JPH02217607A - Bearing construction of crank shaft - Google Patents

Abstract

PURPOSE:To make possible formation of an oil hole without lowering the load withstanding strength of the shaft portion by providing the shaft portion with an oil hole which passes through near one shaft end portion, and providing shaft end portions on both sides with respective escape passages which lead from the inner face of the bearing to the outside of the shaft end portions and whose passage areas are smaller on one side and larger on the other side. CONSTITUTION:Lubricating oil in the oil passage 25 of a bearing 21 is partially forced to flow into an oil hole 15 by rotation of a journal 3 and is discharged to near the left side shaft end portion of a hourglass crank pin 5. The oil is further partially forced to flow into a communicating hole 17 and is fed also to the opposite side of the pin 5. The lubricating oil is forced to flow between the pin 5 and a bearing metal 37 while receiving the centrifugal action of the pin 5 and is allowed to escape from escape passages 47, 49. Because then the area of the left side passage 47 of the oil hole 15 is smaller than that of the right side passage 49, the amount of oil allowed to escape from the passage 47 is limited and distributed to the right side: ie. uniform oil films are formed on both sides of the pin 5 and also the area of each passage 47, 49 is set such that a proper amount of oil is fed to the oil passage 35 of a connecting rod 31, whereby lubricity will not be damaged even when the oil hole 15 is biased from the center portion of the pin 5.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to a bearing of a crankshaft in a shaft portion such as a crank bin or a crank journal of a crankshaft, particularly in a shaft portion in which a fillet portion is formed. Regarding structure.

(Prior Art) As shown in FIG. 6, a crankshaft 101 of a multi-cylinder internal combustion engine, etc., supports shaft portions (crank journals) 105 formed on both sides of a pair of crank arms 103 with bearings 111. A large end portion of a connecting rod 113 is supported on a shaft portion (crank pin) 107 between crank arms 103, 103. This figure is from the 1960s.
1-5451.5, the crankshaft 101 has an oil hole 109 that communicates from the center of the crank journal 105 to the center of the crank pin 1.07.
The lubricating oil that is pumped to the bearing 111 is supplied to the support portion of the connecting rod 11-3 through the oil hole 109. In general, the crank journal 1.05 and the crank pin 107 have fillet portions 1.05 and 1.05 each having a small fillet radius at both shaft ends.
06 and 108 are formed to relieve stress concentration on these shaft ends.

However, in such conventional crankshafts, it is not possible to completely eliminate the stress concentration at the shaft end, so it is necessary to reduce the stress in the entire shaft. Crankbin 10 that receives heavy loads
7 had to be made larger in diameter. Well, as a solution to this difficulty,
No. 92210 or Japanese Utility Model Application No. 61-9620 discloses a rank shaft as shown in FIG.

In this crankshaft 1, a crank journal 3 is supported by a bearing metal 23 of a bearing 21 in the same manner as in the above-mentioned conventional crankshaft, and this supporting portion has an oil passage 25.
Lubricating oil is pumped through. crankshaft 1
The crank bin 5 has a minimum diameter at the center in the axial direction, and extends from the center to both shaft ends, that is, the inner surface 11. of the crank arm 9. ．． A series of fillets 7.7 having a large fillet radius are formed over the crankshaft 11, so that the crank bin 5 as a whole has a block-like shape. A bearing metal 33 is attached to the large end of the connecting rod 31, following the shape of this hook-shaped shaft and enclosing it. An oil passage 35 is formed for guiding lubricating oil to the part.

According to such a chain-shaped crankbin, the stress is dispersed and decreased as it approaches the ends of both shafts, so the shaft diameter at the center is set to the minimum dimension that can withstand bending and torsional loads. Even if set to , damage caused by the stress concentration can be avoided, and thereby the inertial mass of the crankshaft, connecting rod, etc. can be reduced.

Incidentally, such a shape of the shaft portion can also be applied to a crank journal (see the above-mentioned Japanese Utility Model Publication No. 619620).

(Problem to be Solved by the Invention) However, in such a conventional bearing structure, if an oil hole 109 is formed as shown in FIG. 6, the oil hole 109 will reduce the strength of the central part of the shaft. In order to compensate for this, there arises the disadvantage that the diameter of the scales must be made small and the central part of the scales must be enlarged.

The above-mentioned holes not only help improve the lubricity of the crankbin, but also work extremely effectively when lubricating oil is to be supplied to the small end through the oil passage 35 of the connecting rod as described above.

Therefore, an object of the present invention is to form oil holes without reducing the load-bearing strength of the shaft portion.

[Structure of the invention]

(Means for Solving the Problems) The means of the present invention for solving the problems described above includes a shaft portion in which fillets are formed from the central portion in the axial direction to both shaft end portions, and this shaft portion. In the bearing structure of a crankshaft, the shaft part has an oil hole that penetrates near the shaft end on one side and opens at both shaft ends from the inner surface of the bearing to the shaft end. An oil relief passage leading to the outside is formed, and the passage area of the relief passage is set to be small on one side and large on the other side.

According to this method, near the end of the shaft on one side through which the oil hole penetrates, there is a region where a fillet with a large fillet radius cannot be formed, and here stress is dispersed and reduced as described above. Therefore, even if an oil hole is formed here, the load-bearing strength of the shaft portion will not be reduced. Also, as a result of this, the oil hole opens biased to one side, but the passage area of the relief passage is made smaller on one side.
Since the other side is set larger, a larger relief resistance is applied to this side, so by appropriately distributing these passage areas, it is possible to spread the lubricating oil over the entire shaft part. can.

(Embodiment) An embodiment of the present invention will be described with reference to FIGS. 1 to 3.

This embodiment is basically constructed on the basis of the one shown in FIG. 5, and the same reference numerals as used in FIG. 5 are given to parts having the same functions, so that redundant explanation will be omitted.

A large end of a connecting rod 31 equipped with a bearing metal 37 according to this embodiment is supported on the crank pin 5, which is a chain-shaped shaft that spans between the crank arms 9 and 9 of the crankshaft 1. There is. As shown in an enlarged view in FIG. 3, the bearing metal 37 includes a metal body 39 that encloses the pin 5 along the crank bin 5;
Thrust flanges 41 formed on both sides of the metal body 39
141. The outer surface of the thrust flange 41 faces the inner surfaces 11.11 of the crank arms 9, 9 with a slight gap e between them, and a plurality of oil grooves 43 and 45 are formed in these opposing parts as shown in FIG. radially as shown,
It is formed from the inside of the metal body 39 to the outer periphery of the thrust flange 41. Oil groove 43.45 and the above gap e
Accordingly, oil relief passages 47 and 49 are formed on the left and right sides of the crank bin 5 in the drawing, respectively. Further, the connecting rod 31 is formed with an oil passage 35 for guiding lubricating oil from the center of the crank bin 5 to the small end of the rod 31.

On the other hand, the bearing 21 that supports the crank journal 3 includes an oil passage 25 for pumping lubricating oil to the center of the bearing. The crankshaft 1 is formed with an oil hole 15 which penetrates from the center of the left crank journal 3 toward the left shaft end of the crank bin 5 and opens into the left fillet 7. A communication hole 17 is formed in the crank bin 5 and communicates from the opening of the oil hole 15 to the fillet 7 to the opposite side of the crank bin 5. The total cross-sectional area of the oil groove 43 is set smaller than that of the oil groove 45, thereby making the passage area of the left side relief passage 47 smaller than that of the right side relief passage 49.

The area of these passages is determined by the oil groove 43.4 as shown in Figure 3.
In addition to varying the depth of grooves 5, by varying the width or number of grooves, an appropriate relationship as described below can be set.
Alternatively, the oil groove 43 can be eliminated and this left side relief passage can be connected to the gap e.
It can also be formed by only a portion.

The embodiment is configured as described above. Next, the effect will be explained.

The oil hole 15 is located in the fillet 7 near the left shaft end of the crank bin 5.
This penetration part has a small internal stress, so even if the strength of the fillet part 7 decreases due to the formation of the oil hole 15, it will not affect the load-bearing strength of the entire crankbin 5, especially the central part. As mentioned above, it is not given. The same applies to the communication hole 17.

On the other hand, the lubricating oil that has been pressure-fed through the oil passage 25 of the bearing 21 is diverted to the oil hole 15 by the rotation of the crank journal 3, and then is discharged toward the left shaft end of the chain-shaped crank bin 5. Furthermore, the flow is branched to the communication hole] 7 and is also fed to the opposite side of the crank bin 5. These lubricating oils flow between the bearing metal 37 and the relief passage 47.4 while being subjected to centrifugal action due to the rotation of the crank bin 5.
Escape from 9. At this time, since the passage area of the left side relief passage 47 near the opening of the oil hole 15 is set smaller than the passage area of the right side relief passage 49 far from this opening, the escape from the relief passage 47 is more restricted. and the amount is distributed to the right side. In other words, the left and right relief passages 47 and 49 are arranged so that an almost even oil film is formed on both left and right sides of the crank bin 5 and an appropriate amount of lubricating oil is fed to the oil passage 35 of the connecting rod 31. The area of the passage is set. As a result, even though the oil hole 15 is formed offset from the center of the crankshaft crankshaft 5, the lubricity is not impaired.

FIG. 4 shows an embodiment in which the present invention is applied to a crank journal.

The crank journal 53 is supported by a bearing 55 and has a helical shape with fillets 54 and 54 extending from its center to both shaft ends (the outer surfaces 13 and 13 of the crank arm 9). . bearing 55
is equipped with an oil passage 57 for pumping lubricating oil to the center of the journal 53, and both left and right sides of the oil passage 57 are connected to the crank arm 9,
They face the outer side surfaces 13, 1.3 of 9 with gaps 1B, e2 therebetween, respectively, and five left and right relief passages 61 are formed by these gaps. An oil hole 15 penetrating into the crank bottle is formed near the right shaft end of the crank journal 53, and correspondingly, the gap g2 in the right relief passage 61 is set smaller than the gap e+ in the left relief passage 59. It is.

Therefore, when lubricating oil is pumped from the oil passage 57,
This flows to the left and right and flows between the crank journal 53 and the bearing 55, and the left and right relief passages 59.6
deviate from 1. At this time, since the sizes of the left and right gaps I1.12 are set as described above, the right side relief passage 6
1, a larger flow resistance is imparted. As a result, the amount of lubricating oil that has been diverted to the right side is restricted and flows into the oil hole 15. That is, the gap (B
, 12.

〔Effect of the invention〕

As described above, in a crankshaft bearing structure in which an oil hole is formed in a shaft portion in which a large fillet is formed from the central portion in the axial direction to both shaft end portions, the oil hole Since the shaft is provided through the fillet where internal stress is small, strength is guaranteed without expanding the diameter of the shaft. Also, this moves the opening of the oil hole from the center to one side (-), but this - left side has greater resistance to oil release, making it easier to spread the lubricating oil over the entire shaft. The invention therefore makes it possible to open oil holes without compromising the advantages possessed by this type of crankshaft.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view of a bearing according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, Fig. 3 is an enlarged view of the main part of Fig. 1, and Fig. 4 is 5 and 6 are side sectional views of a bearing section showing an embodiment in which the present invention is applied to another shaft section.
Each figure is a side sectional view of a bearing part according to a conventional example. 1. ... Crankshaft 5. ... Crankbin (shaft) 7.
・Fillet 15... ・Oil hole 37・φ Repair bearing metal 4.7.49 ・ 53 ・ 54 ・ 55 φ 59, 61 ・・Oil release passage・Crank journal・Fillet・Bearing・Oil Relief passage (shaft)

Claims (1)

[Claims] In a crankshaft bearing structure that includes a shaft portion in which a fillet is formed from the center in the axial direction to both shaft ends, and a bearing that encloses this shaft portion, the shaft portion is located near one shaft end. It has an oil hole that opens through the bearing, and an oil relief passage leading from the inner surface of the bearing to the outside of the shaft end is formed at both shaft ends, and the passage area of the relief passage is small on one side and on the other side. The crankshaft bearing structure is characterized by a large size on the side.