JP2003340649A - Electrochemical machining tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrochemical machining tool which prevents the surface of an aligning part from getting flawed or worn by an alining sphere or the like and from deforming due to pressure by the sphere or the like and has both the alining part and a tool electrode resistant to corrosion by an electrolyte. <P>SOLUTION: A base material 12 of the aligning part A2 and the tool A1 is a unit made of quenched and tempered alloy steel with hardness of Hv 700 or higher. A corrosion-resistant conductive ceramic coating layer 14 is provided on the surface of the base material 12, and an abrasion/corrosion resistant electrically insulating ceramic coating layer 16 with hardness of Hv 1,500 or higher is stacked thereon. The ceramic coating layer 16 on the top of a herring- bone-like protrusion 10 formed on the outer periphery of the tool A1 is ground to be removed, thereby exposing the conductive ceramic coating layer 14 to provide the tool electrode 18. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic machining tool useful for electrolytically machining an inner peripheral surface portion or an outer peripheral surface portion of a cylindrical surface, and more particularly, to enhance the dynamic pressure of a lubricating fluid in a radial dynamic pressure bearing. The present invention relates to an electrolytic machining tool useful for forming a dynamic pressure groove portion on the inner peripheral surface of the sleeve, the outer peripheral surface of the shaft body, or the like.

[0002]

2. Description of the Related Art When a groove for dynamic pressure for increasing the dynamic pressure of a lubricating fluid in a radial dynamic pressure bearing is formed on the inner peripheral surface of a sleeve by electrolytic machining, the outer peripheral surface is a cylindrical surface. An electrolytic machining tool having a tool electrode can be used. In order to accurately form a groove for dynamic pressure of a desired depth and width on the inner peripheral surface of the sleeve using such an electrolytic machining tool, in order to adjust the axis line of the electrolytic machining tool and the axis line of the sleeve in a predetermined relationship. May be aligned. Normally, by aligning the axis line of the electrolytic machining tool and the axis line of the sleeve, the tool electrode in the electrolytic machining tool and the inner peripheral surface of the sleeve are aligned so that the gap between the tool electrode and the inner peripheral surface of the sleeve is aligned. Is set to be constant, so that the depth and the width of the dynamic pressure groove portion are formed to be constant.

Means for realizing such alignment are shown in FIGS. 3 to 6.

An annular support 20 made of an electrically insulating material
Through the upper and lower through holes 20a of the tool part A of the electrolytic machining tool A
1 and the centering portion A2 are arranged so as to project upward. The electrolytic processing tool A includes a cylindrical tool portion A1 and an aligning portion A2, which has a right circular cone shape and a tip portion formed in a convex curved surface, and is coaxially and integrally formed. A herringbone-shaped tool electrode portion 18 is provided on the outer peripheral portion of the tool portion A1, and the centering portion A2 is provided.
Is located above the tool part A1.

A sleeve member 22 for a dynamic pressure bearing, which is a workpiece, is placed on the horizontal upper surface of the annular support 20 at its lower end face with its axis oriented in the vertical direction. The movable unit 26 including the pressing plate 24 and the centering mechanism B in a state where the centering portion A2 and the tool portion A1 of A are inserted inside the cylindrical inner peripheral surface of the sleeve member 22 is arranged at a predetermined position shown in FIG. By pressing down to 2
The lower surface of 4 presses the upper surface of the sleeve member 22, and the inner peripheral surface of the sleeve member 22 and the tool portion A1 of the electrolytic processing tool A are aligned. Tool electrode part 18 of tool part A1
Faces the lower inner peripheral surface of the sleeve member 22.

The centering mechanism B comprises a centering pressing member B1, a sphere holding member B2 and a centering sphere B3. An axial groove portion B1a having a radially outward opening is provided at a lower end portion of the centering presser member B1 for each 120 ° center angle in a plan view, and the lower end portion of each axial groove portion B1a is in an open state. Centering presser member B
1, a sphere holding member B2 is fitted and fixed, and three electrically insulating centering spheres B3 made of ceramic and having the same diameter are arranged between the sphere holding member B2 and the centering pressing member B1. ing.

The spherical body holding member B2 has a central insertion hole B2a through which the centering portion A2 of the electrolytic processing tool A is inserted and a plan view 120.
Three spherical body holding holes B2b provided for each central angle, and a fitting projection projecting between the spherical body holding holes B2b and fitted and fixed from below into the axial groove portion B1a of the aligning pressing member B1. B
2c and. Each sphere holding hole B2b has a centering sphere B.
3 is held in a state of being slightly movable in the radial direction.

The movable unit 26 is lowered to adjust the centering portion A2.
The centering sphere B3 is brought into contact with the outer peripheral surface of the centering portion A2 by inserting the centering hole B2a of the sphere holding member B2. When the movable unit 26 is sufficiently lowered, each of the aligning spheres B3 is pushed radially outward by the outer peripheral surface of the aligning portion A2 and abuts on the inner peripheral surface of the sleeve member 22 as well. Both the outer peripheral surface of the centering portion A2 and the inner peripheral surface of the sleeve member 22 are pressed by the pressure. As a result, FIG.
As shown in FIG. 7, the distances from the axial center position of the aligning portion A2 to the centers of the aligning spheres B3 are all equal, so that the axial center line of the sleeve member 22 and the axial center of the aligning portion A2 and the tool portion A1. The lines will match.

Such an electrolytically processed tool A is made of stainless steel (SUS-420J2) that has been hardened to a hardness of about Hv700 to improve its wear resistance. The thing which removed the electrodeposition coating of the part of the bone-shaped tool electrode part 18 was used. However, when it is repeatedly used, the centering portion A2 made of hardened stainless steel is easily worn by the centering sphere B3 made of ceramic, so that the centering accuracy is greatly lowered in a relatively short period of time. Further, since the adhesion between the stainless steel and the coating film by electrodeposition coating is relatively low, the coating film is liable to come off and cannot be used in a relatively short period of time.

In normal electrolytic processing, the tool electrode portion, which is a portion through which an electrolytic current flows, is used as it is (without a coating film or the like), but a large number of dynamic pressure groove portions are formed to increase the dynamic pressure of the lubricating fluid. Repeatedly for the sleeve member and shaft member of
It is easy for the tool electrode portion to be damaged and the machining accuracy of the dynamic pressure groove portion to be reduced. Therefore, in order to industrially mass-produce the dynamic pressure bearing by forming the groove for dynamic pressure with the electrolytic processing tool, it is desired to protect the tool electrode portion and prolong the life of the electrolytic processing tool.

The present invention has been made in view of the above problems existing in the prior art, and an object of the present invention is to prevent the surface of the centering portion from being damaged or worn by a centering sphere or the like. Electrolysis machining tool, which is prevented from occurring, and is prevented from being deformed due to the pressing force of the centering sphere, etc., and the centering part or the centering part and the tool electrode part have corrosion resistance to an electrolytic solution, and a tool. An object of the present invention is to provide an electrolytic machining tool in which an electrode portion has corrosion resistance to an electrolytic solution.

[0012]

The electrolytic machining tool of the present invention which achieves the above object has a continuous rotational symmetry around a constant axis and a reduction in diameter continuously toward one of the axial directions. An electrolytic machining tool comprising a centering portion having a diameter outer peripheral surface portion or a diameter-reduced inner peripheral surface portion, and a tool portion located on an extension of the axis line and exposing a tool electrode portion on the surface, The aligning portion has at least a quenched steel having a hardness of Hv 700 or more as a base material, and has an electrically insulating ceramic coating layer having a hardness of Hv 1500 or more with wear resistance and corrosion resistance on the surface. The tool part is to expose the tool electrode part in an insulating part whose surface is coated with an electrically insulating ceramic coating layer having corrosion resistance, and the tool electrode part has corrosion resistance. Equipped with conductivity Characterized in that the surface by La electrochromic coating layer is made is coated.

The centering portion of this electrolytic machining tool has a continuous rotational symmetry about a fixed axis line, and has a radially reduced outer peripheral surface portion or a radially reduced inner periphery which continuously reduces in diameter toward one of the axial directions. Since the surface portion is provided, for example, in a state in which at least three aligning spheres having the same diameter are held at predetermined positions in the circumferential direction by holding members or the like, the aligning spheres are respectively reduced in diameter outer peripheral surface portion or By bringing the reduced-diameter inner peripheral surface portion into contact with the inner peripheral surface or the outer peripheral surface of the workpiece, the tool portion located on the extension of the axis line and the workpiece can be aligned.

The aligning portion is made of H, which has abrasion resistance and corrosion resistance.
Since it has an electrically insulating ceramic coating layer with a hardness of v1500 or more on its surface, the surface of the outer peripheral surface of the reduced diameter or the inner peripheral surface of the reduced diameter may be scratched or worn by the aligning sphere, or corroded by the electrolytic solution. Is prevented. Further, since the base material of the aligning portion is a sufficiently hard steel having a hardness of Hv 700 or more, it is possible to prevent deformation due to the pressing force of the aligning sphere or the like. Therefore, even if a ceramic sphere that is sufficiently hard and has good wear resistance and corrosion resistance to an electrolytic solution is used as the centering sphere, it is possible to prevent the alignment from being misaligned as described above. Be done. Moreover, since the ceramic coating and the base material have high adhesion, the electrically insulating ceramic coating layer has excellent durability. As a result, the life of the aligning portion is extended.

On the other hand, the tool part exposes the tool electrode part in an insulating part whose surface is coated with an electrically insulating ceramic coating layer having corrosion resistance, and the tool electrode part has corrosion resistance. The surface is coated with a conductive ceramic coating layer, and the electrically insulating ceramic coating layer that covers the surface of the insulating portion and the conductive ceramic coating layer that covers the surface of the tool electrode portion are both electrolytic solutions. Since it has corrosion resistance to, the tool part has a long life. Further, when the dynamic pressure groove is formed and used for industrial mass production of the dynamic pressure bearing, the tool electrode part is protected by the conductive ceramic coating layer, so that the machining accuracy of the dynamic pressure groove is deteriorated. Can be prevented.

As described above, since the aligning portion and the tool portion both have a long service life, the service life of the electrolytic processing tool as a whole is extended.

Another electrolytic machining tool of the present invention is an electrolytic machining tool having a tool part exposing a tool electrode part on the surface, wherein the tool part is an electrically insulating ceramic coating layer having corrosion resistance. In the insulating portion whose surface is coated with, the tool electrode portion is exposed, and the tool electrode portion has a surface coated with a conductive ceramic coating layer having corrosion resistance. And This electrolytic processing tool does not require an aligning portion.

Still another electrolytic machining tool according to the present invention has a diameter-reduced outer peripheral surface portion or a diameter-reduced outer peripheral surface portion which has a continuous rotational symmetry around a constant axis and which is continuously reduced in diameter toward one of the axial directions. An electrolytic machining tool comprising a centering part having a peripheral surface part and a tool part located on an extension of the axis line and exposing a tool electrode part on the surface, wherein the centering part has a hardness. Is Hv 700 or more as a base material and has an electrically insulating ceramic coating layer of Hv 1500 or more having wear resistance and corrosion resistance on the surface.

The diameter-reduced outer peripheral surface portion or the diameter-reduced inner peripheral surface portion of the aligning portion has continuous rotational symmetry (symmetric about rotation at an arbitrary angle) about a constant axis and is continuous toward one side in the axial direction. The diameter. Examples of such a reduced diameter outer peripheral surface portion or a reduced diameter inner peripheral surface portion include a right circular cone side peripheral surface such as a right circular cone outer peripheral surface portion and a funnel-shaped right circular cone inner peripheral surface portion, or a right circular truncated cone side peripheral surface portion. The outer peripheral surface portion or the inner peripheral surface portion can be mentioned.

The base material of the aligning portion is at least a quenched steel having a hardness of Hv 700 or more. Hardened and tempered, and whose hardness hardly decreases even when heated to about 500 ° C or 50
It is preferable that the material is secondly cured when heated to about 0 ° C. to prevent a decrease in hardness. An electrically insulating ceramic coating layer having a hardness of Hv1500 or more (for example, a thickness of 5 to 10) having abrasion resistance and corrosion resistance to an electrolytic solution is provided on the surface of the centering portion whose base material is hardened steel.
This is because the temperature of the base material can be about 500 ° C. when (μm) is provided by means such as that described later.

The steel used as the base material of the aligning portion is preferably 0.3 to 2.5% by weight of C and 3.0 to 20.0.
An alloy steel containing Cr by weight, 0.5 to 1.5% by weight Mo, and one or both of 0.1 to 0.5% by weight V, and the balance being iron and inevitable impurities.
Both P and S that can be contained as impurities are 0.03% by weight or less.

The reasons for limiting the composition and content of this alloy steel are as follows.

C: Required hardness Hv if less than 0.3% by weight
700 cannot be secured. Even if the content exceeds 2.5% by weight, the hardness does not increase so much, but the corrosion resistance is adversely affected. C is also a deoxidizing element, but for that purpose << Note: 0.3 wt%? 》 It is enough if it is added. A more preferable C content in the alloy steel is 0.5 to 2.0% by weight.

Cr: Has a function of enhancing corrosion resistance, and in order to obtain its effect, it must be contained in an amount of 5% by weight or more. Even if the content exceeds 20% by weight, the effect is saturated and the cost becomes high, so this value is made the upper limit. The more preferable Cr content in the alloy steel is 5 to 10% by weight.

Mo: Improves the hardenability and, in particular, at the time of tempering treatment after quenching, causes secondary hardening to prevent the decrease in hardness. In order to obtain this effect, 0.5% by weight or more is necessary, and even if it exceeds 1.5% by weight, the effect is saturated.

V: Improves the hardenability, and particularly during the tempering treatment after quenching, secondary hardening occurs to prevent the decrease in hardness. To obtain this effect, 0.1% by weight or more is necessary, and even if it exceeds 0.5% by weight, the effect is saturated.

Mo, V or W described later is contained in order to prevent a decrease in hardness of the alloy steel when heated to about 500 ° C.

P and S: both are impurity elements, and 0.0
If the content is 3% by weight or more, the toughness will be adversely affected.
It must be less than this.

This alloy steel, which has been hardened or hardened and tempered and has a hardness of Hv 700 or more, is 50
When it is heated to about 0 ° C., it is secondarily hardened to prevent the decrease in hardness.

In the alloy steel, a part or all of the above 0.5 to 1.5% by weight of Mo is replaced by W in an amount twice as much as that of Mo, and (Mo + 0.5W) in the alloy steel is added. The content may be 0.5 to 1.5% by weight.

The reason for using W in the above content is as follows.

W: Improves hardenability, and particularly during tempering treatment after quenching, causes secondary hardening to prevent the hardness from lowering. In order to obtain this effect, 0.5% by weight or more is necessary, and even if it exceeds 1.5% by weight, the effect is saturated. As an alloying element, it has properties similar to Mo, and by adding twice the amount of Mo in terms of weight%, almost the same effect can be obtained.

The alloy steel further comprises 0.05 to 0.5% by weight of Si, 0.1 to 0.6% by weight of Mn,
0.1 to 2.0 wt% Cu, and 0.1 to 2.0
It may contain one kind or two or more kinds of Ni by weight.

The reason why Si, Mn, Cu, and Ni are used in the above contents is as follows.

Si: Si is a deoxidizing element, and for that purpose, 0.05% by weight or more is necessary. If added excessively, the toughness is impaired, so the content is made 0.5% by weight or less.

Mn: Mn fixes the impurity S in the form of MnS and improves toughness. From this point of view, 0.1% by weight or more is necessary, but if it is contained in excess of 0.6% by weight, no further preferable effect can be obtained. Mn is also a strengthening element, but in the alloy steel of the present invention, Cr and Mo (or V,
(W etc.) can sufficiently enhance the hardenability,
Addition for this purpose is not always necessary. Mn is also a deoxidizing element, but is also a deoxidizing element such as C or S.
When i is added at the minimum, deoxidation is not hindered even if i is not added.

Cu: Not only enhances the hardenability, but also partly precipitates during tempering to mitigate the decrease in hardness. To improve hardenability, 0.1 wt% or more is added.
When utilizing precipitation strengthening during tempering, 0.7 wt% or more is contained. If it exceeds 2% by weight, the effect is saturated.

Ni: As a component of the alloy steel in the present invention, it mainly has an effect of enhancing toughness. For this purpose, it is necessary to add 0.1% by weight or more. Also, Cu
Ni has the effect of suppressing Cu cracking that occurs when Ni is added, but for this purpose, the amount of Ni added is 1/2 or more of the amount of Cu added.
May be added. If it is 2% by weight or more, the effect of improving toughness is saturated.

The tool portion of the electrolytically machined tool of the present invention (including those having an aligning portion and those not having an aligning portion) has an insulating portion (for example, a thickness) whose surface is coated with an electrically insulating ceramic coating layer having corrosion resistance. 5 to 10 μm) to expose the tool electrode part, and the tool electrode part has a surface coated with a conductive ceramic coating layer (for example, a thickness of 3 to 5 μm) having corrosion resistance. is there. The electrically insulating ceramic coating layer that covers the surface of the insulating portion in the tool portion has the same hardness as that of the aligning portion, which has wear resistance and corrosion resistance and has a hardness of H.
An electrically insulating ceramic coating layer of v1500 or more can be used.

The tool part has a conductive ceramic coating layer having corrosion resistance on the surface of the base material, and the tool electrode part has a part of the conductive ceramic coating layer on the surface of the tool part. The insulating part may be formed by laminating an electrically insulating ceramic coating layer having corrosion resistance on the remaining part of the conductive ceramic coating layer in the tool part.

In such a tool electrode part, for example, a conductive ceramic coating layer having corrosion resistance is provided on the surface of a base material, and an electrically insulating ceramic coating layer having corrosion resistance is laminated on the layer. Forming a tool electrode part in the insulating part by exposing a part of the electrically conductive ceramic coating layer on the surface by removing the necessary parts of the electrically insulating ceramic coating layer by, for example, polishing or other means. You can Alternatively, for example, a conductive ceramic coating layer having corrosion resistance is provided on the surface of the base material, and an electrically insulating ceramic having corrosion resistance is provided on a portion of the conductive ceramic coating layer other than the portion where the tool electrode portion is formed. The tool electrode portion can also be exposed and formed in the insulating portion by stacking the coating layers. The shape and size of the tool electrode is
The shape and size of the intended electrolytic processing (for example, dynamic pressure) should be determined.

Electrical insulation in the aligning part and the tool part
The ceramic coating layer is Al _TwoO_Three, Si
_ThreeN_Four, Or a diamond-like carbon thin film
Preferably. Also, in the aligning section and the tool section,
Electrically insulating ceramic coating layer has a specific electrical resistance
Is 5 × 10¹⁴Ω · cm or more is preferable
Good

The electrically insulating ceramic coating layer can be formed by using, for example, a plasma CVD method or a PVD method. When the electrically insulating ceramic coating layer is provided by such means, the temperature of the base material is 50
It can be as low as 0 ° C.

The conductive ceramic coating layer having corrosion resistance in the tool part (or the tool part and the centering part) may be made of transition metal carbide, transition metal nitride or transition metal carbonitride. In addition, this conductive ceramic coating layer with corrosion resistance is made of TiN,
1 or 2 of TiAlN, TiCN, NbN, and CrN
It is preferable that the above is formed. The conductive ceramic coating layer is formed, for example, by plasma CVD.
Method or PVD method can be utilized. When the conductive ceramic coating layer is provided by such means, the temperature of the base material may be about 500 ° C.

The electrolytic machining tool of the present invention has two tool parts.
It is also possible to provide it at one or more places, and it is also possible to provide two or more aligning parts. It is preferable that the plurality of tool portions are provided coaxially. Centering part 2
When provided in one place, one aligning portion is provided with a reduced diameter outer peripheral surface portion or a reduced diameter inner peripheral surface portion that continuously reduces diameter toward one in the axial direction, and the other aligning portion is directed toward the other in the axial direction. It is preferable that the diameter-reduced outer peripheral surface portion or the diameter-reduced inner peripheral surface portion that continuously reduces in diameter is provided coaxially with the one alignment portion.

In the electrolytic machining tool of the present invention provided with an aligning portion and a tool portion, the tool portion is located on an extension of the axis of the aligning portion, and the tool portion and the aligning portion are The axes are preferably coincident. Further, it is preferable that the tool portion and the aligning portion are integrated in order to realize high aligning accuracy and enhance the accuracy of electrolytic processing to improve the quality of the processed product. On the other hand, if the tool part and the centering part are provided separately, and a male screw part and a female screw part are provided on each, and they are screwed together, for example, they can be attached and detached using a fastening means. Since only the one that causes inconvenience such as damage or damage can be replaced and used, the overall cost can be reduced. Further, by forming the tool electrode separately from the aligning portion, it is possible to facilitate the production of the tool electrode in the tool portion. The tool part may use a base material of the same material as the centering part as the base material, but the base material is not necessarily limited to this.

Therefore, the electrolytic processing tool of the present invention is, for example,
The base material of the aligning portion and the tool portion is an integral body made of at least hardened steel having a hardness of Hv 700 or more, and the surface of the base material in the aligning portion and the tool portion is electrically conductive with corrosion resistance. A conductive ceramic coating layer, the tool electrode portion is a part of the conductive ceramic coating layer in the tool portion is exposed on the surface, on the conductive ceramic coating layer in the alignment portion. Hardness with abrasion resistance and corrosion resistance is Hv150
Zero or more electrically insulating ceramic coating layers are laminated to form the surface of the centering portion, and abrasion resistance and corrosion resistance are provided on the rest of the conductive ceramic coating layer in the tool portion. An electrically insulating ceramic coating layer having a hardness of Hv 1500 or more may be laminated to form the insulating portion. In this case, since the base material of the centering part and the tool part are integrated, higher centering accuracy is achieved compared with the case where separate centering part and tool part are combined, and the accuracy of electrolytic processing is increased, and the processed product Can improve the quality of.

In each of the electrolytic machining tools described above, the radial dynamic pressure bearing is provided with respect to the inner peripheral surface of the sleeve body or the outer peripheral surface of the shaft body of the sleeve body and the shaft body for forming the radial dynamic pressure bearing. Can be used to form a dynamic pressure groove portion for increasing the dynamic pressure of the lubricating fluid interposed between the sleeve body and the shaft body.

[0049]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic front view of an example of an embodiment of an electrolytic machining tool of the present invention.

In this electrolytic processing tool A, the upper portion of the cylindrical portion is used as the tool portion A1, and the aligning portion A2 is coaxially projected from the upper surface of the cylindrical portion. On the outer peripheral surface of the tool part A1,
A herringbone-shaped ridge 10 having a rectangular cross section is provided over the entire circumference in the circumferential direction. FIG. 2 is an enlarged schematic cross-sectional view of a main part orthogonal to the herringbone-shaped ridge 10 in the tool part A1 of FIG. Herringbone-shaped ridge 10
The height h of the ridges 10 may be, for example, about 40 μm, and the interval between the protrusions 10 may be, for example, about 20 to 40 μm. The top surface 10a of each herringbone-shaped ridge 10 is formed along a cylindrical outer peripheral surface centered on the axis of the electrolytic processing tool A.

The aligning portion A2 has a base portion having a cylindrical shape and an upper portion thereof has a right circular cone shape having a convex curved end.
The outer peripheral surface of the right conical portion constitutes a diameter-reduced outer peripheral surface portion whose diameter is continuously reduced upward in the axial direction.

The base material 12 of the electrolytically processed tool A is an alloy tool steel SKD11 specified in JIS G4404 and has a hardness of Hv700 by quenching.

CrN having corrosion resistance to an aqueous solution of sodium nitrate (electrolyte) or the like on the surface of the base material 12
A conductive ceramic coating layer 14 having a thickness of 3 to 5 μm is formed by a plasma CVD method, and has abrasion resistance and corrosion resistance to sodium nitrate, a hardness of Hv 1500 or more, and a specific electric resistance. Is 5 ×
An electrically insulating ceramic coating layer 16 made of Al ₂ O ₃ and having a thickness of 5 to 10 μm, which is 10 ¹⁴ Ω · cm or more, is laminated by a plasma CVD method. When the conductive ceramic coating layer 14 and the electrically insulating ceramic coating layer 16 are provided by such means, the temperature of the base material 12 can be about 500 ° C., but the alloy steel forming the base material 12 is 500 ° C. When the material is heated to a certain extent, the secondary hardening prevents the decrease in hardness.

The top surface of the herringbone ridge 10 is formed as a tool electrode portion 18 by polishing and removing the electrically insulating ceramic coating layer 16 to expose a part of the electrically conductive ceramic coating layer 14 on the surface. ing. Therefore, a portion other than the top surface of the herringbone-shaped protrusion 10 that exposes the conductive ceramic coating layer 14 to form the tool electrode portion 18 in the tool portion A1, that is, the protrusion 1
The side surface of 0, the bottom surface of the groove-shaped portion between the protrusions 10, and the aligning portion A2 all constitute an insulating portion covered with the electrically insulating ceramic coating layer 16. That is, the tool electrode portion 18 is exposed in the insulating portion whose surface is covered with the electrically insulating ceramic coating layer 16. Note that the electrically insulating ceramic coating layer 16 is not removed by polishing to expose a part of the conductive ceramic coating layer 14 on the surface, but other than the top surface of the herringbone-shaped protrusion 10 that forms the tool electrode portion 18. Electrically insulating ceramic coating layer only on part 1
It is also possible to stack 6 to form the insulating portion.

FIG. 3 is a sectional view of an essential part of an electrolytic processing apparatus using the electrolytic processing tool A of FIG. 1, FIG. 4 is an enlarged explanatory view of an essential part of the centering mechanism B in FIG. 3, and FIG. Alignment part A
2 is an enlarged view of a main part of FIG. 2, and FIG. 6 is a sectional view taken along line VI-VI in FIG.

In this electrolytic processing apparatus, the tool portion A1 and the centering portion A2 of the electrolytic processing tool A are arranged so as to project upward through the vertical through holes 20a of the annular support 20 made of an electrically insulating material. A sleeve member 22 for a dynamic pressure bearing, which is a workpiece, is provided on the horizontal upper surface of the annular support 20.
(The workpiece does not necessarily have a cylindrical inner peripheral surface or a cylindrical outer peripheral surface.) Is placed on the lower end surface with its axis oriented in the vertical direction. The aligning portion A2 and the tool portion A1 of A are connected to the sleeve member 2
The pressing plate 24 in a state of being inserted inside the cylindrical inner peripheral surface of
Also, by lowering the movable unit 26 including the centering mechanism B to a predetermined position shown in FIG. 3, the lower surface of the pressing plate 24 presses the upper surface of the sleeve member 22 and the inner peripheral surface of the sleeve member 22 and electrolytic processing. Tool part A1 of tool A
Is aligned. The tool electrode portion 18 of the tool portion A1 faces the lower inner peripheral surface of the sleeve member 22.

The centering mechanism B comprises a centering pressing member B1, a sphere holding member B2 and a centering sphere B3. An axial groove portion B1a having a radially outward opening is provided at a lower end portion of the centering presser member B1 for each 120 ° center angle in a plan view, and the lower end portion of each axial groove portion B1a is in an open state. Centering presser member B
1, a sphere holding member B2 is fitted and fixed, and three electrically insulating centering spheres B3 made of ceramic and having the same diameter are arranged between the sphere holding member B2 and the centering pressing member B1. ing.

The spherical body holding member B2 has a central insertion hole B2a through which the centering portion A2 of the electrolytic processing tool A is inserted, and a plan view 120.
The three sphere holding holes B2b provided for each of the center angles (θ ₁ , θ ₂ , θ ₃ ) and the sphere holding holes B2b are provided so as to project.
It has a fitting projection B2c which is fitted and fixed from below in the axial groove B1a of the centering presser member B1. Each ball holding hole B
2b holds the centering sphere B3 in a state of being slightly movable in the radial direction.

The movable unit 26 is lowered to adjust the centering portion A2.
The centering sphere B3 is brought into contact with the outer peripheral surface of the centering portion A2 by inserting the centering hole B2a of the sphere holding member B2. When the movable unit 26 is sufficiently lowered, each of the aligning spheres B3 is pushed radially outward by the outer peripheral surface of the aligning portion A2 and abuts on the inner peripheral surface of the sleeve member 22 as well. Both the outer peripheral surface of the centering portion A2 and the inner peripheral surface of the sleeve member 22 are pressed by the pressure. As a result, FIG.
As shown in ( ₄ ), since the distances (R ₁ , R ₂ , R ₃ ) from the axial center position of the centering portion A2 to the centers of the respective centering spheres B3 are all equal, the axial center line of the sleeve member 22 and the centering line are aligned. Heart A
2 and the axial center line of the tool part A1 will coincide.

Therefore, the tool electrode portion 18 and the sleeve member 2
Since the distance from the inner peripheral surface of 2 is constant in the circumferential direction and the radial direction, the tool electrode portion 18 serves as a cathode and the sleeve member 22 serves as an anode, and an aqueous sodium nitrate solution (electrolyte solution) is placed between the two.
By performing the electrolytic processing while flowing, the dynamic pressure herringbone groove portion can be formed with high accuracy on the lower inner peripheral surface of the sleeve member 22 in the circumferential direction and the radial direction. It should be noted that the sleeve member 22 in the state shown in FIG.
Similarly, a herringbone groove for dynamic pressure can be formed on the inner peripheral surface of the upper part of the.

Since the centering portion A2 has an electrically insulating ceramic coating layer 16 having abrasion resistance and corrosion resistance and a hardness of Hv1500 or more on the surface, the centering sphere B3 is formed on the surface of the outer peripheral surface of the reduced diameter portion. It is possible to prevent the occurrence of scratches and wear due to the like, or corrosion due to the electrolytic solution. In addition, alignment section A
Since the base material 12 of No. 2 is a sufficiently hard steel having a hardness of Hv 700 or more, it is possible to prevent deformation due to the pressing force of the centering sphere B3 or the like. Therefore, even when the ceramic centering sphere B3 that is sufficiently hard and has good wear resistance and corrosion resistance to the electrolytic solution is used, it is possible to prevent the positioning error due to the centering as described above. Further, the conductive ceramic coating layer 14 has high adhesiveness with the base material 12, and also has high adhesiveness with the electrically insulating ceramic coating layer 16. Therefore, the life of the aligning portion A2 is increased.

On the other hand, the tool electrode portion 18 made of the conductive ceramic coating layer 14 in the tool portion A1 and the electrically insulating ceramic coating layer 16 laminated on the conductive ceramic coating layer 14 both have corrosion resistance to the electrolytic solution. Therefore, the tool part A1 has a long life.

FIG. 7 is a sectional view of the essential parts of an electrolytic machining apparatus using another example of the electrolytic machining tool according to the present invention.

The electrolytic machining tool L has a right circular truncated cone-shaped first centering portion L1 at the upper end, and the outer peripheral surface of the first centering portion L1 is continuously reduced in diameter in the axial direction. It constitutes the outer peripheral surface portion. A first tool portion L3 and a second tool portion L4 are provided below the first aligning portion L1, and a second truncated cone-shaped second aligning portion L2 is provided below the first tool portion L3. The outer peripheral surface constitutes a diameter-reduced outer peripheral surface portion that continuously decreases in diameter in the axial direction. The forms of the base material, the conductive ceramic coating layer, the electrically insulating ceramic coating layer, and the tool electrode portion of the electrolytic machining tool L are the same as those of the electrolytic machining tool A in FIG. 1.

On the horizontal upper surface of the annular support 40, the sleeve member 42 for the dynamic pressure bearing, which is the workpiece, is placed on the lower end surface with its axis oriented in the vertical direction. 3 in a state in which the first centering portion L1 and the second centering portion L2, and the first tool portion L3 and the second tooling portion L4 are inserted inside the cylindrical inner peripheral surface of the sleeve member 42. An upper aligning mechanism M1 and a lower aligning mechanism M2 similar to the mechanism B
Are sufficiently inserted between the first centering portion L1 and the second centering portion L2 and the cylindrical inner peripheral surface of the sleeve member 42, respectively, so that the centering spheres M3 in the respective centering mechanisms M respectively have the first centering portion L1. Both the outer peripheral surfaces of the centering portion L1 and the second centering portion L2 and the inner peripheral surface of the sleeve member 42 are pressed, and the inner peripheral surface of the sleeve member 42 and the first tool portion L of the electrolytic processing tool L are pressed.
3 and the second tool part L4 are aligned. The tool portion in this case is not limited to two places as shown in FIG. 7, and may be one place.

FIG. 8 is a sectional view of the essential parts of an electrolytic processing apparatus using still another example of the embodiment of the electrolytic processing tool of the present invention.

In this case, the work piece is the shaft body 50 for the dynamic pressure bearing which is held upright. The electrolytic processing tool S has a cylindrical shape that is fitted onto the shaft body 50 with a radial gap, and the lower portion thereof is the tool portion S1 and the upper portion thereof is the aligning portion S2. The centering portion S2 includes a right circular truncated cone-shaped inner peripheral surface portion, that is, a diameter-reduced inner peripheral surface portion that has continuous rotational symmetry around the axis and that continuously contracts downward in the axial direction. Contrary to the example of FIG. 1, the tool portion S1 is provided with a herringbone-shaped ridge having a rectangular cross-section on the inner peripheral surface of the cylindrical surface over the entire circumference in the circumferential direction. The form of the base material, the conductive ceramic coating layer, the electrically insulating ceramic coating layer, and the tool electrode portion of the electrolytic processing tool S is shown in FIG.
It is the same as that of the electrolytic processing tool A.

In the above state, the aligning mechanism T similar to that shown in FIG. 3 is sufficiently inserted between the aligning portion S2 and the outer peripheral surface of the shaft body 50, so that the aligning sphere T1 is aligned with the aligning portion S2. Both the inner peripheral surface of the shaft body 50 and the outer peripheral surface of the shaft body 50 are pressed, and the outer peripheral surface of the shaft body 50 and the tool portion S1 of the electrolytic processing tool S are aligned.

The vertical positional relationship in the above description of the embodiments is merely for the convenience of description based on the drawings, and does not limit the actual use state or the like, and does not limit the components. The dimensions, the number, the material, the shape, and the relative arrangement thereof are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.

In addition, the description including the examples and the numerical ranges described for the present invention in the section of the means for solving the problems is applied to the above description of the embodiments in principle.

[0071]

According to the electrolytic machining tool of claims 1 to 10, since the base material of the centering portion is sufficiently hard and has the electrically insulating ceramic coating layer on the surface, the diameter-reduced outer peripheral surface portion or the diameter-reduced inner peripheral surface portion is formed. The surface is prevented from being scratched or worn by the centering sphere, etc., or from being corroded by the electrolytic solution, and is prevented from being deformed by the pressing force of the centering sphere, etc. It prevents the madness from occurring. Moreover, since the ceramic coating and the base material have high adhesion, the electrically insulating ceramic coating layer has excellent durability. Further, both the tool electrode part of which the surface is covered with the conductive ceramic coating layer and the insulating part of which the surface is covered with the electrically insulating ceramic coating layer in the tool part have corrosion resistance to the electrolytic solution. In this way, both the aligning portion and the tool portion have a long life, so that the life of the electrolytic processing tool as a whole is extended. In addition, since the tool electrode portion is protected by the conductive ceramic coating layer when it is used for industrial mass production of the dynamic pressure bearing by forming the dynamic pressure groove portion,
It is possible to prevent the processing accuracy of the dynamic pressure groove and the like from being lowered.

According to the eleventh to sixteenth aspects of the electrolytic machining tool, the tool electrode portion in which the surface of the tool portion is coated with the conductive ceramic coating layer and the insulating portion in which the surface is coated with the electrically insulating ceramic coating layer are both Also has corrosion resistance to the electrolytic solution. Therefore, the life of the electrolytic processing tool as a whole is extended.

In the electrolytic machining tool of claim 17, since the base material of the centering portion is sufficiently hard and has the electrically insulating ceramic coating layer on the surface, the centering on the surface of the diameter-reduced outer peripheral surface portion or the diameter-reduced inner peripheral surface portion is performed. It is possible to prevent scratches and abrasions due to the ball for use in the ball, corrosion due to the electrolytic solution, etc., and to prevent deformation due to the pressing force of the ball for the center, etc. Can be prevented. Moreover, since the ceramic coating and the base material have high adhesion, the electrically insulating ceramic coating layer has excellent durability. Therefore, the life of the electrolytic processing tool as a whole is extended.

[Brief description of drawings]

FIG. 1 is a schematic front view of an electrolytic processing tool.

FIG. 2 is an enlarged schematic sectional view of a tool portion in FIG.

3 is a cross-sectional view of a main part of an electrolytic processing apparatus using the electrolytic processing tool of FIG.

FIG. 4 is an enlarged explanatory view of a main part of the centering mechanism in FIG.

FIG. 5 is an enlarged view of a main part of an aligning portion in FIG.

6 is a sectional view taken along line VI-VI in FIG.

FIG. 7 is a cross-sectional view of essential parts of an electrolytic processing apparatus using another example of the electrolytic processing tool.

FIG. 8 is a cross-sectional view of main parts of an electrolytic processing apparatus using still another example of the electrolytic processing tool.

[Explanation of symbols]

10 ridges 10a top surface 12 Base material 14 Conductive ceramic coating layer 16 Electrically insulating ceramic coating layer 18 Tool electrode part 20 annular support 20a Vertical through hole 22 Sleeve member 24 Pressing plate 26 movable units 40 annular support 42 Sleeve member 50 axis A electrolytic processing tool A1 Tool Department A2 alignment section B alignment mechanism B1 Centering presser member B1a Axial groove B2 sphere holding member B2a central insertion hole B2b Sphere holding hole B2c Mating protrusion B3 Alignment sphere L electrolytic processing tool L1 alignment section L2 alignment section L3 tool section L4 tool section M1 upper alignment mechanism M2 sub-centering mechanism M3 alignment sphere S Electro-chemical processing tool S1 tool section S2 alignment section T alignment mechanism T1 alignment sphere h height

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ identification code FI theme code (reference) C25F 7/00 C25F 7/00 W

Claims (18)

[Claims] 1. An aligning portion having a diameter-reduced outer peripheral surface portion or a diameter-reduced inner peripheral surface portion which has a continuous rotational symmetry around a constant axis and continuously reduces in diameter toward one of the axial directions.
An electrolytic machining tool, which is located on an extension of the axis and has a tool portion exposing a tool electrode portion on the surface, wherein the aligning portion has at least a quenching treatment having a hardness of Hv 700 or more. A steel base material, which has an electrically insulating ceramic coating layer having wear resistance and corrosion resistance and a hardness of Hv 1500 or more on the surface, and the tool portion has an electrically insulating property having corrosion resistance. The tool electrode portion is exposed in an insulating portion whose surface is coated with a ceramic coating layer, and the tool electrode portion is formed by coating the surface with a conductive ceramic coating layer having corrosion resistance. Electrochemical machining tool characterized by the following. 2. The tool part has a conductive ceramic coating layer having corrosion resistance on a surface of a base material, and the tool electrode part is a part of the conductive ceramic coating layer in the tool part. Is exposed on the surface, and the insulating portion is formed by laminating an electrically insulating ceramic coating layer having corrosion resistance on the remaining portion of the conductive ceramic coating layer in the tool portion. The electrolytic processing tool according to 1. 3. The hardness of the base material of the aligning portion and the tool portion is Hv7.
It is an integral body made of at least quenching-treated steel of 00 or more, having a conductive ceramic coating layer having corrosion resistance on the surface part of the base material in the aligning part and the tool part, and the tool electrode part, A part of the conductive ceramic coating layer in the tool portion is exposed on the surface, and the hardness of the conductive ceramic coating layer in the aligning portion with abrasion resistance and corrosion resistance is Hv 1500 or more. Of the electrically insulative ceramic coating layers are laminated to form the surface of the aligning portion, and the hardness of the tool portion has abrasion resistance and corrosion resistance on the rest of the conductive ceramic coating layer. Is Hv15
The electrolytic machining tool according to claim 1, wherein at least 00 electrically insulating ceramic coating layers are laminated to form the insulating portion. 4. The steel comprises 0.3 to 2.5% by weight of C,
3.0 to 20.0% by weight of Cr, 0.5 to 1.5% by weight of Mo, and 0.1 to 0.5% by weight of V, or both, with the balance being iron and inevitable impurities. The electrolytic machining tool according to claim 1, wherein P and S that can be contained as impurities are 0.03% by weight or less, respectively. 5. A portion or all of 0.5 to 1.5% by weight of Mo in the alloy steel is replaced by W in an amount twice as much as that of Mo, and (Mo + 0.5W) is contained in the alloy steel. The electrolytic processing tool according to claim 4, wherein the rate is 0.5 to 1.5% by weight. 6. The alloy steel further comprises 0.05 to 0.5.
Wt% Si, 0.1 to 0.6 wt% Mn, 0.1
To 2.0 wt% Cu, and 0.1 to 2.0 wt%
The electrolytic processing tool according to claim 4 or 5, which contains one or two or more of Ni. 7. The electrolytic processing tool according to claim 1, wherein the specific electrical resistance of the electrically insulating ceramic coating layer is 5 × 10 ¹⁴ Ω · cm or more. 8. An electrically insulating ceramic coating layer,
The electrolytic processing tool according to any one of claims 1 to 7, which is made of Al ₂ O ₃ , Si ₃ N ₄ , or a diamond-like carbon thin film. 9. The electrolytic machining tool according to claim 1, wherein the conductive ceramic coating layer is made of a transition metal carbide, a transition metal nitride or a transition metal carbonitride. 10. The conductive ceramic coating layer comprises T
1 of iN, TiAlN, TiCN, NbN, and CrN
Alternatively, the electrolytic processing tool according to any one of claims 1 to 8, which comprises two or more. 11. An electrolytic machining tool having a tool part exposing a tool electrode part on the surface, wherein the tool part is an insulating part whose surface is covered with an electrically insulating ceramic coating layer having corrosion resistance. An electrolytic machining tool, wherein the tool electrode portion is exposed therein, and the tool electrode portion has a surface coated with a conductive ceramic coating layer having corrosion resistance. 12. The tool part has a conductive ceramic coating layer having corrosion resistance on a surface of a base material, and the tool electrode part is a part of the conductive ceramic coating layer in the tool part. Is exposed on the surface, and the insulating portion is formed by laminating an electrically insulating ceramic coating layer having corrosion resistance on the remaining portion of the conductive ceramic coating layer in the tool portion. 11. The electrolytic processing tool according to 11. 13. The specific electrical resistance of the electrically insulating ceramic coating layer is 5 × 10 ¹⁴ Ω · cm or more.
The electrolytic processing tool according to 1 or 12. 14. The electrolytic machining tool according to claim 11, 12 or 13, wherein the electrically insulating ceramic coating layer is made of Al ₂ O ₃ , Si ₃ N ₄ , or a diamond-like carbon thin film. 15. The electrolytic machining tool according to claim 11, wherein the conductive ceramic coating layer is made of a transition metal carbide, a transition metal nitride or a transition metal carbonitride. 16. The conductive ceramic coating layer comprises T
1 of iN, TiAlN, TiCN, NbN, and CrN
Alternatively, the electrolytic processing tool according to any one of claims 11 to 14, which comprises two or more. 17. An aligning portion having a diameter-reduced outer peripheral surface portion or a diameter-reduced inner peripheral surface portion which has a continuous rotational symmetry around a constant axis and continuously reduces in diameter toward one of the axial directions. An electrolytic machining tool, which is located on an extension of the axis and has a tool portion exposing a tool electrode portion on the surface, wherein the aligning portion has at least a quenching treatment having a hardness of Hv 700 or more. An electrolytic machining tool comprising steel as a base material and having an electrically insulating ceramic coating layer of Hv 1500 or more having wear resistance and corrosion resistance on the surface. 18. Between the sleeve body and the shaft body in the radial dynamic pressure bearing, with respect to the inner peripheral surface of the sleeve body or the outer peripheral surface of the shaft body of the sleeve body and the shaft body for constituting the radial dynamic pressure bearing. The electrolytic processing tool according to any one of claims 1 to 17, which is used to form a dynamic pressure groove portion for increasing a dynamic pressure of a lubricating fluid interposed in the groove.