JP2008101629A - Variable valve gear for multiple cylinder internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable valve gear for an multiple cylinder internal combustion engine not generating variation of valve lift adjustment quantities among cylinders even if thermal expansion coefficient difference exists. <P>SOLUTION: The variable valve gear comprises a rocker shaft 130 arranged over each cylinder with supported by a plurality of supporting parts provided in the multiple cylinder internal combustion engine, a plurality of intervening drive mechanism 120 arranged with corresponding to each cylinder with supported by the shaft 130, and a control shaft 132 driving a plurality of intervening drive mechanisms 120 by moving in an axial direction in relation to the rocker shaft 130 in the rocker shaft 130. An axial position relation of the intervening drive mechanisms 120 is fixed by attaching a plurality of collars 164 and 166 to the rocker shaft 130 under a condition that axial movement thereof in relation to the rocker shaft 130 is disabled. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a variable valve mechanism for a multi-cylinder internal combustion engine in which a shaft spanned between a plurality of variable valve lift mechanisms provided corresponding to each cylinder of the multi-cylinder internal combustion engine is disposed at a support portion of the internal combustion engine. About.

  A variable valve mechanism that adjusts the valve lift amount of an intake valve or an exhaust valve by driving a variable valve lift mechanism provided on a cylinder head of an internal combustion engine by moving the control shaft in the axial direction is known (for example, a patent) Reference 1).

  In such a variable valve mechanism, in order to rotatably support a plurality of variable valve lift mechanisms arranged in each cylinder, a support pipe (also referred to as a “rocker shaft”) having a control shaft disposed therein is provided as a valve. It is inserted through the center axis position of the variable lift mechanism. As a result, when the valve is driven, the variable valve lift mechanism rotates while being supported by the support pipe.

The support pipe is supported by a standing wall portion (also referred to as “support portion”) provided on the cylinder head side between the variable valve lift mechanisms. The positional relationship between the variable valve lift mechanisms is set by defining the axial position by the standing wall. By setting the positional relationship between the variable valve lift mechanisms with high accuracy by such position regulation by the standing wall, the valve lift amount in each cylinder by the control shaft can be adjusted without causing variation among the cylinders. Is possible.
Japanese Patent Laid-Open No. 2001-263015 (pages 7-8, FIGS. 5-20)

  In recent years, a cylinder block, a cylinder head, or a cam carrier is formed of a light alloy such as aluminum in order to reduce the weight of an internal combustion engine. However, shafts such as control shafts used in variable valve mechanisms are difficult to be made of light alloys such as aluminum because high strength is required, and iron-based materials such as cast steel and cast iron are used.

  For this reason, the coefficient of thermal expansion of the two is greatly different, and control is relatively performed with respect to the interval between the support portions provided on the cylinder head and the cam carrier side when the internal combustion engine is cold and after warm-up. The length of the shaft is shortened. Therefore, the relative positional relationship between the control shaft and the variable valve lift mechanism is different between the base side cylinder and the front end side cylinder of the control shaft, and the valve lift adjustment amount varies among the cylinders. For this reason, it is difficult to adjust the combustion state with high accuracy in all the cylinders, and there is a possibility of causing problems such as deterioration of engine operating state such as engine vibration and emission.

  Further, in order to support the variable valve lift mechanism, a rocker shaft is disposed outside the control shaft as described above. This increases the diameter of the shaft combining the control shaft and the rocker shaft. For this reason, the variable valve lift mechanism itself that inserts these shafts into the center part naturally increases in diameter, and there is a risk that the increase in size and weight of the variable valve mechanism reverses the reduction in size and weight of the internal combustion engine.

  It is an object of the present invention to provide a variable valve mechanism for a multi-cylinder internal combustion engine that does not cause variation in valve lift adjustment amount between cylinders due to the above-described difference in thermal expansion coefficient.

In the following, means for achieving the above object and its effects are described.
(1) The invention according to claim 1 is a pipe-shaped shaft supported by a plurality of support portions provided in a multi-cylinder internal combustion engine and arranged across the cylinders, and a pipe-shaped shaft supported by the pipe-shaped shaft. A plurality of variable valve lift mechanisms arranged in correspondence with each other, and a control shaft that drives the plurality of variable valve lift mechanisms by moving in an axial direction relative to the pipe-shaped shaft within the pipe-shaped shaft. In the variable valve mechanism of a multi-cylinder internal combustion engine provided, the valve lift variable mechanism is attached to the pipe-shaped shaft in a state in which movement in the axial direction is restricted, so that the positional relationship in the axial direction between the valve lift variable mechanisms is Is fixed.

  As a result, the positional relationship between the variable valve lift mechanisms is not affected by the change in the spacing between the support portions, and this is caused by the difference between the thermal expansion coefficient of the cylinder head or cam carrier and the thermal expansion coefficient of the variable valve mechanism. Therefore, it is possible to prevent variation in the valve lift adjustment amount between the cylinders to be performed, and to realize highly accurate valve lift adjustment.

  (2) The invention according to claim 2 is the variable valve mechanism of the multi-cylinder internal combustion engine according to claim 1, wherein the variable valve mechanism is arranged between the support portion and the pipe-shaped shaft and supported by the support portion. A collar including a base portion and a valve lift variable mechanism position defining portion that is provided at an end portion in the axial direction of the base portion and directly or indirectly contacts the end portion of the variable valve lift mechanism. The gist is that the axial positional relationship between the variable valve lift mechanisms is fixed by attaching the collar to the pipe-shaped shaft in a state in which movement in the axial direction with respect to the pipe-shaped shaft is disabled. Yes.

  (3) The invention according to claim 3 is a pipe-shaped shaft supported by a plurality of support portions provided in a multi-cylinder internal combustion engine and arranged across each cylinder, and a pipe-shaped shaft supported by the pipe-shaped shaft. A plurality of variable valve lift mechanisms arranged in correspondence with each other, and a control shaft that drives the plurality of variable valve lift mechanisms by moving in an axial direction relative to the pipe-shaped shaft within the pipe-shaped shaft. In a variable valve mechanism for a multi-cylinder internal combustion engine, a base portion disposed between the support portion and the pipe-shaped shaft and supported by the support portion, and an axial end portion of the base portion is provided. A collar that includes a variable valve lift mechanism position defining portion that directly or indirectly contacts the end of the variable valve lift mechanism. When this collar is attached to the pipe-shaped shaft in a state in which the movement in the axial direction with respect to the pipe-shaped shaft is impossible, the shaft of one valve lift variable mechanism and another variable valve lift mechanism adjacent thereto is attached. The gist is that the positional relationship in the direction is fixed without the support portion.

  (4) The invention according to claim 4 is the variable valve mechanism of the multi-cylinder internal combustion engine according to claim 2 or 3, in which one of the plurality of collars arranged on each of the plurality of support portions. The gist is that movement in the axial direction relative to the support portion is disabled, and the other collars are allowed to move in the axial direction relative to the support portion.

  (5) According to a fifth aspect of the present invention, in the variable valve mechanism of the multi-cylinder internal combustion engine according to the fourth aspect, the collar that cannot be moved in the axial direction is the collar among the plurality of collars. The gist is that the pipe-shaped shaft is arranged on the outermost side in the axial direction.

  (6) According to a sixth aspect of the present invention, in the variable valve mechanism of the multi-cylinder internal combustion engine according to the fifth aspect, the collar that cannot be moved in the axial direction is one end of the control shaft. The gist is that the actuator connected to the portion is supported by the support portion closest to the actuator.

  (7) The invention according to claim 7 is the variable valve mechanism of the multi-cylinder internal combustion engine according to any one of claims 4 to 6, wherein the other collar is a thermal expansion of the multi-cylinder internal combustion engine. Accordingly, the gist is that it is allowed to move in the axial direction with respect to the support portion.

  (8) The invention according to claim 8 is the variable valve mechanism of the multi-cylinder internal combustion engine according to any one of claims 2 to 7, wherein all of the plurality of support portions and the pipe-shaped shaft are provided. The collar is provided in between, the collar is fixed to the support portion in the outermost support portion of the plurality of support portions, and the support portions other than the support portion are in the support portion. The gist of the invention is that the collar is allowed to move in the axial direction with respect to the support portion accompanying the thermal expansion of the multi-cylinder internal combustion engine.

  (9) The invention according to claim 9 is the variable valve mechanism of the multi-cylinder internal combustion engine according to any one of claims 2 to 8, wherein the collar includes its own valve lift variable mechanism position defining portion. The gist is to be supported by the support part in a state where a certain gap is formed between the support part and the support part.

  (10) The invention according to claim 10 is the variable valve mechanism of the multi-cylinder internal combustion engine according to any one of claims 2 to 9, wherein the pipe-shaped shaft, the control shaft, and the collar are the same or The gist is to have an approximate coefficient of thermal expansion.

  (11) The invention according to claim 11 is the variable valve mechanism of the multi-cylinder internal combustion engine according to any one of claims 2 to 10, wherein the pipe-shaped shaft, the control shaft, and the collar are the multiple The gist is that it has a coefficient of thermal expansion different from that of the main body of the cylinder internal combustion engine.

  (12) A twelfth aspect of the present invention is the variable valve mechanism for a multi-cylinder internal combustion engine according to any one of the first to eleventh aspects, in which the variable valve lift mechanism is driven by a camshaft cam. Is input, an output unit that outputs driving force to the valve side of each cylinder, and a slider gear that mediates transmission of driving force from the input unit to the output unit. The slider gear is engaged with each of the input unit and the output unit via two types of splines having different torsion angles, and thereby the input unit and the output unit are moved in the axial direction of the control shaft. The gist is that the two are rotated relative to each other.

(Embodiment 1)
FIG. 1 shows the configuration of a variable valve mechanism in a gasoline engine (hereinafter abbreviated as “engine”) 2 as a multi-cylinder internal combustion engine 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 cam carrier 150 in the upper structure of the engine 2.

  The engine 2 is mounted on the vehicle for driving the vehicle. The engine 2 includes a cylinder block 4, a piston 6, and a cylinder head 8 attached on the cylinder block 4. Among these, the cylinder block 4 and the cylinder head 8 are made of an aluminum alloy material.

  The cylinder block 4 is formed with a plurality of cylinders, in this embodiment, four cylinders 2a. Each cylinder 2a is formed with a combustion chamber 10 partitioned by the cylinder block 4, the piston 6 and the cylinder head 8. ing. In each cylinder 2a, four valves, two intake valves 12 and two exhaust valves 16, are arranged. The intake valve 12 opens and closes the intake port 14, and the exhaust valve 16 opens and closes the exhaust port 18.

  The intake port 14 of each cylinder 2a is connected to a surge tank via an intake passage formed in the intake manifold, and supplies air from the surge tank to each cylinder 2a. A fuel injector is disposed in each intake passage so as to inject fuel into the intake port 14 of each cylinder 2a. In addition to the configuration in which fuel is injected on the upstream side of the intake valve 12 as described above, a direct injection gasoline engine that directly injects fuel into each combustion chamber 10 may be used.

  In this embodiment, since the intake air amount is adjusted by changing the valve lift amount of the intake valve 12, no throttle valve is arranged in the intake passage upstream of the surge tank. However, an auxiliary throttle valve may be arranged. When such an auxiliary throttle valve is arranged, for example, control is performed such that the auxiliary throttle valve is fully opened when the engine 2 is started and the auxiliary throttle valve is fully closed when the engine 2 is stopped. If the valve lift amount cannot be adjusted by the mediation drive mechanism 120 described later, the intake air amount may be controlled by controlling the opening of the auxiliary throttle valve.

  The lift drive of the intake valve 12 is possible by transmitting the valve drive force of the intake cam 45a provided on the intake camshaft 45 via the intermediate drive mechanism 120 and the roller rocker arm 52 arranged in the cylinder head 8. It has become. In this valve driving force transmission, the valve lift amount is adjusted by adjusting the transmission state by the mediation driving mechanism 120 by the function of the slide actuator 100. The intake camshaft 45 is interlocked with the rotation of the crankshaft 49 of the engine 2 via a timing sprocket provided in the variable valve timing mechanism 140 disposed at one end and the timing chain 47.

  The exhaust valve 16 of each cylinder 2a is opened and closed by a constant valve lift amount via a roller rocker arm 54 by an exhaust cam 46a provided on an exhaust camshaft 46 that rotates in conjunction with the rotation of the engine 2. Each exhaust port 18 of each cylinder 2a is connected to an exhaust manifold, and exhaust is discharged to the outside through a purification catalytic converter.

  The intake camshaft 45, the exhaust camshaft 46, the slide actuator 100, the intermediate drive mechanism 120, and the variable valve timing mechanism 140 described above are integrally incorporated in the cam carrier 150. FIG. 3 shows a configuration in which the cam carrier 150 and the cam carrier 150 are arranged. In FIG. 3, the cam cap 152 shown in FIG. 2 is shown in a removed state.

  The cam carrier 150 includes a front side wall 154, a rear side wall 156, and two lateral side walls 158 and 160, and is integrally formed into a rectangle corresponding to the outer peripheral shape of the upper surface of the cylinder head 8. In these side walls 154, 156, 158, 160, four bearings 162 are arranged in parallel so as to communicate between the side walls 158, 160, and are integrally formed with the side walls 154-160. The front side wall 154 also serves as a bearing. The cam carrier 150 is integrally formed of an aluminum alloy material as in the cylinder block 4 and the cylinder head 8.

  An intake camshaft 45 and an exhaust camshaft 46 are rotatably supported in parallel on the bearing 162 and the front side wall 154. Further, between the intake camshaft 45 and the side wall 158, four intermediate drive mechanisms 120 provided for each cylinder and two types of collars 164 and 166 arranged on both sides of the intermediate drive mechanism 120 are arranged. Has been. One rocker shaft 130 common to the four mediating drive mechanisms 120 is supported by penetrating the inside of the collars 164 and 166.

  Here, the configuration of the collars 164 and 166 is shown in FIGS. 4 and 5, (A) is a front view, (B) is a right side view, and (C) is a perspective view. FIG. 4 shows an intermediate collar 164, which is composed of a cylindrical base 164a and two ring-shaped edges 164b formed in a hook shape at both ends thereof. A pin hole 164c passes through the base portion 164a up to the internal space 164d. FIG. 5 shows a collar 166 at both ends, which includes a cylindrical base portion 166a and a ring-shaped edge portion 166b formed in a hook shape at one end. A pin hole 166c passes through the base portion 166a up to the internal space 166d.

These collars 164 and 166 are integrally formed of an iron-based material.
Next, the mediation drive mechanism 120 will be described. 6 is a perspective view of the mediation drive mechanism 120, and FIG. 7 is a partially cutaway perspective view. 7A is a partially broken perspective view of the front side, and FIG. 7B is a partially broken perspective view of the back side. 8 is an exploded perspective view, and FIG. 9 is a cutaway perspective view showing the configuration of the outer portion of the intermediate drive mechanism 120 corresponding to FIG.

  The mediation drive mechanism 120 includes an input unit 122 provided in the center of the figure, a first swing cam 124 (corresponding to an output unit) provided on one end side of the input unit 122, and on the opposite side of the first swing cam 124. A second rocking cam 126 (corresponding to the output portion) provided and a slider gear 128 (FIGS. 7 and 8) disposed inside are provided.

  The housing 122a of the input part 122 forms a space in the axial direction inside, and a helical spline 122b (FIG. 9) formed in a spiral shape of a right-hand screw is formed in the axial direction on the inner peripheral surface of this space. Further, two parallel arms 122c and 122d are formed so as to protrude from the outer peripheral surface of the housing 122a. A shaft 122e parallel to the axial direction of the housing 122a is stretched over the tips of the arms 122c and 122d, and a roller 122f is rotatably attached. As shown in FIG. 1, a biasing force is applied to the arms 122c, 122d or the housing 122a by a spring or the like, so that the roller 122f is always in contact with the intake cam 45a side. Such a spring is provided between the input part 122 and the cylinder head 8 or the rocker shaft 130, for example.

  The housing 124a of the first swing cam 124 forms a space in the axial direction inside, and a helical spline 124b (FIG. 9) formed in a spiral shape of a left-hand screw in the axial direction is formed on the inner peripheral surface of the internal space. Forming. One end of the internal space of the housing 124a is covered with a ring-shaped bearing portion 124c having a center hole with a small diameter. Further, a substantially triangular nose 124d protrudes from the outer peripheral surface. One side of the nose 124d forms a cam surface 124e that curves in a concave shape.

  The housing 126a of the second rocking cam 126 forms a space in the axial direction inside, and a helical spline 126b (FIG. 9) formed in a spiral shape of a left-hand screw in the axial direction is formed on the inner peripheral surface of the internal space. Forming. One end of the internal space of the housing 126a is covered with a ring-shaped bearing portion 126c having a center hole with a small diameter. Further, a substantially triangular nose 126d protrudes from the outer peripheral surface. One side of the nose 126d forms a cam surface 126e that curves in a concave shape.

  As shown in FIG. 8, the first rocking cam 124 and the second rocking cam 126 are arranged so that the end faces are coaxially in contact with the input portion 122 from both sides, and the whole is shown in FIG. As shown, it has a substantially cylindrical shape with an internal space.

  Details of the slider gear 128 arranged in the internal space constituted by the input unit 122 and the two swing cams 124 and 126 are shown in FIGS. 10A is a plan view, FIG. 10B is a front view, and FIG. 10C is a right side view. FIG. 11 is a perspective view, and FIG. 12 is a broken perspective view in the case of breaking vertically along the axis.

  The slider gear 128 has a substantially cylindrical shape, and an input helical spline 128a formed in a spiral shape of a right-hand thread is formed at the center of the outer peripheral surface. A first output helical spline 128c is formed on one end side of the input helical spline 128a so as to have a left-handed spiral shape with a small diameter portion 128b interposed therebetween. On the opposite side of the first output helical spline 128c, a second output helical spline 128e formed in a spiral shape of a left-hand thread with a small diameter portion 128d interposed therebetween is formed. The output helical splines 128c and 128e have a smaller outer diameter than the input helical spline 128a.

  A through hole 128f is formed in the slider gear 128 in the central axis direction. A circumferential groove 128g is formed in the circumferential direction on the inner circumferential surface of the through hole 128f at the position of the input helical spline 128a. The circumferential groove 128g is formed with a pin insertion hole 128h penetrating to the outside in one radial direction.

  Inside the through hole 128f of the slider gear 128, a rocker shaft 130, a part of which is shown in the perspective view of FIG. As shown in FIG. 3, the rocker shaft 130 is provided in common with the four mediating drive mechanisms 120. The rocker shaft 130 has a long hole 130a formed in the axial direction at a position corresponding to each intermediate drive mechanism 120.

  Further, a control shaft 132, a part of which is shown in the perspective view of FIG. 13B, penetrates the inner space 130b of the rocker shaft 130 so as to be slidable in the axial direction as shown in FIG. 13C. Has been placed.

  Although the control shaft 132 is formed in a round bar shape, a support hole 132b in a direction perpendicular to the axis is provided at a position corresponding to each intermediate drive mechanism 120 as shown in FIG. By inserting the base end portion of the control pin 132a into each of the support holes 132b, the control pin 132a is supported so as to protrude in the direction perpendicular to the axis.

  In the state where the control shaft 132 is disposed inside the rocker shaft 130, the tip of each control pin 132a penetrates the long hole 130a formed in the rocker shaft 130, and as shown in the partially broken view of FIG. It is inserted into a peripheral groove 128g formed on the inner peripheral surface of the gear 128.

Since the rocker shaft 130, the control shaft 132, and the control pin 132a require high strength, they are made of an iron-based material.
One end side of the control shaft 132 forms a ball screw shaft driven by the slide actuator 100. As a result, a driving force in the axial direction is received from the slide actuator 100.

  The control shaft 132 is inserted into the rocker shaft 130 described above, and the intermediate drive mechanism 120 and the collars 164 and 166 are alternately arranged on the rocker shaft 130 as shown in FIG. Then, the control pin 132a is inserted into the support hole 132b of the control shaft 132 through the pin insertion hole 128h of the slider gear 128 and the long hole 130a of the rocker shaft 130 as shown in FIG. Then, as shown in FIG. 15, the fixing pin 168 is inserted into the pin holes 164 c and 166 c of the collars 164 and 166 and inserted into the pin hole 130 c (FIG. 13) of the rocker shaft 130. As a result, the collars 164 and 166 are fixed to the rocker shaft 130. Only one collar 166 on the slide actuator 100 side is inserted into the pin hole 130c of the rocker shaft 130 through the pin hole 166c of the collar 166 when the cam cap 152 is fixed. It is fixed by doing.

  In this way, the intermediate drive mechanism 120, the rocker shaft 130, the control shaft 132, and the collars 164 and 166 are integrated as shown in FIG. In such an assembly, in order to adjust the position of each mediation drive mechanism 120, a shim 172 made of a ferrous material for gap adjustment is provided between the mediation drive mechanism 120 and the collars 164, 166 as necessary. Placed in. In this way, the collars 164 and 166 are in contact with the end portions of the mediation drive mechanism 120 directly at the ring-shaped edge portions 164b and 166b or indirectly through the shim 172.

  Therefore, the configuration shown in FIG. 16 is all made of an iron-based material, and this configuration is attached to the cam carrier 150 by the cam cap 152 as shown in FIG. Accordingly, the configuration shown in FIG. 16 is prevented from moving in the axial direction on the cam carrier 150 by the bolt 170 for fixing the cam cap. The other cam cap 152 does not prevent the collars 164 and 166 from moving in the axial direction.

  The axial lengths of the base portions 164a and 166a of the collars 164 and 166 are larger than the widths of the front side wall 154, the bearing 162, and the cam cap 152 as shown in FIGS. For this reason, as shown in the partial longitudinal sectional view of FIG. 17, a clearance is formed between the ring-shaped edge portions 164 b and 166 b and the front side wall 154, the bearing 162 and the cam cap 152. Therefore, the cam carrier 150 and the configuration of FIG. 16 slide in the axial direction at the portion of the cam cap 152 other than the bolt 170 for fixing the cam cap, even if there is a difference in expansion and contraction due to the difference in thermal expansion coefficient. Can be absorbed.

  In such a configuration, the ball screw mechanism 210 (FIGS. 2 and 3) is driven by the slide actuator 100 and the ball screw shaft 174 integrally formed with the control shaft 132 is moved in the axial direction. The position of the slider gear 128 in the axial direction can be adjusted.

  As shown in FIG. 14, since the slider gear 128 is locked to the control pin 132a by the circumferential groove 128g, the slider gear 128 can swing about the axis regardless of the position of the control pin 132a.

  In the slider gear 128, the input helical spline 128 a is engaged with the helical spline 122 b inside the input unit 122. Further, the first output helical spline 128 c is meshed with the helical spline 124 b inside the first swing cam 124, and the second output helical spline 128 e is meshed with the helical spline 126 b inside the second swing cam 126. Here, the input-side splines 122b and 128a and the output-side splines 124b, 128c, 126b, and 128e have different twist directions, and thus have different twist angles.

  As shown in FIG. 16, all the intermediate drive mechanisms 120 have collars 164 and 166 fixed to the rocker shaft 130 on both sides, so that the input portion 122 and the swing cams 124 and 126 of the intermediate drive mechanism 120 are arranged. Is fixed to the rocker shaft 130 in the axial direction. Thus, even if the control shaft 132 moves the slider gear 128 in the axial direction, the input unit 122 and the swing cams 124 and 126 do not move in the axial direction.

  Therefore, by adjusting the axial movement amount of the slider gear 128 in the internal space of the mediation drive mechanism 120, the input portion 122 and the swing cam 124 are functioned by the functions of the helical splines 128a, 122b, 128c, 124b, 128e, 126b. , 126 can be rotated relative to each other. As a result, the positional relationship between the roller 122f and the noses 124d and 126d can be changed, and the valve lift amount of the intake valve 12 can be adjusted.

  Here, FIG. 18 shows a state of the mediation drive mechanism 120 when the drive force of the slide actuator 100 is adjusted to move the control shaft 132 in the L direction (arrow in FIG. 16) as much as possible. 18A is when the intake valve 12 is closed, and FIG. 18B is when the valve is open. In this case, the relative positional relationship between the roller 122f of the input unit 122 and the noses 124d and 126d of the swing cams 124 and 126 is the closest. Therefore, as shown in FIG. 18B, even if the intake cam 45a pushes down the roller 122f of the input portion 122 to the maximum extent, the push-down amount of the rocker roller 52a by the cam surfaces 124e and 126e of the noses 124d and 126d is minimized. The valve lift amount of the intake valve 12 is minimized. Therefore, the amount of intake air from the intake port 14 into the combustion chamber 10 is also minimized.

  FIG. 19 shows a state of the mediation drive mechanism 120 when the drive force of the slide actuator 100 is adjusted to move the control shaft 132 in the H direction (arrow in FIG. 16) as much as possible. 19A is when the intake valve 12 is closed, and FIG. 19B is when the valve is open. In this case, the relative positional relationship between the roller 122f of the input unit 122 and the noses 124d and 126d of the swing cams 124 and 126 is the farthest. For this reason, as shown in FIG. 19B, when the intake cam 45a pushes down the roller 122f of the input portion 122 to the maximum extent, the push-down amount of the rocker roller 52a by the cam surfaces 124e and 126e of the noses 124d and 126d becomes maximum. The valve lift amount of the intake valve 12 is maximized. Therefore, the amount of intake air from the intake port 14 into the combustion chamber 10 is also maximized.

  The valve lift amount of the intake valve 12 can be continuously adjusted by continuously adjusting the axial position of the control shaft 132 between the state of FIG. 18 and the state of FIG. That is, in the present embodiment, it is possible to adjust the intake air amount steplessly without using a throttle valve.

  As shown in FIG. 18B, the minimum valve lift amount of the intake valve 12 has a certain degree of opening, but the valve lift amount “0”, that is, the intake valve 12 is completely closed. In this case, the amount of intake air is “0”.

  In the configuration described above, the intermediary drive mechanism 120 is a variable valve lift mechanism, the rocker shaft 130 is a shaft (pipe-like shaft), the front side wall 154 and the bearing 162 of the cam carrier 150 are support portions, The ring-shaped edge portions 164b and 166b correspond to the valve lift variable mechanism position defining portion.

According to the first embodiment described above, the following effects can be obtained.
(I). The ring-shaped edge portions 164b and 166b of the collars 164 and 166 abut directly or indirectly with the end portions of the swing cams 124 and 126, which are the end portions of the intermediate drive mechanism 120, via the shim 172. The positional relationship in the axial direction between 120 is defined. In addition, a clearance is formed between the ring-shaped edge portions 164 b and 166 b and the front side wall 154, the bearing 162 and the cam cap 152.

  Therefore, a change in the distance between the front side wall 154 of the cam carrier 150 and the bearing 162 does not affect the positional relationship between the mediation drive mechanisms 120. For this reason, even if there is a difference in thermal expansion coefficient between the cam carrier 150 and the control shaft 132, the positional relationship between the mediation drive mechanisms 120 is not affected by the thermal expansion of the cam carrier 150. The collars 164 and 166, the input unit 122, and the swing cams 124 and 126 are affected by thermal expansion.

  The collars 164 and 166, the input part 122, and the swing cams 124 and 126 are made of an iron-based material having the same or similar thermal expansion coefficient as that of the control shaft 132. Therefore, even if a temperature change occurs, the positional relationship of the slider gear 128 whose positional relationship is defined by the control shaft 132 and the positional relationship of the input unit 122 and the swing cams 124 and 126 show substantially the same change. The same lift adjustment amount can be set in the intake valve 12 of each cylinder. For this reason, even if a temperature change occurs, variations in the lift adjustment amount among the cylinders can be prevented, and the valve lift amount can be adjusted with high accuracy.

(Embodiment 2)
In the present embodiment, unlike the first embodiment, a variable valve mechanism is configured without using a rocker shaft. Here, as shown in FIG. 20, the collar 364 functions as a rotation shaft of the mediation drive mechanism 320. FIG. 20 corresponds to FIG. 3 of the first embodiment, and shows the cam carrier 350 and the configuration arranged on the cam carrier 350 with the cam cap removed. In the present embodiment, the cylinder block, the cylinder head, and the cam carrier 350 are made of an iron-based material.

  The configuration of the collar 364 is shown in FIG. 21A is a front view, FIG. 21B is a right side view, and FIG. 21C is a perspective view. The collar 364 includes a cylindrical base portion 364a, two ring-shaped edge portions 364b formed in a bowl shape at both ends, and two rotating shaft portions 364c protruding further on both sides, and a central hole 364d in the shaft portion. Has penetrated. The collar 364 is made of an iron-based material.

  As shown in FIG. 22, the collar 364 has a central hole 364d directly penetrated by a control shaft 332. 23. Instead of the rocker shaft, the intermediate drive mechanism 320 is engaged at its ends by the rotating shaft portions 364c of the collar 364 disposed on both sides of the intermediate drive mechanism 320 as shown in FIG. It is engaged at 324 and 326 portions and is rotatably supported. A control shaft 332 that passes through the center hole 364d of the collar 364 is engaged with the slider gear 328 by the control pin 332a as shown in FIG. 24 so that the slider gear 328 can be moved in the axial direction. Since the rocker shaft does not penetrate the entire mediation drive mechanism 320 as described above, the diameter of the mediation drive mechanism 320 is made smaller by the amount of the rocker shaft than in the case of the first embodiment.

  As shown in FIG. 25, a structure in which a shim 372 is interposed as required and the intermediate drive mechanism 320 of all cylinders is supported by the collar 364 is arranged on the cam carrier 350 as shown in FIG. Yes. In each collar 364, the interval between the ring-shaped edge portions 364b is the same as the width of the front side wall 354 and the bearing 362 of the cam carrier 350. When arranged as shown in FIG. The axial position is fixed by fitting rotatably to 362. As a result, the axial position of each intermediary drive mechanism 320 (in particular, the input portion 322 and the swing cams 324 and 326) is also fixed.

In the configuration described above, the relationship with the claims corresponds to the control shaft 332 corresponding to the shaft and the rotation shaft portion 364c corresponding to the variable valve lift mechanism position defining portion.
According to the second embodiment described above, the following effects can be obtained.

  (I). By using the collar 364 provided with the rotation shaft portion 364c, the rotation shaft portion 364c can be engaged with the end portion of the mediation drive mechanism 320, and the entire mediation drive mechanism 320 does not penetrate through the rocker shaft. It can function as a rotation shaft of the mediation drive mechanism 320. For this reason, without increasing the diameter of the mediation drive mechanism 320, it is possible to suppress the increase in size and weight of the entire variable valve mechanism.

(Embodiment 3)
In the present embodiment, as shown in FIG. 26, the basic configuration of each collar 564 is the same as that of the second embodiment. The difference is that in each collar 564, the interval between the ring-shaped edge portions 564b is larger than the width of the front side wall 554 of the cam carrier 550 and the bearing 562, and each collar 564 has a front side wall 554 similar to the case of the first embodiment. The bearing 562 is slidable in the axial direction. FIG. 26 corresponds to FIG. 3 of the first embodiment, and shows the cam carrier 550 and the configuration disposed on the cam carrier 550 with the cam cap removed.

  With this configuration, the mediation drive mechanism 520 can be rotated by the rotation shaft portion 564c of the collar 564 without using the rocker shaft. The collar 564 at the end opposite to the slide actuator 500 is prevented from moving in the axial direction by a pin 565 on the front side wall 554. In order to maintain a direct contact state between the mediation drive mechanism 520 and the collar 564 or indirectly via the shim 572, the collar 564 at the end on the slide actuator 500 side is biased toward the mediation drive mechanism 520 side by a spring 567. Has been.

  In the present embodiment, the cylinder block, the cylinder head, and the cam carrier 550 are made of an aluminum alloy material. The mediation drive mechanism 520, the collar 564, and the shim 572 are made of an iron-based material.

  In the above-described configuration, the control shaft 532 corresponds to the shaft, and the ring-shaped edge portion 564b and the rotation shaft portion 564c correspond to the valve lift variable mechanism position defining portion.

According to the third embodiment described above, the following effects can be obtained.
(I). The ring-shaped edge 564b of the collar 564 abuts directly or indirectly via shims 572 on the ends of the swing cams 524, 526, which are the ends of the mediation drive mechanism 520, so that the shafts of the mediation drive mechanisms 520 are connected to each other. It defines the positional relationship in the direction. A clearance is formed between the ring-shaped edge 564b, the bearing 562, and the cam cap. Therefore, the positional relationship between the mediation drive mechanisms 520 is always affected only by the thermal expansion of the collar 564, the input unit 522, and the swing cams 524, 526.

  The collar 564, the input unit 522, and the swing cams 524 and 526 are made of an iron-based material having the same or similar thermal expansion coefficient as that of the control shaft 532. Therefore, even if the temperature changes, the positional relationship of the slider gear inside the intermediate drive mechanism 520 whose position is regulated by the control shaft 532 and the positional relationship of the input unit 522 and the swing cams 524 and 526 are the same. As shown, the same lift adjustment amount can be set in the intake valve of each cylinder. In this way, even if a temperature change occurs, variation in lift adjustment amount between cylinders can be prevented, and highly accurate valve lift amount adjustment can be performed.

  (B). Even if the rotation shaft portion 564c of the collar 564 is engaged with the end portion of the mediation drive mechanism 520 and the entire mediation drive mechanism 520 is not penetrated by the rocker shaft, it can function as the rotation shaft of the mediation drive mechanism 520. For this reason, the intermediate drive mechanism 520 is not increased in diameter, and the increase in size and weight of the entire variable valve mechanism can be suppressed.

(Other embodiments)
(A). In each of the above embodiments, an example of an engine using a cam carrier has been described. However, the present invention can also be applied to an engine in which an intermediate drive mechanism and a camshaft are arranged directly on a cylinder head.

  The engine can be applied not only to a gasoline engine but also to a diesel engine. Furthermore, the present invention can be applied not only to driving a vehicle but also to an engine for other purposes. Furthermore, the present invention can be applied not only to the adjustment of the valve lift amount of the intake valve but also to the exhaust valve, and may be applied to the adjustment of the valve lift amount of both the intake valve and the exhaust valve.

  (B). In each of the above embodiments, examples of the collars arranged on the bearings in the cam carrier and the cylinder head are shown. In addition to this, when a pipe-like shaft (rocker shaft) that covers the outside of the control shaft is used as in the first embodiment, the mediation drive mechanism is axially driven by a pin provided on the rocker shaft instead of the collar described above. You may be prevented from moving to. As a result, the positional relationship in the axial direction between the mediation drive mechanisms is fixed by the rocker shaft spanned between the mediation drive mechanisms, and the distance between the cam carrier and the bearing on the cylinder head side is determined between the mediation drive mechanisms. It is possible not to affect the positional relationship.

  For this reason, even if the cylinder head and the cam carrier side are formed of a light alloy or the like, the variable valve mechanism can be formed by selecting the material from other viewpoints such as the strength without being affected by the thermal expansion. . For this reason, even if a temperature change occurs, variation in the valve lift adjustment amount can be prevented, and highly accurate valve lift adjustment can be performed.

FIG. 3 is a longitudinal cross-sectional view of the engine and variable valve mechanism of the first embodiment. The top view which shows the upper part structure of the said engine. The top view which shows the structure arrange | positioned on the cam carrier of Embodiment 1, and a cam carrier. FIG. 3 is an explanatory diagram of a color configuration according to Embodiment 1; FIG. 3 is an explanatory diagram of a color configuration according to Embodiment 1; FIG. 3 is a perspective view of a mediation drive mechanism used in the variable valve mechanism of the first embodiment. FIG. 3 is a partially broken perspective view of the mediation drive mechanism according to the first embodiment. FIG. 3 is an exploded perspective view of the mediation drive mechanism according to the first embodiment. FIG. 3 is a cutaway perspective view of an outer portion of the mediation drive mechanism of the first embodiment. FIG. 3 is a configuration explanatory diagram of a slider gear disposed in the mediation drive mechanism of the first embodiment. FIG. 3 is a perspective view of the slider gear according to the first embodiment. FIG. 3 is a vertically broken perspective view of the slider gear according to the first embodiment. The structure explanatory drawing about the rocker shaft and control shaft of Embodiment 1. FIG. FIG. 3 is a partial cutaway view of the mediation drive mechanism of the first embodiment. FIG. 3 is an explanatory diagram illustrating an arrangement state of a mediation drive mechanism and a collar according to the first embodiment. FIG. 3 is an explanatory diagram of an assembly state of a mediation drive mechanism and a collar according to the first embodiment. The fragmentary longitudinal cross-section explaining the clearance state of the collar of Embodiment 1 and the cam carrier side. FIG. 5 is an operation explanatory diagram of the mediation drive mechanism of the first embodiment. FIG. 5 is an operation explanatory diagram of the mediation drive mechanism of the first embodiment. The top view which shows the structure arrange | positioned on the cam carrier of Embodiment 2, and a cam carrier. FIG. 6 is an explanatory diagram of a color configuration according to a second embodiment. FIG. 6 is an explanatory diagram of a color arrangement state according to the second embodiment. FIG. 6 is an explanatory diagram illustrating a support state of the mediation drive mechanism according to the second embodiment. FIG. 10 is a partial cutaway view of the mediation drive mechanism of the second embodiment. FIG. 6 is an explanatory diagram of an assembled state of a mediation drive mechanism and a collar according to a second embodiment. The top view which shows the structure arrange | positioned on the cam carrier of Embodiment 3, and a cam carrier.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Engine, 2a ... Cylinder, 4 ... Cylinder block, 6 ... Piston, 8 ... Cylinder head, 10 ... Combustion chamber, 12 ... Intake valve, 14 ... Intake port, 16 ... Exhaust valve, 18 ... Exhaust port, 45 ... Intake Camshaft, 45a ... intake cam, 46 ... exhaust camshaft, 46a ... exhaust cam, 47 ... timing chain, 49 ... crankshaft, 52 ... roller rocker arm, 52a ... rocker roller, 54 ... roller rocker arm, 100 ... slide actuator 120 ... Intermediate drive mechanism, 122 ... Input section, 122a ... Housing, 122b ... Helical spline, 122c, 122d ... Arm, 122e ... Shaft, 122f ... Roller, 124 ... First swing cam, 124a ... Housing, 124b ... Helical Spline, 124c ... bearing portion, 12 d ... Nose, 124e ... Cam surface, 126 ... Second swing cam, 126a ... Housing, 126b ... Helical spline, 126c ... Bearing, 126d ... Nose, 126e ... Cam surface, 128 ... Slider gear, 128a ... Input helical Spline, 128b ... small diameter portion, 128c ... first output helical spline, 128d ... small diameter portion, 128e ... second output helical spline, 128f ... through hole, 128g ... circular groove, 128h ... pin insertion hole, 130 ... rocker shaft , 130a ... long hole, 130b ... internal space, 130c ... pin hole, 132 ... control shaft, 132a ... control pin, 132b ... support hole, 140 ... variable valve timing mechanism, 150 ... cam carrier, 152 ... cam cap, 154 ... Front side wall, 156 ... Back side wall, 158 160 ... lateral side wall, 162 ... bearing, 164,166 ... collar, 164a, 166a ... base, 164b, 166b ... ring edge, 164c, 166c ... pin hole, 164d, 166d ... internal space, 168 ... fixing pin, 170 ... Bolt, 172 ... Shim, 174 ... Ball screw shaft, 210 ... Ball screw mechanism, 320 ... Intermediate drive mechanism, 322 ... Input unit, 324,326 ... Oscillating cam, 328 ... Slider gear, 332 ... Control shaft, 332a ... Control pin 350, cam carrier, 354, front side wall, 362, bearing, 364, collar, 364a, base, 364b, ring-shaped edge, 364c, rotating shaft, 364d, center hole, 372, shim, 500, slide actuator 520 ... Intermediate drive mechanism, 522 ... Input unit, 524,526 ... Swing Moving cam, 532 ... control shaft, 550 ... cam carrier, 554 ... front side wall, 562 ... bearing, 564 ... collar, 564b ... ring-shaped edge, 564c ... rotating shaft, 565 ... pin, 567 ... spring, 572 ... Sim.

Claims (12)

A pipe-shaped shaft supported by a plurality of support portions provided in a multi-cylinder internal combustion engine and disposed across each cylinder, and a plurality of valve lifts supported by the pipe-shaped shaft and disposed corresponding to each cylinder In a variable valve mechanism of a multi-cylinder internal combustion engine comprising: a variable mechanism; and a control shaft that drives the plurality of variable valve lift mechanisms by moving in the axial direction with respect to the pipe shaft in the pipe shaft.
A multi-cylinder internal combustion engine characterized in that an axial positional relationship between the variable valve lift mechanisms is fixed by attaching the variable valve lift mechanism to the pipe-shaped shaft in a state where movement in the axial direction is restricted. Variable valve mechanism of the engine. The variable valve mechanism for a multi-cylinder internal combustion engine according to claim 1,
A base portion disposed between the support portion and the pipe-shaped shaft and supported by the support portion, and provided at an end portion in the axial direction of the base portion, directly or indirectly at the end portion of the variable valve lift mechanism A collar configured to include a valve lift variable mechanism position defining portion that comes into contact with the pipe in a state where the collar cannot be moved in the axial direction with respect to the pipe-shaped shaft. A variable valve mechanism for a multi-cylinder internal combustion engine, wherein the axial positional relationship between the variable valve lift mechanisms is fixed. A pipe-shaped shaft supported by a plurality of support portions provided in a multi-cylinder internal combustion engine and disposed across each cylinder, and a plurality of valve lifts supported by the pipe-shaped shaft and disposed corresponding to each cylinder In a variable valve mechanism of a multi-cylinder internal combustion engine comprising: a variable mechanism; and a control shaft that drives the plurality of variable valve lift mechanisms by moving in the axial direction with respect to the pipe shaft in the pipe shaft.
A base portion disposed between the support portion and the pipe-shaped shaft and supported by the support portion, and provided at an end portion in the axial direction of the base portion, directly or indirectly at the end portion of the variable valve lift mechanism A collar configured to include a valve lift variable mechanism position defining portion that comes into contact with the pipe in a state where the collar cannot be moved in the axial direction with respect to the pipe-shaped shaft. A variable valve mechanism for a multi-cylinder internal combustion engine, wherein the positional relationship in the axial direction between one variable valve lift mechanism and another variable valve lift mechanism adjacent thereto is fixed without the support portion. The variable valve mechanism for a multi-cylinder internal combustion engine according to claim 2 or 3,
Of the plurality of collars arranged on each of the plurality of support portions, one of the collars is not allowed to move in the axial direction with respect to the support portion, and the other collars are allowed to move in the axial direction with respect to the support portion. A variable valve mechanism for a multi-cylinder internal combustion engine. The variable valve mechanism for a multi-cylinder internal combustion engine according to claim 4,
The collar that cannot be moved in the axial direction is arranged on the outermost side in the axial direction of the pipe-shaped shaft among the plurality of collars. mechanism. The variable valve mechanism for a multi-cylinder internal combustion engine according to claim 5,
The collar that cannot be moved in the axial direction is supported by a support portion closest to the actuator connected to one end of the control shaft. A variable valve mechanism for a multi-cylinder internal combustion engine. The variable valve mechanism for a multi-cylinder internal combustion engine according to any one of claims 4 to 6,
The variable collar mechanism for a multi-cylinder internal combustion engine, wherein the other collar is allowed to move in the axial direction with respect to the support portion in accordance with thermal expansion of the multi-cylinder internal combustion engine. The variable valve mechanism for a multi-cylinder internal combustion engine according to any one of claims 2 to 7,
The collar is provided between all of the plurality of support portions and the pipe-shaped shaft, and the collar is fixed to the support portion in the outermost support portion of the plurality of support portions, In the other support parts excluding one support part, the collar is allowed to move in the axial direction with respect to the support part accompanying thermal expansion of the multi-cylinder internal combustion engine. Variable valve mechanism. The variable valve mechanism for a multi-cylinder internal combustion engine according to any one of claims 2 to 8,
The collar is supported by the support portion in a state where a constant gap is formed between the valve lift variable mechanism position defining portion and the support portion. mechanism. The variable valve mechanism for a multi-cylinder internal combustion engine according to any one of claims 2 to 9,
The variable valve mechanism for a multi-cylinder internal combustion engine, wherein the pipe-shaped shaft, the control shaft, and the collar have the same or similar thermal expansion coefficient. In the variable valve mechanism of the multi-cylinder internal combustion engine according to any one of claims 2 to 10,
The variable valve mechanism for a multi-cylinder internal combustion engine, wherein the pipe-shaped shaft, the control shaft, and the collar have a different coefficient of thermal expansion from that of the main body of the multi-cylinder internal combustion engine. The variable valve mechanism for a multi-cylinder internal combustion engine according to any one of claims 1 to 11,
The variable valve lift mechanism includes an input unit that receives driving force from a cam of a camshaft, an output unit that outputs driving force to the valve side of each cylinder, and transmission of driving force from the input unit to the output unit. Including a slider gear that mediates
The slider gear engages with each of the input unit and the output unit via two types of splines having different torsion angles, thereby causing the input unit and the output unit to move relative to each other as the control shaft moves in the axial direction. A variable valve mechanism for a multi-cylinder internal combustion engine characterized by being rotated.

Images