JPH0818190B2 - Bearing structure manufacturing method - Google Patents

Description

The present invention relates to a method of manufacturing a bearing structure including a pair of half bearing members. Specifically, a method of manufacturing a bearing structure capable of processing a bearing hole with a high roundness by boring and then honing the bearing hole in a state where a pair of half bearing members are integrally assembled. It is about.

(Prior Art) As a bearing structure for a shaft that rotates at high speed, one that has conventionally been composed of a pair of half-divided bearing members has been generally adopted, and in order to smoothly lubricate the shaft and prevent seizure, the bearing structure It is required that the bearing hole portion be formed with high roundness. Therefore, the bearing structure is formed by integrally assembling the bearing members, boring a bearing hole formed by the bearing members with a boring machine, and then honing the hole with a honing machine. ing. Since each of the bearing members is integrally assembled, the hole is machined with high circularity, but when assembled on the shaft, the circularity during machining is not maintained and is extremely small. However, it is deformed into an oval shape, which causes a shaft and pole contact, which may result in insufficient lubrication.

For example, a manufacturing method for manufacturing the bearing structure of the large end portion of the connecting rod of the engine shown in FIG. 3 will be described.

The connecting rod is provided with a small end bearing structure 2 connected to a piston pin (not shown) at one end of a trunk portion 1 and a large end bearing connected to a crank pin (not shown) at the other end. A structure 3 is provided. The bearing structure 2 at the small end is formed with a bearing hole h, and the cylindrical bearing metal 4 is press-fitted and mounted in the bearing hole h when connecting to the piston pin. Large end bearing structure 3
Is a bearing cap 6 having a bearing main body 5 having a half-divided bearing hole portion Ha and a half-divided bearing hole portion Hb integrally connected to the bearing main body 5 by two connecting rod bolts 7.
When connecting to the crank pin, the pair of half bearing metal pieces 8 are mounted in the bearing hole portion H formed by the bearing body 5 and the bearing cap 6.

The connecting rod shown in FIG. 3 is configured as described above, and the large-end bearing structure 3 is manufactured according to the machining-assembly process of FIG. 5 and assembled to the crankpin.

That is, in the processing step, the bearing body 5 and the bearing cap 6 are separately broached into the half-divided bearing hole portions Ha and Hb. First, as shown in FIG. Are assembled together with connecting rod bolt 7. At that time, the bearing hole portions Ha and Hb form an integral bearing hole portion H. After that, the bearing hole H is bored by a boring machine and both side surfaces of the bearing structure 3 are cut. After the cutting process is completed, the bearing hole portion H is subjected to a honing process with a honing machine to finish it to a predetermined size and surface accuracy.

After finishing the above processing steps, the assembly process begins,
First, the connecting rod bolt 7 is loosened, and the bearing cap 6 is removed from the bearing body 5. Next, the bearing metal 8 is attached to each of the bearing body 5 and the bearing cap 6. After a while
Attach to the crank pin.

By the way, the crankpin is formed with a high roundness, and the bearing structure 3 at the large end is also formed with the bearing hole H having a high roundness, but the lubrication between them is not always smooth. However, there is a problem that the shaft and the bearing metal 8 are unevenly worn, and in some cases, seizure occurs.

The above-mentioned problem is caused when the bearing hole H of the large-end bearing structure 3 is deformed into an oval shape when the bearing cap 6 is removed from the bearing body 5. That is, the bearing hole H of the bearing structure 3 at the large end is formed in a circular shape H _{11 as} shown in FIG. 6 (A) at the end of the boring process of the bearing hole in the processing step shown in FIG. At the end of the honing process, as shown in FIG. 6 (B), a circular shape with a high circularity H ₃₁ is formed. After the honing process is completed, the bearing cap 6 is once removed and reassembled. As shown in FIG. 6 (C), it may be deformed to an oval shape H ₄₁ although it is very slight, and it is not always always formed with a high roundness. In particular, although not clearly shown in the drawing, the bearing cap 6 is often deformed to a greater extent than the bearing main body 5 although it is slight.

As described above, according to the conventional manufacturing method, even if the roundness is high at the end of processing, it is possible to ensure that the bearing has a high roundness when assembled on the shaft that is actually required. There is a problem that the hole may not be maintained.

(Object of the invention) The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to ensure that a bearing hole portion having a high roundness is formed without causing deformation even after machining. It is to provide a method of manufacturing a bearing structure that can be formed.

(Structure of the Invention) As a result of studies conducted by the present inventor to achieve the above object, it is said that the cause of the deformation of the bearing hole portion after the honing process is that residual stress is generated in the bearing structure at the end of the honing process. It became clear.

For example, in the method of manufacturing the bearing structure 3 at the large end portion of the connecting rod shown in FIG. 5, when the bearing hole H of the bearing structure 3 at the large end portion is bored, a large cutting allowance is taken. ing. Therefore, a high cutting pressure acts and a large amount of heat is generated, and a large processing stress and a thermal stress are generated in the bearing body 5 and the bearing cap 6. However, until the end of honing, the bearing body 5
Since the bearing cap 6 and the bearing cap 6 are firmly connected to each other by the connecting rod bolt 7, the above-mentioned stresses exist as residual stresses in the bearing body 5 and the bearing cap 6 at the end of the honing process. Therefore, loosen the connecting rod bolt 7 when assembling to the crank pin,
When the bearing cap 6 is removed, the bearing body 5 and the bearing cap 6 are deformed in the direction in which residual stress is released, that is, outward, and the bearing hole portion H formed by both is shown in FIG. 6 (C).
It will be transformed into an oval H _{41 as} shown in. In particular, the bearing cap 6 has a rigidity lower than that of the bearing body 5, so that the bearing cap 6 is slightly deformed.

On the other hand, when honing, the grinding allowance is small and the grinding feed amount is also small, so that machining stress and thermal stress are hardly generated, and residual stress that affects the deformation is not generated. Not not.

From the above, after the residual stress generated by the boring process of the bearing hole H is temporarily released, the honing process is performed, so that the bearing body 5 and the bearing cap 6 can be removed even when the bearing cap 6 is removed at the end of the honing process. The bearing hole portion H formed by and can maintain high roundness at the end of honing.
It became clear.

The method for manufacturing a bearing structure of the present invention has been completed based on the above matters, and its structural feature is that a pair of half bearing members are integrally assembled and a bearing hole is bored. The purpose is to manufacture a bearing structure by once disassembling the two and then reassembling the two, and honing the bearing hole.

(Example) An example of the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a process diagram for explaining a machining-assembly process of the bearing structure of the large end portion in the connecting rod shown in FIGS. 3 and 4, and FIG. 2 is each machining process shown in FIG. FIG. 3 is an explanatory view schematically showing the relationship between the bearing hole shape of the bearing structure of the large end portion in FIG.

When manufacturing the bearing structure 3 of the large end portion of the connecting rod shown in FIG. 3, the bearing body 5 and the bearing cap 6 obtained by broaching the bearing holes Ha and Hb in the half-divided form as in the conventional case are used. As shown in the machining-assembly process of FIG. 1, the connecting rod bolts 7 are integrally assembled, and the bearing hole H is bored by an unillustrated boring machine. At that time, the bored bearing hole H is
As shown in FIG. 3A, it is formed in a circular shape H ₁ .

After that, both sides are cut and connecting rod bolt 7
Is loosened and the bearing cap 6 is removed from the bearing body 5. Then, the bearing cap 6 is attached again. At that time, the bearing hole H has a slightly oval shape as shown in FIG. 2 (B).
It is transformed into H ₂ . Although not explicitly shown in the figure, the bearing cap 6 is actually slightly deformed more than the bearing main body 5 although it is slightly.

Next, the bearing hole portion H is honed by a conventionally known honing machine to be machined to a predetermined size and surface accuracy. Therefore, the bearing hole H of the oval shape H ₂ is corrected,
As shown by the solid line in FIG. 2 (C), a circle H _{3 with} a high roundness is used.
Formed. Bearing cap 6 after honing
The bearing body 5 by loosening the connecting rod bolt 7.
Then, the pair of half bearing metal pieces 8 are interposed and assembled to the crank pin. At that time, the bearing main body 5 was tested.
When the bearing cap 6 was attached to the bearing cap 6, the bearing hole portion H was maintained in the circular shape H ₃ having the same high roundness as at the end of the honing as shown in FIG. 2 (D).

As described above, the bearing hole portion H of the bearing structure 3 at the large end portion
Is released by loosening the connecting rod bolt 7 and removing the bearing cap 6, the residual stress due to the machining stress and the thermal stress generated by the boring process is released. As shown in the figure, the shape is slightly deformed into an oval shape H ₂ , but the shape is modified by a honing process into a circular shape H ₃ having a high roundness as shown in FIG. 2 (C). At the end of the honing process, the working stress and the thermal stress generated by the boring process have already been removed, the working stress and the thermal stress caused by the honing process are hardly generated, and the residual stress is almost generated in the bearing structure 3. Since this is not done, when the bearing cap 6 is removed, the bearing structure 3 is not deformed as in the conventional case. Therefore, when the bearing structure is assembled to the crankpin, the bearing structure can be assembled in a state of high roundness and does not have a pole contact with the crankpin as in the conventional case, and can perform smooth lubrication. Could be formed.

Although the present embodiment has been described by applying the present invention to the manufacture of the bearing structure of the large end portion of the connecting rod of the engine, the main bearings and the main bearings for the plurality of cam shafts provided in the cylinder head portion of the engine are described. It goes without saying that the present invention can be applied to the case where a bearing structure including a bearing cap and a bearing structure for a crankshaft of a cylinder block are manufactured at the same time.

(Effects of the Invention) The method for manufacturing a bearing structure according to the present invention is such that the pair of half bearing members are integrally assembled, and after boring, the residual stress generated during boring is released by temporarily disassembling the two members. Can be eliminated,
When assembling to the shaft after finishing honing, each bearing member will not be deformed as in the conventional method, and surely manufacture a bearing structure having a bearing hole with high roundness similar to that at the end of machining. You can

[Brief description of drawings]

FIG. 1 is an explanatory view of the working-assembly process of the embodiment of the present invention. FIG. 2 is an explanatory view showing the shape of the bearing hole and the relationship of each shape corresponding to the process shown in FIG. 1, (A) at the end of boring, (B) at the time of reassembling the bearing cap,
(C) shows the shape at the end of honing, and (D) shows the shape at the time of assembly in the assembly process. FIG. 3 is an assembly view of a conventionally known connecting rod, FIG. 4 is a front view of the connecting rod shown in FIG. 3 during processing, and FIG. 5 is an explanatory view of a processing-assembly process of a conventional example. FIG. 6 is an explanatory view showing the shape of the bearing hole and the relationship between the shapes, corresponding to the step shown in FIG.
(B) shows the shape at the end of honing, and (C) shows the shape at the time of assembly in the assembly process. 1 ... Trunk, 2 ... Small end bearing structure, 3 ... Large end bearing structure, 5 ... Bearing body, 6 ... Bearing cap,
7 ... Connecting bolts, Ha, Hb ... Half-divided bearing hole, H ... Bearing hole.

Claims (1)

[Claims] 1. A method of manufacturing a bearing structure comprising a pair of half-divided bearing members, wherein the bearing members are integrally assembled, the bearing hole is bored, the assembly is temporarily canceled, and then the two are assembled again. A method of manufacturing a bearing structure, comprising honing the bearing hole.