JPH06137175A - Variable compression ratio device for engine - Google Patents

Abstract

PURPOSE:To achieve sure action of variable compression ratio by providing an eccentric sleeve in a small end part of a connecting rod, utilizing its pendulum motion to rotate the eccentric sleeve, and also determining compression ratio by changing a tilt angle of the connecting rod, in a variable compression ratio device for an engine. CONSTITUTION:In this constitution, two lock pins 7 having a predetermined opening angle are provided in a lower internal wall 1a of a piston pin bearing part of a piston 1, a through hole 9 and a sleeve pin 10 opposed to a flange part 5a are provided in the hanging flange part 5a of an eccentric sleeve 5, a connecting rod pin 11 opposed to connecting rods 3 is provided in the connecting rod 3, and a connecting rod driving mechanism A for actuating the piston 1, eccentric sleeve 5 and the connecting rod 3 so as to be fixed or released to/from each other, by advancing/retracting the connecting rod 3, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable compression ratio device for an engine.

[0002]

2. Description of the Related Art Conventionally, in a gasoline engine, the compression ratio is reduced when the engine is under high load to prevent knocking, and the compression ratio is increased when the engine is under low load to improve fuel efficiency. A variable compression ratio device for an engine is proposed in which the compression ratio is reduced in the high speed region of the engine to reduce friction and the compression ratio is increased in the low speed region to improve fuel efficiency.

As such a variable compression ratio device, for example, a sub-chamber or a sub-cylinder communicating with the combustion chamber is provided and the height thereof is adjusted to vary the compression ratio, or the length of the connecting rod is set to a small end portion. Alternatively, a means such as adjusting at the large end to change the compression ratio is adopted. Then, in the case of adjusting the length of the connecting rod at the small end, an eccentric sleeve eccentric to the inner circumference and the outer circumference is interposed between the small end and the piston pin, and at the large end. For adjusting, between the big end and the crankshaft,
By interposing an eccentric sleeve similar to the above, the eccentric position of the eccentric sleeve is changed to change the vertical stroke of the piston to change the compression ratio.

FIG. 18 is a side view of a connecting rod showing an example of a conventional example in which an eccentric sleeve is provided at the large end.
In FIG. 18, 1 is a piston, 2 is a piston pin, 3 is a connecting rod, 4 is a crankpin of a crankshaft, and the large end portion 3 of the connecting rod 3 is shown.
b and the crank pin 4 are connected via an eccentric sleeve 5, and a stopper pin (not shown) provided on the connecting rod 3 is locked at a different predetermined position of the eccentric sleeve 5 to change the eccentric position. Sleeve 5
The compression ratio is adjusted by changing the fixing interval between the crank pin 4 and the piston pin 2 according to the difference in the thickness of the peripheral wall portion.

That is, the stopper pin is locked to the eccentric sleeve 5 by rotating the eccentric sleeve 5. The rotation of the eccentric sleeve 5 is caused by the centrifugal force due to the rotation of the large end portion or the eccentric sleeve itself. The inertial force and the combustion pressure applied to the connecting rod are used. Further, although not particularly shown, even in the case where the eccentric sleeve is provided at the small end portion, the eccentric sleeve is interposed between the small end portion 3a of the connecting rod 3 and the piston pin 2, and the crank pin 4 and The fixed interval of the piston pin 2 is changed.

[0006]

However, in the conventional configuration in which the eccentric sleeve is rotated by the inertial force and combustion pressure of the engine, the rotational speed of the eccentric sleeve is changed by the change of the operating condition of the engine. Therefore, it is difficult to lock the stopper pin,
In addition, it is difficult to confirm when the compression ratio has been switched even if a compression ratio switching command is issued.Therefore, the compression ratio can be reliably switched regardless of whether the eccentric sleeve is provided at the large end or the small end of the connecting rod. There is a common problem that things are difficult.

The present invention was devised in view of the above problems. An eccentric sleeve is provided at the small end of the connecting rod, and the eccentric sleeve is rotated by utilizing the pendulum motion of the connecting rod. By changing the locking position of the eccentric sleeve and the lock pin of the piston according to the change of the inclination angle, it is possible to reliably switch the compression ratio without being affected by the change of the operating condition of the engine. Another object of the present invention is to provide a variable compression ratio device for an engine.

[0008]

Therefore, in the variable compression ratio device for an engine according to claim 1 of the present invention, an eccentric sleeve is rotatably interposed between the small end portion of the connecting rod and the piston pin, A variable compression ratio device for an engine, wherein the eccentric sleeve and the piston pin are fixed at a predetermined position so that the compression ratio in the combustion chamber can be varied. Has a predetermined opening to the left and right with respect to the central vertical line, and two lock pins on the same circumference with respect to the axial center of the piston pin are urged inward of the piston to horizontally The eccentric sleeve is provided and is fitted into the piston pin and rotated by a pendulum motion of the connecting rod, and the two locks are provided on a flange portion that is suspended from a part of the eccentric sleeve. And a horizontal through hole that can individually face the connecting rod, and the side of the small end of the connecting rod sandwiches the collar when the connecting rod is in the first inclined position. It opposes one of the lock pins, and opposes the other lock pin across the collar when the connecting rod is in a second incline position between the first incline position and the central vertical line. A connecting rod pin is provided, and when a high compression command is issued, the connecting rod pin is pushed out into the through hole that aligns when the connecting rod is in the first inclined position, and the connecting rod is in the second inclined position. Sometimes the connecting rod pin is pulled out, and at the time of a low compression command, the connecting rod is connected to the through hole aligned when the connecting rod is in the second tilt position. Extruding the Ddopin, so pull the connecting rod pin when said connecting rods is in the first tilted position, is characterized in that connecting rod pin drive mechanism for driving the connecting rod pin is provided.

Further, in a variable compression ratio device for an engine according to a second aspect of the present invention, the connecting rod pin drive mechanism is embedded in the connecting rod, and the piston portion attached to the connecting rod pin and the connecting rod pin drive mechanism are embedded in the connecting rod pin. A fluid pressure type cylinder mechanism having two fluid chambers partitioned by a piston part, and also embedded in the connecting rod,
A fluid pressure switching mechanism for switching a fluid pressure state to both fluid chambers of the fluid pressure type cylinder mechanism to a high pressure state or a low pressure state;
It is characterized in that the circuit drawn out from the fluid pressure switching mechanism is provided with a fluid pressure generating portion for generating a high pressure fluid and a low pressure fluid.

Further, in a variable compression ratio device for an engine according to a third aspect of the present invention, the fluid pressure generating portion is provided at a large end portion of the connecting rod, and the fluid pressure generating portion is attached to the connecting rod along with the swinging motion of the connecting rod. It is characterized in that it is configured as a fluid pressure generating portion for alternately supplying high hydraulic pressure and low hydraulic pressure to one side and the other side between the connecting rod and the crank pin by the rotation of the crank pin.

In the variable compression ratio device for an engine according to claim 4 of the present invention, the fluid pressure generating portion is provided between the large end portion of the connecting rod and the crank pin, and the fluid pressure switching portion is provided. A pair of left and right arcuate grooves that communicate with the mechanism and a pair of oil passages that are provided from the inside of the crank pin toward the outside and that face each other and can communicate with the pair of arcuate grooves. By the rotation of the crank pin, a high fluid pressure from the oil passage on one side and a low fluid pressure from the oil passage on the other side are alternately generated in the arcuate groove on one side and the passage on the other side. It is characterized by being configured as follows.

Further, a variable compression ratio device for an engine according to a fifth aspect of the present invention is provided with a fluid pressure generating space portion provided inside the connecting rod and arranged along the axial direction of the connecting rod. A mass body fitted in the space portion in a floating state, and by fitting the mass body in a floating state into the space portion, both ends of the mass body in the space portion A pair of fluid pressure chambers facing each other are formed, and by the vertical movement of the connecting rod, a high pressure is generated in the fluid pressure chamber on the destination side of the mass body, and a side opposite to the destination side of the mass body. The fluid pressure chamber is configured to generate low pressure.

According to a sixth aspect of the present invention, in the variable compression ratio device for an engine according to the present invention, the eccentric sleeve collar portion is provided with a sleeve pin slightly shorter than a length of the through hole in the through hole to lock the lock. The pin and the connecting rod pin are opposed to each other via the sleeve pin.

[0014]

In the above-described variable compression ratio device for an engine according to claim 1 of the present invention, the connecting rod reciprocates up and down by the operation of the engine and also performs a pendulum motion with the small end as a fulcrum. Is the first
When the connecting rod is in the inclined position, the connecting rod pin faces the one lock pin across the sleeve pin (through hole) of the eccentric sleeve collar, and when the connecting rod is in the second inclined position, the connecting rod pin is connected. The grod pin faces the other lock pin across the sleeve pin (through hole) of the eccentric sleeve collar.

At the time of the high compression ratio command, the connecting rod pin drive mechanism pushes the connecting rod pin into the through hole aligned when the connecting rod is in the first inclined position, and the connecting rod moves to the second inclined position. The connecting rod pin is driven so that the connecting rod pin is pulled out from the through hole when in the position.

Further, at the time of the low compression ratio command, the connecting rod pin drive mechanism pushes the connecting rod pin into the through hole aligned when the connecting rod is in the second tilted position, and the connecting rod has the first tilted position. The connecting rod pin is driven so that the connecting rod pin is pulled out from the through hole when in the position.

Further, in the variable compression ratio device for an engine according to claim 2 of the present invention, the connecting rod pin drive mechanism comprises a fluid pressure type cylinder mechanism, a fluid pressure switching mechanism, and a fluid pressure generating portion. By switching the pressure switching mechanism, the fluid pressure cylinder mechanism is operated so as to push out or retract the connecting rod pin. Then, this fluid pressure type cylinder mechanism is operated by the high pressure fluid generated in the fluid pressure generating portion.

In the variable compression ratio device for an engine according to claim 3 of the present invention, a high hydraulic pressure and a low hydraulic pressure are generated in the fluid generating portion in accordance with the movement of the connecting rod. Further, in the variable compression ratio device for an engine according to claim 4 of the present invention, due to the rotation of the clamp pin accompanying the movement of the connecting rod, the high hydraulic pressure from the oil passage on one side of the crank pin and the oil pressure from the oil passage on the other side are generated. The low hydraulic pressure is applied alternately to the arcuate groove on one side and the arcuate groove on the other side.

Further, in the variable compression ratio device for an engine according to claim 5 of the present invention, the mass body in a floating state in the fluid pressure generating space of the fluid pressure generating portion has a mass pair associated with the reciprocating motion of the connecting rod. By moving up and down, high hydraulic pressure is generated alternately on the moving direction side of the mass body and low hydraulic pressure is generated on the moving rear direction side of the mass body. Further, in the variable compression ratio device for an engine according to claim 6 of the present invention, since the sleeve pin is interposed between the lock pin and the connecting rod pin, both of the lock pin and the connecting rod pin can be moved by a small amount of movement. Transfer the movement to the pin.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 to 17 show an embodiment of a variable compression ratio device for an engine according to the present invention, and FIG. A cross-sectional view of the connecting rod portion, FIG.
II-II line side view of FIG. 3, FIG. 3 is an overall configuration diagram of the present device, FIG. 4 is an enlarged sectional view of a fluid pressure switching mechanism of the present device,
5 is a cross-sectional view of the fluid pressure generating portion of the present device, FIG. 6 is an operation explanatory diagram of the fluid pressure generating portion according to FIG. 5, FIG. 7 is a hydraulic pressure supply circuit diagram of the present device, and FIGS. FIG. 9 is a side view of each pin portion showing the operating state of the apparatus, which corresponds to FIG.
FIG. 11 is a cross-sectional view taken along the line X-IX of FIG.
FIG. 13 is a cross-sectional view taken along the line XI of FIG.
FIG. 15 is a sectional view taken along the line XIII in FIG.
FIG. 16 is a sectional view taken along the line XV, FIG. 16 is a high / low compression ratio region diagram showing a high compression ratio region and a low compression ratio region of the engine, and FIG. 17 is a connecting rod portion showing another example of the fluid pressure generation unit. It is a sectional view, and in FIGS. 1 to 17, the same reference numerals as those in FIG.

In FIG. 5, in order to clarify the drawing, the cross-sectional chain line of the connecting rod is omitted, and in FIG. 17, the eccentric sleeve and the piston pin are omitted, and the drawing is omitted. For convenience, the fluid pressure switching mechanism is set to 90
Rotated and illustrated. Now, in FIGS. 1 and 3, 1
Is a piston, 2 is a piston pin mounted on the inner diameter of the piston 1, and the small end 3a of the connecting rod 3 is rotatably connected to the piston pin 3 via an eccentric sleeve 5.

As shown in FIGS. 1 to 3, the center of the bearing hole into which the piston pin 2 is inserted (the shaft of the piston pin 2 is formed in the lower inner wall of the bearing portion 1a that pivotally supports the piston pin 2 of the piston 1). The two lock pins 6 and 7 are located on the same circumference with respect to the center), and across the vertical center line v of the bearing hole (the axial center of the piston pin 2) with a required opening on the left and right. It is installed horizontally inward and is biased inward by springs 8 on the back.

The required opening mentioned here is an opening that coincides with the opening of the inclination angle of the connecting rod 3 due to the pendulum motion, and for example, the connecting rod 3
When the tilt angle difference due to the pendulum motion is 40 degrees at the maximum, the two lock pins 6 and 7 are opened to the left and right with the bearing hole, that is, the vertical center line v of the piston pin 2, sandwiched by 20 degrees each. Both lock pins 6 and 7 are arranged at symmetrical positions open at 40 degrees. It should be noted that the two lock pins 6 and 7 are opened to the left and right with the bearing hole, that is, the vertical center line v of the piston pin 2, sandwiched by less than 20 degrees (however, it is better not to be less than 20 degrees). Thus, both lock pins 6 and 7 may be arranged at symmetrical positions opened by an angle smaller than 40.

Then, the piston pin 2 is
An eccentric sleeve 5 in which an inner circumference circle and an outer circumference circle are eccentrically fitted is rotatably fitted in the eccentric sleeve 5. One horizontal through hole 9 is provided in the collar portion 5a, which individually opposes both lock pins 6 and 7 and allows the lock pins 6 and 7 to enter at the respective opposing positions. Are formed.

Further, a sleeve pin 10 which is slightly shorter than the length of the through hole 9 is slidably fitted in the through hole 9. Further, from the outer circumference of the eccentric sleeve 5, a shaft hole (no reference numeral) of the small end portion 3a of the connecting rod 3 is rotatably fitted, and the tip end is inside the connecting rod small end portion 3a. A connecting rod pin (hereinafter referred to as a connecting rod pin, if necessary) 11 that is in contact with 10 and can face both lock pins 6 and 7 is provided so as to be able to move forward and backward in the horizontal direction. When the sleeve pin 10 and the connecting rod pin 11 face each other, they are arranged in a straight line.

The lock pins 6 and 7 and the sleeve pin 1
0 and the connecting rod pin 11 are formed to have substantially the same thickness, and when they are aligned with each other, they can enter the hole side of the mutually adjacent pins. Further, a connecting rod pin drive mechanism A is embedded in the inside of the connecting rod 3, and this connecting rod pin drive mechanism A has a connecting rod pin 11 built therein and is located in front of the piston portion 11a formed at the base thereof. A fluid pressure type cylinder mechanism B for moving the connecting rod pin 11 forward and backward by applying a hydraulic pressure to the rear side, and a fluid pressure switching mechanism for switching the oil passage applied to the front or rear of the piston portion 11a by a high compression ratio command or a low compression ratio command. C and a fluid pressure generating portion D for generating a high hydraulic pressure applied to the piston portion 11a. These portions B, C, D are connected and connected by oil passages 12, 12 ', 13, 13'. .

Therefore, as shown in FIG. 1, when the lock pin 7, the sleeve pin 10 and the connecting rod pin 11 face each other in a straight line and the connecting rod pin 11 is retracted, the lock pin 7 is moved by the spring 8 Is pushed into the through hole 9 of the collar portion 5a of the eccentric sleeve 5 to lock and fix the piston 1 and the eccentric sleeve 5, while the connecting rod pin 11 is retracted and eccentric to the connecting rod 3. The sleeve 5 is not locked and is rotatable.

By the way, as will be described later in detail, the locked state between the piston 1 and the eccentric sleeve 5 by the lock pin 7 shown in FIG. 1 indicates a state in which the engine is operating in a fixed state with a high compression ratio. This corresponds to FIGS. The lock state of the piston 1 and the eccentric sleeve 5 by the lock pin 6 corresponds to FIGS. 14 and 15 showing a state in which the engine is fixed and operated in the low compression ratio state.

Further, when the connecting rod pin 11 is aligned with the sleeve pin 10 and the lock pin 7 and the connecting rod pin 11 is retracted, the fluid pressure switching mechanism is provided behind the piston portion 11a of the connecting rod pin 11. C
When a high hydraulic pressure is applied from the fluid pressure generating portion D via the above, the connecting rod pin 11 is pushed out. Then, the tip of the connecting rod pin 11 enters the through hole 9 and pushes the sleeve pin 10, and the sleeve pin 10 pushes the lock pin 7 and pushes it out of the through hole 9, whereby the connecting rod 3 and the eccentric sleeve 5 are It is locked and fixed, and the eccentric sleeve 5 and the piston 1 are unlocked so as to be rotatable (see FIG. 13).

However, when the high hydraulic pressure is applied in front of the piston portion 11a of the connecting rod pin 11 in such a locked state, the connecting rod pin 11 retracts and the connecting rod 3 and the eccentric sleeve 5 become rotatable, The eccentric sleeve 5 and the piston 1 are fixed (see FIG. 15). Further, when the eccentric sleeve 5 and the connecting rod 3 are fixed, and the pendulum motion of the connecting rod 3 causes the connecting rod 3 and the eccentric sleeve 5 to rotate together and reach the position of the lock pin 6 (see FIG. 8). When the high hydraulic pressure is applied to the rear of the piston portion 11a, the connecting rod pin 11 pushes the sleeve pin 10 into the through hole 9 to fix the connecting rod 3 and the eccentric sleeve 5, and the eccentric sleeve 5 and the piston 1 are separated from each other. It is designed to be rotatable (see FIG. 9).

However, when the above-mentioned high pressure is applied to the front of the piston portion 11a of the connecting rod pin 11 in this locked state, the connecting rod pin 11 retracts, the connecting rod 3 and the eccentric sleeve 5 become rotatable, and the eccentric sleeve 5
The piston 1 is fixed (see FIG. 11). By the way, as described above, the lock pins 6, 7 and the sleeve pin 10 and the connecting rod pin 11 can be pushed into each other and enter the adjacent holes to be locked. This is performed because the length is slightly shorter than the length of the through hole 9, and the spring 8 for urging the lock pins 6, 7 is
8 and the high hydraulic pressure applied to the front or rear of the piston portion 11a of the connecting rod pin 11 is used.

In addition, the locking and disengaging modes of the lock pins 6 and 7, the sleeve pin 10, and the connecting rod pin 11 are as follows: when the engine has a high compression ratio command, when the engine has a high compression ratio fixed, and when the engine has a low compression ratio command. When the low compression ratio is fixed, or when the high or low compression ratio command is issued until it is fixed, the combination changes in various ways.
These will be described in detail in the section of operation explanation.

Next, the respective parts B, C and D constituting the connecting rod pin drive mechanism A will be described in detail with reference to FIGS. 1 and 4 to 6. First, the fluid pressure cylinder mechanism B will be described.
Is provided with a fluid chamber 14 slidably accommodating the piston portion 11a attached to the base portion of the connecting rod pin 11,
The front chamber 1 in which the fluid chamber 14 is partitioned by the piston portion 11a
It is divided into 4a and a rear chamber 14b.

A front chamber 14a and a rear chamber 14b of the fluid chamber 14
And the fluid pressure switching mechanism C communicates with the fluid pressure switching mechanism C via the oil passages 12 ′ and 12, respectively, and when the hydraulic pressure from the fluid pressure switching mechanism C is applied to the front chamber 14 a, the connecting rod pin 11 is retracted to connectin. When retracted into the rod 3 and hydraulic pressure is applied to the rear chamber 14b, the connecting rod pin 11 moves forward and its tip is pushed out from the connecting rod 3.

Further, in the fluid pressure switching mechanism C, as shown in FIG. 4, a switching element 17 biased by a spring 16 is installed in the switching chamber 15 so as to slide horizontally. This interior state is configured so that the switching element 17 slides without being affected by the inertial force due to the pendulum motion and the vertical motion of the connecting rod 3 as much as possible. Further, the switching element 17 is formed with two upright passages 18 and 20 vertically penetrating the inside thereof and two inclined passages 19 and 21 also vertically penetrating the inside thereof, and the upper and lower ends of the respective passages are formed. Are opened in lateral grooves a, b, c, d and e, f, g, h formed by four lines on the upper and lower surfaces of the switching element 17, respectively.

That is, from the right side of the switching element 17, the upper first lateral groove a and the lower first lateral groove e are connected to the first upright passage 18.
The upper third lateral groove c and the lower third lateral groove g are connected by
It is connected by the second upright passage 20, and the upper second lateral groove b and the lower fourth lateral groove h are connected by the second inclined passage 21 and the upper fourth lateral groove d and the lower 2 The second lateral groove f is connected by the first inclined passage 19.

In this case, the first upright passage 18 and the second upright passage 20 may be formed on the same cross section,
The first inclined passage 19 and the second inclined passage 21 are formed on different cross sections with respect to the first and second upright passages 18 and 20, respectively. Therefore, when the switching element 17 is at the position shown in FIG. 4, the upright passages 18, 2 connecting the lateral grooves a-e and c-g are connected.
The oil passage 12-13 and the oil passages 12'-13 'are communicated with each other by 0, and when the switching element 17 moves to the right, the oil is fed by the inclined passages 19 and 21 connecting the lateral grooves df and bh. Road 1
2'-13 and the oil passage 12-13 'are communicated with each other, and by moving the switching element 17 left and right, the oil passage 12,
The connection between 12 'and the oil passages 13 and 13' can be switched.

Further, the fluid pressure generating portion D is formed between the large end portion 3b of the connecting rod 3 and the crank pin 4. That is, as shown in FIGS. 1, 3, and 5, two arcuate grooves 36 and 37 along the circumferential direction are provided on the inner peripheral surface of the shaft hole of the large end portion 3b at substantially left-right symmetrical positions, and Two arcuate grooves 36, 37 are provided in the pin 4.
And a pair of left and right oil passages 38 and 39 that can face each other and communicate with each other are formed so as to open outward.

The one arcuate groove 36 is communicated with the fluid pressure switching mechanism C via the oil passage 13 ′ in the connecting rod 3, and from the fluid pressure switching mechanism C via the oil passage 13 the other arcuate groove 37. Is in communication with. In addition, the pair of oil passages 3
The inner sides of the oil passage 8 and the oil passage 39 are connected to the oil passages 41 and 42 in the crankshaft 25, respectively.

Therefore, when a high oil pressure is applied to one oil passage 38, this high oil pressure is passed from the one arc groove 36 to the oil passage 1.
3 ′ and the fluid pressure switching mechanism C to reach the fluid chamber 14 of the fluid pressure cylinder mechanism B, and further from the fluid chamber 14 through the fluid pressure switching mechanism C and the oil passage 13 to the other arcuate groove 37.
The oil passage 39 is extracted from the other oil passage 39.

When the connecting rod 3 moves upward while inclining to the right (compression stroke and exhaust stroke of the combustion chamber), high oil pressure is applied to one oil passage 38 and low pressure is applied to the other oil passage 39. When the connecting rod 3 moves downward while inclining to the left (intake stroke and expansion stroke of the combustion chamber), the other oil passage 39
A high hydraulic pressure is applied to one of the oil passages 38 so as to be on the pressure relief side.

As described above, the oil passage 38 or 39
The high hydraulic pressure applied by the high hydraulic pressure that is ejected outward by the centrifugal force associated with the rotation of the crank pin 4 or the high hydraulic pressure that is supplied from the hydraulic source (not shown) through the crankshaft 25. In the latter case, the supply high hydraulic pressure and the centrifugal hydraulic pressure can be combined to apply a higher hydraulic pressure.

Therefore, the fluid pressure generator D is shown in FIG.
As shown in FIG. 3, while the oil passage 38 communicates with the arc-shaped groove 36 on one side, that is, the oil passage 38 rotates from the position shown by the dotted line to the position shown by the solid line, and goes away from the arc-shaped groove 36. Up to the above, high hydraulic pressure is sent from the fluid pressure switching mechanism C to the fluid pressure cylinder mechanism B via the oil passage 13 ', and at the same time, the oil passage 39 is communicated with the arcuate groove 37 on the other side. The hydraulic pressure from the fluid pressure type cylinder mechanism B and the fluid pressure switching mechanism C is sent out through the oil passage 13.

On the contrary, while the oil passage 38 communicates with the arcuate groove 37 on the other side and the oil passage 39 communicates with the arcuate groove 36 on the one side, the oil passage 13-fluid pressure The hydraulic pressure is sent through a path of switching mechanism C-fluid pressure cylinder mechanism B-fluid pressure switching mechanism C-oil passage 13 '. Then, such an operation is performed by the rotation of the crank pin 4.
The high hydraulic pressure and the low hydraulic pressure are alternately applied to the one circular arc groove 36 and the other circular arc groove 37.

Further, the oil passage 24 for sending the high compression ratio command or the low compression ratio command to the fluid pressure switching mechanism C has the arcuate groove 3
Since it is connected to the oil passage 40 on the circumference different from 6 and 37, the operation of another system is controlled regardless of the above operation. As a result, the switching element 17 of the fluid pressure switching mechanism C moves to the left or right according to the high compression ratio command or the low compression ratio command sent from the oil passage 24, and the fluid pressure switching mechanism C moves between the oil passages 13 ′ and 13 and the oil passages 12 ′ and 12. When the connection is switched, the high hydraulic pressure from the fluid pressure generator D causes the front chamber 14a of the fluid pressure type cylinder mechanism B to change.
Alternatively, the rear room 14b is switched to be sent.

Therefore, as shown in FIG. 6, when the connecting rod 3 rises while inclining to the left when a high compression ratio is commanded, one arcuate groove 36 is set to a high pressure and the other arcuate groove 37 is set to a low pressure. It operates like
At this time, since the switching element 17 of the fluid pressure switching mechanism C is located at the right side position, the hydraulic pressure is sent from the oil passage 13 'through the oil passage 12 in the direction of pushing out the conrod pin 11.

When the connecting rod 3 descends while inclining to the right, the other arcuate groove 37 is operated to have a high pressure and the other arcuate groove 36 is to have a low pressure. At this time, the oil passage 13 is operated. The hydraulic pressure is sent in the direction from which the connecting rod pin 11 is pulled out through the oil passage 12 '. Further, when the connecting rod 3 rises while inclining to the left at the time of a low compression ratio command, one of the arcuate grooves 36 is set to a high pressure and the other arcuate groove 37 is set to a low pressure, as in the previous case. However, at this time, since the switching element 17 of the fluid pressure switching mechanism C is located at the left side position, the hydraulic pressure is sent from the oil passage 13 'through the oil passage 12' to the connecting rod pin 11.

When the connecting rod 3 descends while inclining to the right, the other arcuate groove 37 is operated to have a high pressure and one arcuate groove 36 is to have a low pressure. At this time, the oil passage 13 is operated. The hydraulic pressure is sent in a direction in which the connecting rod pin 11 is pushed out via the oil passage 12 from. Further, the oil passage 24 for sending the hydraulic pressure for the high compression ratio command or the low compression ratio command to the fluid pressure switching mechanism C has another oil passage 40 which is not axially displaced from the arcuate grooves 36 and 37. At the oil passage 2 of the crankshaft 25
It communicates with the switching valve 31 of the hydraulic pressure supply circuit shown in FIG.

The hydraulic pressure supply circuit shown in FIG. 7 includes a reservoir 28, an oil pump 29 and an oil filter 3.
An oil supply passage 32 communicating with the switching valve 31 via 0 and an oil return passage 32 'communicating with the switching valve 31 without passing through the oil pump 29 are formed. Passage 2
Via 6 is communicated with the oil passage 24 of the connecting rod 3.

Further, the switching valve 31 of the hydraulic pressure supply circuit is connected to a controller 35 which receives detection signals from the engine load sensor 33, the engine speed sensor 34 and the like and sends a switching signal to the switching valve 31. In the figure, reference numerals 41 and 42 denote oil passages to the fluid pressure generating portion D. That is, as shown in FIG. 16, when it is necessary to obtain the detection signals of the engine load sensor 33 and the engine rotation speed sensor 34 for the operating condition of the engine and to operate the engine in the high compression ratio condition, An oil return path 32 'that issues a compression ratio command and causes the switching valve 31 not to pass through the oil pump 29.
The reservoir pressure (low pressure) is applied to the oil passage 24.

As a result, a low pressure is applied to the fluid pressure switching mechanism C, and the switching element 17 is pushed by the spring 16 and moves to the right. In addition, each sensor 33, 34
When it is necessary to operate the engine in a low compression ratio state by receiving the detection signal of, the controller 35 issues a low compression ratio command to connect the switching valve 31 to the oil supply path 32 via the oil pump 29. Therefore, a high pressure is applied to the oil passage 24.

As a result, a high pressure is applied to the fluid pressure switching mechanism C, and the switching element 17 pushes the spring 16 and moves to the left (the position in FIG. 2). Next, the operating state of this device will be described with reference to FIGS. First, FIGS. 8 to 11 show that the device receives a high compression ratio command (hereinafter, referred to as “high command” as necessary) from a low compression ratio condition (hereinafter, referred to as “low condition” if necessary). , A high compression ratio state (hereinafter referred to as a "high state" as necessary).

That is, when a high command is issued from the controller 35 in the low state shown in FIG. 8, the hydraulic pressure in the oil passage 24 becomes the reservoir pressure (low pressure state), so that the switching element 17 of the fluid pressure switching mechanism C is a spring. The urging force of 16 moves to the right in FIG. 4, and the high hydraulic pressure from the fluid pressure generating section D becomes 36-
It is sent to the rear chamber 14b of the fluid pressure type cylinder mechanism B by the path 13'-h-b-12.

In this state, the connecting rod 3 is the first
When the lock pin 6, the through hole 9, and the connecting rod pin 11 are aligned in a straight line at the inclined position (position in FIG. 8), high pressure is being sent to the rear chamber 14b of the fluid pressure cylinder mechanism B. The connecting rod pin 11 is pushed out a little and the lock pin 6 is retracted to release the engagement state between the piston 1 and the eccentric sleeve 5, and the connecting rod 3 and the eccentric sleeve 5 are fixed to obtain the state of FIG.

Therefore, in the state of FIG. 9, since the eccentric sleeve 5 is adapted to rotate together with the connecting rod 3, the connecting rod 3 rotates as indicated by the arrow i in FIG. 8 and is indicated by the dotted line in FIG. After going through the transient state,
At the second tilted position (position in FIG. 10), the high pressure from the fluid pressure generator D is now high in the front chamber 14a of the fluid pressure cylinder mechanism B through the route of 37-13-fd-12 '. , The connecting rod pin 11 is pulled out from the through hole 9 and retracts, and the lock pin 7 is pushed out by the biasing force of the spring 8 and enters the through hole 9, resulting in the state shown in FIG.

As a result, the connecting rod 3 and the eccentric sleeve 5 are freely rotatable, the eccentric sleeve 5 and the piston 1 are locked, and the high state is fixed as shown in FIGS. Then, connecting rod 3
As shown by an arrow j in FIG. 10, the eccentric sleeve 5 is kept fixed at the position of the lock pin 7 on the right side of the piston 1 even if the pendulum is moved. By fixing, the operation in the high compression ratio state is continuously performed.

Next, FIGS. 12 to 15 show a process in which the present apparatus receives a low compression ratio command (hereinafter referred to as a “low command” as necessary) from the high state and shifts to the low state. is there. That is, in the high state shown in FIG. 12, when a low command is issued from the controller 35, the hydraulic pressure of the oil passage 24 becomes a high pressure state, so that the switching element 1 of the fluid pressure switching mechanism C is changed.
7 presses the spring 16 to be in the state of FIG. 4, and the high pressure from the fluid pressure generating portion D is sent to the rear chamber 14b of the fluid pressure type cylinder mechanism B by the route of 37-13-e-a-12. Has become.

In this state, the connecting rod 3 is moved to the second position.
When the lock pin 6, the through hole 9, and the connecting rod pin 11 come to a straight line at the inclined position (position of FIG. 12),
Since the high pressure is sent to the rear chamber 14b of the fluid pressure type cylinder mechanism B, the connecting rod pin 11 is pushed out to retract the lock pin 6 to release the locked state between the piston 1 and the eccentric sleeve 5, and the connecting rod. 3 and the eccentric sleeve 5 are fixed to obtain the state of FIG.

Therefore, in the state of FIG. 13, since the eccentric sleeve 5 is adapted to rotate together with the connecting rod 3, the connecting rod 3 turns as indicated by an arrow k in FIG. 12, and the transient shown by a dotted line in FIG. After passing through the state, when it reaches the first inclined position (position in FIG. 14), the high pressure from the fluid pressure generating portion D is 36-13'-f-d-1 this time.
The front chamber 14a of the fluid pressure type cylinder mechanism B by the route 2 '.
Since high pressure is sent to the connecting rod pin 11,
Then, the lock pin 7 is pulled out from the housing and retracted, and the lock pin 7 is projected by the biasing force of the spring 8 and enters the through hole 9, resulting in the state of FIG.

As a result, the connecting rod 3 and the eccentric sleeve 5 are free to rotate, the eccentric sleeve 5 and the piston 1 are locked, and the low state is fixed as shown in FIGS. Then, connecting rod 3
, As shown by the arrow m in FIG. 14, the eccentric sleeve 5 is maintained in a fixed state at the position of the lock pin 6 on the left side of the piston 1, even if the pendulum is moved. By fixing, the operation in the low compression ratio state is continuously performed.

Further, FIG. 17 shows another example of the fluid pressure generator D, which is constructed in the connecting rod 3 in a closed circuit pulled out from the fluid pressure switching mechanism C. There is something. That is, in this closed circuit, a slightly elongated fluid pressure generating space 22 is formed along the axial direction of the connecting rod 3, and a mass fitted in a floating state in the fluid pressure generating space 22. A body (mass) 23 is provided, and the insides of the fluid pressure generating space 22 on both end sides of the mass body 23 are respectively fluid pressure chambers 22a, 2a.
Formed as 2b.

The fluid pressure chamber 22a communicates with the fluid pressure switching mechanism C via the oil passage 13 ', and the fluid pressure chamber 22b communicates with the fluid pressure switching mechanism C via the oil passage 13, thereby forming a closed circuit. Are formed. Accordingly, when the connecting rod 3 moves upward while inclining to the right (compression stroke and exhaust stroke of the combustion chamber), the mass body 23 moves downward due to inertial force, and the fluid pressure on the front side of the mass body 23 moves. Chamber 22a
To generate a high hydraulic pressure in the fluid pressure chamber 22b on the rear side of the moving mass body 23. This high hydraulic pressure is sent to the fluid pressure switching mechanism C through the oil passage 13 '. Has become.

When the connecting rod 3 tilts leftward and moves downward (intake stroke and expansion stroke of the combustion chamber)
The mass body 23 moves upward due to the inertial force, and contrary to the above, a high hydraulic pressure is generated in the fluid pressure chamber 22b.
A low hydraulic pressure is generated in a, and the high hydraulic pressure is sent to the fluid pressure switching mechanism C through another oil passage 13.

As described above, in the variable compression ratio device for an engine according to the present invention, the variable amount of the compression ratio is determined by the change of the tilt angle due to the movement of the connecting rod 3, and the small end is accompanied by the pendulum movement of the connecting rod 3. Since the eccentricity amount of the eccentric sleeve 5 is determined by forcibly rotating the eccentric sleeve 5 of the portion, the compression ratio can be switched regardless of the inertia force or the combustion pressure as in the conventional case. It is certainly done.

Further, by simultaneously switching the fluid pressure switching mechanism C at the same time as the high compression ratio command or the low compression ratio command, the pushing and pulling out operation of the connecting rod pin 11 is automatically switched, and a high pressure is applied to this operation. Therefore, the operation of the connecting rod pin 11 is surely performed. In addition, high pressure and low oil pressure are alternately supplied by the rotation of the crank pin 4 accompanying the movement of the connecting rod large end 3b to generate high pressure for pushing and pulling out the connecting rod pin. Since it is applied alternately in the pushing direction and the pulling direction of the rod rod 11, it is effective for the connecting rod pin 11 to perform a reliable operation.

Moreover, in this case, the oil passage 3 on the high pressure side
If a high hydraulic pressure is supplied to 8 or 39, the connecting rod pin 11 can be operated with a much higher hydraulic pressure by this high hydraulic pressure and the hydraulic pressure due to the rotational centrifugal force of the crank pin 4. In addition, connecting rod pin 11
Since the high pressure for the pushing and pulling operations of the connecting rod 3 is generated by utilizing the inertial force of the mass body 23 provided in the connecting rod 3, in this case, the connecting rod pin 11 has a simple structure. This is effective for ensuring reliable operation.

Further, since the connecting rod pin 11 and the lock pins 6 and 7 are configured to push the lock pins 6 and 7 and the connecting rod pin 11 via the sleeve pin 10 which is slightly shorter than the through hole 9, the respective pins are pushed. 6,
7 and 11 can well transmit the movement to the mating pin with a small stroke and can surely perform the engaging / disengaging operation between the pins.

[0068]

As described in detail above, according to the variable compression ratio device for an engine of the present invention according to claim 1, an eccentric sleeve is rotatably interposed between the small end portion of the connecting rod and the piston pin. In the variable compression ratio device of the engine capable of varying the compression ratio in the combustion chamber by fixing the eccentric sleeve and the piston pin at a predetermined position, on the piston pin bearing portion lower inner wall of the piston,
Two lock pins, which have a predetermined opening to the left and right with respect to the center vertical line of the piston pin and are on the same circumference with respect to the axis of the piston pin, are urged inward of the piston. Is provided horizontally, and the eccentric sleeve that is fitted into the piston pin and rotated by the pendulum motion of the connecting rod is provided, and the flange portion that hangs from a part of the eccentric sleeve faces the two lock pins individually. A horizontal through-hole is formed, and further, a small end portion of the connecting rod is laterally connected to one of the lock pins by sandwiching the collar portion when the connecting rod is in the first inclined position. A connecting rod pin is provided which is opposed to and is opposite to the other lock pin across the collar when the connecting rod is in a second inclined position sandwiching the first inclined position and the central vertical line. When the high compression command is issued, the connecting rod pin is pushed out into the through hole aligned when the connecting rod is in the first tilted position, and the connecting rod is pushed when the connecting rod is in the second tilted position. When the pin is pulled out and the low compression command is issued, the connecting rod pin is pushed out into the through hole that aligns when the connecting rod is in the second inclined position, and when the connecting rod is in the first inclined position, Since the connecting rod pin drive mechanism that drives the connecting rod pin is installed so as to pull out the connecting rod pin, the variable amount of the compression ratio is determined by the change of the inclination angle of the connecting rod, and the pendulum motion of the connecting rod is also determined. The eccentric amount of the eccentric sleeve is determined by the forced rotation of the Switching of the compression ratio has the advantage that is reliably performed without due urchin inertia Toka combustion pressure.

Further, according to the variable compression ratio device for an engine of the present invention according to claim 2, the connecting rod pin driving mechanism is embedded in the connecting rod, and a piston portion attached to the connecting rod pin is provided. A fluid pressure type cylinder mechanism having two fluid chambers partitioned by the piston portion, and a fluid pressure state for both fluid chambers of the fluid pressure type cylinder mechanism, which is also embedded in the connecting rod and is in a high pressure state or a low pressure state. Since a fluid pressure switching mechanism for switching to and a fluid pressure generating unit for generating high-pressure fluid and low-pressure fluid are provided in the circuit drawn out from the fluid pressure switching mechanism, the compression ratio switching operation is performed. Is automatically and reliably performed by each mechanism constituting the connecting rod pin drive mechanism.

Further, according to the variable compression ratio device for an engine of the present invention according to claim 3, the fluid pressure generating portion is provided at the large end portion of the connecting rod, and the fluid pressure generating portion accompanies the swinging motion of the connecting rod. By the rotation of the crank pin,
Since it is configured as a fluid pressure generating unit that alternately supplies high hydraulic pressure and low hydraulic pressure to one side and the other side between the connecting rod and the crank pin, the connecting rod pin is reliably moved at high pressure. There are possible advantages.

Further, according to the variable compression ratio device for an engine of the present invention according to claim 4, the fluid pressure generating portion is provided between the large end portion of the connecting rod and the crank pin, and each of the fluid pressure generating portion is provided with the fluid pressure generating portion. A pair of left and right arcuate grooves that communicate with the switching mechanism, and a pair of oil passages that are provided from the inside of the crank pin toward the outside and that face each other and can communicate with the pair of arcuate grooves. By the rotation of the crank pin, a high fluid pressure from the oil passage on one side and a low fluid pressure from the oil passage on the other side are alternately generated in the arcuate groove on one side and the passage on the other side. Therefore, there is an advantage that the high pressure applied to the connecting rod pin can be automatically and alternately supplied to surely perform the operation of the connecting rod pin.

Further, according to the variable compression ratio device for an engine of the present invention according to claim 5, the fluid pressure generating portion is provided inside the connecting rod and is arranged along the axial direction of the connecting rod. A fluid pressure generating space,
Both ends of the mass body in the space portion by fitting the mass body in the space portion in a floating state, and by inserting the mass body in the space portion in the floating state. A pair of fluid pressure chambers facing each other are formed, and by the vertical movement of the connecting rod, a high pressure is generated in the fluid pressure chamber on the moving destination side of the mass body, and the fluid pressure chamber on the opposite side of the moving destination of the mass body is formed. Since the low pressure is generated in the fluid pressure chamber, there is an advantage that the high pressure applied to the connecting rod pin can be automatically and alternately supplied by a simple structure.

According to the sixth aspect of the present invention, in the variable compression ratio device for an engine of the present invention, the eccentric sleeve collar portion is provided with a sleeve pin slightly shorter than the length of the through hole in the through hole. Since the lock pin and the connecting rod pin are opposed to each other via the sleeve pin, both the ronk pin and the connecting rod pin have an advantage that the movement can be transmitted to the mating pin with a small amount of movement.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a connecting rod portion showing an embodiment of a variable compression ratio device for an engine according to the present invention.

FIG. 2 is a side view taken along line II-II of FIG.

FIG. 3 is an overall configuration diagram of the present apparatus.

FIG. 4 is an enlarged cross-sectional view of a fluid pressure switching mechanism of this device.

FIG. 5 is a cross-sectional view of a fluid pressure generator of the present device.

FIG. 6 is an operation explanatory view of the fluid pressure generating unit according to FIG.

FIG. 7 is a hydraulic pressure supply circuit diagram of the present device.

FIG. 8 is a small end side view showing an operating state when a high compression ratio command is issued in a low compression ratio state.

9 is a cross-sectional view taken along the line IX-IX of FIG.

FIG. 10 is a small end side view showing a high compression ratio state.

11 is a cross-sectional view taken along the line XI-XI of FIG.

FIG. 12 is a small end side view showing an operating state when a low compression ratio command is issued in a high compression ratio state.

13 is a sectional view taken along the line XIII-XIII in FIG.

FIG. 14 is a small end side view showing a low compression ratio state.

15 is a sectional view taken along the line XV-XV in FIG.

FIG. 16 is a high / low compression ratio region diagram showing a high compression ratio region and a low compression ratio region of the engine.

FIG. 17 is a cross-sectional view of a connecting rod portion showing another example of the fluid pressure generating portion.

FIG. 18 is an overall configuration diagram in which an eccentric sleeve is provided at a large end of a connecting rod according to a conventional example.

[Explanation of symbols]

 1 Piston 1a Bearing part 2 Piston pin 3 Connecting rod 3a Small end part 3b Large end part 4 Crank pin 5 Eccentric sleeve 5a Collar part 6,7 Lock pin 8 Spring 9 Through hole 10 Sleeve pin 11 Connecting rod pin (connecting rod pin) 11a Piston part 12, 12 ', 13, 13' Oil passage 14 Fluid chamber 14a Front chamber 14b Rear chamber 15 Switching chamber 16 Spring 17 Switcher 18, 20 Upright passage 19, 21 Inclined passage 22 Fluid pressure generating space 22a, 22b Fluid pressure chamber 23 Mass body 24 Oil passage 25 Crankshaft 26, 27, 38, 39, 40, 41, 42 Oil passage 28 Reservoir 29 Oil pump 30 Oil filter 31 Switching valve 32 Oil supply passage 32 'Oil return passage 33 Engine load Sensor 34 Engine speed sensor 3 5 controller 36, 37 arcuate groove a, b, c, d, e, f, g, h lateral groove v vertical center line A connecting rod pin drive mechanism B fluid pressure type cylinder mechanism C fluid pressure switching mechanism D fluid pressure generation unit

Claims (6)

[Claims] 1. A eccentric sleeve is rotatably interposed between a small end of a connecting rod and a piston pin, and the compression ratio in the combustion chamber is varied by fixing the eccentric sleeve and the piston pin at a predetermined position. In the variable compression ratio device for an engine, the piston pin bearing portion lower inner wall of the piston has a predetermined opening to the left and right with respect to the center vertical line of the piston pin, and the piston pin has an axial center. On the other hand, two lock pins on the same circumference are provided horizontally by being biased inwardly of the piston, and the eccentricity is inserted into the piston pin and rotated by the pendulum motion of the connecting rod. A sleeve is provided, and a horizontal penetrating hole that can individually face the two lock pins is provided in a flange portion that is hung from a part of the sleeve. On the side of the small end portion of the lid, when the connecting rod is in the first inclined position, the connecting rod faces one of the lock pins with the collar portion interposed therebetween, and the connecting rod has the first inclined position. And a connecting rod pin that faces the other lock pin across the collar when it is in the second inclined position with the central vertical line in between, and when the high compression command is issued, the connecting rod is the first The connecting rod pin is pushed out into the through hole aligned when the connecting rod is in the inclined position, and the connecting rod pin is pulled out when the connecting rod is in the second inclined position. The connecting rod pin is pushed into the through hole that aligns when in the second tilted position and the connector rod is in the first tilted position when the connecting rod is in the first tilted position. A variable compression ratio device for an engine, comprising a connecting rod pin drive mechanism for driving the connecting rod pin so as to pull out the connecting rod pin. 2. The connecting rod pin drive mechanism comprises:
Embedded in the connecting rod, a fluid pressure cylinder mechanism having a piston part attached to the connecting rod pin and two fluid chambers partitioned by the piston part, and also embedded in the connecting rod, A high-pressure fluid and a low-pressure fluid are generated in a fluid pressure switching mechanism that switches a fluid pressure state to both fluid chambers of the fluid pressure type cylinder mechanism to a high pressure state or a low pressure state, and a circuit drawn from the fluid pressure switching mechanism. 2. The variable compression ratio device for an engine according to claim 1, wherein the variable compression ratio device is configured to include a fluid pressure generating unit that operates. 3. The fluid pressure generating portion is provided at a large end portion of the connecting rod, and the fluid pressure generating portion is rotated between the connecting rod and the crank pin by the rotation of the crank pin due to the swinging motion of the connecting rod. On one side and the other,
The variable compression ratio device for an engine according to claim 2, wherein the variable pressure ratio device is configured as a fluid pressure generation unit that alternately supplies high hydraulic pressure and low hydraulic pressure. 4. The fluid pressure generating portion is provided between the large end portion of the connecting rod and a crank pin, and a pair of left and right arcuate grooves that communicate with the fluid pressure switching mechanism, respectively.
The crank pin is provided outward from the inside, and is configured with a pair of oil passages that face each other and can communicate with the pair of arcuate grooves, and by the rotation of the crank pin,
A high fluid pressure from the oil passage on one side and a low fluid pressure from the oil passage on the other side are alternately generated in the arcuate groove on the one side and the passage on the other side. And
The variable compression ratio device for an engine according to claim 3. 5. The fluid pressure generating portion is provided inside the connecting rod, and the fluid pressure generating space portion is disposed along the axial direction of the connecting rod, and is fitted in the space portion in a floating state. A pair of fluid pressure chambers facing each other at both ends of the mass body in the space portion by inserting the mass body in a floating state. Is formed, and by the vertical movement of the connecting rod, a high pressure is generated in the fluid pressure chamber on the moving side of the mass body, and a low pressure is generated in the fluid pressure chamber on the opposite side to the moving destination of the mass body. The variable compression ratio device for an engine according to claim 2, wherein the variable compression ratio device is configured as described above. 6. A sleeve pin slightly shorter than the length of the through hole is provided in the through hole of the eccentric sleeve collar portion,
2. The variable compression ratio device for an engine according to claim 1, wherein the lock pin and the connecting rod pin are opposed to each other via the sleeve pin.