Lubrication flow path structure for internal combustion engines

Abstract

To provide a lubrication passage structure of an internal combustion engine which can avoid mixing of chips which contributes to malfunction of a crank shaft even if limitations are imposed on a fastening position and a lubricating liquid supply position.SOLUTION: A lubrication passage structure 10 of an internal combustion engine E includes: a first housing (a crank case 14) which houses a crank shaft 22 having a journal part 22a therein; a second housing (a mono-block 12) which is connected to an upper part of the first housing and houses multiple cylinders therein; a main passage 20 which is provided corresponding to an extension direction of the crank shaft 22 in the second housing and in which a lubricating liquid to be supplied to the journal part 22a may circulate; a subsidiary passage 28 which allows the main passage 20 and the journal part 22a to communicate with each other and supplies the lubricating liquid to the journal part 22a; and a fastening hole 26 into which a fastening member 24 for fastening the crank case 14 to the second housing may be inserted. The subsidiary passage 28 and the fastening hole 26 are provided at positions where they do not overlap each other on the same cross sectional surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lubrication passage structure for an internal combustion engine. [Background technology]

[0002] 2. Description of the Related Art In a conventional internal combustion engine, a crank cap is attached below a cylinder block that houses a crankshaft, cylinders, etc., and supports a journal portion of the crankshaft.

[0003] For example, Patent Document 1 discloses a structure in which a crank cap is fastened to a cylinder block using bolts. It also discloses a lubricating fluid passage structure that passes through a crankcase, which is part of the cylinder block, and communicates with a main gallery. Lubricating fluid (lubricating oil) supplied from the main gallery is supplied to the journal portion of the crankshaft. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-55585 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, the crank cap supports the journal of the crankshaft, and in this case, it is believed that stable support can be achieved by setting the bolt positions (fastening hole positions) so that the bolts are fastened at approximately the center of the axial direction of the crankshaft. Also, it is believed that even lubrication of the journal can be achieved by positioning the flow path (oil passage) that supplies lubricating fluid to the journal at approximately the center of the axial direction of the crankshaft in the journal.

[0006] However, depending on the configuration of the internal combustion engine, the crankcase and the cylinder block may be separate components, and the crankcase may need to be fastened to the cylinder block together with the crank cap. In this case, the bolts may penetrate the crankcase and extend to the vicinity of the cylinders (bores) of the cylinder block. In this case, when considering the optimal fastening positions and lubricant supply positions as described above, the fastening holes for the bolts extending into the cylinder block may intersect with the lubricant supply path. In such cases, when the bolts are inserted or removed during assembly or disassembly for maintenance, chips adhering to the fastening holes or the like may get mixed into the oil path and reach the sliding position of the crankshaft, potentially causing malfunction.

[0007] The object of the present invention has been made in consideration of the above, and is to provide a lubrication flow path structure for an internal combustion engine that can avoid the inclusion of chips, which can be a cause of crankshaft malfunction, even if there are restrictions on the fastening position or the lubricating liquid supply position. [Means for solving the problem]

[0008] In order to achieve the above object, a lubrication flow path structure for an internal combustion engine according to an embodiment of the present invention includes a first housing that houses a crankshaft having a journal portion therein, and a lubrication flow path structure connected to an upper portion of the first housing, a head portion and a It houses multiple cylinders inside The block part is composed of The engine is provided with a second housing that houses a plurality of cylinders therein, a main flow path that is provided inside the second housing in a direction corresponding to the extension of the crankshaft and through which lubricating liquid to be supplied to the journal portion can flow, a sub-flow path that connects the main flow path to the journal portion and supplies the lubricating liquid to the journal portion, and a fastening hole through which a fastening member that fastens the first housing and the second housing can be inserted, and the sub-flow path and the fastening hole are provided at non-overlapping positions on the same cross section. a tip end of the fastening hole is disposed in the block portion, an inlet of the sub-flow passage is connected to the main flow passage, and an outlet of the sub-flow passage is connected to the journal portion below the tip end and in the first housing. There are.

[0009] According to this configuration, for example, the secondary passage and the fastening hole can be completely separated, which prevents chips from getting into the secondary passage and journal portion and suppresses malfunctions of the crankshaft.

[0010] Further, the main flow path of the lubrication flow path structure of the internal combustion engine according to the embodiment of the present invention may be, for example, The aforementioned Tip Department It may be positioned higher.

[0011] This configuration, for example, can easily prevent the sub-flow passage from intersecting with the fastening hole, and the main flow passage is positioned higher on the second housing, which facilitates smoother supply of lubricating fluid to the journal.

[0012] Furthermore, the main flow path of the lubrication flow path structure of the internal combustion engine according to an embodiment of the present invention may be positioned, for example, between the outer wall surface of the second housing and the side surface of the cylinder, at a position biased toward the side surface.

[0013] According to this configuration, for example, the outlets of the main flow path and the secondary flow path (the connection portion with the journal portion) can be brought closer together in the radial direction of the cylinder, which makes it easier to contribute to reducing the size of the internal combustion engine in the radial direction of the cylinder. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a lubrication flow path structure for an internal combustion engine that can avoid the inclusion of chips, which can be a cause of crankshaft malfunction, even if there are restrictions on the fastening position or the lubricating liquid supply position. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is an exemplary schematic cross-sectional view showing a lubrication flow path structure of an internal combustion engine according to an embodiment. [Figure 2] FIG. 2 is an exemplary schematic diagram of the lubrication flow path structure of the internal combustion engine of FIG. 1 as viewed from the Y direction. [Figure 3]FIG. 3 is an exemplary schematic top view of the lubrication flow path structure of the internal combustion engine of FIG. 1 as viewed from the Z direction. DETAILED DESCRIPTION OF THE INVENTION

[0016] Exemplary embodiments of the present invention are disclosed below. The configurations of the embodiments described below, as well as the actions, results, and advantages brought about by the configurations, are merely examples. The present invention can be realized by configurations other than those disclosed in the following embodiments, and it is possible to obtain at least one of the various advantages based on the basic configurations and derivative advantages.

[0017] FIG. 1 is an exemplary schematic cross-sectional view showing a lubrication flow path structure 10 of an internal combustion engine E according to an embodiment of the present invention.

[0018] For convenience, the X-axis, Y-axis, and Z-axis are defined in this specification. The X-axis, Y-axis, and Z-axis are perpendicular to one another. The X-axis is set along the front-rear direction of the internal combustion engine E. The Y-axis is set along the width direction of the internal combustion engine E. The Z-axis is set along the height of the internal combustion engine E. Furthermore, the X-direction, Y-direction, and Z-direction are defined in this specification. The X-direction is the direction along the X-axis, the Y-direction is the direction along the Y-axis, and the Z-direction is the direction along the Z-axis.

[0019] The internal combustion engine E is, for example, a monoblock engine, and includes, for example, a monoblock 12 (sometimes referred to as a second housing), a crankcase 14 (sometimes referred to as a first housing), and a crank cap 16.

[0020] The monoblock 12 is a die-cast aluminum component in which a cylinder head and a cylinder block are integrated. The monoblock 12 is provided with a plurality of bores 18 in the X direction to form cylinders (to accommodate a plurality of cylinders inside). The monoblock 12 is also provided with a main passage 20 (main gallery) that corresponds to (is aligned with) the extension direction (X direction) of a crankshaft 22, for example, for supplying lubricating fluid (e.g., oil) that lubricates the driving parts of the internal combustion engine E to each position in the internal combustion engine E. The position where the main passage 20 is formed in the monoblock 12 will be described later. Also, in FIG. 1, only the lower region of the monoblock 12 is shown, and the upper region including the cylinder head, etc. is not shown.

[0021] The crankcase 14 is a box-shaped component that houses the crankshaft 22. Like the monoblock 12, the crankcase 14 is a component made, for example, from die-cast aluminum. The crankcase 14 has an upper bearing portion 14a, which is the upper half of a journal bearing B that supports the journal portion 22a of the crankshaft 22. The upper bearing portion 14a is, for example, a half-type plain bearing.

[0022] The crank cap 16 has, on its inner surface, a lower bearing portion 16a which is the lower half of a journal bearing B that supports a journal portion 22a of the crankshaft 22. The lower bearing portion 16a is a half-type plain bearing that forms a pair with the upper bearing portion 14a.

[0023] The crank cap 16 is formed with a fastening hole 26 for a fastening member 24 (e.g., a bolt) that penetrates in the Z direction. The fastening hole 26 further penetrates the crankcase 14 in the Z direction and reaches the monoblock 12. The fastening hole 26 that penetrates the crank cap 16 and the crankcase 14 is a hole that does not have a threaded portion. On the other hand, the fastening hole 26 formed in the monoblock 12 is Fastening member 24The crank cap 16 has a female thread portion 26a that meshes with the male thread portion of the crankshaft 22. Therefore, with the monoblock 12 placed on top of the crankcase 14 in a state in which the journal portion 22a of the crankshaft 22 is supported by the crank cap 16, the crankcase 14 can be fastened together using the fastening member 24. In other words, the crank cap 16 can rotatably fix the crankshaft 22 to the crankcase 14 by clamping and fastening the journal portion 22a between the upper bearing portion 14a and the lower bearing portion 16a. Note that in the example shown in FIG. 1, the fastening members 24 (fastening holes 26) are arranged in two locations symmetrically in the radial direction (Y direction) across the journal portion 22a.

[0024] The journal bearing B, which is composed of the upper bearing portion 14a and the lower bearing portion 16a, has the function of rotatably supporting the journal portion 22a of the crankshaft 22 as described above, as well as the function of supplying lubricating liquid to the journal portion 22a. For example, a lubricating liquid supply port 14b is formed in a portion of the upper bearing portion 14a. The supply port 14b is connected to the main flow path 20 formed in the monoblock 12 via a sub-flow path 28 (first portion 28a, second portion 28b). The lubricating liquid supplied to the journal bearing B from the supply port 14b, which is connected to the end of the sub-flow path 28 (second portion 28b), fills the circumferential direction along grooves formed on the inner surface of the journal bearing B, and lubricates the journal portion 22a.

[0025] In addition, the sub-flow passages 28 are provided in relation to the main flow passage 20 in a number corresponding to the number of journal portions 22a formed on the crankshaft 22, connecting the main flow passage 20 with each journal portion 22a so that lubricating fluid can be supplied to each journal portion 22a.

[0026] FIG. 2 is an exemplary schematic diagram of the lubrication passage structure 10 of the internal combustion engine E of FIG. 1 as viewed from the Y direction.

[0027] As shown in FIG. 2 , the crankshaft 22 includes a journal portion 22a, a crankpin 30, a crankarm 32, a balance weight 34, and the like. The crankpin 30 is connected to a piston (not shown) disposed inside the bore 18 via a connecting rod (not shown). The crankpin 30 and journal portion 22a are connected by the crankarm 32. A balance weight 34 is attached to the side of the crankarm 32 opposite to the side to which the crankpin 30 is connected, in order to reduce the inertial force generated by the movement of the piston and the connecting rod. The journal portion 22a and the crankpin 30 are connected to each other by a communication passage formed therein, so that the surfaces of the journal portion 22a and the crankpin 30 communicate with each other. Lubricating fluid supplied to the journal portion 22a is also supplied to the surface of the crankpin 30 via the communication passage, lubricating the contact area between the crankpin 30 and the connecting rod.

[0028] The crankshaft 22 configured as described above rotates at high speed. Therefore, ensuring the support rigidity of the crankshaft 22 contributes to reducing noise from the internal combustion engine E, improving the durability of the journal bearing B, and reducing friction. In other words, when fastening the crank cap 16 to the crankcase 14, the two need to be fastened stably and firmly. Therefore, when supporting the crankshaft 22 with the crank cap 16, it is desirable to fasten the crankshaft 22 using a fastening member 24 at approximately the center of the axial direction (X direction) of the journal portion 22a, as shown in FIG. 2 . In other words, it is desirable to set the position of a fastening hole 26 into which the fastening member 24 is inserted to be approximately the center of the axial direction of the journal portion 22a. Similarly, to ensure that the lubricating fluid that lubricates the journal portion 22a is supplied evenly in the axial direction (X direction) of the journal portion 22a, it is desirable to position the end 28c of the sub-flow passage 28 (second portion 28b) approximately at the center of the axial direction (X direction) of the journal portion 22a and connect it to the supply port 14b of the journal bearing B.

[0029] As described above, when the fastening hole 26 and the end 28c of the secondary flow passage 28 are positioned approximately in the center of the journal portion 22a, the fastening hole 26 and the secondary flow passage 28 are positioned on the same cross section, as shown in Fig. 1. In this case, if the fastening hole 26 and the secondary flow passage 28 intersect, chips adhering to the fastening hole 26 or the fastening member 24 may become mixed with the lubricating fluid flowing through the secondary flow passage 28 and reach the journal portion 22a or the crankpin 30 via the journal bearing B, potentially causing malfunction. Note that chips may include chips left over from the processing of the monoblock 12 or the crankcase 14, or chips generated when inserting or removing the fastening member 24 during assembly or maintenance of the internal combustion engine E.

[0030] Therefore, in the lubrication passage structure 10 of the internal combustion engine E according to the embodiment, as shown in FIG. 1, the secondary passage 28 and the fastening hole 26 are provided in non-overlapping positions (positions where they do not overlap) on the same cross section. For example, the main passage 20 connected to the secondary passage 28 is formed to be located above the tip 26b (tip position) of the fastening hole 26 in the monoblock 12 (second housing). In the case of FIG. 1, the secondary passage 28 connected to the main passage 20 formed in a position diagonally above the tip 26b (a position slightly away from the bore 18 in the -Y direction) is composed of a first portion 28a and a second portion 28b. For example, the first portion 28a extends from the main passage 20 in the Y direction and is connected to the second portion 28b toward the crankcase 14 below at a position spaced apart in the Z direction from and beyond the tip 26b of the fastening hole 26 in the Y direction. An end portion 28c connected to the supply port 14b is formed at the tip of the second portion 28b. In the case of Figure 1, the second portion 28b is bent midway, but the piping route can be selected appropriately as long as the secondary flow path 28 passes through a position above the tip 26b of the fastening hole 26. For example, the first portion 28a may extend to a position directly above the supply port 14b, and the second portion 28b may extend vertically downward.

[0031] By forming the positional relationship between the fastening holes 26 and the secondary flow passage 28 in this manner, even when the secondary flow passage 28 and the fastening holes 26 are arranged on the same cross section to provide stable, strong support for the journal portion 22a and good lubrication, as described above, it is possible to prevent foreign matter such as chips adhering to the fastening holes 26 or the fastening members 24 from entering the secondary flow passage 28. As a result, it is possible to reduce the occurrence of malfunctions of the journal portion 22a (crankshaft 22). In addition, it is possible to reduce clogging of the secondary flow passage 28 and the like due to chips, which also contributes to suppressing poor lubrication. It is also possible to reduce the occurrence of seizure problems and other problems in the sliding portions of the crankshaft 22.

[0032] 1, by positioning the main flow passage 20 above the tip end 26b (tip position) of the fastening hole 26 in the monoblock 12 (second housing), the lubricating liquid can be branched into each sub-flow passage 28 at a higher position, thereby enabling smoother supply of lubricating liquid to the journal portion 22a. Furthermore, the main flow passage 20 and the fastening hole 26 can be positioned so that they can overlap in the Z direction on the cross section. In this case, the thickness between the main flow passage 20 and the tip end 26b can be set so that a predetermined strength (rigidity) is obtained between them, which can contribute to reducing the width of the internal combustion engine E (monoblock 12) in the Y direction.

[0033] FIG. 3 is an exemplary schematic top view of the lubrication passage structure 10 of the internal combustion engine E of FIG. 1, as viewed from the Z direction. As shown in FIGS. 1 and 3, the main passage 20 is disposed between the outer wall surface (not shown) of the monoblock 12 (second housing) in the -Y direction and the side surface 18a of the bore 18 (cylinder), at a position offset toward (close to) the side surface 18a. As shown in FIG. 3, the main passage 20 is desirably positioned as close as possible to the side surface 18a of the bore 18 as possible to ensure the strength (rigidity) required for the main passage 20 and the bore 18. In other words, it is desirably positioned close to the supply port 14b (end 28c) in the vertical direction (Z direction). Such an arrangement enables a design that contributes to reducing the size of the internal combustion engine E in the radial direction (Y direction) of the bore 18 (cylinder) while avoiding intersections between the secondary passages 28 and the fastening holes 26.

[0034] (Effects of this embodiment) As described above, the lubrication passage structure 10 of the internal combustion engine E according to this embodiment includes the crankcase 14 (first housing) that houses the crankshaft 22 having the journal portions 22a, the monoblock 12 (second housing) that is connected to the upper part of the crankcase 14 and houses a plurality of bores 18 (cylinders) therein, the main passage 20 that is provided inside the monoblock 12 in a direction corresponding to the extension of the crankshaft 22 and through which lubricating liquid to be supplied to the journal portions 22a can flow, the sub-passage 28 that connects the main passage 20 and the journal portions 22a and supplies lubricating liquid to the journal portions 22a, and the fastening holes 26 through which fastening members 24 that fasten the crankcase 14 and the monoblock 12 can be inserted. The sub-passage 28 and the fastening holes 26 are provided in non-overlapping positions on the same cross section. This allows, for example, the secondary passage 28 and the fastening hole 26 to be completely separated, thereby preventing chips and the like from getting into the secondary passage 28 and the journal portion 22a, and suppressing malfunctions of the crankshaft 22.

[0035] Furthermore, the main flow path 20 of the lubrication flow path structure 10 of the internal combustion engine E according to the embodiment of the present invention is located, for example, above the tip end 26b (tip end position) of the fastening hole 26 in the monoblock 12 (second housing). This provides a structure that easily prevents, for example, intersection of the sub-flow path 28 and the fastening hole 26. Furthermore, because the position of the main flow path 20 is set at a higher position in the monoblock 12, it becomes easier to more smoothly supply lubricating liquid to the journal portion 22a.

[0036] Furthermore, the main flow passage 20 of the lubrication flow passage structure 10 of the internal combustion engine E according to the embodiment of the present invention may be disposed, for example, between the outer wall surface of the monoblock 12 and the side surface 18a of the bore 18, at a position biased toward the side surface 18a. This makes it possible to bring the main flow passage 20 and the outlet of the sub-flow passage 28 (the supply port 14b, which is the connection portion with the journal portion 22a) closer to each other in the radial direction (Y direction) of the bore 18, which makes it easier to contribute to reducing the size of the internal combustion engine E in the radial direction of the bore 18.

[0037] In the above-described embodiment, an example was shown in which the monoblock 12 was mounted on top of the crankcase 14. In another embodiment, a cylinder block with a separate cylinder head may be mounted on top of the crankcase 14. In this case, the configuration of this embodiment is also applicable, and similar effects can be obtained. Furthermore, in this embodiment, the fastening member 24 fastens the crank cap 16, crankcase 14, and monoblock 12 together. However, the crank cap 16 may be fastened separately to the crankcase 14 while supporting the journal portion 22a. In this case, the fastening member 24 fastens the crankcase 14 and monoblock 12. In this case, the configuration of this embodiment is also applicable, and similar effects can be obtained.

[0038] Although the embodiments of the present invention have been described above, the above-described embodiments are presented as examples and are not intended to limit the scope of the present invention. This novel embodiment can be embodied in various other forms. Furthermore, various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. Furthermore, this embodiment is included within the scope and spirit of the invention, and is also included in the inventions and their equivalents described in the claims. [Explanation of symbols]

[0039] 10 Lubrication flow path structure 12 Monoblock (second enclosure) 14 Crankcase (first housing) 14b Supply port 16 Crank cap 18 Bore 18a side 20 Main channel 22 crankshaft 22a Journal Section 24 Fastening members 26 Fastening holes 26b Tip 28 Subchannel 28c end E. Internal combustion engine

Claims

1. a first housing that houses a crankshaft having a journal portion; a second housing connected to an upper portion of the first housing and including a head portion and a block portion formed integrally with the head portion and accommodating a plurality of cylinders therein; a main flow path provided inside the second casing in a direction corresponding to an extension direction of the crankshaft, through which lubricating liquid to be supplied to the journal portion can flow; a secondary flow passage that connects the main flow passage with the journal portion and supplies the lubricating liquid to the journal portion; a fastening hole through which a fastening member for fastening the first housing and the second housing can be inserted; Equipped with a secondary flow passage and a fastening hole provided in non-overlapping positions on the same cross section, a tip end of the fastening hole disposed in the block portion, an inlet of the secondary flow passage connected to the main flow passage, and an outlet of the secondary flow passage connected to the journal portion at a position lower than the tip end and in the first housing.

2. The lubrication flow path structure for an internal combustion engine according to claim 1 , wherein the main flow path is located above the tip end of the fastening hole in the second housing.

3. 3. The lubrication flow path structure for an internal combustion engine according to claim 1, wherein the main flow path is disposed between an outer wall surface of the second housing and a side surface of the cylinder, and is biased toward the side surface.

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