A precision electrolytic forming apparatus and method for auxiliary anode protection involute internal spline

Abstract

This invention discloses a precision electrolytic forming device and method for involute internal splines with auxiliary anode protection. The device includes a workpiece positioning and clamping assembly and a cathode assembly. The workpiece positioning and clamping assembly is fixed on the machine tool base and is equipped with a freely sliding conical slit bushing, which can automatically position the workpiece blank. The cathode assembly is fixed on the machine tool spindle and feeds along the axial direction of the workpiece blank. The assembly is equipped with an auxiliary anode protection cylinder. During processing, the potential of the auxiliary anode protection cylinder is higher than that of the workpiece anode, which can effectively reduce the secondary corrosion of the machined tooth surface by the tool cathode and improve the machining accuracy of the involute internal spline.

Description

Technical Field

[0001] This invention relates to the field of CNC electrolytic machining technology, specifically to a precision electrolytic forming device and method for auxiliary anode protection involute internal spline. Background Technology

[0002] An involute internal spline is a type of irregularly shaped bore part with a uniform cross-section. It has a structure similar to an involute spur gear, but with a thicker tooth root and smaller tooth height compared to a spur gear. Involute internal splines often use hard-to-machine materials with higher hardness, strength, and stiffness, and employ special structures such as thin walls and blind holes. They offer advantages such as good tooth surface contact, high load-bearing capacity, high installation accuracy, lighter weight, and long service life, and are widely used in transmission systems in industries such as aerospace and automotive.

[0003] Electrolytic machining is a machining method based on the principle of electrochemical anodic dissolution to remove excess material from workpieces. It has advantages such as being unrestricted by the mechanical properties of materials, high production efficiency, no cathode loss, no residual stress during machining, and good surface quality. Compared with traditional machining, which suffers from serious tool wear, easy surface scratches, and easy workpiece deformation, it is a more ideal machining method for involute internal splines.

[0004] In the precision electrolytic forming of involute internal splines, the tool cathode can cause secondary corrosion on the machined tooth surfaces, reducing the machining accuracy of the involute internal splines. Currently, existing electrolytic machining methods for internal splines generally employ the addition of an insulating layer to reduce secondary corrosion. This method is effective for internal splines with lower precision requirements, but when the precision requirements are high, it cannot effectively reduce the secondary corrosion of the machined tooth surfaces by the tool cathode, failing to meet the actual machining needs of internal splines. Therefore, it is necessary to research a novel method for protecting the machined tooth surfaces of internal splines to improve the machining accuracy of involute internal splines. Summary of the Invention

[0005] The purpose of this invention may be:

[0006] To overcome the shortcomings of the prior art, the present invention provides a precision electrolytic forming device and method for auxiliary anode protection of involute internal splines, which can realize automatic positioning of workpiece blanks, effectively reduce secondary corrosion of the machined tooth surface by the tool cathode, and improve the machining accuracy and efficiency of involute internal splines.

[0007] The technical solution of this invention is:

[0008] A precision electrolytic forming device for involute internal splines with auxiliary anode protection is characterized in that it includes a workpiece positioning and clamping assembly and a cathode assembly; the workpiece positioning and clamping assembly is fixed on the machine tool base, the cathode assembly is fixed on the machine tool spindle, and the cathode assembly is driven by the machine tool spindle to feed along the axis of the workpiece blank;

[0009] The workpiece positioning and clamping assembly includes an insulating water-sealing cavity, a clamping screw cap, a tapered slit bushing, workpiece hole wall insulation, and a fixture base. The fixture base is fixed on the machine tool base, the workpiece hole wall insulation is fixed on the workpiece blank, the tapered slit bushing is placed in the gap formed between the workpiece blank and the fixture base, the clamping screw cap is fixed on the fixture base by a threaded connection, and the insulating water-sealing cavity is fixed on the clamping screw cap.

[0010] The cathode assembly includes a machine tool spindle chuck, a cathode chuck, a cathode connecting rod, an insulating sealing cylinder, an auxiliary anode protection cylinder, a cathode upper end face conformal insulation, a tool cathode, and a cathode lower end face insulation. The machine tool spindle chuck is fixed to the machine tool spindle, the cathode chuck is fixed to the machine tool spindle chuck, the cathode connecting rod is fixed to the cathode chuck, the auxiliary anode protection cylinder is mounted on the insulating sealing cylinder, the insulating sealing cylinder, the cathode upper end face conformal insulation, and the tool cathode are fixed to the cathode connecting rod, and the cathode lower end face insulation is fixed to the tool cathode.

[0011] Furthermore, the insulating sealing cylinder, the cathode upper end face conformal insulation, and the cathode lower end face insulation are used to cover the surface of the cathode connecting rod and the upper and lower end faces of the tool cathode, respectively.

[0012] Furthermore, an auxiliary anode protection cylinder is provided above the conformal insulation on the upper end face of the cathode, and the auxiliary anode protection cylinder is provided with a terminal block.

[0013] Furthermore, the insulating sealing cylinder is provided with a wire-passing hole and an inner wall groove for laying wires. One end of the wire is connected to the terminal of the auxiliary anode protection cylinder through the wire-passing hole and the inner wall groove, and the other end is connected to the positive terminal of the auxiliary anode power supply.

[0014] Furthermore, the workpiece hole wall insulation is used to cover the non-machined area of ​​the involute spline inner hole.

[0015] Furthermore, the workpiece positioning and clamping assembly is provided with a freely sliding conical slit bushing, which is placed in the gap formed between the workpiece blank and the tooling base. The workpiece blank can be automatically positioned and clamped by tightening the clamping screw cap to press down the conical slit bushing.

[0016] Furthermore, the cathode assembly and the workpiece positioning and clamping assembly together form a closed cavity. The cathode assembly is hollow inside to allow the electrolyte to flow in from the front. The insulating water-sealing cavity is provided with an electrolyte outflow port, from which the electrolyte flows out after the cavity is filled.

[0017] Furthermore, a method for precision electrolytic forming of involute internal splines with auxiliary anode protection is characterized by the following steps:

[0018] Step 1: Fix the machine tool spindle chuck to the machine tool spindle, fix the cathode chuck to the machine tool spindle chuck, and fix the tooling base to the machine tool base;

[0019] Step 2: Connect the wire through the wire hole and the inner wall groove to the terminal block of the auxiliary anode protection cylinder. Install the auxiliary anode protection cylinder on the insulating sealing cylinder. Install the insulating sealing cylinder, the upper end face of the cathode conformal insulation, and the tool cathode on the cathode connecting rod. Install the lower end face of the cathode insulation on the tool cathode.

[0020] Step 3: Install the workpiece hole wall insulation on the workpiece blank, place the workpiece blank on the tooling base, put the tapered slit bushing into the gap formed by the workpiece blank and the tooling base, install the clamping screw cap on the tooling base through threaded connection, and install the insulating water sealing cavity on the clamping screw cap.

[0021] Step 4: Connect the fixture base to the positive terminal of the machine tool, connect the machine tool spindle chuck to the negative terminal of the machine tool, and connect the auxiliary anode protection cylinder to the positive terminal of the auxiliary anode power supply; start the electrolytic machining machine tool, perform pre-fluid flow to check the sealing of the fixture flow channel, and then control the machine tool spindle to perform tool setting;

[0022] Step 5: Set the electrolytic machining process parameters, introduce the electrolyte to start machining. As the machine tool spindle feeds, the involute spline gradually takes shape due to the electrochemical anodic dissolution effect.

[0023] Step Six: After processing is completed, stop the fluid flow, remove the workpiece blank, and shut down the machine tool.

[0024] The advantages of this invention may be:

[0025] This invention adopts a freely sliding conical slit bushing design. After the workpiece blank is placed on the tooling base, the conical slit bushing is placed into the gap formed between the workpiece blank and the tooling base. By tightening the clamping screw cap and pressing down the conical slit bushing, the workpiece blank is automatically positioned and clamped. While ensuring the accurate positioning of the workpiece blank, the clamping efficiency of the workpiece blank is improved.

[0026] This invention achieves involute internal spline forming based on the principle of electrochemical anodic dissolution. Under the premise of ensuring accurate workpiece centering, as long as the manufacturing precision of the tool cathode is met and appropriate processing parameters are selected, the actual processed tooth profile of the workpiece can be made infinitely close to the theoretical profile. Compared with traditional processing methods, higher processing precision and surface quality can be obtained.

[0027] This invention addresses the problem of stray corrosion on both the machined and unmachined surfaces of involute internal splines during electrolytic machining, which reduces forming accuracy. It combines sacrificial auxiliary anode protection and insulation shielding. Firstly, insulating components such as upper and lower cathode end face insulation and workpiece hole wall insulation shield the electric field on the unmachined parts of the involute internal spline, thus suppressing stray corrosion on the unmachined surfaces. Secondly, an auxiliary anode protection cylinder is connected to the machine tool's auxiliary anode power supply, giving it a higher potential than the workpiece anode. This attracts stray electric fields between the tool cathode and the machined tooth surface, effectively reducing secondary corrosion caused by the tool cathode and improving the machining accuracy of the involute internal spline's tooth profile and direction. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the involute internal spline workpiece blank and workpiece according to an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of the structure of a precision electrolytic forming device for auxiliary anode protection involute internal spline according to an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of the precision electrolytic forming process for auxiliary anode protection involute internal splines according to an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of an auxiliary anode protection cylinder according to an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of a tapered slotted bushing according to an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of the auxiliary anode wiring according to an embodiment of the present invention.

[0035] In the diagram: 1. Machine tool spindle chuck; 2. Cathode chuck; 3. Cathode connecting rod; 4. Insulating sealing cylinder.

[0036] 4a. Threading hole; 4b. Inner wall groove; 5. Auxiliary anode protection cylinder; 5a. Terminal post; 6. Cathode upper end face conformal insulation; 7. Tool cathode; 8. Cathode lower end face insulation; 9. Workpiece blank; 10. Insulating water sealing cavity; 11. Tightening screw cap; 12. Conical slit bushing; 13. Workpiece hole wall insulation; 14. Tooling base. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0039] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0040] This invention targets involute internal splines such as Figure 1 As shown, the workpiece blank 9 is a cylindrical thin-walled part. Traditional machining methods are prone to workpiece deformation and surface scratches, which reduce the workpiece forming accuracy and surface quality.

[0041] like Figure 2 As shown, an auxiliary anode protection involute internal spline precision electrolytic forming device includes a workpiece positioning and clamping assembly and a cathode assembly. The workpiece positioning and clamping assembly is fixed on the machine tool base, and the cathode assembly is fixed on the machine tool spindle. The cathode assembly is driven by the machine tool spindle to feed along the axis of the workpiece blank 9.

[0042] The workpiece positioning and clamping assembly includes an insulating water-sealing cavity 10, a clamping screw cap 11, a tapered slit bushing 12, a workpiece hole wall insulation 13, and a fixture base 14. The fixture base 14 is fixed on the machine tool base, the workpiece hole wall insulation 13 is fixed on the workpiece blank 9, the tapered slit bushing 12 is placed in the gap formed between the workpiece blank 9 and the fixture base 14, the clamping screw cap 11 is fixed on the fixture base 14 by a threaded connection, and the insulating water-sealing cavity 10 is fixed on the clamping screw cap 11.

[0043] The cathode assembly includes a machine tool spindle chuck 1, a cathode chuck 2, a cathode connecting rod 3, an insulating sealing cylinder 4, an auxiliary anode protection cylinder 5, a cathode upper end face conformal insulator 6, a tool cathode 7, and a cathode lower end face insulator 8. The machine tool spindle chuck 1 is fixed to the machine tool spindle, the cathode chuck 2 is fixed to the machine tool spindle chuck 1, the cathode connecting rod 3 is fixed to the cathode chuck 2, the auxiliary anode protection cylinder 5 is mounted on the insulating sealing cylinder 4, the insulating sealing cylinder 4, the cathode upper end face conformal insulator 6, and the tool cathode 7 are fixed to the cathode connecting rod 3, and the cathode lower end face insulator 8 is fixed to the tool cathode 7.

[0044] like Figure 3 As shown, the insulating sealing cylinder 4, the cathode upper end face conformal insulation 6, and the cathode lower end face insulation 8 are used to cover the surface of the cathode connecting rod 3 and the upper and lower end faces of the tool cathode 7, respectively.

[0045] like Figure 3 , 4 As shown in Figure 6, an auxiliary anode protection cylinder 5 is provided above the cathode upper end face conformal insulation 6. The auxiliary anode protection cylinder 5 is provided with a terminal 5a. The insulating sealing cylinder 4 is provided with a wire-passing hole 4a and an inner wall groove 4b. One end of the wire is connected to the terminal 5a of the auxiliary anode protection cylinder 5 through the wire-passing hole 4a and the inner wall groove 4b, and the other end is connected to the positive terminal of the auxiliary anode power supply. The workpiece hole wall insulation 13 protects the non-machined area of ​​the inner hole of the workpiece blank 9 by insulating cover. The auxiliary anode protection cylinder 5 has a higher potential than the workpiece anode. During machining, the secondary corrosion of the machined tooth surface by the tool cathode 7 is effectively reduced by the method of insulating protection and sacrificing the auxiliary anode to regulate the electric field, thereby improving the machining accuracy of the involute spline.

[0046] The cathode assembly and the workpiece positioning and clamping assembly together form a closed cavity. The cathode assembly is hollow inside to allow the electrolyte to flow in from the front. The upper insulating water-sealing cavity 10 is provided with an electrolyte outflow port, from which the electrolyte flows out after the cavity is filled.

[0047] like Figure 3 , 5 As shown, the workpiece positioning and clamping assembly is provided with a freely sliding conical slit bushing 12. After the workpiece blank 9 is placed on the tooling base 14, it is placed in the gap formed between the workpiece blank 9 and the tooling base 14. Tightening the clamping screw cap 11 can realize the positioning and clamping of the workpiece blank 9.

[0048] This invention also provides a method for precision electrolytic forming of involute internal splines with auxiliary anode protection, the method comprising the following steps:

[0049] Step 1: Fix the machine tool spindle chuck 1 to the machine tool spindle, fix the cathode chuck 2 to the machine tool spindle chuck 1, and fix the tooling base 14 to the machine tool base;

[0050] Step 2: Connect the wire through the wire hole 4a and the inner wall groove 4b to the terminal 5a of the auxiliary anode protection cylinder 5. Install the auxiliary anode protection cylinder 5 on the insulating sealing cylinder 4. Install the insulating sealing cylinder 4, the cathode upper end face conformal insulation 6 and the tool cathode 7 on the cathode connecting rod 3. Install the cathode lower end face insulation 8 on the tool cathode 7.

[0051] Step 3: Install the workpiece hole wall insulation 13 on the workpiece blank 9, place the workpiece blank 9 on the tooling base 14, put the conical slit bushing 12 into the gap formed between the workpiece blank 9 and the tooling base 14, install the clamping screw cap 11 on the tooling base 14, and install the insulating water sealing cavity 10 on the clamping screw cap 11.

[0052] Step 4: Connect the tooling base 14 to the positive terminal of the machine tool, connect the machine tool spindle chuck 1 to the negative terminal of the machine tool, and connect the auxiliary anode protection cylinder 5 to the positive terminal of the auxiliary anode power supply; start the electrolytic machining machine tool, perform pre-fluid flow to check the sealing of the tooling flow channel, and then control the machine tool spindle to perform tool setting;

[0053] Step 5: Set the electrolytic machining process parameters, introduce the electrolyte to start machining. As the machine tool spindle feeds, the involute spline gradually takes shape due to the electrochemical anodic dissolution effect.

[0054] Step 6: After processing is completed, stop the fluid flow, remove the workpiece blank 9, and shut down the machine tool.

[0055] It should be noted that the above process operations can be combined to varying degrees. For the sake of brevity, the implementation methods of various combinations will not be elaborated here. Those skilled in the art can flexibly adjust the order of the above operation steps or flexibly combine the above steps according to actual needs.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A precision electrolytic forming apparatus for auxiliary anode protection involute internal spline, characterized in that, include: Workpiece positioning and clamping assembly and cathode assembly; The workpiece positioning and clamping assembly is fixed on the machine tool base, and the cathode assembly is fixed on the machine tool spindle. The cathode assembly is driven by the machine tool spindle to feed along the axis of the workpiece blank (9). The workpiece positioning and clamping assembly includes an insulating water-sealing cavity (10), a clamping screw cap (11), a tapered slit bushing (12), a workpiece hole wall insulation (13), and a tooling base (14). The tooling base (14) is fixed on the machine tool base, the workpiece hole wall insulation (13) is fixed on the workpiece blank (9), the tapered slit bushing (12) is placed in the gap formed between the workpiece blank (9) and the tooling base (14), the clamping screw cap (11) is fixed on the tooling base (14) by a threaded connection, and the insulating water-sealing cavity (10) is fixed on the clamping screw cap (11). The cathode assembly includes a machine tool spindle chuck (1), a cathode chuck (2), a cathode connecting rod (3), an insulating sealing cylinder (4), an auxiliary anode protection cylinder (5), a cathode upper end face conformal insulation (6), a tool cathode (7), and a cathode lower end face insulation (8). The machine tool spindle chuck (1) is fixed to the machine tool spindle, the cathode chuck (2) is fixed to the machine tool spindle chuck (1), the cathode connecting rod (3) is fixed to the cathode chuck (2), the auxiliary anode protection cylinder (5) is mounted on the insulating sealing cylinder (4), the insulating sealing cylinder (4), the cathode upper end face conformal insulation (6), and the tool cathode (7) are fixed to the cathode connecting rod (3), and the cathode lower end face insulation (8) is fixed to the tool cathode (7); wherein: The insulating sealing cylinder (4), the cathode upper end face conformal insulation (6), and the cathode lower end face insulation (8) are used to cover the surface of the cathode connecting rod (3) and the upper and lower end faces of the tool cathode (7), respectively; wherein: An auxiliary anode protection cylinder (5) is provided above the cathode upper end face conformal insulation (6). The auxiliary anode protection cylinder (5) is provided with a terminal (5a). The insulating sealing cylinder (4) is provided with a wire-passing hole (4a) and an inner wall groove (4b). One end of the wire is connected to the terminal (5a) of the auxiliary anode protection cylinder (5) through the wire-passing hole (4a) and the inner wall groove (4b), and the other end is connected to the positive terminal of the auxiliary anode power supply. The workpiece hole wall insulation (13) protects the non-machined area of ​​the inner hole of the workpiece blank (9) by insulating cover; wherein: The auxiliary anode protection cylinder (5) has a higher potential than the workpiece anode. During processing, the secondary corrosion of the tool cathode (7) on the machined tooth surface is effectively reduced by the method of insulation protection and electric field regulation by sacrificing the auxiliary anode, thereby improving the machining accuracy of the involute spline.

2. The apparatus according to claim 1, characterized in that, in: The workpiece positioning and clamping assembly is provided with a freely sliding conical slit bushing (12). After placing the workpiece blank (9) on the tooling base (14), it is placed in the gap formed between the workpiece blank (9) and the tooling base (14). Tightening the clamping screw cap (11) can achieve the positioning and clamping of the workpiece blank (9).

3. The apparatus according to claim 1 or 2, characterized in that, in: The cathode assembly and the workpiece positioning and clamping assembly together form a closed cavity. The cathode assembly is hollow inside for the electrolyte to flow in from the front. The insulating water-sealing cavity (10) is provided with an electrolyte outflow interface, from which the electrolyte flows out after the cavity is filled.

4. A method for precision electrolytic forming of involute internal splines with auxiliary anode protection using the apparatus described in any one of claims 1 to 3, characterized in that: The method includes the following steps: Step 1: Fix the machine tool spindle chuck (1) to the machine tool spindle, fix the cathode chuck (2) to the machine tool spindle chuck (1), and fix the tooling base (14) to the machine tool base; Step 2: Connect the wire through the wire hole (4a) and the inner wall groove (4b) to the terminal (5a) of the auxiliary anode protection cylinder (5), install the auxiliary anode protection cylinder (5) on the insulating sealing cylinder (4), install the insulating sealing cylinder (4), the cathode upper end face conformal insulation (6) and the tool cathode (7) on the cathode connecting rod (3), and install the cathode lower end face insulation (8) on the tool cathode (7); Step 3: Install the workpiece hole wall insulation (13) on the workpiece blank (9), place the workpiece blank (9) on the tooling base (14), put the conical slit bushing (12) into the gap formed between the workpiece blank (9) and the tooling base (14), install the clamping screw cap (11) on the tooling base (14), and install the insulating water sealing cavity (10) on the clamping screw cap (11); Step 4: Connect the tooling base (14) to the positive terminal of the machine tool, connect the machine tool spindle chuck (1) to the negative terminal of the machine tool, and connect the auxiliary anode protection cylinder (5) to the positive terminal of the auxiliary anode power supply; start the electrolytic machining machine tool, perform pre-fluid flow to check the sealing of the tooling flow channel, and then control the machine tool spindle to perform tool setting; Step 5: Set the electrolytic machining process parameters, introduce the electrolyte to start machining. As the machine tool spindle feeds, the involute spline gradually takes shape due to the electrochemical anodic dissolution effect. Step 6: After processing is completed, stop the fluid flow, remove the workpiece blank (9), and shut down the machine tool.

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