JP3507666B2 - Manufacturing method of sintered oil-impregnated bearing with internal groove - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a sintered oil-impregnated bearing having an annular or spiral groove in the sliding direction of the inner diameter surface of the sliding bearing.

[0002]

2. Description of the Related Art In order to obtain an oil sump effect during sliding of a rotary member, a groove is formed annularly or spirally in the sliding direction of a sliding surface of a plain bearing element. Some sintered bearings have grooves that serve as oil reservoirs and have sliding surfaces at both ends of the bearing inner diameter and bulges at the middle portion of the inner diameter. Method of swelling the outer diameter side, or sizing the sintered material in which one end side of the inner diameter is made small and the other end side is made large, etc. Produced by. For large diameter bearings, grooves can be made with a cutting tool.

[0003]

If the groove on the inner diameter surface is composed of a plurality of rings or in the shape of a spiral, it is impossible to remove the molded body from the mold by the ordinary powder compacting method, so molding is possible. Have difficulty. An object of the present invention is to manufacture such a grooved bearing by means of ordinary powder compacting and sizing using a mold.

[0004]

In order to solve the above problems, in the method of the present invention, the inner diameter surface 2 of the bearing hole is provided with a plurality of steps 7a from one end side to the other end side so that the inner diameter is gradually increased. The outer diameter surface 4 is formed as a taper surface having a small diameter on the small inner diameter side and a large diameter on the large inner diameter side, or a small inner diameter is provided by a step 8 provided at a position corresponding to the middle of the adjacent step 7a of the inner diameter surface. Side of the sintered material is deformed in a mold with a cylindrical cavity, and the large diameter part of the sintered material is reduced in diameter. It is characterized by that. Further, in another method of the present invention, in the sintering material, the step 7a of the inner diameter is formed into a spiral shape and the outer diameter surface 4 is tapered or the step 8 is formed.
It is characterized by having a spiral shape having.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The manufacturing method of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a bearing manufactured by the method of the present invention. The bearing 1 has a groove 3 on its inner diameter surface. FIG. 1A shows an example of a bearing having three annular grooves, and FIG. 1B shows an example having a continuous spiral groove.

The sintering material used for manufacturing such a bearing will be described below. FIG. 2 is a vertical cross-sectional view of the sintered material. In the sintered material shown in FIG. 2 (a), the inner diameter surface 2 has a small diameter in the lower part of the drawing, and the step 7a increases the diameter in four steps toward a large diameter. Is formed in. The step 7a can be changed depending on the size of the bearing, but it is from several μm to several hundred μm.
Is. The outer diameter surface 4 is formed as a taper surface having a small diameter on the lower side. From the standpoint of workability in die powder molding, it is desirable to provide some flat portions at both ends. In the structure shown in FIG. 2B, the shape of the inner diameter surface 2 is the same as that described above, but the outer diameter surface 4 is formed by the step 8 so that the lower side of the figure is small and the diameter is increased in four steps toward the large diameter. The step 8 is provided at a position corresponding to the middle of the adjacent steps 7a having the inner diameter. The steps shown in FIGS. 2A and 2B are formed in an annular shape, but the steps may be spiral.

The sintered materials having these shapes can be molded by powder compaction. The die hole of the die has a shape having a taper, a step having a different diameter, or a spiral step, and the core has an annular step 7b as shown in FIG. 4 (a), or the core shown in FIG. 4 (b). As described above, the step 7b having a spiral shape is used. Further, the molding die has a rod-shaped lower core which is supported by a lower punch and a spring in a die hole and is reciprocally movable in the axial direction, and the inner hole of the upper punch has the shape shown in FIG. 4 (a) or (b). As shown, an upper core 9 is used.
In powder molding, after filling the die cavity with powder by a usual method, the upper core 9 is lowered and the lower core is pushed down, the upper core 9 is inserted into the powder, and compression molding is performed with the upper and lower punches.

FIG. 2 (a) or (b) obtained by sintering
The bearing material shown in (1) is sized as in the case of a normal cylindrical bearing. In the sizing die, the diameter of the die hole is almost the same as the small diameter portion of the material outer diameter, and the outer diameter of the core is almost the same as the small diameter portion of the material inner diameter. Depending on the bearing material and the wall thickness and size, the groove may be formed better by making the size of the mold slightly larger or smaller than the material size.

FIG. 3 is a schematic vertical sectional view for explaining the plastic deformation of the bearing material due to sizing. Figure 1
A case of forming the annular groove shown in (a) and plastic deformation of only in the direction perpendicular to the axis will be described as an aspect of groove formation. FIG. 3 (a) shows a case where the material shown in FIG. 2 (b) is subjected to sizing, and the sintered material obtained by powder compacting is formed by the core portion 5 and the die whose shape does not change before and after sizing. The reduced-diameter portion 6a is pushed into the shaft core side, and the expanded portion 6b is pushed out in the axial direction by the reduced-diameter portion 6a. The groove 3 is formed by forming the bulging portion 6b. This figure is a schematic diagram, and in reality it is not plastically deformed into such a clear shape, but in a substantially similar form the sliding surface and the groove 3
Is formed. By adjusting the diameter of the reduced diameter portion 6a and the core,
It is also possible to make the densities above and below the bearing the same or to form one side densely. FIG. 3B shows the case of the material shown in FIG. 2A, and the groove 3 is formed in a vertically asymmetrical sectional shape.

[0010]

As described above, according to the manufacturing method of the present invention, by the ordinary die molding and sizing,
Since the groove can be formed on the inner diameter surface by utilizing the plastic deformation, it becomes possible to provide the bearing having a new function at a low cost.

[Brief description of drawings]

1 (a) and 1 (b) are vertical cross-sectional views of an example of a bearing manufactured by the method of the present invention.

2 (a) and 2 (b) are vertical cross-sectional views of an example of a sintered material used in the method of the present invention.

FIG. 3 is a schematic vertical sectional view for explaining a state of plastic deformation due to sizing. FIG. 3A shows the case where the sintering material shown in FIG. 2B is used, and FIG. 3B shows the case where the sintering material shown in FIG. 2A is used.

FIG. 4 (a) and FIG. 4 (b) are side views of a powder compacting core for molding a sintered material.

[Explanation of symbols]

1 bearing 2 Inner surface 3 grooves 4 Outer surface 5 core 6a reduced diameter part 6b bulge 7a Step (inner diameter surface) 7b Step (core) 8 steps (outer diameter surface) 9 cores

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Claims (2)

(57) [Claims] 1. An inner diameter surface 2 of a bearing hole is provided with a plurality of steps 7a from one end side to the other end side so that the inner diameter is gradually increased, and the outer diameter surface 4 has a smaller inner diameter side and a larger inner diameter side. Sintering formed on the taper surface having a diameter or formed so that the outer diameter is gradually increased from the small inner diameter side to the large inner diameter side by the step 8 provided at the position corresponding to the middle of the adjacent step 7a on the inner diameter surface. Manufacture of a sintered oil-impregnated bearing with an inner diameter groove, characterized in that the sintered material is press-fitted into a mold having a cylindrical cavity to be deformed, and a large diameter portion of the outer diameter of the sintered material is reduced. Law. 2. A spiral step 7a whose inner diameter increases from one end side to the other end side is formed on the inner diameter surface 2 of the bearing hole, and the outer diameter surface 4 has a small inner diameter side and a large inner diameter side. Steps 7 formed on a large-diameter tapered surface or adjacent to the inner diameter surface
Using a sintered material formed into a spiral surface whose outer diameter increases from the small inner diameter side to the large inner diameter side by a step 8 provided at a position corresponding to the middle of a, the sintered material is a metal having a cylindrical cavity. A method for manufacturing a sintered oil-impregnated bearing with an inner diameter groove, which comprises press-fitting into a mold to deform it, and reducing the large diameter portion of the outer diameter of the sintered material.