JP4085886B2 - Variable valve operating device for internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a variable valve operating apparatus for an internal combustion engine capable of changing the drive phases and valve lift amounts of intake and exhaust valves.
[0002]
[Prior art]
It is known to change the valve phase or lift amount of an intake / exhaust system in accordance with the operating state of an internal combustion engine in order to prevent exhaust gas from an internal combustion engine such as an automobile engine or reduce fuel consumption. As a variable valve apparatus for that purpose, a vane type variable phase valve apparatus is known in which the cam phase is continuously changed by oil pressure.
[0003]
There is also known a cam-switching type valve gear that adapts the drive phase and lift amount of the valve to the operating state by switching a plurality of types of cams according to the operating state of the internal combustion engine.
Alternatively, there is also known a mechanical continuous variable valve device that uses a gear driven by a stepping motor, an intermediate lever, a return spring, and the like so that the drive phase and lift amount of the valve can be changed (for example, Patent Document 1).
[0004]
[Patent Document 1]
Japanese Patent No. 3245492
[0005]
[Problems to be solved by the invention]
However, the vane type variable phase valve device can change the valve drive phase by changing the position of the vane, but cannot change the lift amount of the valve.
[0006]
On the other hand, the cam-switching valve system and the mechanical continuously variable valve system can shift the lift amount and phase, but the cam-switching valve system requires multiple types of cams. The number is complicated and the structure is complicated. In addition, the mechanical continuous variable valve device requires a mechanism for changing the lift amount and a mechanism for changing the phase separately, which complicates the structure and increases the size.
[0007]
Further, in the case of the conventional general continuous phase variable valve operating device, if the closing timing of the intake valve is retarded, the valve opening start timing is also retarded. For this reason, there is a problem that intake and exhaust valve overlaps are reduced or eliminated, and fuel consumption deteriorates due to pumping loss.
[0008]
The present invention has been devised in view of such problems, so that the valve drive phase and the valve lift amount can be continuously changed with a simple configuration without reducing the valve overlap. An object of the present invention is to provide a variable valve operating apparatus for an internal combustion engine.
[0009]
[Means for Solving the Problems]
For this reason, the variable valve operating apparatus for an internal combustion engine according to the present invention is driven by a camshaft provided rotatably in the internal combustion engine, a rocker shaft provided in the internal combustion engine, and a cam formed on the camshaft. A rocker arm mechanism for opening and closing the intake valve or the exhaust valve, and the rocker arm mechanism is swingably supported by the rocker shaft and can drive the intake valve or the exhaust valve, and the cam. A second arm that is driven and swings about the rocker shaft side as a fulcrum, and is swingably provided on a support shaft disposed in the vicinity of the rocker shaft, and is displaced by the swing of the second arm. And a variable mechanism for displacing the fulcrum of the second arm on the rocker shaft side, the camshaft, the rocker shaft, and the rocker arm machine. Are respectively provided on the intake valve side and the exhaust valve side so as to be symmetric when viewed from the crankshaft direction of the internal combustion engine, and the rotation direction of the camshaft on the intake valve side and the exhaust valve side. Are set to be the same.
[0010]
The second arm includes a base end portion rotatably connected by a connecting member provided on the rocker shaft side, an abutting portion that abuts on the cam, and an operating portion that abuts on the third arm. And a spring for biasing the third arm in a direction in which the second arm comes into contact with the cam is provided between the support shaft and the third arm. preferable.
[0011]
The third arm has a transmission surface portion in contact with the first arm, and the transmission surface portion has a conversion portion whose distance from the center of the support shaft changes in the rotation direction of the third arm. Is preferred.
Further, the variable mechanism displaces the fulcrum by rotating the rocker shaft and moves the corresponding contact portion of the second arm in the circumferential direction of the base circle of the cam, thereby It is preferable to change the rotation phase of the second arm.
[0012]
More preferably, the transmission surface portion has a non-converting portion whose distance from the center of the support shaft does not change in the rotation direction of the third arm, and while the first arm is in contact with the non-converting portion. The swing of the first arm is cancelled even when the second arm is driven to swing.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS. 1 to 12. An internal combustion engine (engine) to which the present invention is applied includes an intake valve and an exhaust valve. Are provided on the intake valve side and the exhaust valve side, respectively. In the following description, the variable valve gear 10 provided mainly on the intake valve side will be described.
[0014]
As shown in FIG. 1, the variable valve operating apparatus 10 includes a camshaft 20 that rotates by receiving a rotational driving force from a crankshaft (not shown), a rocker shaft 21 that is arranged in parallel to the camshaft 20, and a cam. A rocker arm mechanism 23 that opens and closes a valve (intake valve) 11 by a rotational movement of a cam 22 formed on the shaft 20 is provided.
[0015]
The camshaft 20 is configured to rotate in the direction indicated by the arrow R1 in FIG. Further, the rocker shaft 21 is configured to be able to change the phase by a desired angle in the direction indicated by the arrow R2 in FIG. That is, the variable valve operating apparatus 10 is provided with a variable mechanism 25 as shown in FIG. 2, and the phase of the rocker shaft 21 is activated by operating the variable mechanism 25 based on a control signal from an ECU (not shown). Has been changed. Note that such phase change of the rocker shaft 21 may be performed using a motor or hydraulic pressure.
[0016]
As shown in the figure, a connecting member 27 having a spherical universal joint portion 26 such as a stud bolt is attached to the rocker shaft 21.
The rocker arm mechanism 23 includes a first arm 31, a second arm 32, and a third arm (transmission cam) 33 described below.
Among these, the first arm 31 is supported by the rocker shaft 21 so as to be relatively rotatable (swingable). An adjustment screw 35 is provided at the distal end portion 40 of the first arm 31. When the camshaft 20 rotates in the direction indicated by the arrow R1, the distal end of the adjustment screw 35 is lowered to open the valve 11. Drives in the valve direction. The adjustment screw 35 can adjust the play between the first arm 31 and the valve 11.
[0017]
Further, as shown in FIG. 1, a force transmission unit 37 including a force transmission member 36 such as a roller is provided in the vicinity of the adjustment screw 35.
As shown in FIG. 2, the first arm 31 has shaft fitting portions 41 and 42 through which the rocker shaft 21 is inserted, and these shaft fitting portions 41 and 42 are connected to the tip portion 40. It is formed in a bifurcated shape.
[0018]
As shown in FIG. 1, the second arm 32 is provided between the rocker shaft 21 and the camshaft 20. The second arm 32 has a base end portion 50 pivotably attached to the universal joint portion 26 described above, and an operating portion 51 that comes into contact with a relay portion 66 of the third arm 33 described later. ing.
Further, a contact portion 53 having a cam follower 52 such as a roller that is in rolling contact with the cam 22 is provided between the base end portion 50 and the operation portion 51. As a result, the second arm 32 swings around the center C1 of the universal joint portion 26 on the rocker shaft 21 side as the cam 22 rotates.
[0019]
Then, by changing the phase of the rocker shaft 21 by the variable mechanism 25, the base end portion 50 of the second arm 32 is displaced in the circumferential direction of the rocker shaft 21, and accordingly, the contact portion 53 is in the circumferential direction of the cam 22. The rotational phase of the second arm 32 with respect to the cam 22 changes to the retard side or the advance side.
At least a part of the second arm 32 is positioned between the shaft insertion portions 41 and 42 in a state where the contact portion 53 of the second arm 32 is in contact with the base circle 22b of the cam 22. is doing.
[0020]
Thus, according to the configuration in which a part of the second arm 32 is sandwiched between the shaft insertion portions 41 and 42, the contact portion between the second arm 32 and the cam 22, or the second arm 32 and the third arm 33. Even when an unbalanced load occurs in the contact portion or the like, the second arm 32 can be prevented from being displaced in the axial direction of the rocker shaft 21, and problems such as unbalanced wear can be prevented.
[0021]
A support shaft 60 is disposed above the rocker shaft 21 in parallel with the rocker shaft 21, and a third arm (transmission cam) 33 is swingably provided on the support shaft 60. The third arm 33 is urged by the return spring 61 in the counterclockwise direction in FIG. 1, that is, in the direction in which the contact portion 53 of the second arm 32 contacts the cam 22.
[0022]
The third arm 33 is provided with a transmission surface portion 65 that contacts the force transmission portion 37 of the first arm 31 and a relay portion 66 that contacts the operating portion 51 of the second arm 32. The transmission surface portion 65 that functions as a cam surface is displaced in the rotational direction of the third arm 33, that is, in the circumferential direction of the support shaft 60 as the second arm 32 swings.
Therefore, when the second arm 32 swings, the contact position between the force transmission portion 37 and the transmission surface portion 65 is displaced in the circumferential direction of the support shaft 60. That is, when the second arm 32 is swung to the third arm 33 side about the universal joint portion 26 by the convex portion 22a of the cam 22, and the third arm 33 is rotated clockwise via the relay portion 66, the transmission is performed. When the first arm 31 is rotated in the direction of the arrow R3 by the surface portion 65, the valve 1 is opened.
[0023]
More specifically, in the transmission surface portion 65, the distance from the center C2 of the support shaft 60 is constant, and the distance from the center C2 of the support shaft 60 increases toward the distal end portion 33a of the third arm 33. And a conversion unit 71.
Among these, the non-converting portion 70 is formed in an R shape having a constant distance from the center C2 of the support shaft 60 as described above, and as a result, while the force transmitting portion 37 is in contact with the non-converting portion 70. Even if the third arm 33 swings, the force transmitting portion 37 is not displaced, and the swing of the first arm 31 is cancelled.
[0024]
More specifically, the non-conversion unit 70 determines that the swing start timing of the first arm 31 is substantially constant regardless of the phase adjustment amount of the rocker shaft 21 (that is, the advance amount or retard amount of the second arm 32). That section is set so that That is, when the phase of the rocker shaft 21 is changed by the variable mechanism 25, the swing timing of the second arm 32 relative to the cam 22 is advanced or retarded. Such phase adjustment of the second arm 32 is performed. Sometimes the third arm 33 rotates and the contact position of the non-converting portion 70 with respect to the force transmitting portion 37 changes, so that the phase adjustment margin of the second arm 32 is canceled and the swing start timing of the first arm 31 is reached. Can be kept constant.
[0025]
In addition, the force transmission unit 37 and the conversion unit 71 are in contact with each other by forming the conversion unit 71 such that the distance from the center C2 of the support shaft 60 gradually changes with respect to the rotation direction of the third arm 33. In the meantime, the swing of the second arm 32 can be transmitted to the first arm 31 via the third arm 33.
Next, the operation of the variable valve apparatus 10 will be described.
[0026]
FIG. 1 shows a state in which the rocker shaft 21 is driven by the variable mechanism 25 to the retard side from the neutral position N by an angle θ1. In this case, the contact portion 53 of the second arm 32 is displaced by an angle α toward the retard side (left side in FIG. 1) with respect to the cam 22 from the neutral point P1. Further, the operating portion 51 of the second arm 32 is displaced to the left in FIG.
[0027]
In this state, when the camshaft 20 rotates in the direction of the arrow R1, and the convex portion 22a of the cam 22 pushes up the contact portion 53 of the second arm 32 as shown in FIG. It rotates counterclockwise around the center C1 of the center. For this reason, the operation part 51 of the second arm 32 pushes the relay part 66, and the third arm 33 rotates clockwise. Thereby, since the conversion part 71 of the transmission surface part 65 pushes the force transmission part 37, the 1st arm 31 rotates and the valve 11 opens.
[0028]
In this case, as shown in FIG. 1, the force transmission unit 37 is positioned in the vicinity of the conversion unit 71 before the valve is opened, and therefore, when the third arm 33 rotates clockwise, the transmission surface unit of the third arm 33. Of 65, the non-converting part 70 in contact with the force transmitting part 37 is shortened.
For this reason, the first arm 31 starts to be driven in the direction to open the valve 11 while the cam angle is small, and the first arm 31 moves in the direction of the arrow R3 while the force transmission unit 37 contacts the conversion unit 71 over a long range. Pressed. Therefore, a large valve lift amount H1 (shown in FIG. 3) can be obtained.
[0029]
Therefore, in this case, as indicated by a curve L1 in FIG. 4, the valve lift is large and the peak of the valve lift is retarded. In this case, the valve drive is suitable for a large intake amount with high rotation and high load.
FIG. 5 shows a state where the rocker shaft 21 is driven to the neutral position N by the variable mechanism 25. In this case, the contact portion 53 of the second arm 32 coincides with the neutral point P <b> 1 with respect to the cam 22. In this case, the operating portion 51 of the second arm 32 is slightly displaced to the right in FIG. 5 compared to the case shown in FIG. 1, and the third arm 33 is counterclockwise by this amount. Slightly rotates. For this reason, compared with the state shown in FIG. 1, the contact point between the first arm 31 and the third arm 33 is shifted to the non-converting portion 70 side of the transmission surface portion 65.
[0030]
In this state, when the camshaft 20 rotates and the convex portion 22a of the cam 22 pushes up the contact portion 53 of the second arm 32 as shown in FIG. 6, the second arm 32 moves to the center C1 of the universal joint portion 26. It rotates counterclockwise as a fulcrum. For this reason, the operation part 51 of the second arm 32 pushes the relay part 66, and the third arm 33 rotates clockwise. As a result, the conversion part 71 of the transmission surface part 65 pushes the force transmission part 37. The arm 31 is rotated and the valve 11 is opened.
[0031]
In other words, when the valve shown in FIG. 5 is closed, the distance from the force transmitting portion 37 of the first arm 31 to the converting portion 71 is slightly longer, and the force transmitting portion 37 is moved to the non-converting portion 70 than in the case shown in FIG. The contact distance increases. For this reason, when the 3rd arm 33 rotates clockwise, the time when the non-converting part 70 contacts the force transmission part 37 and the 1st arm 31 is not driven increases. Further, when the force transmission unit 37 thereafter starts to contact the conversion unit 71, the first arm 31 is driven and the intake valve 11 is opened.
[0032]
Thus, even when the rocker shaft 21 is driven and the second arm 32 is advanced, the amount corresponding to this advance amount is canceled by the increase of the non-converting portion 70 and opened. The valve timing is the same as that shown in FIG.
On the other hand, the valve lift amount H2 (shown in FIG. 6) at this time is lower than that shown in FIG. 1, and the valve closing timing of the valve is the second arm 32 as shown by the curve L2 in FIG. The valve is advanced in accordance with the amount of advance of the valve, and becomes a valve drive suitable for medium rotation and medium load operation.
[0033]
FIG. 7 shows a state in which the rocker shaft 21 is driven to the advance side by the angle θ2 from the neutral position N by the variable mechanism 25. In this case, the contact portion 53 of the second arm 32 is displaced by an angle β toward the advance side (right side in FIG. 1) with respect to the cam 22 from the claim point P1. Further, the operating portion 51 of the second arm 32 is displaced to the right in FIG. 7, and the third arm 33 is displaced counterclockwise. For this reason, compared with the state of FIG. 5, the non-conversion part 70 which contact | connects the force transmission part 37 among the transmission surface parts 65 of the 3rd arm 33 becomes still longer, and, as a result, the conversion part 71 becomes still shorter.
[0034]
When the camshaft 20 rotates in this state, as shown in FIG. 8, the convex portion 22a of the cam 22 moves the contact portion 53 of the second arm 32 at an earlier timing as the second arm 32 is advanced. The push-up and the second arm 32 rotate counterclockwise with the center C1 of the universal joint portion 26 as a fulcrum. For this reason, the operation part 51 of the second arm 32 pushes the relay part 66, and the third arm 33 rotates clockwise.
[0035]
In this case, the period (distance) of the non-converting portion 70 in contact with the force transmitting portion 37 in the transmitting surface portion 65 of the third arm 33 is long, so that the first arm 3 starts to swing even if the third arm 33 is driven. As a result, the advance time of the second arm 32 is canceled. Further, when the third arm 33 rotates clockwise as the second arm 32 swings, the distance that the force transmission unit 37 contacts the conversion unit 71 is shortened, so that the amount of rotation of the first arm 31 is small. Yes, the valve lift amount H3 (shown in FIG. 8) becomes smaller. For this reason, as shown by a curve L3 in FIG. 4, a valve drive state suitable for low rotation and low load operation is obtained.
[0036]
Further, by setting the second arm 32 to be advanceable with respect to the cam 22 from the state shown in FIG. 7, the cylinder resting state (the valve lift amount is minimal or zero) shown in L4 of FIG. it can. The fuel consumption can be improved by stopping the operation of some cylinders according to the operating state of the engine.
By the way, in the variable valve operating apparatus 10 described above, the rocker shaft 21 is changed by the variable mechanism 25 as shown by the curves L2 and L3 on the basis of the phase from the start to the end of the curve L1 in FIG. When the second arm 32 is advanced with respect to the cam 22 is canceled by increasing the period in which the non-converting portion 70 and the force transmitting portion 37 of the third arm 33 are in contact with each other. The valve opening start time can be made substantially constant.
[0037]
Therefore, according to the variable valve operating apparatus 10, the valve closing timing can be changed while the valve opening timing of the intake valve is fixed. Therefore, by changing the valve closing timing in accordance with the pulsation of the inertial intake air, An increase in the amount of air can be achieved, and an effect of reducing fuel consumption can be obtained.
Inertial intake means that the pressure pulsation generated by the intake action of the piston causes inertia in the intake air in the intake pipe. By utilizing this inertial intake and starting to close the intake valve 11 at the peak time of intake pulsation, fresh air can continue to flow into the cylinder even after the piston passes the bottom dead center, and volume efficiency can be improved. . Since the peak time of the pulsation varies depending on the engine speed, the intake air amount can be increased by starting to close the intake valve 11 in accordance with the peak time.
[0038]
Moreover, by controlling the amount of air optimally, a good combustion state is obtained, and unburned substances and the like are reduced to improve the exhaust gas component.
By the way, the configuration and operation of the variable valve gear 10 provided on the intake side have been described so far. However, in the engine to which the present invention is applied, the exhaust side is similar to the intake side as shown in FIG. In addition, a variable valve gear 110 including a camshaft 120, a rocker shaft 121, and a rocker arm mechanism 123 is provided.
[0039]
Here, the exhaust-side variable valve apparatus 110 is configured to be symmetrical with respect to the intake-side variable valve apparatus 10 when viewed from the crankshaft axial direction. It is comprised similarly to the variable valve apparatus 10 of the side. For this reason, description is abbreviate | omitted about the detailed structure of the variable valve apparatus 110 by the side of exhaust.
The variable valve device 110 is also provided with a variable mechanism (not shown) that changes the phase of the rocker shaft 121 as in the variable valve device 10 on the intake side. The shafts 21 and 121 are configured such that the phases can be adjusted independently.
[0040]
Further, as shown in the figure, the camshafts 20 and 120 are configured to rotate in the same direction on the intake side and the exhaust side. This is because, as shown in FIG. 10, the valve opening timing of the intake valve 11 is made constant and the valve closing timing of the exhaust valve is made constant. This is because the valve overlap is always kept constant even when operated.
[0041]
Here, as described above, since the variable valve device 110 on the exhaust side and the variable valve device 10 on the intake side are configured symmetrically, the rotation of the camshafts 20 and 120 on the intake side and the exhaust side is performed. If the directions are also symmetrical (that is, if the rotation directions of the camshafts 20 and 120 are opposite directions on the intake side and the exhaust side), the valve lift characteristic of the exhaust valve will be the same as that on the intake side (see FIG. 4). . In other words, in this case, when the phase of the rocker shaft is changed, the valve opening timing of the exhaust valve is substantially constant and the valve closing timing is different, so that the valve overlap cannot be kept constant.
[0042]
Therefore, in the present invention, the variable valve device is configured symmetrically on the intake side and the exhaust side, and the rotation directions of the camshafts 20 and 120 are set to be the same, so that the closing timing of the exhaust valve is substantially constant. As a result, the valve overlap with the intake valve 11 is kept substantially constant.
Note that if the variable valve gears are arranged in the same arrangement on the intake side and the exhaust side without making them symmetrical, and the camshaft rotation direction is set in the opposite direction, the valve lift characteristics as shown in FIG. 10 may be obtained. Although possible, such a configuration is not practical. That is, in general, in an engine, there are many cases in which the valve mechanism is forced to be symmetrical between the intake side and the exhaust side due to restrictions on the mechanism of the valve mechanism and layout restrictions. For example, it is desirable to install the variable valve systems symmetrically on the intake side and the exhaust side. Therefore, in the present invention, the variable valve gears are installed symmetrically on the intake side and the exhaust side, and the rotational directions of the camshafts 20 and 120 are set in the same direction on the intake side and the exhaust side. is there.
[0043]
By the way, in the case of the conventional general continuous phase variable valve operating apparatus, if the valve closing timing is retarded, the valve opening timing is also retarded. For this reason, intake and exhaust valve overlap is reduced or eliminated, and a pumping loss occurs.
On the other hand, according to the variable valve gears 10 and 110, the valve closing timing can be advanced or retarded while the valve opening timing of the intake valve 11 is fixed, and the exhaust valve closing timing is set. Since the valve opening timing can be advanced or retarded while the valve is fixed, the effect of increasing the intake air amount can be obtained by delaying the valve closing timing of the intake valve while maintaining the valve overlap. For this reason, the effect of fuel consumption reduction is acquired.
[0044]
Further, by providing such variable valve operating devices 10 and 110, it is not necessary to provide an intake or exhaust throttle for controlling the intake air amount, and the cost can be reduced.
Since the variable valve operating apparatus for an internal combustion engine as one embodiment of the present invention is configured as described above, the operation of the variable valve operating apparatuses on the intake side and the exhaust side is controlled as follows, for example.
(1) Full load or acceleration
In this case, as shown in FIG. 11, both the intake valve 11 and the exhaust valve are controlled so that the valve lift becomes maximum (corresponding to the lift amount L1). As a result, the valve lift characteristics prioritize the intake / exhaust efficiency during full load or acceleration, and the valve lift characteristics prioritize engine performance.
(2) At start-up
In order to improve the startability, it is effective to increase the temperature at the time of compression in the cylinder at the time of cranking. For this reason, at the time of start-up, for example, as shown in FIG. 12, the exhaust valve is controlled to be a high lift L1, and the intake valve 11 is controlled to be a medium lift L2 to a low lift L3. This is because when the engine is running at a low speed, the intake flow rate increases even if the valve lift is slightly reduced if the intake valve closing timing is relatively advanced compared to the high speed operation. This is because the temperature rises.
[0045]
The startability is improved by setting the exhaust valve to the high lift L1 and the intake valve 11 to the medium lift L2 to the low lift L3 when the engine is started.
(3) When post-processing equipment is activated (part 1)
When using an aftertreatment device (for example, an oxidation catalyst) whose purification performance is improved as the exhaust gas temperature is higher, when activating the aftertreatment device, the exhaust valve is set to a high lift L1 as in the above-described start-up. In addition to being controlled, the intake valve 11 is controlled to have a middle lift L2 to a low lift L3. In this case, since the intake flow rate decreases as described above, the air-fuel ratio becomes rich by this amount, and the exhaust temperature can be raised.
(4) When post-processing equipment is activated (part 2)
When the exhaust gas aftertreatment device is activated, the cylinder resting operation is executed by controlling both valve lifts to be zero for some cylinders (usually half of the cylinders, etc.). At this time, when an output equivalent to that in the non-cylinder operation is required, the working cylinder during the cylinder idle operation has a larger work amount per cylinder than in the non-cylinder operation. That is, since the fuel consumption per cylinder is large, the exhaust temperature rises significantly compared with the non-cylinder operation.
(5) Constant speed operation when empty
Further, even when the vehicle is in an empty state and is traveling at a substantially constant speed, similarly to the above, control is performed so that both valve lifts become zero for some cylinders. As a result, some cylinders are in a cylinder resting state. As a result, the operating cylinder is operated at a higher load than the non-operating cylinder, so that fuel consumption is improved and fuel consumption can be reduced.
(6) NOx reduction
Further, during normal operation, the exhaust valve is controlled to have a medium to low lift, and the intake valve 11 is controlled to have a high lift. And by setting it as such a valve lift characteristic, without exhausting all the combustion gas in a cylinder, a part remains, there exists an advantage that internal EGR can be raised and NOx can be reduced.
[0046]
In addition, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation is possible in the range which does not deviate from the meaning of this invention. For example, the intake side and exhaust side variable valve operating apparatuses may be configured as shown in FIG. Here, the variable valve operating apparatus 10A has bifurcated portions 32a and 32b formed on the base end portion 50 side of the second arm 32, and at least a part of the first arm 31 has the bifurcated portions 32a and 32b. It is configured to be located between. Also. Since other configurations, operations, and effects are the same as those of the variable valve operating apparatus 10 of the above-described embodiment, common members are denoted by the same reference numerals and description thereof is omitted.
[0047]
As described above, even when a part of the first arm 31 is sandwiched between the bifurcated portions 32a and 32b, the contact portion between the second arm 32 and the cam 22, or the second arm 32 and the third arm. When an unbalanced load is generated at the contact portion with the arm 33 or the like, the second arm 32 can be prevented from displacing in the axial direction of the rocker shaft 21, so problems such as uneven wear can be prevented.
[0048]
In addition, for example, a configuration as shown in FIG. This variable valve operating apparatus 10B is different from the variable valve operating apparatus 10 of the above embodiment in that the shaft fitting insertion portion 31a of the first arm 31 is not bifurcated. In addition, since the configuration other than this is the same as that of the variable valve operating apparatus 10 of the first embodiment, common members are denoted by the same reference numerals and description thereof is omitted.
[0049]
【The invention's effect】
As described in detail above, according to the variable valve operating apparatus for an internal combustion engine of the present invention, the valve drive phase and the valve lift amount are continuously changed with a relatively simple configuration without reducing the valve overlap. There is an advantage that it can be made (Claim 1).
[0050]
By providing a spring for urging the third arm, the positions of the second arm and the third arm can be held so that the second arm is always in contact with the cam.
Further, by providing a conversion portion that changes the distance from the center of the support shaft on the transmission surface portion of the third arm, the swing amount of the second arm is converted by the third arm and transmitted to the first arm. For this reason, the lift amount of the intake or exhaust valve can be changed by moving the position of the fulcrum of the second arm on the rocker shaft side by the variable mechanism.
[0051]
Further, the drive phase of the intake or exhaust valve can be continuously changed by a variable mechanism that displaces the fulcrum around the axis of the rocker shaft.
While the first arm is in contact with the non-converting portion, even if the second arm is driven to swing, the swing of the first arm is canceled. The valve closing timing can be made substantially the same (claim 5).
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention, showing a state in which a phase is retarded.
2 is a schematic view showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention, and is a top view of FIG. 1. FIG.
FIG. 3 is a schematic view showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention, and is a view showing a valve opening time when the phase is retarded.
FIG. 4 is a diagram showing a relationship between a cam angle and a valve lift of a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention.
FIG. 5 is a schematic diagram showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention, and showing a state in which the phase is neutral.
FIG. 6 is a schematic view showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention, and is a view showing a valve opening time in a phase neutral state.
FIG. 7 is a schematic view showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention, and showing a state in which a phase is advanced.
FIG. 8 is a schematic diagram showing a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention, and is a diagram showing a valve opening time when a phase is advanced.
FIG. 9 is a schematic diagram showing an overall configuration of a variable valve operating apparatus for an internal combustion engine according to an embodiment of the present invention.
FIG. 10 is a diagram for explaining the operation of the variable valve operating apparatus for an internal combustion engine according to the embodiment of the present invention, and is a valve lift diagram of an intake valve and an exhaust valve.
FIG. 11 is a diagram for explaining the operation of the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention, and is a valve lift diagram of the intake valve and the exhaust valve at the time of full load and acceleration.
FIG. 12 is a diagram for explaining the operation of the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention, and is a valve lift diagram of the intake valve and the exhaust valve at the time of starting.
FIG. 13 is a schematic view showing a modification of the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention.
FIG. 14 is a schematic view showing a modification of the variable valve operating apparatus for the internal combustion engine according to the embodiment of the present invention.
[Explanation of symbols]
10, 10A, 10B, 110 Variable valve gear
11 Intake valve
20,120 Camshaft
21,121 Rocker shaft
22, cam
23,123 Rocker arm mechanism
25 Variable mechanism
26 Universal joint
27 Connecting member
31 First arm
32 Second arm
33 Third arm
37 Force transmitter
60 Support shaft
61 Spring
65 Transmission surface
70 Non-conversion part
71 Conversion unit

Claims (5)

A camshaft rotatably provided in the internal combustion engine;
A rocker shaft provided in the internal combustion engine;
A rocker arm mechanism that is driven by a cam formed on the camshaft to open and close an intake valve or an exhaust valve;
The rocker arm mechanism is
A first arm supported swingably on the rocker shaft and capable of driving the intake valve or the exhaust valve;
A second arm driven by the cam and swinging around the rocker shaft side;
A third arm that is swingably provided on a support shaft disposed in the vicinity of the rocker shaft and that is displaced by the swing of the second arm to drive the first arm;
A variable mechanism for displacing the fulcrum of the second arm on the rocker shaft side;
The camshaft, the rocker shaft, and the rocker arm mechanism are provided on the intake valve side and the exhaust valve side, respectively, so as to be symmetrical when viewed from the crankshaft direction of the internal combustion engine. A variable valve operating apparatus for an internal combustion engine, characterized in that the camshaft is set to have the same rotational direction on the exhaust valve side. The second arm includes a base end portion rotatably connected by a connecting member provided on the rocker shaft side, an abutting portion that abuts on the cam, and an operating portion that abuts on the third arm. And configured
2. A spring for urging the third arm in a direction in which the second arm abuts against the cam is provided between the support shaft and the third arm. The variable valve operating apparatus for an internal combustion engine. The third arm has a transmission surface portion in contact with the first arm,
The variable valve operating apparatus for an internal combustion engine according to claim 1 or 2, wherein the transmission surface portion includes a conversion portion whose distance from the center of the support shaft changes in the rotation direction of the third arm. . The variable mechanism displaces the fulcrum by rotating the rocker shaft, and moves the corresponding contact portion of the second arm in the circumferential direction of the base circle of the cam, whereby the second mechanism with respect to the cam. 4. A variable valve operating apparatus for an internal combustion engine according to claim 2, wherein the rotational phase of the arm is changed. The transmission surface portion has a non-converting portion whose distance from the center of the support shaft does not change in the rotation direction of the third arm, and the second arm is in contact with the non-converting portion while the second arm is in contact with the non-converting portion. The variable valve operating apparatus for an internal combustion engine according to claim 3 or 4, wherein the swing of the first arm is canceled even if the arm is driven to swing.

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