JP2018076840A - Variable valve gear of multi-cylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem that a valve closing lift characteristic of an intake valve on a second cylinder side is changed by a sliding resistance between a drive cam of a first cylinder and an oscillation cam of a second cylinder adjacent to the driving cam.SOLUTION: On the premise that a #1 cylinder and a #2 cylinder, in which the opening and closing operations of intake valves are sequentially performed, are arranged adjacently in the engine longitudinal direction and the opening timing of each intake valve of the first cylinder and the closing timing of each intake valve of the #2 cylinder may overlap with each other, by oscillating each oscillation cam 7 via a transmission mechanism 8 with rotation of drive cams 11 rotationally driven by a drive shaft 5, each intake valve is operated to open and close by a swing arm 6. A flat washer 33 working as a sliding resistance reducing member is interposed between the end face 11c of a cylindrical portion 11a of the drive cam 11 of the # 1 cylinder and the opposed end face 7e of a cam shaft 7a of the oscillation cams 7, 7 of the # 2 cylinder.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a variable valve operating apparatus for a multi-cylinder internal combustion engine that variably controls an operation characteristic of an engine valve.

  As a conventional variable valve operating apparatus for a multi-cylinder internal combustion engine, one described in Patent Document 1 below is known.

  This variable valve device is provided with a rotational drive force transmitted from the crankshaft of the engine, a drive shaft provided with a drive cam on the outer periphery, and a swingable arrangement on the outer periphery of the drive shaft. A pair of oscillating cams that open the intake valve against the spring force of the valve spring, a transmission mechanism that converts the rotational motion of the drive cam into oscillating motion and transmits it to each oscillating cam, and this transmission A control mechanism that variably controls the lift amount and operating angle of the engine valve by changing the posture of the mechanism.

  The one drive cam, the pair of swing cams, and the transmission mechanism are provided for each cylinder on the drive shaft.

JP 2010-163980 A

  In the conventional variable valve operating apparatus, as described above, the drive cam and the swing cam are provided for each cylinder. For example, the first cylinder (# 1 cylinder) which is one first cylinder is provided. And a pair of swing cams of the second cylinder (# 2 cylinder) which is the second cylinder adjacent to the first cylinder are arranged adjacent to each other on the drive shaft in the axial direction.

  Therefore, when this variable valve gear is mounted on, for example, an in-line four-cylinder internal combustion engine, the drive cam on the # 1 cylinder side tries to rotate in order to open each intake valve of the # 1 cylinder. The drive shaft is slightly bent and deformed in the lift direction with the rotational load of the drive cam.

  For this reason, the end face in the axial direction of the drive cam and the opposed end face of the swing cam of the # 2 cylinder arranged close to the end face of the drive cam partially slidably contact each other, causing the swing cam to rotate. Therefore, there is a possibility that a slight delay may occur in the closing timing of each intake valve of the # 2 cylinder that has been displaced in the lift direction and is about to close. As a result, for example, the combustion pressure in the # 2 cylinder may decrease, leading to a decrease in engine output.

  The present invention has been devised in view of the above-described technical problem, and reduces the sliding resistance between the drive cam of the first cylinder and the swing cam of the second cylinder adjacent to the drive cam. An object of the present invention is to provide a variable valve system for a multi-cylinder internal combustion engine.

In a preferred aspect of the present invention, the first cylinder and the second cylinder, in which the opening and closing operation of the engine valve is sequentially performed, are arranged adjacent to each other in the longitudinal direction of the engine, and the engine valve of the first cylinder is opened during the engine operation. As a precondition for a variable valve system for a multi-cylinder internal combustion engine in which the timing and the closing timing of the engine valve of the second cylinder may overlap,
The first drive cam and the second swing cam are disposed between the first drive cam on the first cylinder side and the second swing cam on the second cylinder side while being supported on the outer periphery of the drive shaft. And a sliding resistance reducing member that reduces sliding resistance with the moving cam.

  According to a preferred aspect of the present invention, it is possible to reduce the sliding resistance between the drive cam of the first cylinder and the swing cam of the second cylinder adjacent to the drive cam, thereby suppressing the accompanying rotation.

1 is a perspective view showing a first embodiment in which a variable valve device according to the present invention is applied to an in-line four-cylinder internal combustion engine. It is principal part sectional drawing of the variable valve apparatus of this embodiment. It is a principal part side view of the variable valve apparatus of this embodiment. It is a perspective view of the flat washer provided for this embodiment. FIG. 4 is a sectional view taken along line AA in FIG. 3. It is the schematic which shows the displacement of each rocking cam of # 2 cylinder accompanying the bending deformation of a drive shaft at the time of opening operation of the intake valve of # 1 cylinder of this embodiment. FIG. 6 is a characteristic diagram showing the relationship between the drive shaft and the valve lift of each cylinder in the present embodiment, and particularly showing the change in the valve lift of the # 2 cylinder during the valve lift of the # 1 cylinder. It is the schematic which shows the displacement of each rocking cam of # 2 cylinder accompanying the bending deformation of a drive shaft at the time of opening operation of # 1 cylinder in the conventional variable valve apparatus. FIG. 7 is a characteristic diagram showing a relationship between a drive shaft and a valve lift of each cylinder in a conventional variable valve gear, and particularly showing a change in a valve lift of a # 2 cylinder during a valve lift of a # 1 cylinder.

  Embodiments of a variable valve operating apparatus for a multi-cylinder internal combustion engine according to the present invention will be described below with reference to the drawings. In this embodiment, the internal combustion engine is applied to an in-line four-cylinder four-cycle gasoline engine, and the variable valve operating apparatus is applied to the intake valve side.

[First Embodiment]
1 is an overall perspective view of a variable valve operating apparatus for a multi-cylinder internal combustion engine according to a first embodiment, FIG. 2 is a cross-sectional view of the variable valve operating apparatus, and FIG. 3 is an enlarged view of a main part of the variable valve operating apparatus. ing.

  That is, two first and second intake valves 3 and 3 per cylinder, which are engine valves for opening and closing a pair of intake ports 2 and 2 formed in the cylinder head 1, and the first cylinder (# 1 cylinder) to A drive shaft 5 disposed along the longitudinal direction of the engine on the upper side of the fourth cylinder (# 4 cylinder), and rotatably supported on the outer peripheral surface of the drive shaft 5, each of which is connected via a pair of swing arms 6. A rotational force of a pair of swing cams 7, 7 for opening and closing the intake valve 3 and a drive cam 11 integrally provided on the outer peripheral surface of the drive shaft 5 is converted into a swing force and transmitted to each swing cam 7. A transmission mechanism 8 that controls the operating angle and lift amount of each intake valve 3, 3 via the transmission mechanism 8, and a cylinder head 1 that holds each intake air via each swing arm 6. Two valve clearances between the valves 3 and 3 and the swing cams 7 are set to zero lash. First, second hydraulic rush adjuster 10a, includes a 10b, and a point member (pivot).

  The one drive cam 11, the pair of swing cams 7 and 7, and the one transmission mechanism 8 are provided for each of the four cylinders.

  In the in-line four cylinders in this embodiment, the combustion cycle (ignition order) of the first cylinder # 1 to # 4 is the order of # 1 cylinder- # 3 cylinder- # 4 cylinder- # 2 cylinder. For example, when the # 1 cylinder is in the intake process, the # 2 cylinder, which is the second cylinder, is the compression process, the # 3 cylinder is the exhaust process, and the # 4 cylinder is the expansion (explosion) process. . Further, the opening timing of the intake valves 3 and 3 of the # 1 cylinder and the closing timing of the intake valves 3 and 3 of the # 2 cylinder partially overlap, so-called overlapping lift characteristics. That is, for example, when the # 1 cylinder opens the intake valves 3 and 3 in the intake process, the intake valves 3 and 3 are closed to shift to the compression stroke on the adjacent # 2 cylinder side. At this time, the lifts of the valve opening lift and the valve closing lift partially overlap each other.

In the following, for convenience, each component in one cylinder, for example, the # 1 cylinder will be described. Each intake valve 3 is slidably held by the cylinder head 1 via a valve guide 4, and each stem end Each spring retainer 3a is provided in the vicinity. Each intake valve 3 is urged in the closing direction by each valve spring 12 elastically contacted between each spring retainer 3 a and the inner upper surface of the cylinder head 1.

  The drive shaft 5 is rotatably supported by a plurality of bearing portions 13 provided at the upper end portion of the cylinder head 1 and is provided at one end portion 5a (an end portion on the front side) in the axial direction. The rotational force of the crankshaft is transmitted by the timing belt via an external timing pulley.

  Each drive cam 11 has a cam body formed in a disc shape, and a cylindrical portion 11a which is a boss portion provided integrally with one side portion of the cam body, and a connecting pin 11b penetrating through the cylindrical portion 11a. It is fixed to the drive shaft 5. Further, the axis X of the cam body is eccentric in the radial direction from the axis Y of the drive shaft 5, and the cam profile on the outer periphery is formed in an ordinary substantially circular shape.

  Each drive cam 11 is arranged on the right side of each transmission mechanism 8 in the drawing as shown in FIG. The swing cams 7 and 7 are arranged on the opposite side of the drive cams 11 with the transmission mechanisms 8 interposed therebetween.

  As shown in FIG. 2, each swing arm 6 has a concave lower surface of one end 6a in contact with a stem end of each intake valve 3, while a lower surface concave 6c of the other end 6b is connected to each hydraulic lash adjuster 10a, 10b. It is in contact. Further, the swing arm 6 has a roller 14 rotatably accommodated in a housing hole formed in the center via a roller shaft 14a.

  As shown in FIGS. 2 and 3, the pair of swing cams 7 are integrally provided at both ends of the cylindrical cam shaft 7a in the rotation axis direction, and the base circle surface, the ramp surface, and the lift are formed on the lower surface. A cam surface 7b comprising a surface is formed. Each swing cam 7 is configured such that the base circle surface, the ramp surface, and the lift surface are in contact with the upper surface of the roller 14 of the swing arm 6 according to the swing position of the swing cam 7.

  In the camshaft 7a, the drive shaft 5 is slidably inserted, and a journal portion 7c formed at a substantially central position in the axial direction of the outer peripheral surface is rotatably supported by a plurality of bearing portions 13 with a small clearance. Has been. Therefore, the drive shaft 5 is supported by the bearing portion 13 via the camshaft 7a. Further, as shown in FIG. 3, the cam shaft 7a has an end surface 7e of one end portion 7d in the rotation axis direction through a predetermined gap with an end surface 11c which is a front end surface of the cylindrical portion 11a of the adjacent drive cam 11. Opposite from the axial direction.

  A flat washer 33, which is a sliding resistance reducing member, is provided in the gap between the both end faces 7e and 11c via a minute clearance.

  As shown in FIG. 4, the flat washer 33 is a general one, and is formed integrally with a metal material such as iron, for example, and has a thickness of about 1.35 mm. The flat washer 33 is formed with a support hole 33a that is slightly larger than the outer diameter of the drive shaft 5 in the center, and the outer diameter is substantially the same as the outer diameter of the cylindrical portion 11a of the drive cam 11. Is formed.

  The flat washer 33 has a minute clearance between both axial end surfaces 7e and 11c of the cylindrical portion 11a of the drive cam 11 and the camshaft 7a of the swing cam 7 adjacent to the drive cam 11 in all cylinders. Has been placed.

  As shown in FIG. 2, each bearing portion 13 extends upward from the upper deck of the cylinder head 1 so that the camshaft 7 a can freely rotate between the bearing groove on the lower end portion and the bearing groove on the upper surface of the cylinder head 1. A plurality of journal portions 21a of the control shaft 21 described later are supported by a bearing groove at the upper end portion and a bracket 13a fixed to the upper end portion.

  As shown in FIGS. 1 and 2, the transmission mechanism 8 includes a rocker arm 15 disposed above the drive shaft 5, a link arm 16 that links the one end 15 a of the rocker arm 15 and the drive cam 11, and the rocker arm 15. The link rod 17 which links the other end portion 15b and one swing cam 7 is provided.

  The rocker arm 15 has a cylindrical base portion at the center thereof rotatably supported by a control cam 22 (described later) through a support hole, and one end portion 15 a is rotatably connected to the link arm 16 by a pin 18. . On the other hand, the other end 15 b is rotatably connected to the upper end of the link rod 17 via a pin 19.

  Each link arm 16 has a cam body of the drive cam 11 rotatably fitted in a fitting hole at the center position of an annular base portion 16a. On the other hand, the protruding end 16b is rotatably connected to one end portion 15a of the rocker arm 15 via the pin 18.

  Each link rod 17 has a lower end portion rotatably connected to the cam nose portion side of one swing cam 7 via a pin 20.

  An adjustment mechanism 23 is provided between the other end 15b of the rocker arm 15 and the upper end of the link rod 17 to finely adjust the lift amount of each intake valve 3 when each component is assembled.

  The control mechanism 9 includes a control shaft 21 rotatably supported by the same bearing portion 13 at an upper position of the drive shaft 5, and is fixed to the outer periphery of the control shaft 21, and is slidably fitted into a support hole of the rocker arm 15. Thus, a control cam 22 serving as a rocking fulcrum of the rocker arm 15 and an actuator 34 that controls forward and reverse rotation of the control shaft 21 are provided.

  As shown in FIG. 1, the control shaft 21 is disposed in parallel with the drive shaft 5 and along the longitudinal direction of the engine, and the maximum forward / reverse rotational position of the control shaft 21 at one end portion in the rotational shaft direction. A fan-shaped stopper portion 35 constituting a part of the stopper mechanism for restricting the movement is integrally provided. An actuator 34 is linked to one end of the control shaft 21.

  On the other hand, the control cam 22 has a cylindrical shape, and the axial center position is deviated from the axial center of the control shaft 21 by a predetermined amount.

  The actuator 34 includes an electric motor 37 fixed to one end of the housing 36, and a ball screw serving as a speed reduction mechanism that is partially provided inside the housing 36 and transmits the rotational driving force of the electric motor 37 to the control shaft 21. And a mechanism 38.

  The electric motor 37 is constituted by a proportional DC motor, and is controlled to rotate forward and backward by a control signal from a control unit (not shown) that detects the engine operating state.

  As shown in FIG. 1, the ball screw mechanism 38 is accommodated in the ball screw shaft 38 a connected to the motor output shaft of the electric motor 37 and the housing 36, and is rotatable around the outer periphery of the ball screw shaft. A nut portion 38b that is provided and movable in the axial direction, and a link mechanism 38c that links the nut portion 38b and the control shaft 21 are configured.

  Since each hydraulic lash adjuster 10a, 10b is a general one as shown in FIG. 1 and FIG. 2, it will be briefly described. A bottomed cylindrical shape fixed in a cylindrical holding hole 1a of the cylinder head 1 Body 24, a plunger 25 having a spherical shape at the tip end having a reservoir chamber inside through a partition wall (not shown) that is accommodated in the body 24 so as to be vertically slidable, And a high pressure chamber (not shown) that communicates with the reservoir chamber through a communication hole that is formed through the partition wall, and the hydraulic oil in the reservoir chamber is provided only in the direction of the high pressure chamber. And a check valve that allows inflow.

  Further, the cylinder head 1 is formed with a discharge hole 1b for discharging the hydraulic oil accumulated in the holding hole 1a to the outside.

  The body 24 is formed with a cylindrical first concave groove 24a on the outer peripheral surface, and is formed on the peripheral wall of the first concave groove 24a inside the cylinder head 1 so that the downstream end thereof is the first concave groove 24a. A first passage hole (not shown) that communicates between the opened oil passage 30 and the inside of the body 24 is formed to penetrate in the radial direction.

  The oil passage 30 communicates with a main oil gallery 30a for supplying lubricating oil formed in the cylinder head 1, and the main oil gallery 30a is fed with lubricating oil from an oil pump (not shown). It has become.

The plunger 25 is formed with a cylindrical second concave groove at a substantially central position in the axial direction of the outer peripheral surface, and a second passage hole communicating the first passage hole and the reservoir chamber is formed on the peripheral wall of the second concave groove. Penetrated along the direction,
The second groove is formed to have a relatively large axial width so that the first passage hole and the second passage hole are always in communication at any vertical sliding position of the plunger 25 with respect to the body 24. It has become.

  The check valve includes a check ball that opens and closes the lower opening edge (seat) of the communication hole, a coil spring that biases the check ball in the closing direction, and a cup-shaped retainer that holds the coil spring. Yes.

  Then, in the base circle section of each swing cam 7, the plunger 25 moves forward (moves upward) by the biasing force of the coil spring, and the high pressure chamber becomes low pressure. Then, the hydraulic oil supplied from the oil passage 30 flows into the reservoir chamber from the first concave groove through the first passage hole, the second concave groove, and the second passage hole. The hydraulic oil further pushes open the check ball against the spring force of the first coil spring and flows into the high pressure chamber. As a result, the plunger 25 constantly pushes up the other end 6 b of the swing arm 6 and contacts the roller 14 and the swing cam 7 so that the swing cam 7, the one end 6 a of the swing arm 6, and each intake valve 3. The gap between the stem end is adjusted to zero lash.

  The control unit detects engine operating conditions (engine operating conditions) based on information signals from various sensors such as crank sensors, air flow meters, water temperature sensors, and throttle valve angle sensors, and determines the fuel injection amount and ignition timing. It comes to control. The control unit controls the rotation position of the control shaft 21 by controlling forward and reverse rotation of the electric motor 37 based on an information signal from a rotation position sensor (not shown) that detects the engine operating state and the current rotation position of the control shaft 21. Control. Thereby, the valve lift amount and the operating angle of each intake valve 3 and 3 are changed. Here, the operating angle is an open angle from the opening timing of the intake valve 3 to the closing timing.

  Further, a detected portion 31 of a rotation angle sensor that detects the rotation angle of the drive shaft 5 is disposed at one end portion of the drive shaft 5 in the rotation axis direction.

The to-be-detected portion 31 has a cylindrical portion integrally formed at the center of the disc-shaped base portion 31a fixed to the outer peripheral surface of the drive shaft 5 and a plurality of targets 31b around the outer peripheral surface of the base portion 31a. It protrudes at a predetermined position in the direction. The detected portion 31 is formed together when the drive shaft is formed by forging or the like.
[Function and effect of variable valve system]
Hereinafter, the operation of the variable valve operating apparatus in the present embodiment will be described.

  For example, in the low rotation range from the idling operation of the engine, the electric motor 37 is rotationally driven by the control current (pulse signal) output from the control unit, and this rotational torque is transmitted to the control shaft 21 via the ball screw mechanism 38. The When the control shaft 21 is rotationally driven in one direction, the control cam 22 is also rotated in the same direction, the shaft center rotates around the shaft center of the control shaft 21 with the same radius, and the thick portion is removed from the drive shaft 5. It moves away in the upper right direction in FIG. As a result, the other end 15 b of the rocker arm 15 and the pivot point (pin 19) of the link rod 17 move upward with respect to the drive shaft 5, so that each swing cam 7 is interposed via the link rod 17. The cam nose side is forcibly raised.

  Therefore, when the drive cam 11 rotates and pushes up the one end portion 15a of the rocker arm 15 via the link arm 16, the lift amount is transmitted to each swing cam 7 and each swing arm 6 via the link rod 17, The intake valve 3 opens against the spring reaction force of the valve spring 12, and the lift amount becomes sufficiently small.

  For example, when the engine shifts from the low rotation to the middle and high rotation range, the electric motor 37 rotates in reverse by the control current from the control unit and rotates the ball screw mechanism 38 in the same direction. The control shaft 21 rotates the control cam 22 in the other direction, and the axis of the control cam 22 moves downward.

  For this reason, the rocker arm 15 is now moved in the direction of the drive shaft 5 and the cam nose portion of the swing cam 7 is pressed downward via the link rod 17 by the other end portion 15b. The whole is rotated counterclockwise from the position shown in FIG. 2 by a predetermined amount. Therefore, the contact position of the cam surface 7b with respect to the outer peripheral surface of the roller 14 of each swing arm 6 of each swing cam 7 moves to the cam nose portion side (lift portion side).

  For this reason, when the drive cam 11 rotates and pushes up the one end portion 15a of the rocker arm 15 via the link arm 16 when the intake valves 3 and 3 are opened, the intake valves 3 are respectively connected via the swing arms 6. The valve spring 12 opens against the spring force. Each of the intake valves 3 and 3 becomes larger as the rotation increases while continuously changing until the valve lift amount becomes maximum. As a result, the intake charging efficiency is improved and the output can be improved.

  In this embodiment, a flat washer is provided between the end surface 11 c of the cylindrical portion 11 a of the first drive cam 11 and the opposed end surface 7 e of the cam shaft 7 a of the second swing cam 7 that swings by the second drive cam 11. 33 was interposed. For this reason, for example, the # 1 cylinder shifts to the intake process, and the intake valves 3 and 3 of this cylinder are opened (open lift). At the same time, the # 2 cylinder shifts to the compression stroke, and the intake valves 3 of this cylinder. , 3 is closed (lifted closed), even if the drive shaft 5 is bent and deformed by the rotational load of the first drive cam 11 on the # 1 cylinder side, the intake valves 3, 3 of the # 2 cylinder The influence on the closed lift can be sufficiently suppressed.

  That is, as shown in FIG. 8, when the # 1 cylinder drive cam 11 and the # 2 cylinder swing cams 7 and 7 are arranged adjacent to each other in the axial direction as in the prior art, the # 1 cylinder The first drive cam 11 on the # 1 cylinder side tries to rotate against the spring force of the valve spring 12 in order to open the intake valves 3 and 3 on the side. At this time, the drive cam 11 always rotates in the same direction as indicated by the black arrow G in FIG. 8, but this reaction force is indicated by the white arrow F in the figure during the opening operation of the intake valves 3 and 3. Such a large rotational load is generated. In particular, the largest rotational load is generated during the maximum lift of the opening operation of the intake valves 3 and 3, and the load of the first drive cam 11 acts on the drive shaft 5 via the transmission mechanism 8. For this reason, the drive shaft 5 is slightly bent and deformed in the lift direction (in the direction of arrow O in the figure) as indicated by the solid line.

  Along with this, the end surface 11c of the cylindrical portion 11a of the first drive cam 11 and the opposed end surface 7e of the cam shaft 7a of the second swing cams 7 and 7 partially abut as shown in the figure. For this reason, the second rocking cams 7 and 7 of the # 2 cylinder which are going to rock in the valve closing direction (black arrow Q) for the compression stroke are caused by the sliding frictional resistance with the end surface 7e of the first drive cam 11. Along with the first drive cam 11, it is slightly displaced in the valve opening lift direction in the same direction as the rotation.

  Therefore, as shown in FIG. 9, the region where the valve lifts of the intake valves 3 and 3 of the # 1 cylinder and the valve lifts of the intake valves 3 and 3 of the # 2 cylinder overlap (the time area circled in the figure) In the lift region), the height H in the ramp region of the valve lift of the intake valves 3 and 3 of the # 2 cylinder during the closing operation fluctuates more than usual. That is, the lift characteristics of the intake valves 3 and 3 of the # 2 cylinder are affected, and there is a possibility that a delay occurs in the closing timing of the intake valves 3 and 3.

  Thus, when the closing timing of the intake valves 3 and 3 of the # 2 cylinder is delayed, for example, the air-fuel mixture in the cylinder flows back into the intake pipe, leading to a decrease in the effective compression ratio. As a result, the combustion pressure is reduced. It causes a decline. As a result, the engine output is inevitably reduced.

  On the other hand, in this embodiment, as described above, the end surface 11c of the cylindrical portion 11a of the first drive cam 11 of the # 1 cylinder and the camshaft 7a of the second rocking cams 7 and 7 of the # 2 cylinder face each other. By the flat washer 33 interposed between the end surface 7e, the sliding frictional resistance between the cylindrical portion 11a and the camshaft 7a can be reduced. That is, when the intake valves 3 and 3 of the # 1 cylinder are opened and simultaneously the intake valves 3 and 3 of the # 2 cylinder are closed, as shown in FIG. 6, the first drive cam of the # 1 cylinder A large load (open arrow F) is generated at 11 and the drive shaft 5 is slightly bent and deformed in the lift direction (in the direction of arrow O in the figure) as indicated by a solid line. Then, the cylindrical portion 11a is inclined and a part of the end surface 11c comes into contact with one side surface 33b of the flat washer 33, and the other side surface 33c comes into contact with the cam shaft 7a and a part of the opposed end surface 7e. For this reason, since direct contact with the end surface 11c of the cylindrical part 11a and the opposing end surface 7e of the camshaft 7a is avoided, the sliding friction resistance between both 7a and 11c can be reduced effectively.

  Therefore, the rotational force of the first drive cam 11 is not transmitted to the second rocking cams 7 and 7 on the # 2 cylinder side, so that the accompanying rotation of the second rocking cams 7 and 7 is suppressed. Is possible.

  Therefore, as shown in FIG. 7, the opening timing of the intake valves 3 and 3 for the # 1 cylinder overlaps with the closing timing of the intake valves 3 and 3 for the # 2 cylinder (circled area in the figure). The effect on the closing operation (lift) of the intake valves 3 and 3 of the # 2 cylinder is reduced.

  As a result, for example, the proper closing timing of the intake valves 3 and 3 of the # 2 cylinder during the compression stroke is obtained and the backflow of the air-fuel mixture is suppressed, so that the combustion pressure in the cylinder does not decrease. A desired combustion pressure is obtained. As a result, a decrease in the engine output as a whole can be suppressed.

  The influence of the conventional # 2 cylinder on each intake valve 3, 3 is particularly the swing arm 6, as a transmission means for transmitting the swinging force of each swing cam 7, 7 to each intake valve 3, 3. 6 and hydraulic lash adjusters 10a and 10b tend to occur.

  That is, when the hydraulic lash adjusters 10a and 10b are used, the gaps between the intake valves 3 and 3 and the swing arms 6 and 6 are adjusted to zero. Become severe. For this reason, fluctuations in the ramp region are likely to increase, but in this embodiment, a sufficient effect of suppressing these can be obtained.

In this embodiment, the flat washer 33 is interposed between all cylinders as well as between the # 1 cylinder and the # 2 cylinder. In other words, since it is interposed between the adjacent drive cam 11 and the camshaft 7a of the swing cam 7, the drive cam 11 always rotates in the same direction and swings within a predetermined range to partially It is possible to effectively reduce the sliding frictional resistance between the rocking cam 7 (camshaft 7a) that rocks in the direction opposite to the rotation direction. As a result, the swing of the swing cams 7 and 7 in each adjacent cylinder accompanying the rotation of the drive cam 11 in each cylinder is not affected, and a stable opening and closing operation of each intake valve 3 and 3 is ensured at all times. it can.
[Second Embodiment]
Although not shown in the drawings as the second embodiment, it is possible to use an unillustrated collar that is long in the axial direction instead of the flat washer 33 of the first embodiment as a sliding resistance reducing member.

  That is, a collar is interposed between the end surface 11c of the cylindrical portion 11a of the first drive cam 11 in the # 1 cylinder and the opposed end surface 7e of the cam shaft 7a of the second swing cams 7 and 7 in the # 2 cylinder. It is.

  As a result, when the drive shaft 5 is bent and deformed in the opening operation of the intake valves 3 and 3 of the # 1 cylinder, the end surface 11c of the cylindrical portion 11a comes into contact with one end surface in the axial direction of the collar and the opposite end surface 7e of the camshaft 7a. Direct contact with is avoided.

  Therefore, the rotation of the second rocking cams 7 and 7 can be sufficiently suppressed as in the first embodiment. As a result, as described above, the intake operation of the # 2 cylinder in the region where the timing of the opening operation of the intake valves 3 and 3 of the # 1 cylinder and the timing of the closing operation of the intake valves 3 and 3 of the # 2 cylinder overlap. The effect of the closing operation of the valves 3 and 3 on the lift characteristics is reduced.

Further, in the present embodiment, the use of the collar allows the respective axial lengths to be arbitrarily changed, so that the axial length of the entire variable valve operating apparatus can be freely adjusted. Become.
[Third Embodiment]
Furthermore, as a third embodiment, although not shown, for example, a thrust bearing can be used as the sliding resistance reducing member.

  The present invention is not limited to the configuration of the above-described embodiment. For example, when the flat washer 33 and the collar in the first and second embodiments are used, low friction is provided on both side surfaces and both end surfaces in the axial direction. It is also possible to apply the material. As a result, it is possible to more effectively suppress the rotation of the second swing cams 7 and 7.

  Further, the present invention can be applied to any engine having the above-described conditions such as an overlap of opening and closing operations of an engine valve due to a difference in cycle between adjacent cylinders. A 6-cylinder or 8-cylinder engine may be used. When the number of cylinders is four cylinders or more than four cylinders, the combustion interval between the cylinders is narrowed, and thus the effect of the embodiment is increased.

  Further, the present invention can be applied not only to the intake valve but also to the exhaust valve side. In this case, if the closing timing of the exhaust valve in the # 2 cylinder is delayed, for example, not only the air-fuel mixture in the cylinder blows into the exhaust pipe and causes a decrease in the combustion pressure, but also the air flow in the cylinder changes and sufficient intake air is generated. The tumble cannot be obtained, and the combustion is worsened and the combustion pressure is lowered. Therefore, in the present invention, the same effect as that of the intake valve side can be obtained when applied to the exhaust valve side.

  As a valve timing control device for an internal combustion engine based on the embodiment described above, for example, the following modes can be considered.

In one aspect thereof, the first cylinder and the second cylinder in which the opening / closing operation of the engine valve is sequentially performed are disposed adjacent to each other in the longitudinal direction of the engine, and the opening timing of the engine valve of the first cylinder during the engine operation and the A variable valve operating device for a multi-cylinder internal combustion engine in which the closing timing of the engine valve of the second cylinder may overlap,
A drive shaft to which rotational driving force is transmitted from the crankshaft of the engine, a first drive cam and a second drive cam fixed to the outer periphery of the drive shaft for each cylinder, and swingable to the outer periphery of the drive shaft A first rocking cam disposed on one side of the first drive cam opposite to the second drive cam and opening / closing the engine valve of the first cylinder; and on the outer periphery of the drive shaft. A second swing cam that is swingably disposed between the first drive cam and the second drive cam and opens and closes an engine valve of the second cylinder; the first drive cam; A transmission mechanism that converts the rotational motion of the two-drive cam into a swing motion and transmits the swing motion to each of the first swing cam and the second swing cam; and the posture of the transmission mechanism is changed to change the first swing cam. A control mechanism for variably controlling the lift amount of the moving cam and the second rocking cam; And is interposed between the first drive cam and the second swing cam and reduces the sliding resistance between the first drive cam and the second swing cam. And a sliding resistance reducing member.

  As another preferred embodiment, the sliding resistance member is constituted by a metal flat washer.

  As a more preferred aspect, the sliding resistance reducing member is made of a metal collar.

  As a further preferred aspect, the first drive cam has a boss portion extending along the axial direction toward the second drive cam in the rotation axis direction of the drive shaft, and a front end surface of the boss portion and a second The sliding resistance reducing member is disposed between the swing cam and the swing cam.

  According to this aspect, the cylindrical portion 11a (boss portion) of the first drive cam 11 is not adjacent to the portion corresponding to the annular base portion 16a of the first drive cam 11, but the second swing cam 7, 7 to suppress the influence of the first drive cam 11.

  As a further preferred aspect, the second swing cam has a cylindrical cam shaft that is rotatably provided on the outer periphery of the drive shaft, and a pair is provided at both ends of each cam shaft in the rotational axis direction. On the other hand, the sliding resistance reducing member is disposed between the front end surface of the boss portion of the first drive cam and the opposite end surface of the second rocking cam facing the front end surface in the rotational axis direction of the cam shaft. Arranged in a sandwiched state.

  As a more preferable aspect, the multi-cylinder internal combustion engine has four or more inline cylinders.

  DESCRIPTION OF SYMBOLS 1 ... Cylinder head, 1a ... Holding hole, 3 ... Intake valve (engine valve), 5 ... Drive shaft, 6 ... Swing arm, 6a ... One end part, 6b ... Other end part, 7 ... Swing cam, 7a ... Camshaft 7b: Cam surface, 7c: One end, 7e: Opposing end surface, 8: Transmission mechanism, 9: Control mechanism, 10a, 10b: First and second hydraulic lash adjusters, 11: Drive cam, 11a: Cylindrical portion (boss Part), 11c ... end face (tip face), 12 ... valve spring, 13 ... bearing, 14 ... roller, 15 ... rocker arm, 16 ... link arm, 17 ... link rod, # 1 cylinder ... # 1 cylinder, # 2 cylinder ... 2nd cylinder, # 3 cylinder ... 3rd cylinder, # 4 cylinder ... 4th cylinder

Claims (6)

The first cylinder and the second cylinder, in which the opening / closing operation of the engine valve is sequentially performed, are arranged adjacent to each other, and the opening timing of the engine valve of the first cylinder and the closing timing of the engine valve of the second cylinder are determined during engine operation. A variable valve system for a multi-cylinder internal combustion engine that may overlap,
A drive shaft to which the rotational drive force from the crankshaft of the engine is transmitted;
A first drive cam and a second drive cam fixed to the outer periphery of the drive shaft for each cylinder;
A first swing is disposed on the outer periphery of the drive shaft so as to be swingable, and is disposed on one side of the first drive cam opposite to the second drive cam to open and close the engine valve of the first cylinder. A dynamic cam,
A second swing cam disposed on the outer periphery of the drive shaft so as to be swingable, and disposed between the first drive cam and the second drive cam to open and close the engine valve of the second cylinder;
A transmission mechanism that converts the rotational motion of the first drive cam and the second drive cam into a swing motion and transmits the swing motion to each of the first swing cam and the second swing cam;
A control mechanism that variably controls the lift amount of the first rocking cam and the second rocking cam by changing the posture of the transmission mechanism;
In a state where it is supported on the outer periphery of the drive shaft, it is sandwiched between the first drive cam and the second swing cam, and between the first drive cam and the second swing cam. A sliding resistance reducing member for reducing sliding resistance;
A variable valve operating apparatus for a multi-cylinder internal combustion engine. The variable valve operating apparatus for a multi-cylinder internal combustion engine according to claim 1,
The variable valve operating apparatus for a multi-cylinder internal combustion engine, wherein the sliding resistance reducing member is constituted by a flat metal washer. The variable valve operating apparatus for a multi-cylinder internal combustion engine according to claim 1,
The variable valve operating apparatus for a multi-cylinder internal combustion engine, wherein the sliding resistance reducing member is made of a metal collar. The variable valve operating apparatus for a multi-cylinder internal combustion engine according to claim 1,
The first drive cam has a boss portion extending along the axial direction toward the second drive cam in the rotation axis direction of the drive shaft, and between the tip surface of the boss portion and the second swing cam. A variable valve operating apparatus for a multi-cylinder internal combustion engine, wherein the sliding resistance reducing member is disposed in a sandwiched state. The variable valve operating apparatus for a multi-cylinder internal combustion engine according to claim 4,
The second rocking cam has a cylindrical camshaft rotatably provided on the outer periphery of the drive shaft, and a pair of camshafts are provided at both ends of each camshaft in the rotation axis direction.
The sliding resistance reducing member is sandwiched between the front end surface of the boss portion of the first drive cam and the opposite end surface of the second rocking cam facing the front end surface in the rotational axis direction of the cam shaft. A variable valve operating apparatus for a multi-cylinder internal combustion engine, wherein The variable valve operating apparatus for a multi-cylinder internal combustion engine according to claim 1,
A variable valve operating apparatus for a multi-cylinder internal combustion engine, wherein the multi-cylinder internal combustion engine has four or more cylinders in series.

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