JP2007205329A - Variable valve gear mechanism of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure the smooth movement of a control shaft by reducing the resistance of the control shaft from a lubricating oil when the control shaft is moved while effectively lubricating component parts moving relative to each other in a variable valve gear mechanism of an internal combustion engine. <P>SOLUTION: This variable valve gear mechanism 30 comprises a hollow rocker shaft (support shaft) 31, a control shaft 32 disposed in the rocker shaft 31 movably in the axial direction, and a variable valve lift mechanism 40 disposed on the rocker shaft 31. A lubricating oil is supplied between the component parts of the variable valve gear mechanism 30 moving relative to each other, for example, between the rocker shaft 31 and the control shaft 32. The control shaft 32 is formed of a hollow member in which an internal space 32b extending in the axial direction is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable valve mechanism that continuously changes the valve characteristics of an engine valve of an internal combustion engine.

  As a variable valve mechanism for an internal combustion engine (engine), the valve characteristics such as the operating angle and the maximum lift amount of the engine valve (at least one of the intake valve and the exhaust valve) are continuously changed according to the operating state of the engine. A technique for enabling change is known. When such a variable valve mechanism of an engine is applied to, for example, an intake valve, the intake valve can be limited by reducing the operating angle of the intake valve and the maximum lift amount in a low engine speed and low load range. Further, the pumping loss caused by the throttle valve opening control can be reduced, and the fuel consumption can be improved. Also, in the high engine speed and high load range, the operating angle of the intake valve and the maximum lift amount can be increased, and an increase in output can be secured by improving the intake charging efficiency.

  An example of such a variable valve mechanism for an engine is a hollow rocker shaft (support shaft) fixed to the cylinder head of the engine and provided parallel to the camshaft of the engine valve, and an axial direction within the rocker shaft. Some include a control shaft (control shaft) disposed in a movable state and a plurality of variable valve lift mechanisms disposed on the rocker shaft (see, for example, Patent Document 1). ).

  The variable valve lift mechanism is provided for each cylinder of the engine, and includes a slider gear that can move in conjunction with the control shaft, an input arm that is driven by a camshaft cam, and an output arm that lifts the engine valve. It is configured with. The input arm and the output arm are provided on the slider gear, and are disposed between the support portions that support the rocker shaft in a state where movement in the axial direction is restricted.

  A shaft insertion hole into which the control shaft is inserted is formed in the slider gear. The slider gear is formed with an input side helical spline that meshes with the input arm and an output side helical spline that meshes with the output arm. The direction of the twist of the teeth of the input side helical spline and the direction of the twist of the teeth of the output side helical spline are formed in opposite directions. On the other hand, a helical spline that meshes with the input-side helical spline of the slider gear is formed on the inner peripheral surface of the input arm, and similarly, a helical spline that meshes with the output-side helical spline of the slider gear. Splines are formed.

In the variable valve mechanism of the engine configured as described above, when the torque of the camshaft is transmitted to the input arm, the input arm is swung, and the engine valve is moved by the output arm that swings integrally with the input arm. It is supposed to be lifted. Then, the operating angle and the maximum lift amount of the engine valve are changed as follows. That is, when the slider gear is moved in the axial direction in conjunction with the movement of the control shaft in the axial direction, the relative positions of the slider gear, the input arm, and the output arm in the axial direction change. As a result, the input arm and the output arm on the slider gear are relatively rotated, the relative phase difference between the two is changed, and the operating angle and the maximum lift amount of the engine valve are continuously changed. The input arm is always pressed against the cam of the camshaft by the elastic force of the lost motion spring. The rocker arm is pressed against the output arm by the elastic force of the valve spring of the engine valve.
JP 2001-263015 A

  In the above-described variable valve mechanism of the engine, the lubricating oil is supplied to the sliding parts (including the gear meshing parts) between the constituent parts, particularly the constituent parts that move relative to each other in a state of being in contact with each other. The relative movement is ensured. For this reason, the variable valve mechanism is formed with an oil passage for supplying lubricating oil from the outside between such components. For example, an oil passage is also formed between the rocker shaft and the control shaft in order to move the control shaft smoothly in the axial direction and quickly change the operating angle and maximum lift amount of the engine valve.

  By the way, when the control shaft is not hollow but solid, the lubricating oil supplied between the rocker shaft and the control shaft can become a resistance when the control shaft moves in the axial direction. For this reason, if it is attempted to move the control shaft against the resistance of the lubricating oil, there is a problem in that the power consumption of the actuator for moving the control shaft increases, which affects fuel consumption.

  The present invention has been made in view of the above-mentioned problems of the prior art, and in a variable valve mechanism of an internal combustion engine, the movement of a control shaft while performing lubrication between components that move relative to each other more effectively. It is an object of the present invention to reduce the resistance sometimes received from the lubricating oil and to ensure smooth movement of the control shaft.

  In the present invention, means for solving the above-described problems are configured as follows. That is, the present invention comprises a hollow support shaft, a control shaft disposed in an axially movable state in the support shaft, and a variable valve lift mechanism disposed on the support shaft, The variable valve lift mechanism includes a slider driven in the axial direction in conjunction with a control shaft, an input arm that engages with a helical spline formed on the outer peripheral surface of the slider and receives a force from a camshaft, An output arm that engages with the helical spline formed in a direction different from the helical spline that engages with the input arm on the outer peripheral surface of the slider and lifts the engine valve is provided. In a variable valve mechanism for an internal combustion engine that changes the valve characteristics of an engine valve by movement and supplies lubricating oil through an oil passage between components that move relative to each other. It is characterized in that the control shaft is made hollow.

  In such a variable valve mechanism for an internal combustion engine, when the torque of the camshaft is transmitted to the input arm, the input arm is swung, and the engine valve is lifted by the output arm that swings integrally with the input arm. The Further, the valve characteristics such as the working angle and the maximum lift amount of the engine valve are changed as follows. That is, when the slider is moved in the axial direction in conjunction with the movement of the control shaft in the axial direction, the relative positions of the slider, the input arm, and the output arm in the axial direction change. As a result, the input arm and the output arm on the slider rotate relative to each other, the relative phase difference between them changes, and the valve characteristic of the engine valve changes continuously. Further, lubricating oil is supplied through an oil passage between sliding portions (including gear meshing portions) between components that move relative to each other, for example, between a support shaft and a control shaft.

  According to the above configuration, when changing the valve characteristic of the engine valve by moving the control shaft in the axial direction, the lubricating oil between the support shaft and the control shaft can become a resistance. Since the shaft is formed hollow, the cross-sectional area of the control shaft when cut along a plane perpendicular to the axial direction is smaller than when the shaft is solid rather than hollow. Thereby, compared with the case where a control shaft is solid, the resistance received from lubricating oil at the time of the movement of an axial direction of a control shaft can be reduced. Then, smooth movement of the control shaft can be ensured, and the valve characteristics of the engine valve can be changed quickly.

  Also, even if the control shaft is moved against the resistance received from the lubricating oil, the power consumption of the actuator for driving the control shaft can be saved compared to the case where the control shaft is solid. The influence can be reduced. Moreover, since the internal space of the control shaft forms part of an oil passage for supplying lubricating oil between the components that move relative to each other in the variable valve mechanism, the space between the components that move relative to each other is formed. Lubrication can be performed more effectively, and the degree of freedom in designing the lubrication path can be improved.

  According to the present invention, since the control shaft is formed hollow, the resistance received from the lubricating oil when the control shaft is moved can be reduced while performing lubrication between the components that move relative to each other more effectively. Smooth movement can be ensured.

  The best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  Hereinafter, an example in which the variable valve mechanism of the present invention is applied to an internal combustion engine (engine) mounted on a vehicle will be described. In the following example, a case where the variable valve mechanism is applied to an intake valve will be described. However, the present invention can be applied to the exhaust valve in the same manner as the intake valve.

  First, the schematic configuration of the engine will be described with reference to FIGS.

  The engine 10 of this example is an in-line four-cylinder gasoline engine mounted on a vehicle, and includes a cylinder block 11 having four cylinders (cylinders: # 1 to # 4) 12 and a cylinder mounted on the cylinder block 11. And a head 14. A piston 13 is accommodated in each cylinder 12 in a state where the piston 13 can reciprocate. The piston 13 is connected to the crankshaft 34 via a connecting rod, and the reciprocating motion of the piston 13 is converted into the rotational motion of the crankshaft 34 by the connecting rod.

  The cylinder head 14 of the engine 10 is provided with a pair of intake ports 17 and exhaust ports 18 communicating with the combustion chambers 15 for each cylinder 12. In the combustion chamber 15, a spark plug 16 is arranged for each cylinder 12.

  An intake valve 21 that opens and closes each intake port 17 and an exhaust valve 22 that opens and closes each exhaust port 18 are disposed in the cylinder head 14. Each intake valve 21 is provided with a valve spring 21a, and each intake valve 21 is urged in a direction to close the intake port 17 by the elastic force of the valve spring 21a. Similarly, each exhaust valve 22 is provided with a valve spring 22a.

  Above the intake valve 21, an intake camshaft 23 having one intake cam 23a for each cylinder 12 is disposed. The intake camshaft 23 is rotatably supported by a plurality of support walls 25. The support wall 25 includes a cam housing that is provided integrally with the cylinder head 14 and a cam cap that is detachably attached to the cam housing by bolt fastening or the like.

  Further, an exhaust camshaft 24 having one exhaust cam 24 a for each cylinder 12 is disposed above the exhaust valve 22. The exhaust camshaft 24 is rotatably supported by a plurality of support walls 26. The support wall 26 includes a cam housing that is provided integrally with the cylinder head 14 and a cam cap that is detachably attached to the cam housing by bolt fastening or the like.

  The intake camshaft 23 and the exhaust camshaft 24 are drivingly connected to a crankshaft 34 via a timing chain 35 and the like. The rotation of the crankshaft 34 is transmitted to the intake camshaft 23 and the exhaust camshaft 24 via the timing chain 35 and the like, and the intake valve 21 and the exhaust valve 22 reciprocate by the rotation of the camshafts 23 and 24, respectively. .

  A rocker arm 27 having a roller 27a is swingably disposed between the upper end portion of the intake valve 21 and the intake cam 23a and between the upper end portion of the exhaust valve 22 and the exhaust cam 24a. Further, hydraulic lash adjusters 28 are arranged near the upper ends of the intake valve 21 and the exhaust valve 22, respectively. A compression reaction force of the valve spring 21a (22a) and a pushing force of the lash adjuster 28 are transmitted to the rocker arm 27. Thereby, the roller 27a of the rocker arm 27 is biased substantially upward. In this example, the roller 27a is in direct contact with each exhaust cam 24a, but indirectly with each intake cam 23a via a variable valve mechanism 30 described below. Are in contact. A rocker arm that does not include a roller may be used.

  In the engine 10 as described above, the variable valve mechanism 30 is provided in the vicinity of the intake camshaft 23. Hereinafter, the configuration of the variable valve mechanism 30 will be described in detail with reference to FIGS. 3 indicates a direction away from the actuator 33, and an arrow R indicates a direction approaching the actuator 33.

  The variable valve mechanism 30 is for continuously changing the operating angle and the maximum lift amount of the intake valve 21, and is disposed between the intake cam 23 a of the intake camshaft 23 and the rocker arm 27. . One end of the rocker arm 27 is supported by the lash adjuster 28, and the other end is in contact with the upper end of the intake valve 21.

  Here, as shown in FIG. 9, the operating angle of the intake valve 21 is an angle range from the valve opening timing IVO to the valve closing timing IVC of the intake valve 21 (expressed by a crank angle in FIG. 9). . The maximum lift amount of the intake valve 21 is the amount of movement of the intake valve 21 when the intake valve 21 is moved (lifted) to the lowest position within the movable range when the valve is opened. The operating angle and the maximum lift amount are changed in synchronization with each other by the variable valve mechanism 30. For example, the maximum lift amount decreases as the operating angle decreases. Further, as the operating angle decreases, the valve opening timing IVO and the valve closing timing IVC of the intake valve 21 approach each other, the valve opening period is shortened, and the intake air amount per cylinder is decreased.

  The variable valve mechanism 30 includes a variable valve lift mechanism 40 for each cylinder 12, and a rocker shaft (support shaft) 31, a control shaft (control shaft) 32, and an actuator common to all the variable valve lift mechanisms 40, respectively. 33 is provided.

  The rocker shaft 31 is a hollow cylindrical member extending along a direction parallel to the intake camshaft 23 (cylinder arrangement direction), and is provided on a plurality of support walls 25, 25,. It is attached in a state where movement in the axial direction and the circumferential direction is restricted. The rocker shaft 31 is formed with a long hole (through hole) 31a extending in the axial direction at a position sandwiched by a pair of support walls 25, 25 facing each other with the variable valve lift mechanism 40 interposed therebetween. A connect pin 44 is inserted through the long hole 31a. The direction in which the rocker shaft 31 extends is referred to as the “axial direction”.

  The control shaft 32 is a hollow cylindrical member in which an internal space 32 b extending in the axial direction is formed. The control shaft 32 is inserted into the rocker shaft 31 so as to be movable in the axial direction. An actuator 33 for driving the control shaft 32 is connected to one end side of the control shaft 32. The control shaft 32 is advanced and retracted in the axial direction (F direction or R direction) by the actuator 33. Further, the control shaft 32 is formed with a pair of pin insertion holes 32a and 32a for inserting the connect pins 44. The pair of pin insertion holes 32 a and 32 a are provided at positions different from each other by 180 degrees around the central axis of the control shaft 32.

  The inner diameter of the rocker shaft 31 is larger than the outer diameter of the control shaft 32, and an annular gap 52 is formed between the inner peripheral surface of the rocker shaft 31 and the outer peripheral surface of the control shaft 32. . As will be described later, the gap 52 is an oil passage through which lubricating oil flows. The internal space 32b of the control shaft 32 is also an oil passage through which lubricating oil flows, as will be described later.

  The number of variable valve lift mechanisms 40 is the same as the number of cylinders, and is externally mounted on the rocker shaft 31 so as to correspond to each cylinder 12. Each variable valve lift mechanism 40 includes a slider gear 43 that can move in conjunction with the control shaft 32, an input arm (cam hitting member) 41 that is driven by the intake cam 23 a of the intake cam shaft 23, and the intake valve 21. And an output arm (valve striking member) 42 for lifting. The input arm 41 and the output arm 42 are provided on the slider gear 43, and are disposed between a pair of support walls 25 and 25 that support the rocker shaft 31 (control shaft 32) in a state where movement in the axial direction is restricted. Has been. A plate-like shim 45 for adjusting the initial relative position of the input arm 41 and the output arm 42 in the axial direction with respect to the slider gear 43 is interposed between the output arm 42 and the support wall 25.

  The input arm 41 includes a cylindrical housing 41a. A helical spline 41b that meshes with an input-side helical spline 43a of a slider gear 43, which will be described later, is formed on the inner peripheral surface of the housing 41a. A pair of support pieces 41c and 41c protruding outward in the radial direction is provided on the outer periphery of the housing 41a, and a roller 41e is disposed between the pair of support pieces 41c and 41c. The roller 41e is rotatably supported by a rotation shaft 41d parallel to the rocker shaft 31.

  A pair of output arms 42 and 42 are disposed on both sides in the axial direction of the input arm 41. Each output arm 42 includes a cylindrical housing 42a. A helical spline 42b that meshes with the output-side helical spline 43b of the slider gear 43 is formed on the inner peripheral surface of the housing 42a. Further, a nose 42c is provided on the outer periphery of the housing 42a so as to protrude outward in the radial direction. The nose 42c is processed into a substantially triangular shape, and a cam surface 42d whose one side is curved in a concave shape.

  A slider gear 43 is disposed in an internal space defined by the input arm 41 and the two output arms 42 and 42. The slider gear 43 is externally mounted on the rocker shaft 31 so as to be movable in the axial direction in conjunction with the control shaft 32.

  The slider gear 43 is processed into a substantially cylindrical shape having a shaft insertion hole 43c at the center. An input-side helical spline 43 a that engages with the helical spline 41 b of the input arm 41 is machined in the central portion of the slider gear 43 in the axial direction. Further, output-side helical splines 43b that mesh with the helical splines 42b of the output arm 42 are respectively machined at both ends of the slider gear 43 in the axial direction. The output side helical spline 43b has a smaller outer diameter than the input side helical spline 43a. Further, the input side helical spline 43a and the output side helical spline 43b are processed so that the directions of twisting of teeth are opposite to each other.

  A circumferential groove 43 d extending in the circumferential direction is formed in the axial center of the inner wall of the slider gear 43. The circumferential groove 43d communicates with the outside of the slider gear 43 through a through hole 43e.

  The roller 41e of the input arm 41 is always pressed against the intake cam 23a by the elastic force of the lost motion spring 29 disposed in the cylinder head 14 in a compressed state. On the other hand, the roller 27a of the rocker arm 27 is pressed against the base circular portion of the housing 42a of the output arm 42 or the cam surface 42d of the nose 42c by the valve spring 21a of the intake valve 21. Thus, when the intake camshaft 23 rotates, the roller 41e of the input arm 41 is pushed down by the intake cam 23a. Then, the slider gear 43 and the output arm 42 are rocked together with the input arm 41. The intake valve 21 is lifted via the rocker arm 27 by such integral swinging of the input arm 41 and the output arm 42.

  Here, in order to connect the slider gear 43 outside the rocker shaft 31 to the control shaft 32 in the rocker shaft 31 so that power can be transmitted, a bush 46 having an arcuate cross section is formed in the circumferential groove 43d of the slider gear 43. It is arranged. A pin insertion hole (through hole) 46a is formed in the bush 46 at the middle in the circumferential direction.

  The bushing 46 is connected to the control shaft 32 via the connection pin 44. Specifically, one end portion of the connect pin 44 is inserted into the pin insertion hole 46 a of the bush 46, and the other end portion of the connect pin 44 is inserted into the pin insertion hole 32 a far from the bush 46 of the control shaft 32. . An intermediate portion of the connect pin 44 is inserted into the long hole 31 a of the rocker shaft 31 and the pin insertion hole 32 a on the side closer to the bush 46 of the control shaft 32. When the connect pin 44 and the bush 46 are assembled, the connect pin 44 includes two through holes 43e of the slider gear 43, a pin insertion hole 46a of the bush 46, a long hole 31a of the rocker shaft 31, and a control shaft 32. The slider gear 43 is inserted from the through hole 43e side in a state where the pin insertion holes 32a and 32a are aligned.

  In the variable valve mechanism 30, the slider gear 43 operates as follows.

  The control shaft 32 is movable in the axial direction with respect to the rocker shaft 31 within the range of the axial length of the long hole 31 a of the rocker shaft 31. Further, since the slider gear 43 is fixed in the axial position with respect to the control shaft 32 by the engagement of the circumferential groove 43d and the bush 46, when the control shaft 32 is moved in the axial direction by driving the actuator 33. The operation is transmitted to the slider gear 43 through the connect pin 44 and the bush 46. As a result, the slider gear 43 moves in the axial direction in conjunction with the control shaft 32. In addition, since the bush 46 is movable in the circumferential direction in the circumferential groove 43d of the slider gear 43, the slider gear 43 is rotatable with respect to the control shaft 32 within the range. Thus, when the control shaft 32 is moved in the axial direction, the slider gear 43 rotates with respect to the control shaft 32 while moving in the axial direction.

  When the torque of the intake camshaft 23 is transmitted to the input arm 41, the torque is transmitted from the input arm 41 to the output arm 42 via the slider gear 43. At this time, the slider gear 43 is connected to the rocker shaft. Oscillates around 31 (control shaft 32).

  In such a variable valve lift mechanism 40, the input side helical spline 43a of the slider gear 43 and the helical spline 41b of the input arm 41 are supported by being engaged with each other. Similarly, the output-side helical spline 43b of the slider gear 43 and the helical spline 42b of the output arm 42 are engaged with each other and supported.

  Therefore, by moving the slider gear 43 in the axial direction by moving the control shaft 32 forward and backward, the relative position in the axial direction between the slider gear 43 and the input arm 41 and the output arm 42 is changed. Twisting forces in opposite directions are applied to the output arm 42. As a result, the input arm 41 and the output arm 42 rotate relative to each other, and the relative phase difference between the input arm 41 (roller 41e) and the output arm 42 (nose 42c) is changed.

  As described above, when the relative phase difference between the roller 41e of the input arm 41 and the nose 42c of the output arm 42 is changed, the operating angle and the maximum lift amount of the intake valve 21 are changed. When the relative phase difference is the smallest (when the roller 41e and the nose 42c are closest to each other in the circumferential direction of the variable valve lift mechanism 40), the operating angle and the maximum lift amount of the intake valve 21 are the smallest. . On the contrary, when the relative phase difference is the largest (when the roller 41e and the nose 42c are in the most separated state in the circumferential direction of the variable valve lift mechanism 40), the working angle and the maximum lift amount of the intake valve 21 are the largest. Become.

  In the variable valve mechanism 30 of this example, the slider gear 43 for each cylinder 12 is provided on one common control shaft 32, so that the axial direction of the control shaft 32 by the drive of the actuator 33 is provided. The operating angle and the maximum lift amount of the intake valves 21 of all the cylinders 12 are changed at the same time in accordance with the advance / retreat.

  Next, the operation of the variable valve mechanism 30 will be described with reference to FIGS.

  First, the operation of the variable valve mechanism 30 when the control shaft 32 is moved in the direction away from the actuator 33 (the direction of arrow F in FIG. 3) will be described with reference to FIG.

  As shown in FIG. 10A, when the base circle portion of the intake cam 23a is in contact with the roller 41e of the input arm 41, the roller 27a of the rocker arm 27 is in contact with the base circle portion of the housing 42a of the output arm 42. In contact. Therefore, the intake valve 21 is maintained in a state where the maximum lift amount is “0” (a state where the intake port 17 of the engine 10 is closed).

  When the roller 41e of the input arm 41 is pushed down by the lift portion of the intake cam 23a along with the clockwise rotation of the intake cam shaft 23, the input arm 41 is counterclockwise with respect to the rocker shaft 31 (see FIG. It rotates in the direction of the arrow 10 (a). As a result, the output arm 42 and the slider gear 43 swing together.

  As a result, the cam surface 42d formed on the nose 42c of the output arm 42 contacts the roller 27a of the rocker arm 27, and the roller 27a is pushed down by the pressing of the cam surface 42d.

  As shown in FIG. 10B, when the roller 27a of the rocker arm 27 is pressed by the cam surface 42d, the rocker arm 27 swings about the contact portion with the lash adjuster 28, and the intake valve 21 opens. Is done.

  As described above, when the control shaft 32 moves to the maximum in the direction away from the actuator 33, the relative phase difference between the roller 41 e of the input arm 41 and the nose 42 c of the output arm 42 around the axis of the rocker shaft 31. Is the maximum.

  Thereby, when the intake cam 23a pushes down the roller 41e to the maximum, the rocking amount (swing range) of the rocker arm 27 becomes the largest, and the intake valve 21 is opened and closed with the maximum operating angle and the maximum lift amount.

  Next, with reference to FIG. 11, the operation of the variable valve mechanism 30 when the control shaft 32 is moved in the direction (arrow R direction in FIG. 3) that is as close as possible to the actuator 33 will be described.

  As shown in FIG. 11A, when the base circle portion of the intake cam 23a is in contact with the roller 41e of the input arm 41, the contact position between the output arm 42 and the roller 27a is maximized from the cam surface 42d. Is far away. When the roller 41e of the input arm 41 is pushed down by the lift portion of the intake cam 23a due to the rotation of the intake cam shaft 23, the input arm 41 and the output arm 42 rotate together.

  However, in this case, since the contact position between the output arm 42 and the roller 27a is farthest from the cam surface 42d, the output arm 42 until the pressing of the roller 27a of the rocker arm 27 by the cam surface 42d is started. The amount of rotation is larger than that shown in FIG. Further, when the roller 41e of the input arm 41 is pushed down by the lift portion of the intake cam 23a, the range of the cam surface 42d that comes into contact with the roller 27a is reduced to only a part of the base end side of the nose 42c. For this reason, the rocking | fluctuation amount (swinging range) of the rocker arm 27 according to depression of the roller 41e by the lift part of the intake cam 23a becomes small.

  As shown in FIG. 11B, when the rocking amount of the rocker arm 27 is small, the intake valve 21 is opened with a smaller maximum lift amount.

  Further, when the control shaft 32 moves to the maximum in the direction approaching the actuator 33, the relative phase difference between the roller 41e and the nose 42c around the axis of the rocker shaft 31 is minimized.

  Thereby, when the intake cam 23a pushes down the roller 41e to the maximum, the displacement amount of the roller 27a becomes the smallest, and the intake valve 21 is opened and closed with the minimum operating angle and the maximum lift amount.

  As described above, in the variable valve mechanism 30, when the control shaft 32 common to all the cylinders 12 is moved in the axial direction by driving the actuator 33, the slider gear 43 is moved in the axial direction. The relative position of the input arm 41 and the output arm 42 in the axial direction with respect to the slider gear 43 changes in each variable valve lift mechanism 40 in accordance with the axial movement position of the control shaft 32. As a result, the input arm 41 and the output arm 42 on the slider gear 43 are relatively rotated, the relative phase difference between the input arm 41 and the output arm 42 is changed, and the operating angle and the maximum lift amount of the intake valve 21 are continuously increased. Has been changed.

  In the variable valve mechanism 30 described above, lubricating oil is supplied to the sliding parts (including gear meshing parts) between the constituent parts, in particular, the constituent parts that move relative to each other in a state of being in contact with each other. I try to secure the movement. For this reason, the variable valve mechanism 30 is formed with an oil passage for supplying lubricating oil from the outside to the sliding portion between such components. Next, an oil passage for supplying lubricating oil to sliding portions between the components of the variable valve mechanism 30 will be described with reference to FIG.

  Specifically, the oil passage of the variable valve mechanism 30 is as follows. An oil supply path 51 provided in the support wall 25, an annular gap 52 between the inner peripheral surface of the rocker shaft 31 and the outer peripheral surface of the control shaft 32, the side wall portion 42f of the housing 42a of the output arm 42 and the rocker shaft 31 An annular gap 53 between the outer circumferential surface of the slider gear 43, an annular gap 54 between the inner circumferential surface of the slider gear 43 and the outer circumferential surface of the rocker shaft 31, an outer circumferential surface of the slider gear 43 and the inner circumference of the input arm 41. Clearance 55 (including a meshing portion between the input side helical spline 43a of the slider gear 43 and the helical spline 41b of the input arm 41), and a clearance 56 between the outer peripheral surface of the slider gear 43 and the inner peripheral surface of the output arm 42 ( Including a meshing portion between the output-side helical spline 43b of the slider gear 43 and the helical spline 42b of the output arm 42), A cylindrical space 57 between the end portion (end portion on the F direction side) of the shaft 31 and the end portion (end portion on the F direction side) of the control shaft 32, the outer peripheral surface of the rocker shaft 31, and the housing of the output arm 42 It is an annular space 58 between the inner peripheral surface of 42a. Also, a through hole 31 b provided in the rocker shaft 31, a through hole 31 c, the long hole 31 a, the internal space 32 b of the control shaft 32, the pin insertion hole 32 a, and a through hole 41 f provided in the housing 41 a of the input arm 41. (See FIG. 3), a through hole 42e provided in the housing 42a of the output arm 42, the circumferential groove 43d of the slider gear 43 (including the gap between the circumferential groove 43d and the bush 46), and the through hole 43e (see FIG. 8). ).

  The location where the lubricating oil is supplied through the oil passage of the variable valve mechanism 30 described above is a sliding portion between components that move relative to each other, and specifically, is the following location. These are between the rocker shaft 31 and the control shaft 32, between the rocker shaft 31 and the slider gear 43, between the slider gear 43 and the input / output arms 41 and 42, between the slider gear 43 and the bush 46, and the like.

  The oil supply path 51 of the support wall 25 and the gap 52 or the space 57 between the rocker shaft 31 and the control shaft 32 are communicated with each other through the through hole 31 b of the rocker shaft 31. The space 57 allows the gap 52 and the internal space 32 b of the control shaft 32 to communicate with each other. Further, the gap 52 between the rocker shaft 31 and the control shaft 32 and the gap 53 between the output arm 42 and the rocker shaft 31 are communicated with each other through the through hole 31 c of the rocker shaft 31. Further, the gap 52 and the internal space 32 b of the control shaft 32 are communicated with each other by a pin insertion hole 32 a of the control shaft 32. Further, the circumferential groove 43 d of the slider gear 43 and the gap 55 between the slider gear 43 and the input arm 41 are communicated with each other through the through hole 43 e of the slider gear 43.

  The oil supply passage 51 of the support wall 25 is an inflow port for lubricating oil. A part of the lubricating oil discharged from the oil pump flows into the oil passage of the variable valve mechanism 30 described above in the process of circulating each part of the engine 10 through the oil supply passage 51. Then, after flowing through the oil passage of the variable valve mechanism 30, the lubricating oil is discharged to the outside from the through hole 41 f of the input arm 41 or the through hole 42 e of the output arm 42.

  Furthermore, in this example, the oil supply path 51 is one of the support walls 25, 25 facing each other with the variable valve lift mechanism 40 interposed therebetween (the support wall 25 on the R direction side in FIG. 12), And it is provided in the support wall 25 (support wall 25 which supports the edge part of the F direction side of the rocker shaft 31) arrange | positioned at the side farthest from the actuator 33. Thus, by forming the oil supply path 51 in the support wall 25 disposed in the vicinity of the end of the control shaft 32, the lubricating oil can be smoothly supplied to the internal space 32b of the control shaft 32. An oil supply path 51 can be provided for each support wall 25.

  Then, the lubricating oil that has flowed into the oil supply path 51 of the support wall 25 disposed on the side farthest from the actuator 33 passes through the through hole 31 b of the rocker shaft 31 and flows into the space 57. The lubricating oil that has flowed into the space 57 is supplied to the sliding portion between the components that move relative to each other through the oil passage of the variable valve mechanism 30 via the gap 52 or the internal space 32 b of the control shaft 32. Thereby, the sliding part between the components of the variable valve mechanism 30 that move relative to each other is lubricated. On the other hand, the lubricating oil that has flowed into the oil supply path 51 of the other support wall 25 passes through the through hole 31 b of the rocker shaft 31 and flows into the gap 52. The lubricating oil that has flowed into the gap 52 moves between components that move relative to each other through the oil passage of the variable valve mechanism 30 through the long hole 31a, the through hole 31c of the rocker shaft 31, the pin insertion hole 32a of the control shaft 32, and the like. Supplied to the sliding portion. Thereby, the sliding part between the components of the variable valve mechanism 30 that move relative to each other is lubricated.

  In this example, as described above, the control shaft 32 is a hollow member, and the internal space 32 b is a part of the oil passage of the variable valve mechanism 30. Thereby, the following effects can be obtained.

  When the control shaft 32 is moved in the axial direction by driving the actuator 33 to change the valve characteristics (working angle and maximum lift amount) of the intake valve 21, the space between the rocker shaft 31 and the control shaft 32 is changed. Although the lubricating oil such as 57 can be a resistance, the resistance received from the lubricating oil can be reduced by using the hollow control shaft 32. Specifically, the cross-sectional area of the control shaft 32 when cut along a plane perpendicular to the axial direction is smaller than when the control shaft is solid rather than hollow. For this reason, compared with the case where a control shaft is solid, the resistance received from lubricating oil at the time of the movement of the control shaft 32 to an axial direction can be reduced. The smooth movement of the control shaft 32 can be ensured, and the operating angle and the maximum lift amount of the intake valve 21 can be changed quickly. Further, even if the control shaft 32 is moved against the resistance received from the lubricating oil, the power consumption of the actuator 33 can be saved and the influence on fuel consumption can be reduced as compared with the case where the control shaft is solid. be able to.

  Moreover, since the internal space 32b of the control shaft 32 forms a part of the oil passage of the variable valve mechanism 30, the sliding between the components that move relative to each other compared to the case where the control shaft is solid. Lubrication of the portion can be performed more effectively, and the degree of freedom in designing the lubrication path can be improved.

  Although the case where the control shaft 32 has a cylindrical shape has been described in the above example, the shape of the control shaft 32 is not limited to a cylindrical shape as long as it is hollow. For example, the control shaft may be formed in a square pipe shape.

It is sectional drawing which shows one Embodiment of the variable valve mechanism of the engine to which this invention is applied. It is a top view which shows the cylinder head of an engine. It is a perspective view which shows the input arm, output arm, etc. of a variable valve mechanism. It is a disassembled perspective view which shows the slider gear, input arm, output arm, etc. of a variable valve mechanism. It is a perspective view which shows the slider gear, rocker shaft, control shaft, etc. of a variable valve mechanism. It is a horizontal fracture perspective view showing a slider gear, an input arm, an output arm, etc. of a variable valve mechanism. It is sectional drawing which shows the assembly | attachment of the slider gear of a variable valve mechanism, a rocker shaft, a control shaft, a bush, and a connect pin. It is sectional drawing along the XX line of FIG. It is a figure which shows the working angle and lift amount of an intake valve which are changed by the variable valve mechanism. It is a side view used for explanation of operation of a variable valve mechanism when the relative phase difference between an input arm and an output arm is maximized. It is a side view used for explanation of operation of a variable valve mechanism when the relative phase difference between an input arm and an output arm is minimized. It is sectional drawing which shows the oil path inside a variable valve mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 14 Cylinder head 21 Intake valve 23 Intake cam shaft 23a Intake cam 25 Support wall 27 Rocker arm 30 Variable valve mechanism 31 Rocker shaft 31a Long hole 32 Control shaft 32a Pin insertion hole 32b Internal space 33 Actuator 40 Variable valve lift mechanism 41 Input Arm 42 Output arm 43 Slider gear 43c Shaft insertion hole 43d Circumferential groove 44 Connect pin 46 Bush 51 Oil supply path 52 Clearance 57 Space

Claims (1)

A hollow support shaft;
A control shaft disposed in the support shaft so as to be movable in the axial direction;
A variable valve lift mechanism disposed on the support shaft,
The variable valve lift mechanism includes a slider driven in the axial direction in conjunction with a control shaft, an input arm that engages with a helical spline formed on the outer peripheral surface of the slider and receives a force from a camshaft, An output arm that engages with a helical spline formed in a direction different from the helical spline that engages with the input arm on the outer peripheral surface of the slider and lifts the engine valve is provided,
In the variable valve mechanism of the internal combustion engine that changes the valve characteristics of the engine valve by moving the control shaft in the axial direction and supplies lubricating oil through an oil passage between components that move relative to each other.
A variable valve mechanism for an internal combustion engine, wherein the control shaft is hollow.

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