JP2001050252A - Slide bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an occurrence of cavitation by preventing abrupt opening and closing of an oil passage receiving a lubricating oil supplied from an oil groove formed on a shaft side in regard to a slide bearing having an oil groove formed with ends in an inner circumference along a circumferential direction. SOLUTION: An extension groove 13 extending in a circumferential direction from both ends of an oil groove 12 is formed and a width of this extension groove 13 is set smaller than a bore of an inlet 16a of an oil passage. By this, the inlet 16a of the oil passage formed on a shaft transits to a fully-opened state by the oil groove 12 via a half-opened state by the extension groove 13 during opening for preventing abrupt opening of the inlet 16a. Thereby, abrupt changes of a flow of a lubricating oil is prevented and an occurrence of cavitation is effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding bearing having an oil groove formed on the inner periphery thereof so as to have an end along the circumferential direction.

[0002]

2. Description of the Related Art In an engine such as an automobile, a main bearing for receiving a main shaft portion of a crankshaft, a crankpin bearing for receiving a crankpin, a piston pin bearing for receiving a piston pin,
Various bearings, such as a cam bearing for receiving a camshaft and a rocker arm bearing for receiving a rocker arm, are provided. These bearings are supplied with lubricating oil. The distribution of lubricating oil to the main bearing attached to the cylinder block, the crankpin bearing attached to the large end of the connecting rod, and the piston pin bearing attached to the small end of the connecting rod is performed as follows.

[0003] A main passage is formed in the engine block, and lubricating oil discharged from a lubricating oil pump is pressure-fed to the main passage. On the other hand, an oil groove is formed on the inner periphery of the main bearing. The oil groove communicates with the main passage by an oil hole formed in the main bearing.

[0004] An oil passage extending from the main shaft to the crankpin is formed in the crankshaft to guide the lubricating oil supplied to the oil groove of the main bearing to the crankpin bearing. The inlet of the oil passage of the crankshaft is formed on the outer peripheral surface of the main shaft portion at an position corresponding to the oil groove of the main bearing, and the outlet is formed on the inner peripheral surface of the crankpin bearing on the outer peripheral surface of the crankpin. It is formed at a position corresponding to the groove.

[0005] The connecting rod has an oil passage for guiding lubricating oil supplied to the crankpin bearing to the piston pin bearing. An oil hole communicating with the oil passage of the connecting rod is formed in the piston pin bearing.

In the above-described lubricating oil distribution configuration, the lubricating oil pumped from the lubricating oil pump to the main passage is fed into the oil groove from the oil hole of the main bearing. A part of the lubricating oil sent to the oil groove of the main bearing is supplied to the bearing surface of the main bearing, and the remaining part is sent to an oil passage of the crankshaft which is opened on the outer peripheral surface of the main shaft portion.

[0007] The lubricating oil fed into the oil passage of the connecting rod is supplied from the outlet of the oil passage to the oil groove of the crankpin bearing. And, of the lubricating oil supplied to the oil groove of the crankpin bearing, a part is supplied to the bearing surface of the crankpin bearing, and the remaining part is fed into the oil passage of the connecting rod from the oil hole of the crankpin bearing, The oil is supplied from the oil passage to the inner peripheral bearing surface through the oil hole of the piston pin bearing.

[0008]

The main bearing and the crankpin bearing are both constituted by split bearings. An oil groove is formed on the entire inner circumference of one split bearing, and an oil groove is partially formed on both ends in the circumferential direction of the other split bearing. A slightly longer end-shaped oil groove is formed.

In the main bearing and the crankpin bearing,
The reason why the oil groove is not formed on the entire circumference as described above and is formed as an end is that a large combustion pressure generated when fuel is burned in the cylinder acts on one side half of the main bearing and the crankpin bearing. Therefore, an attempt is made to reduce the bearing surface pressure as much as possible by not providing an oil groove that reduces the bearing area on the side where the combustion pressure acts.

The oil passage provided on the crankshaft has an inlet communicating with the oil groove of the main bearing to receive the supply of lubricating oil, and an outlet communicating with the oil groove of the crankpin bearing to send out the lubricating oil. However, since the oil groove has ends, the inlet and the outlet of the oil passage repeatedly open and close in the oil groove with the rotation of the crankshaft.

The oil groove is formed so as to have the same or wider diameter as the inlet and outlet of the oil passage over the entire length.
Therefore, at both ends of the oil groove, the inlet and the outlet of the oil passage are rapidly opened and closed from fully closed to fully open or from fully open to fully closed. When such rapid opening and closing are performed, a sudden change occurs in the flow of the lubricating oil, and as a result, cavitation occurs and the bearing surface is eroded.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sliding bearing capable of preventing sudden opening and closing of an inlet or an outlet of an oil passage to prevent cavitation.

[0013]

In order to achieve the above object, in the sliding bearing of the present invention, an extension groove extending in the circumferential direction from both ends of the oil groove is formed, and at least the tip of the extension groove is formed in the oil passage. Because the shaft is formed to have a width smaller than the diameter, the inlet or outlet of the oil passage of the shaft is in a fully opened state by the oil groove through a half-open state by the tip of the extension groove when opened, and is fully opened by the oil groove when closed. From the end of the extension groove to the half-closed state, and is completely closed, thereby preventing sudden opening and closing. Therefore, a sudden change in the flow of the lubricating oil is prevented, and the occurrence of cavitation is effectively prevented.

In this case, it is preferable that the extension groove is formed so as to become gradually narrower. Further, the depth of the extension groove can be reduced toward the tip. With this configuration, the opening or closing of the inlet or outlet of the oil passage is performed more gently, so that the occurrence of cavitation can be more effectively prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is applied to a bearing of an engine will be described below with reference to FIGS. As shown in FIG. 5, the main shaft 2 of the crankshaft 1 is received by a main bearing 3. As shown in FIG. 4, the main bearing 3 is composed of split-type plain bearings (hereinafter, referred to as half-split bearings) 4 and 5, one of which is mounted on a cylinder block 6 while the other is mounted on a cylinder block 6. Half bearing 5
Is attached to the bearing cap 7. Then, by fixing the bearing cap 7 to the cylinder block 6, 2
The half bearings 4 and 5 are configured as cylindrical main bearings 3 and support the main shaft 2 of the crankshaft 1.

A large end 9a of a connecting rod 9 is connected to the crank 8 of the crank shaft 1. Inside the large end 9a, there is a crank pin 8a as a shaft.
A crank pin bearing 10 for receiving the power is mounted. This crankpin bearing 10 is also composed of two half bearings 11 and 12 like the main bearing 3 described above.

The cylinder block 6 has a main passage 11 for supplying the main bearing 3 with lubricating oil fed from a lubricating oil pump (not shown). This main passage 1
In order to take in the lubricating oil sent through 1, a circumferentially extending end-shaped oil groove 12 is formed on the inner periphery of the main bearing 3. That is, of the two half bearings 4 and 5 constituting the main bearing 3, the half bearing 5 on the bearing cap 7 side includes:
The combustion pressure at which the fuel is burned in the cylinder acts. For this reason, the burden load of the half bearing (hereinafter, lower half bearing) 5 on the bearing cap 7 side is larger than that of the half bearing (hereinafter, upper half bearing) 4 on the cylinder block 6 side. A groove 4a extending in the circumferential direction is formed in the inner periphery of the upper half bearing 4 on the light load side at the center in the axial direction, and is formed over the entire periphery.
Further, on the inner periphery of the lower half bearing 5 on the high load side, in order to avoid an excessive bearing surface pressure, partial grooves 5a, 5 extending in the circumferential direction are provided.
b are formed only at both ends in the circumferential direction at the center in the axial direction.

As shown in FIG. 3, when the bearing cap 7 is attached to the cylinder block 6 and the lower half bearing 5 is abutted against the upper half bearing 4, the partial grooves 5a and 5b of the lower half bearing 5 The groove 4 is connected to both ends of the groove 4 a of the half bearing 4.
The end-shaped oil groove 12 is formed together with a. Then, from the front ends of the partial grooves 5a and 5b of the lower half bearing 5 which are both ends of the oil groove 12, the extension grooves 1 which are narrower than the partial grooves 5a and 5b.
3 and 14 are formed. Such an oil groove 12 communicates with the main passage 11 of the cylinder block 6 by an oil hole 15 formed in the upper half bearing 4.

The crankshaft 1 is provided with an oil passage 16 for guiding the lubricating oil fed into the oil groove 12 of the main bearing 3 to the crankpin bearing 10. The inlet 16 a of the oil passage 16 is opened on the outer peripheral surface of the main shaft portion 2 and is located corresponding to the oil groove 12 of the main bearing 3.

Here, as shown in FIG. 1, the oil groove 12 (groove 4
a, 5a, 5b), the width b of the extension grooves 13 and 14, and the diameter D of the inlet 16a of the oil passage 16 are described. The width B of the oil groove 12 is larger than the diameter D of the inlet 16a. The width b of the extension grooves 13 and 14 at both ends of the oil groove 12 is set smaller than the diameter D of the inlet 16a.

As shown in FIG. 2, the entire depth of the oil groove 12 including the extension grooves 13 and 14 is uniform over the entire circumference of the groove 4a, and the depth of the partial grooves 5a and 5b and the extension grooves 13 and 14 is uniform. Are formed so as to gradually become shallower toward the tip. FIG. 2 shows the partial groove 5a and the side of the extension groove 13 extending from the partial groove 5a, and the same applies to the partial groove 5b and the side of the extension groove 14 extending from the partial groove 5b.

The oil groove 17 similar to the oil groove 12 of the main bearing 3 as described above is also formed on the inner periphery of the crankpin bearing 10. The outlet 16 of the oil passage 16 of the crankshaft 1
“b” is opened on the outer peripheral surface of the crankpin 8 a and is located at a position corresponding to the oil groove 17 of the crankpin bearing 10.

The connecting rod 9 has an oil passage 20 for supplying lubricating oil supplied to the crankpin bearing 10 to a piston pin bearing (not shown).
One end of the oil passage 20 is communicated with an annular groove 21 formed on the large end 9 a of the connecting rod 9 so as to surround the outer periphery of the crankpin bearing 10. And
The oil groove 17 on the inner periphery is formed in the
An oil hole 22 is formed to communicate with the first hole. In addition, the other end of the oil passage 20 of the connecting rod 9 is
It communicates with an oil hole formed in a piston pin bearing (not shown).

Next, the operation of the above configuration will be described. During operation of the engine, lubricating oil pumped into the main passage 11 from a lubricating oil pump (not shown) is fed from the oil hole 15 into the oil groove 12 on the inner periphery of the main bearing 3. Part of the lubricating oil fed into the oil groove 12 is supplied to the bearing surface of the main bearing 3 to lubricate the space between the main shaft portion 2 of the crankshaft 1 and the remaining lubricating oil flows to the oil passage 16 of the crankshaft 1. It is sent from the entrance 16a.

The lubricating oil fed into the oil passage 16 of the crankshaft 1 is discharged from an outlet 16b into an oil groove 17 of the crankpin bearing 10. A part of the lubricating oil discharged into the oil groove 17 is supplied to the bearing surface of the crankpin bearing 10 to lubricate between the lubricating oil and the crankpin 8a, and the remaining lubricating oil flows from the oil hole 22 through the annular groove 21. And is sent out to the oil passage 20 of the connecting rod 9. Then, the lubricating oil sent out to the oil passage 20 is supplied to an inner bearing surface of the piston pin bearing from an oil hole (not shown) of the piston pin bearing.

The inlet 16a of the oil passage 16 of the crankshaft 1 is opened in the oil groove 12 of the main bearing 3 as the crankshaft 1 rotates, The state of being closed by the surface is alternately repeated.
Therefore, the lubricating oil flows from the oil groove 12 into the oil passage 16 intermittently.

Here, a change in the degree of opening of the inlet 16a to the oil groove 12 when the inlet 16a of the oil passage 16 shifts from closed to open will be described with reference to FIG. When the inlet 16a is at the position shown in FIG. 1A, the inlet 16a is closed by the bearing surface of the main bearing 3 (shown by hatching). From this state, the crankshaft 1 rotates and the inlet 16
When “a” starts to hang on the tip of the extension groove 13, the inlet 16 a starts to open into the oil groove 12 including the extension groove 13, and the opening area of the inlet 16 a to the extension groove 13 becomes (A) to (B).
It gradually increases as shown in (e).

However, the width “b” of the extension groove 13 is
Since it is smaller than the diameter D of 6a, even if the inlet 16a comes to the position shown in (e) where it completely overlaps with the extension groove 13, it is not completely opened. Thereafter, when the inlet 16a comes to engage with the oil groove 12 as shown by (f) due to the rotation of the crankshaft 1, the width B of the oil groove 12 is larger than the diameter of the inlet 16a. When it increases and the inlet 16a completely overlaps the oil groove 12 as shown in (g), the inlet 16a becomes a complete opening.
Thereafter, the entrance 16a moves in the direction indicated by the arrow A in FIG.

As described above, when the inlet 16a shifts from the closed state to the open state, the extended groove 13 having a width smaller than the diameter of the inlet 16a exists before the oil groove 12, so that the inlet 16a is in a half-open state compared to a case where it is not present. Is maintained for a long time, so that the entrance 16a does not suddenly shift from the fully closed state to the fully opened state, but relatively gradually shifts from the fully closed state to the fully opened state via the half open state. For this reason, the lubricating oil in the oil groove 12 is
When the oil starts to flow into the oil passage 16, the amount of the inflow increases relatively slowly, so that the change in the flow of the lubricating oil becomes gentle and cavitation can be effectively prevented. .

In this case, the depth of the extension groove 13 is set at the inlet 16a.
, The sectional area of the extension groove 13 gradually increases from “0”. For this reason, the throttle of the inlet 16a is gradually opened, so that the change in the flow of the lubricating oil becomes more gentle, and the occurrence of cavitation can be more effectively prevented.

Similarly, when the inlet 16a moves from the open state to the closed state, the extension groove 1 is moved from the fully open state where it completely overlaps the oil groove 12.
Since the transition to the fully closed state is made through the half-open state overlapping with No. 4, when the flow of the lubricating oil from the oil groove 12 into the oil passage 16 is stopped, the amount of the flow is reduced relatively slowly. Become. For this reason, the change in the flow of the lubricating oil becomes gentle, and the occurrence of cavitation can be effectively prevented.

In the main bearing 3, the state in which the opening degree of the inlet 16 a of the oil passage 16 with respect to the oil groove 12 gradually changes depends on the opening degree of the outlet 16 b of the oil passage 16 with respect to the oil groove 17 of the crankpin bearing 10. Is also obtained,
A sudden change in the discharge amount of the lubricating oil from the outlet 16b of the oil passage 16 is prevented, and the occurrence of cavitation is prevented.

FIG. 6 shows a second embodiment of the present invention.
The difference from the first embodiment is that the width of the extension groove 23 is gradually reduced toward the front end, and the width is continuously reduced by making the front end triangular. With this configuration, when the inlet 16a changes from closed to open and from open to closed, the opening area of the inlet 16a changes more gently. It becomes moderate and cavitation can be prevented more effectively.

The present invention is not limited to the embodiment described above and shown in the drawings, but can be extended or modified as follows. The width of the oil groove 12 is the inlet 1 of the oil passage 16.
The diameter of the extension grooves 13, 14, and 23 may be smaller than the diameter of the oil groove 12 and the inlet 16a. The extension groove may have a triangular shape as a whole so that the width of the extension groove changes continuously. At this time, the base end side of the extension groove (partial groove 5a, 5b side)
In this case, the diameter may be wider than the diameter D of the inlet 16a. The present invention is not limited to bearings for automobile engines, but can be widely applied to general plain bearings.

[Brief description of the drawings]

FIG. 1 is a front view of an oil groove showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view of a main bearing portion of the engine.

FIG. 4 is an exploded perspective view of a main bearing.

FIG. 5 is a longitudinal sectional view showing an engine crankshaft and its bearing.

FIG. 6 is a view corresponding to FIG. 1, showing a second embodiment of the present invention.

[Description of References] In the drawings, 1 is a crankshaft, 3 is a main bearing (slide bearing),
4, 5 are half bearings, 9 is a connecting rod, 10 is a crankpin bearing, 12 is an oil groove, 13, 14 are extension grooves,
Reference numeral 15 denotes an oil hole, 16 denotes an oil passage, 16a denotes an inlet, and 23 denotes an extension groove.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Sohei Yamada, 2 Sanagecho, Kita-ku, Nagoya City Inside (72) Inventor Atsushi Okado, 2nd Sanagecho, Kita-ku, Nagoya City Daido Metal Industry Co., Ltd. (72) Inventor Kotaro Kashiyama 2 Sanage-cho, Kita-ku, Nagoya-shi Daido Metal Industry Co., Ltd. F-term (reference) 3J011 AA07 BA02 BA13 CA01 JA02 KA02 MA06

Claims (3)

[Claims] 1. A slide bearing for supporting a shaft having an oil passage, wherein lubricating oil is supplied from the oil passage which is formed in an inner periphery to have an end along a circumferential direction and opens on an outer peripheral surface of the shaft. An oil groove for supplying lubricating oil to the oil passage or the oil passage; and an extension groove extending in a circumferential direction from both ends of the oil groove and having at least a tip portion having a width smaller than an opening diameter of the oil passage. And sliding bearing. 2. The sliding bearing according to claim 1, wherein said extension groove is formed so as to become gradually narrower. 3. The sliding bearing according to claim 1, wherein the depth of the extension groove is reduced toward the tip.