Electrode structure, electrical discharge machining device and machining method

Abstract

The present invention relates to the technical field of electric spark discharge machining, and discloses an electrode structure, an electric spark machining device and a machining method, wherein the electrode structure includes a connecting member, whose axis is a first axis, and one end of the connecting member has a mounting portion; the electrode is hinged to the mounting portion through a hinge shaft, and the axis of the hinge shaft is a second axis; one end of the biasing member abuts against the connecting member, and the other end abuts against the electrode, applying a biasing force to the electrode tending to remain in the mounting portion; the connecting member can be driven to rotate around the first axis, and the electrode deflects out of the mounting portion and rotates around the second axis when the connecting member rotates. This allows the electrode to extend into a guide hole machined on a workpiece when the connecting member is not rotating, and to deflect out of the mounting portion to machine a rotating inner cavity or inner hole when the connecting member rotates to generate centrifugal force, thereby solving the problem that the electric spark equipment in the prior art cannot machine a rotating inner cavity or inner hole whose inner cavity diameter is larger than the orifice.

Description

Technical Field

[0001] The invention relates to the technical field of electric spark discharge machining, in particular to an electrode structure, an electric spark machining device and a machining method. Background Art

[0002] In the industrial field, there is a certain demand for inner holes with rotary structures. The traditional processing method for these inner holes is usually mechanical grinding, but this processing method has many defects, and some special inner holes cannot be processed. Therefore, electrical discharge machining has gradually become an alternative method.

[0003] Electrospark machining is a new method of processing materials that utilizes the electrical corrosion phenomenon generated by pulse discharge between two electrodes, which is different from traditional mechanical grinding. It has the characteristics of being soft over hard, precise and microscopic, and lifelike in profiling, and has become one of the important processing methods in the industrial field.

[0004] Electrospark discharge machining is widely used in the processing of mold holes and cavities in mold production, as well as the removal of metal residues such as screws, tools, taps, drills, plug gauges, etc. that are broken and retained in parts due to improper processing. Existing electrospark discharge machining equipment mainly includes an electrode and a feed shaft. The electrode and the feed shaft are coaxially arranged. The feed shaft drives the electrode to perform discharge machining along the electrode axis. This type of electrode can usually only process mold holes or cavities with simple shapes. For rotary cavities or rotary holes with an inlet diameter smaller than the inner cavity diameter, existing electrospark discharge machining equipment cannot complete the process and needs to be improved and designed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the technical problem that the electrode and the connecting part of the electric spark discharge machining equipment in the prior art are coaxially arranged, and the electrode is discharged along the axial direction, which cannot process a cavity or a hole with a small entrance and a large inner diameter, thereby providing a new electrode structure that can process a rotary cavity or a rotary hole with a small entrance and a large inner diameter, an electric spark machining device with the electrode structure, and a machining method of the electric spark machining device.

[0006] To this end, one of the objects of the present invention is to provide an electrode structure, comprising:

[0007] A connecting member, whose axis is a first axis, and one end of the connecting member has a mounting portion;

[0008] The electrode is hinged to the mounting portion via a hinge shaft, and the axis of the hinge shaft is a second axis;

[0009] A biasing member, one end of which abuts against the connecting member and the other end of which abuts against the electrode, applying a biasing force tending to keep the electrode in the mounting portion;

[0010] The connecting member can be driven to rotate around the first axis. When the connecting member rotates, the electrode is deflected out of the mounting portion and rotates around the second axis due to the centrifugal force to overcome the biasing force.

[0011] Optionally, in the electrode structure, the mounting portion is an embedding groove provided on the connecting member and recessed along the first axis toward away from the electrode, and the embedding groove is located on both sides of the electrode deflection direction and has openings for the electrode to deflect;

[0012] The electrode is a sheet-shaped electrode sheet, the second axis is perpendicular to the first axis, and the hinge shaft is hinged at the middle of the electrode sheet;

[0013] When the connecting member is stationary, the electrode sheet has a first end facing the bottom of the embedding groove when it is held in the embedding groove by the biasing force of the biasing member and a second end facing the notch of the embedding groove;

[0014] A first straight line passing through a midpoint of the first end, an axis of the hinge shaft, and a midpoint of the second end is collinear with the first axis.

[0015] Optionally, in the electrode structure, the first straight line separates the electrode sheet into a first part on the same side as the direction of the bias force applied to the electrode sheet by the bias member and a second part on the opposite side, and a groove or a hole is provided in the first part near the first end, and the center of gravity of the electrode sheet is located below the second axis and falls on the second part.

[0016] Optionally, in the electrode structure, a notch recessed toward the second end is provided on a side of the first end away from the direction in which the electrode sheet is deflected by centrifugal force;

[0017] A protrusion extending toward the notch of the embedding groove is provided on a side of the groove bottom away from the deflection direction of the electrode sheet;

[0018] When the electrode sheet is held in the embedding groove, the protrusion is adapted to abut against the notch.

[0019] Optionally, in the electrode structure, the biasing member is a torsion spring;

[0020] When the electrode sheet is held in the embedding groove, the torque applied by the torsion spring to the electrode sheet is T1;

[0021] When the connecting member rotates, the electrode sheet is deflected by an angle β due to the centrifugal force, and the torque applied to the electrode sheet by the torsion spring is T2;

[0022] Among them, T1, T2 and β satisfy the following relationship:

[0023] T2=T1+K·β (K>0, K is the torsion spring stiffness coefficient).

[0024] Optionally, in the electrode structure, the mounting portion is an annular groove circumferentially arranged on the outer wall of the connector;

[0025] The electrode comprises at least two arc-shaped, hingedly connected arc-shaped electrode sheets;

[0026] The second axis is parallel to the first axis;

[0027] When the connecting member is stationary, the arc-shaped electrode sheets are connected end to end and surround the annular groove.

[0028] Optionally, in the electrode structure, the mounting portion is a recessed area provided on an outer wall of one side of the connector, and the bottom surface of the recessed area is a plane parallel to the first axis;

[0029] The electrode comprises an electrode rod coaxially arranged with the connecting member and two connecting rods respectively hinged to the mounting portion and the electrode rod, wherein the electrode rod, the two connecting rods and the mounting portion form a four-bar linkage when the electrode rod, the two connecting rods and the mounting portion are deflected out of the mounting portion by a biasing force;

[0030] When the connecting member is stationary, the electrode rod, the two connecting rods and the mounting portion are collinear to be accommodated in the recessed area.

[0031] The second object of the present invention is to provide an electrical discharge machining device, comprising a spindle, a driving mechanism for driving the spindle to rotate and telescopically move, and an electrode structure as described in any one of the above items, wherein the connecting member is suitable for being coaxially connected to the spindle.

[0032] The third object of the present invention is to provide a processing method, comprising the following steps:

[0033] S1: First, a guide hole with a diameter larger than that of the connecting piece is processed on the workpiece to be processed, and the driving mechanism drives the connecting piece to place the electrode into the area to be processed along the axial direction of the guide hole;

[0034] S2: The driving mechanism drives the connecting member to rotate, and the electrode overcomes the biasing force under the action of centrifugal force and deflects out of the mounting portion. The electrode approaches the workpiece, and when the distance between the two reaches the discharge gap, an electric spark is generated in the discharge gap to perform discharge machining;

[0035] S3: Gradually increase the rotation speed of the connector to increase the deflection angle of the electrode until the processing of the rotary inner cavity is completed.

[0036] Preferably, in the machining method, in steps S2 and S3, if the electrode contacts the workpiece and a short circuit occurs, the discharge machining is stopped, and the rotation speed of the connector is reduced until the distance between the electrode and the workpiece reaches the discharge gap, and the discharge machining is performed again.

[0037] The technical solution of the present invention has the following advantages:

[0038] 1. The electrode structure of the present invention hinges the electrode on the connecting member with a hinge shaft and is kept in the mounting portion by the biasing force of the biasing member. The connecting member generates centrifugal force when rotating. The centrifugal force drives the electrode to overcome the biasing force and deflect out of the mounting portion, so that the electrode can extend into the guide hole processed on the workpiece when the connecting member is not rotating, and deflect out of the mounting portion to process the rotary inner cavity or inner hole when the connecting member rotates to generate centrifugal force, thereby solving the problem that the electric spark equipment in the prior art cannot process the rotary inner cavity or inner hole whose inner cavity diameter is larger than the hole mouth.

[0039] 2. The electrode structure of the present invention has a mounting portion which is an annular groove provided on the outer wall of the connector, and the electrode is a plurality of arc-shaped electrode sheets which are hingedly connected. The electrode of this structure uses the centrifugal force generated by the rotation of the connector to drive the electrode to unfold, thereby completing the processing of the cylindrical rotating inner cavity or inner hole. This allows the electrode to be creatively connected to the connector.

[0040] 3. The electrode structure of the present invention comprises an electrode rod and a connecting rod. The electrode rod, the connecting rod and the mounting portion form a four-bar structure. The electrode is creatively arranged so that the electrode can process special-shaped rotating cavities or inner holes. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A schematic diagram of the structure in which the electrode structure of the first structure in Embodiment 1 of the present invention is retained in the mounting portion;

[0043] Figure 2 This is a schematic structural diagram of the electrode structure of the first structure in Embodiment 1 of the present invention being deflected out of the mounting portion;

[0044] Figure 3 A schematic structural diagram of the deflected electrical discharge machining of the electrode structure of the first structure in Embodiment 1 of the present invention;

[0045] Figure 4It is a structural schematic diagram of the electrode structure of the first structure in Example 1 of the present invention when entering into a guide hole of a workpiece without electrical discharge machining;

[0046] Figure 5 It is a schematic structural diagram of the electrode structure of the first structure in Example 1 of the present invention during deflection discharge machining;

[0047] Figure 6 A schematic structural diagram of the electrode structure of the first structure in Embodiment 1 of the present invention during deflection discharge machining;

[0048] Figure 7 It is a schematic structural diagram of the electrode structure of the first structure in Example 1 of the present invention after deflection discharge machining is completed;

[0049] Figure 8 It is a schematic structural diagram of the electrode structure of the first structure in Example 1 of the present invention, in which the electrode is reset and stored in the mounting portion after the deflection discharge machining is completed;

[0050] Fig. 9 Schematic diagram of the structure of the electrode structure of the second structure in Example 1 of the present invention ((a) is a schematic diagram of the electrode being held in the mounting portion without electrical discharge machining; (b) is a schematic diagram of the electrode being deflected out of the mounting portion by centrifugal force during electrical discharge machining);

[0051] Fig.10 A schematic structural diagram of the deflected electrical discharge machining of the electrode structure of the second structure in Embodiment 1 of the present invention;

[0052] Fig.11 Schematic diagram of the structure of the electrode structure of the third structure in Example 1 of the present invention ((a) is a schematic diagram of the electrode being held in the mounting portion without electrical discharge machining; (b) is a schematic diagram of the electrode being deflected out of the mounting portion by centrifugal force during electrical discharge machining);

[0053] Fig.12 This is a structural schematic diagram of the deflected electrical discharge machining of the electrode structure of the third structure in Example 1 of the present invention.

[0054] Description of reference numerals:

[0055] 1-connecting member; 10-mounting portion; 11-protruding portion; 12-first axis;

[0056] 2-electrode; 21-first end; 22-second end; 23-groove (hole); 24-notch; 25-first part; 26-second part; 27-first straight line; 2a-electrode rod; 2b-connecting rod;

[0057] 3- hinge axis;

[0058] 4- Center of gravity;

[0059] 5- Second straight line;

[0060] 6-Workpiece;

[0061] 7-guide hole;

[0062] 8-discharge gap;

[0063] 9- Rotating inner cavity (rotating inner hole). DETAILED DESCRIPTION

[0064] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0065] Example 1

[0066] See also Figures 1 to 12 The present embodiment provides an electrode structure, comprising a connecting member 1, an electrode 2 and a biasing member (not shown). The connecting member 1 is a rod-shaped connecting member having a first axis 12, which can be driven to rotate around the first axis 12. One end of the connecting member 1 is specifically as follows: Figure 2 The lower end shown has a mounting portion 10. The electrode 2 is hinged to the mounting portion 10 via a hinge shaft 3, and the axis of the hinge shaft 3 is a second axis (not shown), wherein the first axis 12 and the second axis can be parallel or perpendicular. One end of the biasing member abuts against the connecting member 1, and the other end abuts against the electrode 2. The biasing member applies a biasing force to the electrode 2 that tends to remain in the mounting portion 10. That is, when the connecting member 1 is stationary, i.e., not rotating, the electrode 2 is in the mounting portion 10 under the biasing force of the biasing member, and the torque of the biasing member applied to the electrode 2 is T1. As shown in FIG. Figure 2 As shown, when the connecting member 1 is driven to rotate clockwise around the first axis 12, the electrode 2 is subjected to the centrifugal force. As the rotation speed of the connecting member 1 increases, the centrifugal force increases, and the electrode 2 overcomes the biasing force to deflect out of the mounting portion 10 and rotate clockwise around the second axis. During the rotation of the electrode 2, when the gap between the outer wall of the electrode 2 and the inner wall of the workpiece 6 reaches the discharge gap 8, the electrode 2 performs discharge corrosion processing on the workpiece 6, thereby completing the processing of the rotary inner cavity or inner hole. It should be noted that the discharge gap 8 in this embodiment varies according to factors such as the processing voltage and pulse parameters. The larger the processing voltage, the larger the discharge gap, preferably between 1 micron and 20 microns.

[0067] Specifically, the mounting portion 10 is provided on the connecting member 1 along the first axis 12 and facing away from the electrode 2. Figure 3 The upwardly recessed bezel shown, such as Figure 3As shown, the embedding groove is arranged in the middle of the lower end of the connecting member 1 and extends upward, and the embedding groove is formed with openings on both sides of the deflection direction of the electrode 2, that is, the left and right sides of the embedding groove are openings, so that the electrode 2 can be deflected out of the mounting portion 10. Correspondingly, the electrode 2 is a sheet-shaped electrode sheet, and the axis of the hinge shaft 3, that is, the second axis, is perpendicular to the axis of the connecting member 1, that is, the first axis 12, and the hinge shaft 3 is hinged in the middle of the electrode sheet.

[0068] More specifically, for the electrode sheet, Figure 1 and Figure 2 As shown, when the electrode sheet is held in the embedded groove by the biasing force of the biasing member, the bottom of the groove is facing the embedded groove, that is, Figure 1 The first end 21 of the upper end and the notch toward the embedding groove are also shown as Figure 1 The second end 22 of the lower end is shown. Figure 1 As shown, when the connector 1 is stationary and the electrode 2 is kept in the embedded groove, the first straight line 27 passing through the midpoint of the first end 21, the axis of the hinge shaft 3 and the midpoint of the second end 22 is collinear with the first axis 12, and the electrode sheet is kept in the embedded groove by the biasing force. In order to facilitate the deflection of the electrode sheet by the centrifugal force, the electrode sheet is preferably designed as an eccentric electrode sheet, and its center of gravity 4 should be located below the second axis and on the right side of the electrode sheet, that is, on the side of the deflection direction of the second end 22 of the electrode sheet. More specifically, as Figure 1 As shown, the first straight line 27 divides the electrode sheet into a first part 25 in the left half and a second part 26 in the right half. The center of gravity 4 of the electrode sheet is located below the second axis and falls on the second part 26. Specifically, the center of gravity 4 of the electrode sheet is located as shown in FIG. Figure 1 The lower right side of the electrode sheet shown, that is, the center of gravity of the electrode sheet is located on one side of the deflection direction of the lower half of the electrode sheet. For the convenience of distinguishing the description, the line connecting the center of the hinge shaft 3 and the center of gravity 4 of the electrode sheet is the second straight line 5, and the second straight line 5 is set at an angle α with the first straight line 27, and the angle α is an acute angle less than 90°. More specifically, in order to enable the center of gravity of the electrode sheet to be eccentric and located on the right side of the lower half of the electrode sheet, a groove portion 23 or a hole portion 23 is provided on the first part 25 of the electrode sheet near the first end 21, and the groove portion 23 or the hole portion 23 is arranged near the first straight line 27. The size of the groove portion 23 or the hole portion 23 is not described and limited in detail here, and those skilled in the art can select and design it according to the required eccentric distance. The shape can be selected as square, circular or other special shapes, as long as the electrode sheet can be formed into an eccentric electrode sheet. Furthermore, in order to enable the electrode sheet to remain in the mounting portion 10 when the connector is stationary, the side of the first end 21 of the electrode sheet away from the deflection direction, that is, as shown in FIG. Figure 1The right side is shown with a notch 24 extending concavely toward the second end 22. Correspondingly, a protrusion 11 extending toward the notch, that is, extending downward, is provided at the bottom of the embedded groove. When the electrode sheet is held in the embedded groove by the biasing force, the protrusion 11 abuts against the notch 24. It should be noted that the protrusion 11 is located at the front end of the biasing force direction, thereby limiting the electrode sheet and ensuring that the electrode sheet can always be held in the embedded groove by the biasing force. The electrode sheet of this embodiment is suitable for processing a spherical rotating inner cavity or inner hole.

[0069] It should be noted that if Figure 2 As shown, the biasing member is a conventional torsion spring. When the connecting member 1 is driven to rotate clockwise around the first axis 12, the electrode sheet is deflected to the left at its upper part and to the right at its lower part by the centrifugal force. When the electrode sheet deflects by an angle β, that is, the first straight line 27 forms an angle β with the first axis 12, the torque applied by the torsion spring to the electrode sheet is T2, and the direction is clockwise, wherein T1, T2 and β satisfy the following relationship:

[0070] T2=T1+K·β (K>0, K is the torsion spring stiffness coefficient).

[0071] It should be noted that, during the rotation of the electrode sheet under the centrifugal force, the torque applied to the electrode sheet by the torsion spring, the torque applied to the electrode sheet by gravity, and the torque applied to the electrode sheet by the centrifugal force are in balance.

[0072] It can be seen from the above relationship that when the speed of the connecting member 1 is higher, the centrifugal force is greater, the torque applied to the electrode sheet by the torsion spring is greater, and β is also greater. Therefore, when the electrode sheet rotates around the second axis for discharge machining, it is necessary to complete the machining of the rotary cavity or hole, and it is only necessary to gradually increase the speed of the connecting member 1, so that the deflection angle β of the electrode sheet gradually increases, so as to complete the discharge machining of the entire rotary inner cavity or inner hole.

[0073] As an alternative embodiment, Fig. 9 and Fig.10As shown, the first axis 12 and the second axis can also be arranged in parallel, and the mounting portion 10 is an annular groove circumferentially arranged on the outer wall of the connector. Correspondingly, the electrode 2 is composed of a plurality of arc-shaped arc electrode sheets that are hingedly connected. In this embodiment, the electrode includes three arc electrode sheets hingedly connected by hinges, and the three arc electrode sheets can just enclose a cylinder that is compatible with the annular groove, one of the arc electrode sheets is hinged in the annular groove through a hinge, and the hinge 3 of each arc electrode sheet is parallel to the first axis 12. When the connector 1 is stationary, the arc electrode sheets are connected end to end and surround the annular groove. It should be noted that there is no connection between the other two arc electrode sheets and the connector 1. In other words, when the connector 1 rotates around the first axis 12, the electrode 2 is unfolded by the centrifugal force. Optionally, a protrusion or groove may be provided at one end of the arc-shaped electrode sheet away from the arc-shaped electrode sheet hinged to the annular groove and spliced ​​with the arc-shaped electrode sheet hinged to the annular groove, and the corresponding arc-shaped electrode sheet hinged to the annular groove is provided with a matching groove or protrusion. Fig.11 As shown, the electrode sheet of this embodiment can be processed into a cylindrical rotating inner cavity or inner hole.

[0074] As another alternative embodiment, Fig.11 and Fig.12 As shown, the mounting portion 10 is a recessed area opened on the outer wall of one side of the connecting member 1, and the bottom surface of the recessed area is a plane parallel to the first axis 12. The second axis is perpendicular to the first axis. Correspondingly, the electrode 2 includes an electrode rod 2a coaxially arranged with the connecting member 1 and two connecting rods 2b respectively hinged to the mounting portion 10 and the electrode rod 2a. When the electrode rod 2a, the two connecting rods 2b and the mounting portion 10 are deflected out of the mounting portion 10 by the biasing force, a four-bar linkage is formed. More specifically, the two connecting rods 2b are arranged in parallel one above and one below, and the left end of each connecting rod 2b is hinged to the mounting portion 10 through a hinge shaft 3, and the right end is hinged to the electrode rod 2a through a hinge shaft 3, wherein the right end of the lower connecting rod 2b is hinged to the lower end of the electrode rod 2a, and the right end of the upper connecting rod 2b is hinged to the upper end of the electrode rod 2a but not the end, that is, a part of the upper end of the electrode rod 2a does not form a quadrilateral of the four-bar linkage. When the connector 1 is stationary, the electrode rod 2a, the two connecting rods 2b and the mounting portion 10 are collinear to be accommodated in the recessed area. That is, the center line of the electrode rod 2a, the center line of the connecting rod 2b and the center line of the mounting portion 10 are collinear and parallel to the first axis 12, so that when the connector 1 is stationary, the electrode 2 is kept in the mounting portion 10 by the biasing force. Fig.12 As shown, the electrode in this embodiment can be used to process irregular rotational cavities or holes.

[0075] Example 2

[0076] The electric discharge machining device of this embodiment is as follows Figures 1 to 12As shown, it includes a spindle (not shown), a driving mechanism (not shown) and an electrode structure of Example 1. The connecting member 1 and the spindle are coaxially arranged, and the spindle and the driving mechanism are connected. The connecting member 1 is driven by the driving mechanism to rotate, so that the electrode 2 overcomes the biasing force of the biasing member under the action of centrifugal force and deflects out of the mounting portion 10, and generates electric sparks to perform discharge machining on the workpiece 6 when the gap between the workpiece 6 reaches the discharge gap. The driving mechanism includes a rotating motor for driving the spindle to rotate and a lifting mechanism for driving the spindle to rise and fall. The lifting direction of the lifting mechanism is along the axial direction of the spindle and the connecting member 1. The specific structure and working principle of the driving mechanism are not described and limited in detail here, and are conventional mechanisms. Of course, a discharge power supply is also included. The discharge power supply adopts the discharge power supply commonly used in existing ordinary electric spark equipment, which is not described and limited in detail.

[0077] Example 3

[0078] This embodiment provides a processing method, see Figures 1 to 12 , based on the electrical discharge machining device in the above-mentioned embodiment 2, comprising the following steps:

[0079] S1: First, a guide hole 7 having a diameter larger than that of the connecting piece is processed on the workpiece 6 to be processed, and the driving mechanism drives the connecting piece 1 along the axial direction of the guide hole 7, that is, Figure 4 Place the electrode 2 into the area to be processed in the direction of the downward arrow shown;

[0080] S2: The driving mechanism drives the connecting member 1 to rotate, and the electrode 2 overcomes the biasing force under the action of centrifugal force and deflects out of the mounting portion 10, and the electrode 2 approaches the inner wall of the guide hole 7 of the workpiece 6. When the distance between the electrode 2 and the inner wall of the guide hole 7 reaches the discharge gap 8, an electric spark is generated in the discharge gap 8 to perform discharge machining;

[0081] S3: gradually increase the rotation speed of the connector 1 to increase the deflection angle of the electrode 2 until the processing of the rotary inner cavity is completed.

[0082] It should be noted that in steps S2 and S3, if the electrode 2 contacts the workpiece 6 and a short circuit occurs, causing the EDM equipment to stop discharge machining, the rotation speed of the connector 1 should be reduced, that is, the rotation speed of the spindle should be reduced, until the distance between the electrode 2 and the workpiece 6 reaches the discharge gap, and an EDM is generated between the electrode 2 and the workpiece 6 for discharge machining again.

[0083] It should be noted that the rotation speed of the connecting member 1 gradually increases from zero. The purpose is that, as can be seen from the relationship in Example 1, the greater the rotation speed of the connecting member 1, the greater the deflection angle of the electrode 2. Therefore, setting the rotation speed of the connecting member 1 to gradually increase can avoid the deflection angle of the electrode 2 being too large, causing the electrode 2 to contact the workpiece 6 and cause a short circuit or abnormal discharge.

[0084] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An electrode structure, characterized in that: include: A connecting member (1), the axis of which is a first axis, and one end of the connecting member (1) is provided with a mounting portion (10); The electrode (2) is hinged to the mounting portion (10) via a hinge shaft (3), and the axis of the hinge shaft (3) is a second axis; A biasing member, one end of which abuts against the connecting member (1) and the other end of which abuts against the electrode (2), and applies a biasing force to the electrode (2) tending to be retained in the mounting portion (10); The connecting member (1) can be driven to rotate around the first axis, and when the connecting member (1) rotates, the electrode (2) is acted upon by centrifugal force to overcome the biasing force and deflect out of the mounting portion (10) and rotate around the second axis; The mounting portion (10) is an embedding groove provided on the connecting member (1) and recessed along the first axis and away from the electrode (2); the embedding groove is located on both sides of the deflection direction of the electrode (2) and has openings for the electrode (2) to deflect; The electrode (2) is a sheet-shaped electrode sheet, the second axis is perpendicular to the first axis, and the hinge shaft (3) is hinged at the middle of the electrode sheet; When the connecting member (1) is stationary, the electrode sheet has a first end (21) facing the bottom of the embedding groove when it is held in the embedding groove by the biasing force of the biasing member, and a second end (22) facing the notch of the embedding groove; A first straight line (27) passing through the midpoint of the first end (21), the axis of the hinge shaft (3) and the midpoint of the second end (22) is collinear with the first axis; The first straight line (27) separates the electrode sheet into a first portion (25) on the same side as the biasing force applied by the biasing member to the electrode sheet and a second portion (26) on the opposite side, a groove portion or a hole portion is provided in the first portion (25) near the first end (21), and the center of gravity of the electrode sheet is located below the second axis and falls on the second portion (26).

2. The electrode structure according to claim 1, characterized in that: A notch (24) recessed toward the second end (22) is provided on a side of the first end (21) that is away from the direction in which the electrode sheet is deflected by centrifugal force; A protrusion (11) extending toward the notch of the embedding groove is provided on the side of the groove bottom facing away from the deflection direction of the electrode sheet; When the electrode sheet is held in the embedding groove, the protruding portion (11) is suitable for abutting against the notch (24).

3. The electrode structure according to claim 1 or 2, characterized in that: The biasing member is a torsion spring; When the electrode sheet is held in the embedding groove, the torque applied by the torsion spring to the electrode sheet is T1; When the connecting member (1) rotates, the electrode sheet is deflected by an angle β due to the centrifugal force, and the torque applied to the electrode sheet by the torsion spring is T2; Among them, T1, T2 and β satisfy the following relationship: T2=T1+K·β; wherein K>0, and K is the torsion spring stiffness coefficient.

4. An electrical discharge machining device, characterized in that: It comprises a main shaft, a driving mechanism for driving the main shaft to rotate and telescopically move, and the electrode structure according to any one of claims 1 to 3, wherein the connecting member (1) is suitable for being coaxially connected to the main shaft.

5. A method for machining a rotary inner cavity using an electric discharge machining device, wherein the electric discharge machining device is the electric discharge machining device according to claim 4, characterized in that: The following steps are involved: S1: First, a guide hole (7) having a diameter larger than that of the connecting member is machined on the workpiece to be machined, and a driving mechanism drives the connecting member to place the electrode (2) into the area to be machined along the axial direction of the guide hole (7); S2: The driving mechanism drives the connecting member (1) to rotate, and the electrode overcomes the biasing force under the action of centrifugal force and deflects out of the mounting portion (10), and the electrode (2) approaches the workpiece (6). When the distance between the two reaches the discharge gap, an electric spark is generated in the discharge gap (8) to perform electric discharge machining; S3: gradually increasing the rotation speed of the connecting member (1) to increase the deflection angle of the electrode (2) until the processing of the rotary inner cavity is completed.

6. The processing method according to claim 5, characterized in that: In steps S2 and S3, if the electrode (2) contacts the workpiece and a short circuit occurs, the discharge machining is stopped, and the rotation speed of the connector (1) is reduced until the distance between the electrode (2) and the workpiece (6) reaches the discharge gap, and the discharge machining is performed again.

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