Cathode for electrochemical machining of large-caliber complex spiral wires with replaceable working teeth

Abstract

The present invention belongs to the technical field of electrolytic machining, and specifically relates to a large-caliber complex spiral wire electrolytic machining cathode with replaceable working teeth. The present invention includes a front guide, a cathode body and a rear guide. The original integral cathode body is changed into a split structure, and the cathode working teeth are fixedly connected to the cathode body; a connector plus a protective sleeve structure is provided at one end connected to the pull rod, and the cathode body and the connector can be replaced in case of failure. A cavity is provided between the cathode connector and the front guide, and an inclined hole for liquid outlet is provided on the front guide to increase the pressure of the electrolyte. The present invention can realize the engineering application of electrolytic machining technology for large-caliber complex spiral wire parts such as gun barrel rifling, special-shaped spiral splines, and oil drilling all-metal screw drill tools, which can effectively shorten the cathode development cycle and reduce costs.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolytic machining, and in particular relates to a large-caliber complex spiral wire electrolytic machining cathode with replaceable working teeth. Background Art

[0002] Large-caliber (caliber ≥ 80mm) complex spiral (length ≥ 8000mm, spiral groove width > 6mm, depth > 2mm) parts are widely used in gun barrel rifling, special-shaped spiral splines, oil drilling all-metal screw drill stators and screw pumps. This type of parts uses traditional mechanical broaching methods, which not only has high tool prices, but also extremely expensive processing costs; with the further improvement of material hardness, the material hardness of new products reaches HRC48-50, and the spiral groove becomes deeper and deeper, traditional mechanical broaching is difficult to carry out and has low production efficiency.

[0003] Since the 1950s, with the continuous development of CNC electrolytic machining technology. In the processing of spiral wires in small and medium-caliber deep holes (such as small and medium-caliber gun barrel rifling), electrolytic machining has basically replaced traditional mechanical broaching. However, for the large-caliber complex spiral wire parts mentioned in the present invention, after literature search, the relevant invention patent has been authorized, patent number: ZL 201310559158.8, the differences in the cathode structure are as follows: 1. There is no liquid increase hole on the original cathode working tooth. Under the conditions of long-term, high-current, small gap, and high-flow rate processing, the original cathode may be short-circuited during the electrolytic machining process, or the temperature of the cathode working teeth in the local area is high, and the cathode generates a lot of heat, resulting in the phenomenon of burning the insulating layer. 2. When the original cathode is initially processed, that is, when the cathode tooth has not yet completely entered the part with a large-diameter deep long hole, the electrolyte enters the processing gap from the inclined hole. When the electrolyte flows, it often flows in a direction that is conducive to the water flow; the original cathode tooth structure wants the electrolyte to flow from the large end of the cathode tooth to the small end, consistent with the direction of cathode movement, but it requires an additional sealing device to achieve this, which not only increases the manufacturing cost of the parts, but also increases the difficulty of precision electrolytic processing of large-diameter deep spirals. 3. The two-section holes (leakage hole B, leakage hole A) in the original patent need to be installed accurately, which is not only difficult to process, but also reduces the strength of the cathode body and the rear guide. 4. The thread in front of the original cathode body is connected to the horizontal electrolytic processing rod by thread. Long-term installation and disassembly of the cathode will cause thread wear. Once worn, the entire cathode body needs to be replaced, which wastes materials and increases costs. Summary of the invention

[0004] In view of this, the present invention provides a large-caliber complex spiral wire electrolytic machining cathode with replaceable working teeth.

[0005] In order to solve the problems existing in the prior art, the technical solution of the present invention is: a large-caliber complex spiral wire electrolytic machining cathode with replaceable working teeth, comprising a cathode body, a front guide, a rear guide, an end cover and working teeth, and an inclined hole is arranged on the front guide; the cathode body is composed of a connector, a connector and a copper tooth segment, which are connected in sequence from front to back, and the working teeth are arranged on the copper tooth segment, and a liquid increase hole is arranged on the working teeth, and the connector is a reducer tube, and the large end extends into the front end of the connector and is fixedly connected; the middle part of the connector is circumferentially evenly distributed with liquid inlet holes, and the outer port of the liquid inlet hole is located in the cavity between the inner wall of the front guide and the outer wall of the connector, and the rear end of the connector is provided with a shaft shoulder; the copper tooth segment is a barrel-shaped structure, and the annular end cover arranged at the front end is arranged on the inner side of the shaft shoulder of the connector through a clamping nut, and a rear guide is arranged between the rear end and the end cover.

[0006] The front guide is a barrel-shaped structure with an annular end cover at the front end, a front nut is arranged on the outer side of the annular end cover, and the inner side surface of the end cover is threadedly connected to the front outer wall of the liquid inlet hole on the connector; the rear end of the front guide is tightly matched with the positioning step on the outer side of the copper tooth segment.

[0007] The connector is threadedly connected to the connector and fastened with a locking nut; a protective sleeve is provided on the outer side of the front end of the connector, and the protective sleeve is a barrel-shaped structure with an annular end cover at the front end; the connector is passed through and fixed in the annular end cover, and the rear end of the protective sleeve is pressed and arranged on the outer side of the front nut.

[0008] The working teeth are all provided with liquid-increasing holes, and the liquid-increasing holes are arranged in double rows from front to back along the length direction on each working tooth, in a 2-3 arrangement.

[0009] The diameter of the liquid-increasing hole is 1.5 mm.

[0010] Compared with the prior art, the advantages of the present invention are as follows:

[0011] 1. The working teeth of the present invention are provided with liquid-increasing holes, and liquid is introduced through the liquid-inlet holes and discharged through the inclined holes, thereby increasing the pressure of the electrolyte. As the processing cross-sectional area increases, the flow direction of the electrolyte is changed, so that the electrolyte flows along the tooth tip to the tooth tail when entering the processing gap, and can take away the electrolysis products faster. The electrolyte is effectively increased to ensure that the flow field in the processing gap area (i.e., the area with the largest processing cross-sectional area) at the cathode tail remains full and sufficient, thereby achieving stable and reliable processing;

[0012] 2. The present invention designs the original integral cathode body into three sections, wherein the connector and the cathode connector are designed to be detachably connected. Once worn, only the connector needs to be replaced. Working teeth are arranged on the copper tooth section, and the working teeth are easy to replace, which can effectively save production costs. At the same time, the connector is connected to the pull rod. Once a connection failure occurs, only the connector needs to be replaced. The additional protective cover can better protect the non-processed parts of the cathode.

[0013] 3. In the present invention, a cavity is set between the cathode connector and the front guide, and liquid is introduced through the liquid inlet hole and discharged through the inclined hole, thereby increasing the pressure of the electrolyte; at the same time, the flow direction of the electrolyte is changed, so that the electrolyte flows along the tooth tip to the tooth tail when entering the processing gap, and can take away the electrolysis products faster.

[0014] 4. The cathode provided by the present invention can realize the engineering application of electrolytic processing technology for wire parts such as gun barrel rifling, special-shaped spiral splines, and oil drilling all-metal screw drill tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A half-section view of the structure of the present invention;

[0016] Figure 2 yes Figure 1 The cross-section diagram at AA;

[0017] Figure 3 is a half-section view of a cathode body with working teeth of the present invention;

[0018] Figure 4 yes Figure 3 BB section diagram;

[0019] Figure 5 Schematic diagram of the tooth surface of the cathode working tooth of the present invention;

[0020] Figure 6 It is a schematic diagram of the cross section of the machined part;

[0021] In the figure: 1. Protective sleeve; 2. Locking nut; 3. Connector; 4. Front nut; 5. Connector; 6. Sealing ring; 7. Front guide; 8. Oblique hole; 9. Pressing nut; 10. Copper tooth segment; 11. Rear guide; 12. End cover; 13. Liquid inlet hole; 14. Working tooth; 15. Liquid increase hole. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] The present embodiment provides a large-caliber complex spiral wire electrolytic machining cathode with replaceable working teeth, including a cathode body, a front guide 7, a rear guide 11, an end cover 12 and working teeth 14. The front guide 7 has a plurality of inclined holes 8 distributed circumferentially, and its aperture is smaller than the liquid inlet hole 13 on the cathode connector 5, and a plurality of sealing rings 6 are arranged on its outer surface; the cathode body is composed of a connector 3, a connector 5 and a copper tooth segment 10, which are connected in sequence from front to back, and 48 three-sided feed cone-shaped working teeth 14 are arranged on the outer surface of the cathode body 10, and the working teeth 14 are provided with liquid increase holes 15. The connector 3 is a reducer, and the large end extends into the front end of the connector 5 and is fixedly connected; the small end is connected to the pull rod during processing. The middle part of the connector 5 is evenly distributed with liquid inlet holes 13 in the circumferential direction, and the outer port of the liquid inlet hole 13 is located in the cavity between the inner wall of the front guide 7 and the outer wall of the connector 5. The rear end of the connector 5 is provided with a shoulder. The copper tooth segment 10 is a barrel-shaped structure, and the annular end cover provided at the front end is arranged on the inner side of the shoulder of the connector 5 through a clamping nut 9. A rear guide 11 is provided between the rear end and the end cover 12. The end cover 12 is made of polytetrafluoroethylene material and is installed at the tail of the copper tooth segment by a threaded connection method to press the rear guide 11.

[0024] The front guide 7 is a barrel-shaped structure with an annular end cover at the front end, and a front nut 4 is arranged on the outer side of the annular end cover, and the inner side surface of the end cover is threadedly connected to the front outer wall of the liquid inlet hole 13 on the connector 5; the rear end of the front guide 7 is tightly matched with the positioning step on the outer side of the copper tooth segment 10.

[0025] The front guide 7 and the rear guide 11 are made of polytetrafluoroethylene, and are provided with a sealing ring 6. The front guide 7 is sleeved on the cathode connector 5 and the cathode body 10 and fastened with a front nut 4; the rear guide 11 is sleeved on the tail of the cathode body 10, and both connections are bonded with epoxy resin.

[0026] The tubular structure of the connector 3 is threadedly connected to the connector 5 and fastened with a locking nut 2; a protective sleeve 1 is provided on the outside of the front end of the connector 5, and the protective sleeve 1 is made of insulating material. The protective sleeve 1 is a barrel-shaped structure with an annular end cover provided at the front end. The connector 3 is inserted and fixed in the annular end cover, covering the connection section of the connector 3 and the cathode connector 5, which can better protect the unprocessed part of the entire cathode. The rear end of the protective sleeve 1 is pressed and arranged on the outside of the front nut 4.

[0027] The working teeth 14 are all provided with liquid increasing holes 15 , and the liquid increasing holes 15 are arranged in double rows from front to back along the length direction on each working tooth 14 , forming a 2-3 arrangement.

[0028] The front guide 7 and the rear guide 11 are made of polytetrafluoroethylene, and a sealing ring 6 is provided thereon.

[0029] The diameter of the liquid increasing hole 15 is 1.5 mm, and the diameter of the liquid inlet hole 13 is larger than the inclined hole 8 .

[0030] The connector 5 is made of brass and has a tubular structure.

[0031] See also Figure 6 Large-caliber (caliber ≥ 80mm) complex spiral wire (length ≥ 8000mm, spiral groove width > 6mm, depth > 2mm) parts are widely used in gun barrel rifling, special-shaped spiral splines, oil drilling all-metal screw drill stators and screw pumps.

[0032] During processing, the electrolyte flows into the cathode connector 5 from the front end of the hole in the connector 3, flows into the cavity between the connector 5 and the front guide 7 through the liquid inlet hole 13 on the cathode connector 5, and then flows out from the inclined hole 8 into the processing gap, realizing stable electrolytic processing, taking away the heat and electrolytic products generated by the processing, and being guided out of the processing area through the rear guide 11.

[0033] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A large-caliber complex spiral wire electrolytic machining cathode with replaceable working teeth, comprising a cathode body, a front guide (7), a rear guide (11), an end cover (12) and working teeth (14), wherein an inclined hole (8) is provided on the front guide (7); the characteristics are: The cathode body is composed of a connector (3), a connector (5) and a copper tooth segment (10) connected in sequence from front to back. The working tooth (14) is arranged on the copper tooth segment (10), and a liquid increase hole (15) is arranged on the working tooth (14). The connector (3) is a variable diameter tube, and the large end thereof extends into the front end of the connector (5) and is fixedly connected. Liquid inlet holes (13) are evenly distributed in the circumferential direction in the middle of the connector (5), and the outer end of the liquid inlet holes (13) is located in the cavity between the inner wall of the front guide (7) and the outer wall of the connector (5). The rear end of the connector (5) is provided with a shaft shoulder. The copper tooth segment (10) is a barrel-shaped structure, and an annular end cover arranged at the front end is arranged on the inner side of the shaft shoulder of the connector (5) through a clamping nut (9), and a rear guide (11) is arranged between the rear end and the end cover (12); the front guide (7) is a barrel-shaped structure with an annular end cover arranged at the front end. The structure comprises a front nut (4) on the outer side of the annular end cover, the inner side surface of which is threadedly connected to the front outer wall of the liquid inlet hole (13) on the connector (5); the rear end of the front guide (7) is tightly matched with the positioning step on the outer side of the copper tooth segment (10); the connector (3) is threadedly connected to the connector (5) and is fastened with a locking nut (2); a protective sleeve (1) is provided on the outer side of the front end of the connector (5), the protective sleeve (1) is a barrel-shaped structure with an annular end cover on the front end, the connector (3) is fixed in the annular end cover, and the rear end of the protective sleeve (1) is pressed against the outer side of the front nut (4); the working teeth (14) are all provided with liquid increase holes (15), and the liquid increase holes (15) are arranged in double rows from front to back along the length direction on each working tooth (14), which are arranged in a 2-3 manner; the diameter of the liquid increase holes (15) is 1.5 mm; The diameter of the liquid inlet hole (13) is larger than that of the inclined hole (8), thereby increasing the pressure of the electrolyte; The electrolyte flows from the front end of the hole in the connector (3) into the cathode connector (5), flows from the liquid inlet hole (13) on the cathode connector (5) into the cavity between the connector (5) and the front guide (7), and then flows out from the inclined hole (8) into the processing gap, changing the flow direction of the electrolyte so that the electrolyte flows along the tooth tip of the working tooth (14) to the tooth tail when entering the processing gap, thereby achieving stable electrolytic processing, taking away the heat and electrolytic products generated by the processing, and being discharged from the processing area through the rear guide.

Images