Small-size variable cross-section external spline integrated electrolytic forming device and method

Abstract

The application discloses a small-size variable cross-section outer spline integrated electrolytic forming machining device and method, and the device comprises a cathode mounting block, a tool cathode, an annular electrolyte flow guide cavity, a workpiece positioning cavity and a workpiece positioning base which are sequentially arranged from top to bottom and are arranged on the same axis, a variable cross-section machining blade of the tool cathode is arranged at the center position of the tool cathode, the outer contour of the variable cross-section machining blade is in the shape of a horn mouth, the inner wall of the variable cross-section machining blade is provided with cathode teeth with the same number of teeth as the workpiece, an insulating bus cavity is embedded at the center hole of the upper end of the tool cathode, the outer wall of the annular electrolyte flow guide cavity is provided with electrolyte input channels and is internally provided with an electrolyte rectifying area, a circular channel is formed in the workpiece positioning cavity, the workpiece base is fixed on a horizontal worktable of a machine tool, and a rectangular groove for axial and angular positioning of a workpiece blank is formed at the center position in the interior of the base. The application can improve machining efficiency and has high tooth profile precision; the electrolyte flow channel adopting a reverse flow flow field design can effectively improve flow field uniformity.

Description

Technical Field

[0001] This invention belongs to the field of small-size external spline processing and manufacturing technology, specifically relating to an integrated electrolytic forming processing device and method for small-size variable cross-section external splines. Background Technology

[0002] Spline connections evolved from key connections and are used to transmit torque and rotational motion. They offer significant advantages in connections requiring high centering accuracy, large loads, and frequent sliding. Furthermore, spline structures are compact and easy to install. Spline connections consist of internal and external splines. For small-sized external splines, the structural channels are narrow, opening is poor, and requirements for geometric accuracy and surface quality are stringent. Directly applying existing research results is insufficient to meet the comprehensive requirements of manufacturing quality, efficiency, and cost.

[0003] Electrolytic machining (EMC) offers unique advantages over cold extrusion forming, machining, and wire EDM. Based on the principle of electrochemical anodic dissolution, EMC removes excess material. During the process, a consistent machining gap is maintained between the workpiece anode and the tool cathode, resulting in no wear on the tool cathode, which retains its shape and dimensions for extended use. Furthermore, if the machining process is stable, short-circuit ablation or other phenomena will not occur between the tool cathode and the workpiece anode. Additionally, EMC does not generate macroscopic cutting forces, thus preventing residual stress and deformation in the parts. Compared to EDM and machining, EMC is approximately 5 to 10 times more efficient, making it an ideal process for machining small-sized external splines.

[0004] However, for electrochemical machining of small-sized variable cross-section external splines, the spline tooth profile is complex, the channels are narrower, and the curvature of the tooth root and tooth tip varies greatly. The electrochemical dissolution law of each position of the spline is different, and the electrochemical machining forming law is complex. Therefore, based on the structural characteristics of small-sized variable cross-section external splines, this paper explores a new electrochemical machining method and designs a corresponding machining device in combination with the electrochemical machining principle. This is expected to improve the uniformity of the electrochemical machining flow field and improve the machining stability and machining accuracy. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a small-sized variable cross-section external spline integrated electrolytic forming machining device and method. This method utilizes a tool cathode that is continuously vibrated and fed along the machine tool spindle in the direction of the workpiece blank to complete the machining of small-sized variable cross-section external splines. The machining device includes: a cathode mounting block, an insulating manifold, a tool cathode, an annular electrolyte guiding cavity, a workpiece positioning base, and a workpiece positioning base groove. The outer contour of the variable cross-section machining edge of the tool cathode is flared, and its inner wall is provided with cathode teeth of the same number as the workpiece teeth, which correspond to the workpiece tooth grooves during machining to ensure the machining process. The cathode ensures that all points on the workpiece blank have the same dissolution rate at different feed depths. This invention uses a tool cathode with a variable cross-section machining edge to electrolytically form small-sized variable cross-section external splines, eliminating the need for traditional post-spline polishing and deburring processes. This not only improves machining efficiency but also ensures high tooth profile accuracy. The electrolyte flow channel with a reverse flow field design effectively improves flow field uniformity, solving problems such as difficulty in flow field control, machining efficiency, surface quality, and machining accuracy in electrolytic machining of small-sized variable cross-section external splines, thus achieving precise and efficient manufacturing of small-sized variable cross-section external splines.

[0006] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0007] A small-sized variable cross-section external spline integrated electrolytic forming processing device includes a cathode mounting block, a tool cathode, an annular electrolyte guiding cavity, a workpiece positioning cavity, and a workpiece positioning base arranged sequentially from top to bottom and with their centers on the same axis.

[0008] The cathode mounting block has electrolyte output channels on both the left and right sides and is detachably and fixedly mounted on the machine tool spindle, connected to the negative terminal of the machine tool power supply.

[0009] The tool cathode is provided with a variable cross-section machining blade at its center. The inner wall of the variable cross-section machining blade is provided with cathode teeth with the same number of teeth as the workpiece, and they correspond to the workpiece tooth grooves during electrolytic machining. An insulating busbar cavity is embedded in the center hole at the upper end of the tool cathode, and the insulating busbar cavity is connected to the electrolyte output channel.

[0010] The outer wall of the annular electrolyte guiding cavity is evenly distributed with multiple electrolyte input channels, and an electrolyte rectification area is provided inside. The bottom of the electrolyte rectification area is a certain distance from the bottom surface of the annular electrolyte guiding cavity, so that the electrolyte flows into the processing gap at a uniform speed after passing through the rectification area.

[0011] A circular channel is opened at the center of the workpiece positioning cavity, and during the clamping process, the channel completely penetrates the workpiece positioning cavity, and the inner wall of the circular channel is in close contact with the cylindrical surface of the workpiece blank.

[0012] The workpiece base is fixed on the horizontal worktable of the machine tool, and a rectangular groove for axial and angular positioning of the workpiece blank is opened at the center of the workpiece base. The workpiece base is connected to the positive terminal of the machine tool power supply.

[0013] To optimize the above technical solution, the specific measures also include:

[0014] The tool cathode mounting block is horizontally aligned with the machine tool spindle and then fastened with screws at its upper end. Its lower end is connected to the tool cathode. Both the tool cathode and the tool cathode mounting block are provided with a pair of pin holes at different angles.

[0015] The aforementioned insulated busbar cavity is made of plastic.

[0016] The workpiece positioning cavity is detachably and fixedly connected to the workpiece positioning base.

[0017] The outer contour shape of the tool cathode variable cross-section machining edge is a flared mouth, which ensures that the tool cathode has the same dissolution rate at all points of the workpiece blank under different feed depths.

[0018] The inner wall of the aforementioned insulating busbar cavity is provided with the number of teeth and tooth grooves corresponding to the cross-section machining edge of the tool cathode. The outer wall of the insulating busbar cavity is provided with a pair of pin holes, which serve as angular positioning during installation. Axial positioning can be achieved through the two planes on top of the pin holes.

[0019] It also includes a cathode insulating layer, wherein the tool cathode is provided with multiple threaded holes for detachable and fixed connection with the tool cathode mounting block and the cathode insulating layer;

[0020] The cathode insulating layer is provided with a pair of pin holes and multiple threaded holes. After being positioned with the tool cathode through the pin holes, it is fixedly connected to the tool cathode with an internal hexagon screw.

[0021] The cathode insulating layer has a flared hole at its center, which corresponds to the variable cross-section machining edge of the tool cathode, and the inner wall of the flared hole is in contact with the outer wall of the variable cross-section machining edge of the tool cathode.

[0022] It also includes a second sealing ring, which is disposed between the workpiece blank and the sidewall of the central hole of the annular electrolyte guide cavity.

[0023] It also includes a first sealing ring and a third sealing ring;

[0024] The electrolyte sealing cavity is detachably fixed to the annular electrolyte guiding cavity by means of an internal hexagonal screw;

[0025] The first sealing ring is disposed between the tool sidewall and the insulating sealing cavity;

[0026] The third sealing ring is positioned between the annular electrolyte flow chamber and the insulating sealing chamber to prevent electrolyte splashing during processing.

[0027] Small-size variable cross-section external spline integral electrolytic forming processing method, including:

[0028] The workpiece positioning cavity is detachably fixed to the workpiece positioning base, so that the bottom surface of the workpiece positioning cavity is in close contact with the top surface of the workpiece base. The end of the workpiece blank is embedded in the corresponding groove of the workpiece positioning base, and the bottom surface of the groove is used as the axial positioning of the workpiece blank, and the two mutually perpendicular sides of the groove are used as the angular positioning of the workpiece blank.

[0029] The workpiece blank is restricted from moving radially by the circular channel of the workpiece positioning cavity, and the inner wall of the circular channel of the workpiece positioning cavity is tightly fitted to the cylindrical surface of the workpiece blank.

[0030] Align the cathode mounting block horizontally with the machine tool spindle, then position it using two pairs of pin holes at different angles, and detachably fix it to the machine tool spindle using hexagon socket screws; embed the insulating manifold into the center hole corresponding to the tool cathode, and position it angularly using the two pairs of pin holes corresponding to it, while the upper and lower planes can be used for axial positioning; tightly fit the upper surface of the tool cathode with the bottom surface of the cathode mounting block, position it using two pairs of pin holes at different angles, and then fasten the connection with hexagon socket screws;

[0031] After being positioned with the workpiece positioning cavity through the two pin holes provided in the annular electrolyte guiding cavity, the electrolyte guiding cavity is placed horizontally on the upper end of the workpiece positioning cavity and fixedly connected by hexagonal screws.

[0032] After aligning the cathode mounting block horizontally with the machine tool spindle, fasten it with screws and connect it to the negative terminal of the machine tool power supply; connect the workpiece base to the machine tool horizontal worktable with screws and simultaneously connect it to the positive terminal of the machine tool power supply.

[0033] Insert the dry electrolyte pipe into the electrolyte inlet channel of the electrolyte guide cavity and the electrolyte outlet channel of the cathode mounting block, and test the electrolyte flow to check the sealing condition;

[0034] Set the electrolytic machining process parameters for the variable cross-section external spline. The tool cathode is continuously fed along the machine tool spindle towards the workpiece direction, causing anodic dissolution on the workpiece blank surface and gradually machining the variable cross-section external spline into shape.

[0035] The present invention has the following beneficial effects:

[0036] This invention discloses a small-size variable cross-section external spline electrolytic forming apparatus and method. It employs an electrochemical anodic dissolution principle to remove excess material, thereby achieving workpiece blank forming. This invention has the following advantages over cold extrusion forming, machining, and wire EDM:

[0037] 1) High workpiece surface quality: When machining single or multiple slots on high-strength steel, problems often arise such as the cutting tool being unable to penetrate, and the resulting slot width having a flared opening and a tapered bottom. Wire EDM is often the only option, but it leaves a remelted layer, affecting the workpiece surface quality. This invention, however, employs a small-size variable cross-section external spline integrated electrolytic forming method. This method removes excess material through ionization and is a cold-processing process, thus eliminating defects such as recast layers and microcracks on the machined surface.

[0038] 2) High processing efficiency: Compared with tooth-by-tooth machining, the one-piece forming of the external spline of the present invention is simple to operate and the cathode movement trajectory is simple. It can achieve its fine machining by simply feeding continuously towards the workpiece. At the same time, it eliminates the polishing and deburring processes after the traditional machining of external splines, and the processing efficiency is significantly improved.

[0039] 3) Low cost and long service life of the tool cathode: High machining accuracy can only be achieved after rough forming of the external spline and subsequent form grinding. During form grinding, the service life of the CBN grinding wheel is greatly reduced due to frequent bearing and belt breakage, resulting in higher machining costs. However, this invention uses a small-size variable cross-section external spline integrated electrolytic forming machining method, allowing the tool cathode to be made of lower-cost materials such as stainless steel. Furthermore, during the machining process, there is always a certain machining gap between the tool cathode and the workpiece anode, so theoretically, the shape and size of the cathode will not cause any wear and tear, allowing for long-term use.

[0040] 4) Wide processing range: The processing technology of this invention removes excess material in the form of ions, so it can process various difficult-to-cut metal materials, including high-strength steel, cemented carbide and quenched steel; secondly, for external splines with different parameters (module, number of teeth and pressure angle, etc.) with variable or constant cross-section, only the cathode needs to be replaced for processing, which can greatly reduce the processing cost of parts.

[0041] 5) No macroscopic cutting force: In the process of integral electrolytic forming of small-sized variable cross-section external splines, a certain distance is left between the anode and cathode for the electrolyte to flow in. That is, during normal processing, the two will not come into direct contact. Therefore, no mechanical cutting force will be generated during the processing, and no residual stress, deformation, or burrs will be generated as a result.

[0042] 6) High processing accuracy: The device of this invention adopts a reverse flow pattern. In this pattern, the electrolyte converges from the electrolyte inlet to the electrolyte outlet. Compared with forward flow and lateral flow, the flow field has better uniformity and no cavitation phenomenon occurs. Therefore, this pattern is more conducive to improving the accuracy and stability of electrolytic processing. Attached Figure Description

[0043] Figure 1 This is a structural view of a small-size variable cross-section external spline integral forming processing device according to the present invention;

[0044] Figure 2 These are perspective views and partial enlarged views of the parts after electrolytic processing according to the present invention;

[0045] Figure 3 This is a cross-sectional view of the tool cathode of the present invention;

[0046] Figure 4 This is a structural view of the electrolyte flow channel of the present invention;

[0047] Figure 5 This is a structural view of the workpiece positioning cavity of the present invention;

[0048] Figure 6 This is a cross-sectional structural view of the insulating sealing cavity of the present invention;

[0049] Figure 7 This is a structural view of the insulating busbar cavity of the present invention;

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Cathode mounting block; 2. Insulating manifold; 3. Tool cathode; 4. Insulating sealing cavity; 5. Input channel; 6. Annular electrolyte guiding cavity; 7. Workpiece positioning cavity; 8. Workpiece positioning base; 9. Output channel; 10. Cathode insulating layer; 11. Electrolyte rectification area; 12. Workpiece blank; 13. Groove; 14. Tool cathode variable cross-section machining edge; 15. First sealing ring; 16. Second sealing ring; 17. Third sealing ring. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0053] Although the steps in this invention are arranged by reference numerals, this is not intended to limit the order of the steps. Unless the order of the steps is explicitly stated or the execution of a step requires other steps as a basis, the relative order of the steps can be adjusted. It is understood that the term "and / or" as used herein refers to and covers any and all possible combinations of one or more of the associated listed items.

[0054] like Figures 1-7 As shown, the present invention provides a small-sized variable cross-section external spline integrated electrolytic forming processing device, comprising a cathode mounting block 1, a tool cathode 3, an annular electrolyte guiding cavity 6, a workpiece positioning cavity 7, and a workpiece positioning base 8 arranged sequentially from top to bottom and with their centers on the same axis;

[0055] The cathode mounting block 1 has electrolyte output channels 9 on both the left and right sides, and is detachably and fixedly mounted on the machine tool spindle and connected to the negative terminal of the machine tool power supply.

[0056] The tool cathode 3 is provided with a variable cross-section machining blade 14 at its center. The inner wall of the variable cross-section machining blade 14 is provided with cathode teeth with the same number of teeth as the workpiece, and they correspond to the workpiece tooth grooves during the electrolytic machining process. An insulating manifold 2 is embedded in the center hole at the upper end of the tool cathode 3. The insulating manifold 2 is connected to the electrolyte output channel 9, which is conducive to the timely discharge of electrolyte from the machining gap.

[0057] The outer wall of the annular electrolyte guiding cavity 6 is evenly distributed with multiple electrolyte input channels 5, and an electrolyte rectification area 11 is provided inside. High-speed flowing electrolytes with different directions and flow rates flow into the processing gap at a uniform speed after passing through the electrolyte rectification area 11. The bottom of the electrolyte rectification area 11 is left with a certain distance from the bottom surface of the annular electrolyte guiding cavity 6, so that the high-speed flowing electrolyte flows into the processing gap at a uniform speed after passing through the rectification area, which can effectively avoid the phenomenon of insufficient liquid and eddy current.

[0058] A circular channel is opened at the center of the workpiece positioning cavity 7, and during the clamping process, the channel completely penetrates the workpiece positioning cavity 7. The inner wall of the circular channel is in close contact with the cylindrical surface of the workpiece blank 12 to restrict the radial movement of the workpiece blank 12.

[0059] The workpiece base 8 is fixed on the horizontal worktable of the machine tool, and a rectangular groove 13 for axial and angular positioning of the workpiece blank is opened at the center of the workpiece base 8. The workpiece base 8 is connected to the positive terminal of the machine tool power supply.

[0060] In a preferred but non-limiting embodiment of the present invention, "small size" generally refers to an external spline tooth tip circle diameter of Ф.

[0061] 4.4-4.5mm, the minimum diameter of the tooth root circle is Ф3.7-3.8mm.

[0062] Preferably, the upper end of the tool cathode mounting block 1 is horizontally aligned with the machine tool spindle and then fastened with screws, and the lower end is connected to the tool cathode 3. Both the tool cathode 3 and the tool cathode mounting block 1 are provided with a pair of pin holes at different angles.

[0063] Electrolytes with different directions and flow rates flow into the processing gap at a uniform speed after passing through the electrolyte rectification zone 11;

[0064] As the tool cathode 3 continues to feed towards the workpiece, the small-sized variable cross-section spline gradually takes shape, and during the processing, the electrolyte flows towards the insulating manifold 2 in a converging manner. After the electrolyte merges in the insulating manifold 2, it flows towards the output channel 9.

[0065] The insulating manifold 2 is detachably fixedly connected to the groove inside the tool cathode 3, and its sidewalls can be insulated to prevent stray currents from causing secondary corrosion to the workpiece. This flow field design can effectively improve the flow field uniformity, which is beneficial to improving the surface quality and machining accuracy of the workpiece.

[0066] Preferably, the insulating busbar 2 is made of plastic to prevent stray current from affecting the non-processing area;

[0067] The workpiece positioning cavity 7 is detachably and fixedly connected to the workpiece positioning base 8. For workpiece blanks of the same type with different shapes and sizes, it is easy to disassemble and install, and can be replaced as needed, making it highly adaptable.

[0068] Preferably, the outer contour shape of the tool cathode variable cross-section machining blade 14 is a flared mouth, ensuring that the tool cathode 3 has the same dissolution rate at all points of the workpiece blank 12 under different feed depths.

[0069] Preferably, the inner wall of the insulating manifold 2 is provided with the number of teeth and the tooth groove corresponding to the cross-section machining blade 14 of the tool cathode, which is conducive to the orderly flow of electrolyte to the output channel 9 after machining. Secondly, it can avoid secondary corrosion caused by stray current and effectively improve the machining accuracy and surface quality of the workpiece. The outer wall of the insulating manifold 2 is provided with a pair of pin holes, which are used for angular positioning during installation. Axial positioning can be achieved through the two planes on its upper surface.

[0070] Preferably, it also includes a cathode insulating layer 10, and the tool cathode 3 is provided with a plurality of threaded holes for detachable fixed connection with the tool cathode mounting block 1 and the cathode insulating layer 10;

[0071] The cathode insulating layer 10 is provided with a pair of pin holes and multiple threaded holes. After being precisely positioned with the tool cathode 3 through the pin holes, it is fixedly connected to the tool cathode 3 with an internal hex screw.

[0072] The cathode insulating layer 10 has a flared hole at its center, which corresponds to the tool cathode variable cross-section machining blade 14. The inner wall of the flared hole is in contact with the outer wall of the tool cathode variable cross-section machining blade 14, which can effectively prevent secondary corrosion of the workpiece anode caused by stray current brought by high-speed flowing electrolyte.

[0073] Preferably, it further includes a second sealing ring 16, which is disposed between the workpiece blank 12 and the side wall of the central hole of the annular electrolyte guiding cavity 6, to prevent the electrolyte from flowing out along the axial direction of the workpiece blank during the processing, thus affecting the stability of the processing and the processing accuracy.

[0074] That is, the inner central hole sidewall of the annular electrolyte guiding cavity 6 is provided with a second sealing ring 16 to prevent the electrolyte from flowing out along the axial direction of the workpiece blank during the processing, which would affect the stability of the processing process; the annular electrolyte guiding cavity 6 is made of plastic material, which can reduce the processing cost of the device.

[0075] Preferably, it also includes a first sealing ring 15 and a third sealing ring 17;

[0076] The electrolyte sealing cavity 4 is detachably fixed to the annular electrolyte guiding cavity 6 by means of an internal hexagon screw.

[0077] The first sealing ring 15 is disposed between the tool sidewall and the insulating sealing cavity 4;

[0078] The third sealing ring 17 is disposed between the annular electrolyte guiding cavity 6 and the insulating sealing cavity 4 to prevent electrolyte splashing during processing.

[0079] A method for integral electrolytic forming of small-sized variable cross-section external splines according to the aforementioned device, the method comprising:

[0080] First, the workpiece positioning cavity 7 is detachably fixed to the workpiece positioning base 8, so that the bottom surface of the workpiece positioning cavity 7 is in close contact with the top surface of the workpiece base 8. Next, the end of the workpiece blank 12 is embedded in the corresponding groove 13 of the workpiece positioning base 8, and the bottom surface of the groove 13 is used as the axial positioning of the workpiece blank 12, and the two mutually perpendicular sides of the groove 13 are used as the angular positioning of the workpiece blank 12.

[0081] Finally, the workpiece blank 12 is restricted to move radially by the circular channel of the workpiece positioning cavity 7, and the inner wall of the circular channel of the workpiece positioning cavity 7 is tightly fitted with the cylindrical surface of the workpiece blank 12, which can ensure that the workpiece blank is clamped stably and firmly.

[0082] Align the cathode mounting block 1 horizontally with the machine tool spindle, then position it using two pairs of pin holes at different angles, and detachably fix it to the machine tool spindle using hexagon socket screws; detachably insert the insulating manifold 2 into the groove on the upper end face of the tool cathode 3, embed the insulating manifold 2 into the corresponding center hole of the tool cathode 3, and position it angularly using two pairs of pin holes; the upper and lower planes can be used for axial positioning; tightly fit the upper end face of the tool cathode 3 with the bottom surface of the cathode mounting block 1, and after positioning it using two pairs of pin holes at different angles, fasten it with hexagon socket screws; that is, detachably fix the tool cathode 3 and the cathode mounting block 1 using hexagon socket screws, while precisely positioning them using two pairs of pin holes at different angles;

[0083] The inner wall of the tool cathode variable cross-section machining blade 14 has cathode teeth with the same number of teeth as the workpiece, and corresponds to the workpiece tooth groove during machining; the cathode insulating layer 10 and the tool cathode 3 are detachably fastened together by hexagonal screws, and the inner wall of the central horn hole of the cathode insulating layer 10 is tightly fitted to the outer wall of the tool cathode variable cross-section machining blade 14.

[0084] After being positioned with the workpiece positioning cavity 7 through the two pin holes provided in the annular electrolyte guiding cavity 6, the electrolyte guiding cavity 6 is horizontally placed on the upper end of the workpiece positioning cavity 7 and fixedly connected by hexagon socket screws; the annular electrolyte guiding cavity 6 and the electrolyte sealing cavity 4 are detachably fixedly connected by hexagon socket screws; specifically, the protrusion of the insulating sealing cavity 4 extends into the annular electrolyte guiding cavity 6 and is detachably fixedly connected by hexagon socket screws.

[0085] After aligning the cathode mounting block 1 horizontally with the machine tool spindle, fasten it with screws and connect it to the negative terminal of the machine tool power supply; connect the workpiece base 8 to the machine tool horizontal worktable with screws and simultaneously connect it to the positive terminal of the machine tool power supply.

[0086] Insert the dry electrolyte pipe into the electrolyte inlet channel 5 of the electrolyte guide cavity 6 and the electrolyte outlet channel 9 of the cathode mounting block 1, and test the electrolyte flow to check the sealing condition.

[0087] The electrolytic machining process parameters for the variable cross-section external spline are set as follows: electrolyte is 10% NaNO3, machining voltage is 12.5V, electrolyte inlet pressure is 1.0MPa, outlet pressure is 0.2MPa, electrolyte temperature is 298K, and a cathode vibration and DC power supply machining mode is adopted with an amplitude of 0.3mm and a vibration frequency of 10Hz. Under the above specific process conditions, the tool cathode 3 is continuously fed along the machine tool spindle towards the workpiece direction, causing anodic dissolution on the surface of the workpiece blank 12, gradually machining the variable cross-section external spline. This process can efficiently and stably remove excess material, perform precision forming, and smooth the surface of the workpiece blank, and can meet the requirements of high-efficiency, high-quality, and low-cost machining.

[0088] Specifically, the electrolyte rectification zone 11 ensures that electrolytes with different directions and flow rates flow uniformly into the machining gap after passing through the electrolyte rectification zone 11, preventing electrolyte shortage and eddy current phenomena. As the tool cathode continues to feed towards the workpiece, the small-sized variable cross-section spline gradually takes shape, and during the machining process, the electrolyte flows convergently towards the insulating manifold 2. After the electrolytes converge in the insulating manifold 2, they flow to the output channel 9. The insulating manifold 2 is detachably fixedly connected to a groove provided inside the tool cathode, and its sidewalls can be insulated to prevent stray currents from causing secondary corrosion to the workpiece. This flow field design can effectively improve the uniformity of the flow field, which is beneficial to improving the surface quality and machining accuracy of the workpiece.

[0089] Example 1

[0090] like Figures 1-7 As shown, Embodiment 1 of the present invention is a small-sized variable cross-section external spline integrated electrolytic forming processing device, which mainly includes:

[0091] The workpiece includes a cathode mounting block 1, an insulating manifold 2, a tool cathode 3, an annular electrolyte guiding cavity 6, a workpiece positioning base 8, and a workpiece positioning base groove 13. The workpiece positioning base 8 has a rectangular groove 13 on its bottom surface. The end of the workpiece blank 12 is placed in this rectangular groove, and axial positioning is achieved through the bottom surface of the groove. Two mutually perpendicular sides are used for angular positioning. Since the axial dimension of the workpiece blank 12 is much larger than its radial dimension, the workpiece positioning cavity 7 is required to provide radial clamping to prevent the workpiece blank from shaking due to high-frequency vibration of the tool cathode and high-speed flow of electrolyte during processing, thus affecting processing stability and accuracy. After the tool cathode mounting block 1 is horizontally aligned with the machine tool spindle, it is fixedly connected by screws, and electrolyte output channels are provided on both its left and right sides. Before the tool cathode 3 is detachably fixedly connected to the tool cathode mounting block 1, it is first positioned by a pair of pin holes with different angles on both parts to avoid workpiece machining defects caused by installation errors. The annular electrolyte guiding cavity 6 is provided with an electrolyte rectification area 11, and the bottom of the electrolyte rectification area is left with a certain distance from the bottom surface of the annular electrolyte guiding cavity 6, so that the high-speed flowing electrolyte flows into the machining gap at a uniform speed after passing through the rectification area of ​​the device, which can effectively avoid the phenomenon of insufficient liquid and eddy current.

[0092] In this embodiment, the workpiece positioning cavity 7 and the workpiece positioning base 8 are fixedly connected by screws, and during the installation process, it should be ensured that the side of the workpiece positioning cavity 7 is always perpendicular to the machine tool horizontal worktable.

[0093] In this embodiment, the upper end of the tool cathode mounting block is fixedly connected to the machine tool spindle by screws, and the lower end is provided with two pairs of pin holes of different diameters and angles. The large pin hole is used to accurately position the workpiece positioning cavity during the installation process, and the small pin hole is used to position the cathode center insulation device. At the same time, multiple threaded holes are provided for fixed connection with the tool cathode 3.

[0094] In this embodiment, the inner wall of the tool cathode variable cross-section machining blade 14 is provided with cathode teeth with the same number of teeth as the workpiece. During the machining process, the cathode teeth correspond to the workpiece tooth grooves, and the outer contour shape is a trumpet shape, ensuring that the tool cathode has the same dissolution rate at all points of the workpiece under different feed depths. The tool cathode 3 is provided with multiple threaded holes, which can be reliably connected to the tool cathode mounting block 1 and the cathode insulation layer 10.

[0095] In this embodiment, the insulating manifold 2 is embedded in the center of the tool cathode groove, and is angularly positioned by a pair of pin holes at different angles, and axially positioned by the upper and lower planes. Its inner wall is provided with toothed grooves that match the workpiece, which is conducive to the timely discharge of electrolyte from the processing gap. The insulating manifold 2 is made of plastic material, which can prevent stray current from affecting the non-processing area.

[0096] In this embodiment, the central hole of the cathode insulating layer 10 is provided with a flared hole corresponding to the variable cross-section machining edge 14 of the tool cathode. During clamping, the inner wall of the central hole of the cathode insulating layer 10 should be tightly fitted with the outer wall of the variable cross-section machining edge 14 of the tool cathode to avoid stray currents caused by high-speed flowing electrolyte, which could lead to secondary corrosion of the workpiece anode. The cathode insulating layer is provided with a pair of pin holes and multiple threaded holes. After being precisely positioned with the tool cathode through the pin holes, it is fastened to the tool cathode 10 with screws. The cathode insulating layer 10 is made of plastic, which can effectively prevent stray currents.

[0097] In this embodiment, the annular electrolyte guiding cavity 6 is provided with a second sealing ring on the side wall of the central hole to prevent the electrolyte from flowing out along the axial direction of the workpiece blank during processing, thus affecting the stability of the processing process; the annular electrolyte guiding cavity 6 is provided with multiple threaded holes, which are detachably fixed to the insulating sealing cavity 4 by means of hexagonal screws.

[0098] A method for integral electrolytic forming of small-sized variable cross-section external splines, utilizing a small-sized variable cross-section external spline integral electrolytic forming apparatus, specifically includes the following steps:

[0099] Step 1: Place the workpiece positioning base 8 on the horizontal worktable of the machine tool, and ensure that the side of the workpiece positioning base 8 is perpendicular to the horizontal worktable of the machine tool. Then, use hexagon socket screws to detachably fix it to the horizontal worktable of the machine tool.

[0100] Step 2: Place the workpiece positioning cavity 7 on the upper end of the workpiece positioning base 8, ensuring that the bottom surface of the workpiece positioning cavity 7 is completely in contact with the top surface of the workpiece positioning base 8, and fix it with hexagon socket screws; then, make it tightly in contact with the side of the workpiece blank 12 through the central through channel of the workpiece positioning cavity 7, to ensure that it is clamped stably and firmly, and to avoid shaking caused by high-speed flowing electrolyte and high-frequency vibration of the cathode during the processing, which would affect the stability of the processing process.

[0101] Step 3: Place the end of the workpiece blank 12 into the groove 13 of the workpiece positioning base, and use the bottom surface of the groove to axially position the workpiece blank 12. The two mutually perpendicular sides are used for angular positioning. When installing the workpiece blank 12, the end of the blank should be completely in contact with the bottom surface of the groove so that the side of the workpiece blank is always perpendicular to the horizontal worktable of the machine tool. This can ensure the shape accuracy and dimensional accuracy of the small-size variable cross-section spline after processing.

[0102] Step 4: After aligning the tool cathode mounting block 1 with the machine tool spindle horizontally, fix it in place with hexagon socket screws. During the installation process, use a pair of pin holes with different angles inside to accurately position it with the workpiece positioning cavity 7 to ensure accurate subsequent installation.

[0103] Step 5: Detachably insert the insulating manifold 2 into the center hole of the tool cathode 3 and position it through the pin hole to ensure that the inner wall groove of the insulating manifold 2 and the inner wall groove of the tool cathode variable cross-section machining blade 14 are on the same plane.

[0104] Step 6: Fit the end of the tool cathode 3 without the machining edge tightly to the bottom surface of the tool cathode mounting block 1, and after precise positioning through pin holes at different angles, make a detachable fixed connection.

[0105] Step 7: Insert the second sealing ring 16 into the groove on the side wall of the center hole of the annular electrolyte guiding cavity 6, position the two pin holes inside with the workpiece positioning cavity 7, and fix them together with hexagonal screws; fix the annular electrolyte guiding cavity 6 and the electrolyte sealing cavity 4 together with hexagonal screws in a detachable manner.

[0106] Step 8: Fix the cathode insulating layer 10 to the tool cathode 3, and during the clamping process, the inner wall of the center hole of the cathode insulating layer 10 should be tightly fitted to the outer wall of the tool cathode variable cross-section machining blade 14;

[0107] Step 9: Insert the first sealing ring 15 into the groove on the upper surface of the insulating sealing device, and insert the third sealing ring 17 into the groove on the outer wall of the tool cathode;

[0108] Step 10: Insert the dried liquid-passing pipe into the electrolyte guiding cavity 6 and the input channel 5 and output channel 2 corresponding to the tool cathode mounting block 1;

[0109] Step 11: Connect the tool cathode mounting block 1 to the negative terminal of the machine tool, and connect the workpiece positioning base 13 to the positive terminal of the machine tool;

[0110] Step 12: Before starting the machine, check whether the power supply, chiller, compressed air, and electrolyte filtration system are normal, and check whether there are any abnormalities on the outside of the machine. After the inspection, test the electrolyte and check the sealing.

[0111] Step 13: Set the process parameters for the variable cross-section spline electrolytic machining: the electrolyte is 10% NaNO3, the machining voltage is 12.5V, the electrolyte inlet pressure is 1.0MPa, the outlet pressure is 0.2MPa, the electrolyte temperature is 298K, the machining mode is cathode vibration and DC power supply, the amplitude is 0.3mm, the vibration frequency is 10Hz, and the conduction angle is 150°;

[0112] Step Fourteen: Continuously feed the tool cathode 10 along the direction of the machine tool spindle to complete the integral forming of the variable cross-section spline. After that, cut off the power, raise the machine tool spindle a certain distance, take out the processed part, and rinse it with clean water.

[0113] Step 15: Measure and record the processed sample using a coordinate measuring machine, analyze the normal error between each point and the theoretical surface, and further correct and optimize multiple parameters through multiple experiments until the processing meets the design requirements.

[0114] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0115] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A small-sized variable cross-section external spline integrated electrolytic forming processing device, characterized in that: It includes a cathode mounting block (1), a tool cathode (3), an annular electrolyte guiding cavity (6), a workpiece positioning cavity (7), and a workpiece positioning base (8), arranged sequentially from top to bottom with their centers on the same axis. Electrolyte output channels (9) are opened on both the left and right sides of the cathode mounting block (1), and are detachably fixed on the machine tool spindle and connected to the negative terminal of the machine tool power supply; the upper end of the tool cathode mounting block (1) is horizontally aligned with the machine tool spindle and then fastened with screws, and the lower end is connected to the tool cathode (3), and both the tool cathode (3) and the tool cathode mounting block (1) are provided with a pair of pin holes at different angles; The tool cathode (3) is provided with a tool cathode variable cross-section machining blade (14) at its center. The inner wall of the tool cathode variable cross-section machining blade (14) is provided with cathode teeth with the same number of teeth as the workpiece, and they correspond to the workpiece tooth grooves during electrolytic machining. An insulating manifold (2) is embedded in the center hole at the upper end of the tool cathode (3), and the insulating manifold (2) is connected to the electrolyte output channel (9). The outer contour shape of the tool cathode variable cross-section machining blade (14) is a flared mouth, which ensures that the tool cathode (3) has the same dissolution rate at each point of the workpiece blank (12) under different feed depths. The outer wall of the annular electrolyte guiding cavity (6) is evenly distributed with multiple electrolyte input channels (5), and an electrolyte rectification area (11) is provided inside. The bottom of the electrolyte rectification area (11) is a certain distance from the bottom surface inside the annular electrolyte guiding cavity (6), so that the electrolyte flows into the processing gap at a uniform speed after passing through the rectification area. A circular channel is opened at the center of the workpiece positioning cavity (7), and the channel completely penetrates the workpiece positioning cavity (7). During the clamping process, the inner wall of the channel is in close contact with the cylindrical surface of the workpiece blank (12). The workpiece base (8) is fixed on the horizontal worktable of the machine tool, and a rectangular groove (13) for axial and angular positioning of the workpiece blank is opened at the center of the workpiece base (8). The workpiece base (8) is connected to the positive terminal of the machine tool power supply.

2. The small-size variable cross-section external spline integrated electrolytic forming processing device according to claim 1, characterized in that: The insulating junction box (2) is made of plastic. The workpiece positioning cavity (7) is detachably fixedly connected to the workpiece positioning base (8).

3. The small-size variable cross-section external spline integrated electrolytic forming processing device according to claim 1, characterized in that: The inner wall of the insulating manifold (2) is provided with the number of teeth and tooth grooves corresponding to the tool cathode variable cross section machining blade (14). The outer wall of the insulating manifold (2) is provided with a pair of pin holes, which are used for angular positioning during installation. Axial positioning can be achieved through the two planes on its upper surface.

4. The small-size variable cross-section external spline integrated electrolytic forming processing device according to claim 1, characterized in that: It also includes a cathode insulating layer (10), and the tool cathode (3) is provided with multiple threaded holes for detachable fixed connection with the tool cathode mounting block (1) and the cathode insulating layer (10); The cathode insulating layer (10) is provided with a pair of pin holes and multiple threaded holes. After being positioned with the tool cathode (3) through the pin holes, it is fixedly connected to the tool cathode (3) with an internal hexagon screw. The cathode insulating layer (10) has a horn hole at its center that corresponds to the tool cathode variable cross-section machining edge (14), and the inner wall of the horn hole is in contact with the outer wall of the tool cathode variable cross-section machining edge (14).

5. The small-size variable cross-section external spline integrated electrolytic forming processing device according to claim 1, characterized in that: It also includes a second sealing ring (16), which is disposed between the workpiece blank (12) and the side wall of the central hole of the annular electrolyte guide cavity (6).

6. The small-size variable cross-section external spline integrated electrolytic forming processing device according to claim 1, characterized in that: It also includes a first sealing ring (15) and a third sealing ring (17); The electrolyte sealing cavity (4) is detachably fixed to the annular electrolyte guiding cavity (6) by means of an internal hexagon screw; The first sealing ring (15) is disposed between the tool sidewall and the insulating sealing cavity (4); The third sealing ring (17) is placed between the annular electrolyte guide cavity (6) and the insulating sealing cavity (4) to prevent electrolyte splashing during processing.

7. A method according to claim 1 6. A method for integral electrolytic forming of small-sized variable cross-section external splines using any of the aforementioned devices, characterized in that: The method includes: The workpiece positioning cavity (7) is detachably fixed to the workpiece positioning base (8), so that the bottom surface of the workpiece positioning cavity (7) is tightly fitted with the top surface of the workpiece base (8). The end of the workpiece blank (12) is embedded in the corresponding groove (13) of the workpiece positioning base (8), and the bottom surface of the groove (13) is used as the axial positioning of the workpiece blank (12), and the two mutually perpendicular sides of the groove (13) are used as the angular positioning of the workpiece blank (12). The workpiece blank (12) is restricted from moving radially by the circular channel of the workpiece positioning cavity (7), and the inner wall of the circular channel of the workpiece positioning cavity (7) is tightly fitted with the cylindrical surface of the workpiece blank (12). Align the cathode mounting block (1) horizontally with the machine tool spindle, then position it using two pairs of pin holes at different angles, and use hexagonal screws for detachable and fixed connection to the machine tool spindle; embed the insulating manifold (2) into the center hole corresponding to the tool cathode (3), and position it angularly using two pairs of pin holes, while the upper and lower planes can be used for axial positioning; fit the upper end face of the tool cathode (3) tightly against the bottom surface of the cathode mounting block (1), and after positioning it using two pairs of pin holes at different angles, fasten it with hexagonal screws; After positioning the workpiece positioning cavity (7) with the two pin holes provided in the annular electrolyte guiding cavity (6), the electrolyte guiding cavity (6) is placed horizontally on the upper end of the workpiece positioning cavity (7) and fixedly connected by internal hexagon screws; After aligning the cathode mounting block (1) with the machine tool spindle horizontally, tighten the connection with screws and connect it to the negative terminal of the machine tool power supply; connect the workpiece base (8) to the machine tool horizontal worktable with screws, and simultaneously connect the positive terminal of the machine tool power supply; insert the dry electrolyte pipe into the electrolyte input channel (5) of the electrolyte guide cavity (6) and the electrolyte output channel (9) of the cathode mounting block (1), and test the electrolyte flow to check the sealing condition; Set the electrolytic machining process parameters for the variable cross-section external spline. The tool cathode (3) feeds continuously along the machine tool spindle towards the workpiece direction, causing anodic dissolution on the surface of the workpiece blank (12) to gradually shape the variable cross-section external spline.

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