A non-contact electrolytic trimming method and fixture for the cantilever beam boot of a fingertip

Abstract

The present invention relates to a method for non-contact electrolytic finishing of the cantilever beam boot portion of a fingertip piece, comprising: staggeredly stacking a plurality of fingertip pieces on a lower pressing plate and installing an upper pressing plate, trimming the fingertip boots on the stacked fingertip pieces, and installing them in the inner cavity of a fixture base to achieve double positioning of the grouped fingertip pieces; fixing the grouped fingertip pieces, installing ceramic bearings and electrodes, and connecting a power supply and an electrolyte conduit; introducing the electrolyte in the electrolyte conduit into a processing area through the electrodes; driving the electrodes to rotate at a set angular velocity, and turning on the power supply when entering a speed stability range; applying a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots on the stacked fingertip pieces. The present invention also relates to a fixture for non-contact electrolytic finishing of the cantilever beam boot portion of a fingertip piece. The purpose of the non-contact electrolytic finishing method and fixture for the cantilever beam boot portion of a fingertip piece is to solve the problem of how to improve the surface quality of the fingertip structure and ensure reliable sealing.

Description

Technical Field

[0001] The invention relates to the technical field of electrolytic machining technology, and in particular to a non-contact electrolytic finishing method and a fixture for a cantilever beam boot portion of a fingertip piece. Background Art

[0002] As a contact seal, a fingertip seal typically consists of a stack of precision-machined thin metal sheets and front and rear baffles. These sheets and baffles are pinned and connected by rivets, welding, and screws. Each sheet is machined with several circumferentially evenly spaced fingertips—flexible, slender fingertip beams—with their free ends resting on the surface of the engine shaft. During assembly, the sheets are staggered to ensure that the gaps between the curved fingertip beams on one sheet are covered by the curved fingertip beams on the adjacent sheet. This ensures that the fluid is sealed securely by the staggered thin metal sheets and the radial contact between the rotor and the fingertip shoe.

[0003] The fingertip plate is 0.3mm thick, and the fingertip beam is 60mm long, forming a slender rod. The fingertip boot is located at the head of the fingertip beam and is susceptible to plastic deformation under stress. The assembled fingertip boot contacts the corresponding area of the engine main shaft, and the surface roughness must be controlled to Ra0.4μm to avoid scratching the main shaft coating.

[0004] Finger boots are prone to deformation under stress, so machining must be performed without introducing machining stress and maintaining a surface roughness of Ra0.4. Direct single-piece machining has yet to find an effective solution. The current solution involves stacking multiple fingertip raw materials together and then wire-cutting the fingertip grooves and inner rings to create the fingertip boots. However, EDM machining often leaves a residual recast layer on the fingertip boots.

[0005] Therefore, the inventor provides a non-contact electrolytic trimming method and fixture for the cantilever beam boot portion of a fingertip piece. Summary of the Invention

[0006] (1) Technical problems to be solved

[0007] The embodiment of the present invention provides a non-contact electrolytic trimming method and fixture for the cantilever beam boot portion of a fingertip piece, which solves the technical problems of how to improve the surface quality of the fingertip structure and ensure reliable sealing.

[0008] (2) Technical solution

[0009] The present invention provides a non-contact electrolytic trimming method for a cantilever beam boot portion of a fingertip sheet, comprising the following steps:

[0010] Multiple fingertip pieces are staggered and stacked on the lower pressing piece and the upper pressing piece is installed. The fingertip boots on the stacked fingertip pieces are trimmed and installed in the inner cavity of the fixture base to achieve double positioning of the grouped fingertip pieces.

[0011] Fix the fingertip groups, install ceramic bearings and electrodes, and connect the power supply and electrolyte conduit;

[0012] introducing the electrolyte in the electrolyte conduit into the processing area through the electrode;

[0013] Driving the electrode to rotate at a set angular velocity, and turning on the power supply when the speed enters a stable range;

[0014] A set voltage is applied to the electrodes to perform non-contact electrolytic polishing on the fingertip boots superimposed on the fingertip sheet.

[0015] Furthermore, the fingertip boots for trimming the laminated fingertip pieces are specifically:

[0016] The high point area of the fingertip boot is first removed until it is on the same plane as the other metal surfaces.

[0017] Furthermore, the double over-positioning of the grouped fingertip pieces is achieved by:

[0018] The rotation center of the engine main shaft and the rotation axis determined by the pin shafts of the positioning pins of the multiple fingertips are the same axis; and the cylindrical outer circle formed by the superposition of the multiple fingertips matches the fingertip piece mounting seat of the engine.

[0019] Furthermore, when the angular velocity of the electrode enters the rotation speed stable range, its rotation direction is consistent with the rotation direction of the fingertip boot.

[0020] Furthermore, the set voltage is 25V to 30V.

[0021] Furthermore, the applying of a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots on the superimposed fingertip sheet is specifically as follows:

[0022] A processing gap is reserved between the side surface of the electrode and the inner circle of the fingertip sheet.

[0023] Furthermore, the processing gap is 0.5 mm to 1.0 mm.

[0024] Furthermore, after applying a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots on the superimposed fingertip sheet, the method further includes:

[0025] The polished fingertip sheet, the upper pressing sheet, and the lower pressing sheet are cleaned and sealed for storage.

[0026] Furthermore, the polished fingertip sheet, the upper pressing sheet, and the lower pressing sheet are cleaned and sealed for storage, specifically:

[0027] The polished fingertip sheet, together with the upper pressing sheet and the lower pressing sheet, is ultrasonically cleaned in clean water and then cleaned in clean kerosene. The upper pressing sheet and the lower pressing sheet are removed, and the fingertip sheet is vacuum-sealed for storage.

[0028] The present invention also provides a non-contact electrolytic dressing fixture for the cantilever beam boot of a fingertip piece, comprising an electrode, a positioning pin, a Z-shaped pressing block, an upper pressing piece, a lower pressing piece, a fixture base, an electrode insulating block and a ceramic bearing; wherein,

[0029] The plurality of positioning pins are distributed along the circumference of the fixture base and are used to position the grouped fingertip pieces. The lower pressing piece is placed on the fixture base and is used to support the grouped fingertip pieces. The upper pressing piece is attached to the lower pressing piece and is used to compact the grouped fingertip pieces. The Z-shaped pressing block is used to press the upper pressing piece. The electrode insulating block is provided at the contact position between the electrode and the grouped fingertip pieces. The ceramic bearing is coaxially mounted on the fixture base and is used to connect to the electrode.

[0030] (3) Beneficial effects

[0031] In summary, during the electrolytic machining process, the present invention dissolves the metal at the high point of the fingertip boot first under the action of the electric field and electrolyte, thereby improving the surface roughness of the machining area; at the same time, the electrolytic machining is non-contact and will not introduce contact stress and thermal processing stress, thereby controlling the deformation of the elastic cantilever fingertip beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0033] Figure 1 This is a schematic flow chart of a non-contact electrolytic trimming method for a cantilever beam boot portion of a fingertip sheet provided by an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the principle of non-contact electrolytic trimming of the cantilever beam boot portion of a fingertip sheet provided by an embodiment of the present invention;

[0035] Figure 3 This is a schematic structural diagram of a double over-positioning assembly of a group of fingertip pieces provided by an embodiment of the present invention;

[0036] Figure 4 This is a schematic structural diagram of a processing gap for trimming a group of fingertip slices provided by an embodiment of the present invention;

[0037] Figure 5Schematic diagram of the structure of a non-contact electrolytic dressing fixture for a cantilever beam boot portion of a fingertip provided by an embodiment of the present invention;

[0038] Figure 6 It is a schematic diagram of the structural flip of a non-contact electrolytic trimming fixture for the cantilever beam boot portion of a fingertip sheet provided by an embodiment of the present invention.

[0039] In the picture:

[0040] 1-electrode; 2-locating pin; 3-pressing block; 4-upper pressing plate; 5-grouped fingertip plate; 6-lower pressing plate; 7-clamp base; 8-electrode insulating block; 9-ceramic bearing. DETAILED DESCRIPTION

[0041] The following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are intended to illustrate the principles of the present invention and are not intended to limit the scope of the present invention. That is, the present invention is not limited to the described embodiments and covers any modifications, replacements, and improvements to the parts, components, and connection methods without departing from the spirit of the present invention.

[0042] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the products of the present invention are conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. These are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they should not be understood as limitations on the present invention.

[0044] It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "disposed" and "installed" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0045] Figure 1 1 is a flow chart of a non-contact electrolytic trimming method for a cantilever beam boot portion of a fingertip provided by an embodiment of the present invention. The method may include the following steps:

[0046] S100, staggering and stacking a plurality of fingertip sheets on a lower pressing sheet and installing an upper pressing sheet, trimming the fingertip boots on the stacked fingertip sheets, and installing them in the inner cavity of the fixture base to achieve double positioning of the grouped fingertip sheets;

[0047] S200, fixing the group of fingertip pieces, installing ceramic bearings and electrodes, and connecting a power supply and an electrolyte conduit;

[0048] S300, introducing the electrolyte in the electrolyte conduit into the processing area through the electrode;

[0049] S400, driving the electrode to rotate at a set angular velocity, and turning on the power supply when the speed enters a stable range;

[0050] S500 , applying a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots superimposed on the fingertip sheet.

[0051] In the above embodiment, the electrode is connected to the negative pole of the power supply, and the fingertip is connected to the positive pole of the power supply. The interior of the electrode is hollow, and the electrolyte flows into the middle of the electrode and out through the outlet, and is introduced into the processing area (entering the gap between the electrode and the fingertip), which is a positive water processing method. Figure 2 As shown in the figure, the electrode rotates under the drive of the Z axis. After entering the stable speed area, the electrode rotation direction should be consistent with the rotation direction of the fingertip boot, and voltage should be applied.

[0052] During electrochemical machining, the metal at the high points of the fingertip boot is first dissolved by the electric field and electrolyte, and then circulated out with the electrolyte. The high points of the fingertip boot are first machined to a level with the rest of the metal surface, improving surface roughness. Furthermore, electrochemical machining is non-contact, eliminating contact and thermal stresses and limiting deformation of the elastic cantilever fingertip beam.

[0053] As an optional implementation, in step S100, the fingertip boot with the laminated fingertip sheet is trimmed, specifically by first removing the high point area of the fingertip boot until it is on the same plane as other metal surfaces.

[0054] Among them, the above embodiment provides a specific method for trimming the fingertip boots to achieve synchronous electrolytic processing of the electrodes on the fingertip boots.

[0055] As an optional embodiment, in step S100, double positioning of the grouped fingertip pieces is achieved, specifically: the rotation center of the engine main shaft and the rotation axis of multiple fingertip pieces determined by the pin shaft of the positioning pin are the same axis; and the cylindrical outer circle formed by the superposition of multiple fingertip pieces cooperates with the fingertip piece mounting seat of the engine.

[0056] Specifically, the fingertip pieces are staggered and stacked together, and usually the fingertip pieces are assembled in multiples of 6 (such as 6 pieces, 12 pieces or 18 pieces, etc.). Relying on the positioning pin holes and outer edge positioning of the fingertip pieces, double positioning is performed to ensure that the fingertip pieces can be smoothly installed in the engine while improving the rigidity of the fingertip pieces. The first positioning: 5 positioning pins in an evenly distributed array constitute the rotation center of the engine main shaft; the rotation axis of multiple fingertip pieces determined by 5 φ2 pin shafts is the same axis. The second positioning: the outer circle of the cylinder formed by the superposition of multiple fingertip pieces needs to match the fingertip piece mounting seat of the engine to meet the requirements of φ329H7 / g6, such as Figure 3 shown.

[0057] The first stage of positioning ensures that each suspended fingertip shoe is positioned accurately within the stacked layers, forming the "fingertip inner column" with precise positioning. This allows the "fingertip inner column" to be trimmed to a high degree of cylindricity, and finally installed into the engine, securing the engine's side and providing a stronger gas seal. The second stage of positioning, where the multiple fingertip pieces are stacked together to form an "external cylindrical surface," creates a relatively tight fit with the mounting base, significantly improving the rigidity of the assembled fingertip piece and facilitating processing and assembly.

[0058] As an optional embodiment, when the angular velocity of the electrode enters the rotation speed stable range, its rotation direction is consistent with the rotation direction of the fingertip boot. Specifically, the rotation direction of the electrode is the same as that of the fingertip boot.

[0059] As an optional implementation, the voltage is set to 25 V to 30 V. This voltage value is an optimal parameter obtained through actual experiments.

[0060] As an optional embodiment, in step S500, a set voltage is applied to the electrode to perform non-contact electrolytic polishing on the fingertip boots on the superimposed fingertip sheet, specifically: a processing gap is reserved between the side of the electrode and the inner circle of the fingertip sheet.

[0061] In the above embodiment, the electrode is connected to the fixture base through a ceramic bearing, and the ceramic bearing has insulation and anti-corrosion effects. The rotation center of the electrode coincides with the center of the grouped fingertip pieces, and a processing gap is reserved between the side of the electrode and the inner circle of the fingertip piece. The processing gap Δ is controlled at 0.5 to 1.0 mm (within this range, non-contact electrolytic processing can be satisfied. A distance that is too large will affect the electrolytic processing effect, and a distance that is too small will introduce contact stress and thermal processing stress). Install the upper pressing piece of the fingertip piece, and the Z-shaped pressing block applies pressure along the Z-axis direction of the fingertip piece to clamp the fingertip piece, while increasing the friction between the fingertips of the fingertip beam, thereby improving the overall rigidity of the fingertip beam and resisting the impact of the electrolyte. Figure 4 shown.

[0062] As an optional embodiment, after step S500, applying a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots on the superimposed fingertip sheet, the method further includes:

[0063] Step S600: Clean the polished fingertip sheet together with the upper pressing sheet and the lower pressing sheet and then seal and store them.

[0064] As an optional implementation, in step S600, the polished fingertip sheet, together with the upper pressing sheet and the lower pressing sheet, is cleaned and sealed for storage. Specifically, the polished fingertip sheet, together with the upper pressing sheet and the lower pressing sheet, is ultrasonically cleaned in clean water, then cleaned in clean kerosene, the upper pressing sheet and the lower pressing sheet are removed, and the fingertip sheet is vacuum-sealed for storage.

[0065] Figure 5 Schematic diagram of the structure of a non-contact electrolytic trimming fixture for the cantilever beam boot portion of a fingertip provided by an embodiment of the present invention, such as Figure 5-6 As shown, it includes an electrode 1, a positioning pin 2, a Z-shaped pressing block 3, an upper pressing plate 4, a lower pressing plate 6, a clamp base 7, an electrode insulating block 8 and a ceramic bearing 9; wherein,

[0066] Multiple positioning pins 2 are distributed along the circumference of the fixture base 7 and are used to position the grouped fingertip pieces 5. The lower pressing piece 6 is placed on the fixture base 7 and is used to support the grouped fingertip pieces 5. The upper pressing piece 4 is attached to the lower pressing piece 6 and is used to compact the grouped fingertip pieces 5. The Z-shaped pressing block 3 is used to press the upper pressing piece 4. The electrode insulating block 8 is arranged at the contact position between the electrode 1 and the grouped fingertip pieces 5. The ceramic bearing 9 is coaxially installed on the fixture base 7 and is used to connect with the electrode 1.

[0067] Example 1

[0068] The present invention takes the outer diameter of the fingertip sheet of φ320, the inner ring of the fingertip shoe is uniformly arrayed to form a diameter of φ298.5, the material is GH3230, and 6 pieces are polished in groups to the inner ring to Ra0.4μm as an example. The non-contact electrolytic finishing process is as follows:

[0069] (1) Place the pressing sheet horizontally on the platform, insert 5 φ2 positioning pins, and install the 6 fingertip pieces on the lower pressing sheet in an interlaced manner according to the 5 pin holes. Install the upper pressing sheet, trim the "columnar" outer edge of the stacked fingertip pieces, and install them in the inner cavity of the fixture base (the processing size is φ329H7), thus realizing the double positioning installation of the group of fingertip pieces.

[0070] (2) According to the fixture drawing, fix the fingertip pieces into groups, install the ceramic bearings, electrodes, connect the power supply, and electrolyte conduit;

[0071] (3) Turn on the switch of the infusion system and introduce the NaNO3 solution into the processing area through the electrode;

[0072] (4) The electrode rotates at a speed of 600 r / min driven by the Z axis of the machine tool. When the electrode enters the stable speed range, the power is turned on.

[0073] (5) Turn on the power supply and apply a constant processing voltage of 30V; after 1 minute, turn off the power supply to complete the superimposed fingertip boot polishing;

[0074] (6) Remove the six polished fingertips, along with the upper and lower supports, from the fixture base. Ultrasonic clean them in clean water for 30 minutes, then clean them in clean kerosene for 20 minutes. Remove the upper and lower supports, place them in a dedicated packaging box, and vacuum seal them for storage.

[0075] The electrolytic trimming of the present invention can achieve the combined trimming of 6 to 18 fingertip boots at a time, thereby improving processing efficiency and reducing processing costs, simulating the initial running-in of the fingertip pieces in actual use, and promoting the fingertip pieces to enter a stable wear period.

[0076] It should be noted that the various embodiments in this specification are described in a progressive manner. References to the same or similar parts between the various embodiments are sufficient. Each embodiment focuses on the differences from the other embodiments. The present invention is not limited to the specific steps and structures described above and shown in the figures. Furthermore, for the sake of brevity, detailed descriptions of known methods and technologies are omitted here.

[0077] The above are merely embodiments of the present application and are not intended to limit the present application. Various modifications and variations are possible for those skilled in the art without departing from the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included within the scope of the claims of the present application.

Claims

1. A non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet, characterized in that: The method comprises the following steps: Multiple fingertip pieces are staggered and stacked on the lower pressing piece and the upper pressing piece is installed. The fingertip boots on the stacked fingertip pieces are trimmed and installed in the inner cavity of the fixture base to achieve double positioning of the grouped fingertip pieces. Fix the fingertip groups, install ceramic bearings and electrodes, and connect the power supply and electrolyte conduit; introducing the electrolyte in the electrolyte conduit into the processing area through the electrode; Driving the electrode to rotate at a set angular velocity, and turning on the power supply when the speed enters a stable range; applying a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots on the superimposed fingertip sheet; The fixture comprises a positioning pin (2), a Z-shaped pressing block (3), an upper pressing plate (4), a lower pressing plate (6), a fixture base (7), an electrode insulating block (8) and a ceramic bearing (9); wherein, A plurality of positioning pins (2) are distributed along the circumference of the fixture base (7) and are used to position the grouped fingertip pieces (5); the lower pressing piece (6) is placed on the fixture base (7) and is used to carry the grouped fingertip pieces (5); the upper pressing piece (4) is attached to the lower pressing piece (6) and is used to compact the grouped fingertip pieces (5); the Z-shaped pressing block (3) is used to compact the upper pressing piece (4); the electrode insulating block (8) is provided at the contact position between the electrode (1) and the grouped fingertip pieces (5); the ceramic bearing (9) is coaxially mounted on the fixture base (7) and is used to connect with the electrode (1); The double over-positioning of the grouped fingertip pieces is achieved by: The rotation center of the engine main shaft and the rotation axis determined by the pin shafts of the positioning pins of the multiple fingertips are the same axis; and the cylindrical outer circle formed by the superposition of the multiple fingertips matches the fingertip piece mounting seat of the engine.

2. The non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet according to claim 1, characterized in that: The fingertip boots for trimming the laminated fingertip pieces are specifically: The high point area of the fingertip boot is first removed until it is on the same plane as the other metal surfaces.

3. The non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet according to claim 1, characterized in that: When the angular velocity of the electrode enters a stable rotation speed range, its rotation direction is consistent with the rotation direction of the fingertip boot.

4. The non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet according to claim 1, characterized in that: The set voltage is 25V to 30V.

5. The non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet according to claim 1, characterized in that: The step of applying a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots on the superimposed fingertip sheet is specifically as follows: A processing gap is reserved between the side surface of the electrode and the inner circle of the fingertip sheet.

6. The non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet according to claim 5, characterized in that: The processing gap is 0.5mm to 1.0mm.

7. The non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet according to claim 1, characterized in that: After applying a set voltage to the electrodes to perform non-contact electrolytic polishing on the fingertip boots on the superimposed fingertip sheet, the method further includes: The polished fingertip sheet, the upper pressing sheet, and the lower pressing sheet are cleaned and sealed for storage.

8. The non-contact electrolytic trimming method for the cantilever beam boot portion of a fingertip sheet according to claim 7, characterized in that: The polished fingertip sheet, the upper pressing sheet, and the lower pressing sheet are cleaned and sealed for storage, specifically: The polished fingertip sheet, together with the upper pressing sheet and the lower pressing sheet, is ultrasonically cleaned in clean water and then cleaned in clean kerosene. The upper pressing sheet and the lower pressing sheet are removed, and the fingertip sheet is vacuum-sealed for storage.

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