JP5334782B2 - Internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce energy loss by suppressing a friction resistance in an internal combustion engine wherein a connecting rod only reciprocates. <P>SOLUTION: The internal combustion engine includes a cylinder bore in which a piston slides, and a crank shaft 4 driven by the piston. The crank shaft 4 has rotation center shafts 5, 6 and a crank 7, and the rotation center shaft 5 is rotatably held by a first journal 10. An idling rotor 17 is fitted in the crank 7 in an eccentric state, and the connecting rod is coupled to the idling rotor 17 so as to relatively rotate. The idling rotor 17 is provided with a planetary gear 23, and the planetary gear 23 is engaged with an inner tooth gear. A second clearance E2 between the crank 7 and a second journal 16 is set to be larger than the first clearance E1 between the rotation center shaft 5 and the first journal 10. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a reciprocating internal combustion engine that extracts the reciprocating motion of a piston as rotational power, such as a gasoline engine or a diesel engine, and more particularly relates to an internal combustion engine of a type in which a connecting rod only reciprocates without rotating. It is.

  In an internal combustion engine, a crank mechanism is generally employed as a means for taking out the reciprocating motion of a piston as rotational power. In a normal internal combustion engine, the crankshaft is rotatably held by the engine body and is eccentric from the rotational axis. The crank pin and the piston are connected by a connecting rod. Therefore, the connecting rod reciprocates while changing the angle, but the piston and cylinder bore are subject to wear because an external force is applied to the piston by changing the angle of the connecting rod. There were also problems such as large sliding resistance (energy loss).

  Therefore, a mechanism for obtaining a rotational motion by only reciprocating the connecting rod has been considered. As an example, Patent Document 1 discloses that a large-diameter rotation collar (a kind of rotary damper, corresponding to the idle rotor of the present application) is rotatably fitted to the large end of the connecting rod, and the rotation collar is connected to the crank portion of the crankshaft. And the rotation collar rotates around the axis of the crank part while revolving around the rotation center axis of the crankshaft by setting the eccentric dimension of the rotation collar to be the same as the eccentric dimension of the crank part. Further, the rotation collar is provided with a planetary gear concentric with the crank portion, and the planetary gear is meshed with an internal gear fixed to the engine body, so that the rotation collar is connected to the rotation direction of the crank portion. A mechanism is disclosed in which the connecting rod is restricted to rotate in the reverse direction, so that the connecting rod does not rotate but only reciprocates.

Japanese Patent Publication No. 50-39203

  In Patent Document 1, the rotation center shafts at the left and right ends of the crankshaft are rotatably held by ball bearings, but a metal bearing system is preferable from the viewpoint of durability and cost. In a multi-cylinder internal combustion engine, when there are three or more rotation center shafts on the crankshaft, the bearing may have to be split, and the bearing in this case is necessarily a metal bearing. Further, in the drawing of Patent Document 1, a state in which the rotation collar is directly fitted into the crank portion is depicted, but in reality, a bearing is fitted into the rotation collar and the crank portion is supported by this bearing. preferable.

  Accordingly, the inventors of the present application prototyped an internal combustion engine in which the rotation center shaft of the crank was formed with a metal-type first journal and the bearing of the crank portion was also formed with a metal-type second journal. This is presumed to be due to the large weight of the reciprocating motion and the inertial force of the reciprocating motion, but there is a phenomenon that the crankshaft is twisted or the planetary gear is strongly pressed against the internal gear, which may increase the energy loss. There was something.

  Therefore, the inventors of the present application have studied, and it has been found that the crankshaft is twisted and the strong pressing action between the planetary gear and the internal gear is closely related to the clearance between the first journal and the second journal. did. The present invention has been made on the basis of such knowledge, and an object of the present invention is to reduce energy loss with a simple configuration in an internal combustion engine in which a connecting rod reciprocates only.

  The present invention relates to an internal combustion engine. The internal combustion engine includes a piston that reciprocates a cylinder bore, a connecting rod having one end connected to the piston, a crankshaft, and a reciprocating motion of the connecting rod for rotating the crankshaft. An idler rotor for conversion, and the crankshaft is positioned between a plurality of rotation center shafts separated in the axial direction and adjacent rotation center shafts in an eccentric state from the rotation center of the rotation center shaft. And a crank arm that connects the rotation center shaft and the crank portion. Each rotation center shaft of the crank shaft is rotatably held by the engine body via a first journal.

  On the other hand, the idler rotor has a crankpin portion having a diameter larger than that of the crank portion and in which the connecting rod is rotatably fitted, and at a position eccentric from the axis of the crankpin portion. A planetary gear concentric with the crank part is attached to the idler rotor via a journal, and the internal gear that meshes with the planetary gear is attached to the engine body. It is provided concentrically with the rotation axis of the central shaft, and the dimension in which the crank part is eccentric from the rotation center line of the crankshaft and the dimension in which the axis of the crank pin part is eccentric from the axis of the crank part are the same dimension. By setting to, it is allowed that the idle rotor rotates in the direction opposite to the revolution direction of the crank portion and the connecting rod does not rotate but only reciprocates.

  According to a first aspect of the present invention, in the above basic configuration, a first clearance is provided between the first journal and the rotation center shaft, and the first journal is provided between the second journal and the crank portion. A second clearance larger than the clearance is provided.

  Since the invention of claim 2 suitably embodies the invention of claim 1, in this invention, the planetary gear concentric with the crank portion is positioned outside the connecting rod in the idler rotor. On the other hand, the engine body is provided with an internal gear meshed with the planetary gear concentrically with the rotation axis of the rotation center axis.

  The invention of claim 3 is the one in which the invention of claims 1 and 2 is applied to a multi-cylinder (multi-cylinder) internal combustion engine. The invention comprises a plurality of cylinder bores and pistons, and the crankshaft has three The rotation center shaft described above and a number of crank portions that are one less than the number of the rotation center shafts are provided, and a connecting rod is connected to each crank portion via an idler rotor.

Now, the pressing force of the piston acts on the idler rotor via a connecting rod, acts from idle rotor to the crank portion of the crankshaft, the deflection crank portion occurs, those 該Ku rank unit and free rotation the rotor A twist occurs (per piece), and this becomes a resistance to rotation and energy loss occurs.

More specifically, when the pressing force of the free-rotating rotor acts evenly over the entire length of the crank portion, the free-rotating rotor is in contact with only one portion of the crank portion sandwiching the shaft center, and the twisting occurs. However, when bending occurs in the crank part , the crank rotor comes into contact with the non-uniform state on one side and the other side across the shaft center, so that the crank part and the free rotor A large frictional resistance (twisting) occurs between the two.

  In the present invention, since the rotation center shaft of the crankshaft has a larger diameter than the crank portion, the first journal can be held rotatably without being twisted. Therefore, even if the crank portion is bent, the crank portion It is possible to maintain a state in which the second journal abuts only on one side of the shaft center and a gap remains on the other side, and as a result, the twist between the second journal and the crank portion is eliminated. Energy loss (friction resistance) can be remarkably suppressed.

  In other words, even if the crank portion is bent due to the pressing force of the second journal, the rotation center shaft is moved before the opposite side of the second journal where the pressing force is applied hits the crank portion. As a result, it keeps the smooth rotation of the rotation center shaft by the first journal, while suppressing the occurrence of the energy loss due to the twist between the second journal and the crank portion. It can be done.

  Since the first journal portion slides with the shaft at half the number of rotations compared to the second journal portion, the first journal portion is caused by the deflection of the crankshaft as compared with the second journal portion. Wear is difficult to occur.

  Furthermore, since the first clearance is smaller than the second clearance, even if the crankshaft itself moves within the first journal by the amount of the first clearance, the planetary gear is more strongly pressed than the internal gear. As a result, the energy loss due to the planetary gear being strongly pressed against the internal gear can be remarkably suppressed.

In addition, when the planetary gear and the internal gear are provided, the connecting rod can be firmly controlled so that it only reciprocates. However, the planetary gear is provided at a location away from the rotating rotor, so the influence of the bending of the crank portion For example, if the first clearance and the second clearance are the same, the planetary gear tends to be strongly pressed against the internal gear before the first journal supports the rotation center shaft. For this reason, energy loss is noticeable.

In contrast, in the present invention, although the planetary gear and the internal gear are provided, even if the crank portion is bent, the planetary gear rotates before being strongly pressed by the internal gear. The central axis comes into contact with the first journal over its entire length, and as a result, energy loss caused by the planetary gear being strongly pressed against the internal gear can be remarkably suppressed. If the planetary gear and the internal gear are provided as in claim 2, the positions of the planetary gear and the internal gear are close to the position of the first journal provided on the crankshaft. Since the position of the planetary gear is close to the position, even if the crankshaft is bent, the amount of movement of the planetary gear due to the bending is reduced. As a result, the planetary gear is strongly pressed against the internal gear, or the planetary gear is tilted. It is possible to remarkably suppress the energy loss and the uneven wear of the gear caused by meshing with the internal gear in the state of being caught.

  The present invention can also be easily applied to a multi-cylinder internal combustion engine by providing a plurality of crank portions as in claim 3.

It is a vertical front view of an embodiment. It is a vertical front view of the principal part. 2A is a cross-sectional view taken along the line AA in FIG. 2, FIG. 2B is a cross-sectional view taken along the line BB in FIG. 2, and FIG. (A) is sectional drawing which shows the bearing structure of a crankshaft, (B) is BB sectional drawing of (A), (C) is CC sectional drawing of (A), (B) ( In C), the clearance is exaggerated.

  Next, an embodiment of the present invention will be described with reference to the drawings. In the following description, the terms “left / right” and “front / rear” are used to specify the direction, but this is based on a state viewed from a direction orthogonal to the axis of the crankshaft (ie, when looking straight at FIG. 1). I have to.

  The internal combustion engine of the present embodiment is a two-cylinder four-cycle system. Therefore, two cylinder bores 2 are formed in parallel in the engine body (cylinder block) 1, and a piston 3 is slidable in each cylinder bore 2. It is fitted.

  A crankshaft 4 extending along the direction in which the pistons 3 are arranged is disposed below the pistons 3. The crankshaft 4 has three rotation center axes, that is, a side rotation center shaft 5 located near one end and the other end of the crankshaft 4 and a center rotation center shaft 6 located substantially in the middle of the left and right sides. A crank portion 7 is arranged at a position between the rotation center shafts 5 and 6 while being eccentric from the rotation axis O1 of the rotation center shafts 5 and 6 by a dimension E. The portion 7 is integrally connected via a side crank arm 8 and a center crank arm 9.

Each rotation center shaft 5, 6 is rotatably held by a first journal (metal bearing) 10 fixed to the engine body 1. A main boss portion 11 to which a pulley and a gear are fixed is provided on one of the left and right side rotation center shafts 5, and a sub boss portion 12 to which a flywheel is fixed to the other side rotation center shaft 5. Is provided. The crank arms 8 and 9 are integrally provided with balance weights 13 and 14 protruding in a direction opposite to the eccentric direction.

  The left and right crank portions 7, the center crank arm 9, and the center rotation center shaft 6 are integrally structured, and the left and right side rotation center shaft 5 and the side crank arm 8 are each integrally structured. Accordingly, the crankshaft 4 of the present embodiment is composed of three members, and the front end portions of the left and right crank portions 7 are fitted and fixed to the side crank arms 8. Needless to say, the entire crankshaft 4 can be an integral structure. The crank portion 7 is formed in a perfect circle, and its outer diameter D2 is set to about half of the outer diameter D1 of the rotation center shafts 5 and 6.

  An idle rotor 17 is fitted to the crank portion 7 from the outside via a second journal 16. The idler rotor 17 has a groove-shaped crankpin portion 18 having a diameter larger than that of the rotation center shafts 5 and 6, and this crankpin portion 18 is connected to the large end portion (bearing portion) 19a of the connecting rod 19 from the outside. I hold it in relative rotation. The lower half of the large end portion 19 a of the connecting rod 19 is constituted by a lower member 19 b of another part, and this is fastened to the upper portion by a bolt 20. The upper end of the connecting rod 19 is connected to the piston 3 with a piston pin or the like, but the connecting structure is omitted in the drawing.

  The idle rotor 17 is fitted to the crank portion 7 in an eccentric state with respect to the rotation center O3 of the crank pin portion 18. The eccentric dimension of the idle rotor 17 with respect to the crank part 7 and the eccentric dimension of the crank part 7 with respect to the rotation center shafts 5 and 6 are set to the same dimension E. The idle rotor 17 is integrally provided with a balance weight 21 in the state of being close to the center crank arm 9. The balance weight 21 protrudes toward the opposite side of the axis O3 of the idle rotor 17 with the crank portion 7 interposed therebetween.

  The left and right idler rotors 17 are integrally provided with a small-diameter cylindrical portion 22 projecting to the opposite side (ie, outside) of the center crank arm 9, and a planetary gear 23 is fixed to the cylindrical portion 22 (planetary planets). The gear 23 may be integrally formed with the idle rotor 17). On the other hand, an internal gear 24 that meshes with the planetary gear 23 is fixed to the engine body 1. The number of teeth of the internal gear 24 is set to twice the number of teeth of the planetary gear 23.

As shown in FIG. 4, there is a first clearance E <b> 1 between the rotation center shafts 5, 6 and the first journal 10, and a second clearance is also provided between the crank portion 7 and the second journal 16. E2 exists, but E1 <E2 is set. Specifically, E1 is 17μ
± 8μ and E2 were preferably 25μ or more. More precisely, E2 is preferably about 30 to 40 μm larger than E1.

Since the crank portion 7 is provided with the idler rotor 17 and the planetary gear 23, a certain length (span) is required, but the rotation center shaft 5 has a minimum length necessary for its function. If there is enough. For this reason, the length of the crank portion 7 is several times the length of the rotation center shaft 5. Further, although not shown, it is provided an oil passage for supplying oil to the journal 10, 16 to the crankshaft 4.

(2) Summary of the first embodiment In the above configuration, one cylinder bore 2 undergoes an explosion / exhaust / intake / compression stroke every four cycles in which the piston 3 reciprocates twice, and the two cylinder bores 2 The explosion process and exhaust process are shifted by two cycles.

  The crank portion 7 revolves around the axis O1 of the rotation center shaft 5 by the pressing and pulling action of the connecting rod 19, and the free-rotating rotor 17 and the crank portion 7 have the axis O1 of the rotation center shaft 5. Revolving around the axis O2 of the crank portion 7 while revolving around. Then, the revolving direction of the crank portion 7 and the rotation direction of the free-rotating rotor 17 are reversed by the restriction function by the meshing between the planetary gear 23 and the internal gear 24. Since the eccentric dimension E of the crank part 7 with respect to the axis O1 of the rotation center shaft 5 is the same as the eccentric dimension E of the idle rotor 17 with respect to the crank part 7, the connecting rod 19 only reciprocates. .

  Now, as shown exaggeratedly by the dotted line 7 ′ in FIG. 4, it is assumed that the crank portion 7 is bent and deformed by the pressing force by the idle rotor 17. When the crank portion 7 is bent and deformed in this way, referring to FIG. 4, if there is no clearance between the second journal 16 and the crank portion 7, the crank portion 7 is located at the position X in the second journal 16. The second journal 16 has a tendency to be strongly pressed upward by the second journal 16. For this reason, a twist occurs between the crank portion 7 and the second journal 16 to increase the frictional resistance, and the planetary gear 23 is strongly pressed by the internal gear 24 to increase the frictional resistance.

  On the other hand, in the present invention, since the second clearance E2 between the crank portion 7 and the second journal 16 is larger than the first clearance E1 between the rotation center shaft 5 and the first journal 10, the crank portion is temporarily assumed. 7, the rotation center shaft 5 is brought into the lower surface of the first journal 10 before the crank portion 7 is pushed up by the second journal 16 at the position Y, as indicated by Z in FIG. This makes it possible to maintain a state where there is a gap between the lower surface of the crank portion 7 and the second journal 16, and as a result, the one-side contact phenomenon and the phenomenon in which the planetary gear 23 is strongly pressed by the internal gear 24. It can be avoided.

  Since the rotation center shaft 5 has a larger diameter than the crank portion 7 and its axial length is much shorter than the crank portion 7, the rotation center shaft 5 is twisted between the rotation center shaft 5 and the first journal 10 (per one side). ) Does not occur.

  Further, even if the crankshaft 4 itself moves within the first journal 10 by the first clearance E1, the rotation center shafts 5, 6 before the planetary gear 23 is strongly pressed by the internal gear 24. Comes into contact with the first journal 10 over its entire length, and as a result, energy loss due to the planetary gear 23 being strongly pressed against the internal gear 24 can be remarkably suppressed.

Further , a planetary gear 23 concentric with the crank portion 7 is attached to the idler rotor 17 so as to be positioned outside the connecting rod 19, while an internal gear with which the planetary gear 23 meshes with the engine body 1. 24 is provided concentrically with the rotation axis of the rotation center shafts 5 and 6, the positions of the planetary gear 23 and the internal gear 24 are close to the positions of the first journal 10 provided at both ends of the crankshaft. In other words, since the crankshaft 4 is close to the fulcrum position of the deflection, even when the crankshaft 4 is bent, the amount of movement of the planetary gear 23 due to the bending is reduced. As a result, the planetary gear 23 is moved to the internal gear. It is possible to remarkably suppress energy loss caused by being strongly pressed by 24 or meshing with the internal gear 24 while the planetary gear 23 is tilted. In this case, the second clearance E2 can be reduced within a range that does not become smaller than the first clearance E1.

(3). Others The present invention can be embodied in various ways other than the above embodiment. For example, the number of cylinders is not limited to two, but can be applied to an internal combustion engine having a single cylinder or three or more cylinders. When applied to a two-cylinder two-cycle internal combustion engine, the phases of the two crank portions may be shifted by 180 degrees. It is also possible to connect a plurality of connecting rods to one crank part.

  The present invention can be applied to an internal combustion engine to exhibit its usefulness. Therefore, it can be used industrially.

DESCRIPTION OF SYMBOLS 1 Engine main body 2 Cylinder bore 3 Piston 4 Crankshaft 5,6 Rotation center shaft 7 Crank part 8,9 Crank arm 10 First journal 16 Second journal 18 Crankpin part 19 Connecting rod 23 Planetary gear 24 Internal gear

Claims (3)

A piston that reciprocates the cylinder bore, a connecting rod having one end connected to the piston, a crankshaft, and a free-rotating rotor that converts the reciprocating motion of the connecting rod into rotation of the crankshaft,
The crankshaft includes a plurality of rotation center shafts separated in an axial direction, a crank portion positioned between the rotation center shafts adjacent to each other while being eccentric from the rotation center of the rotation center shaft, and the rotation center shaft and the crank Each of the crankshafts is rotatably held by the engine body via the first journal,
The idler rotor has a crankpin portion having a diameter larger than that of the crank portion and the connecting rod is rotatably fitted thereto, and the second journal is placed at a position eccentric from the axis of the crankpin portion. A planetary gear concentric with the crank portion is attached to the idler rotor, and an internal gear engaged with the planetary gear is attached to the engine body. Is provided concentrically with the rotation axis of
By setting the dimension in which the crank part is eccentric from the rotation center line of the crankshaft and the dimension in which the axis of the crankpin part is eccentric from the axis of the crank part to the same dimension, It is allowed to rotate in the direction opposite to the revolution direction and the connecting rod does not rotate but only reciprocates.
The structure
A first clearance is provided between the first journal and the rotation center shaft, and a second clearance larger than the first clearance is provided between the second journal and the crank portion.
Internal combustion engine. A planetary gear concentric with the crank portion is attached to the idler rotor so as to be positioned outside the connecting rod, and an internal gear engaged with the planetary gear is attached to the engine body as a central axis of rotation. Is provided concentrically with the rotation axis of
The internal combustion engine according to claim 1. A plurality of cylinder bores and pistons are provided, and the crankshaft is provided with three or more rotation center shafts and one crank portion less than the number of rotation center shafts. Connecting rods are connected to each other via idle rotors,
The internal combustion engine according to claim 1 or 2.

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