US20100122678A1 - Valve driving apparatus - Google Patents
Valve driving apparatus Download PDFInfo
- Publication number
- US20100122678A1 US20100122678A1 US12/617,756 US61775609A US2010122678A1 US 20100122678 A1 US20100122678 A1 US 20100122678A1 US 61775609 A US61775609 A US 61775609A US 2010122678 A1 US2010122678 A1 US 2010122678A1
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- US
- United States
- Prior art keywords
- cam
- driving apparatus
- valve driving
- swing arm
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0021—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of rocker arm ratio
- F01L13/0026—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of rocker arm ratio by means of an eccentric
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/02—Valve drive
- F01L1/04—Valve drive by means of cams, camshafts, cam discs, eccentrics or the like
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
- F01L1/12—Transmitting gear between valve drive and valve
- F01L1/18—Rocking arms or levers
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0021—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of rocker arm ratio
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L13/00—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L13/0015—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque
- F01L13/0063—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of cam contact point by displacing an intermediate lever or wedge-shaped intermediate element, e.g. Tourtelot
- F01L2013/0068—Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations for optimising engine performances by modifying valve lift according to various working parameters, e.g. rotational speed, load, torque by modification of cam contact point by displacing an intermediate lever or wedge-shaped intermediate element, e.g. Tourtelot with an oscillating cam acting on the valve of the "BMW-Valvetronic" type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F01L2820/00—Details on specific features characterising valve gear arrangements
- F01L2820/03—Auxiliary actuators
- F01L2820/032—Electric motors
Definitions
- the present invention relates to a valve driving apparatus and, more particularly, to a valve driving apparatus that is capable of continuously adjusting lift amounts of valves opening and closing a combustion chamber of an internal combustion engine with a double-cam unit to provide optimum fuel economy and output.
- an internal combustion engine of vehicles includes a combustion chamber in which fuel is burned to generate power.
- the combustion chamber is provided with a valve train, which includes intake/exhaust valves controlling the flow of intake and exhaust gases and is associated with a crankshaft to open and close the combustion chamber.
- the valve In a typical valve train, the valve is open in a constant lift amount by a cam having a predetermined configuration, so that the amount of intake or exhaust gas is restricted to a constant amount.
- time and degree of valve opening are insufficient in high-speed drive conditions, and with a design contemplated for the high speed drive conditions, a reverse phenomenon occurs in the low speed drive conditions.
- a general internal combustion engine tuned for high speed driving is set to have a high valve lift value, it exhibits good performance under high-speed conditions, but is very disadvantageous in terms of idle stability and low-speed torque characteristics under low speed conditions.
- the engine tuned for low speed driving provides good idle stability and low-speed torque under low-speed conditions but exhibits limited performance under high-speed conditions.
- a variable valve lift technique varies the lift amount of the valve corresponding to the high-speed and low-speed conditions, thereby providing merits both under low-speed and high-speed conditions.
- variable induction system VIS
- VVT variable valve timing
- VVL variable valve lift
- the present invention is conceived to solve the above problems of the related art, and an aspect of the invention is to provide a valve driving apparatus that is capable of precisely adjusting lift amounts of valves periodically opening and closing a combustion chamber of an internal combustion engine with a double-cam unit associated therewith in order to achieve optimum fuel economy and output.
- a valve driving apparatus includes: at least one swing arm having one side corresponding to an upper side of a valve opening and closing a combustion chamber of an internal combustion engine; and a cam unit periodically pivoting the swing arm.
- the swing arm performs a swing motion on the other side thereof by external manipulation to periodically compress the valve.
- the cam unit may include: a pivot member acting as a reference axis of the cam unit; a web member formed on the pivot member; a high rotary shaft forcibly rotated by an external force; a high lift cam formed on the high rotary shaft and including a high eccentric rod eccentrically rotated during rotation of the high rotary shaft; and a sub-cam unit connected to the web member and simultaneously operating one or more swing arms through the high eccentric rod during rotation of the high lift cam.
- the sub-cam unit may include: a low rotary shaft rotatably connected to the web member; a cam body formed on the low rotary shaft; a follow arm formed on the cam body to be rotated in a direction of the swing arm by periodic compression of the high eccentric rod; a low lift cam formed on the low rotary shaft and including a low eccentric rod to periodically compress one side of each of the swing arms at the same time during rotation of the follow arm; and an elastic member elastically supporting the cam body.
- the cam body may include the same number of low lift cams at opposite sides of the follow arm.
- the follow arm may be provided with a rotatable follow roller at a portion thereof where the follower arm directly contacts the high lift cam.
- the low lift cam may include a contact surface formed to support a center of each of the swing arm.
- the swing arm may include a rotatable swing roller disposed at a portion thereof contacting the contact surface.
- the follow arm and the low lift cam may be extended from the cam body in different directions from each other.
- the web member may be rotatably connected to the link shaft, and the link shaft may be connected to an actuation unit.
- the actuation unit may include: a connecting rod connected to the link shaft; a link pin linked to the connecting rod; a screw member linked to the link pin and linearly reciprocating in a perpendicular direction to an axis of the link shaft to reciprocate the link shaft on the arcuate track; and a power transmission member formed around a circumference of the screw member and reciprocating the screw member in a forward and rearward direction when the power transmission member is forcibly rotated by an external force.
- the actuation unit may include: an actuator having a receiving groove that receives the link shaft therein; and a screw member screwed to the actuator and linearly reciprocating the actuator in a forward and rearward direction to guide reciprocation of the link shaft on an arcuate track when the screw member is forcibly rotated by an external force.
- the elastic member may be supported at one side thereof by the link shaft and at the other side thereof by the cam body.
- the sub-cam unit may be received in a housing, and the sub-cam unit and the housing may include oil passages connected to each other between the sub-cam unit and the housing to receive a lubricant from outside through the oil passages.
- FIG. 1 is a side section view of a valve driving apparatus mounted in a housing in accordance with one embodiment of the present invention
- FIGS. 2 and 3 are perspective views of connection between components of the valve driving apparatus in accordance with the embodiment of the present invention.
- FIG. 4 is an exploded perspective view of the valve driving apparatus in accordance with the embodiment of the present invention.
- FIGS. 5 to 8 are operational diagrams of the valve driving apparatus in accordance with the embodiment of the present invention.
- FIG. 9 is a perspective view of a valve driving apparatus in accordance with another embodiment of the present invention.
- FIG. 10 shows oil passages formed in a valve driving apparatus in accordance with one embodiment of the present invention.
- a valve driving apparatus includes swing arms 100 and a cam unit 300 , which can variably control lift amounts of valves 20 opening and closing a combustion chamber 10 in an internal combustion engine.
- Each of the swing arms 100 has one side corresponding to an upper side of the valve 20 , which opens and closes the combustion chamber 10 , and performs a swing motion on the other side thereof by external manipulation to directly compress the valve 20 in a periodic manner.
- the swing arm 100 generates a constant profile of oscillation to allow the valve 20 to reciprocate in an up-down direction in a constant period. Accordingly, as the swing arm 100 rotates about the other side thereof to allow the one side thereof to periodically compress an upper side of the valve 20 , the valve 20 can be open or closed, that is, reciprocate in the up-down direction.
- the swing arm 100 is provided at the one side thereof with the valve 20 to face a lower surface of the one side in the longitudinal direction of the swing arm 100 , and at the other side thereof with a stationary support member 200 to face a lower surface of the other side thereof.
- the other side of the swing arm 100 is supported by a support member 200 such that the swing arm 100 can rotate about the other side thereof.
- the swing arm 100 is capable of rotating about the other side center P 1 supported by the support member 200 .
- an imaginary center line L 1 connecting the other side center P 1 with one side center P 2 of the swing arm 100 is reciprocatively pivoted about the other side center P 1 in a predetermined range of pivot angles.
- the support member 200 is securely mounted on a housing 30 .
- a common structure may be used to mount the support member 200 on the housing 30 .
- the swing arm 100 is supportively connected to the support member 200 and the valve 20 , the swing arm 100 is not easily vibrated or displaced.
- the housing 30 is formed at an upper side of the combustion chamber 10 .
- Various modifications may be made to the swing arm 100 and the support member 200 .
- the cam unit 300 serves to periodically pivot the swing arm 100 .
- the cam unit 300 includes a pivot member 310 , web members 320 , a high rotary shaft 330 , a high lift cam 340 , and a sub-cam unit 350 .
- the pivot member 310 acts as a reference axis of the cam unit 300 .
- the pivot member 310 is secured inside the housing 30 .
- a single pivot member 310 may be provided to one inner side of the housing 30 , but two pivot members 310 may be provided to opposite inner sides of the housing 30 to firmly support the web members 320 , respectively.
- each of the web members 320 is rotatably connected to the corresponding pivot member 310 .
- each of the pivot members 310 is rotatably fitted into the corresponding web member 320 , which is rotated about the pivot member 310 .
- the web members 320 may be integrally formed with the pivot members 310 .
- the pivot member 310 is shown as having a shaft shape, but various modifications may be made to the pivot member 310 .
- the web member 320 is connected to the corresponding pivot member 310 .
- the pivot member 310 is rotatably inserted into a lower side of the web member 320 .
- the web member 320 can be rotated about the pivot member 310 .
- the pivot members 310 may be rotatably mounted on the housing 30 .
- the web member 320 is shown as having a plate shape, but various modifications may be made to the web member 320 .
- the high rotary shaft 330 is forcibly rotated by an external force.
- the high rotary shaft 330 is supported by the housing 30 . That is, opposite ends of the high rotary shaft 330 are rotatably supported on the opposite sides of the housing 30 , respectively. With this configuration, the high rotary shaft 330 can be firmly supported.
- the high rotary shaft 330 is provided with the high lift cam 340 .
- the high lift cam 340 has a high eccentric rod 342 extending from one side thereof. With this configuration, the high lift cam 340 eccentrically rotates. In other words, at any time when the high lift cam 340 is rotated about its rotational axis P 3 to position the high eccentric rod 342 extending from one side thereof at a predetermined location on the circumference thereof, the high eccentric rod 342 compresses the swing arms 100 and follow arms 353 of the cam unit 300 described below, so that the valves 20 opens and closes the combustion chamber 10 while reciprocating in the up-down direction.
- the high lift cam 340 rotates in the same direction and at the same speed as those of the high rotary shaft 330 .
- the high lift cam 340 may be separably coupled to the high rotary shaft 330 or may be integrally formed therewith by molding.
- the separable coupling of the high lift cam 340 to the high rotary shaft 330 may be achieved by bolts and the like, particularly, by diffusion bonding.
- the sub-cam unit 350 is connected to the web members 320 .
- the sub-cam unit 350 serves to simultaneously operate one or more swing arms 100 in cooperation with the high eccentric rod 342 during rotation of the high lift cam 340 .
- the sub-cam unit 350 includes a low rotary shaft 351 , a cam body 352 , the follow arms 353 , low lift cams 355 , and elastic members 358 .
- the low rotary shaft 351 is secured to the web members 320 by press-fitting or the like.
- the low rotary shaft 351 may be rotatably linked to the web members 320 , this configuration requires change of an oil passage 410 for supply of an oil to the cam body 352 and can cause rigidity deterioration of the housing 30 .
- the opposite ends of the low rotary shaft 351 support the corresponding web members 320 , respectively.
- the low rotary shaft 351 is located below the high rotary shaft 330 inside the housing 30 .
- the cam body 352 is formed around the circumference of the low rotary shaft 351 .
- the cam body 352 serves to support the follow arms 353 and the low lift cams 355 .
- the cam body 352 may be integrally formed with the low rotary shaft 351 or may be separably coupled thereto.
- the cam body 352 may be formed in a ring shape to be inserted and rotatably coupled to the low rotary shaft 351 . With this configuration, when the cam body 352 is rotated, the low rotary shaft 351 is rotated in the same direction and at the same speed as the cam body 352 .
- the cam body 352 may have a variety of shapes. It should be noted that all of the follow arms 353 and the low lift cams 355 may be integrally formed with the low rotary shaft 351 using a mold.
- each of the follow arms 353 formed on the cam body 352 is reciprocatively pivoted in the direction of the swing arm 100 by periodic compression of the high eccentric rod 342 .
- a rotatable follow roller 354 may be provided to the follow arms 353 to minimize friction on contact points between the follow arms 353 and the high eccentric rod 342 .
- the sub-cam unit 350 may include a pair of follow arms 353 facing each other such that the follow roller 354 is rotatably interposed between the follow arms 353 .
- the follow roller 354 may be rotatably mounted inside the follow arms 353 to protrude from upper and lower sides of the follow arms 353 .
- a central axis P 6 of the follow roller 354 rotates along a circular track around a central axis P 4 of the low rotary shaft 351 .
- the low lift cams 355 formed on the cam body 352 serve to periodically compress the corresponding sides of the swing arms 100 at the same time during rotation of the follow arms 353 .
- each of the low lift cams 355 has a low eccentric rod 356 extending from one side thereof. With this configuration, the low lift cams 355 can be eccentrically rotated.
- the low eccentric rod 356 repetitiously compresses the corresponding swing arm 100 , so that the valve 20 opens and closes the combustion chamber 10 while reciprocating in the up-down direction.
- the follow arms 353 and the low lift cams 355 may be integrally formed with the cam body 352 and extend from the cam body 352 in different directions from each other.
- the low eccentric rod 356 of the low lift cam 355 may be located lower than the follow roller 354 of the follow arm 353 on the cam body 352 . This configuration serves to allow the low eccentric rod 356 to compress the one side of the corresponding swing arm 100 while being minimally pivoted when the follow roller 354 is rotated by compression of the high eccentric rod 342 .
- the cam body 352 may have the same number of low lift cams 355 at opposite sides of the follower arms 353 .
- a plurality of low lift cams 355 is formed on the cam body 352 to compress the corresponding swing arms 100 .
- the same number of low lift cams 355 may be formed at the opposite sides of the follower arms 353 to provide at least one pair of low lift cams 355 .
- the cam body 352 has a different number of low lift cams 355 at the opposite sides of the follower arms 353 , slightly different rotational moments can be generated to cause unbalanced behavior of the swing arms 100 .
- the cam body 352 is shown as having a single low lift cam 355 at either side of the follower arms 353 to have a pair of low lift cams 355 .
- the cam body 352 is resiliently supported by the elastic members 358 . This serves to maintain the follow roller 354 and the high lift cam 340 in close contact with each other during operation and to prevent the inertial force of the cam body 352 from being transferred to the swing arms 100 .
- each of the elastic members 358 is coupled to the low rotary shaft 351 to be supported at one side thereof by a link shaft 360 described below and at the other side thereof by the cam body 352 .
- the elastic member 358 may be a torsion spring. It should be understood that the invention is not limited thereto and a variety of mechanical elements may be used as the elastic member 358 as long as they can perform the function of the elastic member in this embodiment.
- a pair of elastic members 358 may be provided to opposite sides of the low rotary shaft 351 to resiliently support the opposite sides of the cam body 352 with the same force.
- each of the elastic members 358 is supported at one side thereof by the link shaft 360 to elastically support the cam body 352 .
- the low lift cam 355 may be formed with a contact surface 357 to support the center of the swing arm 100 .
- the contact surface 357 serves to compress an upper side of the swing arm 100 in order to maintain the swing arm 100 in a state of being supported by the bottom surface of the housing 30 .
- the contact surface 357 may be brought into slight contact with the center of the swing arm 100 or may be slightly separated from the swing arm 100 . This is for the purpose of minimizing friction between the contact surface 357 and the swing arm 100 .
- a swing roller 110 is rotatably mounted on an inner center of the swing arm 100 and exposed upward to directly contact the contact surface 357 .
- the swing roller 110 has a central axis P 5 at the center of the center line L 1 connecting the other side center P 1 with the one side center P 2 of the swing arm 100 .
- the link shaft 360 rotatably connected to the web members 320 is connected to an actuation unit 370 .
- the actuation unit 370 serves to adjust the compression of the low lift cam 355 on the one side of each of the swing arms 100 depending on a slanted degree of the follower arm 353 which varies by movement of the link shaft 360 along an arcuate track about the pivot member 310 .
- the actuation unit 370 includes a connecting rod 371 , a link pin 372 , a screw member 373 , and a power transmission member 374 .
- the connecting rod 371 is connected to the link shaft 360 to directly push the link shaft 360 upon application of an external pushing force of linear reciprocation. Since the link shaft 360 is connected to the connecting rod 371 , it moves along with the connecting rod 371 and is provided to the web members 320 , which are rotatably mounted on the pivot member 310 . As a result, the web members 320 are capable of reciprocating along an arcuate track together with the link shaft 360 about the pivot member 310 .
- the connecting rod 371 may be integrally formed with the link shaft 360 or may be separably mounted on the link shaft 360 . Further, various modifications may be made to the connecting rod 371 .
- link pin 372 is linked to the connecting rod 371
- screw member 373 is linked to the link pin 372 and linearly reciprocates perpendicular to an axis of the link shaft 360 to induce reciprocation of the link shaft 360 on the arcuate track.
- the power transmission member 374 is formed on the circumference of the screw member 373 and reciprocates the screw member 373 in a forward and rearward direction while being forcibly rotated by an external force.
- the screw member 373 may include, but is not limited to, a ball screw as well as a variety of mechanical elements. Further, the power transmission member 374 may be a nut which is capable of being rotated by an external force. The power transmission member 374 is connected to a power generator 374 a such as a motor and the like. The power generator 374 a may be fastened to the power transmission member 374 by a bolt. The power generator 374 a serves to restrict the power transmission member 374 so as not to move in the axial direction of the actuation unit 370 during movement or stoppage of the power transmission member 374 .
- FIGS. 5 to 8 are operational diagrams of the valve driving apparatus in accordance with the embodiment of the invention.
- the actuation unit 370 is operated such that the imaginary line L 2 connecting the central axis P 5 of the swing roller 110 to the central axis P 4 of the low rotary shaft 351 is perpendicular to the center line L 1 connecting the other side center P 1 of the swing arm 100 to the one side center P 2 thereof, in a state wherein the swing arm 100 is not compressed by the low lift cam 355 , so that the swing arm 100 is not pivoted and the valve 20 closes the combustion chamber 10 .
- the contact surface 357 of the low lift cam 355 is in slight contact with the swing roller 110 to thereby support the upper side of the swing arm 100 in the downward direction.
- the high lift cam 340 contacts the follow roller 354 between the follow arms 353 , with the high eccentric rod 342 of the high lift cam 340 directed opposite the follow roller 354 .
- FIG. 6 shows that the high rotary shaft 330 is rotated by an external force in a state wherein the power transmission member 374 is stopped and the imaginary line L 2 is perpendicular to the center line L 1 connecting the other side center P 1 of the swing arm 100 to the one side center P 2 thereof.
- the high lift cam 340 When the high rotary shaft 330 is rotated by the external force, the high lift cam 340 is rotated together with the high rotary shaft 330 , so that the high eccentric rod 342 compresses the follow roller 354 of the follow arm 353 for a predetermined duration.
- the valve 20 opens (or closes) the combustion chamber 10 .
- the valve 20 when the follow roller 354 is compressed by a portion of the high eccentric rod 342 corresponding to an end of the longest axis (r) from the central axis P 3 of the high rotary shaft 330 , the valve 20 is completely lowered to a predetermined distance D 1 , thereby maximally opening the combustion chamber 10 within a preset range.
- the valve 20 opens (or closes) the combustion chamber 10 by a pushing force of the swing arm 100 .
- the power transmission member 374 is rotated to allow the connecting rod 371 and the web member 320 to rotate along an arcuate track about the pivot member 310 .
- FIG. 7 shows that the imaginary line L 2 is slanted to the center line L 1 in a state wherein the swing arm 100 is not compressed by the low lift cam 355 so that the swing arm 100 is not pivoted and the valve 20 closes the combustion chamber 10 .
- the central axis P 6 of the follow roller 354 is moved the same distance as the predetermined distance “A”, by which the web member 320 and the low rotary shaft 351 are moved along the arcuate track in the counterclockwise direction, so that the follow arm 353 is lifted a predetermined height in the counterclockwise direction about the central axis P 4 of the low rotary shaft 351 .
- the contact surface 357 of the low lift cam 355 is in slight contact with the swing roller 110 to thereby support the upper side of the swing arm 100 in the downward direction.
- the swig roller 110 has a diameter so as to continue to contact the contact surface 357 moving along the arcuate track in an initial closed state of the valve 20 .
- the high lift cam 340 contacts the follow roller 354 of the follow arm 353 , with the high eccentric rod 342 directed opposite the follow roller 354 .
- FIG. 8 shows that the high rotary shaft 330 is rotated by an external force in a state wherein the power transmission member 374 is stopped and the imaginary line L 2 is slanted to the center line L 1 .
- the high lift cam 340 When the high rotary shaft 330 is rotated by the external force, the high lift cam 340 is rotated together with the high rotary shaft 330 , so that the high eccentric rod 342 compresses the follow roller 354 of the follow arm 354 for a predetermined duration.
- the low lift cam 355 is rotated in the same direction as the cam body 352 as soon as the cam body 352 is rotated. Then, the low eccentric rod 356 compresses one side of the corresponding swing arm 100 . As a result, the valve 20 opens (or closes) the combustion chamber 10 .
- the valve 20 is completely lowered to a predetermined distance D 2 , thereby maximally opening the combustion chamber 10 within a preset range.
- the valve 20 opens (or closes) the combustion chamber 10 by a pushing force of the swing arm 100 .
- the lowered distance D 2 of the valve 20 with the center line L 1 slanted to the imaginary line L 2 is longer than the lowered distance D 1 of the valve 20 with the center line L 1 perpendicular to the imaginary line L 2 .
- This is attributed to the fact that, as the follow roller 354 is lifted a predetermined height with respect to the central axis P 4 of the low rotary shaft 351 while being moved by the predetermined distance D 1 along the arcuate track, the valve 20 is subjected to a greater pushing amount of the high eccentric rod 342 than in the other case.
- FIG. 9 is a perspective view of a valve driving apparatus including a drive unit in accordance with another embodiment of the present invention.
- a drive unit 370 of the valve driving apparatus includes an actuator 375 and a screw member 378 .
- the actuator 375 has a receiving groove 376 which receives a link shaft 360 therein.
- the receiving groove 376 may have an elongated shape in the up-down direction or may have a hole shape which is open toward a lower side of the actuator 375 .
- a plurality of actuators 375 may be formed on the link shaft 360 to actuate simultaneously, but only a single actuator 375 is shown as being connected to the link shaft 360 for convenience of description in this embodiment. Various modifications may be made to the actuator 375 .
- a screw member 378 is axially inserted into the actuator 375 in a perpendicular direction to an axial direction of the link shaft 360 .
- the actuator 375 is linearly reciprocated forward and rearward in the axial direction of the screw member 378 .
- the screw member 378 may be a ball screw.
- the structure wherein the screw member 378 is rotated by an external force and the structure wherein the screw member 378 is rotatably positioned may be realized in various ways.
- FIG. 10 shows oil passages 410 formed to minimize friction between respective components of the valve driving apparatus when a lubricant is supplied to the respective components through the housing 30 .
- the housing 30 is formed at one side thereof with an inlet 420 through which the housing 30 receives a lubricant.
- the housing 30 has an oil passage 410 defined from the inlet 420 to a portion thereof on which the support member 200 is mounted.
- the support member 200 can continue to support a lower surface of the other side of the swing arm 100 by a pushing force of the lubricant supplied through the oil passage 410 .
- the housing 30 is formed with another oil passage 410 from the inlet 420 to the pivot member. Then, the pivot member 310 guides the lubricant into the web members 320 , which in turn guide the lubricant into the low rotary shaft 351 . Then, the lubricant is supplied from the low rotary shaft 351 to the cam body 352 and is then discharged through an outlet 430 formed in the cam body 352 to flow towards contact portions between the high lift cam 340 and the follow rollers 354 .
- the oil passage 410 is defined in the pivot member 310 , the web members 320 , the low rotary shaft 351 , and the cam body 352 .
- oil passage 410 may be formed along various paths so as to flow to various contact portions between all of the components.
- the valve driving apparatus is capable of precisely adjusting lift amounts of valves periodically opening and closing the combustion chamber through adjustment of a rolling contact area and a cam separation of a double-cam unit cooperatively connected thereto, thereby realizing optimum fuel economy and output.
- a high rotary shaft having an upper side cam of the double-cam unit mounted thereon is not directly connected to a low rotary shaft having a lower side cam of the double-cam unit, thereby allowing the separation between the cams of the double-cam unit to be easily adjusted.
- a pair of web members connected to opposite ends of the low rotary shaft is simultaneously pivoted in the same direction and at the same speed to allow the low rotary shaft to move along an arcuate track while maintaining its axial direction, so that a plurality of valves can be controlled to have the same lift amount.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Valve Device For Special Equipments (AREA)
Abstract
Disclosed herein is a valve driving apparatus. The valve driving apparatus includes at least one swing arm having one side corresponding to an upper side of a valve opening and closing a combustion chamber of an internal combustion engine; and a cam unit periodically pivoting the swing arm. Here, the swing arm performs a swing motion on the other side thereof by external manipulation to periodically compress the valve. The valve driving apparatus is capable of adjusting lift amounts of valves opening and closing a combustion chamber of an internal combustion engine.
Description
- This application claims the benefit under 35 U.S.C. §119 of Korean Patent Application No. 10-2008-0113562, filed Nov. 14, 2008, which is hereby incorporated by reference in its entirety.
- 1. Field of the Invention
- The present invention relates to a valve driving apparatus and, more particularly, to a valve driving apparatus that is capable of continuously adjusting lift amounts of valves opening and closing a combustion chamber of an internal combustion engine with a double-cam unit to provide optimum fuel economy and output.
- 2. Description of the Related Art
- In general, an internal combustion engine of vehicles includes a combustion chamber in which fuel is burned to generate power. The combustion chamber is provided with a valve train, which includes intake/exhaust valves controlling the flow of intake and exhaust gases and is associated with a crankshaft to open and close the combustion chamber.
- In a typical valve train, the valve is open in a constant lift amount by a cam having a predetermined configuration, so that the amount of intake or exhaust gas is restricted to a constant amount. Thus, with a design contemplated for low speed driving conditions, time and degree of valve opening are insufficient in high-speed drive conditions, and with a design contemplated for the high speed drive conditions, a reverse phenomenon occurs in the low speed drive conditions.
- More specifically, since a general internal combustion engine tuned for high speed driving is set to have a high valve lift value, it exhibits good performance under high-speed conditions, but is very disadvantageous in terms of idle stability and low-speed torque characteristics under low speed conditions. On the contrary, the engine tuned for low speed driving provides good idle stability and low-speed torque under low-speed conditions but exhibits limited performance under high-speed conditions. However, a variable valve lift technique varies the lift amount of the valve corresponding to the high-speed and low-speed conditions, thereby providing merits both under low-speed and high-speed conditions.
- Accordingly, it has been attempted in recent years to develop a technique for increasing a charging efficiency in addition to a multi-valve technique to enhance fuel economy and output. As a result, various techniques have been developed, for example a variable induction system (VIS), a variable valve timing (VVT) technique, and a variable valve lift (VVL) technique. The variable induction system changes a length or cross-sectional area of an intake manifold in accordance with suction resistance of air that varies in accordance with an engine speed. In the variable valve timing technique and the variable valve lift technique, the time and degree of opening the valve are adjusted in accordance with an engine speed to control overlap timing, thereby controlling the cylinder charging amount and the remaining gas amount.
- In a conventional variable valve lift-type valve driving apparatus, however, since the lift amount of the valve cannot be varied and time of opening or closing the intake or exhaust valve is fixed in a constant state, the amount of intake or exhaust air cannot be adjusted, so that optimum fuel economy and output cannot be obtained corresponding to an engine operation state. Therefore, there is a need to provide a valve driving apparatus that overcomes such problems.
- The present invention is conceived to solve the above problems of the related art, and an aspect of the invention is to provide a valve driving apparatus that is capable of precisely adjusting lift amounts of valves periodically opening and closing a combustion chamber of an internal combustion engine with a double-cam unit associated therewith in order to achieve optimum fuel economy and output.
- According to an aspect of the invention, a valve driving apparatus includes: at least one swing arm having one side corresponding to an upper side of a valve opening and closing a combustion chamber of an internal combustion engine; and a cam unit periodically pivoting the swing arm. Here, the swing arm performs a swing motion on the other side thereof by external manipulation to periodically compress the valve.
- The cam unit may include: a pivot member acting as a reference axis of the cam unit; a web member formed on the pivot member; a high rotary shaft forcibly rotated by an external force; a high lift cam formed on the high rotary shaft and including a high eccentric rod eccentrically rotated during rotation of the high rotary shaft; and a sub-cam unit connected to the web member and simultaneously operating one or more swing arms through the high eccentric rod during rotation of the high lift cam.
- The sub-cam unit may include: a low rotary shaft rotatably connected to the web member; a cam body formed on the low rotary shaft; a follow arm formed on the cam body to be rotated in a direction of the swing arm by periodic compression of the high eccentric rod; a low lift cam formed on the low rotary shaft and including a low eccentric rod to periodically compress one side of each of the swing arms at the same time during rotation of the follow arm; and an elastic member elastically supporting the cam body.
- The cam body may include the same number of low lift cams at opposite sides of the follow arm. The follow arm may be provided with a rotatable follow roller at a portion thereof where the follower arm directly contacts the high lift cam. The low lift cam may include a contact surface formed to support a center of each of the swing arm. The swing arm may include a rotatable swing roller disposed at a portion thereof contacting the contact surface.
- The follow arm and the low lift cam may be extended from the cam body in different directions from each other.
- The web member may be rotatably connected to the link shaft, and the link shaft may be connected to an actuation unit.
- The actuation unit may include: a connecting rod connected to the link shaft; a link pin linked to the connecting rod; a screw member linked to the link pin and linearly reciprocating in a perpendicular direction to an axis of the link shaft to reciprocate the link shaft on the arcuate track; and a power transmission member formed around a circumference of the screw member and reciprocating the screw member in a forward and rearward direction when the power transmission member is forcibly rotated by an external force.
- The actuation unit may include: an actuator having a receiving groove that receives the link shaft therein; and a screw member screwed to the actuator and linearly reciprocating the actuator in a forward and rearward direction to guide reciprocation of the link shaft on an arcuate track when the screw member is forcibly rotated by an external force.
- The elastic member may be supported at one side thereof by the link shaft and at the other side thereof by the cam body. The sub-cam unit may be received in a housing, and the sub-cam unit and the housing may include oil passages connected to each other between the sub-cam unit and the housing to receive a lubricant from outside through the oil passages.
- The above and other aspects, features and advantages of the invention will become apparent from the following detailed description given in conjunction with the accompanying drawings, in which:
-
FIG. 1 is a side section view of a valve driving apparatus mounted in a housing in accordance with one embodiment of the present invention; -
FIGS. 2 and 3 are perspective views of connection between components of the valve driving apparatus in accordance with the embodiment of the present invention; -
FIG. 4 is an exploded perspective view of the valve driving apparatus in accordance with the embodiment of the present invention; -
FIGS. 5 to 8 are operational diagrams of the valve driving apparatus in accordance with the embodiment of the present invention; -
FIG. 9 is a perspective view of a valve driving apparatus in accordance with another embodiment of the present invention; and -
FIG. 10 shows oil passages formed in a valve driving apparatus in accordance with one embodiment of the present invention. - Embodiments of the invention will now be described in detail with reference to the accompanying drawings. It should be noted that the drawings are not to precise scale and may be exaggerated in thickness of lines or sizes of components for descriptive convenience and clarity only. Furthermore, the terms as used herein are defined by taking functions of the invention into account and can be changed according to the custom or intention of users or operators. Therefore, definition of the terms should be made according to the overall disclosures set forth herein.
- Referring to
FIGS. 1 to 4 , a valve driving apparatus according to one embodiment of the invention includesswing arms 100 and acam unit 300, which can variably control lift amounts ofvalves 20 opening and closing acombustion chamber 10 in an internal combustion engine. - Each of the
swing arms 100 has one side corresponding to an upper side of thevalve 20, which opens and closes thecombustion chamber 10, and performs a swing motion on the other side thereof by external manipulation to directly compress thevalve 20 in a periodic manner. Theswing arm 100 generates a constant profile of oscillation to allow thevalve 20 to reciprocate in an up-down direction in a constant period. Accordingly, as theswing arm 100 rotates about the other side thereof to allow the one side thereof to periodically compress an upper side of thevalve 20, thevalve 20 can be open or closed, that is, reciprocate in the up-down direction. - Here, the
swing arm 100 is provided at the one side thereof with thevalve 20 to face a lower surface of the one side in the longitudinal direction of theswing arm 100, and at the other side thereof with astationary support member 200 to face a lower surface of the other side thereof. Thus, the other side of theswing arm 100 is supported by asupport member 200 such that theswing arm 100 can rotate about the other side thereof. - As such, the lower surface of the one side of the
swing arm 100 comes into contact with thevalve 20 and the lower surface of the other side of theswing arm 100 is in contact with thesupport member 200, so that thesupport member 200 continues to exert an upward force to the lower surface of the other side of theswing arm 100. Accordingly, theswing arm 100 is capable of rotating about the other side center P1 supported by thesupport member 200. In other words, an imaginary center line L1 connecting the other side center P1 with one side center P2 of theswing arm 100 is reciprocatively pivoted about the other side center P1 in a predetermined range of pivot angles. - Here, the
support member 200 is securely mounted on ahousing 30. A common structure may be used to mount thesupport member 200 on thehousing 30. In addition, since theswing arm 100 is supportively connected to thesupport member 200 and thevalve 20, theswing arm 100 is not easily vibrated or displaced. Here, thehousing 30 is formed at an upper side of thecombustion chamber 10. Various modifications may be made to theswing arm 100 and thesupport member 200. - As described above, the
swing arm 100 is rotated about the other side thereof by an external force. Here, thecam unit 300 serves to periodically pivot theswing arm 100. Thecam unit 300 includes apivot member 310,web members 320, a highrotary shaft 330, ahigh lift cam 340, and asub-cam unit 350. - The
pivot member 310 acts as a reference axis of thecam unit 300. Thus, thepivot member 310 is secured inside thehousing 30. Here, asingle pivot member 310 may be provided to one inner side of thehousing 30, but twopivot members 310 may be provided to opposite inner sides of thehousing 30 to firmly support theweb members 320, respectively. In this case, each of theweb members 320 is rotatably connected to thecorresponding pivot member 310. In other words, each of thepivot members 310 is rotatably fitted into thecorresponding web member 320, which is rotated about thepivot member 310. It should be understood that, with thepivot members 310 rotatably inserted into thehousing 30, theweb members 320 may be integrally formed with thepivot members 310. In this embodiment, thepivot member 310 is shown as having a shaft shape, but various modifications may be made to thepivot member 310. - As such, the
web member 320 is connected to thecorresponding pivot member 310. In other words, thepivot member 310 is rotatably inserted into a lower side of theweb member 320. Thus, theweb member 320 can be rotated about thepivot member 310. It should be understood that with theweb members 320 integrally formed with thecorresponding pivot members 310 to rotate together, thepivot members 310 may be rotatably mounted on thehousing 30. In this embodiment, theweb member 320 is shown as having a plate shape, but various modifications may be made to theweb member 320. - The high
rotary shaft 330 is forcibly rotated by an external force. Particularly, the highrotary shaft 330 is supported by thehousing 30. That is, opposite ends of the highrotary shaft 330 are rotatably supported on the opposite sides of thehousing 30, respectively. With this configuration, the highrotary shaft 330 can be firmly supported. - The high
rotary shaft 330 is provided with thehigh lift cam 340. Thehigh lift cam 340 has a higheccentric rod 342 extending from one side thereof. With this configuration, thehigh lift cam 340 eccentrically rotates. In other words, at any time when thehigh lift cam 340 is rotated about its rotational axis P3 to position the higheccentric rod 342 extending from one side thereof at a predetermined location on the circumference thereof, the higheccentric rod 342 compresses theswing arms 100 and followarms 353 of thecam unit 300 described below, so that thevalves 20 opens and closes thecombustion chamber 10 while reciprocating in the up-down direction. - Here, the
high lift cam 340 rotates in the same direction and at the same speed as those of the highrotary shaft 330. Thehigh lift cam 340 may be separably coupled to the highrotary shaft 330 or may be integrally formed therewith by molding. The separable coupling of thehigh lift cam 340 to the highrotary shaft 330 may be achieved by bolts and the like, particularly, by diffusion bonding. - On the other hand, the
sub-cam unit 350 is connected to theweb members 320. Thesub-cam unit 350 serves to simultaneously operate one ormore swing arms 100 in cooperation with the higheccentric rod 342 during rotation of thehigh lift cam 340. - The
sub-cam unit 350 includes a lowrotary shaft 351, acam body 352, thefollow arms 353,low lift cams 355, andelastic members 358. - The low
rotary shaft 351 is secured to theweb members 320 by press-fitting or the like. Here, although the lowrotary shaft 351 may be rotatably linked to theweb members 320, this configuration requires change of anoil passage 410 for supply of an oil to thecam body 352 and can cause rigidity deterioration of thehousing 30. - Here, since a pair of
web members 320 is provided to thecam unit 300 in this embodiment, the opposite ends of the lowrotary shaft 351 support thecorresponding web members 320, respectively. The lowrotary shaft 351 is located below the highrotary shaft 330 inside thehousing 30. - The
cam body 352 is formed around the circumference of the lowrotary shaft 351. Thecam body 352 serves to support thefollow arms 353 and thelow lift cams 355. Here, thecam body 352 may be integrally formed with the lowrotary shaft 351 or may be separably coupled thereto. Particularly, thecam body 352 may be formed in a ring shape to be inserted and rotatably coupled to the lowrotary shaft 351. With this configuration, when thecam body 352 is rotated, the lowrotary shaft 351 is rotated in the same direction and at the same speed as thecam body 352. Thecam body 352 may have a variety of shapes. It should be noted that all of thefollow arms 353 and thelow lift cams 355 may be integrally formed with the lowrotary shaft 351 using a mold. - Each of the
follow arms 353 formed on thecam body 352 is reciprocatively pivoted in the direction of theswing arm 100 by periodic compression of the higheccentric rod 342. Here, arotatable follow roller 354 may be provided to the followarms 353 to minimize friction on contact points between thefollow arms 353 and the higheccentric rod 342. Here, thesub-cam unit 350 may include a pair of followarms 353 facing each other such that thefollow roller 354 is rotatably interposed between thefollow arms 353. It should be noted that thefollow roller 354 may be rotatably mounted inside thefollow arms 353 to protrude from upper and lower sides of thefollow arms 353. Additionally, a central axis P6 of thefollow roller 354 rotates along a circular track around a central axis P4 of the lowrotary shaft 351. - The
low lift cams 355 formed on thecam body 352 serve to periodically compress the corresponding sides of theswing arms 100 at the same time during rotation of thefollow arms 353. At this time, each of thelow lift cams 355 has a loweccentric rod 356 extending from one side thereof. With this configuration, thelow lift cams 355 can be eccentrically rotated. - In other words, at any time when each of the
low lift cams 355 is rotated about its rotational axis P4 to position the loweccentric rod 356 extending from one side thereof at a predetermined location on the circumference thereof, the loweccentric rod 356 repetitiously compresses thecorresponding swing arm 100, so that thevalve 20 opens and closes thecombustion chamber 10 while reciprocating in the up-down direction. - The follow
arms 353 and thelow lift cams 355 may be integrally formed with thecam body 352 and extend from thecam body 352 in different directions from each other. Particularly, the loweccentric rod 356 of thelow lift cam 355 may be located lower than thefollow roller 354 of thefollow arm 353 on thecam body 352. This configuration serves to allow the loweccentric rod 356 to compress the one side of thecorresponding swing arm 100 while being minimally pivoted when thefollow roller 354 is rotated by compression of the higheccentric rod 342. - The
cam body 352 may have the same number oflow lift cams 355 at opposite sides of thefollower arms 353. In other words, a plurality oflow lift cams 355 is formed on thecam body 352 to compress thecorresponding swing arms 100. At this time, the same number oflow lift cams 355 may be formed at the opposite sides of thefollower arms 353 to provide at least one pair oflow lift cams 355. If thecam body 352 has a different number oflow lift cams 355 at the opposite sides of thefollower arms 353, slightly different rotational moments can be generated to cause unbalanced behavior of theswing arms 100. For descriptive convenience, thecam body 352 is shown as having a singlelow lift cam 355 at either side of thefollower arms 353 to have a pair oflow lift cams 355. - On the other hand, the
cam body 352 is resiliently supported by theelastic members 358. This serves to maintain thefollow roller 354 and thehigh lift cam 340 in close contact with each other during operation and to prevent the inertial force of thecam body 352 from being transferred to theswing arms 100. - If the
high lift cam 340 is separated from thefollow roller 354 during operation, various problems such as noise and valve jumping can occur. Noise generation can cause fatigue failure resulting from repetitious impact and the higher the speed with which such a phenomenon occurs, the greater the inertial force of thecam body 352. As a result, as soon as thehigh lift cam 340 of the highrotary shaft 330 pushes thefollow roller 354 of thelow lift shaft 351, a degree of opening thevalve 20 is increased over a desired degree by the inertial force of thecam body 352. Accordingly, it is desirable that theelastic members 358 firmly support thecam body 352. - More specifically, each of the
elastic members 358 is coupled to the lowrotary shaft 351 to be supported at one side thereof by alink shaft 360 described below and at the other side thereof by thecam body 352. It should be understood that the opposite sides of theelastic member 358 may be supported at different positions. In this embodiment, theelastic member 358 may be a torsion spring. It should be understood that the invention is not limited thereto and a variety of mechanical elements may be used as theelastic member 358 as long as they can perform the function of the elastic member in this embodiment. Further, a pair ofelastic members 358 may be provided to opposite sides of the lowrotary shaft 351 to resiliently support the opposite sides of thecam body 352 with the same force. - With this configuration, each of the
elastic members 358 is supported at one side thereof by thelink shaft 360 to elastically support thecam body 352. - The
low lift cam 355 may be formed with acontact surface 357 to support the center of theswing arm 100. Thecontact surface 357 serves to compress an upper side of theswing arm 100 in order to maintain theswing arm 100 in a state of being supported by the bottom surface of thehousing 30. When the loweccentric rod 356 of thelow lift cam 355 compresses the one side of theswing arm 100, thecontact surface 357 may be brought into slight contact with the center of theswing arm 100 or may be slightly separated from theswing arm 100. This is for the purpose of minimizing friction between thecontact surface 357 and theswing arm 100. Here, aswing roller 110 is rotatably mounted on an inner center of theswing arm 100 and exposed upward to directly contact thecontact surface 357. Theswing roller 110 has a central axis P5 at the center of the center line L1 connecting the other side center P1 with the one side center P2 of theswing arm 100. - On the other hand, the
link shaft 360 rotatably connected to theweb members 320 is connected to anactuation unit 370. Theactuation unit 370 serves to adjust the compression of thelow lift cam 355 on the one side of each of theswing arms 100 depending on a slanted degree of thefollower arm 353 which varies by movement of thelink shaft 360 along an arcuate track about thepivot member 310. - For example, the
actuation unit 370 includes a connectingrod 371, alink pin 372, ascrew member 373, and apower transmission member 374. - The connecting
rod 371 is connected to thelink shaft 360 to directly push thelink shaft 360 upon application of an external pushing force of linear reciprocation. Since thelink shaft 360 is connected to the connectingrod 371, it moves along with the connectingrod 371 and is provided to theweb members 320, which are rotatably mounted on thepivot member 310. As a result, theweb members 320 are capable of reciprocating along an arcuate track together with thelink shaft 360 about thepivot member 310. The connectingrod 371 may be integrally formed with thelink shaft 360 or may be separably mounted on thelink shaft 360. Further, various modifications may be made to the connectingrod 371. - Additionally, the
link pin 372 is linked to the connectingrod 371, and thescrew member 373 is linked to thelink pin 372 and linearly reciprocates perpendicular to an axis of thelink shaft 360 to induce reciprocation of thelink shaft 360 on the arcuate track. Thepower transmission member 374 is formed on the circumference of thescrew member 373 and reciprocates thescrew member 373 in a forward and rearward direction while being forcibly rotated by an external force. - Namely, when the
power transmission member 374 is rotated by the external force, thescrew member 373 is linearly moved forward and rearward by a rotational force of thepower transmission member 374 and the connectingrod 371 is reciprocated by the external force in the forward and rearward direction from thelink pin 372 to thereby control thelink shaft 360 to reciprocate along the arcuate track. - The
screw member 373 may include, but is not limited to, a ball screw as well as a variety of mechanical elements. Further, thepower transmission member 374 may be a nut which is capable of being rotated by an external force. Thepower transmission member 374 is connected to apower generator 374 a such as a motor and the like. Thepower generator 374 a may be fastened to thepower transmission member 374 by a bolt. Thepower generator 374 a serves to restrict thepower transmission member 374 so as not to move in the axial direction of theactuation unit 370 during movement or stoppage of thepower transmission member 374. -
FIGS. 5 to 8 are operational diagrams of the valve driving apparatus in accordance with the embodiment of the invention. - Referring to
FIG. 5 , theactuation unit 370 is operated such that the imaginary line L2 connecting the central axis P5 of theswing roller 110 to the central axis P4 of the lowrotary shaft 351 is perpendicular to the center line L1 connecting the other side center P1 of theswing arm 100 to the one side center P2 thereof, in a state wherein theswing arm 100 is not compressed by thelow lift cam 355, so that theswing arm 100 is not pivoted and thevalve 20 closes thecombustion chamber 10. - The
contact surface 357 of thelow lift cam 355 is in slight contact with theswing roller 110 to thereby support the upper side of theswing arm 100 in the downward direction. - In addition, the
high lift cam 340 contacts thefollow roller 354 between thefollow arms 353, with the higheccentric rod 342 of thehigh lift cam 340 directed opposite thefollow roller 354. - Descriptions of other components are the same as those described in the above embodiment and will be omitted herein.
-
FIG. 6 shows that the highrotary shaft 330 is rotated by an external force in a state wherein thepower transmission member 374 is stopped and the imaginary line L2 is perpendicular to the center line L1 connecting the other side center P1 of theswing arm 100 to the one side center P2 thereof. - When the high
rotary shaft 330 is rotated by the external force, thehigh lift cam 340 is rotated together with the highrotary shaft 330, so that the higheccentric rod 342 compresses thefollow roller 354 of thefollow arm 353 for a predetermined duration. - When the high
eccentric rod 342 compresses thefollow roller 354, thelow lift cam 355 is rotated in the same direction as thecam body 352 as soon as thecam body 352 is rotated. Then, the loweccentric rod 356 compresses one side of thecorresponding swing arm 100. Accordingly, thevalve 20 opens (or closes) thecombustion chamber 10. - Particularly, when the
follow roller 354 is compressed by a portion of the higheccentric rod 342 corresponding to an end of the longest axis (r) from the central axis P3 of the highrotary shaft 330, thevalve 20 is completely lowered to a predetermined distance D1, thereby maximally opening thecombustion chamber 10 within a preset range. Here, as the higheccentric rod 342 continues to compress thefollow roller 354 in a predetermined round section, thevalve 20 opens (or closes) thecombustion chamber 10 by a pushing force of theswing arm 100. - Descriptions of other components are the same as those described in the above embodiment and will be omitted herein.
- In
FIG. 7 , thepower transmission member 374 is rotated to allow the connectingrod 371 and theweb member 320 to rotate along an arcuate track about thepivot member 310. - In other words,
FIG. 7 shows that the imaginary line L2 is slanted to the center line L1 in a state wherein theswing arm 100 is not compressed by thelow lift cam 355 so that theswing arm 100 is not pivoted and thevalve 20 closes thecombustion chamber 10. - When the
screw member 373 is linearly retracted, theweb member 320 and the lowrotary shaft 351 are moved a predetermined distance “A” along an arcuate track in the counterclockwise direction. - Here, the central axis P6 of the
follow roller 354 is moved the same distance as the predetermined distance “A”, by which theweb member 320 and the lowrotary shaft 351 are moved along the arcuate track in the counterclockwise direction, so that thefollow arm 353 is lifted a predetermined height in the counterclockwise direction about the central axis P4 of the lowrotary shaft 351. - The
contact surface 357 of thelow lift cam 355 is in slight contact with theswing roller 110 to thereby support the upper side of theswing arm 100 in the downward direction. Thus, preferably, theswig roller 110 has a diameter so as to continue to contact thecontact surface 357 moving along the arcuate track in an initial closed state of thevalve 20. - In addition, the
high lift cam 340 contacts thefollow roller 354 of thefollow arm 353, with the higheccentric rod 342 directed opposite thefollow roller 354. - Descriptions of other components are the same as those described in the above embodiment and will be omitted herein.
-
FIG. 8 shows that the highrotary shaft 330 is rotated by an external force in a state wherein thepower transmission member 374 is stopped and the imaginary line L2 is slanted to the center line L1. - When the high
rotary shaft 330 is rotated by the external force, thehigh lift cam 340 is rotated together with the highrotary shaft 330, so that the higheccentric rod 342 compresses thefollow roller 354 of thefollow arm 354 for a predetermined duration. - When the high
eccentric rod 342 compresses thefollow roller 354, thelow lift cam 355 is rotated in the same direction as thecam body 352 as soon as thecam body 352 is rotated. Then, the loweccentric rod 356 compresses one side of thecorresponding swing arm 100. As a result, thevalve 20 opens (or closes) thecombustion chamber 10. - Then, when the
follow roller 354 is compressed by a portion of the higheccentric rod 342 corresponding to the end of the longest axis (r) from the central axis P3 of the highrotary shaft 330, thevalve 20 is completely lowered to a predetermined distance D2, thereby maximally opening thecombustion chamber 10 within a preset range. Here, when the higheccentric rod 342 continues to compress thefollow roller 354 in a predetermined round section, thevalve 20 opens (or closes) thecombustion chamber 10 by a pushing force of theswing arm 100. - The lowered distance D2 of the
valve 20 with the center line L1 slanted to the imaginary line L2 is longer than the lowered distance D1 of thevalve 20 with the center line L1 perpendicular to the imaginary line L2. This is attributed to the fact that, as thefollow roller 354 is lifted a predetermined height with respect to the central axis P4 of the lowrotary shaft 351 while being moved by the predetermined distance D1 along the arcuate track, thevalve 20 is subjected to a greater pushing amount of the higheccentric rod 342 than in the other case. - Descriptions of other components are the same as those described in the above embodiment and will be omitted herein.
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FIG. 9 is a perspective view of a valve driving apparatus including a drive unit in accordance with another embodiment of the present invention. - In this embodiment, a
drive unit 370 of the valve driving apparatus includes anactuator 375 and ascrew member 378. - The
actuator 375 has a receivinggroove 376 which receives alink shaft 360 therein. Here, since thelink shaft 360 is moved along an arcuate track, the receivinggroove 376 may have an elongated shape in the up-down direction or may have a hole shape which is open toward a lower side of theactuator 375. - Here, a plurality of
actuators 375 may be formed on thelink shaft 360 to actuate simultaneously, but only asingle actuator 375 is shown as being connected to thelink shaft 360 for convenience of description in this embodiment. Various modifications may be made to theactuator 375. - A
screw member 378 is axially inserted into theactuator 375 in a perpendicular direction to an axial direction of thelink shaft 360. Thus, when thescrew member 378 is rotated by an external force, theactuator 375 is linearly reciprocated forward and rearward in the axial direction of thescrew member 378. Thescrew member 378 may be a ball screw. The structure wherein thescrew member 378 is rotated by an external force and the structure wherein thescrew member 378 is rotatably positioned may be realized in various ways. - When the
actuator 375 is linearly reciprocated in the forward and rearward direction, thelink shaft 360 andweb members 320 are reciprocated along an arcuate track about apivot member 310. - The principle in variation of the lowered distance of the valves according to forward and rearward movement of the
actuator 375 is the same as in the above embodiment. - Descriptions of other components are the same as those described in the above embodiment and will be omitted herein.
-
FIG. 10 showsoil passages 410 formed to minimize friction between respective components of the valve driving apparatus when a lubricant is supplied to the respective components through thehousing 30. - The
housing 30 is formed at one side thereof with aninlet 420 through which thehousing 30 receives a lubricant. Thehousing 30 has anoil passage 410 defined from theinlet 420 to a portion thereof on which thesupport member 200 is mounted. Thesupport member 200 can continue to support a lower surface of the other side of theswing arm 100 by a pushing force of the lubricant supplied through theoil passage 410. - The
housing 30 is formed with anotheroil passage 410 from theinlet 420 to the pivot member. Then, thepivot member 310 guides the lubricant into theweb members 320, which in turn guide the lubricant into the lowrotary shaft 351. Then, the lubricant is supplied from the lowrotary shaft 351 to thecam body 352 and is then discharged through anoutlet 430 formed in thecam body 352 to flow towards contact portions between thehigh lift cam 340 and thefollow rollers 354. Thus, theoil passage 410 is defined in thepivot member 310, theweb members 320, the lowrotary shaft 351, and thecam body 352. - It should be understood that the
oil passage 410 may be formed along various paths so as to flow to various contact portions between all of the components. - As apparent from the above description, according to one embodiment of the invention, the valve driving apparatus is capable of precisely adjusting lift amounts of valves periodically opening and closing the combustion chamber through adjustment of a rolling contact area and a cam separation of a double-cam unit cooperatively connected thereto, thereby realizing optimum fuel economy and output. Further, according to another embodiment of the invention, a high rotary shaft having an upper side cam of the double-cam unit mounted thereon is not directly connected to a low rotary shaft having a lower side cam of the double-cam unit, thereby allowing the separation between the cams of the double-cam unit to be easily adjusted. Moreover, according to a further embodiment of the invention, a pair of web members connected to opposite ends of the low rotary shaft is simultaneously pivoted in the same direction and at the same speed to allow the low rotary shaft to move along an arcuate track while maintaining its axial direction, so that a plurality of valves can be controlled to have the same lift amount.
- In understanding the scope of the invention, the use of articles “a,” “an” and “the” in the context of describing the invention, especially in the context of the embodiments, are to be construed to cover both the singular and the plural, unless otherwise indicated or clearly contradicted by context.
- Although some embodiments have been provided to illustrate the invention in conjunction with the drawings, it will be apparent to those skilled in the art that the embodiments are given by way of illustration only, and that various modifications, changes, substitutions, and equivalent embodiments can be made without departing from the spirit and scope of the invention. The scope of the invention should be limited only by the accompanying claims.
Claims (13)
1. A valve driving apparatus, comprising:
at least one swing arm having one side corresponding to an upper side of a valve opening and closing a combustion chamber of an internal combustion engine, the swing atm performing a swing motion on the other side thereof by external manipulation to periodically compress the valve; and
a cam unit periodically pivoting the swing aim.
2. The valve driving apparatus according to claim 1 , wherein the cam unit comprises:
a pivot member acting as a reference axis of the cam unit;
a web member formed on the pivot member;
a high rotary shaft forcibly rotated by an external force;
a high lift cam formed on the high rotary shaft and including a high eccentric rod eccentrically rotated during rotation of the high rotary shaft; and
a sub-cam unit connected to the web member and simultaneously operating the at least one swing arm through the high eccentric rod during rotation of the high lift cam.
3. The valve driving apparatus according to claim 2 , wherein the sub-cam unit comprises:
a low rotary shaft rotatably connected to the web member;
a cam body formed on the low rotary shaft;
a follow arm formed on the cam body to be rotated in a direction of the swing arm by periodic compression of the high eccentric rod;
a low lift cam formed on the low rotary shaft and including a low eccentric rod to periodically compress one side of the corresponding swing arm at the same time during rotation of the follow arm; and
an elastic member elastically supporting the cam body.
4. The valve driving apparatus according to claim 3 , wherein the cam body comprises the same number of low lift cams at opposite sides of the follow arm.
5. The valve driving apparatus according to claim 3 , wherein the follow arm is provided with a rotatable follow roller at a portion thereof where the follower arm directly contacts the high lift cam.
6. The valve driving apparatus according to claim 3 , wherein the low lift cam comprises a contact surface formed to support a center of the swing arm.
7. The valve driving apparatus according to claim 6 , wherein the swing arm comprises a rotatable swing roller disposed at a portion thereof contacting the contact surface.
8. The valve driving apparatus according to claim 3 , wherein the follow arm and the low lift cam are extended from the cam body in different directions from each other.
9. The valve driving apparatus according to any one of claims 2 to 8 , wherein the web member is rotatably connected to the link shaft, and the link shaft is connected to an actuation unit, the actuation unit adjusting a compression amount of the low lift cam on the one side of the swing arm depending on a slanted degree of the follow arm that varies according to movement of the link shaft along an arcuate track about the pivot member.
10. The valve driving apparatus according to claim 9 , wherein the actuation unit comprises:
a connecting rod connected to the link shaft;
a link pin linked to the connecting rod;
a screw member linked to the link pin and linearly reciprocating in a perpendicular direction to an axis of the link shaft to reciprocate the link shaft on the arcuate track; and
a power transmission member formed around a circumference of the screw member and reciprocating the screw member in a forward and rearward direction when the power transmission member is forcibly rotated by an external force.
11. The valve driving apparatus according to claim 9 , wherein the actuation unit comprises:
an actuator having a receiving groove that receives the link shaft therein; and
a screw member screwed to the actuator and linearly reciprocating the actuator in a forward and rearward direction to guide reciprocation of the link shaft on an arcuate track when the screw member is forcibly rotated by an external force.
12. The valve driving apparatus according to claim 9 , wherein the elastic member is supported at one side thereof by the link shaft and at the other side thereof by the cam body.
13. The valve driving apparatus according to claim 9 , wherein the sub-cam unit is received in a housing, and wherein the sub-cam unit and the housing comprise oil passages connected to each other between the sub-cam unit and the housing to receive a lubricant from outside through the oil passages.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR1020080113562A KR101143305B1 (en) | 2008-11-14 | 2008-11-14 | Apparatus for driving engine valve |
KR10-2008-0113562 | 2008-11-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
US20100122678A1 true US20100122678A1 (en) | 2010-05-20 |
Family
ID=42171005
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/617,756 Abandoned US20100122678A1 (en) | 2008-11-14 | 2009-11-13 | Valve driving apparatus |
Country Status (3)
Country | Link |
---|---|
US (1) | US20100122678A1 (en) |
KR (1) | KR101143305B1 (en) |
CN (1) | CN101737114A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110100311A1 (en) * | 2008-06-16 | 2011-05-05 | Chery Automobile Co., Ltd | Variable valve lift system for an internal combustion engine |
US20120145102A1 (en) * | 2008-10-07 | 2012-06-14 | Riley Michael B | Varying The Phase And Lift Of A Rocker Arm On A Camshaft Actuating A Valve Or Injector |
CN103216291A (en) * | 2013-04-28 | 2013-07-24 | 长城汽车股份有限公司 | Air valve lifting device for engine, engine comprising same, and automobile comprising same |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN102979589B (en) * | 2011-09-06 | 2015-05-20 | 北汽福田汽车股份有限公司 | Valve timing mechanism for engine, engine and automobile |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7305946B2 (en) * | 2004-11-30 | 2007-12-11 | Hitachi, Ltd. | Variable valve operating apparatus for internal combustion engine |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3966149B2 (en) * | 2002-10-10 | 2007-08-29 | 三菱自動車工業株式会社 | Continuously variable valve operating device for internal combustion engine |
JP2006152926A (en) | 2004-11-30 | 2006-06-15 | Hitachi Ltd | Variable valve gear in internal combustion engine |
JP2008014191A (en) * | 2006-07-04 | 2008-01-24 | Toyota Motor Corp | Variable valve device |
KR100868209B1 (en) * | 2006-11-16 | 2008-11-11 | 현대자동차주식회사 | Continuous variable valve lift apparatus |
-
2008
- 2008-11-14 KR KR1020080113562A patent/KR101143305B1/en active IP Right Grant
-
2009
- 2009-11-13 US US12/617,756 patent/US20100122678A1/en not_active Abandoned
- 2009-11-13 CN CN200910222917A patent/CN101737114A/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7305946B2 (en) * | 2004-11-30 | 2007-12-11 | Hitachi, Ltd. | Variable valve operating apparatus for internal combustion engine |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110100311A1 (en) * | 2008-06-16 | 2011-05-05 | Chery Automobile Co., Ltd | Variable valve lift system for an internal combustion engine |
US8701608B2 (en) * | 2008-06-16 | 2014-04-22 | Chery Automobile Co., Ltd | Variable valve lift system for an internal combustion engine |
US20120145102A1 (en) * | 2008-10-07 | 2012-06-14 | Riley Michael B | Varying The Phase And Lift Of A Rocker Arm On A Camshaft Actuating A Valve Or Injector |
US20120174885A1 (en) * | 2008-10-07 | 2012-07-12 | Riley Michael B | Varying The Phase And Lift Of A Rocker Arm On A Camshaft Actuating A Valve Or Injector |
US8534244B2 (en) * | 2008-10-07 | 2013-09-17 | Yelir, Inc. | Varying the phase and lift of a rocker arm on a camshaft actuating a valve or injector |
US8544431B2 (en) * | 2008-10-07 | 2013-10-01 | Yelir, Inc. | Varying the phase and lift of a rocker arm on a camshaft actuating a valve or injector |
CN103216291A (en) * | 2013-04-28 | 2013-07-24 | 长城汽车股份有限公司 | Air valve lifting device for engine, engine comprising same, and automobile comprising same |
Also Published As
Publication number | Publication date |
---|---|
CN101737114A (en) | 2010-06-16 |
KR20100054585A (en) | 2010-05-25 |
KR101143305B1 (en) | 2013-12-06 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: GARGASO ENGINEERING CO., LTD.,KOREA, REPUBLIC OF Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:KIM, HYUNG GI;REEL/FRAME:023513/0810 Effective date: 20091112 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |