JP4508044B2 - Valve operating device for internal combustion engine - Google Patents

Description

  The present invention relates to a valve gear for an internal combustion engine. In particular, the present invention relates to a valve operating device for a direct acting internal combustion engine in which a valve lifter is interposed between a valve stem and a cam.

  2. Description of the Related Art In an internal combustion engine such as an automobile, a direct-acting internal combustion engine valve operating device is known in which a cam is brought into direct contact with a valve lifter and a valve stem of an intake valve or an exhaust valve connected to the valve lifter is pressed (for example, a patent) Reference 1).

The valve gear includes a valve spring disposed between the cylinder head and the valve lifter. When the cam presses the valve lifter, the valve is opened and the valve spring is compressed. When the cam rotates and the pressure on the valve lifter is released, the valve is closed by the spring load of the valve spring. Thus, the valve spring urges the valve in the direction in which the valve is closed, that is, the valve is not separated from the cam.
JP 07-042519 A

  When the valve lift is large or the engine speed is high, the rotational acceleration of the cam increases, so that a large inertial force acts on the valve pressed by the cam.

  If the inertial force acting on the valve becomes larger than the spring load of the valve spring, there is a possibility that a valve improper movement in which the valve moves away from the cam may occur.

  For this reason, conventionally, an illegal movement of the valve is prevented by suppressing the lift amount of the valve. However, if the lift amount of the valve is suppressed, the charging efficiency is lowered accordingly.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a valve operating apparatus for an internal combustion engine that can suppress illegal valve movement even when the lift of the valve is large.

The present invention is a valve operating apparatus for an internal combustion engine that lifts a valve by a swinging motion of a swing cam. This valve operating apparatus for an internal combustion engine is disposed between a lift suppression cam that swings in synchronization with a swing cam, a valve lifter that is connected to a valve and contacts the swing cam, a cylinder head, and a valve lifter. A valve spring that is compressed by a lift and a receiving member that is attached to the valve lifter and moves up and down together with the valve are provided . When the lift direction of the valve is positive , the lift suppression cam slides on the receiving member so that the valve follows the swinging motion of the swing cam during the period in which the valve motion generates a negative acceleration. The lift suppressing cam and the receiving member are configured so that the lift suppressing cam does not slide on the receiving member during a period when the valve is not lifted.

According to the present invention, when the lift direction of the valve is positive , the lift suppression cam receives the valve so that the valve follows the swing motion of the swing cam during a period in which the valve motion generates a negative acceleration. Since it slides on the member, it is possible to suppress illegal movement of the valve even when the lift of the valve is large. Further, since the lift suppression cam and the receiving member are configured so that the lift suppression cam does not slide on the receiving member during a period when the valve is not lifted, generation of friction between the lift suppressing cam and the receiving member can be suppressed. At the same time, the lift suppression cam can be reduced in size, and the inertial mass due to the swinging motion of the lift suppression cam can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
With reference to FIGS. 1 and 2, a valve gear (hereinafter referred to as “valve gear”) 100 for an internal combustion engine according to Embodiment 1 of the present invention will be described. FIG. 1 is a view showing an outline of the valve operating apparatus 100, and FIG. 2 is a view showing a swing cam driving mechanism for driving a swing cam in the valve operating apparatus 100. FIG.

  The valve gear 100 is a device that lifts the valve 3 in an internal combustion engine such as an automobile. The valve operating apparatus 100 is a direct acting apparatus that opens and closes the valve 3 by directly pressing the valve lifter 2 of the valve 3 by a swing cam 1 that swings in conjunction with a crankshaft (not shown). The valve 3 and the valve lifter 2 are connected via a valve stem 3a.

  The valve operated by the valve operating apparatus 100 is an intake valve or an exhaust valve, and either valve may be used. Therefore, the valve described below refers to either an intake valve or an exhaust valve.

  A valve spring 4 attached to the valve lifter 2 is arranged between the valve lifter 2 and the cylinder head 7, and the valve spring 4 is compressed by the lift of the valve 3.

  The swing cam 1 is provided for each valve lifter 2 and swings by a swing cam drive mechanism 10 shown in FIG. The swing cam drive mechanism 10 will be described below. A drive shaft 11 extending in the cylinder row direction is inserted through the swing cam 1. The drive shaft 11 rotates about the axis in conjunction with the crankshaft. A drive shaft eccentric portion 12 is fixed or integrally formed on the outer periphery of the drive shaft 11. The drive shaft eccentric portion 12 is provided such that the shaft center X is eccentric with respect to the rotation center Y of the drive shaft 11. A first link 15 is slidably provided on the outer periphery of the drive shaft eccentric portion 12.

  On the outer periphery of the control shaft 13 provided in parallel with the drive shaft 11, a rocker arm 14 is externally swingably mounted. One end 14a of the rocker arm 14 and the tip 15a of the first link 15 are linked via a pin 17a. The other end 14b of the rocker arm 14 is linked to one end 16a of the second link 16 by a pin 17b, and the other end 16b of the second link 16 is linked to the swing cam 1 by a pin 17c.

  By configuring the swing cam drive mechanism 10 in this way, when the drive shaft 11 rotates in conjunction with the rotation of the crankshaft, the shaft center P of the drive shaft eccentric portion 12 serving as the rotation center of the first link 15 is changed. It turns around the rotation center Q of the drive shaft 11. As a result, the rocker arm 14 linked to the tip 15a of the first link 15 swings. The rocking motion of the rocker arm 14 is transmitted to the rocking cam 1 via the second link 16, and the rocking cam reciprocates, that is, rocks within a predetermined rotation angle range.

  When the swing cam 1 swings so that the position of contact with the valve lifter 2 changes from the base portion 1 a to the peak portion 1 b (hereinafter referred to as “outward movement”), the swing cam 1 is moved to the valve lifter 2. Press. As a result, the valve stem 3 connected to the valve lifter 2 is pushed down, and the valve 3 starts to lift and opens. At this time, the valve spring 4 disposed between the cylinder head 7 and the valve lifter 2 is compressed by the lift of the valve 3.

  After the swing cam 1 swings to a position where the lift amount of the valve 3 is maximized, the swing cam 1 is in the reverse direction, that is, the contact position between the swing cam 1 and the valve lifter 2 changes from the peak portion 1b to the base portion. It swings so as to change to 1a (hereinafter referred to as “return movement”). As a result, the pressing force of the swing cam 1 against the valve lifter 2 is released, the valve lifter 2 is pressed against the swing cam 1 by the urging force of the valve spring 4, and the valve 3 is closed.

  As described above, the valve 3 is opened by the pressing force of the swing cam 1 against the valve lifter 2 and is closed by the urging force of the valve spring 4. Further, the valve spring 4 presses the valve lifter 2 against the swing cam 1 by the urging force of the valve spring 4 so that the valve lifter 2 is not separated from the swing cam 1.

  Here, FIG. 3 shows a change in the acceleration of the valve lift with respect to the cam angle of the rocking cam 1 when the rocking cam 1 reciprocates once. The period of the swing cam angle 0 ° to 180 ° on the horizontal axis indicates the forward movement of the swing cam 1, and the period of 180 ° to 360 indicates the backward movement of the swing cam 1. The acceleration of the valve lift is positive when the swing cam 1 presses the valve 3 via the valve lifter 2 and when the force that the swing cam 1 presses the valve 3 via the valve lifter 2 is released. That is, the case where the valve 3 is pressed against the swing cam 1 via the valve lifter 2 by the urging force of the valve spring 4 is expressed as negative acceleration.

  As can be seen from FIG. 3, the acceleration of the valve lift is negative before and after the maximum lift. During a period of a predetermined swing angle before the maximum lift, the swing cam 1 is decelerated to change the swinging direction. Therefore, the force that the swing cam 1 presses the valve 3 via the valve lifter 2 is released, and negative acceleration is generated. Also during the period of a predetermined swing angle after the maximum lift, a negative acceleration occurs because the force with which the swing cam 1 presses the valve via the valve lifter 2 is released.

  In the negative acceleration region of the valve lift, the valve lifter 2 is not separated from the swing cam 1 by the urging force of the valve spring 4. However, when the lift amount of the valve 3 is large or when the engine speed is high, the negative acceleration of the valve lift increases, and the valve lifter 2 connected to the valve 3 moves away from the swing cam 1 to generate the illegal movement of the valve. There are things to do. That is, as shown in FIG. 4, the lift amount of the valve 3 is larger than the set maximum lift.

  Therefore, as shown in FIG. 1, the valve operating apparatus 100 includes a lift suppression cam 5 that swings in synchronization with the swing cam 1, as a configuration for suppressing the valve illegal movement in the negative acceleration region of the valve lift. And a cam follower 6 as a receiving member that moves up and down together with the valve. The lift suppression cam 5 slides on the cam follower 6 so that the valve 3 follows the swing motion of the swing cam 1.

  The lift suppression cam 5 is set to have a cam shape and an arrangement with respect to the swing cam 1 so as to slide on the cam follower 6. However, when the lift suppression cam 5 is shaped so that the lift suppression cam 5 always slides on the cam follower 6 as shown in FIG. Will lead to an increase.

  Therefore, the lift restraining cam 5 is slid against the cam follower 6 so as to slide on the cam follower 6 during a predetermined swinging angle of the swinging angle of the swinging cam 1 corresponding to the end of lift from the start of lift of the valve. It is preferable to set the arrangement. Most preferably, the cam follower 6 slides in the negative acceleration region of the valve lift where there is a high possibility of incorrect valve movement, that is, the period during which the pressing force that presses the valve is released. It is preferable to set the cam shape and the arrangement with respect to the swing cam 1. By configuring the lift suppression cam 5 in this way, the swing outermost diameter of the lift suppression cam 5 can be set smaller than the swing outermost diameter of the swing cam 1. Thereby, the inertial mass by the rocking | fluctuation motion of the lift suppression cam 5 can be reduced. In addition, when the lift suppression cam 5 and the cam follower 6 do not always slide, there is an advantage that the generation of friction between them can be suppressed.

  The lift suppression cam 5 may be arranged in any manner as long as it swings in synchronization with the swing cam 1 and slides with the cam follower 6, but is formed integrally with the swing cam 1. Is preferred. By making the lift suppression cam 5 and the swing cam 1 into an integral structure, the configuration of the valve gear 100 can be simplified, and the manufacturing cost can also be reduced.

  The cam follower 6 includes a curved portion 6 a that is curved along the swing direction of the lift suppression cam 5, and is attached to the valve lifter 2. The lift suppression cam 5 slides on the inner surface 6 b of the curved portion 6 a of the cam follower 6. The method for attaching the cam follower 6 to the valve lifter 2 is not particularly limited, such as fixing using an attachment member or welding.

  The operation of the valve gear 100 will be described with reference to FIG. First, the operation of the valve gear 100 in the forward movement of the swing cam 1 will be described. In FIG. 6, the operation changes from FIG. 6A to FIG. 6E of the maximum lift.

  In FIG. 6A and FIG. 6B, the contact position between the swing cam 1 and the valve lifter 2 is the base portion 1a, so that the valve does not operate.

  In FIG. 6C, the contact position between the swing cam 1 and the valve lifter 2 changes from the base portion 1a to the peak portion 1b, so that the valve lifter 2 is pressed by the swing cam 1 and the lift of the valve 3 starts. At this time, the lift suppression cam 5 does not slide on the cam follower 6 yet.

  In FIG. 6D, where the rocking cam 1 reaches the maximum lift, the rocking cam 1 is in a decelerating state, that is, the rocking cam 1 is braked. Is a state of a negative acceleration region in which the force pressing the valve 3 via the valve lifter 2 is released. Therefore, the valve 3 being pressed by the swing cam 1 via the valve lifter 2 is likely to be separated from the swing cam 1 by inertial force. However, since the lift suppression cam 5 comes into contact with the cam follower 6, the lift amount of the valve 3 is restricted and does not exceed the lift amount set by the swing cam 1. Thus, the lift suppression cam 5 and the cam follower 6 act so as to compensate for the urging force of the valve spring 4 that urges the valve lifter 2 so that the valve 3 does not move away from the swing cam 1.

  In FIG. 6 (e) at the time of the maximum lift at which the negative acceleration of the valve lift is maximum, the lift suppression cam 5 is in contact with the cam follower 6, so that the lift amount of the valve 3 is restricted and the maximum lift amount is not exceeded. Absent.

  Next, the operation of the valve gear 100 in the backward movement of the swing cam 1 will be described. In FIG. 6, it is the operation | movement which returns to FIG. 6 (a) from the maximum lift of FIG.6 (e).

  In the change from FIG. 6E to FIG. 6D, the contact position between the swing cam 1 and the valve lifter 2 changes from the peak portion 1b toward the base portion 1a. Thus, the force that presses the valve 3 is released, and negative acceleration is generated. At this time, when the rotational acceleration of the swing cam 1 is large, the valve 3 cannot follow the swing motion of the swing cam 1 and tends to move away from the swing cam 1. However, since the lift suppression cam 5 contacts and presses against the cam follower 6, the valve lifter 2 to which the cam follower 6 is attached is moved in the direction in which the valve 3 is closed. Accordingly, the valve 3 operates following the swing cam 1 without leaving the swing cam 1. Thus, the lift suppression cam 5 and the cam follower 6 act so as to compensate for the urging force of the valve spring 4 that urges the valve lifter 2 so that the valve 3 does not move away from the swing cam 1.

  In FIG. 6C, sliding between the lift suppression cam 5 and the cam follower 6 is released. However, since the rotational acceleration of the rocking cam 1 becomes small and enters a positive acceleration region state, the valve 3 does not move away from the rocking cam 1.

  6 (b) and 6 (a), the contact position between the swing cam 1 and the valve lifter 2 is the base portion 1a, and the lift of the valve 3 is completed.

  The valve lift requires a larger lift amount to improve the charging efficiency as the engine speed increases so that the opening time of the valve 3 becomes shorter. In such a situation, the inertial force acting on the valve also increases. Unauthorized movement is likely to occur.

  However, according to the valve operating apparatus 100 according to the first embodiment described above, the urging force of the valve spring 4 can be supplemented by the lift suppression cam 5 sliding on the cam follower 6, so that the valve 3 is not swung. It is possible to follow the swinging motion of the moving cam 1 and to suppress the valve improper motion.

  In other words, by setting a period during which the lift suppression cam 5 and the cam follower 6 slide, the lift amount of the valve 3 can be increased and the engine speed can be increased. Therefore, it is possible to achieve both the improvement of the charging efficiency by the large lift and the high engine speed.

  Hereinafter, another aspect of the first embodiment will be described with reference to FIGS.

  First, the aspect shown in FIG. 7 will be described. 7A is a front view showing the outline of the valve operating apparatus 100, FIG. 7B is a rear view showing the outline of the valve operating apparatus 100, and FIG. 7C is a cross-sectional view taken along the line cc in FIG. FIG. When the valve operating apparatus 100 according to the first embodiment is applied to a plurality of valves in one cylinder, for example, the two valves 3 and 3 ′, as shown in FIG. One lift suppression cam 5 and one cam follower 6 that slides on the lift suppression cam 5 are used for the swing cams 1c and 1d. In this case, the lift suppression cam 5 is preferably disposed between the two swing cams 1c and 1d. By disposing the lift suppression cam 5 between the two swing cams 1c and 1d, the inclination of the two valves is smaller than when the lift suppression cam 5 is disposed outside the two swing cams 1c and 1d. Can be prevented, and the occurrence of a lift difference between the valves 3, 3 'can be prevented.

  The cam follower 6 has a mounting portion 6c formed integrally with the curved portion 6a. As shown in FIG. 7 (c), the arc-shaped recesses 6d and 6e are formed in the mounting portion 6c. ing. The cam follower 6 is attached to both the valve lifters 2a and 2b by fitting the outer peripheries of the recesses 6d and 6e and the valve lifters 2a and 2b and covering the outer peripheries of the valve lifters 2a and 2b with the attachment portion 6c. As a result, the cam follower 6 can move up and down together with the valve lifters 2a and 2b. As shown in FIG. 7 (a), if the mounting portion 6c is provided with a claw 18 and the claw 18 is used to hold the valve lifters 2a and 2b, the cam follower 6 can be firmly fixed to the valve lifters 2a and 2b. Can do.

  Next, the aspect shown in FIG. 8 will be described. As shown in FIG. 8, one of the two oscillating cams 1c, 1d is oscillated in conjunction with the other oscillating cam 1d that is connected to the oscillating cam drive mechanism 10 and oscillates. It is a cam to do. When the lift suppression cam 5 is disposed between the two swing cams 1c and 1d, it is preferably provided offset from the center position of the two swing cams 1c and 1d toward the swing cam 1c. Thus, by arranging the lift suppression cam 5 on the side of the swing cam 1c that swings in conjunction, there is no possibility of interference between the curved portion 6a of the cam follower 6 and the swing cam drive mechanism 10, and the swing cam The layout design of the drive mechanism 10 is facilitated. Also, the integral formation of the lift suppression cam 5 and the swing cam 1c is facilitated.

  Next, the aspect shown in FIG. 9 will be described. As shown in FIG. 9, the swing cam 1 is preferably arranged with the swing center Q of the swing cam 1 offset from the axis T of the valve 3 by a predetermined distance. By disposing the swing cam 1 in this way, the contact movement length between the swing cam 1 and the valve lifter 2 can be increased, so that the lift amount of the valve 3 can be increased. When the lift amount of the valve 3 is increased, the valve improper movement is likely to occur. However, according to the valve gear 100 according to the first embodiment, the valve improper movement is performed as described above even if configured in this way. Can be suppressed. Thus, the valve operating apparatus 100 is particularly effective in a configuration in which the swing center Q of the swing cam 1 is offset from the shaft T of the valve 3.

(Embodiment 2)
Next, a valve gear 200 for an internal combustion engine according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 10 is a diagram showing an outline of the valve gear 200.

  The configuration of the valve gear 200 according to the second embodiment is substantially the same as that of the valve gear 100 according to the above-described first embodiment, and will be described below with a focus on the differences. In addition, the same code | symbol as the valve operating apparatus 100 is attached | subjected to the same structure, and description is abbreviate | omitted.

  The difference between the valve operating apparatus 200 and the valve operating apparatus 100 according to the second embodiment is that the variable valve operating mechanism 20 that variably controls the lift amount of the valve 3 according to the operating state of the internal combustion engine. It is a point to prepare.

  The variable valve mechanism 20 will be described below. A control shaft eccentric portion 21 is fixed or integrally formed with the control shaft 13 on the outer periphery of the control shaft 13. The shaft center R1 of the control shaft eccentric portion 21 is provided eccentric to the rotation center R2 of the control shaft 13. A rocker arm 14 is fitted on the outer periphery of the control shaft eccentric part 21 so as to be swingable about the axis R1 of the control shaft eccentric part 21.

  One end of the control shaft 13 is provided with an actuator (not shown) such as a motor via a gear or the like. When the control shaft 13 is rotationally controlled by the actuator, the shaft center R1 of the control shaft eccentric portion 21 serving as the rocking center of the rocker arm 14 turns around the rotation center R2 of the control shaft 13, and the rocker arm 14, the first link 15, And the attitude | position of the 2nd link 16 changes. As the distance between the swing center Y of the swing cam 1 and the rotation center R1 of the rocker arm 14 changes, the swing characteristics of the swing cam 1 change.

  For example, at the time of engine low load operation, the actuator is operated to rotate the control shaft 13 so that the rotation center R1 of the rocker arm 14 moves upward. Thereby, the front-end | tip part 22 of the rocking | fluctuation cam 1 rotates forcibly upward via the 2nd link 16, as shown to Fig.11 (a). As a result, the lift operating angle, which is the range in which the valve 3 is opened and closed, of the swing angle of the swing cam 1 is reduced.

  Further, during engine high load operation, the actuator is operated to rotate the control shaft 13 so that the rotation center R1 of the rocker arm 14 moves downward. Thereby, the front-end | tip part 22 of the rocking | fluctuation cam 1 rotates forcibly below via the 2nd link 16, as shown in FIG.11 (b). This increases the lift operating angle.

  In this way, by operating the actuator and adjusting the rotation center R1 of the rocker arm 14, the position of the distal end portion 22 of the rocking cam 1 can be freely set. The position can be changed. Thereby, even if the swing angle amount of the swing cam 1 is the same, the lift operating angle can be changed, so that the lift amount of the valve changes.

  As described above, by controlling the rotation angle phase of the control shaft 13 and the control shaft eccentric portion 21 by the actuator, the lift operating angle and the lift amount of the valve 3 can be continuously changed.

  The rotation angle phase of the control shaft 13 is detected by a position detection sensor (not shown) and optimally controlled by a controller (not shown) according to the engine operating state.

  FIG. 12 shows a variable control program for the valve lift amount. FIG. 12 is a graph showing the relationship between the maximum valve lift set by the variable valve mechanism 20 and the engine speed. Thus, the maximum lift amount of the valve is calculated by a function having the engine speed as an argument. As shown in FIG. 12, the valve lift is required to have a larger lift amount as the engine speed is shorter and the opening time is shorter. As the lift amount is larger, the inertial force generated in the valve 3 is larger, so that the valve improper movement is likely to occur.

  For this reason, in the valve operating apparatus 200, when the maximum lift amount of the valve 3 set by the variable valve mechanism 20 is equal to or larger than the predetermined lift amount (region a in FIG. 12), that is, a high lift that is likely to cause an illegal movement of the valve. In the case of operation, the lift suppression cam 5 and the cam follower 6 are arranged so that the lift suppression cam 5 slides on the cam follower 6 as shown in FIG. FIGS. 13A and 13B are diagrams showing changes from the start of lift of the valve 3 to the maximum lift in chronological order (the state at the left end in the figure is at the start of lift).

  Further, in the case of a low lift operation in which the maximum lift amount of the valve 3 set by the variable valve mechanism 20 is less than a predetermined lift amount (region b in FIG. 12), there is a low possibility that the valve improper movement will occur. Therefore, the lift suppression cam 5 is prevented from sliding on the cam follower 6 as shown in FIG.

  As described above, in the valve gear 200 according to the second embodiment, it is determined whether or not the lift suppression cam 5 is caused to slide on the cam follower 6 based on the maximum lift amount of the valve 3 set by the variable valve mechanism 20. To do. By configuring the lift suppression cam 5 to slide on the cam follower 6 only when the maximum lift amount of the valve 3 is equal to or greater than a predetermined lift amount, the maximum outer diameter of the lift suppression cam 5 can be reduced, The configuration of the valve device 200 can be simplified.

  Note that there is a possibility that the maximum lift amount (predetermined lift amount in FIG. 12), which is a boundary of whether or not the lift suppression cam 5 slides on the cam follower 6, varies depending on the clearance of each part, the rigidity of the member, and the like. Therefore, in order to prevent variation in the predetermined lift amount that is the boundary value, the variable control program for the valve lift amount is changed to provide hysteresis before and after the predetermined lift amount as shown in FIG. Specifically, an area where the maximum lift amount is constant is provided before and after the predetermined lift amount regardless of the engine speed (N1 to N2). As a result, it is possible to clearly distinguish the region in which the lift suppression cam 5 slides on the cam follower 6 (high lift operation) and the region in which the lift suppression cam 5 does not slide (low lift operation). Can be prevented.

  According to the valve operating apparatus 200 according to the second embodiment described above, since the variable valve operating mechanism 20 is provided, the valve lift amount can be continuously changed. During the high valve lift operation by the variable valve mechanism 20, the lift suppression cam 5 and the cam follower 6 slide to suppress the valve improper movement. In this way, by combining the variable valve mechanism 20 and the mechanism that suppresses the valve improper movement, an engine with higher performance can be obtained.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The present invention can be used for an internal combustion engine mounted on a vehicle.

(A) It is a figure which shows the outline of the valve gear 100 which concerns on Embodiment 1 of this invention. FIG. 3 is a diagram showing a swing cam drive mechanism 10. It is a graph which shows the change of the acceleration of a valve lift with respect to the cam angle of a rocking cam when a rocking cam reciprocates once. It is a graph which shows the change of the valve lift amount with respect to the cam angle of a rocking cam. It is a figure which shows the one aspect | mode of a lift suppression cam. It is a figure which shows operation | movement of the valve operating apparatus. It is a figure which shows the other aspect of the valve operating apparatus. It is a figure which shows the other aspect of the valve operating apparatus. It is a figure which shows the other aspect of the valve operating apparatus. It is a figure which shows the outline of the valve gear 200 which concerns on Embodiment 2 of this invention. It is a figure which shows the rocking | swiveling start position of the rocking cam by a variable valve mechanism. It is a graph which shows the relationship between the maximum lift amount of a valve set by a variable valve mechanism, and an engine speed. (A) It is a figure which shows operation | movement of the valve gear 200 at the time of high lift operation. (B) It is a figure which shows operation | movement of the valve operating apparatus 200 at the time of low lift driving | operation. It is a graph which shows the other aspect of the graph of FIG.

Explanation of symbols

100, 200 Valve-operating device 1 for internal combustion engine Swing cam 1a Base portion 1b Mountain portion 2 Valve lifter 3 Valve 3a Valve stem 4 Valve spring 5 Lift suppression cam 6 Cam follower 6a Cam follower curved portion 6b Cam follower inner surface 10 Swing cam drive mechanism 11 Drive Shaft 12 Drive shaft eccentric portion 13 Control shaft 14 Rocker arm 15 First link 16 Second link 20 Variable valve mechanism 21 Control shaft eccentric portion

Claims (14)

In a valve operating apparatus for an internal combustion engine that lifts a valve by a swinging motion of a swing cam,
A lift suppression cam that swings in synchronization with the swing cam;
A valve lifter connected to the valve and in contact with the swing cam;
A valve spring disposed between a cylinder head and the valve lifter and compressed by a lift of the valve;
A receiving member attached to the valve lifter and moving up and down with the valve;
When the lift direction of the valve is positive , the lift suppression cam slides on the receiving member so that the valve follows the swinging motion of the swing cam during a period in which the valve motion generates a negative acceleration. A valve operating apparatus for an internal combustion engine , wherein the lift suppressing cam and the receiving member are configured so that the lift suppressing cam does not slide on the receiving member during a period in which the valve does not lift . In a valve operating apparatus for an internal combustion engine that lifts a valve by a swinging motion of a swing cam,
A lift suppression cam that swings in synchronization with the swing cam;
A receiving member that moves up and down together with the valve;
A variable valve mechanism that variably controls the lift amount of the valve according to the operating state of the internal combustion engine,
When the maximum lift amount of the valve set by the variable valve mechanism is greater than or equal to a predetermined lift amount so that the valve follows the swinging motion of the swing cam, the lift suppression cam acts on the receiving member. A valve operating apparatus for an internal combustion engine characterized by sliding. The maximum lift amount of the valve set by the variable valve mechanism is calculated by a function having an engine speed as an argument,
The valve operating apparatus for an internal combustion engine according to claim 2, wherein a hysteresis is provided before and after the predetermined lift amount of the function. The variable valve mechanism is
A drive shaft that rotates in conjunction with the crankshaft, a drive shaft eccentric portion provided eccentrically on the outer periphery of the drive shaft, a control shaft provided in parallel with the drive shaft, and a swing on the outer periphery of the control shaft A rocker arm that is externally fitted and swingable, a first link that is slidably fitted to the outer periphery of the drive shaft eccentric portion and that is linked to one end of the rocker arm, the other end of the rocker arm, and the rocker A second link that links the moving cam,
The internal combustion engine according to claim 2 or 3, wherein the valve lift amount is continuously changed by changing a distance between a swing center of the swing cam and a rotation center of the rocker arm. Valve gear. The receiving member has a curved portion arranged to be curved along the swinging direction of the lift suppressing cam,
The valve operating device for an internal combustion engine according to any one of claims 1 to 4, wherein the lift suppression cam slides on an inner surface of the curved portion. The said lift suppression cam slides on the said receiving member during the period of the predetermined rocking | swiveling angle among the rocking angles of the said rocking cam corresponding to the lift completion | finish from the lift start of the said valve | bulb. Item 6. The valve operating apparatus for an internal combustion engine according to any one of Items 5 to 6. 7. The valve operating apparatus for an internal combustion engine according to claim 6, wherein the predetermined swing angle is a period in which a pressing force with which the swing cam presses the valve is released. When the swing cam is swinging the forward path, the lift suppression cam is brought into contact with the receiving member to suppress the lift amount of the valve from being higher than the lift amount by the swing cam;
8. The valve according to claim 7, wherein when the swing cam is swinging along the return path, the valve follows the swing motion of the swing cam by the lift suppression cam pressing the receiving member. A valve operating apparatus for an internal combustion engine as described. The valve operating apparatus for an internal combustion engine according to any one of claims 1 to 8, wherein the urging force of the valve spring is compensated by sliding the lift suppression cam on the receiving member. 10. The valve operating apparatus for an internal combustion engine according to claim 1, wherein the swing cam and the lift suppression cam are integrally formed. Multiple valves are provided in one cylinder,
The swing cam is provided for each valve,
The lift suppression cam slides with the receiving member that moves up and down together with two of the plurality of valves, and is disposed between two swing cams provided on the two valves. The valve gear for an internal combustion engine according to any one of claims 1 to 10. One of the two swing cams is a cam that swings in conjunction with the other swing cam;
12. The valve operating apparatus for an internal combustion engine according to claim 11, wherein the lift suppression cam is disposed offset from a center position of the two swing cams to one swing cam side. The valve operating apparatus for an internal combustion engine according to any one of claims 1 to 12, wherein an outermost swinging diameter of the lift suppression cam is smaller than an outermost swinging diameter of the swinging cam. . 14. The internal combustion engine according to claim 1, wherein the swing cam is disposed with a swing shaft center of the swing cam offset from the valve shaft. Valve device.

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