JPS6358282B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support member for a groove bearing and a method for molding the same.

Conventionally, groove bearings (hereinafter referred to as SGBs) have been used in vertical high-speed rotating machines and small precision spindles for audio equipment, etc., due to their low vibration and rotational unevenness. It requires several processing steps and precision, and is difficult to manufacture, resulting in high costs, and despite its excellent properties, its range of use is limited.

Figure 1 shows a conventional spherical SGB.
a is a support member, 11a is a bearing surface, 12a is an outer peripheral surface, 2a is a spiral groove, 3a is a convex spherical surface, and 4a is a shaft. The bearing member 1a is generally made of a copper alloy material, and its parts are machined by turning and grinding, but in particular the bearing surface 11a is a sliding bearing surface that faces and cooperates with the convex spherical surface 3a of the mating member. Therefore, in addition to turning and grinding, processing such as wrapping is required.Furthermore, in order to assemble the bearing correctly, the bearing surface 11a and the outer circumferential surface 12 must be
It is necessary to precisely align the axis with the bearing surface 11a, and the outer circumferential surface 12a is finished with the axis of the bearing surface 11a as a reference. Further, the spiral groove 2a is generally formed into a convex spherical surface 3a as shown in Fig. 1, and is processed one by one for each bearing by a processing method that includes complicated steps such as photo etching. Therefore, the bearing requires a lot of processing time and is extremely expensive in terms of cost.

The present invention aims to facilitate the processing of these conventional bearing members and to obtain a bearing member with excellent vibration damping properties. Pressing is performed using metal with a rational combination of molds and processing temperature settings, thereby simultaneously forming the bearing surface and the outer circumferential surface of the support member with high precision. Moreover, it provides a low-cost support member that requires fewer processing steps.

Next, the supporting member according to the present invention and the method for molding the same will be explained using an embodiment shown in FIGS. 2 to 4. FIG. 2 shows the completed shape of the supporting member according to the present invention, and 1 is the supporting member. , 11 is the bearing surface, 1
2 is an outer peripheral surface, and 2 is a spiral groove. In this case, as in the conventional example, the axes of the bearing surface 11 and the outer circumferential surface 12 are formed to precisely coincide with each other.
Furthermore, when forming the support member 1, Zn-22 is added to the material.
%Al alloy or A1 as the main component with a trace amount of Cu
A cylindrical shape having approximately the same volume as the completed shape shown in FIG. 2 and the shape shown in FIG. It is formed as an intermediate material, and then press working is performed after adjusting the temperature of this intermediate material and the mold to the conditions described below.

FIG. 4 shows the relationship between the press-molded support member 1 and the mold, where 21 is a protrusion of the spherical mold 51 for forming the spiral groove 2, and 5 is a projection for forming the bearing surface 11. This is a die in which a spherical mold 51, an annular mold 52 for forming a flat surface, and an outer cylindrical mold 53 for forming an outer circumferential surface 12 are each integrally fixed by shrink fitting or the like.

The die 5 is fixed to the press by mounting members such as a guide 7 and a receiving part 8 fixed to the table of the press. Further, a punch 9 is attached to a position facing the die 5 so as to be slidable up and down, and a space formed by the die 5 and the punch 9 determines the completed shape of the support member 1. 54.

As mentioned above, the intermediate material 1 is passed through the molding section 54 of the die.
Then, when the punch 9 descends toward the die side, the intermediate member 1 is sealed in the molded part 54 and press-worked as shown in FIG. 12, shapes such as the spiral groove 2 and the flat surface are molded at the same time.

Furthermore, when the punch 9 rises after the completion of forming,
Knock-out pins 6 inserted into several knock-pin holes 521 provided in the annular mold 52 rise, push up the molded support member 1, and take it out from the molding part 54 of the die. .

The temperature of the intermediate material 1 during press working is maintained within a range of ±5°C with respect to the temperature set within the range of 180°C to 270°C.
The temperature of the molds such as die 5 and punch 9 are set respectively, but in this case, if the temperature is below 175℃, the material has high deformation resistance, so a sharp shape cannot be obtained after molding, and if the temperature is below 275℃, If the temperature exceeds the temperature, the superplastic properties will be lost as the temperature exceeds the reciprocal transformation temperature.Furthermore, if the temperature changes within this temperature range by more than ±5℃, the dimensions and shape after molding will become irregular. It is not very desirable for use if it is pressed as it is.

Furthermore, when taking out the molded support member 1 from the mold after press working, the temperature is lowered to 170°C or less, but in this case too, if the temperature is high, the support member 1 is diced with the knockout pin 6. It is easy to deform when taken out from the molding section 54, and in order to ensure final accuracy, it is necessary to
It is necessary to have a range of 10℃. According to the results of experiments under these conditions, the coaxiality between the bearing surface 11 and the outer circumferential surface 12 of the support member is formed within a range of ±5 μm, and sufficient usable accuracy is obtained with the shape and dimensions only by press processing. I was able to do that. Therefore, most of the shape of the support member 1 can be completed by press working, with the exception of some post-processing such as deburring after press working. In this way, fine-grained superplastic metals can transfer the mold surface extremely faithfully, so by giving the bearing surface forming part of the mold a good surface finish by lapping, etc., the wrapped mold surface can be A bearing surface equivalent to that can be obtained. In addition, as in the above-mentioned embodiment,
When the bearing surface 11 has the spiral groove 2, the protrusion 21 is formed on the spherical mold 51 by a method applying photoelectroforming (a combination of photoresist and plating).
It can be easily press-molded.

Furthermore, FIGS. 5 to 7 show other embodiments of the present invention, in which FIG.
SGB Supporting Member, FIGS. 6 and 7 respectively show the thrust SGB bearing member, and both are molded using the same materials, temperature conditions, and press working as described above.

As described above, since the bearing member 1 according to the present invention uses a fine grained superplastic metal material as a material, the bearing surface 11 having the groove 2 and the outer circumferential surface 1
2 etc. can be press-molded at the same time.

Furthermore, another reason for using the above-mentioned fine-grained superplastic metal material is its excellent vibration damping properties, and experimental results show that the bearing member according to the present invention can be machined with conventional BeCu material (beryllium copper alloy). It has been confirmed that the runout accuracy is superior to that of machined bearing members. Figure 8 shows the structure of the experimental apparatus, where 1b and 1 are supporting members for the spherical SGB used in the experiment, 1b is the conventional one, and 1 is the one according to the present invention, which is used as a thrust receiver for the shaft 2b. The radial bearing is a dynamic pressure type consisting of a herringbone groove 21b provided on the outer periphery of the shaft 2b and an inner surface 31b of the outer cylinder 3b, and is all supported by a bearing 22b. Axial runout at a point
The accuracy of the radial runout Vr at point Va and point B was measured.

Figure 9 shows the relationship between the rotational speed (rpm) and the shaft runout (Va and Vr) when a support member 1b formed by machining a conventional BeCu material is incorporated into the experimental apparatus. be. Furthermore, in Figure 10,
A rotation test was conducted using the support member 1 according to the present invention in place of the above-mentioned support member 1b, and other parts were kept under the same experimental conditions as in FIG. 9, and the results are shown. In this case, the shape and size accuracy of the bearing surface of the support member is adjusted to within ±1 μm.

As is clear from the results in Figures 9 and 10,
A large difference in runout accuracy appears in the region of 3000 rpm or higher, where the groove bearing operates most effectively, indicating that the bearing member 1 of the present invention has excellent vibration damping (or vibration absorbing) properties in the above rotation region. ing. Therefore, the support member of the present invention is particularly effective for precision rotation in high-speed ranges, and is also useful for preventing whirl (abnormal shaft whirling phenomenon).

In addition, in the case of a support member having a spherical or conical bearing surface 11, the mold used for press working is integrally provided with surfaces facing both the bearing surface 11 and the outer circumferential surface 12 of the support member. dice 5 and
Since it is constituted by a punch 9, the coaxiality between the bearing surface 11 and the outer peripheral surface 12 can be formed with high precision by setting the temperature of the support member 1 in accordance with the processing conditions. Can be done.

Furthermore, when forming the groove 2 on the bearing surface 11, the protrusion 2 is formed by a processing method such as photoelectroforming of the mold 51.
Since it can be press-molded using 1, it is extremely easy to manufacture. In the embodiment, a groove is formed on the bearing surface 11 of the support member, but it is also possible to provide the groove on the surface on the side of the mating member and use the bearing surface 11 without a groove.

Further, in the embodiment, the die 5 has a structure in which three types of molds are combined, but it may be formed as a single mold.

According to the support member of the groove bearing and its molding method of the present invention, the support member 1 has excellent vibration damping properties and can be mass-produced with high precision by press working, so the processing steps are omitted compared to the conventional method, and the cost is reduced. can be significantly reduced.

Further, there is an effect that the coaxiality between the bearing surface 11 and the outer circumferential surface 12 is good.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional spherical spiral groove bearing, and FIGS. 2 to 4 are views showing an embodiment of the support member and molding method of the groove bearing according to the present invention. 3 is a perspective view showing the intermediate material shape of the support member, FIG. 4 is a sectional view showing press forming of the support member, and FIGS. 5 to 7 show other embodiments of the present invention. Figure 5 is a cross-sectional view showing the support member of a conical groove bearing, Figure 6 is a plan view showing the support member of a planar thrust groove bearing, and Figure 7 is a cross-sectional view of the support member shown in Figure 6. 8 is a sectional view of an experimental device for measuring the runout accuracy of a bearing, FIG. 9 is a graph of runout accuracy using the conventional support member for the device shown in FIG. 8, and FIG. 8 is a graph of runout accuracy when the support member according to the present invention is used in the device shown in FIG. 8. In the symbols of the embodiment, 1 is a support member, 11 is a bearing surface, 12 is an outer peripheral surface, 2 is a groove, 5 is a die,
6 is a knockout pin, and 9 is a punch.

Claims (1)

[Scope of Claims] 1. A support member for a groove bearing, which is made of a fine-grained superplastic metal material and characterized in that a bearing surface provided at the shaft center and an outer circumferential surface are formed by press working. 2. The support member for a groove bearing according to claim 1, wherein a groove is formed on the bearing surface. 3 A member made of a fine-grained superplastic metal material is used as an intermediate material, and the intermediate material is pressed at a processing temperature within the range of 175°C to 275°C to form a bearing surface and an outer peripheral surface provided at the shaft center. 1. A method for molding a support member for a groove bearing, the method comprising: molding a support member in which the molded support member is molded, and removing the molded support member from the mold after the temperature reaches 170° C. or lower.