dazeley, lwiston, near Clitheroa Eng- -land, .assignors to Rolls-Royce Limited, Derby, England, a British company Application March-24, 1947, Seria-I'No.736,806 In GreatBritain April '10, 1946 A 2 Claims. I
This invention relates to the manufacture of guide vanes for axial-flow turbines and compressors. The throat area of the nozzle guide vanes (that is the area between the trailing edge of each vane and the adjacent vane on its concave side) of an internal combustion turbine is a critical area controlling the work output of the turbine and depends not only .on the shape of the vanes but also on the angle at which each vane isset to a radial plane through the turbine axis. The vanes are normally mounted in inner and outer .rings andit is essential, therefore, that themeans on the vanes for locating them in the rings should be correctly located on them.
According to the present invention a repetition method of manufacturing a guide vane comprises the steps of first shaping the vane proper to its final configuration, supporting the vane in a jig which engages the vane proper at points or lines which in the final assembly :of vanes define the theoretical throat area measured between adjacent vanes and machining the locating means on the vane while it is so supported. One such location may be at points or along a line at the trailing edge of the blade and another engagement .is ata point or .line on its "convex face that would be nearest the trailing edge of the next vane when the two vanes are correctly assembled together. It is preferred that the vane should be located by its trailing edge and a single point .on its convex face.
The present inventionis particularly applicable when the vanesare formed 'as precision castings so that the vanes proper require no machining but it is also applicable when the vanes are formed as forgings to the final vane configuration or as forgings or castings and finished by machining. It will be -seen that the present invention ensures that the locating means on the vanes shall be correctly machined with reference to a plane through the two lines that define the theoretical throat between the assembled vanes so that when the vanes are assembled, the cor rect throat area will be obtained. A practical application of this invention will now be described, by way of example, with reference to the accompanying drawings whereof:
Figure l is a side view of a nozzle guide vane which is manufactured in accordance with the present invention.
Figure 2 is a view in the direction of arrow 2 of Figure 1,
Figure 3 is a diagrammatic development viesshowing the relative disposition of the vanes when mounted in position in the turbine,
Figure 4 is an end view of a jig .for locating the vane of Figures I and 2 whilst itv is being machined and :also of a support for the jig,
generally indicated at -lll-anda1pair of tablets H and I2. The vane is of .aerofoil section (Figure 2) and is formed with a straight leading :edge .13 and straight trailing-edge 14. Each tablet H and. I2 is a parallelogram in plan and has its front and rear edges ll, [2a and lib, I21) in linewith one another whilst the front edges are parallel with the rear edges.
The guide vanes .are mounted in the manner described in :the specification to application No. 727,520, the tablets I l and 1.2 being located in inner and outer rings so that part I!) lies generally radially of the ringsand between them. When so mounted, a development view showing the parts I'll of adjacent vanes in section is as in Figure 3.
The throat area of theaguide vanes is determined by the distance a: between the trailing edge I4 .of each vane and the nearest point Hi to the trailing edge on the convex side it of the next adjacent vane. This area decides the work output of the turbine :so that the distance :1,- requires to be accur'ate this, in turn, will be determined by the degree of accuracy with which the tablets I] and 'ilz'sare mounted in the rings referred to. Finally, the :method aof machining the faces-of the tablets which locate them in position in the rings will decide the distance as. This invention is directed to machining the tablets whilst the vanes are located by those parts of it which define the distance ."cand hence the throat area. The parts are the trailing edge [4 and the point l5 at a certain determined position along the length of the vane (Figure 1). H
To efiect the location referred to the vane is mounted for machining in the jig of Figures 4 to 6. Turning to these'figures: the jig comprises a block I! formed with an opening 18 to accommodate the vane with its tablets II and I2 projectlng from the opening. A V-shaped groove I9 is formed at the bottom of opening 13 and trailing edge I 4 of the vane is received in this groove so that the blade is free to pivot about 3 this edge. A pin 20 with a rounded head is mounted part-way up one side of opening 18. The. pin forms an abutment against which the convex face I6 of the vane is held by a screw 2 I. The screw 21 engages the vane by a cap 22 freely rotatable on the screw.
The points of engagement of pin 20 and cap 22 chordwise of the vane are determined by their location above groove l9. To determine their engagement lengthwise of the vane, the block carries at each side a stop 23 which is adjusted to engage the inner faces of the tablets I l and 12 and positively locate the vane lengthwise of the jig. It is arranged that pin 20 engages face [8 at point I5.
The axes of pin 20 and cap 22 are relatively displaced in a manner which causes the edge M to bear against one side of groove 19 when screw 2| is tightened.
A pair of jaws 24 are carried on one side of opening I8 so that they overlie the leading edge 13 of the vane and are adjustable by nuts 25 to engage the edge and clamp the vane against groove l9 within opening I8. The surfaces of the block I! shown in the drawing make the same angles to one another as the edges of tablet H.
When a vane, with part It in its finished state, is mounted in the jig the top and bottom surfaces 26, 27 respectively are parallel to the front and rear edges Ha, I! b of tablet H (Figure 4): these surfaces are, therefore, also parallel to the front and rear edges I211, I211 of tablet l2. Furthermore, the side edges of tablet H are parallel to surfaces 28 of block I! but, of course, not to the corresponding side edges of tablet I2.
The jig is carried by a base 29 which is, in turn, mounted on the table 30 of, say a horizontal milling machine 3| (Figure 7). When the table 30 moves past the cutter 32, edge lid of tablet H is machined. The jig is mounted in base 29 with surfaces 26, 27 horizontal so that the machined edge I in. will be horizontal.
It is preferred to have a pair of spaced cutters 32 simultaneously to machine edges Ha and Ho of tablets H and [2.
When so machined the jig is remounted on base 29 with edges ill) and [2b uppermost and these are similarly machined. When the jig is laid with its side surfaces on base 29 the side edges of tablet H may be similarly machined. Thus, the vane is located in the jig by edge M and point l and then has one tablet (H) completely machined and the front and'rear edges of the other tablet (l2) machined without removal of the vane from the jig.
The vane is then mounted in a similarly constructed jig so arranged, however, that the side edges of tablet l2 are parallel with the side surfaces 28 of block l7these edges are then machined.
As shown in Figure 4, the base 29 is arranged to accommodate, at the same time, two jigs. In this way the edges of Ha, l2a of one vane may be machined simultaneously with edges Hb, I21) of another vane, the vanes being mounted side by side in the pair of jigs.
1. For use in the manufacture of guide vanes for axial-flow turbines and compressors in which the vanes have end tablets for locating the vanes in rings with the trailing edge of a vane forming a throat area with the nearest point on the convex side of an adjacent vane, the herein described method of machining the edges of the tablets which consists in pivotally mounting the vane on its trailing edge and clamping the vane at said nearest point on the convex side and at a point approximately opposite said nearest point on the concave side, and moving the vane past a cutter with an edge of a tablet in a position to be machined.
2. A repetition method of manufacturing a guide vane having integral locating means, which method comprises the steps of shaping the vane proper to its final configuration, supporting the guide vane by engaging the vane proper at the trailing edge and at a location on its convex face that would be opposite the trailing edge of an adjacent vane when the two vanes are correctly assembled together, and machining the locating means on the vane while it is so supported.
ADRIAN ALBERT LOMBARD. WALTER EDWARD DAZELEY.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 819,961 Vaughan May 8, 1906 1,033,921 Morton July 30, 1912 1,258,462 Rice Mar. 5, 1918 1,327,799 Beede Jan. 13, 1920 1,470,502 Steenstrup Oct. 9, 1923 1,740,800 Wiberg Dec. 24., 1929 1,770,058 Andrew July 3, 1930 1,841,196 Mass Jan. 12, 1932 1,910,943 Wiberg et al May 23, 1933 2,063,706 Soderberg Dec. 8, 1936 2,279,258 Allen et a1 Apr. 7, 1942 2,283,901 Arnold May 26, 1942 2,373,827 Halford et al. Apr. 17, 1945 2,392,281 Allen Jan. 1, 1946 FOREIGN PATENTS Number Country Date 276,765 Great Britain Sept. 8. 1927