JPH07279967A - Device for machining sliding bearing - Google Patents

Abstract

PURPOSE:To manufacture a sliding bearing which can prevent seizure and wearresistance by forming a recess which is continuous circumferentially of an adapter and which has its inner surface with a widthwise sectional shape such as to have a flat center part and rise-up opposite end parts. CONSTITUTION:The inner surface of an adapter 2 has rise-up parts 2-1, 2-1 at opposite ends thereof in the widthwise direction of a bearing, and a flat part 2-2 in the inside inner surface thereof. Such a sectional shape structure is formed continuously in the circumferential direction. When an adapter 2 is attached thereto with a bearing metal 3, the rear surface of the bearing metal 3 is therefore made into close contact with the flat part 2-2 while both ends are bent inward. In this condition, the slide surface of the bearing metal 3 is machined by a broach cutter 1 in order to remove its margin. After the machining, the bearing is fitted in a flat adapter 2', there can be provided a bearing metal 3 having chamfered surfaces 3-1 at opposite ends of the bearing slide surface thereof, and a flat part 3-2 in the inside thereof. With this arrangement, it is possible to prevent seizure and abrasion due to eccentric contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slide bearing machining apparatus, and more particularly to a slide bearing machining apparatus used around a crankshaft for converting reciprocating motion into rotary motion in an internal combustion engine or a compressor.

[0002]

2. Description of the Related Art In an ordinary internal combustion engine, the crankshaft receives a large pressure due to an explosion and a high speed rotation between a connecting rod connected to a piston and a crankshaft and between a crankshaft and an engine block. Therefore, a plain bearing made of a bearing metal that supports with an oil film interposed is used. In particular, in a connecting rod bearing between a connecting rod and a crankshaft, the crankshaft is inclined or bent, so that there is a tendency for one-sided contact with the axial end portion of the slide bearing to cause an excessive edge load.

Therefore, the thickness of the central portion of the bearing metal in the axial (widthwise) cross section is made thicker than that at both ends, that is, the crowning shape is provided with a curved surface in the bearing widthwise direction. It has been proposed to prevent excessive edge loading due to a hit. By the way, the bearing metal of the slide bearing is usually composed of two semi-cylindrical bearing metal halves, and each of the semi-cylindrical bearing metal halves is shown in the top view and side view of FIG. 9 (A). As shown, in order to reduce the effect of vertical deformation of the bearing when a large load is applied, the effect of misalignment, positive formation of wedge oil film, and securing the amount of cooling oil, the circumferential direction of the semi-cylindrical surface It has an oil-relief shape in which the thickness (t) of both side portions in the circumferential direction is smaller than the thickness (T) of the central portion. Generally, the oil relief t is in the range of the upper limit t = T-5 μm to the lower limit t = T-15 μm, and T is about 1.484 to 1.496 mm. As shown in the enlarged cross-sectional views of FIGS. 9A and 9B, slight chamfers are formed on the inner surfaces of both ends in the width direction of the bearing metal for deburring and edge reinforcement. Has been done.

Further, as shown in FIG. 10, when the bearing is attached to the bearing stand or the holder is attached to the housing for machining, the adhesion force to the bearing stand or the housing is secured, and the bearing In order to dissipate heat, a tightening margin Crs, which is a protrusion of 10 to 50 .mu.m, that is, crush height Crs, is formed at the circumferential end. Note that FIG.
0 is an example of this crash height measurement method,
It is an explanatory view for explaining crash height.

FIG. 11 is an explanatory view for explaining an example of a processing method for producing the above-described crowning-shaped bearing metal, and a semi-cylindrical holder having a cylindrical inner surface that matches the cylindrical surface of the bearing metal. The housing (or adapter, hereinafter simply referred to as an adapter) of two is attached to a cylindrical adapter, and two semi-cylindrical bearing metals are attached, and the broach cutter is used to cut from the direction of the arrow. In this case, as shown by the cross section in FIG. 12, the adapter has a concave curved surface in the width direction of the bearing metal so that the diameter of both ends in the central axis direction is smaller than the diameter of the central portion. A curved surface is formed so as to have, and a bearing metal having a substantially constant thickness is attached to an adapter having such a shape. At this time, a pressing force is applied to the bearing metal by the above-mentioned crash height, and the back surface of the bearing metal closely adheres to the curved surface of the inner surface of the adapter.

In this state, the cutter shaft of the broach cutter is made parallel to the central axis of the adapter, and the bearing sliding surface is broached. At this time, as shown by the hatching in FIG. 11, the oil relief shape described above is formed by cutting so that the machining allowance of the inner surface broach becomes thicker toward the both ends in the circumferential direction, and the width of the bearing metal is also formed. The directional cross section is cut as indicated by the alternate long and short dash line in FIG. When the bearing metal processed in this way is attached to an adapter (or bearing stand) with a flat inner surface, the bearing sliding surface becomes thicker in the widthwise central part and thinner toward both ends, as shown in FIG. Thus, the bearing metal formed in the crowning shape having the crowning amount c can be obtained.

[0007]

However, when a crowning bearing metal is manufactured using the adapter having a curved surface as described above, the back surface of the bearing metal cannot partially follow the curved surface, and the bearing metal does not move in the circumferential direction. There is a problem in that unevenness may occur, so that an excessively cut portion occurs during processing, and as a result, the strength of the plain bearing cannot be ensured. In addition, when the bearing metal closely follows the concave curved surface of the adapter and deforms in the width direction, if it deforms with a curvature larger than the curvature of the adapter, the inner surface of the bearing metal may rise, and the margin is There is also a problem in that the inner surface of the bearing metal does not become a continuous shape in the circumferential direction due to the increase in the number, and seizure and wear easily occur.

Further, as described above, since the center portion and the both end portions in the circumferential direction of the semi-cylindrical bearing metal are different from each other, as shown by the cross section of both portions in FIG. It changes so that the amount of crowning increases toward both ends (c ₁ <c ₂ ). As described above, since the crowning amount c is not constant in the circumferential direction, there is a problem that seizure or wear of the bearing metal is likely to occur.

Furthermore, if the sliding surface of the bearing metal has a crowning shape in the entire width direction, a local contact occurs at the center portion of the bearing metal in the width direction,
Although it is possible to prevent uneven contact at both ends, on the contrary, there is a problem that seizure or abrasion is likely to occur at the central part. Therefore, an object of the present invention is to provide a sliding bearing machining apparatus that is easy to manufacture and that can produce a sliding bearing without seizure or wear.

Another object of the present invention is to provide a processing apparatus for a slide bearing, which is capable of producing a slide bearing which is not deformed during processing and therefore is free from seizure or wear.

[0011]

SUMMARY OF THE INVENTION A slide bearing machining apparatus according to the present invention has an inner peripheral surface having a recess continuously formed in the circumferential direction, and at least an inner peripheral surface including the continuous recess. Has a cylindrical holder to which the slide bearing to be machined is mounted and a cutter shaft parallel to the center axis of the holder, and at least both sides of the inner peripheral surface of the slide bearing mounted to the holder are machined. In a device for processing a slide bearing equipped with a broach cutter, a recess formed in a circumferential direction of the holder has a flat shape at least in the center and at both ends rising in its widthwise sectional shape. Is configured to have an inner surface that is

[0012]

According to this structure, the holder (or adapter) for bearing metal machining has a simple structure including a continuous recess having a flat portion on its inner peripheral surface, that is, a groove having a flat bottom. Therefore, the manufacturing cost of the holder is reduced and mass production becomes possible. Moreover, when a slide bearing is mounted on such a holder, the adhesion between the holder and the slide bearing is improved, and unnecessary deformation does not occur in the slide bearing. it can. Further, according to the apparatus for processing a sliding bearing of the present invention, a sliding bearing having a sliding surface having a flat center portion in a widthwise cross section and chamfered both ends is manufactured only by broaching. can do.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a conceptual configuration diagram for explaining an embodiment of a working apparatus for a sliding bearing according to the present invention, in which a bearing metal to be cut together with a broach cutter is a housing of a working holder (or an adapter; It is shown in a cross-sectional view when it is attached to an adapter. In the cross section, the inner surface of the adapter 2 has vertical rising portions 2-1 and 2-1 at both end portions in the bearing width direction, and the inner inner surfaces thereof are flat portions that are flat in the bearing width direction. 2-2, and a semi-cylindrical adapter 2 having a shape in which this cross-sectional structure is continuous in the circumferential direction and a groove having a substantially rectangular cross section extends in the circumferential direction, so to speak, a stepped adapter 2. Has been formed.

When the bearing metal 3 is mounted on the stepped adapter 2 having the above-described structure, as shown in the drawing, the back surface of the bearing metal 3 except for both sides in the width direction thereof has a flat portion 2- in the groove. It is attached so that both sides are locally bent inward. In this state, the sliding surface of the bearing metal 3 is broached by the broach cutter 1 along a cut line as shown by, for example, the alternate long and short dash line in FIG. Remove the local allowance like After processing, as shown in FIG. 2, when the adapter 2 '(or bearing stand) having a flat inner surface is assembled, chamfered portions 3-1 and 3-1 are formed at both ends of the bearing sliding surface, The bearing metal 3 having the flat shape portion 3-2 having a uniform thickness inside thereof is obtained.

According to the above-described embodiment of the apparatus for processing a slide bearing according to the present invention, since the adapter has a simple stepped structure in which the inner surface is a groove having a flat inner surface, the manufacturing cost of the adapter is low and mass production is possible. Become. Also, when bearing metal is attached to such a stepped adapter, the adhesion between the adapter and bearing metal is improved, and at the same time the deformation that occurs at the time of attachment or processing at the bent parts on both sides can be escaped to the outside. Since the bearing metal is not unnecessarily deformed, it is possible to prevent excessive cutting based on the deformation and ensure the strength of the manufactured slide bearing. In addition, unlike the chamfering corresponding to the mere deburring shown in FIG. 9 described above, only the same broaching as the conventional chamfering corresponding to the required amount of crowning as shown in FIG. The part 3-1) can be formed.

[0016] Looking at the operating conditions in the case of a connecting rod bearing, for example, the bearing base on the upper (upper) side, that is, the connecting rod side, is made of a material having high rigidity, and the deformation is small. Although a large force is applied to the edge of, the lower (lower) side, that is, the cap side bearing base is made of a material that is largely deformed, and the edge load is relatively small. FIG. 3 shows an example (5000 rpm, full load) of the oil film thickness distribution of the upper bearing, in which the oil film is extremely thin at the central portion in the bearing circumferential direction and at the widthwise both ends of that portion. That is, the gap is narrowed. Further, FIG. 4 shows an example of the temperature distribution of the same upper bearing (5000 rpm, full load), in which the temperature rises especially at the central portion in the bearing circumferential direction and at the widthwise both ends of that portion. You can see that Therefore, the contact becomes strong at this portion, and although not shown, a sliding mark is strongly generated on the bearing metal at this portion.

For such operating conditions of the slide bearing, if the bearing metal manufactured by the above-described embodiment of the processing apparatus of the present invention is used, chamfered portions 3- are formed at both ends in the width direction.
Since No. 1 is provided, it is possible to effectively prevent seizure and wear due to one-sided contact, and to obtain the same effect as the intended effect of the conventional crowning-shaped bearing metal. Moreover, according to the bearing metal having such a shape,
Since the flat portion 3-2 is provided in the central portion in the width direction, it is possible to avoid the local contact of the central portion that occurs in the case of the conventional crowning shape, and in addition, the flat portion 3-2 As a result, the thickness of the bearing metal does not change in the circumferential direction, so that seizure and wear caused by them can be prevented.

FIG. 5 is a conceptual configuration diagram for explaining a modified example of the sliding bearing machining apparatus according to the present invention, in which the bearing metal to be cut together with the broach cutter is mounted on the adapter as in FIG. Are shown in cross section. In the present modification, from the relationship between the height of the vertical rising portion 2-1 of the adapter 2 and the rigidity of the bearing metal 3,
As shown in the figure, the bearing metal 3 is mounted while being deformed with a certain curvature. Now, when broaching is performed in the cut line a, as shown in FIG. 6, a bearing metal 3 having substantially no flat portion 3-2 in the bearing metal shown in FIG. 2 is formed. Has substantially the same shape as the conventional crowning-shaped bearing metal shown in FIG. Also, for example,
When processed at the cut line b, the chamfered portion 3-1 and the flat-shaped portion 3-in the bearing metal shown in FIG.
It is possible to form the bearing metal 3 having a shape having a different ratio with respect to 2.

In this way, when the bearing metal 3 is mounted on the adapter 2 with a certain curvature, the vertical rising portion 2-1 of the adapter 2 is inside thereof, that is, the flat portion 2-.
It is not necessary for the 2 side to rise vertically, and the inclined portion 2
It is also possible to have an inclined shape with -3. Therefore, the adapter 2 has at least the flat portion 2 on its inner surface.
With the shape having -2, it is possible to realize the function and effect of the processing apparatus for a plain bearing which is the object of the present invention.

The crowning amount of the bearing metal processed in the above-described processing apparatus for a sliding bearing according to the present invention can be set based on the analysis result of the elastohydrodynamic lubrication theory. FIG. 7 is a characteristic diagram showing the analysis results of the oil film pressure and the circumferential distribution in the gap in an example of a connecting rod bearing. FIG. 7A shows the connecting rod side, and FIG. 7B shows the cap side characteristic. There is. In both figures, the curve HL in the figures is the calculation result by the fluid lubrication theory, and the curve E
HL is the calculation result by the elastohydrodynamic lubrication theory. Also,
FIG. 8 is a characteristic diagram showing the analysis result of the oil film pressure and the widthwise distribution of the gap in the example of the same connecting rod bearing, and FIG. 8A shows the characteristic on the cap side at the intake top dead center TDC. FIG. 6B shows the characteristics on the connecting rod side at the compression top dead center TDC.

From the widthwise distribution of the clearance on the connecting rod side in the compression TDC shown in FIG. 8B, the clearance calculated by EHL becomes thinner at both ends of the bearing than the clearance calculated by HL. I understand.
And the size of the gap is about 1.3 μ compared to the central part.
It is about m smaller. Therefore, if the crowning amount in the bearing width direction is set to about 2 μm, the oil film thickness can be made thicker than the result obtained by HL, which can prevent seizure and wear of the plain bearing. Becomes

[0022]

As described above, according to the slide bearing machining apparatus of the present invention, the housing or adapter of the bearing metal machining holder has a simple stepped structure including a groove having a flat portion on its inner surface. The manufacturing cost of the adapter will be low and mass production will be possible. When bearing metal is attached to such an adapter, the adhesion between the adapter and the bearing metal is improved, and unnecessary deformation does not occur in the bearing metal. The strength of the bearing can be secured.

Further, the chamfered portion corresponding to the amount of crowning required for the bearing metal can be easily formed only by the same broaching as in the conventional case, and the manufactured bearing metal has the conventional crowning shape due to the chamfered portion. It is possible to realize the effect of preventing seizure and wear due to the same one-sided contact, and it is also possible to avoid local contact in the central part by the flat shape part in the center part in the width direction.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram for explaining an embodiment of a processing device for a plain bearing according to the present invention.

FIG. 2 is a cross-sectional view for explaining the shape of a bearing metal manufactured by an embodiment of an apparatus for processing a slide bearing according to the present invention.

FIG. 3 is a characteristic diagram showing an example of an oil film thickness distribution of a sliding bearing.

FIG. 4 is a characteristic diagram showing an example of the temperature distribution of a plain bearing.

FIG. 5 is a conceptual configuration diagram for explaining a modified example of the sliding bearing processing device according to the present invention.

FIG. 6 is a cross-sectional view for explaining the shape of a bearing metal manufactured by a modification of the processing device for a slide bearing according to the present invention.

FIG. 7 is a characteristic diagram showing an analysis result of an oil film pressure and a circumferential distribution of gaps in an example of a connecting rod bearing,
(A) shows the characteristics on the connecting rod side, and (B) shows the characteristics on the cap side.

FIG. 8 is a characteristic diagram showing an analysis result of an oil film pressure and a widthwise distribution in a gap in an example of a connecting rod bearing,
(A) is a characteristic on the cap side at the intake top dead center TDC,
(B) shows the characteristics on the connecting rod side at the compression top dead center TDC.

FIG. 9 is a top view and a side view (A) showing the shape of a conventional bearing metal, and an enlarged sectional view (B).

FIG. 10 shows an example of a crash height measurement method,
It is an explanatory view for explaining crash height.

FIG. 11 is an explanatory diagram illustrating an example of a processing method for producing a conventional crowning-shaped bearing metal.

FIG. 12 is a cross-sectional view illustrating an example of a processing method for manufacturing a conventional crowning-shaped bearing metal.

FIG. 13 is a cross-sectional view for explaining the shape of a crowning-shaped bearing metal manufactured by a conventional processing method.

FIG. 14 is a cross-sectional view for explaining the shape of a crowning-shaped bearing metal manufactured by a conventional processing method.

[Explanation of symbols]

 1 ... Brooch cutter 2, 2 '... Adapter (or holder housing) 2-1 ... Vertical rising part 2-2 ... Flat part 2-3 ... Inclined part 3 ... Bearing metal 3-1 ... Chamfer part 3-2 ... Flat Shape part

Claims (1)

[Claims] 1. A cylindrical holder having an inner peripheral surface provided with recesses which are continuously provided in a circumferential direction, and a slide bearing to be machined is mounted on an inner peripheral surface including at least the continuously provided recesses. And a broach cutter having a cutter shaft parallel to the central axis of the holder and cutting at least both sides of the inner peripheral surface of the slide bearing mounted on the holder. In the holder, the recesses that are continuously provided in the circumferential direction have an inner surface that is flat in at least the central portion and has both ends raised in the widthwise cross-sectional shape of the continuously provided recesses. A processing device for plain bearings.