JP2016094866A - Variable valve device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain an engine valve in a valve-closed state even if a part a cam lobe member located in a storage position protrudes to the outside of a radial direction from a cam base member.SOLUTION: A lift variable mechanism 40 comprises a cam lobe member 44 which can oscillate between a storage position and a protrusion position with respect to a cam base member 43, and a lock mechanism which switches a lock state of the cam lobe member at the protrusion position. An intervention mechanism 70 comprises an input member 72, an output member 73, a first portion 81 and a second portion 82 which are arranged at a cam surface 77 of the output member, and a change mechanism which changes a relative position of the input member and the output member. When an engine valve 25 is maintained at a valve-closed state, a control part releases the lock of the cam lobe member from the protrusion position, and controls the lock mechanism and the change mechanism so as to make a roker arm 24 abut on the first portion but not abut on the second portion at the abutment of a protruded part 83 of the cam lobe member in the storage position on the input member.SELECTED DRAWING: Figure 16

Description

  The present invention relates to a variable valve operating apparatus for an internal combustion engine.

  An intermediary mechanism that is interposed between a camshaft and a rocker arm and transmits a driving force from the camshaft to the rocker arm is known (see, for example, Patent Document 1). The intermediary mechanism includes a swingable first arm that is in contact with the cam of the camshaft, a swingable second arm that is in contact with the rocker arm, and a pinch between the first arm and the second arm. And a change mechanism for changing the corner. By changing the sandwiching angle by the changing mechanism, the lift amount and the operating angle of the engine valve composed of the intake valve or the exhaust valve are continuously variable.

JP 2006-112324 A International Publication No. 2014/030226

  Among such mediation mechanisms, there is a mechanism that cannot maintain the engine valve in a closed state (that is, cannot be brought into a resting state) for reasons such as mounting on an internal combustion engine, unlike the one in Patent Document 1. Then, when it is requested to do so, it is not possible to meet the request, which is disadvantageous.

  In order to meet this demand, it is conceivable to combine a variable lift mechanism as disclosed in Patent Document 2 in place of the normal camshaft with the mediation mechanism. The lift variable mechanism includes a cam base member that is rotationally driven by a driving force from a crankshaft, and a cam lobe member that is swingably connected to the cam base member. The cam lobe member is stored in the cam base member. The lift amount of the engine valve is made variable by selectively positioning it at any one of the protruding positions protruding radially outward from the cam base member.

  However, when such a combination is assumed, the cam lobe member may have to be larger than a general size in order to obtain a maximum lift amount equivalent to that obtained when an ordinary camshaft is combined with the mediation mechanism.

  However, in this case, when the cam lobe member is positioned at the retracted position, the cam lobe member may not be completely stored in the cam base member, and a part of the cam lobe member may protrude radially outward from the cam base member. Then, even if the cam lobe member is positioned at the retracted position, the protruding portion of the cam lobe member may lift the engine valve via the mediation mechanism and the rocker arm. As a result, it is difficult to keep the engine valve closed.

  Therefore, an object of the present invention is to provide a variable motion of an internal combustion engine that can maintain an engine valve in a closed state even when a part of a cam lobe member in a retracted position protrudes radially outward from the cam base member. It is to provide a valve device.

According to one aspect of the invention,
A variable lift mechanism for making the lift amount of the engine valve composed of an intake valve or an exhaust valve variable between a non-lift state and a lift state;
An intermediary mechanism interposed between the lift variable mechanism and the rocker arm, and for making the lift amount of the engine valve variable from a low lift side to a high lift side;
A controller configured to control the variable lift mechanism and the mediation mechanism;
With
The lift variable mechanism is
A cam base member that is rotationally driven by a driving force from the crankshaft;
A cam lobe member that is swingably connected to the cam base member, and is stored in the cam base member and corresponds to the no-lift state, and protrudes radially outward from the cam base member to correspond to the lifted state. A cam lobe member swingable between the protruding position and
A lock mechanism for switching the lock state of the cam lobe member at the protruding position;
With
The mediation mechanism is:
An input member in contact with at least one of the cam base member and the cam lobe member;
An output member having a cam surface in contact with the rocker arm;
A first portion that is provided on the cam surface and does not cause movement in the lift direction of the rocker arm;
A second portion that is provided on the cam surface and that causes the rocker arm to move in the lift direction;
A change mechanism for changing the relative positions of the input member and the output member;
With
The cam lobe member has a protruding portion that protrudes radially outward from the cam base member in the retracted position;
The control unit controls the lock mechanism to unlock the cam lobe member from the protruding position when the engine valve is maintained in a closed state, and the protruding portion of the cam lobe member in the retracted position is the input member. A variable valve operating apparatus for an internal combustion engine is provided, wherein the change mechanism is controlled so that the rocker arm abuts against the first part and does not abut against the second part.

  According to the present invention, even when a part of the cam lobe member in the retracted position protrudes radially outward from the cam base member, an excellent effect is exhibited that the engine valve can be maintained in the closed state. The

It is a schematic front view of the variable valve operating apparatus according to the present embodiment. It is a whole perspective view of a mediation mechanism. It is the whole lift variable mechanism perspective view. It is a vertical front view of a variable lift mechanism, and shows a state when the cam lobe member is in the protruding position. It is a vertical front view of a variable lift mechanism, and shows a state when the cam lobe member is in the retracted position. It is sectional drawing for demonstrating the action | operation of a lift variable mechanism. It is sectional drawing for demonstrating the action | operation of a lift variable mechanism. It is sectional drawing for demonstrating the action | operation of a lift variable mechanism. It is sectional drawing for demonstrating the action | operation of a lift variable mechanism. It is sectional drawing for demonstrating the action | operation of a lift variable mechanism. It is sectional drawing for demonstrating the action | operation of a lift variable mechanism. It is an enlarged front view of a mediation mechanism. It is a schematic front view of a variable valve apparatus. It is a graph which shows the operating characteristic of a mediation mechanism. It is a schematic front view of a variable valve apparatus. It is a schematic front view of a variable valve apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  Although not shown in the drawings, the variable valve operating apparatus according to the present embodiment is provided to make variable the operating characteristics of intake valves or exhaust valves (generally referred to as “engine valves”) of an internal combustion engine (engine). Yes. The “operation characteristic” includes at least one of lift amount, operating angle, and valve timing (open and close timing). In particular, the variable valve operating apparatus according to the present embodiment performs either one of all cylinder operation for operating all cylinders or reduced cylinder operation for operating some of the cylinders and operating the remaining cylinders. The present invention is applied to a constructed multi-cylinder internal combustion engine. Such an internal combustion engine capable of reducing cylinder operation is well known. Hereinafter, for the sake of convenience, some of the cylinders will be referred to as “restorable cylinders”, and the remaining cylinders will be referred to as “always operating cylinders”. The present embodiment is applied to a cylinder capable of resting, and is configured to maintain the engine valve of the cylinder capable of resting during the reduced-cylinder operation (that is, always closed). The engine valve may be either an intake valve or an exhaust valve. The present embodiment is applied to an engine valve that is desired to maintain a closed state.

  In the present embodiment described below, an example in which the present invention is applied to an intake valve of a cylinder capable of rest is shown as an example. Two intake valves are provided per cylinder, and these two intake valves are operated equally by the variable valve operating apparatus according to the present embodiment. The restable cylinder is composed of a plurality of cylinders, and the same configuration is made for each cylinder. Unless otherwise specified, the configuration described later is a configuration per cylinder. The same operation is performed in each cylinder of the cylinders that can be deactivated. The internal combustion engine is a V-type 6-cylinder gasoline engine for vehicles, and 3 cylinders belonging to one of the banks constitute cylinders that can be deactivated. However, the internal combustion engine to which the present invention is applied is arbitrary, and the use or purpose of use of the present invention is not limited to maintaining the closed state during reduced-cylinder operation.

  As shown in FIG. 1, the variable valve operating apparatus according to the present embodiment includes a variable lift mechanism 40 for changing the lift amount of the intake valve 25 between a non-lift state and a lift state, and a variable lift mechanism 40. And an intermediate mechanism for transmitting the driving force from the variable lift mechanism 40 to the rocker arm 24 and making the lift amount of the intake valve 25 variable from the low lift side to the high lift side. 70, and an electronic control unit (hereinafter referred to as “ECU”) 100 (see FIGS. 2 and 6) as a control unit configured to control the lift variable mechanism 40 and the mediation mechanism 70. In particular, in this embodiment, a variable lift mechanism 40 is provided in place of a normal camshaft to which a cam is fixed. In the figure, 26 is a valve spring, and 27 is a hydraulic lash adjuster. A rocker arm 24, a valve spring 26 and a hydraulic lash adjuster 27 are provided for each intake valve 25. The ECU 100 also controls the entire engine.

  Here, the “no lift state” means a state in which the intake valve 25 is not lifted, and the “with lift state” means a state in which the intake valve 25 is lifted. However, strictly speaking, when a protruding portion described later acts, there is no strict lift state. Therefore, the “no lift state” means a state where the intake valve 25 is not lifted basically or substantially.

  The mediation mechanism 70 will be described with reference to FIG. In addition, since the mediation mechanism 70 of this embodiment is known, only the principal part relevant to this embodiment is demonstrated here, and detailed description is abbreviate | omitted. In the illustrated example, for the sake of convenience, it should be noted that a normal camshaft 41 ′ is used instead of the variable lift mechanism 40, and that the details of the intermediate mechanism 70 are slightly different from those shown in FIG. .

  The intermediary mechanism 70 includes a hollow support shaft 71 fixed on the cylinder head side, a first arm 72 provided on the support shaft 71 so as to be able to turn or swing, and a support shaft 71 capable of turning or swinging. And second arms 73 and 74 that are provided and come into contact with the rocker arm 24. The direction of the central axis Z of the support shaft 71 is simply referred to as the axial direction. One end side in the axial direction is front and is represented by a symbol Fr, and the other end side is rear and is represented by a symbol Rr.

  Two second arms 73 and 74 are provided corresponding to two intake valves 25 (only one is shown), and are provided adjacent to both sides of the first arm 72 in the axial direction. The first arm 72 and the second arms 73 and 74 are relatively rotatable around the support shaft 71. These arms 72 to 74 are provided for each cylinder capable of rest. A spring 85 as an urging member is disposed in a compressed state between the cylinder head side and the first arm 72, and applies a urging force in the rotational direction to the first arm 72, so that a roller at the tip of the first arm 72 is provided. 75 is always pressed against the cam 41A ′ of the camshaft 41 ′. In addition, the installation method of the spring 85 is arbitrary. For example, the spring 85 may be installed between the support shaft 71 and the first arm 72.

  A nose portion 76 ′ having a substantially triangular shape as viewed from the axial direction is formed to project from the distal ends of the second arms 73 and 74. The nose portion 76 ′ has a cam surface 77 ′ that comes into contact with the rocker arm 24.

  Further, the mediation mechanism 70 sets the relative position between the first arm 72 and the second arms 73 and 74, more specifically, the sandwich angle α between the first arm 72 and the second arms 73 and 74 around the support shaft 71. A change mechanism 78 for changing is provided. The change mechanism 78 includes a control shaft 79 that is slidably inserted in the support shaft 71 and an actuator 80 for causing the control shaft 79 to move in the axial direction. The actuator 80 is controlled by the ECU 100. Note that the support shaft 71 and the control shaft 79 are common to each restable cylinder, and extend across all the restable cylinders. The changing mechanism 78 is fitted on the outer peripheral surface of the support shaft 71 so as to be slidable in the axial direction, and is arranged in the respective internal spaces of the first and second arms 72, 73, 74. including. These slider gears 72G, 73G, and 74G are integrated.

  The slider gear 72 </ b> G is formed of a helical spline formed in a right-handed spiral shape, and meshes with a helical spline formed on the inner peripheral surface of the first arm 72. The slider gears 73 </ b> G and 74 </ b> G are helical splines formed in a left-handed spiral shape, and mesh with the helical splines formed on the inner peripheral surfaces of the second arms 73 and 74.

  The slider gears 72G, 73G, and 74G are connected to the control shaft 79 via pins and the like, and in conjunction with the axial movement of the control shaft 79 with respect to the support shaft 71, the first and second arms 72, 73, and 74 are connected. Within each internal space, it can move in the axial direction with respect to the support shaft 71. On the other hand, the axial movement of the first and second arms 72, 73, 74 relative to the support shaft 71 is restricted by a thrust member (not shown).

  Therefore, the axial movement of the control shaft 79, that is, the axial movement of the slider gears 72G, 73G, and 74G is a direction in which the first arm 72 and the second arm 73 and 74 are moved toward and away from each other around the support shaft 71. In other words, the sandwiching angle α between the first arm 72 and the second arms 73 and 74 around the support shaft 71 is reduced or enlarged. Here, the sandwiching angle α is an angle between the angular position of the first arm 72 and the angular positions of the second arms 73 and 74 when viewed from the axial direction (see FIG. 1). It can be said that the sandwiching angle α is a value representing an angular relative position between the first arm 72 and the second arms 73 and 74 around the axis.

  As the sandwiching angle α is increased or decreased, the angular position of the first arm 72 around the support shaft 71 and the angular positions of the second arms 73 and 74 are also changed. This is because the spring 85 rotates the first arm 72 around the support shaft 71 so as to press the roller 75 of the first arm 72 against the cam 41 </ b> A ′. Accordingly, as a result, the relative position of the first arm 72 and the second arms 73 and 74 around the support shaft 71 is changed by the axial movement of the control shaft 79.

  By such movement of the control shaft 79 in the axial direction, the lift amount of the intake valve 25, in particular, in the case of this embodiment, the lift amount and the operating angle are continuously variable. That is, when the control shaft 79 is moved in the − direction shown in the figure by the actuator 80, the sandwiching angle α is reduced, and the lift amount and the operating angle of the intake valve 25 are reduced. On the contrary, when the control shaft 79 is moved in the + direction shown in the figure by the actuator 80, the sandwiching angle α is enlarged, and the lift amount and the operating angle of the intake valve 25 are increased. The lift amount and the working angle are decreased and increased in conjunction with each other.

  The intermediate mechanism 70 is similar to the above-described variable lift mechanism 40 in that the lift amount is variable, but the intermediate mechanism 70 is lifted in that the lift amount is continuously variable from the low lift side to the high lift side. Note that it is different from the variable mechanism 40.

  Thus, the first arm 72 corresponds to the “input member” according to the present invention, the second arms 73 and 74 correspond to the “output member” according to the present invention, and the change mechanism 78 refers to the “change” according to the present invention. Corresponds to "mechanism".

  Next, the variable lift mechanism 40 will be described with reference to FIGS. Here, as shown in FIG. 1, the case of the present embodiment in which the lift variable mechanism 40 is combined with the mediation mechanism 70 will be described.

  As shown in FIGS. 3 and 4, the variable lift mechanism 40 includes a drive shaft 41 and a cam unit 42 that is coaxially connected to the drive shaft 41. The cam unit 42 is provided for each cylinder that can be deactivated. The drive shaft 41 is divided at the position of each restable cylinder, and each cam unit 42 is coaxially connected to the divided portion. However, the attachment method of the cam unit 42 with respect to the drive shaft 41 is arbitrary. In this way, the variable lift mechanism 40 as a whole extends in the cylinder row direction, that is, in the crankshaft axial direction so as to reach all the restable cylinders.

  The drive shaft 41 and the cam unit 42 have a common central axis X. Here, for convenience, the direction of the central axis X is simply referred to as the axial direction. The central axis X is parallel to the central axis Z of the support shaft 71.

  The drive shaft 41 is rotatably supported on the cylinder head by a bearing (not shown). The drive shaft 41 is connected to the crankshaft at a front end portion thereof via a power transmission mechanism such as a belt / pulley mechanism. Therefore, both the drive shaft 41 and the cam unit 42 are rotationally driven by the drive force from the crankshaft. The rotation direction of the drive shaft 41 and the cam unit 42 is indicated by R in the figure. A known variable valve timing mechanism may be provided between the drive shaft 41 and the power transmission mechanism.

  The cam unit 42 includes a cam base member 43 that forms a main body thereof, and two cam lobe members 44 that are swingably or pivotably connected to the front side and the rear side of the cam base member 43, respectively. The two cam lobe members 44 correspond to the two intake valves 25.

  The cam base member 43 is formed in a substantially cylindrical shape having a larger diameter than the drive shaft 41, and has a circular base circle portion 45 when viewed from the axial direction. The base circle portion 45 constitutes the outer peripheral surface of the cam base member 43, and corresponds to a base circle portion of a normal camshaft cam. The base circle 45 has a constant radius around the central axis X. Two base circular portions 45 are also provided corresponding to the two intake valves 25. A slit 46 is provided in each base circle 45, and a cam lobe member 44 is inserted into each slit 46. The cam lobe member 44 has a substantially U-shape as shown in FIG.

  In the cam base member 43, a recess 47 is formed between the two base circles 45. A support shaft 48 is provided so as to penetrate the cam base member 43 in the axial direction. The support shaft 48 is inserted into the shaft hole 49 of the base end portion 44 </ b> B of the cam lobe member 44. Thereby, the cam lobe member 44 can turn or swing around the support shaft 48.

  The cam lobe member 44 protrudes maximally outward from the cam base member 43 in the radial direction (shown in FIG. 4), and is stored in the cam base member 43 maximally without protruding from the cam base member 43 (see FIG. 4). 5). The protruding position corresponds to the lifted state, and the retracted position corresponds to the non-lifted state. The two cam lobe members 44 are respectively provided with stopper pins 50 protruding in the axial direction, and these stopper pins 50 are slidably inserted into the long holes 51 provided in the cam base member 43. The movement of the stopper pin 50 is restricted by the long hole 51, and as a result, the swing range, the protruding position, and the retracted position of the cam lobe member 44 are defined. As will be described in detail later, the cam lobe member 44 is locked at either the protruding position or the retracted position.

  In FIG. 3, for convenience, the cam lobe member 44 located in the axially forward Fr is in the retracted position and the cam lobe member 44 located in the axially rearward Rr is in the protruding position, but both cam lobe members 44 are actually the same. Located in position.

  The recess 47 is provided with two springs 52 and 52 for urging the two cam lobe members 44 toward the protruding positions. These springs 52 and 52 form another urging member. The spring 52 is a coil spring and is wound around the outside of the support shaft 33. A base end portion of the spring 52 is fixed to the cam base member 43 via a fixed shaft 53. The tip end of the spring 52 is engaged with the stopper pin 50, and the stopper pin 50 and thus the cam lobe member 44 are urged toward the protruding position.

  As schematically shown in FIG. 6, the roller 75 of the first arm 72 of the mediation mechanism 70 is brought into contact with at least one of the cam lobe member 44 and the portion of the base circle 45 adjacent to the front and rear thereof. That is, as shown in FIG. 4, when the cam lobe member 44 is in the protruding position, the roller 75 is in contact with the cam lobe member 44 in the angular region around the axis where the cam lobe member 44 protrudes from the base circle 45, In the angle region, the roller 75 is brought into contact with the base circle 45. As shown in FIG. 5, when the cam lobe member 44 is in the retracted position, the roller 75 basically comes into contact with only the cam lobe member 44. However, when the outer peripheral surface 44A of the cam lobe member 44 is on the same plane as the base circle 45 when the cam lobe member 44 is in the retracted position (also referred to as the retracted position), the roller 75 is the cam lobe member. 44 and the base circle 45. Further, as will be described later, when a part of the cam lobe member 44 protrudes radially outward from the base circle 45 even when the cam lobe member 44 is in the retracted position, the roller 75 has a cam lobe at the protruding portion. It abuts on the member 44.

  Thus, when the cam lobe member 44 is in the protruding position, the cam unit 42 drives the first arm 72 of the mediation mechanism 70 in the direction in which the intake valve 25 is lifted (opened) (referred to as “lift direction”). The arm 72 and the second arms 73 and 74 are swung. On the other hand, when the cam lobe member 44 is in the retracted position, the cam unit 42 basically does not apply a driving force for lifting the intake valve 25 to the first arm 72. The lift variable mechanism 40 makes the lift amount and operating angle of the intake valve 25 basically variable in two stages, zero and a larger value.

  In addition, the variable lift mechanism 40 is a lock mechanism 60 for switching the lock state of the cam lobe member 44 at the projecting position, specifically, a lock mechanism for locking the cam lobe member 44 at either the projecting position or the storage position. 60. Hereinafter, the configuration of the lock mechanism 60 and the operation of the variable lift mechanism 40 will be described with reference to FIGS. 6-11 schematically show the VI-VI cross section of FIG. 4 in each state.

  FIG. 6 shows a state where the cam lobe member 44 as shown in FIG. 4 is in the protruding position. Here, as can be understood from the above description and related drawings, the cam unit 42 is configured to be symmetrical in the longitudinal direction in the axial direction. Accordingly, only the configuration on the front side will be described here. It will be understood that this description applies to the rear configuration as well.

  A supply path 61 extending coaxially with the central axis X is provided inside the drive shaft 41 and the cam base member 43. In the cam base member 43, paths 62 and 63 extending radially outward from the supply path 61 at different angular positions around the central axis X are formed. The paths 62 and 63 extend radially outward and then turn in the axial direction toward the slit 46.

Inside the cam base member 43, a pin hole 64H communicating with the path 62 and a pin hole 65H coaxial with the pin hole 64H and having the same diameter are provided. The pin hole 65H is located at a position facing the pin hole 64H across the slit 46. A pin hole 66H having the same diameter as that of the pin hole 64H is also provided at the distal end portion 44C of the cam lobe member 44. Pins 64P, 65P, 66P having the same diameter are slidably inserted into the pin holes 64H, 65H, 66H, respectively. The pin hole 65H is provided with a spring 65S for urging the pin 65P toward the slit 46 side.
The other path 63 is open to the slit 46. A pin hole 67 </ b> H is provided inside the cam base member 43, and the pin hole 67 </ b> H is in a coaxial position facing the slit 46 from the open end of the path 63. A pin 67P is slidably inserted into the pin hole 67H, and a compressible spring 67S that holds the pin 67P in the pin hole 67H is disposed. The pin hole 67H has the same diameter as the above-described pin holes 64H, 65H, and 66H, and the pin 67P has the same diameter as the above-described pins 64P, 65P, and 66P.

  By changing the engagement state of these pins 64P, 65P, 66P, 67P and the pin holes 64H, 65H, 66H, 67H, the cam lobe member 44 can be locked at the protruding position or the retracted position.

  Oil or hydraulic pressure is supplied to the supply path 61 from an oil pump 69 via an oil control valve (OCV) 68. The oil control valve 68 is an electromagnetically driven flow control valve and is controlled by the ECU 100. The oil pump 69 is a mechanical type driven by a crankshaft and supplies oil stored in an oil pan. However, the configuration for supplying oil to the supply path 61 may be other configurations, for example, the oil pump 69 may be electrically operated.

  FIG. 6 shows a state when the cam lobe member 44 is locked at the protruding position as shown in FIG. At this time, no oil is supplied to the supply path 61 (the hydraulic pressure is off), and the pin holes 66H of the cam lobe member 44 are aligned coaxially with the pin holes 64H and 65H of the cam base member 43 as shown in FIG. Has been. Due to the biasing force of the spring 65S, the pin 65P is commonly inserted in a state straddling the pin holes 65H and 66H, and the pin 66P is also commonly inserted in a state straddling the pin holes 66H and 64H. Thereby, the cam lobe member 44 is locked to the cam base member 43 at the protruding position. The pin 64P is completely inserted into the pin hole 64H.

  From this state, the operation when the cam lobe member 44 is moved to the storage position and locked to the storage position is as follows. First, as shown in FIG. 7, the oil control valve 68 is opened, and oil is supplied to the supply path 61 (hydraulic-on state). Then, due to the hydraulic pressure supplied from the path 62, the adjacent pins 64P, 65P, 66P are pushed forward against the urging force of the spring 65S, and the pins 65P, 66P engage with the pin holes 64H, 65H, 66H. Come off. That is, the three pins 64P, 65P, 66P are arranged only in the corresponding pin holes 64H, 65H, 66H, respectively. As a result, the cam lobe member 44 is unlocked from the protruding position, and the cam lobe member 44 can move toward the retracted position.

  When the cam base member 43 rotates and the cam lobe member 44 rides on the roller 75 in this state, the cam lobe member 44 is pushed by the roller 75 (specifically, due to the valve spring reaction force) and gradually moves to the retracted position. During this movement, the cam lobe member 44 carries the pin 66P while holding the pin 66P in its own pin hole 66H.

  FIG. 8 shows a state at the moment when the cam lobe member 44 reaches the storage position. At this time, the pin hole 66H of the tip end portion 44C of the cam lobe member 44 is aligned with the pin hole 67H of the cam base member 43.

  Since the hydraulic pressure is still on, when the cam lobe member 44 reaches the retracted position, the pins 66P and 67P compress the spring 67S by the hydraulic pressure from the other path 63 as shown in FIG. While being pushed forward, the pin 66P is inserted in common in a state straddling the pin holes 67H and 66H. Thereby, as shown also in FIG. 5, the cam lobe member 44 is locked to the cam base member 43 in the retracted position. The pin 67P is completely inserted into the pin hole 67H. In order to keep the cam lobe member 44 locked in the retracted position, it is necessary to maintain the hydraulic pressure on.

  Next, the operation when the cam lobe member 44 is moved from the retracted position to the protruding position and locked to the protruding position will be described.

  First, the hydraulic pressure is turned off from the state shown in FIG. That is, the oil control valve 68 is closed, the supply of oil to the supply path 61 is stopped, and the oil is discharged from the supply path 61. Then, as shown in FIG. 10, the pins 66P and 67P are pushed backward by the spring 67S, and the engagement of the pin 66P with the pin hole 67H is released. That is, the two pins 66P and 67P are arranged only in the corresponding pin holes 66H and 67H, respectively. As a result, the cam lobe member 44 is unlocked from the retracted position, and the cam lobe member 44 can move toward the protruding position.

  When the cam base member 43 rotates in this state, the cam lobe member 44 comes off the roller 75, and the base circle 45 of the cam base member 43 rides on the roller 75, the cam lobe member 44 gradually moves to the protruding position by the biasing force of the spring 52. To do. During this movement, the cam lobe member 44 carries the pin 66P while holding the pin 66P in its own pin hole 66H.

  FIG. 11 shows a state at the moment when the cam lobe member 44 reaches the protruding position. At this time, the pin hole 66H of the cam lobe member 44 is aligned with the pin holes 64H and 65H of the cam base member 43.

  Then, as shown in FIG. 6, the pins 64P, 65P, 66P are pushed backward by the urging force of the spring 65S, and the pin 65P is inserted in a state straddling the pin holes 65H, 66H. It is inserted in common in the state straddling the holes 66H and 64H. Thereby, the cam lobe member 44 is locked at the protruding position. As long as the hydraulic pressure is off, the cam lobe member 44 is kept locked in the protruding position.

  In summary, the cam lobe member 44 is locked at the protruding position when the hydraulic pressure is off, and locked at the retracted position when the hydraulic pressure is on.

  Returning to FIG. 1, the mediation mechanism 70 of the present embodiment is different from that shown in FIG. 2 in the shape of the second arms 73 and 74, particularly the shape of the nose portion 76 provided at the distal end portion thereof. Here, since the shapes of the two second arms 73 and 74 are the same, only one of the second arms 73 will be described.

  As shown in the enlarged view of FIG. 12, the second arm 73 has a base end 73 </ b> A attached to the support shaft 71 so as to be swingable. The outer peripheral surface 73B of the base end portion 73A has a cylindrical shape and has a constant radius around the central axis Z of the support shaft 71, that is, the oscillation central axis of the second arm 73. On the other hand, the second arm 73 has a nose portion 76 that protrudes radially outward from the base end portion 73A. The nose portion 76 forms a tip portion of the second arm 73 and has a substantially triangular shape or a beak shape when viewed from the axial direction as illustrated.

  A cam surface 77 that contacts the rocker arm 24 is formed by the outer peripheral surface 73B and the lower surface of the nose portion 76, that is, the surface facing the rocker arm 24 side. The cam surface 77 is formed by the outer peripheral surface 73 </ b> B and has a base circle portion 81 having a constant radius around the central axis Z, and is continuously adjacent to the base circle portion 81 and protrudes radially outward with respect to the base circle portion 81. And a lift part 82. The angle regions of the base circle portion 81 and the lift portion 82 are denoted by β1 and β2, respectively. The lift part 82 is formed so as to protrude outward in the radial direction as the distance from the base circle part 81 increases, or to increase the radius.

  As shown in FIG. 1, when the base circle portion 81 is in contact with the rocker arm 24, the rocker arm 24 does not move in the lift direction (that is, the rocker arm 24 does not move in the lift direction), and therefore the intake air The lift (opening) of the valve 25 does not occur. On the other hand, as shown in FIG. 13, when the lift portion 82 is in contact with the rocker arm 24, the operation of the rocker arm 24 in the lift direction occurs (that is, the rocker arm 24 moves in the lift direction). 25 lifts occur.

  Thus, the cam surface 77 corresponds to the “cam surface” according to the present invention, the base circle portion 81 corresponds to the “first portion” according to the present invention, and the lift portion 82 corresponds to the “second portion” according to the present invention. Is equivalent to.

  Now, the mediation mechanism 70 of the present embodiment has a structure in which the intake valve 25 cannot be maintained in a closed state (that is, cannot be in a rest state) by a combination with a normal camshaft 41 ′ as shown in FIG. 2. Then, when it is required to do so, particularly in the present embodiment, when it is desired to maintain the intake valve 25 of the idle cylinder during the reduced cylinder operation, the request cannot be met.

  In FIG. 14, the solid line a indicates the operating characteristics of the mediation mechanism 70 when combined with the normal camshaft 41 '. The vertical axis represents the lift amount L of the intake valve 25. The actuator stroke K on the horizontal axis corresponds to the amount of movement of the control shaft 79. As the actuator stroke K increases toward the + side, the movement amount of the control shaft 79 increases toward the + side, and the lift amount L increases. The actuator stroke K can vary from a minimum value Kmin = 0 corresponding to the minimum lift amount Lmin to a maximum value Kmax corresponding to the maximum lift amount Lmax. The intermediate mechanism 70 can continuously change the lift amount L (and the working angle) as shown in the figure, but in actual use, for example, three stages corresponding to the actuator strokes K1, K2, and K3, respectively. The lift amount L is changed to the lift amounts L1, L2, and L3 (K1 <K2 <K3, L1 <L2 <L3). These lift amounts L1, L2, and L3 correspond to predetermined small lift amount (first lift amount), medium lift amount (second lift amount), and large lift amount (third lift amount), respectively.

  Here, the minimum lift amount Lmin is a value larger than zero, which means that the intake valve 25 is slightly opened and not closed. In order to close the intake valve 25, the minimum lift amount Lmin must be zero. For this purpose, the actuator stroke K must be set to the minus side Kmin 'in accordance with the characteristic indicated by the broken line b, and the actuator stroke K must be enlarged to the minus side by ΔKmin. In other words, the total length of the actuator stroke K must be expanded from Kmin to Kmax to Kmin 'to Kmax. However, at present, such expansion is difficult for reasons such as mountability to the engine.

  Therefore, in order to meet the above request, in this embodiment, the intermediate lift mechanism 70 is combined with the variable lift mechanism 40 in place of the normal camshaft 41 '. In this way, by placing the cam lobe member 44 of the variable lift mechanism 40 in the retracted position, it is possible to prevent a driving force from causing a valve lift from being input from the variable lift mechanism 40, and as a result, This is because it is considered that the valve can be kept closed.

  However, this proved to cause another problem. That is, in order to obtain the maximum lift amount equivalent to the maximum lift amount Lmax when the ordinary camshaft 41 ′ is combined with the mediation mechanism 70, the maximum protrusion amount H1 of the cam lobe member 44 at the protrusion position from the cam base member 43 is obtained. (See FIG. 4) must be relatively large. For this purpose, the cam lobe member 44 must be made larger than a general size for reasons such as securing strength, and this is the case in the present embodiment. For example, the mediation mechanism 70 transmits the stroke of the cam lobe member 44 to the rocker arm 24 through intermediate arms such as the first arm 72 and the second arms 73 and 74. Of course, when the maximum lift amount equal to the maximum lift amount Lmax is obtained, the cam lobe member 44 is positioned at the protruding position.

  However, when this is done, the cam lobe member 44 cannot be completely retracted into the cam base member 43 when the cam lobe member 44 is positioned at the retracted position, and a part of the cam lobe member 44 protrudes radially outward from the cam base member 43. In fact, this is the case in this embodiment. Then, even if the cam lobe member 44 is positioned at the retracted position, the protruding portion of the cam lobe member 44 may lift the intake valve 25 via the mediation mechanism 70 and the rocker arm 24. As a result, it is difficult to keep the intake valve 25 closed.

  FIG. 5 shows the protruding portion 83 of the cam lobe member 44 in the retracted position. The protrusion 83 is formed by a portion of the cam lobe member 44 that protrudes radially outward from the base circle 45. In the present embodiment, the protruding portion 83 is formed at the distal end portion 44 </ b> C of the cam lobe member 44. Ideally, such a protruding portion 83 is not originally present, but is formed due to the unavoidable circumstances as described above. Although the maximum protruding amount H2 of the protruding portion 83 is relatively small and is significantly smaller than the maximum protruding amount H1 of the cam lobe member 44 at the protruding position, there is still a possibility of causing a minute lift of the intake valve 25. Note that there may be a plurality of protruding portions, or they may be formed in different parts. For example, it may be formed at the base end portion 44 </ b> B of the cam lobe member 44.

  Therefore, in the present embodiment, even when a part of the cam lobe member 44 protrudes as described above, the ECU 100 executes the following control to maintain the intake valve 25 in the closed state.

  That is, the ECU 100 controls the lock mechanism 60 (specifically, the oil control valve 68) of the variable lift mechanism 40 so that the cam lobe member 44 is unlocked from the protruding position when the intake valve 25 is kept closed. . Specifically, the lock mechanism 60 is controlled so that the cam lobe member 44 is unlocked from the protruding position and the cam lobe member 44 is locked at the retracted position. In addition, the ECU 100 prevents the rocker arm 24 from contacting the base circle portion 81 and not from the lift portion 82 when the protruding portion 83 of the cam lobe member 44 in the retracted position is in contact with the roller 75 of the first arm 72. The change mechanism 78 (specifically, the actuator 80) of the mediation mechanism 70 is controlled.

  Hereinafter, the control in the present embodiment will be described in detail. For example, when a predetermined condition for performing the reduced cylinder operation is satisfied and the intake valve 25 is maintained in the closed state to perform the reduced cylinder operation, the ECU 100 assumes that the cam lobe member 44 is in the protruding position. The change mechanism 78 of the mediation mechanism 70 is controlled so that the lift amount L (and the operating angle) of the valve 25 becomes a predetermined target amount that is not more than a predetermined upper limit amount. The predetermined upper limit amount is a lift amount that does not cause the intake valve 25 to lift even when the protruding portion 83 (particularly, the maximum protruding position) of the cam lobe member 44 in the retracted position is in contact with the roller 75 of the first arm 72. It is the maximum value. The predetermined upper limit amount can be, for example, a medium lift amount L2 as shown in FIG. Therefore, the predetermined target amount can be, for example, the intermediate lift amount L2, the small lift amount L1, or the minimum lift amount Lmin. In any case, the sandwiching angle α is controlled to a relatively small predetermined value α1. In the illustrated examples of FIGS. 1, 13, 15, and 16, the predetermined target amount is the minimum lift amount Lmin, and the sandwiching angle α is fixed to a predetermined minimum value α1 corresponding to the minimum lift amount Lmin.

  The state when the cam lobe member 44 is locked at the protruding position is as shown in FIGS. FIG. 1 shows a state where the base circle 45 is in contact with the roller 75. At this time, naturally, the intake valve 25 is closed without being lifted.

  FIG. 13 shows a state where the cam lobe member 44 (particularly its maximum protruding position) is in contact with the roller 75. At this time, the intake valve 25 is lifted by the minimum lift amount Lmin.

  Although not shown, when the sandwiching angle α is increased by controlling the actuator 80 of the mediation mechanism 70 from the state shown in FIGS. 1 and 13, the lift amount of the intake valve 25 is increased accordingly. In particular, since the cam lobe member 44 having a large size as described above is used, the maximum lift amount equivalent to the maximum lift amount Lmax can be obtained by increasing the sandwiching angle α to a predetermined maximum value.

  On the other hand, the state when the cam lobe member 44 is locked in the retracted position while the state of the intermediary mechanism 70 is kept the same, that is, the holding angle α is kept at the same value α1, is as shown in FIGS. .

  FIG. 15 shows a state where the base circle 45 is in contact with the roller 75. At this time, as in the case of FIG. 1, the intake valve 25 is closed without being lifted. The rocker arm 24 is in contact with the base circle portion 81 of the cam surface 77 of the second arms 73 and 74, particularly at a position relatively distant from the lift portion 82.

  FIG. 16 shows a state where the protruding portion 83 (particularly, the maximum protruding position) of the cam lobe member 44 is in contact with the roller 75. Also at this time, the intake valve 25 is not lifted and is closed. From the state of FIG. 15, the first arm 72 and the second arms 73 and 74 are slightly swung in the direction in which the intake valve 25 is lifted (lift direction). However, since the rocking amount is small, the contact position of the rocker arm 24 with respect to the cam surface 77 only moves within the range of the base circle portion 81 and does not reach the lift portion 82. Therefore, the rocker arm 24 comes into contact with only the base circle portion 81 and does not contact the lift portion 82. The movement in the lift direction by the protruding portion 83 is absorbed by the mediation mechanism 70.

  Therefore, when the cam unit 42 continues to rotate in the rotation direction R, the closed state of the intake valve 25 is maintained only by repeating the state of FIG. 15 and the state of FIG.

  As described above, according to the present embodiment, since the variable lift mechanism 40 is combined with the mediation mechanism 70 and the control as described above is executed, the intake valve 25 is in the closed state even when the protrusion 83 is present. Can be maintained. In other words, even when there is a request for maintaining the intake valve closed, the protruding portion 83 can be provided, so that the degree of freedom in designing the cam lobe member 44 and thus the cam unit 42 can be increased. Since the large cam lobe member 44 that causes the protruding portion 83 can be used, it is possible to obtain the maximum lift amount equivalent to the case where the intermediate cam shaft 41 ′ is combined with the mediation mechanism 70.

  Further, in the present embodiment, when an intake valve closing maintenance request is generated, for example, when a reduced cylinder operation request is generated, the intake valve closing maintenance state can be started immediately. That is, as shown in FIG. 14, when the normal camshaft 41 ′ is combined with the mediation mechanism 70, the actuator stroke K is increased from the actuator stroke Kmax corresponding to the maximum lift amount Lmax to the actuator stroke Kmin corresponding to the minimum lift amount Lmin. It takes a relatively long time to change, for example, 1 second or more. Therefore, even if the actuator stroke K can be expanded to Kmin ′ corresponding to zero lift, it takes a relatively long time to change the actuator stroke K from an arbitrary value to Kmin ′, and after the intake valve closing maintenance request is generated The intake valve closing maintenance state cannot be started immediately.

  On the other hand, in the case of this embodiment, after the intake valve closing maintenance request is generated, the intake valve closing maintenance state can be started during one rotation of the cam unit 42, that is, within one engine cycle (= 720 ° CA). . This is because the lock release from the protruding position of the cam lobe member 44 and the lock to the retracted position can be performed during one rotation of the cam unit 42. Further, regarding the actuator stroke K, it is not necessary to change the actuator stroke K to Kmin ′ corresponding to zero lift amount (which is impossible in practice), but a predetermined value corresponding to the larger lift side (for example, equivalent to the intermediate lift amount L2). This is because the value K2 or the value K1 corresponding to the small lift amount L1 or the value Kmin corresponding to the minimum lift amount Lmin) may be changed. Therefore, in the case of this embodiment, it is possible to immediately start the intake valve closing maintenance state.

  The preferred embodiment of the present invention has been described in detail above, but various other embodiments of the present invention are conceivable. For example, the following other embodiments are possible.

  In the above embodiment, when the intake valve 25 is maintained in the closed state, the cam lobe member 44 is locked in the retracted position. However, the lock mechanism 60 can be deformed as such. It is. The point is that the lock mechanism 60 only needs to switch the locked state of the cam lobe member 44 between the locked position and the unlocked position at the protruding position. When maintaining the intake valve 25 in the closed state, the cam lobe member 44 is What is necessary is just to release the lock from at least the protruding position. Whether the cam lobe member 44 is locked in the retracted position is arbitrary. When not locked in the retracted position, the cam lobe member 44 can swing according to the external force from the roller 75, and the cam lobe member 44 protrudes from the cam base member 43 by the biasing force of the spring 52 when the roller 75 is not in contact. At the timing when the roller 75 abuts, the roller is temporarily stored in the cam base member 43 against the urging force of the spring 52. Therefore, the cam lobe member 44 repeatedly projects and retracts every time the cam unit 42 rotates. Such an embodiment is also possible.

  The mediation mechanism 70 is not limited to the structure described above, and may have a different structure having the same function.

  The embodiment of the present invention is not limited to the above-described embodiment, and includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

24 Rocker arm 25 Intake valve 40 Variable lift mechanism 43 Cam base member 44 Cam lobe member 60 Lock mechanism 70 Intermediary mechanism 71 Support shaft 72 First arm 73, 74 Second arm 77 Cam surface 81 Base circular portion 82 Lift portions 83, 84 100 Electronic control unit (ECU)
α Clip angle

Claims (1)

A variable lift mechanism for making the lift amount of the engine valve composed of an intake valve or an exhaust valve variable between a non-lift state and a lift state;
An intermediary mechanism interposed between the lift variable mechanism and the rocker arm, and for making the lift amount of the engine valve variable from a low lift side to a high lift side;
A controller configured to control the variable lift mechanism and the mediation mechanism;
With
The lift variable mechanism is
A cam base member that is rotationally driven by a driving force from the crankshaft;
A cam lobe member that is swingably connected to the cam base member, and is stored in the cam base member and corresponds to the no-lift state, and protrudes radially outward from the cam base member to correspond to the lifted state. A cam lobe member swingable between the protruding position and
A lock mechanism for switching the lock state of the cam lobe member at the protruding position;
With
The mediation mechanism is:
An input member in contact with at least one of the cam base member and the cam lobe member;
An output member having a cam surface in contact with the rocker arm;
A first portion that is provided on the cam surface and does not cause movement in the lift direction of the rocker arm;
A second portion that is provided on the cam surface and that causes the rocker arm to move in the lift direction;
A change mechanism for changing the relative positions of the input member and the output member;
With
The cam lobe member has a protruding portion that protrudes radially outward from the cam base member in the retracted position;
The control unit controls the lock mechanism to unlock the cam lobe member from the protruding position when the engine valve is maintained in a closed state, and the protruding portion of the cam lobe member in the retracted position is the input member. A variable valve operating apparatus for an internal combustion engine, wherein the change mechanism is controlled so that the rocker arm contacts the first part and does not contact the second part when contacting the first part.

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