CN110026630B

CN110026630B - Inner cavity variable tool cathode for electrochemical machining of large-distortion blade blisk

Info

Publication number: CN110026630B
Application number: CN201910326896.5A
Authority: CN
Inventors: 孙伦业; 陈浩; 王晖
Original assignee: Anhui University of Science and Technology
Current assignee: Anhui University of Science and Technology
Priority date: 2019-04-23
Filing date: 2019-04-23
Publication date: 2020-04-14
Anticipated expiration: 2039-04-23
Also published as: WO2020215606A1; LU101448B1; CN110026630A

Abstract

The invention discloses an inner cavity variable tool cathode for an integral blade disc of a large-distortion blade through electrolytic machining, and belongs to the technical field of integral blade disc electrolytic machining. The method is characterized in that: the cathode structure is formed by combining a plurality of connecting rods into the shape of the bottom section of a blade, wherein a part of the connecting rods are provided with telescopic connecting rods and are arranged in a cathode shell, and the cathode shell is fixed on a cathode clamp; both sides of the cathode clamp are provided with a plurality of rotatable bases, electric push rods are arranged on the bases, and probes at the tail ends of the electric push rods are arranged at the joints of the cathode connecting rods. When the cathode clamp is processed, the clamp driving shaft drives the cathode clamp, the cathode shell and the internal cathode connecting rod to synchronously rotate and feed, and the electric push rod drives the cathode connecting rod to move to realize the change of the shape of the cathode inner cavity. The invention solves the problem that the traditional trepanning electrolytic machining, radial forming electrolytic machining and numerical control generating electrolytic machining are difficult to machine the large-distortion variable-section blisk blade.

Description

Inner cavity variable tool cathode for electrochemical machining of large-distortion blade blisk

Technical Field

The invention relates to a structural design of a cathode device for electrochemical machining of variable-section large-distortion blisk blades, and belongs to the technical field of blisk electrochemical machining.

Background

The aerospace technology becomes one of important indexes for measuring the scientific and technical level and comprehensive national strength of a country, the blisk is used as a core component in an aero-engine, and the efficient and high-quality manufacturing method of the blisk also becomes a key technology for developing the aero-engine. With the increasing thrust of aero-engines, the material of the blisk is constantly transiting to the direction of high strength, high hardness and high temperature resistance of titanium alloy, so that the processing of the blisk becomes a great problem in the manufacturing industry. Compared with the traditional numerical control milling, the electrochemical machining has the characteristics of high machining efficiency, no tool loss, no influence of material mechanical properties, no residual stress and the like, and the electrochemical machining becomes one of the key machining methods of the blisk by virtue of the unique advantages of the electrochemical machining.

With the development of aviation industry in China, the degree of importance of the country on the research and development work of aero-engines is continuously increased, and in recent years, a plurality of research institutions develop research on the electrochemical machining process method of blisks from different angles and obtain certain achievement. For example, the method of trepanning electrochemical machining is utilized to machine the blisk blade with the uniform cross section, and the machining method adopts an annular tool cathode, so that the structure is simple and the machining efficiency is high; the method is characterized in that a radial forming electrolytic machining method is utilized to pre-machine the blade grid channels, a common machining method for the conventional electrolytic machining of the integral blade disc is provided, for example, a multi-electrode spiral feeding integral impeller inter-blade runner electrolytic machining method is provided in Chinese patent No. 200910025834.7 of Julian et al, published in 7, 21, 2010, a plurality of tool cathodes arranged on the same plane and arranged on an electrolytic machining clamp are adopted to machine the blade grid channels of the integral blade disc at the same time, and the machining efficiency is greatly improved; the straight line blade of the blade disc can be unfolded by utilizing the cathode of the straight line blade tool and combining with a numerical control machine to control the straight line blade to process the straight line blade.

Three processing methods, namely nesting electrochemical machining, radial forming electrochemical machining and numerical control generating electrochemical machining, have the characteristics respectively, but have the limitations. Only the blade disc blades with the equal sections can be processed by the sleeve material electrolytic processing; the radial forming electrolytic machining belongs to the preprocessing of a blade grid channel, the motion mode of a cathode is single radial feeding or spiral feeding, and the problems of uneven distribution of fine machining allowance of blades and even incapability of machining of a blisk with large blade twisting degree can be caused; the motion trail of the cathode of the numerical control generating electrochemical machining tool is a straight-line developable surface, and the blade disc blade with a distorted complex profile cannot be machined. Aiming at the problem that the existing electrolytic machining technology is difficult to machine the large-distortion variable-section blisk, a new electrolytic machining cathode device and a new electrolytic machining method are imperatively researched.

Disclosure of Invention

The invention aims to solve the problems and provides an inner cavity variable tool cathode for an electrochemical machining blisk with large twisted blades.

The invention adopts the following technical scheme for realizing the purpose: introducing a three-dimensional model of the blisk into CAD software, carrying out equidistant cutting on the blade by adopting a parallel cutting method and extracting contour lines of all sections; selecting the outline of the maximum section at the bottom of the blade, carrying out bias stretching treatment on the outline to obtain an entity, and dividing the entity into a plurality of connecting rods according to the structural characteristics of the entity, wherein part of the connecting rods can be contracted. And (3) carrying out motion simulation after assembling the connecting rods, setting motion modes and step lengths of the connecting rods according to the external profile of the target blade, reserving machining allowance, taking the motion track of the inner cavity of the cathode connecting rod as the external profile of the blade profile, and finally extracting the motion track of the connecting part of each connecting rod.

The invention provides a cathode of an inner cavity variable tool for an electrochemical machining large-distortion blade blisk, aiming at the problem that the conventional methods such as trepanning electrochemical machining, radial forming electrochemical machining, numerical control generating electrochemical machining and the like are difficult to machine the large-distortion variable-section blisk blade.

The cathode of the inner cavity variable tool for the electrochemical machining of the large-distortion blade blisk is composed of a cathode clamp, a cathode shell and a cathode connecting rod; the upper part of the cathode clamp is connected with a clamp driving shaft, and the clamp driving shaft is rotationally connected with the cathode clamp; both sides of the cathode clamp are provided with an electrolyte inlet and a rotatable base groove; a plurality of rotatable bases are arranged in the rotatable base grooves, and electric push rods are arranged on the rotatable bases; and the probe at the front end of the electric push rod is fixedly connected with the joint of each cathode connecting rod.

Both sides of the bottom of the cathode clamp are provided with cathode supporting seats, the upper parts of the cathode supporting seats are cathode shells, and the cathode shells are fixedly connected with the cathode supporting seats; the cathode shell is composed of a cathode cover plate and a cathode bottom plate, and the bottom surface of the cathode bottom plate is an arc-shaped curved surface.

A sliding vane sliding groove is formed in the cathode cover plate, is a sliding way for rotating the sliding vane, and is connected to the cathode cover plate through a pin; a first contraction connecting rod is fixed on the cathode bottom plate and is connected with a first contracted connecting rod; the first contraction connecting rod, the first contracted connecting rod, the second contracted connecting rod, the third contracted connecting rod and the connecting rods are sequentially connected end to end.

The cathode connecting rods are connected end to end in sequence, and can rotate relatively to form the required blade section profile; the first, second and third contracted connecting rods can be respectively contracted into the first, second and third contracted connecting rods.

The cathode connecting rods are all designed into an integral structure with linkage pieces at the outer sides, the linkage pieces at the outer sides of the connecting rods and the cathode bottom plate can ensure that the material of the cascade channel is completely removed in the machining process, and the linkage pieces at the outer sides of the adjacent connecting rods are distributed in a vertically staggered manner.

The cathode bottom plate, the bottom surfaces of the cathode connecting rods, the inner cavity surface and the bottom surfaces of the connecting rod outer side linkage pieces are simultaneously used as processing surfaces to participate in processing.

One end of the rotating slip sheet is connected to the cathode cover plate through a pin, the other end of the rotating slip sheet is arranged in the slip sheet sliding groove, and the rotating slip sheet can rotate around the pin and shrink into the slip sheet sliding groove of the cathode cover plate.

The inner cavity of the cathode cover plate is provided with four electrolyte nozzles, electrolyte flows into the cathode cover plate from an electrolyte inlet through the cathode supporting seat, an electrolyte flow channel is formed in the cathode cover plate, the electrolyte is respectively supplied to the four electrolyte nozzles through the flow channel, and the electrolyte is sprayed out of the nozzles, flows to the processing bottom surface through the processing surface of the inner cavity and finally flows out of two sides of the blade.

In the processing process, the cathode clamp, the cathode shell and each cathode connecting rod are fixedly connected and synchronously rotate and feed.

The invention has the beneficial effects that: the invention provides an inner cavity variable tool cathode for an electrochemical machining large-distortion blade blisk, which can realize the change of the shape of the inner cavity of the cathode in the machining process, so that the machined blade profile is close to the target blade profile to the maximum extent, the reserved leveling allowance can be effectively reduced, and the allowance distribution is more uniform.

In the machining process, the driving shaft is rotated to drive the tool cathode to synchronously rotate and feed, and the shape of the inner cavity of the cathode is gradually changed while feeding; by adopting the cathode structure, a single variable cross-section twisted blade disc blade can be directly processed in the movement mode, the blade profile is formed at one time, the distribution of processing allowance is uniform, and the processing efficiency is high.

After the profile of a single blade is machined, retracting the tool cathode according to a feed route, and retracting the cathode to an initial position; when the cathode processes the next blade in the same motion mode after the blisk is indexed, the machined blade cannot be secondarily corroded.

When processing, along with rotatory drive shaft drives instrument negative pole synchronous revolution and feeds, rotate the gleitbretter and gradually shrink into in the cathode shell, this telecontrol equipment can effectively solve because the great passageway top processing that leads to of cascade passageway opening angle is not enough, the problem of bottom processing overcut.

The invention provides a blisk electrolytic machining method with wide application range; aiming at different blisk models, a cathode structure is designed according to the blade profile, a cathode connecting rod contraction mode and a tool cathode feed route are set through motion simulation, and the motion trail of the cathode connecting rod is attached to the blade profile.

When the blade machining device is used, electrolyte flows into the cathode cover plate from an electrolyte inlet through the cathode supporting seat, an electrolyte flow channel is formed in the cathode cover plate, the electrolyte is respectively supplied to the four electrolyte spray heads through the flow channel, and the electrolyte is sprayed out of the spray heads, flows to the machining bottom surface through the inner cavity machining surface and finally flows out of two sides of the blade.

Drawings

FIG. 1 is a schematic view of blisk blade electrochemical machining;

FIG. 2 is a schematic view of the overall structure of the cathode of the tool;

FIG. 3 is a schematic sectional top view of a blisk blade electrochemical machining;

FIG. 4 is a schematic view of the cathode housing and internal connecting rods;

FIG. 5 is a schematic view of a cathode connecting rod structure;

FIG. 6 is a schematic view of the cathode connecting rod driven by the electric push rod;

FIG. 7 is a schematic view of a cathode connecting rod in a contracted configuration;

reference numbers in the figures: the cathode clamping device comprises a cathode clamping device 1, a cathode shell 2, a cathode connecting rod 3, an electric push rod 4, a clamping device driving shaft 5, a blisk 6, a rotating slide 7, a slide chute 8, a pin 9, an electrolyte spray head 10, an electrolyte inlet 11, a rotatable base groove 12, a rotatable base 13, a cathode supporting base 14, a cathode cover plate 21, a cathode bottom plate 22, a first contraction connecting rod 31, a first contracted connecting rod 32, a second contracted connecting rod 33, a second contracted connecting rod 34, a third contracted connecting rod 35, a third contracted connecting rod 36, a linkage piece 37, a probe 41 and a processed blisk blade 61.

Detailed Description

In order to make the technical means, embodiments, objectives and advantages of the present invention easy to understand, the following description will be given with reference to the accompanying drawings.

As shown in fig. 1-7, the cathode of the variable tool for the inner cavity of the blisk with the large twisted blades for the electrolytic machining comprises a cathode clamp 1, a cathode shell 2, a cathode connecting rod 3, an electric push rod 4, a clamp driving shaft 5, a blisk 6 and the like; one end of the clamp driving shaft 5 is fixedly arranged on the machine tool, and the other end of the clamp driving shaft is rotationally connected with the cathode clamp 1; both sides of the cathode clamp 1 are provided with an electrolyte inlet 11 and a rotatable base groove 12; a plurality of rotatable bases 13 are arranged in the rotatable base grooves 12, and motors are arranged in the rotatable bases 13; the rotatable base 13 is provided with an electric push rod 4, and a probe 41 at the front end of the electric push rod 4 is fixedly connected with the joint of each cathode connecting rod 3; both sides of the bottom of the cathode clamp 1 are provided with cathode supporting seats 14, the upper parts of the cathode supporting seats 14 are provided with cathode shells 2, and the cathode shells 2 are fixedly connected with the cathode supporting seats 14; the cathode shell 2 is composed of a cathode cover plate 21 and a cathode bottom plate 22; during machining, a machined blade disc is connected with a positive electrode of a power supply, a cathode structure is connected with a negative electrode of the power supply, a machine tool drives a cathode clamp 1 to rotate and feed through a clamp driving shaft 5, the rotatable base 13 and an electric push rod 4 realize the change of the shape of an inner cavity of a cathode connecting rod 3 through controlling the movement of a probe 41 during feeding, the movement track of the probe 41 simulates the movement track of the joint of each connecting rod, after a single blade is machined, the cathode returns to the initial position, and the integral blade disc 6 rotates for a certain angle to machine the next blade in the same step; through the device with above-mentioned motion mode can directly process out single variable cross section distortion blade profile, can effectively reduce the flattening surplus of reserving again, make the surplus distribution more even.

As shown in fig. 1-7, the cathode of the cavity-changeable tool for electrochemical machining of the blisk with large twisted blade according to the present invention is characterized in that four electrolyte nozzles 10 are installed in the cavity of the cathode cover plate 21, during machining, electrolyte flows into the cathode cover plate 21 from the electrolyte inlet 11 through the cathode support base 14, electrolyte channels are formed in the cathode cover plate 21, the electrolyte is respectively supplied to the four electrolyte nozzles 10 through the electrolyte channels, and the electrolyte is sprayed out from the nozzles, flows to the machined bottom surface through the machined surface of the cavity, and finally flows out from the two sides of the blade.

As shown in fig. 1-7, the cathode of the variable tool for the inner cavity of the blisk with the large twisted blade according to the present invention, one end of the rotating slip sheet 7 is connected to the cathode cover plate 21 through a pin 9, the other end is disposed in the slip sheet sliding chute 8, and the rotating slip sheet 7 can rotate around the pin 9 and shrink into the slip sheet sliding chute 8 of the cathode cover plate 21; the moving device can effectively solve the problems of insufficient processing at the top of the channel and over-cutting processing at the bottom of the channel caused by larger opening angle of the cascade channel.

As shown in fig. 1-7, the cathode of the variable tool for inner cavity of the electrochemical machining of the large twisted blade blisk according to the present invention, a first contraction connecting rod 31 is fixed on the cathode bottom plate 22, and the first contraction connecting rod 31 is connected with a first contracted connecting rod 32; the first contraction connecting rod 31, the first contracted connecting rod 32, the second contraction connecting rod 33, the second contracted connecting rod 34, the third contraction connecting rod 36, the third contracted connecting rod 35 and all the connecting rods are connected end to end in sequence; the cathode connecting rods 3 are designed into an integral structure with linkage pieces 37 on the outer side; during processing, the rotatable base 13 and the electric push rod 4 drive the cathode connecting rod 3 to move according to the simulation track through the control probe 41, so that the shape of the inner cavity of the cathode connecting rod 3 is continuously changed to process the variable-section blisk blade.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. The utility model provides a but the variable instrument negative pole of inner chamber of electrolytic machining big distortion blade blisk, this negative pole structure is applied to blisk electrolytic machining field, its characteristic as follows:

the cathode of the inner cavity variable tool for the electrochemical machining of the large-twisted blade blisk is composed of a cathode clamp (1), a cathode shell (2) and a cathode connecting rod (3);

the upper part of the cathode clamp (1) is connected with a clamp driving shaft (5), and the clamp driving shaft (5) is rotationally connected with the cathode clamp (1); both sides of the cathode clamp (1) are provided with an electrolyte inlet (11) and a rotatable base groove (12); a plurality of rotatable bases (13) are arranged in the rotatable base grooves (12), and electric push rods (4) are arranged on the rotatable bases (13); the probe (41) at the front end of the electric push rod (4) is fixedly connected with the joint of each cathode connecting rod (3);

both sides of the bottom of the cathode clamp (1) are provided with cathode supporting seats (14), the upper parts of the cathode supporting seats (14) are provided with cathode shells (2), and the cathode shells (2) are fixedly connected with the cathode supporting seats (14); the cathode shell (2) is composed of a cathode cover plate (21) and a cathode bottom plate (22), and the bottom surface of the cathode bottom plate (22) is an arc-shaped curved surface;

a sliding vane sliding groove (8) is formed in the cathode cover plate (21), the sliding vane sliding groove (8) is a sliding way for rotating the sliding vane (7), and the rotating sliding vane (7) is connected to the cathode cover plate (21) through a pin (9); a first contraction connecting rod (31) is fixed on the cathode bottom plate (22), and the first contraction connecting rod (31) is connected with a first contracted connecting rod (32); the first contraction connecting rod (31), the first contracted connecting rod (32), the second contracted connecting rod (33), the second contracted connecting rod (34), the third contracted connecting rod (36), the third contracted connecting rod (35) and all the connecting rods are connected end to end in sequence;

four electrolyte spray heads (10) are installed in the inner cavity of the cathode cover plate (21), electrolyte flows into the cathode cover plate (21) from an electrolyte inlet (11) through a cathode supporting seat (14), an electrolyte flow channel is formed in the cathode cover plate (21), the electrolyte is respectively supplied to the four electrolyte spray heads (10) through the flow channel, and the electrolyte is sprayed out of the spray heads, flows to the processed bottom surface through the inner cavity processing surface and finally flows out of two sides of the blade.

2. The cathode of the variable inner cavity tool for the electrochemical machining of the large-twisted blade blisk according to claim 1, wherein: the cathode connecting rods (3) are connected end to end in sequence, and can rotate relatively to form the required blade section profile; the first contracted connecting rod (32), the second contracted connecting rod (34) and the third contracted connecting rod (35) can be respectively contracted into the first contracted connecting rod (31), the second contracted connecting rod (33) and the third contracted connecting rod (36).

3. The cathode for the variable-cavity tool for the electrochemical machining of the blisk with the large twisted blade as claimed in claim 1, wherein: the cathode connecting rods (3) are all designed into an integral structure with linkage pieces (37) at the outer sides, the linkage pieces (37) at the outer sides of the connecting rods and the cathode bottom plate (22) can ensure complete removal of cascade channel materials in the processing process, and the linkage pieces (37) at the outer sides of the adjacent connecting rods are distributed in a vertically staggered manner.

4. The cathode for the variable-cavity tool for the electrochemical machining of the blisk with the large twisted blade as claimed in claim 1, wherein: the cathode bottom plate (22) and the bottom surfaces of the cathode connecting rods (3), the inner cavity surface and the bottom surface of the connecting rod outer side linkage piece (37) are simultaneously used as processing surfaces to participate in processing.

5. The cathode for the variable-cavity tool for the electrochemical machining of the blisk with the large twisted blade as claimed in claim 1, wherein: one end of the rotating slip sheet (7) is connected to the cathode cover plate (21) through a pin (9), the other end of the rotating slip sheet is arranged in the slip sheet sliding groove (8), and the rotating slip sheet (7) can rotate around the pin (9) and shrink into the slip sheet sliding groove (8) of the cathode cover plate (21).

6. The cathode for the variable-cavity tool for the electrochemical machining of the blisk with the large twisted blade as claimed in claim 1, wherein: in the processing process, the cathode clamp (1), the cathode shell (2) and each cathode connecting rod (3) are fixedly connected and synchronously rotate and feed.