JP2008231945A - Variable valve train of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve train of an internal combustion engine, capable of locking the whole rocker shaft without individually providing locking parts when the rocker shaft is divided into partial rocker shafts. <P>SOLUTION: Relative rotation is prevented by engagement between the partial rocker shafts 70 to 76 forming the rocker shaft. The partial rocker shaft 70 in a #1 cylinder is locked with respect to the side of an internal combustion engine body by a rotation preventing pin 94. Therefore, all the partial rocker shafts 70-76 are prevented from being rotated around a shaft with respect to the internal combustion engine body, and the whole rocker shaft can be locked without individually providing the locking parts, in the variable valve train in which the rocker shaft is divided into the partial rocker shafts 70-76. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an internal combustion engine variable valve mechanism that adjusts a valve operating angle of an internal combustion engine by interlocking a valve operating angle adjusting member of a mediation drive mechanism with an axial movement of a control shaft disposed in the shaft of a rocker shaft. .

  A variable valve mechanism is known in which a mechanism provided on an internal combustion engine main body (including a cam carrier) is driven by the axial movement of a control shaft to vary the valve operating angle of an intake valve or an exhaust valve ( For example, see Patent Document 1). In such a variable valve mechanism, in order to swingably support a plurality of mediation drive mechanisms arranged in each cylinder, a rocker shaft having a control shaft disposed therein is inserted into the central axis position of the mediation drive mechanism. ing. As a result, when the valve is driven, the mediating drive mechanism swings while being supported by the rocker shaft.

  The rocker shaft is supported by wall portions (bearings) on the internal combustion engine main body side on both sides of the intermediate drive mechanism. The positional relationship between the mediation drive mechanisms is set by defining the axial position by the side surface on one side of the wall portion. By setting the axial position definition by this side face with high accuracy, the valve operating angle in each cylinder by the control shaft can be adjusted without causing variation among the cylinders.

  However, the internal combustion engine body may be formed of a material different from that of the rocker shaft and the control shaft in order to reduce weight and increase strength. For this reason, the difference between the coefficient of thermal expansion on the internal combustion engine body side and the coefficient of thermal expansion on the rocker shaft and control shaft side increases, and the positional relationship between the mediation drive mechanisms shifts with the temperature change of the internal combustion engine, resulting in high accuracy. It is difficult to maintain a proper positional relationship. As a result, there is a possibility that appropriate valve operating angle control cannot be performed as a whole internal combustion engine.

In order to solve such a problem, positioning of the intermediate drive mechanism is performed with reference to the rocker shaft, so that it is not affected by the difference in thermal expansion coefficient between the internal combustion engine main body side and the rocker shaft and the control shaft. A variable valve mechanism has been proposed (see, for example, Patent Documents 2 and 3).
Japanese Patent Laid-Open No. 2001-263015 (page 7-8, FIG. 5-20) JP 2006-17114 A (page 5-7, FIGS. 3 and 4) JP 2006-63845 A (page 8-9, FIG. 3-5)

  In such a rocker shaft, if one rocker shaft shared by all cylinders is used, the assembly workability of the variable valve mechanism is not good. For this reason, a method of arranging a plurality of partial rocker shafts formed separately for each cylinder group composed of one or more cylinders in the axial direction is conceivable. As a result, it is only necessary to assemble each cylinder group and combine them together with the control shaft on the internal combustion engine without handling a single long rocker shaft, so that the assembly workability of the variable valve mechanism is improved.

  However, when the rocker shaft is divided in this manner, the intermediate drive mechanism swings on the rocker shaft during operation of the internal combustion engine, so that a rotational force around the axis is generated in each partial rocker shaft. When the rotational force around the axis is generated in this way, there is a risk of hindering the operation of the mechanism that connects the internal control shaft and the intermediate drive mechanism of the outer peripheral portion. Specifically, the frictional force between the pin extending from the control shaft to the mediation drive mechanism and the long hole of the rocker shaft may increase, and the smooth adjustment of the valve operating angle by the mediation drive mechanism may be hindered.

  If a single rocker shaft is used as in the prior art, the rotation of the entire rocker shaft can be stopped by forming a locking portion for preventing rotation on the internal combustion engine body at one end of the rocker shaft. However, if the rocker shaft is divided into partial rocker shafts as described above, the locking portions must be provided to prevent rotation of the individual partial rocker shafts. Space is limited on the internal combustion engine, and thus it may be difficult to form a locking portion for each partial rocker shaft.

  An object of the present invention is to provide an internal combustion engine variable valve mechanism that can prevent rotation of the entire rocker shaft without providing individual locking portions when the rocker shaft is divided into partial rocker shafts.

In the following, means for achieving the above object and its effects are described.
The internal combustion engine variable valve mechanism according to claim 1 is an intermediate drive mechanism that mediates the lift driving force of the valve cam of the internal combustion engine to the valve side by being supported by the rocker shaft and swinging about the axis of the rocker shaft. Provided for each cylinder and adjusts the valve operating angle in each cylinder of the internal combustion engine by interlocking the valve operating angle adjusting member of the mediation drive mechanism by the axial movement of the control shaft arranged in the shaft of the rocker shaft A plurality of partial rocker shafts that are formed separately for each cylinder group composed of one or more cylinders of an internal combustion engine and arranged adjacent to each other in the axial direction. Are brought into a single rocker shaft, and one rocker shaft in the arrangement of the partial rocker shafts. The rotation of the partial rocker shaft is prevented from rotating around the axis with respect to the internal combustion engine body, and the relative rotation about the axis between the partial rocker shafts is achieved by engaging between the adjacent partial rocker shafts. Is characterized by being blocked.

  Thus, relative rotation is prevented between the partial rocker shafts by the engagement between the partial rocker shafts. Accordingly, one partial rocker shaft in the array is prevented from rotating about the axis with respect to the internal combustion engine body side, so that all partial rocker shafts rotate about the axis with respect to the internal combustion engine body side. Will be blocked. Therefore, in the internal combustion engine variable valve mechanism according to the present invention, it is possible to prevent the entire rocker shaft from rotating without providing a locking portion on each rocker shaft of the rocker shaft.

  According to a second aspect of the present invention, there is provided the variable valve mechanism for the internal combustion engine according to the first aspect, wherein the partial rocker shaft that is prevented from rotating about the axis relative to the internal combustion engine body side is one of the arrangements of the partial rocker shafts. It is the partial rocker shaft arrange | positioned at the terminal, It is characterized by the above-mentioned.

  Thus, even if the partial rocker shaft arranged at one end of the array is prevented from rotating about the axis with respect to the internal combustion engine main body, the entire rocker shaft can be prevented from rotating.

  An internal combustion engine variable valve mechanism according to claim 3 is characterized in that, in claim 2, an actuator for driving the control shaft in the axial direction is arranged on the other end side of the arrangement of the partial rocker shafts. And

  In this way, the rotation may be prevented with respect to the partial rocker shaft at one end of the array, and the actuator may be driven in the axial direction by the actuator from the partial rocker shaft side at the other end of the array. Thus, the freedom degree of arrangement | positioning with an actuator and a rotation stopper is high.

  In the internal combustion engine variable valve mechanism according to claim 4, in any one of claims 1 to 3, a step is formed on the end surfaces of the adjacent partial rocker shafts, whereby the partial rocker shafts are axially connected. It is characterized by being engaged around.

Thus, the partial rocker shafts can be engaged with each other around the axis with a simple configuration by the step of the end face. For this reason, formation of a partial rocker shaft is also easy.
The internal combustion engine variable valve mechanism according to claim 5 is the internal combustion engine variable valve mechanism according to any one of claims 1 to 4, wherein the tip portion rocker shaft at the tip in the axial force direction generated in the intermediate drive mechanism by a reaction force from the valve side. The position of the entire rocker shaft in the axial direction is determined with the axial position as a reference position, and an axial force receiving portion for receiving an axial force generated in the intermediate drive mechanism is formed at least in each partial rocker shaft other than the tip partial rocker shaft It is characterized by being.

  In this rocker shaft, an axial force receiving portion that receives an axial force generated in the intermediate drive mechanism is formed at least on each partial rocker shaft other than the tip partial rocker shaft. Therefore, the intermediary drive mechanism supported by the partial rocker shaft other than the tip partial rocker shaft can set the positional relationship on the rocker shaft with high accuracy without being affected by the difference in thermal expansion from the internal combustion engine body side. It is possible to maintain the positional relationship with the mediation drive mechanism supported by the tip portion rocker shaft with high accuracy.

  In such an internal combustion engine variable valve mechanism using an intermediary drive mechanism, the rocker shaft is divided into partial rocker shafts, so that the manufacture becomes easy. You can stop.

  The internal combustion engine variable valve mechanism according to claim 6, wherein the cylinder is fixed to the partial rocker shaft on the front side in the axial direction in the contact portion between the partial rocker shafts. In addition, since the part of the cylindrical body and the part of the partial rocker shaft on the rear side in the axial force direction are engaged about the axis, relative rotation about the axis between the partial rocker shafts is prevented. It is characterized by.

  The cylindrical body fixed to the partial rocker shaft on the front side in the axial force direction enhances the integrity with the adjacent partial rocker shaft, and the rocker shaft formed by arranging these partial rocker shafts can also enhance the integrity. .

  Then, by utilizing a part of the cylindrical body to engage with a part of the partial rocker shaft, relative rotation around the axis is prevented between adjacent partial rocker shafts. This makes it possible to prevent the entire rocker shaft from rotating.

  The internal combustion engine variable valve mechanism according to claim 7, wherein a part of the partial rocker shaft on the rear side in the axial force direction that engages with a part of the cylindrical body is the axial force receiving portion. It is characterized by being.

  A part of the partial rocker shaft that engages with a part of the cylindrical body can be an axial force receiving portion. This makes it possible to easily establish a reliable engagement state between the partial rocker shafts.

  An internal combustion engine variable valve mechanism according to an eighth aspect of the present invention is the internal combustion engine variable valve mechanism according to the seventh aspect, wherein a part of the cylindrical body is disposed between the intermediate drive mechanism and the axial force receiving portion together with the axial force receiving portion. By engaging with the shim, the rotation of the shim around its axis is suppressed.

  As described above, since a part of the cylindrical body can suppress the rotation of the shim, the shim can be prevented from falling off with a small number of parts.

[Embodiment 1]
1 and 2 show the configuration of a variable valve mechanism 4 in a multi-cylinder internal combustion engine (here, an in-line four-cylinder gasoline engine: hereinafter abbreviated as “engine”) 2 to which the above-described invention is applied. FIG. 1 shows a longitudinal section of one cylinder. FIG. 2 is a plan view mainly illustrating the configuration on the cam carrier 6 in the upper configuration of the engine 2. The cam carrier 6 may not be present, and the variable valve mechanism 4 may be configured directly on the cylinder head.

  The engine 2 of the present embodiment is for a vehicle and includes a cylinder block 8, a piston 10, and a cylinder head 12 attached on the cylinder block 8. Among these, the cylinder block 8 and the cylinder head 12 are formed of an aluminum alloy material.

  In the cylinder block 8, a plurality of cylinders, in this embodiment, four cylinders 2a (# 1 cylinder), 2b (# 2 cylinder), 2c (# 3 cylinder), 2d (# 4 cylinder) are formed in series. In each of the cylinders 2a to 2d, a combustion chamber 14 defined by a cylinder block 8, a piston 10 and a cylinder head 12 is formed. The number of cylinders may be 1 to 3, and may be 5 or more.

  In each of the cylinders 2a to 2d, four valves of two intake valves 16 and two exhaust valves 18 are arranged. The intake valve 16 opens and closes the intake port 20, and the exhaust valve 18 opens and closes the exhaust port 22. All the intake ports 20 are connected to the surge tank via the intake manifold, and distribute the air supplied from the surge tank side to the cylinders 2a to 2d. A fuel injector is disposed in each intake port 20 or intake manifold so as to inject fuel into the intake port 20 of each cylinder 2a to 2d. In addition to the configuration in which fuel is injected on the upstream side of the intake valve 16 as described above, a direct injection gasoline engine that directly injects fuel into each combustion chamber 14 can also be used.

  The engine 2 of the present embodiment can adjust the intake air amount by changing the valve operating angle of the intake valve 16. However, since the maximum valve lift is also changing at the same time, the description of the valve operating angle will also be the description of the maximum valve lift.

  A throttle valve is disposed in the intake passage upstream of the surge tank. The throttle valve is normally fully opened when the intake air amount is adjusted by adjusting the valve operating angle of the intake valve 16. As the throttle valve opening control, for example, the throttle valve is fully opened when the engine 2 is started, and the throttle valve is fully closed when the engine 2 is stopped. If the valve operating angle of the intake valve 16 cannot be adjusted for some reason, or if the intake air amount cannot be adjusted sufficiently by adjusting the valve operating angle of the intake valve 16, the throttle valve opening The intake air amount is controlled by the control.

  The lift drive of the intake valve 16 is driven by a valve of an intake cam 30 provided on the intake camshaft 28 via an intermediate drive mechanism 24 (corresponding to a valve characteristic adjusting mechanism) disposed on the cylinder head 12 and a roller rocker arm 26. This is made possible by the transmission of force. In this valve driving force transmission, the valve operating angle of the intake valve 16 is adjusted by adjusting the transmission state by the mediation drive mechanism 24 by the function of the slide type actuator 32. The intake camshaft 28 is linked to the rotation of the crankshaft 38 of the engine 2 via a timing sprocket provided in a valve timing variable mechanism 34 disposed at one end and a timing chain 36.

  The exhaust valves 18 of the cylinders 2a to 2d are opened and closed at a constant valve operating angle via a roller rocker arm 44 by an exhaust cam 42 provided on an exhaust camshaft 40 that rotates in conjunction with the rotation of the engine 2. Yes. The exhaust camshaft 40 is interlocked with the rotation of the crankshaft 38 of the engine 2 via a timing sprocket and a timing chain 36 provided in a variable valve timing mechanism 46 disposed at one end. The exhaust ports 22 of the cylinders 2a to 2d are connected to an exhaust manifold, and exhaust is discharged to the outside through a purification catalytic converter.

  The intake camshaft 28, the exhaust camshaft 40, the actuator 32, the intermediate drive mechanism 24, and the variable valve timing mechanisms 34 and 46 described above are integrated into the cam carrier 6.

  The cam carrier 6 is attached to the cylinder head 12 to form a part of the engine body. The cam carrier 6 includes a front side wall 48, a rear side wall 50, and two lateral side walls 52, 54. It is integrally formed in a rectangle corresponding to the upper surface outer peripheral shape. In the internal space surrounded by the side walls 48, 50, 52, 54, four bearings 56, 58, 60, 62 are arranged in parallel so as to communicate between the side walls 52, 54, and the side walls 48- 54 is integrally formed. Since the front side wall 48 also serves as a bearing, it is also referred to as a bearing 48 hereinafter. The cam carrier 6 is integrally formed of an aluminum alloy material in the same manner as the cylinder block 8 and the main body of the cylinder head 12.

  The bearings 48 and 56 to 62 support the intake camshaft 28 and the exhaust camshaft 40 so as to be rotatable in parallel. Further, four intermediary drive mechanisms 24 provided for each cylinder are arranged between the intake camshaft 28 and the lateral side wall 52. The arrangement state of these mediation drive mechanisms 24 is as shown in FIGS. 3A is a front view, FIG. 4B is a right side view, FIG. 4 is a perspective view, FIG. 5 is a perspective view in a face-up state, FIG. 6 is an exploded perspective view, and FIGS. It is the expansion perspective view which isolate | separated and showed the mediation drive mechanism 24 part in # 2 cylinder 2a, 2b.

  Here, each mediation drive mechanism 24 is supported by a rocker shaft 68 sandwiched between bearings 48, 56 to 62 and caps 48a, 56a, 58a, 60a, 62a. Further, a control shaft 80 is disposed through the rocker shaft 68 in the axial direction. As for the control shaft 80, one common to all the mediation drive mechanisms 24 is used, but for the rocker shaft 68, partial rocker shafts 70, 72, 74, 76 divided in the axial direction for each cylinder 2a to 2d are provided. They are arranged in a contact state in the axial direction.

  Shims 82 and 84 are arranged on both sides of each mediation drive mechanism 24. Among these, the shim 82 arranged on the left side of each mediation drive mechanism 24 shown in FIG. 3A adjusts the axial arrangement of each mediation drive mechanism 24, and the shim 84 on the opposite side has the remaining shim 84. Filling the space.

  A cap-shaped tip bush 78 is provided in contact with the shim 82 of the # 4 cylinder 2d on the actuator 32 (FIG. 2) side. The tip bush 78 has a partial rocker belonging to the # 4 cylinder 2d. One end of the shaft 76 is inserted and supported. As shown in FIG. 11, the front end bush 78 has three mediating drives of # 1, # 2, and # 3 cylinders 2a to 2c, as will be described later, by contacting the end surface of the partial rocker shaft 76 to the inner bottom surface 78a. The axial force generated in the mechanism 24 is received. The intermediary drive mechanism 24 of the # 4 cylinder 2d receives an axial force via a shim 82 at the flange portion 78c of the tip bush 78. The control shaft 80 is movable in the axial direction through a through hole 78b formed in the inner bottom surface 78a of the tip bush 78.

  Thus, the tip bush 78 receiving the axial force generated in the mediation drive mechanism 24 of all the cylinders 2a to 2d is brought into contact with the bearing 62 and the cap 62a (FIG. 2) at the flange portion 78c. Is applied to one position on the cam carrier 6 side (side surface of the bearing 62 and the cap 62a). Accordingly, with the side surfaces of the bearing 62 and the cap 62a as the reference position, the intermediate drive mechanism 24 of the # 4 cylinder 2d is connected to the three intermediate drive mechanisms # 1, # 2, and # 3 cylinders 2a to 2c via the tip bush 78. 24, the axial position is determined via the partial rocker shafts 70-76.

  The intermediate drive mechanism 24, the partial rocker shafts 70 to 76, the control shaft 80, the shims 82 and 84, and the tip bush 78 are made of a high-strength material, here, an iron-based material.

  The configurations of the rocker shaft 68 and the control shaft 80 are shown in FIGS. 9A is a perspective view showing a combined state of the rocker shaft 68, the control shaft 80, the tip bush 78, and the rotation prevention pin 94, FIG. 9B is a front view thereof, and FIG. 9C is a plan view thereof. FIG. 10 is an exploded perspective view showing the rocker shaft 68, the control shaft 80, the tip bush 78 and the rotation prevention pin 94.

  Each of the partial rocker shafts 70 to 76 is formed with an elongated hole 70a, 72a, 74a, 76a in the axial direction near the center. Pins 86, 88, 90, and 92 are disposed on the control shaft 80 through the long holes 70 a to 76 a. An insertion hole is formed in the control shaft 80 in the direction perpendicular to the axis for each of the pins 86 to 92, and the base ends of the pins 86 to 92 are inserted to support the pins 86 to 92 as shown. is doing.

  Steps (concave portions 70d, 72d, 74d, convex portions 72f, 74f, 76f) are formed on the respective end surfaces that are the contact portions between the partial rocker shafts 70 to 76. In the state where the partial rocker shafts 70 to 76 are arranged as the rocker shaft 68, the stepped portions 74 f are fitted into the concave portions 72 d as shown in FIG. 11, and the contact surfaces 72 e that are the end surfaces of the partial rocker shafts 72 and 74. 74e are in contact with each other. Even if one partial rocker shaft 72 attempts to rotate relative to the other partial rocker shaft 74 around the axis, the side surface of the convex portion 74f and the side surface of the concave portion 72d are brought into contact with each other to engage in rotation in the circumferential direction. Therefore, relative rotation is prevented.

  FIG. 11 shows an engaged state between the partial rocker shaft 72 of the # 2 cylinder 2b and the partial rocker shaft 74 of the # 3 cylinder 2c. This engagement state is between the partial rocker shaft 70 of the # 1 cylinder 2a and the partial rocker shaft 72 of the # 2 cylinder 2b, and the partial rocker shaft 74 of the # 3 cylinder 2c and the partial rocker shaft 76 of the # 4 cylinder 2d. The same applies to That is, the convex portions 72f and 76f are fitted into the concave portions 70d and 74d, and the partial rocker shafts 70 and 72 or the partial rocker shafts 74 and 76 are engaged in rotation in the circumferential direction, and relative rotation is prevented.

  Further, in the partial rocker shaft 70 of the # 1 cylinder 2a, on the side opposite to the side in contact with the partial rocker shaft 72 of the # 2 cylinder 2b, an axially long hole 70e that reaches the central sliding hole 70b at the end. Is formed. When the partial rocker shaft 70 is disposed on the cam carrier 6 in the long hole 70e, the tip of the anti-rotation pin 94 whose base is fixed to the bearing 48 side is inserted.

  Accordingly, the partial rocker shaft 70 is prevented from rotating about the axis with respect to the cam carrier 6 via the rotation prevention pin 94. Further, as described above, the relative rocker shafts 70 to 76 of all the cylinders 2a to 2d are prevented from rotating relative to each other. Accordingly, any of the partial rocker shafts 70 to 76 is prevented from rotating around the axis with respect to the cam carrier 6.

  The four pins 86 to 92 provided on the control shaft 80 protrude from the outer ends of the long holes 70a to 76a. The tips of the pins 86 to 92 are engaged with slider gears 106 (FIGS. 12 and 13), which will be described later, which are valve operating angle adjusting members of the respective mediating drive mechanisms 24. As a result, when one control shaft 80 arranged in the center sliding holes 70b, 72b, 74b, 76b formed in the axial direction inside each of the partial rocker shafts 70 to 76 moves in the axial direction, it is interlocked. Thus, the four slider gears in all the intermediary drive mechanisms 24 move simultaneously in the axial direction. In this way, the valve operating angles of the four cylinders 2a to 2d can be continuously adjusted by the variable valve mechanism 4. A locking flange 80a having a large diameter is integrally formed at the tip of the control shaft 80. By connecting the engaging portion of the actuator 32 to the locking flange 80a, the axial force generated in the slider gear by driving the actuator 32 (in the direction opposite to the axial force of the mediating drive mechanism 24) is generated. In contrast, it can be pulled to the # 4 cylinder 2d side, or can be returned to the # 1 cylinder 2a side by utilizing the axial force.

  The three partial rocker shafts 70 to 74 in the # 1 cylinder 2a to # 3 cylinder 2c are respectively provided with flange-shaped axial force receiving portions 70c, 72c, and 74c in the vicinity of the tip side, that is, the side close to the # 4 cylinder 2d. Yes. The axial force receiving portions 70c, 72c, and 74c receive the axial force from the mediation drive mechanisms 24 through the shims 82, respectively. The partial rocker shafts 70 to 74 in the # 1 cylinder 2a to # 3 cylinder 2c are in contact with each other at the axial end face. Further, among these, the partial rocker shaft 74 of the # 3 cylinder 2c and the partial rocker shaft 76 of the # 4 cylinder 2d are also in contact with each other at the end face in the axial direction. Therefore, the axial force generated in the three intermediate drive mechanisms 24 of the # 1 cylinder 2a to # 3 cylinder 2c by the reaction force of the intake valve 16 generated by the valve spring 16a (FIG. 1) is the partial rocker shaft 74 of the # 3 cylinder 2c. To the partial rocker shaft 76 of the # 4 cylinder 2d. The tip portion of the partial rocker shaft 76 of the # 4 cylinder 2d is inserted into the inner space of the tip bush 78 and is in contact with the inner bottom surface 78a which is an axial contact surface. The axial force generated in the three mediating drive mechanisms 24 of the three cylinders 2c is transmitted to the tip bush 78. Further, an axial force is applied to the bearing 62 and the cap 62a side via the flange portion 78c of the tip bush 78.

  Accordingly, the axial force of the mediation drive mechanism 24 caused by the reaction force received by the mediation drive mechanism 24 from the valve spring 16a of the intake valve 16 when the intake valves 16 of the cylinders 2a to 2d are driven is all bearing 62 and cap 62a. Will be given to the side.

  For this reason, the intermediate drive mechanism 24 in the # 1 cylinder 2a to # 3 cylinder 2c is not connected to the adjacent bearings 56 to 60 and caps 56a to 60a but via the partial rocker shafts 70 to 74, whereby the intermediate drive of the # 4 cylinder 2d is performed. The axial position is determined by the same bearing 62 and cap 62a as the mechanism 24. Therefore, the side surfaces of the cap 62a and the bearing 62 serve as a positioning reference via the rocker shaft 68, and no displacement occurs due to the difference in thermal expansion coefficient between the intermediate drive mechanism 24 of the four cylinders 2a to 2d and the control shaft 80.

  The configuration of the intermediate drive mechanism 24 in which the slider gear 106 is incorporated is as shown in the partially broken perspective views of FIGS. 12A is a partially broken perspective view of the front side of the intermediate drive mechanism 24, FIG. 12B is a partially broken perspective view of the back side, and FIG. 13 is a partially broken perspective view further reaching the inside of the slider gear 106. .

  The mediation drive mechanism 24 is provided with an input unit 100 provided in the center, a first swing cam 102 provided on one end side of the input unit 100, and an input unit 100 sandwiched between the first swing cam 102 and the opposite side. The second rocking cam 104 and the slider gear 106 disposed therein are provided.

  The pins 86 to 92 attached to the control shaft 80 pass through the long holes 70 a to 76 a formed in the partial rocker shafts 70 to 76 as described above, and the tips are locked to the slider gear 106. As a result, the slider gear 106 can swing with respect to the control shaft 80, but interlocks with the axial movement.

  The slider gear 106 has three helical spline portions 106a, 106b, and 106c. The central helical spline portion 106a meshes with the helical spline inside the input portion 100, and the helical spline portions 106b and 106c on both sides mesh with the helical splines inside the swing cams 102 and 104 (corresponding to the output portion), respectively.

  The helical spline at the input unit 100 and the helical spline at the swing cams 102 and 104 have different torsion angles. Here, the twist direction is reversed. As a result, when the actuator 32 moves the control shaft 80 in the direction of pulling out from the rocker shaft 68 against the axial force (H direction in FIG. 12), the roller 100d of the input unit 100 is driven by the cams of the swing cams 102 and 104. Relatively swings in a direction away from the portions 102d and 104d. On the other hand, when the control shaft 80 is moved back into the rocker shaft 68 using the axial force (L direction in FIG. 12), the roller 100d of the input unit 100 is moved to the cam portions 102d and 104d of the swing cams 102 and 104. Relatively swings in the approaching direction.

  Therefore, by moving the control shaft 80 in the direction of pulling out from the rocker shaft 68 (H direction in FIG. 12), the valve operating angle is changed from (C) to (B) and (A) in the valve lift patterns C1 and C2 shown in FIG. ) Can be continuously increased. Conversely, by moving the control shaft 80 back in the rocker shaft 68 (L direction in FIG. 12), the valve operating angle is continuously changed from (A) to (B) and (C) in FIG. Can be small.

According to the first embodiment described above, the following effects can be obtained.
(I). Relative rotation is prevented between the partial rocker shafts 70 to 76 constituting the rocker shaft 68 by the engagement between the partial rocker shafts 70 to 76. One partial rocker shaft in the array, here, the partial rocker shaft 70 in the # 1 cylinder 2a is prevented from rotating about the axis with respect to the cam carrier 6 on the internal combustion engine main body side. Accordingly, all the partial rocker shafts 70 to 76 are prevented from rotating around the axis with respect to the internal combustion engine main body. In this way, in the variable valve mechanism 4 configured by dividing the rocker shaft 68 into the partial rocker shafts 70 to 76, the entire rocker shaft 68 can be prevented from rotating without providing the individual locking portions.

  (B). The rotation of the rocker shaft 68 as a whole is prevented by a rotation prevention pin 94 inserted into the long hole 70e of the partial rocker shaft 70 on one end side (# 1 cylinder 2a side) of the arrangement of the partial rocker shafts 70 to 76. Yes. The control shaft 80 is driven in the axial direction by the actuator 32 from the side of the partial rocker shaft 76 on the other end side (# 4 cylinder 2d side) of the array. Thus, even if the anti-rotation mechanism (anti-rotation pin 94 and long hole 70e) and actuator 32 are arranged, the control shaft 80 can be moved in the axial direction and the rocker shaft 68 as a whole can be sufficiently prevented from rotating. Thus, the degree of freedom of arrangement of the actuator 32 and the rotation prevention mechanism (the rotation prevention pin 94 and the long hole 70e) is high.

  (C). The engagement between the partial rocker shafts 70 to 76 about the axis is made by steps (concave portions 70d, 72d, 74d, convex portions 72f, 74f, 76f) at the respective end surfaces that come into contact. Since it is possible to engage the shaft around such a simple configuration, it is easy to form the partial rocker shafts 70 to 76.

[Embodiment 2]
The arrangement state of the mediation drive mechanism 224 in the variable valve mechanism of the present embodiment is shown in FIGS. FIG. 15 is a front view, and FIG. 16 is a perspective view looking up. The mediation drive mechanism 224 has the same configuration as the mediation drive mechanism of the first embodiment. The first embodiment also applies to the tip bush 278, the control shaft 280, the shims 282, 284, the rotation prevention pins 294, the cam carrier bearings 248, 256, 258, 260, 262 and the caps 248a, 256a, 258a, 260a, 262a. It is the same composition as.

  17 and 18, the contact portion between the partial rocker shafts 270 to 276 constituting the rocker shaft 268 and the end of the partial rocker shaft 270 are connected to the cam carrier bearings 248 to 248 through the tubular bushes 234 to 240, respectively. 260 and the caps 248a to 260a. The point that the end of the partial rocker shaft 276 is sandwiched and supported by the cam carrier bearing 262 and the cap 262a via the tip bush 278 is the same as in the first embodiment. 17A is a partial vertical cross-sectional view showing a state in which the mediation drive mechanism 224 is disposed, and FIG. 17B is a partial vertical cross-sectional view showing the mediation drive mechanism 224 removed. FIG. 18 is an exploded perspective view.

  As shown in the perspective views of FIGS. 19 and 20, the tubular bushes 236 to 240 at the contact portion are fixed and integrated with the partial rocker shafts 272 to 276 on the front side in the axial force direction. The entire tubular bush 234 at the end is integrated by being fixed to the rear side in the axial force direction of the partial rocker shaft 270 by press-fitting. FIG. 19 is a perspective view, and FIG. 20 is a perspective view ascending.

  Further, as shown in the drawing, with respect to the tubular bushes 236 to 240 arranged at the contact portions between the partial rocker shafts 270 to 276, the engagement protrusions 236a, 238a, 240a protrude in the axial direction on the rear side in the axial force direction. Is provided. The tubular bush 234 provided in the # 1 cylinder partial rocker shaft 270 that is not disposed in the abutting portion has a long hole 270e integrated with the partial rocker shaft 270 side. Since the tip of the rotation prevention pin 294 fixed to the bearing 248 on the cam carrier side is inserted into the long hole 270e, rotation around the axis of the partial rocker shaft 270 of the # 1 cylinder can be prevented.

  The axial force receiving portions 270c, 272c, and 274c are formed in a ring shape on the peripheral surfaces of the partial rocker shafts 270 to 274, but notches 270d, 272d, and 274d are formed in part.

  In the first, second, and third cylinder partial rocker shafts 270 to 274, the front side in the axial direction is fitted by being inserted into the tubular bushes 236 to 240 when the variable valve mechanism is assembled on the cam carrier. . As a result, the respective contact surfaces 270a, 272a, 274a are brought into contact with the end surfaces on the rear side in the axial direction of the partial rocker shafts 272-276 of the # 2, 3, 4 cylinders in the tubular bushes 236-240. At this time, the engagement protrusions 236a to 240a of the tubular bushes 236 to 240 fixed to the # 2, 3, and 4 cylinder partial rocker shafts 272 to 276 are formed as shown in FIG. It arrange | positions in the space with respect to the notch parts 270d-274d of the axial force receiving parts 270c-274c of the shafts 270-274. FIG. 21 shows the relationship between the # 2 cylinder and the # 3 cylinder, but the relationship between the # 1 cylinder and the # 2 cylinder and the relationship between the # 3 cylinder and the # 4 cylinder are the same.

  Therefore, between the partial rocker shafts 270 to 276, the engaging protrusions 236a to 240a and the notches 270d to 274d are engaged, so that relative rotation is prevented. The distal partial rocker shaft 270 is prevented from rotating about its axis with respect to the cam carrier via an anti-rotation pin 294. For this reason, the rocker shaft 268 is prevented from rotating around the axis with respect to the cam carrier.

  In the present embodiment, the protruding length of the engaging projections 236a to 240a formed on the tubular bushes 236 to 240 exceeds the thickness of the axial force receiving portions 270c to 274c. For this reason, the tip is inserted into the inner space 282a of the shim 282 in which the axial position of the mediation drive mechanism 224 is set with high accuracy.

According to the second embodiment described above, the following effects can be obtained.
(I). When the tubular bushes 236 to 240 are used, relative rotation is prevented by the engagement between the partial rocker shafts 270 to 276 by the configuration as described above, and the cam carrier 6 is further pivoted by one partial rocker shaft 270. There is an anti-rotation around. Therefore, the tubular bushes 236 to 240 enhance the integrity of the rocker shaft 268 and prevent the rotation of the partial rocker shafts 270 to 276 about the axis with respect to the internal combustion engine main body side. In this way, even when the rocker shaft 268 is divided into the partial rocker shafts 270 to 276, the entire rocker shaft 268 can be prevented from rotating without providing the individual locking portions.

  (B). As part of the partial rocker shafts 270 to 274 engaged with a part of the tubular bushes 236 to 240 (engagement protrusions 236a to 240a) which are cylindrical bodies, axial force receiving parts 270c to 270c to 270d formed with notches 270d to 274d. 274c. For this reason, a reliable engagement state can be configured easily.

  (C). The engagement protrusions 236a to 240a also serve to suppress the rotation of the shim 282 for adjusting the axial position of the mediation drive mechanism 224 on the distal end side. Therefore, the effect of preventing the shim 282 from falling off can be obtained with a small number of parts.

(D). The effect (b) of the first embodiment is produced.
[Embodiment 3]
The support structure of the mediation drive mechanism 324 of this embodiment is as shown in the perspective view (upward view) of FIG. The # 1 cylinder partial rocker shaft 370 and the # 2 cylinder partial rocker shaft 372 of the present embodiment are the same as the # 1 cylinder partial rocker shaft 70 and # 2 cylinder of the first embodiment (FIGS. 6 to 8). Each of the partial rocker shafts 72 has the same shape. That is, the # 1 cylinder partial rocker shaft 370 has a recess 370d and an axial force receiving portion 370c on the front side in the axial force direction, and a long hole 370e on the rear side in the axial force direction. The # 2 cylinder partial rocker shaft 372 has a concave portion 372d and an axial force receiving portion 372c on the front side in the axial force direction, and a convex portion 372f on the rear side in the axial force direction.

  For the # 3 and # 4 cylinders, an integrated partial rocker shaft 374 is used. Therefore, the partial rocker shaft 374 abuts the end surface 374 a on the front side in the axial force direction against the inner bottom surface of the tip bush 378. Then, the convex portion 374f on the rear side in the axial force direction is disposed in the concave portion 372d in the partial rocker shaft 372 of the # 2 cylinder.

  This prevents relative rotation around the axis between the three partial rocker shafts 370, 372, and 374. Furthermore, since the tip of the rotation prevention pin 394 fixed to the cam carrier side is inserted into the long hole 370e in the # 1 cylinder partial rocker shaft 370, the rocker shaft composed of these partial rocker shafts 370, 372, and 374 is There is no rotation around the axis relative to the cam carrier.

  The axial force of the # 3 cylinder mediation drive mechanism 324 is transmitted to the # 4 cylinder mediation drive mechanism 324 by a cylindrical bush 375 placed on the partial rocker shaft 374. Therefore, the axial force of the intermediary drive mechanism 324 of both the # 3 cylinder and the # 4 cylinder is loaded on the flange portion 378c of the tip bush 378.

According to the third embodiment described above, the following effects can be obtained.
(I). In this way, a plurality of partial rocker shafts 370 to 374 formed separately for each cylinder group composed of one or more cylinders are arranged in the axial direction, and adjacent partial rocker shafts 370 to 374 are brought into contact with each other in the axial direction. Even if a single rocker shaft is used, the same effect as in the first embodiment is produced.

[Other embodiments]
(A). As shown in FIG. 23, the engagement between the partial rocker shafts 470, 472, 474, and 476 may be performed by fitting an engagement pin 473 into a fitting hole formed in the end face. The other configurations such as the mediation drive mechanism 424, the tip bush 478, the control shaft 480, the rotation prevention pin 494, and the like are the same as those in the first embodiment. This engagement may be applied to the third embodiment.

(B). In the third embodiment, the engagement between the partial rocker shafts may be configured as in the second embodiment.
(C). In each of the embodiments described above, the axial force receiving portion is not formed on the partial rocker shafts 76, 276, and 374 corresponding to the tip partial rocker shaft. Instead of this configuration, an axial force receiving portion may be formed also in the tip portion rocker shaft. With this configuration, the axial force of the mediating drive mechanism is not transmitted to the tip bush and positioned, but the axial force is transmitted to the axial force receiving portion for positioning.

  (D). The partial rocker shafts 70, 270, 370, 470 that are prevented from rotating about the axis by the rotation prevention pins 94, 294, 394, 494 with respect to the cam carrier are opposite to the actuator in the arrangement of the partial rocker shafts. It was a partial rocker shaft at the end of. Instead, by defining the length so that the anti-rotation pin does not protrude into the center sliding hole of the partial rocker shaft, the anti-rotation pin can be engaged with the other partial rocker shaft in the array to rotate around the axis. Rotation may be prevented.

1 is a longitudinal sectional view of an engine according to Embodiment 1. FIG. The top view of the engine. FIG. 3 is an explanatory diagram of an arrangement state of the mediation drive mechanism according to the first embodiment. The perspective view which shows the arrangement | positioning state of the intermediary drive mechanism. The perspective view which shows the arrangement | positioning state of the intermediary drive mechanism. The perspective view which decomposes | disassembles and shows the structure of FIGS. 3-5 for every main structure. FIG. 3 is a perspective view of an intermediate drive mechanism for # 1, # 2 cylinders according to the first embodiment. FIG. 3 is a perspective view of an intermediate drive mechanism for # 1, # 2 cylinders according to the first embodiment. Explanatory drawing of the state which combined the rocker shaft of Embodiment 1, the control shaft, the bush for front ends, and the rotation prevention pin. The perspective view which decomposes | disassembles and shows the structure of FIG. FIG. 3 is a main part explanatory view showing an engaged state between the partial rocker shafts of the first embodiment. FIG. 3 is a partially broken perspective view of the mediation drive mechanism according to the first embodiment. The fragmentary perspective view of the mediating drive mechanism. Explanatory drawing of the valve lift pattern by the variable valve mechanism of Embodiment 1. FIG. The front view which shows the arrangement | positioning state of the mediation drive mechanism of Embodiment 2. FIG. The perspective view which shows the arrangement | positioning state of the intermediary drive mechanism. Sectional explanatory drawing of the rocker shaft in Embodiment 2, a control shaft, the bush for front ends, and a shim. The perspective view which decomposes | disassembles and shows the structure of FIG. 15, 16 for every main structure. The perspective view of the partial rocker shaft of Embodiment 2, and the bush for front ends. The perspective view of the partial rocker shaft and the bush for front ends. The principal part explanatory drawing which shows the engagement state between the partial rocker shafts of Embodiment 2. FIG. The perspective view which decomposes | disassembles and shows the structure of Embodiment 3 for every main structure. Explanatory drawing which shows the principal part which shows the other example of the engagement state between partial rocker shafts.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Engine, 2a-2d ... Cylinder, 4 ... Variable valve mechanism, 6 ... Cam carrier, 8 ... Cylinder block, 10 ... Piston, 12 ... Cylinder head, 14 ... Combustion chamber, 16 ... Intake valve, 16a ... Valve spring , 18 ... exhaust valve, 20 ... intake port, 22 ... exhaust port, 24 ... mediation drive mechanism, 26 ... roller rocker arm, 28 ... intake camshaft, 30 ... intake cam, 32 ... actuator, 34 ... variable valve timing mechanism, 36 ... Timing chain, 38 ... Crankshaft, 40 ... Exhaust camshaft, 42 ... Exhaust cam, 44 ... Roller rocker arm, 46 ... Valve timing variable mechanism, 48, 56-62 ... Bearing, 48a, 56a-62a ... Cap, 68 ... Rocker shaft, 70, 72, 74, 76 ... Partial rocker shaft, 70a 76a ... long hole, 70b to 76b ... center sliding hole, 70c, 72c, 74c ... axial force receiving portion, 70d, 72d, 74d ... concave portion, 70e ... long hole, 72e, 74e ... contact surface, 72f, 74f, 76f ... convex part, 78 ... bush for tip, 78a ... inner bottom surface, 78b ... through hole, 78c ... flange part, 80 ... control shaft, 80a ... locking flange, 82, 84 ... shim, 86-92 ... pin, 94 ... Anti-rotation pin, 100 ... Input part, 100d ... Roller, 102,104 ... Oscillating cam, 102d, 104d ... Cam part, 106 ... Slider gear, 106a, 106b, 106c ... Helical spline part, 224 ... Intermediate drive mechanism, 234 , 236, 238, 240 ... tubular bushes, 236a, 238a, 240a ... engaging projections, 248-262 ... cam carrier bearings, 24 a to 262a ... cap, 268 ... rocker shaft, 270, 272, 274, 276 ... partial rocker shaft, 270a, 272a, 274a ... abutment surface, 270c, 272c, 274c ... axial force receiving portion, 270d, 272d, 274d ... Notch, 270e ... long hole, 278 ... tip bush, 280 ... control shaft, 282, 284 ... shim, 282a ... internal space, 294 ... rotation prevention pin, 324 ... mediation drive mechanism, 370, 372, 374 ... partial rocker Shaft, 370c ... axial force receiving portion, 370d ... concave portion, 370e ... long hole, 372c ... axial force receiving portion, 372d ... concave portion, 372f ... convex portion, 374a ... end face, 374f ... convex portion, 375 ... cylindrical bush, 378 ... Bush for tip, 378c ... Flange part, 394 ... Rotation prevention pin, 424 ... Intermediate drive Mechanism, 470, 472, 474, 476 ... partial rocker shaft, 473 ... engagement pin, 478 ... tip bush, 480 ... control shaft, 494 ... rotation prevention pin.

Claims (8)

Each cylinder is provided with an intermediate drive mechanism that mediates the lift drive force of the valve cam of the internal combustion engine to the valve side by being supported by the rocker shaft and swinging around the axis of the rocker shaft, and in the shaft of the rocker shaft A variable valve mechanism that adjusts the valve operating angle in each cylinder of the internal combustion engine by interlocking the valve operating angle adjusting member of the mediation drive mechanism by axial movement of the arranged control shaft;
The rocker shaft is formed by arranging a plurality of partial rocker shafts formed separately for each cylinder group composed of one or more cylinders of an internal combustion engine in the axial direction and bringing adjacent partial rocker shafts into contact with each other. It is considered as a rocker shaft of
The one partial rocker shaft in the arrangement of the partial rocker shafts is prevented from rotating around the axis with respect to the internal combustion engine main body side, and is engaged between adjacent partial rocker shafts. An internal combustion engine variable valve mechanism characterized in that relative rotation about an axis between rocker shafts is prevented. 3. The partial rocker shaft according to claim 1, wherein the partial rocker shaft that is prevented from rotating about the axis with respect to the internal combustion engine main body is a partial rocker shaft that is disposed at one end of the arrangement of the partial rocker shafts. An internal combustion engine variable valve mechanism. 3. An internal combustion engine variable valve mechanism according to claim 2, wherein an actuator for driving the control shaft in the axial direction is disposed on the other end side of the arrangement of the partial rocker shafts. The internal combustion engine according to any one of claims 1 to 3, wherein the partial rocker shafts are engaged with each other around an axis by forming a step in the end surfaces of the adjacent partial rocker shafts. Variable valve mechanism. 5. The axial direction of the entire rocker shaft according to claim 1, wherein the axial position of the tip portion rocker shaft at the distal end in the axial force direction generated in the intermediate drive mechanism by the reaction force from the valve side is used as a reference position. An internal combustion engine variable valve mechanism characterized in that an axial force receiving portion that is positioned and receives an axial force generated in the intermediate drive mechanism is formed at least in each partial rocker shaft other than the tip partial rocker shaft. . 6. The cylinder according to claim 5, wherein a cylindrical body is disposed in a contact portion between the partial rocker shafts in a state of being fixed to the partial rocker shaft on the front side in the axial force direction, and a part of the cylindrical body and the axial force direction An internal combustion engine variable valve operating mechanism characterized in that relative rotation about an axis between partial rocker shafts is prevented by engaging a part of a rear partial rocker shaft about the axis. The internal combustion engine variable valve mechanism according to claim 6, wherein a part of the partial rocker shaft on the rear side in the axial force direction that engages with a part of the cylindrical body is the axial force receiving portion. 8. The shim shaft according to claim 7, wherein a part of the cylindrical body is engaged with a shim disposed between the intermediate drive mechanism and the axial force receiving portion together with the axial force receiving portion. An internal combustion engine variable valve mechanism characterized by suppressing rotation around.

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