JP2003254332A - Method and device for manufacturing dynamic pressure bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and easily form a dynamic pressure generating groove. <P>SOLUTION: This manufacturing device 1 is provided with a support 2 for supporting a dynamic pressure bearing 20 and a rod-like electrode 3 to be inserted into a shaft insertion hole 21 of the dynamic pressure bearing 20. In the rod-like electrode 3, an electrode part 31 is extended from a tip of a base part 33, and a projection part 32 is projected from the periphery thereof, and when the rod-like electrode 3 is inserted into the shaft insertion hole 21 of the dynamic pressure bearing 20, the projection part 3 separates between the projection part 3 itself and the inner peripheral surface of the shaft insertion hole 21 at the predetermined space. In the condition that a space between the shaft insertion hole 21 and the projection part 3 is filled with electrolyte, when a power source is turned on, an electrochemical reaction is generated to form the dynamic pressure generating groove 22 in the inner peripheral surface of the shaft insertion hole 21. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal bearing, for example, a dynamic pressure bearing which is an oil-impregnated bearing in which lubricating oil is impregnated in a porous material.

[0002]

2. Description of the Related Art An oil-impregnated bearing is a porous material impregnated with lubricating oil, and the lubricating oil contained in the pores of the oil-impregnated bearing when the shaft rotates is used in the sliding portion between the shaft and the oil-impregnated bearing. It exudes and performs a lubricating action.

In this oil-impregnated bearing, in order to generate a dynamic pressure for supporting the shaft on the lubricating oil, a dynamic pressure generating groove for guiding the lubricating oil as the shaft rotates is formed on the inner peripheral surface of the bearing that rotatably supports the shaft. Various types of dynamic pressure bearings have been proposed. For example, Japanese Patent Laid-Open No. 10-141358 discloses that
The first inclined groove portion and the second inclined groove portion are symmetrically opposed to each other,
The first inclined groove portion and the second inclined groove portion are arranged in parallel in the circumferential direction to form a herringbone dynamic pressure generating groove, and at the confluence of the first inclined groove portion and the second inclined groove portion. There has been proposed a dynamic pressure bearing having an annular groove that circulates in the circumferential direction.

[0004]

By the way, in the above dynamic pressure bearing, the dynamic pressure generating groove provided on the inner peripheral surface of the dynamic pressure bearing is formed by cutting using an NC lathe. Since such a herringbone type dynamic pressure generating groove is formed by arranging a plurality of first and second inclined groove portions side by side in the circumferential direction in a row, a single cutting step is required. Since the dynamic pressure generating groove cannot be continuously formed and the first and second inclined groove portions are cut one by one, the groove processing is troublesome and time-consuming. That is, the above-mentioned JP-A-1
The dynamic pressure bearing proposed in 0-141358 is the first
After forming the inclined groove portion of No. 1 to the end, the rotary drive mechanism of the NC lathe is forcibly stopped to form an annular groove portion at the end of the first inclined groove portion, and thereafter, the second inclined portion is formed at the end of the first inclined groove portion. A second inclined groove portion is formed from the annular groove portion in the direction opposite to the first inclined groove portion so that the base ends of the groove portions are aligned (see paragraph numbers 0018 to 0020 in the specification). Therefore, in order to form an accurate herringbone type dynamic pressure generating groove, after cutting one first inclined groove portion, the base end of the second inclined groove portion is aligned with the end of the first inclined groove portion. Since it is necessary to cut the inclined groove portion of 2,
Also, it is necessary to repeat the complicated work of positioning the second inclined groove portion depending on the number of both inclined groove portions, which is troublesome and troublesome.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method of manufacturing a dynamic pressure bearing in which a dynamic pressure generation groove can be formed easily and easily. Another object of the present invention is to provide a dynamic pressure bearing manufacturing apparatus capable of accurately carrying out the above method.

[0006]

In order to achieve the above object, the present invention proposes the following means. The invention according to claim 1 is a method of manufacturing a dynamic pressure bearing having a dynamic pressure generation groove on an inner peripheral surface of a shaft insertion hole of a metal bearing, which comprises:
The outer surface of the rod-shaped electrode, which is formed with a projection for creating a dynamic pressure generating groove on the outer peripheral portion, is kept in an insulating state, and a gap is formed between the inner peripheral surface and the shaft insertion hole of the metal bearing. When the rod-shaped electrode is inserted at a distance, and when the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole are immersed in an electrolytic solution, when the power is turned on with the rod-shaped electrode as the cathode and the metal bearing as the anode, The dynamic pressure generating groove is formed on the inner peripheral surface of the shaft insertion hole by an electrochemical reaction.

According to the manufacturing method of the present invention, when the power is turned on, an electrochemical reaction occurs between the projection of the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole of the dynamic pressure bearing, and the shaft insertion hole The inner peripheral surface of the shaft is electrolytically removed in a shape corresponding to the shape of the protrusion, so that a dynamic pressure generating groove is formed in the inner peripheral surface of the shaft insertion hole. The dynamic pressure generating groove of is obtained.

According to a second aspect of the present invention, in the method of manufacturing a dynamic pressure bearing according to the first aspect, the electrolytic solution is a sodium nitrate aqueous solution.

According to the manufacturing method of the present invention, since the electrolytic solution is an aqueous solution of sodium nitrate, when the dynamic pressure bearing is made of iron and the rod-shaped electrode is made of copper, stainless steel or the like, The electrochemical reaction is well performed, and the dynamic pressure generating groove can be surely formed in the shaft insertion hole.

According to a third aspect of the invention, in the method of manufacturing a dynamic pressure bearing according to the first or second aspect, the electrolytic solution is caused to flow through a gap between the rod electrode and the inner peripheral surface of the metal bearing. It is characterized by being.

According to the manufacturing method of the present invention, since the electrochemical reaction is carried out while the electrolytic solution is flowing, the electrochemical reaction can always be kept in a good state.

According to a fourth aspect of the present invention, there is provided a manufacturing apparatus of a dynamic pressure bearing having a dynamic pressure generating groove on the inner peripheral surface of the shaft insertion hole of the metal bearing, the support body supporting the metal bearing and the outer circumference. A rod-shaped electrode having a protrusion for forming a dynamic pressure generating groove formed on its outer surface, and the outer surface excluding the protrusion is coated with an insulating film, and the rod-shaped electrode has a shaft insertion hole of a metal bearing with an inner peripheral surface thereof. When the power is turned on with the rod-shaped electrode as the cathode and the metal bearing as the anode, it is equipped with an electrolyte solution supply mechanism that immerses the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole with the electrolyte solution when inserted with a gap The dynamic pressure generating groove is formed on the inner peripheral surface of the shaft insertion hole by an electrochemical reaction.

According to the manufacturing apparatus of the present invention, when the power is turned on, an electrochemical reaction is generated, and the inner peripheral surface of the shaft insertion hole is electrolytically removed, so that the shaft insertion hole has a shape corresponding to the protrusion. Since the pressure generating groove is formed, the dynamic pressure generating groove can be formed easily and easily. Thereby, the above method can be performed accurately.

According to a fifth aspect of the invention, in the dynamic pressure bearing manufacturing apparatus according to the fourth aspect, the electrolytic solution supply mechanism applies an electrolytic solution between the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole of the metal bearing. It is characterized by having a circulation system for circulation.

According to the manufacturing apparatus of the present invention, the electrolytic solution supply mechanism has a circulation system for circulating the electrolytic solution, and the electrolytic solution is provided between the projection of the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole of the dynamic pressure bearing. Since it can be circulated, the electrochemical reaction can always be kept in a good state.

According to a sixth aspect of the present invention, in the dynamic pressure bearing manufacturing apparatus according to the fourth or fifth aspect, the support body cooperates with the rod-shaped electrode to block the metal bearing and the rod-shaped electrode from the outside air. It is characterized by being supported in a vibrant atmosphere.

According to the manufacturing apparatus of the present invention, since the dynamic pressure bearing is supported by the support in the atmosphere which is shielded from the outside air, the electrochemical reaction can be satisfactorily performed also by this.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are views showing a dynamic pressure bearing manufacturing apparatus according to an embodiment of the present invention, FIG. 1 is an overall view showing the dynamic pressure bearing manufacturing apparatus, and FIG. A sectional view corresponding to the line AA of FIG. 1 showing a state where the rod-shaped electrode is inserted into the pressure bearing, FIG. 3 is an explanatory diagram showing the rod-shaped electrode, and FIG. 4 is a perspective view showing the tip side of the rod-shaped electrode. 5 is a sectional view showing a dynamic pressure generating groove formed in the dynamic pressure bearing. As shown in FIG. 1, the manufacturing apparatus 1 according to this embodiment is provided with an inner peripheral surface of the shaft insertion hole 21 of the dynamic pressure bearing 20,
This is for forming a dynamic pressure generating groove 22 for supporting a shaft (not shown) by an electrochemical reaction. The dynamic pressure bearing 20 forms a cylindrical metal bearing by lubricating a sintered body, which is a porous material, with lubricating oil.
Details of the dynamic pressure bearing 20 are shown in FIG. And
The manufacturing apparatus 1 roughly includes a support 2 that supports the dynamic pressure bearing 20, and a rod-shaped electrode 3 that is inserted into the shaft insertion hole 21 of the dynamic pressure bearing 20.

The support body 2 is formed by projecting a peripheral edge portion 4 downward on the outer periphery of the bottom surface. When the dynamic pressure bearing 20 is fitted in the peripheral edge portion 4, the support body 2 cooperates with the rod-shaped electrode 3 to support the dynamic pressure bearing. It is designed to support 20. The rod-shaped electrode 3 is attached to an insertion mechanism (not shown) such as an air cylinder in a lower portion of the support body 2 and is provided so as to be able to move up and down, and the dynamic pressure bearing 20 is fitted into the peripheral edge portion 4 of the support body 2. When combined, the electrode portion 31 rises from below and is inserted into the shaft insertion hole 21 of the dynamic pressure bearing 20, so that the base 33 and the support body 2 form the dynamic pressure bearing 20.
To pinch. At that time, the shaft insertion hole 2 of the dynamic pressure bearing 20
As shown in FIG. 2, a protrusion 32 protruding from the electrode portion 31 is inserted into the inner peripheral surface of the electrode 1 so as to separate a desired gap.

The rod-shaped electrode 3 is, as shown in FIGS. 3 and 4,
The electrode portion 31 formed in the shape of, for example, a thin rectangular column is extended at the tip of the base portion 33, and the protrusion 32 is provided on the outer peripheral portion thereof. The protrusion 32 is for forming the dynamic pressure generating groove 22 of the dynamic pressure bearing 20, and is, for example, the electrode unit 3.
Each of the surfaces 1 has a dogleg shape, and as shown in FIG. 2, it is formed so as to bulge in an arc shape along the inner peripheral surface of the dynamic pressure bearing 20 as a whole. When the rod-shaped electrode 3 as described above is subjected to an electrochemical reaction, the outer surfaces of the electrode portion 31 and the base portion 33 are entirely coated with the insulating material 5 in advance as shown in FIG. By grinding the insulating material 5 from the surface, only the tips of the protrusions 32 are exposed as shown in FIG. 3B, and the tips of the protrusions 32 are used in an exposed state. That is, when the rod-shaped electrode 3 is inserted into the shaft insertion hole 21 of the dynamic pressure bearing 20, a predetermined gap is formed between the projection 32 of the electrode portion 31 and the inner peripheral surface of the shaft insertion hole 21. There is. The insulating material 5 is made of, for example, an epoxy resin, but may be any material that is not affected by the electrolytic solution described later.

Further, the manufacturing apparatus 1 is provided with an electrolytic solution supply mechanism 6 which, when the rod-shaped electrode 3 is inserted into the shaft insertion hole 21, makes a space between the both electrodes 3 and 21 immersed in the electrolytic solution. The electrolytic solution supply mechanism 6 has, for example, an electrolytic solution source 61 and a pump 62 that supplies the electrolytic solution in the electrolytic solution source 61 as shown in FIG. 1. The electrolytic solution from the pump 62 corresponds to the rod-shaped electrode 3. It is adapted to be supplied into the shaft insertion hole 21 via a supply channel 63 provided in the base portion 33.

In this case, the support 2 is provided with a return flow path 64 which communicates with the shaft insertion hole 21 of the dynamic pressure bearing 20, and the electrolytic solution supplied into the shaft insertion hole 21 is returned to the return flow path 64.
The electrolytic solution is circulated by being connected to the supply flow path 63 via the pipe 65. for that reason,
The electrolytic solution supply mechanism 6 has a circulation system including a return channel 64 and a pipe 65 for circulating the electrolytic solution. A filter 66 is provided at an intermediate position of the pipe 65.

Then, the shaft insertion hole 2 is formed by the electrolytic solution.
1 and the protrusion 32 are immersed, the rod-shaped electrode 3
Is connected to the cathode terminal 7 and the dynamic pressure bearing 20 is connected to the anode terminal 8 and the power is turned on, an electrochemical reaction occurs and a dynamic pressure generating groove 22 is formed on the inner peripheral surface of the shaft insertion hole 21.
Are formed.

Here, as the electrolytic solution, for example, when the dynamic pressure bearing 20 is made of iron (Fe) and the rod-shaped electrode 3 is made of copper (Cu) or stainless, an aqueous solution of sodium nitrate (about 20% of NaNO ₃ is used). Aqueous solution), and the electrochemical reaction is performed according to the following relationship. That is, pre-electrification) a) conductive away ^{_{NaNO 3 → Na + + NO 3}} - H 2 O → H + + OH - being energized) a) anodic reaction ^{Fe → Fe 2+ + 2e - Fe} 2+ + 2NO 3 - → Fe (NO 3 ) ₂ Fe (NO ₃ ) ₂ + 2NaOH → 2Na ⁺ + 2NO ₃ ⁻ + Fe (OH) ₂ Total reaction formula Fe + 2H ₂ O → Fe (OH) ₂ + H ₂ Further reacting with water and oxygen 4Fe (OH) ₂ + 2H ₂ O + O ₂ → 4Fe (OH) ₃ On the one hand, oxygen generation 2OH ⁻ → H ₂ O + 1 / 2O ₂ ↑ + 2e ⁻ b) Cathodic reaction 2Na ⁺ + 2H ₂ O + 2e ⁻ → 2NaOH + H ₂ ↑

That is, when electricity is applied between the dynamic pressure bearing 20 and the projection 32 of the rod-shaped electrode 3, an electrochemical reaction occurs due to an aqueous solution of sodium nitrate, so that the inner peripheral surface of the shaft insertion hole 21 of the dynamic pressure bearing 20 projects. Iron hydroxide (Fe (OH) ₂ ) is formed in a shape corresponding to the portion 32, and the iron hydroxide is electrolytically removed, so that the dynamic pressure generating groove 22 as shown in FIGS.
Are formed.

The power supply supplied to the dynamic pressure bearing 20 and the rod-shaped electrode 3 is a pulse power supply system, and the dynamic pressure generating groove 22 is formed by repeating the on time and the off time of the pulse. The processing time required for this can be obtained. Incidentally, in this embodiment, the peak current is 20 A, the pulse on time is 10 msec,
When the pulse-off time is set to 40 msec, a pulse power supply that can obtain the dynamic pressure generating groove 22 having a depth of about 0.06 to 0.10 mm in a processing time of 3 sec is adopted. The processing time is preselected based on the depth and width of the dynamic pressure generating groove 22 to be formed.

Since the manufacturing apparatus 1 of this embodiment is configured as described above, the method of the present invention will be described next in relation to its operation. First, by fitting the dynamic pressure bearing 20 in the peripheral edge portion 4 of the support body 2 and inserting the electrode portion 31 of the rod-shaped electrode 3 into the shaft insertion hole 21 of the dynamic pressure bearing 20, Together with the rod-shaped electrode 3, the dynamic pressure bearing 20 is supported in an atmosphere isolated from the outside air. At this time, the projection 32 of the electrode portion 31 and the inner peripheral surface of the shaft insertion hole 21 are separated from each other by a gap necessary for the electrochemical reaction as shown in FIGS. In this state, the electrolytic solution supply mechanism 6 supplies the electrolytic solution so that the projection 32 of the electrode portion 31 and the inner peripheral surface of the shaft insertion hole 2 are immersed in the electrolytic solution.

When the rod-shaped electrode 3 is connected to the cathode terminal 7 and the dynamic pressure bearing 20 is connected to the anode terminal 8 and the power supply is turned on in that connection state, the protrusion 32 of the rod-shaped electrode 3 and the dynamic pressure are connected. An electrochemical reaction occurs between the inner peripheral surface of the shaft insertion hole 21 of the bearing 20 and the inner peripheral surface of the shaft insertion hole 21 is electrolytically removed in a shape corresponding to the shape of the protrusion 32. A dogleg-shaped dynamic pressure generating groove 22 is formed on the inner peripheral surface of the shaft insertion hole 21, whereby a desired dynamic pressure generating groove 22 is obtained on the inner peripheral surface of the dynamic pressure bearing 20.

That is, according to the method of the present invention, the protrusion 32 corresponding to the shape to be formed is formed on the electrode portion 31 of the rod-shaped electrode 3, and the protrusion 32 is inserted into the shaft insertion hole 21 of the dynamic pressure bearing 20. Since the dynamic pressure generating groove 22 can be electrochemically formed by inserting the inside, the dynamic pressure generating groove 22 can be formed easily and easily, without the trouble and labor required of an NC lathe.

Further, since the rod-shaped electrode 3 is connected to the cathode terminal 7 and the dynamic pressure bearing 20 is connected to the anode terminal 8, respectively, as compared with the case where they are connected in a reverse polarity form such as electric discharge machining, electrolytic removal is performed. Bearing 2 whose slag is the work
There is no risk of sticking to the inner peripheral surface of 0. Moreover, since the electrolytic solution is an aqueous solution of sodium nitrate, when the dynamic pressure bearing 20 is made of iron and the rod-shaped electrode 3 is made of copper (or stainless steel), the electrochemical reaction is well performed, The dynamic pressure generating groove 22 can be reliably formed in the shaft insertion hole 21.

In the manufacturing apparatus 1 of this embodiment, only the support 2 for supporting the dynamic pressure bearing 20 and the protrusion 32 are exposed, and the inner peripheral surface of the shaft is inserted into the shaft insertion hole 21 of the dynamic pressure bearing 20. And a rod-shaped electrode 3 inserted with a gap therebetween, and an electrolytic solution supply mechanism 6 for immersing the rod-shaped electrode 3 and the shaft insertion hole 21 in an electrolytic solution. The rod-shaped electrode 3 is connected to the cathode terminal 7 and , The dynamic pressure bearing 20 is connected to the anode terminal 8 to cause an electrochemical reaction, and the shaft insertion hole 2
Since the inner peripheral surface of No. 1 is electrolytically removed, the dynamic pressure generation groove 22 having a shape corresponding to the protrusion 32 is formed in the shaft insertion hole 21, so that the dynamic pressure generation groove 22 is easily and easily formed. The above method can be performed accurately.

Moreover, the electrolytic solution supply mechanism 4 includes the return passage 6
4 and the pipe 65 have a circulation system for circulating the electrolytic solution, so that the protrusion 32 of the rod-shaped electrode 3 and the dynamic pressure bearing 20 are provided.
The electrolytic solution can be circulated between the inner peripheral surfaces of the shaft insertion holes 21 and the electrochemical reaction can be always maintained in a good state.

Further, when the support body 2 supports the dynamic pressure bearing 20 together with the rod-shaped electrode 3, the lower part of the dynamic pressure bearing 20 is held by the rod-shaped electrode 3.
While the upper part is covered with the support 2, the dynamic pressure bearing 2
Since the space between 0 and the protrusion 32 of the rod-shaped electrode 3 is shielded from the outside air, an electrochemical reaction can be satisfactorily performed.

6 and 7 show the main parts of the second embodiment of this manufacturing apparatus. In this case, as shown in FIG. 6, the electrode portion 31 of the rod-shaped electrode 3 is formed in a columnar shape, and the spirally-shaped first protrusion 32 a that is wound in the right direction is provided around the columnar electrode portion 31. , A spiral second protrusion 32b which is reversely wound is provided, and further,
The end of the first protrusion 32a and the tip of the second protrusion 32b are connected by the connecting protrusion 32c, and the end of the second protrusion 32b and the tip of the first protrusion 32a are also connected by the connecting protrusion 32d. There is.

The rod-shaped electrode 3 having the first protrusion 32a, the second protrusion 32b, and the connecting protrusions 32c and 32d for connecting them to each other is inserted into the shaft insertion hole 21 of the dynamic pressure bearing 20. Then, when the power is turned on, the inner peripheral surface of the shaft insertion hole 21 is electrolytically removed in a shape corresponding to each of the protrusions 32a to 32d. As a result, the rear side of the shaft insertion hole 21 is as shown in FIG. Is formed with a first groove portion 22a and a second groove portion 22b that intersect each other in an inclined state,
Further, as shown in FIG. 2B, a first groove portion 22a and a second groove portion 22b which intersect each other in a tilted state are formed on the front side of the shaft insertion hole 21, and the connecting protrusions 32c, 3 are formed.
The first and second connection grooves 22c and 22d corresponding to 2d are formed.

That is, the shaft insertion hole 2 of the dynamic pressure bearing 20.
In 1, the spiral first protrusion 32a and the second protrusion 32b that are inclined in opposite directions can be collectively formed. Therefore, when forming with the NC lathe, the first groove 22a is formed. After that, not only the troublesome positioning work of forming the second groove portions 22b in alignment with the end portions thereof becomes unnecessary, but also the additional formation of the second groove portions 22b becomes unnecessary, and the dynamic pressure generating groove 22 is formed. It can be formed very easily.

Therefore, according to the method and manufacturing apparatus 1 of the present invention, the dynamic pressure generating groove 2 provided in the dynamic pressure bearing 20 is changed by changing the shape of the rod-shaped electrode 3 inserted in the dynamic pressure bearing 20.
2 can be formed in any shape, and the dynamic pressure generating groove 22
It is also possible to make it into a shape that can maximize its function.

By the way, when the dynamic pressure bearing 20 is used, the lubricating oil contained in the dynamic pressure bearing 20 oozes out as the shaft 9 supported on the inner peripheral surface thereof rotates, so that the dynamic oil bearing 20 is provided between the inner peripheral surface and the outer peripheral surface of the shaft 9. An oil film is formed. The lubricating oil that has exuded is attached to the rotating shaft 9 and forms the dynamic pressure generating groove 22.
It flows in the rotation direction of the shaft 9 along the 2a and the second groove portion 22b. At this time, the first groove portion 22a and the second groove portion 22b
Circulates in an annular shape, and therefore circulates between the groove portions 22a and 22b. Then, at the intersection of the first and second groove portions 22a and 22b, as shown by an arrow B in FIG. 7 (a), the lubricating oil is squeezed, and both the first and second groove portions 22a and 22b reach the intersection portion. Due to the applied pressing force, a dynamic pressure, that is, a hydraulic pressure is generated in a direction of supporting the shaft 9, so that the shaft 9 is supported in a non-contact state with the dynamic pressure bearing 20. In this case, since the first groove portion 22a and the second groove portion 22b are both inclined at the same angle θ, the pressing force is evenly applied from both the first groove portion 22a and the second groove portion 22b at the intersection. The shaft 9 can be stably supported.

In this embodiment, an example in which the rod-shaped electrode 3 is inserted into the dynamic pressure bearing 20 by raising it from below with respect to the support body 2 is shown, but the present invention is not limited to this, and it can be lowered from above. However, it is not limited to the illustrated example.

[0040]

As described above, according to the invention of claim 1, an electrochemical reaction is generated between the protrusion of the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole of the dynamic pressure bearing, and the shaft is generated. Since the inner peripheral surface of the insertion hole is electrolytically removed to form the desired dynamic pressure generating groove on the inner peripheral surface of the shaft of the dynamic pressure bearing, the dynamic pressure generating groove can be formed easily and easily. The effect that can be obtained is obtained.

According to the second aspect of the present invention, since the electrolytic solution is an aqueous solution of sodium nitrate, it is possible to reliably form the dynamic pressure generating groove in the shaft insertion hole. According to the invention of claim 3, since the electrochemical reaction is carried out while the electrolytic solution is flowing, the electrochemical reaction can always be kept in a good state.

According to the invention of claim 4, since the dynamic pressure generating groove having a shape corresponding to the projection is formed in the shaft insertion hole, the dynamic pressure generating groove can be formed easily and easily. The effect that the above method can be performed accurately can be obtained.

According to the invention of claim 5, the electrolytic solution can be circulated between the projection of the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole of the dynamic pressure bearing by the circulation system of the electrolytic solution supply mechanism. The effect that the electrochemical reaction can always be kept in a good state is obtained.

According to the invention of claim 6, since the dynamic pressure bearing is supported by the support in the atmosphere which is shielded from the outside air, the effect that the electrochemical reaction can be favorably carried out can also be obtained. .

[Brief description of drawings]

FIG. 1 is a diagram showing a dynamic pressure bearing manufacturing apparatus according to an embodiment of the present invention, which is an overall view showing the dynamic pressure bearing manufacturing apparatus.

FIG. 2 is a sectional view corresponding to line AA of FIG. 1, showing a state in which a rod-shaped electrode is inserted into the dynamic pressure bearing of the manufacturing apparatus.

3A and 3B are views showing a rod-shaped electrode, wherein FIG. 3A is a cross-sectional view showing a state where the projection of the rod-shaped electrode is coated with an insulating film, and FIG. 3B is a cross-sectional view showing a state where the projection of the rod-shaped electrode is exposed. Is.

FIG. 4 is a perspective view showing a tip side of a rod-shaped electrode.

FIG. 5 is a cross-sectional view showing a dynamic pressure generation groove formed in a dynamic pressure bearing.

FIG. 6 is a rear view of a rod-shaped electrode showing a main part of a dynamic pressure bearing manufacturing apparatus according to a second embodiment of the present invention.

7A and 7B are views showing a dynamic pressure generating groove formed in the dynamic pressure bearing, wherein FIG. 7A is a sectional view of the shaft insertion hole of the dynamic pressure bearing as seen from the rear side, and FIG. It is sectional drawing which looked at the shaft insertion hole from the front part side.

[Explanation of symbols]

1 Manufacturing equipment 2 support 3 Rod electrodes 31 Electrode part 32 Projection 32a first protrusion 32b Second protrusion 32c, 32d connection protrusion 4 peripheral part 5 insulation 6 Electrolyte supply mechanism 61 Electrolyte source 62 pumps 63 supply channel 64,65 Circulatory system 66 filters 7 Cathode terminal 8 Anode terminal 9 shaft 20 Dynamic bearing 21 Shaft insertion hole 22 Dynamic pressure generation groove 22a first groove 22b Second groove part 22c, 22d Connection groove part 32a first protrusion 32b Second protrusion 32c, 32d First and second connecting protrusions

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katsuyuki Uehara             3158-1 Nagaike, Okaya-shi, Nagano Katsu Co., Ltd.             Within the hawk (72) Inventor Ikuo Horiuchi             795-6 Uedahara, Ueda City, Nagano Stock Association             Company Green Seiko F term (reference) 3C059 AA02 AB01 DA03 EA02 HA17                 3J011 BA02 CA02 DA02

Claims (6)

[Claims] 1. A method of manufacturing a dynamic pressure bearing having a dynamic pressure generation groove on the inner peripheral surface of a shaft insertion hole of a metal bearing, wherein a protrusion for forming the dynamic pressure generation groove is formed on the outer peripheral portion of the rod electrode in advance. The outer surface excluding the protrusion is formed into an insulating state, and the rod-shaped electrode is inserted into the shaft insertion hole of the metal bearing with a gap from the inner peripheral surface thereof, and the rod-shaped electrode and the shaft are inserted. The shaft insertion hole is formed by an electrochemical reaction between the protrusion and the metal bearing with the rod-shaped electrode as the cathode and the metal bearing as the anode, with the inner surface of the hole immersed in the electrolyte. A method for manufacturing a dynamic pressure bearing, wherein the dynamic pressure generating groove is formed on the inner peripheral surface of the. 2. The method of manufacturing a dynamic pressure bearing according to claim 1, wherein the electrolytic solution is an aqueous solution of sodium nitrate. 3. The method for manufacturing a dynamic pressure bearing according to claim 1, wherein the electrolytic solution is circulated through a gap between the rod-shaped electrode and the inner peripheral surface of the metal bearing. Method for manufacturing dynamic pressure bearing. 4. A device for manufacturing a dynamic pressure bearing having a dynamic pressure generation groove on an inner peripheral surface of a shaft insertion hole of a metal bearing, wherein the support body supports the metal bearing and a dynamic pressure generation is generated at an outer peripheral portion. A rod-shaped electrode in which a protrusion for forming a groove is formed and the outer surface excluding the protrusion is in an insulating state, and the rod-shaped electrode is provided in a shaft insertion hole of a metal bearing with a gap from the inner peripheral surface thereof. Equipped with an electrolyte solution supply mechanism that immerses the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole in the electrolyte solution when inserted, and the power source is connected with the rod-shaped electrode as the cathode and the metal bearing as the anode. An apparatus for manufacturing a dynamic pressure bearing, which is characterized in that 5. The dynamic pressure bearing manufacturing apparatus according to claim 4, wherein the electrolytic solution supply mechanism circulates the electrolytic solution through a gap between the rod-shaped electrode and the inner peripheral surface of the shaft insertion hole of the metal bearing. An apparatus for manufacturing a dynamic pressure bearing, comprising: 6. The dynamic pressure bearing manufacturing apparatus according to claim 4, wherein the rod-shaped electrode is in contact with the end surface of the metal bearing when inserted into the shaft insertion hole of the metal bearing. Is formed, the support body sandwiches a metal bearing from both ends with the step portion of the rod-shaped electrode, and both ends of the gap are closed between the support body and the step portion of the rod-shaped electrode. The manufacturing apparatus for a dynamic pressure bearing is characterized in that the gap in the closed state is lightly oiled and the electrolytic solution is supplied from one of the support and the step of the rod-shaped electrode toward the other.