JPH0566240U - Variable compression ratio device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Object] An object of the present invention is to obtain a variable compression ratio device having a structure capable of smoothly switching the eccentric position of an eccentric sleeve, in other words, switching the compression ratio. is there. According to the present invention, flanges 3A and 3B of an eccentric sleeve 3 which are configured to rotate in one direction only by centrifugal force are engaged with a shock absorber 8 of the eccentric sleeve 3. The cutout portion 3C is provided, and when the cutout portion 3C collides with the one side, a pin 12 having a structure for retracting from the cutout portion 3C on the other side is provided, and the position of the cutout portion 3C is set. The position where the rotation of the eccentric sleeve 3 in one direction due to centrifugal force is not obstructed is characterized by a structure that does not require switching of the rotation direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable compression ratio device for an internal combustion engine, and more particularly, to a rotation damping structure for an eccentric sleeve used to change the compression ratio.

[0002]

[Prior Art]

 Generally, in an automobile engine, which is one of the internal combustion engines, it is necessary to prevent knocking when operating in a high load range above the medium load range or in the high speed rotation range of the engine, and to reduce the load range below the medium load range A structure that can change the compression ratio has been proposed for the purpose of increasing the thermal efficiency and improving the consumption rate of the fuel during operation.

As a structure of this variable compression ratio device, there is one described in the specification of Japanese Patent Application No. 3-338859, which is a prior application by the present applicant. According to this, a rotatable eccentric sleeve is arranged between the outer peripheral surface of the crankpin of the crankshaft and the inner peripheral surface of the bearing hole at the large end of the connecting rod. It is possible to switch between the maximum eccentric position that raises the central position of the piston pin on the piston side and the minimum eccentric position that lowers the central position of the piston pin on the connecting rod side when rotating due to the centrifugal force of Is becoming That is, when the rotation direction of the crankshaft is set to the clockwise direction, the centrifugal force on the eccentric sleeve due to the rotation of the crankshaft and the force from the inertial force applied to the center of gravity of the eccentric sleeve itself. The sum of and causes the eccentric sleeve to rotate clockwise. This rotational force is also maintained by the viscosity of the oil present in the oil passage forming gap provided between the large diameter bearing surface of the connecting rod and the crank pin. It has become.

By the way, regarding the rotational state of the eccentric sleeve due to the centrifugal force with respect to the displacement of the piston, in the range from the bottom dead center to the top dead center of the piston, the centrifugal force effectively acts and the crank The rotation of the eccentric sleeve in the clockwise direction is maintained with the pin center as the fulcrum, while the combustion pressure acts on the center of the large end of the connecting rod in the range from the top dead center to the bottom dead center of the piston. As shown in FIG. 7, the center position A of the eccentric sleeve is biased by the component force to the left generated in that case, and the center position of the large end is offset to the left from the center of the crank pin accordingly. As described above, the moment M that causes the eccentric sleeve to rotate about the crankpin center as a fulcrum in the opposite direction to that in the past occurs. Therefore, in the range from the bottom dead center to the top dead center of the piston, the rotation of the eccentric sleeve using the weight mass of the large diameter part due to the centrifugal force switches from the minimum eccentric position to the maximum eccentric position. In the range from the top dead center to the bottom dead center of the piston, switching from the maximum eccentric position where the large diameter part returns to the original position to the minimum eccentric position is performed. However, it has a conventional structure.

As described above, since the eccentric sleeve changes its rotation direction in the forward and reverse directions during one rotation of the crankshaft, it is necessary to fix the position of the eccentric sleeve when rotating in each direction. , And the structure for this is adopted. In this structure, in the flanges located at both axial ends of the eccentric sleeve, locking recesses alternately formed along the circumferential direction to determine the maximum eccentric position and the minimum eccentric position, and the locking portions. It is composed of a lock pin that is capable of projecting and retracting in the recess by hydraulic control. By switching the projecting position of this lock pin, the eccentric sleeve is fixed at each eccentric position. .. Among the above-mentioned locking recesses, the locking recess formed on the flange for fixing the eccentric sleeve at the maximum eccentric position is generated from the combustion pressure against the viscosity of the oil for transmitting the centrifugal force described above. As shown in FIG. 8, in order to make the rotary moment effectively act on the large diameter part and thereby perform the rotation utilizing the weight mass in the large diameter part, in the range where the combustion pressure acts, The center of the large-diameter part of the eccentric sleeve is located so as to correspond to the tilted position of the connecting rod, and is biased to a position where counterclockwise rotation easily occurs from the center line of the connecting rod. A locking recess is formed to fix the eccentric sleeve at a minimum eccentric position at a predetermined angle from the recess.

Further, this flange is provided with a structure for matching the engagement relationship between the locking recess and the lock pin. This structure is provided in the circumferential direction of the flange of the eccentric sleeve described above. A notch that forms a step for abutment is provided between the locking recesses of the pin, and a pin provided in a shock absorber that damps the rotation of the eccentric sleeve caused by an elastic body or oil against the notch. Both ends in the axial direction are configured to abut on the upstream side in the rotational direction with respect to the notch.

[0007]

[Problems to be solved by the device]

 However, in a variable compression ratio device equipped with an eccentric sleeve whose rotation direction changes during one rotation of the crankshaft, the viscosity of the oil present in the oil passage forming gap located on the outer periphery of the eccentric sleeve However, if the combustion pressure acts on the connecting rod, the switching of the eccentric sleeve in the rotating direction may become unstable.

Further, since the combustion pressure is considerably large, the pressure in the oil passage forming gap impairs uniformity due to the pressure, and the location where the eccentric sleeve outer peripheral surface faces the gap across the gap. In some cases, frictional resistance occurs between the two, impairing the rotation of the eccentric sleeve, and smooth switching of the eccentric position becomes impossible.

Moreover, the locking recess formed in the eccentric sleeve is offset from the center line so that it is easy to rotate in the counterclockwise direction for switching from the maximum eccentric position to the minimum eccentric position. Since this is done, the action of the centrifugal force generated by the rotation of the crankshaft is impaired, resulting in power loss.

Therefore, in view of the problem in the conventional variable compression ratio device, an object of the present invention is to provide a structure capable of smoothly switching the eccentric position of the eccentric sleeve, in other words, switching the compression ratio. To obtain a variable compression ratio device.

[0011]

[Means for Solving the Problems]

 In order to achieve this object, the present invention provides a rotatable eccentric sleeve which is arranged between the bearing surface at the large end of the connecting rod and the crankshaft outer peripheral surface of the crankshaft inserted into the bearing surface. Using this eccentric sleeve, the pivoting position of the connecting rod and the piston is raised with respect to the bearing rod center position of the connecting rod, and the above-mentioned pivoting position is lowered. In a variable compression ratio device for an internal combustion engine, which is provided with a mechanism for switching to a position where a low compression ratio state is obtained, the variable compression ratio device is formed along the circumferential direction of flanges located at both axial ends of the eccentric sleeve. The maximum and minimum eccentric positioning locking recesses are provided in parallel with the axial direction of the eccentric sleeve so as to project into and retract from the notches provided in one of the flanges. Direction When projecting is characterized in that a shock absorber having a pin which is set the axial length, which can be retracted from the other flange.

Further, according to the present invention, the cutout portion of the eccentric sleeve is such that the center of the large end portion of the connecting rod and the center of the crank pin are in the range from the top dead center to the bottom dead center of the piston. It is characterized in that the center of the part and the center of the crank pin are arranged in the combustion pressure acting direction so that the engagement between the switching mechanism and the locking recess on the flange side can be set.

Further, according to the present invention, the shock absorber has a hydraulic chamber partitioned by a flange of a pin inserted inside, and between the one side of the flange and the one side of the hydraulic chamber. Usually, there is a return spring that has the habit of moving the pin toward the notch on one flange, and in the other hydraulic chamber, the pin is moved from the normal position to the notch on the other flange. It is characterized by being connected to an oil passage for supplying / discharging the working oil for moving toward the direction.

Further, according to the present invention, an oil passage connected to the other hydraulic chamber of the shock absorber is connected to a control valve, and the control valve is provided in accordance with switching of the eccentric position of the eccentric sleeve. It is characterized by setting the supply / drainage position of the working oil to the other hydraulic chamber.

[0015]

[Action]

 According to the present invention, the eccentric sleeve is formed on the flange on one side of the eccentric sleeve when the pin in the shock absorber projects toward the one flange of the eccentric sleeve when it is rotated by centrifugal force. The eccentric sleeve is unidirectional because it abuts the notch, and when it projects toward the other flange of the eccentric sleeve, it abuts the notch formed on the other flange. It is possible to prevent the rotation from being obstructed when rotating. .

Further, according to the present invention, when the combustion pressure acts on the connecting rod, the rotation of the eccentric sleeve is a fixed position by the notch, and the center of the large end and the center of the crankpin act as a pressure field. By arranging them in the same direction, the influence of offset that causes momentum in the counterclockwise direction is suppressed and rotation in one direction using centrifugal force is continued during one rotation of the crankshaft. be able to.

Further, according to the present invention, since the eccentric sleeve rotates in one direction, the cutouts formed in the flange of the eccentric sleeve can be oriented in the same direction.

[0018]

【Example】

 Hereinafter, details of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a front view showing the appearance of a connecting rod in a variable compression ratio device according to an embodiment of the present invention. In this figure, the bearing surface at the large end of the connecting rod 1 and the outer circumference of the crankpin 2A at the crankshaft 2 are shown. A rotatable core eccentric sleeve 3 is arranged between the surface and the surface. The eccentric sleeve 3 has an outer peripheral surface that is eccentric with respect to the center of the crank pin 2A, and the flanges 3A and 3B (see FIG. 2) formed at both ends in the axial direction thereof are, for example, 180. Locking recesses 3A1 and 3B1 formed by notches are alternately provided at positions where the maximum eccentric position and the minimum eccentric position can be determined by the phase of the degree.

As shown in FIG. 3, the positions of the locking recesses 3A1 and 3B1 are such that the center of the large end portion of the connecting rod 1 and the center of the crank pin have combustion pressures in the range from the top dead center to the bottom dead center of the piston. The position is such that the eccentric sleeve 3 can be fixed in such a way that it is aligned in the direction of action. Therefore, when the combustion pressure acts on the connecting rod 1, there is no offset between the center of the crankpin and the center of the connecting rod because the center of the large end rotates counterclockwise. The influence of the moment that switches the rotation in the counterclockwise direction is suppressed, and the eccentric sleeve 3 has a centrifugal force only, and the rotation direction in the range from the bottom dead center to the top dead center of the piston is Similarly, it is possible to maintain the clockwise rotation.

A lock mechanism 4 is arranged so as to face the locking recesses 3A1 and 3B1. The lock mechanism 4 is for fixing the eccentric sleeve 3 at the maximum and minimum eccentric positions when the eccentric sleeve 3 rotates. A stopper pin 5 that is slidable in the axial direction is provided. As shown in FIG. 4, the stopper pin 5 is inserted into the hydraulic chamber 1A formed at the large end portion of the connecting rod 1 and has a large diameter portion formed at a substantially middle portion in the sliding direction. Due to the habit of the return spring 4A arranged in one of the partitioned hydraulic chambers, one of the locking recesses formed in one of the flanges of the eccentric sleeve 3, that is, in FIG. As shown in (A), it projects toward the locking recess 3A1 formed in the small diameter portion corresponding to the minimum eccentric position. In FIG. 4, reference numeral 4B indicates a receiving seat for the return spring 4A. The hydraulic chamber 1A constitutes a drive actuator for sliding the stopper pin 5, and the drive actuator is partitioned by the large diameter portion of the stopper pin 5. The oil passages 6 and 7 connected to the hydraulic chamber are provided, and the sliding position of the stopper pin 5 is switched by controlling the supply and discharge of oil to the oil passages 6 and 7 so that the eccentric position of the eccentric sleeve 3 is determined. Is becoming

On the other hand, the flanges 3A and 3B of the eccentric sleeve 3 are provided with notches 3C having stepped portions between the respective locking recesses when the eccentric sleeve 3 is viewed from the front. The notch 3C is provided alternately with the flanges 3A and 3B at a position facing the shock absorber 8 to be described later on the upstream side in the rotation direction of the eccentric sleeve 3 (in FIG. The cutout portion 3C formed in the flange at the opposite position is shown by a chain double-dashed line). The shock absorber 8 is for stopping the rotation of the eccentric sleeve 3 toward a position where the locking recess on the flange side can be engaged with the stopper pin 5 of the lock mechanism 4, and the connecting rod 1 Has a casing formed at the lower end of the casing, and a hydraulic chamber is formed inside the casing. Further, in the hydraulic chamber, a tangential direction in the circumferential direction of the eccentric sleeve 3 is formed. And a slidable piston member 9 is arranged. A return spring 10 is arranged between the piston member 9 and the hydraulic chamber, and an oil passage 11 is connected to a space on the side where the return spring 10 is arranged. The oil passage 11 communicates with an oil passage forming gap between the bearing surface of the connecting rod 1 and the outer peripheral surface of the eccentric sleeve 3. Further, the return spring 10 normally biases the piston member 9 toward the upstream side in the rotational direction of the eccentric sleeve 3, and the movement caused by this bias is formed in a casing. It is designed to be regulated by locking a pin, which will be described later, on the edge of the guide hole. Further, the oil from the oil passage 11 connected to the hydraulic chamber causes displacement of the piston member when the notch 3C formed in the flange of the eccentric sleeve 3 and a pin to be described later collide with each other. It functions as a damper that is attenuated by the throttling effect of the oil passage 11. The elastic deformation force of the return spring 10 is also exerted as the damper function.

On the other hand, as shown in FIG. 5, the piston member 9 has a hydraulic chamber 9A formed in a direction perpendicular to the direction in which it is pushed and moved by the cutout portion 3C of the eccentric sleeve 3. A pin 12 slidable in the hydraulic chamber is inserted into the hydraulic chamber 9A. The pin 12 is set to have an axial length capable of colliding only with one notch 3C of the flanges 3A and 3B, and when protruding toward one notch 3C, the other of the notches 3C is provided. The hydraulic chamber 9A is separated from the cutout portion 3C by a collar formed at the middle portion in the lengthwise direction. A return spring 13 is provided in one of the hydraulic chambers 9A partitioned by the collar, and one end of a control oil passage 14 connected to an oil passage communicating with the lock mechanism 4 in the other hydraulic chamber. Are connected. In the case of the present embodiment, the pin 12 is a flange in which a locking recess 3A1 for setting a minimum eccentric position is formed by the biasing of the return spring 10 as shown in FIG. 5 (A). When the oil is supplied to the control oil passage 14 in this position, as shown in FIGS. 5 (B) and 5 (C), The position is changed so as to abut against the notch 3C of the flange 3B in which the locking recess 3B1 for setting the maximum eccentric position is formed against the bias of the return spring 10. Is becoming

The oil supply / discharge control to / from the control oil passage 14 is performed by, for example, a hydraulic pressure control unit provided for the lock mechanism 4, and the structure will be described below. .. FIG. 6 is a circuit diagram showing the hydraulic control section of the lock mechanism 4, in which the oil passage 6 of the lock mechanism 4 is communicated with the main oil gallery 15, and the oil passage 7 and the control oil passage are connected. 14 communicates with the sub oil pump 16 or the main oil gallery 15. In this hydraulic control circuit, the pressure oil from the oil pan 17 is adjusted to a preset reference oil pressure by an oil pump 19 provided with a relief valve 18, and is fed to a main gallery 15 via a filter 20. The hydraulic oil of the reference pressure is supplied to each part in the engine including one of the hydraulic chambers of the drive actuator via the oil passage 6 which is supplied and communicates with the main gallery 15. There is. Further, a part of the pressure oil from the main gallery 15 is supplied to the sub oil pump 16 and is discharged as high pressure oil higher than the standard pressure, but the high pressure oil is selectively supplied by the switching valve 21. The oil is discharged toward the oil passage 7 and the control oil passage 14. That is, in FIG. 6, when the a port of the switching valve 20 is connected, the reference pressure oil from the main gallery 15 is supplied to the oil passage 6, and when the b port of the switching valve 20 is connected, the oil passage is connected. The high pressure oil from the auxiliary oil pump 16 is supplied to the control oil passage 7 and the control oil passage 14.

Therefore, when the b port of the switching valve 20 is connected, the high pressure oil from the sub oil pump 16 is supplied to the oil passage 7 and the control oil passage 14, and the return spring in the lock mechanism 4 is stopped. The high pressure oil is supplied to the hydraulic chamber side where 4A is not arranged and the high pressure oil is supplied to the hydraulic chamber side where the return spring 13 in the piston member 9 is not arranged. The stopper pin 5 in the mechanism 4 and the pin 12 in the piston member 9 move in the opposite direction against the urging force of the return springs 4A, 13. As a result, the stopper pin 5 slides toward the locking recess 3B1 formed in the flange 3B for fixing the eccentric sleeve 3 at the maximum eccentric position, as shown in FIG. 4 (B). After engagement of the pin 12 on the piston member 9 side and the cutout 3C of the flange 3B abutting against each other, the rotation of the connecting rod and the connecting rod relative to the center position of the bearing surface of the connecting rod and the piston are stopped. The distance from the center of the crank pin 3A, in other words, the distance from the center position of the crank pin 3A to the outer peripheral surface of the eccentric sleeve 4 is extended to set the high compression ratio state of the engine. become. Further, in the piston member 9, the pin 12 is set in a position capable of colliding with the cutout portion 3C of the flange 3B. Therefore, the eccentric sleeve 3 rotates in the time direction by centrifugal force until it comes into contact with the pin 12.

On the other hand, on the contrary, when the a port of the switching valve 21 is connected, the pressure oil of the reference pressure from the main oil gallery 15 is supplied to the oil passage 6, and the return spring 4A is arranged. Since the hydraulic oil of the reference pressure is also supplied through the oil passage 6 to the hydraulic chamber on the closed side, the stopper pin 5 slides by the biasing pressure of the return spring 4A. At this time, the hydraulic oil of the piston member 9 on the side where the return spring 13 is not arranged is also supplied with the reference pressure oil, but this pressure is set to a pressure that does not hinder the urging of the return spring 13. There is. Therefore, on the piston member 9 side, the pin 12 is in a position where it can abut with the notch 3C of the flange 3A in which the locking recess 3A1 for moving the eccentric sleeve 3 to the minimum eccentric position is formed. By the damping action in the case of abutment, the engagement recess 3A1 of the eccentric sleeve 3 and the stopper pin 5 can be engaged.

As a result, the stopper pin 6 is slidably engaged with the locking recess 4A1 corresponding to the minimum eccentric position in the state shown in FIG. 4 (A), and the eccentric sleeve 4 is engaged. Is fixed at the minimum eccentric position, and the low compression ratio state of the engine is set.

By the way, the switching operation of the switching valve 21 is set according to the load state and the number of revolutions of the engine, and the compression ratio of the engine is eliminated in order to eliminate the risk of knocking in the high rotation region and the high load region of the engine. Is set to a low compression ratio, and conversely, in other operating areas where knocking is less likely to occur, the compression ratio is increased to improve fuel efficiency as the heat coefficient increases. For this reason, the switching valve 21 is provided with a control solenoid valve 22 for setting the pilot pressure for setting the connection state of the switching valve 21, and the control solenoid valve 22 operates from the control unit 23. When the a port is connected by the signal, the pilot pressure of the switching valve 21 is lowered, and the a port of the switching valve 21 can be connected, and the b port on the control solenoid valve 22 side is connected. When the valve is connected, the pilot pressure of the switching valve 21 rises so that the b port of the switching valve 21 can be connected.

Since the present embodiment is configured as described above, the eccentric sleeve 3 is rotated clockwise by centrifugal force due to the rotation direction of the crankshaft 2, and this rotation is caused by the top dead center of the piston. Even in the range from the bottom dead center to the bottom dead center, it is continued due to the positional relationship between the notch portion 3C formed in the flange of the eccentric sleeve 3 and the locking recess, so that the crank shaft 2 rotates once. Rotate in the same direction. On the other hand, when the eccentric sleeve 3 rotates, the notch 3C formed on the flange thereof abuts the pin 12 provided on the piston member 9 of the shock absorber 8, but the lock mechanism 4 side When the position of the stopper pin 5 is set to engage with the locking recess 3A1 for setting the minimum eccentric position of the eccentric sleeve 3, the pin 12 of the piston member 9 is The normal position shown in FIG. 5 (A) is maintained. Therefore, the pin 12 can abut against the notch 3C of the flange 3A in which the engaging recess 3A1 for setting the minimum eccentric position of the flange of the eccentric sleeve 3 is formed. As a result, the rotation of the eccentric sleeve 3 is damped so that the engagement recess 3B1 and the stopper pin 5 can be engaged with each other.

When the position of the stopper pin 5 on the side of the lock mechanism 4 is set to the position of engaging with the locking recess 3B1 for setting the maximum eccentric position of the eccentric sleeve 3, As shown in FIGS. 5B and 5C, the pin 12 of the piston member 9 is hydraulically controlled via the control oil passage 14 so as to project in the opposite direction from the normal position. It is. Therefore, the pin 12 can abut against the notch 3C of the flange 3B in which the locking recess 3B1 for setting the maximum eccentric position of the eccentric sleeve 3 is formed. The rotation of the eccentric sleeve 3 is damped so that the stopper recess 5B and the stopper recess 5 can be engaged with each other.

[0030]

[Effect of the device]

 As described above, according to the present invention, when one of the notches of the flange provided at both axial ends of the eccentric sleeve projects toward the one notch, the other notch is formed. Since a shock absorber with a pin that can be retracted from is installed, each eccentric position can be reached without disturbing the rotation of the eccentric sleeve when fixing the eccentric sleeve to the maximum and minimum eccentric positions. Since it is possible to maintain the rotation up to, it is possible to smoothly switch the eccentric position.

Further, according to the present invention, when the combustion pressure acts on the connecting rod, the positional relationship of the notch portion provided on the flange of the eccentric sleeve is increased in the direction of the action of the combustion pressure. The eccentric sleeve is rotated in the direction opposite to the direction of rotation due to centrifugal force because the position where the switching mechanism and the locking recess are engaged is set so that the center of the end and the center of the crankpin are aligned. It is possible to prevent the unstable behavior when the rotation direction is switched by eliminating the influence of the offset on the side that causes the momentum and continuing the rotation in one direction by centrifugal force. Since the occurrence of resistance can be prevented in advance, the rotation can be smoothly performed and the compression ratio can be smoothly changed.

Further, according to the present invention, the eccentric sleeve is rotated along the rotation of the crankshaft, so that the eccentric sleeve can be fixed at each eccentric position by simple locking control. Since the flanges can have the same shape as each other, the structure can be simplified.

[Brief description of drawings]

FIG. 1 is a partial front view showing the appearance of a connecting rod which is a main part of a variable compression ratio device according to an embodiment of the present invention.

FIG. 2 is a side view of the connecting rod shown in FIG. 1 with a partial cross section.

FIG. 3 is a schematic diagram for explaining the inter-position diameter between the locking recess and the notch in the eccentric sleeve provided in the connecting rod shown in FIG.

FIG. 4 is a sectional view for explaining a lock mechanism used in the main part shown in FIG.

5 is a cross-sectional view for explaining the structure of the piston member of the shock absorber used in the main part shown in FIG.

6 is a hydraulic circuit diagram for explaining a configuration of a hydraulic control unit of the piston member shown in FIG.

FIG. 7 is a schematic view for explaining a problem in an eccentric sleeve having a conventional structure.

FIG. 8 is a schematic view for explaining the inter-position diameter of the locking recess in the eccentric sleeve having the conventional structure.

[Explanation of symbols]

 1 Connecting Rod 2 Crank Shaft 2A Crank Pin 3 Eccentric Sleeve 3A, 3B Flange 3A1, 3B1 Locking Recess 3C Notch 4 Lock Mechanism 5 Stopper Pin 8 Shock Absorber 9 Piston Member 12 Pin 14 Control Oil Path

Claims (4)

[Scope of utility model registration request] 1. An eccentric sleeve, which is disposed between a bearing surface at a large end portion of a connecting rod and a crankshaft outer peripheral surface on the side of a crankshaft to be fitted into the bearing surface and has a rotatable eccentric sleeve. -The position of the high compression ratio state where the pivotal position of the connecting rod and piston is raised with respect to the bearing surface center position of the connecting rod and the low compression ratio state where the pivotal position is lowered are In a variable compression ratio device for an internal combustion engine having a mechanism for switching to the obtained position, for maximum and minimum eccentric positioning for the eccentric sleeve, which are formed along the circumferential direction of flanges located at both axial ends of the eccentric sleeve. A notch provided between the locking recesses is provided so as to be capable of projecting and retracting in parallel with the axial direction of the eccentric sleeve. A variable compression ratio device for an internal combustion engine, comprising a shock absorber provided with a pin having an axial length that can be retracted from the engine. 2. The variable compression ratio device according to claim 1, wherein
The notch of the eccentric sleeve is burned between the center of the connecting rod and the center of the crank pin in the range from the top dead center to the bottom dead center of the piston between the center of the connecting rod and the center of the crank pin. A compression ratio device for an internal combustion engine, which is provided at a position where the engagement between the switching mechanism and the locking recess on the flange side can be set by having a relationship aligned in the pressure acting direction. 3. The variable compression ratio device according to claim 1,
The shock absorber has a hydraulic chamber that is partitioned by a flange of a pin that is inserted inside, and a pin is usually provided between one side of this flange and one side of the hydraulic chamber. A return spring that has the habit of moving the pin toward the notch on the other side is arranged, and hydraulic oil for moving the pin from the normal position to the notch on the other flange is supplied to the other hydraulic chamber. A variable compression ratio device for an internal combustion engine to which an oil passage for discharging is connected. 4. The variable compression ratio device according to claim 3,
An oil passage connected to the other hydraulic chamber of the shock absorber is connected to a control valve, and the control valve controls the flow of operating oil to the other hydraulic chamber in response to switching of the eccentric position of the eccentric sleeve. A variable compression ratio device for an internal combustion engine that sets a supply / exhaust state.