Device and method for electrochemical machining of sleeve-shaped components with closed flow field at the inlet and exhaust edges

Abstract

The present invention relates to a sleeve-shaped electrolytic machining device and method for a centripetal component with a closed flow field on the inlet and exhaust sides, and belongs to the field of electrolytic machining. The device includes a liquid sealing baffle, a cathode body, a connecting shaft, a compression spring, a liquid inlet base and a fixed bracket. The liquid sealing baffle is respectively tightly attached to the side end faces of the inlet and exhaust sides of the cathode body, and a connecting shaft is provided at the tail end of the baffle, which respectively cooperates with the fixed bracket through the shaft hole gap to form a sliding pair. A compression spring is provided on the outer sleeve of the connecting shaft, so that the liquid sealing baffle is always tightly attached to the inner wall of the centripetal component under the pressure of the compression spring. The present invention increases the outlet back pressure of the inlet and exhaust sides, so that the electrolyte flows out from the blade basin and the back side of the blade, reduces the liquid outlet area of ​​the processing area, increases the electrolyte flow rate, and thus improves the processing stability of the centripetal component. In addition, the device does not need to be repeatedly disassembled and clamped during the processing process, and can achieve a continuous and stable liquid sealing effect of the blade, thereby improving the processing efficiency of the centripetal component.

Description

Technical Field

[0001] The invention relates to a sleeve-shaped electrolytic machining device and method for a centripetal component with a closed flow field at the intake and exhaust edges, belonging to the field of electrolytic machining. Background Art

[0002] Electrochemical machining (ECM) is a non-traditional machining technique based on the principle of electrochemical anodic material removal. It offers advantages such as no tool wear, low cost, and freedom from material mechanical property limitations. Sleeve ECM involves removing excess material around the desired workpiece surface through the cathode. This method offers single-step workpiece formation, high machining efficiency, and the ability to enable mass production. It is suitable for machining integral components with straight-grained surfaces, such as aerospace engine diffusers and centripetal components.

[0003] As a key component in aerospace engines, centripetal structures are characterized by a large number of densely packed blades and a confined disk space. These structures integrate the blades with a thin-walled casing. The leading and trailing edges of the centripetal blades have large curvatures and limited openness, resulting in poor electrolyte accessibility. This reduces flow uniformity in the machining area and can easily lead to machining shorts at the blade intake and exhaust edges. The high number and density of the blades, the narrow passageways between adjacent blades, and the limited disk space make the machining of centripetal structures even more challenging.

[0004] Building on this, researchers have developed the patent "Device and Method for Electrolytic Machining of Integral Blades with Full-Profile Liquid Supply" (Application No. CN202010730223.9, Inventors Zhu Dong, Guo Jianwei, and Zhu Di). This approach employs separate liquid inlets to supply electrolyte to the blade base, back, intake, and exhaust edges of the blade, creating a closed flow pattern with independently controlled electrolyte within each flow channel. This improves flow uniformity in the machining area, enhances machining stability and repeatability of the intake and exhaust edges, and enables full-profile machining of the integral blade. In the patent "Device and Method for Electrolytic Machining of Composite Fluid Insulated Blade Jacketing" (Application No. CN202211180503.2, Inventors Tao Jinren, Wanfei, Xu Jinkai, Sun Huihui, and Deng Haoran), low-temperature, low-conductivity deionized water is combined with post-processing stray electrolyte to reduce the conductivity and temperature of the stray electrolyte in the machined area, thereby suppressing stray corrosion and reducing blade taper and improving blade machining quality.

[0005] Currently, sleeve electrochemical machining (ECM) mostly uses a traditional full-contour liquid supply flow field, introducing a cantilevered insulating sleeve to optimize the flow channel structure and improve flow field uniformity. However, the electrolyte remains diffuse near the exit of the machining area, especially near the inlet and exhaust edges of complex-profile blades, where processing short-circuits caused by localized liquid shortages are prone to occur. Existing devices and methods struggle to address this problem of localized liquid shortages at the inlet and exhaust edges of complex-profile blades. A new sleeve electrochemical machining device and method is needed to optimize the flow field structure at the inlet and exhaust exits, improve the flow field uniformity in the machining area, and enhance machining stability. Summary of the Invention

[0006] This invention proposes a sleeve-shaped electrolytic machining device and method for centripetal component inlet and outlet edges with a closed flow field. This method increases the outlet back pressure at the inlet and outlet edges, allowing the electrolyte to flow out from the blade basin and backside. This reduces the liquid outlet area in the machining zone, increases the electrolyte flow rate, and thus improves the machining stability of the centripetal component. Furthermore, this device eliminates the need for repeated disassembly and re-clamping during machining, achieving continuous and stable blade sealing and improving the machining efficiency of the centripetal component.

[0007] A sleeve-shaped electrolytic machining device with a closed flow field on the inlet and exhaust sides of a centripetal component is used for machining the centripetal blades of the centripetal component. The centripetal component is composed of a centripetal blade and a thin-walled casing. The centripetal blade is located on the inner side of the component, from the root to the tip of the blade toward the center of the component. It is characterized in that: the device includes a fixed bracket, a liquid inlet base, a liquid sealing baffle and a cathode body; the first end of the fixed bracket is connected to the main shaft of the machine tool, and the second end is used to install the liquid sealing baffle and the cathode body; the liquid sealing baffle is composed of an inlet side liquid sealing baffle and an exhaust side liquid sealing baffle; the two are symmetrical up and down, and are respectively tightly attached to the inlet and exhaust side end faces of the cathode body; both are "U"-shaped, and the end of the "U"-shaped structure is in an arc shape, and its arc radius is equal to the radius of the inner wall of the centripetal component, and the tails of the two "U"-shaped structures are connected and integrated; the "U"-shaped structure of the inlet side liquid sealing baffle and the exhaust side liquid sealing baffle An inner hole is provided at the tail of the structure; a bracket shaft hole is provided on the inner side of the second end of the fixed bracket at the corresponding position of the inner hole of the baffle tail; a connecting shaft is installed between the inner hole of the baffle tail and the corresponding bracket shaft hole, one end of the connecting shaft is installed in the inner hole of the baffle tail through a countersunk bolt, and the other end passes through the bracket shaft hole through a clearance fit, and can slide in the bracket shaft hole, and a compression spring is sleeved on the outer wall of the connecting shaft; the liquid inlet base is flange-shaped, and a liquid inlet hole is provided at the tail, which can pass the electrolyte, and the liquid inlet base is connected to the second end of the fixed bracket; the inner contour of the cathode body cavity is larger than the blade contour, and the tail fixed end is connected to the liquid inlet base.

[0008] The method for electrolytic machining of a sleeve-shaped closed flow field at the inlet and exhaust edges of a centripetal component is characterized by comprising the following processes: before machining begins, the liquid-sealing baffle is not in contact with the inner wall of the centripetal component, and the distance between the end face of the cathode body and the end face of the blade blank has not reached the initial machining gap; driven by the machine tool spindle, the cathode body, the liquid-sealing baffle and the fixed bracket are fed radially, approaching the centripetal component until the liquid-sealing baffle is in close contact with the inner wall of the centripetal component; at this time, the liquid-sealing baffle no longer moves, and the cathode body continues to move toward the blade blank until the initial machining gap is reached; in this process, the free end of the connecting shaft slides in the bracket shaft hole of the fixed bracket, compressing the spring The spring is compressed and deformed; during the processing, the cathode body is continuously fed, the compression spring is continuously compressed and deformed, and the centripetal blades are gradually formed under the action of electrolysis; at this time, the liquid sealing baffle is always kept close to the inner wall of the centripetal component under the pressure of the compression spring and remains stationary to achieve the effect of stable liquid sealing; after the processing is completed, the cathode body returns to the initial processing position, the compression spring rebounds, and the liquid sealing baffle remains stationary; the processed blades are protected with an insulating sleeve; the centripetal component is rotated, where the rotation angle is 360 / N, N represents the number of centripetal blades, and N is a positive integer greater than 1; repeat the above steps to process the next centripetal blade.

[0009] The aforementioned centripetal component inlet and exhaust edge sealed flow field sleeve electrochemical machining device is characterized in that the U-shaped structure of the inlet and exhaust edge sealing baffles each has one rear end inner hole, and the two holes are arranged diagonally. This means that only two sets of connecting shafts are provided, avoiding the problem of multiple sets of connecting shafts causing poor sliding in the bracket shaft hole.

[0010] The aforementioned sleeve-shaped electrochemical machining device with a closed flow field at the inlet and exhaust edges of a centripetal member is characterized in that the length of the compression spring is greater than the axial distance between the liquid sealing baffle and the fixed bracket, so as to ensure that the compression spring and the device can function normally.

[0011] The beneficial effects of the present invention are:

[0012] The present invention utilizes a closed flow field at the inlet and exhaust edges, facilitating the shaping of the blade's inlet and exhaust edges. The large curvature and limited openness of the blade's inlet and exhaust edges result in poor electrolyte accessibility, reducing blade processing stability. The closed flow field at the inlet and exhaust edges compensates for the uncontrollable flow field at the outlet of the inlet and exhaust edges, a drawback of existing full-contour liquid supply methods. This improves flow field stability at the inlet and exhaust edges and facilitates enhanced processing precision for the blade's inlet and exhaust edges.

[0013] A liquid-sealing baffle is designed, positioned closely against the cathode head's inlet and exhaust edges. This increases the back pressure at these outlets, obstructing the electrolyte flow from the blade's inlet and exhaust edges, forcing it to flow more from the blade basin and backside. While maintaining the same inlet flow rate, this reduces the outlet area of ​​the processing zone, increasing the electrolyte flow rate and rapidly removing electrolysis products. This improves machining stability and, consequently, efficiency, for centripetal components.

[0014] The present invention adopts a combined liquid sealing device, which can achieve real-time and stable liquid sealing of the processing area and improve the clamping efficiency of the centripetal component. Driven by the main shaft of the machine tool, the cathode body is continuously fed to complete the processing of the centripetal blades. The liquid sealing baffle is always close to the inner wall of the centripetal component under the pressure of the compression spring, so that the flow field in the processing area is closed. After the processing is completed, the compression spring is reset, and the cathode and baffle return to the initial processing position. This process does not require repeated disassembly and clamping, and can achieve a continuous and stable liquid sealing effect on the blades, which is beneficial to improving the processing efficiency of the centripetal component. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the structural assembly diagram of the sleeve-shaped electrochemical machining device with closed flow field on the inlet and exhaust edges of the centripetal component;

[0016] Figure 2 A schematic diagram of the feed of a sleeve-shaped electrochemical machining device with a closed flow field on the inlet and exhaust edges of a centripetal component (top view);

[0017] Reference numerals in the figure: 1. Centripetal member; 2. Liquid-sealing baffle; 2-1. Liquid-sealing baffle on the air inlet side; 2-2. Liquid-sealing baffle on the exhaust side; 3. Cathode body; 4. Connecting shaft; 5. Compression spring; 6. Liquid-inlet base; 7. Fixed bracket. DETAILED DESCRIPTION

[0018] The following is combined with Figure 1 、 2 The electrolytic machining process of the present invention is described as follows:

[0019] Step 1: Install the centripetal component blank on the electrolytic machining machine, and connect the workpiece to the positive pole of the power supply;

[0020] Step 2: Connect the fixed bracket to the machine tool spindle, and the spindle to the negative pole of the power supply. The liquid sealing baffle is matched with the fixed bracket through the connecting shaft and compression spring to form a shaft hole clearance. The connecting shaft can slide freely in the hole. The side faces of the cathode body inlet and exhaust are tightly attached to the liquid sealing baffle and can slide. The tail of the cathode body and the liquid inlet base are installed on the fixed bracket with bolts and pins;

[0021] Step 3: Start the electrochemical machining machine, drive the spindle, and perform tool setting. Feed the cathode body to the initial machining position. At this time, the connecting shaft slides in the fixed bracket hole, the compression spring begins to be compressed, and the end face of the liquid sealing baffle is pressed against the inner wall of the centripetal component blank.

[0022] Step 4: Start the electrolyte circulation system, and the high-voltage electrolyte flows into the cathode body through the liquid inlet base to supply liquid to the processing area;

[0023] Step 5: Start the electrolytic machining power supply and energize the cathode body and the centripetal component blank;

[0024] Step 6: Start the machine tool feed program and begin processing. The cathode body is fed under the drive of the fixed bracket, and the electrolyte flows through the processing gap to carry away the electrolysis products. The sealing baffle remains stationary under the pressure of the compression spring, and always applies back pressure to the inlet and exhaust side outlets to increase the electrolyte flow rate;

[0025] Step 7: When processing is complete, turn off the power supply and the electrolyte circulation system. Return the cathode to its initial processing position. The compressed spring will rebound, and the liquid sealing baffle will remain stationary. Rotate the centripetal component to the next station and repeat steps 4 to 7 until the centripetal component is fully processed.

Claims

1. A sleeve-shaped electrochemical machining device for a centripetal component with a closed flow field at the inlet and exhaust edges, used for machining centripetal blades of a centripetal component (1), wherein the centripetal component (1) is composed of a centripetal blade and a thin-walled casing, wherein the centripetal blade is located inside the centripetal component, from the blade root to the blade tip toward the center of the centripetal component; characterized in that: The device comprises a fixed bracket (7), a liquid inlet base (6), a liquid sealing baffle (2) and a cathode body (3); The first end of the fixed bracket (7) is connected to the main shaft of the machine tool, and the second end is used to install the liquid sealing baffle (2) and the cathode body (3); The above-mentioned liquid sealing baffle (2) is composed of an air inlet side liquid sealing baffle (2-1) and an exhaust side liquid sealing baffle (2-2); the two are symmetrical in upper and lower directions and are respectively closely attached to the inlet and exhaust side end faces of the cathode body (3); both are "U"-shaped, and the end of the "U"-shaped structure is in an arc shape, the radius of the arc surface is equal to the radius of the inner wall of the centripetal component (1), and the tail ends of the two "U"-shaped structures are connected and integrated; The tail of the "U"-shaped structure of the air inlet side sealing liquid baffle (2-1) and the air outlet side sealing liquid baffle (2-2) is provided with an inner hole; A bracket shaft hole is provided on the inner side of the second end of the fixing bracket (7) at a position corresponding to the inner hole of the tail portion of the baffle; A connecting shaft (4) is installed between the inner hole of the tail of the sealing baffle (2) and the corresponding bracket shaft hole. One end of the connecting shaft (4) is installed in the inner hole of the tail of the baffle through a countersunk bolt, and the other end passes through the bracket shaft hole through a clearance fit and can slide in the bracket shaft hole. The outer wall of the connecting shaft (4) is covered with a compression spring (5). The liquid inlet base (6) is flange-shaped, and a liquid inlet hole is provided at the tail end thereof, through which the electrolyte can be introduced. The liquid inlet base (6) is connected to the second end of the fixed bracket (7); The inner contour of the cavity of the cathode body (3) is larger than the contour of the blade, and the tail fixed end is connected to the liquid inlet base (6).

2. The sleeve-shaped electrochemical machining device with closed flow field at the inlet and exhaust edges of a centripetal component according to claim 1, characterized in that: The U-shaped structures of the air intake side sealing liquid baffle (2-1) and the air exhaust side sealing liquid baffle (2-2) are each provided with one baffle tail inner hole, and the two holes are provided in a diagonal direction.

3. The sleeve-shaped electrochemical machining device with closed flow field at the inlet and exhaust edges of a centripetal component according to claim 1, characterized in that: The length of the compression spring (5) is greater than the axial distance between the liquid sealing baffle (2) and the fixed bracket (7).

4. A processing method using the centripetal component inlet and exhaust edge closed flow field sleeve electrochemical processing device according to claim 1, characterized in that The following processes are included: Before the start of processing, the liquid sealing baffle (2) does not contact the inner wall of the centripetal component (1), and the distance between the end face of the cathode body (3) and the end face of the blade blank does not reach the initial processing gap; under the drive of the machine tool spindle, the cathode body (3), the liquid sealing baffle (2) and the fixed bracket (7) are fed radially and approach the centripetal component (1) until the liquid sealing baffle (2) and the inner wall of the centripetal component (1) are tightly attached; at this time, the liquid sealing baffle (2) no longer moves, and the cathode body (3) continues to move toward the blade blank until the initial processing gap is reached; in this process, the free end of the connecting shaft (4) slides in the bracket shaft hole of the fixed bracket (7), and the compression spring (5) is compressed and deformed; During the processing, the cathode body (3) is continuously fed, the compression spring (5) continues to be compressed and deformed, and the centripetal blades are gradually formed under the action of electrolysis; at this time, the sealing baffle (2) is always pressed against the inner wall of the centripetal component (1) under the pressure of the compression spring (5) and remains stationary, so as to achieve a stable sealing effect; After the processing is completed, the cathode body (3) returns to the initial processing position, the compression spring (5) rebounds, and the sealing baffle (2) remains stationary; The processed blades are protected with an insulating sleeve; the centripetal component (1) is rotated, wherein the rotation angle is 360 / N degrees, N represents the number of centripetal blades, and N is a positive integer greater than 1; and the above steps are repeated to process the next centripetal blade.

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