JPH07223163A - Working method for groove - Google Patents

Abstract

PURPOSE:To provide a working method for a groove which is effective in viewpoints of arrangement, working precision, automatization, and manufacturing cost. CONSTITUTION:A rubber elastic thin film 101 is formed on the whole surface area of a base material 100, the thin film 101 in the area of a prescribed pattern 105 is removed to expose the surface of the base material 100, hard fine particles are injected onto the surface to corrode the surface of the base material 100, and the remaining thin film 101 is then further removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a groove processing method,
For example, it is applied to the processing of seal grooves and the like. Further, the present invention can be applied to processing of a lubricating oil supply groove to a sliding portion, a fine liquid constant supply groove, and the like.

[0002]

2. Description of the Related Art A bearing seal mechanism of a compressor is required to ensure a reliable seal under a pressure change. The dry gas seal system has the following features and is therefore more promising than the conventional oil film seal system and mechanical seal system.

(1) Since the dry gas seal is a non-contact seal in which gas is interposed, the mechanical loss is extremely small. (2) A seal oil pump and a drive source from the outside are not required, so that downsizing and energy saving can be achieved, and initial cost, running cost, maintenance cost and installation space can be reduced. (3) High peripheral speed and high pressure can be supported. (4) Since it is a non-contact seal, it has no wear, is highly reliable, and has a long life.

The basic structure of a dry gas seal is shown in FIG. This example is for a compressor. As shown in the figure, the rotary ring 3 is attached to the rotary shaft 3 via a pair of sleeps 4 and 5.
Is fixed and a stop ring 2 is held by a seal case 6 attached to a housing surrounding the rotary shaft 3, and the stop ring 2 is pressed toward the rotary ring 1 side by a spring 7. The rotary ring 1 and the stop ring 2 constitute a seal portion, which seals between the inside of the high-pressure machine and the side of the low-pressure atmosphere.

An enlarged view of the seal portion is shown in FIG. As shown in the figure, the shaft sealing surface of the stop ring 2 is provided with a circumferential groove 10, and a seal gas supply hole 11 communicating the circumferential groove 10 to the inside of the machine is provided in the circumferential direction of the stop ring 2. A plurality is provided. On the other hand, on the sealing surface of the rotary ring 1, as shown in FIGS. 7 and 8, a plurality of spiral grooves 12 are provided so as to partially overlap the portion facing the circumferential groove 10. Stationary ring 2
A portion inside the circumferential groove 10 is a sliding seal surface 14, and a portion inside the portion of the rotary ring 1 facing the circumferential groove 10 is a sliding seal surface 13.

Therefore, at rest, as shown in FIG.
Since the forces F ₁ and F ₂ act in the closing direction between the stationary ring 2 and the rotating ring 1, the sliding seal surfaces 13 of the rotating ring 1 and the stationary ring 2,
14 make contact and the gas is sealed. Further, during operation, the seal gas supplied from the seal gas supply hole 11 to the circumferential groove 10 is pushed toward the outer peripheral portion of the spiral groove 12 from the circumferential groove 10 with the rotation, so that as shown in FIG. The dynamic pressure that levitates the stationary ring 2 is generated, and the stationary ring 2
A gap 15 will be formed between the rotary ring 1 and the rotary ring 1.

Although the seal gas leaks from the gap 15 to the low pressure side, since the gap 15 is as small as several μm, the leak amount of the seal gas is extremely small. In FIG. 6, 8 is a tolerance ring and 9 is an O-ring.

[0008]

By the way, the spiral groove 12 arranged on the shaft sealing surface of the rotary ring 1 constituting one of the above-mentioned sealing structures is three-dimensional, highly accurate and complicated. In particular, the depth d of the spiral groove is the factor that most affects the sealing function. Usually, the depth d is 3 to 8 μm, and the variation must be finished to about ± 1 μm. As the material, carbides such as tungsten carbide (WC) and silicon carbide (SiC), powder alloys in which these high hardness substances are dispersed and strengthened, and cermets are used.

As a method of manufacturing such a rotary ring 1,
Conventionally, photochemical etching is used,
This method has the following problems. (1) Since the base material of the rotary ring has high etching resistance, it takes a long time for etching. In other words, productivity is low. (2) It is necessary to change the type of the etching solution every time the type of the base material of the rotary ring is changed, and it is difficult to secure the stability of the groove depth accuracy, which complicates the production control. (3) Since the base material of the rotary ring has high etching resistance, the resist film applied to the surface of the base material is also easily damaged, the accuracy of the spiral groove is lowered, the yield is poor, the cost is high, and the sealing performance is high. It also affects stability.

Therefore, the present inventor has already proposed an ultrasonic processing method shown in FIGS. 11 and 12 in order to solve the above-mentioned problems (1993 Japanese Patent Application No. 275177). This ultrasonic machining method is a method of ultrasonic machining using a tool having a cross-sectional shape that is the same as the planar (two-dimensional) profile of the groove.

That is, as shown in FIG. 12, the ultrasonic machining tool 24, which is an electrode, has a plurality of machining tools 32 arranged at the base end 31 on the same circumference and at the center of the base end 31. The dummy tool 33 is arranged, and ultrasonic vibrations from an oscillator (not shown) are transmitted to the ultrasonic machining tool 24. Each machining tool 32 on the circumference has a cross-sectional shape that is substantially the same shape as the spiral groove 12 to be machined, and is arranged so as to match the spiral groove 12 arranged in the rotary ring 1.

As shown in FIG. 11, the central dummy tool 33 has a cylindrical shape and a through hole 34 is formed in the center thereof, and a mandrel 35 is slidably inserted into the through hole 34. . A hard material 36 is attached to the tip of the mandrel 35, and a collar-shaped projection 38 having a notch 37 is formed on the rear end side thereof. The dummy tool 33 is attached to an oscillator (not shown) via the horn 23.
3 and the collar-like protrusion 38 of the mandrel 35 between the spring 41.
Is pushed in and the mandrel 35 is always biased toward the tip side. Further, a sensor 42, which is a displacement strain plate, is attached to the notch 37 of the flange-shaped projection 38, and the displacement of the mandrel 35 can be detected.

Therefore, while supplying the machining liquid in which the abrasive grains are dispersed between the ultrasonic machining tool 24 and the rotary ring 1, the ultrasonic machining tool 2 is supplied from the oscillator (not shown) through the horn 23.
By applying ultrasonic vibration to 4, the surface of the rotary ring 1 is finely broken and the spiral groove 12 is processed. As the machining progresses, the tips of the machining tool 32 and the dummy tool 33 wear, but the hard material 36 attached to the tip of the mandrel 35.
Does not wear, the amount of wear of the tip of the processing tool 32 can be grasped by measuring the displacement of the mandrel 35 with the sensor 42. Then, based on the wear amount of the tip of the processing tool 32,
The ultrasonic processing of the spiral groove is performed while obtaining the depth h of the groove 44 being processed.

However, the ultrasonic machining method described above is
The number of man-hours required to manufacture the tool corresponding to the shape of the product groove is large, and the economy is low in terms of product cost. In view of the above-mentioned technique, the present invention has been completed by combining various preliminary tests and utilization of conventional techniques, and provides a groove processing method effective in terms of setup, processing accuracy, automation, and manufacturing cost. The purpose is to

That is, according to the present invention, the material of the rotating ring material having the highest hardness is WC (tungsten carbide, H _v = 2400), and a ceramic fine powder which is softer and cheaper than this, for example,
Al ₂ O ₃ (aluminum oxide, H _v = 2100, particle size: 0.5-10 μm)
However, by injecting Al ₂ O ₃ fine powder into a hard WC at a high speed, it is possible to easily erode mechanically and physically, and it is extremely eroded to an elastic body such as rubber or plastic. It was completed by focusing on difficult facts.

[0016]

[Means for Solving the Problems] According to the structure of the present invention for achieving such an object, after forming a thin film of a rubber-like elastic material on the entire surface of a base material, the thin film in a predetermined pattern region is removed. The base material surface is exposed, and then hard fine powder particles are ejected onto the surface to erode the base material surface,
Further, the remaining thin film is removed. Here, the surface of the base material may be two-dimensional like a base material of a rotary ring, and the predetermined pattern may be a pattern corresponding to a spiral groove.

Further, the surface of the base material is three-dimensional like a work material in which a taper portion is formed between shaft portions having different shaft diameters,
The predetermined pattern may be a pattern formed in a spiral shape on the tapered portion. Further, the removal of the predetermined pattern region of the thin film can be performed by a photoresist method or by irradiation with laser light.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the drawings. One embodiment of the present invention is shown in FIG.
2,5. In this embodiment, a conventionally known photoresist method is used as a method for designing the groove pattern provided on the surface of the rotary ring.

First, as shown in FIG. 1 (a), the thoroughly degreased and washed rotating ring base material 100 is dipped in a photosensitive resist solution, and then pulled up at a low speed to apply and dry a resist film 101. Next, as shown in FIG. 1B, a film 103 is further adhered on the resist film 101,
Light is emitted from the light source 102 to expose the resist film 101. As shown in FIG. 2, the film 103 has a black opaque groove pattern 104 drawn on a transparent film.

Then, as shown in FIG. 1C, development,
The resist film 101 is fixed and dried.
Are classified into a photosensitive portion 101a and an unexposed portion 101b. At this time, the resist film 101 becomes an elastic thin film that exhibits rubber elasticity. Subsequently, as shown in FIG. 1D, the unexposed portion 101b is immersed in a removing solution to completely remove the unexposed portion 101b to expose the predetermined pattern 105, and then dried. The predetermined pattern 105 is an area where the rotary ring base material 100 is exposed, and corresponds to the groove pattern 104 shown in FIG.

As described above, the resist film 101 in the region to be processed of the rotary ring base material 100 is removed by the photoresist method to form the predetermined pattern 105, and the adhesion is high with respect to the unprocessed portion, and The resist film 101, which is a thin film of a rubber-like elastic body, can be formed. The film (negative film) 103 used in the photoresist method is
Since it is inexpensive and can be manufactured in a short time, it contributes to shortening the delivery date and cost. Further, the groove-shaped tool which is required in the conventional ultrasonic machining method is not required.

Further, as shown in FIG. 5, hard fine powder particles are jetted to the rotating ring base material 100 on which the resist film is formed under a predetermined condition for a predetermined time to erode the area of the predetermined pattern 105. Forming a spiral groove.
That is, the rotating ring base material 100 on which the resist film 101 is formed
Is installed on the rotary table 124 in the micro blaster main body 120, and the hard fine powder particles (abrasive particles) 121 are ejected from the nozzle 122 via the high-speed air 123. The area of the predetermined pattern 105 of the rotary ring base material 100, that is,
The exposed portion of the base material to be processed is the abrasive grains 12 that are transported by gas.
1 is rubbed and polished, and is eroded along the pattern shape. On the other hand, the portion covered with the resist film 101 is hardly abraded and is not eroded even if it is sprayed with the abrasive grains 121 because of its rubber-like elasticity.

As a result, a minute step is formed on the front surface between the portion covered with the resist film 101 and the base material exposed portion, and the base material exposed portion is formed with a uniformly eroded pattern groove. . As described above, since the unprocessed portion of the rotary ring base material 100 is covered with the resist film 101, even if the abrasive grains 121 are jetted, it is less likely to be damaged. The unneeded portion of the rotary ring base material 100 is mirror-finished to 0.2 μm or less. Rotating ring base material 10 on which pattern grooves are formed
From 0, the resist film 101 is thereafter removed. In FIG. 5, 125 is a recovery hopper, 126 is a recovery tank, 127 is a shield plate, 128 is a duct hose, and 129 is a filter.

In this way, since hard fine powder particles are jetted (called micro-blasting) to carry out groove processing,
There is no liquid change, resist film dissolution, or erosion due to the material change of the work material such as conventional photochemical etching,
Grooving productivity and pattern shape dimensional accuracy are greatly improved. Particularly, since the resist film 101 having high adhesion and rubber elasticity is adopted, peeling and damage of the resist film during microblasting can be prevented.

A second embodiment of the present invention is shown in FIGS.
In the present embodiment, laser beam irradiation is used as a method for designing a groove pattern provided on the surface of the rotary ring. First, as shown in FIG. 1A, the fully degreased and washed rotating ring base material 100 is dipped in a resist solution (not necessarily photosensitive), and then pulled up at a low speed to apply a resist film 101. dry. The resist film 101 is an elastic thin film having rubber elasticity.

Next, as shown in FIGS. 3 and 4, the rotating ring base material 100 on which the resist film 101 is formed is placed on the XY table 106, and excimer laser light 110 is emitted from the excimer laser 113. The entire area of the predetermined pattern of the rotating ring base material 100 is irradiated, and the predetermined pattern 105 of the resist film 101 is vaporized and removed to be removed. The excimer laser 113 follows the position coordinates of the pattern calculated in advance,
Excimer laser light 110 driven by numerical control (NC)
Is irradiated in a predetermined pattern of the resist film 101 in a scanning manner to remove the resist film 101 and expose the surface of the base material.
In FIG. 3, 111 is vaporized gas and 114 is alignment He.
A Ne laser, 115 a mirror, 116 a field lens, 117 an imaging lens, 118 a half mirror, and 119 a monitor CCD camera.

As described above, by irradiating the laser beam, the resist film 101 in the region to be processed of the rotary ring base material 100 is removed to form the predetermined pattern 105, and the adhesion is high with respect to the unnecessary portions. Moreover, the resist film 101, which is a thin film of a rubber-like elastic body, can be formed.

As described above, in this embodiment, the resist film 101 is irradiated by the numerically controlled irradiation of the excimer laser light 110.
Since the predetermined pattern 105 can be removed by evaporation, the process can be omitted as compared with the photoresist method, and CAD (computer-aided design) data can be directly connected to scan an excimer laser gun driven by NC. / CAM (computer-aided processing) can be achieved, and it is possible to significantly reduce costs and shorten the construction period.

Subsequently, as in the embodiment described above, FIG.
As shown in FIG. 5, the region of the predetermined pattern 105 of the rotary ring base material 100, that is, the base material exposed portion to be processed is rubbed and polished by the abrasive particles 121 that are gas-transferred by micro-blasting, and the pattern shape is followed. To erode.

Next, a more specific embodiment 1 of the present invention
2 and 3 will be described. Example 1 In this example, a diameter of 170 mm and a thickness of 12
A spiral groove having a depth of 5 μm (+1.5 μm, −0.5 μm), an outer edge radius R _o = 72 mm, and an inner edge radius R _i = 66 mm is formed at a pitch of 15 ° on the surface of a rotary ring material made of tungsten carbide of mm. 24 pieces are arrayed on the circumference (see FIG. 8). First, after mirror-polishing the upper surface of the rotating ring, degreasing, cleaning, and drying in an ultrasonic cleaning tank, and then dipping, pulling, and drying in the photosensitive resist material solution in a dark room, repeating 3 times, and then rotating on the rotating ring. A resist film was formed (see FIG. 1 (a)).

After that, the film was brought into close contact with the rotating ring base material and irradiated with light from a light source to expose the resist film in a pattern (see FIG. 2B). This film has a black opaque groove pattern 104 on a transparent film.
Are formed (see FIG. 2). Then, the resist film is distinguished between the unexposed portion and the exposed portion by the developing / fixing liquid (see FIG. 1C). Then, soak in the removal solution,
The unexposed portion is removed, a predetermined pattern is exposed, and then dried (see FIG. 1D).

Further, a rotary ring base material having a pattern other than a predetermined pattern covered with a resist film is set on a rotary table in the main body of the micro blaster, and hard fine particles (abrasive particles) are jetted from a nozzle through high-speed air. (See FIG. 5). As the hard fine powder particles, aluminum oxide (Al ₂ O ₃ ) having a particle size distribution of 2 to 5 μm was sprayed at a spray pressure of 4.5 kgf / cm ² and a work distance (spray distance) of 60 mm. A depth of 5.6 to 5.9 is formed in a predetermined pattern region of the rotary ring base material.
A groove having a surface roughness of 0.23 μm was formed.

[Embodiment 2] In this embodiment, a rotary ring having the same specifications as in Embodiment 1 was manufactured in the following manner. First, the mirror-finished rotating ring base material was degreased and cleaned by ultrasonic cleaning. Next, in a bright place (not a dark place), dipping in a high-viscosity non-photosensitive resist material solution and drying are repeated twice, and the film thickness is about 5
A resist film having a rubber-like elasticity of 0 μm was formed.

After that, the rotary ring base material is placed on an XY table driven based on the position coordinates when the pattern groove is designed, and the laser light transmitted through the optical path from the excimer laser oscillator is scanned on the surface of the rotary base material. Irradiation is performed to evaporate and remove the resist film (see FIG. 3). The resist film becomes vaporized gas and an exposed portion is formed (see FIG. 4). Subsequently, as in Example 1, pattern grooves were formed by a micro blaster. The forming accuracy and the dimensional accuracy were the same as in Example 1.

[Embodiment 3] In this embodiment, as shown in FIG. 13, as an example of processing a groove on the surface of a three-dimensional base material, a truncated cone shape is formed between shaft portions 131 and 132 having different shaft diameters. The shallow groove is processed in the base material (workpiece) provided with the tapered portion 133. As shown in FIG. 14, the three-dimensional groove generation state is such that a multi-axis turning mechanism (not shown) is provided on the XY table 112, and the excimer laser beam 110 is turned while the base material is turned about the work turning axis 114. Is irradiated on the surface of the base material to vaporize and evaporate the resist film, thereby forming a predetermined pattern 105 corresponding to the spiral groove. The resist film evaporates as the vaporized gas 111. After that, according to the second embodiment, the spiral groove is processed along the predetermined pattern 105.

Applications of the member manufactured in this manner are, for example, a vacuum pump and a fluid constant-feed device. That is, by covering the outer circumference of the member with a casing through a certain clearance and rotating the member, the taper portion 133 is rotated.
Due to the centrifugal force generated in the spiral groove of
→ Liquid or gas is fed in the direction indicated by B.

[0037]

As described above in detail based on the embodiments, according to the present invention, a thin film of a rubber-like elastic material is formed on the entire surface of a two-dimensional or three-dimensional base material, and then a photoresist method is used. Alternatively, a thin film in a predetermined pattern region is removed by laser irradiation, and hard fine powder particles are jetted to the surface by microblasting to erode the surface of the base material, and then the remaining thin film is removed. For this reason, the conventional tool for groove machining required for ultrasonic machining becomes unnecessary. Especially since microblasting is used,
Unlike the conventional photochemical etching method, there is no change of liquid due to polarization of the material of the material to be processed, dissolution / erosion of the resist film, and the productivity of groove processing and the dimensional accuracy of the pattern shape are significantly improved. Also, in the case of the photoresist method, since only a film that can be manufactured at low cost in a short time is required,
Contributes to shorter delivery times and lower costs. Further, in the case of laser irradiation, compared with the photoresist method, the process can be omitted, and computer-aided design and computer-aided processing are possible, which further contributes to shortening the delivery period and cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a schematic procedure of forming a photoresist film used in a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a pattern film used in the first embodiment of the present invention.

FIG. 3 is a schematic diagram showing resist film formation by laser light according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a state of a resist film forming process by laser light in a second embodiment of the present invention.

FIG. 5 is a schematic view showing a situation in which microblasting is performed on a pattern exposed portion in the present invention.

FIG. 6 is a sectional view of a compressor according to a basic structure of a dry gas seal.

FIG. 7 is an enlarged view of a seal portion indicated by reference sign A in FIG.

FIG. 8 is a perspective view showing a three-dimensional structure of a part of a rotary ring.

FIG. 9 is an explanatory diagram showing a situation when the dry gas seal is stationary.

FIG. 10 is an explanatory diagram showing a situation during operation of the dry gas seal.

FIG. 11 is a cross-sectional view showing a groove processing state using an ultrasonic processing method.

FIG. 12 is an explanatory view showing a groove forming tool for a rotary ring in a conventional method.

FIG. 13 is an explanatory diagram showing groove processing according to another embodiment of the present invention.

FIG. 14 is an explanatory diagram showing a situation of a resist film forming process by laser light according to another embodiment of the present invention.

[Explanation of symbols]

 100 rotating ring base material 101 resist film 102 light source 103 film 104 groove pattern 105 predetermined pattern 106 XY table 110 excimer laser light 111 vaporized gas 112 XY table 113 excimer laser 114 alignment He-Ne laser 115 mirror 116 field lens 117 imaging lens 118 half Mirror 119 CCD camera for monitor 120 Micro blaster main body 121 Hard fine powder particles (abrasive grains) 122 Nozzle 123 High pressure air 124 Rotary table 125 Recovery hopper 126 Recovery tank 127 Shielding plate 128 Duct hose 129 Filter 131 Shaft part 132 Shaft part 133 Tapered part

Claims (7)

[Claims] 1. After forming a thin film of a rubber-like elastic material on the entire surface of the base material, the thin film in a predetermined pattern region is removed to expose the surface of the base material, and then the surface of the base material is exposed. A method for processing a groove, characterized in that hard fine powder particles are jetted to erode the surface of the base material, and the remaining thin film is removed. 2. The groove processing method according to claim 1, wherein the surface of the base material is two-dimensional. 3. The base material is a base material of a rotary ring, and
The groove processing method according to claim 2, wherein the predetermined pattern is a pattern corresponding to a spiral groove. 4. The method for processing a groove according to claim 1, wherein the surface of the base material is three-dimensional. 5. The base material is a material to be processed in which a tapered portion is formed between shaft portions having different shaft diameters, and the predetermined pattern is a pattern formed in a spiral shape on the tapered portion. The method for processing a groove according to claim 4. 6. A region of the thin film having a predetermined pattern is removed by a photoresist method.
Alternatively, the groove processing method described in 4. 7. The groove processing method according to claim 2, wherein the predetermined pattern region of the thin film is removed by evaporation by irradiation with laser light.