JP2008064056A - Variable stroke characteristics engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve lubricity of a plurality of links in a variable stroke characteristics engine as well as weight reduction and rigidity thereof. <P>SOLUTION: In this variable stroke characteristics engine including a link 5, one of the plurality of links, which couples between a piston 3 and a crankshaft 6, and a control link 12 which couples between an eccentric shaft 13 supported by an engine body and a crankshaft 6, in which the piston stroke changes in response to the rotation of the eccentric shaft, a link includes a crankpin bore and an axial bore in a coupling shaft and an axial line of a lubricating path where lubricating oil flows from the crankpin bore to the axial bore is made approximately aligned with the tangential direction of an outer periphery of the coupling shaft, which assists the rotation of the coupling shaft and substantially improves the lubricating properties. In addition, each boss surrounding each bore and a projecting portion forming the lubricant passage are coupled to each other, thus attaining high rigidity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a variable stroke characteristic engine, and more particularly to a variable stroke characteristic engine having a plurality of links for changing the stroke characteristic.

The piston and crankshaft are connected by a plurality of links, and one of these links is connected to the eccentric shaft of the eccentric shaft supported by the engine body, and the eccentric shaft is rotated. 2. Description of the Related Art A stroke characteristic variable engine that changes a piston stroke by moving it is known (see, for example, Patent Document 1).
JP 2004-11634 A

  On the other hand, as a connection structure of a plurality of links, a structure in which a shaft support hole is provided in each link portion of each link and the connection shaft is inserted between the corresponding shaft support holes is known. In the case of a link connected to the crankpin of the crankshaft, the lubricating oil can be taken out from the lubricating oil supply path provided on the crankshaft and used for lubricating the connecting shaft. In that case, a lubricating oil passage is provided in the link, and in the communication structure with the shaft support hole of the lubricating oil passage, as seen in the above document, the outer peripheral surface of the connecting shaft The positional relationship is such that the axis of the lubricating oil passage is substantially orthogonal.

  In the above case, the lubricating oil that has flowed out to the outer peripheral surface of the connecting shaft flows in both directions with respect to the circumferential direction of the connecting shaft. However, if the connecting shaft does not rotate sufficiently, There is a risk that the lubricant will not spread around the circumference. In particular, in the variable stroke characteristic engine having the structure shown in the above document, the link connected to the crankpin swings and the connecting shaft at the connecting portion with other links does not always make one rotation. Therefore, there is a risk of insufficient lubrication.

  The present invention has been devised to eliminate such disadvantages of the prior art, and its main purpose is to improve the lubricity of a plurality of links, and to realize light weight and high rigidity. It is to provide a variable stroke characteristic engine.

  In order to solve such a problem, claim 1 of the present invention provides a plurality of links (4, 5) connecting between the piston (3) and the crankshaft (6), and one of the plurality of links. A control link (12) having one end rotatably connected to the link (5), and a control shaft that is movably provided on the engine body and supports the other end of the control link (12) so as to be swingable. (13) and a variable stroke characteristic engine in which the piston stroke is changed by moving the control shaft (13), the connecting shafts connecting the links (21, 22). Lubricating oil passages (27, 28) for supplying lubricating oil to the at least one link (5) are provided, and the connecting shafts (27, 28) of the connecting shaft ( The axis of the side facing the 1-22) was assumed, characterized in that facing the tangential direction of the outer peripheral surface of the connecting shaft (21, 22).

  According to a second aspect of the present invention, the one link (5) has a crankpin hole (25) rotatably supported by a crankpin (9) of the crankshaft (6). It consists of two divided bodies (5a, 5b) which are divided so as to sandwich the crank pin (9) in the radial direction by a hole (25) and are joined by bolts (26), and the lubricating oil is supplied to the crank pin (9 ) Is supplied to the crankpin hole (25), and the lubricating oil passages (27, 28) communicate with the crankpin hole (25) and are provided on the side away from the bolt (26). The invention of claim 3 is characterized in that the one link (5) is provided with two connecting shafts (21, 22), and the two links in the one link (5) are provided. Shaft (21/22) is supported A thin wall portion (29) is formed in a portion between the two shaft support holes (23, 24) and the crank pin hole (25), and the lubricating oil passage (27, 28) is connected to the crank pin hole ( 25) and the protrusions (34, 35) that extend so as to connect the outer peripheral part of the two shaft support holes (23, 24) and are thicker than the thin part (29). The invention according to claim 4 is characterized in that the one link (5) is provided between the outer peripheral portions (32, 33) of the two shaft support holes (23, 24). And a rib (36) for connecting the ribs (36) to the ribs (34, 35). (34, 35) is also connected to the bolt boss part (37) for receiving the bolt (26). The invention according to claim 6 is characterized in that the lubricating oil passage (27, 28) is not provided with the lubricating oil passage (27, 28) in the swing range of the one link (5). The invention according to claim 7 is characterized in that the lubricating oil passage (27, 28) has the portion that does not overlap the link (4, 12) when viewed from the axial direction of the crankshaft (6). Provided on the side where the gap between the connecting shaft (21, 22) and the shaft support hole (23, 24) becomes larger when the maximum explosion load from the piston (3) acts on the connecting shaft (21, 22). The invention of claim 8 is characterized in that the center of the lubricating oil passage (27, 28) and the center of the bolt hole (37a) into which the bolt (26) is inserted are the crankshaft (6). Characterized by being displaced in the axial direction of did.

  Thus, according to the first aspect of the present invention, since the flow direction of the lubricating oil supplied is the tangential direction of the outer periphery of the connecting shaft, when the link swings, the link between the link and the connecting shaft. In this case, the lubricating oil can easily go around and the lubricity is greatly improved, so that the link motion is smoothed and the efficiency of the engine can be improved.

  According to the second aspect of the present invention, since the lubricating oil passage can be formed while avoiding interference with the bolt fastening portion, the oil passage structure is not complicated. According to the third aspect, the rigidity around each shaft support hole can be easily increased. According to the fourth aspect, the rigidity around each shaft support hole can be further increased. Further, according to claim 5, when the link is formed to be thin for weight reduction, the portion for receiving the bolt is thicker than the thin portion, so that the lubricating oil is formed using the thickened portion. It is possible to further increase the rigidity of the portion to be performed, and to contribute to the high rigidity of all the links. According to claim 6, the lubricating oil path provided in one link has a portion that does not overlap with another link due to the movement during engine operation (the swing range of one link) when viewed from the crankshaft direction. By extending in this way, at least the size of the oil passage in that portion can be freely designed without being restricted by other links, and the degree of freedom in designing the lubricating oil passage is improved. According to the seventh aspect, since it becomes easy to supply the lubricating oil to the gap between the connecting shaft and the link support hole of the link, the link motion can be further smoothed, and the engine efficiency can be improved. According to the eighth aspect of the present invention, even if the lubricating oil passage and the bolt hole are arranged close to each other, a reduction in link rigidity can be suppressed.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  1 to 4 are schematic configuration diagrams in which the upper part is omitted from a cylinder head of a variable compression ratio engine as an example of a stroke characteristic variable engine to which the present invention is applied. Note that the valve operating mechanism, intake system, and exhaust system provided in the cylinder head are not different from the conventional 4-cycle engine. The piston 3 slidably engaged with the cylinder 2 of the engine 1 is connected to the crankshaft 6 through two links of the first link 4 and the second link 5 as one link in the present invention.

  The crankshaft 6 basically has the same configuration as that of a normal fixed compression ratio engine, and includes a crankpin 9 that is eccentric from a crank journal 8 (a center of rotation of the crankshaft) supported in the crankcase 7. An intermediate portion of the second link 5 that swings in a seesaw manner is supported by the crankpin 9. A small end 4 a at one end of the first link 4 is connected to the piston pin 10, and a large end 4 b at the other end is connected to one end 5 a of the second link 5. The crankshaft 6 is provided with a counterweight mainly for reducing the rotational primary vibration component of the piston motion, which is also the same as that of a conventional reciprocating engine and is omitted.

  The other end portion 5b of the second link 5 is pin-coupled with a small end portion 12a of one end of the control link 12 having the same configuration as a connecting rod for connecting a piston and a crankshaft in a normal engine. The large end portion 12b of the other end of the control link 12 is eccentrically decentered from the axis of the eccentric shaft 13 as a control shaft that is rotatably supported by the crankcase 7 and extends in parallel with the crankshaft 6. The shaft 13a is connected with a bearing hole 14 having a split structure. Thereby, the large end portion 12b as the other end portion of the control link 12 is swingably supported by the eccentric shaft 13.

  The eccentric shaft 13 supports the large end portion 12b of the control link 12 so as to be movable within a predetermined range (for example, about 90 degrees) within the crankcase 7, and is provided at a shaft end protruding outward from the crankcase 7. By the hydraulic drive mechanism, the rotation angle is continuously changed according to the operating state of the engine 1 and is held at an arbitrary angle.

  According to this engine 1, by rotating the eccentric shaft 13, the position of the large end portion 12b of the control link 12 is set to the position shown in FIGS. 1 and 2 (horizontal inward / low compression ratio state) and FIG. 4 (vertically downward / high compression ratio state), and the swing angle of the second link 5 changes as the crankshaft 6 rotates. As a result, the length of the connecting rod that connects the piston 3 and the crankshaft 6 exhibits an effect as if it changes continuously according to the movement of the piston 3 and is controlled by the rotation of the eccentric shaft 13. By changing the position of the support end of the link 12 with respect to the crankcase 7, the change rate of the length of the connecting rod can be arbitrarily set.

  In this way, the stroke range of the piston 3 in the cylinder 2, that is, the top dead center position and the bottom dead center position of the piston 3 are represented by the range indicated by the symbol A in FIG. 2 and the range indicated by the symbol B in FIG. It will change continuously between. That is, the first and second links 4 and 5, the control link 12, and the eccentric shaft 13 constitute a piston stroke characteristic variable mechanism, which makes it possible to continuously change at least one of the compression ratio and the displacement. A variable characteristic function is provided.

  Next, the connecting portion between the second link 5 and each of the links 4 and 12 will be described below with reference to FIG. As shown in FIG. 5, the second link 5, the first link 4, and the control link 12 are connected via connecting shafts 21 and 22, respectively. The second link 5 is provided with shaft support holes 23 and 24 for rotatably supporting the connection shafts 21 and 22. The connection shafts 21 and 22 and the links 4 and 12 may be fixed by press-fitting or the like, but the connection shafts 21 and 22 can be rotated to the links 4 and 12 by a circlip or the like. You may assemble to. When it is possible to rotate, the tangential flow of the lubricating oil with respect to the connecting shafts 21 and 22 can promote the rotation of the connecting shafts 21 and 22, and the rotation of the connecting shafts 21 and 22 greatly improves the lubricity. Therefore, the link motion is further smoothed.

  In addition, the second link 5 supports the crank pin 9 at its intermediate portion as described above, and is provided with a crank pin hole 25 for that purpose. The second link 5 includes a main body 5a and a cap 5b as two divided bodies in which the crankpin hole 25 is divided by a diameter portion so as to sandwich the crankpin 9 in the radial direction. Are connected by a pair of bolts 26 arranged in the above.

  Lubrication of the crankpin hole 25 may be the same as that of a normal engine, and as shown in FIG. 6, an oil supply passage 9a through which the lubricating oil fed from the oil pump P provided in the engine 1 to the crankshaft 6 is passed. Is provided in the crank pin 9, and the oil supply passage 9a and the outer peripheral surface of the crank pin 9 communicate with each other by, for example, two branch passages 9b and 9c. In this way, the lubricating oil is supplied between the crankpin hole 25 and the crankpin 9.

  Further, lubricating oil passages 27 and 28 that communicate the crankpin hole 25 and the shaft support holes 23 and 24 are provided inside the second link 5 (main body 5a). Lubricating oil supplied to the crankpin hole 25 is supplied to the shaft support holes 23 and 24 through the lubricating oil passages 27 and 28.

  And the opening position with respect to each axial support hole 23 * 24 of each lubricating oil path 27 * 28 is provided so that the tangential direction of the internal peripheral surface of each axial support hole 23 * 24 may face. In other words, the extension lines of the axis lines of the respective lubricating oil passages 27 and 28 are made to substantially coincide with the tangent lines of the outer peripheral surfaces of the corresponding connecting shafts 21 and 22.

  By doing so, the outflow direction of the lubricating oil supplied from the lubricating oil passage 27 to the shaft supporting hole 23 flows in one direction on the inner peripheral surface of the shaft supporting hole 23 as shown by an arrow C in FIG. become. Therefore, in the connecting shaft 21 that is supported by the shaft support hole 23, the lubricating oil always flows in one direction in the circumferential direction, and it is easy to rotate in that direction. Lubricating oil will spread. The same applies to the shaft support hole 24 (connection shaft 22).

  As a result, the connecting shafts 21 and 22 connected to the second link 5 that swings may not rotate once as they are, but the lubricating oil flows in one direction as described above. It becomes easy to rotate to. Accordingly, the rotation of the connecting shafts 21 and 22 can be promoted, and the lubricity is greatly improved by the rotation of the connecting shafts 21 and 22. Therefore, the movement of the link is smoothed, and the mechanical efficiency is improved.

  Further, in the second link 5, the respective lubricating oil passages 27 and 28 are provided in a portion away from the portion where the bolt 26 is fastened. Furthermore, the direction from the crankpin hole 25 to the shaft support holes 23 and 24 is the side away from the bolt 26. By doing so, interference with the bolts 26 can be avoided in the layout of the lubricating oil passages 27 and 28, so that the lubricating oil passages 27 and 28 are complicated, such as being able to be provided in a straight line as shown in the figure. There is nothing to do. The route of the lubricating oil passages 27 and 28 is not limited to a straight line, but may be a polygonal line or a curved line. In such a case, the axial direction in the vicinity of the opening to the shaft support holes 23 and 24 is connected. The tangential direction of the outer periphery of the shafts 21 and 22 (the inner periphery of the shaft support holes 23 and 24).

  Further, the second link 5 is thinned as much as possible for weight reduction, and between the crank pin hole 25 and the shaft support holes 23 and 24, as shown in FIG. A thin-walled portion 29 is provided. On the other hand, boss-shaped boss portions 31, 32, and 33 are formed so as to surround the crankpin hole 25 and the shaft support holes 23, 24 so as to have a necessary axial length.

  On the other hand, in order to ensure the required hole diameter of each lubricating oil path 27 and 28, each protrusion part 34 and 35 bulged in the thickness direction rather than the thin part 29 is formed, and inside each protrusion part 34 and 35 The lubricating oil passages 27 and 28 are formed. And the longitudinal direction (the axial direction of each lubricating oil path 27 * 28) both ends of each protrusion 34 * 35 are connected with each boss | hub part 31,32 * 33, and, thereby, each boss | hub part 31 * 32 is connected. 33, that is, the rigidity around the holes 23, 24, and 25 is increased, and the link motion is stabilized.

  In addition, wall-shaped ribs 36 are provided between the boss portions 31 and 32 of the shaft support holes 23 and 24, and both the boss portions 31 and 32 are connected via the ribs 36. Further, the connecting portions of the ribs 36 to the boss portions 31 and 32 are also connected to the ridge portions 34 and 35, so that only the ridge portions 34 and 35 are provided for the boss portions 31 and 32. In addition, since it is also connected to the rib 36, higher rigidity can be secured. Further, as described above, the protrusions 34 and 35 and the ribs 36 are also connected to each other, whereby the rigidity can be further increased. Weight reduction can also be achieved without forming the whole thick for such high rigidity and by using the protrusions 34 and 35 for forming the necessary lubricating oil passages 27 and 28.

  Further, the portion that receives the relatively thick bolt 26 is also formed as a bolt boss portion 37 that is thicker than the thin portion 29, and the closest portions of the bolt boss portion 37 and the ridge portions 34 and 35 are also connected to each other. Yes. In the illustrated example, as shown in FIG. 7, they are connected via a thick part 38 thicker than the thin part 29. Thereby, the rigidity of the part connected with the bolt boss part 37 in the lubricating oil passages 27 and 28 increases, and high rigidity can be promoted without forming a rigid part separately. The thick portion 38 may be formed as an extension of either the bolt boss portion 37 or the ridge portions 34 and 35.

  Further, as shown in FIG. 8, the portion of the second link 5 where the lubricating oil passages 27 and 28 are provided is in the axial direction of the crankshaft 6 (with respect to the swing ranges SW1 and SW2 of the other links 4 and 12). It has a portion that does not overlap when viewed from the front and back of the drawing. That is, in the second link 5, the portions other than the boss portions 32 and 33 that overlap the large end portion 4 b and the small end portion 12 a that are the connecting portions of the links 4 and 12 are in relation to the lubricating oil paths 27 and 28. The links 4 and 12 do not overlap in the swing ranges SW1 and SW2. Specifically, it is a portion provided with the ridge portions 34 and 35, and can be provided with the ridge portions 34 and 35 as in the illustrated example, or can have any other shape, and the lubricating oil provided in that portion The shape and size of the holes of the passages 27 and 28 can be designed freely. Therefore, the design freedom of the lubricating oil passages 27 and 28 can be improved.

  Further, as shown in FIG. 9, the large end portion 4a of the first link 4 may be formed in a bifurcated shape, and a corresponding portion (boss portion 32) of the second link 5 so as to be sandwiched between the bifurcated portions. Is provided. In such a connection structure, it is particularly effective to employ the structure that does not overlap. Of course, in the connection structure, the links 4 and 5 may be connected so that the connection shaft 21 is relatively cantilevered. In this case, the second link is provided on one side of the first link 4. Since the 5 swings, the shape on the other side (the thickness of the second link 5 and the like) can be freely designed, and therefore the design of the lubricating oil passage 34 is also free. The same applies to the control link 12, and illustration and description thereof are omitted. Moreover, although the connecting shaft 21 (22) has a solid pin shape, it may have a hollow cylindrical shape in order to promote weight reduction.

  Further, it is provided on the side where the clearance between the connecting shafts 21 and 22 and the shaft support holes 23 and 24 becomes larger when the maximum explosion load acts on the connecting shafts 21 and 22. That is, in the state where the maximum load during the explosion stroke is applied to the piston 3 shown in FIG. 3, as shown by the one-dot chain line in the figure, the connection center (piston pin center) Ca and the crank of the piston 3 and the first link 4 With respect to the line L connecting the center Cb of the pin 9, a portion extending in the tangential direction with respect to the connecting shaft 21 of the lubricating oil passage 27 is located on the opposite side to the side where the center Cc of the connecting shaft 21 is located. Has been. Thus, during an explosion, as shown in FIG. 10, the gap d1 on the lubricating oil passage 21 side is larger than the gap d2 on the opposite side in the gap between the connecting shaft 21 and the shaft support hole 23 (d1> d2). Therefore, the lubricating oil can be supplied more smoothly. Also, in the gap between the connecting shaft 22 and the shaft support hole 24, the gap d3 on the lubricating oil passage 28 side is larger than the gap d4 on the opposite side across the connecting shaft 22 (d3> d4). In the same manner as described above, the smooth supply of the lubricating oil is promoted.

  Further, as shown in FIG. 11, it is preferable that the centers of the lubricating oil passages 27 and 28 and the centers of the bolt holes 37 a into which the bolts 26 are inserted are shifted in the axial direction of the crankshaft 6. FIG. 11 is a diagram corresponding to FIG. 7, and the same reference numerals are given to the same parts as those in the above-described example, and the detailed description thereof is omitted. FIG. 11 shows that the center of the lubricating oil passage 27 is displaced relative to the center of the bolt hole 37a by a deviation amount e1 with respect to the axial direction of the crankshaft 6. By doing in this way, even if the bolt hole 37a and the lubricating oil passage 27 are brought close to each other in the direction along the surface of the second link 5, the distance (thickness) between the closest positions of both is kept long. Therefore, a decrease in rigidity of the second link 5 can be suppressed. FIG. 12 shows another example. In FIG. 12, instead of the lubricating oil passage 27, two lubricating oil passages 27a and 27b are provided. For example, in the connection structure between the second link 5 and the link 4 (12), the second link 5 side may be bifurcated and the link 4 (12) may have a single shape, contrary to the above. In this case, the two lubricating oil passages 27a and 27b are provided as shown in the figure so as to correspond to the fork at the connecting portion of the second link 5. The centers of the lubricating oil passages 27a and 27b are displaced relative to the center of the bolt hole 37a by a deviation amount e2 with respect to the axial direction of the crankshaft 6. It is.

  Note that the present invention can also be applied to a marine vessel propulsion engine such as an outboard motor having a vertical crankshaft.

It is a longitudinal cross-sectional view which shows the piston top dead center position in the low compression ratio state of the engine to which this invention was applied. It is a longitudinal cross-sectional view which shows the piston bottom dead center position in the low compression ratio state of the engine to which this invention was applied. It is a longitudinal cross-sectional view which shows the piston top dead center position in the high compression ratio state of the engine to which this invention was applied. It is a longitudinal cross-sectional view which shows the piston bottom dead center position in the high compression ratio state of the engine to which this invention was applied. It is a front view which shows the external appearance of a 2nd link. It is a principal part broken view of the 2nd link which shows a lubricating oil path. It is sectional drawing seen along the arrow VII-VII line of FIG. It is explanatory drawing which shows the relationship between the rocking | fluctuation range of a link, and a lubricating oil path. It is the principal part expanded sectional view seen along the arrow IX-IX line of FIG. It is a figure which shows the relationship of the clearance gap between a connection shaft and a shaft support hole. It is a figure which shows the example which shows the shift | offset | difference of a bolt hole and a lubricating oil path. It is another example which shows the shift | offset | difference of a bolt hole and a lubricating oil path.

Explanation of symbols

3 Pistons 4 and 5 Links 5a and 5b Divided bodies 6 Crankshaft 9 Crankpin 12 Control link 13 Eccentric shafts 21 and 22 Connecting shafts 23 and 24 Shaft support holes 25 Crankpin holes 26 Bolts 27 and 28 Lubricating oil passage 29 Thin portion 31・ 32 boss (outer periphery)
34/35 Projection 36 Rib 37 Bolt Boss

Claims (8)

A plurality of links connecting the piston and the crankshaft; a control link having one end pivotably connected to one of the plurality of links; and the control link movably provided on the engine body A variable-stroke-characteristic engine having a control shaft that slidably supports the other end portion thereof, and configured to change a piston stroke by moving the control shaft,
A lubricating oil passage for supplying lubricating oil to a connecting shaft that connects the links is provided in at least one link,
An engine having variable stroke characteristics, wherein an axis of the lubricating oil passage facing the connecting shaft is directed in a tangential direction of an outer peripheral surface of the connecting shaft. The one link has a crankpin hole rotatably supported by a crankpin of the crankshaft, and is divided by the crankpin hole so as to sandwich the crankpin in the radial direction and coupled by a bolt. It consists of two divisions,
The lubricating oil is supplied to the crank pin hole through the crank pin;
The variable stroke characteristic engine according to claim 1, wherein the lubricating oil passage is provided on a side communicating with the crank pin hole and away from the bolt. Two connecting shafts are provided on the one link,
A thin portion is formed in a portion between the two shaft support holes for supporting the two connecting shafts in the one link and the crank pin hole,
The lubricating oil passage is formed in each protrusion that extends so as to connect the outer peripheral portion of the crankpin hole and the outer peripheral portions of the two shaft support holes and is thicker than the thin portion. The variable stroke characteristic engine according to claim 2.   4. The rib according to claim 3, wherein the one link is provided with a rib that connects the outer peripheral portions of the two shaft support holes, and the rib is also connected to each of the protrusions. Stroke characteristic variable engine.   The stroke characteristic variable engine according to any one of claims 2 to 4, wherein the projecting portion is also connected to a bolt boss portion that receives the bolt.   The lubricating oil path has a portion that does not overlap with another link not provided with the lubricating oil path when viewed from the axial direction of the crankshaft in the swing range of the one link. The stroke characteristic variable engine according to any one of claims 1 to 5.   2. The lubricating oil passage is provided on a side where a gap between the connection shaft and the shaft support hole becomes larger when a maximum explosion load from the piston acts on the connection shaft. The stroke characteristic variable engine according to claim 6.   The center of the lubricating oil passage and the center of a bolt hole into which the bolt is inserted are disposed so as to be shifted in the axial direction of the crankshaft. Stroke characteristic variable engine.

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