JP2000055164A - Piston-crank mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the friction load between the slide contacting surfaces of a piston and cylinder of a piston and crank mechanism to perform conversion of reciprocation into rotary motion and vice versa and reduce the wear of the slide contacting surfaces resulting from the friction load and also the loss of transmitted power. SOLUTION: A link mechanism (9, 10, 5, 4) between a piston 1 and crank shaft is configured so that the direction (C9) of a free link 9 whose one end is pivoted by piston parts (1, 6) through a piston pin 8 is identical to the reciprocating direction of the piston 1 (direction of the axis CP of piston) approx. in the middle in the reciprocation of the piston 1 and is dislocated to a minor extent at the upper and the lower dead point, so as to decrease the friction between the slide contacting surfaces D of the piston and cylinder at the middle point where the load maximizes.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piston / crank mechanism used for an automobile engine or the like.

[0002]

2. Description of the Related Art A piston-crank mechanism for converting a reciprocating motion of a piston into a rotary motion started from the invention of a steam engine, and is now adopted also in an automobile engine.
Widespread. This piston and crank mechanism
There is a sliding part between the cylinder and piston, such as the bearing part of the crankpin, where frictional resistance is generated, and severe load fluctuations, frictional force fluctuations and power loss due to power transmission due to power transmission are large, and the transmission efficiency is reduced. It is well known that this is a factor that accelerates the wear of cylinders, pistons, bearings and the like.

[0003] The transmission efficiency has been improved,
To prevent wear of parts such as bearings, materials,
Various improvements have been made to the structure, lubrication, cooling, and the like. However, the conventional piston / crank mechanism basically uses the mechanism shown in FIG. 5, and no epoch-making improvement regarding this mechanism has been made.

The structure of a conventional piston / crank mechanism is as follows.
One cylinder is schematically illustrated in FIG. 5. At the top dead center of the piston 101 (FIG. 5A), immediately before the explosion stroke or the suction stroke of the cylinder 102,
At the bottom dead center (FIG. 5C), immediately before the exhaust stroke or the compression stroke, the piston 101 is in a substantially stationary state, while the explosive force of the other cylinder and the crankshaft 103 and the crank arm integrated therewith. The crankshaft 103 rotates in the rotation direction A by the inertial force with the crankshaft 104. The connecting portions of the crank arm 104 and the connection rod 105, and the connection portions of the connection rod 105 and the piston rod 106 are pivotally supported by the crank pin 107 and the piston pin 108, respectively. Neither side pressure nor frictional force due to the side pressure is applied to the sliding contact surface D between the piston 102 and the piston 102.

On the other hand, at an intermediate point from the top to the bottom of the piston stroke (FIG. 5B), during the explosion stroke, the rotation A of the crankshaft 103 is mainly caused by the piston 10 in FIG.
7, the downward thrust, that is, the explosive force of the cylinder 102. Here, a rotational force is applied from the connection rod 105 to the crank arm 104,
At this time, the axis of the connection rod 105 is largely inclined by θ with respect to the piston rod 106.
Since the piston rod 106 is integrally fixed to the piston 101, a reaction force of a rotational driving force that strongly presses the crank arm 104 by the connection rod 105 is applied to the piston pin 108, and a bending moment is applied to the piston rod 106. As a result, the piston 1
As a result, a large lateral pressure and a frictional force are applied to the sliding contact surface D.

[0006] As described above, the lateral pressure of the sliding portion of the crank pin 107 and the change of the frictional force resulting therefrom in FIGS. 5 (a) to 5 (c) are approximately as shown by PO1 in FIG. a), it is small at the bottom dead center (c) and large at the middle point (b) of the explosion stroke.

In the piston / cylinder suction stroke, the drive side is switched, and the connection rod 105 is driven from the crank arm 104, and the connection rod 105 pushes up the piston rod 106 in the axial direction. Also at this time, due to the inclination θ between the connection rod 105 and the piston rod 106, a lateral pressure and a frictional force associated therewith are applied to the sliding contact surface D. Since the suction resistance is smaller than the driving force of the crank arm 104, the value slightly decreases and becomes Po2 in FIG. 6, but the maximum point at the middle point of the reciprocating stroke of the piston 101 is the same as PO1. is there.

In FIG. 5D, that is, in the exhaust stroke or the compression stroke of the piston 101, the crank arm 104 is moved by the explosive force of another cylinder or the inertia force of the crank shaft 103 or the crank arm 104.
Of the connection rod 10
The sliding part of the crank pin 107, which is the connection part with the 5, is pressed. This pushing force only pushes up the connection rod 105, the piston rod 106, and the piston 101 to exhaust or compress, so that the PO2 is not the same as in the explosion stroke but almost the same as the suction stroke.

As described above, during each of the suction, compression, explosion, and exhaust strokes, the sliding between the piston 101 and the cylinder 102 is performed at the intermediate point (FIGS. 5B and 5D) where the speed of the piston 101 is the highest. The lateral pressure and the frictional force of the contact surface D become maximum as shown in FIG.

[0010]

As described above, in the conventional piston / crank mechanism, the piston 101
At the intermediate point where the speed of the piston 101 is highest, the lateral pressure and the frictional force of the sliding surface D between the piston 101 and the cylinder 102 become maximum, so that the cylinder 102 and the piston 101 sliding on the cylinder 102 are extremely severe. Must withstand the condition. In particular, the middle part of the cylinder 102
Since the speed, lateral pressure and frictional force of 01 are the parts where the maximum force is obtained, the condition is severe.

When the piston / cylinder that has been used for a long time or has seizure is disassembled, the intermediate point C of the cylinder 102 and the sliding surface D of the piston 101 are disassembled as shown in FIG.
It can be seen from the fact that the piston 101 is severely damaged and the speed, lateral pressure and frictional force of the piston 101 are maximum. The speed, side pressure and frictional force of the piston 101 are determined by the piston 101 and the cylinder 10.
In addition to shortening the service life of No. 2, the power of the engine is consumed by unnecessary side pressure and frictional force, which reduces the transmission efficiency of the piston / cylinder mechanism and the engine efficiency.

On the other hand, when the piston 101 reaches the vertical dead center in the reciprocating stroke of the piston 101, the frictional force of the sliding contact surface D between the piston 101 and the cylinder 102 is small, and the braking is not effective. It seems that the crank arm 104 is pushed insignificantly at top dead center and bottom dead center,
By pulling it, a side pressure is applied to the bearing of the crankshaft 103, the crankpin 107, and the piston pin 108 in a shocking manner, so that damage to these parts is unnecessarily accelerated.

When the crankpin which has been used for a long period of time or seized is disassembled, as shown in FIG. 7B, the damaged surface E of the crankpin 107 is concentrated at the angular position where the above-mentioned impact is generated. You can see this fact from The power of the engine is also consumed by this impact force, which lowers the transmission efficiency of the piston / cylinder mechanism and the engine efficiency.

[0014] The present invention solves the above-mentioned problems, and provides a lateral pressure on a sliding contact surface at a midpoint of a piston stroke between a piston and a cylinder.
An object of the present invention is to provide a piston / crank mechanism that has a small frictional force and a small impact force at a top and bottom dead center and can smoothly convert a reciprocating motion of a piston into a rotational motion of a crankshaft.

[0015]

According to a first aspect of the present invention, there is provided a piston-crank mechanism for converting a reciprocating motion of a piston into a rotary motion of a crankshaft. A free link pivotally supported on the piston portion via a piston pin disposed on a central axis of the piston portion, and a free link pivot point at the other end of the free link. An intermediate link mechanism consisting of a plurality of links connected to a crankpin of a crank arm that is rotatable together with the crankshaft and transmitting reciprocating motion of the piston to the crankshaft. Link that surrounds the crankshaft according to the reciprocating sliding stroke of the piston By moving along a predetermined reference trajectory, the free link pivot point is substantially located on the center axis of the piston portion when the piston portion is at least at the midpoint of the reciprocating stroke. I do.

According to a second aspect of the present invention, there is provided a piston-crank mechanism for converting a reciprocating motion of a piston into a rotary motion of a crankshaft. A free link pivotally supported via a piston pin disposed on the central axis of the section, and a cross link pivotally supported at one end by the other end of the free link and at the other end by a crankcase surrounding the crankshaft. And a connection rod, one end of which is pivotally supported at an arbitrary part except a pivot point of the crosslink with the crankcase, and the other end of which is pivotally supported by a crank arm that is rotatable together with the crankshaft. When the part is at the midpoint of its reciprocation, the pivot point between the free link piston and the cross link is Department free link axis, characterized in that substantially coincides with the reciprocating direction of the piston portion.

According to the first and second aspects of the present invention, the lateral pressure between the piston and the cylinder at an intermediate point of the reciprocating stroke of the piston,
The sliding friction is remarkably reduced, the piston slides smoothly, and a slight lateral pressure and a frictional force are generated at the upper and lower dead points, thereby exerting a braking action of the piston.

According to a third aspect of the present invention, there is provided a piston / crank mechanism for converting a reciprocating motion of a piston into a rotating motion of a crankshaft. A free link pivotally supported on the piston portion via a piston pin disposed on the center axis of the piston portion, an idler link having an intermediate point pivotally supported by the other end of the free link, and one end having the idler link. A cross link pivotally supported at one end of the link and the other end pivotally supported on one side of a crankcase surrounding the crankshaft; and a cross link having one end pivotally supported by the other end of the idler link and the other end being the other of the crankcase. One end is pivotally supported at an arbitrary portion except a pivot point between the guide link pivotally supported on the side and the crankcase of the cross link. Has a connection rod pivotally supported by a crank arm that is rotatable together with the crankshaft, and a free link connecting a pivot point of the free link with the piston part and a pivot point of the idler link during a reciprocating stroke of the piston part. The axis is substantially coincident with the reciprocating direction of the piston portion.

According to the third aspect of the present invention, the stroke range in which the free link axis and the reciprocating direction of the piston portion (the direction of the center axis of the piston) coincide with each other is widened, and the transmission efficiency from the piston portion to the crankshaft is further improved. I do.

According to a fourth aspect of the present invention, in the piston / crank mechanism according to the second or third aspect, the length from the pivot point of the cross link to the connection rod to the pivot point of the crankcase is closer to the piston portion. , That is, shorter than the length from the pivot point with the idler link to the pivot point of the crankcase.

According to the fourth aspect of the present invention, the lever-increasing mechanism is constituted, and the driving force for the crankshaft is increased.

[0022]

Embodiments of the present invention will be described below.
This will be described with reference to the drawings.

[First Embodiment] FIG. 1 is an explanatory view showing a first embodiment of a piston / crank mechanism according to the present invention, in which a piston 1 is in contact with an inner diameter of a cylinder 2 so as to be capable of reciprocating sliding. I have. The reciprocating motion of the piston 1 in the cylinder 2 is performed in accordance with the absorption, compression, explosion, and exhaustion of the burned gas of the engine, similarly to the conventional piston-crank mechanism.

Reference numeral 3 denotes a crankshaft, 4 denotes a crank arm, 5 denotes a connection rod, and 6 denotes a piston rod. The crankshaft 3 is rotatably supported by a bearing (not shown), and a crank arm 4 is fixed to the crankshaft 3. A crank pin 7 is provided at the tip of the crank arm 4, and a bearing portion provided at one end of the connection rod 5 is rotatably fitted to the crank pin 7 and pivotally supported.

The piston rod 6 is integrally formed below the piston 1 and forms a piston portion together with the piston 1. A piston pin 8 is provided at the tip of the piston rod 6. Note that the piston rod 6 of the piston portion may be omitted, and the piston pin 8 may be provided directly on the piston 1. These points are the same as those of the conventional piston / crank mechanism.

The piston pin 8 is located at the center axis of the piston 1.
When an external force is applied to the piston 1 via the piston pin 8 in the direction of the central axis CP, the piston 1 is disposed on the central axis CP.
Prevents the application of a rotational moment about an axis perpendicular to the CP. This is because when a rotational moment is applied, unnecessary side pressure is applied to the sliding contact surface between the piston 1 and the cylinder 2.

One end of a free link 9 is pivotally supported on the piston rod 6 via a piston pin 8. The other end of the free link 9 has a cross link 10
Is pivoted (11) at one end. This cross link 1
0 is pivotally supported (13) on one side of a crankcase 12 surrounding the crankshaft 3, and a free link 9 is provided.
The other end of the connection rod 5 is pivotally supported at the free link pivot point 11.

At each of the pivot points 7, 8, 11 and 13,
Since the respective links are swingable with each other, the free link 9, the cross link 10 and the connection rod 5 swing in accordance with the reciprocating sliding of the piston 1 in the cylinder 2, whereby the crank arm 4 The crankshaft 3 is supported by a bearing (not shown) to rotate.

When the piston 1 is located at an intermediate point between the top dead center and the bottom dead center of the reciprocating stroke of the piston 1, as shown in FIG. 1 (b), the pivot point 8 of the free link 9 with the piston rod 6 and the cross link 10 The free link axis C9 connecting the pivot point 11 with
Reciprocating motion direction of piston 1 (Piston central axis CP direction)
It is set to almost match with.

In the first embodiment shown in FIG. 1, the cross link 10 and the connection rod 5 are connected to the piston 1,
6 constitutes an intermediate link mechanism that transmits the reciprocating motion of the crankshaft 6 to the crankshaft 3.

A plurality of piston-cylinder mechanisms shown in FIG. 1 are provided on the crankshaft 3 in the same manner as in a normal multi-cylinder engine, with the phases of the piston 1 and the crank arm 4 shifted.

Next, the operation of the piston / crank mechanism shown in FIG.
The description will be given sequentially along the process of exhausting the burned gas.

FIG. 1 (a) shows a state in which the crank is at the top dead center where the fuel gas shifts from the compression stroke to the explosion stroke, or from the exhausted burned gas to the intake of new fuel gas.

In order to reach this state, the rotational driving force of another piston / crank mechanism (not shown) provided on the same crankshaft 3 or the secondary inertial force caused by the rotational driving by the explosion stroke of the previous stroke The rotation of the crankshaft 3 in the direction A causes the connection rod 5 to be pushed up, the cross link 10 to swing upward with the pivot 13 as a fulcrum, and the piston 1 to be pushed up via the piston rod 6 and the cylinder 2 to be pushed up. Compress fuel gas inside or exhaust burnt gas. By the time the state shown in FIG. 1A, which is the end point of the compression stroke or the exhaust stroke, is reached,
Due to the fast rotation of the crankshaft 3, a large upward speed is given to the piston 1. When the piston 1 comes close to FIG. 1A, the speed is increased by the crank arm 4 and further in the case of the compression stroke. Although the pressure is suppressed by the pressure of the compressed gas, a large load is applied to the pivot points 8, 11, and 7 of each link, which is opposite to that at the time of driving.

By the way, in the vicinity of the top dead center of FIG.
The angle θ formed between the free link axis C9 connecting the shaft and the pivot point 11 with the cross link 10 with the reciprocating direction of the piston 1 (the direction of the center axis CP of the piston) is not 0, but the free link 9
The braking force applied to the piston 1 in the downward direction is inclined by θ from directly below (directly below in the conventional piston-crank mechanism shown in FIG. 5). This inclination causes the piston 1
Receives a rotational moment about an axis perpendicular to the piston center axis CP (about an axis perpendicular to the paper surface), applies a side pressure to a sliding contact surface D with the cylinder 2, and generates a frictional force by sliding (FIG. 6).
PB). Since this frictional force contributes to the braking force, the load on the pivot points 8, 11, and 7 of each link is reduced accordingly.

When the crankshaft 3 further advances in the direction A from FIG. 1 (a) and moves to the explosion stroke or the suction stroke,
The inclination θ of the free link 9 gradually decreases, and the side pressure and the frictional force on the sliding surface D decrease with the inclination θ. In the case of the explosion stroke, the piston 1 strongly pushes down the piston rod 6, the free link 9, the connection rod 5, and the crank arm 4 downward in the figure, and drives the crank shaft 3 to rotate in the direction A. In the case of the suction stroke, the crank arm 4, the connection rod 5, the free link 9, the piston rod 6, and the piston 1 are rotated by the rotation of the crankshaft 3 in the direction A by the driving force or the secondary inertia force of another piston-crank mechanism. Push down.

In either case, the side pressure and frictional force of the sliding surface D are large near the upper fulcrum in FIG. 1A, but at the middle point of the reciprocating stroke of the piston portion (FIG. 1B), The swing of the link 10 about the pivot point 13 with the crankcase 12 (moving along a predetermined trajectory (an arc around the pivot point 13) with respect to the crankcase 12) with respect to the crankcase 12 causes the cross of the free link 9 to cross. The pivot point 11 with the link 10 is approached until it substantially matches the piston center axis CP, and the free link axis C9 substantially matches the reciprocating direction of the piston 1 (the direction of the piston center axis CP). Therefore, in the vicinity of FIG. 1B where the crankshaft 3 is most strongly accelerated, the free link axis C9 of the free link 9 is
, The inclination θ between the free link 9 and the piston rod 6 becomes substantially zero, and the side pressure of the sliding contact surface D between the piston 1 and the cylinder 2 becomes theoretically zero. The frictional resistance disappears and the piston 1
In the vicinity of FIG. 1 (b) where the power is highest, the piston 1 drives the crankshaft 3 very efficiently and smoothly.

As shown in FIG. 1C, the cross link 10 further swings toward the bottom dead center, and the pivot point 11 of the free link 9 with the cross link 10 is separated from the piston center axis CP, and The inclination θ between the link 9 and the piston rod 6 starts to increase, whereby the lateral pressure and the frictional resistance of the sliding contact surface D also increase, and a braking force is generated toward the bottom dead center. Effectively works for reversal.

The state from the bottom dead center in FIG. 1 (c) to the exhaust stroke or the compression stroke to reach FIG. 1 (a) is not shown, but is in the middle of the stroke of accelerating the piston 1 in FIG.
(B) Similarly to the vicinity, the free link axis C9 of the free link 9 is in the reciprocating direction of the piston 1 (the piston center axis CP
Direction), the inclination θ between the free link 9 and the piston rod 6 becomes substantially zero, and the piston 1 and the cylinder 2
And the frictional resistance disappears, and the piston 1 rises efficiently and smoothly without being hindered by the lateral pressure and frictional resistance of the sliding contact portion D. Then, as described above, when approaching the vicinity of the top dead center, the lateral pressure and frictional resistance of the sliding contact surface D increase, and act as a braking force.

As described above, in the embodiment shown in FIG. 1, the side pressure and the frictional resistance of the sliding contact surface D between the piston 1 and the cylinder 2 become zero at the midpoint of the reciprocating stroke of the piston.
At the top dead center and the bottom dead center, the lateral pressure and frictional resistance of the sliding contact surface D are appropriately generated, and the reciprocating motion of the piston 1 can be performed very efficiently and smoothly. The energy loss at the contact surface D is reduced, and the transmission efficiency is improved.

[Second Embodiment] FIG. 2 shows a second embodiment of the present invention.
An embodiment will be described. The second embodiment is the same as the first embodiment except that the pivot point between the cross link 14 and the connection rod 5 is different. Therefore, the same portions as those of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 2, the pivot point 15 between the cross link 14 and the connection rod 5 is closer to the pivot point 13 with the crankcase 12 than the free link pivot point 11 between the cross link 14 and the free link 9. The length L1 from the pivot point 15 of the cross link 14 with the connection rod 5 to the pivot point 13 of the crankcase 12 is from the pivot point 11 with the free link 9 connected to the piston 1 side to the pivot point 13 of the crankcase 12. It is arranged shorter than the length L2.

At the intermediate point of the piston 1, the free link pivot point 11 is at 11b (11d) in FIG. 2, the pivot point 15 is at 15b (15d), and the pivot point 7 is at 7b (7d).
, The piston rod 6 and the free link 9 are aligned on the central axis CP of the piston, and at the top dead center, the pivot point 15 is at 15a, the pivot point 7 is at 7a, and at the bottom dead center,
The pivot point 15 moves to 15c, and the pivot point 7 moves to 7c.

In this embodiment, the movement of the connection rod 5 with respect to the reciprocating movement of the piston 1 is reduced to L1 / L2 as compared with the embodiment of FIG. The force by which the connection rod 5 drives the crank arm 4 increases to L2 / L1. Due to this principle of leverage, in the embodiment of FIG.
The power for rotating the crankshaft 3 is further increased. The states in the steps of intake, compression, explosion, and exhaust are the same as those in FIG.

In the second embodiment shown in FIG. 2, the cross link 14 and the connection rod 5 are connected to the piston 1,
6 constitutes an intermediate link mechanism that transmits the reciprocating motion of the crankshaft 6 to the crankshaft 3.

[Third Embodiment] FIG. 3 shows a third embodiment of the present invention.
An embodiment will be described. This third embodiment is the same as the above-described second embodiment except that the cross link 16 is an L-shaped lever. Therefore, the same portions as those of the first and second embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

Also in the third embodiment, the length L1 from the pivot point 15 of the cross link 14 with the connection rod 5 to the pivot point 13 of the crankcase 12 is different from that of the free link 9 connected to the piston 1 side. It is shorter than the length L2 from the free link pivot point 11 to the pivot point 13 of the crankcase 12, and the force for rotationally driving the crankshaft 3 is further enhanced by the principle of leverage.

At the intermediate point of the piston 1, the pivot point 1
5 is at 15d (15b), the pivot point 7 is at 7d (7b), the piston rod 6 and the free link 9 are aligned on the central axis CP of the piston, and at the top dead center, the pivot point 15 is At 15a, the pivot point 7 moves to 7a, and at the bottom dead center, the pivot point 15 moves to 15c, and the pivot point 7 moves to 7c.

In the third embodiment shown in FIG. 3, the cross link 16 and the connection rod 5 are connected to the piston 1,
6 constitutes an intermediate link mechanism that transmits the reciprocating motion of the crankshaft 6 to the crankshaft 3.

According to the third embodiment, the degree of freedom in the layout of the piston 1 and the crankshaft 3 is increased, and a design in which the crankshaft 3 is largely displaced from the center axis CP of the piston 1 is made possible.

[Fourth Embodiment] FIG. 4 shows a fourth embodiment of the present invention.
An embodiment will be described. In the fourth embodiment, the relationship between the connection rod 5 and the crank arm 4 is the same as in the second embodiment shown in FIG.

In the fourth embodiment, a so-called parallel link is used so that the free link 9 does not deviate from the piston center axis CP during the reciprocating movement of the piston 1.

That is, the center of the idler link 17 is pivotally supported by the lower end of the free link 9 (18), and the right end of the idler link 17 is pivotally supported by one end of the cross link 14 (19).
The other end is pivoted (21) to one end of the guide link 20. The other end of the guide link 20 is pivotally connected to the cross link 14 of the crankcase 12 at the other end.
Is pivoted (22) to the crankcase 12 on the opposite side.

The length of the guide link 20 (the length from the pivot point 21 with the idler link 17 to the pivot point 22 with the crankcase 12) is determined by the length of the cross link 14 (from the pivot point 19 with the idler link 17). Crankcase 1
2), and the length from the free link pivot point 18 of the idler link 17 to the free link 9 to the pivot point 19 to the cross link 14 is equal to the length of the free link 9. The length from the free link pivot point 18 to the pivot point 21 with the guide link 20 is equal to the length. Then, at an intermediate point of the stroke of the piston 1, the cross link 14 and the guide link 20 are connected to the piston center axis CP.
Perpendicular to (the pivot point 19 or 2 with the idler link 17)
The straight line connecting the pivot point 1 and the pivot point 13 or 22 of the crankcase 12 is orthogonal to the piston center axis CP, and the idler link 17 is inclined between them. In the parallel link configured as described above, the idler link 1 is moved over a wide range before and after the middle point of the stroke of the piston 1.
7, the free link pivot point 18 moves along the piston center axis CP.

At the intermediate point of the piston 1, the pivot point 1
5 is at 15d (15b), pivot point 7 is at 7d (7b), at top dead center pivot point 15 is at 15a, pivot point 7 is at 7a, and at bottom dead center pivot point 15 is At 15c, the pivot points 7 move to 7c, respectively.

In the fourth embodiment shown in FIG. 4, the idler link 17, the guide link 20, the cross link 14, and the connection rod 5 form an intermediate link mechanism for transmitting the reciprocating motion of the pistons 1, 6 to the crankshaft 3. Make up.

In this embodiment, the free link axis C9 connecting the pivot point 8 of the free link 9 with the piston rod 6 and the pivot point 18 of the idler link 17 forms a reciprocating motion of the piston 1 over the reciprocating stroke of the piston 1. Since the direction of motion (the direction of the center axis CP of the piston) remains substantially the same, the surface pressure and frictional force applied to the sliding contact surface D between the piston 1 and the cylinder 2 are always very small over a wide stroke range of the piston 1, The braking force due to the lateral pressure and frictional force of the sliding contact surface D near the dead center is weakened, but the transmission efficiency from the piston 1 to the crankshaft 3 is further improved.

As described in detail above, in the piston / crank mechanism of the present invention, the surface pressure and frictional force applied to the sliding contact surface D between the piston 1 and the cylinder 2 are significantly reduced, and energy loss due to this is reduced. Since the transmission efficiency is greatly reduced and the transmission efficiency is improved, a relatively low-power engine can be used. The selectable range of fuel, fuel gas pressure, ignition timing, combustion time, combustion temperature, etc. is also widened, and by making optimal selections, fuel efficiency is reduced, output is improved, and CO, H, C, etc. in exhaust gas are reduced. Can bring effects.

If the principle of "lever" is adopted as in the embodiments of FIGS. 2, 3 and 4, the piston speed is increased, so that idling rotation can be reduced.
Sufficient output can be obtained even with the use of lean fuels and alternative fuels.

In the above-described embodiment, the case of the internal combustion engine has been described. However, it is a matter of course that similar effects can be obtained even if the present invention is applied to another engine.

In the above-described embodiment, the link of the intermediate link mechanism that moves along a predetermined trajectory based on the crankcase surrounding the crankshaft in accordance with the reciprocating sliding stroke of the piston portion is as follows. Although the cross link 10, 14 or 16 pivotally supported by the crankcase is used, for example, the cross link may be guided by a groove cam attached to the crankcase. The movement trajectory of the cross link does not necessarily have to be a circular arc.

[0062]

As described above, according to the present invention, when the piston portion is at or near the midpoint of the reciprocating stroke, the axis of the free link connected to the piston portion and the reciprocation of the piston portion Movement direction (piston center axis
(CP direction) almost coincides with each other. At or near the midpoint of the reciprocating stroke of the piston, the side pressure and sliding friction between the piston and cylinder are significantly reduced, and the piston slides smoothly, At the dead center, a slight lateral pressure and frictional force are generated, and the braking action of the piston is exerted, so that the piston can be smoothly turned up and down, thereby reducing the wear of the piston and the cylinder and improving the transmission efficiency.

The length from the pivot point of the cross link with the connection rod to the pivot point of the crankcase is
If it is shorter than the length to the pivot point with the link connected to the piston part side, a booster mechanism by leverage will be configured, and the driving force on the crankshaft will be stronger,
Even if the output on the driving side of the engine or the like is lowered, smooth rotation of the crankshaft can be maintained.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of a piston-crank mechanism according to the present invention.
(A) is a state at a top dead center, (b) is a state at an intermediate point of a stroke from a top dead center to a bottom dead center, and (c) is a bottom dead center. The state in is shown.

FIG. 2 shows a second embodiment of the piston-crank mechanism according to the present invention.
Explanatory drawing which shows embodiment.

FIG. 3 shows a third example of the piston-crank mechanism according to the present invention.
Explanatory drawing which shows embodiment.

FIG. 4 shows a fourth example of the piston / crank mechanism according to the present invention.
Explanatory drawing which shows embodiment.

5A and 5B are explanatory views showing a conventional piston-crank mechanism, wherein FIG. 5A shows a state at a top dead center, FIG. 5B shows a state at an intermediate point of a stroke from top dead center to bottom dead center, and FIG. )
The state at the bottom dead center, (d) shows the state at the middle point of the stroke from the bottom dead center to the top dead center.

FIG. 6 is an explanatory diagram showing changes in side pressure and frictional force applied to a crank rod of a piston / crank mechanism during a stroke, comparing a conventional one and the present invention.

FIG. 7 is a perspective view showing a worn state of an engine using a conventional piston / crank mechanism.
The worn state of the cylinder, (b) shows the worn state of the crankpin and the bearing fitted thereto.

[Explanation of symbols]

Reference Signs List 1 piston 2 cylinder 3 crankshaft 4 crank arm 5 connection rod 6 piston rod 7 crank pin (pivot point between connection rod 5 and crank arm 4) 8 piston pin (piston rod 6 and free link 9)
9 Free link 10 Cross link 11 Free link pivot point (free link 9 and cross link 10 pivot point) 12 Crankcase 13 Pivot point (cross link 10 (16) and crankcase 12) 14 Cross link 15 Pivot point (between cross link 16 and connection rod 5) 16 Cross link 17 Idler link 18 Free link pivot point (pivot point between free link 9 and idler link 17) 19 Pivot point (cross link 14 and idler link 1)
7) 20 guide link 21 pivot point (idler link 17 and guide link 2)
0) 22 pivot point (guide link 20 and crankcase 12)
Center axis of CP piston C9 free link axis D sliding surface (between piston 1 and cylinder 2) L1 pivot point 15 of cross link 14 (16) with connection rod 5 to pivot point 13 of crankcase 12
L2 Length from the pivot point 11 of the cross link 14 (16) to the free link 9 (or the pivot point 19 to the idler link 17) to the pivot point 13 of the crankcase 12

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[Procedure amendment]

[Submission date] June 9, 1999 (1999.6.9)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 4

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

[0015]

According to a first aspect of the present invention, there is provided a piston-crank mechanism for converting a reciprocating motion of a piston into a rotary motion of a crankshaft. A free link pivotally supported on the piston portion via a piston pin disposed on a central axis of the piston portion, and a free link pivot point at the other end of the free link. An intermediate link mechanism comprising a plurality of links connected to a crankpin of a crank arm that is rotatable together with the crankshaft and transmitting reciprocating motion of the piston to the crankshaft . Around the crankshaft
One end is pivotally supported by the rank case to reciprocate the piston.
The transmitted link, the pivoted cross link, and the above
Any except for pivot point with crosslink crankcase
One end is pivotally supported on the part and the other end is pivoted on the crank arm.
A supporting connection rod, wherein the free link pivot point is substantially on the center axis of the piston portion when the piston portion is at least at an intermediate point of the reciprocating process.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

Further, the invention of claim 4 is the first or second aspect of the present invention.
Other in piston-crank mechanism according to 3, the length from the pivot point of the connecting rod of the cross-linked to the pivot point of the crank case is shorter than the length to the pivot point of the link connected to the piston portion It is characterized by being arranged.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0030

[Correction method] Change

[Correction contents]

In the first embodiment shown in FIG. 1, the cross link 10 and the connection rod 5 are connected to the piston 1,
An intermediate link mechanism for transmitting the reciprocating motion of the motor 6 to the crankshaft 3 is formed. And free link 9
It is a link that transmits a ton of reciprocating motion.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0045

[Correction method] Change

[Correction contents]

In the second embodiment shown in FIG. 2, the cross link 14 and the connection rod 5 are connected to the piston 1,
An intermediate link mechanism for transmitting the reciprocating motion of the motor 6 to the crankshaft 3 is formed. And free link 9
It is a link that transmits a ton of reciprocating motion.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction contents]

[Third Embodiment] FIG. 3 shows a third embodiment of the present invention.
An embodiment will be described. This third embodiment is the same as the above-described second embodiment except that the cross link 14 is an L-shaped lever. Therefore, the same portions as those of the first and second embodiments are denoted by the same reference numerals, and detailed description thereof will be omitted.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction contents]

In the third embodiment shown in FIG. 3, the cross link 14 and the connection rod 5 are connected to the piston 1,
6 constitutes an intermediate link mechanism that transmits the reciprocating motion of the crankshaft 6 to the crankshaft 3. And free link 9
It is a link that transmits a ton of reciprocating motion.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0056

[Correction method] Change

[Correction contents]

In the fourth embodiment shown in FIG. 4, the idler link 17, the guide link 20, the cross link 14, and the connection rod 5 form an intermediate link mechanism for transmitting the reciprocating motion of the pistons 1, 6 to the crankshaft 3. Make up. And the idler link 17 is a piston
It is a link that transmits the reciprocating motion of.

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0061

[Correction method] Change

[Correction contents]

In the above-described embodiment, the link of the intermediate link mechanism that moves along a predetermined trajectory based on the crankcase surrounding the crankshaft in accordance with the reciprocating sliding stroke of the piston portion is as follows. Although the crosslinks 10 and 14 pivotally supported by the crankcase are used, for example, the crosslink may be guided by a groove cam attached to the crankcase. The movement trajectory of the cross link does not necessarily have to be a circular arc.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] Explanation of sign

[Correction method] Change

[Correction contents]

[Description of Signs] 1 piston 2 cylinder 3 crankshaft 4 crank arm 5 connection rod 6 piston rod 7 crank pin (connection rod 5 and crank arm
8 Piston pin (piston rod 6 and free link 9)
9 Free link 10 Cross link 11 Free link pivot point (Free link 9 and cross link)
Pivot point of link 10) 12 Crank case 13 pivot point (crosslink)10And crankcase 12
14) Crosslink15 pivot point (cross link 14 and connection rod
With 5) 17 idler link  18 Free link pivot point (Free link 9 and idler
-Pivot point with link 17) 19 Pivot point (cross link 14 and idler link 1)
7) 20 guide link 21 pivot point (idler link 17 and guide link 2)
0) 22 pivot point (guide link 20 and crankcase 12)
Center axis of CP piston C9 Free link axis D Sliding contact surface (between piston 1 and cylinder 2) L1 Cross link14Pivot with connection rod 5
Length from fulcrum 15 to pivot 13 of crankcase 12
Sa L2 cross link14Pivot point 1 with free link 9
1 (or pivot point 19 with idler link 17)
To the pivot point 13 of the crankcase 12

[Procedure amendment 12]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

FIG. 2

[Procedure amendment 13]

[Document name to be amended] Drawing

[Correction target item name] Figure 3

[Correction method] Change

[Correction contents]

FIG. 3

Claims (4)

[Claims] 1. A piston / crank mechanism for converting a reciprocating motion of a piston into a rotary motion of a crankshaft, comprising: a piston portion reciprocatingly sliding in a cylinder; and a piston pin disposed on the piston portion at a center axis of the piston portion. And a free link pivotally supported via a free link, and connected to a free link pivot point at the other end of the free link, and connected to a crankpin of a crank arm that is rotatable together with a crankshaft, thereby reciprocating the piston. An intermediate link mechanism consisting of a plurality of links that transmits to the crankshaft, wherein at least one link of the intermediate link mechanism is based on the crankcase surrounding the crankshaft according to the reciprocating sliding stroke of the piston portion. By moving along a predetermined trajectory, the piston part can reduce its reciprocating stroke. Even when it is in an intermediate point, free-link pivoting point is, the piston-crank mechanism, characterized in that it has to come to the center axis of the substantially piston unit. 2. A piston / crank mechanism for converting a reciprocating motion of a piston into a rotational motion of a crankshaft, wherein a piston portion reciprocally slides in a cylinder, and a piston pin disposed on the piston portion at a center axis of the piston portion. A free link pivotally supported via a link, one end of which is pivotally supported by the other end of the free link, and the other end pivotally supported by a crankcase surrounding a crankshaft; and a crankcase of the crosslink. A connection rod pivotally supported at one end at an arbitrary position other than the pivot point and the other end pivotally supported by a crank arm rotatable together with the crankshaft, and a piston portion is located at an intermediate point of the reciprocating stroke. When the free link axis connecting the pivot point of the free link to the piston and the pivot point of the cross link is Piston-crank mechanism, characterized in that substantially coincides with the direction of motion. 3. A piston / crank mechanism for converting a reciprocating motion of a piston into a rotational motion of a crankshaft, wherein a piston portion reciprocally slides in a cylinder, and a piston pin disposed on the piston portion at a central axis of the piston portion. A free link pivotally supported through a shaft; an idler link having an intermediate point pivotally supported by the other end of the free link; and a crankcase having one end pivotally supported by one end of the idler link and the other end surrounding a crankshaft. A cross link pivotally supported on one side of the guide link; one end pivotally supported by the other end of the idler link, and the other end pivotally supported by the other side of the crankcase; and a crankcase of the cross link. One end is pivotally supported at an arbitrary part except for the pivot point, and the other end is pivotally supported by a crank arm that is rotatable together with the crank shaft. The free link axis connecting the pivot point of the free link with the piston portion and the pivot point of the idler link during the reciprocating stroke of the piston portion substantially coincides with the reciprocating direction of the piston portion. Characteristic piston-crank mechanism. 4. The length from the pivot point of the cross link with the connection rod to the pivot point of the crankcase,
4. The piston / crank mechanism according to claim 2, wherein the length is shorter than a length up to a pivot point with a link connected to the piston portion.