JP2007239520A - Variable compression ratio device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a clutch by inhibiting reverse input from a control shaft side to the clutch. <P>SOLUTION: A variable compression ratio device includes a rink train which consists of a plurality of links 21, 22 connecting a piston 14 reciprocating in a cylinder 12, a crank pin 17 of a crankshaft 16, a control shaft 23 of which rotary position is changed and retained by a drive part 33, and a control link 25 connecting the control shaft 3 and the link train, and changes piston stroke according to the rotary position of the control shaft 23. The clutch 43 shutting off reverse input from the control shaft 23 to the drive part 33 is put in a power transmission route from the drive part 33 to the control shaft 23. A final reduction gear 46 is put in a power transmission route from the clutch 43 to the control shaft 23. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable compression ratio device for an internal combustion engine that changes a piston stroke in accordance with a rotational position of a control shaft.

  For example, Patent Document 1 describes a variable compression ratio device that makes an engine compression ratio variable by changing a piston stroke of an internal combustion engine. In this device, a link train composed of a plurality of links (rods) linking a piston that reciprocates in a cylinder and a crankpin of a crankshaft, and an output side lever arm whose rotational position is changed and held by a drive unit such as a motor The shaft portion is linked by a control rod so that the piston stroke changes according to the rotational position of the shaft portion. In the power transmission path from the drive section to the shaft section, a clutch for interrupting reverse input of a load caused by in-cylinder pressure or the like from the link row side to the drive section side is interposed. Further, a speed reduction mechanism is interposed between the drive unit and the clutch.

The structure of the clutch is known as described in Patent Document 2, and briefly described. When reverse input from the link row side, that is, the output side is applied, a slight rotation of the output shaft is performed. A roller-shaped engagement element is engaged with the wedge surface (cam surface) with the movement, and the load on the output side is generated by a mechanical balance generated between the inner peripheral surface of the fixed outer ring and the wedge surface through the roller. Is cut off and cannot be transmitted to the input side.
JP 2005-30234 A JP 2003-343601 A

  However, in the above-mentioned Patent Document 1, since the load caused by the in-cylinder pressure or the like acts directly without being decelerated to the clutch through the link row, a large load is applied to the clutch. Will bear. Although the clutch disengagement ability varies depending on various factors such as the number of rollers, the roller diameter, and the roller length, it is held as the rotational torque of the output shaft, so that it is extremely advantageous that the output shaft has a large diameter. Therefore, in order to improve the clutch disengagement capability, it is desirable to increase the diameter and size of the clutch. However, such an increase in diameter and size of the clutch causes a decrease in vehicle mountability.

  Considering that the input shaft of the reverse input cutoff clutch is rotationally driven by the drive unit, the distance that the roller slides with the inner peripheral surface of the fixed outer ring becomes longer as the clutch becomes larger. Therefore, an increase in the clutch size (increase in diameter) leads to an increase in the clutch's load cutoff capability and an increase in friction loss of the drive part. Since the energy loss of the part becomes a significant loss to the fuel efficiency, it is a very big problem.

  Further, in the conventional example, a multi-link mechanism, a reverse input cutoff clutch, a speed reduction mechanism, and the like are laid out in parallel in the same crank chamber. That is, the engine oil is used to lubricate the reverse input shut-off clutch in the same manner as the crank system parts arranged in the crank chamber. As described above, the clutch disengagement ability depends on the engagement between the roller, the inner periphery of the fixed outer ring, and the wedge surface of the output shaft, that is, the frictional force. However, when the clutch structure is lubricated with engine oil scattered in the crank chamber, the anti-seizure effect of the extreme pressure additive generally added to the engine oil hinders the biting action of the roller. There is a concern that the reverse input blocking clutch may be hindered from operating normally.

  The present invention has been made in view of such a problem, and a rotational position is changed by a link row composed of a plurality of links that link a piston that reciprocates in a cylinder and a crankpin of a crankshaft, and a drive unit. In a variable compression ratio device for an internal combustion engine, having a control shaft to be held, and a control link that links the control shaft and the link row, the piston stroke changes according to the rotational position of the control shaft. A power transmission path from the drive unit to the control shaft is provided with a clutch for blocking reverse input from the control shaft to the drive unit, and a final reduction mechanism is provided on the power transmission path from the clutch to the control shaft. It is characterized by that.

  According to the present invention, since the final speed reduction mechanism is interposed in the power transmission path from the clutch to the control shaft, it is sufficient that a large reverse input caused by a combustion load or the like acts on the clutch from the control shaft side. Can be suppressed. Therefore, it is possible to reduce the size of the clutch and improve the engine mountability while ensuring the durability and reliability of the clutch.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a variable compression ratio device for an internal combustion engine according to an embodiment of the present invention, and corresponds to a cross-sectional view in a direction perpendicular to the crankshaft axis passing through the cylinder center of the in-line engine.

  In the cylinder block 11, a cylindrical cylinder 12 is formed for each cylinder, and a water jacket 13 is formed around each cylinder 12. A piston 14 is disposed in each cylinder 12 so as to be movable up and down. The piston pin 15 of each piston 14 and the crankpin 17 of the crankshaft 16 are a link row composed of a plurality of links, specifically, an upper. The link 22 and the lower link 21 are mechanically linked. Reference numeral 18 denotes a counterweight of the crankshaft 16. Specifically, the variable compression ratio device includes a lower link 21 that is attached to the crankpin 17 so as to be relatively rotatable, an upper link 22 that connects the lower link 21 and the piston pin 15, and a cylinder parallel to the crankshaft 16. A control shaft 23 extending in the column direction, an eccentric cam 24 provided eccentric to the control shaft 23, a control link 25 connecting the eccentric cam 24 and the lower link 21, and a control shaft 23 within a predetermined control range. And an actuator unit 30 including a motor 33 as a drive unit that is driven to rotate at a predetermined rotational position.

  The upper end portion of the rod-like upper link 22 is attached to the piston pin 15 of the piston 14 so as to be relatively rotatable, and the lower end portion is connected to the lower link 21 via the first connecting pin 26 so as to be relatively rotatable. . One end of the control link 25 is connected to the lower link 21 via the second connecting pin 27 so as to be relatively rotatable, and the other end of the control link 25 is attached to the outer periphery forming the cylindrical surface of the eccentric cam 24 so as to be relatively rotatable. ing. As shown in FIG. 2, the control shaft 23 has a plurality of main shafts 29 that are rotatably supported at the lower portion of the cylinder block 11. The rotation center P of the eccentric cam 24 is eccentric by a predetermined amount with respect to the rotation center Q of the main shaft 29.

  By rotating the control shaft 23 by the actuator unit 30 according to the engine operating state, the position of the swing fulcrum of the control link 25 fitted on the eccentric cam 24 changes, and the postures of the lower link 21 and the upper link 22 are changed. As a result, the compression ratio of the combustion chamber defined above the piston 14 is variably controlled. Such a variable compression ratio device is capable of continuously changing the engine compression ratio, and has a preferable piston stroke characteristic as compared with a single link mechanism in which the piston and the crank pin are connected by a single connecting rod. (For example, characteristics close to simple vibration). Further, since the control link 25 is connected to the lower link 21, the control link 25, the control shaft 23, and the actuator unit 30 can be arranged in the lower region of the crankshaft 16 having a relatively large space. Compared to the one described in Japanese Patent Application Laid-Open No. 2005-30234, the engine mounting property is excellent.

  FIG. 3 is a sectional view showing the actuator unit 30 as a single unit. The actuator unit 30 is mainly composed of a casing 40 that is fixed to the lower side of the cylinder block 11 and includes a plurality of parts 40A to 40C that are fixed to each other by bolts 42A, pins 42, and the like. The casing 40 is attached with the motor 33, and an actuator shaft 32 that engages with the control shaft 23 is supported so as to be able to reciprocate and slide in the axial direction. The drive torque of the motor 33 is transmitted to the control shaft 23 via Although not shown, an oil pan for storing lubricating oil is attached below the cylinder block 11 and the casing 40, and a crankshaft 16 or the like as a lubricating part is disposed above the oil pan. A crank chamber 19 is formed. The casing 40 functions as an outer wall of the crank chamber 19 that fluidly defines the crank chamber 19 together with the side wall of the cylinder block 11, and the casing 40 causes the actuator shaft 32 to move into the crank chamber 19. The motor 33 is held outside the cylinder block 11 while being slidably held in a faced position.

  The actuator unit 30 is provided with a clutch 43 that interrupts reverse input from the control shaft 23 side to the drive unit 33 side in the power transmission path from the motor 33 to the control shaft 23. A first reduction mechanism 44 is interposed in the power transmission path from the motor 33 to the clutch 43, and a second reduction mechanism 45 and a final reduction mechanism 46 are provided in the power transmission path from the clutch 43 to the control shaft 23. Is intervening.

  The first speed reduction mechanism 44 is fixed to the input shaft 44 of the clutch 33 and the first input side gear 44B fixed to the input shaft 2 of the clutch 43 and meshes with the first input side gear 44A. And a reduction gear train. The second reduction mechanism 45 includes a second input side gear 45A that is fixed to the output shaft 3 of the clutch 43, a second output side gear 45B that is provided on the outer periphery of the final gear 36 and meshes with the second input side gear 45A, It is a reduction gear train comprised by these. These gears are fixed using press-fitting or parallel keys.

  The final reduction mechanism 46 includes a feed screw mechanism 47 that converts the rotary motion of the final gear 36 into a reciprocating motion of the actuator shaft 32, a slider crank mechanism 48 that converts the reciprocating motion of the actuator shaft 32 into a rotary motion of the control shaft 23, have. As shown in FIG. 2, the feed screw mechanism 47 includes a male screw 35 formed at the end of the actuator shaft 32 on the motor side and a female screw 37 formed on the inner peripheral surface of the final gear 36 and meshing with the male screw 35. The rotational movement of the final gear 36 is converted into the reciprocating movement of the actuator shaft 32 and transmitted. The slider crank mechanism 48 converts the reciprocating motion of the actuator shaft 32 through the pin 39 into the rotational motion of the control shaft 23 and transmits it. The pin 39 is provided with small-diameter portions 39B on both sides of a large-diameter portion 39A that is rotatably fitted to one end (tip) of the actuator shaft 32 having a cylindrical shape. The small-diameter portion 39B is slidably fitted in a radially extending slit 41 formed in a pair of control plates 41A provided at one end of the control shaft 23. Therefore, when the actuator shaft 32 reciprocates, the control shaft 23 rotates in a predetermined direction via the control plate 41A while being accompanied by a sliding operation of the pin 39 in the slit 41.

  The clutch 43 is known as disclosed in Japanese Patent Application Laid-Open No. 2003-343601. Briefly described, the clutch 43 has a motor-side input shaft with respect to the stationary outer ring 1 as a stationary member fixed to the casing 40B. 2 and the output shaft 3 on the control shaft 23 side are supported so as to be rotatable forward and backward via rolling bearings 4A to 4D. The input shaft 2 and the output shaft 33A of the motor 33 are connected via the first reduction mechanism 44, and the output shaft 3 and the final gear 36 are connected via the second reduction mechanism 45. . The fixed outer ring 1 is stably fixed to the casing 40 by press-fitting or using a parallel key.

  As shown in FIGS. 4 and 5, the input shaft 2 is provided with a through hole 6 along the axial direction at a position shifted radially outward from the shaft center, and the output shaft 3 includes the input shaft 2 and A concave groove 7 is formed along the radial direction on the opposite end face. By inserting a pin 8 into the through-hole 6 of the input shaft 2, projecting the tip of the pin 8 from the end surface facing the output shaft 3, and fitting it into the groove 7 formed on the end surface of the output shaft 3, The rotational torque from the input shaft 2 can be transmitted to the output shaft 3. A flange portion 2a whose diameter is increased radially outward is integrally formed at the output shaft side end portion of the input shaft 2, and serves as a cage continuously extending from the outer periphery of the flange portion 2a to the output shaft side in the axial direction. A plurality of column portions 2b are formed at equal intervals in the circumferential direction. The space between the column portions 2b adjacent to each other in the circumferential direction constitutes a pocket 9 that is open toward one side in the axial direction, and a pair of rollers 10a and 10b is disposed in each pocket 9, respectively. A plurality of pairs of cam surfaces (wedge surfaces) 9a, 9b are formed at equal intervals in the circumferential direction on the input shaft side outer periphery of the output shaft 3 so as to correspond to the pockets 9 positioned between the column portions 2b of the input shaft 2 described above. Has been. A plurality of pairs of rollers 10a and 10b are respectively disposed between the cam surfaces 9a and 9b of the output shaft 3 and the inner peripheral surface of the fixed outer ring 1, and the pockets 9 formed between the column portions 2b of the input shaft 2 are provided. Be contained. An elastic member 5 such as a spring is inserted between the pair of rollers 10a and 10b, and the elastic member 5 elastically presses the pair of rollers 10a and 10b away from each other. Each elastic member 5 is inserted and disposed between the pair of rollers 10 a and 10 b independently of the input shaft 2, the output shaft 3 and the fixed outer ring 1.

  When the reverse input torque in the clockwise direction is input to the output shaft 3 in the neutral state shown in an enlarged view in FIG. 6A, the reverse input cutoff clutch 43 is counterclockwise (rotated) by the elastic force of the elastic member 5. The roller 10a (backward in the direction) is engaged with the wedge gap in that direction, and the output shaft 3 is locked in the clockwise direction with respect to the fixed outer ring 1. Conversely, when counterclockwise reverse input torque is input to the output shaft 3, the roller 10b in the clockwise direction (backward in the rotational direction) is engaged with the wedge gap in that direction by the elastic force of the elastic member 5, and the output is output. The shaft 3 is locked counterclockwise with respect to the fixed outer ring 1. Therefore, the reverse input torque from the output shaft 3 is locked in both forward and reverse rotation directions by the pair of rollers 10a and 10b.

  On the other hand, when rotational torque is input to the input shaft 2 and rotated clockwise, for example, as shown in an enlarged view in FIG. 6B, first, the column portion of the input shaft 2 in the counterclockwise direction (backward in the rotational direction). 2b engages with the roller 10a in that direction (backward in the rotational direction) and presses it in the clockwise direction (forward in the rotational direction) against the elastic force of the elastic member 5. As a result, the counterclockwise (backward in the rotational direction) roller 10a is released from the wedge gap in that direction, the locked state of the output shaft 3 is released, and the output shaft 3 can be rotated clockwise. When the input shaft 2 further rotates clockwise, the pin 8 of the input shaft 2 comes into contact with the wall surface of the concave groove 7 of the output shaft 3 as shown in FIG. Rotational torque in the direction is transmitted to the output shaft 3 through the engaging portion between the pin 8 and the groove 7, and the output shaft 3 rotates clockwise. At this time, the roller 10b in the clockwise direction (forward in the rotation direction) does not engage with the wedge clearance in that direction, and idles in a state where the cam surface of the output shaft 3 and the inner peripheral surface of the fixed outer ring 1 are in contact. When a counterclockwise rotational torque is input to the input shaft 2, the output shaft 3 rotates counterclockwise by the reverse operation to that described above. Accordingly, the rotational torque in the forward and reverse rotational directions from the input shaft 2 is transmitted to the output shaft 3 through the engaging portion between the pin 8 and the concave groove 7, and the output shaft 3 rotates in the forward and reverse rotational directions. To do.

  Here, when the lock is released, the roller needs to be separated from the wedge gap as described above. However, when the output shaft can rotate excessively smoothly during this operation, the roller is separated from the wedge gap. Without rotating, it may rotate with the output shaft and may not be unlocked. For this reason, in order to smoothly perform the unlocking operation, a predetermined amount of rotational resistance (frictional force or the like) is applied to the output shaft 3. In the example of FIG. 7, the oil seal 49 is disposed on the output shaft 3 side to add resistance in the rotational direction. The oil seal 49 is basically interposed between the outer periphery of the second input side gear 45A of the second reduction mechanism 45 fixed to the output shaft 3 and the casing 40, and seals this portion. Thus, the resistance addition in the rotational direction is realized with a simple configuration using the oil seal 49.

  As described above, since the rotation of the output shaft 33A of the motor 33 is sufficiently decelerated and transmitted to the control shaft 23 by the first reduction mechanism 44, the second reduction mechanism 45, and the final reduction mechanism 46, the control shaft The reverse input torque acting on the motor 33 from the side can be greatly suppressed, and the motor 33 can be reduced in size and output, and the reverse input from the control shaft 23 side to the motor 33 side can be interrupted by the clutch 43. can do. In this embodiment, since the second reduction mechanism 45 and the final reduction mechanism 46 are interposed between the clutch 43 and the control shaft 23, the reverse input from the control shaft 23 side to the clutch 43 side is suppressed. can do. Therefore, it is possible to reduce the size of the clutch 43 and improve the engine mountability while ensuring the shut-off ability, reliability, and durability of the clutch 43.

  In addition, the screwing action of the feed screw mechanism 47 can more reliably prevent the actuator shaft 32 from being inadvertently rotated due to reverse input from the control shaft 23.

  The clutch 43 and the speed reduction mechanisms 44 to 46 are accommodated in the casing 40 except for the tip of the actuator shaft 32 protruding into the crank chamber 19. A seal member 50 is attached to the outer periphery of the actuator shaft 32 to seal a gap with the cylindrical inner periphery of the casing 40A. As this seal member, for example, various members such as an oil seal, a lip seal, and a labyrinth packing can be used in addition to an O-ring as illustrated. By such a seal member 50 and the oil seal 49 described above, the internal space of the casing 40 in which the clutch 43 and the speed reduction mechanisms 44 to 46 are disposed is liquid-tightly separated from the crank chamber 19. Therefore, the internal space of the casing 40 in which the clutch 43 and the speed reduction mechanisms 44 to 46 are disposed is lubricated by using a dedicated lubricant such as grease, in addition to the engine oil (lubricating oil) scattered in the crank chamber 19. The lubrication performance of the clutch 43 and the speed reduction mechanisms 44 to 46 can be greatly improved as compared with the case where the engine oil is lubricated in the same manner as the crankshaft or the like. Therefore, it is possible to further reduce the size of the clutch 43 while ensuring the load blocking capability of the clutch 43 and minimizing the load on the motor 33 side.

  7 and 8, the second embodiment shown in FIGS. 7 and 8 is integrally connected to the output shaft 3 between a pair of rollers (engagement members) 10a and 10b as compared with the first embodiment shown in FIGS. 7 is different from the first embodiment of FIG. 7 in that an elastic member 5a, 5b is interposed between the partition member 51 and the rollers 10a, 10b. The mechanism for transmitting the rotational torque acting on the input shaft 2 to the output shaft 3 is the same as that in the first embodiment, but the roller 10a, 10b rotates while being pressed during the operation. For this reason, in the structure in which the pressing force acting on one roller continues to act on the other roller via the elastic member as in the first embodiment, the other roller is brought into contact with the inner peripheral portion of the fixed outer ring 1 by this transmission force. It always acts as a frictional force. This acting force becomes the frictional resistance force of the drive unit as it is, and becomes the energy resistance at the drive unit. The structure for reducing and avoiding such problems is the reverse input cutoff clutch with the partition member of the second embodiment. By arranging such a partition member 51, rotational torque (tangential force) acting on one roller acts on one elastic member, but since the tangential force is blocked by the partition member 51, the other elasticity There is no tangential force acting on the member. Therefore, the frictional force with the inner peripheral surface of the fixed outer ring 1 caused by the tangential force acting on the other roller can be remarkably reduced, and the energy consumption of the drive unit can be greatly reduced and avoided. This structure itself is known as disclosed in Japanese Patent Laid-Open No. 2003-343601.

  Next, with reference to FIGS. 9 and 10, the effect of reducing the reverse input acting on the output shaft of the clutch will be described. FIG. 9 corresponds to the variable compression ratio apparatus of the comparative example (see Japanese Patent Application Laid-Open No. 2005-30234), and FIG. 10 corresponds to the variable compression ratio apparatus according to the above embodiment.

  In the comparative example shown in FIG. 9, the piston 61 and the crank pin 62 are linked by two links (rods) 63 and 64, and the connection pin 65 and the control shaft (the shaft portion of the lever arm) of both the links 63 and 64. 66) are connected by a control link (rod) 67. The control shaft 66 is configured to rotate integrally with the output shaft 69 of the reverse input cutoff clutch 68, and no speed reduction mechanism is interposed between the clutch and the control shaft as in this embodiment. . A speed reduction mechanism 70 is interposed between the drive unit (not shown) and the clutch 68. The speed reduction mechanism 70 and the clutch 68 are arranged in parallel in the crank chamber 71 and are lubricated by engine oil. It has become.

Here, the load input to the reverse input cutoff clutch 68 when the load due to the combustion pressure is F and the illustrated posture is the link posture at the top dead center of the piston was approximated. Originally, dynamic inertial forces and dead weights of link mechanism parts and the like should be taken into account, but for the sake of simplicity, static load when the load F due to the combustion pressure acts as a static load at the top dead center is here. Organized as a balance of power. If the angle formed by the axial direction of the upper link 63 and the engine vertical direction is θ1, and the angle formed by the control link 67 and the engine horizontal direction is θ2, the force F acting on the piston crown surface causes the upper link 63 to move in the axial direction. The acting load component F1 is
F1 = F · cos θ1
It becomes. Furthermore, due to F1, the load component F2 acting in the engine horizontal direction via the pin 65 is:
F2 = F1 · sin θ1
It becomes. Therefore, the load component Fc acting in the axial direction of the control link 67 is
Fc = F2 · cos θ2
= F1 · sinθ1 · cosθ2
= F · sinθ1 · cosθ1 · cosθ2
It becomes.

Assuming that θ1 is 10 deg and θ2 is 13 deg in the illustrated link posture,
Fc = F × 0.167
Thus, approximately 17% of the combustion load acting on the piston crown surface acts on the output shaft of the reverse input cutoff clutch 68 as a reverse input torque.

Next, with reference to FIG. 10, it is estimated how much the load acts on the reverse input cutoff clutch 43 by the combustion pressure in the variable compression ratio device of the present embodiment. The force F acting on the piston crown surface is converted into a load F1 in the axial direction of the upper link. Where F1 is
F1 = F · cos θ1
It becomes. This F1 acts on the connecting portion of the upper link and the lower link, that is, the first connecting pin 26, but the component force F2 in the direction perpendicular to the line segment L1 connecting the first connecting pin 26 and the center of the crankpin 17 If the angle between F1 and F2 is θ2,
F2 = F1 · cos θ2
It becomes. Since the force F3 of the component in the direction perpendicular to the link center line L2 of the control link acting on the second connecting pin 27 and the F2 have a moment balance relation around the crankpin 17,
F2 / L1 = F3 / L2
F3 = F2 (L1 / L2)
It becomes. Here, if the force acting in the axial direction of the control link from the lower link side is F4, and the angle formed by F3 and F4 is θ3,
F4 = F3 · cos θ3
It becomes. From the above, F4 is
F4 = F2 (L1 / L2) cos θ3
= F1 (L1 / L2) cosθ2 · cosθ3
= F (L1 / L2) cosθ1 · cosθ2 · cosθ3
It becomes. Assuming that L1 is 45 mm, L2 is 65 mm, θ1 is 6 deg, θ2 is 40 deg, and θ3 is 33 deg.
F4 = 0.442 × F
It becomes. From the balance of moments of F4 and F5 around the center of the control shaft,
F4 ・ L3 = F5 ・ L4
F5 = F4 (L3 / L4)
It becomes. Suppose here that
When L3 = 10 mm and L4 = 40 mm,
F5 = 0.25 × F4
= 0.11 × F
It becomes.

When the reverse efficiency ηb in the above feed screw mechanism is 0.95 and the final reduction gear ratio Zf is 0.25, the tangential reverse input Fc acting on the output shaft of the reverse input cutoff clutch 43 is:
Fc = ηb × Zf × F5
= 0.95 x 0.25 x 0.11 x F
= 0.026 x F
It becomes. Therefore, compared with the comparative example of FIG. 9, the reverse input acting on the reverse input cutoff clutch can be remarkably reduced to about 85%.

  The characteristic technical idea of the present invention that can be understood from the above description will be described with reference to the above-described embodiment. However, the present invention is not limited to the above-described embodiments, and includes various modifications and changes without departing from the spirit thereof. For example, the drive unit is not limited to the electric motor 33 as in the above embodiment, but may be a hydraulic drive type.

  (1) A link row composed of a plurality of links 21 and 22 linking the piston 14 reciprocating in the cylinder 12 and the crankpin 17 of the crankshaft 16, and a control shaft whose rotational position is changed and held by the drive unit 33. 23 and a control link 25 that links the control shaft 23 and the link train, and the piston stroke changes according to the rotational position of the control shaft 23. A clutch 43 for interrupting reverse input from the control shaft 23 to the drive unit 33 is interposed in the power transmission path from the part 33 to the control shaft 23, and the power transmission path from the clutch 43 to the control shaft 23 is finally connected to the power transmission path. A speed reduction mechanism 46 is interposed.

  Since the final speed reduction mechanism 46 is interposed in the power transmission path from the clutch 43 to the control shaft 23 in this way, a high reverse input due to combustion pressure or the like acts on the clutch 43 from the control shaft 23 side. It can be sufficiently suppressed. Therefore, it is possible to reduce the size of the clutch 43 and improve the engine mountability while ensuring the disconnection ability, durability, and reliability of the clutch 43. Further, along with the downsizing of the clutch 43, for example, by reducing the moment of inertia at the time of driving the clutch by reducing the number of rollers, it is possible to reduce energy loss such as frictional force by the drive unit 33, and to further reduce energy consumption. Can be suppressed. Particularly, in the case of an internal combustion engine mounted on a vehicle, the fuel efficiency of the vehicle can be greatly improved by suppressing energy consumption, which is extremely useful.

  (2) The final speed reducing mechanism 46 converts the rotational motion of the output shaft 3 of the clutch 43 into the reciprocating motion of the actuator shaft 32 by the engagement of the male screw 35 and the female screw 37, and the reciprocating motion of the actuator shaft 32. And a mechanism 48 that converts the rotation into the rotational motion of the control shaft 23.

  Thus, according to the final reduction mechanism 46, a significant reduction effect can be obtained, and the reverse input from the actuator shaft 32 to the clutch 43 side can be more reliably suppressed / blocked by the screwing action of the feed screw mechanism 47. Can do.

  In addition, examples of the feed screw include a square screw, a trapezoidal screw, and a ball screw. However, the ball screw is most efficient in both forward and reverse efficiency, and it is desirable to use a ball screw. The reverse efficiency is the efficiency in the direction in which the load input from the in-cylinder pressure of the engine acts on the drive unit side in the structure of the present invention. When this reverse efficiency is high and there is no effective means for blocking reverse input, it is necessary to cover almost all as a holding force by the drive unit. In the present invention, in the normal efficiency rotation direction driven from the drive unit, it can be driven with the minimum energy because of its high efficiency, and in the reverse efficiency rotation direction, the efficiency of the feed screw is high, but the reverse as described above. By using the input cutoff clutch 43, the influence on the energy consumption of the drive unit can be substantially eliminated.

  (3) The drive unit 33 is attached to the actuator unit 30 attached to the cylinder block 11, and the actuator shaft 32 is slidably supported. In the actuator unit 30, the clutch 43 and the final reduction mechanism 46 are accommodated. As described above, the drive unit 33, the clutch 43, the final speed reduction mechanism 46, the actuator shaft 32, and the like are unitized as the actuator unit 30, thereby making it possible to reduce the size and improve the engine mountability.

  (4) The tip of the actuator shaft 32 that engages with the control shaft 23 is disposed in the crank chamber 19 where the lubricating oil scatters. A seal member 50 that seals the internal space of the actuator unit 30 in which the clutch 43 and the final reduction mechanism 46 are housed from the crank chamber 19 is provided.

  By disposing the reverse input cut-off clutch 43 inside the actuator unit 30 that is liquid-tightly separated from the crank chamber 19, the reverse input cut-off is independent of the lubrication environment by the engine oil as the lubricating oil in the crank chamber 19. An optimum lubricant (for example, grease) can be used for the clutch 43. For this reason, compared to using engine oil to lubricate the clutch, there is no problem that the user does not know what oil to use when changing the oil, and there is no risk of injecting commercially available additives. The free holding can be promoted and a stable lubricating property can be secured, so that the clutch holding performance can be stabilized. In addition, there is no concern about deterioration of the clutch performance due to generation of contamination (impurities) or oil deterioration due to carbon or the like, which is a concern when the clutch is lubricated with engine oil. Therefore, by greatly improving the lubrication performance of the clutch and promoting the downsizing of the clutch, it is possible to further suppress the energy burden on the drive unit while ensuring the load blocking capability.

  (5) A first reduction mechanism 44 is interposed between the drive unit 33 and the clutch 43, and a second reduction mechanism 45 is interposed between the clutch 43 and the final reduction mechanism 46, thereby reducing the speed. The ratio can be further increased. The first and second speed reduction mechanisms 44 and 45 are housed and arranged in the actuator unit 30 together with the clutch 43 and the final speed reduction mechanism 46, and can be made compact and improved in engine mountability. As with the clutch 43, the lubricating performance of the first and second reduction mechanisms 44 and 45 can be improved.

  (6) The clutch 43 includes an input shaft 2 connected to the drive unit 33 side, an output shaft 3 connected to the control shaft 23 side, a stationary side member (fixed outer ring) 1 whose rotation is restricted, A pair of engagement elements 10a, 10b provided between the stationary member 1 and the output shaft 3 so as to be able to be disengaged and a pair of engagement elements 10a, 10b are disposed between the stationary member 1 and the output shaft 3. An elastic member 5 that is biased in the direction of engagement with the shaft 3, locks the output shaft 3 and the stationary member 1 against reverse input from the output shaft 3, and inputs from the input shaft 2. The lock state is released with respect to the torque.

  More specifically, the reverse input cut-off clutch 43 pushes the rollers 10a and 10b as the engaging members by the column portion 2b of the input shaft 2 and wedges the rollers engaged with the wedge surfaces (cam surfaces) 9a and 9b. The locked state is released by removing the surfaces 9a and 9b. For this releasing operation, it is important that the output shaft 3 is not easily rotated when the roller is pushed. If the output shaft 3 can rotate excessively smoothly, when the column portion 2b presses the roller, the engagement of the roller cannot be released, and the output shaft 3 may rotate while the roller is engaged. .

  (7) Therefore, preferably, a means for applying a predetermined resistance to the output shaft 3 of the clutch 43 is provided as in the oil seal 49 described above. In this way, by applying a predetermined resistance to the output shaft 3, the roller can be instantaneously separated and the lock can be released smoothly. The above resistance (frictional force) may be extremely small, and the energy loss is sufficiently low. Further, since the first reduction mechanism 44 is interposed between the drive unit 33 and the clutch 43 as described above, the influence of the energy consumption by the urging means is the reduction ratio by the first reduction mechanism 44. Therefore, the level is substantially negligible.

  (8) As described above, in the configuration in which the reverse input to the drive unit is suppressed to be extremely low by the clutch or the speed reduction mechanism, for example, in order to avoid abnormal combustion such as knocking, the operation responsiveness becomes rather important. Therefore, it is necessary to reliably and instantaneously release the lock of the clutch 43 described above.

  Here, in the clutch 43 as in the first embodiment shown in FIG. 4 and FIG. 5, when the clutch 43 is rotated by the torque in the positive direction from the drive unit, the column portion 2 b integrated with the input shaft 2 The engaging member (roller) is pressed by a small angle, and the other engaging member is pressed through the elastic member 5 to operate. Therefore, the pressed other engaging member is configured to be rotated while generating a constant frictional force with the inner peripheral surface of the stationary member 1. This frictional force is nothing but the energy loss of the drive unit.

  Therefore, in the second embodiment shown in FIGS. 7 and 8, a partition member 51 fixed to the output shaft 3 is provided between the pair of engagement elements, and the partition member 51 and each engagement element are respectively provided. Elastic members 5a and 5b are provided. According to this configuration, the partition member 51 disposed between the pair of engagement elements causes the pressing force of the elastic member that acts on one engagement element and the other engagement element when torque is transmitted from the input shaft 2 side. The pressing force of the acting elastic member can be made almost independent. Therefore, the above-mentioned energy loss can be reduced, and the fuel efficiency can be improved particularly when applied to an automobile.

  (9) A lower link 21 attached to the crankpin 17 of the crankshaft 16, an upper link 22 that links the lower link 21 and the piston 14, an eccentric cam 24 provided eccentrically on the control shaft 23, A control link 25 that links the eccentric cam 24 and the lower link 21 is provided. According to such a structure, in addition to the ability to continuously change the engine compression ratio, the piston stroke characteristic itself is a preferable characteristic (compared to a single link mechanism in which the piston and the crank pin are connected by a single connecting rod) ( For example, it can be set to a characteristic close to simple vibration. Further, since the control link 25 is connected to the lower link 21, the control link 25, the control shaft 23, the actuator unit 30 and the like can be arranged in a lower region of the crankshaft 16 having a relatively large space, Excellent in engine mounting.

1 is a cross-sectional view showing an example of a variable compression ratio device for an internal combustion engine according to the present invention. The disassembled perspective view which shows the final deceleration mechanism of the said variable compression ratio apparatus. Sectional drawing which shows the actuator unit of the said variable compression ratio apparatus. Sectional drawing which follows the ZZ line | wire of FIG. 5 which shows the clutch of 1st Example of this invention. Sectional drawing which follows the YY line of FIG. 4 which shows the clutch of the said 1st Example. The operation explanatory view of the above-mentioned clutch. Sectional drawing which follows the AA line of FIG. 8 which shows the clutch of 2nd Example of this invention. Sectional drawing which follows the XX line of FIG. 7 which shows the clutch of the said 2nd Example. Explanatory drawing for demonstrating the reverse input which acts on the clutch of a comparative example. Explanatory drawing for demonstrating the reverse input which acts on the clutch of the said Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 12 ... Cylinder 14 ... Piston 16 ... Crankshaft 17 ... Crankpin 21 ... Lower link 22 ... Upper link 23 ... Control shaft 25 ... Control link 33 ... Drive part 43 ... Clutch 46 ... Final reduction mechanism 47 ... Feed screw mechanism 48 ... Slider Crank mechanism

Claims (9)

A link row composed of a plurality of links linking a piston that reciprocates in the cylinder and a crank pin of the crankshaft, a control shaft whose rotational position is changed and held by a drive unit, and a link between the control shaft and the link row A variable compression ratio device for an internal combustion engine, wherein the piston stroke changes according to the rotational position of the control shaft.
A clutch that interrupts reverse input from the control shaft to the drive unit is interposed in the power transmission path from the drive unit to the control shaft, and a final reduction mechanism is installed in the power transmission path from the clutch to the control shaft. A variable compression ratio device for an internal combustion engine, characterized by comprising: The final deceleration mechanism is
A feed screw mechanism that converts the rotational movement of the output shaft of the clutch into the reciprocating movement of the actuator shaft by the engagement of the male screw and the female screw;
A mechanism for converting the reciprocating motion of the actuator shaft into the rotational motion of the control shaft;
The variable compression ratio device for an internal combustion engine according to claim 1, characterized by comprising:   The drive unit is attached to the actuator unit attached to the cylinder block, and the actuator shaft is slidably supported. The clutch and the final reduction mechanism are accommodated in the actuator unit. The variable compression ratio device for an internal combustion engine according to claim 2, wherein: The tip of the actuator shaft that engages with the control shaft is disposed in the crank chamber where the lubricating oil scatters,
The variable compression ratio device for an internal combustion engine according to claim 3, further comprising a seal member that seals an internal space of the actuator unit in which the clutch and the final reduction mechanism are housed from the crank chamber. A first reduction mechanism is interposed between the drive unit and the clutch, and a second reduction mechanism is interposed between the clutch and the sampling reduction mechanism.
4. The variable compression ratio device for an internal combustion engine according to claim 2, wherein the first and second speed reduction mechanisms are accommodated in the actuator unit together with the clutch and the final speed reduction mechanism.   The clutch includes an input shaft connected to the drive unit side, an output shaft connected to the control shaft side, a stationary side member whose rotation is restricted, and a disengagement between the stationary side member and the output shaft. A pair of engaging elements provided in a possible manner, and an elastic member that is disposed between the pair of engaging elements and biases them in a direction of engaging both between the stationary member and the output shaft. 6. The internal combustion engine according to claim 1, wherein the output shaft and the stationary side member are locked with respect to the reverse input, and the locked state is released with respect to the input torque from the input shaft. Variable compression ratio device. 7. The variable compression ratio device for an internal combustion engine according to claim 6, further comprising means for applying a predetermined resistance in the rotational direction to the output shaft of the clutch.   8. A partition member fixed to an output shaft is provided between the pair of engagement elements, and an elastic member is disposed between the partition member and each engagement element. Variable compression ratio device for internal combustion engine. A lower link attached to the crankpin of the crankshaft,
An upper link that links the lower link and the piston;
An eccentric cam provided eccentric to the control shaft;
A control link that links the eccentric cam and the lower link;
The variable compression ratio device for an internal combustion engine according to any one of claims 1 to 8, characterized by comprising:

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