JPH07101053B2 - Selective mating method for plain bearings - Google Patents

Description

[Technical Field] The present invention relates to a selective fitting method for selectively fitting a plain bearing (half-divided type bearing) and a housing accommodating and holding the flat bearing according to variations in the dimensions of both. Regarding

“Prior Art and Its Problems” This type of plain bearing (sliding bearing) is widely used for the crankshaft portion of an engine and others. FIG. 3 is a conceptual diagram showing the assembled state. The semi-cylindrical plain bearings 11, 11 that rotatably support the shaft 10 are housed in the housings 12, 12, and the fixing bolts 13, 13 are tightened. By the housing
Fixed within 12. An oil clearance is set between the shaft 10 and the plain bearing 11, and lubricating oil intervenes in this clearance. If the oil clearance is too small, lubrication will be insufficient, and if it is too large, a tapping sound will be produced, so it must be maintained in an appropriate range.

By the way, it is relatively easy to control the diameter of the shaft 10 held in the plain bearing 11 in a narrow fixed range, but the side of the plain bearing 11 is not only its own size, but also a housing for fitting and holding it. It is also affected by 12 dimensions, so it is difficult to control the dimensions. Therefore, conventionally, the housing 12 has a diameter of 2
On the other hand, the plain bearing 11 side is also classified into two or more depending on the thickness of the central part of the plain bearing 11 side, and these are selected and fitted so that the oil clearance falls within a certain range. Method is used.

The chart of FIG. 5 shows an example of a conventional selective fitting method. In this example, the standard diameter d of the shaft 10 is 55 mm, and the plain bearing 11
Standard wall thickness t of 2mm, standard inner diameter D of housing 12 is φ59m
In the selective fitting example when m is set, the thickness of the central portion of the plain bearing 11 is measured, and the flat bearing 11 is a ', b',
It is classified into three types, c '. The reason why the wall thickness of the plain bearing 11 is measured at the center is that the wall thickness at the side is set to be slightly smaller than that at the center so as to form an oil relief. On the other hand, the inner diameter of the housing 12 is also measured in the same manner, and this is also classified into three types of A, B and C depending on the size. Then, fit the plain bearing 11 of A'class with the largest wall thickness into the housing 12 of A class with the largest inner diameter, and fit the plain bearing 11 of intermediate b'class into the housing 12 of B class in the middle. , The plain bearing 11 of the smallest c'class is fitted into the housing 12 of the smallest C class. The diameter of the shaft 10 is restricted to a narrow range as shown in the figure.

According to such a selective fitting method, it is possible to suppress the variation in the oil clearance due to the variation in the wall thickness of the plain bearing 11 and the variation in the inner diameter of the housing 12, and to keep this within a certain range. Therefore, the selective fitting method has been widely used in the past.

On the other hand, in order to fit and fix the plain bearing 11 to the housing 12,
Conventionally, it has been performed to provide the plain bearing 11 with a tightening margin called a crush. That is, a crush is a plain bearing
This means the difference between the circumferential length of 11 and the inner circumferential length of the housing 12. The circumferential length on the plain bearing 11 side is naturally slightly longer than that on the housing 12. This circumferential length is actually measured as "foot height". FIG. 4 is a conceptual diagram of the measuring method, in which one end of the plain bearing 11 attached to the gauge block 20 is fixed by abutting against the stopper 21, and the measuring pressure P is applied to the other end of the plain bearing 11, Measure the height H. This H is "foot height", which means that the circumferential length of the plain bearing 11 is indirectly measured.
That is, there is a constant proportional relationship between the circumferential length and this foot height.

This foot height can be set within an error range of about 30 μm. In the conventional selective fitting method described above, regardless of the wall thickness of the plain bearing 11, this is as shown in the chart of FIG. In addition, it is kept within a certain narrow range. However, if the foot height is kept within a certain range regardless of the wall thickness of the plain bearing 11 in this manner, the housing diameter varies, and thus the variation in the amount of crushing increases. There is a problem in that variations and variations in compression stress generated in the plain bearing 11 become large.
Particularly in recent engines, where the rigidity of the housing 12 has been reduced due to the demand for smaller size and lighter weight, the foot height becomes relatively large in relation to the housing diameter, and as a result, the housing 12 side becomes There is a tendency that the rate of extension increases and the oil clearance also increases. When the oil clearance increases, the beating noise of the bearing increases, and the quietness required for the engine is sacrificed.

[Object of the Invention] The present invention provides a selective fitting method for a plain bearing, which is an improvement over the conventional selective fitting method, in which variations in the crash are reduced, and thus the oil clearance can be maintained at a narrower proper value. The purpose is to

[Summary of the Invention] The present invention classifies flat bearings according to the size of the wall thickness, and sets the circumferential length (foot height) of the flat bearing with a large wall thickness to a large value. The length in the direction is also added as one element of the plain bearing classification, and the plain bearings thus classified and the housings classified according to the inner diameter are compared with each other in terms of the wall thickness and the circumferential length of the plain bearing and the housing. It was completed based on the idea of selecting and fitting the inner diameters of the two so that they match the size of the inner diameter.

The selective fitting method of the present invention is a plain bearing classification step of classifying a semi-cylindrical plain bearing into at least two types according to the thickness of the plain bearing; According to the classification of size, a plain bearing that is machined so that the thickness in the circumferential direction is large for thick ones and small for small ones. A machining step; a housing classification step of classifying a housing for holding and holding a plain bearing into at least two types according to its inner diameter; and a plain bearing classified and processed in this manner and a classified housing of a plain bearing. The present invention is characterized by including a selective fitting step of selecting and fitting so that the wall thickness and the length in the circumferential direction and the size of the inner diameter of the housing match.

"Examples of the Invention" The present invention will be described below with reference to illustrated examples. FIG. 1 is a table showing plain bearings 11 classified according to the present invention. The basic numerical values are the same as the conventional classification described in FIG. 5, but in the present invention, the foot height H of the plain bearing 11 is introduced as a new additional classification element of the plain bearing 11. This foot height H
Are the elements described in FIG. 4, and the plain bearing 11 is classified into three types, a, b, and c, by the combination of the foot height H and the central portion wall thickness t.

In this classification, first, the wall thickness of the center part of the actually manufactured plain bearing 11 is measured, and this is classified into three types, a, b, and c, in the order of increasing wall thickness within the allowable range, and then the wall thickness. Large classification a
The plain bearing of No. 1 is also processed so that the foot height H becomes the maximum within the allowable range. Similarly, for the plain bearings 11 of category b with the intermediate thickness, the foot height H is also adjusted to the intermediate region, and for the plain bearings of category c with the smallest thickness,
Processing is performed so that the foot height H is also reduced. It should be noted that
As is clear from FIG. 1, the allowable dimensional difference of the foot height H of each of the classifications a, b, and c is about 30 μm.
This is equal to the allowable dimensional difference of the foot height H in the conventional device of FIG. That is, the present invention is characterized in that the size of the foot height H is changed according to the size of the wall thickness without increasing the processing accuracy itself. It is possible to process the foot height H within this size range with a yield of almost 100%. It does not prevent controlling the foot height H in the narrowest dimension range.

Then, the plain bearing 11 of class a classified as described above is placed in the housing 12 of class A having the largest inner diameter, the plain bearing 11 of class c is placed in the housing 12 of class C having the smallest inner diameter, and plain bearing 11 of class b is provided. Are selected and fitted into the intermediate B-class housings 12, respectively.

According to the above combination, the flat bearing 11 having a large wall thickness and foot height (small) is fitted into the housing 12 having a large inner diameter (small), so that the crash fits within an appropriate range. Clearance is also within the proper range. Also, the compressive stress generated in the plain bearing 11 does not become excessive. Comparing the numerical values in the charts of FIG. 1 and FIG. 5, the distribution of the values of the crash, oil clearance, and compressive stress generated by the selective mating method of the present invention is higher than those of the conventional selective mating method. Then, it is understood that it is within a narrower ideal range, particularly within a range where the upper limit is reduced.

FIG. 2 shows the expansion amount of the crash and the housing diameter. As described above, the crush is the tightening allowance (circumferential length) given to the plain bearings to fit and fix the plain bearings 11 in the housing 12. As a result, the inner diameter is increased in the housing 12. In the embodiment of FIG. 1 of the present invention, the distribution range of the crash is 0.044 mm to 0.087 mm as shown in the same drawing, while in the conventional example of FIG. 5, the distribution range of the crash is 0.044 mm. mm to 0.112 mm. In other words, the upper limit of the crash has been reduced from 0.112mm to 0.087mm. For this reason, the expansion amount (maximum value) of the inner diameter of the housing 12 resulting from the crush also decreases, and in the example of FIG. 2, it decreases by about 3 μm. If the expansion of the housing diameter decreases, the shaft 10
It is possible to suppress variations in the oil clearance between the flat bearing 11 and the flat bearing 11.

The numerical values shown in the illustrated embodiment correspond to a reduction in the foot height H of the plain bearing 11 on the side of which the wall thickness is smaller than that of the conventional method. However, the present invention is not limited to this because it has a property of changing depending on which dimension is used as a reference. Further, in the foot height H of the embodiment, the large and small allowable ranges in the respective classifications a, b, and c partially overlap between the adjacent classifications, and therefore, there is an advantage that the manufacturing is easy. It is also possible to narrow the permissible size range in to prevent overlap between adjacent classifications.

Numerical values given in the above embodiment, bearing 11 and housing 12
It is needless to say that the present invention is not limited to these numerical values because the number of classifications is only an example.

[Advantages of the Invention] As described above, according to the method of the present invention, when the plain bearing and the housing are classified and fitted together, not only the thickness of the plain bearing but also the circumferential length (foot height) ) Is also added as an element of classification, and after classifying the size of the wall thickness, according to the classification, the thicker one has a larger circumferential length and the smaller one has a smaller circumferential length. Since the circumferential lengths of the flat bearing and the housing, and the flat bearing and the shaft, can be fitted to each other in a more accurate manner. In other words, it is possible to prevent excessive compression stress generated in the plain bearing, prevent fretting and creep, and suppress expansion of the diameter of the housing to reduce the oil clearance between the plain bearing and the shaft. Can be prevented from becoming too large. Therefore, it is effective to obtain a higher performance engine that is small in size and light in weight and excellent in quietness, in which the occurrence of a bearing hammering sound due to an increase in oil clearance is prevented.

[Brief description of drawings]

FIG. 1 is a table showing a specific example of a selective fitting method of a plain bearing according to the present invention, FIG. 2 is a graph showing a comparison of the distribution of the crash and the expansion amount of the housing by the method of the present invention and the conventional method, and FIG. FIG. 4 is a schematic view showing a state of mounting the plain bearing, FIG. 4 is a front view showing a method for measuring the foot height (circumferential length) of the plain bearing, and FIG. 5 is an example of a conventional selective fitting method. It is a chart. 10 …… Shaft, 11 …… Plain bearing, 12 …… Housing.

Claims (2)

[Claims] 1. A plain bearing classification step of classifying a semi-cylindrical plain bearing into at least two types according to the thickness of the plain bearing; In addition, a plain bearing machining step that performs processing to make the circumferential lengths large and small so that those with a large thickness have a large circumferential length and those with a small thickness have a small length; A housing classifying step of classifying at least two types of housings for housing and holding the same; and a plain bearing classified and processed in this manner and the classified housings in a wall thickness and a circumferential direction of the plain bearing. A method of selectively fitting a plain bearing, comprising: a selective fitting step of selecting and fitting so that the length and the inner diameter of the housing match. 2. The allowance range of the circumferential length for each classification of the thickness of the plain bearing in the flat bearing processing step in the claim 1 is partly different between adjacent classifications. Selective mating method for overlapping plain bearings.