JPH04117212U - Hydrostatic bearing device - Google Patents

Abstract

(57) [Summary] [Purpose] In a hydrostatic bearing device, to facilitate manufacturing of a pocket portion including a throttle hole for ejecting fluid and a surface throttle, improve processing accuracy, and reduce variations in rigidity values. [Structure] The pocket part including the aperture hole and the surface aperture is created separately and combined with the main body.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention is held in a bearing in a machine element using air pressure, water pressure, or hydraulic pressure. The structure is a hydrostatic bearing device.

0002

[Conventional technology]

Traditionally, hydrostatic bearing devices, which are held by air, water or hydraulic pressure, have no friction or wear. It is known that smooth characteristics can be obtained.

0003 For example, the air slide shown in FIG. 6 allows the sliding body 1 to move on the guide shaft 2. The slider 1 is supported and air is blown out from the sliding body 1 into the gap between the two. In addition, the sliding body 1 has four base plates fixed with bolts, of which As shown in FIGS. 7 and 8, a plurality of pockets 21 are formed in the base plate 20. This pocket 21 has a restriction hole that blows out air from the air passage hole 24. 22, and a surface aperture 23 consisting of a square-shaped groove, and the bases of each other are It had bolt holes 25 for fastening the base plate 20 with bolts.

0004 Generally, in order to support with static pressure, a plurality of pockets 21 are formed, and the inside of these pockets 21 are formed. Although it is necessary to keep the pressure constant, there is a restriction hole 22 between the air passage hole 24 and the pocket 21. is formed, the pressure inside one pocket 21 decreases due to external force. Also, the pressure drop on the air passage hole 24 side can be suppressed to a small amount. Therefore, other pockets 21 pressure drop is also suppressed, and support by static pressure continues. Therefore, In order to provide stable support, the number of pockets 21 must be as large as possible, and the number of pockets 21 must be It is preferable that the shapes of the holes 22 and the surface apertures 23 are well-balanced.

[0005] Moreover, this base plate 20 is integrally formed of ceramics such as alumina. Therefore, when manufacturing the shape of the pocket 21, the depth of the surface drawing 23 should be several tens of microns. Because of its small size, it is suitable for milling, etching, and blasting (abrasive injection). processing) etc. Note that the aperture hole 22 has a diameter of about 100 μm. Since it is small and difficult to process directly, a separate chip with aperture hole 22 is made and connected. The method used was to fix it with adhesive.

[0006]

[Problem that the idea aims to solve]

However, the conventional hydrostatic bearing device as described above has the following problems. 1) If the pocket 21 is processed by etching or blasting, it will be approximately ±20 μm. The limit is accuracy, and the shape of the surface aperture 23 is formed in a well-balanced manner with an accuracy of several μm. I couldn't. Therefore, variations in partial stiffness when an unbalanced load is applied There was a problem in that the force was large and the overall rigidity decreased accordingly.

[0007] 2) In addition, if the pocket 21 is processed by milling, a large amount of machining is required. This is a major factor in the high cost of the entire hydrostatic bearing device. Furthermore, this Even in this case, the machining accuracy is limited to about ±5μm, and there are large variations in partial stiffness. Ta.

[0008] 3) Furthermore, in the manufacturing process of the hydrostatic bearing device, the base plate 2 including the pocket 21 is Since the entire part 0 is machined as one piece, and the aperture hole 22 is machined separately and glued, many The number of steps required was a factor in high costs. 4) If a processing defect occurs in even one part of the pocket 21, the entire base plate 20 will be defective. As a result, the yield was poor.

[0009]

[Means to solve the problem]

In view of the above, in the present invention, in the base plate of the sliding body constituting the hydrostatic bearing device, , the pocket part including the aperture hole and surface aperture is formed separately from the base plate body. After that, it is connected to the base plate body.

0010

[Effect]

According to the present invention, since only the pocket part is manufactured separately, the aperture hole and the front The shape of the face drawing has been standardized, improving shape accuracy, and making it possible to configure a large number of pockets. This makes it easier to improve the rigidity characteristics of hydrostatic bearing devices and reduce variations in partial rigidity. can be suppressed. In addition, when forming the pocket part with ceramics, It became possible to use press forming for the shape method, making it easy to mass produce. can reduce costs.

[0011]

【Example】

Hereinafter, embodiments of the present invention will be explained with reference to the drawings. As shown in FIG. 6, the air slide, which is an embodiment of the present invention, has a guide shaft 2 and It consists of a sliding body 1 supported on this guide shaft 2, and the gap between the two is It is designed to blow out air.

0012 The above-mentioned sliding body 1 is composed of four base plates, but a perspective view of only the base plates is shown in Figure 1. This base plate 10 consists of a pocket member 11 and a base plate main body 15. The pocket member 11 is formed with an aperture nozzle 12 and a surface aperture 13. There is. In addition, the base plate main body 15 has an air passage hole 16 and other base plate 10. A bolt hole 17 for fastening is formed. Furthermore, as shown in the cross section in Figure 2, The pocket member 11 is glued to the base plate main body 15, and the air passage hole 16 and the aperture nozzle are connected to each other. The nozzle 12 is configured to communicate with the air supplied through the air passage hole 16. The air is blown out from the throttle hole 12.

[0013] In addition, as shown in FIG. 3(A), another example is a pocket portion of the base plate main body 15. A recess 18 is formed in the part where the material 11 is attached, and a pocket is inserted into this recess 18. By adhering the contact member 11, positioning can be facilitated.

[0014] Furthermore, as shown in FIG. 3(B) in another embodiment, the air conduction of the base plate body 15 is The holes 16 are groove-shaped, and the end surfaces of the flanges 14 formed on each pocket member 11 are the same. It is also possible to have a structure in which the air conduction holes 16 are bonded together so as to cover the air conduction holes 16. Ru. With this structure, the base plate main body 15 can be easily manufactured.

[0015] The pocket member 11 may be made of various materials such as alumina and zirconia. It is made of ceramics made by molding ceramic raw powder using a press molding method. At this time, if the aperture hole 12 and surface aperture 13 are formed depending on the shape of the mold, it is easy to It can be manufactured with high precision. Furthermore, the base plate body 15 is also made of ceramics. It is desirable to use cast molding because it is a relatively large product, but the shape is simple. It is easy to manufacture.

[0016] In this way, by manufacturing the pocket member 11 as a separate body, manufacturing is easy. In addition, high precision can be achieved, and yield can also be improved.

[0017] In addition, in the above embodiment, the air slide in the linear direction shown in FIG. However, even an air bearing in the rotational direction can have a similar structure. example For example, as shown in FIG. The pocket members 11 are formed into a shape and rotated by arranging the pocket members 11 adjacently in an arc shape. A hydrostatic bearing in the thrust direction of the shaft can be constructed. Also, as shown in Figure 5 , the pocket member 11 having the aperture hole 12 and the surface aperture 13 is shaped into a curved surface (tile shape). By arranging the pocket members 11 adjacently in a cylindrical shape, the axis of rotation can be adjusted. A radial hydrostatic bearing can also be constructed.

[0018]Experimental example Here, a base plate 10 shown in FIGS. 1 and 2 was prototyped as a hydrostatic bearing device of the present invention. , assembled an air slide. In addition, as a comparative example, the base plate shown in FIGS. 7 and 8 A conventional air slide using 20 was prepared and an experiment was conducted to compare the performance. stomach In both cases, the guide shaft and sliding body are made of alumina ceramics, and the guide shaft cross section is large. The size is 60 x 60 mm, the width of the sliding body is 150 mm, and the supply air pressure is 4 kg/cm. ² The rigidity of each part on the upper surface of the sliding body was measured.

[0019] Table 1 shows an air slide with pockets processed by blasting (Comparative Example 1) Partial rigidity table, Table 2 shows the air slide (with pockets processed by milling). It is a partial rigidity table of Comparative Example 2). From these results, Comparative Example 1 shows that the variation in rigidity is Ki (±2σ) is large at 1.2 kg/μm or more, and the stiffness value itself is 5.96 k at the center. It was as low as g/μm. Also, in Comparative Example 2, the rigidity variation (±2σ) was 0.5 kg/μm or more, and the stiffness value itself was low at 6.26 kg/μm at the center.

[0020] On the other hand, the partial stiffness table for the air slide of this invention is as shown in Table 3. , the rigidity variation (±2σ) is small at 0.4 kg/μm or less, and the rigidity value is also in the center. It was as high as 9.66 kg/μm.

[0021]

[Table 1] Comparative example 1

[0022]

[Table 2] Comparative example 2

[0023]

[Table 3] Examples of the present invention

[0024] Next, the manufacturing processes of the present invention and a comparative example were compared. First, the manufacturing process of the comparative example As shown below, it requires many steps and takes a long time (man-hours). I understand. Especially 8. wrapping process, 9. Pocket grooving requires a large amount of man-hours. I'm lifting weights. In addition, the number of man-hours is the value obtained by dividing the total processing cost by the time cost per person. It is.

Comparative Example 1. Preparation of ceramic raw materials 0.48 hours 2. Large-frame molding of parts (rubber press, casting molding, etc.) 1.21 3. Drying 0.21 4. Raw cutting (cutting unnecessary areas in advance) (drilling, grooving) 1.88 5. Firing 1.55 6. Adhesion and curing of orifice hole tips and nut bushes 2.22 7. Grinding (forming to an accuracy of about ±5 μm) 1.32 8. Lapping processing (manual processing to an accuracy of ±1 μm or less) 3.24 9. Pocket grooving (diamond milling) 4.22 10. Slide assembly 1.56 11. Measurement, lap adjustment 2.45 total 30.34

[0026] Next, the processing steps and the number of man-hours of the present invention are as follows. Example of the above integral processing It can be seen that the number of man-hours was reduced to less than 1/3, which was a significant improvement.

Present invention 1. Preparation of ceramic raw materials 0.48 hours 2. Large frame molding of parts (casting molding) 0.44 3. Dry 0.18 4. Press molding of drawing nozzle 0.08 5. Firing 1.65 6. Nut bush adhesion/curing 1.68 7. Grinding (forming to an accuracy of about ±5 μm) 0.44 8. Grinding, lapping, and mounting of the aperture nozzle 0.34 9. Slide assembly 1.56 10. Measurement, lap adjustment 2.45 total 9.30

[0028]

[Effect of the idea]

As described above, according to the present invention, the base plate constituting the sliding body of the hydrostatic bearing device is The pocket member including the aperture hole and the surface aperture is formed separately, and the base plate is By adopting a structure that is connected to the main body, the aperture hole and surface aperture, which have a complex structure, can be avoided. can be processed easily and with high precision, and the number of pockets can be increased. Wear. Therefore, the rigidity, which is a basic characteristic of a hydrostatic bearing device, is increased by 1.5 times or more, and the Since the partial rigidity is also stable, it can be used in applications with large loads. It is used in ultra-precise measuring and processing machines. Also, will the manufacturing man-hours be shortened? This makes it possible to reduce costs and supply highly accurate products at low prices. It can have many effects.

[Brief explanation of drawings]

FIG. 1 is a perspective view of only a base plate constituting an air slide which is an embodiment of the hydrostatic bearing device of the present invention.

FIG. 2 is a sectional view taken along the line XX in FIG. 1;

3A and 3B are sectional views showing other embodiments of the present invention corresponding to FIG. 2, respectively;

FIG. 4 is a schematic diagram showing a thrust direction bearing of an air bearing according to another embodiment of the present invention.

FIG. 5 is a schematic diagram showing a radial bearing of an air bearing according to another embodiment of the present invention.

FIG. 6 is a perspective view showing an air slide that is an example of a hydrostatic bearing device.

FIG. 7 is a perspective view of only a base plate constituting a conventional air slide.

8 is a sectional view taken along the line Y-Y in FIG. 7. FIG.

[Explanation of symbols]

1 Sliding body 2 Guide shaft 10 Base plate 11 Pocket member 12 Aperture hole 13 Surface aperture 15 Base plate body 16 Air conduction hole

Claims (1)

[Scope of utility model registration request] 1. A hydrostatic bearing device configured to eject hydrostatic fluid from a throttle hole, characterized in that a separately formed pocket member having the throttle hole is coupled to a main body. .