JP4366590B2 - Engine oil passage structure - Google Patents

Description

  The present invention relates to an oil passage structure of an engine, and more particularly to an oil passage structure for supplying lubricating oil from a cylinder block side to a bearing portion of a crank journal and a crank pin.

  The main bearing that rotatably supports the crank journal of the crankshaft with respect to the cylinder block and the connecting rod bearing that pivotally connects the large end of the connecting rod to the crankpin of the crankshaft are subject to the combustion pressure received by the piston. Sufficient lubrication and cooling is required because it plays the role of transmitting rotational force to the crankshaft while withstanding. For this reason, lubricating oil is supplied to the main bearing and the connecting rod bearing from the cylinder block side for lubrication and cooling (for example, see Patent Document 1).

  In the oil passage structure disclosed in Patent Document 1, a pin-side through oil passage penetrating a crank pin is connected to a journal-side through oil passage penetrating one of adjacent crank journals via a connecting oil passage. The lubricating oil is supplied from the cylinder block side into the oil groove of the main bearing to form an oil film between the crank journal and the main bearing, and a part of the supplied lubricating oil is supplied to the journal side. It is supplied to the connecting rod bearing side through the through oil passage, the connecting oil passage, and the pin side through oil passage.

  By the way, the main bearing and the connecting rod bearing are formed by joining semicircular metals from above and below, and appropriately circulate the lubricating oil that forms an oil film while leaking the lubricating oil from the metal split surface that is the contact point between the metals. Good lubrication and cooling. However, pressure loss of downstream oil passages and connecting rod bearings acts on the main bearing side, so there is a tendency for lubricating oil to leak from the metal split surface more than necessary for lubrication and cooling. A problem arises in that it is necessary to increase the capacity, which inevitably causes a decrease in engine output and a deterioration in fuel consumption.

In view of this, measures are taken to suppress the leakage of the lubricating oil from the metal split surface by causing pressure loss of the lubricant flowing in the oil groove in the vicinity of the metal split surface. As shown in FIGS. 5 and 6, in this measure, the connecting oil passage 13 is connected to the journal side through oil passage 101 a of one crank journal 101 adjacent to the pin side through oil passage 12 of the crankpin 2 as in the above-mentioned Patent Document 1. The oil groove 6 of the upper metal 4a of the main bearing 4 is formed so as to become gradually shallower downward. In addition, 14 in FIG. 5 is a plug ball which closes the opening end of the connection oil path 13. By such a shape setting, the vicinity of the metal split surface 5 of the oil groove 6 functions as the throttle portion 8 to rapidly increase the pressure loss of the lubricating oil flowing inside, thereby suppressing leakage of the lubricating oil from the metal split surface 5. The above problems have been resolved.
JP 2000-186519 A

  However, as shown in FIG. 6, when the journal side through oil passage 101 a penetrating the crank journal 101 becomes a horizontal angle as the crankshaft rotates, both ends of the journal side through oil passage 101 a are restricted by the oil groove 6. In order to cope with the part 8 at the same time, the supply of the lubricating oil to the journal side through oil passage 101a is suddenly reduced temporarily due to the pressure loss of the throttle part 8. As a result, the supply of lubricating oil to the connecting rod bearing becomes intermittent. For example, in a high-performance engine that makes heavy use of a high rotation and high load range, there is a possibility that the engine will be damaged due to insufficient lubrication of the connecting rod bearing. was there.

  The object of the present invention is to suppress the leakage of excessive lubricating oil at the metal split surface of the main bearing, and continuously supply the lubricating oil to the connecting rod bearing side without interruption to realize a good lubricating state. It is an object to provide an oil passage structure of an engine that can perform the above-mentioned.

In order to achieve the above object, the invention of claim 1 is characterized in that a crank journal of a crankshaft is rotatably supported by a bearing portion of a cylinder block, a connecting rod is connected to a crankpin of the crankshaft, and an inner periphery of the bearing portion is provided. Engine oil that forms an oil groove and supplies lubricating oil from the cylinder block side to the oil groove, and supplies the lubricating oil supplied to the oil groove from the crank journal to the crank pin through an oil passage formed in the crankshaft. In the road structure, a throttle portion that increases the pressure loss of the lubricating oil is formed at a specific location in the circumferential direction in the oil groove of the bearing portion, and the oil passage is substantially parallel to the crank journals located on both sides of the crankpin. penetrated by a through oil passage as, and both through oil passages, respectively have a connecting oil passage communicating with the crank pin side, the crank pin through the through oil passage and the connection oil passage and Kurankupi And of the crank journal located on both sides each communicating supplies the lubricating oil to the crank pin respectively from the oil groove of the bearing portion for supporting the both crank journal, both through oil passage with respect to the center of each crank journal The through oil passages that are eccentric to the opposite sides and open on the outer peripheral surfaces of both crank journals correspond to the throttle portions of the respective oil grooves at different crank angles.

  Accordingly, the lubricating oil is supplied to the oil groove of the bearing portion from the cylinder block side, and the supplied lubricating oil is supplied to the crankpin through the oil passage of the crankshaft. At a specific location in the circumferential direction of the oil groove, the pressure loss of the lubricating oil increases due to the throttle portion.For example, the vicinity of the metal split surface where the upper metal and the lower metal of the bearing abut is set as the specific location. Excessive lubricant leakage from the surface is suppressed.

When the oil passage opened on the outer peripheral surface of the crank journal with the rotation of the crankshaft corresponds to the throttle portion of the oil groove, the lubricating oil supplied to the crankpin decreases with an increase in pressure loss. Is supplied with lubricating oil from the crank journals on both sides through the oil passages, and the through oil passages penetrating the crank journals are substantially parallel to each other and eccentric to the opposite side with respect to the center of the crank journal. As the crankshaft rotates, both ends of both through oil passages correspond to the throttle portions of the respective oil grooves at different crank angles, so that even if the lubricating oil supplied from one through oil passage suddenly decreases, the other Lubricating oil is sufficiently supplied from the through oil passage, and as a result, the lubricating oil is continuously supplied to the crank pin without interruption.

As described above, according to the oil passage structure of the engine of the first aspect of the present invention, the lubricating oil is supplied to the crank pins from the crank journals on both sides via the oil passages, and the oil passages on the outer peripheral surfaces of both crank journals are provided. However, even if the lubricating oil pressure is lost by the throttle portion and the lubricating oil supplied from one oil passage is reduced, the oil portion is sufficiently removed from the other oil passage. Lubricating oil is supplied, and as a result, the lubricating oil can be continuously supplied without interruption to the crankpin to achieve a good lubricating state.

Hereinafter, an embodiment of an oil passage structure of an engine embodying the present invention will be described.
FIG. 1 is a cross-sectional view of a crankshaft to which an oil passage structure of an engine of the present embodiment is applied, and FIG. 2 is a cross-sectional view showing a connection state between a journal side through oil passage and a pin side through oil passage formed in the crankshaft. 3 is a cross-sectional view taken along the line III-III in FIG. 1 showing the journal side through oil passage of the crankshaft when corresponding to the oil groove of the main bearing, and FIG. 4 is a view of the crankshaft when not corresponding to the oil groove of the main bearing. It is the IV-IV sectional view taken on the line of FIG. FIG. 2 shows an overall cross section of the same location as FIG.

  The engine of this embodiment is configured as an in-line four-cylinder five-bearing gasoline engine. As shown in FIG. 1, crank journals 1a and 1b are formed at five locations on the crankshaft, and between the crank journals 1a and 1b. Crank pins 2 for each cylinder are formed at four locations via crank webs 3. Since the engine is designed to explode at equal intervals of 180 ° CA, the crankpins 2 of the # 1 and # 4 cylinders and the crankpin 2 of the # 2 and # 3 cylinders are opposite to each other centering on the crank journals 1a and 1b ( They are decentered in the vertical direction of FIG. 1 and have 180 ° CA phases different from each other.

  The crank journals 1a and 1b of the crankshaft are rotatably supported between a crank support portion formed in a cylinder block (not shown) and a crank cap bolted to the crank support portion from below. Specifically, as shown in FIGS. 3 and 4, a semicircular upper metal 4a that opens downward is fitted into the crank support portion, and a semicircular lower metal 4b that opens upward is fitted into the crank cap. An annular main bearing 4 (bearing portion) is formed by the upper metal 4a and the lower metal 4b, and the crank journals 1a and 1b of the crankshaft are held in the main bearing 4 in a state where a predetermined oil clearance is formed. In the following description, the contact portion between the upper metal 4a and the lower metal 4b is referred to as a metal split surface 5.

  A single oil groove 6 is formed on the entire inner circumference of the upper metal 4a in the circumferential direction, and one side of the oil groove 6 communicates with a main gallery (not shown) on the cylinder block side through an oil hole 7 that penetrates the upper metal 4a. The lubricating oil from the oil pump is supplied from the main gallery through the oil hole 7 into the oil groove 6. The oil groove 6 of the upper metal 4a is deepest at the uppermost part of the upper metal 4a, gradually becomes shallower downward, and the vicinity of the lowermost metal split surface 5 is shallowest. For this reason, the cross-sectional area of the oil groove 6 is abruptly reduced in the vicinity of the metal split surface 5, and this portion functions as a throttle portion 8 that causes pressure loss in the lubricating oil flowing inside. In contrast to the upper metal 4a in which the oil groove 6 is formed in this way, the inner periphery of the lower metal 4b is formed flat without forming an oil groove.

  In each crank journal 1a, 1b and each crankpin 2 of the crankshaft, a direction perpendicular to the eccentric direction (vertical direction in FIG. 1) of the crankpin 2 with respect to the crank journal 1a, 1b (direction perpendicular to the plane of FIG. 1). The oil passages of the crank journals 1a and 1b are hereinafter referred to as journal side through oil passages 11a and 11b, and the oil passage of the crank pin 2 is hereinafter referred to as pin side through oil passage 12. Each crank web 3 of the crankshaft is provided with a connecting oil passage 13 obliquely, and the adjacent journal side through oil passages 11a and 11b and the pin side through oil passage 12 communicate with each other through the connection oil passage 13. As shown in FIG. 2, the oil passages 11a, 11b, 12, and 13 are substantially H-shaped as a whole. In addition, the plug ball 14 is press-fitted and blocked at a location where each connecting oil passage 13 is open to the crank web 3.

  Here, the pin side through oil passage 12 of the prior art shown in FIGS. 5 and 6 communicates with only one of the adjacent journal side through oil passages 101a via the connection oil passage 13, whereas The pin side through oil passage 12 of the present embodiment communicates with both the journal side through oil passages 11a and 11b on both sides via a connection oil passage 13. As shown in FIG. 1, the crank journal 1a and the crank journal 1b are alternately arranged in the longitudinal direction of the crankshaft, and are formed in the journal side through oil passage 11a and the crank journal 1b formed in the crank jar journal 1a. The journal side through oil passages 11b are parallel to each other and eccentric to the opposite side.

  That is, in the arrangement state of the crankshaft shown in FIG. 1, the journal side through oil passage 11a is eccentric upward by an offset amount L with respect to the center of the crank journal 1a as shown in FIG. The side through oil passage 11b is eccentric downward by an offset amount L with respect to the center of the crank journal 1b. Therefore, the journal side through oil passages 11a, 11b located on both sides of each pin side through oil passage 12 are eccentric to the opposite sides with respect to the centers of the crank journals 1a, 1b, and these journal side through oil passages 11a, 11b, 11 b communicates with the common pin side through oil passage 12.

The pin side through oil passage 12 is formed so as to coincide with the center of the crank pin 2 with respect to the crank journals 1a and 1b formed in such a manner that the journal side through oil passages 11a and 11b are eccentric.
On the other hand, although not described in detail, each crankpin 2 of the crankshaft is connected to a large end portion of a connecting rod of each cylinder, and the large end portion of the connecting rod is connected via a connecting rod bearing having the same configuration as the main bearing 4. Thus, it can swing with respect to the crankpin 2.

Next, a description will be given of the state of supply of lubricating oil during engine operation in the engine oil passage structure of the present embodiment configured as described above.
During the operation of the engine, the pistons of the respective cylinders sequentially receive the combustion pressure and press the crankpin 2 from above via the connecting rod, whereby rotational force is applied to the crankshaft and rotational driving is performed. At this time, the crank journals 1a and 1b of the crankshaft rotate in the main bearing 4, and the crankpin 2 of the crankshaft rotates in the connecting rod bearing.

  On the other hand, with the operation of the engine, lubricating oil is discharged from the oil pump and supplied to the main gallery, and a part of the lubricating oil passes through the oil holes 7 of the upper metal 4a of each main bearing 4 from the main gallery and enters the oil groove 6. To be supplied. The supplied lubricating oil forms an oil film between the inner periphery of each main bearing 4 and the outer periphery of the crank journals 1a and 1b of the crankshaft, thereby providing lubrication and cooling action, and part of the lubricating oil is separated from the upper metal 4a. It leaks to the outside, that is, into the cylinder block through a minute gap between the metal split surface 5 and the lower metal 4b, and is collected in the oil pan. Thus, the lubricating oil that forms an oil film due to leakage from the metal split surface 5 circulates appropriately, so that the lubricating oil having a low temperature always exhibits good lubrication and cooling action.

  The remaining lubricating oil that has not leaked from the metal split surface 5 is introduced into the journal side through oil passages 11a and 11b of the crank journals 1a and 1b, and further from the pin side through oil passage 12 through the connection oil passage 13 to the crankpin. 2 is supplied to the outer periphery. As in the case of the main bearing 4, the supplied lubricating oil forms an oil film between the outer periphery of the crankpin 2 and the inner periphery of the connecting rod bearing, and is used for lubrication and cooling. Leak outside.

  Here, since the pressure loss generated by the downstream oil passages 11a, 11b, 12, 13 and the connecting rod bearing acts on the main bearing 4, the metal dividing surface 5 of the main bearing 4 is compared with the connecting rod bearing side. Tends to leak more than needed for lubrication and cooling. However, as described above, in this embodiment, the throttle portion 8 is provided in the vicinity of the metal split surface 5 of the oil groove 6 of the upper metal 4a to cause pressure loss in the lubricating oil. As a result, it is not necessary to increase the capacity of the oil pump as a countermeasure against the leakage of the lubricating oil, and a decrease in engine output and a deterioration in fuel consumption due to this can be avoided.

  In the present embodiment, the pin-side through oil passages 12 of each crank pin 2 communicate with both of the journal-side through oil passages 11a and 11b on both sides via the connection oil passage 13 and on both sides. Since the located journal side through oil passages 11a and 11b are eccentric to the opposite sides with respect to the centers of the crank journals 1a and 1b, the supply of lubricating oil from the main bearing 4 side to the connecting rod bearing side will be described below. To be done.

  For example, when one of the journal side through oil passages 11a located on both sides of the crankpin 2 is positioned above the center of the crank journal 1a as shown by the solid line in FIG. The journal side through oil passage 11b is positioned below the center of the crank journal 1b as shown by the solid line in FIG. At this time, although both ends of the other journal side through oil passage 11b correspond to the lower metal 4b, no lubricating oil is directly supplied from the oil groove 6, but both ends of the one journal side through oil passage 11a are oil of the upper metal 4a. Corresponding to the groove 6 and being offset from the center of the crank journal 1a so as to be separated from the throttle portion 8, a sufficient amount of lubrication from the oil groove 6 without being affected by pressure loss due to the throttle portion 8 Supplied with oil.

  Further, when the crankshaft further rotates in the direction of the white arrow in FIG. 3 from the above angle, one end of one journal side through oil passage 11a moves downward as indicated by a broken line, so that lubrication corresponding to the lower metal 4 is performed. Although the oil is not supplied, the other end of the journal side through oil passage 11a moves upward to correspond to a deeper portion of the oil groove 6, so that a sufficient amount continues in one journal side through oil passage 11a. Of lubricating oil is supplied.

  On the other hand, when the crankshaft rotates by 180 ° CA from the initial angle, the positional relationship between both journal side through oil passages 11a and 11b shown in FIGS. However, both ends of the other journal side through oil passage 11b are separated from the throttle portion 8 and are not affected by the pressure loss, so that a sufficient amount from the oil groove 6 is obtained. Lubricant is supplied.

  As described above, both ends of the journal side through oil passages 11a and 11b correspond to the throttle portions 8 of the respective oil grooves 6 with different crank angles (crankshaft rotation angles) as the crankshaft rotates. In other words, regardless of the crank angle, at least one end of one of the journal side through oil passages 11a, 11b is always spaced from the throttle 8 and corresponds to the oil groove 6 of the upper metal 4a. Lubricating oil is supplied to the connecting rod bearing through the side through oil passages 11a and 11b.

  That is, there is no possibility that the supply of the lubricating oil becomes intermittent as in the prior art of FIGS. 5 and 6 in which both ends of the journal side through oil passage 101a simultaneously correspond to the throttle portion 8 of the oil groove 6. The lubrication oil can be continuously supplied to the bearing without interruption to achieve a good lubrication state. Therefore, even when applied to a high-performance engine that frequently uses a high rotation and high load range, engine breakage due to insufficient lubrication of the connecting rod bearing can be avoided.

This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in the above embodiment, the engine is configured as an in-line four-cylinder five-bearing gasoline engine, but the type of engine to be applied is not limited to this, and can be variously changed. For example, the number of cylinders or the cylinder arrangement can be changed, diesel It may be applied to the engine.
In the above embodiment, the journal side through oil passages 11a and 11b on both sides of the pin side through oil passage 12 are parallel to each other and eccentric to the opposite side. However, the present invention is not limited to this. The oil passages 11a and 11b may be formed at different angles after being aligned with the centers of the crank journals 1a and 1b without being eccentric. Even in this case, since both ends of both journal side through oil passages 11a and 11b correspond to the narrowed portion 8 of the oil groove 6 at different crank angles as the crankshaft rotates, the same effect as the above embodiment can be obtained. Can do.

It is sectional drawing of the crankshaft to which the oil path structure of the engine of embodiment was applied. It is a sectional side view which shows the connection state of the journal side through oil path and pin side through oil path which were formed in the crankshaft. FIG. 3 is a cross-sectional view taken along the line III-III in FIG. 1 showing a journal side through oil passage of a crankshaft when corresponding to an oil groove of a main bearing. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1 showing a journal-side through oil passage of the crankshaft when not corresponding to the oil groove of the main bearing. It is a fragmentary sectional view of the crankshaft to which the oil passage structure of the engine of the prior art was applied. FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5 showing a journal-side through oil passage of the crankshaft when corresponding to the throttle portion of the oil groove of the main bearing.

Explanation of symbols

1a, 1b Crank journal 2 Crank pin 4 Main bearing (bearing part)
6 Oil groove 8 Restricted portion 11a, 11b Journal side through oil passage (oil passage)
12 pin side through oil passage (oil passage)
13 Connection oil passage (oil passage)

Claims (1)

A crank journal of the crankshaft is rotatably supported on the bearing portion of the cylinder block, a connecting rod is connected to the crankpin of the crankshaft, an oil groove is formed on the inner periphery of the bearing portion, and the cylinder block side In the oil passage structure of the engine that supplies the lubricating oil to the oil groove and supplies the lubricating oil supplied to the oil groove from the crank journal to the crankpin through an oil passage formed in the crankshaft.
The oil groove of the bearing portion is formed with a throttle portion that increases the pressure loss of the lubricating oil at a specific location in the circumferential direction.
The oil passage includes a through oil passage penetrating through the crank journal located on both sides of the crankpin so as to be substantially parallel to each other, and a connecting oil passage communicating the both through oil passages with the crankpin side. The crank pin and the crank journals on both sides are communicated with each other through the through oil passage and the connection oil passage, respectively, and lubricating oil is supplied to the crank pin from the oil groove of the bearing portion supporting both crank journals. And the through oil passages are eccentric to the opposite sides with respect to the centers of the crank journals, and the through oil passages opened on the outer peripheral surfaces of the crank journals are in contact with the throttle portions of the oil grooves. The oil passage structure of the engine is characterized by being able to handle different crank angles.

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