JP5342634B2 - Crankshaft lubrication structure for engines - Google Patents

Description

  The present invention relates to an oil supply structure of a crankshaft in an engine, in particular, a crankshaft having a plurality of journal portions and a plurality of crankpins, and an engine body having a plurality of bearing surfaces for supporting each journal portion of the crankshaft. The engine body is provided with a plurality of main body oil supply passages for individually supplying oil to a plurality of journal portions, and a common oil supply source is connected in parallel to the main body oil supply passages. The cylindrical bearing metal that rotatably fits and supports the outer peripheral surface of the corresponding journal portion is fitted and fixed, and each bearing metal is connected to the corresponding main body oil supply passage and is connected to the bearing metal. The present invention relates to an oil supply structure in which a plurality of communication holes penetrating a metal in a radial direction are formed side by side in a circumferential direction.

  In the crankshaft oil supply structure described above, a plurality of journal portions communicates with an in-shaft oil passage for supplying a part of the supply oil from the main body oil passage to the crankpin, and the in-shaft oil passage The second main body oil supply passage that supplies oil to the second journal portion among the plurality of main body oil supply passages is more oiled than the first main body oil supply passage that supplies oil to the first journal portion. There is known one provided with oil supply amount limiting means for reducing the amount (see Patent Document 1 below).

JP 2008-196396 A

  In the conventional structure disclosed in Patent Document 1, the amount of oil supplied to the second journal portion that does not require oil supply to the crank pin is limited to the amount of oil supplied to the second main body oil supply passage corresponding to the second journal portion. By means of this, the amount of oil supplied to the first journal part that needs to be supplied to the crank pin is narrowed down, whereby oil is distributed to each journal part according to the required oil supply amount of these journal parts, and the oil supply source The size and capacity of the engine and the output loss of the engine are reduced.

  However, in this conventional structure, when the oil supply amount limiting means is provided, a special part that exhibits an orifice function is mounted in the middle of the second main body oil supply path of the engine main body, or a special purpose corresponding to the second journal portion is provided. As the bearing metal, the one that can exhibit the throttling function by reducing the diameter of the communication hole is specially used, so the number of parts increases and the cost increases, or multiple journal parts It is necessary to use different bearing metals according to the required amount of lubrication.

  The present invention has been proposed in view of the above, and an object thereof is to provide an oil supply structure for a crankshaft in an engine that can solve the above-described conventional problems with a simple structure.

  In order to achieve the above object, an invention according to claim 1 is directed to an engine body having a crankshaft having a plurality of journal portions and a plurality of crankpins, and a plurality of bearing surfaces for supporting each journal portion of the crankshaft. The engine body is formed with a plurality of body oil supply passages for individually supplying oil to the plurality of journal portions, and a common oil supply source is connected in parallel to the body oil supply passages, A cylindrical bearing metal that rotatably fits and supports the outer peripheral surface of the corresponding journal portion is fitted and fixed to the bearing surface of each of the bearing surfaces, and each bearing metal is connected to the corresponding main body oil supply passage. And a plurality of communication holes that penetrate the bearing metal in the radial direction are formed side by side in the circumferential direction, and the plurality of journal portions are formed in the crankshaft to supply oil to the crankpin. The second main body oil supply passage that is divided into a first journal portion that communicates with the road and a second journal portion that does not communicate with the in-shaft oil passage, and supplies oil to the second journal portion among the plurality of main body oil supply passages. In an oil supply structure for a crankshaft in an engine, provided with an oil supply amount limiting means for reducing an oil supply amount compared to a first main body oil supply passage for supplying oil to the first journal portion, the first main body oil supply passage is formed of the first journal portion. And a communication groove that is recessed in the bearing surface and extends in the circumferential direction of the bearing surface and communicates with the plurality of communication holes. A restriction oil passage that opens to the bearing surface for supporting a portion and communicates only with a part of the plurality of communication holes, and the restriction oil passage includes the oil supply amount restriction means. It is characterized by comprising.

  In addition to the feature of the invention of claim 1, the invention of claim 2 is characterized in that the inner diameters of at least two of the plurality of communication holes are set to be different from each other.

  According to a third aspect of the present invention, in addition to the features of the first or second aspect of the invention, the bearing metal may be disposed after the rotational direction of the crankshaft as viewed from a portion receiving the maximum load from the journal portion during an engine explosion stroke. The part of the communication holes are formed in the half-circumferential portion on the side.

  According to the present invention, the first main body oiling passage corresponding to the first journal portion that requires oil supply to the crankpin and requires a large amount of oil supply is recessed in the bearing surface for supporting the first journal portion and It has a communication groove that extends in the circumferential direction of the bearing surface and communicates with a plurality of communication holes in the bearing metal. On the other hand, there is no need for oil supply to the crankpin and it corresponds to the second journal part that requires less oil. The second main body oil supply passage has a restriction oil passage that opens to a bearing surface for supporting the second journal portion and communicates only with a part of the plurality of communication holes. Since the oil passage constitutes the oil supply amount limiting means, when providing the oil supply amount limiting means, a special part that exhibits an orifice function is specially attached to the second body oil supply passage as in the conventional structure, or the first and first 2 Using bearing metal in the journal Therefore, the number of parts can be reduced, the cost can be reduced, and the lubrication amount control to the first and second journal portions can be appropriately performed while avoiding the complicated assembly work. it can.

  In particular, according to the invention of claim 2, since the inner diameters of at least two communication holes of the plurality of communication holes are set to be different from each other, the restriction oil passage is set according to a required oil supply amount in each journal portion. By changing the shape and opening position, it becomes possible to change the combination of the communication holes that communicate with the restricted oil passage, so that adjustment of the amount of oil restricted by the oil amount restricting means (restricted oil passage) can be made easier and It can be done in various ways.

  In particular, according to the invention of claim 3, the bearing metal includes the part of the communication hole in a half circumference on the rear side in the rotation direction of the crankshaft as viewed from a portion that receives the maximum load from the journal part in the explosion stroke of the engine. In the second journal portion, the part of the communication holes is formed in the second journal portion immediately before the maximum load is generated, with respect to the semicircular portion on the rear side in the rotation direction of the second journal portion as viewed from the portion receiving the maximum load. Through this, oil can be supplied efficiently. Accordingly, even if the second journal portion is supplied with oil only from the part of the communication holes via the restricted oil passage, a necessary and sufficient amount of lubricating oil for the second journal can be secured, and a sliding portion such as a bearing metal can be secured. It is possible to prevent a decrease in durability.

1 is a longitudinal sectional view of an essential part of an engine according to an embodiment of the present invention. Enlarged cross-sectional view of the first journal part and its periphery (enlarged cross-sectional view taken along line 2-2 in FIG. 1) 3-3 sectional view of FIG. Enlarged cross-sectional view of the second journal part and its surroundings (enlarged cross-sectional view taken along line 4-4 in FIG. 1) It is explanatory drawing which exaggerated and drawn the sliding gap between a bearing metal and a 2nd journal part, and the flow of the oil supply from the 2nd main body oil supply path to the 2nd journal part side, (A) is just before an explosion stroke. State, and (B) shows the state during the explosion process.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  An engine main body EB of a multi-cylinder engine E mounted on a vehicle includes a cylinder block 1 having a plurality (four in the illustrated example) of cylinders 1a arranged in parallel with each other, and a cylinder head (see FIG. And a lower block 2 and an oil pan 3 that are sequentially coupled to the lower part of the cylinder block 1. The crank chamber 4 is defined by the lower part of the cylinder block 1, the lower block 2 and the oil pan 3. Made.

  The crank chamber 4 accommodates a crankshaft CS that extends along the parallel direction of the cylinder 1a and is rotatably fitted to and supported by a plurality of bearing surfaces B1 and B2 of the engine body EB. An oil pump OP is disposed as an oil supply source that is driven by the shaft CS and pumps up the stored lubricating oil in the oil pan 3.

  The crankshaft CS is arranged adjacent to each other with a plurality of journal portions J1 and J2 that are arranged at intervals in the axial direction and are rotatably fitted and supported on the plurality of bearing surfaces B1 and B2 of the engine body EB. Each of the pair of crank webs 5 integrally extending radially outward from the journals J1 and J2 and a crank pin 6 integrally connecting the pair of crank webs 5 are provided. A large end portion of a connecting rod 10 connected to a piston 7 slidably fitted to the corresponding cylinder 1a is rotatably fitted and connected to each crank pin 6.

  A bearing wall 1b formed integrally with the lower half of the bearing surfaces B1 and B2 is formed at the lower portion of the cylinder block 1, and the lower half of the bearing surfaces B1 and B2 is formed on the lower surface of the bearing wall 1b. A bearing cap 8 having a portion formed on the upper surface is detachably fastened via a bolt (not shown).

  The engine main body EB (that is, each bearing wall 1b of the cylinder block 1) is formed with a plurality of main body oil supply paths P1, P2 for individually supplying the plurality of journal portions J1, J2, and these main body oil supply paths P1. , P2 are open to the upper half of the corresponding bearing surfaces B1, B2, respectively. Further, the upstream sides of the main body oil supply passages P1 and P2 are connected in parallel to the discharge side of the oil pump OP through an oil gallery 9 passing through the wall of the cylinder block 1 along the axis of the crankshaft CS. The

  A cylindrical bearing metal M that rotatably fits and supports the outer peripheral surface of the corresponding journal portion J1, J2 is fitted and fixed to each bearing surface B1, B2. The bearing metal M is formed by a semi-cylindrical upper metal half Mu fitted to the upper half of the bearing surfaces B1 and B2 formed by the bearing walls 1b of the cylinder block 1 and the bearing caps 8. And the lower metal half Ml having a semi-cylindrical shape fitted in close contact with the lower half of the bearing surfaces B1 and B2. In the state where the journal walls J1 and J2 and the upper and lower metal halves Mu and Ml are sandwiched between the bearing walls 1b and the bearing caps 8 of the cylinder block 1, the upper and lower metals The half bodies Mu and Ml are respectively fixed to the upper half portion and the lower half portion of the bearing surfaces B1 and B2 in a state in which the opposite ends of the two are in contact with each other.

  Each bearing metal M, in particular the upper metal half Mu, is arranged in parallel on the inner circumferential surface thereof with a groove g extending over the entire length in the circumferential direction and at a position corresponding to the groove g in the circumferential direction with a gap in the circumferential direction. In addition, a plurality of first to third communication holes H1 to H3 penetrating the upper metal half Mu in the radial direction are formed. As described later, the main body is formed in all or a part of the communication holes H1 to H3. The oil supply paths P1 and P2 communicate with each other.

  Further, at least two of the communication holes H1 to H3 are formed with different diameters, that is, in the illustrated example, the first and second communication holes H1 and H2 are formed with a large diameter and the same diameter, The third communication hole H3 is formed with a smaller diameter than the first and second communication holes H1 and H2 so as to exert a throttling effect on the flow of refueling.

  Further, each bearing metal M (upper metal half Mu) has a crankshaft as viewed from a portion X (see FIG. 5B) that receives the maximum load from each journal portion J1, J2 during the explosion stroke of the engine E. A third communication hole H3 is provided in the half circumference on the rear side in the rotation direction of the CS, and a first communication hole H1 is provided in the half circumference on the front side in the rotation direction. A second communication hole H2 is disposed on the opposite side across the axis.

  The structure of the bearing metal M described above is the same for the bearing metal mounted on any of the bearing surfaces B1 and B2 that support the crankshaft CS. Therefore, it is necessary to use a different bearing metal for each journal portion J1 and J2. Therefore, the number of parts can be reduced as much, and there is no risk of misassembly.

  By the way, all the journal parts J1 and J2 with which the crankshaft CS is provided have an in-shaft oil passage A formed inside the crankshaft CS in order to further feed a part of the lubricating oil supplied to the journal part to the crankpin 6. Are classified into a first journal portion J1 that communicates with the second journal portion J2 that does not communicate with the in-shaft oil passage A. That is, in the illustrated example, three journal portions located at both ends and the center in the axial direction of the crankshaft CS correspond to the second journal portion J2, and other journal portions (that is, adjacent second journal portions J2). The two journal parts sandwiched between them correspond to the first journal part J1.

  In the illustrated example, the in-shaft oil passage A has a transverse oil passage 11 that traverses the first journal portion J1 and both ends open to the outer peripheral surface of the first journal portion J1, and one end directly communicates with the transverse oil passage 11. The end is composed of a pair of vertical oil passages 12 that open to the outer peripheral surface of each of the crank pins 6 on one side and the other side in the axial direction of the first journal portion J1, and the outer peripheral surface of the first journal portion J1 The guide groove 13 that is continuous with the opening at both ends of the lateral oil passage 11 is recessed.

  Each vertical oil passage 12 includes a first oil passage 12a that is drilled in a straight line across the first journal portion J1, the crank web 5 and the crank pin 6 with a drill or the like, and the first oil passage 12 12a, a second oil passage 12b branched from the middle of the crank pin 6 and opened to the outer peripheral surface of the crankpin 6. The opening end of the first oil passage 12a to the crank web 5 is a stopper fixed thereto later. It is blocked by the body 13.

  All of the main body oil supply paths P1 and P2 included in the engine main body EB include a first main body oil supply path P1 for supplying oil to the first journal portion J1 (and thus also to the crankpin 6 via the first journal portion J1), 2 is classified into a second main body oil supply path P2 for supplying oil to the journal portion J2. Therefore, it is only necessary to supply the second main body oil supply path P2 with oil necessary to lubricate the corresponding second journal portion J2, and a part of the lubricating oil supplied to the second journal portion J2 is crankpin. Since it is not necessary to supply oil to the 6th side, the required oil supply amount of the second main body oil supply path P2 may be relatively smaller than that of the first main body oil supply path P1. Therefore, in this embodiment, in order to balance the oil supply to the first and second main body oil supply paths P1, P2 having different required oil supply quantities, the oil supply quantity is made smaller than that of the first main body oil supply path P1, as will be described later. An oil supply amount limiting means 21 is provided in the second main body oil supply path P2.

  Thus, the first main body oil supply passage P1 is recessed in the first bearing surface B1 corresponding to the first journal portion J1 and extends in the circumferential direction of the first bearing surface B1 to extend the first to third of the metal bearing M. A communication groove 20 communicating with all the communication holes H1 to H3 is provided at the downstream end.

  On the other hand, the second main body oil supply path P2 opens to the second bearing surface B2 corresponding to the second journal portion J2, and communicates only with a part of the communication holes (third communication hole H3 in the illustrated example) of the metal bearing M. A restriction oil passage 21 is provided at the downstream end, and the restriction oil passage 21 constitutes the oil supply amount restriction means. The restriction oil passage 21 is formed in a spherical surface having a diameter larger than the inner diameter of the second main body oil supply passage P2 in the illustrated example, and the opening surface of the second main body oil supply passage P2 to the second bearing surface B2 is enlarged. Only the third communication hole H3 of the first to third communication holes H1 to H3 faces the enlarged opening surface.

  Next, the operation of the embodiment will be described.

  In the operating state of the engine E, the oil pump OP driven by the crankshaft CS pumps up the lubricating oil in the oil pan 2 and continuously supplies oil to each lubricated portion in the engine. A part of the oil discharged from the oil pump OP is distributed and supplied to the first and second main body oil supply passages P1 and P2 through the oil gallery 9 in the wall of the cylinder block 1, and from there, the engine block EB Are supplied to the first and second journals J1 and J2 through the bearing metal M of the corresponding first and second bearing surfaces B1 and B2.

  In this case, as shown in FIG. 2, the lubricating oil flowing through the first main body oil supply path P1 is located at the downstream end of the first to third bearing metal M from the communication groove 20 that opens to the first bearing surface B1. It reaches the outer peripheral surface of the first journal portion J1 through the communication holes H1 to H3 and the concave groove g, lubricates the sliding gap between the outer peripheral surface and the inner peripheral surface of the bearing metal M, and further provides a lubricant oil. The portion flows into the lateral oil passage 11 of the in-shaft oil passage A through the guide groove 13 opened in the outer peripheral surface of the first journal portion J1, and from there through the vertical oil passage 12 of the in-shaft oil passage A, the crankpin 6 The sliding portion between the outer peripheral surface and the bearing surface of the connecting rod 10 large end is lubricated.

  On the other hand, as shown in FIG. 4, the lubricating oil flowing through the second main body oil supply passage P2 is located at the downstream end of the lubricating oil from the restriction oil passage 21 that opens to the second bearing surface B2, and the third communication hole H3 of the bearing metal M. In addition, it reaches the outer peripheral surface of the second journal portion J2 through the concave groove g, and lubricates the sliding gap between the outer peripheral surface and the inner peripheral surface of the bearing metal M. Thus, the downstream side of the second main body oil supply passage P2 communicates only with the relatively small third communication hole H3 of the bearing metal M through the restriction oil passage 21, and the second journal is connected to the communication portion. Since the amount of oil supplied to the part J2 is reduced, the amount of oil supplied to the first journal part J1 side from the first main body oil supply path P1 that does not receive such a restricting action is sufficiently suppressed.

  As described above, the first main body oil supply passage P1 corresponding to the first journal portion J1 that requires oil supply to the crankpin 6 and requires a large amount of oil supply is recessed in the first bearing surface B1 for supporting the first journal portion J1. And a long communication groove 20 that extends in the circumferential direction of the bearing surface B1 and communicates with all of the plurality of communication holes H1 to H3 of the bearing metal M. On the other hand, there is no need to supply the crankpin 6 with oil. The second main body oil supply passage P2 corresponding to the second journal portion J2 having a small required amount of oil supply opens to the second bearing surface B2 for supporting the second journal portion J2, and the plurality of communication holes H1 to H3 are provided. There is a restricted oil passage 21 that communicates with only a part (that is, the third communication hole H3), and the restricted oil passage 21 constitutes an oil supply amount restricting means. Accordingly, since the lubricating oil can be appropriately distributed to the journal portions J1 and J2 according to the required oil supply amounts of the first and second journal portions J1 and J2, it is possible to reduce the size of the oil pump OP as an oil supply source. A reduction in capacity and a reduction in engine output loss are achieved.

  In addition, when providing the oil supply amount limiting means, a special part that exhibits the orifice function is specially attached to the second main body oil supply path P2 as in the conventional structure, or the first and second journal parts J1 and J2 are used exclusively. Since there is no need to use different bearing metals, the number of parts can be reduced, cost can be reduced, and the amount of oil supplied to the first and second journal parts J1 and J2 can be controlled while avoiding complicated assembly work. Can be done appropriately. In addition, since the same bearing metal M can be used for all the journal portions J1, J2, there is no fear of misassembling the bearing metal M.

  In addition, in the present embodiment, the inner diameters of at least two communication holes (H1, H2, and H3 in the illustrated example) of the plurality of communication holes H1 to H3 formed in the bearing metal M are set to be different from each other. Yes. Therefore, a plurality of combinations of communication holes communicating with the restriction oil passage 21 can be changed only by changing the shape and opening position of the restriction oil passage 21 in accordance with the required oil supply amount in each journal portion J1, J2. Therefore, the oil supply amount restricted by the oil supply amount limiting means (restricted oil passage 21) can be adjusted more easily and variously.

  Further, in the present embodiment, the bearing metal M includes a rotation direction of the crankshaft CS as seen from the portion X that receives the maximum load from the journal portions J1 and J2 in the explosion stroke of the engine E as shown in FIG. Since the third communication hole H3 is arranged in the rear half circumference, particularly in the second journal J2, the maximum load is received immediately before the maximum load is generated (see FIG. 5A). The oil can be efficiently supplied through the third communication hole H3 to the semicircular portion on the rear side in the rotation direction of the second journal portion J2 when viewed from the portion X. Accordingly, since the second journal portion J2 is supplied with oil only from the third communication hole H3, the required amount of lubricating oil for the second journal J2 can be secured even if the amount of oil supply is relatively small. It is possible to prevent the durability of the sliding part such as M from being lowered. Further, since it is possible to further reduce the amount of oil supplied to the second journal portion J2, it is possible to further contribute to downsizing of the oil pump OP and reduction of output loss of the engine.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. Is possible.

  For example, in the above embodiment, the present invention is applied to an in-line four-cylinder engine. However, the present invention can be applied to an in-line multi-cylinder engine having a plurality of cylinders other than four cylinders and a multi-cylinder V-type engine. is there. The engine type may be a 4-cycle engine or a 2-cycle engine, and may be a gasoline engine or a diesel engine.

  Further, the form of the communication groove 20 which is present at the downstream end of the first main body oil supply path P1 and communicates with the plurality of communication holes H1 to H3 of the bearing metal M at the same time is not limited to that of the above-described embodiment. Various variations can be adopted as long as the grooves are in communication with the communication holes H1 to H3 and open to the first bearing surface B1.

  Moreover, the form of the limiting oil passage 21 which exists at the downstream end of the second main body oil supply passage P2 and communicates only with a part of the plurality of communication holes H1 to H3 of the bearing metal M is the same as that of the above embodiment. The present invention is not limited to the above, and various variations can be adopted as long as the passage form communicates with only a part of the communication holes and opens to the second bearing surface B2.

  Further, in the above embodiment, the restriction oil passage 21 is communicated only to the single communication hole H3. However, in the present invention, depending on the required oil supply amount of the second journal portion J2, a plurality of restriction oil passages (however, the communication holes are provided). You may make it communicate with a communicating hole of a number smaller than the total number of.

A ····· Intra-shaft oil passages B1, B2 ··· First and second bearing surfaces CS ··· Crankshaft E ··· Engine EB ··· Engine as engine body Blocks H1 to H3 .. First to third communication holes J1, J2... First and second journal portions M... Bearing metal OP ... Oil pumps P1 and P2 as oil supply sources・ ・ First and second body oil supply passage X ・ ・ ・ ・ ・ ・ Part 6 where the bearing surface receives the maximum load from the second journal during the engine explosion stroke ・ ・ ・ ・ ・ ・ Crank pin 20 ・ Communication Groove 21... Restricted oil passage as means for limiting the amount of oil supplied

Claims (3)

Crankshaft (CS) having a plurality of journal portions (J1, J2) and a plurality of crankpins (6), and a plurality of bearing surfaces for supporting each journal portion (J1, J2) of the crankshaft (CS) An engine main body (EB) having (B1, B2), and the engine main body (EB) includes a plurality of main body oil supply paths (P1, P2) for individually supplying oil to the plurality of journal portions (J1, J2). P2) is formed, and a common oil supply source (OP) is connected in parallel to the main body oil supply passages (P1, P2), and each bearing surface (B1, B2) has a corresponding journal portion (J1). , J2) is fitted and fixed to a cylindrical bearing metal (M) that rotatably fits and supports the outer peripheral surface of the outer peripheral surface, and each of the bearing metals (M) has a corresponding main body oiling path (P1, P2). P2) and the bearing A plurality of communication holes (H1 to H3) penetrating the tall (M) in the radial direction are formed side by side in the circumferential direction, and the plurality of journal portions (J1, J2) are to supply oil to the crankpin (6). The first journal portion (J1) that communicates with the in-shaft oil passage (A) formed in the crankshaft (CS) and the second journal portion (J2) that does not communicate with the in-shaft oil passage (A). Of the plurality of main body oil supply paths (P1, P2), the second main body oil supply path (P2) for supplying oil to the second journal section (J2) has a first main body oil supply path for supplying oil to the first journal section (J1). In the oil supply structure of the crankshaft in the engine, provided with an oil supply amount limiting means (21) for reducing the oil supply amount than (P1),
The first main body oil supply passage (P1) is recessed in the bearing surface (B1) for supporting the first journal portion (J1) and extends in a circumferential direction of the bearing surface (B1), so A communication groove (20) communicating with the communication holes (H1 to H3);
The second main body oil supply passage (P2) opens to the bearing surface (B2) for supporting the second journal portion (J2) and is a part of the plurality of communication holes (H1 to H3). An oil supply structure for a crankshaft in an engine, comprising a restriction oil passage (21) communicating only with the communication hole (H3), and the restriction oil passage (21) constitutes the oil supply amount restriction means. .   2. The crankshaft of the engine according to claim 1, wherein inner diameters of at least two communication holes (H1, H2; H3) of the plurality of communication holes (H1 to H3) are set to be different from each other. Oiling structure.   In the bearing metal (M), in the half circumference on the rear side in the rotation direction of the crankshaft (CS) as viewed from the portion (X) receiving the maximum load from the journal portion (J1, J2) in the explosion stroke of the engine, The oil supply structure for a crankshaft in an engine according to claim 1 or 2, wherein a part of the communication holes (H3) is formed.

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