JPH0710411B2 - FLUID BEARING MANUFACTURING METHOD AND FLUID BEARING BY THE METHOD - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a dynamic pressure fluid type thrust spiral groove bearing.

[Prior Art] The formation of the groove pattern of the conventional flat plate type spiral groove bearing was manufactured by cutting, and then by etching. Further, recently, it is manufactured by coining as shown in the patent application filed earlier by the inventor of the present application.

[Problems to be Solved by the Invention] In the case of cutting, the groove depth could not be stably cut unless the depth of the groove was as deep as several μm. The rigidity of the thrust spiral groove bearing tends to decrease as the groove depth increases. It is shown in the graph by exemplifying one calculation result in FIG. This graph was obtained under the following calculation conditions. That is, the groove angle is 20 °, the groove outer radius is 2.4 mm,
The groove inner radius is 0.5 mm, the number of grooves is 6, the groove width ratio is 1, the shaft rotation speed is 30 Hz, the load is 800 g, and the viscosity is 20 CP. Under these conditions, the groove depth (μm) was changed and the axial rigidity (g / μm) was calculated.

Recently, a compact and highly rigid thrust bearing has been required, and the groove depth has become about several μ, which makes it impossible to cope with cutting. Therefore, an etching method has recently been adopted instead of cutting, but this processing method requires many steps such as masking, etching, and masking removal of the groove pattern of the spiral groove, and has the disadvantage of high cost. there were. In addition, the surface roughness of the bottom surface of the groove due to the etching process is as rough as several μ, and the performance as a bearing is not stable.

In addition, when the groove pattern is formed by coining according to the patent application previously filed by the inventor of the present application, the processed flat plate is distorted in a convex shape toward the processed surface. It turns out that it has the drawback of becoming fierce.

The present invention has been made to solve the above problems, and the distortion can be suppressed by forming a pattern of the same area on the non-bearing surface side, and the performance of the thrust bearing is stabilized and the cost is reduced. The object is to obtain a processing method that can lower the

[Means for Solving the Problems] In the method for manufacturing a hydrodynamic bearing according to the present invention, a groove pattern is formed on the bearing surface side of the flat plate of the flat plate type thrust spiral groove bearing and a non-bearing surface side is formed by the closed coining process. This is a processing method of forming a pattern having the same area as the groove pattern.

[Operation] In the closed coining process of the flat plate spiral groove bearing according to the present invention, the convex warpage of the fluid bearing can be eliminated by simultaneously forming a pattern having the same area as the groove pattern on the non-bearing surface side. At the same time, it is suitable for mass production, contributes to cost reduction, and can supply high-performance bearings with stable quality.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, (1 ') is the material of the flat plate type spiral groove bearing before molding. A spiral groove pattern (5) is formed on the lower end surface of the upper punch (2), and a spiral groove pattern (5) is formed on the upper end surface of the lower punch (4).
A circular pattern (8) having the same area as is formed. A lubricant (7) is applied to the material (1 ') and held on a die (3), and a spiral groove pattern (5) and a spiral are formed by relative movement of the punch (2) and the lower punch (4). A circular pattern (8) having the same area as the groove pattern is transferred by compression onto both sides of the material (1 '). The figure schematically shows the main part of the processing machine by this closed coining method.

FIG. 2 shows a flat plate type spiral groove bearing (1) formed by the above embodiment. In this figure, a spiral groove pattern (6) and a circular pattern (9) having the same area as the spiral groove pattern (6) are formed. Further, the spiral groove pattern (5) of the upper punch (2) and the pattern (8) of the same area of the lower punch (4) formed on the material (1 ') are the patterns (6) and (9), It goes without saying that the direction of the spiral and the unevenness are opposite.

By forming, for example, a circular pattern (9) having the same area with the same pattern depth, a material flow having the same amount as the material flow amount on the upper surface side of the material (1 ′) is applied to the lower surface side of the material (1 ′). As a result, the resulting fluid bearing is flat with no warp on either side.

The depth of the spiral groove (5) on the punch (2) side is
The depth of the spiral groove required for the flat plate type spiral groove is 1 to 1.5 times, which is suitable in the experiments so far.

If the groove depth of the spiral groove to be formed is 5 μm, the groove depth on the punch (2) side is 5 μm in the case of stainless steel alloy (eg SUS 420J2) material, Al high strength alloy, brass high strength alloy material Was 5 to 8 μm.

Further, when coining, the molding accuracy was improved by applying the lubricant containing the wear resistant particles to the surface of the material (1 ').

In particular, the effect was remarkable with the lubricant containing silicon particles.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, there is an effect that a flat plate type thrust spiral groove bearing having no warp can be stably obtained at low cost with high accuracy.

[Brief description of drawings]

FIG. 1 is a schematic view showing a processing method by a closed coining method showing an embodiment according to the present invention. FIG. 2 is a view showing a flat plate type thrust spiral groove bearing formed by a closed coining method. FIG. 3 is a graph showing an example of analyzing the relationship between the spiral groove depth and the axial rigidity. In the figure, (1) is a flat plate type spiral groove bearing,
(2) is the upper punch, (3) is the die, (4) is the lower punch,
(5) is a spiral groove pattern, (7) is a lubricant, and (8) is the same area pattern. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (5)

[Claims] 1. A method of manufacturing a flat plate type spiral groove bearing for a thrust dynamic pressure fluid bearing, wherein an upper punch having a spiral groove pattern formed on a lower end surface thereof and a lower punch facing the upper punch are used. A pattern having the same area as the spiral groove pattern is formed on the upper end surface of the flat groove, and the spiral groove pattern is formed on the bearing surface side of the flat plate by the relative movement of the upper punch and the lower punch, and the non-bearing surface. A method for manufacturing a hydrodynamic bearing, characterized in that a pattern having the same area as the spiral groove pattern is formed on the side as well. 2. The group depth of the upper and lower punches is 1 to 1.5 times the depth of the spiral groove groove of the flat plate type spiral groove bearing.
A method for manufacturing a fluid bearing according to item. 3. The method for producing a hydrodynamic bearing according to claim 1, wherein the wear-resistant particles are mixed in the lubricant during coining. 4. The hydrodynamic bearing manufacturing method according to claim 1, wherein the lubricant is a lubricant containing silicon-based particles. 5. A flat plate type spiral groove bearing for a thrust hydrodynamic bearing characterized in that a spiral groove pattern is formed on one surface of a flat plate, and a pattern having the same area as the spiral groove pattern is formed on the other surface.