JPH0911114A - Surface finish process method - Google Patents

Abstract

PURPOSE: To provide a surface finish process method effective in the removal of loading in a thin hole in a precision workpiece and others. CONSTITUTION: A thin through hole 12 portion formed in a ceramic cap 11 is immersed in HR fluid 14. Electrodes 14, 15 are disposed respectively above and below the ER fluid 13 and an electric field is applied to the electrodes, while vibrations are giving between the ER fluid 13 and ceramic cap 11 by a vibrator 18. Fine granular clusters in the ER fluid 13 are formed in the thin through hole 12 of the ceramic cap 11 in parallel to the thin through hole 12 and the clusters act as a lapping rod to carry out the finish process for the inner surface of the thin through hole 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface finishing method applied to the removal of clogging in holes of various machined parts, deburring, finish polishing, precision rounding and the like.

[0002]

2. Description of the Related Art Generally, mechanical polishing using a fine grain abrasive is used for finish polishing of various machined parts. However, depending on the part, the shape and position of the surface to be polished may
It is impossible or extremely difficult to apply mechanical pressure. A magnetic polishing method that uses a magnetic abrasive to generate a polishing pressure by the action of a magnetic field is known as an effective polishing method for the surface finish of a curved surface or an inner surface of a cylinder, but there are precision parts that are difficult to apply even with this method. .

One such component is, for example, the ceramic cap 94 of the limiting current type ceramic oxygen sensor 90 shown in FIG. This ceramic oxygen sensor 90
Is composed of a ceramic ion conductor 91 having pumping electrodes 92 and 93 formed on both surfaces thereof, and a ceramic cap 94 having through pores 95 provided on one surface thereof. A heater 96 is provided on the ceramic cap 94.
Are formed. The through-pores 95 opened in the ceramic cap 94 are for supplying oxygen to the ceramic ion conductor 91 by diffusion rate control, whereby so-called limiting current characteristics are obtained.

In the small-sized limiting current type ceramic oxygen sensor, the through pore 95 has a diameter of 10 μm or less and a depth of about 0.8 mm. When the ceramic cap 94 in which such through-holes 95 are formed in advance is mechanically polished, the through-holes 95 are clogged with abrasive grains. Since the diameter of the through pores 95 is small and deep, even if ultrasonic cleaning is performed thereafter, about 30% of the polishing abrasive grains remain without being removed and do not function sufficiently as diffusion-controlled pores, resulting in a defective product.

Further, as shown in FIG. 10, when a hole 101 is formed in a side surface of a metal or plastic pipe 100, a burr 102 is formed on the inner surface of the pipe. If the pipe 100 is extremely small, it is difficult to finish polish the burr 102 on the inner surface of the pipe 100.

[0006]

As described above, in many precision machined parts, it is difficult to finish the surface in terms of shape, size, position and the like. The present invention has been made in view of the above points, and an object of the present invention is to provide a surface finishing treatment method useful for removing clogging in holes of machined parts, deburring, finish polishing, precision rounding, and the like.

[0007]

According to the surface finishing method of the present invention, first, at least the surface of a machined part to be finished is immersed in an electrorheological fluid in which dielectric fine particles are dispersed in an insulating solvent. And an electric field is applied to the electrorheological fluid to apply a vibration that causes a frictional force between the electrorheological fluid and the surface of the machined part to be finished.

The surface finishing method according to the present invention is a second method.
, At least the surface of the machined part to be finished,
The surface of the electrorheological fluid and the machined part to be finished by immersing it in an electrorheological fluid in which dielectric particles and ferromagnetic particles are dispersed in an insulating solvent and applying an electric field and a magnetic field to the electrorheological fluid. It is characterized by giving a vibration that causes a frictional force between and.

In the present invention, preferably, the electric field applied to the electrorheological fluid is in a direction parallel to the surface of the workpiece to be finished. Further, the vibration that causes a frictional force between the electrorheological body and the machined component may mechanically vibrate the machined component from the outside, or may mechanically vibrate the electrode for applying an electric field to the electrorheological fluid from the outside. You can do it. Alternatively, instead of such mechanical vibration, a method of vibrating the dielectric fine particles in the electro-viscous body only by an electric force by using an electric field applied to the electro-viscous body as an alternating electric field of relatively low frequency may be used.

[0010]

[Operation] Electro-Rheorogical Fluid,
The ER fluid) is a kind of colloidal solution in which dielectric particles are uniformly dispersed in an insulating solvent. When an electric field is applied, the dispersed particles cause dielectric polarization to form clusters, and an apparent viscosity. Is known to change. The ER fluid has been attempted to be applied to, for example, a vehicle shock absorber, a clutch, an engine mount, etc. by utilizing its viscosity change.

The present invention utilizes, as a polishing agent, clusters in which dispersed fine particles are linked in a chain, which causes viscosity increase (so-called ER effect) when an electric field is applied to an ER fluid. That is, when an electric field is applied to the ER fluid to form clusters, and relative vibration is applied between the ER fluid and the surface of the machined part to be finished, which causes frictional force, surface treatment becomes possible. Become.

In particular, when the direction of the electric field applied to the ER fluid and the direction of relative vibration are set parallel to the surface to be finished, it is possible to remove clogging in the through pores and finish polishing the inner surface of the micropipe, which were difficult in the past. You can easily. That is, when the directions of the electric field and the vibration are set as described above, a large number of clusters connected in a chain form are formed in the ER fluid in parallel with the surface to be processed, and this acts as a so-called minute lapping rod.

The same surface finishing treatment can be performed by using an ER fluid in which dielectric fine particles and ferromagnetic fine particles are dispersed in an insulating solvent. In this case, by applying an electric field and a magnetic field to the ER fluid, it is possible to exert the frictional force of the dielectric fine particles and the frictional force of the ferromagnetic fine particles. Therefore, by selecting these fine particle materials, effective surface finishing treatment becomes possible. In particular, the combination of electric and magnetic fields provides a wide variety of processing conditions.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an apparatus configuration of an embodiment applied to remove clogging inside a through hole of a ceramic cap 11 used in the above-described limiting current type ceramic oxygen sensor. As described above, the ceramic cap 11 is mechanically polished in the state in which the fine through holes 12 are formed in advance, and the through holes 12 are clogged with an abrasive that cannot be mechanically taken out. One end of this ceramic cap 11 is fixed by a supporting member 19.

Through-pore 12 of ceramic cap 11
Are kept immersed in the ER fluid 13. Specifically, for example, the ER fluid 13 is dropped from above the cap 11,
By sucking this from below, the inside of the through hole 12 is completely ER
It is filled with the fluid 13. The ER fluid 13 has Cu electrodes 14 and 15 for applying an electric field above and below it.
Is arranged, and electric power is supplied from the power supply 16 to this. In the embodiment, an AC power supply of 20 to 50 Hz is used as the power supply 16.

The electrodes 14 and 15 are supported by a support member 17, and the support member 17 is vibrated by a vibration exciter 18 as indicated by an arrow in the figure. That is, in FIG. 1, the surface to be treated is the inner surface of the through hole 12 of the cap 11, and the ER fluid 13 has the through hole 1 thereof.
2 is applied, and the electrodes 14 and 15 are vibrated in parallel to the through pores 12, resulting in the ER fluid 13
Relative vibration is applied between the inner wall of the through hole 12 and the through hole 12.

The ER fluid 13 is, for example, an alkylnaphthalene or silicone oil used as an insulating solvent, in which beard-like crystals (whiskers) of calcium carbonate having high hardness are dispersed as dielectric fine particles. The whiskers have a length of 10 to 30 μm and a diameter of about 1 μm.

FIG. 2 shows how the particles of the ER fluid 13 are dispersed. When no electric field is applied between the electrodes 14 and 15, the whiskers 13b are uniformly dispersed in the solvent 13a in random directions, as shown in FIG. 2 (a). When an electric field is applied to this, as shown in FIG. 2B, at the same time as the individual whiskers 13b are dielectrically polarized,
These are connected to each other in a chain to form a cluster 13c. In particular, by applying an AC electric field of about 50 Hz, a high polarizability can be obtained, and individual whiskers become electric dipoles and are connected to each other to form the cluster 13c.

In the case of the embodiment shown in FIG. 1, the cluster 13c has the through holes 1 in the through holes 12 of the cap 11 as shown in the enlarged cross-sectional view of FIG.
Arrange in parallel with 2. Therefore, when the electrodes 14 and 15 are vertically vibrated, as shown in the plan view of FIG. 3B, the cluster 13c causes the minute lapping bar to be formed against the abrasive grains 20 attached to the inner wall of the through hole 12. Work as. That is, a frictional force is applied to the inner surface of the through-pore 12 and the abrasive grains 20
Will be scraped out. Actually, the applied voltage is 1-2
It was confirmed that the abrasive clogged in the through-pores 12 that could not be taken out by ultrasonic cleaning could be removed cleanly by setting the kV (frequency 20 to 50 Hz) and the applied vibration to a total amplitude of 0.175 mm (frequency 20 Hz).

The dielectric fine particles to be dispersed in the ER fluid are not limited to calcium carbonate whiskers, and other fine particles which are easily polarized and have a hardness higher than a certain degree and are suitable for polishing, such as barium titanate or silica, and insulating. A coated metal or the like can be used. The shape of the fine particles is not limited to whiskers, and may be spherical.

The actual surface finishing process of the ceramic cap 13 can be performed, for example, as shown in FIG. While transporting the mechanically polished cap 11 having the through pores 12 formed thereon by a transporting means such as a belt conveyor (not shown), the ER fluid 13 is dropped as shown in FIG. Fill 12 with ER fluid 13.
Next, as shown in (b), E and
An electric field is applied by contacting with the R fluid 13, and at the same time, relative vibration is applied between the electrodes 14 and 15 and the cap 11 in the same direction as the electric field. Finally, as shown in (c), the ER fluid 13
Is removed by washing.

Alternatively, batch processing as shown in FIG. 5 is also possible. As shown in the figure, the ER fluid 53 is put in the container 51, and a plurality of mechanically polished ceramic caps 11 are erected and held therein by the support tray 52. Tray 5
2 is vibrated in the arrow direction by a rod 54 that penetrates the container 51 in a liquid-tight manner. Further, parallel electrodes 55 and 56 are arranged in the ER fluid 53, and these are connected to an AC power source 57. Then, while applying the electric field to the ER fluid 53, the cap 11 is vibrated in parallel with the electric field,
Clean the inside of the through pores.

FIG. 6 shows another embodiment of the present invention, in which a small pipe 65 is machined to form a hole 66 and then the inner surface thereof is deburred. As shown in the figure, a container 63 containing an ER fluid 62 is provided with a rod 63 that can move forward and backward while maintaining liquid tightness. The pipe 65 to be finished is immersed in the ER fluid 62 while being supported by a support base 64 fixed to the rod 63. In the ER fluid 62,
Parallel electrodes 67 and 68 are arranged so as to sandwich the pipe 65, and a power source 69 is connected thereto.

Then, an electric field is applied to the ER fluid 62 in parallel with the longitudinal direction of the pipe 65, and at the same time, a reciprocating vibration parallel to the electric field is applied to the rod 63. As a result, the ER fluid 62
A cluster is formed in parallel with the pipe 65, and the vibration applied from the rod 63 to the pipe 65 causes a frictional force between the cluster and the inner surface of the pipe 65 to enable deburring.

In the embodiment of FIG. 1, the electrode for applying the electric field is vibrated to vibrate the ER fluid, and in the embodiment of FIG. 6, the work part to be treated is vibrated. in short,
It suffices to perform relative vibration so as to generate a frictional force between the surface of the work part to be finished and the ER fluid in contact therewith. On the other hand, in all the examples so far, ER
The electric field applied to the fluid was arranged to be parallel to the surface of the work piece to be polished. However, surface treatment can also be performed by applying an electric field in a direction orthogonal to this.

FIG. 7 shows such an embodiment. An ER fluid 71 is filled between the electrodes 72 and 73 arranged in parallel, and a plate body 74 which is a machined component to be subjected to finish polishing of the surface is placed in the ER fluid 71 while being supported by the electrode 73. Then, while supplying electric power from the power source 75 to the electrodes 72, 73, the plate 74 is reciprocally oscillated as shown by an arrow parallel to the surface thereof.

In the case of this embodiment, the chain-like clusters formed in the ER fluid 71 are perpendicular to the surface of the plate 74. Therefore, when the plate body 74 is vibrated, a large number of clusters serve as polishing brushes to exert a frictional force on the surface of the plate body 74, and surface finishing polishing is performed.

FIG. 8 shows still another embodiment of the present invention. In this embodiment, an ER fluid 82 in which ferromagnetic particles are dispersed at the same time as dielectric particles is used to apply an electric field and a magnetic field at the same time to polish a processed part. Magnetite powder or the like is used as the ferromagnetic fine particles. Similar to the embodiment of FIG. 6, the container 81 is filled with the ER fluid 82, and the plate body 85 to be finish-polished is dipped therein. The parallel electrodes 86 and 87 are arranged in the ER fluid 82 so as to sandwich the plate body 85 from the lateral direction, and the power source 88 is connected thereto. Further, the S pole 84 of the magnet is arranged at the bottom of the container 81, that is, below the plate body 85, and the N pole 83 is arranged above the plate body 85.

In this way, the plate body 85 is added to the ER fluid 82.
At the same time as applying an electric field parallel to the surface to be polished, the magnetic pole is rotated within a predetermined angle range as indicated by an arc-shaped arrow in FIG.
Give a linear reciprocating vibration to. As a result, the surface of the plate body 85 is well polished by the synergistic effect of the surface treatment effect of the dielectric fine particles in the ER fluid 82 and the surface treatment effect of the ferromagnetic fine particles.

This embodiment is a combination of the polishing and the magnetic polishing methods utilizing the ER effect, and since the magnetic field enters as a parameter in addition to the electric field, the surface treatment conditions are highly diverse. Therefore, it is not limited to the surface finish of the plate,
In addition to the inner surface processing of the through pores described in the embodiment of FIG. 1 and the deburring of the inside of the minute pipe described in the embodiment of FIG. 6, finish polishing of complicated curved surfaces and spherical surfaces of various precision machined parts, precision rounding It can be applied to processing such as attachment.

In the above embodiments, the ER fluid is mechanically vibrated at the same time as the AC electric field, but it is also possible to vibrate the fine particles in the ER fluid only by the AC electric field without applying mechanical vibration. In particular, when the AC electric field to be applied is a low-frequency electric field of about 10 Hz, there is a delay in the polarization of the dielectric particles in the ER fluid, that is, a delay with respect to the electric field change of the electric dipole formation. The difference causes the electric force to act between the particles, and FIG.
Vibration can be caused by a slight state transition between the state of (a) and the state of (b) in the figure.

[0032]

As described above, according to the present invention, E
When an electric field is applied to the R fluid, a cluster of dispersed fine particles connected in a chain is used as an abrasive to generate a relative vibration that causes a frictional force between the ER fluid and the surface of the machined part to be finished. Given that, it is possible to finish the through-pores and the inner surface of a small pipe, which are difficult in the past. Further, according to the present invention, an ER fluid in which ferromagnetic fine particles are dispersed together with dielectric fine particles is used, and an electric field and a magnetic field are applied to the ER fluid and vibration is applied thereto, thereby exerting a frictional force between the dielectric fine particles and the ferromagnetic fine particles. As a result, effective surface finishing processing becomes possible, and a variety of surface finishing processing conditions can be realized by increasing parameters.

[Brief description of the drawings]

FIG. 1 shows a method of treating a cap according to an embodiment of the present invention.

FIG. 2 shows a state of medium dispersion of an ER fluid in the same example.

FIG. 3 is an enlarged view showing a state of inner surface treatment of a through-hole according to the same embodiment.

FIG. 4 shows a processing method of another embodiment of the present invention.

FIG. 5 shows a processing method according to still another embodiment of the present invention.

FIG. 6 shows a processing method according to still another embodiment of the present invention.

FIG. 7 shows a polishing method according to still another embodiment of the present invention.

FIG. 8 shows a polishing method according to still another embodiment of the present invention.

FIG. 9 shows a limiting current type ceramic oxygen sensor.

FIG. 10 shows how burrs are formed by pipe processing.

[Explanation of symbols]

11 ... Ceramic cap, 12 ... Through pores, 13 ... E
R fluid, 14, 15 ... Electrode, 16 ... Power supply, 17 ... Electrode support member, 18 ... Vibrator, 13a ... Insulating solvent, 13b ...
Whiskers (dielectric fine particles), 13c ... Cluster, 35
... Containers, 52 ... Support trays, 53, 62, 71, 82 ...
ER fluid, 54, 63 ... Rod, 55, 56, 67, 6
8, 72, 73, 86, 87 ... Electrodes, 57, 69, 7
5, 88 ... Power source, 65 ... Pipe, 74, 85 ... Plate, 8
3 ... N pole, 84 ... S pole.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinzo Nishimura 11 Akita Prefectural Industrial Technology Center, 4-4, Sunaya, Shinya, Akita City, Akita Prefecture

Claims (4)

[Claims] 1. A surface of a machined component to be subjected to a finishing treatment is immersed in an electrorheological fluid in which dielectric particles are dispersed in an insulating solvent, and an electric field is applied to the electrorheological fluid. A surface finishing method comprising applying a vibration that causes a frictional force between the machined part and a surface to be finished. 2. An electrorheological fluid in which at least a surface of a machined part to be subjected to finishing treatment is dispersed in an insulating solvent in which dielectric particles and ferromagnetic particles are dispersed, and an electric field and a magnetic field are applied to the electrorheological fluid. A surface finishing treatment method is characterized in that a vibration that causes a frictional force is applied between the electrorheological fluid and the surface of the machined component to be finished. 3. The surface finishing treatment method according to claim 1, wherein the electric field applied to the electrorheological fluid is in a direction parallel to a surface of the machined component to be finished. 4. The surface finishing treatment method according to claim 1, wherein the vibration is externally applied as mechanical vibration between the electrorheological fluid and the machined component.