JP4497119B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

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

  A reciprocating engine (internal combustion engine) installed in an automobile can be operated in a cylinder deactivation mode in which some cylinders are deactivated under driving conditions that do not require a large output in order to save fuel. There is an engine. In many of these engine idle mode operations, a variable valve device is used to stop lift (opening and closing) of each cylinder intake / exhaust valve in order to reduce pumping loss.

By the way, since the variable valve operating device for switching the cylinder resting mode has a simple configuration, a cam follower rocker that displaces following the cam as a rocker arm assembled to the rocker shaft, and a valve that drives the valve. Using a structure in which the cam follower rocker and the valve drive rocker are rotatably arranged on a common rocker shaft, the displacement of the cam follower, specifically the cam displacement, In this way, transmission or disconnection to the valve drive rocker is performed. Many of the switching parts that perform this transmission / reception are abutting parts that form a butting part on a cam follower rocker in which a roller for cam rolling is rotatably supported by a pair of roller yokes, and drives a valve. A structure (switching operation part) in which a slidable piston combined with an abutting part is incorporated in a valve drive rocker having a sq. Many of the abutting portions are configured to protrude laterally from the cam follower rocker and face the piston. The piston can be displaced between the position where it abuts against the abutting part and the position where it does not abut.When the piston is in a position where it abuts against the abutting part, the displacement of the cam passes from the cam follower rocker to the valve drive rocker. When it is transmitted to the valve and the piston is not in contact with the abutting part, the movement of the abutting part is released and the cam follower rocker is swung away so that the cam displacement is not transmitted to the valve drive rocker. (See Patent Document 1).
JP-A-2005-90408

  However, such a cam follower rocker has a cam follower because the portion where the cam displacement is input and the abutting portion where the cam displacement is output are significantly displaced in the axial direction of the rocker shaft. When transmitting cam displacement from the rocker to the valve drive rocker, stress is likely to occur in the torsional direction (the direction in which the overhanging abutting part collapses) due to the applied load.

  The generation of such stress may affect the required movement of the cam follower rocker, that is, the movement that transmits the cam displacement, or the rigidity of the cam follower rocker. There is a problem.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine in which the occurrence of stress in the torsional direction of the cam follower rocker is suppressed.

  One aspect of the present invention is a camshaft having a cam provided rotatably in an internal combustion engine;
  A rocker shaft arranged in parallel with the camshaft, a valve that can be driven by the cam, a cam follower rocker that is pivotally provided on the rocker shaft and is displaced following the cam, and a rocker shaft. A valve drive rocker that is rotatably provided along with the cam follower rocker, and that enables transmission / reception of cam displacement from the cam follower rocker, and a switch that transmits the displacement of the cam follower rocker to the valve drive rocker. A switching operation portion provided in one of the cam follower rocker and the valve drive rocker, and a switch actuating portion provided in either the cam follower rocker or the valve drive rocker. The cam follower rocker is rotatably supported by a pair of roller yokes and the roller yokes.
The roller has a roller that is in rolling contact with the cam, and the one roller yoke and the switching portion are continuously connected in a straight line by a rib extending from the roller yoke, and the one roller yoke is connected to the switching portion. The roller yoke and the butting portion are both arranged in a straight line with respect to the switching operation portion, and the ribs provide a gap between the switching portion and the roller yoke. Is characterized in that a rigid body portion is formed between the switching portion and the roller yoke, which are connected in a straight line along the load input / output direction and are in a positional relationship facing each other.

  Another aspect of the present invention is characterized in that the rib rises gradually following the roller yoke and moves toward the switching portion with a change in cross section that is gradually enlarged.

  Another aspect of the present invention is characterized in that a seat portion for receiving a load from a pusher for pressing the roller against the cam is formed on the other roller yoke.

  In another aspect, the switching portion is provided in either the cam follower rocker or the valve drive rocker, communicates with an oil passage provided in the rocker shaft, and has a window and a cylinder. A switching operation portion comprising a piston that is slidably inserted and either the cam follower rocker or the valve drive rocker is provided on the other side, and can enter and exit the window portion. An abutting portion capable of contacting the piston is provided, and the rib connects a switching portion provided in a cam follower rocker and the roller yoke.

According to one aspect of the present invention, the rigidity from one of the roller yokes to which the cam displacement is input through the roller to the switching unit to which the cam displacement is output is enhanced by the ribs that use the roller yoke as a reinforcing member.

  Therefore, the occurrence of stress in the torsional direction of the cam follower rocker when transmitting the cam displacement from the cam follower rocker to the valve drive rocker can be suppressed, the smooth movement of the cam follower rocker and the rigidity can be ensured. Performance and durability can be improved.

According to the aspect of the present invention, since the roller yoke, the rib, and the switching portion are aligned in a straight line in the rotational direction of the cam follower rocker, the most effective reinforcement using the roller yoke as a reinforcing member can be performed. In addition, since the displacement between the roller yoke and the switching portion, which causes the generation of stress in the torsional direction, is suppressed, the generation of torsional stress can be effectively suppressed, and at the same time, the protrusion of the abutting portion is suppressed. The cam follower locker can be made compact as a whole.

According to another aspect, the roller yoke is used to form the pusher installation seat, so that it is not necessary to provide a dedicated member for installing the pusher, and compactness is not impaired.

According to another aspect, even in the structure including the abutting portion and the switching operation portion incorporating the slidable piston in the cylinder, it is possible to secure rigidity and improve engine performance and durability. .

[One Embodiment]
Hereinafter, the present invention will be described based on an embodiment shown in FIGS.

  FIG. 1 is a perspective view of an engine (internal combustion engine), for example, a V-type 6-cylinder reciprocating engine (hereinafter simply referred to as a V-type engine) viewed from the rear, and FIG. 2 is a variable valve operating system for intake and exhaust valves of the engine. FIG. 3 is a plan view of the valve operating device (in the direction of arrow A in FIG. 1), FIG. 4 is a plan view showing various cams of the valve operating device, and FIGS. 9 is a perspective view showing a variable valve gear on the intake side, FIG. 10 is an exploded view of the device, and FIG. FIG. 12 is an exploded view of the variable valve device, FIG. 12 is an exploded view of the device, and FIG. 13 is a diagram showing valve characteristics provided by both devices. In FIG. 1, Fr indicates the front of the V-type engine.

  In FIG. 1, reference numeral 1 denotes an engine body of a V-type engine. The engine body 1 has, for example, a V-shaped cylinder block, specifically, a cylinder having a common crankcase portion 2 at the lower portion and a V-shaped deck cylinder portion 4 in which, for example, three cylinders 3 are distributed at the upper portion. The block 5 and a part such as a cylinder head 6 mounted on the head of each deck cylinder unit 4 are combined. FIG. 1 does not show fine parts such as a head cover and an oil pan. And from each deck cylinder part 4, cylinder head 6, etc., the left and right banks 7a and 7b projecting in a V shape (left and right are determined based on the forward direction) are configured. A piston 8 is reciprocally accommodated in the cylinder 3 of each bank 7a, 7b (shown in FIG. 2), and a crankshaft (not shown) is incorporated in the crankcase portion 2. However, the banks 7a and 7b are offset in the front-rear direction so that connecting rods (not shown) extending from the pistons 8 are arranged side by side on the axis of the crankshaft.

  As shown in FIG. 2, combustion chambers 11 are respectively formed on the lower surface of each cylinder head 6 facing the cylinder 3. In each of these combustion chambers 11, two (a plurality of) intake ports 12 a, 12 b and two intake ports 12 a, 12 b are opened and closed inside the bank 7 a, 7 b as shown in FIG. Intake valves 13a and 13b are provided. Similarly, two (a plurality) exhaust ports 14a and 14b and two exhaust valves 15a and 15b for opening and closing the exhaust ports 14a and 14b are provided on the outside, and combustion air is sucked from the inside of the bank. The structure is such that the gas after combustion is discharged from the outside. The intake valves 13a and 13b and the exhaust valves 15a and 15b all have a normally closed structure that is biased in the closing direction by a valve spring (not shown).

  The cylinder heads 6 of the left and right banks 7a and 7b are each provided with a single over head camshaft (SOHC) type valve system 17 that can change the lift operation of the intake and exhaust valves. Among them, the valve system 17a in the left bank includes a variable valve device 18 for intake (which can be switched between three modes) that can be switched between a normal (low speed) mode, a high speed mode, and a cylinder deactivation mode (mode in which the cylinder is deactivated). The structure is a combination of the variable valve device of the present application) and a variable valve device 19 for exhaust that can be switched between a normal (low speed) mode and a non-cylinder mode (a mode in which the cylinder is deactivated) (two-mode switching). Used. The right valve system 17b includes a variable valve device 20 for intake that can be switched between a normal (low speed) mode and a high speed mode (two-mode switching), and a valve gear 21 that is only in the normal (low speed) mode. A combined structure is used.

  FIG. 2 shows variable valve gears 18, 19 (both intake and exhaust) for one cylinder of the valve train 17a mounted on the left bank 7a (viewed from the rear of the engine). Figure). FIG. 9 shows a view of the variable valve device 18 from the inside, FIG. 10 shows an exploded view of the device 18, and FIG. 11 shows the variable valve device 19 from the inside. FIG. 12 shows an exploded view of the device 19.

  2 and 3, reference numeral 25 denotes a rotatable camshaft disposed along the longitudinal direction of the cylinder head 6 at the top center of the combustion chamber 11, and 26 denotes the camshaft. An intake side rocker shaft (corresponding to the rocker shaft of the present application) disposed (fixed) substantially in parallel with the camshaft 25 on the inner side of the bank 25, and 27 is substantially the same as the camshaft 25 on the opposite side (outside the bank). An exhaust-side rocker shaft disposed (fixed) in parallel is shown. The rocker shafts 26 and 27 are both arranged on the upper side of the camshaft 25.

  Among these, in the rocker shaft 27, an oil passage 27 a for changing cylinder rest is formed along the axial direction. Within the rocker shaft 26, an idle passage switching oil passage 26 a connected to the end of the oil passage 27 and a high speed switching oil passage 26 b are formed along the axial direction.

  The camshaft 25 is a component that is rotationally driven by a crank output. For example, as shown in FIGS. 2 and 4, a high-speed intake cam 30 and a liftless cam (pause cam) 31 are sequentially provided from the rear side as shown in FIGS. 2 and 4. An exhaust cam 32 and a low-speed intake cam 33 are formed. The low-speed intake cam 33 has a cam profile set to an opening / closing timing and a valve lift amount suitable for low-speed operation of the engine, and the high-speed intake cam 30 is an opening / closing timing and valve lift amount suitable for high-speed operation of the engine. The liftless cam 31 has a cam profile (only the base circle) having the same radius. Of course, the exhaust cam 32 has a cam profile of opening / closing timing and valve lift amount suitable for discharging combustion gas.

  The variable valve device 18 for intake uses a split rocker arm structure as shown in FIGS. 2, 9 and 10. This includes a valve drive rocker 35 (corresponding to the valve drive rocker of the present application) that drives the intake valves 13a and 13b, and low and high speed cam follower rockers 60 and 70 that follow the intake cams 30 and 33 (both are both). The structure divided into the cam follower rocker of the present application is used.

  Specifically, as shown in FIG. 2 and FIG. 10, the valve drive rocker 35 is a cylindrical rocker shaft supporting boss part 36 and is arranged in the axial direction protruding in the diameter direction from both ends of the boss part 36. A pair of (two) rocker arm portions 37, an adjustment screw portion 38 (corresponding to the contact portion of the present application) assembled to the end of the rocker arm portion 37, and modes provided at each root portion of the arm portion 37 It has switching operation parts 40a, 40b for switching. Then, as shown in FIG. 2, the rocker shaft supporting boss portion 36 extends over the portion of the rocker shaft 26 corresponding to the point from the point where the intake cam 30 (for high speed) is present to the point where the intake cam 33 (for low speed) is present. The adjusting screw portion 38 at the tip of each rocker arm portion 37 is positioned at the upper end (valve stem end) of each of the intake valves 13a and 13b. In other words, when the valve drive rocker 35 swings about the rocker shaft 26 as a fulcrum, the end of the adjusting screw portion 38 contacts the valve stem end to drive the intake valves 13a and 13b.

  Further, from the outer peripheral surface portion corresponding to the liftless cam 31 in the outer peripheral surface of the boss portion 36, as shown in FIGS. 3, 4, and 8 to 10, the slipper 41 is lifted by the liftless cam 31. It protrudes toward the outer peripheral surface. The protruding length of the slipper 41 is set such that the tip of the slipper 41 contacts the outer peripheral surface of the liftless cam 31 when the intake valves 13a and 13b are closed. With this slipper 41, when the intake valves 13a and 13b are closed, the entire valve drive rocker 35 is prevented from moving carelessly by utilizing the reaction force of the valve springs of the intake valves 13a and 13b. ing.

  A piston type is used for each of the switching operation portions 40a and 40b disposed at both ends of the boss portion 36. Of these, the switching portion 40a disposed on the intake cam 33 (for low speed) side will be described. 43 in FIGS. 5, 9, and 10 is a cylindrical shape formed at the root portion of the arm portion 37 on the intake cam 33 side. Cylinder. The cylinder 43 has a vertical shape extending along the diameter direction of the rocker shaft 26. A window portion 44 is formed in the lower portion of the front surface of the cylinder 43 (the surface on the camshaft 25 side). A through hole 45 (shown only in FIG. 5) having a smaller diameter than the cylinder 43 is formed from the bottom surface of the cylinder 43 to the inner surface 36a (bearing surface) of the boss portion 36 immediately below the cylinder 43. A piston 46 (corresponding to the piston of the present application) is accommodated in the cylinder 43 together with a compression spring 47 that urges the piston 46 to the bottom surface of the cylinder 43 (shown only in FIG. 5). As a result, the window portion 44 of the cylinder 43 is normally closed by the lower outer peripheral surface of the piston 46, and when the piston 46 rises, the piston 46 is retracted from the window portion 44 so that the window portion 44 is opened. It is. A pin 48 is slidably accommodated in the through hole 45 as shown in FIG. As shown in FIG. 5, the lower end opening of the through hole 45 is a branch passage 49 branched from the oil passage 26a, more specifically, a branch passage 49 branched from the oil passage 26a in the radial direction and opened to the outer peripheral surface of the rocker shaft 26. When the hydraulic pressure is applied to the pin 48 from the oil passage 26a, the piston 43 that has closed the window 44 as shown by the two-dot chain line in FIG. Driving is performed in the direction to be applied, that is, the window portion 44 is opened (the window portion 44 can be opened even with a low oil pressure by the small diameter pin 48).

  As with the switching operation portion 40a, the switching operation portion 40b disposed on the intake cam 30 (for high speed) side has a cylindrical cylinder at the base portion of the arm portion 37 as shown in FIGS. A structure in which 51 is formed is used. The cylinder 51 extends to the inner surface 36a of the boss portion 36 in order to earn a stroke amount. Therefore, a through hole 52 communicating with the cylinder 51 in series is formed in the rocker shaft 26 portion immediately below the cylinder 51. The through hole 52 has a smaller diameter than the cylinder 51. Further, unlike the switching operation portion 40a, as shown in FIG. 6, a window portion 50 is formed in the upper front portion of the cylinder 51, and a piston 53 (corresponding to the piston of the present application) is provided in the cylinder 51. 53 is accommodated together with a compression spring 54 for urging 53 to the bottom surface of the cylinder 51. The piston 53 is thin enough to fit in the lower cylinder portion from the window portion 50. In contrast to the switching operation portion 40a, the opening of the window portion 50 of the cylinder 51 is normally open. When the piston 53 is raised, the outer peripheral surface of the piston 53 is closed. A pin 55 is slidably accommodated in the through hole 45. As shown in FIG. 6, the lower end portion of the through hole 52 intersects and communicates with a part of the oil passage 26b. When hydraulic pressure is applied from the oil passage 26b to the pin 48, the pin 55 moves upward. 6, the piston 53 is driven in a direction to close the window portion 50, that is, the window portion 50 is closed (the window portion 50 can be closed by a small diameter pin 55 even at low oil pressure).

  It should be noted that the opening rims on both ends of the boss portion 36 are cut out from the bottom of the cylinders 43 and 51 to the front of the boss portion 36 (the side without the arm portion 37) to the root portion of the arm portion 37, respectively. A pair of notches 57 is formed (shown in FIG. 10).

  The cam follower rocker 70 on the high speed side is adjacent to the end of the boss portion 36 (valve drive rocker) on the intake cam 30 (for high speed) side as shown in FIGS. 2, 3, 6, 9 and 10. It is a part arranged in this way. The cam follower rocker 70 includes a cylindrical rocker shaft supporting boss portion 71 that is rotatably inserted into the rocker shaft 26 adjacent to the end of the boss portion 36, and one end side from both ends of the boss portion 71. A pair of roller support pieces 72 which are a pair of roller yokes protruding linearly directly above the intake cam 30 (for high speed), and a rotatable roller 73 supported between the tip portions of the roller support pieces 72 (this application) And an abutting portion 79 formed on the upper peripheral wall of the boss portion 71. That is, the cam follower rocker 70 has the roller 73 on one end side and the abutting portion 79 on the other end side. Of these, the roller 73 is in rolling contact with the intake cam 30. When the cam shaft 25 rotates, the cam follower rocker 70 swings while following the displacement of the intake cam 30 with the boss portion 71 as a fulcrum.

  More specifically, the end portion of the boss portion 71 adjacent to the boss portion 36 (valve drive rocker) is provided with an edge portion 36b remaining at the open end of the boss portion 36 as shown in FIGS. A notch 76 (only part of which is shown) is formed. Due to the fitting of the irregularities, the entire cam follower rocker 70 is arranged at a point (displaced point) close to the valve drive rocker 35 side by the notch. As shown in FIG. 9 and FIG. 10, the abutting portion 79 is disposed at a point facing the window portion 50 from the approach of the boss portion 71. The roller support piece 72 on one side of the roller support piece 72, that is, closer to the boss portion 36 (inner side) is disposed at a point substantially facing the abutting portion 79. Due to the arrangement of the roller support pieces 72, deviation from the abutting portion 79 (in the axial direction of the rocker shaft 26) is suppressed. Thus, both the roller support piece 72 on one side and the abutting part 79 are arranged so as to be aligned with the window part 50 in a straight line. Further, as shown in FIGS. 9 and 10, a wing portion 74 is provided on the outer peripheral surface of the boss portion 71 so as to extend from the abutting portion 79 to the roller support piece 72 on the inner side (near the boss portion 36). The wing portion 74 is formed by a rib 78 that continuously connects the abutting portion 79 to the roller support piece 72 in a straight line. Specifically, the rib 78 is directed toward the abutting portion 79 with a cross-sectional change in which the rib 78 gradually rises following the roller support piece 72 and gradually increases in width. By this rib 78, the abutting portion 79 and the roller support piece 72 are connected in a straight line along the load input / output direction, and between the abutting portion 79 and the roller support piece 72 that are in a directly-facing positional relationship. The rigid body part is formed on. In other words, it is reinforced. More specifically, the rib 78 is disposed around the notched portion in the portion where the notched portion 76 is formed, so that the cross section forms an inverted L-shaped cross section. The abutting portion 79 is formed by making the horizontal wall at the tip end portion of the rib 78 into a shape that can enter and exit the window portion 50. Thus, in a normal state, the abutting portion 79 goes in and out of the cylinder 51 through the window portion 50, and when the window portion 50 is blocked by the piston 53, the abutting portion 79 is exposed from the window portion 50. Abutting against the piston 53 is made. In other words, whether the displacement of the high-speed intake cam 30 from the cam follower rocker 70 is input to the valve drive rocker 35 or the input is stopped depending on whether the abutting portion 79 is swung or abutted against the piston 53. (Switching mechanism: switching unit). In addition, the notch part 57 and the notch part 76 are set to the magnitude | size and shape which do not inhibit the motion of the cam follower rocker 70. FIG.

  On the front end side of the outer roller support piece 72, a receiving seat 75 (corresponding to the seat portion of the present application) for installing a pusher 70a (partially shown by a two-dot chain line in FIG. 6) for pressing the roller 73 against the intake cam 30. That is, the cam follower rocker 70 has a structure in which the pusher 70a can be installed using the existing roller support piece 72.

  The low-speed cam follower rocker 60 is a component arranged adjacent to the end of the boss portion 36 on the intake cam 33 (for low speed) side as shown in FIGS. 2, 3, 9 and 10. . The cam follower rocker 60 is structurally the same as the cam follower rocker 70 on the high speed side described above, except that the cam follower rocker 70 is the opposite. For this reason, in the description of each part of the cam follower rocker 60, instead of the reference numerals 71 to 79 of the respective parts of the cam follower rocker 70, the same parts are denoted by reference numerals 61 to 69 in which the second digit numbers are changed. , Omit that.

  As a result, the cam follower rocker 60 also has an inner roller support piece 62 (disposed closer to the boss portion 36) on one end side, like the cam follower rocker 70, as shown in FIGS. However, the abutting portion 69 and the inner roller support piece 62 are arranged in a straight line with respect to the point facing the abutting portion 69 on the other end side, specifically, the window portion 44. The abutting portion 69 and the inner roller support piece 62 are connected (coupled) by ribs 68 extending linearly from the abutting portion 69 to the roller support piece 62.

  As shown in FIG. 5, when the cam follower locker 60 is in a normal state, the abutting portion 69 abuts against the piston 46 closing the window portion 44, and when the window portion 44 is opened by the piston 46, The abutting portion 69 enters and exits the cylinder 43 through the window portion 44. That is, whether the displacement of the low-speed intake cam 33 from the cam follower rocker 60 is input to the valve drive rocker 35 or the input is stopped depending on whether the abutting portion 69 hits the piston 46 or swings idly. Switching can be performed (switching mechanism: switching unit).

  On the other hand, the variable valve device 19 for exhaust is driven by a cam follower rocker 80 that follows the exhaust cam 32 and exhaust valves 15a and 15b as shown in FIGS. 2, 7, 11 and 12. A split rocker arm structure divided into a valve drive rocker 90 is used.

  Among these, the cam follower rocker 80 includes a cylindrical rocker shaft supporting boss portion 81 that is rotatably inserted into a rocker shaft 27 corresponding to the exhaust cam 32, and exhaust cams from both ends of the boss portion 81. A U-shaped roller support piece 82 projecting linearly directly above 32, a rotatable roller 83 supported between the tip portions of the roller support piece 82, and a wing portion 84 formed on the boss portion 81. The structure we have is used. Here, the roller 83 is in rolling contact with the exhaust cam 32, and the cam follower rocker 80 pivots around the boss 81 when the cam shaft 25 rotates, that is, swings while following the displacement of the exhaust cam 25. I have to do it. The cam follower rocker 80 is provided with a roller 83 by an urging force of a pusher 80a (only part of which is shown by a two-dot chain line in FIG. 7) inputted from a receiving seat 85 formed on the roller support piece 82 in order to maintain followability. Is pressed against the exhaust cam 32.

  The wing portion 84 is formed from a rib 86 that projects from the center of the outer surface of the boss portion 81 in the width direction. The rib 86 extends from the rear end portion of the roller support piece 82 to the upper portion of the boss portion 81 along the circumferential direction of the boss portion 81. An abutting portion 89 having a shape protruding forward is formed at the tip of the rib 81.

  As shown in FIGS. 11 and 12, the valve drive rocker 90 has a portal structure. The rocker 90 uses a structure in which a pair of rocker arm portions 91 (plural: two) disposed on both sides of the boss portion 81 (cam follower rocker 80) and a mode switching operation portion 98 are combined. ing.

  Of these, the pair of rocker arm portions 91 is used for supporting a pair of cylindrical rocker shafts that are rotatably fitted to the rocker shaft 27 portions on both sides of the boss portion 81 (cam follower rocker 80) at one end. The other boss part 92 is used, and the other end part is provided with an arm part 93 extending linearly from the boss part 92 to the exhaust valves 15a and 15b. And the adjustment screw part 94 which makes the front-end | tip part of each arm part 93 is arrange | positioned at the upper end (valve stem end) of exhaust valve 15a, 15b, respectively. The arm portions 93 and 93 are connected by, for example, a plate-like connecting arm 95 at a point where the end of the arm portion 93, specifically, the adjusting screw portion 94 is provided. When the valve drive rocker 90 swings about the rocker shaft 27 as a fulcrum, the plurality of exhaust valves 15a and 15b are driven.

  A slipper 96 projects from the outer peripheral surface of the boss portion 92 disposed immediately above the liftless cam 31 toward the outer peripheral surface of the liftless cam 31 as shown in FIGS. 4, 8, and 12. The protruding length of the slipper 96 is set such that the tip of the slipper 96 comes into contact with the outer peripheral surface of the liftless cam 31 when the exhaust valves 15 a and 15 b are closed. With this slipper 96, when the exhaust valves 15a and 15b are in the closed state, the entire rocker arm portion 91 is prevented from moving carelessly using the reaction force of the valve springs of the exhaust valves 15a and 15b. Yes.

  As shown in FIGS. 10 and 12, the switching operation portion 98 is provided at the connecting arm 95, specifically, at the arm portion that is substantially at the center between the exhaust valves 15 a and 15 b. The switching operation unit 98 is a piston type.

  Referring to FIG. 7, reference numeral 99 denotes a vertical cylinder. The cylinder 99 is formed so as to protrude upward from the center of the connecting arm 95 (a point that is approximately the center between the exhaust valves 15a and 15b). The cylinder 99 is inclined backward in a direction away from the rocker shaft 27. A window portion 100 is formed in the lower portion of the front surface (the surface on the camshaft 25 side) of the cylinder 99. A through hole 101 having a smaller diameter than that of the cylinder 99 is formed from the bottom surface of the cylinder 99 to the inside of the arm portion immediately below the cylinder 99.

  A piston 102 is accommodated in the cylinder 99 together with a compression spring 103 that urges the piston 102 toward the bottom surface of the cylinder 99. That is, normally, the window portion 100 of the cylinder 99 is closed by the outer peripheral surface of the piston 102, and when the piston 102 moves up, the piston 102 is retracted from the window portion 100 and the window portion 100 is opened. is there. A pin 104 is slidably accommodated in the through hole 101. The lower end opening of the through hole 104 communicates with the relay path 105 formed inside the connecting arm portion 95 as shown in FIGS. 3 and 7. The relay path 105 opens on the inner surface of the boss portion 92 through a relay path 106 formed inside the arm portion 93. Further, the relay path 106 communicates with a branch path 107 (shown only in FIG. 7) branched from the oil path 27a, more specifically, a branch path 107 branched radially from the oil path 27a and opened to the outer peripheral surface of the rocker shaft 26. When oil pressure is applied to the pin 104 from the oil passage 27a, the piston 104 that has closed the window 100 as shown by a two-dot chain line in FIG. Driving, that is, the window 100 is opened.

  Immediately before this window portion 100, the abutting portion 89 of the cam follower rocker 80 is positioned. As shown in FIG. 7, the abutting portion 89 is formed in a shape that can enter and exit the window portion 100. Thus, in a normal state, the abutting portion 89 abuts against the piston 102 blocking the window portion 100, and when the window portion 100 is opened, the abutting portion 89 enters and exits the cylinder 99 through the window portion 100. I have to do it. That is, the switching of whether the displacement of the exhaust cam 32 from the cam follower rocker 80 is input to the valve drive rocker 90 or the input is stopped depending on whether the abutting portion 89 abuts against the piston 102 or is swung. (Switching mechanism: switching unit).

  On the other hand, the oil passage 27a of the rocker shaft 26 on the exhaust side is formed by a hydraulic pressure supply unit (oil pump or the like) via an oil control valve 120 (hereinafter referred to as OCV 120) for changing cylinder rest as shown in FIG. Connected: not shown). The oil passage 26b of the rocker shaft 26 on the intake side is connected to a hydraulic pressure supply unit (formed by an oil pump or the like: not shown) via an oil control valve 121 (hereinafter referred to as OCV 121) for high speed switching. Yes. The OCVs 120 and 121 of the two hydraulic supply systems are both connected to a control unit 122 (for example, constituted by a microcomputer). For example, according to a map set in advance according to the driving state of the vehicle, the control unit 122 “closes” both the OCVs 120 and 121 in the low speed mode, and “opens” only the OCV 121 in the high speed mode. In the non-cylinder mode, a function is set in which only the OCV 120 is “open”.

  Such a structure is adopted for each cylinder 3 of the left bank 7a. That is, in the intake system of the left bank 7a, three-stage switching can be performed: valve drive by the high-speed intake cam 30, valve drive by the low-speed cam 33, and non-valve drive. In the exhaust system, valve drive by the exhaust cam 32 and non-drive Two-stage switching of valve drive can be performed.

  On the other hand, each intake variable valve operating device 20 of the valve operating system 17b of the right bank 7b has a structure in which a mechanism or a part that is non-valve driven is removed from the intake variable valve operating device 18 of the left bank 7a. It has been. Although not shown in the figure, the low-speed side switching structure (mainly the switching operation portion 40a and the cam follower rocker 60) is omitted, and the valve drive rocker 35 is always directly connected to the low-speed intake cam 33. A driven structure is used. Thus, only the switching structure on the high speed side is left, and the two-stage switching between the low speed mode and the high speed mode can be performed. On the exhaust side, only the valve drive rocker 90 is always directly and directly connected to the exhaust cam 32 by removing the non-valve drive mechanism and parts from the variable valve device 19 for exhaust of the left bank 7a. A driven structure is used. Further, the right bank 7b employs a structure in which the oil passages 26a, 27a for switching the cylinder rest mode are omitted and only the oil passage 26b is left. That is, the right bank 7b has a structure in which the valve drive by the high-speed intake cam 30 and the valve drive by the low-speed cam 33 can be switched in two stages in the intake system, and only the valve drive by the exhaust cam 32 can be performed in the exhaust system. .

  With the valve trains 17a and 17b of the left and right banks 7a and 7b, an operation in which some cylinders (three cylinders of the left bank 7a) are stopped can be performed.

  Next, the operation of the valve train 17 will be described with reference to FIGS.

     Now, it is assumed that the control unit 122 is instructed to execute the low speed mode depending on the traveling state of the automobile.

  Then, the OCV 120 and 121 are both closed by the control unit 122. That is, the oil passages 26a, 26b, and 27a are all in a state where the hydraulic pressure from the hydraulic pressure supply system does not act. Thereby, as shown by the solid line in FIG. 5, the window portion 44 of the switching operation portion 40 a (intake air) of the left bank 7 a is blocked by the piston 46 (by the elastic force of the compression spring 47). Further, as shown by the solid line in FIG. 6, the window portion 50 of the switching operation portion 40 b (intake) is opened (due to the elastic force of the compression spring 54). Further, as shown in FIG. 7, the window portion 100 of the switching operation portion 98 (exhaust) of the left bank 7a is blocked by the piston 102 (by the elastic force of the compression spring 103).

  Then, on the intake side of the left bank 7a, the cam follower rocker 70 (high speed) is driven to swing while being idle. At the same time, the cam follower rocker 60 (low speed) is driven to swing while abutting against the piston 46. On the exhaust side of the left bank 7a, the cam follower rocker 80 is driven to swing while abutting against the piston 102.

  As a result, on the intake side, the displacement of the intake cam 33 (for low speed) transmitted from the cam follower rocker 60 is transmitted from the valve drive rocker 35 to the pair of rocker arm portions 37 to the pair of intake valves 13a and 13b. 13a and 13b are driven. On the exhaust side, the displacement of the exhaust cam 32 transmitted from the cam follower rocker 80 passes through a pair of arm portions 93 extending in parallel from the connecting arm 95 of the valve drive rocker 90 toward the valve end, and a pair of exhaust valves 15a. , 15b to drive the exhaust valves 15a, 15b.

  In the variable valve gear 20 of the right bank 7b, the cam follower rocker (high speed) is accompanied by the idling of the cam follower rocker (high speed), so that only the displacement of the low speed intake cam transmitted to the valve drive rocker is transferred to the pair of intake valves. Then, the intake valve is driven. Further, in the exhaust-side valve gear 21, the displacement of the exhaust cam is directly transmitted to the pair of exhaust valves via the pair of arm portions via the valve drive rocker to drive the exhaust valves.

  As a result, the V-type engine is operated in the low-speed mode provided by the combination of the low-speed cam and the exhaust cam in the diagram of FIG. That is, the engine performance required for normal travel is output.

  Further, when a command to execute the high-speed mode is given by the control unit 122 according to the running state of the automobile, the control unit 122 performs control to open only the OCV 121 for high-speed switching. As a result, the hydraulic pressure acts only on the oil passage 26b.

  Then, hydraulic pressure is applied to the pin 55 of the switching operation part 40b (intake side) of the left bank 7a. As a result, the window portion 50 is blocked by the piston 53 driven upward by the pin 55 as indicated by a two-dot chain line in FIG. Note that the exhaust bank side of the left bank 7a continues to be in a state where the window portion 100 of the switching operation portion 98 is blocked by the piston 102.

  Then, the cam follower rocker 70 on the intake side is driven to swing while abutting against the piston 53 as indicated by a two-dot chain line in FIG.

Here, the window portion 44 of the switching operation portion 40a is in a state of being blocked by the piston 46, but the outer shape of the high-speed intake cam 30 is set larger than that of the low-speed intake cam 33. Only the cam displacement of the intake cam 30 (for high speed) transmitted from the cam follower rocker 70 is transmitted from the valve drive rocker 35 to the pair of intake valves 13a and 13b via the pair of rocker arm portions 37. That is, the intake valves 13a and 13b are driven by the high-speed intake cam 30. The exhaust valves 15a and 15b continue to be driven by a path in which the displacement of the previous exhaust cam 32 is transmitted from the cam follower rocker 80 to the connecting arm 95 of the valve drive rocker 90. In the variable valve gear 20 of the right bank 7b, As in the left bank 7a, the displacement of the intake cam (for high speed) transmitted from the cam follower rocker is transmitted from the valve drive rocker to the pair of intake valves via the pair of rocker arms, thereby driving the intake valve. . The valve gear 21 of the right bank 7b continues to drive the pair of exhaust valves directly by the valve drive rocker.

  As a result, the V-type engine is operated in the high speed mode provided by the combination of the high speed cam and the exhaust cam in the diagram of FIG. That is, it switches to the driving | operation which outputs high engine performance.

  Further, when the control unit 122 gives a command to execute the idle cylinder mode according to the traveling state of the automobile, the controller 122 performs control to open only the idle cylinder OCV 120. Thereby, the hydraulic pressure acts on the oil passages 26a, 27a.

  Then, on the intake side of the left bank 7a, hydraulic pressure is applied to the pin 48, and the pin 48 is driven upward. Thereby, the piston 46 of the switching operation part 40a is driven upward, and the window part 44 is opened as shown by a two-dot chain line in FIG. Further, since the hydraulic pressure is not applied to the switching operation portion 40b, the window portion 50 continues to be opened as shown in FIG. Even on the exhaust side, the piston 102 of the switching operation unit 98 is driven upward by the push-up of the pin 104. Thereby, the window part 100 of the switching operation part 98 is open | released.

  As a result, each cam follower rocker 60 (intake: low speed), cam follower rocker 70 (intake: high speed), and cam follower rocker 80 (exhaust) in the left bank 7a are driven to oscillate with idling. The driving force for driving the valve is not transmitted to the drive rockers 35 and 90 (intake and exhaust). Accordingly, as shown in FIG. 8, the slippers 41 and 96 of the valve drive rockers 35 and 90 are kept in sliding contact with the circular cam surface (outer peripheral surface) of the liftless cam 31, and the intake valves 13 a and 13 b and the exhaust valve are exhausted. Both valves 15a and 15b are kept closed. The cam follower lockers 60, 70, 80 are continuously pressed against the cam surface by the pushers 60a, 70a, 80a.

  The lift (opening / closing) of the intake valves 13a, 13b and the exhaust valves 15a, 15b in the left bank 7a is stopped by the disconnection between the cam follower lockers 60, 70, 80 and the valve drive rockers 35, 90.

  At this time, the variable valve gear 20 for intake and the valve gear 21 for exhaust in the right bank 7b continue to transmit the displacement of the low-speed intake cam to the intake valve, as in the low-speed mode. Since the cam displacement continues to be transmitted to the exhaust valve, the cylinder is switched to the cylinder deactivation mode in which some cylinders (the cylinders in the left bank 7a) are deactivated.

  Here, the cam follower rockers 60 and 70 both have rigidity from the one of the roller support pieces 72 to which the cam displacement is input to the abutting portions 69 and 79 to which the cam displacement is output due to the rigidity of the ribs 68 and 78. The strength has been dramatically increased. By reinforcing the ribs 68 and 78 using one of the roller support pieces 72 as a reinforcing member, generation of stress in the torsional direction generated at the boss portions 61 and 71 of the cam follower rockers 60 and 70 during operation of the engine is suppressed.

  Therefore, the smooth movement of the cam following rockers 60 and 70 and the rigidity of the cam following rockers 60 and 70 can be ensured.

  In particular, when the ribs 68 and 71 are reinforced, one of the roller support pieces 62 and 72 is opposed to the abutting portions 69 and 79 on the cam follower rockers 60 and 70, and the roller supporting pieces 62, When the structure in which up to one end of 72 is connected by ribs 68 and 69 is used, one of roller support pieces 62 and 72, ribs 69 and 79, and Since the abutting portions 69 and 79 are arranged in a straight line, the reinforcement effect by the ribs 69 and 79 appears highest, and the generation of stress in the twisting direction can be sufficiently suppressed. In addition, since the deviation between the roller support pieces 62 and 72 and the abutting portions 69 and 79 that cause the generation of stress in the torsional direction can be suppressed, the smooth movement of the cam follower lockers 60 and 70 can be ensured, and the cam follower rocker Ensuring the rigidity strength of 60 and 70 is sufficient, and engine performance and engine durability can be improved. At the same time, the cam following rockers 60 and 70 are reinforced by the ribs 69 and 70 without projecting around, so that the cam following rockers 60 and 70 can be made compact as a whole.

  In addition, the pushers 60a and 70a are installed on the roller support pieces 62 and 72 to which the remaining ribs 69 and 79 are not connected by the receiving seats 65 and 75 using the roller support pieces 62 and 72, respectively. Therefore, it is not necessary to separately provide a member for installing the pushers 60a and 70a, and the compact structure can be maintained as it is.

  Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the spirit of the present invention. For example, in one embodiment, the abutting portion is provided in the cam follower rocker and the switching operation portion is provided in the valve drive rocker. However, the abutting portion may be provided in the valve drive rocker and the switching operation portion may be provided in the cam following rocker. In addition, an example in which the present invention is applied to a V-type engine has been described. However, the present invention is not limited to this, and other engines such as other inline cylinders and DOHC engines in which rocker shafts are divided into intake and exhaust engines. You may apply to.

The perspective view which shows the engine carrying the variable valve apparatus which concerns on one Embodiment of this invention. The perspective view which shows the whole variable valve apparatus of both the intake and exhaust for 1 cylinder currently mounted in the left bank of the same engine. The top view seen from the A arrow in FIG. The top view which shows the layout of the various cams of a cam shaft. FIG. 4 is a cross-sectional view of the intake side (low speed) variable valve operating apparatus as seen from the direction of arrow B in FIG. 3. Sectional drawing of the variable valve apparatus by the side of intake (high speed) seen from C arrow in FIG. Sectional drawing of the variable valve apparatus by the side of the exhaust seen from D arrow in FIG. FIG. 4 is a cross-sectional view around a liftless cam as viewed from the direction of arrow E in FIG. The perspective view which shows the whole variable valve apparatus by the side of intake. The perspective view which decomposed | disassembled the apparatus into the cam follower rocker and the valve drive rocker. The perspective view which shows the whole variable valve apparatus by the side of exhaust. The perspective view which decomposed | disassembled the apparatus into the cam follower rocker and the valve drive rocker. The diagram for demonstrating the variable of the various valve lifts which the variable valve apparatus of intake / exhaust brings.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine body (internal combustion engine), 13a, 13b ... Intake valve (valve), 18 ... Variable movable valve device (variable valve operating device) for intake, 25 ... Camshaft, 26 ... Rocker shaft for intake, 30, 33 ... Intake cam (cam), 35 ... Valve drive rocker, 38 ... Adjust screw part (contact part), 46, 53 ... Piston, 62, 72 ... Roller support piece (roller yoke), 63, 73 ... Roller, 69 79, abutment part, 60, 70 ... cam follower rocker, 60a, 70a ... pusher, 65, 75 ... receiving seat (seat part), 68, 78 ... rib.

Claims (4)

A camshaft having a cam provided rotatably in the internal combustion engine;
A rocker shaft arranged in parallel with the camshaft;
A valve drivable by the cam;
A cam follower rocker that is pivotally provided on the rocker shaft and is displaced following the cam;
A valve-driven rocker provided on the rocker shaft so as to be rotatable along with the cam follower rocker, and capable of turning on and off the transmission of cam displacement from the cam follower rocker;
A switching unit that transmits the displacement of the cam follower rocker to the valve drive rocker,
The switching unit includes a switching operation unit provided in either the cam follower rocker or the valve drive rocker, and an abutting unit provided in either the cam follower rocker or the valve drive rocker. Prepared,
The cam follower rocker has a pair of roller yokes and a roller rotatably supported by the roller yoke and is in rolling contact with the cam. A straight line is formed by a rib extending from the roller yoke between one roller yoke and the switching portion. Connected in series ,
One roller yoke is formed at a point almost facing the switching portion,
One of the roller yokes and the abutting portion are arranged so as to be aligned with the switching operation portion,
By the rib, the switching portion and the roller yoke are connected in a straight line along the load input / output direction, and a rigid body portion is formed between the switching portion and the roller yoke that are in a directly-facing positional relationship. A variable valve operating apparatus for an internal combustion engine, characterized in that: 2. The variable valve for an internal combustion engine according to claim 1, wherein the rib is directed toward the switching portion while being accompanied by a change in cross section that gradually rises and gradually widens following the roller yoke. apparatus. The variable valve for an internal combustion engine according to claim 1 or 2, wherein a seat portion for receiving a load from a pusher for pressing the roller against the cam is formed on the other roller yoke. apparatus. The switching unit is
Provided to either of the cam follower rocker or the valve drive rocker, and a piston that is inserted slidably into the cylinder and the cylinder having a window portion while the oil passage and communicating provided on the rocker shaft A switching actuator,
Said cam follower rocker or the is found provided on either the other of the valve drive rocker, a same piston and capable of abutting the abutting portion by the sliding of the piston a possible out to the window,
The variable valve operating apparatus for an internal combustion engine according to any one of claims 1 to 3, wherein the rib connects a switching portion provided in a cam follower rocker and the roller yoke.

Images