A Quick-Change Electrolytic Machining Cathode with an Inner Spiral Stator Made of Metal

Abstract

The present invention proposes a quick-change cathode for electrolytic machining of a metal internal spiral stator. The device comprises a front guide, a cathode body, an end forming piece, a rear guide, a rear guide, a plug, and an end cap. The left end of the cathode body is connected to the front guide, and the right end is symmetrically arranged along the axis and formed into a plane on the outer wall surface, so that the outer wall surface of the right end forms a positioning arc positioning plane structure of "arc segment + plane segment + arc segment + plane segment". The right end is coaxially connected to the end forming piece, the rear guide, the rear guide, and the plug in sequence. The rear guide achieves automatic centering and positioning via the positioning arc positioning plane structure. The rear guide and the rear guide are clearance-matched for automatic centering. The plug and end cap are used to seal and insulate the cathode body. The present invention solves the problems of difficult assembly and short cathode life in existing internal spiral electrolytic machining cathodes for screw drilling tools.

Description

Technical Field

[0001] The invention belongs to the field of electrolytic machining, and in particular relates to a metal inner spiral stator quick-change electrolytic machining cathode. Background Art

[0002] See also Figures 1 to 3 Patent number ZL 201710997262.3, entitled "200 mm diameter constant wall thickness screw drill stator spiral electrolytic machining cathode," discloses a cathode structure consisting of a front guide 1, a cathode body 2, roughing working teeth 3, finishing working teeth 4, and a rear plug 5. The general scheme is that the front guide 1 and the cathode body 2 are a combination, and the front guide 1 and the cathode body 2 are coaxial. The diversion channel behind the liquid outlet of the front guide 1 is connected to the diversion channel on the cathode body 2; the finishing working teeth 4 and the roughing working teeth 3 are embedded in each other to form a combination. The inner hole size of the front guide 1 matches that of the cathode body 2, and the inner hole size is 0.5 to 1.5 mm larger than that of the cathode body 2. The connection between the front guide 1 and the cathode body 2 is made by cold-coated epoxy resin bonding. The insulation between the cathode body 2 and the combination of the finishing working teeth 4 and the roughing working teeth 4 and the roughing working teeth 3 is made by traditional thermosetting casting. There are three defects:

[0003] ① When the roughing working tooth 3 and the finishing working tooth 4 are assembled into a combined body, since they rely solely on the hole-axis fit, the finishing working tooth 4 can inevitably rotate around the axis during assembly, making the tooth shapes of the two working teeth extremely prone to misalignment. Therefore, assembly is extremely dependent on the skill level of the assembler, and after assembly, both require 16 hours to 20 hours of repair and polishing to ensure a smooth transition between the tooth surfaces of the working teeth. At the same time, different operators have different assembly skills, making it difficult to ensure assembly accuracy when replacing the finishing working teeth, which in turn affects the replication molding accuracy of the cathode.

[0004] ② After the roughing working teeth 3 and the finishing working teeth 4 are assembled and aligned, they rely solely on a hole-shaft fit and lack a structure to secure them. Therefore, when the rear plug 5 is installed, friction between the end faces often causes the finishing working teeth 4 to rotate, resulting in misalignment between the finishing working teeth 4 and the roughing working teeth 3. Therefore, in production practice, after the roughing working teeth 3 and the finishing working teeth 4 are assembled, threaded holes are often drilled on the rear end faces of the assembly and screws are used to secure the connection between the two. This way, when the rear plug 5 is installed, the finishing working teeth will not rotate, thus avoiding misalignment between the roughing working teeth 3 and the finishing working teeth 4.

[0005] ③ When screws are used to fix the roughing working teeth 3 and the fine-machining working teeth 4, the fine-machining working teeth 4 often need to be replaced due to wear. Each time the fine-machining working teeth 4 are replaced, the threaded holes need to be re-drilled. As a result, the rear end face of the roughing working teeth is covered with threaded holes. However, due to the limited position of the rear end face, after the fine-machining working teeth are replaced 4 times, the rear end face is basically covered with threaded holes and cannot be re-drilled. The cathode body 1 and the roughing working teeth 3 can only be scrapped, resulting in a significant shortening of the service life of the cathode body 1 and the roughing working teeth 3. Summary of the Invention

[0006] The present invention provides a quick-change electrolytic machining cathode for a metal inner spiral stator in order to solve the problems of difficult assembly and short cathode life in existing screw drill internal spiral electrolytic machining cathodes.

[0007] The technical solution of the present invention is: a metal inner spiral stator quick-change electrolytic machining cathode, comprising a front guide 6, a cathode body 7, an end forming sheet 8, a rear guide 9, a rear guide 10, a plug 11 and an end cover 12;

[0008] The left end of the cathode body 7 is connected to the front guide 6, and the right end is symmetrically arranged on the outer wall surface along the axis, so that the outer wall surface of the right end forms a positioning arc positioning plane structure of "circular arc segment + plane segment + circular arc segment + plane segment"; the right end is coaxially connected to the end forming piece 8, the rear guide 9, the rear guide 10 and the plug 11 in sequence;

[0009] The rear guide 9 realizes automatic centering and positioning through the positioning arc positioning plane structure;

[0010] The rear guide 10 and the rear guide 9 are clearance-matched to achieve automatic centering;

[0011] The plug 11 and the end cover 12 are used for sealing and insulating the cathode body 7 .

[0012] A further technical solution of the present invention is: the cathode body 7 is a multi-stage columnar body, which is divided into AB segment, BC segment and CD segment as a whole, the AB segment is the left end, the BC segment is the middle part, and the CD segment is the right end; the AB segment is a second-stage rotating body, and a liquid guide hole is opened on the large diameter end; a plurality of working teeth are opened on the BC segment along the circumferential direction of the axis of the cathode body 7; the outer diameter of the CD segment is smaller than the outer diameter of the BC segment.

[0013] A further technical solution of the present invention is: the working teeth are formed as an external spiral cone as a whole, the bottom end forms a continuous petal shape on the C end face, and the top end forms a semicircular protrusion on the B end face, and there is a distance between the protrusions; the tooth body parts of the working teeth are at a distance from each other and do not contact each other, and the tooth bodies deflect in the same direction.

[0014] A further technical solution of the present invention is: the terminal forming piece 8 is a petal-shaped ring part, the inner wall of the ring part is consistent with the positioning arc positioning plane structure of the cathode body 7CD segment, and the terminal forming piece 8 is gap-fitted with the cathode body 7CD segment. After fitting, the terminal forming piece 8 is flush with the end face of the cathode body 7C.

[0015] A further technical solution of the present invention is: the rear guide 9 is an annular part as a whole, the outer wall is a second-order columnar body, the large diameter end is petal-shaped, the inner wall is consistent with the positioning arc positioning plane structure of the cathode body 7CD segment, and this structure is gap-matched with the cathode body 7CD segment. After matching, the large diameter end is flush with the end face of the cathode body 7C.

[0016] A further technical solution of the present invention is that the rear guide 10 is an annular member, and the central through hole is in clearance fit with the outer cylinder of the rear guide to play a supporting role.

[0017] A further technical solution of the present invention is that the plug 11 is connected to the cathode body through threads to form a "full coverage" insulating environment at the rear end to avoid stray corrosion.

[0018] A further technical solution of the present invention is that the end cap 12 is connected to the cathode copper body 7 through threads to seal the high-pressure electrolyte in the inner cavity of the cathode body 7 to prevent the high-pressure electrolyte from cracking the plug 11.

[0019] A further technical solution of the present invention is that the end cap 12 is connected to the cathode copper body 7 through threads to seal the high-pressure electrolyte in the inner cavity of the cathode body 7 to prevent the high-pressure electrolyte from cracking the plug 11.

[0020] Effects of the Invention

[0021] Compared with the existing technology and process solutions, the advantages of the present invention are as follows:

[0022] ① Thanks to the centering arc + positioning plane structural design at the tail end of the cathode body 7, the inner holes of the terminal forming piece 8 and the rear guide 9 also have the same structural design. In this way, during assembly, the arc plays a centering role and the plane plays a positioning function, so that the terminal forming piece 8 and the rear guide 9 are not only coaxial with the cathode body 7 during assembly, but also do not produce radial rotation during assembly. The cathode body working teeth, the terminal forming piece working teeth, and the rear guide teeth will not be misaligned. It is only necessary to assemble the terminal forming piece and the rear guide according to the assembly positioning relationship. The process is simple and convenient, and the skill level requirement for the operator is greatly reduced;

[0023] ② Due to the centering arc + positioning plane structure design at the tail end of the cathode body 7, the terminal forming piece 8 will not rotate during or after assembly, so there is no need to use threaded holes to fix the connection between the two, greatly improving the life of the cathode body. At the same time, when the terminal forming piece is severely worn and needs to be replaced, it can be replaced in just 5 minutes, achieving the goal of rapid replacement;

[0024] ③ Since the rear section of the rear guide 9 is a cylindrical surface, the inner hole of the rear guide 10 is in clearance with it. After electrolytic machining, the inner spiral profile is processed to the required size. The outer circle of the rear guide 10 is in clearance with the inner profile of the part after machining, which plays a supporting role. When the outer surface of the rear guide 10 is scratched due to wear, it can be reused by simply rotating the angle, and the service life is long; BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the electrolytic machining cathode design structure diagram disclosed in ZL 201710997262.3

[0026] Figure 2 yes Figure 1 Part drawing of medium rough machining working tooth 3

[0027] Figure 3 yes Figure 1 Parts drawing of medium finishing working tooth 4

[0028] Figure 4 This is a schematic diagram of the cathode structure design for electrolytic machining as described in the patent of this invention.

[0029] Figure 5 yes Figure 4 Cross-sectional view

[0030] Figure 6 yes Figure 4 Parts diagram of the front guide 6

[0031] Figure 7 yes Figure 4 Parts diagram of cathode body 7 Figure 8 yes Figure 7 Left view of the cathode body

[0032] Figure 9 yes Figure 7 Right view of the cathode body

[0033] Figure 10 yes Figure 7 Cross-sectional view of cathode body 7

[0034] Figure 11 yes Figure 4 Parts diagram of the middle and end forming piece 8

[0035] Figure 12 yes Figure 4Parts diagram of center and rear spoiler 9

[0036] Figure 13 yes Figure 4 Parts diagram of center rear guide 10

[0037] Figure 14 yes Figure 4 Parts diagram of middle plug 11

[0038] Figure 15 yes Figure 4 Parts diagram of middle end cover 12

[0039] In the figure, 1-front guide, 2-cathode body, 3-rough working teeth, 4-fine working teeth, 5-rear plug, 6-front guide, 7-cathode body, 8-end forming piece, 9-rear guide, 10-rear guide, 11-plug, 12-end cover, 13-positioning arc; 14-positioning plane DETAILED DESCRIPTION

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0041] See also Figure 4-Figure 15 The present invention provides a quick-change electrolytic machining cathode for a metal inner spiral stator, comprising a front guide 6, a cathode body 7, an end forming piece 8, a rear guide 9, a rear guide 10, a plug 11, and an end cover 12; with the cathode body 7 as the central axis, the front guide 6 is assembled at the left end, and the connection method is epoxy glass glue; the inner hole and the outer surface of the cathode body 7 are coated with epoxy resin glue to enhance the stability of the connection; the end forming piece 8 is assembled through the centering arc + positioning plane at the rear end of the cathode body 7 through the hole-axis clearance, effectively avoiding tooth misalignment between the two and achieving the purpose of automatic centering and positioning; The rear guide 9 is assembled through the centering arc + positioning plane at the rear end of the cathode body 7 through the hole-axis clearance, which effectively avoids the tooth misalignment of the two and achieves the purpose of automatic centering and positioning; the central through hole of the rear guide 10 is matched with the clearance of the outer cylindrical surface of the rear guide 9 to achieve automatic centering; the plug 11 is connected to the cathode body 7 through a thread to form a "full coverage" insulating environment at the rear end to avoid stray corrosion; the end cover 12 is connected to the cathode body 7 through a thread to seal the high-pressure 1.5MPa electrolyte in the inner cavity of the cathode body 7 to avoid the high-pressure electrolyte from cracking the plug 11.

[0042] See also Figure 6 The front guide 6 is made of epoxy fiberglass rod and serves as a guide and rectifying element. Two annular grooves are located on the outer circumference, inlaid with O-rings to improve sealing with the prefabricated holes during axial movement. The rectifying section has 7 x Φ14 outlet holes evenly distributed. Epoxy glass glue is applied to the inner hole during assembly to enhance its connection to the cathode copper body 1. The outer circumferential mating section is machined to its final size during assembly, with a clearance of 0.05-0.1mm between the outer circumference and the prefabricated holes.

[0043] See also Figure 7 、 8 , 9, 10, the cathode body 7 is made of brass alloy H68, which plays a role in pre-corrosion during processing. Its working tooth part is in the shape of an outer spiral cone, and more than 90% of the processing allowance is removed; the left end has a cylindrical surface, which is bonded to the front guide by epoxy glass glue, and the right end has a centering arc + positioning plane, which is clearance-matched with the terminal forming piece 8 and the rear guide 9 to prevent axial movement and radial rotation. The inner hole is connected to the plug 11 through a thread, and the plug 11 presses the terminal forming piece 8 and the rear guide 9; both inner hole ends have a 60° groove for processing and assembly reference;

[0044] See also Figure 11 The end forming piece 8 is supported by brass alloy H68, which has a finishing effect and plays a decisive role in the shape and size of the inner contour of the part. The rear section has a 1mm cylindrical section to achieve an accurate "copy" of the shape; its inner cavity is a centering arc and a positioning plane design, and has the same structural clearance as the rear section of the cathode body 7, which is simple to assemble and easy to operate;

[0045] See also Figure 12 , the rear guide 9 is made of epoxy glass fiber reinforced plastic rod, which has a diversion function, and its inner cavity is a centering arc and a positioning plane design, which has the same structural clearance as the rear section of the cathode body 7, and is easy to assemble and operate;

[0046] See also Figure 13 The rear guide 10 is made of brass alloy H68, which has a supporting function. The central through hole and the outer cylindrical clearance of the rear guide are matched, and the gap between the two is between 0.03 and 0.05;

[0047] See also Figure 14 The plug 11 is made of epoxy glass fiber reinforced plastic rod and is connected to the cathode body 7 through a thread to form a rear end "full coverage" insulation environment to avoid stray corrosion.

[0048] See also Figure 15 The end cap 12 is made of brass alloy H68 and is connected to the cathode copper body 7 through a thread to seal the high-pressure 1.5MPa electrolyte in the inner cavity of the cathode body 7 to prevent the high-pressure electrolyte from cracking the plug 11.

[0049] When electrolytically machining the cathode parts, a margin is left for the outer circle of the front guide 6. After assembly, the outer circle of the front guide 6 is machined with the 60° grooves at both ends of the cathode body 7 as the reference to fully ensure its coaxiality with the cathode body 7, thereby ensuring the overall accuracy of the cathode.

[0050] The front guide 6 is clearance-fitted with the prefabricated hole before processing. Considering the thermal expansion of the parts, the clearance is about 0.02 to 0.06 mm.

[0051] The rear guide 10 is clearance-matched with the inner hole size after machining. Considering the tolerance zone distribution of the inner hole size, the clearance is about 0.1 mm.

[0052] During electrolytic machining, as the machine tool spindle feeds, the cathode feeds in the feed direction under the action of the spindle. At the same time, the electrolyte flows out from the 7×Φ14 outlet hole, and after being rectified by the front guide 6 rectification section, it flows through the outer spiral cone section of the cathode body 7 to rough-machine the working teeth, removing more than 90% of the remainder, and flows to the end forming piece 8. Under the action of voltage, the part material is removed in the "ionic state", and finally the final contour of the part is formed. The electrolyte flow field is a convergent flow field, which can fully ensure the accurate "copy" of the shape; then it flows out from the guide tooth surface of the rear guide 8 and returns to the electrolytic cell; the rear guide 9 is matched with the clearance of the part contour after machining, and supports the cathode after machining, playing the role of supporting the cathode.

Claims

1. A quick-change electrolytic machining cathode with a metal inner spiral stator, characterized in that: It comprises a front guide (6), a cathode body (7), an end forming sheet (8), a rear guide (9), a rear guide (10), a plug (11) and an end cover (12); The left end of the cathode body (7) is connected to the front guide (6), and the right end is symmetrically arranged on the outer wall surface along the axis, so that the outer wall surface of the right end forms a positioning arc positioning plane structure of "circular arc segment + plane segment + circular arc segment + plane segment"; the right end is coaxially connected to the end forming piece (8), the rear guide (9), the rear guide (10) and the plug (11) in sequence; The rear guide (9) realizes automatic centering and positioning through a positioning arc positioning plane structure; The rear guide (10) and the rear guide (9) are clearance-matched to achieve automatic centering; The plug (11) and the end cover (12) are used for sealing and insulating the cathode body (7); The cathode body (7) is used as the central axis, and the left end is assembled with the front guide (6), and the connection method is epoxy glass glue bonding; the inner hole of the front guide (6) and the outer surface of the cathode body (7) are coated with epoxy resin glue to enhance the connection stability; the end forming piece (8) passes through the centering arc + positioning plane at the rear end of the cathode body (7) and is assembled through the hole-axis gap to avoid the tooth shape misalignment of the two and achieve the purpose of automatic centering and positioning; the rear guide (9) passes through the centering arc + positioning plane at the rear end of the cathode body (7) and is assembled through the hole-axis gap The two components are assembled together to avoid tooth misalignment and achieve the purpose of automatic centering and positioning; the central through hole of the rear guide (10) and the outer cylindrical surface of the rear guide (9) are matched with each other in a clearance to achieve automatic centering; the plug (11) is connected to the cathode body (7) through a thread to form a rear end "full coverage" insulation environment to avoid stray corrosion; the end cover (12) is connected to the cathode body (7) through a thread to seal the high-pressure 1.5MPa electrolyte in the inner cavity of the cathode body (7) to prevent the high-pressure electrolyte from cracking the plug (11); The front guide (6) is made of epoxy glass fiber reinforced plastic rod, which plays the role of guiding and rectifying; there are two annular grooves on the outer circle, inlaid with O-rings to improve its sealing with the prefabricated hole during axial movement, and its rectifying section has 7×Φ14 liquid outlet holes evenly distributed; the inner hole is coated with epoxy glass glue during the assembly process to enhance the tightness of its connection with the cathode copper body (1); the outer circle matching section is processed to the final size during the assembly process, and the matching clearance with the prefabricated hole is 0.05~0.1mm.

2. A metal inner spiral stator quick-change electrolytic machining cathode according to claim 1, characterized in that: The cathode body (7) is a multi-stage columnar body, which is divided into an AB segment, a BC segment and a CD segment as a whole, wherein the AB segment is the left end, the BC segment is the middle portion and the CD segment is the right end; the AB segment is a second-stage rotating body and has a liquid guide hole on the large-diameter end; the BC segment has a plurality of working teeth circumferentially along the axis of the cathode body (7); and the outer diameter of the CD segment is smaller than that of the BC segment.

3. A quick-change electrolytic machining cathode with a metal inner spiral stator as claimed in claim 2, characterized in that: The working teeth are in the form of an external spiral cone as a whole, with the bottom end forming a continuous petal shape on the C end face and the top end forming a semicircular protrusion on the B end face, and there is a distance between the protrusions; the tooth body parts of the working teeth are at a distance from each other and do not contact each other, and the tooth bodies deflect in the same direction.

4. The metal inner spiral stator quick-change electrolytic machining cathode according to claim 1, characterized in that: The terminal forming piece (8) is a petal-shaped annular piece, the inner wall of which matches the positioning arc positioning plane structure of the CD segment of the cathode body (7), and the terminal forming piece (8) and the CD segment of the cathode body (7) are clearance-matched. After the fitting, the terminal forming piece (8) is flush with the C end face of the cathode body (7).

5. The metal inner spiral stator quick-change electrolytic machining cathode according to claim 1, characterized in that: The rear guide (9) is an annular part as a whole, the outer wall is a second-order columnar body, the large diameter end is petal-shaped, and the inner wall is consistent with the positioning arc positioning plane structure of the CD segment of the cathode body (7). This structure is in clearance fit with the CD segment of the cathode body (7). After fitting, the large diameter end is flush with the C end face of the cathode body (7).

6. The metal inner spiral stator quick-change electrolytic machining cathode according to claim 1, characterized in that: One end of the front guide (6) is provided with a spiral claw, which is sleeved on the AB section of the cathode body (7), and the claw seamlessly connects with the working teeth on the BC section.

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