JPH086748B2 - Manufacturing method of porous hydrostatic gas bearing - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention has a porous body arranged on a bearing surface, and a pressurized gas is ejected from a ventilation hole of the porous body into a minute gap between the shaft and the shaft. The present invention relates to a method for manufacturing a porous hydrostatic gas bearing that forms a gas film to support a shaft.

[Prior Art] In order to obtain bearing performance such as predetermined rotation accuracy, load capacity, and bearing rigidity with this type of bearing, when a gas is supplied to the porous body at a predetermined pressure, It is required that the flow rate of the ejected gas, that is, the gas passage flow rate, be uniform over the entire bearing surface. Therefore, conventionally, the bearing surface was previously impregnated with resin so that the flow rate was not more than a predetermined value and the holes were closed, then the resin was appropriately removed by the solvent while measuring the gas passage flow rate, and the jet flow rate was made uniform. Was adjusted so that In this method, the bearing surface is rubbed with a cotton swab containing an appropriate amount of solvent to dissolve the resin, and the flow rate is gradually recovered to make repeated adjustments.

[Problems to be Solved by the Invention] However, in the conventional example, since the adjustment work depends on the experience and intuition of the operator, the adjustment method is performed by trial and error, resulting in a large number of work steps and a cause of cost increase. Becomes

Since it relies on manual work, it is difficult to standardize and the quality varies widely.

Not suitable for automation.

There was an inconvenience.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, reduces the working steps to reduce the manufacturing cost, can standardize the work and stabilize the quality, and can be automated. An object of the present invention is to provide a method for manufacturing a porous static pressure gas bearing.

[Means and Actions for Solving the Problems] The present invention applies a solvent to a resin-impregnated bearing surface through a pattern having even holes so that a gas passing flow rate of a gas bearing can be a predetermined value. The air flow rate on the bearing surface is measured in advance to determine whether it exceeds or falls below the standard flow rate, and the open pores on the bearing surface are restored according to the result of the determination. It is the one to choose whether to stop or to stop. The recovery of the open pores can be realized, for example, by applying a solvent to the gas bearing while supplying pressurized air. Further, the filling can be realized by applying the solvent in a non-air-supplied state.

[Example] FIG. 1 (a) is a sectional view showing a porous bearing, and FIG. 1 (b) is an external view thereof. In the figure, 1 is a graphite porous material, 2 is a housing for holding and fixing the porous material 1, 3 is an air supply chamber, and 4 is a compressed air supply port.

The gas passage flow rate of the porous material 1 finished to a predetermined accuracy by polishing or the like is manufactured so as to be larger than a design value. Therefore, this is matched with the design value according to the following procedure. First, the resin is impregnated into the fine open pores of the porous material 1. Excess resin covering the surface of the bearing surface is wiped off with a solvent, and a resin film 6a is formed in the open pores 5 as shown in FIG. As a result, the gas passage flow rate becomes smaller than the design value. Next, as shown in FIG. 3, the pattern 7 in which the small holes 7a are uniformly distributed so as to have a predetermined opening ratio is opposed to the bearing surface of the porous material 1 in parallel with a minute gap. Let me place it. Further, when a small amount of solvent is applied through the pattern 7 while the porous material 1 is ventilated, the resin impregnated in the porous material 1 corresponding to the positions of the small holes 7a of the pattern 7 melts and the predetermined amount is applied. The gas passage flow rate of is obtained. Here, as a method of applying the solvent, there is a method of atomizing and spraying. When applying the solvent, the open pores 5 can be opened (recovered) or closed (stopped) depending on whether or not pressurized air is supplied to the porous bearing.

In order to explain the adjustment principle of the gas flow rate in an easy-to-understand manner, FIGS. 4 (a), (b), (c), and (d) show cross-sectional views in which the open pores of the porous material are enlarged and modeled. .

Recovery of open pores The open pores 5 impregnated with the resin are blocked by the resin film 6b, and the resin film 6b is shown in FIG. 4 (a) when pressurized air is ventilated through the porous bearing. In addition, pressure is applied from the inside. In this state, the solvent that has passed through the pattern 7 reaches the bearing surface and then enters a part of the open pores 5 to dissolve the resin film 6b in the open pores 5. As a result, the resin film 6b is destroyed by the internal pressure as shown by 6c in FIG. 4 (b), and the pressurized gas flows out from the open pores 5. As a result, the open pores 5 are opened (recovered).

As shown in FIG. 4 (c), when the resin film 6d of the open pores 5 is destroyed by the solvent, regenerating the resin film to close the open pores 5 is called filling. When the solvent is sprayed to the porous bearing through the pattern 7 in the air-free state, the solvent 8 reaches the bearing surface and then penetrates into a part of the open pores 5 to melt the resin film 6d of the open pores 5. . The melted resin is regenerated by the surface tension into the complete resin film 6e again as shown in FIG. 4 (d) and instantly solidifies to close the open pores 5.

By opening and closing the open pores by these recovery and sealing treatments, and by changing the opening ratio of the pattern during the treatment to change the area to which the solvent is applied, the gas permeation flow rate of the bearing member can be changed. It can be uniformly set with a predetermined value.

Next, the actual method of adjusting the gas permeation flow rate will be described in detail. FIG. 5 is a block diagram showing a configuration of a flow rate adjusting device according to an embodiment of the present invention, and FIG. 6 is a flow chart showing a flow rate adjusting method in the device of FIG.
In FIG. 5, 101 is a compressor which is a supply source of compressed air, and 102 is a porous bearing which is intended to adjust the gas permeation flow rate. The porous bearing 102 is now connected to the compressor 101. 103 is a porous bearing 102 and a compressor 101
A three-way solenoid valve connected between and to control air supply to the porous bearing 102, 104 is a spray gun for applying a solvent to the surface of the porous bearing 102, and 105 is for supplying a solvent to the spray gun. Is a tank, 106 is a solenoid valve for controlling the air supply to the spray gun 104, and 107 is a driver for operating the solenoid valve 106. The solenoid valve 106 is connected between the spray gun 104 and the compressor 101. 108
Is a measurement pad for detecting the flow rate flowing out from the bearing surface 1 of the porous hydrostatic bearing 102, and 109 is a sensor for converting the detected flow rate taken in from the measurement pad into an electric signal. At the lower end of the measuring pad 108, as shown in FIG.
The rubber O-ring 120 is arranged, and the porous body 1 of the bearing 102 is arranged.
The air ejected from the surface of the sensor is guided to the sensor 109 through the guide hole 121. In FIG. 5, 110 is an A / D converter for converting the electric signal into a digital signal. Reference numeral 111 is a disk having a pattern for adjusting the application area of the solvent sprayed from the spray gun 104. Disk
111 is divided into six as shown in FIG. 7 (a),
The aperture ratio is 100%, 50%, 2 for each of the 6 parts.
Patterns 7f-7 set to 5%, 12%, 6% and 3%
k is formed. The pattern 7f is entirely composed of one opening. Each of the patterns 7 (7g to 7k) is formed by etching small holes 7a in a stainless steel plate having a plate thickness of about 0.1 mm at equal pitches, as shown in an enlarged view in FIG. 7 (b). Each pattern 7g ~
The 7k is manufactured to the specifications shown in Table 1.

In FIG. 5, 112 is a stepping motor for performing pattern indexing, 113 is a driver for driving the stepping motor, 114 is a CPU, 115 is a memory, and 116 is a driver for driving the three-way solenoid valve 103. is there.

 Next, the operation of the apparatus shown in FIG. 5 will be described.

When air is supplied to the porous bearing 102, the flow rate detection pad 108 is brought into close contact with the adjustment portion of the bearing surface to detect the gas passage flow rate. The detected flow rate is converted into an electric signal by the sensor 109, and is sent to the CPU 1 via the A / D converter 110.
Taken in 14. The CPU 114 determines whether to perform recovery or filling operation, and issues a command to the solenoid valve 103 to control the on / off of the supply air. Next, the CPU 114 performs a calculation for determining a pattern to be used for recovery or filling, and outputs a command according to the calculation result to the stepping motor driver 113. As a result, the stepping motor 112 is driven and the pattern 7 having a predetermined aperture ratio is selected.

Next, under the control of the CPU 114, the spray gun 104 is arranged at a fixed distance from the adjustment portion of the bearing surface. Then, a command is issued from the CPU 114 to the driver 107, and the solenoid valve 1
When 06 is turned on for a certain period of time, spray gun 104
Is supplied with air and sprays the solvent in a dew form from a nozzle.
The sprayed solvent is applied to the bearing surface via pattern 7 (any of 7f to 7k).

Next, the operation in the adjustment processing of the CPU 114 of FIG. 5 will be described based on the flow of FIG.

When the new porous bearing 102 is set as shown in FIG. 5, the CPU 114 resets the number of repetitions n (n = 0).
After that (step 600), the following adjustment process is executed.

First, the driver 116 sets the solenoid valve 103 to the porous bearing 102.
And the air supply from the compressor 101 to the bearing 102 is turned on (step 601). The sensor 109 detects the flow rate of the air jetted from the bearing surface of the porous bearing 102 to the detection pad 108 when the air supply is turned on. A / D converter 110
Converts this detected flow rate into a digital value Q _n . CPU114
Takes the detected flow rate value Q _n (step 602), the detected flow rate value Q _n determines whether to meet the design value _{(Q S = Q U ~Q L} ) ( step 603, 604). If the detected flow rate value Q _n is below the design lower limit value Q _L , to recover the flow rate,
The flow rate recovery loop on the right side of FIG. 6 is entered.

In this recovery loop, first, the number of repetitions n is determined (step 605), and if n = 0, a predetermined initial pattern (for example, pattern j) is selected (step 608). On the other hand, in the case of n ≧ 1, based on the relation between the detected flow rate value Q _n-1 taken at the time of this adjustment fetched in step 602 in the process detected flow value Q _n and the previous adjustment process, a pattern Select (step 606). Next, the solenoid valve 106 is turned on via the driver 107 to supply the compressed air from the compressor 101 to the spray gun 104. As a result, the solvent is sprayed from the spray gun 104 and applied to the bearing surface of the porous bearing 102 (step 607). And the number of repetitions n
After adding 1 to (step 609), the process returns to step 601, and the same operation as described above is repeated after the flow rate detection in step 602.

In the determination of step 603, 604 detecting the flow rate value Q _n If satisfied the range of the design value Q _S = Q _U ~Q _L completing this flow rate adjustment process. However, if event exceeds the upper limit value Q _U design, the resin film 6d of open pores 5 in order to reduce the flow rate below the design limit Q _U (Fig. 4 (c), (d)) to reproduce the To close the open pores 5 and enter the sealing loop on the left side of NO in FIG. 6 (the left side loop in FIG. 6).

In this filling loop, first, similarly to step 605 of the recovery loop, the number of repetitions n is determined (step 610). At this time, if n = 0, all the open pores 5 of the porous bearing 102 are blocked by the resin impregnation, and it cannot be stopped any further, so the operation is stopped as an error (step 611). ). If n ≧ 1, as in step 606 of the recovery loop, a predetermined pattern is selected according to the relationship between the detected flow rate values Q _n and Q _n-1 (step 612). Next, in order to reduce the flow rate, the solenoid valve 103 is controlled to stop the air supply to the porous static pressure bearing 102 (step 613). Further, the solvent is sprayed from the spray gun 104 and applied to the bearing surface (step 614). Then, after adding 1 to the number of repetitions n (step 616), the process returns to step 601 to control the solenoid valve 103 to supply air to the bearing again (step 601), and step 602.
The flow rate is detected. Hereinafter, the same processing as described above is repeated.

[Effects of the Invention] As described above, a predetermined gas flow rate can be obtained by applying a solvent through a pattern having a predetermined aperture ratio. Therefore, it is not necessary to repeatedly perform the adjustment work as in the related art, and the manufacturing cost is reduced. In addition, standardization of work is facilitated, quality is stabilized, and there is an effect that automation can be performed. Further, when the aperture ratio becomes excessively larger than the design value, it is possible to continue the filling process, which is effective in reducing the defective rate and improving the work efficiency.

[Brief description of drawings]

1 (a) and 1 (b) are a sectional view and a perspective view, respectively, of a porous bearing, FIG. 2 is an enlarged sectional view of a porous material impregnated with resin, and FIG. 3 is for solvent application. An external view showing an example of a pattern, FIGS. 4 (a) to 4 (d) are enlarged model explanatory views of the porous open pores of the present invention, FIG. 5 is a configuration diagram of a flow rate adjusting device according to the present invention, FIG. 6 is a flow chart showing flow rate adjustment in the apparatus of FIG. 5, and FIGS. 7 (a) and 7 (b) are external views of the disc having a pattern used in the apparatus of FIG. 5 and the circle, respectively. FIG. 8 is an enlarged view of the pattern on the plate, and FIG. 8 is an enlarged view of the flow rate measuring unit in the device of FIG. 1: Porous material 5: Open pores 6a, 6b, 6c, 6d, 6e: Resin film 7,7f to 7k: Pattern 7a: Small hole 8: Solvent 101: Compressor 102: Porous bearing 104: Spray gun 108: Measurement Pad 109: Sensor 111: Disc 114: CPU

Claims (3)

[Claims] 1. A porous material whose ejection flow rate is to be adjusted is impregnated with a resin to close open pores, and a solvent for dissolving the resin is applied to the porous material through a pattern having a predetermined opening distribution. In the method for manufacturing a porous hydrostatic gas bearing by adjusting the ejection flow rate of the porous hydrostatic gas bearing, by measuring the gas passage flow rate of the porous material prior to the solvent coating, it is a predetermined flow rate. A method of manufacturing a porous static pressure gas bearing, which comprises selectively using a flow rate adjusting method for recovering the open pores and a flow rate adjusting method for stopping the opening based on whether the flow rate is higher or lower. 2. A flow rate adjusting method for recovering the open pores,
A method of applying the solvent in a state in which a pressurized gas is supplied to the porous material, and a flow rate adjusting method for blocking the open pores is a method in which a pressurized gas is not supplied to the porous material. The method for producing a porous hydrostatic gas bearing according to claim 1, which is a method of applying a solvent. 3. The method for producing a porous hydrostatic gas bearing according to claim 1, wherein the solvent is applied in a state where the pattern is made to face a bearing made of a porous material in parallel at a predetermined interval.