GB1594965A

GB1594965A - Method and apparatus for the manufacture of parts of rotary fluid machines

Info

Publication number: GB1594965A
Application number: GB1775377A
Authority: GB
Original assignee: Rylewski E M
Current assignee: Rylewski E M
Priority date: 1976-04-29
Filing date: 1977-10-28
Publication date: 1981-08-05
Also published as: DE2719316A1; CA1096595A; JPS52155403A; FR2349381B1; FR2349381A1

Description

(54) A METHOD AND APPARATUS FOR THE MANUFACTURE OF PARTS OF ROTARY FLUID MACHINES (71) I, EUGENIUSZ MICHAL RYLEWSKI, a citizen of France, of 43 bis Avenue du Gal Leclerc, 78460 St. Remy les Chevreuse, France, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a method and apparatus for the manufacture of a machine part containing a spiral-like passage of revolution for use in a rotary fluid machine in which the conversion of pressure energy of fluids is obtained by the circulation of at least two spaced vane members in at least one spiral-like passage of revolution in the form of a channel defined by a pair of rib members having top surfaces and side walls, and wherein the vane members are parts of at least two vane wheels each of which is mounted for rotation about its own axis in a first part of said machine, said spiral-like passages of revolution are formed in a second part of said machine and at least one of said first and second parts of said machine is rotatable, and wherein said spiral-like passages of revolution are generated by a combined rotation of said vane members about the axis of rotation of their respective vane wheels and by rotation of said first part of said machine in relation to said second part of said machine.

It is difficult to manufacture the aforesaid rotary fluid machine part containing the spiral-like passage of revolution, in the form of channels or grooves by conventional machining. Moreover, the difficulty increases the more the cross section of the channel to be obtained has a configuration which limits the possibilities of an axial feed of a machining tool in relation to the disc in which the channels are to be formed.

The manufacturing of the channels or grooves in a disc or similar items, is most often done by milling. In this case, one or more milling cutter turning at high speed around their own axes are put into movement in relation to the disc so as to generate the desired trajectory. However, to create the aforesaid channels by milling requires a great number of work passes to generate in successive movements different limiting surfaces and also to generate different channels.

Such a process of manufacturing is, therefore, long and delicate and difficult to achieve. It generates difficult tooling problems and very often does not result in channels which have the desired sealing while cooperating with the vanes or similar devices.

According to the invention, there is provided a method for the manufacture of a machine part containing a spiral-like passage of revolution for use in a rotary fluid machine in which the conversion of pressure energy of fluids is obtained by the circulation of at least two spaced vane members in at least one spiral-like passage of revolution in the form of a channel defined by a pair of rib members having top surfaces and side walls, and wherein the vane members are parts of at least two vane wheels each of which is mounted for rotation about its own axis in a first part of said machine, said spiral-like passages of revolution are formed in a second part of said machine and at least one of said first and second parts of said machine is rotatable, and wherein said spiral-like passages of revolution are generated by a combined rotation of said vane members about the axis of rotation of their respective vane wheels and by rotation of said first part of said machine in relation to said second part of said machine, said method comprising the steps of: providing at least one vane cutting tool having cutting sectors formed in the shape of the vane members of said vane wheels of said machine, providing a blank member to be formed into said second part of said machine, rotating said blank member about a fixed axis of rotation to an extent corresponding to the relative rotation between said first and second parts of said machine, rotating said vane cutting tool about a second axis of rotation which is in the same direction as the axis of rotation of said vane wheels in said first part of said machine, and bringing said rotating vane cutting tool into cutting engagement with said rotating blank member according to the same combined relative law of movement as between said rotating vane wheels and said relative rotation between said first and said second parts of said machine during operation of said machine, whereby said vane cutting tool cutting sectors cut into said blank member in a direction normal to the direction of rotation of said second axis of rotation to thereby cut in the manner of a turning operation at least one spiral channel in said blank member which forms said at least one spiral-like passage of revolution in which said at least two spaced vane members circulate during operation of said rotary fluid machine.

The machining operation is then a simple planing or turning operation, providing simultaneous production of all the spiral-like passages required for a disc which is to form either the rotor or stator of the rotary fluid machine. Such an operation can be carried out at high speed which leads to fast production of the discs containing the spiral-like channels or grooves. The machining can be done in one work pass or in several successive work passes.

The invention also includes an apparatus for carrying out said method, said apparatus comprising: at least one vane cutting tool having cutting sectors formed in the shape of the vane members of said vane wheels of said machine, a blank member to be formed into said second part of said machine, means mounting said blank member for rotation about a first axis of rotation to an extent corresponding to the relative rotation between said first and second parts of said machine.

means mounting said vane cutting tool for rotation about a second axis of rotation which is in the same direction as the axis of rotation of said vane wheels in said first part of said machine, and means bringing said rotating vane cutting tool into cutting engagement with said rotating blank member according to the same combined relative law of movement as between said rotating vane wheels and said relative rotation between said first and second parts of said machine during operation of said machine, whereby said vane cutting tool cutting sectors cut into said blank member in a direction normal to the direction of rotation of said second axis of rotation to thereby cut in the manner of a turning operation at least one channel in said blank member which forms said at least one spiral-like passage of revolution in which said at least two spaced vane members circulate during operation of said rotary fluid machine.

The invention may be utilised in respect of any rotary fluid machine in which the channels are formed on a cylinder, a cone or a portion of a sphere. Thus, the invention is useful with respect to centrifugal machines generally.

The foregoing and further features of the invention may be more readily understood from the following description of some preferred embodiments thereof, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a stator for a rotary fluid machine in the form of a disc having spiral-like passages of revolution in the form of channels or grooves; Figure 2 is a fragmentary schematic view of a portion of a rotor for a rotary fluid machine having vane wheel adapted to cooperate with the stator shown in Figure 1; Figure 3 is a fragmentary schematic view, partly in section, of a portion of the rotor shown in Figure 2; Figure 4 is an enlarged, fragmentary schematic view, partly in elevation and partly in cross section, of a channel of the stator of Figure 1, the channel being defined by side and bottom walls formed by the disc and a top wall formed by the cooperating rotor of Figure 2; Figure 5 is a schematic view in elevation of a disc to be machined according to the method and apparatus of the invention; Figure 6 is a view in elevation of the machining apparatus of the invention; Figure 7 is a plan view of the apparatus shown in Figure 6; Figure 8 is a schematic view of the vane cutting tool for use according to the invention; Figure 9 is an enlarged view in cross section of the vane of Figure 2; Figure 10 is an enlarged schematic view of the vane cutting tool of Figure 8, and further shows in cross section the configuration of its different vane branches or sectors; Figure 11 is a view in front elevation of a stator with spiral-like passages formed therein according to the method of the invention and using the vane cutting tool of Figure 10; Figure 12 is a view analogous to Figure 25, showing another channel structure for a stator for a rotary fluid machine; Figure 13 is a fragmentary schematic view in perspective of another embodiment of a vane cutting tool for use according to the invention having divergent edges; Figure 14 is a schematic view illustrating the first phase of the method of manufacture of the invention; Figure 15 is a view similar to Figure 14, illustrating the second phase of said method of manufacture; Figure 16 is a view similar to Figures 14 and 15, illustrating the third phase of said method of manufacture; Figure 17 is a view similar to Figures 14 to 16, illustrating the final phase of said method of manufacture; Figure 18 is a view in front elevation of a vane wheel for a rotary fluid machine; Figure 19 is a schematic view of an adapter mechanism mounted on a conventional lathe for carrying out said method of manufacture; Figure 20 is a view in a schematic section of a vane member; Figure 21 is a schematic view concerning a frontal edge of a vane member; Figure 22 is a perspective view of a vane tool with branches constructed in accordance with the invention; Figure 23 is a fragmentary schematic view, partly in section, illustrating the machining of a cylinder according to said method of manufacture; Figure 24 shows a cylinder mounted for machining according to said method of manufacture; Figure 25 is a fragmentary schematic view in axial section illustrating the manufacture of a disc of a centrifugal machine according to said method of manufacture; Figure 26 is a front view of the disc shown in Figure 25; Figure 27 is a view of a platetool for use according to the invention; Referring now to the drawings, the invention provides for the machining of a stator 11 with spiral-like passages of revolution in the form of channels or grooves, the centre lines of which are schematized at 12,, 122,123, 124, (Figure 1). The passages connect a central opening 13 of the stator with one or more peripheral fluid openings 14. Circulating in the channels 12 are vanes 15 of the vane wheels 16 (Figures 2 and 3), the latter being housed in the slots 17 made in a rotor 18 mounted for rotation relative to the stator 11 about the axis 19. The rotor 18 has on its side in front of the stator 11, a surface 21 which cooperates sealingly with the surface 22 of the stator 11 (Figure 4). The surface 22 is prolonged by side wall surfaces 23 and 24 (Figure 4) which define, with the bottom 25, a channel or groove 12.

In the structure shown schematically in Figures 2 and 4, the surfaces 21 and 22 are planar. In other structures, the cooperating surfaces of the rotor and stator are curved and form a surface of revolution about the axis 19. Each of the vane wheels 16 is independently mounted for rotation about its own axis 26, which is transverse to the axis 19.

For the machining of the channels or the grooves, a stator blank 20 (Figure 5) to be machined, is secured to the part-holder 31 (Figures 6 and 7) of a spindle 32 of a lathe.

The blank 20 therefore rotates around the horizontal axis 33. The saddle 34 of the lathe can be displaced in one direction or the other by the axial feed means 35. On the saddle 34 is mounted a cross slide 36 which can be adjusted transversally by the cross feed means 37. On the cross slide 36 is mounted a tool-holder 38 carrying a vane tool 39.

The vane cutting tool 39 (Figures 8 and 10) has the shape of a rotary fluid machine vane wheel, i.e. it comprises branches or sectors 41 which have a contour corresponding fundamentally to the contour of the vanes of a vane wheel 16 (Figure 2) intended to circulate within the channels to be formed in the blank 20. Vane cutting tool 39 is fixed on the axis 42 of the toolholder 38 which is distant from the axis 33, and is driven for rotation about axis 42 by a positive transmission taken from the driving mechanism of the spindle 32.

A relative movement is imposed between the axis 42 of the toolholder and the spindle 32, the movement of which corresponds to the operation of the rotary fluid machine in which the stator is to be used.

The initial position of the vane cutting tool 39 is adjusted by the controls 37. By progressively moving the saddle 34 to the blank 20 by acting on the axial feed controls 35, the tool 39 forms, by its branches or sectors 41, in the material of the disc, spiral-like channels 12, the cross sections of which are conjugated with the contour of the operating portions of the vane tool sectors or branches 41.

When the desired depth is reached, the saddle 34 is displaced in the opposite direction, which removes the branches 41 from the grooves just formed.

In the structure shown on Figure 6, the mean plane of the body of the vane cuttmg tool 39 is above the axis of rotation of the workpiece 33. However, the invention provides for a mode of machining in which this mean plane passes through the axis 33 or below it.

The Figure 9 shows on an enlarged scale a cross section of the vane 15 of a vane wheel 16 which is intended to circulate within the channels being machined in blank 20. The edges 42 and 42' of the vane 15 are rounded and cooperate with the lateral walls or flanks of the channels of the stator by different generating lines depending on the position of the vane in a channel of the stator.

For the construction of the vane cutting tool 39 with five branches 41, there are chosen along sections 42 and 42' of the edges of the vane 15, in addition to the extremities 42.2 and 42.3, three other equidistant points, namely 42.1 half way between 42.2 and 42.3, 42.4 equidistant from 42.1 and 42.2, and 42.5 equidistant from 42.1 and from 42.3. The same procedure is done on the opposite edge 42'. A transversal edge 43.1 of the branch 41.1 of the vane tool 39 has a shape of a flat hexagon (Figure 10), having opposite apexes 47.1 and 47'.1 corresponding to points 42.1 and 42'.1 on vane 15 in Figure 9. The sides of vane 15 originating in these two apexes, 44.1 and 45.1 on one side and 44'.1 and 45'.1 on the other, are oblique to satisfy the conditions of machining of the tool 43.1 and are connected together by the long sides 46.1 and 46' 1. The branch 41.1 of the tool 39 is, therefore, operative in the second 43.1 by its edges 47.1 and 47'.1.

In the same way, the branch 41.2 of the vane cutting tool 39 is operative, in the plane 43.2 by its edges 47.2 and 47'2 which corresponds to the angles 42.2 and 42'.2 of the vane 15. The branch 41.3 has edges as shown in 47.3 and 47'.3 on the section made by the plane 43.3 which correspond to angles 42.3 and 42'.3 of vane 15; branch 41.4 has edges as shown in 47.4 and 47'.4 which correspond to angles 42.4 and 42'.4 of vane 15; branch 41.5 has edges as shown in 47.5 and 47'.5 which correspond to angles 42.5 and 42'.5 of vane 15.

Tools having branches or sectors of different types are provided for different phases of machining: rough machining, normal machining and, if needed, finishing machining.

The invention provides for a law of movement in relation to the number of branches of the vane tool and in relation to the number of the channels to be machined so the same branch successively machines all the different channels to be made. This is the case, for example, when the vane cutting tool has five branches and the disc to be machined has four channels.

Means are also provided for angular displacement of the vane cutting tool about its own axis of rotation after a cut so that one branch of the vane cutting tool plays the role of another branch. Alternatively, or in addition, the disc member may be angularly displaced about its axis of rotation.

Figure 11 shows a stator 48 with channels obtained with a tool as shown in Figure 10.

The stator 48 has channels 49, one extremity of which emerges into a central opening 50 and the other extremity ends at the periphery 51. Lines 52 and 53 represent the intersections of the channels with the frontal face 54 of the stator.

Means are provided for machining channels or grooves in a part for a rotary fluid machine, the cross-sections of which are such that conventional machining with a tool having a shape corresponding to the shape of the channels would cause, dunng the axial feed, an excessive removal of material which would finally not permit the desired profile for the groove or the channel to be obtained.

This is the case when the bottoms of the channels are wider than the distance between their sides at the tops. A rotary fluid machine which has a stator with channels satisfying this condition has a particularly high discharge flow.

Such a stator is shown on Figure 12. The channel 55 connecting the central orifice 56 with the periphery 57 is limited, in addition to the bottom 58, by two lateral walls. If, for example for the portion 59 of the lateral wall 60 close to the periphery 57, a tool as shown diagramatically in 61 with its operative edge 62 was machining the portion 59 close to the bottom 58, it would remove, at the beginning of the cutting, an excessive portion of the material not allowing at the end to keep the material which forms the front side 63 of the channel 55.

To machine such a disc, the invention provides for a way which departs from the vane 71 (Figure 13) of a vane wheel designed to cooperate with the channels 55. The vane has a frdntal side 72, fit to cooperate with the bottom 58, wider than the sections which are closer to the root of the vane. The section closest to the body of the wheel is shown at 73. The lateral sides 74 and 75 of the vane are here in the shape of a truncated cone, the axis of the trunk of the cone being the mean line 76 of the vane. In this event, there is provided a vane tool having simulated vanes of reduced size and less divergent than the vane 71, and the sides 77 and 78 of which are on the trunk of the cone of the axis 76, with smaller apex angle of the cone. The reduction of the divergence is chosen such that the simulated vane 79 corresponds in scale to the vane of a vane wheel of a rotary fluid machine in which the channels of the stator can be obtained by machining as above explained. Starting with this reduced-size vane, a tool is designed with branches as defined above in reference with Figures 9 and 10.

Referring now more particularly to Figures 14 to 17, there is illustrated a method of manufacture utilising a tool 101 constructed as described above. Thus the branches 102 correspond to said reduced-size vane and the radial edges 103 and 104 are only slightly divergent i.e. depart slightly from parallelism. By a longitudinal displacement of the saddle 34 in the direction shown by the arrow f (Figure 14), the vane tool 101 cuts in the disc 20 spiral-like groove whose cross-sec tions are conjugated with those of branches 102. The direction of rotation of the tool 101 around its axis 99 is shown by the arrow f,.

Figure 15 corresponds to the second phase of machining. It is distinct from the first phase simply by the introduction into the transmission, interposed between the spindle 32 of the machine-tool rotating around the axis 33 and the axis 42 of the tool-holder on which is mounted the vane tool 101, of a progressive variation which additionally advances the vane tool 101 in rotation in relation to the blank 20 in the direction shown by the dotted arrow f2. During this second phase, the side walls 105 of the groove, which have been cut during the first phase by the edges 104, upstream of the edges 103 if the reference is the rotation of the tool 101, are no longer cut.

On the other hand, the edges 103, downstream, are in operation due to the advancement in rotation introduced. In this way, the cross-sections of the grooves become bigger than the cross-sections of the individual branches 102 of the tool. At the end of the second phase, a channel or groove is limited, by the lateral wall 105 and by the lateral wall 106, the latter being at a greater distance from the wall 105 than the distance between the edges 103 and 104 of the tool 101.

During the third phase of the machining, (Figure 16), the transmission between the axis 33 and the axis 42 is progressively modified, but in the opposite direction to the modification introduced in the second phase, i.e. a delay in rotation is imposed as represented by the dotted arrow f3.

In this third phase, the edges 104 become operative while the edges 103 are inoperative. The lateral walls 106 are no longer machined, but the lateral flanks 105 are cut by the edges 104 till the wall 107 is obtained.

The resulting cross-section of the channel is thus still bigger than that obtained in the second phase.

In the final phase of the machining, (Figure 17), the transmission between the axis 42 is brought back to its initial position.

It is then possible to remove the tool from the channels by a translation of the saddle 34 as shown by the arrow f,.

The advances and delays in rotation of the second and the third phases correspond to the passage from the simulated vane 79 on Figure 15 to the real vane 71.

A disc with spiral-like grooves obtained in this way can then cooperate with a vane wheel the vanes of which are the size and shape of vanes 71. Such a wheel 110 is shown in Figure 18.

Figure 19 shows schematically an adaptor which, in combination with an ordinary lathe, enables a disc to be machined with spiral-like passages in the several phases as described above. To this end, the frame 201 of a conventional lathe is traversed by a tubular spindle shaft 203, put into rotation and held in the bearings 204 and 205. Inside the tubular shaft 203 is mounted a stationary shaft 202. The latter can be adjusted angularly around its longitudinal axis 206 by a lever 207 which can be located in several predetermined positions by an elastic pin 208 cooperating with the corresponding housings 209 fixed to the frontal face 210 of the frame.

A plate 212 is fixed to the head 211 of the annular shaft 203. The said plate 212 has fixedly mounted on its external frontal surface 213 a shaft 214 about which a spur gear 215 is mounted for rotation. The latter engages with a gear 216 secured to the extremity of the shaft 202. A bevel gear 217 is also mounted for rotation about shaft 214 and engages a bevel gear 218 secured to shaft 219 which is mounted for rotation in a bearing 220 situated at the extremity of the support 221 fixed to the plate 212. On the other extremity 222 of the shaft 219 of the gear 218 is mounted a vane tool 223 with its branches. The vane tool cuts a disc 224 to make a stator with channels. The disc 224 is mounted on a support 225, the latter being mounted on the saddle 226 of the lathe. The axial feed of the saddle 226 is controlled by the hand-wheel 227. The saddle 226 is carried by the carriage 228 mounted slidingly on the bench 229 of the lathe. The cross feed is controlled by the hand-wheel 230.

Once the first phase of machining is over, which corresponds to the median position of the handle 207, the second phase is obtained by an angular displacement in a predetermined direction of the stationary shaft 202 by the action on the handle 207. To free the handle 207, the elastic pin 208 is removed.

Then, after the second phase, the third phase is carried on by a rotation of the handle 207 in the opposite direction. The fourth phase, the removal of the tool 223, is obtained by bringing the handle to its central position.

The disc 224, the machining of which is finished, is then carried away by the action on the hand-wheel 230.

While using such adaptor mechanism, the disc 224 is stationary except for preliminary adjustments and axial feed. The law of movement is transmitted by the adaptor mechanism directly to the vane tool with its branches.

Figure 20 shows a section of a vane of the vane wheel for a rotary fluid machine, the section made through planes transverse to the mean plane which are asymmetrical instead of being symmetrical, in relation to the said mean plane, as was the case in the structures previously described.

Such a cross-section 231 comprises, on the upstream side, a portion 232 with a relatively small radius of curvature and, on the downstream side, a portion 233 with a larger radius of curvature. On the contrary, the opposite surface has, downstream, a portion 234 with a relatively large radius of curvature and upstream, a portion 235 with a relatively small radius of curvature. The mean plane 236, parallel to the downstream face 237 and to the upstream face 238 of the vane, is not perpendicular to either the external surface 239 of the channel or to the internal face 241 of the channel.

A rotary fluid machine with vane wheels, the vanes of which have a contour just defined with reference to Figure 20, takes advantage of the oil wedge and of the suction effect caused by the circulation of a vane in a spiral-like channel of the stator. It is beneficial for the operation of the machine.

The branches of a vane cutting tool for the machining of the channels with which will cooperate such vanes, are defined in the same manner as explained above.

Thus, as shown in Figure 21, the front portion of the branches of the tool is defined by the front side Ill of a vane. The latter is a portion of a spherical surface limited by two arcs 112 and 113 centred on the mean line 114 of the vane and also by rectilinear sides 115 and 116. A first branch of the tool comprises an edge 115.1 corresponding to the straight line which joins the extremities 112. 1 and 113.1 of the arcs 112 and 113. Another branch of the tool comprises an edge 115.2 which connects points 112.2 and 113.2. A third branch corresponds to the straight line 115.3 which connects points 112..3 and 113 3 A fourth edge corresponds to the straight line 115.4 joining the points 112 and 113.4. A fifth edge corresponds to the straight line 115.5 joining the points 112.5 and 113.5.

A vane cutting tool 301 is shown on a smaller scale in Figure 22. It comprises five branches 302.1-302.5. The edges of each of the branches are represented by dark lines.

On the branch 302.1 the lateral edges 316.1, 317.1 and the front edge 318.1 are connected together between the back face 319, lateral faces 320 and 321 and front face 322 of the branch. On the branch 302.3, for example, the lateral edges 316.3 and 317.3 and also the front edge 318.3 are located at the centre of the thickness of the branch. The manufacturing process, the machining device and the vane tools as described above, apply also to the machining of spiral-like passages in a body of revolution as a cylinder, a cone or a portion of a sphere.

Thus, a cylindrical blank 321 (Figures 23 and 24) has its front faces 322 and 323 held between lathe-centres 324 and 324' and is therefore, put into rotation. The machining is done by the branch 325 of the vane tool 326 mounted for rotation around the axis 327.

The arrow f schematises the direction of the feed during the machining. The law of movement between the rotation of cylindrical blank 321 around the axis 324 324' and the rotation of vane tool 326 around the axis 327 corresponds to the predetermined relative movement between the cylinder 321 with grooves and the vanes or the cooperating walls engaging the grooves in a rotary fluid machine. Figure 24 shows the grooves 328 obtained by machining blank 321 with tool 326.

The dotted lines 329 and 330 on Figure 23 show schematically the additional machining obtained by an advance or retardation in rotation imposed on the tool 326. This is to obtain channels the walls of which diverge from their external sides resulting in a machine for fluids with high discharge rate.

The invention provides also for the manufacturing of the centrifugal and centripetal impellers. Figure 25 shows such an impeller being manufactured. The impeller is mounted for rotation about the axis 333 between lathe-centers represented diagramatically at 331 and 332. The vane cutting tool is mounted for rotation about the axis 334 perpendicular to the axis 333. The vane cutting tool comprises branches 335. The work feed is schematised by the arrowf. The arrow f, schematises the adjustment of the tool before the machining.

The dotted lines 336 and 337 on Figure 25 represent schematically the positions of the lateral edges of a branch 335 of the tool during the second and the third phases of the machining in a case when channels with divergent sides are to be obtained. The channels 338 which are obtained are lim intersection 64 of the external plane of the rib of the stator with the bottom 55 in Figure 12.

A rib-tool 342 is thus defined. The different rib-tools 342.1 to 342.5 of the disc-tool have edges defined in the same manner as explained above so as to define the edges of the branches of a tool with branches.

In the same manner, the bottom 361 of the disc-tool 341 has cutting edges, some of them being shown by 362. These edges cut the front sides of the vanes in the circular blank mounted on the tool-holder of the lathe the spindle of which carries the disc 341. The ribs 342 cut the lateral sides of the vanes.

In a similar manner, vanes or similar members can be obtained for rotary fluid machines in which the channels are formed in a tool material on a cylindrical body, a conical body or an hour-glass body. The same applies to the formation of the vanes of centrifugal impellers. In all these cases, a tool having similar body with ribs is utilised.

The invention also provides for a disc with spiral-like grooves similar to the one shown in Figure 12 made in a material hard enough to permit it to machine a vane tool with branches which could then be utilised in turn, for machining a disc so as to form spiral-like channels as explained above.

WHAT I CLAIM IS: 1. A method for the manufacture of a machine part containing a spiral-like passage of revolution for use in a rotary fluid machine in which the conversion of pressure energy of fluids is obtained by the circulation of at least two spaced vane members in at least one spiral-like passage of revolution in the form of a channel defined by a pair of rib members having top surfaces and side walls, and wherein the vane members are parts of at least two vane wheels each of which is mounted for rotation about its own axis in a first part of said machine, said spiral-like passages of revolution are formed in a second part of said machine and at least one of said first and second parts of said machine is rotatable, and wherein said spiral-like passages of revolution are generated by a combined rotation of said vane members about the axis of rotation of their respective vane wheels and by rotation of said first part of said machine in relation to said second part of said machine, said method comprising the steps of: providing at least one vane cutting tool having cutting sectors formed in the shape of the vane members of said vane wheels of said machine, providing a blank member to be formed into said second part of said machine, rotating said blank member about a first axis of rotation to an extent corresponding to the relative rotation between said first and second parts of said machine, rotating said vane cutting tool about a second axis of rotation which is in the same direction as the axis of rotation of said vane wheels in said first part of said machine, and bringing said rotating vane cutting tool into cutting engagement with said rotating blank member according to the same combined relative law of movement as between said rotating vane wheels and said relative rotation between said first and said second parts of aid machine during operation of said machine, whereby said vane cutting tool cutting sectors cut into said blank member in a direction normal to the direction of rotation of said second axis of rotation to thereby cut in the manner of a turning operation, at least one spiral channel in said blank member which forms said at least one spiral-like passage of revolution in which said at least two spaced vane members circulate during operation of said rotary fluid machine.

2. A method of manufacture as claimed in claim 1 wherein said at least one spirallike passage of revolution is in the form of a channel having rounded side and bottom surfaces, and wherein a vane cutting tool having a plurality of cutting sectors is brought into cutting engagement with said blank member, the edges of each of said cutting sectors corresponding to different lines of cooperation between the rounded sides of said vane members and the rounded surfaces of said channel.

3. A method of manufacture as claimed in claim 1, wherein a multiplicity of cutting sectors of the same general configuration describing the profile of said vane members are successively brought into cutting engagement with said blank member, each of said multiplicity of cutting sectors being distinct from the others by the position of their cutting edges.

4. A method of manufacture as claimed in claim 1, including the additional steps of removing said vane cutting tool from cutting engagement with said blank member after cutting said channel to the desired depth, changing the relative positions of said vane cutting tool and said blank member by angularly displacing one of said first and second axes of rotation with respect to the other, and again bringing said vane cutting tool into cutting engagement with said blank member in their modified relative positions, whereby said at least one channel is cut larger than the size of the vane cutting tool cutting sectors.

5. A method of manufacture as claimed in claim 4, wherein said relative positions of said vane cutting tool and said blank member are firt modified by relative angular displacement of said first and second axes of rotation in a first direction and are thereafter again modified by relative angular displace

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. intersection 64 of the external plane of the rib of the stator with the bottom 55 in Figure 12. A rib-tool 342 is thus defined. The different rib-tools 342.1 to 342.5 of the disc-tool have edges defined in the same manner as explained above so as to define the edges of the branches of a tool with branches. In the same manner, the bottom 361 of the disc-tool 341 has cutting edges, some of them being shown by 362. These edges cut the front sides of the vanes in the circular blank mounted on the tool-holder of the lathe the spindle of which carries the disc 341. The ribs 342 cut the lateral sides of the vanes. In a similar manner, vanes or similar members can be obtained for rotary fluid machines in which the channels are formed in a tool material on a cylindrical body, a conical body or an hour-glass body. The same applies to the formation of the vanes of centrifugal impellers. In all these cases, a tool having similar body with ribs is utilised. The invention also provides for a disc with spiral-like grooves similar to the one shown in Figure 12 made in a material hard enough to permit it to machine a vane tool with branches which could then be utilised in turn, for machining a disc so as to form spiral-like channels as explained above. WHAT I CLAIM IS:

1. A method for the manufacture of a machine part containing a spiral-like passage of revolution for use in a rotary fluid machine in which the conversion of pressure energy of fluids is obtained by the circulation of at least two spaced vane members in at least one spiral-like passage of revolution in the form of a channel defined by a pair of rib members having top surfaces and side walls, and wherein the vane members are parts of at least two vane wheels each of which is mounted for rotation about its own axis in a first part of said machine, said spiral-like passages of revolution are formed in a second part of said machine and at least one of said first and second parts of said machine is rotatable, and wherein said spiral-like passages of revolution are generated by a combined rotation of said vane members about the axis of rotation of their respective vane wheels and by rotation of said first part of said machine in relation to said second part of said machine, said method comprising the steps of: providing at least one vane cutting tool having cutting sectors formed in the shape of the vane members of said vane wheels of said machine, providing a blank member to be formed into said second part of said machine, rotating said blank member about a first axis of rotation to an extent corresponding to the relative rotation between said first and second parts of said machine, rotating said vane cutting tool about a second axis of rotation which is in the same direction as the axis of rotation of said vane wheels in said first part of said machine, and bringing said rotating vane cutting tool into cutting engagement with said rotating blank member according to the same combined relative law of movement as between said rotating vane wheels and said relative rotation between said first and said second parts of aid machine during operation of said machine, whereby said vane cutting tool cutting sectors cut into said blank member in a direction normal to the direction of rotation of said second axis of rotation to thereby cut in the manner of a turning operation, at least one spiral channel in said blank member which forms said at least one spiral-like passage of revolution in which said at least two spaced vane members circulate during operation of said rotary fluid machine.

ment of said first and second axes of rotation in a second direction opposite to said first direction.

6. Apparatus for the manufacture of a machine part containing a spiral-like passage of revolution for use in a rotary fluid machine in which the conversion of pressure energy of fluids is obtained by the circulation of at least two spaced vane members in at least one spiral-like passage of revolution in the form of a channel defined by a pair of rib members having top surfaces and side walls, and wherein the vane members are parts of at least two vane wheels each of which is mounted tt station about its own axis itl a first part of said machine, said spiral-like passages of revolution are formed in a second part of said machine and at least one of said first and second parts of said machine is rotatable, and wherein said spiral-like passages of revolution are generated by a combined rotation of said vane members about the axis of rotation of their respective vane wheels and by rotation of said first part of said machine in relation to said second part of said machine, said apparatus comprising: at least one vane cutting tool having cutting sectors formed in the shape of the vane members of said vane wheels of said machine, a blank member to be formed into said second part of said machine, means mounting said blank member for rotation about a first axis of rotation to an extent corresponding to the relative rotation between said first and second parts of said machine, means mounting said vane cutting tool for rotation about a second axis of rotation which is in the same direction as the axis of rotation of said vane wheels in said first part of said machine, and means for bringing said rotating vane cutting tool into cutting engagement with said rotating blank member according to the same combined relative law of movement as between said rotating vane wheels and said relative rotation between said first and second parts of said machine during operation of said machine, whereby said vane cutting tool cutting sectors cut into said blank member in a direction normal to the direction of rotation of said second axis of rotation to thereby cut in the manner of a turning operation at least one channel in said blank member which forms said at least one spiral-like passage of revolution in which said at least two spaced vane members circulate during operation of said rotary fluid machine.

7. Apparatus as claimed in claim 6, including means to progressively angularly displace, in either of two opposite directions, said first and second axes of rotation so as to modify the relative positions of said vane cutting tool mounting means and blank member mounting means.

8. Apparatus as claimed in claim 7, wherein said blank member is secured to a lathe spindle shaft mounted for rotation about a horizontal axis.

said vane cutting tool is secured to another shaft mounted for rotation about a vertical axis, and including means for angularly displacing each of said spindle shaft and said another shaft from their respective horizontal and vertical axes of rotation to thereby modify the relative positions of sand vane cutting tool and said blank member.

9. A method and apparatus for the manufacture of a machine part containing a spiral-like passage of revolution for use in a rotary fluid machine of the kind described, substantially as hereinbefore described with reference to the accompanying drawings.