JPS5834684B2 - Multi-arc sliding bearing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sliding bearing device having a polycylindrical arc cross section.

The concept of a polycylindrical plain bearing can be explained using Figure 1.
This figure shows a three-arc shaped belly bearing, and shows a state in which a shaft 2 is inserted into a bearing 1 consisting of three arcs.

Bearing 1 is in the shape of a three-circle arc, so bearing 1 and shaft 2
Three minimum gap portions C1 and three maximum gap portions C2 are formed between them.

A polygonal arc-shaped plain bearing having the above-mentioned shape has excellent performance that cannot be possessed by a normal plain bearing having a circular cross section.

In general, it is better for a sliding bearing to have a small clearance with the shaft in order to prevent vibrations generated between the bearing and the shaft, and on the other hand, it is preferable that the clearance be large in order to prevent seizure and reduce friction loss.

Therefore, in a plain bearing having a circular cross section, the above two requirements are clearly contradictory.

However, in such a multicircular arc-shaped sliding bearing, the minimum gap portion C1 can reduce the vibration of the axis of the shaft 2 and prevent the generation of hammering noise, and at the same time, the maximum gap portion C2 can increase the amount of lubricating oil. This has the advantage of being able to prevent seizure between the bearing 1 and the shaft 2 and further reduce friction loss.

As mentioned above, polycylindrical arc-shaped plain bearings have extremely superior features compared to circular plain bearings, but the main reason why polycylindrical arc-shaped plain bearings are rarely used in practice is This resulted in the difficulty of molding it.

The present invention was developed as a result of efforts to obtain a polygonal arc-shaped sliding bearing that is easy to manufacture. This was completed based on the knowledge that the radius of curvature of the thin portion of the bushing becomes smaller than that of other portions due to the pressure applied when the bushing is press-fitted.

In other words, the polycylindrical arc-shaped plain bearing according to the present invention includes a cylindrical housing material provided with a thin-walled portion parallel to its axis, and a cylindrical bushing tightly press-fitted into the inner circumferential portion of the housing material. It is characterized by integrating these two parts and forming the bushing and the housing material into a polygonal arc of the same shape.

The present invention will be explained below with reference to illustrated embodiments. FIG. 2A shows an example of the shape of the housing, and FIG. 2B shows an example of the shape of the bushing 4. The housing material 3 is formed into a uniform cylindrical shape, and a groove 3a is formed on the outer surface of the housing material 3, parallel to the axis and extending over the entire length of the housing material 3.

In other words, three arc-shaped thick parts 3b are connected by a thin part 3c having low rigidity.

Next, when a cylindrical bushing 4 having an outer diameter slightly larger than the inner diameter is press-fitted into the inner circumference of the housing material 3, the thinner part 3c of the housing material 3 has a lower rigidity than the thicker inner part 3b. Since the three thick portions 3b are small, the three thick portions 3b bend and deform the thin portions 3c at both ends to reduce their radius of curvature and increase the radius of curvature of the thick inner portion 3b itself.

That is, the housing material 3 together with the bushing 4 has a multi-arc cross section, resulting in the sliding bearing 6 and the housing 5 having a shape as shown in FIG.

If the shaft 7 is inserted into this polycylindrical plain bearing 6,
A minimum gap portion C1 is formed near the thick portion 5b, and a maximum gap portion C2 is formed near the thin portion 5c.

The polygonal arc-shaped plain bearing 6 having the above configuration has a shaft 7
Since the shaft 7 has a minimal gap C1 between the
It is possible to suppress the vibration of the axis caused by the rotation of the drum and prevent the hammering sound.

Furthermore, since this sliding bearing 6 has an extremely thick gap section C2 between it and the shaft 7, the amount of lubricating oil inserted into this section can be increased, which improves the cooling effect and prevents seizure. It can be prevented.

FIG. 4 shows an example of the shape of the polygonal arc-shaped plain bearing formed as described above.

This shows the result of measurement of the inner circumference of the bearing by the inventors, where a is the shape of the inner circumference of the bearing, and b is a perfect circle inscribed in a.

However, the housing has an outer diameter of 34 mm and an inner diameter of 25.01 g.
m, with a groove of 5 mm wide and 2.5 mm deep on its outer circumference.
° Three lines were carved at equal intervals.

The bushing press-fitted into the housing above has an outer diameter of 25.07m.
m, and the inner diameter is 22 mm.

After this press-fitting, the deviation d of the portion of the inner circumference a of the bushing corresponding to the back groove portion 3a from a perfect circle was 25 μm.

In addition, e is a joint part when the said bush is formed into a cylinder, and it is preferable to set it in the part corresponding to the groove part 3a.

The number of grooves 3a carved in the housing material 3 may be appropriately selected depending on the application of the plain bearing.If two or four grooves are set, the number of grooves 3a carved in the housing material 3 can be set as many as shown in FIGS. 5 and 6, respectively. A circular arc-shaped plain bearing device is formed.

Further, it goes without saying that the effects of the present invention can be achieved even if the cross-sectional shape of the groove portion 3a is a square shape, a U shape, or another shape.

Furthermore, the thin wall portion 3c of the housing may be formed by not only forming the groove portion 3a but also by drilling a hole parallel to the axis in the cylindrical portion.

As described above, according to the present invention, a polycylindrical arc-shaped plain bearing that can prevent both vibration and seizure can be obtained very easily, and in particular, this housing material can be applied to a cylindrical housing material having a thin wall portion in the axial direction. Since the bushing having an outer diameter slightly larger than the inner diameter is tightly press-fitted to integrate the two, the housing material and the bushing are simultaneously deformed and connected to each other, and the bushing is attached to the housing material over the entire circumference. This has the effect of making it possible to construct a solid polygonal plain bearing device backed by

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of a polycylindrical arc-shaped plain bearing, Fig. 2 A and B are sectional views showing examples of the shapes of the housing and bushing before press-fitting, respectively, and Fig. 3 is a press-fitted polycylindrical arc-shaped plain bearing. FIG. 4 is a cross-sectional view showing an exaggerated example of one embodiment; FIG. 4 is a graph showing the results of measuring an example of the amount of deviation from a perfect circle of the polygonal arc-shaped plain bearing according to the present invention; FIGS. Each figure shows 2
FIG. 3 is a cross-sectional view showing a circular arc type and a four circular arc type sliding bearing. 3... Housing material, 3c... Thin wall portion, 4... Bush, 6... Polycylindrical arc sliding bearing.

Claims (1)

[Claims] 1. A cylindrical housing material having a thin wall portion parallel to the axis, and a cylindrical bushing having an outer diameter slightly larger than the inner diameter of this housing material, and this bushing is tightly press-fitted into the housing material. A polycylindrical sliding bearing device in which these two are integrated and the bushing and housing material are formed into a polycylindrical arc of the same shape.