JP5012677B2 - Variable compression ratio engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable compression ratio engine in which fretting wear is hard to occur. <P>SOLUTION: A plurality of buffer members 12 for preventing an outer wall surface of a cylinder block 21 and an inner wall surface of a crankcase from directly coming into contact with each other, even when the cylinder block 21 is inclined within the crankcase, are provided on a side surface (outer wall surface) of the cylinder block 21 of a variable compression ratio engine. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a variable compression ratio engine.

  If the compression ratio of the engine can be changed, the occurrence of knocking can be suppressed by lowering the compression ratio at high loads, and the torque can be extracted by increasing the compression ratio at low loads. Therefore, a variable compression ratio engine (for example, see Patent Documents 1 to 4) in which the cylinder block moves in the crankcase, or a variable compression ratio engine (piston) in which the crankshaft and the connecting rod are connected via a link. A variable compression ratio engine in which the top dead center and bottom dead center positions move up and down in the cylinder has been developed.

JP2007-303385A JP 2005-69179 A JP2005-140090 JP 2006-316664 A

  The present inventor has intensively studied to develop a variable compression ratio engine in which the cylinder block moves in the crankcase, and as a result, the variable compression ratio engine of this type is compressed for a long time. It has been found that fretting wear occurs at the lower part of the outer wall surface of the cylinder block as shown in FIG. It has also been found that fretting wear also occurs on the tooth surface of the worm gear that has continued for a long time. Further, it has been found that the tooth surface of the worm gear may increase wear when the variable compression ratio engine is operated in an intermediate compression ratio state. As shown in FIG. 8, the intermediate compression ratio state means that the line connecting the center of the worm wheel and the center of the shaft portion on which the worm wheel is eccentrically mounted is relative to the shaft center of the worm. It is a horizontal state.

  Accordingly, an object of the present invention is to provide a variable compression ratio engine in which fretting wear is less likely to occur.

  In order to solve the first problem, a variable compression ratio engine according to a first aspect of the present invention can displace a cylinder block having a cylinder and at least a part of the cylinder block in an axial direction of the cylinder. A crankcase housed in the form, and the cylinder block and the crankcase for changing the position of the cylinder block relative to the crankcase so that the cylinder block can be inclined and / or moved in a predetermined direction. A position change mechanism that supports the outer wall surface of the cylinder block and the outer wall surface of the cylinder block between the cylinder block and the crankcase even when the cylinder block is inclined and / or moved in the predetermined direction. A plurality of buffer members are provided to prevent direct contact with the inner wall surface of the crankcase. It has a configuration in which there.

That is, in the above-described variable compression ratio engine, fretting wear occurs on the outer surface of the cylinder block (and the inner surface of the crankcase) because the cylinder block tilts to the left and right in synchronization with the engine rotation (FIG. 4). However, the variable compression ratio engine of the first aspect of the present invention has a configuration in which the outer wall surface of the cylinder block and the inner wall surface of the crankcase are not in direct contact with each other even when the cylinder block is inclined. is doing. Therefore, this variable compression ratio engine is an engine in which fretting wear does not occur on the outer surface of the cylinder block (and the inner surface of the crankcase).

  Depending on the configuration of the position change mechanism (clearance between each part of the position change mechanism), the cylinder block can be tilted (or hardly tilted) in the crankcase, but is relatively large (cylinder block). The outer wall surface and the inner wall surface of the crankcase may be movable (vibrated). Since the fretting wear can occur even if the cylinder block vibrates in the crankcase, the position changing mechanism of the variable compression ratio engine according to the first aspect of the present invention is described as “the cylinder block and the crank. "Supporting the case in such a way that the cylinder block can be inclined in a predetermined direction", "supporting the cylinder block and the crankcase in such a way that the cylinder block can be inclined and moved in a predetermined direction", " The cylinder block and the crankcase may be any one that supports the cylinder block so that the cylinder block can move in a predetermined direction.

  Each of the variable compression ratio engines according to the first aspect of the present invention includes a position change mechanism that supports the cylinder block in such a manner that the variable compression ratio engine can be inclined in several directions (usually one direction) different from the predetermined direction. When the cylinder block is tilted in the direction, the cylinder block is inclined even if the cylinder block is tilted in a direction other than the predetermined direction. Some shock-absorbing members should be provided to prevent the outer wall surface of the crankshaft from directly contacting the inner wall surface of the crankcase.

In implementing a variable compression ratio engine of the first aspect of the present invention, as the position changing mechanism, Rutotomoni that having a second gear which is meshed with the first gear and the first gear, the position changing mechanism one or more buffer members in the supplied oil adopted mechanism for discharging between the inner wall surface of the crankcase and the outer wall surface of the cylinder block, said plurality of buffer members for lubrication, In a position where oil existing in a certain range between the outer wall surface of the cylinder block and the inner wall surface of the crankcase is guided to a portion where the first gear and the second gear of the position changing mechanism are engaged with each other. It can be provided.

  In the variable compression ratio engine of the present invention realized in such a manner, more oil is supplied to the portion where the first gear and the second gear are engaged. And if the amount of oil supplied increases, it will become difficult to produce fretting wear. Therefore, if the above configuration is adopted, fretting wear does not occur on the outer surface of the cylinder block, and the position control gears for the cylinder block (the first gear and the second gear in the position changing mechanism). Therefore, it is possible to realize a variable compression ratio engine in which fretting wear is unlikely to occur on the tooth surface.

  In realizing the variable compression ratio engine according to the first aspect of the present invention, at least one buffer member among the plurality of buffer members is disposed between the outer wall surface of the cylinder block and the inner wall surface of the crankcase. An oil seal can be provided to prevent the discharged oil from leaking outside. When this configuration is adopted, other buffer members may not be present in the vicinity of the oil seal (the buffer member that also functions as an oil seal), or other buffer members may be disposed in the vicinity of the oil seal. Can also exist.

A variable compression ratio engine according to a second aspect of the present invention includes a cylinder block having a cylinder, and a crankcase that houses at least a part of the cylinder block in a form that can be displaced in an axial direction of the cylinder. A position changing mechanism for changing the position of the cylinder block with respect to the crankcase, wherein the position changing mechanism has a first gear and a second gear meshed with the first gear. to Rutotomoni a mechanism for discharging between the inner wall surface of the supplied oil and the outer wall surface of the cylinder block the crankcase for lubrication of the position changing mechanism, wherein the outer wall surface of the cylinder block crank Within a certain range of the portion (between the outer wall surface of the cylinder block and the inner wall surface of the crankcase) between the inner wall surface of the case It has a structure in which one or more guide members for guiding the standing for oil to said first portion gear and the second gear is engaged in the position changing mechanism is provided.

  That is, the variable compression ratio engine of the second aspect of the present invention has a configuration in which more oil is supplied to the portion where the first gear and the second gear are engaged. And if the amount of oil supplied increases, fretting wear is less likely to occur, so this variable compression ratio engine is an engine that is less susceptible to fretting wear on the cylinder block position control gear. become.

  According to the present invention, it is possible to provide a variable compression ratio engine in which fretting wear is less likely to occur on an outer surface of a cylinder block or the like and a tooth surface of a gear for position control of the cylinder block or the like.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  A variable compression ratio engine according to an embodiment of the present invention is an improvement over an existing variable compression ratio engine.

  First, using FIG. 1 and FIG. 2, a portion of the variable compression ratio engine 10 according to the present embodiment having the same configuration as that of an existing variable compression ratio engine will be described.

  As shown in FIG. 1, the variable compression ratio engine 10 includes a cylinder block 21 having a plurality of cylinders, and a cylinder block 21 in the axial direction of the cylinder (hereinafter, the vertical direction (the side on which the cylinder head is attached is the upper side). An engine having a crankcase 22 that is held in a movable form and a compression ratio changing mechanism (corresponding to the position changing mechanism of the present invention) for changing the relative position of the cylinder block 21 to the crankcase 22. It is.

  Here, the compression ratio changing mechanism is provided on each longitudinal side surface of the motor 41 and the variable compression ratio engine 10 (the cylinder block 21 and the crankcase 22) attached to one longitudinal side surface of the crankcase 22. This is a mechanism comprising the eccentric shaft assembly 30, four free shaft housings 23, and the like.

  As shown in FIG. 2, each eccentric shaft assembly 30 used in this compression ratio changing mechanism includes a shaft portion 31, a worm wheel 32 fixed in an eccentric state with respect to the shaft portion 31, and This is a member comprising a plurality of free shafts 33 that are fixed to be rotatable with respect to the shaft portion 31 and a plurality of journals 34 that are fixed to be eccentric with respect to the shaft portion 31. In FIG. 2, only one eccentric shaft assembly 30 is shown. However, the other eccentric shaft assembly 30 is configured such that the illustrated eccentric shaft assembly 30 passes through the axis of each cylinder of the cylinder block 21. It has an inverted configuration.

The free shaft housing 23 (FIG. 1) is a member for fixing the free shaft 33 of the eccentric shaft assembly 30 to the cylinder block 21 in a rotatable manner. The free shaft housing 23 includes a through hole having a size through which the free shaft 33 of the eccentric shaft assembly 30 passes with a predetermined clearance. The free shaft housing 23 is attached to the free shaft 33 portion of the eccentric shaft assembly 30 and then passes through the openings provided in the longitudinal side surfaces of the crankcase 22 (different from the shape shown in the figure). In the form of a member fixed to the cylinder block 21.

  By attaching an eccentric shaft cover 25 to each longitudinal side surface of the crankcase 22, a portion (in the drawing) that functions as a bearing for each journal 34 (and at least a part of the shaft portion 31) of the eccentric shaft assembly 30. , Main bearings) are also provided. Further, a drive shaft provided with a worm 42 (see FIGS. 1 and 2) is rotatably held in a lower portion of the crankcase 22 at a position where it engages with the worm wheel 32 of each eccentric shaft assembly 30 in the compression ratio changing mechanism. Has been. Note that the two worms 42 provided in the drive shaft are formed with screws in opposite directions.

  The compression ratio changing mechanism provided in the variable compression ratio engine 10 is provided with a motor 41 for rotating the drive shaft on the side surface in the longitudinal direction of the crankcase 22 (see FIG. 1).

  Furthermore, the compression ratio changing mechanism is a mechanism in which each part is lubricated with lubricating oil. Specifically, each free shaft 33 of the eccentric shaft assembly 30 (see FIG. 2) has a plurality of oil supply holes communicating with each other in the thickness direction, and a plurality of oil supply holes formed on the inner surface thereof. It is a member in which a concave portion having a shape that connects the outlets (a shape that goes around the inner surface of the free shaft 33) is formed.

  The shaft portion 31 of the eccentric shaft assembly 30 is formed with a passage for flowing lubricating oil at the center (axial center) portion, and a plurality of portions that communicate with the concave portions of the free shafts 33 in the thickness direction. It is a member in which individual holes are formed. The variable compression ratio engine 10 is an engine configured such that lubricating oil from an oil pump (not shown) is supplied to the compression ratio changing mechanism from the end of each shaft portion 31.

  An oil seal 11 is attached to an upper portion of the cylinder block 21 of the variable compression ratio engine 10 (a portion facing a portion near the upper end of the crankcase 22).

  This oil seal 11 is supplied to the compression ratio changing mechanism (lubricating oil that has flowed out from the gap between the free shaft 33 and the free shaft housing 23 into the gap between the cylinder block 21 and the crankcase 22). Is a member for preventing leakage from the engine.

  More specifically, a groove having a shape that goes around the side surface of the cylinder block 21 is formed in an upper portion of the cylinder block 21 (a portion facing a portion near the upper end of the crankcase 22). The oil seal 11 is a ring-shaped member having a thickness capable of sealing a gap between the cylinder block 21 and the crankcase 22 attached to the cylinder block 21 by fitting into the groove. The variable compression ratio engine 10 employs an oil seal 11 in which a ring-shaped rubber member and a ring-shaped fluororesin member are laminated (the crankcase 22 side is a fluororesin member). Yes.

  Based on the above, the configuration and operation of the variable compression ratio engine 10 according to the present embodiment will be described more specifically below.

  As shown in FIG. 3 (and FIG. 1), a plurality of buffer members 12 are attached to each outer wall surface of the cylinder block 21 provided in the variable compression ratio engine 10.

The buffer member 12 is a flexible member that is fitted in a recess formed in each portion of each outer surface of the cylinder block 21. The buffer member 12 has a thickness such that the amount of protrusion from the outer surface of the cylinder block 21 is greater than the distance between the outer wall surface of the cylinder block 21 and the inner wall surface of the crankcase 22. Further, the buffer member 12 is a member having a low coefficient of friction with respect to the inner wall surface of the crankcase 22 (in this embodiment, a rubber member and a fluorine resin member are laminated; the crankcase 22 side is a fluorine resin member). Yes.

  Then, as is apparent from the drawing, the cylinder block 21 of the variable compression ratio engine 10 has such a buffer member 12 in place near the lower end of each outer surface and the oil seal 11 near the upper end of each outer surface. It is attached to various places below.

  Therefore, in the variable compression ratio engine 10 according to the present embodiment, fretting wear does not occur between the outer wall surface of the cylinder block 21 and the inner wall surface of the crankcase 22, and the tooth surface of the worm gear (the teeth of the worm 42). It functions as an engine in which fretting wear hardly occurs on the surface and the tooth surface of the worm wheel 32).

  Specifically, the cylinder block 21 of the present variable compression ratio engine 10 is supported by two eccentric shaft assemblies 30 having free shafts 33, like the cylinder block of a general variable compression ratio engine of the same type. Yes. For this reason, the cylinder block 21 can be inclined at a certain angle in the direction in which the eccentric shaft assemblies 30 are arranged in the crankcase 22.

  During the rotation of the engine, a periodic force corresponding to the pressure fluctuation in the piston is applied between the cylinder block 21 and the crankcase 22, so that when the variable compression ratio engine 10 is started, FIG. As shown, the cylinder block 21 tilts to the left and right in synchronization with the engine rotation.

  However, as shown in FIG. 5, the cylinder block 21 of the variable compression ratio engine 10 is configured such that the buffer member 12 is attached to the upper and lower portions of each longitudinal side surface.

  Therefore, the variable compression ratio engine 10 is an engine having a smaller angle at which the cylinder block 21 can be tilted in the crankcase 22 than the existing variable compression ratio engine, and the cylinder block 21 is tilted in the crankcase 22. Even so, the engine is such that the outer wall surface of the cylinder block 21 and the inner wall surface of the crankcase 22 are not in direct contact.

  Since the fretting wear does not occur unless the outer wall surface of the cylinder block 21 and the inner wall surface of the crankcase 22 are in direct contact with each other, the variable compression ratio engine 10 has the outer wall surface of the cylinder block 21 and the like. Therefore, the engine is free from fretting wear.

  Further, as schematically shown in FIG. 7, the two buffer members 12 attached to the central lower end portions of the side surfaces in the longitudinal direction of the cylinder block 21 are used to transfer oil existing above them to the worm 42. It functions as a member that leads to a portion where the worm wheel 32 is engaged.

  Therefore, the variable compression ratio engine 10 has a larger amount of lubricating oil supplied to the portion where the worm 42 and the worm wheel 32 are engaged with each other than the variable compression ratio engine in which the buffer member 12 is not provided. It will be an engine. Then, if the amount of lubricating oil supplied to the portion where the worm 42 and the worm wheel 32 are engaged with each other increases, fretting wear is less likely to occur. This also means that the engine is less prone to fretting wear on the tooth surface.

<Deformation>
The variable compression ratio engine 10 described above can be variously modified. For example, the variable compression ratio engine 10 can be modified to have a cylinder block 21 (see FIG. 3) in which the buffer member 12 is not provided near the oil seal 11. However, if the buffer member 12 is provided near the oil seal 11 (if the configuration of the embodiment is adopted), the force / impact generated by the inclination of the cylinder block 21 is caused by the oil seal 11 and the buffer member 12. It will be received. And as a result, since it becomes possible to delay the time when the oil seal 11 deteriorates, it is preferable to employ the configuration of the embodiment.

  The variable compression ratio engine 10 is transformed into one having a cylinder block 21 in which the buffer member 12 is not provided on each lateral side surface, or one having the buffer member 12 attached to the inner wall surface of the crankcase 22. You can also. Further, the variable compression ratio engine 10 may be an engine other than the engine in which the worm gear (worm 42 & worm wheel 32) is provided at a position different from the above-described position (for example, one short side surface of the crankcase 22). It can also be transformed into an engine that uses gears.

  Further, depending on the configuration of the position change mechanism (clearance between each part of the position change mechanism), the cylinder block 21 can be tilted in the crankcase 22 (or can hardly be tilted), but relatively in the left-right direction. May be able to vibrate (move) by a large amount (amount that allows the outer wall surface of the cylinder block 21 and the inner wall surface of the crankcase 22 to contact each other). Further, fretting wear can occur even when the cylinder block 21 vibrates in the crankcase 22. Accordingly, the technical idea that the buffer member 12 is provided between the cylinder block 21 and the crankcase 22 is the same as the variable compression ratio engine 10 in which the cylinder block 21 can be tilted and vibrated in the crankcase 22 and the cylinder block 21 is cranked. Of course, the present invention may be applied to the variable compression ratio engine 10 that can vibrate in the case 22.

1 is an exploded view of a variable compression ratio engine according to an embodiment of the present invention. It is a principal part block diagram of the variable compression ratio engine which concerns on embodiment. It is a side view of the cylinder block with which the variable compression ratio engine which concerns on embodiment is provided. It is explanatory drawing of the reason why fretting wear arises in the outer wall surface etc. of a cylinder block. It is explanatory drawing of the attachment position of the buffer member with respect to a cylinder block. It is explanatory drawing of the way of the lubricating oil flow in the worm wheel vicinity in the variable compression ratio engine of embodiment. It is explanatory drawing of the fault which the conventional variable compression ratio engine has. Explanatory drawing of the positional relationship of a worm wheel and a shaft part in an intermediate compression ratio state.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Variable compression ratio engine 11 ... Oil seal 12 ... Buffer member 21 ... Cylinder block 22 ... Crank case 23 ... Free shaft housing 30 ... Eccentric shaft assembly 31 ... Shaft 32 ... Worm wheel 33 ... Free shaft 34 ... Journal 41 ... Motor 42 ... Worm

Claims (3)

A cylinder block having a cylinder;
A crankcase that houses at least a part of the cylinder block in a form displaceable in the axial direction of the cylinder;
A position changing mechanism for changing the position of the cylinder block with respect to the crankcase, and supporting the cylinder block and the crankcase in such a manner that the cylinder block can be inclined and / or moved in a predetermined direction ;
Provided between the cylinder block and the crankcase, also the cylinder block is inclined and / or moved in the predetermined direction and the outer wall surface of the cylinder block and the inner wall surface of the crankcase does not contact directly and a plurality of cushioning member for way,
The position changing mechanism includes a first gear and a second gear meshed with the first gear, and supplies oil supplied for lubrication of the position changing mechanism to the outer wall surface of the cylinder block and the crankcase. It is a mechanism that discharges between the inner wall surface,
One or more buffer members among the plurality of buffer members may be configured to transfer oil existing in a certain range between an outer wall surface of the cylinder block and an inner wall surface of the crankcase to the first gear of the position changing mechanism. The variable compression ratio engine is provided at a position that leads to a portion where the second gear is engaged with the second gear . At least one buffer member of the plurality of buffer members is
A variable compression ratio according to claim 1 Symbol placement, wherein the discharged oil is an oil seal for preventing the leaking out between the outer wall surface and inner wall surface of the crankcase of the cylinder block engine. A cylinder block having a cylinder;
A crankcase that houses at least a part of the cylinder block in a form displaceable in the axial direction of the cylinder;
A position changing mechanism for changing the position of the cylinder block with respect to the crankcase,
The repositioning Organization is Rutotomoni that having a second gear which is meshed with the first gear and the first gear, wherein the supplied oil and the outer wall surface of the cylinder block for lubrication of the position changing mechanism It is a mechanism that discharges between the inner wall surface of the crankcase,
Between the outer wall surface of the cylinder block and the inner wall surface of the crankcase, oil existing in a certain range of the portion is transferred to a portion where the first gear and the second gear of the position changing mechanism are engaged with each other. A variable compression ratio engine characterized in that one or more induction members for induction are provided.

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